Calcium-phosphate ceramics and polysaccharide-based hydrogel scaffolds combined with mesenchymal stem cell differently support bone repair in rats.

Research in bone tissue engineering is focused on the development of alternatives to autologous bone grafts for bone reconstruction. Although multiple stem cell-based products and biomaterials are currently being investigated, comparative studies are rarely achieved to evaluate the most appropriate approach in this context. Here, we aimed to compare different clinically relevant bone tissue engineering methods and evaluated the kinetic repair and the bone healing efficiency supported by mesenchymal stem cells and two different biomaterials, a new hydrogel scaffold and a commercial hydroxyapatite/tricalcium phosphate ceramic, alone or in combination.Syngeneic mesenchymal stem cells (5 × 105) and macroporous biphasic calcium phosphate ceramic granules (Calciresorb C35®, Ceraver) or porous pullulan/dextran-based hydrogel scaffold were implanted alone or combined in a drilled-hole bone defect in rats. Using quantitative microtomography measurements and qualitative histological examinations, their osteogenic properties were evaluated 7, 30, and 90 days after implantation. Three months after surgery, only minimal repair was evidenced in control rats while newly mineralized bone was massively observed in animals treated with either hydrogels (bone volume/tissue volume = 20%) or ceramics (bone volume/tissue volume = 26%). Repair mechanism and resorption kinetics were strikingly different: rapidly-resorbed hydrogels induced a dense bone mineralization from the edges of the defect while ceramics triggered newly woven bone formation in close contact with the ceramic surface that remained unresorbed. Delivery of mesenchymal stem cells in combination with these biomaterials enhanced both bone healing (>20%) and neovascularization after 1 month, mainly in hydrogel.Osteogenic and angiogenic properties combined with rapid resorption make hydrogels a promising alternative to ceramics for bone repair by cell therapy.

Clinical and radiological outcomes with the Charité artificial disc: a 10-year minimum follow-up.

This is the first report of clinical and radiologic outcomes for the CHARITE artificial disc with a minimum follow-up of 10 years. A total of 107 patients indicated for total lumbar disc replacement were implanted with the CHARITE prosthesis. Of these 107, 100 were followed for a minimum of 10 years (range 10-13.4 years). A total of 147 prostheses were implanted with 54 one-level and 45 two-level procedures and 1 three-level procedure. The prostheses were placed through a standard anterior retroperitoneal approach. Clinically, 62% had an excellent outcome, 28% had a good outcome, and 10% had a poor outcome. Of the 95 eligible to return to work, 88 (91.5%) either returned to the same job as prior to surgery or a different job. These included 63.2% (12) of those working in heavy labor employment returning to the same job. Mean flexion/extension motion was 10.3 degrees for all levels (12.0 degrees at L3-L4, 9.6 degrees at L4-L5, 9.2 degrees at L5-S1). Mean lateral motion was 5.4 degrees . In the sagittal plane, 9 (6.1%) were anterior of geometric center, 50 (34.0%) were centered, and 88 (59.9%) were posterior of center. In the frontal plane, 110 (75%) were centered, and 37 (25%) were noted to be lateral to center. Slight subsidence was observed in two patients, but they did not require further surgery. No subluxation of the prostheses and no cases of spontaneous arthrodesis were identified. There was one case of disc height loss of 1 mm. Five patients required a secondary posterior arthrodesis. A good or excellent clinical outcome rate of 90% and a return to work rate of 91.5% compare favorably with results described in the literature for fusion for the treatment of lumbar degenerative disc disease. With a minimum follow-up of 10 years, the CHARITE artificial disc demonstrated excellent flexion/extension and lateral range of motion with no significant complications.

Long-term results of alumina-on-alumina hip arthroplasty for osteonecrosis.

Alumina-on-alumina bearings in THR may, in theory, provide an effective answer to osteolysis in young patients with ON of the femoral head. The purpose of this retrospective study was to report the long-term results of a series of 52 consecutive alumina THAs (41 patients) done for ON. The mean age of the patients at surgery was 41 years (range, 22-79 years). Cemented femoral stems with a 32-mm alumina head were used. Plain alumina cups were used and were either cemented (39 hips) or press-fit (13 hips). No patients were lost to followup. Sixteen hips have been revised. Aseptic loosening of the socket was the main cause of failure. At an average 16-year followup (range, 11-23.65 years), 26 hips were rated excellent and one hip was rated good. No osteolysis was observed and wear was undetectable. If revision for aseptic loosening was the end point, the rate of survival was 88.5% at 10 years for the socket and 100% at 10 years for the stem. With the alumina-on-alumina hip replacement done for ON, absence of osteolysis can be expected for as many as 24 years after the operation. New methods of socket fixation now are being explored.