The Effect of Early Hip-strengthening on Physical Function in Patients With Unilateral Total Knee Arthroplasty

Abstract

Background and Aim: Conventional post-operative rehabilitation programs focus on quadriceps strengthening and knee range of motion. However, hip muscle weakness is evident in patients with knee osteoarthritis. The present trial study aimed to investigate the effects of adding early hip muscle strengthening exercises to conventional rehabilitation programs on pain, Range of Motion (RoM), Quality of Life (QoL), and physical function in patients with unilateral Total Knee Arthroplasty (TKA). Methods & Materials: The intervention was initiated from the second day after surgery and continued for 10 sessions, 3 times a week on 24 participants in the control and intervention groups. Both research groups received Transcutaneous Electrical Neural Stimulation (TENS) and Infra-Red (IR), followed by exercises. The control group performed knee extensor and flexor strengthening and RoM exercises. The intervention group conducted hip-strengthening exercises in addition. Outcome measures included pain, knee flexion, and extension RoM, and QoL using the 36-Item Short Form Survey (SF-36), Timed Up and Go (TUG) test, Step Test, Six-Minute Walk Test (6MWT), and Hip and Knee Muscle Strength test. Ethical Considerations: This research was approved by the Research Ethics Committee of Iran University of Medical Sciences (IR.IUMS.REC.1396.9511340012) and it was registered in the Clinical Trial Registration Center (Code: IRCT 20150314021459N6). Results: All outcome measures improved in both research groups. The improvement in the scores of pain (P=0.03), knee extension RoM (P=0.007), and TUG test (P=0.033) were significantly higher in the intervention group, compared to the control group. The strength of knee flexors (P=0.023), hip flexors (P=0.040), hip extensors (P=0.028), hip adductors (P=0.040), and hip external rotators (P=0.047) significantly improved higher in the intervention group. Conclusion: According to the present research results, both treatment approaches were effective on patients with unilateral total knee arthroplasty. Considering the better result of some of the outcome measures in the intervention group, the addition of hip strengthening exercises to knee exercises can be useful.