Analysis of the relationship between the morphology of the proximal tibiofibular joint and lateral hinge fracture in open wedge high tibial osteotomy.

Background: One of the complications of open wedge high tibial osteotomy is lateral hinge fracture, which causes delayed bone healing. In this study, we focused on the morphology of the proximal tibiofibular joint to clarify the influence of this morphology on the occurrence of lateral hinge fracture in open wedge high tibial osteotomy.

Methods: The proximal tibiofibular joint of 58 knees in 55 patients who underwent open wedge high tibial osteotomy was classified as either horizontal or oblique, depending on the morphology of the fibular head. Lateral hinge fracture of Takeuchi classification type II or III was defined as unstable lateral hinge fracture. We analyzed whether patient background and bone morphological factors, including the morphology of the proximal tibiofibular joint, were associated with the occurrence of unstable lateral hinge fracture.

Results: The horizontal and oblique types were found in 34 and 24 knees, respectively. There was no difference in the percentage of hinge points within the safe zone between the horizontal and oblique types; however, there was a significant difference in the unstable lateral hinge fracture incidence between the two groups. Unstable lateral hinge fracture occurred in seven knees, mostly in patients with an oblique proximal tibiofibular joint. The factors associated with the occurrence of unstable lateral hinge fracture were analyzed using logistic regression analysis; the fibular head of the oblique type was a significant factor.

Conclusion: Open wedge high tibial osteotomy for oblique-type proximal tibiofibular joints may be more likely to cause unstable lateral hinge fracture than the horizontal type.