Articular cartilage has a limited capacity for self-renewal. This article reports the development of a porous hydroxyapatite/ collagen (HAp/Col) scaffold as a bone void filler and a vehicle for drug administration. The scaffold consists of HAp nanocrystals and type I atelocollagen. The purpose of this study was to investigate the efficacy of porous HAp/Col impregnated with FGF-2 to repair large osteochondral defects in a rabbit model. Ninety-six cylindrical osteochondral defects 5 mm in diameter and 5 mm in depth were created in the femoral trochlear groove of the right knee. Animals were assigned to one of four treatment groups: porous HAp/Col impregnated with 50 ml of FGF-2 at a concentration of 10 or 100 mg/ml (FGF10 or FGF100 group); porous HAp/Col with 50 ml of PBS (HAp/Col group); and no implantation (defect group). The defect areas were examined grossly and histologically. Subchondral bone regeneration was quantified 3, 6, 12, and 24 weeks after surgery. Abundant bone formation was observed in the HAp/Col implanted groups as compared to the defect group. The FGF10 group displayed not only the most abundant bone regeneration but also the most satisfactory cartilage regeneration, with cartilage presenting a hyaline-like appearance. These findings suggest that porous HAp/Col with FGF-2 augments the cartilage repair process. ß

Bone fractures create five problems that must be resolved: bleeding, risk of infection, hypoxia, disproportionate strain, and inability to bear weight. There have been enormous advancements in our understanding of the molecular mechanisms that resolve these problems after fractures, and in best clinical practices of repairing fractures. We put forth a modern, comprehensive model of fracture repair that synthesizes the literature on the biology and biomechanics of fracture repair to address the primary problems of fractures. This updated model is a framework for both fracture management and future studies aimed at understanding and treating this complex process. This model is based upon the fracture acute phase response (APR), which encompasses the molecular mechanisms that respond to injury. The APR is divided into sequential stages of “survival” and “repair.” Early in convalescence, during “survival,” bleeding and infection are resolved by collaborative efforts of the hemostatic and inflammatory pathways. Later, in “repair,” avascular and biomechanically insufficient bone is replaced by a variable combination of intramembranous and endochondral ossification. Progression to repair cannot occur until survival has been ensured. A disproportionate APR—either insufficient or exuberant—leads to complications of survival (hemorrhage, thrombosis, systemic inflammatory response syndrome, infection, death) and/or repair (delayed- or non-union). The type of ossification utilized for fracture repair is dependent on the relative amounts of strain and vascularity in the fracture microenvironment, but any failure along this process can disrupt or delay fracture healing and result in a similar non-union. Therefore, incomplete understanding of the principles herein can result in mismanagement of fracture care or application of hardware that interferes with fracture repair. This unifying model of fracture repair not only informs clinicians how their interventions fit within the framework of normal biological healing but also instructs investigators about the critical variables and outputs to assess during a study of fracture repair.

Study Design:This is a prospective, randomized controlled trial.Objective:To prospectively assess the long-term clinical results of decompression alone, decompression plus fusion, and decompression plus stabilization for degenerative spondylolisthesis.Summary of Background Data:Symptoms of lumbar spinal stenosis due to degenerative spondylolisthesis originate from compression of the dural sac or nerve root. Essentially, this condition is treated by performing a decompression of neural structures. Posterolateral lumbar fusion and posterior pedicle-based dynamic stabilization are additional techniques performed to ensure improved prognosis. However, to date, the selection of a surgical procedure for lumbar spinal stenosis due to degenerative spondylolisthesis remains debatable, especially in terms of the addition of instrumentation because of the few available prospective, randomized studies.Materials and Methods:We randomly assigned patients who had 1 level lumbar spinal stenosis due to degenerative spondylolisthesis at the L4/5 level to undergo either decompression alone (decompression group), decompression plus fusion (fusion group), or decompression plus stabilization (stabilization group). Outcomes were assessed using the Japanese Orthopaedic Association and Visual Analogue Scale scores.Results:In total, 85 patients underwent randomization. The follow-up rate at 5 years was 86.4%. The fusion and stabilization groups showed higher blood loss and a longer operative time than the decompression group. The fusion group showed longer postoperative hospital stay than the decompression group. In terms of clinical outcomes, all scores significantly improved postoperatively, and these outcomes were maintained at 5 years postoperatively in each group. There were no significant differences among the groups at 1 and 5 years postoperatively.Conclusions:Additional instrumentation operation for low-grade (<30%) degenerative spondylolisthesis did not result in superior results to decompression alone at 1 and 5 years postoperatively.Level of Evidence:Level II.

While bracing is the standard conservative treatment for acute osteoporotic compression fracture, the efficacy of different brace treatments has not been extensively studied. We aimed to clarify and compare the preventive effect of the different brace treatments on the deformity of the vertebral body and other clinical results in this patient cohort. This multicenter nationwide prospective randomized study included female patients aged 65–85 years with acute one-level osteoporotic compression fractures. We assigned patients within four weeks of injury to either a rigid-brace treatment or a soft-brace treatment. The main outcome measure was the anterior vertebral body compression percentage at 48 weeks. Secondary outcome measures included scores on the European Quality of Life-5 Dimensions (EQ-5D), visual analog scale (VAS) for lower back pain, and the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ). A total of 141 patients were assigned to the rigid-brace group, whereas 143 patients were assigned to the soft-brace group. There were no statistically significant differences in the primary outcome and secondary outcome measures between groups. In conclusion, among patients with fresh vertebral compression fractures, the 12-week rigid-brace treatment did not result in a statistically greater prevention of spinal deformity, better quality of life, or lesser back pain than soft-brace.