Ettinger Max, Zoch Johanna Marie, Becher Christoph, Hurschler Christof, Stukenborg-Colsman Christina, Claassen Leif, Ostermeier Sven, Calliess Tilman
Department for Orthopaedic Surgery, Hannover Medical School, Anna-von_Borries-Str. 1-7, 30625, Hannover, Germany,
Arch Orthop Trauma Surg. 2015 Jun;135(6):871-7. doi: 10.1007/s00402-015-2214-x. Epub 2015 Apr 16.
When performing unicondylar knee arthroplasty (UKA), the surgeon can choose between two fundamentally different designs: a mobile-bearing (MB) inlay with high conformity, or a low-conformity, fixed bearing (FB) inlay. There is an ongoing debate in the orthopaedic community about which design is superior. To date, there have been no comparative biomechanical studies regarding each system's effects on the quadriceps force and the medial contact pressure. The purpose of this study was to investigate these alterations in vitro before and after UKA with two prosthesis systems, representing the MB and FB designs.
FB and MB unicondylar knee prosthesis designs were tested in sequence under isokinetic extension in an in vitro simulator. In each case, the required quadriceps extension force was determined before and after implantation of a medial UKA. Furthermore, the tibiofemoral contact pressures were evaluated for both prosthesis designs.
The quadriceps force maximum was achieved at 106° and 104° of flexion with the FB and MB designs, respectively. Implantation of the FB UKA resulted in a significant increase in the necessary maximum quadriceps force (p = 0.006). In addition, implantation of the MB UKA resulted in a significantly higher extension force (p = 0.03). The difference between the two groups was statistically significant in deep flexion (p = 0.03), with higher forces in MB UKA.
The MB design showed significantly increased quadriceps extension force compared with the FB inlay in deep flexion. Although the FB design showed higher maximum peak pressures concentrated on a smaller area, the pressure introduction in deep flexion was lower, compared to MB inserts.
在进行单髁膝关节置换术（UKA）时，外科医生可以在两种根本不同的设计之间进行选择：高贴合度的活动平台（MB）嵌体，或低贴合度的固定平台（FB）嵌体。骨科界对于哪种设计更优越一直存在争论。迄今为止，尚未有关于每种系统对股四头肌力量和内侧接触压力影响的比较性生物力学研究。本研究的目的是在体外研究使用代表MB和FB设计的两种假体系统进行UKA前后的这些变化。
在体外模拟器中，对FB和MB单髁膝关节假体设计进行等速伸展测试。在每种情况下，在植入内侧UKA之前和之后确定所需的股四头肌伸展力。此外，评估了两种假体设计的胫股接触压力。
FB和MB设计分别在屈曲106°和104°时达到股四头肌力量最大值。植入FB UKA导致所需的最大股四头肌力量显著增加（p = 0.006）。此外，植入MB UKA导致伸展力显著更高（p = 0.03）。两组之间在深度屈曲时差异具有统计学意义（p = 0.03），MB UKA的力量更高。
在深度屈曲时，与FB嵌体相比，MB设计显示股四头肌伸展力显著增加。尽管FB设计显示更高的最大峰值压力集中在较小区域，但与MB嵌体相比，深度屈曲时的压力传导较低。
