Diagnostic Accuracy of Sequential Arthroscopic Approach for Ramp Lesions of the Posterior Horn of the Medial Meniscus in Anterior Cruciate Ligament-Deficient Knee

Abstract

Purpose: To document the diagnostic accuracy and steps for sequential arthroscopic exploration of ramp lesions-peripheral tear within 4 mm of meniscocapsular junction of medial meniscus-associated with anterior cruciate ligament (ACL) injury.

Methods: This was a prospective consecutive study of 195 primary ACL reconstructions with arthroscopic exploration for ramp lesion in 4 steps: (1) standard exploration through the anterolateral portal, (2) through the intercondylar space using a 30° arthroscope, (3) through the intercondylar space using a 70° arthroscope, and (4) after creation of a posteromedial portal. Acute (<3 months) and chronic case (>3 months) groups were compared, and the sensitivity and specificity of magnetic resonance imaging (MRI) were assessed.

Results: Overall, 50 patients (26.6%) were confirmed as having a ramp lesion. After step 1, only 19 cases (38%) were identified as a ramp lesion. After step 2, 24 cases (48%) were found, and the sensitivity of step 2 was estimated at 48%. After step 3, an additional 26 cases (52%) were identified. No more additional cases of ramp lesion were found after step 4. There were statistically significant differences between steps 2 and 3 (P = .001), but no differences between steps 1 and 2, or steps 3 and 4. Although there were no statistical differences in overall prevalence for acute (28/128, 21.8%) and chronic (22/67, 32.8%) groups (P = .136), the incidence of ramp lesion confirmed through the standard portal approach was found to be significantly correlated with chronic group (odds ratio: 2.95, P = .023). The sensitivity and specificity of preoperative MRI were 84% and 95.17%.

Conclusions: Many ramp lesions could not be diagnosed through the standard portal and intercondylar space using a 30° arthroscope. Posteromedial inspection using a 70° arthroscope has improved the diagnostic accuracy for ramp lesion without direct exploration through the posteromedial portal. Care should be taken to identify ramp lesions when ACL reconstruction is performed.

Level of evidence: Level I, diagnostic study of consecutive patients.