Evaluation of Test of Stability as an Aid for Osteotomy in Open Reduction for Developmental Dysplasia of Hip

Background: Developmental dysplasia of hip (DDH) represents a spectrum of anatomic abnormalities that can result in permanent disability. The goals of treatment are to create normal anatomy of the proximal femur and acetabulum and then to maintain that anatomy to allow normal development of hip. Our aim was to identify significance of the test of stability in planning of appropriate osteotomy during open reduction in order to achieve stable concentric reduction in DDH in terms of Severin’s clinical and radiological outcome.
Materials and Methods: In this study, 50 children with DDH, which required open reduction and osteotomy for stable concentric reduction, were admitted in Orthopaedic department of SIMS/Services Hospital from Mar 2004 - May 2008. Clinical assessment and radiograph of pelvis with both hips in anteroposterior view was done for all the patients to confirm the diagnosis. After the confirmation of diagnosis surgery was planned and during surgery test of stability applied. Test of stability are the maneuvers which included flexion, internal rotation and abduction performed by the operating surgeon to assess the need for a concomitant osteotomy. If hip found stable in internal rotation and abduction, varus derotational femoral ostetomy was done and fixed with 1/3rd tubular plate. If hip required flexion it was treated with innominate osteotomy and fixed with K-wires. Those hips which required flexion, abduction and internal rotation for concentric reduction were treated with both ostetomies and fixed with K-wire & plate. Postoperatively all the patients were applied hip spica. A descriptive and analytical statistical analysis was performed on SPSS, version 13.
Results: The mean age of patients was 4 years (Mean ± SD: 4 ± 1.31), youngest patient being 3 years of age and oldest 7 years. Sex distribution with female to male ratio was 1.8:1. On an average follow up of 3.2 years Severin’s clinical outcome for 42 (84%) patients was excellent, 7 (14%) was good and 1 (2 %) was poor. P-value was 0.001. Severin’s radiological outcome for 40 (80%) patients was excellent and for 10 (20%) patients was good. P value was 0.112.
Conclusion: The test of stability is simple and effective aid for osteotomy in open reduction for developmental dysplasia of hip with excellent clinical and radiological results measured according to severin’s classification.