The Influence of Implant Position on Final Clinical Outcome and Gait Analysis after Total Knee Arthroplasty.

The aim of the study was to evaluate the impact of implant component alignment on objective and subjective outcomes after total knee arthroplasty (TKA). The rotation of the femoral component and its influence on the final results were also examined. After exclusion, the study examined 102 patients (mean age, 66.28 years; range, 51-79 years) who had undergone unilateral TKA. All of the operative procedures were performed by one surgeon with one type of implant. One year after the operation, improvements in Knee Society's Knee Scoring System, functional score, Western Ontario and McMaster Universities Osteoarthritis Index, and Visual Analog Scale were observed; however, none showed a significant correlation with any of the parameters analyzed by X-ray or computed tomography (CT) (α, β, γ, δ angles and posterior condylar angle [PCA]). Significant improvements were found for the vast majority of the parameters used for gate analysis at the final follow-up. Significant correlations were found between PCA angle and differences in stance phase, swing phase of the operated limb, and step width (all p  = 0.03). No other significant relationships were found between gait parameters and indicators measured by X-ray and CT. None of the analyzed radiographic parameters, including rotation of the femoral component, correlated with final clinical results. Neither femoral internal rotation of 3° to 6°, nor rotation of 0° ± 3° or 0° ± 6° influenced the outcome. One year after TKA, a significant improvement was observed in both functional and gait parameters.