Operative Technique in Plastic Surgery – Kevin C.Chung

palmaris longus tendon graft is passed to the adductor
pollicis.
■ Thumb Stabilization: Split Flexor Pollicis Longus
(FPL) to Extensor Pollicis Longus (EPL) Tenodesis
■ The muscle imbalances of the ulnar paralyzed hand, particularly due to the
loss of the adductor pollicis, result in greater flexion of the IP joint and less
of the MCP. This creates a Z-deformity in about 60% of patients.11
■ A radial incision is made over the proximal phalanx of the thumb.
■ Preserving the oblique pulley, the FPL and EPL are exposed.
■ The radial half of the FPL is released from the distal insertion and weaved
into the EPL (TECH FIG 6).
■ The interphalangeal joint is kept in extension with a 0.045-in. K-wire.
TECH FIG 6 • A. The radial half of the FPL is released
from the rest of the tendon at the insertion site. B. This
radial slip is transferred dorsally. C. Final position after
transfer shows IP joint stabilization.

■ Restoration of Finger Flexion: Flexor Digitorum
Profundus (FDP) Side-to-Side Transfer
■ High ulnar nerve palsy results in paralysis of the ulnar 0.5 of FDP, affecting
motion of the DIP joints of the ring and small fingers and thus grip strength.
■ Side-to-side transfer is an easy way to address this with the median nerve
innervated portion of the muscle.
■ A longitudinal incision is made over the distal third of the forearm.
■ The FDP tendons are identified, deep to the median nerve.
■ The FDP tendons are synchronized to recreate the digital cascade, and one
sutures the long through small finger tendons with two rows of braided
permanent sutures.
PEARLS AND PITFALLS
Preoperative
evaluation
■ Critically assess donor muscle availability and strength.
■ Determine patient goals and potential for additional nerve
recovery.
■ Determine the integrity of the PIP central slip with the Bouvier
maneuver.
Thumb
adduction
■ The thumb may have joint instability that requires additional
procedures such as capsulodesis or arthrodesis.
Addressing
claw deformity
■ Static transfers usually stretch over time and should be reserved
for combined nerve injuries.
■ Transfers must pass volar to the MCP joint to address
hyperextension.
■ Dynamic transfers should be sewn into lateral bands if Bouvier
maneuver is negative.
POSTOPERATIVE CARE
■ The patient is usually splinted with the MCP joints in 60 to 70 degrees of
flexion and the IP joints in full extension (intrinsic plus position) for a total of 4
weeks. Active range of motion exercises are then commenced, with a dorsal
blocking splint at the MCP joint.

■ Passive range of motion is started at 6 weeks. Strengthening is started at 8
weeks for the adductor plasty and 10 weeks for the intrinsic transfers.
■ A knowledgeable hand therapist plays an important role in the surgical
outcomes.
■ Early active range of motion has been advocated by some surgeons, with
quicker recovery and less pain.12,13
OUTCOMES
■ Outcome studies are difficult to compare due to the heterogeneity of the
patient populations.
■ Static reconstructions often stretch. Less than 50% of the hands treated with
capsulodesis see long-term improvement in regard to clawing.14
■ Wrist extensor transfers to the lateral bands restore grip strength most
effectively, with the highest efficacy in those with short-standing paralysis.15
However, the need for tendon grafts and scarring through the interosseous
muscles makes them less favorable.16,17
■ FDS transfers are most efficacious in addressing claw deformity, with minimal
improvement in grip strength.15,18
COMPLICATIONS
■ Complications are more common with the intrinsic transfers due to the delicate
balance in the extensor mechanism.
■ Transfers may be ineffective due to poor tensioning and may need surgical
revision to tighten the insertion.
■ Transfers that are too tight can often be addressed with passive range of
motion exercises to stretch the transfer.
■ Harvest of FDS results in a swan-neck deformity fairly commonly, with the
incidence ranging from 15% to 85%.15,19,20
REFERENCES
1. Riordan DC. Tendon transfers for nerve paralysis of the hand and wrist. Curr
Pract Orthop Surg. 1964;23:17-40.
2. Srinivasan H. Clinical features of paralytic claw fingers. J Bone Joint Surg
Am. 1979;61(7):1060-1063.
3. Goldfarb CA, Stern PJ. Low ulnar nerve palsy. J Am Soc Surg Hand.
2003;3(1):14-26.
4. Wang K, McGlinn EP, Chung KC. A biomechanical and evolutionary

perspective on the function of the lumbrical muscle. J Hand Surg.
2014;39(1):149-155.
5. Mikhail IK. Bone block operation for clawhand. Surg Gynecol Obstet.
1964;118:1077-1079.
6. Zancolli EA. Claw-hand caused by paralysis of the intrinsic muscles: a simple
surgical procedure for its correction. J Bone Joint Surg Am. 1957;39-
A(5):1076-1080.
7. Brown PW. Zancolli capsulorrhaphy for ulnar claw hand: appraisal of forty-
four cases. J Bone Joint Surg Am. 1970;52(5):868-877.
8. Bunnell S. Surgery of the intrinsic muscles of the hand other than those
producing opposition of the thumb. J Bone Joint Surg Am. 1942; 24(1):1-31.
9. Parkes A. Paralytic claw fingers: a graft tenodesis operation. Hand.
1973;5(3):192-199.
10. Brand P. Tendon grafting: illustrated by a new operation for intrinsic paralysis
of the fingers. J Bone Joint Surg Br. 1961;43:444-453.
11. Palande DD, Gilbie SG. The deformity of thumb in ulnar paralysis. Lepr
India. 1981;53(2):152-159.
12. Rath S. Immediate postoperative active mobilization versus immobilization
following tendon transfer for claw deformity correction in the hand. J Hand
Surg. 2008;33(2):232-240.
13. Rath S, Selles RW, Schreuders TA, et al. A randomized clinical trial
comparing immediate active motion with immobilization after tendon transfer
for claw deformity. J Hand Surg. 2009;34(3):488-494.
14. Srinivasan H. Dermadesis and flexor pulley advancement: first report on a
simple operation for correction of paralytic claw fingers in patients with
leprosy. J Hand Surg. 1985;10(6 Pt 2):979-982.
15. Ozkan T, Ozer K, Gulgonen A. Three tendon transfer methods in
reconstruction of ulnar nerve palsy. J Hand Surg. 2003;28(1):35-43.
16. Burkhalter WE. Restoration of power grip in ulnar nerve paralysis. Orthop
Clin North Am. 1974;5(2):289-303.
17. Burkhalter WE, Strait JL. Metacarpophalangeal flexor replacement for
intrinsic muscle paralysis. J Bone Joint Surg Am. 1973;55A:
1656-1676.
18. Hastings H 2nd, McCollam SM. Flexor digitorum superficialis lasso tendon
transfer in isolated ulnar nerve palsy: a functional evaluation. J Hand Surg.
1994;19(2):275-280.
19. Brandsma JW, Ottenhoff-De Jonge MW. Flexor digitorum superficialis

tendon transfer for intrinsic replacement. Long-term results and the effect on
donor fingers. J Hand Surg. 1992;17(6):625-628.
20. Reddy NR, Kolumban SL. Effects of fingers of leprosy patients having
surgical removal of sublimus tendons. Lepr India. 1981;53(4):
594-599.
SUGGESTED READINGS
Chase R. Muscle tendon kinetics. Am J Surg. 1965;109:277-282.
Omer GE. Tendon transfers for traumatic nerve injuries. J Hand Surg.
2004;4(3):214-226.
Riordan DC. Tendon transplantations in median-nerve and ulnar-nerve paralysis.
J Bone Joint Surg Am. 1953;35-A(2):312-332.

33
CHAPTER
Tendon Transfers for Radial
Nerve Injury
Rafael J. Diaz-Garcia and Kevin C. Chung
DEFINITION
■ Radial nerve palsy refers to the loss of motor control and sensation of the hand
in the distribution of the radial nerve.
■ Loss of extensor function of the wrist and digits is the greatest deficit, as the
sensation loss is of little consequence in prehension because it is on the dorsum
of the hand. Loss of wrist extension affects grip strength.
ANATOMY
■ The radial nerve is a mixed nerve composed of fibers from the C5 through T1
roots, forming as a terminal branch of the posterior cord of the brachial plexus.
■ It travels initially in the posterior compartment of the arm, where it gives off
multiple branches to the three heads of the triceps while coursing along the
spiral groove of the humerus. It passes through the intermuscular septum into
the anterior compartment, where it lies between the brachialis and
brachioradialis (BR), innervating the latter.
■ The BR, extensor carpi radialis longus (ECRL) and, at times, extensor carpi
radialis brevis (ECRB) are innervated by the proper radial nerve prior to its
entering the supinator, where it then divides into its two terminal branches.
■ The superficial branch of the radial nerve provides sensation to the radial
dorsum of the hand and fingers except for the small finger and ½ of the ring
finger.
■ The deep branch of the radial nerve innervates the supinator and becomes the
posterior interosseous nerve (PIN) as it exits, innervating ECRB, extensor
digitorum communis (EDC), extensor carpi ulnaris (ECU), abductor pollicis
longus (APL), extensor pollicis brevis (EPB), extensor pollicis longus (EPL),

and extensor indicis proprius (EIP).
■ Order of innervation is consistent, with EPL and EIP as the last two innervated
muscles. This is helpful with clinical examination at time of injury and
monitoring recovery.
PATHOGENESIS
■ The pathogenesis of radial nerve palsy is most frequently due to traumatic
injury, which can happen from injuries extending from the brachial plexus to
the forearm.
■ Idiopathic and compression causes are rarely seen.
■ Radial nerve injury is most commonly seen with humeral shaft fractures, given
its location in the spiral groove.1–3
NATURAL HISTORY
■ The mechanism of injury is an important predictor of potential recovery.
■ Open, high-energy, and penetrating injuries should be explored early, as they
have demonstrated poor recovery with nonoperative management.4
PATIENT HISTORY AND PHYSICAL FINDINGS
■ A patient with radial nerve injury will present with potential loss of elbow
extension, wrist extension, digital extension, thumb extension, and thumb
abduction.
■ The BR and ECRL are preserved in PIN palsies, as they are innervated
proximal to the elbow.
■ Tenodesis on physical exam can differentiate extensor tendon injury vs nerve
palsy.
IMAGING
■ Initial workup for acute radial nerve palsy may warrant x-rays to determine if
there are any fractures or dislocations in the extremity associated with the acute
trauma.
■ Nerve conduction studies and electromyography may be helpful in the workup
of radial nerve palsy, helping to determine the level of the lesion. Axonal loss
is evident 3 weeks after injury.
■ MRI of the brachial plexus may be warranted if there is concern for a lesion at
this level.
DIFFERENTIAL DIAGNOSIS

■ Extensor tendon laceration/rupture
■ Isolated radial nerve injury
■ Cervical radiculopathy
■ Volar subluxation of the MCP joint (in inflammatory arthritis)
■ Brachial plexus lesion
NONOPERATIVE MANAGEMENT
■ Hand therapy is essential to educate the patient in a home exercise program to
maintain motion and prevent contracture while waiting for nerve recovery.5
■ Patients should be given a wrist splint for support to counteract the unopposed
wrist flexors. Hand intrinsic muscles can provide some digital extension.
SURGICAL MANAGEMENT
■ The goals of reconstruction depend on the level of injury of the radial nerve.
■ Injuries in the arm require reconstruction of independent wrist extension,
finger extension, and thumb extension.
■ Injuries in the forearm of the PIN will spare the ECRL and sometimes the
ECRB, which preserve wrist extension.
■ Donor muscles include the pronator teres (PT), flexor carpi ulnaris (FCU),
flexor carpi radialis (FCR), flexor digitorum superficialis (FDS), and palmaris
longus (PL). The different reconstructions are usually referred to by which
transfer is used for reconstruction of digital extension.
■ Tendon transfers should be delayed until after potential nerve recovery is
completed. However, unlike median or ulnar nerve transfers, sometimes radial
nerve transfers are done at the time of nerve repair/reconstruction to minimize
need for bracing.
Preoperative Planning
■ Clinical exam of the patient helps the surgeon decide what functions must be
recreated and what donor muscles are available for each function.
■ Hand and wrist joints should be as supple as possible.
■ Wrist motion, particularly flexion, is an important characteristic for radial
nerve transfers. That is because additional excursion is obtained with wrist
flexion to help the FCR or FCU to fully extend the fingers.
■ If there is significant wrist stiffness, one should consider FDS to EDC
transfers for better excursion of the transfer.

Positioning
■ The patient is placed in the supine position with a tourniquet on the upper arm.
■ The OR lights are positioned with one projecting from proximally and one
distally from the operative site.
Approach
■ Like with all tendon transfers, one should plan for the tendons to glide through
a smooth and scar-free wound bed and each transfer should serve one function.
■ If there is scarred tissue along the path of the transfer, it must be replaced by
soft supple tissue either through serial scar excision or a flap procedure.
T E C H N I Q U E S
■ Reconstruction of Wrist Extension: Pronator Teres
to Extensor Carpi Radialis Brevis
■ A radial-sided longitudinal incision is planned over the midpoint of the
forearm to expose both the PT and the second extensor compartment (TECH
FIG 1A,B).
■ The pronator teres (PT) is identified inserting on the radial shaft, deep to the
brachioradialis (BR) and radial artery.
■ Additional length is acquired by harvesting a strip of distal periosteum
along with the distal tendon.
■ The proximal PT is freed of its attachments to the other volar muscles to
improve the excursion.
■ The extensor carpi radialis brevis (ECRB) is localized just distal to the
musculotendinous junction. A smooth path is created over the BR and the
superficial radial nerve.
■ The PT is passed over the BR to the ECRB. The ECRL can also be
incorporated into the tendon transfer, but this is typically not done.
■ If the ECRL and ECRB has no chance of recovery, the tendon transfer is
done in the end-to-end fashion, rather than end-to-side to provide maximum
excursion. Tension is set.
■ A Pulvertaft tendon weave is done using 2-0 braided nonabsorbable sutures.
■ The wrist tendons are reconstructed first to facilitate setting tension for the

fingers and thumb.
■ The wrist should be at a neutral posture after the tendon transfer is secured.
■ Each end of the tendon is grasped with a clamp to set the tension, and if the
tension is too loose, horizontal mattress sutures are used to “fine-tune” and
tighten the transfer (TECH FIG 1C–E).
TECH FIG 1 • A,B. The PT is identified where it inserts
on the radial shaft, deep to the brachioradialis. C,D.
The PT is woven through ECRL and ECRB tendons
just distal to the musculotendinous junction. E,F. Path
of the transfer.

■ Reconstruction of Finger Extension
Flexor Carpi Radialis to Extensor Digitorum Communis6,7
■ A longitudinal volar incision is used to expose the flexor carpi radialis (FCR)
and palmaris longus in the distal forearm.
■ The distal tendon is transected at the distal wrist crease.
■ There are two paths of transfer of the FCR.
■ A subcutaneous tunnel in a radial direction to the dorsum of the wrist. This
is our preferred transfer, as the path is created for the EPL as well.
■ A tunnel through the interosseous membrane (IOM) to the dorsum of the
wrist. This has a more direct line of pull but has a higher incidence of
postoperative adhesions.
■ Point of insertion on each tendon is chosen to recreate the normal digital
cascade by detaching each finger tendon and suture it along the path of the
FCR.
■ Pulvertaft weaves are held in place with nonabsorbable sutures (TECH FIG
2A–C).
■ Final tension is set to achieve the tenodesis posture: 30-degree wrist
extension is accompanied by 90 degrees of finger flexion; 30 degrees of wrist
flexion is accompanied by full finger extension (TECH FIG 2D,E).
Flexor Carpi Ulnaris to Extensor Digitorum Communis8–10
■ A longitudinal incision is made over the distal aspect of the flexor carpi
ulnaris (FCU) tendon at the pisiform.
■ The ulnar neurovascular bundle must be identified and protected.
■ The FCU is freed from its surrounding attachments to achieve sufficient
excursion.
■ A broad subcutaneous tunnel is created in an ulnar direction toward the
dorsum of the wrist.
■ A dorsal incision is made to expose the extensor digitorum communis (EDC)
and release the proximal extensor retinaculum.
■ Pulvertaft weaves are held in place with nonabsorbable sutures (TECH FIG
3).
■ Point of insertion and tensioning is done similarly to the FCR transfer.

TECH FIG 2 • A. The FCR to EDC is completed via a
subcutaneous tunnel along the radial side of the wrist.
B,C. Relationship between the FCR donor and the
EDC tendons. The transfer can be either
subcutaneous or transinterosseous membrane. D. Full
digital extension is seen with slight wrist flexion. E.
Full digital flexion is possible with wrist extension.
TECH FIG 3 • The FCU to EDC is completed via a

subcutaneous tunnel along the ulnar side of the wrist.
Care is kept to ensure there is no injury or
compression to the dorsal ulnar sensory branch. The
distal FCU muscle can be debrided if it makes the
weave too bulky.
Flexor Digitorum Superficialis (FDS-IV) to Extensor Digitorum
Communis11
■ FDS to EDC transfer is best suited for patients with poor wrist motion
preoperatively.
■ The better excursion of the FDS (70 mm) results in better digital extension.
■ In most patients, wrist motion from tenodesis compensates for the limited
excursion of the wrist flexors.
■ The FDS tendon is released from the ring finger just proximal to the carpal
tunnel via a volar wrist incision.
■ Alternatively, it can be released at the PIP joint through a Bruner-style
incision if greater tendon length is needed in the case of tendon rupture or
loss.
■ For radial nerve palsy, when the extensor tendons are intact, the FDS is
transected at the wrist and will be transferred dorsally to attach to the
extensor tendons proximal to the extensor retinaculum.
■ It is retrieved from the volar forearm incision used to harvest the other
tendons.
■ The FDS to the long finger is transferred to the index and thumb extensor
tendons, coordinating both these digits for precise pinch (TECH FIG 4A–C).
■ The IOM is exposed proximal to the pronator quadratus.
■ Making sure to not disrupt the central band of the IOM, an opening is made
to allow for the tendons to pass from volar to dorsal (TECH FIG 4D).
■ Dorsally, the FDS-IV is transferred to the EDC long through small fingers
with a Pulvertaft weave.
■ This transfer is grouped in this fashion to coordinate the ulnar digits in
power grip.
■ Tension is set with the wrist at 30 degrees of extension and the MP joints at
full extension (TECH FIG 4E).

TECH FIG 4 • A,B. Dorsal and volar incisions,
respectively, are designed for exposure of tendons. C.
The FDS to the long and ring fingers are divided just
proximal to the carpal tunnel. D. The tendons are
passed from volar to dorsal via the interosseous
membrane. E. The FDS-IV is woven into the EDC
tendons (yellow arrow), and the FDS-III is woven into
the EPL and EIP (black arrow).
■ Reconstruction of Thumb Extension: Palmaris
Longus to Extensor Pollicis Longus
■ Palmaris longus (PL) is identified through the volar incision used to expose
FCR. It is freed from its surrounding attachments to maximize excursion.
■ A subcutaneous tunnel toward the thumb is created below the radial artery

and cutaneous nerves along the radial aspect of the wrist (TECH FIG 5A).
■ If nerve recovery is not expected, the extensor pollicis longus (EPL) tendon
is released proximally through the dorsal incision.
■ If nerve recovery is expected and transfer is being used as a temporizing
measure, the EPL is kept in continuity but released from the third
compartment to improve the vector of pull of the transfer.
■ A Pulvertaft weave is done between the PL and EPL tendons.
■ Tension is set with the thumb fully extended with the wrist in neutral.
■ Transfer is secured with nonabsorbable suture (TECH FIG 5B–D).
TECH FIG 5 • A. FCR and PL can both be harvested
from the same radial incision. B. FCR is woven to
EDC and PL is woven to EPL. C,D. Transfer of PL to
EPL.
PEARLS AND PITFALLS
Preoperative
evaluation
■ Critically assess donor muscle availability and strength.
■ Determine patient goals and potential for additional nerve recovery.
Tendon transfers for wrist extension and thumb extension may be

done even with expected recovery.
■ Because wrist flexors do not match excursion of finger extensors,
preoperative assessment can help determine working range of
transfer and how to set tension.12
Finger
extension
transfer
■ Choice between FCR and FCU for digital extension is not
straightforward. Neither matches excursion, though FCU has greater
force. However, loss of FCU may result in loss of “dart thrower’s
motion.”
■ Interosseous membrane passage must allow for easy tendon gliding.
Prone to greater adhesions.
POSTOPERATIVE CARE
■ The patient is usually splinted with the wrist in 30 to 40 degrees of extension
and the MP joints in full extension. The interphalangeal joints can undergo
passive range of motion, as the intrinsic hand muscles drive their extension.
■ At the first postoperative visit, an Orthoplast splint is fabricated to wrist and
MP extension. At 3 weeks, gentle active range of motion of the wrist is
commenced several times a day. Integration of digital extension is added as
wrist motion improves. Passive range of motion is started at 6 weeks.
Strengthening is started at 8 weeks.
■ A knowledgeable hand therapist plays an important role in the surgical
outcomes.
OUTCOMES
■ Most radial nerve palsy patients can perform normal activities of daily living
with their hand after complete recovery from surgery.
■ With restoration of wrist extension, grip strength is 40% to 50% of the
contralateral side and digital extension is 34% to 75% of normal.12–14
COMPLICATIONS
■ Suboptimal results may be a result of choosing a weak motor for transfer or
incorrect vector of pull.
■ Radial deviation can result from use of FCR. PIP joint hyperextension or
flexion contractures can result from use of FDS tendons.
■ Tendon adhesions can result from prolonged immobilization, but tenolysis
should not be considered until at least 9 months out from surgery.
■ Tendon ruptures can be prevented with patient education and progressive

therapy advancement. Transfer attenuation may require revision.
REFERENCES
1. Amillo S, Barrios RH, Martinez-Peric R, Losada JI. Surgical treatment of the
radial nerve lesions associated with fractures of the humerus. J Orthop
Trauma. 1993;7(3):211-215.
2. Thomsen NO, Dahlin LB. Injury to the radial nerve caused by fracture of the
humeral shaft: timing and neurobiological aspects related to treatment and
diagnosis. Scand J Plast Reconstr Surg Hand Surg. 2007;41(4):153-157.
3. Burkhalter WE. Early tendon transfer in upper extremity peripheral nerve
injury. Clin Orthop Relat Res. 1974(104):68-79.
4. Ring D, Chin K, Jupiter JB. Radial nerve palsy associated with high-energy
humeral shaft fractures. J Hand Surg [Am]. 2004;29(1):144-147.
5. Walczyk S, Pieniazek M, Pelczar-Pieniazek M, Tabasz M. Appropriateness
and effectiveness of physiotherapeutic treatment procedure after tendon
transfer in patients with irreversible radial nerve injury. Ortop Traumatol
Rehabil. 2005;7(2):187-197.
6. Brand PW. Biomechanics of tendon transfer. Orthop Clin North Am.
1974;5(2):205-230.
7. Ishida O, Ikuta Y. Analysis of Tsuge’s procedure for the treatment of radial
nerve paralysis. Hand Surg. 2003;8(1):17-20.
8. Riordan DC. Radial nerve paralysis. Orthop Clin North Am. 1974;5(2):
283-287.
9. Riordan DC. Tendon transfers in hand surgery. J Hand Surg [Am]. 1983; 8(5
Pt 2):748-753.
10. Raskin KB, Wilgis EF. Flexor carpi ulnaris transfer for radial nerve palsy:
functional testing of long-term results. J Hand Surg [Am]. 1995;20(5):737-
742.
11. Chuinard RG, Boyes JH, Stark HH, Ashworth CR. Tendon transfers for radial
nerve palsy: use of superficialis tendons for digital extension. J Hand Surg
[Am]. 1978;3(6):560-570.
12. Lieber RL, Ponten E, Burkholder TJ, Friden J. Sarcomere length changes
after flexor carpi ulnaris to extensor digitorum communis tendon transfer. J
Hand Surg [Am]. 1996;21(4):612-618.
13. Al-Qattan MM. Tendon transfer for radial nerve palsy: a single tendon to
restore finger extension as well as thumb extension/radial abduction. J Hand
Surg Eur Vol. 2012;37(9):855-862.

14. Altintas AA, Altintas MA, Gazyakan E, et al. Long-term results and the
Disabilities of the Arm, Shoulder, and Hand score analysis after modified
Brooks and D’Aubigne tendon transfer for radial nerve palsy. J Hand Surg
[Am]. 2009;34(3):474-478.

34
CHAPTER
Tendon Transfers for
Combined Median and
Ulnar Nerve Injury
Kate Elzinga and Kevin C. Chung
DEFINITION
■ Combined median and ulnar nerve injuries cause major impairment of the
upper extremity. The ability to perform fine pinch and power grasp is lost. The
volar and dorsoulnar hand is insensate. The balance between the flexor and
extensor muscle groups of the upper extremity is absent. Prehensile function is
greatly reduced.
■ Low median and ulnar nerve injuries are the most common combined nerve
injury of the upper extremity. Nerve lacerations should be repaired acutely. In
the case of a delayed nerve injury presentation or incomplete recovery
following nerve repair, tendon transfers can be used to augment function.
■ Tendon transfers can be combined with nerve transfers and free muscle
transfers to help maximize the function of the injured upper limb. However, in
combined nerve injuries, the number of nerves available for transfer is also
limited.
■ For a successful tendon transfer, a redundant tendon is harvested for transfer,
minimizing donor-site morbidity while restoring a lost function. Finding an
appropriate donor tendon is more difficult in combined nerve injuries
compared to isolated nerve injuries; a greater number of tendons are affected,
which results in multiple functional deficits while fewer intact tendons remain
for transfer.
■ Sensory deficits are also greater in combined nerve injuries (FIG 1).
Reconstructive outcomes are inferior in combined nerve injuries compared to
single nerve injury injuries.
■ Donor-site morbidity must be carefully considered prior to tendon harvest for

transfer in combined nerve injuries. These patients have a limited number of
tendons available for transfer. The patient’s individualized goals must be
carefully considered. A personalized reconstructive plan is created to best
restore the patient’s function.
■ The patient’s physical exam is central in formulating the operative plan.
Missing functions, as well as available donor tendons, are documented. Once
the functional deficits and available donors have been determined, the donors
are matched to the deficits for reconstruction.
■ Following the principles of tendon transfers optimizes patient outcomes:
■ Expendable donor
■ Straight line of pull
■ One muscle for one function
■ Similar force of contraction
■ Adequate excursion
■ Synergism
■ Skeletal stability
■ Stable, supple soft tissue bed
■ Full passive range of motion (ROM)
■ Synergistic transfers are the most intuitive for patients to learn and offer the
quickest return of function. Wrist extension is synergistic with finger flexion,
whereas wrist flexion is linked with finger extension.
■ Compared to single nerve injuries, following a combined nerve injury,
achieving synergy can be more difficult.
■ Ideally, tendon excursion of the donor tendon should match that of the
recipient tendon to best restore the biomechanics of the upper extremity. The
wrist flexors and extensors have 3.3 cm of excursion, the finger extensors have
5 cm of excursion, and the finger flexors have 7 cm of excursion.1
■ Staging of procedures is important. Only tendon transfers that can be
rehabilitated with hand therapy together should be performed at the same time.
Multiple surgeries may be required.
ANATOMY
■ Proximally, the median nerve innervates the pronator teres, flexor carpi
radialis (FCR), palmaris longus (PL), and flexor digitorum superficialis (FDS).
■ The anterior interosseous nerve (AIN) originates from the median nerve 6 to 8
cm distal to the medial epicondyle. It innervates the flexor digitorum profundus
(FDP) to the index and middle fingers, flexor pollicis longus (FPL), and

pronator quadratus.
■ The median nerve continues distally to provide motor innervation to the
lumbricals to the index and middle fingers and the thenar muscles (abductor
pollicis brevis [APB], flexor pollicis brevis [FPB], and opponens pollicis) and
sensory innervation to the thumb, index, middle, and radial half of the ring
finger.
■ A low median nerve injury, distal to the origin of the AIN, causes the loss of
thumb opposition and sensory deficits in the volar-radial hand.
■ A high median nerve injury affects all of the muscles listed above. In
addition to thumb opposition and sensory deficits, forearm pronation is lost,
wrist flexion is weakened, flexion of all four proximal interphalangeal (PIP)
joints as well as the index and middle finger distal interphalangeal (DIP)
joints is lost, and thumb flexion is lost.
■ The ulnar nerve innervates, from proximal to distal, the flexor carpi ulnaris
(FCU), FDP to the ring and small fingers, hypothenar muscles (abductor digit
minimi [ADM], opponens digiti minimi, flexor digiti minimi), lumbricals of
the ring and small fingers, dorsal and palmar interossei, deep head of the FPB,
and adductor pollicis (AdP). The ulnar nerve provides sensory innervation to
the ulnar ring and bilateral small fingers.
FIG 1 • Following a combined median and ulnar nerve
injury, sensory deficits are profound in the hand. All
volar hand sensation is lost. Dorsal sensation over the
index and middle fingers distal to the PIP joints and

over the entire ring and small fingers is also absent.
Yellow, median nerve; blue, ulnar nerve; pink, radial
nerve.
■ A low ulnar nerve injury denervates the intrinsic muscles (hypothenar
muscles, lumbricals ring and small fingers, interossei, deep head of FPB,
AdP) of the hand.
■ A high ulnar nerve injury occurs more proximally and denervates the
extrinsic muscles (FCU, FDP ring and small fingers) of the hand in addition
to the intrinsic muscles.
■ Connections are common between the ulnar and median nerves, occurring in
9% to 27% of forearms1,2 and 83% of hands.3 However, connections between
the radial nerve to either the median or the ulnar nerve have not been reported.
In combined median and ulnar nerve injuries, motor and sensory deficits are
profound and complete.
■ A combined low median and ulnar nerve injury leads to the loss of thumb
opposition and hand intrinsic function (thenar and hypothenar muscles,
lumbricals, interossei). Forearm pronation, wrist flexion, and finger flexion
are preserved. Hand sensation remains intact in the distribution of the
superficial branch of the radial nerve over the dorsoradial hand only.
■ In addition to the deficits of a low combined palsy, a combined high median
and ulnar nerve injury results in the loss of forearm pronation, wrist flexion,
finger flexion, and thumb flexion.
■ The radial nerve innervates, from proximal to distal, the triceps,
brachioradialis (BR), extensor carpi radialis longus (ECRL), extensor carpi
radialis brevis (ECRB), supinator, extensor carpi ulnaris (ECU), extensor
digitorum communis (EDC), extensor digit minimi (EDM), abductor pollicis
longus (APL), extensor pollicis longus (EPL), extensor pollicis brevis (EPB),
and the extensor indicis proprius (EIP).
■ Expendable radial nerve-innervated tendons for wrist and hand reconstruction
include:
■ The BR can be transferred if the biceps and/or brachialis are intact to
maintain elbow flexion. The biceps and brachialis muscles are innervated by
the musculocutaneous nerve and are not affected by median and ulnar nerve
injuries.
■ Two of three of the ECRL, ECRB, and ECU can be harvested. One of these

tendons must be preserved to maintain wrist extension.
■ The EIP and EDM can be transferred if the EDC is intact to maintain
extension of the index and small fingers.
■ The EPB can be harvested if the EPL is intact to provide thumb extension.
■ The APL has multiple slips. As long as one slip of the APL is preserved for
thumb abduction, the additional slips can be harvested for transfer.
PATHOGENESIS
■ Lacerations to the volar wrist are the most common cause of combined low
median and ulnar nerve injuries. The median and ulnar nerves are at increased
risk in the distal volar forearm because of their superficial location here
compared to their location deep to the muscles in the proximal forearm and
arm.
■ More proximal injuries, typically resulting from sharp mechanisms, can result
in high combined nerve injuries.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Selection of appropriate donor tendons for transfer is critical to restore
function while minimizing donor-site morbidity.
■ A comprehensive history and physical examination is performed to determine
the patient’s functional deficits and their reconstructive goals.
FIG 2 • This patient had a low combined median and
ulnar nerve injury of the right hand. A claw hand
deformity is viewed from dorsal (A) and lateral (B). The
finger MCP joints are extended, and the IP joints are
flexed.

■ The patient’s age, handedness, occupation, and avocations are documented.
■ Limitations in activities of daily living, recreation, and work are discussed.
■ The patient’s goals are explored, including their plans for return to work,
their availability and willingness to undergo secondary procedures and hand
therapy, and the importance of appearance.
■ Discussion with the patient’s hand therapist provides further insight into the
patient’s deficits and can help prioritize reconstructive goals. Reconstruction is
focused on providing the most functional benefit to each individual patient.
■ The patient’s compliance with therapy and their anticipated ability to retrain
transferred tendons is assessed by the therapist and considered when
determining the reconstructive plan.
■ Important considerations from the patient’s past medical history include
smoking, diabetes mellitus, peripheral vascular disease, connective tissue
disorders, arthritis, Dupuytren disease, and previous hand injuries.
■ On physical examination, a claw hand deformity is more apparent in a low
median and ulnar nerve palsy than in a high injury (FIG 2).
■ In low injuries, FDS and FDP innervation remain intact causing unopposed
flexion of the interphalangeal (IP) joints of the fingers due to the denervation
of the interossei and lumbricals. The loss of the intrinsic muscles of the hand
also leads to a hyperextension deformity of the metacarpophalangeal (MCP)
joints due to unopposed extension through the extrinsic finger extensors.
■ The Bouvier test is used to assess if the extensor mechanism is functioning
normally. The patient’s MCP hyperextension is blocked and then he or she is
asked to extend their PIP joints (FIG 3).
■ If the MCP flexion facilitates the patient’s active PIP joint extension, the test
is positive and the claw is defined as “simple,” because by procedures to keep
the MCP joints flexed, the PIP joints can extend via the extrinsic extensor
tendons. However, the word “simple” is a misnomer because other than fusion
of the MCP joints in flexion, all the soft tissue procedures applied to flex the
MCP joints will stretch out over time.
■ If the patient cannot extend their PIP joints, the test is negative and the claw
is “complex.” Etiologies of a complex claw include central slip attenuation,
central slip adherence to the PIP joint, and volar subluxation of the lateral
bands.
IMAGING
■ If the patient’s clinical history is suspicious for arthritis, plain radiographs are

taken of the hand and wrist to assess the joints. Painful arthritic MCP and IP
joints are better reconstructed with arthrodesis than with soft tissues procedures
such as tendon transfers. Wrist arthrodesis is typically avoided to maintain
wrist tenodesis.
FIG 3 • The Bouvier test is used to assess the extensor
tendon mechanism in claw hand deformities. A. The
examiner holds the MCP joints in flexion to passively
correct the MCP hyperextension deformity. B. The
patient is then asked to extend the PIP joints. If the
patient is able to extend, the extensor mechanism is
functioning properly and the claw is designated
“simple,” as shown here. If the patient cannot extend
the PIP joints, the claw is designated “complex.”

FIG 4 • Thermoplastic splints can be used to correct a
claw hand deformity and unopposed thumb extension in
combined median and ulnar nerve injuries. Here, the
anticlaw splint corrects the patient’s simple claw;
correcting her MCP hyperextension permits active
extension of her IP joints. The dorsal blocking thumb
splint prevents the hyperextension deformity of the
thumb at the carpometacarpal, MCP, and IP joints.
■ Electrodiagnostic studies can be used to assess recovery following incomplete
nerve injuries and after nerve repair to aid in planning for tendon transfers.
■ Donor muscles can be tested if there is concern of their integrity. Donor
muscles lose one medical research council grade of strength when transferred;
grade 5 muscles are normal strength and are preferred as donors.
NONOPERATIVE MANAGEMENT
■ Hand therapy is essential to maintain supple joints prior to reconstruction. A
tendon transfer will not restore active ROM if the joint is stiff and incomplete
passive ROM is present.
■ Passive ROM should be optimized prior to surgery.
■ If necessary, joint contracture release is performed prior to tendon transfer.
■ Patients can be taught how to use wrist tenodesis to improve their hand
function.
■ Wrist flexion and extension can increase the amplitude of finger extension

and flexion by 2.5 cm, respectively.1
■ Preoperative splinting can be used correct a patient’s thumb and finger MCP
joint hyperextension following a combined median and ulnar nerve injury (FIG
4).
■ If the patient finds the splints helpful, surgical intervention—including thumb
MCP arthrodesis and index, middle, ring, and small finger MCP volar
capsulodesis or arthrodesis—is indicated.
SURGICAL MANAGEMENT
■ Tension of the tendon transfer is critical for restoration of function while
preventing the loss of ROM of other joints. In general, when suturing the
tendon transfer, the joints as positioned as though the donor muscle is
contracting and the transferred tendon is secured under tension.
■ To minimize rupture rates, tendon transfers are best secured using three
Pulvertaft weaves.4 The donor tendon is divided distally and the recipient
tendon is divided proximally to facilitate adequate tendon weaving.
■ The tendon transfer tension is set with one Pulvertaft weave and then wrist
tenodesis is checked to ensure adequate passive ROM. Adjustments in tension
can be made with the second and third Pulvertaft weaves.
■ Tendon transfers can be performed in an end-to-end or end-to-side fashion.
■ End-to-end suturing facilitates a direct line of pull and is used if the recipient
tendon is not expected to have any spontaneous recovery, for example, after
complete denervation from an unrepaired nerve transection.
■ If the nerve has been repaired and some muscle recovery is expected, the
tendon transfer is performed in an end-to-side fashion to augment existing
function.
■ A direct line of pull maximizes the power of the tendon transfer. If a direction
change is unavoidable, the tendon should be passed around a fixed structure
that behaves as a pulley, for example, the EIP tendon around the distal ulna to
abduct the thumb.
Preoperative Planning
■ When selecting a tendon for transfer, any resulting weakness must be
considered. One tendon must remain intact to perform the donor’s original
function.
■ Tendon gliding occurs best in a supple, stable soft tissue bed. If needed, scar
contracture releases and flap reconstruction are performed prior to tendon

transfers to permit optimal tendon gliding and to minimize tendon adhesions.
■ A stable platform with adequate bone and joint stability is required prior to
tendon transfer. If required, arthrodesis of select joints is performed prior to
tendon transfer.
■ A thumb MCP arthrodesis can be helpful to correct severe thumb
hyperextension following the loss of thumb flexion in a median nerve palsy.
The MCP is fused in 15 to 20 degrees of flexion and 15 degrees of pronation
using headless compression screws, a dorsal plate, or tension band wiring.
■ Wrist fusion permits all three wrist extensors (ECRL, ECRB, ECU) to be
harvested for transfer; however, this is not typically recommended because it
will eliminate wrist tenodesis, which augments the excursion of the remaining
tendons.
Positioning
■ The patient is positioned supine with the arm extended on a hand table.
■ A tourniquet is placed on the upper arm.
Approach
■ Loupe magnification is helpful. Incisions are planned prior to inflation of the
tourniquet.
■ We prefer to use 3-0 polyester suture for our tendon transfers. Two sutures are
placed to secure each Pulvertaft weave.
T E C H N I Q U E S
■ Low Combined Median and Ulnar Nerve Palsy
Thumb Opposition
■ In a low combined median and ulnar nerve injury, the ADM is denervated,
but the FDS, PL, and EIP maintain their innervation and can be used as donor
tendons for an opponensplasty. Only the EIP is available in high combined
median and ulnar nerve palsies.
■ The EIP is our preferred tendon transfer. It has minimal donor-site morbidity
and has sufficient length to reach the APB insertion without a tendon graft.
■ If the EIP is being used to restore another function of the hand following a

low median nerve injury, the ring finger FDS is our second choice for an
opponensplasty.
■ The ADM is only transferred in cases of congenital hypoplastic thumb or in
combined median and radial nerve injuries.
■ The PL is primarily used as an adjunct in elderly patients with severe carpal
tunnel syndrome and thenar wasting. This tendon transfer provides more
thumb abduction than true opposition.
Low Injury: Ring Finger FDS to APB Tendon Transfer
■ The FDS is harvested and retrieved via transverse incisions first at the base
of the proximal phalanx and then proximal to the carpal tunnel.
■ A pulley is created by passing the FDS through a window in the transverse
carpal ligament to reroute it obliquely across the palm.
■ The FDS is secured to the APB at its insertion on the radial base of the
proximal phalanx of the thumb.
Low or High Injury: EIP to APB Tendon Transfer
■ The EIP is divided distally over the dorsal index finger MCP joint using a
transverse or a V-shaped incision (TECH FIG 1A).

TECH FIG 1 • A. Two incisions are used over the
dorsal hand and wrist for EIP harvest. The EIP is first
identified over the index finger MCP joint using a
transverse or a V-shaped incision. Next, it is identified
over the dorsal wrist through a longitudinal incision
distal to the extensor retinaculum. B. The EIP (black
arrows) is divided for transfer over the index finger
MCP joint. It is located ulnar to the EDC tendon (red
arrow) in most patients. Next, it is retrieved over the
dorsal wrist. C. The EIP is rerouted around the ulnar
wrist, proximal to the pisiform, and then tunneled

subcutaneously to the APB insertion on the radial
base of the proximal phalanx of the thumb. D. The EIP
is secured to the APB tendon at its insertion using
three Pulvertaft weaves secured with 3-0 polyester
suture. E,F. The position of the right thumb is
improved following opponensplasty, shown here at the
end of the surgery (E) and at the 2-month follow-up
visit (F).
■ The EIP is located ulnar to the EDC in most patients (TECH FIG 1B);
anatomic variations of the EIP and EDC over the MCP joint exist in 19% of
patients.5
■ The distal stump of the EIP can be sutured end to side to the index finger
EDC tendon to prevent an extensor lag of the index finger.
■ The EIP is retrieved over the distal wrist, using a longitudinal incision distal
to the extensor retinaculum (TECH FIG 1B)
■ It is then rerouted around the ulnar side of the hand, superficial to the FCU,
using an incision proximal to the pisiform (TECH FIG 1C).
■ After placement through the pulley, the EIP is tunneled through the
subcutaneous tissue of the palm, volar to the neurovascular structures, to the
APB tendon on the radial base of the proximal phalanx of the thumb.
■ The EIP is sutured into the APB with the wrist in neutral and the thumb
maximally palmarly abducted (TECH FIG 1D–F).
■ Setting tension is unnecessary because the EIP will barely reach the APB;
wrist flexion may be required to suture the tendon in place.
■ After the tendon juncture has healed, the wrist is slowly brought to neutral
position.
Thumb Adduction: ECRB to AdP With Tendon Graft
■ Thumb adduction and pinch can be restored by transferring a tendon to the
adductor pollicis (AdP) near its insertion on the ulnar base of the proximal
phalanx of the thumb.
■ The FDS from the ring finger or the ECRB are commonly transferred; the
ECRB must be extended using a tendon graft to reach the AdP.
Low Injury: FDS to AdP Tendon Transfer

■ In low median and ulnar nerve injuries, the FDS to the ring finger can be
transferred to the AdP. The FDP to the ring finger is intact in these injuries
and maintains finger flexion.
■ The FDS is divided distal to the A1 pulley using an incision over the volar
base of the ring finger proximal phalanx.
■ The FDS is then retrieved through a second incision ulnar to the thenar
crease at the base of the palm and is passed to the AdP insertion
subcutaneously and sutured to the AdP through a third incision over the ulnar
base of the thumb proximal phalanx.
■ Tension is set with the wrist in neutral, the thumb adducted against the index
finger, and the FDS at its resting length (TECH FIG 2).6
Low or High Injury: ECRB to AdP Tendon Transfer
■ The ECRB is divided at its insertion over the dorsal base of the middle
finger metacarpal.
■ Using a second incision proximal to the extensor retinaculum, the ECRB is
retrieved proximally.
■ A third incision is used to expose the AdP over the ulnar base of the
proximal phalanx of the thumb.
■ A tendon graft is secured to the AdP and then passed through the
intermetacarpal space between the index and middle finger metacarpals from
the volar to the dorsal hand using a fourth incision longitudinally over the
proximal third of the second intermetacarpal space.
■ This graft is passed deep to the flexor tendons and superficial to the AdP.
■ The tendon graft is secured to the distal ECRB over the dorsal wrist with the
wrist in neutral and the thumb adducted against the index finger (TECH FIG
3).

TECH FIG 2 • The ring finger FDS tendon is harvested
at the base of the finger (A) and then rerouted for
transfer to the adductor pollicis tendon on the ulnar
proximal phalanx of the thumb (B) to restore thumb
adduction following an ulnar nerve injury.
Index Finger Abduction: APL to First Dorsal Interosseous With
Tendon Graft
■ In 84% of people, the APL tendon has multiple tendinous slips7; up to 14
slips have been recorded.8 An accessory slip of APL can be harvested as a
donor tendon in patients with multiple slips. In the 16% of patients with a
single APL tendon, half of the APL tendon can be harvested longitudinally
for transfer.
■ A slip of the APL can be transferred to the first dorsal interosseous (DIO)
tendon near its insertion on the radial index finger metacarpal to restore index
finger abduction for pinch.
■ A tendon graft is required for the APL to reach the first DIO tendon (TECH
FIG 4).
■ The palmaris longus, plantaris, extensor digitorum longus (to the second,
third, or fourth toes), or flexor digitorum longus (to the second, third,
fourth, or fifth toes) can be used as a tendon graft.

TECH FIG 3 • Thumb adduction can be restored by
transferring the ECRB to the adductor pollicis near its
insertion on the ulnar base of the proximal phalanx of
the thumb (red arrow), using a tendon graft. The graft
first secured distally, passed through the second
intermetacarpal space (black arrow), and then
secured to the ECRB tendon proximally.
TECH FIG 4 • To restore index finger abduction and

pinch, a slip of the APL is transferred to the first DIO.
A tendon graft is necessary for the APL to reach the
insertion of the first DIO on the radial base of the
index finger proximal phalanx.
■ A slip of APL is harvested from its insertion on the radial aspect of the
thumb metacarpal base using a longitudinal or V-shaped incision.
■ A midlateral incision is made over the radial base of the index finger
proximal phalanx to identify the first DIO.
■ The tendon graft is secured to the first DIO and then passed proximally over
the dorsal hand in the subcutaneous tissues to the proximal incision, where it
is secured to the APL tendon.
Finger Clawing: FDS (Low Injury) or ECRL (High Injury)
Tendon Transfer to the Lateral Bands of the Index, Middle,
Ring, and Small Fingers
■ For a simple claw, MCP joint hyperextension can be treated via static
procedures such as volar MCP capsulodesis (the volar plate is detached and
advanced proximally and secured with a bone anchor to the volar metacarpal
to maintain the MCP in 45 degrees of flexion) (TECH FIG 5) or the Zancolli
lasso (the FDS is divided over the distal proximal phalanx, removed from
under the A2 pulley, turned proximally volar to the A1 pulley, and sutured to
itself over the MCP joint).

TECH FIG 5 • A. This patient had a simple claw
identified using the Bouvier test. MCP volar
capsulodesis was performed for the index, middle,
ring, and small fingers to correct the MCP
hyperextension deformity. A volar incision was made
over the volar MCP heads. The excess skin was
marked for resection here. B. The index finger volar
plate is shown here, with its proximal extent outlined
with a purple marker. C. The proximal volar plate was
elevated and then advanced proximally and secured
to the metacarpal using a bone anchor to maintain the
MCP in 45 degrees of flexion to correct the MCP claw
hyperextension deformity. D. One bone anchor was

used to secure each proximal volar plate proximally to
the volar metacarpal. The four bone anchors were
placed (E), and then each volar plate was advanced
proximally and secured using the bone anchor suture
to hold the MCP joints in 45 degrees of flexion (F).
■ Restoration of MCP joint flexion in a simple claw permits the patient to
extend their IP joints through their extrinsic extensors (EDC, EIP, EDM). The
main drawback of these soft tissues procedures is their tendency to stretch out
over time.
■ Our recommended long-term solution is to fuse the MCPJ in flexion (TECH
FIG 6) or to perform a dynamic tendon transfer.
■ In a complex claw, both MCP joint flexion and IP joint extension
reconstruction are required. A dynamic tendon transfer is used. A four-tailed
middle finger FDS (low injury) or ECRL (low or high injury) is commonly
used as donor tendon for transfer in complex, and simple, claw hands.
■ If used, the ECRL must be extended with a tendon graft to enable it to
reach the clawed digits.
■ Tendon transfers in a simple claw are inserted into the A2 pulley to restore
MCP joint flexion only.
■ In a complex claw, the insertion is into the lateral bands over the proximal
phalanx to restore both MCP joint flexion and IP joint extension.
■ The tendon is passed from the distal palm, volar to the deep transverse
metacarpal ligament, to the lateral bands of the affected digits.
■ The tendon is secured to the ulnar lateral band for the index finger and to the
radial lateral band for the middle, ring, and small finger.

TECH FIG 6 • A. To correct this patient’s simple claw
deformity of his index, middle, ring, and small fingers
following a combined high median and ulnar nerve
injury, MCP joint fusions were performed. The MCP
joints could be passively flexed, but not actively. B.
Dorsal incisions were used over the MCP joints. Two
K-wires were used to fuse each of the patient’s MCP
joints in 45 degrees of flexion, as shown here on the
PA radiograph (C), lateral radiograph (D), and lateral
clinical photograph (E). The K-wires were removed 8

weeks postoperatively. The patient’s MCP
hyperextension deformity was corrected with MCP
joint arthrodesis of the left index, middle, ring, and
small fingers, shown here 4 months postoperatively
with the fingers in extension (F) and flexion (G).
Small Finger Abduction (Wartenburg Sign) Correction: EDM
Tendon Transfer
■ In a low median and ulnar nerve palsy, the abduction deformity of the small
finger occurs due to the ulnar pull of the EDM on the small finger without
opposition due to the deinnervation of the third palmar interosseous.
■ To correct the ulnar deviation of the small finger, the ulnar half of the EDM
is divided from its insertion on the dorsal proximal phalanx of the small
finger and then passed volar to the deep transverse intermetacarpal ligament
from the dorsal to the volar hand.
■ If there is no clawing, the EDM can be sutured to the insertion of the radial
collateral ligament of the small finger MCP joint.
■ If there is clawing of the small finger, the EDM tendon is passed under the
A2 pulley and sutured back to itself to correct the MCP hyperextension
deformity.
■ High Combined Median and Ulnar Nerve Palsy
Thumb Flexion: BR to FPL Tendon Transfer
■ To restore flexion of the thumb, the BR, ECRL, or ECRB can be transferred
to the FPL.
■ We prefer to use the BR, it is the most expendable of these three tendons;
its harvest results in minimal donor-site morbidity. This reserves the ECRL
for transfer to the FDP for finger flexion and maintains the ECRB as the
only remaining wrist extensor.
■ The ECRB is the preferred wrist extensor to preserve because it is the most
centrally located over the dorsal wrist.
■ Preserving the ECRL only can lead to radial deviation of the wrist with
extension. Similarly, preserving only the ECU can lead to ulnar deviation in
extension.

■ To transfer the BR, an incision is made over the volar-radial distal radius to
identify the insertion of the BR onto the radial styloid as well as the FPL
(TECH FIG 7A).
■ The BR tendon is harvested distally with a 2-cm periosteal extension from
the distal radius to increase its length (TECH FIG 7B).
■ The superficial branch of the radial nerve must be carefully protected; this
nerve is the only source of sensation to the hand in patients with combined
median and ulnar nerve injures.
■ The BR is freed proximally off of the radius to maximize its excursion,
moved volarly, and secured to the FPL proximal to the carpal tunnel (TECH
FIG 7C).
TECH FIG 7 • A. In a patient with a high median nerve
injury, an incision is designed over the volar-radial
distal radius to identify the BR, FPL, and FDP. The BR
is transferred to the FPL to restore thumb flexion. B.
The ECRL (isolated on scissors) is identified for
transfer to the FDP for finger flexion. (Pulling the
ECRL causes wrist extension.) The BR (arrow) is
identified for transfer to the FPL to restore thumb
flexion. C. The BR is secured to the FPL proximal to
the carpal tunnel, restoring thumb flexion.
■ The tendon transfer tension is set with the elbow flexed at 90 degrees, the

wrist in 20 degrees of extension, the forearm fully pronated, and the thumb
pulp and PIPJ of the index finger opposed.9
■ The position of the elbow affects the degree of thumb flexion once the
transfer has healed. When the elbow is extended, thumb flexion is stronger
than when the elbow is flexed.
Finger Flexion: ECRL to FDP Tendon Transfer
■ To restore finger flexion, the ECRL can be transferred to the FDP around the
radial side of the wrist.
■ An incision is made over the dorsal base of the index finger metacarpal to
expose the ECRL insertion (TECH FIG 8A).
■ The ECRL is divided near its insertion and then rerouted subcutaneously
around the radial border of the forearm and sutured into the four FDP tendons
proximal to the carpal tunnel using a second incision (TECH FIG 8B).
■ The tendon transfer is secured to restore the flexion cascade of the digits; the
tension is set progressively tighter from the index to the small finger.
Forearm Pronation: Rerouting the Brachioradialis Tendon
■ Forearm pronation is lost following a high median nerve injury.
■ To re-establish pronation, the biceps tendon insertion can be rerouted around
the neck of the radius.10 Alternatively, the BR can be rerouted and the
interosseous membrane can be released if tight.11
TECH FIG 8 • A. Over the dorsal wrist, an incision is
made to identify the ECRL. The ECRL is rerouted
around the radial wrist and transferred to the FDP to
restore finger flexion. B. The ERCL is secured to the
FDP, restoring flexion of the index, middle, ring, and
small fingers.

■ We prefer to reroute the BR, it is less technically challenging than biceps
rerouting and it provides greater active pronation than other techniques.
■ Biceps rerouting can cause an elbow flexion contracture.
■ To reroute the BR, an incision is made over the volar distal third of the
radius. The BR is elevated off the radius at its distal insertion and elevated
proximally. It is extended 5 cm distally using Z-lengthening.
■ The BR is then passed between the radius and ulna through the interosseous
membrane, proximal to the pronator teres, from volar and ulnar to dorsal and
radial.
■ The elbow is placed in 90 degrees of flexion and the forearm is fully
pronated. The BR tendon is secured to the dorsoradial distal third of the
radius (TECH FIG 9).
Sensory Nerve Transfers
■ In combined median and ulnar nerve injuries, all volar hand sensation is lost.
■ To restore protective sensation, a branch of the superficial radial nerve can
be transferred to the distal median nerve.
■ Alternatively, a first dorsal metacarpal artery flap can be used to provide
sensation to the volar thumb. A branch of the superficial branch of the radial
nerve is contained within this innervated flap.

TECH FIG 9 • To restore forearm pronation, the BR
can be rerouted around the radius. A. The BR tendon
is extended 5 cm distally using Z-lengthening. The BR
is elevated distally from its insertion on the radius,
passed through the interosseous membrane (B), and
then secured to the dorsoradial radius with the elbow
flexed 90 degrees and the forearm in full pronation
(C).
PEARLS AND PITFALLS
Physical
findings
■ Creating a chart is helping in determining an individualized
surgical plan. The patient’s main subjective functional complaints

are listed in the first column. In the second column, the patient’s
objective physical examination deficits are listed. In the third
column, the patient’s intact, innervated tendons are documented;
these are further classified into expendable tendons available for
transfer and nonexpendable tendons that must be preserved to
prevent donor-site morbidity.
■ The donor tendons are then matched to the functional deficits and
the surgical plan is reviewed with the patient.
■ It is beneficial for the patient to meet with a hand therapist prior to
tendon transfer surgery for preoperative teaching; rehabilitation
protocols and expectations are reviewed.
Technique
■ Proper intraoperative tension setting and postoperative
immobilization are necessary to optimize the outcomes of tendon
transfers.
■ Wide-awake surgery using local anesthesia can facilitate
intraoperative assessment of the tendon transfer tension.
Postoperative
■ The joints crossed by the tendon transfer are immobilized for 4
wk.
■ ROM exercises for the shoulder and unaffected joints of the upper
extremity should be resumed immediately postoperatively to
minimize stiffness.
Therapy
■ Some authors advocate for early active ROM exercises following
tendon transfers secured with 3 Pulvertaft weaves to minimize
adhesions. In these cases, tendon gliding exercises are started on
postoperative day 2 under the guidance of a hand therapist.12
POSTOPERATIVE CARE
■ Following a tendon transfer, we prefer to immobilize the affected joints for 4
weeks to permit tension-free tendon healing; casting or splinting is used.
■ Above elbow immobilization is used in transfers crossing the elbow. For
example, for the BR to FPL transfer, immobilization holds the elbow in 90
degrees of flexion and the wrist slightly flexed or in neutral. Following tendon
transfers to correct clawing, the MCP joints are immobilized in flexion and the
IP joints in extension.
■ ROM exercises are started 4 weeks postoperatively, starting with active ROM
and followed by passive ROM. Mobilizing one joint at a time minimizes
tension on the tendon transfer.
■ 6 weeks postoperatively, muscle retraining and resistance exercises begin.

■ 8 weeks following surgery, strengthening exercises begin and splints are
weaned.
■ At 12 weeks postoperatively, free unrestricted activity can be resumed.
OUTCOMES
■ The balance of the flexors and extensors of the hand and wrist is critical for
optimal function.
■ The transfer of radial nerve-innervated hand and wrist extensors to restore
hand and wrist flexion aids in restoring the function of the hand by re-
establishing active hand and wrist flexion while weakening hand and wrist
extension, improving the overall balance of the hand and wrist.
COMPLICATIONS
■ Thorough discussion with the patient, careful physical examination, and
thoughtful planning are required to optimize the function of the upper
extremity following combined median and ulnar nerve injuries.
■ The patient is counseled that his or her volar and dorsoulnar hand will remain
insensate following tendon transfers. Worse outcomes are seen in patients with
decreased sensation compared to those with intact sensation. Following
sensory nerve injury, visual and auditory cues are required to permit the patient
to use their injured hand; tactile sensory feedback is absent. Sensory nerve
transfers can be performed to restore protective sensation. Ideally, nerve repair
at the time of the injury is performed to permit motor and sensory recovery
over time.
■ Transferred tendons can rupture if placed under excess tension, if inadequately
sutured during surgery, and if not sufficiently immobilized after surgery. If
rupture occurs, immediate exploration and primary repair are recommended.
■ Adhesions frequently form where tendons cross each other and in scarred
tissue beds. Frequent, intensive hand therapy is used to optimize passive ROM
in these cases. If passive ROM exceeds active ROM, a tenolysis may be
beneficial. Tenolysis is performed no sooner than 3 months following the
tendon transfer. Patient compliance is critical; daily hand therapy exercises are
started 2 days after tenolysis to maintain intraoperative active ROM gains.
■ Multiple long incisions are used for tendon transfers; patients must be
counseled about postoperative scarring prior to reconstruction. Postoperatively,
scar massage and sun avoidance are recommended for scar management.
REFERENCES

1. Erdem HR, Ergun S, Erturk C, Ozel S. Electrophysiological evaluation of the
incidence of martin-gruber anastomosis in healthy subjects. Yonsei Med J.
2002;43(3):291-295.
2. Kazakos KJ, Smyrnis A, Xarchas KC, et al. Anastomosis between the median
and ulnar nerve in the forearm: an anatomic study and literature review. Acta
Orthop Belg. 2005;71(1):29-35.
3. Kimura I, Ayyar DR, Lippmann SM. Electrophysiological verification of the
ulnar to median nerve communications in the hand and forearm. Tohoku J Exp
Med. 1983;141(3):269-274.
4. Pulvertaft RG. Suture materials and tendon junctures. Am J Surg.
1965;109:346-352.
5. Gonzalez MH, Weinzweig N, Kay T, Grindel S. Anatomy of the extensor
tendons to the index finger. J Hand Surg [Am]. 1996;21(6):988-991.
6. Jones NF, Machado GR. Tendon transfers for radial, median, and ulnar nerve
injuries: current surgical techniques. Clin Plast Surg. 2011;38(4):621-642.
7. Coleman SS, McAfee DK, Anson BJ. The insertion of the abductor pollicis
longus muscle; an anatomical study of 175 specimens. Q Bull Northwest Univ
Med Sch. 1953;27(2):117-122.
8. Thwin SS, Fazlin F, Than M. Multiple variations of the tendons of the
anatomical snuffbox. Singapore Med J. 2014;55(1):37-40.
9. Fridén J, Reinholdt C, Gohritz A, et al. Simultaneous powering of forearm
pronation and key pinch in tetraplegia using a single muscle-tendon unit. J
Hand Surg Eur Vol. 2012;37(4):323-328.
10. Zancolli EA. Paralytic supination contracture of the forearm. J Bone Joint
Surg Am. 1967;49(7):1275-1284.
11. Ozkan T, Aydin A, Ozer K, et al. A surgical technique for pediatric forearm
pronation: brachioradialis rerouting with interosseous membrane release. J
Hand Surg [Am]. 2004;29:22-27.
12. Sultana SS, MacDermid JC, Grewal R, Rath S. The effectiveness of early
mobilization after tendon transfers in the hand: a systematic review. J Hand
Ther. 2013;26(1):1-20.

35
CHAPTER
Distal Anterior Interosseous
Nerve Transfer to Motor
Branch of Ulnar Nerve
Shelley S. Noland and Jason H. Ko
DEFINITION
■ Ulnar nerve palsy severely limits hand function with loss of dexterity, pinch
and grip strength weakness, and claw formation.
■ Ulnar-innervated intrinsic muscle recovery after high ulnar nerve injury
(above elbow) is poor.
■ Distal transfer of the anterior interosseous nerve (AIN) to the motor
component of the ulnar nerve can preserve motor endplates and restore motor
function.
ANATOMY
■ Ulnar nerve
■ After exiting the cubital tunnel, the ulnar nerve enters the forearm between
the two heads of the flexor carpi ulnaris (FCU).
■ It travels between the FCU and flexor digitorum profundus (FDP) muscles
and gives off the dorsal sensory branch 9 cm proximal to the wrist crease.
■ At the Guyon canal, it enters the hand and divides into the deep motor branch
and the sensory branch.
■ Internal topographical anatomy
• Topographical anatomy is critical to the success of this procedure.
• The ulnar nerve has a discrete fascicular pattern.
• At the level of the mid-forearm, the three components are the ulnar-sided
sensory component (dorsal sensory branch), the middle motor component
(intrinsic motor function), and the radial-sided sensory component (digital
ulnar sensation) (FIG 1).

■ Median nerve
■ After exiting from underneath the lacertus fibrosus, the median nerve travels
through the pronator teres.
■ It courses between the flexor digitorum superficialis (FDS) and the FDP and
gives off four motor branches in the proximal forearm.
■ It enters the hand at the carpal tunnel and divides into the recurrent motor
branch and sensory branches.
■ Anterior interosseous nerve
• Branches from the median nerve 3 cm distal to the intercondylar line
• Contains fascicles to the flexor pollicis longus (FPL), FDP (index and
middle finger), and pronator quadratus (PQ)
• Exits the median nerve on the dorsal radial aspect (FIG 2)
FIG 1 • Internal topography of the ulnar nerve. A,
anterior; P, posterior; L, lateral; R, radial; M, medial; U,
ulnar.

FIG 2 • Internal topography of the median nerve. A,
anterior; P, posterior; L, lateral; R, radial; M, medial; U,
ulnar.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ History
■ Elicit history of trauma, tumor, or other injury to the ulnar nerve or elbow.
■ Elicit location, timing, frequency, and duration of sensory symptoms
including numbness and tingling. Elicit correlation with elbow flexion
activities (driving, talking on the phone, sleeping).
■ Elicit complaints of weakness or “clumsiness” in the hands, particularly with
regard to opening jars, turning door handles, and fine motor tasks.
■ Rule out other causes of symptoms such as cervical spine, shoulder, or
brachial plexus issues.
■ Physical Examination
■ Sensory disturbances typically involve the dorsal and volar ulnar palm, ulnar
half of the ring finger, and small finger.
■ Perform full sensory exam of bilateral upper extremities documenting two-
point discrimination and/or Semmes-Weinstein monofilament testing in all