ABSTRACT
We aimed to develop a clinically relevant delayed union/non-union fracture model to evaluate a cell therapy intervention repair strategy. Histology, three-dimensional (3D) microcomputed tomography (micro-CT) imaging and mechanical testing were utilized to develop an analytical protocol for qualitative and quantitative assessment of fracture repair. An open femoral diaphyseal osteotomy, combined with periosteal diathermy and endosteal excision, was held in compression by a four pin unilateral external fixator. Three delayed union/non-union fracture groups established at 6 weeks--(a) a control group, (b) a cell therapy group, and (c) a group receiving phosphate-buffered saline (PBS) injection alone--were examined subsequently at 8 and 14 weeks. The histological response was combined fibrous and cartilaginous non-unions in groups A and B with fibrous non-unions in group C. Mineralized callus volume/total volume percentage showed no statistically significant differences between groups. Endosteal calcified tissue volume/endosteal tissue volume, at the center of the fracture site, displayed statistically significant differences between 8 and 14 weeks for cell and PBS intervention groups but not for the control group. The percentage load to failure was significantly lower in the control and cell treatment groups than in the PBS alone group. High-resolution micro-CT imaging provides a powerful tool to augment characterization of repair in delayed union/non-union fractures together with outcomes such as histology and mechanical strength measurement. Accurate, nondestructive, 3D identification of mineralization progression in repairing fractures is enabled in the presence or absence of intervention strategies.
Subject(s)
Cell Transplantation , Disease Models, Animal , Fractures, Ununited/diagnostic imaging , Rats, Sprague-Dawley , Tomography, X-Ray Computed , Animals , Diathermy , External Fixators , Female , Femoral Fractures/diagnostic imaging , Femoral Fractures/pathology , Femoral Fractures/therapy , Femur/diagnostic imaging , Femur/pathology , Femur/physiology , Fractures, Ununited/pathology , Fractures, Ununited/therapy , Rats , Weight-Bearing/physiologyABSTRACT
A retrospective review of 991 primary total hip arthroplasties was performed to determine the incidence of rapidly progressive osteoarthrosis of the hip joint. Thirty-four patients (35 hips) were identified (3.5%). Females were predominantly affected (85%). A history of hypertension and regular non-steroidal anti-inflammatory drug use was significantly more common in those with rapid progression as compared to the normally progressive group. Transfusion requirements were also significantly greater for the rapidly progressive group. Patient age and operating time were both greater in those with rapid progression, but neither proved statistically significant. No significant difference was noted when comparing the affected side, body mass index or the pre-operative range of hip movements, ESR or Oxford Hip Score. From the radiographs, twenty cases were classified as type I (rapid), 11 type II (moderate) and 3 type III (delayed). Wear distribution was predominantly superolateral (85%) and anterosuperior (97%). All patients were treated by total hip arthroplasty. At latest follow-up (average, 18 months; range, 13-36 months) there was no significant difference in the Oxford Hip Score between the normally progressive and rapidly progressive groups. All radiographs were satisfactory. Total hip arthroplasty in these cases is technically challenging. When identified, such individuals should be given priority treatment due to the potentially rapid and extensive loss of bone stock that can occur. (Hip International 2004; 14: 217-22).
