Introduction Caused by imbalance between strong extrinsics and deficient intrinsics Characterized by MCP hyperextension PIP & DIP flexion Causes ulnar nerve palsy cubital tunnel syndrome ulnar tunnel syndrome median nerve palsy Volkmann's ischemic contracture leprosy (Hansen's disease) failure to splint the hand in an intrinsic-plus posture following a crush injury Charcot-Marie-Tooth disease (hereditary motor-sensory neuropathy) compartment syndrome of the hand Pathoanatomy Pathoanatomic components loss of intrinsics leads to loss of baseline MCP flexion and loss of IP extension strong extrinsic EDC leads to unopposed extension of the MCP joint remember the EDC is not a significant extensor of the PIP joint most of the MCP extension forces on the terminal insertion of the central slip come from the interosseous muscles strong FDP and FDS leads to unopposed flexion of the PIP and DIP Presentation Symptoms decreased hand function Physical exam MCP hyperextension and IP joint flexion with an ulnar nerve palsy, the deformity will be worse in the 4th and 5th digits (lumbricals innervated by the ulnar nerve) not as severe in the 2nd and 3rd digits (lumbricals innervated by the median nerve) functional weakness unable to perform prehensile grasp diminished grip and pinch strength provocative tests if MCP joints are brought out of hyperextension, the flexion deformity of the DIP & PIP will correct Treatment Operative contracture release and passive tenodesis vs. active tendon transfer indications progressive deformity that is affecting quality of life technique goal is to prevent MCP joint hyperextension
QUESTIONS 1 of 2 1 2 Previous Next (OBQ04.33) Extrinsic imbalance from splinting a crushed hand with metacarpophalangeal joint extension causes what characteristic hand deformity? Review Topic QID: 94 1 Distal interphalangeal joint extension 3% (64/2172) 2 Ulnar subluxation of the metacarpophalangeal joints 2% (47/2172) 3 Proximal interphalangeal joint extension 12% (259/2172) 4 Proximal interphalangeal joint flexion 73% (1593/2172) 5 Swan-neck deformity 9% (200/2172) ML 2 Select Answer to see Preferred Response PREFERRED RESPONSE 4 (SBQ11UE.1) A 40-year-old male sheet metal worker sustained a crush injury to his hand. His hand was treated in a short arm splint after closed reduction and percutaneous pinning of multiple metacarpal fractures. The patient’s fractures healed uneventfully however, he presented six months later with the deformity shown in Figure A. What pathoanatomic process is responsible for his deformity? Review Topic QID: 4236 FIGURES: A 1 Volar plate laxity and tethering of the lateral bands at the proximal interphalangeal joints 3% (117/4245) 2 FDP laceration distal to the origin of the lumbricals 1% (41/4245) 3 Adhered FDP tendon of the middle finger 1% (37/4245) 4 Imbalance between spastic intrinsics and weak extrinsics 17% (739/4245) 5 Imbalance between strong extrinsics and deficient intrinsics 77% (3288/4245) ML 2 Select Answer to see Preferred Response PREFERRED RESPONSE 5