Introduction: With the growing number of primary knee arthroplasties, the number of revision operations is also increasing. The large number of unicondylar replacements carried out in the 1980’s, due to lack of modern total condylar implants, grant the revision techniques an outstanding significance in Hungary. One of the main issues of modern revision techniques is the management of bone defects, which can be solved by different methods documented in literature.

Aim of study: The aim of our study was to investigate the success and feasibility of the various defect management techniques by evaluating the results of revision knee prosthetic surgeries carried out at our clinic.

Patients and methods: Femoral and tibial bone defects had to be solved with revision surgeries in 35 cases, all performed due to aseptic loosening of uni- and total condylar prostheses implanted earlier. For filling of bone defects, metal augmentation of the prostheses was applied in 9 cases, allografts from bone bank were used in 11 cases, own cancellous bone was applied in 20 cases. Results were prospectively analysed with the help of the knee society rating system, with an average follow-up of two and a half years.

Results: Revision interventions were successful in 34 cases, detailed results are revealed in the presentation, complemented with case presentations. In a single case, repeated intervention surgery is indicated due to disorganisation of the structural allograft and the resulting loosening of the tibial component.

Conclusion: The success of the various bone replacement techniques, completed with adequate indication could be proven in all cases. The unsuccessful case proved that allograft incorporation should be supported by appropriate stem augmentation of the tibial component. In order to perform successful revision knee arthroplasty, we consider it fundamentally important to have a wide variety of allografts from bone bank and a modern knee prostheses system application already during primary implantations.

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.