Mark J Sando1, Sean S Rajaee2, Joseph P Liu3, Michael Banffy4, Orr Limpisvasti4, John V Crues3. 1. 1 Orthopaedic Medical Group of Tampa Bay, Tampa, FL. 2. 2 Department of Orthopaedic Surgery, Cedars Sinai Medical Center, 444 San Vicente Blvd, No. 603, Los Angeles, CA 90048. 3. 3 RADNET, Los Angeles, CA. 4. 4 Kerlan-Jobe Orthopaedic Clinic, Los Angeles, CA.
Abstract
OBJECTIVE: The purpose of this study was to compare standard knee arthroscopic and MRI findings and measurements for visualization of the femoral condyle articular cartilage. The hypothesis was that certain posterior cartilage defects identified with MRI may not be accessible with routine arthroscopy. MATERIALS AND METHODS: Six cadaveric knees were examined by routine arthroscopy through standard inferomedial and inferolateral portals. Suture anchors were inserted into the femoral condyles at 30°, 60°, 90°, and 120° of flexion as markers of the cartilage surface at the most posterior aspect of the condyle that could be accessed at each degree of flexion. Each specimen was then examined with 3-T MRI and gross dissection. Measurements were obtained and compared. RESULTS: During arthroscopy at 90° of knee flexion, only 5.83 mm of the medial femoral condyle and 6.83 mm of the lateral femoral condyle were visualized posterior to the anchor placed at 90° of flexion. These arthroscopic measurements were statistically significant underestimates of the actual amount of cartilage identified posterior to the 90° anchor at gross dissection (medial condyle, 44.20 mm; lateral condyle, 37.50 mm) and MRI (medial, 41.33 mm; lateral, 38.87 mm). This indicates that 85.9% of the medial and 81.8% of the lateral posterior articular cartilage of the femoral condyle seen at MRI were not visualized during arthroscopy. CONCLUSION: More than 80% of the articular cartilage proximal to the menisci seen at MRI is not visible during routine arthroscopy. This far posterior articular cartilage should be called the hidden zone.
OBJECTIVE: The purpose of this study was to compare standard knee arthroscopic and MRI findings and measurements for visualization of the femoral condyle articular cartilage. The hypothesis was that certain posterior cartilage defects identified with MRI may not be accessible with routine arthroscopy. MATERIALS AND METHODS: Six cadaveric knees were examined by routine arthroscopy through standard inferomedial and inferolateral portals. Suture anchors were inserted into the femoral condyles at 30°, 60°, 90°, and 120° of flexion as markers of the cartilage surface at the most posterior aspect of the condyle that could be accessed at each degree of flexion. Each specimen was then examined with 3-T MRI and gross dissection. Measurements were obtained and compared. RESULTS: During arthroscopy at 90° of knee flexion, only 5.83 mm of the medial femoral condyle and 6.83 mm of the lateral femoral condyle were visualized posterior to the anchor placed at 90° of flexion. These arthroscopic measurements were statistically significant underestimates of the actual amount of cartilage identified posterior to the 90° anchor at gross dissection (medial condyle, 44.20 mm; lateral condyle, 37.50 mm) and MRI (medial, 41.33 mm; lateral, 38.87 mm). This indicates that 85.9% of the medial and 81.8% of the lateral posterior articular cartilage of the femoral condyle seen at MRI were not visualized during arthroscopy. CONCLUSION: More than 80% of the articular cartilage proximal to the menisci seen at MRI is not visible during routine arthroscopy. This far posterior articular cartilage should be called the hidden zone.
Authors: Jacob C Mandell; Jeffrey A Rhodes; Nehal Shah; Glenn C Gaviola; Andreas H Gomoll; Stacy E Smith Journal: Skeletal Radiol Date: 2017-07-17 Impact factor: 2.199