Redislocation After Posteromedial Open Reduction in Developmental Dysplasia of the Hip: Analyzing the Risk Factors and Determining the Optimal Treatment Method.

Background: Redislocation, which is one of the most serious problems in developmental dysplasia of the hip (DDH), might occur because of several reasons. Regardless of the treatment, redislocations are reported to be associated with high complication rates in the literature. Our objective was to identify the risk factors for redislocation in the patients treated for DDH and to determine the optimal treatment method for redislocations.

Methods: Patients with DDH who were treated with the limited posteromedial approach in our clinic between 1993 and 2021 and followed up prospectively were examined in this single-centered study. The participants were assigned into 2 groups: a study group consisting of 25 hips of 17 patients with redislocation and a control group consisting of 502 hips of 390 patients without redislocation. To determine the risk factors for redislocation, demographic data, known risk factors for DDH, preoperative Tönnis stage, and whether the capsule was opened or not were evaluated. To determine the optimal treatment method, a subgroup analysis based on applied treatment (closed reduction and cast replacement vs. repeating open reduction) was conducted, and recurrent redislocation, complication, and secondary surgery rates were evaluated.

Results: Bilaterality and high-grade hip dislocations were found to be associated with higher odds ratio (OR) for redislocation [ P =0.007, OR=3.64, 95% confidence interval (CI), 1.3 to 8.8; and P =0.006, OR=4.52, 95% CI, 1.37 to 14.91, respectively]. Recurrent redislocation and complication rates were found to be significantly higher in redislocations treated with closed reduction and cast replacement ( P =0.007 and P =0.015, respectively).

Conclusions: Bilaterality and higher preoperative Tönnis stage are critical risk factors for redislocation after open reduction in DDH. It should be kept in mind that closed reduction and cast replacement is associated with higher rates of recurrent redislocation and complications, and redislocation cases should be treated by repeating open reduction.

Level Of Evidence: Level II-therapeutic study.