Hope Orthopedics of Oregon, Salem, OR.
Department of Orthopaedic Surgery, Rutgers - New Jersey Medical School, Newark, NJ.
Injury. 2021 Apr;52(4):686-691. doi: 10.1016/j.injury.2020.11.040. Epub 2020 Nov 15.
The purpose of this study was to compare the biomechanical attributes of patella fracture fixation with either anterior plating utilizing two parallel, longitudinal 2.0 mm plates technique versus a cannulated screw tension band technique.
Five matched pairs (ten specimens) of fresh frozen cadavers were utilized. A transverse patella fracture (OTA 34C1.1) was fixed using either two 4.0 mm cannulated screw anterior tension band (CATB) or with two 2.0 mm stainless steel non-locking plates along the anterior cortex secured with 2.4 mm cortical screws traversing the fracture site. Specimens underwent 1000 cycles of simulated active knee range of motion before load to failure destructive testing.
During cyclic loading there were no failures in the plate fixation group, and 2 out of 5 specimens catastrophically failed in the CATB group (p = 0.22). Average fracture displacement at the end of fatigue testing was 0.96 mm in the plate fixation group and 2.72 mm in the CATB group (p = 0.18). The specimens that withstood cyclic testing underwent a destructive load. Mean load to failure for the plate fixation specimens was 1286 N, which was not significantly different from the CATB group mean of 1175 N (p = 0.48). The mechanism of failure in the plate fixation cohort was uniformly via a secondary vertical patella fracture around the plates in all five specimens. In the CATB group, the mechanism of failure was via wire elongation and backing out of the screws.
Patella fixation with anterior plating technique statistically performed equivalent to cannulated screw anterior tension band in ultimate load to failure strength and fatigue endurance under cyclical loading. No failures were observed cyclic simulated active range of motion in the anterior plate group. There was a trend towards improved fatigue endurance in the plate fixation group, however this did not reach statistical significance. We believe plate fixation technique represents a low-profile implant option for treatment of transverse patella fractures, which may allow for early active range of motion, and these data support biomechanical equivalency to standard of care.
本研究旨在比较使用 2.0 毫米平行纵向双板技术的前侧钢板固定与使用空心螺钉张力带技术治疗髌骨骨折的生物力学特性。
使用 5 对（10 个标本）新鲜冷冻尸体标本。采用横向髌骨骨折（OTA 34C1.1），使用 4.0 毫米空心螺钉前侧张力带（CATB）或沿前皮质固定的 2.0 毫米不锈钢非锁定板固定，用 2.4 毫米皮质螺钉穿过骨折部位。标本在进行失效性破坏性测试前先进行 1000 次模拟主动膝关节活动范围的循环加载。
在循环加载过程中，钢板固定组无失败病例，而 CATB 组有 2 例（5 例中的 2 例）灾难性失败（p=0.22）。在疲劳测试结束时，钢板固定组的骨折位移平均为 0.96 毫米，而 CATB 组为 2.72 毫米（p=0.18）。经受循环测试的标本进行了破坏性载荷测试。钢板固定标本的失效载荷平均值为 1286 N，与 CATB 组的 1175 N 平均值无显著差异（p=0.48）。钢板固定组的失效机制均为在所有 5 个标本中，钢板周围出现二次垂直髌骨骨折。在 CATB 组，失效机制为钢丝伸长和螺钉退出。
在前侧钢板固定技术下，髌骨骨折的固定在最终失效载荷和循环加载下的疲劳耐力方面与空心螺钉前侧张力带技术统计学等效。在前侧钢板组，未观察到循环模拟主动活动范围内的失效。钢板固定组的疲劳耐力有改善趋势，但未达到统计学意义。我们认为钢板固定技术是治疗横向髌骨骨折的低轮廓植入物选择，可能允许早期主动活动范围，这些数据支持与标准治疗相比具有生物力学等效性。
