Wang Hongsheng, Gee Albert O, Hutchinson Ian D, Stoner Kirsten, Warren Russell F, Chen Tony O, Maher Suzanne A
Hospital for Special Surgery, New York, New York, USA.
Hospital for Special Surgery, New York, New York, USA
Am J Sports Med. 2014 Jul;42(7):1682-9. doi: 10.1177/0363546514530867. Epub 2014 Apr 28.
Meniscus allograft transplantation (MAT) is primarily undertaken to relieve the symptoms associated with meniscal deficiencies. However, its ability to restore normal knee joint contact mechanics under physiological loads is still unclear.
To quantify the dynamic contact mechanics associated with 2 commonly used fixation techniques in MAT of the medial compartment: transosseous suture fixation via bone plugs and suture-only fixation at the horns.
Controlled laboratory study.
Physiological loads to mimic gait were applied across 7 human cadaveric knees on a simulator. A sensor placed on the medial tibial plateau recorded dynamic contact stresses under the following conditions: (1) intact meniscus, (2) MAT using transosseous suture fixation via bone plugs at the anterior and posterior horns, (3) MAT using suture-only fixation, and (4) total medial meniscectomy. A "remove-replace" procedure was performed to place the same autograft for both MAT conditions to minimize the variability in graft size, geometry, and material property and to isolate the effects of the fixation technique. Contact stress, contact area, and weighted center of contact stress (WCoCS) were quantified on the medial plateau throughout the stance phase.
Knee joint contact mechanics were sensitive to the meniscal condition primarily during the first half of the gait cycle. After meniscectomy, the mean peak contact stress increased from 4.2 ± 1.2 MPa to 6.2 ± 1.0 MPa (P = .04), and the mean contact area decreased from 546 ± 132 mm2 to 192 ± 122 mm2 (P = .01) compared with the intact meniscus during early stance (14% of the gait cycle). After MAT, the mean contact stress significantly decreased with bone plug fixation (5.0 ± 0.7 MPa) but not with suture-only fixation (5.9 ± 0.7 MPa). Both fixation techniques partially restored the contact area, but bone plug fixation restored it closer to the intact condition. The location of WCoCS in the central cartilage region (not covered by the meniscus) shifted peripherally throughout the stance phase. Bone plug fixation exhibited correction to this peripheral offset, but suture-only fixation did not.
Under dynamic loading, transosseous fixation at the meniscal horns provides superior load distribution at the involved knee compartment after meniscal transplantation compared with suture-only fixation. Particular attention should be directed to the ability of medial MAT to function during the early stance phase.
Transosseous fixation via bone plugs provides superior load distribution of a transplanted meniscal allograft compared with suture fixation alone at time zero.
同种异体半月板移植(MAT)主要用于缓解与半月板缺损相关的症状。然而,其在生理负荷下恢复正常膝关节接触力学的能力仍不明确。
量化内侧间室MAT中两种常用固定技术相关的动态接触力学:通过骨栓的经骨缝合法固定和仅在角部进行缝合法固定。
对照实验室研究。
在模拟器上对7具人类尸体膝关节施加模拟步态的生理负荷。放置在内侧胫骨平台上的传感器记录以下情况下的动态接触应力:(1)半月板完整,(2)通过前后角的骨栓采用经骨缝合法固定进行MAT,(3)采用仅缝合法固定进行MAT,(4)内侧半月板全切除术。对两种MAT情况均采用“移除-替换”程序放置相同的同种异体移植物,以尽量减少移植物大小、几何形状和材料特性的变异性,并分离固定技术的影响。在整个站立期对内侧面的接触应力、接触面积和接触应力加权中心(WCoCS)进行量化。
膝关节接触力学主要在步态周期的前半段对半月板状况敏感。半月板切除术后,与早期站立(步态周期的14%)时的完整半月板相比,平均峰值接触应力从4.2±1.2MPa增加到6.2±1.0MPa(P = 0.04),平均接触面积从546±132mm²减少到192±122mm²(P = 0.01)。MAT后,采用骨栓固定时平均接触应力显著降低(5.0±0.7MPa),而仅缝合法固定时则未降低(5.9±0.7MPa)。两种固定技术均部分恢复了接触面积,但骨栓固定使其恢复得更接近完整状态。在整个站立期,WCoCS在中央软骨区域(未被半月板覆盖)的位置向周边移动。骨栓固定对这种周边偏移有矫正作用,而仅缝合法固定则没有。
在动态负荷下,与仅缝合法固定相比,半月板角部的经骨固定在半月板移植后为受累膝关节间室提供了更好的负荷分布。应特别关注内侧MAT在早期站立期的功能能力。
与仅缝合法固定相比,通过骨栓的经骨固定在零时为移植的同种异体半月板提供了更好的负荷分布。