[Direct anterior craniocervical junction fenestration decompression and bone graft for the treatment of early and middle stage osteonecrosis of the femoral head: a 3-year follow-up].

Objective: To assess the mid-term clinical efficacy of the direct anterior approach for window decompression and bone grafting surgery in the treatment of early to mid-stage osteonecrosis of the femoral head (ONFH).

Methods: A retrospective analysis was performed on 40 patients (40 hips) diagnosed with osteonecrosis of the femoral head (ONFH), classified as types L1 and L2 according to the China-Japan Friendship Hospital (CJFH) classification system, and at stagesⅡ, ⅢA, and ⅢB based on the Association Research Circulation Osseous (ARCO) staging system. All patients underwent head-neck junction fenestration decompression and bone grafting via the direct anterior approach between January 2015 and May 2022, with complete follow-up data available for a minimum of three years. The ages of the patients ranged from 35 to 69 years old, with a mean of (49.13±6.14 ) years old;their body mass index (BMI) ranged from 20.02 to 27.94 kg·m^-2, with a mean of (23.65±1.69) kg·m^-1;the duration of the disease ranged from 13 to 36 months, with a mean of (24.55±4.14) months. Preoperative and 3-year postoperative X-ray parameters were collected, including the anterior preserved angle(APA), lateral preserved angle (LPA), and combined preserved angle (CPA). Additionally, hip joint disability and osteoarthritis outcome scores (HOOS) and Harris hip scores (HHS) were recorded.

Results: Forty patients were followed up for a period ranging from 36 to 59 months, with a mean duration of (47.18±6.18) months. At 3 years postoperative, none of the patients underwent hip replacement surgery. The APA (73.15±19.35)°, LPA (75.35 ±21.48)°, and CPA (136.25±26.78)° at the 3-year postoperative significantly improved compared to preoperative measurements (61.93±20.54)°, (59.46±22.67)°, and (116.58±32.47)°, with statistical significance (P<0.05). The HOOS (20.37±1.39) and HHS (89.74±3.28) scores at the 3-year postoperative were significantly improved from preoperative scores (12.36±1.58) and (50.27±6.15), respectively, with statistical significance (P<0.05).

Conclusion: The direct anterior approach for window decompression and bone grafting surgery can relieve joint pain, improve joint function, and enhance X-ray preserved angles, effectively preventing femoral head collapse, making it an effective surgical method for treating ONFH classified as L1, L2 according to CJFH and stagesⅡ, ⅢA, ⅢB according to ARCO.