The effect of changing femoral offset and abductor stretching exercises on abductor muscle activation after total hip arthroplasty?

The aim of this study is to examine the effects of abductor stretching exercises added to the conventional rehabilitation program on abductor muscle activation and frontal plane pelvic asymmetry in individuals who underwent total hip arthroplasty (THA). Participants who met the inclusion criteria were randomized into two groups: the treatment group (n=15), which received stretching, and the control group (n=13), which did not receive stretching. Participants in the treatment group received abductor stretching exercises in addition to the conventional physiotherapy program, while participants in the control group received the conventional physiotherapy program twice a week for six weeks. Participants were evaluated before surgery and six weeks after surgery. Muscle activation was assessed with surface EMG, muscle strength with a hand dynamometer, pelvic asymmetry with a standing pelvic AP X-ray, leg length with a tape measure, and pain intensity with a numeric pain scale. Additionally, single-leg stance duration and the 30-second sit-to-stand test were evaluated. The Oxford hip score was used to assess functionality. According to the results of the study, a statistically significant difference was found in the gluteus medius and gluteus maximus muscle activation during the 2-minute walking test in the treatment group at the 6-week evaluation compared to the control group (p<0.05). However, no statistically significant difference was observed between the two groups in the Oxford hip score, pain intensity, sit-to-stand repetitions, single-leg stance duration, pelvic asymmetry, leg length measurement, offset measurement, and muscle strength evaluation (p>0.05). Nevertheless, abductor stretching exercises (targeting gluteus medius and tensor fascia lata) added to progressive strengthening exercises after THA increased abductor muscle activation measured by surface EMG. In addition, the abductor muscle strength evaluated by the dynamometer increased significantly in the treatment group after therapy (p<0.05). We concluded that abductor stretching exercises could be beneficial to facilitate and optimize sufficient muscle activation after THA. Therefore, stretching exercises added to strengthening exercises for hip abductors can be incorporated into rehabilitation programs