Effect of treatment methods on avascular necrosis of the femoral head in patients with developmental dysplasia of the hip

Objective: Femoral head avascular necrosis (AVN) is one of the most important complications after treatment in developmental dysplasia of the hip (DDH). In this study, the effects of different conservative and surgical treatment methods on femoral head AVN were examined and it was aimed to investigate the risk factors that may cause AVN. Materials and Methods: Our study was designed as a single-center, retrospective clinical study. Patients diagnosed and treated for DDH at the Karadeniz Technical University Faculty of Medicine Orthopedics and Traumatology clinic between 1980 and 2020 were examined. Patients who received conservative treatment methods such as Pavlik harness, abduction brace, closed reduction and spica casting were included. Among the surgical treatment methods, patients who underwent open reduction with a medial approach, iliac osteotomy, femoral varus and/or derotation osteotomy were included in the study. The presence of AVN was evaluated and classified using Bucholz-Ogden and Kalamchi-MacEven criteria at annual follow-up and at the last follow-up after treatment. Results: 674 hips of 475 patients diagnosed with DDH were evaluated. While 418 patients (88%) were female, 57 patients (12%) were male. The average age at last follow-up was 7.38±6,0 years (3-39 years). At the last follow-up evaluation, AVN was observed in 4 (1.2%) of 313 hips that received only conservative treatment and in 37 (10.2%) of 361 hips that received surgical treatment. While AVN was not observed in 126 hips to which abduction brace was applied along with Pavlik harness, AVN was observed in 1 (0.7%) of 138 hips to which only abduction brace was applied. The AVN rate was found to be 8.9% in open reduction with the medial approach and 6.1% in hips with only closed reduction, and no significant difference was observed between the groups (p>0.05). The AVN rate was found to be significantly higher in spica casting in the human position after open reduction than in abduction position (p:0.005). In hips who underwent simultaneous open reduction and iliac osteotomy, AVN rate was 15.3% and the average age of surgery for hips with AVN was significantly higher (p:0.026). However, there was no significant difference in terms of AVN between Salter innominate osteotomy and Pemberton osteotomy performed in these hips (p>0.05). Conclusion: AVN rates were found low in conservative treatment methods applied at early ages in DDH and these treatment methods were safe in terms of AVN. The rates of AVN developing after closed reduction and open reduction were found to be similar. It has been observed that the AVN rate is low in open reduction with the medial approach, and the spica casting technique applied after open reduction has been found to have an effect on AVN. In this respect, age of treatment in DDH, selection of appropriate treatment according to age, and application of treatment methods with appropriate technique are very important in terms of femoral head AVN.