High trochanter location: Natural history or complication following treatment of Perthes' disease?

Background. In Perthes' disease femoral head deformities can be accompanied by high location of the greater trochanter and diminished shaft-neck angle, causing decreased joint stability and diminished hip function. The aim of our study was to compare head-trochanter relationships in hips treated for Perthes' disease using surgical and non-surgical methods. Material and methods. The clinical material consisted of 61 children (68 hips) treated in our hospital from 1990 to 1994; 32 hips were treated conservatively, while 36 hips were operated. The mean observation time was 7.7 years. We re-examined X-rays done at onset, after 3-6 months of treatment, and at final follow-up. The projected shaft-neck angle, ATD (Edgren), and degree of head involvement (Catteral and Herring) were evaluated, while the Stulberg classification was used for outcome evaluation. In clinical examination we looked for Trendelenburg sign, limping, and leg length discrepancy. Results. The value of shaft-neck angle and ATD were correlated with age, sex, degree of head containment, and method of treatment. In boys, comparatively low ATD values were found in both treatment groups. In girls the ATD values were considerably lower in operated hips. High trochanter location and diminished shaft-neck angle had no statistical effect on clinical outcome. Conclusion. The natural course of Perthes' disease causes decreased ATD, regardless of treatment type. In our operative technique, containment may be achieved more by extension (anteflexion) osteotomy of the femur than by pure varisation osteotomy. We found no indication for epiphysiodesis of the greater trochanter combined with anteflexion osteotomy of the femur.