Minimally invasive treatment for osteonecrosis of the femoral head with angioconductive bioceramic rod.

PURPOSE: To describe the rationale, the surgical technique, and the short-term follow-up results of a new minimally invasive treatment of osteonecrosis of the femoral head (ONFH) with an angioconductive bioceramic rod (ABR) implant. METHODS: Sixty-two patients (72 hips) with ARCO stage IIA-IIIC ONFH treated with the minimally invasive ABR from January 2012 to December 2016 were reviewed (17 females, 45 males, mean age 44.49). This technique used the angioconductive properties of the porous implant to repair the necrosis by driving vascularization from the trochanter to the necrotic area. Patients had a mean follow-up period of 26.74 months. The outcomes were evaluated by hip joint survival, radiograph, and the Harris Hip Score (HHS). The complications occurred during the treatment period were recorded. RESULTS: No serious post-operative complications occurred during the treatment. The overall joint survival rate was 90.27%, with seven conversions to THA. Improvements were observed in 23 (31.95%) hips, 24 (33.33%) hips remained stable, and 25 (34.72%) hips had worse results according to the radiographic evaluation. The mean HHS at the end follow-up significantly improved compared to the pre-operative mean HHS (82.27 vs 58.14, p < 0.001). In both radiographic evaluation and HHS, the treatment was more effective on patients beneath 44 years old (p < 0.05); ARCO stage II compared to stage III (p < 0.05); and China-Japan Friendship Hospital (CJFH) type C compared to CJFH type L (p < 0.05). CONCLUSIONS: The minimally invasive treatment of ONFH with ABR showed promising results in delaying or even terminating the progression of the necrosis and improving hip function, especially in younger patients and in the early stages of the disease.

[Minimally invasive treatment for osteonecrosis of the femoral head in ARCO stage â ¡ and â ¢ with bioceramic system].

OBJECTIVE: To perfect the theory system of minimally invasive treatment for osteonecrosis of the femoral head (ONFH) with ß tricalcium phosphate (ß-TCP) bioceramic system and evaluate the effectiveness. METHODS: Eighteen New Zealand white rabbits aged 7-8 months were used to establish an animal model to verify the vascularization of porous ß-TCP bioceramic rods. Micro-CT based three-dimensional reconstruction and fluorescence imaging were used to display the new blood vessels at 4, 8, and 12 weeks after operation. The inserting depth, number and diameter of vessels in the encapsulated area were analyzed. Nine pig femoral specimens were randomly divided into 3 groups ( n=3): group A was normal femur; group B had cavity (core decompression channel+spherical bone defect in femoral head); in group C, mixed bioceramic granules were implanted to fill the defect in femoral head, and porous ß-TCP bioceramic rod was implanted into decompression channel. The stiffness and yield load of specimens were analyzed by biomechanical test. A multicenter retrospective study was conducted to analyze 200 patients (232 hips) with femoral head necrosis treated with bioceramic system in 7 hospitals in China between January 2012 and July 2018. There were 145 males and 55 females, with an average age of 42 years (range, 17-76 years). According to the Association Research Circulation Osseous (ARCO) stage, 150 hips were in stage Ⅱ and 82 hips in stage Ⅲ. Postoperative imaging assessment was carried out regularly, and hip function was evaluated by Harris score. The effectiveness of ARCO stage Ⅱ and Ⅲ was also compared. RESULTS: Animal experiments showed that blood vessels could grow into the encapsulated area and penetrate it at 12 weeks. The inserting depth, number and diameter of blood vessels in the encapsulated area gradually increased, and there was significant difference between different time points ( P<0.05). Biomechanical tests showed that the stiffness and yield load of specimens in groups B and C were significantly lower than those in group A, while the yield load in group B were significantly lower than that in group C ( P<0.05). The stiffness in group C was restored to 41.52%±3.96% in group A, and the yield load was restored to 46.14%±7.85%. Clinical study showed that 200 patients were followed up 6-73 months, with an average of 22.7 months. At last follow-up, 12 patients (16 hips) underwent total hip arthroplasty, and the hip survival rate was 93.10%. According to the imaging evaluation, 184 hips (79.31%) were stable and 48 (20.69%) were worse. Harris score (79.3±17.3) was significantly higher than that before operation (57.3±12.0) ( t=18.600, P=0.000). The excellent rate of hip function was 64.22% (149/232). The survival rate of hip joint, imaging score and Harris score of patients in ARCO stage Ⅱ were better than those in ARCO stage Ⅲ ( P<0.05). CONCLUSION: ß-TCP bioceramic system can guide the abundant blood supply of greater trochanter and femoral neck to the femoral head to promote repair; it can partly restore the mechanical properties of the femoral head and neck in the early stage, providing a new minimally invasive hip-preserving method for patients with ONFH, especially for those in early stage.