By Greg Louie, DPT
The menisci lie between the tibia and femur. They stabilize the knee into flexion and extension, assist in joint lubrication and nutrition, and distribute compressive forces to reduce stress on the articular cartilage with load-bearing and load transmission.(1) Meniscal tears are quite common,the mean annual incidence of meniscal injuries are 66 for every 100,000 individuals.(2)
There are two classifications of meniscal tears: traumatic and degenerative. For a meniscus tear to classified as traumatic, the meniscus must be healthy and there must be an injury to the knee as a result of a forced movement.(3) These types of tears are higher amongst young adults because of an increased percentage of this population participating in high-level activities and sports.(4) A forced twisting movement with the knee bent is the common mechanism of injury for traumatic lesions. Degenerative tears occur in the absence of trauma and result from deterioration of the meniscus from abnormal loading forces to the knee.(3) Individuals with a body mass index greater than 25, those who are older then 60, and those who work in jobs requiring increased kneeling, squatting, and stair climbing are at a significantly higher risk for degenerative meniscal tears.(4)
Meniscus injures are often accompanied by other ligamentous injuries of the knee.(3) A combination of injury to the meniscus, medial collateral ligament, and the anterior cruciate ligament is known as the unhappy triad of the knee.(5)
In the United States, partial meniscectomies are the most common orthopedic surgical procedure(6) but does this mean everyone with a torn meniscus should opt for surgery? Several studies have found that surgery is not always necessary and that physical therapy should be considered prior to surgery. Sihvonon and associates found no difference in partial menisectomy compared to sham surgery.(7) Katz and colleagues found no difference in outcomes with arthroscopic partial meniscectomy combined with physical therapy compared to physical therapy alone.(8) Surgery should be considered as a last resort when all other interventions (including physical therapy) have failed.
A physical therapist will assess the severity of the tear and provide interventions to control the pain, inflammation, and swelling. As the knee beings to heal, they can help you regain full range of motion, get you back walking pain free, and build strength and coordination to prevent reinjury.
Blog post written by Greg Louie, DPT Student from University of St. Augustine. At the time of publishing Greg was in a clinical rotation at Catz PTI. Follow him on Instagram @sportsperformancerehab
References:
1. Makris EA, Hadidi P, Athanasiou KA. The knee meniscus: structure-function, pathophysiology, current repair techniques, and prospects for regeneration. Biomaterials. 2011;32(30):7411-7431.
2. Hede A, Jensen DB, Blyme P, et al. Epidemiology of meniscal lesions in the knee. Acta Orthop Scand. 1990; 61:435–437.
3. http://www.physio-pedia.com/Meniscal_Lesions
4. Snoeker BA, Bakker EW, Kegel CA, Lucas C Risk factors for meniscal tears: a systematic review including meta-analysis. J Orthop Sports Phys Ther 43: 352–367. 2885
5. Sbourne K, Nitz P. The O’Donoghue triad revisited. Combined knee injuries involving anterior cruciate and medial collateral ligament tears. Am J Sports Med. 19(5):474–7.
6. Englund M, Guermazi A, Gale D, et al. Incidental meniscal findings on knee MRI in middle-aged and elderly persons. N Engl J Med. 2008; 359:1108-1115.
7. Sihvonen R, Paavola M, Malmivaara A, et al. Arthroscopic partial meniscectomy versus sham surgery for a degenerative meniscal tear. N Engl J Med. 2013; 369(26): 2515–24.
8. Katz JN, Brophy RH, Chaisson CE, et al. Surgery versus physical therapy for a meniscal tear and osteoarthritis. N Engl J Med. 2013; 368:1675-1684
Chris Butler Sports PT 