Modified non-transarticular K-wire external fixation versus traditional transarticular pinning for bony mallet finger: a prospective comparative cohort study

BACKGROUND: Traditional transarticular distal interphalangeal joint (DIPJ) pinning for bony mallet fingers risks stiffness and iatrogenic cartilage injury. This study compared a modified non-transarticular K-wire external fixator with traditional transarticular pinning for surgically treated bony mallet finger. METHODS: This single-center prospective nonrandomized comparative cohort study included 120 adults with acute bony mallet finger. Sixty patients underwent traditional transarticular DIPJ pinning, and 60 underwent modified non-transarticular K-wire external fixation. The primary outcome was overall postoperative complications, including pin tract infection, joint stiffness, loss of reduction, nail deformity, or radiographic degenerative change assessed at 1 year. Secondary outcomes included operative time, hardware removal time, bone union time, DIPJ motion, Crawford grade, pain, QuickDASH score, and return-to-work time. Logistic regression was used to identify predictors of overall complications. RESULTS: Baseline demographic and injury characteristics were comparable between groups. Overall complications were significantly less frequent after modified fixation than after traditional fixation (15.0% vs 48.3%, p < 0.001). The modified technique markedly reduced joint stiffness and nail deformity. It was also associated with shorter operative time, earlier hardware removal, faster bone union, lower extension lag, greater maximum DIPJ flexion, better Crawford grade distribution, lower pain and QuickDASH scores, and earlier return to work. In multivariable analysis, traditional fixation remained independently associated with higher complication risk. CONCLUSION: Modified non-transarticular K-wire external fixation was associated with fewer complications and better early functional recovery than traditional transarticular DIPJ pinning. This joint-sparing, low-cost technique may be a useful surgical option for selected patients with bony mallet finger.