A comparison of arthroscopic diagnosis of ramp lesion and pre-operative MRI evaluation Yasuma S, Nozaki M, Kobayashi M, Kawanishi Y Yoshida M, Mitsui H, Nagaya Y, Iguchi H, Murakami H Department of Orthopaedic Surgery Nagoya City University, Nagoya, Japan
Sanshiro Yasuma, MD There is no financial disclosure to report for this study.
Ramp lesion Longitudinal tear of the posterior horn of the medial meniscus (PHMM) adjoining the menisco-capsular (MC) junction associated with ACL ruptures. Strobel MJ, Manual of Arthroscopic Surgery, 1988 PH MM Menisco-capsular (MC) junction or Red-Red zone Ramp lesion : posterior capsule Strobel MJ, Manual of Arthroscopic Surgery, Springer, 2002 Mathieu T, et al. Arthroscopy, 2016
Ramp lesion Increase of knee instability Ahn JH, et al. AJSM, 2011 Peltier A, et al. KSSTA, 2015 Nicholas N, et al. AJSM, 2018 Difficulty of spontaneous healing necessity of meniscal repair Ahn JH, et al. AJSM, 2010 Difficulty of diagnosis MRI: Low sensitivity (0~61%) Bollen SR, et al. JBJS Br, 2010 Nicholas N, et al. AJSM, 2017 Mathieu T, et al. Arthroscopy, 2016 Arthroscopy Anterior visualization Impossible to diagnose Necessity of systematic arthroscopic exploration Sonnery-Cottet, et al, AJSM, 2014
Purpose To evaluate the prevalence of ramp lesion by systematic arthroscopic exploration To compare the arthroscopic diagnosis of ramp lesion and pre-operative MRI evaluation.
Materials and Methods 149 ACL-injured patients Systematic arthroscopic exploration of ramp lesion Step 1: Anterior visualization via an anterolateral portal Step 2: Inter-condylar visualization with the arthroscope introduced deeply into the posteromedial compartment Step 3: Probing and debridement through the posteromedial (PM) portal with Inter-condylar visualization Step 1 Step 2 Step 3 MFC Sonnery-Cottet, et al, AJSM, 2014 MFC PHMM PHMM MFC: Medial femoral condyle Ramp lesion
Materials and Methods <Evaluation> Prevalence of ramp lesion Number of cases for each step when ramp lesion was identified Location of ramp lesion (MC junction or Red-Red zone) Pre-operative MRI (138 of the 149 cases) Sagittal proton density fat saturation High signal intensity at the posterior margin of the PHMM MRI (+) Yes No MRI ( ) <Evaluation> Diagnostic rate for ramp lesion by pre-operative MRI Sensitivity Specificity
Results 1: Arthroscopic evaluation Prevalence of ramp lesion: 17.4% (26 of the 149 cases) Number of cases for each step when ramp lesion was identified Step 1: 10 cases, Step 2: 11 cases, Step 3: 5 cases Inter-condylar visualization Procedures through PM portal Effective in identifying ramp lesion Location of ramp lesion MC junction: 13 cases, Red-Red zone: 12 cases, Both: 1 case PH MM MFC MC junction Red-Red zone
Results 2: MRI evaluation Ramp (+) Ramp (-) MRI (+) 16 7 MRI (-) 8 107 Total Sensitivity: 66.7% Specificity: 93.9% Ramp (+): Arthroscopic diagnosis of ramp lesion Ramp (-): Arthroscopic diagnosis of no ramp lesion Ramp lesion MC junction Red-Red zone MRI (+) 6 10 MRI (-) 7 1 Sensitivity MC junction: 42.9% Red-Red zone: 90.9% Low sensitivity of MRI in detecting ramp lesion at MC junction PH MM
Discussion 1: Arthroscopic diagnosis of ramp lesion Prevalence of ramp lesion 17 of 183 cases (9.3%) Bollen SR, et al. JBJS Br, 2010 144 of 868 cases (16.6%) Xin Liu, et al. AJSM, 2011 769 of 3214 cases (23.9%) Our study: 26 of 149 cases (17.4%) Sonnery-Cottet, et al. AJSM, 2018 Diagnostic rate of ramp lesion Step 1 (Anterior view): 0%, Step 2 (Inter-condylar view): 58% Step 3 (Procedures through PM portal): 100% Our study Step 1: 38.5% (10/26) Step 2: 80.8% (21/26) Step 3: 100% (26/26) Sonnery-Cottet, et al, AJSM, 2014 Necessity of inter-condylar view and PM portal for diagnosis of ramp lesion
Discussion 2: Diagnostic rate for ramp lesion by MRI Sensitivity of pre-operative MRI 0% (0 of 11 cases) Bollen SR, et al. JBJS Br, 2010 48% (24 of 50 cases) Nicholas N, et al. AJSM, 2017 61% (80 of 132 cases) Mathieu T, et al. Arthroscopy, 2016 Our study 66.7% (16/24) Our study MC junction: 42.9% (6/13), Red-Red zone: 90.9% (10/11) Difficult to diagnose ramp lesion at MC junction by MRI PH MM MC junction
Conclusion The prevalence of ramp lesion was 17.4%. Inter-condylar visualization and the creation of a posteromedial portal was effective in identifying ramp lesion. Low sensitivity in detecting ramp lesion was seen especially at the menisco-capsular junction on pre-operative MRI. Careful arthroscopic exploration should be required so as not to overlook ramp lesion, even when it is not indicated on pre-operative MRI.
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