Comparative outcomes of Kirschner wire and lag screw fixation in pediatric medial malleolar fractures.

backgroundSalter-Harris type III and IV medial malleolar fractures (McFarland fractures) are uncommon but clinically significant injuries in skeletally immature patients, with a substantial risk of premature physeal closure (PPC) and subsequent growth disturbance. Various fixation methods, including Kirschner wires (K-wires) and cannulated screws, are used in clinical practice; however, comparative data on their outcomes in pediatric medial malleolar fractures are limited.

methodsThis retrospective study included 60 patients (38 males, 22 females; mean age 11.57 ± 1.78 years) with Salter-Harris type III or IV medial malleolar fractures treated surgically between 2013 and 2023. Patients were categorized according to the fixation method as Kirschner wire fixation (KWF; n = 26) or lag screw fixation (LSF; n = 34). Radiological outcomes included PPC, residual displacement, and lateral distal tibial angle (LDTA). Clinical outcomes at mid-term follow-up (mean 85.37 ± 37.25 months) comprised ankle range of motion (ROM), pain on the Visual Analogue Scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score, Foot and Ankle Outcome Score (FAOS), and complications.

resultsBaseline characteristics were comparable between groups. Open reduction was performed more frequently in the KWF group (80.8% vs. 55.9%; p = 0.043). PPC occurred in 6 patients (23.1%) in the KWF group and 2 patients (5.9%) in the LSF group, representing a non-significant trend toward a higher PPC rate in the KWF group (p = 0.067). Initial LDTA was similar between groups, whereas final LDTA was higher in the KWF group (93.08 ± 6.60° vs. 90.76 ± 5.05°; p = 0.035) and ΔLDTA was greater in the KWF group (3.65 ± 6.29° vs. 1.62 ± 4.95°; p = 0.027). Clinical outcomes (AOFAS, FAOS, VAS, ROM) did not differ significantly between groups. Implant irritation was more frequent after screw fixation, often leading to elective implant removal.

conclusionBoth K-wire and lag screw fixation achieved reliable union and excellent mid-term clinical outcomes in pediatric medial malleolar physeal fractures. Screw fixation was associated with significantly more favorable radiographic alignment (lower final LDTA and smaller ΔLDTA) and a numerically lower PPC rate that did not reach statistical significance. Despite these radiographic differences, functional outcomes were similarly excellent, supporting both techniques as viable options when anatomic reduction is achieved. LEVEL OF EVIDENCE: Level III, retrospective comparative study.