The goal of the present study was to evaluate the results of a one-stage operation performed on dislocated hips in children with infantile cerebral palsy. Our data indicate that the one-stage operation is a quite useful method to treat hip dislocation in children with infantile cerebral palsy. Based on our experience we emphasize the use of an individual operation plan in every instance. In selected cases it seems to be justified to ignore an element of the method. We used the radiological findings for evaluation by comparing the geometric parameters in the affected hips before and after surgery. During the last ten years, 21 dislocated hips in 13 patients were operated on by the one-stage surgical technique used at the Department of Orthopaedic Surgery of University Medical School of Pécs. The technique consists of the following steps: open reduction, iliopsoas tendon transfer, and femoral varus derotational osteotomy with shortening, modified Tönnis acetabuloplasty, and open adductor tenotomy. Spastic diplegia occurred in eight children and hemiplegia in five. During this period, eight girls and five boys were operated, with 12 procedures on the right hip and 9 on the left. Mean age was 11.4 years. The average age of the children at the time of operations was 6.5 years. In eight hips of five children, all elements of the surgery were carried out in one sitting; in six hips of four children the surgery was performed without acetabuloplasty. In nine hips of seven children there was no need for open reduction, and in six hips of five children we used deep frozen allograft to perform acetabuloplasty. A varus derotational femoral osteotomy with shortening was a part of the surgical approach in all cases. We evaluated Hilgenreiner (H), Wieberg (CE) and collodiaphyseal (CCD) angle preoperatively and postoperatively. The average preoperative H angle decreased from 39.7 to 24 degrees postoperatively. The average preoperative CE angle increased from minus 18.6 to 31.9 degrees postoperatively. The minus means that all of the patients had dislocation in their hips. The average preoperative CCD angle decreased from 165.2 to 131.4 degrees postoperatively. The results were evaluated by the modified Severin classification based on age and anatomical changes of hips: 17 cases were evaluated as excellent, 2 as good, and 2 as acceptable. We did not see any complications such as avascular necrosis of the femoral head, absolute revalgisation (compared to the opposite side), subluxation, re-dislocation, or disturbed development of the acetabulum.
To investigate the effect of instability on the remodelling of a minor articular surface offset, we created a 0.5 mm coronal step-off of the medial femoral condyle in 12 New Zealand white rabbits and transected the anterior cruciate ligament (ACL). A control group of 12 rabbits had only ACL resection and the opposite knee was used as the non-operated control. The osteoarthritic changes at 6, 12 and 24 weeks after surgery were evaluated histologically. In addition, changes in the immunological detection of 3-B-3(-) and 7-D-4 chondroitin-6-sulphate epitopes were determined because of the previous association of such changes with repair of cartilage and early osteoarthritis. In the instability/step-off group there was rapidly progressing focal degeneration of cartilage on the high side of the defect, not seen in previous step-off studies in stable knees. The rest of the femoral condyles and the tibial plateaux of the instability/step-off group had moderate osteoarthritis similar to that of the instability group. 3-B-3(-) was detectable in the early and the intermediate stages of osteoarthritis but no staining was seen in the severely damaged cartilage zones. Immunoreactivity with 7-D-4 increased as degeneration progressed. Our findings have shown that even a minor surface offset may induce rapid degeneration of cartilage when the stability of the knee is compromised.
