Meniscus is a wedge shaped fibro-cartilaginous tissue that separates thigh bone (femur) from shin bone (tibia). Each knee joint has a medial meniscus and a lateral meniscus. Meniscus acts as “shock absorbers” between thigh bone and shin bone. As we walk, run, and jump the knee absorbs these tremendous forces.
The wedge shape assists in rotational stability. The medial meniscus is much less mobile than the lateral and it cannot as easily accommodate to abnormal stress. This may be why meniscal lesions are more common on the medial side than the lateral side.
Role of meniscus:
- Improving articular congruency and increasing the stability of the joint.
- Controlling the complex rolling and gliding movements of the joint, and
- Distributing load during movement
In adult people, meniscal tears are usually the result of trauma, contact sports like soccer players are more likely to suffer from meniscal injuries.
Even in the absence of injury, there is gradual stiffening and degeneration of the menisci with age, so splits and tear are more likely in elderly life, particularly if there is an associated arthritis.
The meniscus consists mainly of circumferential fibers held by a few radial strands. It is, therefore more likely to tear along its length than across its width.
Mechanism of injury:
The split is usually initiated by a rotational grinding force which occurs when the knee is flexed and twisted while taking weight. Hence its common in contact sports like soccer, rugby etc.
In 75%, the split is vertical along the length of meniscus. If the separated fragment remains attached to the ends (anteriorly and posteriorly), the lesion is called “bucket handle tear”. The torn portion at times is displaced towards the centre of the joint and causes jamming between the thigh bone and shin bone (a blockage to extension) often referred as “locking”. If the tear appears at one of the end edge of meniscus like a tongue, if it is anteriorly it is known as an “anterior horn tear “ and if posteriorly it is known as a “posterior horn tear”.
Horizontal tear are less common and are result of minor repetitive trauma. These tear are degenerative in nature ate mostly associated with meniscal cysts.
Most of the portion of meniscus is avascular (white zone) and spontaneous repair doesn’t occur unless the tear is in the outer third (red zone), which is vascularized from the attached synovium and capsule.
The loose fragment acts as mechanical irritant and can give rise to recurrent synovial effusion and in some cases, secondary osteoarthritis.
The patient is usually a young person who sustained a twisted injury to the knee while playing.
Pain (usually on the medial side) is often severe and further activity is avoided.
Occasionally the knee is locked in partial flexion.
Almost invariably swelling appears some hours later, or perhaps the following day.
With rest the initial symptoms subsides only to recur periodically after trivial twists or strains.
Sometimes the knee “gives way” spontaneously and this is again followed by pain and swelling.
In patients aged above 40 years the initial injury may be unremarkable and the main complaint is of recurrent “giving way” or “locking”.
On examination, the knee may be held in slight flexion and there is often slight effusion. In long standing cases, the quadriceps will be wasted. Tenderness is localized to the joint line, in most patients on the medial side. Flexion is often full but extension is often slightly limited.
Apley’s grinding test and McMurry’s test can be used to identify a meniscal tear.
Plain x-rays are usually normal. MRI is the most reliable method of confirming the diagnosis. Arthroscopy, has the advantage that, if a lesion is identified it can be treated at the same time.
A small meniscus tear, or a tear in the red zone, will usually respond quickly to physiotherapy treatment.
Researchers have discovered that if the strengthening of leg muscles is done adequately, the bone stresses reduces and knee becomes more dynamically stable. This can be achieved through physiotherapy treatment.
Aims of physiotherapy treatment:
- Control pain and inflammation.
- Achieve full joint range of motion.
- Strengthening of muscles around knee: especially quadriceps and hamstrings.
- Strengthening of lower limb muscles: calves, hip and pelvis muscles.
- Improve patello-femoral alignment.
- Proprioception and balance training.
- Prevention of reoccurrence
Meniscal injuries are commonly associated with other knee injuries, which need to be treated in conjunction with your meniscal tear.
Meniscal tear commonly takes six or eight weeks to fully heal. As mentioned previously, some meniscal tears may require surgery.
It is important to avoid activities and exercises that place excessive stress on meniscus and further delay healing. In some cases, physiotherapist may advise partial on no weight bearing. In such instances, crutches may be recommended.
Most surgeons will recommend a few weeks of physiotherapy treatment prior to contemplating surgery.
Benefits of pre-operative physiotherapy:
- In most cases patient shows great recovery and is successfully rehabilitated without surgery.
- Strengthening the knee for better preparation of post-operative rehabilitation.
Surgery is usually performed arthroscopically to either resect (remove) the torn fragment or repair (stitch) a tear in the outer zone.
Post-Surgical Physiotherapy for Meniscal surgery
Resected Meniscal Tears
Physiotherapy rehabilitation for resected meniscal tears is usually aggressive, targeting early return to function. Patient is progressed through rehabilitation as pain and swelling subsides. These patients normally return to function within 3 to 6 weeks.
Rehabilitation after a meniscus repair usually differs from a resected surgery due to healing time required to heal up the stitched meniscus. Patient is on non-weight bearing for 4 to 8 weeks to allow the meniscus to heal before commencing weight-bearing exercises.
Physiotherapy rehabilitation should focus on early mobilization of the knee joints and strengthening of quadriceps, hamstrings and leg muscles.
Treatment guidelines will be similar to the non-operative approach taking into consideration the findings and operative procedures performed.
For more specific information, consult physiotherapist at PAIN FREE PHYSIOTHERAPY CLINIC.