Isokinetic performance and function are similar after total hip arthroplasty applied with a posterior or anterolateral approach: a randomised controlled trial.

BACKGROUND

There are ongoing debates on the effects of surgical approach on outcome after total hip arthroplasty (THA). It was hypothesised that with the anterolateral approach, trauma to the abductor arm can occur and related detrimental effects can diminish the postoperative outcomes. In this first randomised controlled trial in the literature on this subject, isokinetic performance and patient-reported functional outcomes were evaluated in patients undergoing THA with a posterior approach (PA) and an anterolateral approach (ALA).

METHODS

A total of 48 patients scheduled to undergo THA were randomised to ALA or PA groups. The patients were evaluated preoperatively and at 6 and 12 months postoperatively, with flexion, extension and abduction strength measurements and the Harris Hip Score (HHS). The physiatrist performing isokinetic tests and the patients were blinded to the study groups.

RESULTS

Both groups were similar in respect of age, body mass index (BMI), gender and preoperative isokinetic performance and HHS. Both groups demonstrated similar isokinetic performance ( < 0.05) and there was no difference in HHS ( < 0.05) at the 6- and 12-months follow-up evaluations.

CONCLUSION

Although there is concern about potential abductor muscle damaging during ALA, the results of this randomised controlled study demonstrated that ALA can produce similar isokinetic performance and functional outcome to PA at 6 and 12 months, despite the close proximity to the abductor arm.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT04640740 (retrospectively registered).