The short external rotators dissection during the posterior approach in total hip arthroplasty did not change the blood flow.

Objectives: The posterior approach in total hip arthroplasty (THA) often requires dissection of the short external rotators (SERs), which could increase the postoperative dislocation rate. The reattachment of the dissected SERs has been reported to reduce the dislocation rate, while such repair generally causes progression of muscle atrophy. 1 of the suggested causes of atrophy is reduced blood flow to the repaired SERs. The present study aimed to measure the blood flow of the SERs before dissection (pre-tenotomy) and after reattachment (post-reattachment) during the posterior approach in THA.

Methods: This prospective study included 26 patients who underwent THA via the posterior approach. A laser-Doppler rheometer was used to measure the blood flow in the following SERs at the time of pre-tenotomy and post-reattachment: the piriformis muscle (PM), superior gemellus (SG), inferior gemellus (IG), obturator internus (OI), and subcutaneous tissue as a control.

Results: The average pre-tenotomy and post-reattachment blood flows (mL/minutes/100 g) were: 1.90 ± 0.28 and 1.92 ± 0.40 in the PM, 1.94 ± 0.20 and 1.99 ± 0.39 in the SG, 1.91 ± 0.21 and 1.94 ± 0.30 in the IG, 1.93 ± 0.22 and 1.98 ± 0.36 in the OI, and 1.94 ± 0.24 and 1.87 ± 0.38 in the subcutaneous tissue. The pre-tenotomy and post-reattachment blood flows did not show significant difference in any muscle.

Conclusions: Laser-Doppler blood flow measurements showed that the blood flow is preserved, even when the SERs are dissected and reattached in THA via the posterior approach.