Purpose: In the treatment of acetabular dysplasia in adolescents and adults the triple osteotomy according to Tonnis is a common procedure. This retrospective study were undertaken to evaluate the clinical and radiological results and quality of life after triple osteotomy according to Tonnis.

Material and Methods: In our retrospective study 43 patients (f=32, m=11) with acetabular dysplasia after triple osteotomy procedure with an average age of 21.8 years (SD=7.6) were evaluated. The average follow-up was 9.3 years (range 0.6–19.1 ys). For clinical evaluation, the Harris Hip Score was used. The pre- and postoperative x-rays in ap and faux profile plane were evaluated for the CE-, VCA-, AC-, ACM-angle and the acetabular index. Quality of life was evaluated by the SF-36-health questionnaire.

Results: 48,8% of our patients achieved excellent or good results in the Harris Hip Score and 65,1% of the patients considered the subjective postoperative result as excellent or good. The CE angle improved significantly from preoperatively 8.8 to postoperatively 34.5 degrees. The VCA angle according to Lequesne and Seze improved significantly from 30.7 to 50.9 and the AC angle from 10.2 to 19.5 degrees. The ACM angle decreased significantly from 53.3 to 56 degrees and the acetabular index increased from 33.4 to 37.3 postoperatively. Range of motion of the operated extremity decreased significantly for hip flexion and internal roation. SF-36-health questionnaire results of the patient group showed significant differences for the parameters physical function, bodily pain and emotional role compared to those of a healthy reference group of the same age.

Four patients showed a pseudarthrosis of the ischial or pubic bone. Three patients had persisting pain of the pseudarthrosis and needed another operative procedure. Hypaesthesia in the area of N. cutaneus femoris lateralis occurred in seven cases.

Conclusion: The results of the operative treatment of an acetabular dysplasia with a triple osteotomy procedure according to Tonnis showed a satisfactory outcome, even though significant functional deficits and deficits of quality of life could be demonstrated in middle and long term follow-up.