In Silico Comparison of Two Kirschner Wire Arrangements for Stabilization of Femoral Capital Physeal Fractures †

Despite advancements in surgical techniques, including the utilization of intra-operative fluoroscopy and custom surgical guides, intra-articular implant placement during the pinning of capital physeal fractures can occur and may result in catastrophic complications. Our objective in this study was to compare the epiphyseal purchase afforded by a linear and triangular pattern of Kirschner wires for stabilizing femoral capital physeal fractures. Archived pelvic limb computed tomography scans of 16 skeletally immature dogs were obtained, from which virtual femoral models were created. Separate linear and triangular arrangements of three virtual 1.6 mm Kirschner wires were centered on the thickest region of the proximal epiphysis. The length of each Kirschner wire implanted within the proximal femoral epiphysis was measured. Kirschner wire placement in triangular and linear patterns resulted in a mean epiphyseal purchase for each wire of 8.4 mm and 8.0 mm, respectively. The cumulative Kirschner wire purchase was greater with the triangular pattern (p = 0.004). The mean difference in the cumulative wire purchase was 1.3 mm. The use of a triangular Kirschner wire pattern resulted in greater implant purchase within the epiphysis compared to the linear pattern. The triangular Kirschner wire pattern may reduce the risk of intra-articular implant placement by more closely centering the wires within the thickest region of the epiphysis.