Operative Technique in Plastic Surgery – Kevin C.Chung

■ Wide exposure of the field and ensuring a conducive atmosphere are critical
for successful microvascular anastomosis.
■ End-to-side anastomosis of the artery is preferred to maintain vascular flow
in inherent arteries of the leg and to avoid iatrogenic ischemic complications
of the leg.
■ The deep vein system (comitantes vein) is usually given the first
consideration because of the special convenience with dissection and inset.
However, the superficial veins (long saphenous and short saphenous veins)
can be used when there is significant size mismatch with the deep veins or if
no adequate deep vein is suitable. Regardless of the use of the deep or
superficial veins, the quality of the recipient vein should be checked based on
intraoperative findings such as the absence of scarring around the vein,
existence of backflow, absence of thrombi, and absence of resistance to an
intraluminal heparinized saline flush.15
■ The vascular clamp is removed after completion of the anastomosis. Warm
saline is irrigated onto the vessels and flap, followed by waiting for several
minutes to check patent inflow and outflow of the flap.
■ Meticulous hemostasis is performed under the microscope to ensure that
branches of the pedicle and recipient vessels are secured as hematoma is
known to be one of the main causes of re-exploration after free flap
reconstruction in lower extremities.12
TECH FIG 4 • A. Temporary inset of the flap for
microvascular anastomosis. B. After completion of
microvascular anastomosis. End-to-side anastomosis
of the artery and end-to-end anastomosis of the vein
were carried out.

■ Final Inset
■ If a flap is too bulky, then meticulous defatting of the perforator flap can be
performed at the time of insetting. The deep fat, superficial fascia, and deep
layer of superficial fat can be safely removed, but not the area near the
perforators (about 2–3 cm diameter), using scissors with or without loupe but
microscope magnification is not usually necessary (TECH FIG 5A). This is a
crucial procedure for obtaining a satisfactory contour of the reconstructed
lower leg. However, to completely avoid tissue damage within the flap and
risk of ischemic complication at the initial operation, secondary procedure for
thinning is an alternative option.
■ The final inset of the flap needs to be carefully performed because the
pliability and extensibility of the flap may change after the defatting
procedure.16 Excessive flap tissue is diligently excised to yield a more natural
appearance (TECH FIG 5B,C).
■ The wound is closed by placing drains under the flap to prevent fluid
collection.
■ A leg splint is frequently applied for immobilization. An elastic bandage is
loosely applied. Part of the flap is left open for postoperative monitoring of
the flap (TECH FIG 5D). Excessive compression over the vascular pedicle
should be avoided.

TECH FIG 5 • A. Defatting of the perforator flap. B,C.
Immediate postoperative photos. D. Dressings of the
reconstruction site.
PEARLS AND PITFALLS
Planning
■ Elaborate preoperative planning of recipient vessels, donor
site, flap composition, and positioning of the patient is
important for successful reconstruction.
■ A multidisciplinary approach including comprehensive
communication with the oncologist and/or orthopedic
surgeon will allow better treatment outcomes.
Flap design
■ The exact template created according to the final defect size
and shape is helpful to avoid harvesting an unnecessarily
large flap and to obtain an aesthetically pleasing contour of
the lower leg.
Placement of the
pedicle
■ It is important to avoid twisting of the vascular pedicle.
■ If the pedicle is excessively long, it is placed in a lazy-S–
shaped position under the flap to avoid kinking of the

pedicle.
■ Minimize tension on the pedicle. Sufficient acquisition of the
pedicle can be a safe strategy.
Microanastomosis
■ End-to-side anastomosis of the artery is preferred to maintain
distal vascular flow in named arteries of the lower leg and to
avoid potential ischemic sequelae of the leg.
■ The deep vein system (venae comitantes) is usually given the
first consideration as a source of outflow because of special
convenience for dissection and inset and because it is less
vulnerable to trauma than the superficial venous system.
Flap inset
■ Defatting of the perforator flap is a valuable technique for
obtaining an aesthetic contour at the time of inset, but must
be done meticulously to avoid compromising perfusion.
■ Dimensional excess of the flap is diligently corrected by
careful trimming.
Hemostasis
■ Meticulous hemostasis needs to be performed during the
entire surgical procedure because hematoma is known to be
one of the main causes of re-exploration after free flap
reconstruction in lower extremities.
POSTOPERATIVE CARE
■ Proper patient positioning and avoidance of vascular pedicle compression (by
splinting or inattentive wound dressings) play vital roles in the postoperative
period.
■ The leg is elevated for better venous return and to minimize edema while the
patient is lying in bed.
■ There is no consensus regarding the use of medications for
thromboprophylaxis, such as aspirin, heparin, and dextran. The authors do not
routinely use any of these medications.
■ Enoxaparin (low molecular weight heparin) is considered for deep vein
thrombosis prophylaxis in lower extremity reconstructions as
chemoprophylaxis is recommended for general surgery patients scoring 3 or
higher on the Caprini scale.17 Patients undergoing lower extremity
reconstruction with free flap frequently fall into the high-risk group with
Caprini scores of 5 or greater.18
■ Postoperatively the flap can be monitored every 1 to 3 hours for the first 48
hours, and every 4 to 6 hours for the next 48 hours after the surgery.
Monitoring is typically performed by physical examination and handheld

pencil Doppler.
■ An oral diet is allowed 24 hours after surgery.
■ Although the duration of immobilization time varies based on the orthopedic
and bony injuries, generally progressive weight bearing and ambulation are
achieved once the flap maturation is assured, which occurs in 2 to 3 weeks for
isolated soft tissue reconstruction.
OUTCOMES
■ Microvascular free flap for lower extremity reconstruction is currently a safe
and reliable procedure with a high success rate. Recent advancements in
technology and improvement in surgical techniques have led to reported
success rates of between 94% and 100%.5,8,12,19
■ Microvascular free flap is a reliable reconstructive option for defects of
various sizes in various locations of the lower leg, and multiple tissue
components such as cutaneous, muscle, and muscle chimeric can be used
according to tissue requirements (FIG 9).
FIG 9 • Cases of lower leg reconstruction with free
flaps. A. Dual-pedicled deep inferior epigastric artery

perforator (DIEP) flap for extensive lower leg defect.
Dual pedicles were anastomosed to the posterior tibial
artery and vein with the end-to-side method. B.
Reconstruction of small defect with TDAP flap. Anterior
tibial vessels were used as recipient vessel. C.
Reconstruction of extensive defects on the proximal
lower leg using the DIEP flap. Medial sural vessels
were used for recipient vessels, and the great
saphenous vein was used for superdrainage. D.
Reconstruction of the distal lower leg using the TDAP
flap. Anterior tibial vessels were used as recipient
vessels. E. Free muscle (latissimus dorsi) flap with skin
graft. F. Muscle chimeric TDAP flap for distal lower leg
reconstruction.
COMPLICATIONS
■ Vascular-related complications such as venous and arterial thrombosis
■ Hematoma: Early diagnosis of a hematoma under the flap is critical so that it
can be evacuated promptly to prevent the compression and obstruction of the
anastomotic site from the expanding hematoma. In particular, any time a
postoperative hematoma is noted, the surgeon must consider venous
thrombosis.
■ Infection
■ Partial flap necrosis
REFERENCES
1. Haddock N, Garfein ES, Reformat D, et al. Perforator vessel recipient options
in the lower extremity: an anatomically based approach to safer limb salvage. J
Reconstr Microsurg. 2010;26:461-469.
2. Tashiro K, Harima M, Yamamoto T, et al. Locating recipient perforators for
perforator-to-perforator anastomosis using color Doppler ultrasonography. J
Plast Reconstr Aesthet Surg. 2014;67:1680-1683.
3. Gao SH, Feng SM, Chen C, et al. A new recipient artery for reconstruction of
soft-tissue defects in the lower limb with a free anterolateral thigh flap: the
reversed descending branch of the lateral femoral circumflex artery. Plast

Reconstr Surg. 2012;130:1059-1065.
4. Suh HS, Lee JS, Hong JP. Consideration in lower extremity reconstruction
following oncologic surgery: patient selection, surgical techniques, and
outcomes. J Surg Oncol. 2016;113:955-961.
5. Duymaz A, Karabekmez FE, Vrtiska TJ, et al. Free tissue transfer for lower
extremity reconstruction: a study of the role of computed angiography in the
planning of free tissue transfer in the posttraumatic setting. Plast Reconstr
Surg. 2009;124:523-529.
6. Lee KT, Wiraatmadja ES, Mun GH. Free latissimus dorsi muscle-chimeric
thoracodorsal artery perforator flaps for reconstruction of complicated defects:
does muscle still have a place in the domain of perforator flaps? Ann Plast
Surg. 2015;74:565-572.
7. Calderon W, Chang N, Mathes SJ. Comparison of the effect of bacterial
inoculation in musculocutaneous and fasciocutaneous flaps. Plast Reconstr
Surg. 1986;77:785-794.
8. Hong JP, Shin HW, Kim JJ, et al. The use of anterolateral thigh perforator
flaps in chronic osteomyelitis of the lower extremity. Plast Reconstr Surg.
2005;115:142-147.
9. Rodriguez ED, Bluebond-Langner R, Copeland C, et al. Functional outcomes
of posttraumatic lower limb salvage: a pilot study of anterolateral thigh
perforator flaps versus muscle flaps. J Trauma. 2009;66:1311-1314.
10. Medina ND, Kovach SJ III, Levin LS. An evidence-based approach to lower
extremity acute trauma. Plast Reconstr Surg. 2011;127: 926-931.
11. Soltanian H, Garcia RM, Hollenbeck ST. Current concepts in lower extremity
reconstruction. Plast Reconstr Surg. 2015;136: 815e-829e.
12. Basheer MH, Wilson SM, Lewis H, Herbert K. Microvascular free tissue
transfer in reconstruction of the lower limb. J Plast Reconstr Aesthet Surg.
2008;61:525-528.
13. Hallock GG. Medial sural artery perforator free flap: legitimate use as a
solution for the ipsilateral distal lower extremity defect. J Reconstr Microsurg.
2014;30:187-192.
14. Hwang JH, Lim SY, Pyon JK, et al. Reliable harvesting of a large
thoracodorsal artery perforator flap with emphasis on perforator number and
spacing. Plast Reconstr Surg. 2011;128:140e-50e.
15. Lorenzo AR, Lin C-H, Lin C-H, et al. Selection of the recipient vein in
microvascular flap reconstruction of the lower extremity: Analysis of 362 free-
tissue transfers. J Plast Reconstr Aesthet Surg. 2011;64: 649-655.

16. Jeon BJ, Lim SY, Pyon JK, et al. Secondary extremity reconstruction with
free perforator flaps for aesthetic purposes. J Plast Reconstr Aesthet Surg.
2011;64:1483-1489.
17. Gould MK, Garcia DA, Wren SM, et al. Prevention of VTE in nonorthopedic
surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th
ed: American College of Chest Physicians Evidence-Based Clinical Practice
Guidelines. Chest. 2012;141:e227S-e277S. doi:210.1378/chest.1311-2297.
18. Kim SY, Lee KT, Mun GH. Postoperative venous insufficiency in
microsurgical lower extremity reconstruction and deep vein thrombosis
potential as assessed by a Caprini risk assessment model. Plast Reconstr Surg.
2015;136:1094-1102.
19. Wettstein R, Schurch R, Banic A, et al. Review of 197 consecutive free flap
reconstructions in the lower extremity. J Plast Reconstr Aesthet Surg.
2008;61:772-776.

26
CHAPTER
Soft Tissue Coverage of
Lower Leg—Soleus Flap
Rahim Nazerali and Lee L. Q. Pu
DEFINITION
■ Mathes and Nahai type II muscle
■ Most commonly proximally based pedicled flap, but a distally based flap has
been reported.
ANATOMY
■ Broad, large, bipennate muscle
■ Deep to the gastrocnemius muscle in the posterior compartment of the leg
■ Occupies major portion of superficial posterior compartment of the leg in the
middle third tibial level
■ Two separate muscle bellies, medial and lateral with separate origins
■ Origin
• Lateral belly: posterior surface of the fibula
• Medial belly: middle third of the medial border of the tibia
■ Insertion
• Lateral belly: dorsal lateral aspect of the Achilles tendon
• Medial belly: dorsal medial aspect of the Achilles tendon
■ Vascular supply (FIG 1)
■ Proximal portion of muscle receives independent axial vascular supply to its
medial and lateral bellies.
■ Dominant pedicle: muscular branches of the popliteal artery and from
proximal two branches of the posterior tibial artery and peroneal artery
■ Distal portion of muscle primarily receives segmental blood supply from two
to four segmental branches from the posterior tibial artery.

■ Innervation
■ Motor: posterior tibial and medial popliteal nerves
■ Function
■ Plantar flexion
FIG 1 • A schematic diagram shows the vascular
anatomy of a soleus muscle.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Just like any other major flap surgery for the lower extremity, a patient’s

general medical condition and neurovascular physical examination should be
evaluated carefully.
■ Previous orthopedic trauma to the leg and ongoing orthopedic procedures
should also be taken into a consideration when planning a soleus muscle flap.
IMAGING
■ Preoperative angiogram is recommended if using a distally based medial
hemisoleus muscle flap to assess the blood supply, which is typically from
branches of the posterior tibial vessels.
SURGICAL MANAGEMENT1-7
■ Soleus is the standard muscle flap of choice for middle third defects of the leg.
■ Numerous limitations with bulk, arc of rotation and weakening of plantar
flexion when using the entire muscle.
■ Medial hemisoleus muscle flap can be elevated based either proximally or
distally depending on the location of the soft tissue reconstruction required.
■ Medial hemisoleus muscle flaps should be chosen to reconstruct a less
extensive wound (less than 50 cm2 in most adult patients).
■ Proximally based flaps can be used to cover middle third tibial wounds in the
leg, whereas distally based flaps can be used for distal third defects. In
addition, proximally based flaps can also be used to cover distal third defects if
done properly.
Preoperative Planning
■ Physical exam including pulse, neurological status, tissue quality
■ Ensure that the soleus muscle has not been traumatized from previous injury.
■ Standard ABI/TBI exam
■ Evaluate and treat concerns for hardware infection or osteomyelitis.
Positioning
■ Frog leg positioning
Approach
■ Elevate under tourniquet control.
■ Longitudinal skin incision made 2 cm medial to the medial border of the tibia
and parallel to the tibia.
■ Only the muscular portion of the soleus muscle is used as the flap, whereas the

tendon portion of the flap is left intact.
■ To cover a wound at:
■ Middle and distal third of the leg: medial hemisoleus muscle flap is elevated
to the level just below the junction between the proximal and middle third of
the leg for a middle third defect or just above the junction between the middle
and distal thirds of the leg so that an adjacent perforator from the posterior
tibial vessels to the flap can be preserved (FIG 2A).
■ Distal third of the leg: medial hemisoleus muscle flap is elevated only to the
level just below the junction between the middle and distal thirds of the leg,
preserving as many major perforators to the flap as possible, even in the
distal third of the leg while allowing adequate arc of flap rotation (FIG 2B).
FIG 2 • A. Flap dissection and blood supply to the
proximally based medial hemisoleus muscle flap. The
flap receives its blood supply primarily from the
posterior tibial vessels. The flap also receives additional
blood supply from one or two perforators from the
posterior tibial vessels to its distal portion. B. Flap
dissection and blood supply to the distally based medial

hemisoleus muscle flap. The flap receives its blood
supply primarily from the most distal two perforators of
the posterior tibial vessels. The flap also receives
additional blood supply from the proximal source in a
retrograde fashion.
T E C H N I Q U E S
■ Proximally Based Medial Hemisoleus Flap1-3,5,6
■ Identify and dissect free from medial gastrocnemius muscle.
■ Divide distally at the level of the junction between middle and distal thirds
of the leg for covering a middle third defect of the leg or at the level close to
the Achilles tendon if covering the distal third of defect in the leg.
■ Medial half of the muscle is split longitudinally along with a raphe between
the bellies of the soleus muscle.
■ Only one or two distal perforators from the posterior tibial vessels to the
medial hemisoleus muscle are divided so the flap rotation can be facilitated,
but proximal major perforators should be preserved to maximize the blood
supply to the flap (TECH FIG 1A).
■ The spared tendon is approximated to the remaining lateral half of the soleus
muscle with nonabsorbable sutures in a figure of eight fashion to help
minimize the functional loss of the leg after flap harvested (TECH FIG 1B).
■ The elevated hemisoleus muscle flap can be rotated to cover the defect and a
split-thickness skin graft can be placed after flap transfer.

TECH FIG 1 • A. Intraoperative view shows an
adjacent perforator (indicated by forceps) from the
posterior tibial vessels to the medial hemisoleus
muscle flap. Preservation of this perforator can be
critical to ensure an adequate blood supply to the
distal flap. B. The spared conjoined tendon is
approximated to the remaining lateral half of the
soleus muscle with sutures to minimize the functional
loss of the leg after flap elevation.
■ Distally Based Medial Hemisoleus Flap3,4,6
■ Preoperative angiogram can be helpful for determining the presence of major
perforators from posterior tibial vessels to the distal portion of the medial
soleus muscle.
■ Only one or two distal perforators from the posterior tibial vessels to the
medial hemisoleus muscle are divided so the flap turnover can be facilitated;
however, one adjacent proximal perforator should be preserved to maximize
the blood supply to the flap (TECH FIG 2).
■ The medial hemisoleus muscle flap is transposed or turned over into the
defect and inset with absorbable half-buried horizontal mattress sutures.
Scoring the fascia over the medial hemisoleus muscle belly can produce a
few more centimeters of arc of rotation. The muscle flap is covered
immediately with a split-thickness skin graft after flap transfer.

TECH FIG 2 • Intraoperative view shows the first large
perforator (indicated by forceps) from the posterior
tibial vessels to the distally based medial hemisoleus
muscle flap. This perforator serves as a pivot point of
the flap turn over and should be well preserved.
Preservation of this perforator can be critical to ensure
an adequate blood supply to this distally based flap.
PEARLS AND PITFALLS
Muscle damage
■ Before dissecting the medial hemisoleus muscle flap, the
surgeon should make sure that the soleus muscle has not
been traumatized from the previous injury.
Blood supply
■ When performing a proximally based flap, any
perforators from the posterior tibial vessels to the distal
medial half of the soleus muscle just at or above the level

of a tibial wound should be preserved while allowing
adequate arc of flap rotation to cover a wound in the
distal third of the leg.
■ The modifications of surgical techniques emphasize the
preservation of an adequate blood supply to the distal
portion of the medial hemisoleus muscle flap after the
flap is elevated. These techniques would maximize
reliability of the medial hemisoleus muscle flap and
expand its role in reconstruction of a wound in the distal
third of the leg. With the aid of a preoperative angiogram,
major perforators in the lower third of the leg can be
identified when planning a distally based medial
hemisoleus flap.
■ The most proximal perforators from the posterior tibial
vessels to the medial half of the distal soleus muscle
within the upper distal third of the leg should be
preserved while allowing adequate flap turnover to cover
a tibial wound in the distal third of the leg. This
perforator will serve as a pivot point for flap turnover and
the level of the perforator will determine how far this flap
can reach.
■ The modified surgical techniques in flap dissection
emphasize the preservation of an adequate blood supply
to the distal portion of the distally based flap and
maximize reliability of the medial hemisoleus muscle flap
even when it is based distally.
Free tissue transfer8,9
■ Free tissue transfer should still be considered for a larger
soft tissue wound in the middle or distal third of the leg or
for a less extensive wound when either the soleus muscle
or those perforators from the posterior tibial vessels are
traumatized.
POSTOPERATIVE CARE
■ Place patient in knee and ankle immobilizer with minimal pressure on the
transposed flap.
■ Effective leg elevation to reduce edema
■ Placement of a warming unit around leg to maintain a warm temperature
■ Monitoring frequently with clinical assessments
OUTCOMES

■ Based on the author’s experience, the proximally based medial hemisoleus
muscle flap can be used for a relatively proximal tibial wound in the junction
of the middle and distal thirds or in the distal third of the leg.
■ The flap is fairly reliable and can often be done within 2 hours. In addition, the
flap can provide just enough muscle bulk for soft tissue coverage of the tibial
wound, and thus, reconstructive outcomes are usually quite good (FIG 3).
■ The distally based flap can be used for a less extensive distal tibial wound
(often close to the medial malleolus) in the distal third of the leg. The flap can
be reliable in most healthy and compliant patients.
■ The initial venous congestion may also become a problem in certain patients
such as smokers or those with an inability for leg elevation during the
postoperative period.
■ In general, the distal flap necrosis occurs infrequently if the flap is proximally
based but occurs in about 20% of the patients if the flap is distally based (FIG
4).
COMPLICATIONS3,4,6
■ Like any other pedicled flaps, the distal flap necrosis may occur, but total flap
loss should not happen.
■ The distal flap necrosis is usually insignificant and can be managed with
debridement.
■ The flap can then be readvanced adequately to cover the wound, and the final
outcome can still be good.
■ Further advancement of the flap is possible by dividing the most proximal
perforator, which has served as a pivot point since the flap has been “delayed”
after initial flap elevation.

FIG 3 • A. A male patient had a 12 × 6-cm soft tissue
defect in the middle third of the leg with exposed
fracture site. B. A proximally based medial hemisoleus
muscle flap was elevated and rotated to cover the
defect. C. Completion of the muscle flap inset before
placement of skin graft. D. Result at 3.5-month follow-
up.

FIG 4 • A. A female patient had a 6 × 5-cm soft tissue
defect in the distal third of the leg with exposed fracture
site. B. A distally based medial hemisoleus muscle flap
was elevated and turned over to cover the defect. C.
Completion of the muscle flap inset before placement of
skin graft. D. Result at 2-month follow-up before
subsequent bone grafting.
REFERENCES
1. Pu LLQ. Medial hemisoleus muscle flap: a reliable flap for soft tissue
reconstruction of the middle-third tibial wound. Int Surg. 2006;91:194.
2. Pu LLQ. Soft-tissue coverage of an open tibial wound in the junction of the
middle and distal thirds of the leg with the medial hemisoleus muscle flap. Ann
Plast Surg. 2006;56:639.
3. Pu LLQ. Successful soft-tissue coverage of a tibial wound in the distal third of
the leg with a medial hemisoleus flap. Plast Reconstr Surg. 2005;115:245.
4. Pu LLQ. The reversed medial hemisoleus muscle flap and its role in

reconstruction of an open tibial wound in the lower third of the leg. Ann Plast
Surg. 2006;56:59.
5. Pu LLQ. The laterally extended medial hemisoleus flap for reconstruction of a
tibial wound in the distal third of the leg. Eur J Plast Surg. 2007;30:19.
6. Pu LLQ. Further experience with the medial hemisoleus muscle flap for soft-
tissue coverage of a tibial wound in the distal third of the leg. Plast Reconstr
Surg. 2008;121:2024.
7. Tobin GR. Hemisoleus and reversed hemisoleus flaps. Plast Reconstr Surg.
1985;76:87.
8. Pu LLQ. Soft-tissue reconstruction of an open tibial wound in the distal third
of the leg: a new treatment algorithm. Ann Plast Surg. 2007;58:78.
9. Thornton BP, Rosenblum WJ, Pu LLQ. Reconstruction of limited soft-tissue
defect with open tibial fracture in the distal third of the leg. Ann Plast Surg.
2005;54:276.

27
CHAPTER
Section III: Knee
Nerve Repair and
Reconstruction—Tibial
Nerve
Shawn Moshrefi and Catherine Curtin
DEFINITION
■ Tibial nerve injuries can vary in severity, mechanism, and treatment.
■ Nerve injury categories1
■ Neurapraxia: conduction delay with no axonal injury. These injuries will
recover spontaneously without intervention.
■ Axonotmesis: axonal injury resulting in disruption of the axons, but the
supporting nerve scaffolding is intact. In these injuries, distal nerve segment
will undergo Wallerian degeneration and proximal fibers will regenerate.
Spontaneous recovery is possible.
■ Neurotmesis: complete disruption of the nerve. In these injuries, spontaneous
regeneration will not occur.
■ Neuroma in continuity: disruption of the axons though the scaffolding seems
to be intact. However, at the injury site, there is internal fibrosis, which
prevents axons from regenerating. In these injuries, spontaneous regeneration
will not occur.
■ Mixture of injury types: nerve patterns can be complex and one nerve can
have several different types of injury.
ANATOMY (FIG 1)
■ Tibial nerve originates from L4 through S3 nerve roots.
■ The motor branches innervate the posterior calf compartment muscles and the
majority of small muscles in the foot.

■ The sensory branches supply the knee joint, part of the sural nerve
distribution, and the sole of the foot.
■ Tibial nerve branches from the sciatic nerve in the popliteal fossa.
■ The first branch off the tibial nerve is a sensory contribution to the sural nerve.
■ The next branches are the motor nerves to the gastrocnemius muscles.
■ Then, the tibial nerve passes through popliteal fossa under arch of soleus.
(This area is a potential area of tibial nerve entrapment called the soleal sling.)
■ The tibial nerve courses distally adjacent to the tibia on undersurface of soleus
in the leg running with the peroneal artery and vein.
■ At the ankle, tibial nerve is posterior to the medial malleolus adjacent to
posterior tibial artery beneath the flexor retinaculum (This is a potential area of
entrapment known as the tarsal tunnel.) (FIG 2).

FIG 1 • Anatomy of the proximal tibial nerve.
■ At the medial malleolus, the tibial nerve branches into the calcaneal, medial
plantar, and lateral plantar nerves. The anatomy of the branching is highly
variable between patients.2
FIG 2 • Anatomy of the tarsal tunnel.
PATHOGENESIS
■ Tibial nerves can be injured in many ways and in any location along its course.
Listed below are some of the more common causes of tibial nerve injury.
■ Traumatic knee dislocation
■ Direct trauma to the popliteal area, both blunt or sharp
■ Iatrogenic prolonged tourniquet, hardware, or limb lengthening procedures
■ Ankle swelling or compression
■ Cysts or other nerve compressing structures (both in the popliteal fossa as
well as at the medial malleolus)

PATIENT HISTORY AND PHYSICAL FINDINGS
■ A complete and thorough history detailing patient’s history of present illness,
current injuries, history of prior injuries, prior surgeries (including spinal,
buttock, and lower extremity procedures), comorbidities, occupation, and other
case-by-case considerations should be obtained.
■ Inspection
■ Is the calf or foot swollen?
■ Are there vascular changes?
■ Is there atrophy?
■ Vascular exam—palpable pulses distally, temperature, and capillary refill of
the toes and foot.
■ Sensory exam—Ten test: an area of normal or baseline sensation is compared
to an area of concern for sensory loss and the difference is rated from 1 to 10
with 10 being the best score possible.3
■ Motor exam
■ Test the respective muscles that the tibial nerve and its branches supply (tibial
nerve controls plantar flexion and inversion of the foot and ankle).
■ Each individual movement tested should be compared to the contralateral
side. This allows the examiner to identify subtle weakness.
■ Motor examination remember mnemonic TIP = Tibial Inverts and Plantar
flexes.
■ Scratch collapse test.4 This tool originally described for the upper limb is also
useful for assessing nerve entrapment in the lower limb. For this test, the
examiner is testing external rotation of the arm.
■ To do this, the examiner has the patient sitting straight with arms adducted to
their side and elbows bent to 90 degrees. The patient is told to keep the arm in
this position.
■ The examiner then gently scratches the skin directly over the area of
suspected nerve compression (eg, posterior to the medial malleolus for
suspected tarsal tunnel).
■ After scratching the skin, the examiner then directly applies internal rotation
force to the patient’s dorsal forearm while the patient actively attempts to
resist. The test is positive for nerve pathology if the patient is briefly unable
to resist your force of internal rotation.
■ Tinel sign
■ Point tenderness: the tibial nerve can be compressed at the level of the soleal

sling. Patients are often tender to direct pressure over the site (posterior midline
of the calf about 10 cm distal to the posterior knee crease).
IMAGING/STUDIES
■ X-rays are obtained if there is a suspected bony injury.
■ MRI can assess for soft tissue masses such as Baker cysts and also provide
information on the nerve.
■ Enhancement of fascicles on MRI can help identify tibial neuritis (FIG 3).
■ MRI is increasing in resolution and is taking an increasing role in identifying
nerve pathology (FIG 4).
FIG 4 • Comparison of 3T and 7T MRI of tibial nerve.
(Courtesy of Daehyun Yoon, Stanford University.)
FIG 3 • MRI of tibial nerve at soleal sling. Note that the
tibial nerve is bright like the surrounding vessels, and
normal nerve is isointense with the muscle. (Courtesy of
Sandip Biswal, Stanford University.)
■ Nerve conduction studies and electromyelography (NCS/EMG) are a mainstay
in the workup of nerve injury.
■ NCS/EMG useful for closed nerve injury
• Studies are performed at 4 to 6 weeks to achieve a baseline and assess type
and severity of the injury.

• If there is no recovery on physical exam, the nerve studies are repeated at 3
months.
■ If there is evidence of recovery, close follow-up is continued. If no signs of
recovery at three months, operative intervention should be considered. Motor
endplates begin to permanently degenerate at 3 months; thus, if surgery is
required, earlier intervention improves functional outcomes.
DIFFERENTIAL DIAGNOSIS
■ Spinal pathology
■ Sciatic pathology
■ If on physical exam there are deficits in both peroneal nerve and tibial nerve
distributions, then suspect possible sciatic pathology.
■ Neurologic problems
■ Peripheral neuropathy
■ Motor neuron disease
NONOPERATIVE MANAGEMENT
■ For closed nerve injuries, treatment starts with nonoperative management.
■ Therapy
■ Edema prevention with lightly compressive wraps/garments and physical
therapy with massage may be helpful.
■ Range of motion exercises to maintain supple joints and prevent the nerve
from scarring.
■ Desensitization to decrease areas of sensitivity.
■ Orthotics
■ Custom splint that keeps the hindfoot in the neutral position in order to
maintain function and minimize discomfort.
■ Shoe inserts are a first step in people with suspected tarsal tunnel.
SURGICAL MANAGEMENT
■ Surgical treatment is used for open nerve injuries, closed nerve injuries that
are not showing any signs of recovery at 3 months, and nerve compressions
that did not respond to conservative measures.
Preoperative Planning
■ Definitive fracture fixation should be performed prior to nerve repair.
■ Arterial injury should be treated prior to nerve repair.

■ If possible, use of a lower extremity tourniquet is advisable to aid in
visualization of injury.
■ If intraoperative nerve monitoring is planned, inform anesthesia team to not
use paralytics.
Positioning
■ Positioning depends on level of injury (above knee, at level of the knee, or
below knee).
■ Access to popliteal area is easiest with the patient in the prone position.
■ Access to the soleal sling is managed with the patient supine, hip externally
rotated, and knee bent.
■ Access to tarsal tunnel is managed with the patient supine.
Approach
■ For the posterior knee approach, a curved incision rather than a straight
incision across the joint is required to prevent scar contracture that can limit
mobility.
■ For access to the soleal sling, a medial incision on the posterior border of the
tibia starting just distal to the tibial plateau (FIG 5).
■ The tarsal tunnel is accessed posterior to the medial malleolus.
FIG 5 • Incisions for soleal sling and tarsal tunnel
release.
T E C H N I Q U E S

■ Repair of Acute Traumatic Injury to Tibial Nerve
■ Patient positioned supine.
■ Tourniquet placed above the knee.
■ If a wound is present, incorporate wound into exposure.
■ If wound orientation or access is inadequate, then either extend wound
incision to match standard approach or create counter incisions.
■ Resect any damaged or scarred nerve until two healthy nerve ends are
revealed. (The proximal healthy end should have fascicles clearly seen
bulging out the end of the nerve.)
■ Use microsurgical technique to handle the nerve and align the internal
fascicle anatomy.
■ Perform a tensionless repair. (If the 9-0 nylon suture cannot hold the repair,
there is too much tension).
■ If there is a nerve gap, harvest a sural nerve graft.
■ Cable the graft and suture in place with a few 9-0 nylon sutures using
microscopic technique.
■ Augment repair by sealing coaptation site with fibrin glue.
■ Closure of wound.
■ Place in a leg splint or knee immobilizer to protect repair.
■ Release of Soleal Sling5
■ Anesthesia options: regional anesthetic (popliteal/distal sciatic block and
saphenous block) or general anesthesia
■ Patient is supine and the hip is externally rotated, exposing the medial side
of the leg.
■ A thigh tourniquet is placed.
■ The incision is placed at the medial tibial plateau and runs distally for about
10 cm and is placed about 1 cm posterior to the medial edge of the tibia
(TECH FIG 1A).
■ The subcutaneous tissue is carefully dissected, preserving the saphenous
nerve and vein.
■ The fascia over the gastrocnemius is opened and the plane between the
soleus is identified.

■ The gastrocnemius is retracted out of the way.
■ The soleal sling can be palpated with a finger as a fascial notch in the
proximal border of the muscle.
■ The medial soleal muscle is reflected and perforating vessels are clipped.
■ The tibial nerve is identified and a vessel loop is placed.
■ Constricting fascial bands are released over about a 5 cm length.
■ Skin is closed and a bulky dressing placed.
■ Early ambulation is encouraged.
■ Release of Tarsal Tunnel
■ Patient is placed supine.
■ Regional block of the popliteal and saphenous nerve is performed.
■ Tourniquet is placed on the calf.
■ A bent incision is placed posterior to medial malleolus.
■ Skin and subcutaneous tissue are divided.
■ Care is taken to preserve the overlying sensory nerves.
■ The flexor retinaculum is incised proximally and the posterior tibial vessels
are visualized below. Small crossing vessels are clipped.
■ The nerve is identified deep to the vessels and a loop is placed around the
nerve.
■ The dissection is taken distally and the branches are identified. (Note the
calcaneal branches have variable anatomy and number) (TECH FIG 1B).
■ The medial and lateral plantar nerves are identified and loops placed.
■ The fascia overlying the medial and lateral plantar nerves is divided
including the fascia overlying the abductor hallucis.
■ All fascia must be released distally and the dissecting scissors can easily fit
in the tunnels over the medial and lateral plantar nerves.
■ Meticulous hemostasis is required.
■ Closure and placement of a bulky dressing
■ Early ambulation is encouraged.

TECH FIG 1 • A. Tibial nerve exposed through soleal
sling. Note the deep exposure required. The tibial
nerve is at the base of the wound identified by the
forceps. B. Tibial nerve exposed in a tarsal tunnel
release. Note the multiple calcaneal branches going
posteriorly.
■ Tibial Nerve Traction Injury
■ General anesthesia
■ Thigh tourniquet (to obtain optimal nerve monitoring results the tourniquet
needs to be released for 20 minutes). If tourniquet is not used, preinject with
bupivacaine with epinephrine prior to prepping the patient.
■ Prone positioning
■ Intraoperative nerve monitoring should be available.
■ Incision is angled from the center of popliteal fossa.
■ The dissection is taken down to the level of the muscle fascia.
■ The tibial nerve is identified as it branches off the sciatic nerve.
■ A vessel loop is placed on the nerve and the dissection is taken distally.
■ The nerve is released from the overlying scar (often a very challenging
dissection). The dissection is taken posterior to the gastrocnemius muscles to
release the soleal sling.
■ Intraoperative nerve monitoring is performed. Starting with somatosensory
evoked potentials can help establish the proximal level of intact nerve. Nerve
to nerve monitoring can identify neuroma in continuity.
■ If the nerve is ruptured or neuroma in continuity is identified, resect
damaged or scarred nerve until two healthy nerve ends are revealed.

■ Ensure that the proximal nerve is healthy by using the assistance of your
neurologist performing the intraoperative nerve monitoring.
■ If there is a nerve gap, harvest a sural nerve graft.
■ Cable the graft and suture in place with 9-0 nylon sutures using microscopic
technique.
■ Augment repair by sealing coaptation site with fibrin glue.
■ Closure of wound
■ Place in a leg splint or knee immobilizer to protect repair.
PEARLS AND PITFALLS
Hemostasis
(if no
tourniquet)
■ Preinject incision with bupivacaine with epinephrine.
■ A solution of 1 amp of epinephrine diluted in 100 cc of saline can
be used to moisten a gauze that is then dabbed in the wound to
help with visualization.
Technique
■ To ensure complete release of the tarsal tunnel, the distal
compression of the medial and lateral plantar nerves must be
released. The distal dissection is challenging due to the overlying
vessels. Clip crossing vessels as needed to adequately expose the
nerves.
Intraoperative
monitoring
■ Communication between neurology and anesthesia team is critical
to ensure that patient does not receive medications that will hinder
intraoperative monitoring.
■ Sequential compression device machine and warming machines
can cause background that interferes with intraoperative
monitoring.
■ Do not use tourniquet if planning intraoperative monitoring. The
nerve can suffer neuropraxia after 30 minutes of ischemia.
Diagnosis
■ MRI imaging can help if proximal nerve entrapment suspected.
POSTOPERATIVE CARE
■ Postoperative splint utilized for 3 weeks if there is a nerve repair to protect
■ Early mobilization for neurolysis patients
■ Affected lower extremity should be elevated at all times initially to aid in

reduction of swelling.
■ Multimodal pain management for postoperative pain
■ Early therapy for desensitization, scar management, and nerve gliding
OUTCOMES
■ The literature on results from tibial nerve surgery is sparse.
■ Tarsal tunnel release is an effective procedure when performed properly. A
case series found that patients improved their Maryland Foot Score from 61 to
80, 3 months after tarsal tunnel release.6
■ Tarsal tunnel release can fail for several reasons including incorrect diagnosis,
proximal compression, and intrinsic nerve damage.7
COMPLICATIONS
■ Neuropathic pain
■ Inadequate release
■ Bleeding/hematoma
REFERENCES
1. Seddon HJ. A classification of nerve injuries. Br Med J. 1942;2:237-239.
2. Havel PE, Ebraheim NA, Clark SE, et al. Tibial nerve branching in the tarsal
tunnel. Foot Ankle. 1988;9(3):117-119.
3. Strauch B, Lang A, Ferder M, et al. The ten test. Plast Reconstr Surg.
1997;99:1074-1078.
4. Cheng CJ, Mackinnon-Patterson B, Beck JL, Mackinnon SE. Scratch collapse
test for evaluation of carpal and cubital tunnel syndrome. J Hand Surg [Am].
2008;33(9):1518-1524.
5. Williams EH, Rosson GD, Hagan RR, et al. Soleal sling syndrome (proximal
tibial nerve compression): results of surgical decompression. Plast Reconstr
Surg. 2012;129(2):454-462.
6. Sammarco GJ, Chang L. Outcome of surgical treatment of tarsal tunnel
syndrome. Foot Ankle Int. 2003;24(2):125-131.
7. Gould JS. Recurrent tarsal tunnel syndrome. Foot Ankle Clin. 2014;19(3):451-
467.

28
CHAPTER
Excision of Soft Tissue
Tumors of the Knee
Raffi S. Avedian
DEFINITION
■ Soft tissue sarcomas are malignant tumors that arise from mesenchymal cells
and are classified according to their cell of origin such as muscle, tendon, or
fat.
■ Peripheral nerve sheath tumors arise from neural crest cells but are typically
grouped with sarcomas because of similarities in location, natural history, and
treatment.
■ The World Health Organization groups soft tissue sarcomas into 10
categories based on the tissue of origin.
■ Most sarcomas occur in a deep location, meaning below the muscle and fascia,
whereas one-third of sarcomas occur in a subcutaneous location.
■ Patients with soft tissue sarcomas and patients with benign tumors often
present with the same chief complaint of having a soft tissue mass.
■ Rendering an accurate diagnosis prior to surgery is important because the
treatment plan may vary based on the nature of the diagnosis. For example, a
benign tumor may be monitored or removed with a simple excision, whereas
in the case of a sarcoma, the goal of surgery is to remove the tumor with a
wide margin. With appropriate planning, radiotherapy and/or chemotherapy is
often incorporated into the treatment plan either before or after definitive
surgery.
ANATOMY
■ The knee is the largest joint in the body. It is made up of the patellofemoral,
lateral, and medial compartments.
■ Knee motion is primarily flexion and extension; however, bending and rotation

are important components of knee kinematics.
■ The primary stabilizers of the knee are the extra-articular medial and lateral
cruciate ligaments and intra-articular anterior and posterior cruciate ligaments.
■ The knee has several layers of covering including the capsule and retinacular
tissues. During tumor resection, superficial layers may be used as the deep
margin for the tumor, whereas the deeper capsule may be preserved to keep the
joint closed.1
■ The popliteal artery travels along the back of the knee and along with the tibial
nerve travels between the lateral and medial head of the gastrocnemius. It
branches into the posterior tibial artery, which travels deep to the soleus
muscles; the anterior tibial artery, which passes from posterior to the anterior
compartment distal to the tibia-fibula joint; and the peroneal artery, which
branches off the tibiofibular trunk and is located medial to the fibula next to the
flexor hallucis longus.
■ The geniculate vessels branch off from the popliteal vessels and are often all
ligated during tumor resection of the distal femur.
■ The tibial nerve is located next to the popliteal vessels. The common peroneal
nerve travels medial and deep to the biceps femoris muscle, a constant
relationship that facilitates finding and protecting the nerve during tumor
dissection.
■ The common peroneal nerve wraps around the neck of the fibula and divides
into the deep branch that innervates the anterior muscle compartment and the
superficial branch that innervates the lateral compartment.
■ The lateral sural cutaneous nerve, which branches off the common peroneal
nerve, may be large in some patients and be confused with the common
peroneal nerve.
PATHOGENESIS
■ The mechanism for sarcoma formation is not known.
■ Risk factors for sarcoma development include radiation exposure such as
medical radiotherapy, pesticide exposure, and hereditary conditions including
Li-Fraumeni syndrome and neurofibromatosis.
NATURAL HISTORY
■ All sarcomas have the potential for local recurrence and metastasis.
■ Tumor variables that are associated with increased risk of metastasis include
high grade and large size (greater than 5 cm).

■ Lungs are the most common location of metastasis.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Determining when the mass was first noticed and how rapidly it is growing
can help the clinician differentiate between benign and malignant tumors.
■ The presence of pain is often associated with a benign tumor, such as a
schwannoma or vascular malformation, and may not be present with sarcomas
until late in the disease course.2
■ Determining the size of the tumor, manual muscle strength testing, and sensory
examination are useful to determine if there is a neurological compromise.
Limb edema assessment and pulse examination can help determine if the tumor
is causing vascular or lymphatic compromise.
■ Range of motion testing and gait assessment are helpful in assessing a
patient’s mobility and functional status to guide perioperative and
postoperative counseling.
IMAGING
■ Plain radiographs can help diagnose joint degeneration or joint-based lesions
such as gout and synovial osteochondromatosis.
■ Magnetic resonance imaging is the modality of choice for soft tissue tumor
evaluation (FIG 1A,B).
■ Fat-sensitive images such as T1-weighted sequences are best for identifying
critical anatomic structures such as nerves and vessels.
■ Fluid-sensitive images including T2-weighted and STIR sequences highlight
pathology very well.
■ Contrast-enhanced sequences are used to differentiated cystic from solid areas
in tumors and identify reactive peritumoral edema, which will be high signal
on fluid sequences but not enhance with contrast.
■ Some benign tumors such as lipoma, lipoma arborescens, and schwannoma
may be diagnosed on MRI; however, most soft tissue tumors require a biopsy
for diagnosis.3

FIG 1 • A. Coronal and axial (B) MRIs demonstrating a
high-grade soft tissue sarcoma abutting the proximal
tibia and knee joint.
DIFFERENTIAL DIAGNOSIS
■ Giant cell tumor of tendon sheath
■ Synovial chondromatosis
■ Lipoma arborescens
■ Other benign tumors
■ Sarcoma
■ Reactive and inflammatory lesions such as gout or infection
SURGICAL MANAGEMENT
■ The appropriate treatment for any musculoskeletal tumor is based on its
diagnosis and natural history.
■ Performing a surgery without consideration of the diagnosis and the
appropriate margin may cause harm to patients.4
■ In cases where MR imaging is not diagnostic, a biopsy should be performed.
■ Treatment strategy including the use of preoperative radiation and specific
surgical plan should be formulated by a multidisciplinary team specializing in
sarcoma care.5
■ Treatment of knee tumors may require resection of the joint capsule, extensor
mechanism, and/or stabilizing structures such as the collateral ligaments.
Reconstruction of these structures should be accounted in the operative plan.
Preoperative Planning

■ A patient is considered ready for surgery after completion of staging and
multidisciplinary review of pertinent imaging, pathology, and treatment
strategy.
■ The surgical plan is created by thorough study of the preoperative MR scan. A
plane of surgical dissection is planned to remove the tumor in its entirety while
maintain a clean margin around it.
■ If the tumor encases important vascular structures, a plan for vascular
reconstruction is made with a vascular surgeon.
■ Anticipated soft tissue coverage needs are assessed such as skin graft, local
rotation flap, or free tissue transfer.
Positioning
■ The patient is placed in the supine position unless the tumor is in the posterior
compartment in which case the patient is placed in the prone position.
■ The site of a flap harvest must be completely isolated from the tumor site to
avoid contamination and tumor spread. A separate back table and clean
instruments should be used.
Approach
■ The surgical approach varies based on location of the tumor.
■ Previous biopsy and surgical scars are considered contaminated and must be
excised en bloc with the tumor.
T E C H N I Q U E S
■ Wide Resection of a Knee Sarcoma
■ Most knee tumors are subcutaneous and require a paddle of skin to be
removed as the superficial margin.
■ An incision is made 2 to 3 cm peripheral to the edge of the tumor as
determined by palpation and preoperative MRI (TECH FIG 1A).
■ The dissection is carried through the subcutaneous fat angling away from the
tumor (TECH FIG 1B).
■ The deep fascia is identified and cut circumferentially around the tumor
(TECH FIG 1C).

■ For tumors abutting the joint capsule, the surgeon must assess if the tumor is
adherent to the capsule, in which case the entire capsule must be removed, or
if the tumor only abuts the capsule in which case only the retinaculum needs
to be removed.
■ Sutures may be used to secure the deep layer to the skin to prevent the tumor
from “leaking out” of the superficial layer.
■ Take care not to shear off the fat from the fascia during dissection.
■ Avoid retractors on the tumor side of the dissection.
■ Do not sacrifice margin in order to save tissue for a primary closure (TECH
FIG 1D).
■ Most surgeries require a skin graft or muscle flap for closure (TECH FIG
1E,F).
TECH FIG 1 • A. Planned skin incision. Notice the
margin of skin around the palpable tumor. B.
Superficial dissection of skin and subcutaneous tissue
and identification of the common peroneal and lateral
sural cutaneous nerves. C. The deep fascia is cut
peripherally and a small cuff of muscle and retinacular
tissue is removed as the deep margin. The muscular
branches of the peroneal nerve are preserved. D.
Defect after tumor removal. E,F. Lateral
gastrocnemius muscle flap is rotated to cover the

defect and split-thickness skin graft applied.
PEARLS AND PITFALLS
Hematoma
■ Dead space after tumor removal should be managed with drains,
muscle flap, free tissue transfer, or a combination of these techniques.
■ Seroma drainage in the clinic may be necessary.
Wound
breakdown
■ Negative pressure dressings, aggressive dead space management, and
maximizing patients’ nutrition may reduce wound problems.
■ Patients should be counseled about potential need for reoperation for
wound management.
Positive
margins
■ Appropriate preoperative planning is important to minimize risk of
unplanned positive margins.
■ Planned positive margins around critical structures such as nerves and
vessels may be appropriate in certain settings.
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 after wound healing is sufficient.
■ Postoperative radiotherapy, if needed, may be take place 4 to 6 weeks after
surgery.
OUTCOMES
■ Oncological outcomes include local recurrence and metastasis. Surveillance
for recurrence should be managed by a multidisciplinary sarcoma team.
■ Functional outcomes depend on the extent of tissue resection, patient overall
health status, and late effects of radiation. Aggressive wound care and physical
therapy may help maximize patient function.
COMPLICATIONS
■ Wound healing problems that require operative intervention can occur in up to
33% of patients who undergo preoperative radiotherapy and 17% of patients
who undergo postoperative radiotherapy.6
■ Local recurrence occurs in a minority of patients and is more common in

patients with positive margins. Radiotherapy decreases the risk of local
recurrence.
REFERENCES
1. Dye SF, Campagna-Pinto D, Dye CC, et al. Soft-tissue anatomy anterior to the
human patella. J Bone Joint Surg Am. 2003;85-A(6):1012-1017.
2. George A, Grimer R. Early symptoms of bone and soft tissue sarcomas: could
they be diagnosed earlier? Ann R Coll Surg Engl. 2012;94(4):261-266.
3. Jim S, Wu MD, Mary G, Hochman MD. Soft-tissue tumors and tumorlike
lesions: a systematic imaging approach. Radiology. 2009;253(2):297-316.
4. Jones DA, Shideman C, Yuan J, et al. Management of unplanned excision for
soft-tissue sarcoma with preoperative radiotherapy followed by definitive
resection. Am J Clin Oncol. 2016;39(6):586-592.
5. Siegel GW, Biermann JS, Chugh R, et al. The multidisciplinary management
of bone and soft tissue sarcoma: an essential organizational framework. J
Multidiscip Healthc. 2015;8:109-115.
6. O’Sullivan B, Davis AM, Turcotte R, et al. Preoperative versus postoperative
radiotherapy in soft-tissue sarcoma of the limbs: a randomised trial. Lancet.
2002;359(9325):2235-2241.

29
CHAPTER
Excision of Bone Tumors of
the Knee
Raffi S. Avedian
DEFINITION
■ Bone tumors of the knee may be benign or malignant (bone sarcoma) and
exhibit a variable natural history ranging from latent to rapid growth.
■ A bone tumor located in the distal femur or proximal tibia such that definitive
treatment requires excision of part or all of the knee is discussed in this chapter.
■ Treatment for a bone tumor of the knee requires reconstruction of the knee
articulation.
ANATOMY
■ The knee is the largest joint in the body. It is made up of the patellofemoral,
lateral, and medial compartments.
■ Knee motion is primarily flexion and extension; however, bending and rotation
are important components of knee kinematics.
■ The primary stabilizers of the knee are the extra-articular medial and lateral
cruciate ligaments and intra-articular anterior and posterior cruciate ligaments.
■ The popliteal artery travels along the back of the knee and along with the tibial
nerve travels between the lateral and medial head of the gastrocnemius. It
branches into the posterior tibial artery, which travels deep to the soleus
muscles; the anterior tibial artery, which passes from posterior to the anterior
compartment distal to the tibia-fibula joint; and the peroneal artery, which
branches off the tibiofibular trunk and is located medial to the fibula next to the
flexor hallucis longus.
■ The geniculate vessels branch off from the popliteal vessels and are often all
ligated during tumor resection of the distal femur.
■ The tibial nerve is located next to the popliteal vessels. The common peroneal

nerve travels medial and deep to the biceps femoris muscle; a constant
relationship that facilitates finding and protecting the nerve during tumor
dissection.
PATHOGENESIS
■ The mechanism for bone tumor formation is not known.
■ Risk factors for sarcoma development include radiation exposure,
radiotherapy, pesticide exposure, and hereditary conditions including Li-
Fraumeni syndrome and retinoblastoma gene mutation.1
NATURAL HISTORY
■ Active benign tumors, such as giant cell tumor of bone, chondroblastoma, and
aneurysmal bone cyst, will progress over time, may recur after excision, but are
not lethal.
■ All bone sarcomas have the potential for local recurrence and metastasis.
■ Bones sarcomas have an estimated incidence of 3260 in the United States.
■ Lungs and other osseous sites are the most and second most common location
of metastasis, respectively.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Pain is a common presenting symptom for aggressive bone tumors.
■ A thorough history and examination are important to assess duration of
symptoms, comorbidities, physical dysfunction, organ involvement, overall
health, and patient expectations in order to best tailor treatment strategy for the
individual patient.
■ Neurovascular examination is mandatory for any extremity tumor.
IMAGING
■ Plain radiographs are used to formulate a differential diagnosis and a
preoperative plan.
■ Magnetic resonance imaging is routinely used to determine extent of
intramedullary tumor involvement, presence of soft tissue extension, status of
the neurovascular structures, and presence of tumor within the joint space.
DIFFERENTIAL DIAGNOSIS
■ The differential diagnosis for a bone tumor includes benign tumors, sarcomas,
lymphoma of bone, infection, and metabolic lesions (eg, hyperparathyroidism).
■ The most common bone sarcomas are osteosarcoma, chondrosarcoma, and

Ewing sarcoma.
SURGICAL MANAGEMENT
■ The appropriate treatment for any musculoskeletal tumor is based on its
diagnosis and natural history.
■ Biopsy incisions are considered contaminated and must be resected at the time
of definitive surgery. Care should be taken to place the biopsy in a location that
does not interfere with the final surgical plan.2
■ If a bone sarcoma extends into the knee joint space by direct growth,
pathological fracture, or iatrogenic contamination, an extra-articular resection
(keeping the knee joint closed) should be performed.
■ Reconstruction depends on the extent of bone excision and may include simple
bone grafting, endoprosthetic implants, bulk allografts, osteoarticular implants,
or vascularized fibula.
■ The goal of surgery is to remove the tumor adequately to minimize recurrence
and restore the mechanical integrity of the bone and joints so that the patient
may have sufficient function to perform activities of daily living with minimal
pain.
Preoperative Planning
■ A patient is considered ready for surgery after completion of staging and
multidisciplinary review of pertinent imaging, pathology, and treatment
strategy.
■ The surgical plan is created by thorough study of the preoperative radiographs
and MR scan.
■ Bone cuts are planned by measuring on preoperative imaging the distance
from an intraoperatively identifiable landmark (eg, femoral condyle,
epicondyle) to the desired osteotomy site.
■ The soft tissue margin depends on the size and location of a soft tissue
component to the tumor. For example, an anterior soft tissue mass long the
distal femur can be safely resected by incorporating a portion of the vastus
intermedius as the margin.
■ When tumor abuts but does not encase blood vessels or nerves, they can be
dissected free by leaving adventitia and epineurium on the tumor as the margin.
Positioning
■ The patient is placed in the supine position; a hip bump may be placed if more

lateral exposure is desired.
■ A sterile or nonsterile tourniquet may be used.
■ A leg holder may be used in cases where an endoprosthetic knee replacement
is being performed.
Approach
■ The surgical approach varies based on location of the tumor.
■ The guiding principles for the approach to the knee in the setting of a bone
sarcoma are to maintain a sufficient margin around the tumor and preserve as
much normal tissue as possible without sacrificing cancer treatment.
■ Previous biopsy and surgical scars are considered contaminated and must be
excised en bloc with the tumor.
T E C H N I Q U E S
■ Distal Femur Resection and Endoprosthetic
Reconstruction
■ Tourniquet is used at the discretion of the surgeon by using gravity
exsanguination rather than Esmarch to avoid tumor compression
■ A longitudinal incision is made that includes a fusiform skin excision of the
biopsy site. Skin flaps are created as needed to ensure adequate visualization
of the tumor and critical anatomy.
■ Soft tissue dissection around the tumor is performed with the following
principles:
■ Adequate visualization must be achieved.
■ Margin of healthy tissue is kept on the tumor.
■ Nerves are dissected free; epineurium may be used as margin if tumor
abuts the nerve. Sciatic nerve branches to hamstring muscles may be cut as
needed to adequately mobilize the nerve away from the tumor.
■ Vessels are mobilized; adventitia may be used as margin if tumor abuts the
vessels.
■ Tumor removal may be broken down into four steps:
■ Knee disarticulation: perform an arthrotomy and cut collateral and cruciate
ligaments, joint capsule, gastrocnemius origins, and popliteus tendon.

■ Neurovascular mobilization: the popliteal vessels must be mobilized by
dividing the geniculate branches and dissecting the vessels free from the
adductor canal. The tibial nerve is located next to the vessels and the
common peroneal nerve is located medial to the biceps femoris. They
should be identified and mobilized away from the tumor as needed.
■ Muscle dissection: often bone sarcomas of the distal femur or proximal
tibia will have a soft tissue component. The muscle layer immediately
covering the tumor is removed as the margin. For example, the vastus
intermedius serves as good margin for anterior soft tissue masses. The
lateral and medial intermuscular septa must be divided as close to the bone
as tumor margin permits.
■ Osteotomy: Measure the length of bone to be resected on preoperative MRI
and translate that to intraoperative landmarks such as a measurement from
the femoral condyle to the femoral diaphysis above the tumor. Bennett or
Hohmann retractors are placed around the bone to prevent iatrogenic
neurovascular injury and an oscillating saw is used to complete the
osteotomy.
■ The remaining posterior soft tissue attachments are cut, and the specimen is
removed.
■ Leg length can be restored by measuring the contralateral leg from the
anterior superior iliac spine to the medial malleolus and recreating this on the
operative side or measuring and recreating the length of bone removed from
the affected side (TECH FIG 1).
TECH FIG 1 • Intraoperative photograph
demonstrating technique for leg length recreation.

Trial implants are measured side by side with femur
and tibial plateau to ensure what goes into patient
matches exactly what was taken out.
■ Reconstruction
■ The femur is prepared for endoprosthetic reconstruction using one of the
currently available fixation techniques: a cemented stem, uncemented stem,
or compress compliant prestress device (TECH FIG 2).
■ Rotational alignment can be achieved by using the linea aspera as a posterior
landmark. Also, trial implants may be placed and the knee taken through a
range of motion check to ensure proper rotation of implants and patellar
tracking. Once the surgeon is satisfied with the rotation, a mark is placed on
the bone denoting anterior. This mark is used as a guide for correct insertion
of the final implant.
■ Deep drains are placed, and the deep fascia is closed over drains, followed
by a subcutaneous fascia and dermal layer.

TECH FIG 2 • A. Anteroposterior radiograph of a 14-
year-old boy with a distal femur osteosarcoma. B.
Coronal MRI demonstrating large intramedullary
extension and soft tissue mass. C. Sagittal MRI after
induction chemotherapy demonstrating tumor extent
and measurement for planned osteotomy. D. Axial
MRI demonstrating soft tissue mass in vastus lateralis

and popliteal fossa abutting sciatic nerve and vessels.
E. Intraoperative photograph after initial dissection
around tumor, note a portion of the vastus lateralis is
left on the tumor as a margin and the femur is
exposed proximal to the tumor in anticipation of
osteotomy. F. After osteotomy, the femur is lifted out of
the wound to facilitated dissection of the posterior
anatomy including the sciatic nerve and femoral
vessels as they pass through the adductor canal. G.
Photograph showing that the ligamentous structures
of the knee including the capsule are identified and
cut. H. Photograph of defect after tumor removal. I.
Endoprosthetic reconstruction is performed including
large metal segment to replace bone and a hinged
total knee arthroplasty. J. Lateral radiograph 4 months
after surgery.
■ Endoprosthetic Reconstruction of the Proximal
Tibia
■ The principles of distal femur tumor resection outlined in the previous
section apply to resection of tumors of the proximal tibia.
■ Unique aspects of proximal tibia resection include the following (TECH
FIG 3):
■ Large skin flaps must be raised to visualize critical anatomy.
■ Patellar tendon must be detached from the tibial tubercle and subsequently
reconstructed.
■ The popliteus muscle can be used as the margin covering posterior soft
tissue masses.
■ The anterior tibial artery often must be ligated and divided as it branches
from the popliteal artery at the lower order of the popliteus muscle.
■ The proximal fibula may be excised along with the tibia depending on the
lateral extent of the tumor.
■ The patellar tendon may be repaired using 5-mm Mersilene tape sewed into

the tendon using Krackow stitches, the ends of which are then tied into the
endoprosthesis.
■ The repair may be reinforced using no. 5 nonabsorbable to sew the tendon
down into additional holes in the endoprosthesis either directly or after
cerclage around the patella.
■ A gastrocnemius flap is elevated and rotated to cover the prosthesis and
provide biological augmentation to the patellar tendon repair.
■ A deep drain is placed, and the wound is closed in layers. A split-thickness
skin graft is often needed to cover a portion of the gastrocnemius flap.
TECH FIG 3 • A. Anteroposterior radiograph of a 61-
year-old man with a proximal tibia chondrosarcoma.
B. MRI demonstrating tumor extent. C. Intraoperative
photograph showing initial dissection including large
skin flaps to enable adequate visualization. D. Deep
dissection is performed by identifying the popliteal
vessels and tibial nerve and mobilizing healthy muscle