Aetiology
High Lesion
- elbow fracture or dislocation
- forearm fracture
- penetrating forearm wound
Low Lesion
- laceration at wrist
- distal radius fracture
- carpal dislocation
- entrapment in carpal tunnel
Clinical Features
1. Low Lesion
A. Loss Thumb function
- paralysis of APB & Opponens
- variable FPB
- 1/3 have enough opponens power not to need transfer
B. Parasthesia Radial 3 1/2 fingers and palm
2. High Lesion
Above +
C. Loss flexion index and middle finger
- lose FDS IF / MF / RF / LF
- lose FDP to IF / MF
D. Unable to flex thumb IPJ
- FPL
E. FCR + PT
3. Anterior Interosseous Nerve Palsy
Benediction sign
- loss FDP & FPL
- index finger and thumb straight
- middle finger is flexed due to quadriga of MF / RF
Weakness of pronation
- pronator quadratus
No thenar weakness or sensory loss
Management
- thumb: BCR to FPL
- IF / MF: FDP buddy to RF / LF / ECRL to FDP / fuse DIPJ
Management
Initial
Open injury
- Explore & repair
Closed injury
- Reduce fracture or dislocation
- Explore if fails to improve after 3/12
- NCS / EMG first
Physiotherapy
Maintain Joint ROM / Prevent Contractures
Goals
1. Flexion IF / MF
- ECRL to FDP IF / MF
2. Flexion RF / MF
- fusion DIPJ or
- buddy to RF / LF FDP
3. Thumb IPJ flexion
- BR to FPL
4. Thumb Opposition
- EI to APB or
- RF FDS to APB
4. Sensation thumb & radial side IF
- for pinch grip
Oppensplasty
High median nerve / Extensor indicis to APB
Harvest EIP
- incision over index MCPJ
- EIP divided with some extensor hood
- hood repaired
2nd incision over dorsum of hand
- free EIP from EDC
Incision over dorsoulnar wrist
- displace tendon ulnarward
- tendon passed subcutaneously ulnar aspect of wrist to pisiform which acts as a pulley
Tunnel across palm to thumb MCPJ
- interwoven into APB & EPL tendon
Low Median Nerve / Opponensplasty with RF FDS
Reason
- have strong Adductor Pollicis / 1st dorsal interosseous / EPL
- they will overpower a weak transfer
Technique
- loop of FCU at pisiform for pulley for donor
- pass donor through loop
- tunnel subcutaneously across palm & attach to tendon APB