CUSTOM UNCEMENTED HIP ARTHROPLASTY IN PATIENTS WITH DEVELOPMENTAL DYSPLASIA OF THE HIP

Abstract

Introduction: Developmental dysplasia of the hip (DDH) is a common cause of secondary osteoarthritis of the hip. The severity of the hip dysplasia varies considerably leading to a broad spectrum of reconstructive challenges. The custom CAD/CAM femoral stems offer a useful solution to fit and correct the abnormalities in the anatomy of the proximal femur.

Materials and Methods: The purpose of the study was to review at the functional and radiological outcome of uncemented CAD/CAM stems where the primary diagnosis is DDH. Uncemented sockets were used in all cases. Pre-operative planning consisted of a CT scan to assess the available acetabular coverage, estimate the degree of femoral anteversion and precisely evaluate the limb-length inequality. The hips were classified according to Crowe and Hartofilakidis. Patients with less than two-year follow up were excluded. The outcome was determined radiologically and using the Harris, Oxford and WOMAC scoring systems.

Results: Ninety-nine cases were identified and included in the study. The mean age of the group was 43.8 (range 26–79) with a female to male ratio was 4 to 1. The average follow up time was 5 years (range 24–118). The majority of the patients had excellent outcomes with a significant improvement in their clinical scores. The pre-operative scores were Harris Hip score 43.8 (range 9–81), Oxford 41.6 (range 19–59) and WOMAC 77.3 (range 10–120). Post operatively the scores have improved to Harris Hip Score 84.2 (range 38–99), Oxford 20.3 (range 12–48) and WOMAC 37.1 (range 24–92).

Conclusion: Total hip replacement for the sequelae of hip dysplasia is associated with high failure and complication rates. CAD/CAM stems afford a great deal of flexibility for the management of a broad spectrum of anatomical problems in these cases and provide a very useful alternative to modular prostheses. We present excellent medium term results.