Background

The accuracy of surgeon-defined assessment (SDA) of soft tissue balance in total knee arthroplasty (TKA) is poorly understood despite balance being considered a significant determinant of surgical success. The study’s hypothesis was that intra-operative SDA is a poor predictor of coronal balance in TKA.

Methods

A prospective, multicenter study assessing accuracy of SDA of balance was conducted in 250 patients (285 TKAs). Eight surgeons and thirteen trainees participated, and all were blinded to sensor measurements. The primary outcome was test accuracy of SDA measured at 10°, 45° and 90° compared to sensor measures as the gold standard test. Cohen’s kappa coefficient was calculated to determine chance-corrected agreement. Secondary outcomes include the relationship of SDA to level of surgical experience, analysis of between-surgeon differences, and the influence of patient and operative factors on SDA accuracy.

Results

Average accuracy of SDA was 58.3%, 61.2% and 66.5% at 10°, 45° and 90° respectively. Cohen’s kappa coefficient was 0.18 at all angles and rated as “slight agreement”. SDA sensitivities to correctly identify a balanced knee (76.2% at 10°; 82.6% at 45°; 83.2% at 90°) were approximately twice specificities to correctly identify an unbalanced knee (42.6% at 10°; 34.1% at 45°; 41.4% at 90°). Surgical experience (surgeon versus trainee) had no effect on capacity to determine balance. Considerable between-surgeon variability was found (33–65% at 10°, 41–73% at 45°, 55–89% at 90°).

Conclusion

SDA was a poor predictor of balance, particularly when assessing the unbalanced TKA. Surgeon experience had no effect on test accuracy and considerable between-surgeon variability was recorded. These findings question the accuracy of SDA in TKA.

Trial Registration Number: ACTRN# 12618000817246.

背景

尽管平衡被认为是手术成功的重要决定因素，但对全膝关节置换术（TKA）中软组织平衡的外科医生定义评估（SDA）的准确性知之甚少。该研究的假设是，术中SDA不能很好地预测TKA的冠状动脉平衡。

方法

对250名患者（285 TKA）进行了一项前瞻性，多中心研究，评估了平衡SDA的准确性。八名外科医生和十三名学员参加了培训，所有人员都无法进行传感器测量。主要结果是与传感器测量作为金标准测试相比，在10°，45°和90°下测得的SDA的测试精度。计算科恩的卡伯系数以确定机会校正后的一致性。次要结果包括SDA与手术经验水平的关系，手术之间差异的分析以及患者和手术因素对SDA准确性的影响。

结果

在10°，45°和90°时，SDA的平均准确度分别为58.3％，61.2％和66.5％。科恩的卡伯系数在所有角度均为0.18，被评为“轻微一致性”。正确识别膝盖平衡的SDA灵敏度（10°时为76.2％； 45°时为82.6％； 90°时为83.2％）大约是正确识别不平衡膝盖的灵敏度（10°时为42.6％； 45°时为34.1％； S45时为34.1％； 90°时为41.4％）。手术经验（外科医生与受训者）对平衡能力没有影响。发现医生之间的差异很大（10°时33-65％，45°时41-73％，90°时55-89％）。

结论

SDA不能很好地预测平衡，特别是在评估不平衡的TKA时。外科医生的经验对测试准确性没有影响，并且记录了相当大的外科医生之间的差异。这些发现质疑SDA在TKA中的准确性。

试用注册号：ACTRN＃12618000817246。