Operative Technique in Plastic Surgery – Kevin C.Chung

■ Midcarpal examination can be performed from either the radial or ulnar
midcarpal port or occasionally the scaphotrapeziotrapezoid joint (STT) port.
■ When using the radial midcarpal portal, orientation can be quickly
established by recognizing the concave surfaces of the proximal row articular
surfaces and the dramatically convex articular surface of the head of the
capitate and pole of the hamate (TECH FIG 6).
■ Identify the cleft at the proximal extent of the capitohamate joint.
■ Reorient the scope to direct it distally into the dorsal aspect of the midcarpal
joint over the STT joint. This is accomplished by dropping the scope into a
line tangential to the plane of the forearm.
■ Rotation of the arthroscope in this region will visualize the STT joint and the
curvature of the distal articular surface of the scaphoid. A cleft can be
visualized between the trapezium and trapezoid and the radial aspect of the
STT ligament along the lateral aspect of the STT joint.
■ Moving the arthroscope proximally from the STT joint, the scaphocapitate
(SC) articulation comes into view. The SC joint is a “tight” joint, and
transverse fibers of the SC ligament are sometimes seen but not always due
to difficulty positioning the arthroscope.
SL Joint
■ As the arthroscope is continually drawn more proximally, the distal cleft of
the SL joint is visualized. The SL joint should be visualized from at least two
portals to change the orientation of view and prevent a false sense of a step-
off.
■ When visualizing the SL joint, take care to ensure that the arthroscope is not
exerting pressure on either the scaphoid or lunate, forcing them out of
alignment.
■ The SL joint should be evaluated visually and by using a 3-mm probe
according to the Geissler grading scale (TECH FIG 7).5
■ Under normal conditions, it is difficult to pass an arthroscopic probe into the
SL or LT joint and rotate it. When there is a SL ligament disruption, the scope
can enter into the joint space; this is referred to as the “drive-through sign”
(TECH FIG 8).
■ From the midcarpal portals, the volar midcarpal joint capsule, with its
generous synovial stratum, can be assessed, as well as the “space of Poirier”
by palpating the volar capsule with the probe to detect a groove between the

arcuate ligament (RSC and UC) and the lunate.
Ulnar Structures
■ A complete assessment of the midcarpal joint includes the ulnar structures.
Moving the scope ulnarly, the distal articular surface of the lunate can be
inspected as well as the LT joint cleft (TECH FIG 9).
TECH FIG 6 • A. Diagram of the right wrist, dorsal
arthroscopy of the midcarpal joint from the radial
midcarpal portal. B. Visualization of the capitohamate
joint allows for orientation in the midcarpal joint.

TECH FIG 7 • A. Diagram of right wrist, dorsal
arthroscopy of the midcarpal joint, indicating
arthroscopic field of view of the SL joint from the radial
midcarpal portal. B. Hemorrhagic synovitis at the
scaphocapitate joint.
TECH FIG 8 • A. Diagram of the right wrist. B. “Drive-
through sign” of the SL interval indicating a Geisler-

type IV injury.
TECH FIG 9 • A. Diagram of right wrist, dorsal
arthroscopy of the midcarpal joint, indicating
arthroscopic field of view of the LT joint from the radial
midcarpal portal. B. Intraoperative arthroscopic view
of the capitate and hamate above, and (C) a 3-mm
probe inserted through the ulnar midcarpal portal
testing an intact LT joint.
Table 6 Radial Midcarpal Portal Field of View
Surface Anatomic Landmark: Radial Side of the Third Metacarpal Axis
Proximal to the Capitate in a Soft Depression Between the Capitate and
Scaphoid
Portal Field of View
Portal
Name
Radial
Central
Volar
Dorsal/Distal Ulnar
Midcarpal
radial
portal
STT joint,
distal
scaphoid
pole
SLIL joint,
distal
scaphoid,
distal
lunate
Radial limb
of arcuate
ligament, ie,
continuation
of RSC
ligament
Proximal
capitate,
CHIL,
oblique
views of
proximal
hamate
LTIL joint,
partial
triquetrum
■ The LT can be palpated with a 3-mm probe and can also be graded using the
Geissler grading scale.5

■ Further ulnar movement can assess the palmar ligaments (ulnocapitate,
triquetrocapitate, and triquetrohamate) after gently scraping the volar capsule
synovial stratum.
■ By dorsally rotating the scope at this position, the articular surfaces of the
distal triquetrum (spiral shaped) and the proximal hamate (elliptical shape)
can be inspected.
■ Further ulnar movement of the scope will visualize a large joint recess and
the “bare area” on the capitate neck and head and the pole of the hamate;
however, due to excess synovial tissue, this view is often obscured.
■ Tables 6 and 7 cover the radial and ulnar midcarpal portal fields of view,
respectively.
Table 7 Ulnar Midcarpal Portal Field of View
Surface Anatomic Landmark: 1 cm Distal to the 4-5 Portal, Aligned with the
Fourth Metacarpal, at the Lunotriquetral-Capitate-Hamate Joint
Portal Field of View
Portal
Name
Radial
Central Volar
Dorsal/Distal Ulnar
Midcarpal
ulnar
portal
Distal
articular
surface
of
scaphoid
Distal
lunate
Volar limb of
arcuate ligament, ie,
continuation of
triquetrocapitolunate
Oblique
views of
proximal
capitate,
CHIL,
proximal
hamate
LTIL joint,
triquetrum
PEARLS AND PITFALLS
Incisions
■ Superficial longitudinal (or transverse) dermal incision followed
by blunt dissection with a mosquito (or tenotomy dissection) to
protect the extensor tendons and dorsal sensory nerve branches

Portal
placement
■ Reposition the trocar if not inserting easily, to avoid chondral
injury. Always use the blunt trocar to enter into the joint.
Arthroscopy
fluid
■ Normal saline is injected to confirm placement of portals in the
wrist, and arthroscopic examination can be performed either
with or without fluid. However, use of heat-producing
equipment should only be performed with arthroscopic fluid to
avoid thermal injuries. We recommend the wet technique.
Inadequate
views
■ Synovitis, fractures, ligament tears, and tight wrist capsule may
limit the field of view during wrist arthroscopy requiring use of
more portals to adequately assess the wrist.
Traction
■ Wrist traction often diminishes throughout the examination and
should be readjusted to avoid inadvertent chondral injury from
instruments.
Standardization
■ A standard approach to wrist arthroscopy optimizes efficiency
and ensures a thorough and complete examination of the wrist.
DRY ARTHROSCOPY
Preventing
capsule
collapse
■ The valve of the sheath of the scope should be open at all times
for air to circulate within the joint; otherwise, the capsule will
collapse inward when using suction, obstructing the view.
Limited use of
suction
■ Open the suction only when needing to aspirate something, or
debris may be stirred up that may stick to the tip of the scope.
Avoiding
splashes
■ Avoid using the burs or osteotomes too close to the tip of the
scope as minor splashes may block your vision. Minor splashes
can be removed by gently rubbing the tip of the scope on the
local soft tissue.
Clearing field
with saline
■ When a clear field is needed, a syringe with 5–10 mL of saline
may be connected to the side valve of the scope and then
aspirated with an arthroscopic shaver to get rid of blood and
debris. The negative pressure exerted by the shaver will suck the
saline into the joint without any pressure on the plunger and
prevent extravasation.
Preventing
suction clog
■ Periodic saline aspiration from an external basin or by joint
irrigation, and systematic joint flushing in some procedures
(intercarpal arthrodesis, arthroscopic proximal carpectomy)
during prolonged use of burs, which may cause heating of
instrument and local burns

POSTOPERATIVE CARE
■ Splinting:
■ Diagnostic: 4 to 7 days for comfort.
■ Arthroscopic reduction and scapholunate pinning: sugar-tong splint for 2
weeks, followed by short-arm cast for 8 weeks. Pins are removed at 10 weeks.
Removable splint for 2 to 4 more weeks.
■ Open ligament repair with scapholunate pinning: sugar-tong splint for 2
weeks, followed by short-arm cast for 10 weeks. Pins are removed at 10
weeks. Removable splint for 2 to 4 more weeks.
■ TFCC debridement: volar resting splint for 2 weeks, and then begin range of
motion exercises.
■ TFCC arthroscopic repair: sugar-tong splint for 2 weeks, followed by above-
arm Munster cast for 4 weeks, followed by Munster splint until 45 degrees of
nontender pronation and supination was achieved, and then volar resting
wrist splint until full rotation achieved.
■ Activity modification:
■ After splinting, gentle active range of motion of the wrist is encouraged.
Gentle activities of daily living are resumed, but lifting is limited to less than
10 lb based on any repairs that have been performed.
■ Wrist capsule stiffness is a frequent complaint in postarthroscopy patients,
and patient education is critical regarding active range of motion and duration
of expected stiffness.
■ Gradual strengthening should be encouraged, and involvement of certified
hand therapists can optimize recovery.
OUTCOMES
■ TFCC tear diagnosis.
■ A recent retrospective review of 908 patients with arthroscopic-confirmed
TFCC tears illustrated only a 0.53 to 0.55 positive predictive value of clinical
tests and a positive predictive value of MRI of 0.41 to 0.44 in diagnosing a
TFCC tear. Arthroscopy is the standard for diagnosing and staging TFCC
tears.6
■ Scapholunate ligament treatment
■ In partial SL ligament tears, 85% treated by arthroscopic debridement have
reported satisfactory improvement in symptoms. Only 67% with complete
tear reported satisfactory outcomes with debridement alone.7

■ Arthroscopic reduction and K-wire pinning of SL instability is most
beneficial in patients with instability for less than 3 months and a gap of 3 mm
or less in the SL interval (83% symptomatic relief compared to 53%
symptomatic relief if instability was present for longer, or a greater than 3-
mm SL interval gap were present).8
■ Lunotriquetral ligament treatment.
■ In a small series of LT ligament tears treated with arthroscopic debridement
alone, 100% (six patients) with partial injury reported resolution of symptoms
after debridement, and 78% (nine patients) with complete tear reported
symptom resolution.7
■ Wrist ganglion treatment
■ A systematic review of arthroscopically treatment volar wrist ganglions
reported a recurrent rate of 0% to 20% (mean 6%) and a 7% complication
rate. A higher complication rate was reported for arthroscopic treated of volar
wrist ganglia in the midcarpal joint as the procedure is technically more
difficult.9
■ Fracture-reduction assistance
■ In case series of acute and nonunion scaphoid fractures, arthroscopy has been
shown to aid in the assessment of fracture reduction.10 In acute scaphoid
fractures, one series illustrated median time to union of 62 days and average
return to work 21 days after surgery.10
■ A randomized-control trial of arthroscopically vs fluoroscopically assisted
reduction of intra-articular distal radius fractures treated with volar locking
plate illustrated no statistical difference in radiographic or functional
outcomes, including range of motion (ROM) and disabilities of the arm,
shoulder, and hand (DASH) scores, between the two groups.11
COMPLICATIONS
■ Most complications are related to injury of the dorsal cutaneous sensory nerve
branches, particularly:
■ Superficial radial nerve in the 1-2 portal
■ Dorsal cutaneous branch of the ulnar nerve from the 6U portal
■ Palmar cutaneous branch of ulnar nerve from volar ulnar portal
■ Ulnar neurovascular bundle injury from over-retraction or poor portal
placement
■ Chondral injury from trochar insertion

■ Venous bleeding
■ Loss of wrist motion (particularly forearm supination)
■ Fluid extravasation
■ Infection
■ Minor contact burns at the portals and dorsal skin by the full-radius resector
and bur may occur in dry arthroscopy
■ Meticulous technique is essential to reduce the above complications.
REFERENCES
1. Wolff JM, Dukas A, Pensak M. Advances in wrist arthroscopy. J Am Acad
Orthop Surg. 2012;20:725-734.
2. Smith TO, Drew BT, Toma AP, Chojnoswki AJ. The diagnostic accuracy of
X-ray arthrography for triangular fibrocartilaginous complex injury: a
systematic review and meta-analysis. J Hand Surg Eur. 2012;37:879-887.
3. Jones CM, Grasu BL, Murphy MS. Dry wrist arthroscopy. J Hand Surg [Am].
2015;40:388-390.
4. Palmer AK. Triangular fibrocartilage complex lesions: a classification. J Hand
Surg Am. 1989;14:594-606.
5. Geissler WB, Freeland AE, Savoie FH, et al. Intracarpal soft-tissue lesions
associated with an intra-articular fracture of the distal end of the radius. J Bone
Joint Surg. 1996;78:357-365.
6. Schmauss D, Pohlmann S, Lohmeyer JA, et al. Clinical tests and magnetic
resonance imaging have limited diagnostic value for triangular
fibrocartilaginous complex lesions. Arch Orthop Trauma Surg.
2016;136(6):873-880.
7. Weiss AP, Sachar K, Lowacki KA. Arthroscopic management of partial
scapholunate and lunotriquetral injuries of the wrist. J Hand Surg [Am].
1997;22:344-349.
8. Whipple TL. The role of arthroscopy in the treatment of scapholunate
instability. Hand Clin. 1995;11:37-40.
9. Fernandes CH, Miranda CD, dos Santos JB, Faloppa F. A systematic review
of complications and recurrence rate of arthroscopic resection of volar wrist
ganglion. Hand Surg. 2014;19:475-480.
10. Slutsky DJ, Trevare J. Use of arthroscopy for the treatment of scaphoid
fractures. Hand Clin. 2014;30:91-103.
11. Yamazaki H, Uchiyama S, Komatsu M, et al. Arthroscopic assistance does
not improve the functional or radiographic outcome of unstable intra-articular

distal radial fractures treated with a volar locking plate. Bone Joint J.
2015;97B:957-962.

15
CHAPTER
Ligament Reconstruction for
Chronic Scapholunate
Dissociation
Mark Morris and Kevin C. Chung
DEFINITION
■ Scapholunate instability is the most common form of carpal instability.
■ Injury to the scapholunate interosseous ligament (SLIL) and subsequent dorsal
intercalated segmental instability (DISI) results in scapholunate advanced
collapse (SLAC) if untreated.1
■ Chronic tears generally require reconstruction rather than primary repair.
■ Static vs dynamic instability2
■ Static instability: Any or all of the radiographic changes discussed below in
the imaging section, seen on plain radiographs
■ Dynamic instability: Normal plain radiographs, but with stress radiographs,
any or all radiographic changes are seen.
■ Fixed vs reducible deformity
■ Fixed deformity: Static radiographic changes are not passively correctible.
■ Reducible deformity: Static radiographic changes are passively correctible.
ANATOMY
■ The lunate, or the intercalated segment, is connected to the scaphoid via the
scapholunate ligament and to the triquetrum via the lunotriquetral ligament.
■ The scaphoid is inclined to flex, whereas the triquetrum is inclined to extend.
Disruption in either ligamentous complex results in intercalated instability.
■ The scapholunate ligament is a C-shaped structure that connects the dorsal,
proximal, and volar surfaces of the scaphoid and lunate.3 It has three portions
(FIG 1):
■ Dorsal portion

• 2 to 3 mm thick
• Greatest rupture strength and is responsible for rotational and translational
restraint
■ Proximal membranous portion
■ Volar portion
• 1 mm thick
PATHOGENESIS
■ SLIL disruption occurs when the wrist is forced into extension, supination, and
ulnar deviation.4
■ SLIL injuries range from sprains, partial tears, or complete tears.
■ The SLIL usually fails at the scaphoid bone-ligament interface.
NATURAL HISTORY
■ With complete rupture of the SLIL, the scaphoid flexes and the lunate is now
free to be pulled into extension either by the triquetrum5 or because of its own
natural tendency due to its shape.6 This produces the DISI pattern.
■ Left untreated, the DISI deformity results in abnormal radiocarpal contact.
■ Flexion and hypermobility of the scaphoid leads to a predictable pattern of
degenerative changes, resulting in SLAC wrist.
■ SLAC was initially described in three stages but has been more recently
described in five stages of degenerative changes:
■ Stage I: radioscaphoid
■ Stage II: scaphocapitate
■ Stage III: lunocapitate
■ Stage IV: triquetrohamate
■ Stage V: radiolunate
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Patients complain of radial-sided wrist pain exacerbated by loading activities,
weak grip, swelling, and loss of wrist range of motion.
■ Tenderness to palpation in the anatomic snuffbox or over the scapholunate
interval, just distal to Lister tubercle
■ Pain with extremes of wrist extension and radial deviation
■ Diminished grip strength on examination
■ Watson scaphoid shift test may be positive in scapholunate dissociation (FIG
2).7

■ The examiner places his or her thumb over the scaphoid tuberosity and the
fingers over the dorsal radius. The other hand is used to move the wrist
passively from ulnar to radial deviation. The scaphoid is extended with the
wrist in ulnar deviation and flexed with the wrist in radial deviation. The
examiner applies pressure on the scaphoid tuberosity while moving the wrist
from ulnar to radial deviation. This prevents the scaphoid from flexing. If the
SLIL is completely torn, the proximal pole subluxes dorsally out of the
scaphoid fossa, inducing pain on the dorsoradial aspect of the wrist. When
pressure is released, a clunk may occur. This indicates self-reduction of the
scaphoid back into its normal position.
■ Scapholunate ballottement test may also be positive.
■ The examiner holds the patient’s scaphoid between the thumb and index
finger. The thumb is placed over the tuberosity, and the index finger is placed
over the proximal pole. The thumb and index fingers of other hand are used to
hold the lunate. The examiner attempts to move the scaphoid and lunate in
opposite directions.
■ This test is positive when it elicits pain.
FIG 1 • The scapholunate ligament is a C-shaped

structure that consists of a stronger dorsal portion (2–3
mm thick), a proximal membranous portion, and a volar
ligamentous portion (1 mm thick).
IMAGING
■ Radiographs may demonstrate the following findings suggestive of SLIL
injury:
■ Terry Thomas sign: Scapholunate diastasis of more than 3 mm on standard
PA radiographs (FIG 3A)8
■ Signet ring sign: The presence of a flexed scaphoid on standard PA
radiographs produces a cortical hyperdensity that resembles a signet ring (see
FIG 3A).5
■ Angular changes in the carpal bones
• The normal scapholunate angle ranges from 30 to 60 degrees. An angle over
60 degrees is seen with SLIL injury (FIG 3B).
• The normal capitolunate angle ranges from −15 to 15 degrees. An angle
greater than 15 degrees is seen with SLIL injury.
• The normal radiolunate angle ranges from −10 to 10 degrees. An angle
greater than 10 degrees is seen with SLIL injury.

FIG 3 • A. PA radiograph of the wrist showing diastasis
of the scapholunate interval (arrow). A signet ring sign
can also be seen here (circled), which is produced
when the scaphoid is flexed so the tubercle is
superimposed on the waist of the scaphoid. B. The
scapholunate angle is formed by the intersection of the
scaphoid axis (a line drawn between the most palmar
point of the distal pole and the most palmar point of the
proximal pole) and the lunate axis (a line drawn
perpendicular to a line drawn between the most distal
palmar and dorsal points of the lunate). A scapholunate
angle greater than 70 degrees indicates a DISI
deformity.
■ Quadrangular lunate: The lunate appears rectangular on standard PA
radiographs as it moves into extension.

■ Disruption of Gilula lines as the relationship of the proximal carpal row is
lost.
■ The presence of degenerative changes involving the radiocarpal or midcarpal
joints is a contraindication for ligament reconstruction.
FIG 2 • Watson scaphoid shift test. The examiner uses
his or her thumb to apply pressure over the scaphoid
tuberosity while using the other hand to move the wrist
from ulnar to radial deviation.
■ MRI can be performed to identify tears when radiographs are normal.
■ The sensitivity of a 3-T MRI ranges from 65% to 89% for complete
scapholunate ligament tears. The sensitivity of MRA is reported to be 85% to
100%.
■ The sensitivity of both MRI and MRA is poor for partial ligament tears.8
DIFFERENTIAL DIAGNOSIS
■ Partial SLIL tear

■ Radiocarpal arthritis
■ Scaphoid fracture
■ Keinbock disease
NONOPERATIVE MANAGEMENT
■ Nonoperative management of complete SLIL tear is unsuccessful and reliably
results in radiocarpal and midcarpal degenerative changes.
SURGICAL MANAGEMENT
■ Direct repair is rarely an option for a chronic SLIL tear.
■ Capsulodesis is an option for dynamic scapholunate dissociation if secondary
stabilizers are intact and there is no cartilage degeneration. Capsulodesis is not
indicated in the case of static scapholunate dissociation.
■ Ligament reconstruction
Preoperative Planning
■ The surgeon can consider diagnostic wrist arthroscopy prior to ligament
reconstruction. This will help to better characterize the articular surfaces of the
carpal bones, as well as to better delineate the degree of ligament injury.
Positioning
■ The patient is positioned supine on the operating table. The operative
extremity is draped out on a hand table.
■ We prefer to use regional anesthesia for this operation. General anesthesia can
also be used.
■ A tourniquet is applied.
■ An examination under anesthesia is performed. A Watson shift test is done to
feel for a clunk.
Approach
■ Volar and dorsal incisions are made.
■ The volar incisions are used to harvest the flexor carpi radialis (FCR) graft.
■ The dorsal incision is used for most of the reconstruction.
T E C H N I Q U E S

■ Exposure
■ Dorsal
■ An 8-cm longitudinal dorsal wrist incision is centered over Lister tubercle
(TECH FIG 1A).
■ The extensor retinaculum over the third compartment is opened, and the
extensor pollicis longus (EPL) is retracted radially.
■ The dorsal wrist capsule is opened through a longitudinal incision to
expose the scapholunate interval (TECH FIG 1B).
TECH FIG 1 • A. Dorsal wrist incision. B. The
scapholunate interval is exposed. The Freer elevator
in this image is in the scapholunate interval. C. Volar
wrist incisions.
■ Volar
■ Three 1-cm incisions are made along the course of the flexor carpi radialis
(FCR; TECH FIG 1C).
■ An oblique Wagner incision is made over the scaphoid tuberosity.
■ The radial sensory nerve is at risk with this incision and must be preserved.
■ The scar tissue is excised between the scaphoid and lunate.

■ Reduction of Scaphoid and Lunate and Creation of
a Bone Tunnel
■ Two 0.062-inch K-wires are placed dorsally into the scaphoid and lunate.
The K-wires are used as joysticks to aid in reduction (TECH FIG 2).
■ Threaded wires may provide better purchase of the scaphoid and lunate so
joystick wires do not pull out.
■ Wires must be drilled away from the anticipated tunnel for the planned
ligament reconstruction.
■ To correct the DISI deformity, the surgeon must extend the scaphoid and flex
the lunate. Direct the scaphoid wire proximally and the lunate wire distally.
■ To create a bone tunnel, a K-wire is passed from the scaphoid tuberosity to
the dorsum of the scaphoid along its axis.
■ A cannulated 2.7-mm drill is passed over the wire from the dorsum to the
palmar side.
Harvesting and Passing a Strip of Distally Based FCR Tendon
■ A distally based 3-mm-wide by 8- to 10-cm-long strip of FCR tendon is
harvested from the radial aspect of the tendon (TECH FIG 3).

TECH FIG 2 • A. K-wires are used for reduction of the
scaphoid and lunate. B. The scaphoid wire is directed
proximally to extend the scaphoid (solid arrow),
whereas the lunate wire is directed distally to flex the
lunate (dashed arrow).

TECH FIG 3 • The distally based FCR tendon graft is
harvested and passed though the scaphoid tunnel.
■ The FCR tendon rotates 90 degrees within the sheath at the wrist. It is
important to follow the fibers so the tendon is not inadvertently transected.
Do not slide the scissors through the tendon fibers; cut along the fibers to
maintain the integrity of the tendon.
■ A grasping suture is placed at the cut end of the distally based FCR tendon
and is then passed through the scaphoid tunnel from volar to dorsal.
■ Forcing a wide strip of FCR through the scaphoid tunnel can fracture the
scaphoid. It is better to harvest a narrow strip of FCR tendon.
Reduction of the Scapholunate Interval
■ The scapholunate interval is reduced using the joystick K-wires. The K-
wires can only correct the flexion-extension deformities of the scaphoid and
lunate. A bone reduction clamp or towel clip is used to reduce the gap
between the two bones.
■ Reduction is maintained by passing new K-wires across the scapholunate
and scaphocapitate joints.
■ Confirm reduction of the scapholunate interval with fluoroscopy. Once this
is done, the joystick K-wires can be removed.
Securing the FCR to the Lunate and Closure
■ A bur is used to make a shallow trough on the dorsum of the lunate.
■ The FCR tendon graft is secured to the midportion of the trough using a 1.8-

mm bone anchor suture (TECH FIG 4A).
■ The remaining portion of the tendon graft is passed through a slit in the
distal portion of the dorsal radiotriquetral ligament and is sutured back to
itself over the lunate (TECH FIG 4B).
■ The dorsal capsule is first repaired using 3-0 Ethibond suture.
■ The tourniquet is released and hemostasis is obtained.
■ The EPL is transposed dorsal to the extensor retinaculum to avoid ischemic
rupture that may occur due to postoperative swelling in the EPL sheath. The
extensor retinaculum is also closed using 3-0 Ethibond suture.
■ Skin is closed using 4-0 nylon suture.
TECH FIG 4 • A. The FCR tendon is secured into the
trough in the lunate using a 1.8-mm bone anchor
suture. B. The remaining FCR tendon graft is sutured
back over itself.
PEARLS AND PITFALLS
Technique
■ Some authors recommend a ligament-sparing capsulotomy to expose
the scapholunate interval. To do so, the capsular incision is made in

line with the fibers of the intercarpal and radiocarpal ligaments, and a
trapezoid capsular flap is raised.
■ The superficial radial nerve and palmar cutaneous branch of the
median nerve are at risk with the volar portion of the surgery and
should be identified and protected.
■ The FCR tendon can be inadvertently transected as it rotates 90
degrees at the wrist. Be careful and follow the fibers rather than blindly
sliding the scissors to harvest the graft.
■ The scaphoid can be fractured if the surgeon attempts to force a wide
graft through the tunnel. The tendon graft should be approximately 3
mm wide.
■ K-wires are cut under the skin to avoid pin tract infection. The K-wires
are removed in the operating room in 8 wk.
Therapy
■ In therapy, initial restriction of radial and ulnar deviation lessens the
force on the SLIL ligament reconstruction.
POSTOPERATIVE CARE
■ The patient is placed in a volar wrist splint postoperatively.
■ The splint and operative dressings are taken down after 10 to 14 days, and the
wound is examined. Sutures are removed at this time.
■ The patient will remain splinted for 8 weeks.
■ After 8 weeks of splinting, the patient is transitioned to a removable volar
wrist splint for an additional 4 weeks. Gentle active wrist range of motion is
started at this time. We do not send the patient to therapy because injudicious
stressing of the wrist to get more motion will disrupt the reconstruction. Our
goal is painless motion and whatever motion the patient can achieve is the
suitable motion. This expectation must be presented to the patient before
surgery; we inform the patient that there is no good wrist operation and all
wrist operations trade pain relief for decreased wrist motion.
■ Initial restriction of radial and ulnar deviation lessens the force on the
ligament reconstruction.
■ K-wires are removed 6 to 8 weeks after surgery.
OUTCOMES
■ Most patients will have mild to no pain after initial recovery from surgery.9–12
■ Most patients feel subjective improvement and would have the operation
again.9
■ Studies have shown a slight loss of wrist motion after surgery (FIG 4).

■ Total wrist motion averaged 85% of contralateral (uninjured) wrists in one
study at an average of 10 years of follow-up.11
■ A more recent study of 20 patients with a mean follow-up of 24 months
showed that wrist flexion was reduced by a mean of 19 degrees, and extension
was decreased by a mean of 14 degrees.12
FIG 4 • Five-month postoperative clinical photographs
after scapholunate ligament reconstruction with FCR
tendon autograft. This patient demonstrates a minor
loss of motion of the operative (left) wrist, as is to be
expected. This loss of motion did not cause him any
discomfort or disability. He was very satisfied with his
outcome.
■ Radial and ulnar wrist deviation has been shown to be 68% and 86% of
contralateral wrists, respectively, in one study and equal to contralateral in
another.9,10
■ Grip strength has been shown to be 78% to 85% of contralateral (uninjured)
strength after a modified Brunelli reconstruction.10–12
■ Radiographic parameters improve after surgery. In one study, the average

preoperative scapholunate gap was 5.1 mm, which was reduced to 2.4 mm at
surgery and was 2.8 mm at final follow-up at an average of 10 years.11
Scapholunate angle has been shown to improve to within normal limits
immediately after surgery but may increase again after longer follow-up.10–12
■ Most patients avoid degenerative changes of the wrist.10–12
COMPLICATIONS
■ Damage to superficial radial nerve or the palmar cutaneous branch of the
median nerve.
■ Scar tenderness.9
■ Complex regional pain syndrome.9,10
■ SLAC wrist occurred in 1 out of 19 patients in one study with a mean of 37
months of follow-up,10 1 out of 8 in another study with a mean of 10 years of
follow-up,11 and 3 out of 20 in another study with a mean of 24 months of
follow-up.12
■ Ligament reconstruction should not be performed in patients who already
have degenerative changes on radiographs.
REFERENCES
1. Watson K, Ballet FL. The SLAC wrist: scapholunate advanced collapse
pattern of degenerative arthritis. J Hand Surg Am. 1984;9:358-365.
2. Taleisnik J. Post-traumatic carpal instability. Clin Orthop Relat Res.
1980;149:73-82.
3. Berger RA. The gross and histologic anatomy of the scapholunate
interosseous ligament. J Hand Surg Am. 1996;21A:170-178.
4. Mayfield JK, Johnson RP, Kilcoyne RK. Carpal dislocations: pathomechanics
and progressive perilunar instability. J Hand Surg Am. 1980;5A:226-241.
5. Taleisnik J. Current concepts review. Carpal instability. J Bone Joint Surg Am.
1988;70:1262-1268.
6. Kaur JM. Functional anatomy of the wrist. Clin Orthop Relat Res.
1980;149:9-20.
7. Watson HK, Ashmead D, Makhlouf MV. Examination of the scaphoid. J Hand
Surg Am. 1988;13(5):657-660.
8. Ramamurthy NK, Chojnowski AJ, Toms AP. Imaging in carpal instability. J
Hand Surg Eur. 2016;41E(1):22-34.
9. Van den Abbeele KLS, Loh YC, Stanley JK, Trail IA. Early results of a
modified Brunelli procedure for scapholunate instability. J Hand Surg Br.

1998;23:258-261.
10. Chabas JF, Gay A, Valenti D, et al. Results of the modified Brunelli tenodesis
for treatment of scapholunate instability: a retrospective study of 19 patients. J
Hand Surg Am. 2008;33:1469-1477.
11. Nienstedt F. Treatment of static scapholunate instability with modified
Brunelli tenodesis: results over 10 years. J Hand Surg Am. 2013;38A:887-892.
12. Elgammal A, Lukas B. Mid-term results of ligament tenodesis in treatment of
scapholunate dissociation: a retrospective study of 20 patients. J Hand Surg Br.
2016;41E(1)56-63.

16
CHAPTER
Lunotriquetral Ligament
Reconstruction Using a Slip
of the Extensor Carpi
Ulnaris Tendon
Mark Morris and Kevin C. Chung
DEFINITION
■ Isolated injury to the lunotriquetral (LT) ligament is less common than injury
to the scapholunate (SL) ligament.
■ LT ligament injury can be found in isolation or in combination with other
injuries, such as in the case of a perilunate dislocation.
■ The mechanism of LT ligament injury is debated but may be secondary to a
dorsally applied force to a palmar-flexed wrist. Perilunate dislocation is
thought to occur when the wrist is forced into hyperextension and ulnar
deviation.1
■ LT disruption can be the result of acute trauma or secondary to degenerative or
inflammatory conditions.
■ LT injury ranges from partial tears to complete dissociation. Partial tears or
attenuation of the ligament are more common and result in dynamic instability,
whereas complete dissociation leads to static collapse.
■ Volar intercalated segment instability (VISI) occurs after complete disruption
of the LT ligament, dorsal radiotriquetral ligament, and volar radiolunate
ligament.
■ VISI may occasionally be seen in uninjured wrists, in contrast to dorsal
intercalated segment instability (DISI), which is always pathologic.
ANATOMY
■ The LT ligament is C-shaped, consisting of dorsal, proximal membranous, and

palmar portions (FIG 1). In contrast to the SL ligament where the dorsal
portion is thickest and strongest, the palmar region of the LT ligament is the
thickest and strongest portion.2,3
■ Secondary stabilizers of the LT joint include the ulnocarpal (ulnolunate,
ulnocapitate, and ulnotriquetral), midcarpal (triquetrohamate and
triquetrocapitate), and dorsal carpal (dorsal intercarpal and radiotriquetral)
ligaments (FIG 2).
■ Complete tear of only the LT ligament will not result in VISI deformity
because the secondary stabilizers maintain the lunate and triquetrum in
position.
■ The scaphoid has a tendency to flex, whereas the triquetrum has a tendency to
extend. The lunate, or intercalated segment, is balanced by these two opposing
forces.
PATHOGENESIS
■ Isolated LT tear is thought to occur when a dorsally applied force is applied to
a palmar-flexed wrist. This force causes the dorsal LT fibers to tear. The volar
radiolunate ligaments remain intact and tether the proximal lunate on the volar
side, leading to palmar flexion.
■ Reverse perilunate injuries occur from falling on an outstretched hand with the
wrist extended, pronated, and radially deviated. This mechanism can also result
in an isolated LT tear, followed by lunocapitate dislocation, and then SL
dissociation (FIG 3A).4
■ Perilunate injuries occur when the wrist is forced into hyperextension and
ulnar deviation. Mayfield describes four stages of perilunate injury (FIG 3B).1
LT injuries occur in Mayfield III and IV perilunate injuries.
■ Inflammatory arthritis or degenerative LT lesions may also lead to instability.
NATURAL HISTORY
■ The natural history of LT injuries has not been clearly defined; however, they
may lead to degenerative changes of the wrist.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Patients present with ulnar-sided wrist pain.
■ Patients may or may not report a history of trauma.
■ Patients may have tenderness to palpation over the dorsal LT joint.

FIG 1 • The lunotriquetral ligament is C-shaped,
consisting of palmar, dorsal, and proximal membranous
portions. The palmar portion is the thickest and
strongest portion of the ligament.

FIG 2 • A. Dorsal wrist ligaments. The important dorsal
secondary stabilizers of the lunotriquetral joint are the
dorsal intercarpal and dorsal radiotriquetral (also known
as dorsal radiocarpal) ligaments. B. Volar wrist
ligaments. The important volar secondary stabilizers of
the lunotriquetral joint are the short and long radiolunate
ligaments, the ulnolunate ligament, the ulnocapitate
ligament, and the ulnotriquetral ligament.
■ LT compression test: Radially directed pressure is applied over the triquetrum.
This may elicit pain in patients with LT instability (FIG 4A).
■ LT ballottement test: The lunate is stabilized with the thumb and index finger
of one of the examiner’s hands. The other hand is used to displace the
triquetrum and pisiform dorsally and palmarly. Pain, crepitus, and joint laxity
are seen in patients with LT instability (FIG 4B).
■ Ulnar deviation with pronation and axial compression may elicit instability
and a painful clunk.
■ Limited range of wrist motion
■ Diminished grip strength
IMAGING
■ A PA radiograph may show a break in Gilula lines. There is often a step-off
between the lunate and triquetrum.

■ It is rare to see a gap in the LT interval on radiographs with LT injuries, in
contrast to SL injuries where a gap is seen. Plain radiographs may be normal
(FIG 5).
FIG 3 • A. Reverse perilunate injuries start on the ulnar
side of the wrist starting with an isolated LT tear,
followed by lunocapitate dislocation, and then
scapholunate dissociation. B. Mayfield’s four stages of
perilunate injury. Stage 1: Disruption of scapholunate
ligament or scaphoid fracture. Stage 2: Lunocapitate
dislocation. Stage 3: Lunotriquetral dissociation or
triquetrum fracture. Stage 4: Lunate dislocation.

FIG 4 • A. Lunotriquetral compression test. The
examiner applies radially directed pressure over the
triquetrum. B. Lunotriquetral ballottement test. The
lunate is stabilized with the thumb and index finger of
one of the examiner’s hands. The other hand is used to
displace the triquetrum and pisiform dorsally and
palmarly.
■ A lateral radiograph may show a VISI deformity, marked by volar tilting of the
lunate. This indicates injury to the LT injury along with injury to the dorsal
radiotriquetral ligament (FIG 6).
■ The SL angle is less than 30 degrees with a VISI deformity.
■ The capitolunate angle increases to over 15 degrees with a VISI deformity.
■ MRI is not reliable for imaging of LT ligament injuries.
DIFFERENTIAL DIAGNOSIS
■ Ulnar impaction syndrome
■ Distal radioulnar joint instability
■ Extensor carpi ulnaris subluxation

■ Triangular fibrocartilage complex injuries
■ Pisotriquetral arthritis
■ Hook of hamate fracture
FIG 5 • PA, oblique, and lateral radiographs of a patient
with a lunotriquetral injury. There is no apparent
widening of the lunotriquetral interval or VISI deformity
seen here; however, a lunotriquetral ligament tear was
found on wrist arthroscopy after the patient failed
nonoperative management.

FIG 6 • The VISI deformity is marked by the lunate in a
flexed position, which decreases the scapholunate
angle and increases the capitolunate angle.
NONOPERATIVE MANAGEMENT
■ The appropriate management of an acute LT injury is immobilization in a cast
for 8 to 12 weeks. Patients who present with subacute or chronic LT injuries
should also be treated first with immobilization, but the timing is less well-
defined and can be determined by the patient’s symptoms during
immobilization.5
■ Midcarpal injections with local anesthetic and corticosteroids may be a helpful
adjunct to immobilization.
SURGICAL MANAGEMENT
■ Surgical management is indicated in patients with symptomatic LT

dissociation that is not relieved by nonoperative management.
■ The goal of surgery is to restore stability to the proximal carpal row and to
realign the lunocapitate axis.
FIG 7 • A dorsal wrist incision is used, centered
between the fourth and fifth compartments.
■ Ligament reconstruction should be reserved for patients without arthritic
changes.
■ If degenerative changes are already present, the surgeon should consider
arthrodesis or proximal row carpectomy.
Preoperative Planning
■ The surgeon can consider diagnostic wrist arthroscopy prior to ligament
reconstruction. This will help to better characterize the articular surfaces of the
carpal bones, as well as to better delineate the degree of ligament injury.
Positioning
■ The patient is positioned supine on the operating table. The operative
extremity is draped out on a hand table.
■ We prefer to use regional anesthesia for this operation. General anesthesia can
also be used.
■ A tourniquet is applied.
■ An examination under anesthesia is performed to evaluate for a clunk. The
distal radioulnar joint can be assessed under anesthesia as well.

Approach
■ A 6-cm longitudinal incision is used, centered over the dorsal wrist between
the fourth and fifth compartments (FIG 7).
■ Alternatively, two incisions can be used—one incision over the dorsal wrist
joint, and another proximally over the ECU tendon harvest site.
T E C H N I Q U E S
■ Exposure and Tendon Harvest
■ A longitudinal skin incision is centered over the dorsal wrist, between the
fourth and fifth compartments.
■ The wrist capsule is incised longitudinally (TECH FIG 1A,B). The LT
interval should now be visible (TECH FIG 1C,D).
■ Excise scar tissue from between the lunate and triquetrum.
■ The ECU tendon is identified in the proximal portion of the incision.
■ A distally based slip of ECU tendon is harvested from the radial aspect of the
tendon (TECH FIG 1E,F).
■ The tendon graft should be 3 mm wide by 8 to 10 cm long.
■ The strip of tendon graft is dissected to its insertion at the base of the small
finger metacarpal.

TECH FIG 1 • A,B. Longitudinal incision of the wrist
capsule. C,D. The lunotriquetral interval is shown here
with a Freer elevator. The lunotriquetral ligament here
is ruptured. E. The intact ECU tendon (arrow). F. A 3-
mm strip of distally based ECU tendon is harvested.
■ Reduction of the Lunate and Triquetrum and

Creation of Bone Tunnels
■ Two 0.062-in. Kirschner wires (K-wires) are inserted into the dorsal lunate
and triquetrum to be used as joysticks for reduction (TECH FIG 2A). Be
sure to keep the K-wires out of the way of the planned tunnels in each bone.
■ To correct the VISI deformity, the lunate is extended by retracting the lunate
K-wire proximally and the triquetrum is flexed by retracting the triquetral K-
wire distally.
■ To create the bone tunnels, a K-wire is placed in the triquetrum from the
distal, dorsal, ulnar aspect toward the proximal, palmar, radial corner. Once
acceptable placement is confirmed, a 2.5-mm cannulated drill is used to
create a bone tunnel in the triquetrum over the K-wire (TECH FIG 2B,C).
■ The lunate bone tunnel is then created in similar fashion by placing a K-wire
from the distal, dorsal, and radial corner of the lunate to the proximal, palmar,
and ulnar corner. A cannulated drill is again used over the K-wire to form the
tunnel.
■ The tunnels should converge at the volar margin of the LT joint and should
remain extra-articular.

TECH FIG 2 • A. Joystick K-wires are placed into the
triquetrum and lunate. The arrows show the direction
of retraction required to reduce the VISI deformity. B.
A bone tunnel is created in the triquetrum (T) using a
cannulated drill. C. A microcurette is used to clear
cartilage remnants at the exit sites of the tunnels.
■ Passing and Securing the ECU Tendon Graft
■ The tendon is passed through the bone tunnels using a wire or suture. First
pass the tendon from the dorsum of the triquetrum to the LT interval and then
from the LT interval to the dorsum of the lunate (TECH FIG 3A).
■ Alternatively, after passing the graft through the triquetrum, a small bone
anchor can be used to secure the tendon graft to the lunate (TECH FIG

3B,C). The VISI deformity must be corrected with the joystick K-wires
prior to fixation with an anchor.
■ Next, the ECU graft is secured to itself over the remnant of the LT ligament.

TECH FIG 3 • A. Bone tunnels are made through the
triquetrum and lunate. A wire or suture (pictured) is
used to feed the graft through the bone tunnels. B,C.
A mini-Mitek anchor can be used to fix the graft to the
lunate. D,E. One or two K-wires are inserted to hold
the reduction of the lunotriquetral joint. Here, an
additional wire was placed through the triquetrum into
the hamate and capitellum. F. After passing the
tendon graft through the triquetrum and lunate, the
free end is sutured back to itself.

■ First, the VISI deformity is corrected as described earlier with the joystick
K-wires.
■ The corrected position is held with a third K-wire passed through the
triquetrum and lunate (TECH FIG 3D,E). The triquetrum should also be
pinned to the capitate to fixate the reduced construct; otherwise, the
triquetrum may rotate around the single K-wire to lose the reduction.
■ The end of the tendon graft is then sutured back to itself using 3-0 Ethibond
sutures (TECH FIG 3F).
■ Closure
■ The wrist capsule is closed tightly with 3-0 Ethibond suture.
■ The extensor retinaculum over the fourth and fifth compartments is closed
using 3-0 Ethibond suture.
■ The joystick K-wires are removed at this time.
■ The K-wire traversing the LT joint is left in place and is cut deep to the skin.
This is done to avoid pin tract infections from a pin that will be left in place.
PEARLS AND PITFALLS
Technique
■ Branches of the dorsal ulnar sensory nerve should be protected.
The dorsal sensory branch of the ulnar nerve arises 8 cm proximal
to the pisiform and passes dorsal to the FCU and pierces the fascia
5 cm proximal to the pisiform. It reaches the dorsal hand in close
proximity to the ulnar styloid process.
■ The ECU tendon graft should not be more than 3 mm wide. If it is
too wide, it will be difficult to pass through the drill holes in the
lunate and triquetrum.
■ Joystick K-wires are used to correct the VISI deformity. The
lunate wire is placed obliquely from a distal to proximal direction,
and the triquetral wire is placed from an oblique proximal to distal
direction. The VISI deformity is corrected by making both wires
perpendicular to the axis of the forearm.
■ An alternative technique to drilling bone tunnels is to use a sharp
curved awl. This is less traumatic and may help to avoid fracturing
the carpal bones.

■ Ulnar shortening osteotomy may be performed at the same time as
LT ligament reconstruction in a patient with concomitant
ulnocarpal abutment.
Postoperative
■ Pain is significantly improved in most patients after this
procedure.
Therapy
■ Do not be too aggressive with therapy or the repair can fail. Long-
term satisfaction is high even though patients do typically lose
some wrist range of motion.
POSTOPERATIVE CARE
■ The patient is placed in a volar wrist splint immediately postoperatively.
■ Incisions are examined and sutures are removed after 10 to 14 days.
■ The patient is kept in a volar wrist splint for 8 weeks.
■ K-wires are removed after 8 weeks.
■ The patient can start gentle range of motion exercises after K-wires are
removed. Wrist stiffness is common (FIG 8).

FIG 8 • Six-month follow-up after lunotriquetral ligament
reconstruction. Although the patient lost some wrist
range of motion, he was satisfied with his result.
OUTCOMES
■ Shin et al.6 demonstrated that patients who had LT ligament reconstruction had
lower reoperation rates than did patients treated with direct repair or
arthrodesis.
■ Shahane et al.7 studied 46 patients who underwent LT ligament reconstruction
with ECU tendon. After a mean of 19 months of follow-up, 19 patients (41%)
had excellent outcomes, 10 (22%) had good outcomes, 11 (24%) had
satisfactory outcomes, and 6 (13%) had poor outcomes based on Mayo wrist
scores. Forty of 46 patients said that they had substantially improved and
would undergo the operation again.
COMPLICATIONS
■ Injury to the dorsal branch of the ulnar nerve
■ Pisotriquetral pain
■ Reflex sympathetic dystrophy
■ Residual instability
REFERENCES
1. Mayfield JK, Johnson RP, Kilcoyne RK. Carpal dislocations: pathomechanics
and progressive perilunar instability. J Hand Surg [Am]. 1980;5(3):226-241.
2. Berger RA. The gross and histologic anatomy of the scapholunate
interosseous ligament. J Hand Surg [Am]. 1996;21A:170-178.
3. Ritt MJ, Bishop AT, Berger RA, et al. Lunotriquetral ligament properties: a
comparison of three anatomic subregions. J Hand Surg [Am]. 1998;23A:425-
431.
4. Murray PM, Palmer CG, Shin AY. The mechanism of ulnar-sided perilunate
instability of the wrist: a cadaveric study and 6 clinical cases. J Hand Surg
[Am]. 2012;37(4):721-728.
5. Wagner ER, Elhassan BT, Rizzo M. Diagnosis and treatment of chronic
lunotriquetral ligament injuries. Hand Clin. 2015;31:477-486.
6. Shin AY, Weinstein LP, Berger RA, Bishop AT. Treatment of isolated injuries
of the lunotriquetral ligament in comparison of arthrodesis, ligament

reconstruction, and ligament repair. J Bone Joint Surg Br. 2001;83:1023-1028.
7. Shahane SA, Trail IA, Takwale VJ, et al. Tenodesis of the extensor carpi
ulnaris for chronic, post traumatic lunotriquetral instability. J Bone Joint Surg
Br. 2005;87:1512-1515.

17
CHAPTER
Fixation of Acute Scaphoid
Fractures
Ketan Sharma, James T. W. Saunders, and Amy M. Moore
DEFINITION
■ The scaphoid is the most commonly fractured bone of the carpus.
■ Acute scaphoid fractures are defined as occurring within 3 to 4 weeks of the
inciting event.
■ Displaced scaphoid fractures are defined as exhibiting more than 1 mm
displacement or more than 10 degrees angulation.
■ Operative treatment of acute scaphoid fractures remains challenging due to the
complex geometry and tenuous blood supply of the scaphoid itself.
■ Herbert’s system classifies fractures into four types1:
■ Type A—stable and acute
■ Type B—unstable and acute
■ Type C—delayed unions
■ Type D—established nonunion
ANATOMY
■ The scaphoid spans the proximal and distal carpal rows, and serves as an
important dynamic link between the two.
■ The scaphoid articulates with the radius, lunate, capitate, trapezoid, and
trapezium.
■ These numerous articulations mean that over 80% of the surface area of the
scaphoid is covered with cartilage and not periosteum.
■ This characteristic limits both ligamentous structural integrity and vascular
healing potential.
■ This also means the scaphoid heals predominantly through primary bone
healing (intramembranous ossification), which can result in a paucity of

callus formation and weak early union.2
■ The scaphoid bone is divided into three regions: the proximal pole, waist, and
distal pole (or tubercle [FIG 1]).
■ The proximal pole of the scaphoid articulates with the distal radius within the
scaphoid fossa, and is coupled to the neighboring lunate within the proximal
row via the strong scapholunate (SL) ligament.
■ This ligament prevents the scaphoid from falling into a flexed position, and is
crucial for carpal stability.
■ Vascular supply to the scaphoid is provided through two main branches of the
radial artery (FIG 2).
■ The dorsal branch supplies 70% to 80% of the total vascularity, enters at the
dorsal ridge distally, and supplies the entire proximal pole.
FIG 1 • A. PA (B) and lateral radiographs showing
nondisplaced fracture of the scaphoid waist (scaphoid

outlined in yellow; fracture magnified in inset in A). The
scaphoid is divided into three regions (proximal pole,
waist, distal pole) and serves as an important dynamic
link between the proximal and distal carpal rows.
FIG 2 • The scaphoid is supplied by dorsal and volar
branches of the radial artery, which predominantly
distribute to the proximal and distal poles, respectively.
This unique retrograde vasculature has important
implications concerning healing of waist and proximal
pole fractures.

■ The volar branch supplies 20% to 30% of the total vascularity, enters through
the tubercle, and supplies the distal pole and distal tuberosity predominantly.3
■ The proximal pole receives the majority of its blood supply through retrograde
intraosseous vascular flow from these arteries and is therefore susceptible to
avascular necrosis (AVN) when this supply is disrupted by the fracture.
PATHOGENESIS
■ The most common mechanism of injury of the scaphoid is a hyperextension of
the wrist more than 95 degrees, coupled with an ulnar deviation.4
■ A volar tensile force leads to failure and propagation of a fracture through the
body of the scaphoid to the dorsal surface where compression loading occurs.
■ Impingement on the dorsal rim of the distal radius during hyperextension
may also contribute to waist fractures.
■ Proximal pole scaphoid fractures likely occur from dorsal subluxation during
forced hyperextension.
■ Less commonly, hyperflexion and axial loads may also produce scaphoid
fractures.
NATURAL HISTORY
■ The natural history of scaphoid fractures remains integral to treatment strategy.
■ Healing potential is fundamentally a function of fracture potential and
available vascularity.
■ More proximal fractures have poorer blood supply, leading to decreased
healing potential, which can produce nonunion or AVN.
■ Fracture displacement disrupts the blood supply and decreases healing
potential.
■ Fractures displaced more than 1 mm or angulated more than 15 degrees have
an increased risk of nonunion.
■ Displaced or untreated scaphoid nonunions will predictably progress to dorsal
intercalated segmental instability (DISI) type carpal instability, and eventually
scaphoid nonunion advanced collapse (SNAC) arthrosis.
■ In patients with a nonunion, up to 97% will demonstrate arthritic change
within 5 years of the injury.5
■ Risk factors for scaphoid nonunion include delayed treatment, inadequate
immobilization, proximal fractures, comminution, and concomitant carpal
injuries.6