Dynamic assessment of wrist after proximal row carpectomy and 4-corner fusion.

PURPOSE: To investigate the effect of 4-corner fusion (4CF) or proximal row carpectomy (PRC) on wrist motion, strength, and outcome for 2 different cohorts from 2 separate institutions performing either 4CF or PRC for stage 2/3 scaphoid nonunion advanced collapse and scapholunate advanced collapse. METHODS: The researchers assessed 46 subjects (24 4CF and 22 PRC), mean age 54 years, with a flexible electrogoniometer to measure maximum wrist motion and circumduction and compare it with the nonsurgical wrist. We analyzed the shape, size, rate, and smoothness of the circumduction curves. We assessed the maximum grip and sustainability of grip for 60 seconds using a digital grip analyzer. Patient evaluation measure and Michigan Hand Questionnaires measured patient-reported outcomes. RESULTS: Flexion-extension in the surgically treated wrist was 50% of the nonsurgical side after a 4CF and 65% after a PRC. The radioulnar deviation component in circumduction of the surgically treated wrist was similar but markedly decreased after either procedure. The mean area of circumduction of the surgically treated wrist was similar after a PRC and a 4CF but was 30% of the nonsurgical wrist. The center of the circumduction ellipse after a PRC was closer than after a 4CF to the opposite wrist. The orientation of the plane of circumduction was 22° to the vertical flexion-extension plane after a PRC. After a 4CF, the plane was more vertical (9°). The peak grip strength and the area under the force time curve was 80% of the nonsurgical side after a PRC and 60% after a 4CF. The Michigan Hand Questionnaire result was 90% of the score for the nonsurgical hand after a PRC and 75% of score for the nonsurgical hand after a 4CF. CONCLUSIONS: The PRC provided improved flexion-extension with a circumduction curve concentric with the nonsurgical wrist. The 4CF limited extension and ulnar deviation more than did a PRC. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

A four-dimensional-CT study of in vivo scapholunate rotation axes: possible implications for scapholunate ligament reconstruction.

Additional fixation of the palmar scapholunate interosseous ligament has been advocated to improve the long-term results of dorsal scapholunate interosseous ligament reconstruction. To investigate the validity of this approach, we determined normal scapholunate motion patterns and calculated the location of the scapholunate rotation axis. We hypothesized that the optimal location of the scapholunate interosseous ligament insertion could be determined from the scapholunate rotation axis. Four-dimensional computerized tomography was used to study the wrist motion in 21 healthy participants. During flexion-extension motions, the scaphoid rotates 38° (SD 0.6°) relative to the lunate; the rotation axis intersects the dorsal ridge of the proximal pole of the scaphoid and the dorsal ridge of the lunate. Minimal scapholunate motion is present during radioulnar deviation. Since the scapholunate rotation axis runs through the dorsal proximal pole of the scaphoid, this is probably the optimal location for attaching the scapholunate ligament during reconstructive surgery.