Meniscal tears associated with anterior cruciate ligament injury

Purpose To investigate the frequency of meniscal tear and the location of tear associated with anterior cruciate ligament (ACL) injury. We studied 549 patients (552 knees) who were diagnosed with ACL injury by arthroscopy at our center between January 2006 and March 2014 (8 years and 3 months). The subjects comprised 289 males and 263 females ranging in age from 13 to 66 (mean 26.1) years. The cause of injury was sports-related in 89.1 %, and the mean interval from injury to initial arthroscopy was 23 months. The patients were divided into two groups: arthroscopy performed within 8 weeks after injury (acute group; 256 knees) and more than 8 weeks after injury (chronic group; 296 knees). Frequency of meniscal tear and location of tear were compared between two groups. The incidence of meniscal tear diagnosed by arthroscopic examination was 79.2 % (437 of 552 knees) in all subjects; 72.7 % (186 of 256 knees) in acute group and 84.8 % (251 of 296 knees) in chronic group, and was significantly higher in chronic group. Regarding the locations of meniscal tears, in acute group (186 knees), medial meniscal tear only was found in 20 knees (10.8 %), lateral meniscal tear only in 129 knees (69.4 %), and bilateral (including medial and lateral) meniscal tears in 37 knees (19.9 %). In chronic group (251 knees), medial meniscal tear only was found in 62 knees (24.7 %), lateral meniscal tear only in 85 knees (33.9 %), and bilateral meniscal tears in 104 knees (41.4 %). Lateral meniscal tear was commonly associated with acute ACL injury, while medial meniscal tear with chronic ACL injury. Bucket handle tear was observed in 25 knees (medial: 17 knees, lateral: 8 knees) in acute group, and 81 knees (medial: 69 knees, lateral: 12 knees) in chronic group, and was more common in the chronic group. The incidence of meniscal tear associated with ACL injury is higher in chronic cases; the number of medial meniscal tears is particularly high, many of which require meniscectomy. Early ACL reconstruction is recommended also for the prevention of secondary meniscal tear.