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A new method for the assessment of reduction tension during open reduction in patients with developmental dysplasia of the hip.

OBJECTIVES
This study aims to describe our standardized method for evaluating the tension of reduction around the hip joint during open reduction in patients with developmental dysplasia of the hip (DDH).


PATIENTS AND METHODS
We retrospectively evaluated 67 pediatric patients (8 males, 59 females; mean age 21.9±11.1 months; range, 9 to 67 months) who were performed open reduction or open reduction with concomitant pelvic and/or femoral osteotomy for DDH at our clinic between January 2009 and March 2014. The amount of distraction between femoral head and acetabulum was measured to evaluate the tension of reduction during surgery. Factors associated with avascular necrosis (AVN) such as age at reduction, presence of concomitant pelvic and/or femoral shortening osteotomy, and severity of dislocation were determined.


RESULTS
Statistically significant association was found between the presence of femoral osteotomy, severity of dislocation, and amount of distraction and AVN. The incidence of AVN was 38.8% (10 grade I, 12 grade II, 3 grade III, and one grade IV AVN). Cut-off value for the amount of distraction to prevent the development of AVN was calculated as 4 mm.


CONCLUSION
According to our study findings, we advise using our technique for the evaluation of the tension of reduction around the hip joint and performing tension free reduction in the treatment of DDH to minimize the risk of AVN development.