Quality of Life, Outcome Scores, and Prognostic Factors of Persistent Fixed Flexion Deformity at Six Months after Total Knee Arthroplasty

Abstract

This study examined quality of life (SF-36), Clinical Knee Society (Function/Knee) score and Oxford Knee score of primary total knee arthroplasty (TKA) patients with persistent fixed flexion deformity (FFD) ≥10° at six months follow-up. Pre-operative and post-operative clinical data of Group 1 (n=95; 0°< FFD<10°), Group 2 (n=39; FFD>10°) and Control (n=209; FFD=0°) were analysed. FFD improvement was maintained in Control and Group 1 at two years while Group 2 demonstrated little change. Flexion decreased at six months before improving at two years post-TKA was noted in all groups. For Control, significant improvements in majority of SF-36's domains except general health were observed. For Groups 1 and 2, significant improvements were observed in SF-36's physical role, physical role functioning, bodily pain, and social role functioning. Vitality improvement was indicated in Group 1 while emotional role functioning was observed in Group 2. Significant improvements in Clinical Knee Society and Oxford Knee scores were also observed in all groups. Multiple regression analysis revealed that pre-operative factors such as gender ( p=0.035) and pre-operative FFD ( p=0.002) were predictors that correlated with FFD improvement. Our results suggested that FFD have significant impact on quality of life and outcome scores and whenever possible, these should be tracked in order to obtain sufficient information for understanding and aiding the recovery of residual FFD patients after TKA.