Meniscal tears

Meniscus tear is the prevalent knee injury in young, active athletes and elderly people. There are medial and lateral meniscus which both are C or u shaped, hydrate and fibrocartilaginous soft tissue in the knee joint. They are a part of meniscus-meniscal ligament complex with surrounding ligamentous structures which are menisco-tibial, menisco-femoral, menisco-patellar and intermeniscal ligaments.

Only peripheral 10-30% portion is vascularized in the second decennium. *2 Thus, if tears are seen in outer 10-30% of the portion, it can heal by itself.   

The roles of meniscus

• Shock absorption
• Load bearing
• Joint stability
• Lubrication in the joint
• Protection of articular cartilage

Aetiology *3

• 60 years old +
• Male >female
• Occupations that require kneeling, squatting and climbing up and down
•  Soccer and rugby players
• ACL surgery or reconstruction without rehabilitation

*Medial meniscal tear is more prevalent than lateral one while medical meniscus is less mobile than lateral meniscus. According to research, 56% of all tears are posterior horn of medial meniscus, 2% is anterior portion of medial meniscus and 16 % is lateral meniscus tear. *4

Signs and symptoms

• Pain in the knee
• Swelling
• Popping sound when injured
• Restricted knee ROM
• Catching and locking sensation in the knee

Special tests for Meniscus tear

• Apley’s test
• McMurray test
• Thessaly Test
• Joint Line Tenderness Palpation

*Although these are known as special tests for meniscal tear, the accuracy of them are poor. *5

Treatment *6

• Strengthening exercise (cycling with quads exercise)
• Meniscectomy (risk of osteoarthritis)  

Classification of meniscal tears

The ISAKOS classification of meniscal tears provides sufficient interobserver reliability for pooling of data from international clinical trials designed to evaluate the outcomes of treatment for meniscal tears. *7

1. Tear depth: partial or complete tear
2. Rim width (Location):

*Zone 1: Tears with a rim of less than 3mm

*Zone 2: Tears have a rim width 3-5mm

*Zone 3: Tears have a rim width of more than 5mm

• Radical location: Posterior, mid body or anterior
• Central to the popliteal hiatus: A tear of lateral meniscus that extends partially or completely in front of the popliteal hiatus should be graded as central to the popliteal hiatus
• Tear pattern: Longitudinal-vertical, horizontal, radial, vertical flap, horizontal flap and complex
• Quality of tissue: Non-degenerative, degenerative or undetermined
• Length of tear in MM: The length of a radical tear is the distance the tear extends into meniscus
• Indicate the amount of meniscal tissue that has been excised
• What percentage of medial meniscus was excised?

*This is the classification sheet for orthopaedic surgeon. However, this may be helpful for allied health practitioner when patients come in with MRI image results as to meniscus injury in order to perform exercise or treatment.  

Reference  

1. Mahmut Nedim Dorai, Onur Bilge, Gazi Huri, Egemen Turhan and Rene Verdonk Modern treatment of meniscal tears EFORT open Reviews 2018 3 (5): 260-268
2. Petersen W, Tillmann B. Age-related blood and lymph supply of the knee menisci. A cadaver study. Acta Orthop Scand 1995; 66 :308-312
3. Snoeker BAM, Bakker EWP, Kegel CAT, Lucas C. Risk factors for meniscal tears: a systematic review including meta-analysis. J Orthop Sports Phys Ther 2013;43:352-367.
4. Fox MG. MR imaging of the meniscus: review, current trends, and clinical implications. Magn Reson Imaging Clin N Am. 2007;15(1):103-123
5. Smith BE, Thacker D, Crewesmith A, Hall M. Special tests for assessing meniscal tears within the knee: a systematic review and meta-analysis. Evid Based Med 2015;20:88-97
6. Mordecai SC, Al-Hadithy N, Ware HE, Gupte CM. Treatment of meniscal tears: an evidence based approach. World J Orthop2014;5:233-241
7. Allen F Anderson The ISAKOS Classification of Meniscal Tears ISAKOS Newsletter 2010 11-13