Vella-Baldacchino Martinique, Cipolla Alessandra, Asghar Zahid, LiArno Sally, Faizan Ahmad, Argenson Jean-Noel, Ollivier Matthieu
Department of Surgery & Cancer, MSk Lab - Imperial College London, Sir Michael Uren Hub, 86 Wood Ln, London, W12 0BZ, UK.
University of Turin, CTO Hospital (C.T.O. Centro Traumatologico Ortopedico), Via Gianfranco Zuretti, 29, Torino, 10126, TO, Italy.
Sci Rep. 2025 Jan 2;15(1):89. doi: 10.1038/s41598-024-83663-2.
Our study aims to investigate if the ratios proposed by Insall-Salvati and Caton-Deschamps follow the theory of normal distribution levels in a healthy population. 434 skeletal mature, healthy knees were obtained from a CT-scan-based modelling system (SOMA). Patellae height ratios were measured using the Insall-Salvati ratio and the Caton-Deschamps index. The patella height ratios of the sample population were plotted on a quantile plot and diagnosed as patella alta, baja or normal using the original ratio definitions. The study population patella height values at the 95th, 98th and 5th centiles were identified and compared to those described as alta or baja by Insall-Salvati and Caton-Deschamps. This meant that if the patient had patella alta, this would be defined as a ratio of ≥ 1.2 and hypothesised that this would align at the 98th centile of the study population, whilst if diagnosed as patella baja (≤ 0.74), this should align at the 5th centile of the population. The inter-rater reliability of both ratios was calculated using kappa statistics. Two authors made all calculations and compared them for consistency using the intraclass correlation coefficient. For the Insall-Salvati ratio, the study population's value at the 98th centile was equivalent to what Insall-Salvati describes as alta, a ratio of ≥ 1.2. In the study population, patients are overdiagnosed if using the Insall-Salvati ratio as patella baja ≤ 0.74, as the value at the 5th centile in the study population was 0.59. Using the Caton-Deschamps index, the 95th centile was 1.3, higher than the patella alta ratio determined by Caton as a ratio ≥ 1.2. Using Caton-Deschamps, patients are being underdiagnosed if utilising a patella baja ratio of ≤ 0.6. In our population, the 5th centile was 0.75. The two ratios had a kappa coefficient of 0.01, which indicates poor inter-rater reliability. Depending on the ratio used, caton-Deschamps and Insall-Salvati ratios diagnose patients as alta or baja differently. The current patella height ratios have originated from very small, select population samples. The future of patella height discussion should begin with data representing large populations. Then, we can discuss the upper and lower limits of abnormality.
我们的研究旨在调查Insall-Salvati和Caton-Deschamps提出的比率是否符合健康人群的正态分布水平理论。从基于CT扫描的建模系统（SOMA）中获取了434个骨骼成熟、健康的膝关节。使用Insall-Salvati比率和Caton-Deschamps指数测量髌骨高度比率。将样本人群的髌骨高度比率绘制在分位数图上，并根据原始比率定义诊断为高位髌骨、低位髌骨或正常。确定了研究人群在第95、98和第5百分位数处的髌骨高度值，并与Insall-Salvati和Caton-Deschamps描述为高位或低位的数值进行比较。这意味着，如果患者为高位髌骨，将定义为比率≥1.2，并假设这将与研究人群的第98百分位数一致，而如果诊断为低位髌骨（≤0.74），则应与人群的第5百分位数一致。使用kappa统计量计算这两个比率的评分者间信度。两位作者进行了所有计算，并使用组内相关系数比较计算结果的一致性。对于Insall-Salvati比率，研究人群在第98百分位数处的值与Insall-Salvati描述为高位的比率≥1.2相当。在研究人群中，如果将Insall-Salvati比率中≤0.74作为低位髌骨的标准，则患者被过度诊断，因为研究人群中第5百分位数处的值为0.59。使用Caton-Deschamps指数时，第95百分位数为1.3，高于Caton确定的高位髌骨比率≥1.2。使用Caton-Deschamps指数时，如果将≤0.6的低位髌骨比率作为标准，则患者被诊断不足。在我们的人群中，第5百分位数为0.75。这两个比率的kappa系数为0.01，表明评分者间信度较差。根据所使用的比率，Caton-Deschamps比率和Insall-Salvati比率对患者高位或低位髌骨的诊断不同。当前的髌骨高度比率源自非常小的特定人群样本。髌骨高度讨论的未来应该从代表大量人群的数据开始。然后，我们可以讨论异常的上限和下限。
