The 3-dimensional configuration of the typical hip and knee in diastrophic dysplasia.

PURPOSE: Surgical correction of the hip and knee in patients with diastrophic dysplasia is extremely difficult secondary to the markedly distorted pathoanatomy of both the bone and soft tissues. The objective of this study is to provide a 3-dimensional model and carefully and extensively describe the pathoanatomy of the diastrophic hip and knee.

METHODS

Three-dimensional computer model reconstructions were developed based on clinical, radiographic, and surgical observations performed "meticulously" by a single surgeon on 110 hips in 55 patients. An additional 13 patients seen by another surgeon were also reviewed. In addition to the clinical and radiographic evaluations, 10 computed tomographic scans were performed of the pelvis and hip areas and 53 arthrograms were done in 13 patients. Sixty-six patients underwent a myriad of operative procedures on the hip and proximal femur.

RESULTS

The typical pathoanatomy seen in cases of diastrophic dysplasia reflects the severe and rampantly progressive flexion deformity of the hip and knee with time, and the anatomical aberrations of development of the proximal femur and the knee joint, which are highlighted in our computer model. Replacement arthroplasty at the hip and knee may hold the only solution to adolescents and adults with advanced disease; however, the unavailability of long-term data precludes a reasonable management recommendation.

CONCLUSIONS

The disturbed pathoanatomy of the diastrophic dysplasia hip and knee reflects the difficulties in achieving any substantial surgical correction even with customization. This report provides the most extensive 3-dimensional pathoanatomical observations as yet presented in the literature.

LEVEL OF EVIDENCE: Level II.