A safe technique in performing gluteus maximus tenotomy in the Kocher-Langenbeck approach.

Background: Gluteus maximus (GMax) tenotomy is a well described technique to improve femoral and/or acetabular exposure during the Kocher Langenbeck approach. Branches of the first femoral perforator artery (1FPA) are frequently encountered and may be injured during the tenotomy, causing bleeding and obscuration of surgical field. The understanding of vascular anatomy around GMax insertion is poor. This study aims to identify the origin, size, course, and consistency of these vessels, and a safe technique for GMax tenotomy.

Methods: 100 eligible computed-tomography angiograms (CTA) of the lower-limbs were identified between January 2019 and July 2021 with 200 limbs studied. The gluteal tuberosity (GTu) was set as the origin of GMax tendon insertion. CTAs were reconstructed in multiplanar reformats, including 3D reconstructions. The 1FPA and its branches were mapped, their anatomical course, size, and relationship with GTu and posterior femoral cortex were recorded.

Results: Average age of cohort was 66.5years. Out of 200 limbs, 2 anatomical arterial variants of the 1FPA were identified near the gluteal tubercle. 23 limbs (11.5%) had a proximal (high) take-off of the 1FPA. 177 (88.5%) had a long ascending vessel originating from the 1FPA. The courses of both arteries are consistent. The average luminal size of these vessels was 2.1 mm. In terms of vertical distance, 12 (6%) limbs had an artery within 15 mm from the GTu, the assumed top of GMax tendon insertion. All 200 vessels were seen within 10 mm of the posterior cortex. The combination of these findings make up the "safe-zone" of GMax tenotomy.

Conclusions: This is the first to detail the origin, course, and size of the ascending artery in relation to GMax tendon. The "Safe zone" of GMax tenotomy is a 15-mm partial release, at least 10 mm off the posterior femoral cortex.