Table of Contents
- Introduction to Meniscal Injuries
- A Patient’s Guide to Meniscal Injuries
Introduction to Meniscal Injuries
Five years ago, Dr. Goldblatt, orthopedic surgeon and professor at the University of Rochester School of Medicine (New York) wrote an article on meniscal (knee) injuries. It was published in the Journal of Musculoskeletal Medicine. Today, Dr. Goldblatt and two other orthopedic surgeons update that information here. More and more efforts are being made to save the damaged cartilage, first through conservative (nonoperative care) and when necessary, using surgery to repair the torn tissue whenever possible.
There are multiple levels of protective cartilage and soft tissues in and around the knee. The meniscus is one of them. Shaped like a crescent or horseshoe-shape, there are two of these thick, stiff pieces of cartilage in each knee. They are designed to help separate the joint, assist with smooth motion, transfer load, and generally, protect the joint. Modern treatment no longer just removes a torn or damaged meniscus. Long-term studies have shown over and over that this type of aggressive treatment puts the joint at risk for faster and worse wear and tear often leading to knee arthritis.
Arthroscopic surgery has made it possible to correct the problem by repairing the meniscus with a minimally invasive procedure. The updated technology has been aided by new treatment techniques such as meniscal regeneration and meniscal transplantation. Although most patients are candidates for meniscal repair, two groups must be considered separately: those who need or want a more conservative approach without surgery and those who qualify for meniscal regeneration and transplantation. Let’s take a look at the way treatment is chosen for each patient.
In the case of nonoperative care, the surgeon considers the age and activity level of the patient. Older adults who aren’t very active may do just fine with a rehab program of modified activity and strengthening exercises. The surgeon looks at how long the patient has had this problem (acute versus chronic). The chances of healing in a long-term injury (one that occurred months to years ago) are less than in a more recent injury.
What’s the condition of the joint? How bad is the tear? Could it heal on its own? Small tears along the edges of the cartilage have a better chance of healing because there is a better blood supply there. An MRI will help show how much blood supply there is and give the surgeon an additional tool when predicting who might get better with nonoperative versus surgical care. Tears on the inner aspect of the meniscus (especially large tears in multiple directions) don’t heal well and often need a little surgical help.
Sometimes patients are advised to try a conservative (rehab) program first. If symptoms are resolved and activities can be resumed, then great — surgery won’t be needed. But if after a trial of rehab lasting up to three months, there’s no improvement or pain persists with activities, then it’s time to think about surgery. The most successful operations are performed within the first 10 to 12 weeks after the injury first occurs.
When it comes to surgery, the goal is to save the meniscus but also stabilize the knee. It may be possible to repair the tear and/or reattach the torn edges. The surgeon shaves down any ragged edges in a procedure called debridement. Debridement may be all that’s needed to stimulate a healing response. In some cases, the surgeon may opt to suture loose edges back in place or even remove part of the damaged meniscus.
By taking a look at the cartilage using an arthroscope, it’s possible to see what condition the meniscus is in and how much degeneration has occurred. Too much degeneration and the meniscus won’t heal itself and can’t be saved. Likewise, if the tear is too long, too deep, or too displaced, then it might be necessary to actually remove part (or all) of the cartilage. This procedure is called a meniscectomy. No matter what, the surgeon always tries to preserve tissue and knee function.
The most difficult injuries to deal with are large tears in more than one direction (vertical and horizontal) and bucket handle tears. With a bucket handle tear, half the meniscus has pulled up away from the rest — like a bucket handle lifting up away from the bucket. One end of the meniscus can get folded back on itself.
For severely damaged menisci, meniscus repair implants may be possible. This procedure is fairly new and was first used about 10 to 15 years ago. Since then, two procedures have gained in popularity: meniscal allograft transplant and collagen meniscal implants. An allograft transplant uses meniscus donated by others (like an organ donor). Collagen implants use collagen (the basic building block of soft tissues) from animal (cow) tendons. The collagen provides a scaffold that fills in with meniscus-like tissue and fibrous cartilage cells. Collagen implants have two important advantages over allografts: they are widely available and don’t require a tissue match.
When considering which treatment approach to take, it’s important to consider the success rates (outcomes) for each procedure. That’s where researchers are working now to match the right patient with the procedure that will yield the best results. Over time with improved techniques, better patient selection, and matching each patient to the most appropriate procedure, success rates have improved dramatically.
For example, meniscal repair in young patients with a stable knee and tear in the outer portion of the meniscus is 80 to 95 per cent successful. Athletes in this group are able to get back into full sports action at a level equal to before the injury. Partial meniscectomy in someone who has good articular cartilage underneath has a 90 per cent chance of successful healing. This same procedure is only successful 60 per cent of the time when there’s damage underneath the torn meniscus or when the knee is unstable or misaligned.
Removing any portion of the meniscus will eventually result in degenerative changes in the joint. This may not happen for five to 10 years, and it is somewhat dependent on how active the patient is — more activity puts added stress on the joint and increases the risk. Hopes are pinned on meniscal transplants and implants for future successful results. It’s always better if the patient can form his or her own, durable, stable meniscus. Meniscal substitutes of this type aren’t perfect yet. Future efforts will be directed at finding alternatives that will result in normal, healthy meniscal tissue that will hold up over time under joint contact and force.
John P. Goldblatt, MD, et al. Managing Meniscal Injuries: The Treatment. In The Journal of Musculoskeletal Medicine. December 2009. Vol. 26. No. 12. Pp. 471-477.
A Patient’s Guide to Meniscal Injuries
The meniscus is a commonly injured structure in the knee. The injury can occur in any age group. In younger people, the meniscus is fairly tough and rubbery, and tears usually occur as a result of a forceful twisting injury. The meniscus grows weaker with age, and meniscal tears can occur in aging adults as the result of fairly minor injuries, even from the up-and-down motion of squatting.
This guide will help you understand
- where the meniscus is located in the knee
- how an injured meniscus causes problems
- what can be done for an injured meniscus
What is a meniscus, and what does it do?
There are two menisci between the shinbone (tibia) and thighbone (femur) in the knee joint. (Menisci is plural for meniscus.)
The C-shaped medial meniscus is on the inside part of the knee, closest to your other knee. (Medial means closer to the middle of the body.) The U-shaped lateral meniscus is on the outer half of the knee joint. (Lateral means further out from the center of the body.)
These two menisci act like shock absorbers in the knee. Forming a gasket between the shinbone and the thighbone, they help spread out the forces that are transmitted across the joint. Walking puts up to two times your body weight on the joint. Running puts about eight times your body weight on the knee. As the knee bends, the back part of the menisci takes most of the pressure.
Articular cartilage is a smooth, slippery material that covers the ends of the bones that make up the knee joint. The articular cartilage allows the surfaces to slide against one another without damage to either surface.
By spreading out the forces on the knee joint, the menisci protect the articular cartilage from getting too much pressure on one small area on the surface of the joint. Without the menisci, the forces on the knee joint are concentrated onto a small area, leading to damage and degeneration of the articular cartilage, a condition called osteoarthritis.
The menisci add stability to the knee joint. They convert the surface of the shinbone into a shallow socket, which is more stable than its otherwise flat surface. Without the menisci, the round femur would slide on top of the flat surface of the tibia.
How do meniscal problems develop?
Meniscal injuries can occur at any age, but the causes are somewhat different for each age group. In younger people, the meniscus is a fairly tough and rubbery structure. Tears in the meniscus in patients under 30 years old usually occur as a result of a fairly forceful twisting injury. In the younger age group, meniscal tears are more likely to be caused by a sport activity. The entire inner rim of the medial meniscus can be torn in what is called a bucket handle tear. The meniscus can also have a flap torn from the inner rim.
The tissue that forms the menisci weakens with age, making the menisci prone to degeneration and tearing. People of older ages often end up with a tear as result of a minor injury, such as from the up-and-down motion of squatting. Most often, there isn’t one specific injury to the knee that leads to the degenerative type of meniscal tear. These tears of the menisci are commonly seen as a part of the overall condition of osteoarthritis of the knee in aging adults. Degenerative tears cause the menisci to fray and become torn in many directions.
What does a torn meniscus feel like?
The most common problem caused by a torn meniscus is pain. The pain may be felt along the edge of the knee joint closest to where the meniscus is located. Or the pain may be more vague and involve the whole knee.
The knee may swell, causing it to feel stiff and tight. This is usually because fluid accumulates inside the knee joint. This is sometimes called water on the knee. This is not unique to meniscal tears, since it can also occur when the knee becomes inflamed.
The knee joint can also lock up if the tear is large enough. Locking refers to the inability to completely straighten out the knee. This can happen when a fragment of the meniscus tears free and gets caught in the hinge mechanism of the knee, like a pencil stuck in the hinge of a door.
A torn meniscus can cause long-term problems. The constant rubbing of the torn meniscus on the articular cartilage may cause the joint surface to become worn, leading to knee osteoarthritis.
How do doctors identify this problem?
Diagnosis begins with a history and physical exam. Your doctor will try to determine where the pain is located, whether you’ve had any locking, and if you have any clicks or pops with knee movement. X-rays will not show the torn meniscus. X-rays are mainly useful to determine if other injuries are present.
Magnetic resonance imaging (MRI) is very good at showing the meniscus. The MRI machine uses magnetic waves rather than X-rays to show the soft tissues of the body. This machine creates pictures that look like slices of the area. Usually, this test is done to look for injuries, such as tears in the menisci or ligaments of the knee. This test does not require any needles or special dye and is painless.
If there is uncertainty in the diagnosis following the history and physical examination, or if other injuries in addition to the meniscal tear are suspected, the MRI scan may be suggested.
If the history and physical examination indicate a torn meniscus, arthroscopy may be suggested to confirm the diagnosis and treat the problem at the same time. Arthroscopy is an operation that involves inserting a miniature fiber-optic TV camera into the knee joint, allowing the orthopedic surgeon to look at the structures inside the joint directly. The arthroscope lets the surgeon see the condition of the articular cartilage, the ligaments, and the menisci.
Treatment for Meniscus Injuries
What can be done for this injury?
Initial treatment for a torn meniscus focuses on decreasing pain and swelling in the knee. Rest and anti-inflammatory medications, such as aspirin, can help decrease these symptoms. You may need to use crutches until you can walk without a limp.
Some patients may receive physical therapy treatments for meniscal problems. Therapists treat swelling and pain with the use of ice, electrical stimulation, and rest periods with your leg supported in elevation. Exercises are used to help you regain normal movement of joints and muscles.
If the knee keeps locking up and can’t be straightened out, surgery may be recommended as soon as reasonably possible to remove the torn part that is getting caught in the knee joint. But even a less severely torn meniscus may not heal on its own. If symptoms continue after nonsurgical treatment, surgery will probably be suggested to either remove or repair the torn portion of the meniscus.
Surgeons use an arthroscope (mentioned earlier) during surgery for an injured meniscus. Small incisions are made in the knee to allow the insertion of the camera into the joint.
The procedure to take out the damaged portion of the meniscus is called a partial meniscectomy. The surgeon makes another small incision. This opening is needed to insert surgical instruments into the knee joint. The instruments are used to remove the torn portion of the meniscus, while the arthroscope is used to see what is happening.
Surgeons would rather not take out the entire meniscus. This is because the meniscus helps absorb shock and adds stability to the knee. Removal of the meniscus increases the risk of future knee arthritis. Only if the entire meniscus is damaged beyond repair is the entire meniscus removed.
Whenever possible, surgeons prefer to repair a torn meniscus, rather than remove even a small piece. Young people who have recently torn their meniscus are generally good candidates for repair. Older patients with degenerative tears are not.
To repair the torn meniscus, the surgeon inserts the arthroscope and views the torn meniscus. Some surgeons use sutures to sew the torn edges of the meniscus together. Others use special fasteners, called suture anchors, to anchor the torn edges together.
Surgeons are beginning to experiment with different ways to replace a damaged meniscus. One way is by transplanting tissue, called an allograft, from another person’s body. Further investigation is needed to see how well these patients do over a longer period of time.
What should I expect from treatment?
Nonsurgical rehabilitation for a meniscal injury typically lasts six to eight weeks. Therapists use methods such as electrical stimulation and ice to reduce pain and swelling. Exercises to improve knee range of motion and strength are added gradually. If your doctor prescribes a brace, your therapist will work with you to obtain and use the brace.
You can return to your sporting activities when your quadriceps and hamstring muscles are back to nearly their full strength and control, you are not having swelling that comes and goes, and you aren’t having problems with the knee giving way.
Rehabilitation proceeds cautiously after surgery on the meniscus, and treatments will vary depending on whether you had part of the meniscus taken out or your surgeon repaired or replaced the meniscus.
Patients are strongly advised to follow the recommendations about how much weight can be borne while standing or walking. After a partial meniscectomy, your surgeon may instruct you to place a comfortable amount of weight on your operated leg using a walking aid. After a meniscal repair, however, patients may be instructed to keep their knee straight in a locked knee brace and to put only minimal or no weight on their foot when standing or walking for up to six weeks.
Patients usually need only a few therapy visits after meniscectomy. Additional treatments may be scheduled if there are problems with swelling, pain, or weakness. Rehabilitation is slower after a meniscal repair or allograft procedure. At first, expect to see the physical therapist two to three times a week. If your surgery and rehabilitation go as planned, you may only need to do a home program and see your therapist every few weeks over a six-to eight-week period.
Meniscus Injuries FAQ
- Swelling and stiffness.
- Your knee catching or locking.
- The feeling that your knee is giving out.
- You are unable to extend or flex your knee fully.
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