Clinical Outcomes of Limited Open Intramedullary Headless Screw Fixation (IMHS) of Metacarpal Fractures - 91 Consecutive Patients

Purpose: To evaluate clinical and radiographic outcomes in patients treated with limited-open retrograde intramedullary headless compression screw (IMHS) fixation for metacarpal neck and shaft fractures.

Methods: Retrospective review of prospectively collected data of a consecutive series of 91 patients (79 men; 12 women), mean age 28 years (range, 15y-69y) treated with IMHS fixation for acute displaced metacarpal neck (N = 56) and shaft (N = 35) fractures at a single academic hand practice between 2010 and 2017. 56 patients reached minimum 3-month follow-up. Mean follow-up was10 months (range, 1 to 71 months). Preoperative mean magnitude of metacarpal neck angulation was 47⁰ (range, 0⁰ -90⁰ ), and mean shaft angulation was 42⁰ (range, 0⁰ -70⁰ ). Active motion was initiated within 5 days postoperatively. Clinical outcomes were assessed with digital goniometry and grip strength. Time to radiographic union and radiographic arthrosis was assessed.

Results: All 91 patients achieved full composite flexion (pad-to-distal palmar crease distance = 0mm), and all achieved full active MCP extension or hyperextension. Postoperatvie mean MCP joint flexion-extension arc was 88⁰ (range, 55⁰-110⁰). Only 3 patients did not obtain great than 65⁰ of isolated MCP flexion. Grip strength measured 103% (range, 58% to 230%) of the contralateral hand. 52 patients achieved radiographic union by 6 weeks (range, 2-12 weeks). At latest follow-up, early arthrosis was noted only in 1 patient (head split component). There were 3 cases of shaft re-fracture after recurrent blunt trauma, following prior evidence of full osseous union with the screw in place, necessitating revision with open reduction and plate-screw fixation.

Conclusions: Limited open retrograde IMHS fixation proved to be safe and reliable for metacarpal neck/subcapital and axially stable shaft fractures, allowed for early postoperative motion without affecting union rates, and obviated immobilization. This technique offers distinct advantages over formal open reduction and percutaneous K-wire techniques.

Type of study/level of evidence Therapeutic IV

Key words - Metacarpal fracture, hand trauma, headless screw, intramedullary fixation, minimally invasive surgery, clinical outcome