Regenerative therapies increase survivorship of avascular necrosis of the femoral head: a systematic review and meta-analysis.

PURPOSE: The aim of this study was to document the available evidence on the use of regenerative techniques for the treatment of femoral head osteonecrosis (or avascular necrosis of femoral head, AVN) and to understand their benefit compared to core decompression (CD) alone in avoiding failure and the need for total hip replacement (THR). METHODS: The search was conducted on three medical electronic databases according to PRISMA guidelines. The studies reporting number and timing of failures were included in a meta-analysis calculating cumulative survivorship with a Kaplan-Mayer curve. Moreover, the results on failures in treatment groups reported in RCT were compared with those documented in control groups, in order to understand the benefit of biological therapies compared to CD for the treatment of AVN. RESULTS: Forty-eight studies were included in this systematic review, reporting results of different types of regenerative techniques: mesenchymal stem cell implantation in the osteonecrotic area, intra-arterial infiltration with mesenchymal stem cells, implantation of bioactive molecules, or platelet-rich plasma. Overall, reported results were good, with a cumulative survivorship of 80% after ten year follow-up, and better results when regenerative treatments were combined to CD compared to CD alone (89.9% vs 70.6%, p < 0.0001). CONCLUSION: Regenerative therapies offer good clinical results for the treatment of AVN. The combination of CD with regenerative techniques provides a significant improvement in terms of survivorship over time compared with CD alone. Further studies are needed to identify the best procedure and the most suitable patients to benefit from regenerative treatments for AVN.

Effects of electrical stimulation in the treatment of osteonecrosis of the femoral head.

INTRODUCTION: The aim of this study was to examine whether the use of an internal electrostimulator could improve the results obtained with core decompression alone in the treatment of osteonecrosis of the femoral head. METHODS: We performed a retrospective study of 41 patients (55 hips) treated for osteonecrosis of the femoral head between 2005 and 2014. Mean follow-up time was 56 (12-108) months. We recorded 3 parameters: time to recurrence of pain, time to conversion to arthroplasty and time to radiographic failure. Survival was estimated using the Kaplan-Meier method. The equality of the survival distributions was determined by the Log rank test. RESULTS: Implanted electrostimulator was a factor that increased the survival of hips in a pre-op Steinberg stage of II or below, while it remained unchanged if the stage was III or higher. CONCLUSIONS: The addition of an internal electrostimulator provides increased survival compared to core decompression alone at stages below III.

Long-term results of alumina-on-alumina hip arthroplasty for osteonecrosis.

Alumina-on-alumina bearings in THR may, in theory, provide an effective answer to osteolysis in young patients with ON of the femoral head. The purpose of this retrospective study was to report the long-term results of a series of 52 consecutive alumina THAs (41 patients) done for ON. The mean age of the patients at surgery was 41 years (range, 22-79 years). Cemented femoral stems with a 32-mm alumina head were used. Plain alumina cups were used and were either cemented (39 hips) or press-fit (13 hips). No patients were lost to followup. Sixteen hips have been revised. Aseptic loosening of the socket was the main cause of failure. At an average 16-year followup (range, 11-23.65 years), 26 hips were rated excellent and one hip was rated good. No osteolysis was observed and wear was undetectable. If revision for aseptic loosening was the end point, the rate of survival was 88.5% at 10 years for the socket and 100% at 10 years for the stem. With the alumina-on-alumina hip replacement done for ON, absence of osteolysis can be expected for as many as 24 years after the operation. New methods of socket fixation now are being explored.