Rehabilitation of a Patient with Pirogoff Amputation and Two-year Follow-up: A Case Report.

BACKGROUND: Pirogoff amputation is a calcaneal amputation invented by Nicolás Pirogoff that involves partial preservation of the calcaneus. CASE: A 59-year-old woman was diagnosed with left Lisfranc and Chopart joint fracture-dislocation 9 months after a fall. The patient underwent debridement together with Pirogoff amputation and surgery to place an Ilizarov external fixator. Five months later, the patient was transferred to a rehabilitation hospital. Because of inadequate bone fusion, for 3 months after the amputation the patient underwent gait training with a patellar tendon weight-bearing orthosis to avoid loading the amputated side. After fusion of the bone, the patient was able to walk using a Syme prosthesis and a cane. Three months after discharge from the rehabilitation hospital, the patient was diagnosed with hallux osteomyelitis of the other foot that was associated with the exacerbation of hallux valgus. The patient underwent hallux correction surgery. Three and a half months after the second hospital admission, the patient was again admitted to the rehabilitation hospital. At the end of the rehabilitation program, the patient was able to walk using a cane and a prosthesis. DISCUSSION: Appropriate orthotic treatment and care of the non-amputated limb are of great importance in patients who have undergone a partial foot amputation.

Bone Defect Regeneration by a Combination of a ß-Tricalcium Phosphate Scaffold and Bone Marrow Stromal Cells in a Non-Human Primate Model.

BACKGROUND: Reconstruction of large bone defects is a great challenge in orthopedic research. In the present study, we prepared composites of bone marrow-derived stromal cells (BMSCs) and ß-tricalcium phosphate (ß-TCP) with three novel aspects: proliferation of BMSCs with continuous dexamethasone treatment, cell loading under low pressure, and use of autologous plasma as the cell loading medium. The effectiveness of the resulting composite for large bone-defect reconstruction was tested in a non-human primate model, and the bone union capability of the regenerated bones was examined. MATERIALS AND METHODS: Primary surgery: Bone defects (5 cm long) were created in the left femurs of nine cynomolgus monkeys with resection of the periosteum (five cases) or without resection (four cases), and porous ß-TCP blocks were transplanted into the defects. Secondary surgery: Bone marrow aspirates harvested from seven of the nine monkeys were cultured with dexamethasone, and BMSCs were obtained. BMSCs were suspended in autologous plasma and introduced into a porous ß-TCP block under low-pressure conditions. The BMSC/ß-TCP composites were transplanted into bone defects created at the same sites as the primary surgery. Bone union evaluation: Five regenerated femurs were shortened by osteotomy surgery 8 to 15 months after transplantation of the ß-TCP/BMSC composites, and bone union was evaluated radiographically. RESULTS: After the primary surgery and treatment with ß-TCP alone, one of the five periosteum-resected monkeys and two of the four periosteum-preserved monkeys exhibited successful bone reconstruction. In contrast, five of the seven cases treated with the ß-TCP/MSC composite showed successful bone regeneration. In four of the five osteotomy cases, bone union was confirmed. CONCLUSION: We validated the effectiveness of a novel ß-TCP/BMSC composite for large bone defect regeneration and confirmed the bone union capability of the regenerated bone.

Biomechanical evaluation of the rabbit tibia after implantation of porous hydroxyapatite/collagen in a rabbit model.

PURPOSE: Porous hydroxyapatite/collagen composite (HAp/Col) is an artificial bone substitute with excellent osteoconduction and sponge-like elasticity. However, the porosity of porous HAp/Col is as high as 95% and its mechanical strength is very poor. The aim of this study was to biomechanically analyze sites implanted with porous HAp/Col. METHODS: Rectangular cortical bone defects (3 × 8 mm) were made in the tibia of rabbits and filled with porous HAp/Col or porous ß-tricalcium phosphate or left vacant. The tibia was harvested at 4 or 12 weeks after surgery. The harvested specimens were analyzed using a micro-CT system, and the mechanical strength of the specimens was examined by torsion testing. RESULTS: Quantitative micro-CT analysis of the regenerated bone revealed that both bone substitutes equally facilitated bone regeneration. Biomechanical testing demonstrated that the torsional strength of HAp/Col-implanted sites was higher than that of the control (vs control: p = 0.030 and vs ß-TCP: p = 0.056). CONCLUSIONS: The results indicate that porous HAp/Col implantation is an effective strategy for recovery of the mechanical strength of bone defects.

Repair of osteochondral defects in a rabbit model using a porous hydroxyapatite collagen composite impregnated with bone morphogenetic protein-2.

Articular cartilage has a limited capacity for spontaneous repair, and an effective method to repair damaged articular cartilage has not yet been established. The purpose of this study was to evaluate the effect of transplantation of porous hydroxyapatite collagen (HAp/Col) impregnated with bone morphogenetic protein-2 (BMP-2). To evaluate the characteristics of porous HAp/Col as a drug delivery carrier of recombinant human BMP-2 (rhBMP-2), the rhBMP-2 adsorption capacity and release kinetics of porous HAp/Col were analyzed. Porous HAp/Col impregnated with different amounts of rhBMP-2 (0, 5, and 25 µg) was implanted into osteochondral defects generated in the patellar groove of Japanese white rabbits to evaluate the effect on osteochondral defect regeneration. At 3, 6, 12, and 24 weeks after operation, samples were harvested and subjected to micro-computed tomography analysis and histological evaluation of articular cartilage and subchondral bone repair. The adsorption capacity was 329.4 µg of rhBMP-2 per cm(3) of porous HAp/Col. Although 36% of rhBMP-2 was released within 24 h, more than 50% of the rhBMP-2 was retained in the porous HAp/Col through the course of the experiment. Defects treated with 5 µg of rhBMP-2 showed the most extensive subchondral bone repair and the highest histological regeneration score, and differences against the untreated defect group were significant. The histological regeneration score of defects treated with 25 µg of rhBMP-2 increased up to 6 weeks after implantation, but then decreased. Porous HAp/Col, therefore, is an appropriate carrier for rhBMP-2. Implantation of porous HAp/Col impregnated with rhBMP-2 is effective for rigid subchondral bone repair, which is important for the repair of the smooth articular surface.

Dexamethasone enhances osteogenic differentiation of bone marrow- and muscle-derived stromal cells and augments ectopic bone formation induced by bone morphogenetic protein-2.

UNLABELLED: We evaluated whether dexamethasone augments the osteogenic capability of bone marrow-derived stromal cells (BMSCs) and muscle tissue-derived stromal cells (MuSCs), both of which are thought to contribute to ectopic bone formation induced by bone morphogenetic protein-2 (BMP-2), and determined the underlying mechanisms. Rat BMSCs and MuSCs were cultured in growth media with or without 10-7 M dexamethasone and then differentiated under osteogenic conditions with dexamethasone and BMP-2. The effects of dexamethasone on cell proliferation and osteogenic differentiation, and also on ectopic bone formation induced by BMP-2, were analyzed. Dexamethasone affected not only the proliferation rate but also the subpopulation composition of BMSCs and MuSCs, and subsequently augmented their osteogenic capacity during osteogenic differentiation. During osteogenic induction by BMP-2, dexamethasone also markedly affected cell proliferation in both BMSCs and MuSCs. In an in vivo ectopic bone formation model, bone formation in muscle-implanted scaffolds containing dexamethasone and BMP-2 was more than two fold higher than that in scaffolds containing BMP-2 alone. Our results suggest that dexamethasone potently enhances the osteogenic capability of BMP-2 and may thus decrease the quantity of BMP-2 required for clinical application, thereby reducing the complications caused by excessive doses of BMP-2. HIGHLIGHTS: 1. Dexamethasone induced selective proliferation of bone marrow- and muscle-derived cells with higher differentiation potential. 2. Dexamethasone enhanced the osteogenic capability of bone marrow- and muscle-derived cells by altering the subpopulation composition. 3. Dexamethasone augmented ectopic bone formation induced by bone morphogenetic protein-2.

After repeated division, bone marrow stromal cells express inhibitory factors with osteogenic capabilities, and EphA5 is a primary candidate.

The differentiation capability of human bone marrow stromal cells (hBMSCs) is thought to deteriorate over multiple doubling processes. To clarify the deterioration mechanisms, the multilineage differentiation capabilities of short- and long-term passaged BMSCs were compared. Predictably, long-term passaged BMSCs showed reduced differentiation capacities compared to short-term passaged cells. Furthermore, a non-human primate heterotopic bone formation model demonstrated that long-term passaged BMSCs have bone formation capabilities but also exert inhibitory effects on bone formation. This finding indicated that long-term passaged BMSCs express higher levels of inhibitory factors than short-term passaged BMSCs do. Co-culture assays of short- and long-term passaged BMSCs suggested that the inhibitory signals required cell-cell contact and would therefore be expressed on the cell membrane. A microarray analysis of BMSCs identified ephrin type-A receptor 5 (EphA5) as an inhibitory factor candidate. Quantitative PCR revealed that among all members of the ephrin and Eph receptor families, only the expression of EphA5 was increased by BMSC proliferation. A gene knockdown analysis using siRNAs demonstrated that knockdown of EphA5 gene expression in long-term passaged BMSCs led to an increase in ALP mRNA expression. These results indicate that EphA5 may be a negative regulator of bone formation. A better understanding of the roles of the ephrin and Eph receptor families in hBMSCs may lead to alternative approaches for manipulating hBMSC fate. In addition, this avenue of discovery may provide new therapeutic targets and quality-control markers of the osteogenic differentiation capabilities of hBMSCs.

Massive bone reconstruction with heat-treated bone graft loaded autologous bone marrow-derived stromal cells and ß-tricalcium phosphate composites in canine models.

Bone marrow-derived stromal cells (BMSCs) contain mesenchymal stem cells that are capable of forming various mesenchymal tissues. We hypothesized that BMSCs and ß-tricalcium phosphate (ß-TCP) composites would promote the remodeling of large-sized autologous devitalized bone grafts; therefore, the aim of this study was to evaluate the effects of the composites on the remodeling of autologous devitalized bone grafts. Autologous BMSCs cultured in culture medium containing dexamethasone (10(-7) M) were loaded into porous ß-TCP granules under low-pressure. Theses BMSC/TCP composites were put into the bone marrow cavity of autologous heat-treated bone (femoral diaphysis, 65-mm long, 100°C, 30 min) and put back to the harvest site. In the contralateral side, ß-TCP without BMSC were used in the same manner as the opposite side as the control. Treatment with the BMSC/TCP composites resulted in a significant increase in thickness, bone mineral density, and matured bone volume of the cortical bone at the center of the graft compared to the control. Histological analysis showed matured regenerated bone in the BMSC loaded group. These results indicate that BMSC/TCP composites facilitated bone regeneration and maturation at the graft site of large-sized devitalized bone. This method could potentially be applied for clinical use in the reconstruction of large bone defects such as those associated with bone tumors.