Lateral growth arrest of the proximal femoral physis: a new technique for serial radiological observation.

PURPOSE: Lateral growth arrest is recognised as the most common form of avascular necrosis (AVN) seen in the management of developmental dysplasia of the hip (DDH). The purpose of this report is to present a new technique that is of benefit in the early identification and subsequent radiological monitoring of lateral growth arrest and which may permit appropriate timely surgical intervention.
METHODS: We performed a retrospective review of the medical records and serial radiographs of 11 patients (three males and eight females) with lateral growth disturbance in the proximal femoral physis. We devised a new technique (named the 'Tilt angle') for serial radiographic observation of lateral growth arrest.
RESULTS: This study included 11 hips in 11 patients. Ten patients had screw epiphyseodesis performed after progression of lateral growth arrest was noted. One patient did not have screw epiphyseodesis but the results for this patient are included, as they provide an interesting 'control' case for comparison. The average age of screw epiphyseodesis was 12 years. Seven patients demonstrated improvement in their tilt angle following screw epiphyseodesis (i.e. less valgus), one showed no change and two continued to decline.
CONCLUSIONS: Using a new technique to monitor the progression of lateral growth arrest, we noted that screw epiphyseodesis can be used for guided growth of the proximal femoral physis. This technique can be employed for serial radiographic observation of lateral growth arrest and can guide the clinician on the optimal timing of screw epiphyseodesis. Further studies are needed in order to clarify the optimal timing of screw epiphyseodesis.