Review Question - QID 3475

The clinical situation is consistent with midcarpal instability. The most common finding on physical examination is a clunk as the wrist is moved from a neutral position and forearm pronation to ulnar deviation with an axial and palmarly directed load. Carpal instability is complex condition marked by abnormal kinematics in the carpus. Carpal instability dissociative (CID) is marked by intrinsic ligamentous disruption. Carpal instability non-dissociative (CIND) is marked by extrinsic ligamentous disruption between carpal rows or between the proximal row and distal radius. Included in CIND is midcarpal instability (MCI) and radiocarpal instability. Radiographs typically show a mild VISI deformity or no abnormalities as in Figures A and B. Videofluorscopy is diagnostic as the proximal row assumes a volar, flexed position, then snaps into extension the wrist is moved into ulnar deviation.

Lichman et al provided an overview and historical perspective of carpal instability. Carpal instability is divided into dissociative and non-dissociative. They concluded that there are several causes and patterns of carpal instability leading to carpal subluxation. An in-depth understanding is required for proper treatment.

Apergis et al described 14 cases of midcarpal instability treated with ligamentous reefing of the midcarpal joint and or the radiolunate joint. They reported excellent results in eight cases, good in five cases, and fair in one case.

Incorrect answers:
Answer 1: A positive Finkelstein's maneuver is radial-sided pain with a clinched thumb and ulnar deviation of the wrist
Answer 2: A positive Fovea sign is found with pain on palpation distal to the ulnar styloid
Answer 3: Watson's scaphoid shift is pain and a clunk on ulnar to radial deviation of the wrist while pressure is held on the scaphoid tubercle.
Answer 4: Describes pain in the lunate as in Keinbock's.