中重度滑车发育不良的手术规划需同时测量相对和绝对髌骨高度
简介
本研究评估了髌骨滑车指数（PTI）在中重度滑车发育不良中识别相对高位髌骨的准确性。回顾性分析120例患者术前膝关节X线片及MRI，按Oswestry Bristol分型（OBC）分组，比较PTI与Caton-Deschamps指数（CD）。结果显示：在正常及轻度滑车发育不良中，CD与PTI诊断高位髌骨无显著差异（p>0.05）；但在中度（OBC 3型）和重度…
英文摘要
BACKGROUND: This study assessed the accuracy of the patellotrochlea index (PTI) in identifying relative patella alta in trochlea dysplasia. We hypothesise that PTI fails to appreciate relative patella alta in trochlea dysplasia, the role of both absolute and relative patella height measurements was assessed. METHOD: This is a retrospective comparative radiographic study. Pre-operative knee radiographs and Magnetic Resonance Imaging (MRI) were reviewed. Cases were grouped using the Oswestry Bristol Classification (OBC). Patella instability cases were reviewed, alongside MPFL, TTO and trochleoplasty; ACL reconstruction patients were reviewed for normal trochlea morphology. 120 included. Patella height measurements were PTI and the Caton-Deschamps ratio (CD). Statistical analysis included McNemar's tests, linear regression, one-way ANOVA, and Pearson's correlation, with significance set at p < 0.05. RESULTS: In normal and mild dysplastic trochleas there was no significant difference in patella alta identified by CD and PTI (p > 0.05). In moderate (OBC 3) and severe (OBC 4) trochlea dysplasia there was only 30% and 40% agreement, respectively (p < 0.05) for CD and PTI. Sensitivity and specificity analysis showed 30% had a diagnostic CD with a negative PTI. Linear regression analysis indicated that a PTI of approximately 0.42 is a potential novel diagnostic point for relative patella alta in moderate and severe dysplasia. CONCLUSIONS: PTI fails to diagnose relative patella alta in moderate and severe trochlea dysplasia. We would advocate the use of both CD and PTI in preoperative assessment of patella instability. The potential novel diagnostic threshold of 0.42 to diagnose relative patella alta needs further research with outcome correlation.