Local soft tissue compression enhances fracture healing in a rabbit fibula.

Local soft tissue compression of fractures enhances fracture healing. The mechanism remains uncertain. Past studies have focused on intermittent soft tissue compression.

Parathyroid hormone (1-34) augments spinal fusion, fusion mass volume, and fusion mass quality in a rabbit spinal fusion model.

Study Design: The posterolateral rabbit spinal fusion model was used to assess the effect of intermittent parathyroid hormone on spinal fusion outcomes.

Objective: To test the hypothesis that intermittent parathyroid hormone (PTH) improves spinal fusion outcomes in the rabbit posterolateral spinal fusion model.

Summary Of Background Data: Spinal fusion is the definitive management for spinal deformity or instability, yet despite current technology, 5% to 40% of lumbar fusions result in pseudarthrosis.

The effects of COX-1 and COX-2 inhibitors on prostaglandin synthesis and the formation of heterotopic bone in a rat model.

Introduction: Traumatic heterotopic ossification (HO) is a common clinical condition associated with various orthopedic procedures that involve injury to soft tissues near bone. In this study, we tested the hypothesis that the prophylactic effects of NSAID's in the treatment of HO are mediated via inhibition of the COX-2 enzyme. Here we describe a rat model that simulates HO in the human that was used to test the above hypothesis.

Molded vascularized neo-ossicle formation in silicone chambers.

Vascularized bone grafts generally achieve their aims but are not used frequently owing to donor site morbidity and limited supply. To bioengineer an alternate vascularized bone graft, we developed a novel silicone bone reactor capable of producing vascularized neo-ossicles when appropriate osteoprecursor elements are included in the implanted chambers. Requirements for ossicle production were assessed in the model, including osteoprogenitor cells (donor bone marrow), osteoinductive signals (rhBMP2 or demineralized bone matrix), and osteoconductive matrix (Collagraft).

Early changes in prostaglandins precede bone formation in a rabbit model of heterotopic ossification.

We have tested the hypothesis that the formation of heterotopic ossification (HO) in a rabbit model is correlated with a local increase in specific prostaglandins that may modulate mechanisms of ossification. Rabbits were sacrificed at 1 to 21 days following the daily forcible flexion of immobilized knees. The extraction and analysis of prostaglandins (PG) E2, F2alpha, D2, 6-keto-F1alpha, and thromboxane B2 in vastus intermedius muscles of manipulated legs revealed increases compared to control hindlimbs for all five prostaglandins, albeit of differing magnitude.

Thrombin peptide (TP508) promotes fracture repair by up-regulating inflammatory mediators, early growth factors, and increasing angiogenesis.

Previous studies have shown that a single injection of thrombin peptide (TP508) accelerates fracture repair in a closed rat femoral fracture model. The present study was conducted to elucidate the molecular mechanisms of TP508 action using Affymetrix genome-scale profiling and to link early gene expression changes to fracture histology and bone strength changes. Treatment of femoral fractures with TP508 accelerated fracture repair as determined by destructive torsion testing.

Resorbable posterolateral graft containment in a rabbit spinal fusion model.

Object: The authors studied the effect of a resorbable graft containment device in a rabbit posterolateral lumbar spinal fusion model.

Methods: Twenty rabbits were divided into four groups: autologous bone graft (ABG), ABG with the MacroPore containment device (ABG + MP), demineralized bone matrix (DBM), and DBM with the containment device (DBM + MP). Fusion mass was assessed at 6 weeks with high-resolution radiography and volumetric computerized tomography.

Resorbable posterolateral graft containment in a rabbit spinal fusion model.

The effect of a resorbable graft containment device was evaluated in a rabbit posterolateral lumbar spinal fusion model. Twenty rabbits were divided into four groups: autogenous bone graft (ABG), ABG with the MacroPore containment device (MacroPore Biosurgery Inc, San Diego, Calif) (ABG+MP), demineralized bone matrix (DBM), and DBM with the containment device (DBM+MP). Fusion mass was assessed at 6 weeks with high resolution radiographs and volumetric computed tomography (CT).