Retrospective Comparison of Capitolunate Arthrodesis Using Headless Compression Screws Versus Nitinol Memory Staples for SLAC and SNAC Wrist: Radiographic, Functional, and Patient-Reported Outcomes.

Background: Nitinol memory compression staples have been proposed as an effective alternative to compression screws for capitolunate arthrodesis (CLA) for scaphoid nonunion advanced collapse (SNAC) and scapholunate advanced collapse (SLAC) wrist. The purpose of this study was to compare the clinical outcomes of CLA for SNAC or SLAC wrist treatment using either compression screws or nitinol staples.
Methods: In all, 47 patients with CLA for SLAC or SNAC wrist with screws or nitinol staples were retrospectively identified. Primary outcome was fusion on radiographs and/or computed tomography. Secondary outcomes were hardware-related complications (HWCs) and other complications, range of motion, grip strength, and patient-reported outcome measures (PROMs), including Visual Analogue Pain scale; Disabilities of the Arm, Shoulder, and Hand score; and patient-rated wrist evaluation.
Results: Of the 47 eligible patients, 40 (85%) were included: 31 patients in the staple group and 9 patients in the screw group. The average age was 49 (17-80) years. There was an 89% union rate for the screw group and a 97% union rate for the staple group. Two patients had screw backout: one who went onto union after screw removal and the other who went onto nonunion after hardware removal. There were 2 (6.5%) HWCs in the staple group. One patient had staple loosening requiring revision and the other dorsal impingement requiring staple removal after radiographic union. In all subsequent cases, the staples were countersunk with no impingement. No significant differences existed between any additional outcomes.
Conclusions: We found no differences between nitinol staples and screws for CLA regarding HWCs or PROMs. Nitinol staples may offer additional benefits as a safe and effective alternative to compression screws for wrist fusions.