The American Journal of Sports Medicine ( IF 4.8 ) Pub Date : 2021-09-15 , DOI: 10.1177/03635465211041087 Amrit V Vinod 1 , Alex M Hollenberg 1 , Melissa A Kluczynski 1 , John M Marzo 1
Background:
Medial patellofemoral ligament (MPFL) reconstruction is an established operative procedure to restore medial restraining force in patients with patellar instability. In the setting of a shallow sulcus, it is unclear whether an isolated MPFL reconstruction is sufficient to restore patellofemoral stability.
Hypothesis:
Progressively increasing the sulcus angle would have an adverse effect on the ability of an MPFL reconstruction to restrain lateral patellar motion.
Study Design:
Controlled laboratory study.
Methods:
Seven fresh-frozen human cadaveric knees were harvested and prepared for experimentation. Each specimen was run through the following test conditions: native, lateral retinacular release, lateral retinacular repair, MPFL release, MPFL reconstruction, and MPFL reconstruction with trochlear flattening. Four 3-dimensional printed wedges (10°, 20°, 30°, and 40°) were created to insert beneath the native trochlea to raise the sulcus angle incrementally and simulate progressive trochlear flattening. For each test condition, the knee was positioned at 0°, 15°, 30°, and 45° of flexion, and the force required to displace the patella 1 cm laterally at 10 mm/s was measured. Group comparisons were made with repeated measures analysis of variance.
Results:
In the setting of an MPFL reconstruction, as the trochlear groove was incrementally flattened, the force required to laterally displace the patella progressively decreased. A 10° increase in the sulcus angle significantly reduced the force at 15° (P = .01) and 30° (P = .03) of knee flexion. The force required to laterally displace the patella was also significantly lower at all knee flexion angles after the addition of the 20°, 30°, and 40° wedges (P≤ .05). Specifically, a 20° increase in the sulcus angle reduced the force by 29% to 36%; a 30° increase, by 35% to 43%; and a 40° increase, by 40% to 47%.
Conclusion:
Despite an MPFL reconstruction, the force required to laterally displace the patella decreased as the sulcus angle was increased in our cadaveric model.
Clinical Relevance:
An isolated MPFL reconstruction may not be sufficient to restore patellar stability in the setting of a shallow or flat trochlea. Patients with an abnormal sulcus angle may have recurrent instability postoperatively if treated with an isolated MPFL reconstruction.
中文翻译:
在滑车变平的情况下,内侧髌股韧带重建克服髌骨外侧运动的能力:尸体生物力学研究
背景:
内侧髌股韧带 (MPFL) 重建是一种既定的手术程序,用于恢复髌骨不稳定患者的内侧约束力。在浅沟的情况下,尚不清楚单独的 MPFL 重建是否足以恢复髌股稳定性。
假设:
逐渐增加沟角会对 MPFL 重建抑制髌骨外侧运动的能力产生不利影响。
学习规划:
受控实验室研究。
方法:
收获了七个新鲜冷冻的人类尸体膝盖并准备用于实验。每个样本都经过以下测试条件:自然、外侧支持带释放、外侧支持带修复、MPFL 释放、MPFL 重建和带滑车扁平化的 MPFL 重建。创建了四个 3 维印刷楔形物(10°、20°、30° 和 40°),以插入天然滑车下方,以逐渐升高沟角并模拟逐渐变平的滑车。对于每个测试条件,膝关节处于屈曲 0°、15°、30° 和 45° 的位置,并测量以 10 mm/s 的速度将髌骨横向移位 1 cm 所需的力。组比较采用重复测量方差分析。
结果:
在 MPFL 重建的设置中,随着滑车槽逐渐变平,横向移位髌骨所需的力逐渐减小。沟角增加 10° 显着降低膝关节屈曲15° ( P = .01) 和 30° ( P = .03) 时的力。添加 20°、30° 和 40° 楔形后,在所有膝关节屈曲角度下,横向移位髌骨所需的力也显着降低 ( P ≤ .05)。具体来说,沟角增加 20° 使力减少 29% 到 36%;增加 30°,增加 35% 至 43%;增加 40°,增加 40% 到 47%。
结论:
尽管进行了 MPFL 重建,但随着我们尸体模型中沟角的增加,横向移位髌骨所需的力会降低。
临床相关性:
在浅或扁平滑车的情况下,孤立的 MPFL 重建可能不足以恢复髌骨稳定性。如果用孤立的 MPFL 重建治疗,患有异常沟角的患者可能会在术后复发性不稳定。