Publication:

Risk factors for a post-operative neutrally aligned total knee arthroplasty in the sagittal plane developing fixed flexion deformity at 2 years follow up study

Background The incidence of fixed flexion deformity (FFD) following total knee arthroplasty (TKA) has been reported to be as high as 17%, increasing demand on the quadriceps and hindering mobility. The aim of this study is then to identify these predictors for the development of FFD.

Methods In this retrospective study, all patients who underwent primary TKA from January 2008 to June 2009 at a single institution were identified. All patients with neutral alignment in the sagittal place of the knee intra-operatively were identified and followed up. The knee motion was measured in both operated and contralateral knees and followed-up for a minimum of 24 months post-operatively.

Results Multivariate analysis demonstrated pre-operative FFD of the non-operated knee (p-value 0.03), pre-operative range of motion of the operated knee (p-value 0.01) and non-operated (p-value 0.01) knee and pre-operative maximum flexion of the operated knee (p-value 0.001) to be independent risk factors for development of FFD at 24 months.

Conclusions Independent risk factors for the development of post-operative FFD in TKA are pre-operative FFD of the operated knee, FFD of the non-operated knee and the maximum flexion of the operated knee. The relative risk of a male developing FFD is also as high as 1.34.