G. Tsikandylakis, J. Kärrholm, M. Mohaddes, Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Sahlgrenska University Hospital, Gothenburg, Sweden; and The Swedish Hip Arthroplasty Register, Gothenburg, Sweden N. P. Hailer, Section of Orthopaedics, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; and The Swedish Hip Arthroplasty Register, Gothenburg, Sweden A. Eskelinen, Coxa Hospital of Joint Replacement, Tampere, Finland; and The Finnish Arthroplasty Register, Helsinki, Finland K. T. Mäkelä, Department of Orthopedics and Traumatology, Turku University Hospital, Turku, Finland; and The Finnish Arthroplasty Register, Helsinki, Finland G. Hallan, O. N. Furnes, The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway; and the Department of Clinical Medicine, Faculty of Medicine, University of Bergen, Bergen, Norway A. B. Pedersen, Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark; and The Danish Hip Arthroplasty Register, Aarhus, Denmark S. Overgaard, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Odense, Denmark; the Institute of Clinical Research, University of Southern Denmark, Odense, Denmark; and The Danish Hip Arthroplasty Register, Aarhus, Denmark.
Clin Orthop Relat Res. 2018 Dec;476(12):2367-2378. doi: 10.1097/CORR.0000000000000508.
During the past decade, the 32-mm head has replaced the 28-mm head as the most common head size used in primary THA in many national registries, and the use of 36-mm heads has also increased. However, it is unclear whether 32-mm and 36-mm heads decrease the revision risk in metal-on-polyethylene (MoP) THA compared with 28-mm heads.
QUESTIONS/PURPOSES: (1) In the setting of the Nordic Arthroplasty Register Association database, does the revision risk for any reason differ among 28-, 32-, and 36-mm head sizes in patients undergoing surgery with MoP THA? (2) Does the revision risk resulting from dislocation decrease with increasing head diameter (28-36 mm) in patients undergoing surgery with MoP THA in the same registry?
Data were derived from the Nordic Arthroplasty Register Association database, a collaboration among the national arthroplasty registries of Denmark, Finland, Norway, and Sweden. Patients with primary osteoarthritis who had undergone primary THA with a 28-, 32-, or 36-mm MoP bearing from 2003 to 2014 were included. Patients operated on with dual-mobility cups were excluded. In patients with bilateral THA, only the first operated hip was included. After applying the inclusion criteria, the number of patients and THAs with a complete data set was determined to be 186,231, which accounted for 51% of all hips (366,309) with primary osteoarthritis operated on with THA of any head size and bearing type during the study observation time. Of the included patients, 60% (111,046 of 186,231) were women, the mean age at surgery was 70 (± 10) years, and the median followup was 4.5 years (range, 0-14 years). A total of 101,094 patients had received a 28-mm, 57,853 a 32-mm, and 27,284 a 36-mm head with 32 mm used as the reference group. The revision of any component for any reason was the primary outcome and revision for dislocation was the secondary outcome. Very few patients are estimated to be lost to followup because emigration in the population of interest (older than 65-70 years) is rare. A Kaplan-Meier analysis was used to estimate THA survival for each group, whereas Cox regression models were fitted to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for THA revision comparing the 28- and 36-mm head diameters with the 32-mm head diameters adjusting for age, sex, year of surgery, type of cup and stem fixation, polyethylene type (crosslinked versus conventional), and surgical approach.
In the adjusted Cox regression model, there was no difference in the adjusted risk for revision for any reason between patients with 28-mm (HR, 1.06; 95% CI, 0.97-0.16) and 32-mm heads, whereas the risk of revision was higher for patients with 36-mm heads (HR, 1.14; 95% CI, 1.04-1.26) compared with patients with 32-mm heads. Patients with 28-mm heads had a higher risk of revision for dislocation (HR, 1.67; 95% CI, 1.38-1.98) compared with 32 mm, whereas there was no difference between patients with 36-mm (HR, 0.85; 95% CI, 0.70-1.02) and 32-mm heads.
After adjusting for relevant confounding variables, we found no benefits for 32-mm heads against 28 mm in terms of overall revision risk. However, when dislocation risk is considered, 32-mm heads would be a better option, because they had a lower risk of revision resulting from dislocation. There were no benefits with the use of 36-mm heads over 32 mm, because the transition from 32 to 36 mm was associated with a higher risk of revision for all reasons, which was not accompanied by a decrease in the risk of revision resulting from dislocation. The use of 32-mm heads appears to offer the best compromise between joint stability and other reasons for revision in MoP THA. Further studies with longer followup, especially of 36-mm heads, as well as better balance of confounders across head sizes and better control of patient-related risk factors for THA revision are needed.
Level III, therapeutic study.
在过去的十年中，32 毫米头已取代 28 毫米头成为许多国家登记处中初次全髋关节置换术（THA）最常用的头尺寸，并且 36 毫米头的使用也有所增加。然而，尚不清楚在金属对聚乙烯（MoP）THA 中，32 毫米和 36 毫米头是否比 28 毫米头降低了翻修风险。
问题/目的：（1）在北欧关节置换登记协会数据库中，在接受 MoP THA 手术的患者中，与 28 毫米头相比，32 毫米和 36 毫米头的大小是否会影响任何原因导致的翻修风险？（2）在同一登记处接受 MoP THA 手术的患者中，随着头直径（28-36 毫米）的增加，脱位导致的翻修风险是否会降低？
数据来自北欧关节置换登记协会数据库，该数据库是丹麦、芬兰、挪威和瑞典国家关节置换登记处的合作项目。纳入了 2003 年至 2014 年间接受初次 MoP 髋关节置换术的原发性骨关节炎患者，排除了使用双动杯的患者。在接受双侧 THA 的患者中，仅纳入初次手术的髋关节。在应用纳入标准后，确定了具有完整数据集的患者和 THA 的数量，共 186231 例，占研究观察期间接受任何头尺寸和任何轴承类型初次 THA 的原发性骨关节炎患者总数（366309 例）的 51%。在纳入的患者中，60%（111046/186231）为女性，手术时的平均年龄为 70（±10）岁，中位随访时间为 4.5 年（范围，0-14 年）。共有 101094 例患者接受了 28 毫米头、57853 例接受了 32 毫米头、27284 例接受了 36 毫米头，以 32 毫米头作为参考组。任何原因的任何组件翻修为主要结果，脱位翻修为次要结果。由于感兴趣人群（65-70 岁以上）的移民很少，估计很少有患者失访。使用 Kaplan-Meier 分析估计每组的 THA 生存率，而使用 Cox 回归模型计算调整年龄、性别、手术年份、杯和柄固定类型、聚乙烯类型（交联与常规）和手术入路后，28 毫米和 36 毫米头直径与 32 毫米头直径相比，THA 翻修的风险比（HR）及其 95%置信区间（CI）。
在调整后的 Cox 回归模型中，28 毫米头（HR，1.06；95%CI，0.97-0.16）和 32 毫米头患者之间，任何原因导致的翻修风险无差异，而 36 毫米头患者（HR，1.14；95%CI，1.04-1.26）与 32 毫米头患者相比，翻修风险更高。28 毫米头患者的脱位翻修风险更高（HR，1.67；95%CI，1.38-1.98），而 36 毫米头患者（HR，0.85；95%CI，0.70-1.02）与 32 毫米头患者之间无差异。
在调整了相关混杂变量后，我们没有发现 32 毫米头相对于 28 毫米头在整体翻修风险方面有任何优势。然而，当考虑脱位风险时，32 毫米头是更好的选择，因为它的脱位导致的翻修风险较低。与 32 毫米头相比，使用 36 毫米头没有好处，因为从 32 毫米过渡到 36 毫米会导致所有原因导致的翻修风险增加，而脱位导致的翻修风险并没有降低。在 MoP THA 中，使用 32 毫米头似乎在关节稳定性和其他翻修原因之间提供了最佳的平衡。需要进一步的研究，包括更长时间的随访，尤其是 36 毫米头的研究，以及更好地平衡头尺寸之间的混杂因素，并更好地控制 THA 翻修的患者相关风险因素。
III 级，治疗性研究。
