Triple osteotomy of the pelvis in children and adolescents.

PURPOSE OF THE STUDY

To assess the results of Steel triple osteotomy on Developmental hip displacement (DDH) and Legg-Calvé-Perthes Disease (LCPD) cases utilising objective criteria based on measurements. All measurements were done by a co-author in a blind way. What concerns DDH, triple osteotomy was used in all cases in which authors felt to obtain a profit for a patient, so that hips with non-spherical head were operated on, too. On the other hand, as far as the experience with Steel osteotomy in LCPD is very limited, authors used this method presuming to obtain similar effect like with Salter osteotomy in younger patients.

MATERIAL

41 Steel osteotomies carried out in 29 cases of developmental dislocation of the hip (DDH), (age ranging 14-23 years) and in 12 cases of Legg-Calvé-Perthes disease (LCPD), (9-12 years of age) have been analysed. The follow-up duration was 4-12 years.

METHODS

Differently to the postulations of Dr. Steel, the inaugurator of triple osteotomy for DDH cases, indications in this study were also extended to aspherical congruencies and even incongruencies in DDH. Besides measuring CE, Sharp angles and Reimer's index, there was used subjectively descriptive classification of both initial conditions and results. The reached medialization and caudalization of the femoral head to Shenton line played an important role at the evaluating classification of the results. All obtained data were processed by the statistical methods to ascertain the influence of the operation. The same measuring methods were used for assessment of LCPD cases.

RESULTS

Fisher's exact test has shown the dependence of the results in DDH on the preoperative finding, reflecting the fact, that the triple osteotomy did not improve substantially the parameters of the more distorted hip joints. With the greater degree of joint deformity, the chance to obtain postoperative correction was less. Complete correction in all the DDH group was obtained in 20, partial correction in 7 cases and failure was found in 2 cases. Fisher exact test in LCPD demonstrated that results are not statistically dependent on the initial state. Complete correction in LCPD group was obtained in 10, partial correction in 1 and failure in 1 case.

DISCUSSION

It seems that the indication of Steel triple osteotomy in DDH must be highly well-considered concerning especially the containment of aspherical femoral head. Indication should be based on careful pre-operative planning using dynamic contrast arthrography helping to find the best position of femoral head through the additional femoral osteotomy. Hitherto rare application of Steel osteotomy for LCPD everywhere seems to be little irrespective of the fact that this operation can secure the containment of even deformed femoral head with the perspective of its subsequent remodelling as showed this study.

CONCLUSION

The historical postulate of inaugurator of triple osteotomy, concerning the sphericity of the femoral head as a condition sine qua non, seems to be broken especially in Legg-Calvé-Perthes disease. Even sattle deformity of femoral head can be corrected. What concerns the DDH the greater degree of joint deformity, especially aspherical incongruency brings about the risk of failure of surgical procedure. Nevertheless, in this study five out from seven cases of that degree of distortion obtained at least partial correction.