BACKGROUND Failure to fix unstable intertrochanteric fractures impairs return to daily activities.AIM To simulate five different internal fixation methods for unstable proximal femoral fractures.METHODS A three-dimens...BACKGROUND Failure to fix unstable intertrochanteric fractures impairs return to daily activities.AIM To simulate five different internal fixation methods for unstable proximal femoral fractures.METHODS A three-dimensional model of the femur was established from sectional computed tomography images,and an internal fixation model was established.Finite element analysis of the femur model was established,and three intertrochanteric fracture models,medial defect,lateral defect,and medial-lateral defects,were simulated.Displacement and stress distribution after fixation with a proximal femoral anti-rotation intramedullary nail(PFNA),integrated dual-screw fixation(ITN),PFNA+wire,PFNA+plate,and PFNA+wire+plate were compared during daily activities.RESULTS The maximum displacement and stress of PFNA and ITN were 3.51 mm/473 MPa and 2.80 mm/588 MPa for medial defects;2.55 mm/288 MPa and 2.10 mm/307 MPa for lateral defects;and 3.84 mm/653 MPa and 3.44 mm/641 MPa for mediallateral defects,respectively.For medial-lateral defects,reconstructing the medial side alone changed the maximum displacement and stress to 2.79 mm/515 MPa;reconstructing the lateral side changed them to 3.72 mm/608 MPa,when both sides were reconstructed,they changed to 2.42 mm/309 MPa.CONCLUSION For medial defects,intramedullary fixation would allow early low-intensity rehabilitation exercise,and ITN rather than PFNA reduces the risk of varus and cut-out;for lateral wall defects or weakness,intram-edullary fixation allows higher-intensity rehabilitation exercise,and ITN reduces the risk of varus.For both medial and lateral defects,intramedullary fixation alone will not allow early functional exercise,but locating lateral or medial reconstruction will.For defects in both the inner and outer sides,if reconstruction cannot be completed,ITN is more stable.展开更多
Background: To avoid the irritation of tendons and soft tissues as well as hardware-related problems, we designed an intramedullary fixation with bioabsorbable rods for the treatment of the metacarpal shaft fractures...Background: To avoid the irritation of tendons and soft tissues as well as hardware-related problems, we designed an intramedullary fixation with bioabsorbable rods for the treatment of the metacarpal shaft fractures. Methods: Five patients with nine shaft fractures of the fourth and fifth metacarpi were treated with intramedullary absorbable implants and followed up with an average of 4.2 months postoperatively. Results: At final follow-up, all patients achieved fracture union with no signs of inflammatory or subcutaneous effusion. There was no shortening, angulatory, or rotatory deformity. There was almost full active extension range of motion (ROM) of the metacarpophalangeal joints while the active flexion ROM of these joints was 80.7 ± 9.6°. hand was 94.0 ± 9.6%. X-rays showed that the arch of the second Compared with the contralateral hand, the grip strength of the injured to fifth metacarpal heads was smooth. There were no intramedullary lytic changes and soft tissue swellings. Conclusion: The intramedullary absorbable implants are a safe, simple, and practical treatment for fourth and filth metacarpal fractures with good early clinical outcomes and no significant complications.展开更多
Objective To provide morphological reference for the designing of the intramedullary nail fixation which suitable for Chinese by investigating the morphological characteristics of tibial medullary cavity. Methods Th...Objective To provide morphological reference for the designing of the intramedullary nail fixation which suitable for Chinese by investigating the morphological characteristics of tibial medullary cavity. Methods The morphological parameters of the 113 normal adult tibiale were measured on the X-ray photographs with the image analysis software. Results The total lengths of tibial medullary cavities were 299.49±11.03 mm(male) and 274.60± 6.77 mm(female), and the lengths of the narrow part were 66.36±3.90 mm(male) and 51.57±3.92mm(female). The end-points of narrow part were about 29.9 mm(male) and 26.09 mm(female)below the midpoints of medullary cavities. The radians of the longitudinal axes of medullary cavities were 2.53±1.27°(male) and 2.57±1.16°(female). The proximal opening K were 9.47±2.71(male) and 8.59±2.46(female). The distal opening K were 8.21± 2.93(male)and 7.65±2.87(female). Conclusion The morphology of tibial medullary cavity, the characteristic variety of radian and the opening K were very important references for designing the Chinese intramedullary nail fixation.展开更多
Objective: To better characterize nonunion endochondral bone healing and evaluate novel therapeutic approaches for critical size defect healing in clinically challenging bone repair, a segmental defect model of bone i...Objective: To better characterize nonunion endochondral bone healing and evaluate novel therapeutic approaches for critical size defect healing in clinically challenging bone repair, a segmental defect model of bone injury was adapted from the threepoint bending closed fracture technique in the murine femur.Methods: The mouse femur was surgically stabilized with an intramedullary threaded rod with plastic spacers and the defect adjusted to different sizes. Healing of the different defects was analyzed by radiology and histology to 8 weeks postsurgery. To determine whether this model was effective for evaluating the benefits of molecular therapy, BMP-2 was applied to the defect and healing then examined.Results: Intramedullary spacers were effective in maintaining the defect. Callus bone formation was initiated but was arrested at defect sizes of 2.5 mm and above, with no more progress in callus bone development evident to 8 weeks healing. Cartilage development in a critical size defect attenuated very early in healing without bone development, in contrast to the closed femur fracture healing, where callus cartilage was replaced by bone. BMP-2 therapy promoted osteogenesis of the resident cells of the defect, but there was no further callus development to indicate that healing to pre-surgery bone structure was successful.Conclusions: This segmental defect adaptation of the closed femur fracture model of murine bone repair severely impairs callus development and bone healing, reflecting a challenging bone injury. It is adjustable and can be compared to the closed fracture model to ascertain healing deficiencies and the efficacy of therapeutic approaches.展开更多
Coronal shear fractures of the femoral neck (CSFF) are the most challenging to treat among proximal femur fractures, directly affecting the life expectancy of patients with osteoporosis. However, an adequate osteosynt...Coronal shear fractures of the femoral neck (CSFF) are the most challenging to treat among proximal femur fractures, directly affecting the life expectancy of patients with osteoporosis. However, an adequate osteosynthesis method has not been elucidated yet. This study investigated the displacement direction of the femoral head fragment and its effect on the bone using finite element method. A finite element model for CSFF was developed from CT image data of a patient with osteoporosis using Mechanical Finder (ver. 11). Subsequently, finite element analyses were performed on six osteosynthesis models under maximum load applied during walking. The compressive stresses, tensile stresses, and compressive strains of each model were examined. The results suggested that the compressive and tensile stress distributions were concentrated on the anterior side of the femoral neck. Compressive strain distribution in the femoral head and neck was concentrated in four areas: at the tip of the blade or lag screw, the anteroinferior side of the blade or lag screw near the fracture site, and the upper right and lower left near the junction of the blade or lag screw and nail. Thus, the distribution of both these stresses revealed that the femoral head fragment was prone to anterior and inferior displacement. Distribution of compressive strains revealed the direction of the stress exerted by the osteosynthetic implant on the bone. The same results were observed in all osteosynthetic implants;thus, the findings could lay the foundation for developing methods for placing osteosynthetic implants less prone to displacement and the osteosynthetic implants themselves. In particular, the study provides insight into the optimal treatment of CSFF.展开更多
文摘BACKGROUND Failure to fix unstable intertrochanteric fractures impairs return to daily activities.AIM To simulate five different internal fixation methods for unstable proximal femoral fractures.METHODS A three-dimensional model of the femur was established from sectional computed tomography images,and an internal fixation model was established.Finite element analysis of the femur model was established,and three intertrochanteric fracture models,medial defect,lateral defect,and medial-lateral defects,were simulated.Displacement and stress distribution after fixation with a proximal femoral anti-rotation intramedullary nail(PFNA),integrated dual-screw fixation(ITN),PFNA+wire,PFNA+plate,and PFNA+wire+plate were compared during daily activities.RESULTS The maximum displacement and stress of PFNA and ITN were 3.51 mm/473 MPa and 2.80 mm/588 MPa for medial defects;2.55 mm/288 MPa and 2.10 mm/307 MPa for lateral defects;and 3.84 mm/653 MPa and 3.44 mm/641 MPa for mediallateral defects,respectively.For medial-lateral defects,reconstructing the medial side alone changed the maximum displacement and stress to 2.79 mm/515 MPa;reconstructing the lateral side changed them to 3.72 mm/608 MPa,when both sides were reconstructed,they changed to 2.42 mm/309 MPa.CONCLUSION For medial defects,intramedullary fixation would allow early low-intensity rehabilitation exercise,and ITN rather than PFNA reduces the risk of varus and cut-out;for lateral wall defects or weakness,intram-edullary fixation allows higher-intensity rehabilitation exercise,and ITN reduces the risk of varus.For both medial and lateral defects,intramedullary fixation alone will not allow early functional exercise,but locating lateral or medial reconstruction will.For defects in both the inner and outer sides,if reconstruction cannot be completed,ITN is more stable.
文摘Background: To avoid the irritation of tendons and soft tissues as well as hardware-related problems, we designed an intramedullary fixation with bioabsorbable rods for the treatment of the metacarpal shaft fractures. Methods: Five patients with nine shaft fractures of the fourth and fifth metacarpi were treated with intramedullary absorbable implants and followed up with an average of 4.2 months postoperatively. Results: At final follow-up, all patients achieved fracture union with no signs of inflammatory or subcutaneous effusion. There was no shortening, angulatory, or rotatory deformity. There was almost full active extension range of motion (ROM) of the metacarpophalangeal joints while the active flexion ROM of these joints was 80.7 ± 9.6°. hand was 94.0 ± 9.6%. X-rays showed that the arch of the second Compared with the contralateral hand, the grip strength of the injured to fifth metacarpal heads was smooth. There were no intramedullary lytic changes and soft tissue swellings. Conclusion: The intramedullary absorbable implants are a safe, simple, and practical treatment for fourth and filth metacarpal fractures with good early clinical outcomes and no significant complications.
文摘Objective To provide morphological reference for the designing of the intramedullary nail fixation which suitable for Chinese by investigating the morphological characteristics of tibial medullary cavity. Methods The morphological parameters of the 113 normal adult tibiale were measured on the X-ray photographs with the image analysis software. Results The total lengths of tibial medullary cavities were 299.49±11.03 mm(male) and 274.60± 6.77 mm(female), and the lengths of the narrow part were 66.36±3.90 mm(male) and 51.57±3.92mm(female). The end-points of narrow part were about 29.9 mm(male) and 26.09 mm(female)below the midpoints of medullary cavities. The radians of the longitudinal axes of medullary cavities were 2.53±1.27°(male) and 2.57±1.16°(female). The proximal opening K were 9.47±2.71(male) and 8.59±2.46(female). The distal opening K were 8.21± 2.93(male)and 7.65±2.87(female). Conclusion The morphology of tibial medullary cavity, the characteristic variety of radian and the opening K were very important references for designing the Chinese intramedullary nail fixation.
基金Loma Linda Veterans Association for Research and EducationGrant/Award Number Seed Grant(to CR)+2 种基金US Department of Veterans AffairsGrant/Award Number Merit Review Award#5 I01 BX002519-04(to CR)Senior Research Career Scientist Award(to SM)。
文摘Objective: To better characterize nonunion endochondral bone healing and evaluate novel therapeutic approaches for critical size defect healing in clinically challenging bone repair, a segmental defect model of bone injury was adapted from the threepoint bending closed fracture technique in the murine femur.Methods: The mouse femur was surgically stabilized with an intramedullary threaded rod with plastic spacers and the defect adjusted to different sizes. Healing of the different defects was analyzed by radiology and histology to 8 weeks postsurgery. To determine whether this model was effective for evaluating the benefits of molecular therapy, BMP-2 was applied to the defect and healing then examined.Results: Intramedullary spacers were effective in maintaining the defect. Callus bone formation was initiated but was arrested at defect sizes of 2.5 mm and above, with no more progress in callus bone development evident to 8 weeks healing. Cartilage development in a critical size defect attenuated very early in healing without bone development, in contrast to the closed femur fracture healing, where callus cartilage was replaced by bone. BMP-2 therapy promoted osteogenesis of the resident cells of the defect, but there was no further callus development to indicate that healing to pre-surgery bone structure was successful.Conclusions: This segmental defect adaptation of the closed femur fracture model of murine bone repair severely impairs callus development and bone healing, reflecting a challenging bone injury. It is adjustable and can be compared to the closed fracture model to ascertain healing deficiencies and the efficacy of therapeutic approaches.
文摘Coronal shear fractures of the femoral neck (CSFF) are the most challenging to treat among proximal femur fractures, directly affecting the life expectancy of patients with osteoporosis. However, an adequate osteosynthesis method has not been elucidated yet. This study investigated the displacement direction of the femoral head fragment and its effect on the bone using finite element method. A finite element model for CSFF was developed from CT image data of a patient with osteoporosis using Mechanical Finder (ver. 11). Subsequently, finite element analyses were performed on six osteosynthesis models under maximum load applied during walking. The compressive stresses, tensile stresses, and compressive strains of each model were examined. The results suggested that the compressive and tensile stress distributions were concentrated on the anterior side of the femoral neck. Compressive strain distribution in the femoral head and neck was concentrated in four areas: at the tip of the blade or lag screw, the anteroinferior side of the blade or lag screw near the fracture site, and the upper right and lower left near the junction of the blade or lag screw and nail. Thus, the distribution of both these stresses revealed that the femoral head fragment was prone to anterior and inferior displacement. Distribution of compressive strains revealed the direction of the stress exerted by the osteosynthetic implant on the bone. The same results were observed in all osteosynthetic implants;thus, the findings could lay the foundation for developing methods for placing osteosynthetic implants less prone to displacement and the osteosynthetic implants themselves. In particular, the study provides insight into the optimal treatment of CSFF.