Complete Medial Meniscus Posterior Root Tear Without an Extrusion Due to Meniscocapsular Thickening in Sportswoman: A Case Report

Introduction: Medial Meniscus Posterior Root Tear (MMPRT) is the most common type of meniscus root tear attributed to its lesser mobility and higher load. Complete MMPRT is usually accompanied by significant meniscus extrusion (ME) which can be defined as displacement ≥3mm of meniscus from central margin of tibial. Meniscocapsular ligament (ML) is located posteromedially, along with meniscotibial ligament help stabilizing the meniscus. Here, we present an interesting case of sportswoman with complete MMPRT without an extrusion. Case Presentation: a 47-year-old sportswoman initially presented to outpatient clinic complaining right knee pain over 2 months especially when squatting. Her BMI is 20.6 and Physical examination revealed a joint effusion and tenderness at deep flexion. Palpation on medial joint line was unremarkable. Further investigation using MRI showed complete horizontal tear on right medial meniscus posterior. The patient underwent an arthroscopic transtibial pullout repair (ATPR) which intraoperatively we found a complete radial MMPRT without ME and thickening of ML. After surgery, the patient was instructed to wear a knee immobilizer for 2 weeks. Results: The patient had a substantial improvement in pain and functional score after an ATPR procedure. Discussion: Prevalent risk factors of MMPRT include age ≥50, female sex, BMI ≥25, and lower sports activity level (<2/weeks). In this case, the patient’s gender was the only risk factor. Patient was a former running athlete, which led an active lifestyle (sports ≥4/weeks). Recently, she started doing heavy squats and noticed click sound before her complaint. During ATPR, we found no ME despite complete MMPRT. Study by Muzaffar et al. showed that out of total 202 cases of meniscus tears were followed by ME in which 64,26% cases were MMPRT. There were still no studies that linked ML thickening to activity levels. However, study by Grzelak et al. concluded that cruciate ligament might become hypertrophied related to age of training onset and training duration. Therefore, we postulated the thickening of ML, which possibly related to the patient background as a sportswoman, plays role in holding the meniscus. Conclusion: We reported in this case, interestingly ME does not occur possibly due to thickening of ML.