Three cast techniques for the treatment of extra-articular metacarpal fractures. Comparison of short-term outcomes and final fracture alignments.

BACKGROUND: Most extra-articular metacarpal fractures can be managed nonoperatively. While the conventional wisdom is that the metacarpophalangeal joint should be immobilized in a position of flexion, alternative methods for cast immobilization have been described. The purpose of this study was to retrospectively evaluate three methods of closed treatment; specifically, we investigated whether the position of immobilization of the metacarpophalangeal joint or the absence of a range of motion of the interphalangeal joints affected the short-term outcome or fracture alignment.

METHODS: Between November 2000 and April 2004, extra-articular metacarpal fractures were immobilized for five weeks in one of three ways: with the metacarpophalangeal joints in flexion and full interphalangeal joint motion permitted (Group 1); with the metacarpophalangeal joints in extension and full interphalangeal joint motion permitted (Group 2); and with the metacarpophalangeal joints in flexion, the interphalangeal joints in extension, and no interphalangeal joint motion permitted (Group 3). Radiographs and the range of motion were evaluated at five weeks after application of the cast, and the range of motion and grip strength were assessed at nine weeks.

RESULTS: Two hundred and sixty-three patients met the inclusion criteria. At five weeks, there was no difference among the treatment methods with regard to the range of motion or the maintenance of fracture reduction. At nine weeks, there was no significant difference with regard to the range of motion or grip strength.

CONCLUSIONS: When immobilization was discontinued by five weeks, the position of the metacarpophalangeal joints and the absence or presence of interphalangeal joint motion during the immobilization had little effect on motion, grip strength, or fracture alignment. This finding contradicts the conventional teaching that the metacarpophalangeal joint must be immobilized in flexion to prevent long-term loss of joint extension. Patient comfort, ease of application, and the surgeon's familiarity with the technique should influence the choice of immobilization.

LEVEL OF EVIDENCE: Therapeutic Level III.