Radiographic assessment of metacarpal shortening after nonoperative and operative treatment of spiral and oblique metacarpal shaft fractures.

BACKGROUND AND PURPOSE: Spiral or oblique metacarpal shaft fractures (MSFs) can be treated nonoperatively with unrestricted mobilisation; however, this approach leads to bone shortening upon healing. While an association between bone shortening and impaired hand function is suspected, empirical clinical evidence is lacking, and differing measurement methods make comparisons between studies difficult.

METHODS

This study is based on a midterm follow-up (mean 4.5 years) of 33 patients with a single spiral or oblique MSF from our previous randomised controlled trial. The original study and the present study were registered at clinicaltrials.gov (NCT03067454, NCT05869331). The main outcome in the present study was the amount of shortening following nonoperative compared with operative treatment. Bilateral radiographs were obtained, and shortening was determined by comparing the fractured metacarpal to its contralateral counterpart using the Shortening Absolute (SH-Abs) measurement method. Intra- and interrater reliability for SH-Abs were presented with intraclass correlation coefficients. Additional outcomes included extension deficit, cosmesis, and overall satisfaction.

RESULTS

17 patients had been treated nonoperatively with unrestricted mobilisation and 16 operatively. Mean shortening was 3.9 mm (95% confidence interval [CI], 4.8-3.0 mm) and 0.9 mm (95% CI, 2.0 to -0.3 mm), respectively, with a mean difference of 3 mm (95% CI, 4.3-1.6 mm) (p < 0.001). The SH-Abs showed substantial to excellent reliability. Extension deficit, cosmesis, and overall satisfaction were similar in both groups.

CONCLUSIONS

Metacarpal shortening is to be expected after nonoperative treatment of displaced spiral or oblique MSFs. SH-Abs provides a reproducible measurement and could be used to facilitate comparisons between studies.