Tennent Duncan, Antonios Tony, Arnander Magnus, Ejindu Vivian, Papadakos Nik, Rastogi Anshul, Pearse Yemi
St. George's Hospital and Medical School, London, UK.
Trauma & Orthopaedics, St Peter's Hospital, Surrey, UK.
Bone Jt Open. 2023 Jul 1;4(7):478-489. doi: 10.1302/2633-1462.47.BJO-2023-0066.R1.
Glenoid bone loss is a significant problem in the management of shoulder instability. The threshold at which the bone loss is considered "critical" requiring bony reconstruction has steadily dropped and is now approximately 15%. This necessitates accurate measurement in order that the correct operation is performed. CT scanning is the most commonly used modality and there are a number of techniques described to measure the bone loss however few have been validated. The aim of this study was to assess the accuracy of the most commonly used techniques for measuring glenoid bone loss on CT.
Anatomically accurate models with known glenoid diameter and degree of bone loss were used to determine the mathematical and statistical accuracy of six of the most commonly described techniques (relative diameter, linear ipsilateral circle of best fit (COBF), linear contralateral COBF, Pico, Sugaya, and circle line methods). The models were prepared at 13.8%, 17.6%, and 22.9% bone loss. Sequential CT scans were taken and randomized. Blinded reviewers made repeated measurements using the different techniques with a threshold for theoretical bone grafting set at 15%.
At 13.8%, only the Pico technique measured under the threshold. At 17.6% and 22.9% bone loss all techniques measured above the threshold. The Pico technique was 97.1% accurate, but had a high false-negative rate and poor sensitivity underestimating the need for grafting. The Sugaya technique had 100% specificity but 25% of the measurements were incorrectly above the threshold. A contralateral COBF underestimates the area by 16% and the diameter by 5 to 7%.
No one method stands out as being truly accurate and clinicians need to be aware of the limitations of their chosen technique. They are not interchangeable, and caution must be used when reading the literature as comparisons are not reliable.
肩胛盂骨质流失是肩关节不稳治疗中的一个重要问题。被认为“严重”到需要进行骨重建的骨质流失阈值一直在稳步下降，目前约为15%。这就需要进行精确测量，以便实施正确的手术。CT扫描是最常用的方式，有多种测量骨质流失的技术被描述，但很少有经过验证的。本研究的目的是评估CT上测量肩胛盂骨质流失的最常用技术的准确性。
使用具有已知肩胛盂直径和骨质流失程度的解剖学精确模型，来确定六种最常描述的技术（相对直径、同侧线性最佳拟合圆（COBF）、对侧线性COBF、皮科法、菅谷法和环线法）的数学和统计准确性。模型的骨质流失率分别设定为13.8%、17.6%和22.9%。进行连续CT扫描并随机化。不知情的审阅者使用不同技术进行重复测量，理论上骨移植的阈值设定为15%。
在骨质流失率为13.8%时，只有皮科技术测量结果低于阈值。在骨质流失率为17.6%和22.9%时，所有技术测量结果均高于阈值。皮科技术的准确率为97.1%，但假阴性率高，敏感性差，低估了移植的必要性。菅谷技术的特异性为100%，但25%的测量结果错误地高于阈值。对侧COBF法低估面积16%，直径低估5%至7%。
没有一种方法被证明是真正准确的，临床医生需要意识到他们所选择技术的局限性。这些方法不可相互替代，在阅读文献时必须谨慎，因为比较结果并不可靠。
