Department of Orthopedics and Trauma Surgery, Medical Center, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.
Orthopaedic Department, Hannover Medical School, Hannover, Germany.
Knee Surg Sports Traumatol Arthrosc. 2019 Jul;27(7):2334-2344. doi: 10.1007/s00167-018-5194-x. Epub 2018 Oct 5.
Valgus high tibial osteotomy (HTO) and a recently introduced extra-articular absorber have been shown to efficiently unload the medial compartment of the knee. However, only little is known about the influence of these treatment modalities on biomechanics of the patellofemoral joint. The purpose of this study was to investigate and compare the impact of different HTO techniques and implantation of an extra-articular absorber on patellofemoral contact forces.
Fourteen fresh frozen cadaveric knees were tested in a specially designed knee simulator that allowed simulation of isokinetic flexion-extension motions under physiological loading. Mean contact pressure (ACP) and peak contact pressure (PCP) of the patellofemoral joint was measured continuously between 0° and 120° of knee flexion using a pressure sensitive film in the following conditions: native, after biplanar medial open-wedge HTO with 5° and 10° correction angle performing an ascending frontal osteotomy of the tibial tuberosity, and after implantation of an extra-articular absorber system (KineSpring®). Including a second testing cycle with a biplanar medial open-wedge HTO with 5° and 10° correction angle performing descending frontal osteotomy of the tibial tuberosity. Values after each procedure were compared to the corresponding values of the native knee.
Biplanar proximal osteotomy leaded to a significant increase of retropatellar compartment area contact pressure compared to the first untreated test cycle (Δ 0.04 ± 0.01 MPa, p = 0.04). Similar results were observed measuring peak contact pressure (Δ 1.41 ± 0.15 MPa, p = 0.03). With greater correction angle 5°, respectively, 10° peak and contact pressure increased accordingly. In contrast, the biplanar distal osteotomy group showed significant decrease of pressure values (p = 0.004). The extracapsular, extra-articular absorber had no significant influence on pressure levels in the patellofemoral joint.
HTO with a proximal biplanar osteotomy of the tuberositas tibia significantly increased patellofemoral pressure conditions depending on the correction angle. In contrast a distally directed biplanar osteotomy diminished these effects while implantation of an extracapsular, extra-articular absorber had no influence on the patellofemoral compartment at all. Consequently, patients with varus alignment with additional retropatellar chondropathia should be treated with a distally adverted osteotomy to avoid further undesirable pressure elevation in the patellofemoral joint.
外翻高位胫骨截骨术（HTO）和最近引入的关节外吸收器已被证明可有效地减轻膝关节内侧间室的负荷。然而，关于这些治疗方法对髌股关节生物力学的影响知之甚少。本研究的目的是研究和比较不同 HTO 技术和关节外吸收器植入对髌股关节接触力的影响。
在专门设计的膝关节模拟器中测试了 14 个新鲜冷冻的尸体膝关节，该模拟器允许在生理负荷下模拟等速屈伸运动。在 0°至 120°的膝关节屈伸过程中，使用压力敏感膜连续测量髌股关节的平均接触压力（ACP）和峰值接触压力（PCP），在以下情况下进行：正常、5°和 10°矫正角度的双平面内侧开放式楔形截骨术，胫骨结节的上升额状面截骨术，以及关节外吸收器系统（KineSpring®）的植入。包括第二次测试循环，在双平面内侧开放式楔形截骨术中，胫骨结节的下降额状面截骨术有 5°和 10°的矫正角度。每次手术后的值与相应的正常膝关节值进行比较。
双平面近端截骨术导致髌股关节后室接触压力明显增加，与第一次未治疗的测试周期相比（Δ 0.04±0.01 MPa，p=0.04）。测量峰值接触压力时也观察到类似的结果（Δ 1.41±0.15 MPa，p=0.03）。随着矫正角度的增加 5°，分别为 10°，峰值和接触压力相应增加。相比之下，双平面远端截骨组的压力值明显降低（p=0.004）。关节外、关节外吸收器对髌股关节的压力水平没有显著影响。
胫骨结节的双平面近端截骨术 HTO 显著增加了髌股关节的压力状况，这取决于矫正角度。相反，指向远端的双平面截骨术降低了这些效果，而关节外、关节外吸收器对髌股关节没有影响。因此，对于有内翻畸形且伴有髌股后软骨病的患者，应采用远端导向的截骨术来避免髌股关节进一步出现不必要的压力升高。
