The epidemiology of meniscal lesions in stable knee has been a focus of study, but exact topography is not clearly known. Tear patterns are thought to differ between pathologies and the difference between a traumatic and a degenerative pattern is not always easy to draw. In 2010, ISAKOS designed a questionnaire to standardize assessment. The main objective of present study was to detail the precise topography and type of surgical meniscal patterns (i.e., that were operated on) in stable knee. Secondary objectives were to assess the relationship of tear pattern and cartilage lesions in the tibiofemoral compartment, and to analyze age at onset.

The study hypotheses were that tear pattern correlates with cartilage lesions, and that mean age differs according to tear pattern, with younger onset of vertical tears, in surgery@ patients.

Data collection for this descriptive epidemiological study was prospective, on systematic ISAKOS questionnaire. 1424 isolated meniscal tears in stable knee, operated on between 2010 and 2017, were included: 253 lateral meniscus (LM), and 1171 medial meniscus (MM). Mean age at surgery was respectively 36 and 47 years.

The most frequent tear pattern was vertical (39% in LM, 38% in MM). The more frequent locations were posterior+midpart and midpart (22% each) in LM, and posterior in MM (56%). Tears were mainly peripheral (zone 1) in LM (46%), and zone 2 in MM (46%). Mean age in medial vertical tears was 43±14 years, significantly lower (p<0.001) than in other types. Meniscal tear pattern correlated significantly with medial tibiofemoral cartilage lesion (p<0.001).

The present study described the precise topography of isolated meniscal tears in stable knee in a large sample, using the ISAKOS questionnaire. The study hypotheses were confirmed for the medial but not the lateral meniscus.

III; well-conducted non-randomized prospective comparative study.