Functions, disabilities and perceived health in the first year after total knee arthroplasty; a prospective cohort study.

Background: In end-stage knee osteoarthritis total knee arthroplasty (TKA) is an effective intervention to reduce pain and improve functioning in the majority of patients. However, after TKA some patients still experience pain, loss of function, deficient muscle strength or reduced walking speed. This study systematically assesses patients' functions, disabilities and health before TKA and at short- (3 months) and long-term (12 months) on all International Classification of Functioning, Disability and Health domains.

Methods: In this prospective cohort study 150 patients underwent the following tests before and at 3 and 12 months after surgery: Western Ontario and McMaster Universities Arthritis Index, Short Form 12, Knee Society Score, Patient Specific Functioning Scale, knee range of motion, quadriceps and hamstring strength, gait parameters, global perceived effect (only after surgery). All data was analyzed with repeated measures ANOVA for all measurement time points.

Results: Despite increased gait speed, quadriceps strength and scores on questionnaires being above pre surgical levels, patients do not reach levels of healthy persons. Walking speeds approach normal values and are higher in our study compared with the literature. Quadriceps strength stays at around 70 till 80% of norm values. However, dissatisfaction rates are below 10%, which is low compared to the literature.

Conclusions: Quality of life, activities, muscle strength and gait parameters improve significantly after TKA. However, some complaints regarding activities and walking speed remain. Most striking outcome is the remaining deficit in quadriceps strength.