Operative Technique in Plastic Surgery – Kevin C.Chung

chemical prophylaxis.
■ Mechanical compression is routinely used.
Prosthetic
infection
■ Most common mode of failure in the long term.
■ May coat prosthesis with high doses of antibiotic bone cement
at time of revision for local antibiotic delivery.
POSTOPERATIVE CARE
■ Mobilization and weight bearing depend on the extent of surgery.
■ Extremity elevation is recommended while patient is in bed.
■ Range of motion and therapy may begin the first 1 to 2 weeks for distal femur
reconstructions.
■ Proximal tibia reconstructions require strict knee extension for 6 weeks to
allow patellar tendon healing. Gradual knee flexion is begun at 6 weeks and
progresses under the supervision of a physical therapist.
■ May administer antibiotics while drains are in place.
OUTCOMES
■ Oncological outcomes include local recurrence and metastasis. Surveillance
for recurrence should be managed by a multidisciplinary sarcoma team. Local
recurrence is higher when margins are positive.1
■ Functional outcomes depend on the extent of tissue resection and patient
overall health status. Most patients will experience some form of disability that
is proportional to the volume of muscle and bone resected.3
■ Distal femur reconstructions do not require extensor mechanism reattachment
and therefore generally function better than proximal tibia reconstructions.
COMPLICATIONS
■ Prosthetic loosening may occur over time necessitating revision surgery.
Generally, implant survival is approximately 80% at 20 years.
■ Local recurrence occurs in a minority of patients and is more common in
patients with positive margins.
■ Deep infection can occur at any time after surgery and requires aggressive
therapy including surgical debridement and antibiotic therapy to achieve limb
salvage. Removal of implants may be necessary to eradicate infection.
REFERENCES
1. Bielack SS, Kempf-Bielack B, Delling G, et al. Prognostic factors in high-

grade osteosarcoma of the extremities or trunk: an analysis of 1,702 patients
treated on neoadjuvant cooperative osteosarcoma study group protocols. J Clin
Oncol. 2002;20(3):776-790.
2. Mankin HJ, Mankin CJ, Simon MA. The hazards of the biopsy, revisited.
Members of the Musculoskeletal Tumor Society. J Bone Joint Surg Am.
1996;78(5):656-663.
3. van Egmond-van Dam JC, Bekkering WP, Bramer JAM, et al. Functional
outcome after surgery in patients with bone sarcoma around the knee; results
from a long-term prospective study. J Surg Oncol. 2017;115(8):1028-1032.

30
CHAPTER
Bony and Soft Tissue
Debridement Around the
Knee
Derek F. Amanatullah, Michael J. Chen, Sahitya K.
Denduluri, and James I. Huddleston
DEFINITION
■ Several conditions affect the knee that requires meticulous soft tissue and bony
debridement for treatment: these include open fractures, osteomyelitis, and
infected total knee arthroplasty (TKA).
■ The expertise of plastic surgeons is frequently needed for soft tissue
management and coverage as the knee is relatively devoid of surrounding soft
tissues in comparison to the muscle bound femur.
ANATOMY
■ The knee is a complex synovial joint composed of two joints: the tibiofemoral
and patellofemoral articulations.
■ The tibiofemoral articulation functions as a hinge joint allowing for flexion
and extension with minimal rotation.
• It transfers body weight from the femur to the tibia and can experience high
joint reaction forces.
■ The patella is the largest sesamoid bone in the human body and transmits
tensile forces from the quadriceps tendon to the patellar ligament.
• By increasing the lever arm of the extensor mechanism from the center of
rotation of the tibiofemoral joint, the patella reduces the amount of work the
quadriceps have to perform to extend the knee.
■ The distal femur is trapezoidal in shape with two condyles that articulate with
the two condyles of the tibial plateau, forming the medial and lateral
compartments of the knee. The majority of the weight is borne through the

medial compartment in a native healthy knee.
■ The mechanical axis of the lower extremity is characterized by a straight line
that passes from the center of the hip through the center of the ankle. Ideally,
this line passes through the center of the knee.
■ Compared to the hip, which is a ball and socket joint, the knee is a relatively
incongruent and relies on both static and dynamic forces for rotational, sagittal,
and coronal stability.
■ The dynamic stabilizers are the muscles and their tendons that cross the knee
joint: these include the hamstrings, the iliotibial band, the pes anserine, the two
heads of the gastrocnemius, the popliteus, and the extensor mechanism.
■ These muscles provide stability through compression of the joint when they
are activated.
■ The hamstrings are composed of the biceps femoris, which crosses the
posterolateral aspect of the knee to insert onto the head of the fibula, and the
semimembranosus, which inserts onto the posteromedial aspect of the tibial
plateau.
■ The semitendinosus, also a hamstring muscle, crosses the medial aspect of
the knee to insert onto the anteromedial proximal tibia along with gracilis and
sartorius to form the pes anserine.
■ The iliotibial band forms from the coalescence of the gluteus maximus and
tensor fascia lata and crosses the knee laterally to insert onto Gerdy tubercle, a
prominence found just below the joint line on the anterolateral tibia.
■ The popliteus originates from the posterior aspect of the proximal tibia and
inserts on to the lateral aspect of the lateral femoral condyle.
■ The two heads of the gastrocnemius cross posteriorly and insert onto the
medial and lateral aspects of the distal femur.
■ The static stabilizers include the ligaments and joint capsule.
■ The medial collateral ligament (MCL) extends from the medial epicondyle of
the femur to the medial aspect of the proximal tibia metaphysis and resists
valgus forces across the knee.
■ The posterolateral corner (PLC) of the knee resists varus and external
rotational forces at the knee: its main components are the lateral collateral
ligament, which extends from the lateral epicondyle of the femur to the
proximal fibular head, the popliteus muscle, and the biceps femoris tendon.
■ The anterior cruciate ligament (ACL) extends from the posteromedial aspect
of the lateral femoral condyle and runs anteriorly to insert in between and in
front of the tibial spines to resist anterior displacement of the tibia relative to

the femur.
■ The posterior cruciate ligament (PCL) runs from the anteromedial aspect of
the medial femoral condyle to the posterior tibial sulcus to resist posterior
displacement of the tibia relative to the femur.
■ The extensor mechanism crosses the knee joint anteriorly and inserts onto the
tibial tubercle.
■ It is composed of the four muscle bellies of the quadriceps, the quadriceps
tendon, the patella, the patellar ligament, and the medial and lateral
patellofemoral retinaculum.
■ It is critical to normal ambulatory function.
■ The superficial femoral artery courses down the femur on the medial side
underneath the sartorius muscle and then passes through the adductor hiatus to
run posterior to the knee in the popliteal fossa where it becomes the popliteal
artery.
■ It provides the sole blood supply to the distal extremity and, if compromised,
risks viability of the leg and foot.
■ The main blood supply to the knee is provided from superior and inferior
lateral genicular arteries, the superior and inferior medial genicular arteries, the
anterior recurrent tibial artery, and the descending genicular artery.
■ These form an anastomotic ring around the patella.
■ The femoral nerve crosses the knee at the medial aspect and becomes the
saphenous nerve supplying sensation to the medial leg and foot.
■ It gives off the infrapatellar branch as it crosses the knee, supplying sensation
to the anteroinferior skin of the knee.
■ This nerve is sacrificed frequently during anterior midline exposures.
■ The sciatic nerve bifurcates just above the popliteal fossa into the tibial and
common peroneal nerves.
■ The tibial nerve joins the popliteal artery and runs directly posterior to the
knee into the leg.
■ The common peroneal nerve crosses laterally and runs superficially around
the neck of the proximal fibula before bifurcating in the deep and superficial
peroneal nerves.
■ The blood supply to the skin of the knee typically arises from medial to lateral.
■ This characteristic deserves careful attention when choosing which incision
to use on a knee with multiple scars.
■ Typically the most lateral incision is chosen so that the potential area of skin

at risk for necrosis is minimized.
PATHOGENESIS
■ Conditions that warrant bony debridement around the knee include open
fractures, chronic osteomyelitis, and periprosthetic joint infections (PJI) after
TKA.
■ Bony debridement is frequently required to prevent or eliminate bacteria
capable of forming biofilms.
■ Bacteria can exist in either a planktonic or biofilm state.
■ In contrast to planktonic microorganisms that are free-floating and rapidly
dividing, a biofilm is characterized by sessile microorganisms that are
embedded in a matrix capable of withstanding both the host’s immune system
and antibiotics.
■ Once bacteria colonize and adhere to the necrotic bone or implants, they can
rapidly form a biofilm.
■ Surgical debridement and removal of any implants are the most efficacious
method to eradicate infection.
Open Fractures
■ Open fractures involving the patella are the most common with an incidence of
6 per million per year in the general population, followed by the distal femur
(5.6 per million per year) and proximal tibia (3.8 per million per year).
■ Road traffic accidents are the primary mechanism.
■ The Gustilo classification system for open fractures was first published in
1976, modified in 1984, and arguably remains the most commonly used system
in orthopedic surgery.1,2
■ This system organizes open fractures in order of worsening prognosis
according to the degree of soft tissue injury, need for soft tissue coverage and
vascular insult.
• Type I: usually low energy, clean, and involve an open wound less than 1
cm in size
• Type II: intermediate-energy, moderately contaminated wounds greater than
1 cm (but less than 10 cm)
• Type III: farm injuries or high-energy fractures with periosteal stripping and
extensively contaminated open wounds greater than 10 cm:
• IIIA wounds can be managed with local wound coverage and skin graft

only.
• IIIB requires rotational or free flap coverage.
• IIIC is associated with arterial damage.
■ The risk of infection has been shown to directly correlate with the fracture
grade.
■ The true extent of underlying soft tissue damage can be appreciated only
after surgical exploration and debridement in the operating room, rather than
in the emergency department.
■ All open fractures are considered contaminated with bacteria, and antibiotics
must be administered as early as possible to prevent infection.
■ Patzakis et al. found an infection rate of 4.7% compared to 7.4% when
antibiotics were given within 3 hours of injury.3
■ The choice of the antibiotic depends on the degree of injury and level of
contamination.
• Intravenous first-generation cephalosporins, such as cefazolin, are
considered first line.
• For Gustilo type III open fractures, extending the coverage to include gram-
negative bacteria by adding an aminoglycoside is commonplace.
Osteomyelitis
■ Osteomyelitis can arise from hematogenous seeding, contiguous spread from
adjacent tissues or joints, or direct inoculation from surgery or trauma.
■ Hematogenous spread of bacteria typically afflicts the metaphysis in
skeletally immature patients but can also seed implants especially in the case
of TKA.
■ Contiguous spread and direct inoculation are seen after direct contamination
from open fractures or surgical procedures.
■ The duration of symptoms designates osteomyelitis as either acute or chronic
and carries important implications with regard to biofilm formation and the
need for surgical debridement.
■ The Cierny-Mader classification system is commonly used to categorize
osteomyelitis based on the extent of bony involvement and status of the host
and carries prognostic value in addition to guiding therapy.
■ Type I involves only the medullary canal.
■ Type II involves a portion of the cortex.
■ Type III is an infection that permeates the cortex into the canal, but the bone

is axially stable.
■ Type IV is similarly permeative but diffuse and places the bone at risk for
fracture.
■ The status of the host is divided into classes A, B, and C.
• The A host is physiologically healthy.
• The B host has compromised physiology from systemic effects of the
infection or medical comorbidities.
• The C host is classified as one in which the morbidity of the treatment is
greater than the disease.
■ Sequestrum is a key pathologic feature of osteomyelitis and represents the
formation of necrotic bone.
■ Bacteria persist in devascularized bone and evade host defenses and
antimicrobial agents.
■ The response of the host is to generally wall of the “bony abscess” by
forming sclerotic bone around the sequestrum.
• This is known as the involucrum.
Infection After Total Knee Arthroplasty
■ Periprosthetic joint infection after TKA is a devastating condition that occurs
in 0.5% to 1.9% of primary TKAs and in 8% to 10% of revision TKAs.4–6
■ The implants provide an excellent surface for bacterial adherence, biofilm
formation, and facilitate the spread of the microorganisms into the surrounding
bone and soft tissues.
■ Infections can occur in the perioperative period or years later after a previously
well functioning TKA.
■ The longer the duration of symptoms, the greater chance of biofilm formation
on the implants and surrounding bone.
■ Symptom duration is commonly separated into acute (3 weeks after surgery
or symptom onset) and chronic (greater than 3 weeks after surgery or
symptom onset).
■ Aggressive surgical debridement and implant removal are key interventions
to treat infections with suspected biofilm formation.
■ Conditions that warrant soft tissue debridement around the knee include open
fractures, septic arthritis, and PJI after TKA.
■ Soft tissue debridement is frequently required to prevent or eliminate bacteria
capable of forming biofilms.

PATIENT HISTORY AND PHYSICAL FINDINGS
Open Fractures
■ Any patient presenting with an open fracture may have associated injuries to
the head, chest, abdomen, pelvis, spine, and extremities.
■ A standard evaluation according to the Advanced Trauma Life Support
guidelines should be performed to evaluate for all potentially life-threatening
injuries.
■ The injury mechanism and details are helpful as high- vs low-energy injuries
predict the extent of bony and soft tissue injury.
■ Low-energy trauma with an open fracture may be associated with a small
inconspicuous poke hole created from inside-out injury.
■ High-energy trauma usually creates a much larger soft tissue defect or frank
degloving of the skin and subcutaneous tissues.
■ A detailed neurovascular exam of the lower limb involved should be done with
focus on evaluating the function of the peroneal and tibial nerves, as well as the
dorsalis pedis and posterior tibial pulses.
■ Any suspicion of vascular injury may direct appropriate testing and
consultation with a vascular surgeon.
■ The soft tissues must be thoroughly inspected.
■ Any fracture with a nearby skin laceration or defect should be considered
open until proven otherwise by surgical evaluation or saline challenge,
utilized in evaluation of traumatic arthrotomy and to determine the presence
of possible external communication with the knee joint.
Osteomyelitis
■ Symptoms and signs of infection should be elicited from the patient including
fever, chills, pain, and swelling.
■ Prior injuries and surgeries including the presence of hardware are important
to identify.
■ The general medical status of the patient including factors that can contribute
to an immunocompromised state should be investigated.
■ The involved limb should be inspected for erythema, swelling, tenderness, and
any opening in the skin that might suggest a draining sinus tract (FIG 1),
which is indicative of chronic osteomyelitis.
■ The neurovascular status of the limb should be evaluated as well as the quality

of the soft tissues.
■ The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are
markers of inflammation that are typically elevated and can be useful for
monitoring response to therapy.
■ The white blood cell count may be normal in cases of chronic infection.
FIG 1 • Draining sinuses as a result of chronic
periprosthetic knee infection.
Infection After TKA
■ PJIs may present acutely after surgery with persistent pain and drainage from
the incision with overlying cellulitis or in a delayed fashion with pain only
(FIG 2).
■ Any pain, stiffness, or instability should warrant consideration of an infection
until proven otherwise.
■ Special attention should focus on the scars about the knee and neurovascular
status of the limb.
■ Multiple scars or poor-quality tissues may necessitate the early involvement of
a plastic surgeon for soft tissue coverage at the time of the planned surgery.
■ An ESR greater than 30 and CRP greater than 10 mg/L are recommended as
the thresholds indicative of chronic infections.
■ If there is any suspicion of PJI, the knee should be aspirated and the fluid sent
for cell count, gram stain, and culture.
■ Importantly, the entry point of the needle for aspiration should not involve
any skin with overlying cellulitis.
■ An aspiration that yields greater than 1700 cells/μL with a neutrophil

percentage greater than 65% is highly suggestive of PJI.
FIG 2 • A. Wound dehiscence postoperative day 14 in a
55-year-old woman with diabetes mellitus s/p total knee
arthroplasty for osteoarthritis. B. Skin necrosis in a 25-
year-old woman after patellofemoral arthroplasty for
post-traumatic arthrosis.
IMAGING
Open Fractures
■ Orthogonal radiographs of affected area including the joint above and below
are important for characterizing the fracture pattern and detecting concomitant
injuries, which are frequent in high-energy trauma.
■ For open extra-articular fractures involving the proximal tibia or distal femur,
plain radiographs are typically all that is required for surgical planning.
■ This is true also for isolated open fractures of the patella.
■ Fractures involving the tibia plateau or distal femoral condyles may be
complex and require computed tomography (CT) to better visual the fracture
patterns and to facilitate optimal surgical planning.
■ CT angiography may be considered if there is suspicion for vascular injury.
■ Magnetic resonance imaging (MRI) is not typically warranted in the acute
period but may be obtained eventually if ligamentous or meniscal damage is
suspected.
Osteomyelitis

■ Radiographs of the involved limb should be obtained in orthogonal planes.
■ In the acute stages of osteomyelitis, the films may be unremarkable.
■ A lytic lesion may be appreciated when enough of the bone has eroded.
■ In chronic situations, the sequestrum may form and is characterized by a
sclerotic focus of infected and necrotic bone that may be surrounded by a
thickening of the surrounding cortex known as the involucrum with
periosteal reaction.
■ Computed tomography is more sensitive and better shows the bony destruction
from the lesion compared to plain films.
■ Magnetic resonance imaging is the most sensitive modality especially in the
early stages of osteomyelitis and will show the extent of intramedullary and
soft tissue involvement.
■ Nuclear bone scans are a sensitive modality but nonspecific.
Infection After TKA
■ Standard radiographs should be obtained and may show osteolysis with
component subsidence or loosening.
■ CT scans, MRI, and nuclear bone scans of little use in preoperative planning
and are not typically needed.
SURGICAL MANAGEMENT
Open Fractures
■ Historically, the practice in orthopedic surgery has been to perform operative
debridement within 6 hours after injury to minimize the risk of infection, but
there may be no advantage to performing the debridement within this time
frame compared to within 24 hours after injury.
■ A thorough debridement by an experienced team during daylight hours with
the appropriate ancillary staff appears to be the critical factor in preventing
infection.
■ All devitalized and contaminated soft and bony tissue must be identified and
removed in a systematic fashion.
■ Bony damage can be highly variable and demands thorough intraoperative
inspection.
■ The decision of whether to retain or discard bony fragments depends on the
remaining soft tissue attachments and involvement of the diaphysis,
metaphysis, and articular margins.

■ Diaphyseal fragments that are stripped of their soft tissue attachments are
effectively devascularized and must be removed, to prevent a nidus for
infection.
■ Metaphyseal fragments, in contrast, have a greater amount of cancellous
bone, which has a greater capacity to revascularize and reintegrate.
• Thus fragments that have minimal contamination may be retained.
■ Cancellous fragments from the articular margins are also retained in order to
anatomically reconstruct the articular surface.
■ Repeat debridement may be necessary 24 or 48 hours later, as the zone of
injury may be more extensive than initially appreciated.
■ Thorough irrigation of the wound after debridement should be performed
using the rationale that “the solution to pollution is dilution.”
■ Once the wound has been debrided back to healthy and viable soft tissue and
bone, attention must be turned to achieving skeletal stabilization.
■ Stabilizing the bone is critical for creating an environment conducive not
only for bone healing but soft tissue healing as well.
■ Stabilization also facilitates early mobilization of adjacent joints, preventing
stiffness and further disability of the injured limb.
■ Options for stabilization will depend on the need for repeat debridement and
soft tissue coverage.
■ The wound should be definitively closed within 48 to 72 hours after fracture
fixation.
■ If injury is a type IIIB open fracture, then external fixation may be preferred
to allow unimpeded access to the wound for soft tissue coverage followed by
definitive internal fixation after the soft tissue envelope has been re-
established and healed.
■ High-energy injuries may result in substantial bony or soft tissue loss from the
initial injury with subsequent debridement procedures creating extensive dead
space.
■ Temporary antibiotic-impregnated polymethylmethacrylate (PMMA) cement
beads can be placed into bony defects and used to deliver high doses of
antibiotics locally.
■ Alternatively, negative pressure wound therapy may be used for similarly
large soft tissue defects.
Osteomyelitis

■ Once the diagnosis of osteomyelitis has been made, it requires proper staging
and a multidisciplinary approach with involvement of infectious disease
specialists, orthopedic surgeons, and plastic surgeons especially if the need for
soft tissue coverage is anticipated.
■ Though acute hematogenous osteomyelitis without associated implants may be
amenable to intravenous antimicrobial therapy alone, infections that are
chronic, are associated with implants, or have an identified sequestrum will
require aggressive surgical debridement if the goal is to eradicate the infection.
■ All dead and nonviable bone should be removed until punctate bleeding bone
is encountered.
■ In the case of intramedullary infections, intramedullary reaming of the canal is
an effective way to debride contaminated bone while preserving cortical
stability.
■ The placement of antibiotic impregnated PMMA cement into the bony and soft
tissue defect to deliver high concentrations of antibiotics to the local tissue has
become standard in the surgical treatment of osteomyelitis.
■ Current techniques include using an antibiotic coated intramedullary nail for
situations involving the medullary canal of the tibia or femur.
■ For well-localized areas and bony defects created after the debridement,
antibiotic-impregnated cement may be packed into the defect or rolled into
beads and attached to suture for easy extraction and to provide a high surface
area to volume ratio in order to maximize drug elution.
■ As the cement is not biodegradable and may continue to elute low levels of
antibiotics for up to 5 years following implantation, a repeat procedure is
typically required for removal of the cement and bone grafting of the defect to
restore skeletal stability and eliminate dead space.
■ Bioabsorbable composites such as calcium sulfate have been examined as an
alternative for dead space fillers and antibiotic delivery vehicles.
• These materials have the benefits of being resorbed and possibly being
replaced by bone, thus potentially eliminating the need for a second
procedure.
• McNally et al. reported an excellent eradication rate of chronic
osteomyelitis treated with one stage debridement and placement of an
antibiotic-impregnated bioabsorbable composite.
Infection After TKA

■ The timing and duration of the infection have important implications with
regard to treatment.
■ An early infection is defined as occurring within 3 weeks after undergoing
the procedure or within 3 weeks after becoming symptomatic in cases of late
hematogenous infection.
■ Late infections are considered all cases that present more than 3 weeks after
the above.
■ The designation of 3 weeks is based on the theoretical time period that it
takes for bacteria to form biofilms.
■ To prevent the morbidity of explanting components, early infections are
typically treated with aggressive debridement and irrigation, exchanging the
polyethylene liner, and retaining the femoral and tibial components.
■ Late infections are most commonly treated by a two-stage exchange
arthroplasty in the United States.
■ The microorganisms by this time have likely adhered to the implants and
formed biofilms, undermining the efficacy of systemic antibiotic therapy.
■ The first stage is composed of removal of all implants, cement, and infected
tissue.
■ Although minimizing bone loss is a priority, the surrounding bone can
contain biofilm and must be debrided back to healthy punctate bleeding bone.
■ Irrigation is then performed, and an antibiotic-impregnated cement spacer is
placed to provide stability, fill dead space, and deliver high concentrations of
local antibiotics.
■ The spacer can be dynamic or static.
• Dynamic spacers involve the use of articulating components that allow for
knee range of motion.
• Static spacers typically involve antibiotic cement-coated humeral nails that
bridge the knee after being placed in the distal femoral and proximal tibial
canals.
• Intravenous antibiotics that target the identified organism are then given for
4 to 6 weeks. Once the patient has finished the course of antibiotics and has
been off therapy for 2 weeks, repeat inflammatory markers are drawn. If the
ESR and CRP are normal, and the clinical exam is negative for any
suspicion of persisting infection, reimplantation is then considered.
• This entails removal of the antibiotic spacer, a thorough repeat irrigation
and debridement and obtaining several intraoperative tissue specimens for

cultures.
• It is important to remove the pseudomembrane that forms between the
cement and the bone in the intramedullary canal with instruments such as a
ringed curette.
• If there is no suspicion for residual infection, the distal femur, proximal
tibia, and patella are prepared for reimplantation of the components, and the
knee is balanced to achieve symmetric flexion and extension gaps.
• Depending on the degree of bone loss encountered, metal augments, stems,
porous cones, or sleeves may be needed to reconstruct the bony defect.
Positioning
■ Supine
■ Tourniquet applied to the thigh
■ Bump under ipsilateral hip to internally rotate the operative leg
■ Povidone-iodine (preferred) or chlorhexidine skin prep
Approach
■ Medial parapatellar approach: most commonly used approach for septic
arthritis of the knee and open periarticular fractures with excellent exposure to
anterior structures of the knee
■ Landmarks: borders of the patella, tibial tubercle
■ Longitudinal midline or medial incision, extending proximally to 5 cm above
superior pole of patella and distally to tibial tubercle depending on desired
exposure
■ Develop skin flaps to expose interval between vastus medialis obliquus and
quadriceps tendon proximally, medial border of patella, and medial border of
patellar tendon distally
■ Medial parapatellar arthrotomy performed sharply or using cautery
■ Depending on amount of exposure needed, patella can be dislocated and
flipped laterally to provide access to lateral joint structures.
T E C H N I Q U E S
■ Bone Infection Management

■ The goal of bony debridement in all of these conditions is to resect all bone
that is necrotic or contaminated with potential biofilm formation.
■ Debridement is typically accomplished with rongeurs, curettes, and
osteotomes, as well as round or pencil tipped high-speed burs.
■ The bur can be especially useful for quick debridement of the bone or
removing a well-fixed implant and cement.
■ The debridement should continue until punctate bleeding bone is
encountered.
■ To allow this, a tourniquet should not be inflated during the debridement, if
possible.
■ Bony resection may be extensive and can create dead space and structural
instability (TECH FIG 1A,B).
■ Antibiotic impregnated PMMA cement may be used to temporarily manage
dead space and deliver antibiotics to the local tissues (TECH FIG 1C).
■ Bone loss management is beyond the scope of this chapter but includes the
following techniques: induced membrane technique, allograft reconstruction,
autograft reconstruction including vascularized fibula, bone transport and
distraction osteogenesis, and primary shortening of the limb.
TECH FIG 1 • A. Bicompartmental knee arthroplasty
being removed for chronic periprosthetic infection. B.
Knee after extensive bony debridement and tibial

tubercle osteotomy required for removal of a
chronically infected total knee arthroplasty. C.
Radiograph showing an antibiotic-impregnated
polymethylmethacrylate spacer placed after removal
of an infected total knee arthroplasty in the first of a
planned two-stage procedure.
■ Soft Tissue Infection Management
Irrigation and Debridement
■ Although there is no consensus, a high volume of low-pressure irrigant
appears to be sufficient, such as with gravity irrigation using cystoscopy
tubing.
■ High-pressure irrigation, though potentially beneficial for removing more
bacteria and debris with less solution, may cause damage to soft tissues and
the bone.
■ Pulsatile devices have also not been shown to improve outcomes compared
to gravity irrigation and may actually have a decreased irrigation rate
overall.
■ Bulb irrigation may not be as efficacious.
■ Normal saline is the favored irrigant, with or without the use of added
antibiotics in the final liter of irrigation.
■ In the setting of open fractures with a traumatic arthrotomy, the amount of
irrigant used generally depends on the extent of injury. For example,
employing the Gustilo classification, type I injuries can be effectively
irrigated with 3 L of saline, type II with 6 L, and type III with 9 L.
■ In open fractures, debridement should involve a systematic inspection of all
tissue types, including the skin, subcutaneous fat, fascia, muscle, and bone.
■ Remove all necrotic tissue until a healthy bleeding wound bed is achieved.
■ Muscle viability can be determined by color, contractility, consistency, and
capacity to bleed.
■ Debridement should be performed sharply, centripetally, and radically,
removing any tissue that may even appear questionably viable.
■ The cortical bone without soft tissue attachments should be removed, as it
will be nonviable, though articular fragments should be retained if joint

reconstruction can be achieved (TECH FIG 2).
■ A repeat debridement can be performed after 24 to 48 hours if tissue
viability or adequacy of initial debridement is in question and at the time of
definitive closure in wounds requiring a muscle flap.
TECH FIG 2 • The knee in FIG 1 after debridement and
placement of an articulating spacer made from
antibiotic-impregnated PMMA.
Adjuncts
■ Hydrogen peroxide
■ May be synergistic in conjunction with chlorhexidine or povidone-iodine
with regard to bactericidal activity
■ Can result in wound complications, local cytotoxicity against healthy
tissue, and increase risk of air embolism
■ Local antibiotics
■ Antibiotic-loaded polymethylmethacrylate (PMMA, bone cement):
vancomycin and aminoglycosides, such as tobramycin and gentamicin, can
be effectively incorporated during mixing process and are thermostable to
withstand the exothermic polymerization of the cement.
• Can be formed into beads and placed into wound bed
■ Implants used for fracture fixation can be coated for delivery to tissues.
■ Antibiotic powder placed directly into wound
■ Negative pressure wound therapy
■ Has a role in wounds left open or closed primarily
■ Reduces edema

■ Improves local microcirculation
■ Can be used to stage coverage for open wounds requiring delayed flap
closure
PEARLS AND PITFALLS
Bone
management
■ Do not strip viable bone. Remove all stripped bone not attached to
cartilage as these represent a nidus for future infection.
Soft tissue
management
■ Maintaining or reconstructing a viable and well-vascularized soft
tissue envelope in the case of open fractures is key to preventing
infection and enhancing bone healing. Maintain all viable bone. Do
not pinch the skin. Use atraumatic technique.
Necrotic
tissue
■ Remove all hardware and nonviable tissue as these represent a
nidus for future infection.
Cartilage
■ Preservation of metaphyseal and periarticular fragments stripped of
soft tissue is the exception as they may reintegrate in contrast to
diaphyseal fragments and may be critical to reconstructing the joint
line or articular surface.
Negative
pressure
wound
dressing
■ Do not apply over bone directly as it can desiccate the location that
requires further debridement. Do not apply in active infection.
Antibiotic
beads
■ Consider for temporary management of an infected wound bed.
Well-fixed
implant
■ Cemented implants should be carefully freed from the underlying
cement with a bur or saw before attempted removal to avoid
fracture of key supporting structures.
Amputation
■ If reconstruction and preservation of the limb are not feasible,
amputation should be strongly considered.
Wound
edges
■ Debride rounded skin to fresh edges to facilitate healing.
Plastic
surgery
■ Consult plastic surgery early in the process of wound closure or
defect management to assess primary, secondary, or flap-based
closure.

POSTOPERATIVE CARE
■ Open fractures
■ Antibiotics should be administered for 24 hours after definitive closure of the
wound.
■ The weight-bearing status of the patient will depend on the type of fixation
used and location of the injury.
■ Diaphyseal fractures treated with intramedullary nailing can typically be
treated with weight bearing as tolerated, whereas periarticular fractures
require several weeks of nonweight bearing to allow anatomic healing of the
articular surface.
■ Early mobilization of neighboring joints is critical to prevent adjacent
stiffness.
■ Osteomyelitis
■ Intravenous antibiotics for at least 6 weeks is typically required with the
choice depending on the sensitivities of the identified microorganism.
■ ESR and CRP levels are monitored at routine intervals.
■ Early mobilization of the patient and maintaining motion at adjacent joints is
similarly critical to overall functional outcome.
■ Infection after TKA
■ Intravenous antibiotics specific to the organism are continued for a minimum
of 6 weeks after the initial debridement and explanation until ESR and CRP
levels have resolved.
■ After the patient has completed antibiotic therapy, the ESR and CRP are
evaluated at least 2 weeks later.
■ Reimplantation is then considered only if the ESR and CRP levels are
normal.
OUTCOMES
■ Open fractures
■ Successful treatment of open fractures depends on the thoroughness of the
debridement, the presence of a well-vascularized soft tissue envelope, and the
bony reconstruction.
■ The overall infection rate for open fractures has been shown to be around 2%
to 4%, whereas Gustilo type IIIC injuries can become infected at rates as high
as 20% to 40%.7,8
■ In open fractures treated with antibiotics at the time of admission, there is no

significant difference in infection rates when debrided within or after 6 hours
of injury.
■ Osteomyelitis
■ Units experienced in the treatment of osteomyelitis typically achieve the best
outcomes.
■ Cierny reported a cure rate of 84% at 2 years of follow-up.9
■ Infection after TKA
■ Eradication of infection following two-stage protocol using an antibiotic
spacer followed by reimplantation has reported success rates between 74%
and 91%.
■ The data on articulating vs static spacers are conflicting; however, some
studies have shown improved patient satisfaction, range of motion, and an
easier exposure at the time of reimplantation when an articulating spacer is
used.
COMPLICATIONS
■ Open fractures can result in infection and osteomyelitis, nonunion, malunion,
hardware failure, and amputation.
■ Inadequate treatment of osteomyelitis can lead to persistent infection, sinus
formation, and malignant transformation.
■ Osteomyelitis may also require amputation.
■ Inadequate treatment of PJI can lead to persistent infection or reinfection
requiring repeat debridement and antibiotic spacer exchange, chronic
suppression with antibiotics if the patient is not a surgical candidate, or
amputation.
REFERENCES
1. Gustilo RB, Anderson JT. Prevention of infection in the treatment of one
thousand and twenty-five open fractures of long bones: retrospective and
prospective analyses. J Bone Joint Surg Am. 1976;58(4):453-458.
2. Gustilo RB, Mendoza RM, Williams DN. Problems in the management of
type III (severe) open fractures: a new classification of type III open fractures.
J Trauma. 1984;24(8):742-746.
3. Patzakis MJ, Wilkins J. Factors influencing infection rate in open fracture
wounds. Clin Orthop Relat Res. 1989;(243):36-40.
4. Bozic KJ, Kurtz SM, Lau E, et al. The epidemiology of revision total knee
arthroplasty in the United States. Clin Orthop Relat Res. 2010;468(1):45-51.

5. Kurtz SM, Lau E, Schmier J, et al. Infection burden for hip and knee
arthroplasty in the United States. J Arthroplasty. 2008;23(7):984-991.
6. Kurtz SM, Ong KL, Lau E, et al. Prosthetic joint infection risk after TKA in
the Medicare population. Clin Orthop Relat Res. 2010;468(1): 52-56.
7. Kim PH, Leopold SS. In brief: Gustilo-Anderson classification. [corrected].
Clin Orthop Relat Res. 2012;470(11):3270-3274.
8. Lenarz CJ, Watson JT, Moed BR, et al. Timing of wound closure in open
fractures based on cultures obtained after debridement. J Bone Joint Surg Am.
2010;92(10):1921-1916.
9. Cierny G. Surgical treatment of osteomyelitis. Plast Reconstr Surg.
2011;127(suppl 1):190S-204S.

31
CHAPTER
Bone Reconstruction of the
Knee
Robert J. Steffner and Raffi S. Avedian
DEFINITION
■ For this chapter, we will be discussing segmental bone loss with a specific
example of a metadiaphyseal hemicortical bone defect below an intact knee
joint.
■ Above and below the knee is a common area for segmental bone loss due to
trauma, tumor, and infection.
■ Bone loss in the proximal tibia with an intact joint that compromises the
extensor mechanism is often best reconstructed with an intercalary fresh frozen
allograft with soft tissue attachments. This facilitates extensor mechanism
reconstruction.
■ Joint loss is generally reconstructed with an allograft-prosthetic composite or
endoprosthetic reconstruction.
ANATOMY
■ Anatomy relevant to reconstruction on the medial knee includes the adductor
tendon insertion on the medial distal femur and the pes anserinus tendons
inserting on the proximal tibia. The surgeon will encounter the femoral artery
and vein just below the medial intermuscular septum moving through the
adductor hiatus to enter the popliteal fossa.
■ Pay close attention to identify and preserve the saphenous nerve branch and
saphenous vein.
■ The medial collateral ligament (MCL) connects the medial distal femur to the
medial proximal tibia. The deep portion of the ligament inserts on the proximal
tibia approximately 1 cm below the joint line. The superficial portion is broad
and inserts on the proximal tibia 6 to 7 cm distal to the joint line.

■ The MCL may need to be reconstructed as part of the surgical procedure.
■ On the lateral knee, the iliotibial band inserts on the proximal lateral tibia at
Gerdy tubercle and the bicep femoris tendon spans the knee to insert onto the
fibular head. Posterior to the bicep femoris tendon lies the common peroneal
nerve. The nerve divides at the anterior fibular neck into deep and superficial
branches.
■ The lateral collateral ligament connects the lateral distal femur to the fibular
head. Reconstruction may be required with bone defect management at the
lateral knee.
■ Soft tissue loss around the proximal tibia can create a precarious situation that
is at increased risk of infection. The surgeon should maintain a low threshold
for soft tissue coverage with a gastrocnemius flap or free tissue transfer.
PATHOGENESIS
■ This technique is applicable to bone loss from bone tumor excision, bone loss
from trauma such as an open fracture, and osteomyelitis requiring debridement.
NATURAL HISTORY
■ Management of bone defects around the knee are a challenging problem that
frequently requires multidisciplinary management between general surgery,
orthopedic surgery, plastic surgery, and infectious disease.
■ Before instituting the described procedure, the surgeon must obtain a clean
bone defect with viable tissue that is free of infection.
■ This may require multiple surgeries focusing on debridement, antibiotic
cement spacer placement, bone stabilization, soft tissue coverage, and
intravenous antibiotics to prepare the area for the described definitive
procedure.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ The patient presentation and reason for the bone defect influence the treatment
approach and time interval to the definitive bone grafting procedure.
■ Trauma and infectious etiologies often require serial debridement and
temporary stabilization with definitive stabilization and soft tissue coverage
performed once a clean tissue bed is achieved.
■ The surgeon should assess the neurovascular status of the involved extremity.
A functional limb is a candidate for limb salvage. A severely compromised
limb may be better with an early amputation.

■ When pursuing limb salvage, the stability of the collateral ligaments should be
tested by applying a varus and valgus stress to a slightly flexed knee.
■ The patient should be asked to extend the knee against gravity to test the
competency of the extensor mechanism.
■ Laboratory studies depend on patient specifics and can be used to assess
nutritional status, blood count recovery after chemotherapy, and inflammatory
markers to assess for infection or response to antibiotics.
IMAGING
■ Radiographs are used to assess defect size and provide an estimate of how
much bone graft will be needed (FIG 1A). Further, the surgeon can plan
implant needs to provide sufficient stabilization of the involved bone.
■ Computed tomography and magnetic resonance imaging (FIG 1B,C) provide
a detailed assessment of cortical bone and offer a volumetric assessment of the
defect.
FIG 1 • A. AP radiograph, (B) coronal T1 MRI, and (C)
coronal T2 MRI of a primary bone tumor of the lateral
proximal tibia.
SURGICAL MANAGEMENT
■ In the setting of a large bone defect (≥6 cm), surgery is generally necessary to
improve function and facilitate weight bearing. The described technique has
been utilized for defects up to 2.5 cm.1
■ The treatment goal is to create a clean and viable tissue bed that is then filled
with a cement spacer to maintain the defect space and induce formation of a
biologically active, vascularized membrane (FIG 2).

■ After 4 to 6 weeks, the cement spacer is removed, and the defect is optimized
for placement of autogenous bone grafting to facilitate reconstitution of the
defect.2
■ The cement spacer provides structural support to the bone, offloads the
implant bridging the defect, maintains the bone void, facilitates formation of
the induced membrane, and can be a conduit for local antibiotic elution.
■ Bone graft is obtained using a reamer-irrigator-aspirator (RIA) system
(Synthes, Paoli, PA).
■ This is a single-pass, negative pressure reaming system for obtaining
intramedullary nonstructural autogenous bone graft.
■ Compared to the traditional iliac crest bone used for the harvest of autogenous
bone graft, RIA obtains more graft volume (on average 60 cc from the femur
and 40 cc from the tibia)3,4, and the graft appears to have equivalent
osteoconductivity and better osteogenicity and osteoinductivity.5–7 Studies also
suggest a greater concentration of stem cells. Harvest of bone graft with RIA is
also less invasive and associated with less donor site morbidity.8
■ Use of RIA to obtain autogenous bone graft is indicated in skeletally mature
patients with normal femur anatomy. Relative contraindications include
metabolic bone disease, presence of metastatic bone cancer in the donor bone,
active osteomyelitis in the donor bone, known bleeding disorder, and
osteoporotic patients with thin cortices.5
■ Bone graft volume can be extended with cancellous allograft and
demineralized bone matrix. Extension is common, and when used, we add
fresh bone marrow aspirate to provide osteogenic mesenchymal stem cells to
the structural allograft.6
■ The induced membrane is a vascularized soft tissue layer that forms around the
cement spacer. It is composed of an outer layer of fibroblasts and collagen and
a synovium-like inner layer. It is rich in growth factors and osteoinductive
elements that include BMP-2. Upon placement of autogenous bone graft, the
membrane prevents graft resorption and facilitates the formation of new
cortical bone.8

FIG 2 • A. Intraoperative preparation of the bone defect.
B. Fluoroscopic view of debridement with high-speed
bur. C,D. Placement of an antibiotic spacer into a
proximal tibia bone defect.
Preoperative Planning
■ Bone reconstruction is a two-stage process.
■ Bone defects from infection or trauma may require serial debridement with
placement of a temporary cement spacer and temporary stabilization of the
bone with an external fixator or long plate. The cement spacer is often loaded
with antibiotics to provide a local elution.
■ A clean defect can be judged by negative cultures, bleeding tissues, and
maintained continuity of the defect with the intramedullary canals.
■ Once clean, the patient is eligible for stage 1 of this procedure.
■ For infection, intravenous antibiotics are generally given for the 4 to 6 weeks
that the cement spacer is implanted. These antibiotics are an adjuvant and do
not make up for an inadequate debridement.9
■ Patients are followed with serial inflammatory markers such as C-reactive
protein (CRP) and erythrocyte sedimentation rate (ESR) to judge eradication of
the infection.
■ At this point, the patient has a clean bone defect that is free of infection.
■ The patient should be counseled on the risks of surgery, which include fracture
of the donor bone, infection of the recipient site, and possible need for blood
transfusion(s).
■ Patients should know that there may be a need to surgically stabilize the donor
femur due to bone perforation by the reamer head or perceived postoperative
fracture risk based on the assessment of cortical thickness after RIA use.
■ Patient should be aware of the donor site location and possible weight-bearing

restrictions after surgery. In general, we try to use a donor bone on the
ipsilateral side of the bone defect in order to maintain one good lower
extremity to aid postoperative rehabilitation.
FIG 3 • A,B. Preoperative radiographs of the donor
femur. The inner diameter of the isthmus is used to
determine the reamer head size needed for bone graft
harvest.
■ Preoperative radiographs are done of the donor femur (FIG 3). The surgeon
assesses cortical thickness, inner cortical diameter at the isthmus, and length of
the femur. This facilitates decision-making on appropriate indications for RIA
use, estimation of reamer head size, and determination of the appropriate
length of the RIA drive shaft (360 or 520 mm).
■ The size of the reamer head is determined by measuring the isthmus of the
donor long bone on both AP and lateral radiographs. A head size 1 to 1.5 mm
larger than the smallest measured inner cortical diameter at the isthmus should
be used. If this measurement is done intraoperatively with fluoroscopy, the
surgeon should factor in the distance of the ruler from the actual bone. The real
canal is larger than the measurement. In general, the canal is 1 mm larger when
the ruler is 2.5 cm away from bone and 2 mm larger when the ruler is 5 cm
away.
■ To use RIA, a power driver with 3.5 to 4.5 Nm of torque and 700 to 900 rpm
should be used. Drills with torque greater than 6 Nm are too powerful and
should not be used.
■ In the operating room, the surgeon will need a radiolucent table, large

fluoroscopy machine, 3-L bags of normal saline, a separate Mayo stand to hold
the RIA, and a source of negative pressure suction.
■ A tourniquet may be used at the bone defect site if brisk bleeding is present
during preparation of the area. Attempts are made to avoid tourniquet use as it
can compromise the assessment of tissue viability.
■ The patient may benefit from a preoperative discussion with the anesthesia
team regarding use of regional or neuraxial anesthesia. This can provide
optimal intraoperative and postoperative pain control.
Positioning
■ Patient position and draping frequently requires coordination between
orthopedic surgery and plastic surgery.
■ Position should facilitate debridement of the bone defect, harvest of bone
graft, and any soft tissue coverage procedures. It may be necessary to change
the patient’s position during the surgery; a repeat sterile prep and drape is then
performed.
■ For bone defects about the knee, a supine position with a bump under the
gluteus is often sufficient.
■ A large C-arm should be placed opposite the side where bone graft will be
harvested. The monitor is positioned at the end of the operating room table.
Approach
■ RIA bone graft harvest from the femur is generally obtained through an
antegrade approach through a greater trochanter start side. This requires an
approximately 3- to 4-cm incision, approximately one hand breath above the
top of the greater trochanter and 2 to 3 cm posterior to the midline axis of the
greater trochanter.
■ Medial and lateral/anterolateral approaches to the distal femur and proximal
tibia for the bone defect are well described in surgical approach textbooks.
T E C H N I Q U E S
■ Induced Membrane With Intramedullary
Autogenous Bone Grafting With Bone Marrow

Aspiration and Intramedullary Nailing
■ Stage 1
Cement Spacer Placement and Internal Fixation
■ For tumors, the patient starts stage 1 at the time of surgical excision of the
malignancy.
■ Stage 1 simply consists of placing a block of cement into a clean bone
defect. The cement is hand mixed in a bowel and allowed to reach a doughy
consistency. The goal is to maintain the defect space while avoiding the
interdigitation of cement into the bone, which would make removal difficult
(TECH FIG 1).
■ It is important to overlap the bone ends with cement to induce a
pseudomembrane longer than the defect itself.
■ In the absence of infection, definitive internal fixation can be placed at this
time. When possible, we prefer a titanium intramedullary nail to maintain the
canal, facilitate early weight bearing, and prevent future central necrosis of
the autogenous bone graft.
■ Intramedullary implants can be placed antegrade or retrograde in the femur
and antegrade in the tibia. New implants allow for fixation in short bone
segments.
■ In defects close to the joint, a strong 4.5-mm periarticular plate with fixed-
angle locking screws into the short segment is most often used.
TECH FIG 1 • Placement of cement spacer into defect

to generate an induced membrane.
■ In the setting of infection, it is best to avoid metal implants altogether and
rely on splints. Sometimes it is necessary to place antibiotic intramedullary
nails or bridge plates coated in antibiotic cement for adequate bone
stabilization.
Soft Tissue Coverage and Monitoring
■ If soft tissue coverage is needed, it is done after placement of the cement
block spacer. Defects in the proximal tibia are often augmented with a medial
gastrocnemius flap (TECH FIG 2).
■ If soft tissue coverage is not an urgent concern, muscle flap coverage can
also be done at the time of definitive bone grafting.
■ The patient is monitored for the next 4 to 6 weeks.
■ Weight bearing on the affected lower extremity is dictated by the strength
of the cement/implant construct. At a minimum, the construct must provide
enough stability to allow knee range of motion.
■ Patients with infection have periodic checks of inflammatory markers.
■ At the end of intravenous antibiotics, these patients are followed for an
additional 2 to 3 weeks off antibiotics to monitor for any signs of recurrent
infection before proceeding with stage 2 of this procedure.

TECH FIG 2 • A,B. Medial gastrocnemius rotational
flap of a proximal tibia bone defect.
■ Stage 2
Spacer Removal and Bone Preparation
■ The second stage begins by accessing the bone defect through the prior
surgical incision.
■ Patient positioning should allow access to the bone defect and the hip
selected for RIA bone graft harvest.
■ When exposing the bone defect site, it is very important to carefully incise
the induced membrane longitudinally and use a Cobb or periosteal elevator to
isolate the membrane off of the cement spacer.
■ The spacer often needs to be fractured with an osteotome and removed
piecemeal.

■ Bone ends are gently debrided of any fibrous tissue, and if no intramedullary
implant, the intramedullary canals are accessed with a flexible reamer or
high-speed bur to assure continuity.
■ With infection, the surgeon should maintain a high level of suspicion for
persistent infection.
■ Intraoperative frozen section for high-powered fields can be done for an
objective measure of continued infection.
■ In general, a finding of more than 5 to 10 WBC/HPF warrants
consideration for irrigation and debridement with another 6-week cycle of
cement spacer and intravenous antibiotics.
■ When the bone defect site is clean with a nice induced membrane (TECH
FIG 3), attention is turned to the intramedullary harvest of autogenous bone
graft using RIA.
Inserting the Guidewire
■ A large C-arm fluoroscopy positioned on the opposite side of the patient is
used to localize the top of the greater trochanter.
TECH FIG 3 • Clean bone defect after removal of the
cement spacer. The defect is contained by the
induced membrane.
■ A 3- to 4-cm incision is made approximately 5 cm proximal and 2 cm
posterior to the midline of the greater trochanter.
■ A 3.2-mm guide pin is positioned at the tip of the greater trochanter on AP
fluoroscopy and in the midline of the greater trochanter on the lateral view.
The guide pin should aim for the center of the intramedullary canal at the

level of the lesser trochanter (TECH FIG 4).
■ Once the guide pin is driven 5 to 6 cm into the bone and the position
confirmed on fluoroscopy, the skin and deep fascia are incised with a scalpel
around the guide pin to cannulate the guide pin with a soft tissue protector.
■ A 12-mm cannulated reamer is used through a soft tissue protector to drill 3
to 4 cm into the greater trochanter to create a start site.
■ The power source should be set to “drill,” and the surgeon should allow the
drill to spin at full speed before contacting greater trochanter bone. This
will create a clean entry site.
■ Limited entry into the bone will allow more bone to be harvested.
TECH FIG 4 • Illustration of the antegrade start site for
RIA bone graft harvest. The guide pin is placed in-line
with the center of the femoral canal.
■ A 2.5 mm diameter, 950 mm in length, ball-tipped guidewire is placed
through the greater trochanter start site and inserted down the intramedullary
canal of the femur to roughly 2 to 3 cm above the physeal scar of the distal
femur.
■ AP and lateral fluoroscopy is undertaken to assure the guidewire is within

the intramedullary canal.
■ A T-chuck handle may be placed onto the guidewire and gently tapped with
a mallet to aid the guidewire passing through the metaphyseal bone of the
proximal femur.
■ A slight bend is often required in the distal aspect of the guidewire to direct
the guidewire into a center-center position in the distal femur.
■ This helps avoid eccentric reaming and minimizes the risk of cortical
perforation by the sharp reamer head.
■ Measure the length of the guidewire within the femur to select the proper
length of the RIA drive shaft. Length options are 360 and 520 mm.
Preparing the RIA
■ The RIA system comes with a ruler that overlay the patient’s skin (TECH
FIG 5A).
■ With intraoperative fluoroscopy, the inner isthmic diameter of the femur in
both AP and lateral planes can be measured to determine the size of the
reamer head needed to obtain the necessary volume of bone graft.
■ The intramedullary canal is often elliptical, and one measure will be
smaller than the other.
■ A reamer head that is 1 to 1.5 mm larger than the smallest isthmic diameter
is recommended.
■ Reamer heads are available in 12 to 19 mm diameters.
■ As noted earlier, measurement of the isthmus at the skin level by
intraoperative fluoroscopy requires a correction for magnification. The actual
size of the isthmus is larger than the measurement. This is important when
selecting the size of the reamer head.
■ On a separate Mayo stand, the RIA device is assembled according to
manufacturer specifications (TECH FIG 5B).
■ The reamer head is front-end cutting and sharp. The surgeon should assure
several things: that the reamer head is mated correctly with the drive shaft,
that the rubber seal is placed over the proximal drive shaft before it is
connected to the power source, and that the plastic casing protecting the
rotating connection between the power source and the drive shaft is locked
into place.
■ Connect irrigation to RIA, it is the most proximal, smaller port labeled “I.”
■ Connect suction to RIA. It is the most distal, larger port labeled “A.”
■ Attach the 100-cc filter to the suction (“A” port). This has a particulate

filter of 500 μm to capture the viscous autogenous bone graft.
■ Place the power source on the “drill” setting during reaming to allow for
high speed and low torque.
■ A 3-L bag of normal saline should be placed 3 ft. or higher above the RIA
device to allow adequate gravity flow. The suction tubing should be attached
to a closed, continuous suction canister with a large reservoir.
TECH FIG 5 • A. Intraoperative measurement of the
femur isthmus using fluoroscopy. B. The reamer-
irrigator-aspirator (RIA) device. The ports for fluid
inflow and outflow are labeled. The aspiration port
connects to a filter that captures the intramedullary
bone graft.
Reaming the Graft Material
■ Test the RIA device on the Mayo stand outside of the patient by starting the
irrigation and suction. Activate the power source to assure the reamer tip is
properly revolving.
■ The RIA system is single pass and continuously irrigates and suctions within
the intramedullary canal. This decreases intramedullary temperatures and
decreases viscosity of the graft.
■ Place the RIA system over the guidewire. Before entering the patient, verify
flow of irrigation. Insert the device through the soft tissue protection sleeve
and turn on suction when the reamer head is set into the insertion site at the
greater trochanter.
■ Before starting, warn anesthesia about possible blood loss due to the
negative pressure suction.
■ The power source should be fully activated.
■ RIA is propagated through an advance-withdraw technique every 2 to 3 cm

to avoid clogging of the aspiration tubing by particulate graft (TECH FIG
6A).
■ The surgeon should move slowly through the isthmus to allow time for
appropriate emulsification of the graft (TECH FIG 6B). It is important not
to forcibly push through resistance as incarceration of the reamer head or
clogging of the aspiration tubing may occur.
■ Fluoroscopy should be used liberally during active reaming to monitor the
position of the reamer head.
■ The surgeon should continually assess for eccentric reaming, which most
commonly takes place in the medial proximal femur and distal anterior
femur.
■ It bears repeating that the surgeon must take great care to avoid
incarceration of the reamer head at the isthmus and perforation of the
anterior cortex as well as the knee joint distally.
■ When reaming distally in the femur, a lateral fluoroscopic view is
recommended to assess for perforation of the anterior femoral cortex.
■ Aspiration tubing should be periodically checked to assure flow of bone
graft and to assure the line is not clogged.
■ When actively reaming, both irrigation and suction should be turned on.
When reaming is paused, both lines should be stopped to avoid excessive
blood loss.
■ To obtain more graft volume, the surgeon can rotate the guidewire to capture
the metaphyseal bone in the medial and lateral aspects of the distal femur.
■ The RIA system should continue to be fully activated while withdrawing the
drive shaft from the femur. If this is difficult, the surgeon can reverse the
direction of the reamer head to facilitate removal.

TECH FIG 6 • A. Use of intraoperative fluoroscopy to
follow the reamer head during RIA bone graft harvest.
It is important to assure that the sharp reamer head
remains central in the intramedullary canal. B.
Appearance of RIA autogenous bone graft after
harvest.
Completion of Reaming
■ When the reamer tip is back at the top of the greater trochanter, turn off
suction and irrigation. The device is removed.
■ Pack the proximal femur skin incision with gauze or a hemostatic agent.
■ View the collection canister, which has markings on the outside to estimate
the volume of graft obtained.
■ If more graft is needed, upsize the reamer head by 0.5 to 1 mm and perform
another pass down the femur. Generally, one to two passes are sufficient.
■ Once graft volume is adequate, disconnect the collection canister, and move
it over the sterile operating room table.
■ Remove the lid, and use a plunger to compress the graft.
■ Invert the filter with the plunger in place to remove the inner filter. Turn the
inner filter vertical, and use the plunger to remove the graft into a sterile
basin.
Harvesting Bone Marrow
■ Fresh bone marrow is then obtained by palpating the medius pillar of the
ilium.
■ Thumb pressure can be used to push soft tissues toward the abdomen to feel
the thickness of the pillar.
■ A small skin puncture with a no. 11 blade scalpel is made over the medius
pillar.
■ A disposable 14-gauge T-handle bone marrow biopsy needle is introduced.
Tactile feel is used to center over the medius pillar bone (TECH FIG 7).
■ Gentle, sustained pressure is applied with a back and forth rotation to
puncture the bone and gain access to the marrow space between the inner and
outer shelves of the ilium. The needle is generally inserted around 3 cm.
■ The top of the T-handle is rotated 90 degrees to remove the stylet. A 12- or

20-mL syringe is engaged to the Luer-lock to aspirate bone marrow. The
amount of bone marrow needed is proportional to the size of the defect. The
goal is to saturate the final volume of bone graft.
■ The syringe of bone marrow aspirate is disconnected, and the needle is
withdrawn. Pressure is applied to the puncture site for 5 to 10 minutes, and a
Steri-Strip is placed over the puncture site.
Graft Placement
■ The autogenous intramedullary bone graft and bone marrow aspirate are
mixed together in a sterile basin.
■ The graft is extended with 1- to 4-mm cancellous allograft and
demineralized bone matrix to create an appropriate graft consistency and to
achieve adequate volume. The goal consistency is equivalent to gritty
toothpaste.
■ The recipient bone defect undergoes a final low-pressure irrigation.
■ The bone graft mixture is packed into the defect with thumb pressure. Avoid
dense packing of the graft with instruments such as a bone tamp.
■ Highly compacted graft does not incorporate as well (TECH FIG 8A–D).
■ Suture the induced membrane closed (Video 1). This should completely
cover the graft as it prevents resorption and promotes the formation of the
cortical bone.
Video p7-c031
■ All surgical sites should be closed in layers. Suture for skin closure is at the
discretion of the surgeon (TECH FIG 8E).
00:00 / 00:00

■ Sterile dressings are applied.
TECH FIG 7 • A. Bone marrow biopsy needle insertion
site in the medius pillar of the pelvis. B. The needle is
gently twisted back and forth as it is inserted.
TECH FIG 8 • A,B. The bone defect is filled with bone
graft with fresh bone marrow aspirate. The graft
completely fills the defect, but impaction of the graft is

avoided. In a different patient, (C) intraoperative AP
and (D) lateral fluoroscopic views of the proximal tibia
filled with autogenous bone graft and stabilized with a
lateral plate. E. Skin closure after RIA bone grafting
and stabilization into a defect with an induced
membrane.
PEARLS AND PITFALLS
Bone
graft
harvest
■ Try to harvest RIA from the femur ipsilateral to the bone defect. This
maintains an unaffected lower extremity to facilitate postoperative
rehabilitation.
■ While using RIA, keep the filter for the bone graft in a vertical position
to avoid over washing and loss of growth factors.
■ When finished with RIA, disconnect the irrigation and aspiration tubing
to avoid unsterile tubing coming up to the sterile field and causing
contamination.
Union
■ Central graft often remains avascular; the use of a nail or resorbable
mesh to maintain the native intramedullary canal helps limit graft
volume and improves the formation of cortical bone8.
■ Bone stabilization with an intramedullary implant is preferred as this
preserves the native medullary canal and helps to prevent the lack of
incorporation seen in central graft in larger bone defects8. This is not
always possible, however, and plate fixation may be necessary based on
the defect itself (FIG 4).
Fracture
■ Consider restricted weight bearing or placement of a prophylactic
intramedullary nail after RIA use. Especially if the donor bone has
narrow cortices or the patient is osteopenic or osteoporotic.3
■ Consider use of iliac crest bone grafting in osteoporotic patients.
■ Fluoroscopy in orthogonal planes is useful to assure a proper start site
for RIA harvest and to assess cortical thickness of the femur after RIA
use.
■ A greater trochanter start site for RIA harvest minimizes the reamer
entry angle and decreases the risk of postoperative femoral neck
fracture.

■ Reaming ≥ 2 mm of the inner diameter of the femoral isthmus decreases
the torsional strength of the femur.
■ It is important to place the guidewire for RIA bone graft harvest in the
center of the intramedullary canal to avoid eccentric reaming of the
femoral cortex.
Blood
loss
■ RIA suction can lead to rapid blood loss. It is important to communicate
this to anesthesia.
■ Patients should be typed and crossed before starting the procedure.
■ Stop RIA suction when not actively reaming.5
■ Pack the hip incision at the conclusion of RIA use to avoid a gluteal
hematoma.
RIA
irrigation
water
■ Filtrate water contains viable cells including mesenchymal stem cells.10
■ Adding filtrate to the harvested bone graft may improve incorporation
and corticalization.
POSTOPERATIVE CARE
■ Weight-bearing restrictions for the bone defect are advised. The length of time
depends on the size of the bone defect, implant use, graft harvest technique,
and patient bone stock. Implementation is at the discretion of the surgeon and
is determined on a case-by-case basis.
■ Restrictions for the bone graft harvest site are generally advised if multiple
RIA passes are performed or thin femoral cortices are noted at the end of the
procedure.
■ A knee immobilizer is often used for 2 weeks to facilitate soft tissue healing.
Physical therapy is then started to work on knee joint range of motion.
■ First radiographs are done 6 weeks from surgery (FIG 5). Serial radiographs
are used to assess the incorporation of bone graft.
■ Bone defects stabilized with an intramedullary implant can often start partial
progressive weight bearing at 3 to 4 months after surgery.
■ Computed tomography can be used to further investigate bone graft
incorporation and determine the necessity of additional bone grafting
procedures.

FIG 4 • Fluoroscopic image showing stabilization of a
proximal femur bone defect with a 4.5-mm periarticular
plate. The small amount of residual bone at the joint
level did not allow for an intramedullary implant.
OUTCOMES
■ Union of a bone defect after autogenous bone grafting appears to be
independent of defect length.11 Defects up to 25 cm have been addressed with
this technique (Norris).
■ Radiographic healing is often seen by 4 months.
■ Approximately 70% of defects heal by 6 months and 80% heal by 1 year.1
FIG 5 • A. AP and (B) lateral radiographs of the bone
defect after definitive bone grafting with autogenous,
intramedullary bone graft with graft extension and fresh

bone marrow aspirate.
■ Approximately 50% of patients heal with just one bone grafting procedure,
35% heal with more than one bone grafting procedure (McCall).
■ Long-term donor site morbidity is less with RIA harvest compared to iliac
crest bone graft harvest.4,12
COMPLICATIONS
■ The complication rate with RIA harvest is 1.96% to 6.2%.3,4
■ Iatrogenic fracture of the femur from RIA harvest is the most common
complication, and it is related to technical aspects of the procedure including
poor start site, eccentric reaming, and over-reaming.
■ After RIA harvest, the femur is weakest in torsion.
■ Femoral shaft fracture, femoral neck fracture, and anterior cortical perforation
of the femur are described complications with RIA harvest.
■ Heterotopic ossification of the abductors can be seen at the RIA start site and
is generally asymptomatic.
■ Problems encountered at the bone defect site include deep infection, nonunion,
and implant loosening/failure.
■ Nonunion rate is approximately 15%; causative factors include inadequate
graft volume, suboptimal graft placement, and infection.8
REFERENCES
1. Stafford PR, Norris BL. Reamer-irrigator-aspirator bone graft and bi
Masquelet technique for segmental bone defect nonunions: a review of 25
cases. Injury. 2010;S2:S72-S77.
2. Pelissier P, Masquelet A, Lepreux S, et al. Behavior of cancellous bong graft
placed in induced membranes. Br J Plast Surg. 2002;55: 598-600.
3. Lowe JA, Della Rocca GJ, Murtha Y, et al. Complications associated with
negative pressure reaming for harvesting autologous bone graft: a case series. J
Orthop Trauma. 2010;24:46-52.
4. Qvick LM, Ritter CA, Mutty CE, et al. Donor site morbidity with reamer-
irrigator-aspirator (RIA) use for autogenous bone graft harvesting in single
centre 204 case series. Injury. 2013;44: 1263-1269.
5. Giannoudis PV, Tzioupis C, Green J. Surgical techniques: how I do it? The
reamer/irrigator/aspirator (RIA) system. Injury. 2009;40: 1231-1236.
6. Nauth A, Lane J, Watson JT, et al. Bone graft substitution and augmentation. J

Orthop Trauma. 2015;29:S34-S38.
7. Schmidmaier G, Herrmann S, Green J, et al. Quantitative assessment of
growth factors in reaming aspirate, iliac crest, and platelet preparation. Bone.
2006;38:1156-1163.
8. McCall T, Brokaw D, Jelen B, et al. Treatment of large segmental bone
defects with reamer-irrigator-aspirator bone graft: technique and case series.
Orthop Clin North Am. 2010;41:63-73.
9. Apard T, Bigorre N, Cronier P, et al. Two-stage reconstruction of post-
traumatic segmental tibia bone loss with nailing. Orthop Traumatol Surg Res.
2010;96:549-553.
10. Cox G, Jones E, McGonagle D, et al. Reamer-irrigator-aspirator Indications
and Clinical Results: a systematic review. Int Orthop. 2011;35:951-956.
11. Myeroff C, Archdeacon M. Current concepts review. Autogenous bone graft:
donor sites and techniques. J Bone Joint Surg Am. 2011;93:2227-2236.
12. Belthur M, Conway J, Jindal G, et al. Bone graft harvest using a new
intramedullary system. Clin Orthop Relat Res. 2008;466: 2973-2980.

32
CHAPTER
Soft Tissue Coverage of the
Knee: Gastrocnemius
Muscle Flap
Hani Sbitany
DEFINITION
■ Soft tissue defects around the knee, or the anterior third of the tibia, often
cannot be treated with local fasciocutaneous flaps; instead, the most reliable
local/regional coverage option is the rotational gastrocnemius muscle flap.1
■ This is taken as a pure muscle flap, and in defects that include skin loss, the
muscle is immediately skin grafted.
■ This rotational muscle flap is well perfused, given its axial blood supply, and
provides excellent soft tissue coverage and reliable reconstruction of defects
involving the underlying bone, tendon, or exposed surgical hardware.2
ANATOMY
■ The gastrocnemius is a bipennate muscle, located in the superficial posterior
compartment of the lower extremity.
■ Other muscles in this compartment include the soleus muscle and plantaris
muscle.
■ These muscles come together, via their common insertion in the posterior
surface of the calcaneus, to create the Achilles tendon.
■ These muscles act to cause flexion of the ankle, when the knee is extended.
■ The gastrocnemius muscle is the most superficial of these muscles, situated
just deep to the posterior calf skin and subcutaneous tissue, and consists of a
medial and lateral muscle head.
■ The blood supply to these gastrocnemius muscles comes from the sural artery
and vein, which are direct branches from the popliteal vessels; the motor nerve
innervation derives from the tibial nerve.

■ The medial and lateral heads of the gastrocnemius muscles can be separated
from each other at their midline confluence, and each muscle belly can be
isolated on its medial or lateral sural vessel pedicle, respectively.
■ The medial head of the gastrocnemius muscle is usually longer and wider than
the lateral head and thus has a greater arc of rotation and reach as a rotational
flap; for this reason, the medial head is most commonly harvested for proximal
lower extremity reconstruction.3
■ Because the Achilles tendon is made up of contribution from all four muscles
in the superficial posterior compartment, the ankle can still safely flex
following harvest of one belly of the gastrocnemius muscle.
PATHOGENESIS
■ As stated, the gastrocnemius rotational muscle flap is most commonly used for
soft tissue reconstruction of defects situation around the knee or the proximal
third of the tibia.
■ There are many possible causes of defects in this region:
■ Traumatic wounds
■ Oncologic resection wounds
■ Soft tissue infection/necrotizing fasciitis
■ Burn, or burn contracture release, wounds
■ Breakdown of surgical wound after total knee arthroplasty
• These wounds often contain exposed surgical hardware.
■ Breakdown of wound following patella or patellar tendon repair
PATIENT HISTORY AND PHYSICAL FINDINGS
■ The cause and chronicity of the soft tissue wound in this area must be carefully
defined.
■ The patient must be questioned for a history of prior lower extremity surgery
or injury along the entire limb that may have altered soft tissue anatomy or
neurovascular supply.
■ The specific wound location and size must be recorded and examined carefully
to ensure that a rotational gastrocnemius muscle flap will adequately reach this
wound with minimal tension.4
■ With the patient contracting the calf muscles, and flexing the ankle, the distal
portion of the gastrocnemius muscle belly can be visualized or palpated, and
this is the point that should be used in assessing muscle flap reach.
■ If this is not the case, then free tissue transfer must be considered.

■ Physical examination of the knee and ankle must be performed, with range of
motion being carefully assessed.
■ Range of motion at the knee (normal 135 degrees) must be defined, along
with confirmation of normal flexion in all positions.
■ Range of motion at the ankle (normal 70 degrees) must be defined, along
with normal flexion with the knee extended.
■ If exam reveals normal findings, then rotational medial or lateral
gastrocnemius muscle flap is safe.
IMAGING
■ Routine imaging of the lower extremity is not necessary prior to
gastrocnemius rotational muscle flap.
■ If the patient has a history of peripheral vascular disease, a preoperative
angiogram or CT angiogram can be obtained, to assess patency of popliteal and
sural arteries.
■ If the patient has a history of deep vein thrombosis, or venous insufficiency,
then lower extremity venogram can be performed.
SURGICAL MANAGEMENT
Preoperative Planning
■ Once the gastrocnemius muscle flap has been chosen as the reconstructive
option, the surgeon must determine location of the muscle flap donor incision.
■ In most cases, for knee defects (anterior, lateral, or medial knee), the muscle
harvest incision is separate from the wound being reconstructed, and the
muscle is tunneled underneath the intervening skin bridge.
■ For wounds over the proximal third of the anterior tibia, it is common to
extend the harvest incision from the defect, so that they are in continuity.
Positioning
■ The patient is most commonly placed in a supine position on the operative
table.
■ In some cases, based on wound location and dimensions, it is easier to
harvest with the patient in a lateral decubitus position, and this is also
acceptable.
■ When the patient is supine, the entire lower extremity should be
circumferentially prepped into the operative field, such that the leg can be