Aim. Aim of this monocentric, prospective study was to evaluate the safety, efficacy, clinical and radiographical results at 24-month follow-up (N = 6 patients) undergoing hip revision surgery with severe acetabular bone defects (Paprosky 2C-3A-3B) using a combination of a novel phase-pure betatricalciumphosphate - collagen 3D matrix with allograft bone chips. Method. Prospective follow-up of 6 consecutive patients, who underwent revision surgery of the acetabular component in presence of massive bone defects between April 2018 and July 2019. Indications for revision included mechanical loosening in 4 cases and history of hip infection in 2 cases. Acetabular deficiencies were evaluated radiographically and CT and classified according to the Paprosky classification. Initial diagnosis of the patients included osteoarthritis (N = 4), a traumatic fracture and a congenital hip dislocation. 5 patients underwent first revision surgery, 1 patient underwent a second revision surgery. Results. All patients were followed-up radiographically with a mean of 25,8 months. No complications were observed direct postoperatively. HHS improved significantly from 23.9 preoperatively to 81.5 at the last follow-up. 5 patients achieved a defined good result, and one patient achieved a fair result. No periprosthetic joint infection, no dislocations, no deep vein thrombosis, no vessel damage, and no complaint about limbs length discrepancy could be observed. Postoperative dysmetria was found to be + 0.2cm (0cm/+1.0cm) compared to the preoperative dysmetria of − 2.4 cm (+0.3cm/−5.7cm). Conclusions. Although used in severe acetabular bone defects, the novel phase-pure betatricalciumphosphate - collagen 3D matrixshowed complete resorption and replacement by newly formed bone, leading to a full implant integration at 24 months follow-up and thus represents a promising method with excellent bone regeneration capacities for complex cases, where synthetic bone grafting material is used in addition to autografts

Introduction. Orthopaedic rehabilitation of adolescences and young adults with high dislocation of the femur is rather challenging. The role of palliative salvage procedures is controversial enough in the cohort of patients. Materials and Methods. Treatment outcomes of 10 patients with congenital hip dislocation were analyzed. Mean age at intervention was 17,8 years (15–22). The grade of dislocation were assessed according to Eftekhar: type C − 2, type D − 8. The mean baseline shortening was 4.7±0.36 cm. All subjects underwent PSO with the Ilizarov method. Another osteotomy for lengthening and realignment was produced at the boundary of the upper and middle third of the femur. The mean time in the Ilizarov frame was 5.3 months. Results. The mean follow-up was 2.6±.1 years (range, 15 to 32 years). Limb shortening of 1 cm to 1. 1. /. 2. cm was observed in four cases. Functional outcomes according to d'Aubigne-Postel were: Pain 4,4±0,15 points. ROM − 4,1±0,3 points. Walking ability − 4,5±0,2 points. Two cases had good results (15–17 points), and seven patients had fair outcomes (12–14 points). A poor result (7 points) was recorded in one female patient 28 years after PSO followed by THA. Conclusions. Hip reconstruction with the Ilizarov method can be used in specific clinical situations as an alternative salvage procedure to delay THR in young patients with high dislocation of the femur