Puls Luise, Llano Lionel, Zderic Ivan, Gueorguiev Boyko, Stoffel Karl
AO Research Institute Davos, Clavadelerstrasse 8, Davos, 7270, Switzerland.
Department of Orthopedics and Traumatology, University Hospital Basel, Spitalstrasse 21, Basel, 4031, Switzerland.
J Orthop Surg Res. 2025 Apr 4;20(1):340. doi: 10.1186/s13018-025-05753-9.
Locked plating of femur fractures is associated with secondary peri-implant fractures which may be a result of stress concentrations at the proximal plate end region. The aim of this study was to investigate whether the strength of healed femoral bone-locking-compression-plate constructs can be increased by modifying the screw configurations and plate length to minimize the risks of peri-implant femur fractures.
The detached shaft of a variable angle condylar locking compression plate (VA-LCP Condylar Plate; Johnson & Johnson MedTech) was fixed to the proximal two-third of twenty-four intact artificial femurs in four different configurations (n = 6) distinguished by either using a short plate with cortical or locking screws whereby the most proximal screw was inserted in the femoral shaft 50 mm below the lesser trochanter, or using a long plate with either cortical or locking screws whereby the most proximal screw was positioned in the femoral neck. Simulating a situation after fracture healing, constructs were cyclically tested under progressively increased loading until catastrophic failure.
Long plates fixed with a cortical screws demonstrated the highest failure load (1091 N ± 142 N) which was significantly higher compared to long plates fixed with locking screws (888 N ± 80 N), short plates fixed with cortical screws (471 N ± 42 N), and short plates fixed with locking screws (450 N ± 19 N). In addition, whereas the locking screw construct with a long plate was associated with a significantly higher failure load compared to both short plate constructs, there were no significant differences between the latter two. The failure modes were predominantly characterized by neck screw pull-out in both long plate constructs and peri-implant bone fractures at the most proximal screw in both constructs with short plates. None of the specimens exhibited a femoral neck fracture.
The findings of this study performed on synthetic bones indicate that from a biomechanical perspective long plates that extend into the femoral neck sustained higher failure loads compared to short plates. In addition, long plates fixed with a cortical neck screw further enhanced the construct strength and reduced the risk of peri-implant fractures compared to the use of a locking neck screw. Therefore, this study supports the use of long locking plates combined with use of cortical neck screws, particularly in high-risk patients, such as those with severe osteoporosis.
股骨骨折的锁定钢板固定与继发的植入物周围骨折有关，这可能是近端钢板末端区域应力集中的结果。本研究的目的是调查通过改变螺钉配置和钢板长度以最小化植入物周围股骨骨折风险，能否提高愈合的股骨骨锁定加压钢板结构的强度。
将一个可变角度髁锁定加压钢板（VA-LCP髁钢板；强生医疗科技公司）的分离骨干以四种不同配置固定到24个完整人工股骨的近端三分之二处（n = 6），区别在于使用带皮质骨螺钉或锁定螺钉的短钢板，其中最近端螺钉插入股骨小转子下方50毫米处的股骨干中，或者使用带皮质骨螺钉或锁定螺钉的长钢板，其中最近端螺钉位于股骨颈中。模拟骨折愈合后的情况，对结构进行逐渐增加负荷的循环测试，直至发生灾难性失效。
用皮质骨螺钉固定的长钢板显示出最高的失效负荷（1091 N±142 N），与用锁定螺钉固定的长钢板（888 N±80 N）、用皮质骨螺钉固定的短钢板（471 N±42 N）和用锁定螺钉固定的短钢板（450 N±19 N）相比，显著更高。此外，虽然与两种短钢板结构相比，带长钢板的锁定螺钉结构的失效负荷显著更高，但后两者之间没有显著差异。失效模式主要表现为两种长钢板结构中的颈螺钉拔出以及两种短钢板结构中最近端螺钉处的植入物周围骨折。没有标本出现股骨颈骨折。
在合成骨上进行的本研究结果表明，从生物力学角度来看，延伸至股骨颈的长钢板与短钢板相比承受更高的失效负荷。此外，与使用锁定颈螺钉相比，用皮质骨颈螺钉固定的长钢板进一步增强了结构强度并降低了植入物周围骨折的风险。因此，本研究支持使用长锁定钢板并结合使用皮质骨颈螺钉，特别是在高危患者中，如严重骨质疏松症患者。
