Physical activity following primary total knee arthroplasty for osteoarthritis – a case control study

Introduction: Primary total knee arthroplasty (TKA) is an effective surgical procedure for relieving pain in patients with end-stage osteoarthritis, also offering the opportunity to regain functional ability. Although widely investigated, postoperative physical activity status remains unecertain. Objectives: This study aimed to compare physical activity in patients following primary TKA for osteoarthritis and those still not proposed the surgical intervention, suffering from knee osteoarthritis. Material and methods: We conducted a pilot study to find important covariates and biases for the study followed by a retrospective study on a series of 21 randomized cases and 30 controls. Cases were patients who underwent primary TKA for osteoarthritis at our Hospital between 2007 and 2011 (mean age 63) and the control group included patients suffering from knee osteoarthritis, not submitted to THA (mean age 60), from a Primary Care Institution database search. Patients completed Knee Osteoarthritis Outcome Score (KOOS) and International Physical Activity Questionnaire (IPAQ) by telephone interviews, by a single observer. Mann-Whitnney test was used to compare case and control groups, regarding IPAQ and KOOS. We found no statistically significant difference between groups in each questionnaire parameters, except for Symptoms in KOOS (p<,05). vigorous activity was absent in both groups. We could not exclude the null hypothesis correlation with age, by spearman's test. Discussion: Patient-reported outcomes are measures in which the patient provides an evaluation of his health condition or treatment from his perspective. This minimizes observer bias and informs about factors that are likely to be important to the patient. There is considerable overlap in levels of pain and dysfunction between those who are and are not recommended for THA in clinical practice, which may explain the absence of statistically significant difference between case and control groups in the majority of variables in IPAQ and KOOS in his study. Moreover, according to some studies, patients have higher expectations than their surgeon regarding high-level activities and extreme range of motion following arthroplasty, which was indeed not observed in our case group. TKA seems however important in relieving symptoms in patients undergoing the procedure. Conclusions: Patients with TKA present less symptoms than those suffering from osteoarthtitis no submitted to surgery, but are similar regarding activity, sports and quality of life. Special attention should be given to patient's expectations regarding physical activity following this procedure