Single Cut Distal Femoral Varus Osteotomy (SCFO): A Preliminary Study

Abstract

Background: Genu valgum usually originates from a deformity of distal femur that is often corrected by distal femoral<br />varus osteotomy. The osteotomy includes both components of angulationcorrection and translation because the site<br />of osteotomy is not commonly at the apex of deformity. Improvement of patellar tracking not only depends on valgus<br />correction, but also it may be partially due to centralization of the trochlear groove under the femoral anatomical axis<br />(FAA).<br />We asked whether we could accurately correct the deformities based on our preoperative goals for the correction of<br />the mechanical axis and centralization of the trochlear groove under the FAA by using a single bone cut.<br />This study describes a new lateral single cut distal femoral osteotomy (SCFO) that enables concurrent correction of<br />angulation and translation.<br />Methods: This study was done on 12 young adult patients with femoral juxta-articular genu valgum deformity<br />using SCFO. The average age at operation was 21 years (range: 16-25). SCFO is a type of closing-opening<br />distal femoral osteotomy that corrects the valgus deformity of the distal femur while the translation of the distal<br />fragment is done using one oblique cut. It centralizes the trochlear groove under the FAA. We compared the pre<br />and postoperative radiographic and clinical variables including mechanical tibiofemoral angle, knee range of motion<br />(ROM), International knee documentation committee (IKDC) score and the time to union. Mean follow-up of the<br />patients was 24 months.<br />Results: The average mechanical tibiofemoral angle improved from 16 degrees (10-23) to 1 degrees (-2 to +2). IKDC<br />subjective score slightly improved from preoperative (65) to 2-year follow-up (71). Centralization of the trochlea was<br />achieved in all patients.<br />Conclusion: SCFO can be a reasonable alternative for correction of the distal femur genu valgum deformity. It can<br />centralize the patellar groove under the FAA with satisfactory clinical outcomes.