[Total hip arthroplasty in congenital dysplasia of the hip: follow-up of a small-dimensioned, cemented straight stem].

Aim: The aim of this study is to report the survival and mid-term results including patient-relevant outcome measures with a small-sized cemented stem (CDH-stem) for the treatment of coxarthrosis secondary to developmental dysplasia of the hip.

Method: 33 total hip replacements were performed with the CDH stem, 29 of which (88 %) were included in the follow-up after an average of 7.6 years. According to the classification system of Hartofilakidis et al., 10 hips were classified as type 1, 15 as type 2, and 3 as type 3. Survival was predicted using Kaplan-Meier survivorship analysis with revision as the end point. Results were assessed using the Harris hip score, as well as the WOMAC and SF-36 as patient-relevant outcome measures.

Results: Survival at thirteen years was predicted to be 92.4 % for the stem and 87.6 % for the varying acetabular implants used. At the time of the final follow-up, the average Harris hip score was 82.45 points. The global WOMAC index averaged 2.1, the average SF-36 score was 66.2 points.

Conclusions: The data support the use of a small-sized cemented stem in small femora for total replacement of the dysplastic hip. To the best of our knowledge, this is the first study utilising the well validated WOMAC and SF-36 as patient-relevant outcome measures in this subgroup of patients.