To explore the posterior-superior retinacular artery preservation in the quadratus femoris-bone flap grafting for the treatment of femoral head necrosis.

Modified quadratus femoris bone flap with posterior-superior retinacular artery was designed and anatomic study was carried out in four chilled specimens. A retrospective analysis was performed on 25 male patients, age from 20 to 50 years, who received hip preservation treatment for femoral head necrosis in 920th Hospital of Joint Logistics Support Force of PLA from January 2019 to March 2021. According to Association Research Circulation Osseous(ARCO)classification, thirteen hips were in stage II and 12 hips in stage III. All the patients received preoperative digital subtraction angiography (DSA) for posterior-superior retinacular artery and were treated by hip-preservation surgery with quadratus femoris bone flap retaining retinacular artery. The patients with acute infections, taking steroids for other diseases, severe cardiocerebral vascular diseases and coagulation disorders were exluded. In the postoperative 12^th month, hip function was assessed using Harris score, international hip outcome tool (iHOT-12), and visual analogue scale(VAS). Paired t test was performed for data analysis.

All the four specimens were completed the surgical design successfully and retained the posterior superior retinacular artery completely. The posterior superior retinacular arteries of the femoral heads in six hips (75%) were derived from the medial circumflex femoral artery, those of two hips (25%) were derived from the inferior gluteal artery and the average length of bone flap was (4.0±0.1) cm. All 25 patients were followed up for (13.2±0.8) months on average. The Harris score of hip joint increased from (56.92±0.89) points before surgery to (91.92±0.55) points after surgery (t=33.48, P<0.05), iHOT-12 score increased from (60.40±1.05) points before surgery to (107.00±0.63) points after surgery (t=37.88, P<0.05), VAS decreased from (6.36±0.16) points before surgery to (1.92±0.14) points after surgery (t=20.70, P<0.05). Complete posterior superior retinacular artery was developed in 96% of the patients. No further necrosis of femoral head occured during the follow-up.

Modified quadratus femoris bone flap can effectively preserve the blood supply of the femoral head, providing a new method for hip preservation, but long-term follow-up is needed to further evaluate its therapeutic effect.