Upper limb: Tendon transfers

Question 1

What are the general principles of successful tendon transfer?

Answer 1

1. Patient selection:
   - well motiviated
   - understands nature and limitations of surgery
   - co-operates with HT/OT
2. Recipient site factors:
   - good soft tissue cover
   - stable skeletal base
   - full range of passive movement of the joint
   - normal sensation
3. Donor site muscle factors:
   Factors to consider when choosing which muscle to transfer (APOSLE)
   A: amplitude of motion - donor muscle should have a similar excursion to what it replaces.
   - wrist flexors and extensors 3cm
   - finger extensors 3cm
   - finger flexors 7cm
   Amplitude increased by freeing fascial tethers and tenodesis effect (amplitude of a tendon that crossed the wrist is increased by 2-3cm by full wrist ROM)

P: power and control - donor muscle must be similar strength to what replaces.
- muscles lose at least one motor grade after transfer
- if MRC 3 or less - > probably wont do well.
- donor muscles should be under voluntary control
- some muscles (eg brachioradialis) have difficulty adapting to a new function

O: one tendon one function

S: Synergistic action
- finger flexion usually accompanies by wrist extension
and vice vera
- synergistic transfers require shorter period of rehabilitation

L: line of pull - transfers function best when travel in a straight line - deviation around a pulley will weaken the transfer

E: Expendability - only use expendable muscles. Must preserve a wrist flexor when reconstruction of wrist and finger extension post-radial palsy

Question 2

What are the motor deficits in a radial nerve palsy?

Answer 2

1. reduced wrist extension
2. reduced finger extension
3. reduced thumb abduction and extension

Question 3

What tendon transfers could be considered in a radial nerve palsy?

Answer 3

Classic transfer:
1. PT to ECRB
2. FCU o EDC
3. PL to EPL

Superficialis transfer:
1. PT to ECRL and ECRB
2. FDS of Middle to EDC
3. FDS of Ring to EIP and EPL
4. FCR to APL and EPB

Question 4

What are the motor deficits in a median Nerve palsy?

Answer 4

1. thumb opposition (denervation of thenar eminence)
2. APB (thenar muscle most reliably supplied by median nerve)
3. FPB and opponens pollicis are often partially supplied by Ulnar nerve
   (some pt with low median nerve palsies still have adequate thumb opposition)

Question 5

What are the tendon transfers that could be considered in a median nerve palsy?

Answer 5

1. restoration of thumb opposition (opponensplasty). 4 main types:

a. The Royle-Thompson Opponsplasty - FDS ring is divided at distal attachment, tendon passed superficially through palmar fascia at which point it pivots before crossing palm, the attached onto insertions of EPB or APB.

b. EI transfer: EI re-routed around ulnar site of hand and inserted into APB or EPB.

c. The Camitz transfer: PL lengthened with strip of palmar fascia and attached to insertion of APB. (useful if longstanding palsy and often combined with CTR in older patients)

d. Huber transfer: Abductor digiti miminim detached distally and elevated, preserving proximal NV supply, then transposed across palm and inserted into insertion of APB ro EPB

Question 6

What are the motor deficits associated with an ulnar nerve palsy?

Answer 6

1. Adductor pollicis (weak thumb adduction)
2. weak finger abduction (dorsal interossei)
3. Weak finger adduction (palmar interossei)
4. Ulnar clawing (hyperextension of MCPJ and flexion IPJ)

Question 7

What are the options for tendon transfer to consider in an ulnar nerve palsy?

Answer 7

1. Restoration of thumb adduction:
   a. FDS middle or ring detach distally and attach to insertion adductor policis
   b. ECRB lengthened with tendon graft and inserted onto adductor tubercle of thumb
   c. Brachioradialis extension with tendon graft, passed into palm from dorm through 3rd webspace. Attached to insertion of adductor policis
2. Correction of Claw deformity: any technique which limits MCPJ hyperextension will control the claw deformity.
   Lots of techniques.
   Static vs Dynamic
   a. STATIC: Omers modification of Zancollis lasso technique:
   A1 pulley released
   Trapdoor made in volar plate MCPJ (distally based flap)
   Place MCPJ in 20 deg flexion, secure middle part of volar plate to MC bone through transosseous tunnel.

b. DYNAMIC: to get MCPJ flexion +/- IPJ extension. Various donors and techniques including FDS, ECRB, ECRL

Question 8

Describe the dynamic techniques for ulnar claw correction

Answer 8

Techniques for insertion:
1. direct into lateral bands
2. direct into P1 bone shaft
3. Lassoo around A2 pulley

FDS transfer
- can use multiple tendons or split into many tails
- risk of swan neck

ECRB transfer
- augmented with PL or planters graft
- extensor route
- volar to deep transferse inter metacarpal ligaments
- insert into radial lateral bands of middle, ring and little finger

ECRL transfer
- augment with tendon graft
- volar route through carpal tunnel
- insert into ulnar lateral band index and radial lateral band middle, ring and little

Key pinch restoration
- ECRB to adductor pollicis (with tendon graft)
- APL tendon slip into index finger insertion of first dorsal interosseous with tendon graft

High under nerve lesion
-buddy ulnar FDP to middle FDP -will get a weaker grip though
-transfer middle FDS to ulnar FDP
- can consider transfer FCR to FCU if specific functional requirement