Antegrade intramedullary pinning versus retrograde intramedullary pinning for displaced fifth metacarpal neck fractures.

Abstract

Severe angulation or shortening can be a surgical indication for fifth metacarpal neck fracture. In a previous meta-analysis, antegrade intramedullary pinning was shown to produce better hand function outcomes than percutaneous transverse pinning or miniplate fixation for treatment of fifth metacarpal neck fractures. However, the outcomes of retrograde intramedullary pinning, to our knowledge, have not been compared with those of antegrade intramedullary pinning. We asked whether the clinical and radiographic outcomes of antegrade intramedullary pinning are different from those of percutaneous retrograde intramedullary pinning for treating patients with displaced fifth metacarpal neck fractures. Forty-six patients with displaced fifth metacarpal neck fractures with an apex dorsal angulation greater than 30° were enrolled in our prospective study. Subjects were treated randomly by antegrade intramedullary pinning (antegrade group) or by percutaneous retrograde intramedullary pinning (retrograde group). Clinical evaluations, which included active ROM of the fifth metacarpophalangeal joint, VAS for pain, grip strength, and DASH score, were performed at 3 months and 6 months postoperatively. Radiographic evaluations of apex dorsal angulation and axial shortening were performed preoperatively and 6 months postoperatively. Patients in the antegrade group achieved better outcomes than patients in the retrograde group for all clinical parameters at 3 months postoperatively (ROM: antegrade median 80° [range, 57°-90°] versus retrograde 69° [range, 45°-90°], difference of medians 11°, p < 0.001; VAS: antegrade median of 2 [range, 0-5] versus retrograde 4 [range, 0-7], difference of medians 2, p < 0.001; grip strength: antegrade median 81% [range, 60%-100%] versus retrograde 71% [range, 49%-98%], differences of medians 10%, p < 0.001; DASH: antegrade median 4.3 [range, 0-15.8] versus retrograde 10.3 [range, 0-28.4], difference of medians 6, p < 0.001), but these differences, with the numbers available, were not observed at 6 months postoperatively for any clinical parameters (ROM: antegrade median 88° [range, 81°-90°] versus retrograde 87° [range, 80°-90°], difference of medians 1°, p = 0.35; VAS: antegrade median 1 [range, 0-2] versus retrograde 1[range, 0-3], difference of medians 0, p = 0.67; grip strength: antegrade median 93% [range, 78%-104%] versus retrograde 91% [range, 76%-101%], difference of medians 2%, p = 0.41; DASH: antegrade median 3 [range, 0-12.5] versus retrograde of 4.3 [range, 0-15.8], difference of medians 1.3, p = 0.48). At 6 months postoperatively, there also were no differences, with the numbers available, in radiographic parameters between the antegrade and retrograde fixation groups. Residual angulation was not different (antegrade median: 7° [range, 2°-11°], retrograde: 9° [range, 3°-13°], difference of medians 2°, p = 0.56). Shortening between the two groups also was not different (antegrade median: 1 mm [range, 0 mm-2 mm], retrograde median: 1 mm [range, 0 mm-2 mm], difference of medians 0, p = 0.78). Our study findings suggest antegrade intramedullary pinning has some clinical advantages during the early recovery period over percutaneous retrograde intramedullary pinning for treatment of displaced fifth metacarpal neck fractures, but the advantages are not evident at 6 months postoperatively. In addition, our study showed no differences in radiographic outcomes between antegrade and retrograde techniques. For patients who require an early return of hand function, such as athletes, antegrade intramedullary pinning can be recommended. Otherwise, treatment could be decided according to the surgeon's preference and patient status, and based on consideration of the need for an accessory procedure for pin removal after antegrade intramedullary pinning. Level I, therapeutic study.