Postoperative change in patellofemoral alignment following closing-wedge distal femoral osteotomy performed for valgus osteoarthritic knees

Yusuke Akaoka,Ryo Kanto,Keiji Tensho,Hiroshi Nakayama,Tomoya Iseki,Shinichi Yoshiya

doi:10.1186/s43019-020-00035-6

Yusuke Akaoka, Ryo Kanto + Show 4 more

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https://doi.org/10.1186/s43019-020-00035-6

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Abstract

PurposeTo evaluate the postoperative change in patellar position after medial closed distal femoral osteotomy (DFO) performed for valgus osteoarthritic knees.MethodsThe study included 21 consecutive knees in 20 patients undergoing DFO. A minimum of 2-year follow-up data was obtained for all subjects with a mean follow-up period of 42 months (range 31–59 months). The patellar position was evaluated on plain radiographs preoperatively, 1-year postoperatively, and 2-year postoperatively. For patellar height, the modified Insall–Salvati Index (mISI), modified Caton–Deschamps Index (mCDI) and modified Blackburne–Peel Index (mBPI) were measured on the standing lateral radiographs. Patellofemoral alignment on the axial plane was assessed on skyline views with 30° flexion based on the measurements for lateral patellar tilt (LPT) and lateral patellar shift (LPS). Measured values at pre- and postoperative phases were statistically compared using a two-way analysis of variance.ResultsAll indices including mISI, mCDI, mBPI, LPT and LPS showed no statistically significant postoperative changes.ConclusionMedial closed-wedge DFO performed for valgus osteoarthritic knees did not significantly influence patellofemoral alignment either on the sagittal or axial plane. Therefore, to highlight the clinical relevance of our findings, medial closed-wedge DFO for the valgus knee does not adversely affect the patellofemoral joint.Level of evidenceLevel IV, case series.

Highlights

Osteotomy around the knee is adopted as a primary surgical option for knees with unicompartmental osteoarthritis in patients with high activity levels
There have been reports that describe its effects on the patellofemoral joint as a result of patella baja and arthritis [4,5,6,7,8,9,10]
The pre- and postoperative radiological parameters measured for coronal alignment of the lower extremity were as follows: mechanical lateral distal femoral angle (mLDFA), from 84.3 ± 2.0° to 89.3 ± 1.8° with significant postoperative increase (P < 0.001); mechanical tibiofemoral angle (mTFA), from 4.4 ± 4.7° valgus to 0.2 ± 4.7° varus with significant postoperative change (P < 0.001) (Table 2)

Summary

Introduction

Osteotomy around the knee is adopted as a primary surgical option for knees with unicompartmental osteoarthritis in patients with high activity levels. Medial opening-wedge high tibial osteotomy has been widely used for knees with varus deformity, and good treatment outcomes have been reported in the literature [1,2,3]. There have been reports that describe its effects on the patellofemoral joint as a result of patella baja and arthritis [4,5,6,7,8,9,10]. For lateral osteoarthritis in young patients or highly active patients with valgus deformity, the cause of the deformity is often located at the distal end of the femur and in the valgus position.

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