Meniscus Injury
Definition
A meniscus injury involves a tear of the C-shaped fibrocartilaginous pads that act as shock absorbers and stabilisers between the femur (thigh bone) and the tibia (shin bone) in the knee joint (1, 2). These injuries can be acute, resulting from trauma, or degenerative, arising from age-related wear and tear.
Epidemiology
In Malaysia, while specific prevalence data for isolated meniscus tears is not readily available, data on associated injuries provide some context. A study on Anterior Cruciate Ligament (ACL) reconstructions among Malaysian athletes between 2015 and 2020 found that a significant 61.1% of cases had a concomitant meniscus injury (3).1 General knee pain, a primary symptom of meniscal injury, is also common.2 A Malaysian study on older adults reported a knee pain prevalence of 33.3%, with notable ethnic differences: crude prevalence was highest among Malays (44.6%), followed by Indians (31.9%) and Chinese (23.5%) (4). This may be partly attributed to lifestyle factors such as frequent squatting or sitting on the floor, which increases stress on the knee joint (4).
Globally, meniscus tears are one of the most common knee injuries. The incidence of acute tears is highest in active individuals aged 10-45, often linked to sports participation (5). Degenerative tears are more prevalent in individuals over 40 and are strongly associated with the cumulative stress of daily activities and early osteoarthritic changes (6).
Pathophysiology
The mechanism of a meniscus injury is typically a shear force created by rotation of the femur on a fixed, weight-bearing tibia (7). In younger individuals, this is commonly an acute twisting or pivoting motion, such as a sudden change in direction while running.3 This force can cause a vertical or radial tear in the healthy, resilient meniscal tissue (5).
In older individuals, the meniscus becomes less elastic and more brittle due to degenerative changes. Tears can occur with minimal trauma, such as rising from a squat or stepping awkwardly (6). These are often horizontal or complex tears.4 The location of the tear is critical for healing potential; the outer third of the meniscus (the "red zone") is vascularised and can heal, whereas the inner two-thirds (the "white zone") are avascular and have a very limited capacity for repair (8).5 The medial meniscus is more frequently injured than the lateral meniscus because it is more firmly attached to the joint capsule and tibia, making it less mobile and more susceptible to being trapped and torn during rotational movements (1).6
Clinical Presentation
The classic presentation involves a patient reporting knee pain after a specific twisting injury, often accompanied by a "pop" or tearing sensation at the time of the event (9).
Diagnostic Clues:
The triad of joint line tenderness, a history of mechanical locking or catching, and a positive McMurray test is highly suggestive of a meniscal tear (10).
Common Symptoms (>50%):
Knee pain, typically localised to the medial or lateral joint line (~90%) (1, 2)7
Delayed swelling and stiffness, developing over 24-48 hours (9)
Mechanical symptoms: clicking, catching, or a sensation of the knee "giving way" (1, 9)8
Less Common Symptoms (10-50%):
Locking of the knee joint (inability to fully extend or flex the knee), which occurs when a displaced fragment of the meniscus blocks joint movement (2).9
Restricted range of motion, particularly at the extremes of flexion and extension (10).10
⚠️ Red Flag Signs & Symptoms:
A locked knee that cannot be passively unlocked requires urgent orthopaedic assessment.11 This suggests a displaced bucket-handle tear, which can cause further chondral damage if not addressed promptly (10).
Associated signs of ligamentous injury (e.g., significant instability after trauma), suggesting a more complex injury like the "unhappy triad" (ACL, MCL, and medial meniscus tear) (5).
Signs of a septic joint (fever, erythema, severe warmth), which is a crucial differential to exclude.12
Complications
Mechanical: Persistent locking or catching can impede daily activities.13
Muscular: Quadriceps wasting and weakness can develop secondary to pain and disuse, leading to functional instability.
Long-Term: A meniscectomy (surgical removal) or an unrepaired tear significantly alters joint mechanics, increasing contact stress on the articular cartilage.14 This is a major risk factor for the premature development of knee osteoarthritis, with radiographic changes often visible within 5-10 years post-injury (11, 12).
Prognosis
The prognosis for a meniscus injury depends on the tear type, its location (vascularity), the patient's age and activity level, and the chosen treatment.15 With appropriate management, many patients return to their previous level of function (1). Tears in the vascular outer zone have a good potential for healing if repaired.16 However, a partial or total meniscectomy, while providing symptomatic relief, is associated with a high long-term risk of osteoarthritis (12). A Malaysian study on meniscal surgery outcomes found successful results in 80% of meniscal repairs but only 51.7% in partial meniscectomies, highlighting the importance of preserving meniscal tissue where possible (13).
Differential Diagnosis
Anterior Cruciate Ligament (ACL) Tear: This is a key differential, especially after a significant pivoting injury, due to the shared mechanism of trauma and symptoms like a "pop," swelling, and instability. However, ACL tears typically present with a large, immediate haemarthrosis (swelling within hours) and significant instability during clinical testing (e.g., positive Lachman or anterior drawer test), which are less prominent in isolated meniscal injuries (5).17
Patellofemoral Pain Syndrome: Consider this, particularly in younger patients without a clear history of a single traumatic event. The pain is typically anterior (behind the kneecap) and is exacerbated by activities like climbing stairs, squatting, or prolonged sitting (the "theatre sign"). It is distinguished by the absence of true mechanical locking and joint line tenderness specific to the menisci (14).
Knee Osteoarthritis (Degenerative Joint Disease): In older patients (>50 years) without an acute injury, this is a primary differential. It is often responsible for degenerative meniscal tears. The pain is typically a dull ache, worse with activity and relieved by rest, with associated morning stiffness that improves with movement. Distinguishing features include the presence of crepitus on examination and characteristic findings on a plain X-ray (e.g., joint space narrowing, osteophytes), which are absent in acute traumatic tears in young patients (11).
Investigations
The diagnosis of a meniscal tear is primarily clinical, with imaging used for confirmation and surgical planning.
Immediate & Bedside Tests
Clinical Examination: A thorough knee examination is the most important immediate step to assess for joint line tenderness, effusion, range of motion, and ligamentous stability (the action), which helps localise the injury and rule out associated ligament tears that require different management pathways (the rationale). Special provocative tests like the McMurray and Apley tests can be performed to elicit pain or a click over the torn meniscus.18
Diagnostic Workup
First-Line Investigations: "A plain radiograph (X-ray) of the knee (weight-bearing anteroposterior, lateral, and skyline views) is the initial imaging modality. It is essential for excluding bony injuries like fractures or loose bodies and for assessing for signs of osteoarthritis in older patients (the rationale), which helps guide whether the tear is acute or degenerative and influences the treatment strategy (the action)."19
Gold Standard: "The definitive non-invasive diagnosis is established with a Magnetic Resonance Imaging (MRI) scan. It provides detailed visualisation of the menisci, ligaments, and articular cartilage (the rationale), allowing for precise characterisation of the tear type, location, and severity, which is crucial for surgical planning (the action) (1, 10)."20
Monitoring & Staging
Diagnostic Arthroscopy: While MRI is the gold standard for diagnosis, arthroscopy is the gold standard for both diagnosis and treatment. It allows direct visualisation and probing of the meniscus to assess tissue quality and tear stability (the rationale), enabling the surgeon to perform a repair or meniscectomy in the same procedure (the action) (2).
Management
Management Principles
The management of a meniscus injury is tailored to the patient and tear characteristics, focusing on relieving symptoms, restoring knee function, and preserving as much meniscal tissue as possible to prevent long-term degenerative changes (1, 10).21
Acute Stabilisation (The First Hour)
For an acute traumatic presentation, initial management follows the PRICE principle:
Protection: "Advise the use of crutches to offload the knee if weight-bearing is painful (the action), which prevents further mechanical irritation of the torn fragment and reduces pain (the rationale)."
Rest: "Cease the offending activity and limit knee flexion and twisting motions (the action) to allow the initial inflammatory response to subside (the rationale)."22
Ice: "Apply cold packs to the knee for 15-20 minutes every 2-3 hours (the action).23 This induces vasoconstriction, which helps to limit swelling and provides analgesia (the rationale)."
Compression: "Use an elastic bandage to apply compression to the knee (the action), which helps control the development of an effusion (the rationale)."
Elevation: "Keep the leg elevated above the level of the heart when resting (the action) to facilitate venous and lymphatic drainage, thereby reducing swelling (the rationale)."24
Analgesia: "Prescribe simple analgesics like Paracetamol or a short course of NSAIDs (e.g., Ibuprofen 400mg TDS or Naproxen 500mg BD, if no contraindications) (the action) to manage pain and inflammation, improving patient comfort and allowing for early mobilisation exercises (the rationale)."25
Definitive Therapy
The choice between conservative and surgical management depends on symptoms (especially locking), tear type and location, and patient factors.
Conservative Management (Non-surgical)
This is indicated for small, stable tears in the vascular zone, degenerative tears without mechanical symptoms, and in patients who are not surgical candidates.
Physical Therapy: "A structured physiotherapy programme is the cornerstone of non-operative treatment.26 It focuses on strengthening the quadriceps and hamstring muscles (the action) to provide dynamic stability to the knee, compensating for the compromised meniscus (the rationale). The regimen also includes exercises to restore full range of motion."27 (2, 10)
Surgical Management
This is indicated for large, complex tears, tears causing mechanical locking, bucket-handle tears, and for patients who fail to improve with conservative management. The procedure is typically performed arthroscopically.
First-Line Treatment (for repairable tears): Meniscal Repair. "For longitudinal tears in the vascular 'red zone' in younger patients, an arthroscopic meniscal repair is the preferred treatment. This involves suturing the torn edges together (the action) to promote healing and preserve the entire meniscus, which is critical for maintaining normal knee biomechanics and preventing long-term osteoarthritis (the rationale)." (10, 13)28
Alternative Treatment: Partial Meniscectomy. "For complex tears, tears in the avascular 'white zone', or degenerative tears not amenable to repair, an arthroscopic partial meniscectomy is performed.29 This involves resecting only the unstable, torn fragment of the meniscus and smoothing the remaining rim (the action) to alleviate mechanical symptoms like locking and catching (the rationale). The goal is to preserve as much functional meniscal tissue as possible." (2, 12)
Supportive & Symptomatic Care
Analgesia: Continue as needed for post-operative or chronic pain.
Rehabilitation: Post-operative physiotherapy is crucial for a successful outcome, with protocols varying based on whether a repair (which requires a period of protected weight-bearing) or a meniscectomy was performed.
Key Nursing & Monitoring Instructions
Monitor and document neurovascular status of the affected limb post-operatively.
Strictly adhere to post-operative weight-bearing instructions (e.g., non-weight bearing for 4-6 weeks after meniscal repair).
Administer prescribed analgesia and monitor for effectiveness.30
Educate the patient on the importance of elevation and ice therapy to control swelling.
Inform the medical staff if there is excessive pain not controlled by analgesia, significant swelling, or any signs of calf pain or swelling (to rule out DVT).
Long-Term Plan & Patient Education
The long-term plan involves completing the rehabilitation programme to regain strength and function.31 Patients should be educated about the increased risk of future knee osteoarthritis, especially after a meniscectomy. Key educational points include maintaining a healthy weight to reduce load on the knee, avoiding high-impact activities if symptomatic, and continuing with strengthening exercises to support the joint.32 Follow-up with the orthopaedic surgeon is typically scheduled at 2 weeks, 6 weeks, and 3-6 months post-operatively to monitor progress.
When to Escalate
A house officer should manage the initial presentation with analgesia and PRICE therapy but must know when to seek senior help.
Call Your Senior (MO/Specialist) if:
The patient presents with a locked knee that cannot be reduced.
There is a suspected associated fracture or major ligamentous injury (e.g., ACL/PCL tear).
The patient has signs of a deep vein thrombosis (DVT), such as a swollen, tender, and erythematous calf.
You are uncertain about the diagnosis or management plan.
Referral Criteria:
Refer to the Orthopaedics department for all suspected meniscal tears that are causing significant mechanical symptoms or persistent pain despite initial conservative management.
Urgent referral is required for a locked knee or a knee with significant post-traumatic haemarthrosis and instability.33
References
Sunway Medical Centre. (n.d.). Meniscus Tear. Retrieved July 6, 2025, from https://www.sunwaymedical.com/en/conditions-and-treatments/meniscus-tear
Pantai Hospitals. (n.d.). Meniscus tear. Retrieved July 6, 2025, from https://www.pantai.com.my/medical-specialties/orthopaedic/meniscus-tear
Razak, M. A. A., et al. (2022). Pattern of Anterior Cruciate Ligament Reconstruction (ACLR) among athletes in Malaysia between 2015 and 2020. TMFV, 24(4). (Note: Specific journal link was not available, citation is based on available data).
Tan, P. J., et al. (2019). Ethnic differences in the prevalence, socioeconomic and health related risk factors of knee pain and osteoarthritis symptoms in older Malaysians.34 PLoS ONE, 14(11), e0225075. https://doi.org/10.1371/journal.pone.0225075
Wikipedia. (n.d.). Meniscus tear. Retrieved July 6, 2025, from https://en.wikipedia.org/wiki/Meniscus_tear
Bhan, K. (2020). Meniscal tears. Orthopaedics and Trauma, 34(4), 194-201.
Mordecai, S. C., et al. (2014).35 Treatment of meniscal tears: An evidence based approach. The World Journal of Orthopedics, 5(3), 233–241.
Fox, A. J., et al. (2012). The basic science of human knee menisci: structure, composition, and function. Sports Health, 4(4), 340-351.
Cardone, D. A. (2023). Meniscal injury of the knee. In UpToDate. Retrieved July 6, 2025, from https://www.uptodate.com/contents/meniscal-injury-of-the-knee
American Academy of Orthopaedic Surgeons. (2021). Meniscus Tears. OrthoInfo. Retrieved from https://orthoinfo.aaos.org/en/diseases--conditions/meniscus-tears/
Ministry of Health Malaysia, Malaysian Orthopaedic Association, & Academy of Medicine of Malaysia. (2013). Clinical Practice Guidelines on the Management of Osteoarthritis of the Knee.
Englund, M., & Lohmander, L. S. (2004). Risk factors for symptomatic knee osteoarthritis fifteen to twenty-two years after meniscectomy. Arthritis and Rheumatism, 50(9), 2811-2819.
Vinayaga, P., Amalourde, A., Tay, Y. G., & Chan, K. Y. (2001).36 Outcome of meniscus surgery at University Malaya Medical Centre. The Medical journal of Malaysia, 56 Suppl D, 18–23.
Dixit, S., et al. (2007). Patellofemoral pain syndrome. American Family Physician, 75(2), 194-202.
