Triple pelvic osteotomy (according to Tonnis and Kalchschmidt) in the treatment of acetabular dysplasia -: Mid-term results

Aim: The triple pelvic osteotomy according to Tonnis and Kalchschmidt has gained major significance in the surgical treatment of acetabular dysplasia in adolescents and adults. The curative and prophylactic potentials of this operative procedure are reviewed in this study by means of a clinical and radiological follow-up trial. Methods: 34 patients/38 hip joints treated by the triple pelvic osteotomy between 1996 and 2005 were reviewed clinically and radiologically with an average follow-up of 3.5 years. The radiological classification into grades of deviation was done according to Tschauner et al., clinically the preoperative Harris hip score was determined, as well as common epidemiologic parameters. At follow-up, the preoperatively determined radiological and clinical parameters were controlled and subjected to statistical analysis using Student's t-test for the comparison of means between two paired groups. Finally, the subjective assessment of the operation's result by the patients was registered. Results: A statistically highly significant amelioration of the Harris hip score, relevant radiological angles and grades of deviation could be demonstrated at follow-up. This fact coincided with a high or very high patient satisfaction in 81.7% of the cases. The conversion rate to alloarthroplasty was 2.6%. The complication profile was within the scope of similar elective hip surgeries. Conclusion: The triple pelvic osteotomy according to Tonnis and Kalchschmidt has shown in the present study a high and constant potential with regard to reduction/absence of disorders as well as a statistically highly significant amelioration of clinical scores and relevant radiological angles. In our experience, this surgical method can be regarded as the joint-preserving method of choice in the cardinal indication of adolescent and adult acetabular dysplasia.