CMC joint fracture dislocation: carpo-metacarpal
．high energy
．5th CMC: associated ulnar nerve injury
．3rd CMC: deep palmar archs
．shortening of Metacarpal bone
．Brewerton view: evaluate metacarpal base: 60 degree CMC joint flexion
．CT if suspected carpal bone fracture
Pure CMC dislocation
．rare
．evaluate its stability
Thumb CMC fx dislocation
．partial: Bennett’s fx, Complete: Rolando’s fx
．Thumb CMC: intermetacarpal lig, volar & post oblique lig, dorsoradial lig
．Pinning for thumb base fx:
(1) radial a
(2) superficial radial and lateral antebrachial n.
(3) extensor tendon (APL, EPB, EPL)
．Deforming force:
(1) APL: extension force in thumb metacarpal base (toward proximal & radial side)
(2) Adductor Pollicis: adduction force on thumb metacarpal head (adduction and rotation)
Non-OP Treatment
．stable, minimally displaced fx
．for displaced fx: poor satisfactory outcome,
．malrotation, varus deformity, arthritic change
Operative treatment
．CRIF: current strategy
．restore length, maintain reduction, at least 6 weeks
．ORIF: for delayed operation
Pure CMC dislocation
．reconstructed with FCR
Thumb CMC fx-dislocation
．Bennett’s > Rolando
．Step-off < 1mm, no difference in its outcome between CRIF or ORIF
．CRIF: more adduction contracture
．complex Rolando: severe comminution (complex operation for orthopaedic surgeon without subspeciality, minimal open + external fixation)
Author’s preference:
Pure thumb CMC dislocation
．immediate ligament reconstruction: not suggested
．primary capsule repair with 1.3mm bone anchor
Bennett’s fracture
．two pins: one toe trapezium, one to index metacarpal
Rolando’s
．distraction and maintaining length
．maintaining length: .062 wire fixed on 2nd metacarpal
．Plate & screw: early range of motion, adhesion to EPL, EPB may result in limitation of ROM
．Approach: Wagner’s incision (Incision → reflect thenar muscle → expose APL → arthrotomy
Complication: hypersensitivity
．small nerve fiber branch injury during trauma or operation
．neuroma formation
．Medication: Gabapentin, Amitryptyline
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