Department of Orthopaedic Surgery, Department of Orthopaedic Surgery, Sengkang General Hospital, 110 Sengkang East Way, 544886, Singapore.
School of Mechanical & Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
Injury. 2022 Dec;53(12):3894-3898. doi: 10.1016/j.injury.2022.09.039. Epub 2022 Sep 28.
A large proportion of hip fractures involve inter-trochanteric fractures which are managed by cephalomedullary nails. There is ongoing debate about the advantages and disadvantages of locked versus unlocked long cephalomedullary femoral nails in the treatment of intertrochanteric fractures. The objectives of our study are to evaluate the biomechanical effects of a distal interlocking bolt on the type of peri-implant fractures in a healed intertrochanteric fracture with long cephalomedullary nail fixation.
20 femoral sawbone specimens were prepared with the TFN-ADVANCED Proximal Femoral Nailing System (TFNA) and divided into 2 groups: locked and unlocked. The specimens were subjected to axial loading force until failure. Compressive forces, strain and fracture patterns were compared between the 2 groups.
There was no significant difference in the mean load to failure of the unlocked specimens compared to locked specimens. However, there was significant difference in the mean compressive stress at the time of failure with the unlocked specimen (1.79±0.17 MPa) compared to the locked group (1.92±0.05 MPa) (p < 0.05). Video review analysis showed unlocked specimens consistently having basi-cervical type peri-implant fractures while locked specimens showed complex, compound fractures of the head-neck region with 2 or more fracture propagation points.
Distal-locked long cephalomedullary nails in a healed intertrochanteric fracture model are able to tolerate higher compressive stress at the point of failure but demonstrate more complex peri-implant fracture patterns in the femoral head-neck region as compared to unlocked specimens.
很大一部分髋部骨折涉及股骨转子间骨折，这些骨折采用股骨近端髓内钉治疗。在锁定与非锁定长髓内钉治疗转子间骨折的优缺点方面存在持续的争论。我们的研究目的是评估远端锁定螺栓对愈合的股骨转子间骨折采用长髓内钉固定后，种植体周围骨折类型的生物力学影响。
使用 TFN-ADVANCED 股骨近端髓内钉系统（TFNA）制备 20 个股骨标本，并分为锁定组和非锁定组。对标本进行轴向加载直至失效。比较两组的压缩力、应变和骨折模式。
与锁定组相比，非锁定组的失效平均载荷无显著差异。然而，在失效时的平均压缩应力方面，非锁定组（1.79±0.17 MPa）明显低于锁定组（1.92±0.05 MPa）（p<0.05）。视频回顾分析显示，非锁定组的标本始终存在基底干骺端型种植体周围骨折，而锁定组的标本显示出更复杂的头颈部复合骨折，有 2 个或更多的骨折传播点。
在愈合的股骨转子间骨折模型中，远端锁定的长髓内钉在失效时能够承受更高的压缩应力，但与非锁定标本相比，在股骨头颈区域显示出更复杂的种植体周围骨折模式。
