Acta Kinesiologiae Universitatis Tartuensis. 2011, Vol. 17 GAIT AND MUSCLE STRENGTH CHARACTERISTICS IN TOTAL KNEE ARTHROPLASTY PATIENTS WITH PATELLOFEMORAL PAIN SYNDROME BEFORE AND SIX MONTHS AFTER SURGERY H. Gapeyeva 1,2 , J. Ereline 1,2 , T. Haviko 3 , H. Aibast 1,2 , M. Pääsuke 1,2 1 Institute of Exercise Biology and Physiotherapy, University of Tartu, Tartu, Estonia 2 Centre of Behavioural and Health Sciences, University of Tartu, Tartu, Estonia 3 Department of Traumatology and Orthopaedics, University of Tartu, Tartu, Estonia ABSTRACT The aim of the present study was to investigate the gait and muscle strength characteristics in total knee arthroplasty (TKA) patients with patellofemoral pain syndrome (PFPS) before and six months after surgery. Eight patients (4 men and 4 women) aged 58–77 years with PFPS following unilateral TKA who had primary degenerative knee OA participated in the study before and six months after reoperation. In patients was registered the active range of motion (AROM) of knee extension and flexion, hip abduction and adduction. Isometric maxi- mal voluntary contraction (IMVC) force of knee flexors, extensors, abductors and adductors was measured and gait kinematic characte- ristics and kinetic characteristics of knee joint were recorded. Knee flexion AROM in the involved leg was significantly lower (p<0.05) as compared to the uninvolved leg pre- and post-surgery. The patients had greater (p<0.05) hip abduction AROM and significant increase (31%, p<0.05) of IMVC force of the involved legʼs hip abductors postoperatively as compared before surgery. Six months after surgery