Jong-Min Kim2, Jong-Min Kim2, Byeong-Sam Jeon2, Chang-Rack Lee2, Sung-Joon Lim2, Kyung-Ah Kim3, Seong-Il Bin4. 1. Department of Orthopaedic Surgery, College of Medicine, Kosin University, Kosin Gospel Hospital, Busan, Republic of Korea. 2. Department of Orthopedic Surgery, College of Medicine, Asan Medical Center, University of Ulsan, Seoul, Republic of Korea. 3. Department of Biomedical Engineering, College of Medicine, Chungbuk National University, Cheongju, Republic of Korea. 4. Department of Orthopedic Surgery, College of Medicine, Asan Medical Center, University of Ulsan, Seoul, Republic of Korea. Electronic address: sibin@amc.seoul.kr.
Abstract
PURPOSE: The aim of this study was to compare the magnetic resonance imaging (MRI) evaluation of transplanted meniscal allograft with second-look arthroscopy and evaluate the sensitivity, specificity, and accuracy of MRI for assessing graft status. METHODS: From 1996 to 2012, among 290 knees that underwent meniscal allograft transplantation and received follow-up examination for more than 1 year, those knees that underwent second-look arthroscopy were reviewed. Patients with no postoperative MRI and patients with a time gap between postoperative MRI and second-look arthroscopy of more than 3 months were excluded. Anatomically, the meniscus was divided into 3 segments: anterior one-third, mid body, and posterior one-third. Each part of the meniscus was evaluated using both methods. Grade 3 MRI signal intensity was diagnosed as a meniscal tear radiologically. By use of second-look arthroscopy as the standard, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of postoperative MRI were assessed in each segment of the grafts. RESULTS: Twenty knees were retrospectively enrolled. The specificity, PPV, and accuracy for the anterior one-third were lower than those for the mid body and posterior one-third (specificity of 35.3% v 91.7% and 90%, respectively; PPV of 21.4% v 87.5% and 90.9%, respectively; and accuracy of 45% v 90% and 95%, respectively). However, the sensitivity and NPV were similar among the anterior one-third, mid body, and posterior one-third (sensitivity of 100%, 87.5%, and 100%, respectively; and NPV of 100%, 91.7%, and 100%, respectively). There were no significant differences in the comparison between the diagnostic MRI values of lateral grafts and medial grafts. Of 5 cases that showed grade 3 signal at only the anterior one-third section, 60% had no clinical signs. There were no graft tears in any cases. CONCLUSIONS: The anterior one-third of grafts showed low specificity, PPV, and accuracy of postoperative MRI compared with the mid body and posterior one-third. MRI tended to grade the anterior one-third more poorly than second-look arthroscopy. These features should be considered when evaluating transplanted meniscal allografts on postoperative MRI. LEVEL OF EVIDENCE: Level III, study of non-consecutive patients evaluating a diagnostic test with a gold standard.
PURPOSE: The aim of this study was to compare the magnetic resonance imaging (MRI) evaluation of transplanted meniscal allograft with second-look arthroscopy and evaluate the sensitivity, specificity, and accuracy of MRI for assessing graft status. METHODS: From 1996 to 2012, among 290 knees that underwent meniscal allograft transplantation and received follow-up examination for more than 1 year, those knees that underwent second-look arthroscopy were reviewed. Patients with no postoperative MRI and patients with a time gap between postoperative MRI and second-look arthroscopy of more than 3 months were excluded. Anatomically, the meniscus was divided into 3 segments: anterior one-third, mid body, and posterior one-third. Each part of the meniscus was evaluated using both methods. Grade 3 MRI signal intensity was diagnosed as a meniscal tear radiologically. By use of second-look arthroscopy as the standard, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of postoperative MRI were assessed in each segment of the grafts. RESULTS: Twenty knees were retrospectively enrolled. The specificity, PPV, and accuracy for the anterior one-third were lower than those for the mid body and posterior one-third (specificity of 35.3% v 91.7% and 90%, respectively; PPV of 21.4% v 87.5% and 90.9%, respectively; and accuracy of 45% v 90% and 95%, respectively). However, the sensitivity and NPV were similar among the anterior one-third, mid body, and posterior one-third (sensitivity of 100%, 87.5%, and 100%, respectively; and NPV of 100%, 91.7%, and 100%, respectively). There were no significant differences in the comparison between the diagnostic MRI values of lateral grafts and medial grafts. Of 5 cases that showed grade 3 signal at only the anterior one-third section, 60% had no clinical signs. There were no graft tears in any cases. CONCLUSIONS: The anterior one-third of grafts showed low specificity, PPV, and accuracy of postoperative MRI compared with the mid body and posterior one-third. MRI tended to grade the anterior one-third more poorly than second-look arthroscopy. These features should be considered when evaluating transplanted meniscal allografts on postoperative MRI. LEVEL OF EVIDENCE: Level III, study of non-consecutive patients evaluating a diagnostic test with a gold standard.