Recent advances in vascular tissue engineering have enabled a paradigm shift from ensuring short-term graft survival to focusing on long-term stability and growth potential. We present the first experimental-computational study of a tissue-engineered vascular graft (TEVG) effectively over the full lifespan of the recipient. We show that grafts implanted within the venous circulation of mice remained patent over 2 years without thrombus, stenosis, or aneurysmal dilatation. Moreover, the gross appearance and mechanical properties of the grafts evolved to be similar to the host vein within 24 weeks, with mean neovessel geometry and properties remaining unchanged thereafter despite a continued turnover of extracellular matrix. Biomechanical diversity manifested after 24 weeks, however, via two subsets of grafts despite all procedures being the same. Computational modeling and associated immunohistological analyses suggested that this diversity likely resulted from a differential ratio of collagen types I and III, with lower I to III ratios promoting grafts having a compliance similar to the native vein. We submit that TEVGs can exhibit the desired long-term mechanobiological stability; hence, we must now focus on evaluating growth potential and optimizing scaffold properties to achieve compliance matching throughout neovessel development.
➣ Underdetection and undertreatment of transverse plane malalignment of the tibia and femur result from challenges with accuracy and reliability of both physical examination and imaging.➣ Excessive femoral and tibial torsion both impair joint moment generation, with potential adverse effects on joint health directly as well as indirectly as a result of gait compensation.➣ Static computed tomography measurements of rotational alignment are limited by variable reference axes, expense, radiation exposure, and inability to measure dynamic compensation, and to date they have not been applicable intraoperatively.➣ Kinematics derived from functional modeling in 3-dimensional (3D) gait analysis provide subject-specific data and can detect not only static but also functional alignment.➣ The use of 3D data generated by EOS radiography holds promise for assessing biplanar limb alignment.
Background:For stable intertrochanteric hip fractures, treatment commonly involves the use of a sliding hip screw. Intertrochanteric hip fractures are increasingly common as the population ages and lives longer. More than 250,000 hip fractures occur per year in the United States1. The mortality rate within the first year following operative treatment ranges from 14% to 27.3%2,3. Early surgical repair within 48 hours of injury is associated with a lower risk of mortality2,4,5. The goals of surgical treatment are restoration of coronal plane alignment without varus angulation and early patient mobilization.Description:The sliding hip screw procedure can be divided into (1) preoperative planning; (2) patient positioning; (3) C-arm setup; (4) closed reduction of fracture; (5) sterile preparation and draping; (6) lateral hip approach; (7) guide pin insertion; (8) triple-reaming the proximal aspect of the femur; (9) sliding hip screw insertion into the femoral neck and head; (10) side plate insertion, engaging the sliding hip screw, and fixation to the femur; (11) lag compression screw insertion (if appropriate); and (12) final fluoroscopic images and wound closure.Alternatives:Intertrochanteric hip fractures must be surgically treated to avoid morbidity and increased risk of mortality. Nonoperative treatment is occasionally indicated in nonambulatory patients or those with high perioperative risk. If treated surgically, a common alternative implant option includes the intramedullary nail. Finally, for severely comminuted fractures or failed internal fixation, total hip arthroplasty may be necessary.Rationale:Sliding hip screws are as effective as intramedullary nails and often less costly6. In general, the quality of fracture reduction is more critical than the choice of implant7. A prospective study found no significant difference in walking ability with either sliding hip screws or intramedullary nails for stable intertrochanteric fractures8.Expected Outcomes:By 6 months, the majority of fractures will have healed; according to a prospective randomized study, 91% of stable fractures and 85% of unstable fractures had achieved radiographic union by that time9. Another study showed radiographically healed fractures in all 106 patients treated with sliding hip screws at median follow-up of 13.6 months8.Important Tips:Watch out for comminution of the greater or lesser trochanter, which may require supplemental fixation.Prior to completely reflecting the vastus lateralis muscle, control the bleeding from any perforators with use of 2-0 silk ties. This prevents recurrent bleeding, which often occurs if only cautery is utilized to coagulate these vessels.Utilize a 4.5-mm drill hole in the lateral cortex of the femur in order to allow for minor adjustments of the anterior femoral neck guide pin; otherwise, the pin will be held tightly and continue to be bound in the same direction by the lateral cortex on repeated attempts.If the guide pin is inadvertently withdrawn along with the reamer after reaming, a lag screw may be plac...
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