Correlation between objective gait parameters and subjective score measurements before and after total knee arthroplasty

The absence of uniformity, the use of different terminologies, and the diversity of methods used to translate numerical data into clinical outcomes have been described as potential problems when dealing with clinical knee scores for total knee arthroplasty (TKA). Gait analysis is believed to provide more objective parameters. The aim of the present study was to obtain information about the correlation between the outcome in terms of locomotion and the clinical knee score after TKA.

Thirty consecutive patients awaiting TKA were involved in the study. One day prior to surgery and 3 months postoperatively, data pertaining to the Hospital for Special Surgery Score (HSS) and the Knee Society Score (KSS) (subgroups ‘pain’, ‘knee’, ‘function’ and ‘total sum’) were analyzed for correlations with kinematic and temporospatial parameters of gait analysis.

At a significance-level of p ≤ 0.001 moderate correlations (0.4 <  r < 0.6) were found preoperatively, particularly between ‘max knee flexion swing’ and the function-subscores of HSS and KSS and the ‘KSS total’. High correlations (0.6 <  r < 0.8) were ascertained for ‘stride length’ and ‘gait velocity’ with ‘KSS function’. High correlations were also determined between ‘stride length’ and ‘KSS total’ and between ‘gait velocity’ and ‘HSS function’. The only correlation found postoperatively was between ‘max pelvic obliquity stance’ and ‘KSS knee’ ( r = 0.770, p < 0.001).

We conclude that the ‘function’ subscores of KSS and HSS are highly suitable to assess the functional capacity of patients scheduled for TKA. However, because no adequate correlations between knee scores and gait parameter were found postoperatively, we cannot recommend the abandonment of gait analysis when monitoring the functional benefit of TKA.