A Biomechanical Comparison of Extensor Carpi Ulnaris Subsheath Reconstruction Techniques.

PURPOSE: Several surgical stabilization techniques have been described to address pathological subluxation of the extensor carpi ulnaris (ECU) tendon, with no comparative data available. This study compares ECU stability after subsheath reconstruction, with and without ulnar groove deepening, to stability with an intact subsheath in a cadaveric model. METHODS: Position of the ECU tendon relative to the ulnar groove was measured in 5 human cadaveric specimens with the subsheath intact, sectioned, and after 3 reconstruction scenarios: reconstructed, reconstructed with ulnar groove deepened, and ulnar groove deepened with subsheath sectioned. Position of the tendon relative to the radial side of the ulnar groove was recorded with digital calipers in 9 combinations of wrist/forearm positions (wrist flexion, extension, and neutral; forearm pronation, supination, and neutral). Dislocation events, defined as the tendon being completely ulnar to the groove, were recorded. RESULTS: Extensor carpi ulnaris tendon displacement was not significantly different between intact subsheath, subsheath reconstruction, and reconstruction with groove deepening (1.5 mm vs 0.5 mm vs -0.3). Extensor carpi ulnaris tendon displacement after groove deepening with the subsheath sectioned was not significantly different from displacement with a fully sectioned subsheath. Sectioning of the subsheath induced dislocation events of the ECU tendon in multiple positions. Subsheath reconstruction with and without groove deepening allowed no dislocation events. CONCLUSIONS: In this cadaveric model, groove deepening did not improve stability of the ECU tendon compared with the reconstructed subsheath, and reconstruction alone was equally effective at eliminating dislocation events. CLINICAL RELEVANCE: Stabilization techniques that focus on restoration of the important ulnar attachment of the ECU subsheath are favored over routine deepening of the ulnar groove in attempts to stabilize the ECU tendon.

Importance of Computed Tomography in Determining Displacement in Scaphoid Fractures.

Background Displaced scaphoid fractures have a relatively high rate of nonunion. Detection of displacement is vital in limiting the risk of nonunion when treating scaphoid fractures. Questions/Purpose We evaluated the ability to diagnose displacement on radiographs and computed tomography (CT), hypothesizing that displacement is underestimated in assessing scaphoid fracture by radiograph compared with CT. Materials and Methods Thirty-five preoperative radiographs and CT scans of acute scaphoid fractures were evaluated by two blinded observers. Displacement and angular deformity were measured, and the fracture was judged as displaced or nondisplaced. Scapholunate, radiolunate, and intrascaphoid angles were measured. Radiograph and CT measurements between nondisplaced and displaced fractures were compared. Intraobserver reliability was measured. Results Reader 1 identified 12 fractures as nondisplaced on radiograph, but displaced on CT (34%). Reader 2 identified 9 fractures as nondisplaced on radiograph, but displaced on CT (26%). For displaced fractures, the mean intrascaphoid angle was over three times greater when measured on CT than on radiograph (56 vs. 16 degrees). Scapholunate angle >65 degrees and radiolunate angle >16 degrees were significantly associated with displacement on CT. Interobserver reliability for diagnosing displacement was perfect on CT but less reliable on radiograph. Conclusion Scaphoid fracture displacement on CT was identified in 26 to 34% of fractures that were nondisplaced on radiograph, confirming that radiographic evaluation alone underestimates displacement. These results underscore the importance of CT scan in determining displacement and angular deformity when evaluating scaphoid fractures, as it may alter the decision on treatment and surgical approach to the fracture. We recommend considering CT scan to evaluate all scaphoid fractures. Level of Evidence Level III.

Diagnosis, Treatment, and Return to Play for Four Common Sports Injuries of the Hand and Wrist.

Hand and wrist injuries in the high-level athlete are challenging because they may be underestimated by the patient, family, and team, and return to play may be longer than desired. The needs of the player and the team must be balanced with the long-term functional ramifications of the injury. Four common soft-tissue sports injuries are flexor digitorum profundus avulsion, flexor pulley rupture, extensor carpi ulnaris dislocation, and thumb metacarpophalangeal joint ulnar collateral ligament injury. For each of these injuries, the assessment, treatment, and considerations for return to play should be individualized on the basis of the patient, the sport, and the timing of the injury.