Background:Posterior tibial slope (PTS) has been identified as a possible modifiable risk factor for anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) failure. However, the findings in the literature are inconsistent. This may be explained by several different reasons, including different measurement methods, differing definitions of ACLR failure, and possible inclusion of suboptimal films.Purpose:To compare PTS values obtained using plain radiographs (XR-PTS) in a young (≤21 years of age), skeletally mature patient population with those obtained using magnetic resonance imaging (MRI), as well as to quantify the number of suboptimal lateral knee radiographs obtained across an integrated health care system and determine the potential effect of including these radiographs on summary statistics of XR-PTS.Study Design:Case-control study; Level of evidence, 3.Methods:Skeletally mature adolescent and young adult patients ≤21 years of age were identified from the ACLR registry of Kaiser Permanente. The cases of concern were patients requiring revision ACLR. The controls were patients who had an ACLR and did not require a revision procedure. The XR-PTS measurements were made on plain radiographs by a single blinded reviewer. These results were compared with measurements obtained using MRI. The quality of each plain radiograph was evaluated by measuring posterior/distal femoral condylar overlap and length of tibial diaphysis captured on the radiograph. Summary statistics with and without inclusion of measurements made on suboptimal radiographs were calculated.Results:Of the initial 634 patients with ACLR (317 case-control pairs), 561 (88.5%) had radiographs available and were included for the analysis comparing radiograph to MRI slope measurements. For the evaluation of slope between case and control pairs with radiograph information available, there were 257 case-control pairs; there were 124 pairs when those with suboptimal radiographs were excluded. There was no difference in MRI-measured lateral tibial posterior slope or medial tibial posterior slope for the 257 case-control pairs with XR-PTS information and for the 124 pairs with optimal radiographs. XR-PTS in the revision cohort was significantly steeper than in the control group when suboptimal radiographs were included in the analysis. There was no difference when patients with suboptimal radiographs were excluded. PTS measurements made on plain radiographs were larger than those made on MRI. There was a poor correlation between measurements made using these 2 modalities ( r = 0.22 for radiograph and medial PTS).Conclusion:This study did not find a significantly steeper XR-PTS in patients who had to undergo revision ACLR when suboptimal radiographs were not included in the analysis. The present study's results confirmed the findings from a previous study of the same patient population that used MRI. However, there was poor correlation between PTS measurements made using plain radiograph and MRI.

中文翻译：

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X 线平片与 MRI 测量的胫骨后斜及其与翻修前交叉韧带重建的相关性：一项匹配的病例对照研究


背景： 胫骨后斜 （PTS） 已被确定为前交叉韧带 （ACL） 损伤和 ACL 重建 （ACLR） 失败的可能可改变危险因素。然而，文献中的发现并不一致。这可能是由几个不同的原因来解释的，包括不同的测量方法、ACLR 失败的不同定义以及可能包含次优的薄膜。目的： 比较使用平片 （XR-PTS） 在年轻 （≤21 岁）、骨骼成熟的患者群体中获得的 PTS 值与使用磁共振成像 （MRI） 获得的 PTS 值，以及量化在综合医疗保健系统中获得的次优膝关节外侧 X 线片的数量，并确定包括这些 X 线片对 XR-PTS 汇总统计的潜在影响。研究设计： 病例对照研究;证据水平， 3.方法： 从 Kaiser Permanente 的 ACLR 登记处确定了骨骼成熟的青少年和年轻成人患者 ≤21 岁。值得关注的病例是需要翻修 ACLR 的患者。对照组是患有 ACLR 且不需要翻修手术的患者。XR-PTS 测量由一名盲法评价员在 X 线平片上进行。将这些结果与使用 MRI 获得的测量值进行了比较。通过测量 X 光片上捕获的股骨后/远端髁重叠和胫骨骨干长度来评估每张 X 线平片的质量。计算包括和不包括次优 X 光片测量的汇总统计数据。结果： 在最初的 634 例 ACLR 患者 （317 对病例对照） 中，561 例 （88.5%） 有 X 线片，并被纳入 X 线片与 MRI 斜率测量的比较分析。 对于可用 X 光片信息对病例和对照对之间的斜率评估，有 257 个病例-对照对;当排除 X 线片不佳的患者时，有 124 对。MRI 测量的胫骨外侧后坡或胫骨内侧后坡对于具有 XR-PTS 信息的 257 对病例对照对和具有最佳 X 光片的 124 对没有差异。当分析中包括次优 X 光片时，翻修队列中的 XR-PTS 明显比对照组陡峭。当排除 X 线片不佳的患者时，没有差异。在 X 线平片上进行的 PTS 测量值大于在 MRI 上进行的 PTS 测量值。使用这 2 种模式进行的测量之间的相关性较差 （ X 光片和内侧 PTS 的 r = 0.22）。结论： 当次优 X 线片未纳入分析时，本研究未发现必须接受翻修 ACLR 的患者 XR-PTS 显著陡峭。本研究的结果证实了之前对使用 MRI 的同一患者群体进行的研究结果。然而，使用 X 线平片和 MRI 进行的 PTS 测量之间的相关性较差。