II. Epidemiology
- Most common Knee Injury
III. Anatomy: Menisci
- Meniscus cushions forces between femur and tibia
- Fibrocartilaginous C-shaped (semilunar) objects
- Medial meniscus (90%)
- Less mobile than lateral meniscus
- Lateral meniscus (10%)
- Medial meniscus (90%)
IV. Mechanism: Twisting injury
- Fixed tibial rotation with knee flexion or extension
V. Associated injuries
- Anterior Cruciate Ligament Tear (33% of cases)
VI. Symptoms
- Twisting injury to knee while weight bearing
- Initial tearing, painful Sensation felt
- Pain localized to affected meniscus
- Buckling Sensation
- Gradual onset of effusion following injury
- Provocative
- Stair climbing or stair descent
- Squatting
- Knee Locking
- Intermittent Locking (common)
- Locked Knee Syndrome (uncommon)
- May result in persistent inability to flex and extend knee
- Meniscus Bucket Handle Tear refers to torn meniscus fragment that flips into intercondylar notch
- Prevents knee range of motion, and results in difficult ambulation
- May be associated with Anterior Cruciate Ligament Tear
- Indicates early MRI and orthopedic Consultation
VII. Signs
- Joint effusion
- McMurray's Test positive
- Apley's Compression Test positive
- Apley's Distraction Test negative
- Knee Bounce Test positive
VIII. Imaging
-
Knee XRay
- Initial Knee Injury evaluation for Fracture
-
Knee MRI
- Diagnosis of meniscal tear
IX. Management: Conservative
X. Management: Arthroscopy
- Indications
- Irreducible locking (see Locked Knee Syndrome above)
- Mechanical symptoms (locking or catching)
- Refractory meniscus symptoms (e.g. pain) despite above management
- Efficacy arthroscopy, meniscectomy and Debridement
- No longterm benefit in middle aged and older patients (with or without Knee DJD)
- No significant improvement in knee catching or locking in those with meniscal tear
- Exercise therapy is preferred
- Sihvonen (2016) Ann Intern Med 164(7): 449-55 [PubMed]
- Thorlund (2015) BMJ 350:h2747 [PubMed]
- Khan (2014) CMAJ 186(14):1057-64 [PubMed]
XI. Prognosis: Predictors of Best Longterm Outcomes
- Acute, non-degenerative meniscal tear
- Age <35 years old
- Vertical meniscal tear
- No cartilage injury
- Intact meniscal rim after meniscectomy
XII. Complications
XIII. References
- Mercier (1995) Practical Orthopedics, Mosby, p. 217-9
- Rashidzada (2020) Crit Dec Emerg Med 34(9): 16-7
- Smith (1995) Am Fam Physician 51(4): 799-806 [PubMed]