Department of Orthopaedic Surgery, Chapel Allerton Hospital, Harehills Lane, Leeds, LS7 4SA, UK.
Arch Orthop Trauma Surg. 2013 Aug;133(8):1143-8. doi: 10.1007/s00402-013-1786-6. Epub 2013 Jun 9.
The aim of this study was to assess the long-term performance of a cemented total knee replacement utilising an All Polyethylene Tibial (APT) component and in addition to perform an engineering analysis of any failures to help refine surgical technique.
A total of 26 patients had a total knee replacement performed using a cemented Depuy Press Fit Condylar (PFC) APT component and a cruciate retaining femoral component. At final review all patients were assessed using The Knee Society Score together with radiographs. An engineering analysis simulated loading conditions of the implants that failed and these were compared with the performance of a modular metal-backed Tibial (MBT) component.
A total of 20 patients were reviewed at mean time of 116 months following surgery. Knee Society Knee Scores and Function Scores in this cohort were 84/100 and 58/100, respectively. Two patients required revision for tibial component failure. Pre-operatively both had valgus deformities and in each case the tibial tray had been lateralised leaving a gap on the medial side where the APT component had no rigid support. The engineering analysis demonstrated that the volume of highly strained cancellous bone was greater in the APT design compared with the MBT design when a model with a 3 mm medial gap was loaded. The stiffer MBT base plate acted more rigidly and shielded the stress applied to the proximal tibial cancellous bone.
The APT component demonstrated satisfactory clinical and radiographic performance at long-term follow up. Appropriate cortical support of the APT component is important. The implant should be used with a degree of caution in patients with severe deformities and osteoporosis.
本研究旨在评估使用全聚乙烯胫骨（APT）组件的骨水泥全膝关节置换的长期性能，并对任何失效进行工程分析，以帮助改进手术技术。
共有 26 例患者接受了使用骨水泥Depuy Press Fit Condylar（PFC）APT 组件和保留十字韧带的股骨组件的全膝关节置换术。在最终评估中，所有患者均使用膝关节协会评分（Knee Society Score）和 X 线片进行评估。工程分析模拟了失效植入物的加载条件，并将其与模块化金属背衬胫骨（MBT）组件的性能进行了比较。
共有 20 例患者在手术后平均 116 个月时进行了回顾。该队列的膝关节协会膝关节评分和功能评分分别为 84/100 和 58/100。有 2 例患者因胫骨组件失效而需要翻修。术前均有外翻畸形，在每种情况下，胫骨托板均已向外侧移位，留下内侧间隙，APT 组件在此处没有刚性支撑。工程分析表明，在加载具有 3mm 内侧间隙的模型时，APT 设计的高应变松质骨体积大于 MBT 设计。更硬的 MBT 基板更刚性地作用，并保护施加到胫骨近端松质骨的应力。
APT 组件在长期随访中表现出令人满意的临床和影像学性能。APT 组件的适当皮质支撑很重要。在严重畸形和骨质疏松症患者中应谨慎使用该植入物。
