Evaluation of new radiographic parameters regarding the need for secondarysurgical intervention after closed reduction in developmental dysplasia of the hip

Aim: Developmental dysplasia of the hip (DDH) is one of the most common congenital defects of the musculoskeletal system, and includes a wide range of conditions such as hip dislocation, subluxation and acetabular dysplasia. The key to changing the natural history of DDH is early diagnosis and achieving stable concentric reduction as early as possible; This promotes normal acetabular development to occur and prevents or minimizes late acetabular dysplasia. Although there are studies in the literature about estimating the need for additional surgical intervention, a parameter that can precisely predict the need for surgical intervention has not been determined. The aim of this study is to evaluate whether new radiological parameters are useful in predicting the need for surgical intervention in patients with DDH undergoing closed reduction. Materials and Methods: Between August 2010 and September 2020, the medical records and radiological results of the patients who applied to the Department of Orthopedics and Traumatology at İnönü University Turgut Özal Medical Center for unilateral DDH who received conservative treatment and came for routine follow-up were evaluated retrospectively. Three radiological measurement parameters were determined to estimate residual dysplasia and the need for surgical intervention as secondary management in patients with unilateral DDH treated with closed reduction. After closed reduction of the hip, we evaluated the changes in the length of the acetabular roof, the osseous change at the superolateral edge of the acetabulum, and the remodeling and extension of the acetabulum laterally, comparing these data with the normal side in the pre-operative period, and in the postoperative 3rd and 6th months. At the same time, cutoff values were determined statistically in order to determine the limits of undergoing secondary surgery after closed reduction. Results: 2 (5.4%) of the patients included in the study were male and 34 (94.4%) were female. When closed reduction was applied, the mean age of the patients was 7 months ± 2 months (5-9) and 10.5 months ± 2.5 months (8-12) at the last control examination. Eight patients (22.2%) had right side involvement and 28 patients (77.7%) had left hip involvement. Arthrography with closed reduction was performed in 20 VI patients (55.5%) and additional tenotomy was performed in 4 patients (11%). Secondary surgical treatment was performed in 13 patients (36%) whose acetabular dysplasia, dislocation or subluxation findings continued during their follow-up. Avascular necrosis developed in 2 patients who underwent surgical intervention as secondary treatment. In the remaining 23 patients (64%) significant clinical and radiological signs of improvement were recorded at the end of the 3rd and 6th months and their follow-up was continued without the need for a secondary procedure. The average value of the acetabular roof length of the dislocated side before closed reduction was calculated as 15.6 mm (9.4-20), 17.4 mm (11-21.1) at the 3rd month and 17.9 mm (14.4-22.1) at the 6th month. The mean value of the acetabular roof length of the contralateral nondislocated hip was calculated as 15.6 mm (13-19.2) in the preoperative period, 16.8 mm (13.8-19.7) in the 3rd month and 18.2 mm (14.6-21) at the 6th month. The cut-off values of this parameter for surgical intervention as an additional procedure were found to be ≤ 16mm at the 3rd month and ≤ 15.6 mm at the 6th month. Before closed reduction, the length of the bony protrusion on the outer edge of the acetabulum of the dislocated side was determined to be zero (0). The mean value was 2.6 mm (0-3.2) in the 3rd month and 2.7 mm (0-2.3) in the 6th month. The cut-off values of this parameter for surgery as an additional procedure were found to be ≤ 2.5 mm at the 3rd month and ≤ 2.5 mm at the 6th month. Before closed reduction, the mean value of the lateral extension of the dislocated acetabulum was 12.9 mm (8.7-17.0), 15.6 mm (10.0-18.5) in the 3rd month and 16.0 mm (11.4-19.4) in the 6th month. The mean values of the contralateral non-dislocated hip were calculated as 14.6 mm (12.3-18.1) in the preoperative period, 16 mm (13.0-22.5) at the 3rd month, and 17.0 mm (13.2-21.1) at the 6th month. The cut-off values of this parameter were found to be ≤15.8 mm at the 3rd month and ≤15.5 mm at the 6th month. Conclusion: The necessity of surgical intervention as a secondary procedure for DDH after closed reduction is estimated based on radiographic parameters. However, suggestions vary regarding which reference point should be used when making radiographic measurements. It is very important to use a highly reliable radiographic parameter to predict residual hip dysplasia in planning and managing DDH treatment. We believe that the new radiographic parameters evaluated in this study will contribute to the literature in determining the need for surgical intervention as a secondary procedure in patients with DDH undergoing closed reduction. Keywords: Developmental dysplasia of the hip, Closed reduction, Radiological parameter, Secondary procedure.