A. Troelsen, L. H. Ingelsrud, M. G. Thomsen, K. S. Otte, H. Husted, Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark.
O. Muharemovic, Department of Radiology, Centre for Functional and Diagnostic Imaging and Research Copenhagen University Hospital Hvidovre, Copenhagen, Denmark.
Clin Orthop Relat Res. 2020 Sep;478(9):2045-2053. doi: 10.1097/CORR.0000000000001077.
Bicruciate-retaining TKA has been proposed to improve clinical outcomes by maintaining intrinsic ACL function. However, because the unique design of the bicruciate-retaining tibial component precludes a tibial stem, fixation may be compromised. A radiostereometric analysis permits an evaluation of early migration of tibial components in this setting, but to our knowledge, no such analysis has been performed.
QUESTIONS/PURPOSES: We performed a randomized controlled trial using a radiostereometric analysis and asked, at 2 years: (1) Is there a difference in tibial implant migration between the bicruciate-retaining and cruciate-retaining TKA designs? In a secondary analysis, we asked: (2) Is there a difference in patient-reported outcomes (Oxford Knee Score [OKS] and Forgotten Joint Score [FJS] between the bicruciate-retaining and cruciate-retaining TKA designs? (3) What is the frequency of reoperations and revisions for the bicruciate-retaining and cruciate-retaining TKA designs?
This parallel-group trial (ClinicalTrials.gov: NCT01966848) randomized 50 patients with an intact ACL who were eligible to undergo TKA to receive either a bicruciate-retaining or cruciate-retaining TKA. Patients were blinded to treatment allocation. The primary outcome was the maximum total point motion (MTPM) of the tibial component measured with model-based radiostereometric analysis (RSA) at 2 years postoperatively. The MTPM is a translation vector defined as the point in the RSA model that has the greatest combined translation in x-, y- and z-directions. A 1-year postoperative mean MTPM value of 1.6 mm has been suggested as a threshold for unacceptable increased risk of aseptic loosening after both 5 and 10 years. The repeatability of the MTPM was found to be 0.26 mm in our study. Patient-reported outcome measures were assessed preoperatively and at 2 years postoperatively with the OKS (scale of 0-48, worst-best) and FJS (scale of 0-100, worst-best). Baseline characteristics did not differ between groups. At 2 years postoperatively, RSA images were available for 22 patients who underwent bicruciate-retaining and 23 patients who underwent cruciate-retaining TKA, while patient-reported outcome measures were available for 24 patients in each group. The study was powered to detect a 0.2-mm difference in MTPM between groups (SD = 0.2, significance level = 5%, power = 80%).
With the numbers available, we found no difference in MTPM between the bicruciate-retaining and cruciate-retaining groups. The median (interquartile range [IQR]) MTPM was 0.52 mm (0.35 to 1.02) and 0.42 mm (0.34 to 0.70) in the bicruciate-retaining and cruciate-retaining groups, respectively (p = 0.63). There was no difference in the magnitude of improvement in the OKS from preoperatively to 2 years postoperative between the groups (median delta [IQR] for bicruciate-retaining 18 [14 to 23] versus cruciate-retaining 18 [15 to 21], difference of medians 0; p = 0.96). Likewise, there was no difference in the magnitude of improvement in the FJS score from preoperatively to 2 years postoperative between the groups (mean ± SD for bicruciate-retaining 46 ± 32 versus cruciate-retaining 48 ± 16, mean difference, 2; p = 0.80). Three patients in the bicruciate-retaining group underwent arthroscopically assisted manipulation at 3 to 4 months postoperatively, and one patient in the bicruciate-retaining group sustained a tibial island fracture during primary surgery and underwent a revision procedure after 6 months. There were no reoperations or revisions in the cruciate-retaining group.
With the numbers available, we found no differences between the bicruciate-retaining and the cruciate-retaining implants in terms of stable fixation on RSA or patient-reported outcome measure scores at 2 years, and must therefore recommend against the routine clinical use of the bicruciate-retaining device. The complications we observed with the bicruciate-retaining device suggest it has an associated learning curve and the associated risks of novelty with no demonstrable benefit to the patient; it is also likely to be more expensive in most centers. Continued research on this implant should only be performed in the context of controlled trials.
Level II, therapeutic study.
保留交叉韧带的 TKA 被提议通过维持 ACL 的内在功能来改善临床结果。然而，由于保留交叉韧带的胫骨组件的独特设计排除了胫骨柄，因此固定可能会受到影响。放射立体测量分析允许评估这种情况下胫骨组件的早期迁移，但据我们所知，尚未进行过这样的分析。
问题/目的：我们使用放射立体测量分析进行了一项随机对照试验，并在 2 年时提出了以下问题：（1）在保留交叉韧带和不保留交叉韧带的 TKA 设计中，胫骨植入物的迁移是否存在差异？在二次分析中，我们还提出了以下问题：（2）保留交叉韧带和不保留交叉韧带的 TKA 设计在患者报告的结果（牛津膝关节评分[OKS]和遗忘关节评分[FJS]）方面是否存在差异？（3）保留交叉韧带和不保留交叉韧带的 TKA 设计的再手术和翻修频率是多少？
这项平行组试验（ClinicalTrials.gov：NCT01966848）随机将 50 名 ACL 完整的患者分为两组，分别接受保留交叉韧带和不保留交叉韧带的 TKA。患者对治疗分配不知情。主要结果是术后 2 年时使用基于模型的放射立体测量分析（RSA）测量的胫骨组件的最大总点运动（MTPM）。MTPM 是一个平移向量，定义为 RSA 模型中具有最大组合平移的点，在 x、y 和 z 方向上。已经表明，术后 5 年和 10 年，1 年时平均 MTPM 值为 1.6 毫米是无菌性松动风险增加的不可接受阈值。我们的研究发现 MTPM 的重复性为 0.26 毫米。术前和术后 2 年使用 OKS（范围为 0-48，最差-最佳）和 FJS（范围为 0-100，最差-最佳）评估患者报告的结果。两组间基线特征无差异。术后 2 年，22 例接受保留交叉韧带 TKA 和 23 例接受不保留交叉韧带 TKA 的患者获得 RSA 图像，24 例接受保留交叉韧带和不保留交叉韧带 TKA 的患者获得患者报告的结果。该研究的目的是检测两组间 MTPM 差异为 0.2 毫米（SD=0.2，显著性水平=5%，功率=80%）。
根据目前的数字，我们发现保留交叉韧带和不保留交叉韧带组之间的 MTPM 没有差异。保留交叉韧带组和不保留交叉韧带组的中位数（四分位距[IQR]）MTPM 分别为 0.52 毫米（0.35 至 1.02）和 0.42 毫米（0.34 至 0.70）（p=0.63）。两组间术前至术后 2 年 OKS 评分的改善幅度无差异（保留交叉韧带组中位数差值[IQR]为 18 [14 至 23]，不保留交叉韧带组为 18 [15 至 21]，中位数差值为 0；p=0.96）。同样，两组间术前至术后 2 年 FJS 评分的改善幅度也无差异（保留交叉韧带组平均±SD 为 46±32，不保留交叉韧带组为 48±16，平均差值为 2；p=0.80）。保留交叉韧带组中有 3 例患者在术后 3 至 4 个月接受了关节镜辅助手法复位，1 例患者在保留交叉韧带组中发生胫骨岛骨折，在术后 6 个月接受了翻修手术。不保留交叉韧带组无再手术或翻修。
根据目前的数字，我们发现保留交叉韧带和不保留交叉韧带的胫骨组件在 RSA 或患者报告的结果测量方面在 2 年时没有固定差异，因此必须反对常规临床使用保留交叉韧带的装置。我们在保留交叉韧带装置中观察到的并发症表明它具有相关的学习曲线和与新颖性相关的风险，而对患者没有明显的益处；在大多数中心，它也可能更昂贵。只有在对照试验的背景下，才能继续对该植入物进行研究。
II 级，治疗性研究。
