Adult Reconstruction and Joint Replacement Service, Hospital for Special Surgery, New York, New York; The George Washington University School of Medicine, Washington, District of Columbia.
Adult Reconstruction and Joint Replacement Service, Hospital for Special Surgery, New York, New York.
J Arthroplasty. 2024 Sep;39(9S1):S203-S207. doi: 10.1016/j.arth.2024.06.018. Epub 2024 Jun 18.
Modular metaphyseal engaging (MME) femoral components in total hip arthroplasty (THA) allow optimized femoral length, offset, and anteversion and are useful in patients with unusual proximal femoral anatomy. Fretting, corrosion, and stem fractures above the modular sleeve are complications associated with these implants. The purpose of this study was to identify failure mechanisms of retrieved MME femoral components at our institution, identify all broken stem cases, and evaluate how often an extended trochanteric osteotomy (ETO) was required for removal.
All consecutively retrieved MME femoral components from September 2002 to May 2023 were reviewed. Patient demographics, procedure information, component specifications, indications for removal, and requirements for further revision surgery were reviewed. Descriptive statistics were calculated for variables of interest.
There were 131 retrieved MME components. The mean age at surgery was 59 years (range, 28 to 75), 49% were women, mean body mass index was 29.4 (range, 20.7 to 33.3), and mean American Society of Anesthesiologists score was 2.4 ± 0.5. There were 102 (78%) stems of 1 design (stem A), and 29 (22%) stems of a different design (stem B). Of 131 components, 10 (7.6%) failed secondary to stem fracture proximal to the modular sleeve. Four of 102 (4%) of stem A and 6 of 29 (21% of stem B) fractured. All broken stems required additional intervention for removal during revision THA, using an ETO (N = 9) or cortical window (N = 1) in which an intraoperative proximal femoral fracture occurred.
Broken MME stems present a challenge for orthopaedic surgeons during revision THA. When a stem fracture occurs above the ingrown sleeve, the distal splines may have osseous interdigitation into the clothespin. Thus, when revising a broken MME stem, an ETO should be performed, and the segment should be long enough to allow distal access.
在全髋关节置换术 (THA) 中，模块化干骺端嵌合 (MME) 股骨组件允许优化股骨长度、偏心距和前倾角，并且在具有异常股骨近端解剖结构的患者中非常有用。这些植入物的并发症包括微动、腐蚀和位于模块化套筒上方的柄断裂。本研究的目的是确定我们机构中取出的 MME 股骨组件的失效机制，确定所有柄断裂的病例，并评估需要多少次扩展转子截骨术 (ETO) 来取出。
回顾了 2002 年 9 月至 2023 年 5 月连续取出的所有 MME 股骨组件。回顾了患者人口统计学、手术信息、组件规格、取出指征和进一步翻修手术的要求。对感兴趣的变量进行了描述性统计分析。
共取出 131 个 MME 组件。手术时的平均年龄为 59 岁（范围 28 至 75 岁），49%为女性，平均体重指数为 29.4（范围 20.7 至 33.3），平均美国麻醉医师协会评分 2.4±0.5。102 个（78%）为 1 种设计的柄（柄 A），29 个（22%）为另一种设计的柄（柄 B）。在 131 个组件中，有 10 个（7.6%）因模块化套筒上方的柄断裂而失效。在 102 个柄 A 中，有 4 个（柄 A 的 4%）和 29 个柄 B 中，有 6 个（柄 B 的 21%）断裂。在所有需要进一步干预以移除的断裂 MME 柄中，在翻修 THA 时使用了 ETO（N=9）或皮质窗（N=1），其中术中发生了股骨近端骨折。
在翻修 THA 时，断裂的 MME 柄给骨科医生带来了挑战。当柄在套筒上方断裂时，远端齿可能与夹钳有骨质嵌合。因此，在修复断裂的 MME 柄时，应进行 ETO，并应足够长以允许远端进入。
