Department of Orthopaedic Surgery, Maine Medical Center, Falmouth, ME.
Department of Orthopaedic Surgery, OrthoCarolina, Charlotte, NC.
J Arthroplasty. 2020 Feb;35(2):508-512. doi: 10.1016/j.arth.2019.09.028. Epub 2019 Sep 26.
Revision of monoblock metal-on-metal (MoM) total hip arthroplasty (THA) is associated with high complication rates. Limited revision by conversion to a dual mobility (DM) without acetabular component extraction may mitigate these complications. However, the concern for polyethylene wear and osteolysis remains unsettled. This study investigates the results of DM conversion of monoblock MoM THA compared to formal acetabular revision.
One hundred forty-three revisions of monoblock MoM THA were reviewed. Twenty-nine were revisions to a DM construct, and 114 were complete revisions of the acetabular component. Mean patient age was 61, 54% were women. Components used, acetabular cup position, radiographic outcomes, serum metal ion levels, and HOOS Jr clinical outcome scores were investigated.
At 3.9 years of follow-up (range 2-5), there were 2 revisions (6.9%) in the DM cohort, 1 for instability and another for periprosthetic fracture. Among the formal acetabular revision group there was a 20% major complication rate (23/114) and 16% underwent revision surgery (18/114) for aseptic loosening of the acetabular component (6%), deep infection (6%), dislocation (4%), acetabular fracture (3%), or delayed wound healing (6%). In the DM cohort, there were no radiographic signs of aseptic loosening, component migration, or polyethylene wear. One DM patient had a small posterior metadiaphyseal femur lesion that will require close monitoring. There were no other radiographic signs of osteolysis. There were no clinically significant elevations of serum metal ion levels. HOOS Jr scores were favorable.
Limited revision with conversion to DM is a viable treatment option for failed monoblock MoM THA with lower complication rates than formal revision. Limited revision to DM appears to be a safe option for revision of monoblock MoM THA with a cup in good position and an internal geometry free of sharp edges or articular surface damage. Longer follow-up is needed to demonstrate any potential wear implications of these articulations.
翻修一体式金属对金属（MoM）全髋关节置换术（THA）与高并发症发生率相关。通过不取出髋臼部件而转换为双动（DM）来有限翻修可能会减轻这些并发症。然而，对于聚乙烯磨损和骨溶解的担忧仍未解决。本研究比较了一体式 MoM THA 的 DM 转换与正式髋臼翻修的结果。
对 143 例一体式 MoM THA 的翻修进行了回顾。其中 29 例为 DM 结构翻修，114 例为髋臼部件的完全翻修。平均患者年龄为 61 岁，54%为女性。研究了使用的组件、髋臼杯位置、影像学结果、血清金属离子水平和 HOOS Jr 临床结果评分。
在 3.9 年的随访期（范围 2-5 年）中，DM 组有 2 例（6.9%）翻修，1 例为不稳定，另 1 例为假体周围骨折。在正式髋臼翻修组中，有 20%（23/114）发生重大并发症，16%（18/114）因髋臼部件无菌性松动（6%）、深部感染（6%）、脱位（4%）、髋臼骨折（3%）或延迟伤口愈合（6%）而行翻修手术。在 DM 组中，没有无菌性松动、组件迁移或聚乙烯磨损的影像学迹象。1 例 DM 患者出现股骨小后侧骨干病变，需要密切监测。没有其他影像学骨溶解的迹象。没有明显的血清金属离子水平升高。HOOS Jr 评分良好。
对于一体式 MoM THA 的失败，采用 DM 转换的有限翻修是一种可行的治疗选择，其并发症发生率低于正式翻修。对于髋臼位置良好、内部几何形状无锋利边缘或关节面损伤的一体式 MoM THA，采用 DM 进行有限翻修似乎是一种安全的选择。需要更长时间的随访来证明这些关节的任何潜在磨损影响。
