Department of Orthopaedic Surgery, University of California, Los Angeles, Los Angeles, California, USA.
Bone Joint J. 2019 Jun;101-B(6):724-731. doi: 10.1302/0301-620X.101B6.BJJ-2018-0993.R1.
Aseptic loosening is a major cause of failure in cemented endoprosthetic reconstructions. This paper presents the long-term outcomes of a custom-designed cross-pin fixation construct designed to minimize rotational stress and subsequent aseptic loosening in selected patients. The paper will also examine the long-term survivorship and modes of failure when using this technique.
A review of 658 consecutive, prospectively collected cemented endoprosthetic reconstructions for oncological diagnoses at a single centre between 1980 and 2017 was performed. A total of 51 patients were identified with 56 endoprosthetic implants with cross-pin fixation, 21 of which were implanted following primary resection of tumour. Locations included distal femoral (n = 36), proximal femoral (n = 7), intercalary (n = 6), proximal humeral (n = 3), proximal tibial (n = 3), and distal humeral (n = 1).
The median follow-up was 132 months (interquartile range (IQR) 44 to 189). In all, 20 stems required revision: eight for infection, five for structural failure, five for aseptic loosening, and two for tumour progression. Mechanical survivorship at five, ten, and 15 years was 84%, 78%, and 78%, respectively. Mechanical failure rate varied by location, with no mechanical failures of proximal femoral constructs and distal femoral survivorship of 82%, 77%, and 77% at five, ten, and 15 years. The survivorship of primary constructs at five years was 74%, with no failure after 40 months, while the survivorship for revision constructs was 89%, 80%, and 80% at five, ten, and 15 years.
The rate of mechanical survivorship in our series is similar to those reported for other methods of reconstruction for short diaphyseal segments, such as compressive osseointegration. The mechanical failure rate differed by location, while there was no substantial difference in long-term survival between primary and revision reconstructions. Overall, custom cross-pin fixation is a viable option for endoprosthetic reconstruction of short metaphyseal segments with an acceptable rate of mechanical failure. Cite this article: 2019;101-B:724-731.
无菌性松动是骨水泥固定假体重建失败的主要原因。本文介绍了一种定制的交叉销固定结构的长期结果，该结构旨在最大限度地减少选定患者中的旋转应力和随后的无菌性松动。本文还将研究使用该技术时的长期存活率和失效模式。
对 1980 年至 2017 年间在一家中心进行的连续、前瞻性收集的 658 例肿瘤诊断的骨水泥固定假体重建进行了回顾。共发现 51 例患者，56 例假体植入物采用交叉销固定，其中 21 例在肿瘤切除后初次植入。部位包括股骨远端（n = 36）、股骨近端（n = 7）、间插（n = 6）、肱骨近端（n = 3）、胫骨近端（n = 3）和肱骨远端（n = 1）。
中位随访时间为 132 个月（四分位距（IQR）44 至 189）。总共需要翻修 20 个假体：8 个因感染，5 个因结构性失败，5 个因无菌性松动，2 个因肿瘤进展。5 年、10 年和 15 年的机械存活率分别为 84%、78%和 78%。机械故障率因部位而异，股骨近端假体无机械故障，股骨远端 5 年、10 年和 15 年的存活率分别为 82%、77%和 77%。5 年时初次重建的存活率为 74%，40 个月后无失败，而翻修重建的存活率为 5 年、10 年和 15 年分别为 89%、80%和 80%。
我们的研究中机械存活率与其他用于短骨干重建的方法（如压缩骨整合）相似。故障率因部位而异，而初次重建和翻修重建的长期存活率之间没有显著差异。总体而言，定制交叉销固定是一种可行的短骨干假体重建选择，其机械失败率可接受。
