Department of Orthopaedic Surgery, Inselspital, Bern University Hospital, Switzerland, Freiburgstrasse 3, 3010, Bern, Switzerland.
Department of Orthopaedic Surgery, Spital STS AG, Hospital Thun, Thun, Switzerland.
Int Orthop. 2019 Dec;43(12):2697-2705. doi: 10.1007/s00264-018-04284-9. Epub 2019 Jan 20.
The acetabular reinforcement ring with a hook (ARRH) has been designed for acetabular total hip arthroplasty (THA) revision. Additionally, the ARRH offers several advantages when used as a primary implant especially in cases with altered acetabular morphology. The implant facilitates anatomic positioning by placing the hook around the teardrop and provides a homogenous base for cementing the polyethylene cup. Therefore, the implant has been widely used in primary total hip arthroplasty at our institution. The present study reports the long-term outcome of the ARRH after a minimum follow-up of 20 years.
Two hundred and ten patients with 240 primary THAs performed between April 1987 and December 1991 using the ARRH were retrospectively reviewed after a minimum follow-up of 20 years. Twenty-three of 240 hips were lost to follow-up, 110 patients with 124 THAs had deceased without having a revision surgery performed. This left 93 hips for final evaluation. Of those, 75 hips were assessed clinically and radiographically after a mean follow-up of 23.1 years (range 21.1-26.1 years). In 18 cases, clinical and radiographic assessment was omitted because implant revision had been performed prior to the follow-up investigation. The primary endpoint was defined as revision for aseptic loosening.
Out of the 93 hips available for final evaluation, 14 hips were revised for aseptic loosening; another four were revised for other reasons (deep infection n = 2, recurrent dislocation n = 2). The survival probability of the cup was 0.96 (95% confidence interval 0.93-0.99) after 20 years with aseptic loosening as endpoint. Radiographic analysis of the surviving 75 hips showed at least one sign of radiographic loosening in 24 hips. The mean Merle d'Aubigne score increased from 8 points pre-operatively to 15 points at final follow-up (7.5 ± 1.8 vs 15.0 ± 2.3, p < 0.001). The mean HHS was 85 ± 14 at final follow-up. Radiographic loosening did not correlate with the clinical outcome.
The long-term results of the ARRH in primary THA are comparable to results with standard cemented cups and modern cementless cups. We believe that the ARRH is a versatile implant for primary THA, especially in cases with limited acetabular coverage and altered acetabular bone stock where the ARRH provides sufficient structural support for a cemented cup.
带钩髋臼加强环（ARRH）被设计用于髋臼全髋关节置换术（THA）翻修。此外，ARRH 在作为主要植入物使用时具有几个优势，特别是在髋臼形态改变的情况下。该植入物通过将钩子放置在泪滴周围来促进解剖定位，并为骨水泥聚乙烯杯提供均匀的基础。因此，该植入物在我们机构中已广泛用于初次全髋关节置换术。本研究报告了经过至少 20 年随访的 ARRH 的长期结果。
对 1987 年 4 月至 1991 年 12 月期间使用 ARRH 进行的 240 例初次 THA 的 210 例患者进行了回顾性研究，随访时间至少为 20 年。240 髋中有 23 髋失访，110 例患者中有 124 髋因未行翻修手术而死亡。这为最终评估留下了 93 髋。其中，75 髋在平均 23.1 年（范围 21.1-26.1 年）的随访后进行了临床和影像学评估。在 18 例中，由于在随访调查之前已经进行了植入物翻修，因此省略了临床和影像学评估。主要终点定义为无菌性松动的翻修。
在 93 例可进行最终评估的髋中，有 14 髋因无菌性松动而翻修，另有 4 髋因其他原因翻修（深部感染 n=2，复发性脱位 n=2）。20 年后，以无菌性松动为终点时，杯的生存率为 0.96（95%置信区间 0.93-0.99）。对幸存的 75 髋进行影像学分析显示，24 髋中至少有一个影像学松动的迹象。术前 Merle d'Aubigne 评分为 8 分，最终随访时为 15 分（7.5±1.8 与 15.0±2.3，p<0.001）。最终随访时的 HHS 平均为 85±14。影像学松动与临床结果无关。
在初次 THA 中，ARRH 的长期结果与标准骨水泥杯和现代非骨水泥杯的结果相当。我们认为，ARRH 是初次 THA 的一种多功能植入物，特别是在髋臼覆盖范围有限和髋臼骨量改变的情况下，ARRH 为骨水泥杯提供了足够的结构支撑。
