Purpose: Although injury to the collateral ligaments of the metacarpophalangeal joint (MPJ) of the fingers is less common than corresponding injuries in the thumb, similar disability may result from chronic untreated injuries. We evaluated injury characteristics and the outcome after primary repair of subacute to chronic grade III collateral ligament injuries of the MPJs of the fingers.
Methods: We retrospectively reviewed all patients who underwent primary repair of a finger MPJ collateral ligament over a 3-year period. Twenty-five digits in 23 patients with subacute to chronic injuries were identified, all of which had complete MPJ collateral ligament tear. Postoperatively, we assessed disability using DASH scores and evaluated joint stability, range of motion, and grip strength. These measures were compared to preoperative data to assess results. Post hoc analysis was used to compare the level of disability between index and small radial collateral ligaments and other finger CL injuries.
Results: Intraoperative findings revealed complete tears in all cases and all ligaments were of sufficient quality to permit primary repair using a suture anchor. The average preoperative DASH score was 40 (range 17-77) in 7 patients (nine fingers) where this was available. Postoperative DASH scores were available in 19 patients (21 fingers). The average postoperative DASH score was 19 (range 0-65). In the subgroup of patients with preoperative and postoperative DASH scores, there was no statistically significant difference after surgery (preop DASH 39.1 vs. postop DASH 23.8, p = 0.17). The average grip strength as a percentage of the contralateral hand was 68 % (range 32-100 %). The average postoperative MPJ arc of motion was 75° (range 50-90°). Post hoc analysis showed statistically significant higher postoperative DASH scores among small finger RCL repairs compared to other finger CL repairs (p = 0.007).
Discussion: Primary repair of complete MPJ collateral ligament injuries of the fingers may be performed in the subacute to chronic setting. Although joint stability was restored, patients continued to have decreased grip strength and residual disability.
Keywords: Collateral ligament; Finger; Metacarpophalangeal joint.