Mittelstaedt Hagen, Anderl Conrad, Ortmaier Reinhold, Johl Carsten, Krüger Thomas, Wallroth Karsten, Weigert Ulrich, Schagemann Jan C
UKSH Campus Lübeck, Klinik für Orthopädie und Unfallchirurgie Sektion Orthopädie, Ratzeburger Allee, Lübeck, Germany.
Ordensklinikum Linz, Krankenhaus der Barmherzigen Schwestern Linz GmbH, Seilerstätte, Linz, Austria.
J Orthop. 2023 Jul 23;43:93-100. doi: 10.1016/j.jor.2023.06.009. eCollection 2023 Sep.
Metaphyseal fixation of short stem THA allows for minimally invasive surgery, less bone removal, improved bone load transfer and reduced stress shielding. Short stems facilitate the anatomic restoration i.a. of leg length, femoroacetabular offset, and center of rotation. However, metaphyseal fixation might cause impaired primary and/or secondary stability resulting in an inherent tendency for early axial migration and aseptic loosening eventually. The objective of this study was to investigate the long-term outcome and migration pattern of a calcar-guided short stem.
In a prospective multicenter study, 213 patients (224 THAs) were enrolled. Patients were followed for up to 84 months postoperatively. Clinical outcome was assessed using the Harris Hip Score and the VAS for pain and satisfaction. Standardized and calibrated radiographs were screened i.a. for stress shielding and loosening. Einzel-Bild-Roentgen-Analyse - femoral component analysis (EBRA-FCA) was used to detect longitudinal subsidence.
At 7 year follow-up, n = 139/224 cases were available for analysis. All clinical parameters improved significantly (p < 0.001) and improvement persisted. There were no radiographic changes indicating stress shielding. EBRA-FCA revealed a mean subsidence of -1.44 mm followed by a stabilization. Weight >80 kg (p = 0.115), BMI <30 kg/m (p = 0.282), male gender (p = 0.246), and age <65 years (p = 0.304) seemed to be associated with a higher risk for migration. The cumulative revision rate was 2.23%. Revisions due to stem migration (0.89%) occurred early (mean time between index surgery and revision: 3.3 months).
If at all, there appears to be a pronounced initial subsidence, which stabilizes thereafter. Stem migration was rarely a compelling reason for failure or revision. Demographics do not seem to have a significant effect on migration pattern. The absence of radioluce lines, resorption or hypertrophy of the proximal femora support the hypothesis of a reduced stress shielding for metaphyseal anchoring short stems.
短柄全髋关节置换术（THA）的干骺端固定允许进行微创手术，减少骨量去除，改善骨负荷传递并减少应力遮挡。短柄有助于恢复下肢长度、股骨髋臼偏移和旋转中心等解剖结构。然而，干骺端固定可能会导致初始和/或二次稳定性受损，最终导致早期轴向移位和无菌性松动的内在倾向。本研究的目的是调查一种股骨距引导短柄的长期疗效和移位模式。
在一项前瞻性多中心研究中，纳入了213例患者（224例THA）。对患者进行术后长达84个月的随访。使用Harris髋关节评分以及疼痛和满意度视觉模拟评分（VAS）评估临床疗效。对标准化和校准的X线片进行筛查，以评估应力遮挡和松动情况。使用单张图像X线分析-股骨组件分析（EBRA-FCA）检测纵向下沉。
在7年随访时，有139/224例可供分析。所有临床参数均显著改善（p < 0.001）且改善持续存在。没有影像学改变表明存在应力遮挡。EBRA-FCA显示平均下沉1.4 mm，随后趋于稳定。体重>80 kg（p = 0.115）、体重指数（BMI）<30 kg/m²（p = 0.282）、男性（p = 0.246）和年龄<65岁（p = 0.304）似乎与更高的移位风险相关。累积翻修率为2.23%。因柄移位导致的翻修（0.89%）发生较早（初次手术至翻修的平均时间：3.3个月）。
如果存在下沉，似乎会有明显的初始下沉，之后趋于稳定。柄移位很少是失败或翻修的主要原因。人口统计学因素似乎对移位模式没有显著影响。股骨近端没有放射性透亮线、吸收或肥大支持了干骺端锚固短柄应力遮挡减少的假说。
