Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA; Department of Orthopedic Surgery, College of Medicine, Dongguk University, Gyeongju, Republic of Korea.
Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA.
J Shoulder Elbow Surg. 2019 Aug;28(8):1449-1456. doi: 10.1016/j.jse.2019.02.021. Epub 2019 May 7.
Ulnar or humeral component stem fractures after total elbow arthroplasty (TEA) are serious complications. We hypothesized that TEA stem component fractures are fatigue fractures that result from periarticular osteolysis caused by bushing wear, which leads to a region of unsupported stem adjacent to a region where the stem is well-fixed.
A review of 2637 primary and revision TEA cases from 1972 to 2016 revealed that 47 operations in 46 patients were complicated by or performed to deal with component stem fractures. Bushing wear was graded according to percentage loss of polyethylene thickness and metal wear.
In the 39 cases in which bushing wear was able to be quantitated, it was severe in 34, moderate in 2, and mild in 3. Radiographs at final follow-up were available in 47 cases. All 47 cases showed evidence of periarticular osteolysis, which was in zone 1 in 17, in zones 1 and 2 in 29, and diffuse in 1. The length of the well-fixed stem, expressed as a percentage of total stem length, averaged 63% (range, 29%-86%). Stem fractures most often (27 of 47 cases) occurred at the junction between the well-fixed stem and unsupported stem. The median distance between the site of stem fracture and the unsupported-well-fixed stem junction was 0 mm (interquartile range, 0-5 mm).
On the basis of our findings, a component stem fracture after TEA seems to occur by fatigue failure at or near the junction between an unsupported stem and well-fixed stem. This area of unsupported stem occurs as a result of osteolysis caused by bushing wear. The solution for component fractures requires a solution for bushing wear.
全肘关节置换术后（TEA）发生尺骨或肱骨组件干骨折是严重的并发症。我们假设 TEA 干组件骨折是疲劳骨折，是由衬套磨损引起的关节周围骨溶解导致的，这导致了一个无支撑干的区域，紧邻一个干固定良好的区域。
回顾 1972 年至 2016 年的 2637 例初次和翻修 TEA 病例，发现 46 例 47 例手术中存在或发生了组件干骨折并发症。根据聚乙烯厚度损失的百分比和金属磨损对衬套磨损进行分级。
在能够定量衬套磨损的 39 例中，严重磨损 34 例，中度磨损 2 例，轻度磨损 3 例。47 例在最终随访时拍摄了 X 线片。47 例均显示关节周围骨溶解的证据，其中 17 例位于 1 区，29 例位于 1 区和 2 区，1 例弥漫性。固定良好的干长度，以总干长度的百分比表示，平均为 63%（范围 29%-86%）。干骨折最常见（47 例中有 27 例）发生在固定良好的干和无支撑干的交界处。干骨折部位与无支撑-固定良好干交界处之间的中位数距离为 0 毫米（四分位距，0-5 毫米）。
根据我们的发现，TEA 后发生的组件干骨折似乎是在无支撑干和固定良好的干交界处或附近发生疲劳破坏。无支撑干的这个区域是由衬套磨损引起的骨溶解导致的。解决组件骨折的问题需要解决衬套磨损的问题。
