Meniscus and Articular Cartilage Injuries How are they Treated?

 

Meniscus and Articular Cartilage Injuries How are they Treated?

Meniscus and Articular Cartilage Injury Treatment Options

Steve A. Mora, MD

Board Certified Orthopedic Surgeon Specializing in Knee Injuries, Orange County, Ca

You have injured your knee. Now what do you do?

Knee injuries are a very common problem especially in individuals who are active with running and pivoting type sports. Knee cartilage or meniscal injuries are also common in workers and as a consequence to repetitive loading and twisting.  Believe it or not a meniscus tear can also happen in folks from simply squatting or coming up from a bent position.  Therefore knee cartilage or meniscus injuries can occur in the most active to the less active sedentary type.

Knee meniscus and articular cartilage / chondral tears are among the most common injuries I see in my Orange County Orthopedic surgery practice.  This is probably because the knee joint is subject to heavy joint loading forces because of constant pounding associated with every day activities.  Did you know that running increases the force across the knee upwards to 5x your body weight?  Often times meniscus or articular cartilage tears occur in conjunction with other injuries especially anterior cruciate ligament (ACL) tears and medial collateral ligament tears (MCL).

In younger athletes, whose cartilage is at its peak of resiliency, meniscus tears require more force to occur and are more likely to be of the bucket-handle variety or clean cut type.  These tears might require suture repair. In older athletes, whose meniscus cartilage becomes increasingly brittle , complex tears with multiple fragments or pieces are more common.  These tears usually require trimming.

Articular cartilage tears, aka chondral defects are injuries to the joint surface or lining.  These lesions occur in similar fashion as a meniscus tear.  The younger the patient the more likely the lesion is isolated and discrete.  The older the patient, the more likely the lesion is degenerative and diffuse (degenerative joint disease).  Some chondral lesions occur without a known reason such as a Osteochondritis dissecans (OCD).  Most of the time chondral lesions are associated with ACL tears.  Actually, most of the time a chondral lesion is identified at the time of meniscus tear surgery.  In these situations the surgeon has to have a game plan for treatment of the surprise tears.  Not all chondral lesions are symptomatic, that is, not all of them cause pain.  For this reason it is critical for the surgeon to understand the location of your pain.  For example if you have medial pain from a medial meniscus tear but a lateral chondral defect is noted at time of surgery.  It is quite possible the surgeon may elect to leave the lesion alone.

KNEE ANATOMY & FUNCTION

The knee joint is designed to allow synchronous motion and force distribution. To achieve this, the joint design is a complex relationship between bone, ligament, articular cartilage, and meniscus.

The femur is the upper portion of the knee joint. It is covered with articular cartilage or chondral surface/lining.  The articular cartilage allow for motion to occur with very low friction. The articular surface has a thickness of about 6-6 mm.  When it is damaged, the severity of damage is graded based on the depth of the damage.  For example a surface injury involving less than half the thickness is graded I or II.  If the damage extends more than half of the thickness it is graded III or IV (injury is down to bone).

The femur above matches up with the flat shaped tibia below. The tibia is also covered with a layer of articular cartilage.  The flat surface of the tibia has two semilunar fibrocartilages, medial and lateral meniscus, that are attached to its medial and lateral surface. The medial and lateral menisci act as shock absorbers or cushions for the joint.  The medial meniscus is often times torn.  The menisci are firm structures, a bit like thick rubber washers.  Their blood supply is not so great therefore if they tear they don’t usually heal.  The ACL, MCL, LCL and PCL are the large ligaments that keep the femur and tibia bones aligned properly.  On the front of the knee joint lies the patella bone.  It is the third bone that makes up the knee joint.  Its undersurface is also covered with a thick layer of articular cartilage.  The patella bone is important for bending, squatting and stair climbing.  People who do a lot of kneeling or climbing often feel anterior knee pain secondary to the cartilage wearing down.  This is called chondromalacia patella.

Patients who have arthritis will have damage to both the meniscus and the chondral surface.  The wear and tear pattern is diffuse and involves most of the surface.  Arthritis is a pathology that has  a spectrum, that is, it probably started with an isolated meniscus or chondral lesion, which led to a situation of progressive breakdown of the joint causing worsening cartilage/chondral damage which eventually lead to complete wear down of the joint.  In some patients the arthritis is localized initially to only one third of the joint (medial vs lateral vs patellofemoral joint).  These patients might be candidates for partial knee replacements.

Review-What kind of cartilage does the knee joint contain?

1. Meniscus Cartilage, or just called meniscus.  When damaged it’s called a meniscus tear.  Medial and Lateral.  They act as 2 cushions between the femur and tibia and they work like a shock absorber.  They have a poor blood supply so they rarely heal.  Tears can be identified readily well with an MRI.

2. Articular or Hyaline Cartilage.  When damaged it can be referred to as:  chondral defect or chondral injury or articular cartilage injury, or osteochondral injury.  It is slick, firm, durable and it effectively covers the ends of the femur, patella and tibia.  It allows for near friction-less movement.  As of date, we cannot re-create natural cartilage.  Doctors or scientist cannot re-coat a worn down knee.  We can harvest and grow cartilage cells but unfortunately we cannot make the actual cartilage.  The nearest substitute we have is a metal/plastic/ceramic joint replacement which is far from natural.  Chondral defects are difficult to see on MRI.

When the articular cartilage and the meniscus are damaged severely, over the course of many years, and, when the space between the femur tibia or patella decreases (joint space narrowing), it is called arthritis.

Does a Meniscus tear hurt differently than a Chondral lesion? What are the symptoms?

The patient with torn meniscus or chondral injury will feel very similar symptoms.

-localized pain along the line of the knee joint
-swelling with activity
-stiffness and feeling of pressure especially posteriorly and above the patella
-catching or clicking.  Usually more apparent with meniscus tears.
-a cyst in the back of the knee is usually associated with a meniscus tear
-a locked knee is usually associated with a specific type of meniscus tear called a bucket handle tear
-a chondral injury under the patella usually causes anterior knee pain with bending
-chondral lesions tend to cause pain and stiffness especially when trying to walk after sitting for a long time.  I call this the movie theater sign (very painful knee after watching a movie).

Both types of cartilage tears can lead to a decrease in performance. The bigger the meniscus tear or chondral defect, the more severe the symptoms.

As you can see the symptoms between these 2 different pathologies is very similar.  It is very difficult for your surgeon to say with 100% you have one or the other based on exam alone.  Sometimes you can actually have both types of tears at the same time.

How is the injury diagnosed?

-Good History (talking AND listening to the patient)
-Good Examination (touching the knee)
-Xray: Yes, even in this day and age where everyone gets an MRI, the xray tells us valuable information.  Please do not get mad at your doctor for ordering xrays and a MRI. Standing xrays actually tell us a lot about the presence or absence of arthritis.
-MRI:  Good for meniscus tears.  Average for small or partial thickness chondral lesions.

How is a cartilage tear or meniscus tear initially treated?

The Initial treatment for meniscal or cartilage injuries:

-Rest
-Ice
-Compression with an ACE wrap
-Elevation to decrease swelling of the knee as well as the ankle
-Medications: over the counter Advil or Aleve

Red Flags See your doctor as soon as possible if:
-Your knee is stuck in a bent position. You probably have a bucket handle tear.
-If at the time of injury you felt a “pop”. Could be a ACL tear or patella tendon rupture.
-patella dislocated

Treatment Options

The Conservative Approach (No surgery) or Optimistic Observation

The conservative option is best for those individuals who have little pain and who are still able to perform at a acceptable level  If you can do what you need to do in life you don’t need to have surgery. Also in cases where the pain is significant but your surgeon thinks there is a chance the tear heals you should start here.  Non operative treatment can include a steroid injection, PT, weight loss, medication, OrthoVisc (Hyaluronate) injection, bracing and activity modification.

Knee Arthroscopy and Meniscus and Articular Cartilage Care

This option should be selected for healthy individuals who have a documented (MRI) meniscus tear or an articular cartilage defect and who have persistent symptoms recalcitrant to non operative treatment measure..

Meniscus tears usually get treated by trimming the loose torn pieces.  This procedure is called partial meniscectomy.  Arthroscopy is done under general anesthesia although I can do it with local and IV sedation in patients who cannot tolerate general anesthesia.  Spinal anesthesia is not recommended for arthroscopy.  Two small incisions are made to introduce the arthroscope and a slender trimming instrument.  I tell patients it is similar to trimming a hang nail.  The trimming tool is like a nail clipper.  It is used to clip or trip loose pieces and then smooth out remaining meniscus tissue.  The procedure is Out-patient.  You go home the same day and usually use a cane for a week.  You will see me for a Post-Op check one week later.  After the Post-Op check physical therapy is started and done 2x per week for 6 weeks.  Patients usually go back to sports at 6 weeks.  We can also repair the torn meniscus in highly selective cases where the tear looks like a clean cut.  Repair is usually possible in teenagers or younger patients.  When a repair is done the patient has to use crutches and a brace for 6 wks.  No running sports for 6 months.

Chondral, aka, Articular Cartilage Defects:  Are initially treated using arthroscopic methods, done as outpatient, and require general anesthesia.  Remember that oftentimes these lesions are not discovered until the time of the surgery for a meniscus tear.  It would not be right to ignore these lesions if there is a possibility they are generating some or all the pain.  The treatment option depends on the depth and diameter of the lesion.

For all Partial thickness Chondral lesions (grade III and below): Treated with debridement or simple chondroplasty.  This means the rough surfaces and edges are shaved and smoothed out.

For Full thickness Chondral lesions, those lesions which have eroded completely down to bone (grade IV) other options can be considered.  These options are available for chondral lesion which have failed simple chondroplasty or debridement.

Microfracture Chondroplasty- This is usually the first line of cartilage repair for Grade IV defects or for those which have already undergone simple debridement as mentioned above.  A small pick-type tool (awl) is used to make perforations or pick holes in the bone within the center of the lesion. These holes allow blood from the marrow to come in and fill the defect.  With time the marrow blood will firm up and become a type of repair cartilage which will cover the bone.  In approximately 80% of these cartilage defects there is a good degree of repair cartilage formation which should lead to less pain.  The major downside:  crutches and motion machine (CPM) for 6 weeks as the repair cartilage forms.  No running for 6 months.  Possibility of incomplete pain relief (failed repair).

If we find a full thickness defect that is very large or one that has not healed with Microfracture,  secondary methods of repair can be done at a later date.  These include:

Osteochondral grafting (OATS) I take small plugs of bone and cartilage from a less critical area of the knee and transfers them to the injury site.  Its like a hair plug for men procedure in the knee.  Sometimes it requires a 2-3 inch incision.  Also requires 6 wks crutches, CPM and no running sports for 6 months.  The plugs can also be taken from a cadaver knee.  This graft would be called Fresh Allograft Osteochondral transfer.

Autologous Chondrocyte Implantation (ACI) a.k.a. Genzyme:  Cartilage cell transfer procedure.   A relatively new technique of repair that takes a biopsy (small specimen) of your articular cartilage at the time of your initial knee arthroscopy.  It is sent to a lab and “cloned” to create millions of chondrocytes (the cells that make articular cartilage).  Once the right number of cells are grown (12 million), the cells are transferred into the full thickness chondral defect by through a 4-5 inch incision. Essentially you have to have 2 surgeries, one to harvest the sample and the other to implant the cells.  Only physicians trained and certified in this technique are able to provide this option.  This technique has been used to resurface large defects, greater than 2cm diameter, and has been proven to work well for very specific cases.  Not everyone is a candidate for this surgery.  The defect has to be isolated and not the arthritic type.  Chondral lesions of the patella and trochlea do not do as well. This is a big surgery with potential side effects or complications.  The chance of having going back to professional sports is no excellent.  It requires 12 weeks of crutches and no sports for 12 months.  It is a good option for a young patient with major symptoms stemming from an isolated chondral defect which has not responded to microfracture.

If you do some web research you will find a plethora of information regarding chondral lesion treatment.  These are usually very complex or semi experimental.  For example a Tibial tubercle osteotomy is an option for severe patella chondral lesions.  I have done these in highly specif situations with good results.  There is also allograft meniscus transplant for young patients whom have had massive meniscus tears already treated with meniscectomy and who have late onset pain. I also perform these in the rare young patient with total loss of meniscus.  There is Partial knee replacement for single compartment degenerative chondral defects.  I do these in our older population.  Fresh allograft transplantation are procedures I do for chondral defects with deep bone loss.  These procedures are very good for OCD or massive traumatic osteochondral defects.  This is a highly complex procedure but still a good option in special cases.

Procedure I do NOT do:  There are also metallic caps that are being inserted into the knee to provide a metal surface.  These metal implants do not have a strong track record and are questionable in regards to success.   There is a company trying to introduce a synthetic meniscus.  There is a company offering morselized baby cartilage which can be made into a putty and pressed into the defect (Denovo).  There is no proof at all that this is an effective treatment.  There are also studies underway using morselized articular autograft (CAIS).

We will see what the next few years bring to fruition.

What is best for you? Everyone is different.

• There is no rush to do surgery (unless you have a displaced bucket handle tear or your knee is locked.
• Secondly, you must define your athletic/work goals in regards to the season and schedule.  Some athletes will wait until the season is over to seek treatment as long as they can still play to an acceptable degree. Others want surgery ASAP because they want to be ready for the next season.  Same applies to people who have jobs.  Some patients will wait for the slower months or the holidays to do surgery.
• Before deciding on “what is best for you” you have to look at the risks and benefits of all treatment above, both operative and non-operative.  Typical questions you should ask are:

“What are the chances I heal well WITHOUT surgery?”  If you have had the tear for more than 6 months it is probably not going to heal.  Also if you have had the tear for more than 3 months and you have already had treatment with PT and injection, it is probably not going to heal.  If you have a displaced bucket handle tear it is not going to heal period.

“What are the chances I heal well WITH surgery? “It depends on the exact pathology.  Usually simple meniscus tear trimming of small to medium size tears heal very well.  If you have meniscus repair or microfracture of a chondral lesion there is a small chance it does not heal so you will need another surgery in about 6-9 months.

“How much time should I give my knee to heal without surgery before choosing to operate”.
Depends on the trend.  Are you getting better and better each month?  If yes keep waiting.  Are you getting worse? Operate if non op measure have been done.  Do you need to be ready for next season? If yes, don’t wait so long to decide.  Do you have a vacation from work coming up in a couple of weeks?  If yes ask your surgeon if its too soon or if it’s reasonable to do surgery.

Am I making it worse by being active or playing sports?  If you are not experiencing significant swelling or pain you are probably not making it worse.  However I cannot say this with 100% certainty.  The more pain there is the more likely the loose pieces are catching or rubbing on other surfaces.  In rare cases a meniscus tear can become displaced with strenuous activity.  If you are experiencing catching, giving way, or moderate/sever swelling, shut it down.

“If I have surgery what is the likelihood I will have an excellent result?”  Many patients will ask “will I be 100% or back to normal after the surgery”  I will tell you now that you probably will not be 100% or totally normal.  However after most simple knee arthroscopy surgeries for meniscus tears, most patients (85%-95%) will have a excellent result that allows them to function at their desired level with minimal to no complaints.  The patients whom I find experience difficulty with recovery are those with a meniscus tear and arthritis.  After the meniscus tear is fixed the arthritis continues to be a problem even in those patients who were “fine before the tear”.

Is the possibility of a complication high? Or is it very unlikely/rare?
Most surgeries for meniscus or chondral lesions are not risky.  Nonetheless if you do suffer a rare complication, it may lead to further surgery or delayed recovery. 

Am I better off coping with the pain, ie living with the pain, changing my sport, and not have surgery?  This is a personal decision you will ultimately have to make on your own.  However the information your surgeon gives you will help you make the right decision for you.  For example, if a chondral defect has undergone one surgery but requires a more surgery, the surgeon might tell you the chance of an great result is low.  In this situation you should ask yourself if you are willing to go through another surgery, do rehabilitation/PT (again), take time off work (again), deal with crutches, and struggle with the emotional stress all over again. Some patients will say it is not worth it especially if they can do most activities.

Even if I have surgery, is it likely that I will be able to play my game or go back to work at pre-injury level?  The goal for most surgeons is to get you back to the level of function which you desire. That function could be related to athletic or work activities.  Some chondral injuries or meniscus tears are so severe that even with the best surgery the final level of performance is still not great.  For the most part many patients are able to return to high level sports especially with a small to medium size meniscus tear. Chondral lesions are a differently animal and not as predictable.  The general rule for chondral injuries is that the smaller the defect the more likely things will turn out well.

If there are any questions at any time… Please ask!!!!  Remember that the purpose of this document is to educate and help you understand the complexities your knee injury and its treatment.

Please do not hesitate to call our office if you have any further questions
714 639-3750

Thank you for your time.

Steve A. Mora, MD
Board Certified Orthopedic Surgeon Specializing in Knee Surgery, Orange, Ca

Please contact me with questions at http://myorthodoc.com/physicians/stevemoramd.html

Dr. Mora is a Board Certified Orthopedic Surgeon practicing in OC Orange County.  He can be reached through his webpage above.  Call 714 639-3750 for a comprehensive consultation.