Purpose: The aim of this long-term study was to evaluate whether the Lance acetabuloplasty for congenital dysplasia of the hip causes a growth disturbance of the acetabular roof during or after puberty.
Method: 71 hips of 58 patients were followed clinically and radiologically over a maximum time of 16 years after the operative procedure of a Lance acetabuloplasty. The average age of the patients at the time of operation was 2.8 years (1-6 years). In order to assess the growth of the acetabulum in the early and long-term postoperative phase quantitative parameters (acetabular index of Hilgenreiner, CE angle of Wiberg, ACM angle of Idelberger) as well as qualitative parameters (disturbance of the ossification of the acetabulum and the femoral head) were determined in standardized X-rays of the pelvis, done routinely 6 months, 3 years, 5 years, 8 years and at an average of 11 years as the last follow-up examination after the operation. The assessment of these metrical parameters were carried out in accordance to the classification of the study-group "hip dysplasia" of the DGOT (normal--slight pathological--serious pathological) respecting the different age-groups and degrees of dysplasia.
Results: Although in the early postoperative phase the acetabular roof showed a positive development (65% of the CE angles could be considered normal 3 years after operation), the further growth of the acetabulum was disturbed in the period of puberty (8 years after operation only 33% of the CE angles could be considered normal, 51% were extremely pathological). And also in the last X-ray control after an average follow-up time of 11 years a significant retardation of the acetabular roof was seen in 51% of all cases.
Conclusion: The Lance acetabuloplasty seems to damage the Ossa acetabuli, which are as centers of ossification the essential anatomic structures for the growth of the acetabular rim in adolescence.
Clinical relevance: Other procedures such as the Salter osteotomy are to be preferred for the therapy of hip dysplasia.