Meniscus Tear
What is a meniscus tear?
The meniscus acts like a shock absorber in the knee joint. It is a C-shaped structure that lies between the femur and tibia. Each knee has 2 menisci, one on the inside (medial) and one on the outside (lateral). The menisci are attached to the tibia bone at the front and the back of the knee. These attachments are referred to as the root attachments of the meniscus.
Meniscal tears can occur from trauma to the knee. They can also occur in the absence of trauma if the quality of tissue in the meniscus has become weak. This typically occurs as patients get older.
Traumatic tears are referred to as acute meniscal tears. These tears can occur in conjunction with other knee injuries—e.g., ACL tears.
Tears in the meniscus due to poor meniscal quality are referred to as degenerative tears.
Menisci can tear in different ways and in different locations. Some of the terms used to describe the tear include radial, bucket-handle, oblique, root, and complex tears. Some tears patterns are less stable than others and may require more urgent surgery such as bucket-handle tears.
When the meniscus is torn, it doesn’t function as a shock absorber as well. This may lead to arthritis within the knee joint over time.
What are the symptoms of meniscus tear?
Meniscal tears can present with pain and swelling within the knee. The pain is usually localised to the inside or outside of the knee, where the meniscal tear is located. Although the pain may result in a limp when you walk, most patients are able to bear weight with a meniscal tear. Most patients struggle with squatting and rapid changes in direction on the affected side.
Sometimes, meniscal tears can present with clicking, catching, or the knee giving way.
With an unstable tear (bucket-handle), the torn meniscus may extrude into the joint and block the patient from fully straightening their knee. This is referred to as a locked knee and must be addressed on a semi-urgent basis.
How do you treat a meniscus tear?
If the meniscal tear is stable, it can usually be managed without surgery. You will be referred to a physiotherapist for strengthening and to restore the range of movement. If a non-operative approach is employed, you will notice a significant improvement in 3 months.
If the meniscal tear is degenerative in nature and there is some pre-existing arthritis within the joint, a steroid injection can be considered. This can help settle the pain associated with the inflamed tissue lining the knee joint. Performing surgery in most cases of degenerative meniscal tears will not help in the long-term.
Sometimes a lubricant (hyaloronic acid) is additionally injected to help replace some of the normal synovial fluid produced by the knee joint.
What does surgery for a meniscus tear involve?
If the meniscal tear is unstable or non-operative management has failed, then surgery can be considered. The surgery either involves repairing the torn meniscus or trimming out the torn portion (meniscectomy). This is performed using keyhole (arthroscopic) surgery.
Meniscal repair surgery
This involves suturing the torn portion of the tear in order to stabilise it. Different devices may be used depending on the tear pattern. Usually, the whole operation can be performed arthroscopically.
If the tear is highly unstable, Mr Pai may need to make an open incision over the side of the meniscal tear in order to perform “inside-out suturing” of the meniscus. This is considered amongst knee surgeons to be the gold standard of repair, as it has a slightly lower re-tear rate of the meniscus.
Repairing the meniscus is preferable to resecting it because it preserves more of the shock-absorbing function of the meniscus and will delay the onset of osteoarthritis. Every effort will be made when appropriate to repair the meniscus.
Meniscal root repair
This is a special variant of meniscal tear that occurs when the attachment of the meniscus to the front or back of the tibia is torn. This will completely impede the shock-absorbing capacity of the meniscus. Although the preference is always to repair this pattern of tear, the underlying quality of the tissue may preclude this.
Repairing a root tear involves passing stitches through the root attachment, which then get passed down a bony tunnel in the tibia and tied over a metal button or through a suture anchor embedded within the bone.
A successful repair of the meniscal root will allow the function of the meniscus to be retained and delay the onset of arthritis.
Meniscal resection
Sometimes the configuration or location of the meniscal tear precludes repair. If this is the case, then trimming the torn portion of the meniscus is performed to alleviate the symptoms.