Meniscus Injury

What is a Meniscus?

• The menisci are crescent-shaped fibrocartilaginous discs located between the distal femoral condyles and proximal tibial plateau

Function of the Meniscus

• Distributes stress across the joint surface by providing a larger area of contact

• Deepens the tibial plateau for greater stabilization of the knee

• Acts as a shock absorber to absorb the forces resulting from weight-bearing and movement

• Provide lubrication and nutrition to the synovial cavity

What is Lateral Meniscus Injury?

• The lateral meniscus is loosely attached anteriorly and posteriorly to the joint capsule and allows mobility

• Due to the greater degree of mobility of the lateral meniscus, it is less vulnerable to injury

• Lateral meniscal injuries are less common than medial meniscal injuries

What is Medial Meniscus Injury?

• The medial meniscus is firmly attached to anteriorly and posteriorly to the joint capsule

• Medial meniscal tears are more common than lateral meniscal injuries– Occur 2-5 times more often

Causes of Meniscus Injuries

• Can result from activities involving pivoting or rotational movements– i.e. pivoting, sudden stops and turns, kneeling, deep

squatting, heavy lifting

• Tears in the meniscus of the knee are commonly due to sports-related injuries

• Degenerative changes of the knee can contribute to a torn meniscus

• Meniscal tears may be associated with anterior cruciate ligament tears– The instability of the knee increases the likelihood of

a meniscal tear over time

Patient population affected by Meniscal Injuries:

• Meniscal injury is one of the most common knee injuries seen in people

• Common in adolescents and adults; uncommon children– Incidence increases with age

• Patients tend to be older and less active, often with osteoarthritic changes present

• Meniscal tears are more common in adolescent males than females

• Common in patients who participate in high impact sports– i.e. soccer, basketball, wrestling, football, gymnastics,

skiing

Risk Factors

• Age• History of previous knee injuries• Participation in sports activities that

involve pivoting movements • High body mass index

Diagnosis

• Plain radiography can be helpful in the management of meniscal tears

• Gold standard for diagnosis is arthroscopy

• MRI is used as an alternative for diagnosis, but does not commonly identify meniscal tears

• CT scans can be used based on the situation, but are not commonly used for diagnosing meniscal tears

Clinical Presentation

• Pain and tenderness at joint line• Effusion• Swelling• A snapping or popping sensation heard at

time of injury• Intermittent locking or catching of the joint• Pain with weight bearing

• *Cardinal sign of meniscal tears is pain and joint line tenderness*

Examination

• The physical examination should begin with an assessment of the patient’s stance and gait.

• Assessment of the patient in both supine, seated, and prone positions should also be included in the physical examination.

• The knee examination should begin with inspection to assess for quadriceps atrophy, joint line swelling and tenderness. Gentle passive range of motion should be performed to assess for any asymmetry or loss of extension.

• A functional weight-bearing examination should be conducted to distinguish meniscal pathology from patellofemoral problem.

Examination findings

• Decreased range of motion• Joint line tenderness• Swelling• Effusion• Positive McMurray’s Test• Positive Apley Test• Positive Thessaly Test

McMurray’s Test

• The patient is placed in a supine position with the knee stabilized.

• The therapist rotates the tibia and then extends the knee while applying a varus or valgus load.

• A positive test is noted by a painful click or pop during mid-extension indicating a meniscal tear

Apley Test

• The patient is positioned in a prone position with the knee flexed to 90 degrees

• The therapist applies an axial rotational load against the tibial plateau and the femoral condyles

• A positive test is noted by pain or palpable click

Thessaly Test

• The patient is positioned in a supported single leg stance while rotating their body in both directions at 5 degrees and 20 degrees

• A positive test is noted by pain

Goals of Treatment

• Reduce inflammation• Reduce pain• Increase muscle strength and

endurance• Restore joint stability• Restore movement and function

Non-operative Treatment

Physical Therapy

• The physical therapy rehabilitation program is designed to improve function as well as strength and motion– Involves the following components:

• Proprioception• Strength• Flexibility• Endurance• Agility

• Exercises incorporate both weight-bearing and non-weight bearing activities to dynamically maximize joint stability

Modalities

• Immobilization of knee – Use of crutches to assist with minimizing the

amount of weight bearing • Recommended to be used until the patient is pain-free

– RICE therapy (rest, ice, compression, elevation) • Used to control pain and swelling after an injury

• Arch supports– Arch supports or shoe inserts can help distribute

fore more evenly around the knee and decrease stress on certain areas of the knee

Pharmacology

• There are various forms of medications that can be used to help control the level of pain–NSAIDs– Acetaminophen– Oxycodone

Operative Treatment

Meniscectomy

• It is a minimally invasive surgical procedure that involves the treatment of damage to the meniscus in the knee

• Characterized as partial or complete meniscal removal is done through an arthroscope

• This type of surgery is reserved for cases in which the symptoms are persistent and limit activity

• The gold standard in the diagnosis of meniscal pathology

Meniscal Repair

• This is the preferred method for salvaging the meniscus

• This method is used for tears that are amendable to repair in which the meniscus is secured to the capsule surgically

Meniscal Replacement

• Replacing the damaged meniscus with tissue from a donor helps restore normal knee structure and protect the remaining joint surfaces of the knee.

What is the outcome of treatment?

• Refer to orthopedic surgeon if condition is severe enough to require surgery

• Physical therapy– Improve lower extremity strength– Improve lower extremity flexibility

• Prognosis: Good

Prognosis

• Dependent on age of individual, extent of injury, and treatment used– A younger individual with a small tear in a

vascular, peripheral region of the meniscus who is managed with conservative treatment may have complete healing of the meniscus with excellent outcome.

– An older individual with degenerative disease who required meniscectomy may progress to severe degenerative disease and may eventually require joint replacement

Resources

• Ferri: Ferri’s Clinical Advisor 2011, 1st Edition. Copyright © 2010 Mosby, An Imprint of Elsevier.

• Lazoff, Marie. First Consult. Elseiver Inc. Copyright © 2011

• Marx: Rosen’s Emergency Medicine, 7th Edition. Copyright © 2009 Mosby, An Imprint of Elsevier.

• DeLee: DeLee and Drez’s Orthopaedic Sports Medicine, 3rd Edition. Copyright © 2009 Saunders, An Imprint of Elsevier.