2023 ISAKOS Biennial Congress ePoster
The Optimal Measurement Method Considering Reliability and Validity in the Anterior Knee Laxity of Anterior Cruciate Ligament Tears
Sangwoo Jeon, MD, Seoul KOREA, REPUBLIC OF
Sung-Hwan Kim, MD, PhD, Seoul KOREA, REPUBLIC OF
25, Magokdong-ro 2-gil, Gangseo-gu, Seoul, Republic of Korea, Ewha Womans University, College of Medicine , SEOUL, KOREA, REPUBLIC OF
FDA Status Cleared
Summary
The Modified lateral method is recommended with high reliability considering the difference in the bilateral knee positions and anatomical discriminability on the stress radiographs for evaluating anterior knee laxity with TelosTM. The lateral to lateral method best reflected the KT-2000 arthrometer.
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Abstract
Background
Stress radiographs comparable to arthrometer provide an objective, quantifiable assessment of ligamentous knee injury. The reliability is affected by the variations of the patient's posture and difficulty of discriminating anatomical landmark due to the variations on the stress radiographs. The goal of this study was to seek an optimal method with high reliability given that these two factors cause errors in evaluating anterior knee laxity on stress radiographs and high validity comparing the laxity values to those of KT-2000 arthrometer.
Methods
Anterior knee laxity of 77 patients were measured by the TelosTM and the KT-2000 arthrometer preoperatively. The side to side difference measurements with 3 conventional measuring methods (center to center, lateral to lateral, medial to medial) and 1 proposed method (Modified lateral) were done repeatedly with 2 weeks interval by two different surgeons. The knee position on the stress radiograph was evaluated according to the quality score criteria. Intraclass correlation coefficients were analyzed to evaluate the intraobserver and interobserver reliability of the measurements, and compared between high and low radiograph quality score group in each methods. The validities were assessed by comparing the KT-2000 and the TelosTM using Pearson correlation (r value).
Results
The Modified lateral (ML: ICCs, 0.895) method showed the best ICCs followed by center to center(CC:ICCs, 0.858) and medial to medial(MM:ICCs,0.858) and lateral to lateral(LL:ICCs.0.791) methods without considering the difference in the bilateral knee positions. There was a statistically significant difference between the ML and the LL. (P<0.05). ML( ICCs, 0.882) method in low quality score group and CC(ICCs, 0.923) method in high quality score group showed the best ICCs each. There was a statistically significant difference between the two groups in CC(ICCs, 0.804(low) vs 0.923(high)) and LL(ICCs, 0.704(low) vs 0.864(high)) (P<0.05). The correlation between the KT-2000 and the TelosTM was the strongest in LL( r=0.452, p=0.007) followed by CC (r =0.334, p =0.03),ML (r=0.306, p=0.01), MM (r=0.251, p=0.023). There were no statistically significant differences among them.
Conclusion
The Modified lateral method is recommended with high reliability considering the difference in the bilateral knee positions and anatomical discriminability on the stress radiographs for evaluating anterior knee laxity with TelosTM. The lateral to lateral method best reflected the KT-2000 arthrometer.