PATIENT OUTCOMES FOLLOWING REDUCTION AND ASSOCIATION OF THE SCAPHOID AND LUNATE

Scapholunate lunate ligament (SLL) injury is the most common ligamentous injury of the wrist; however, the optimal surgical management remains unclear [1,2]. One promising technique for SLL reconstruction is the Reduction and Association of the Scaphoid and Lunate procedure (RASL), first described by Rosenwasser [3]. Despite promising preliminary outcomes by the creator [4], the outcomes of this procedure remain variable [5]. The objective of this retrospective analysis was to investigate factors affecting patient outcomes following the RASL procedure. Twenty-three patients who had a SLL tear treated with a RASL using a dual-incision approach as described by Rossenwasser [3] completed the data collection process. Participants completed a demographic survey and three standardized patient-reported outcome tools (DASH, PRWE and PROMIS questionnaires). Standard wrist radiographs were taken, and bilateral wrist range-of-motion and grip strength were measured. The scapholunate interval, scapholunate angle, radioscaphoid angle, radiolunate angle were measured preoperatively, intraoperatively, and at long-term follow up. The intraoperative images were used to assess screw placement. All measurements were taken by the primary author and independently verified by two board-certified hand surgeons. The average time since surgery was 6.3 years, with a minimum time since surgery of 2.2 years and a maximum of 11.1 years. The average age was 36.2 (SD 11) years at the time of injury. At the time of final follow-up, the average DASH score was 11.2 (SD 13). There was no correlation between DASH score and preoperative scapholunate angle (R² = 0.056), screw angle (R² = 0.061), or time from surgery (R² = 0.014). The average screw angle measured our intraoperative radiographs was 15.2° (SD 6.3°). At time of final follow-up, 4 participants had undergone a second surgery for screw removal and 1 participant was converted to a four-corner fusion for persistent pain. The average preoperative scapholunate gap was 5.0 mm in the group who had a second surgery (n =5) compared to 3.0 mm in the group with no revision surgery (n =18). The average screw angle measured our intraoperative radiographs falls below the target angle of 23°; however, we did not find a correlation between screw angle and patient-reported outcomes. Possible factors contributing to patient outcomes include severity of the injury as measured by pre-operative scapholunate gap. We conclude that patients can have exceptional outcomes following the RASL, but larger scale studies are required to identify patient and injury-related factors to select good candidates.