Arthroscopy of the Knee Joint
The arthroscope is a fiber-optic telescope that can be inserted into a joint (commonly the knee, shoulder and ankle) to evaluate and treat a number of conditions. A camera is attached to the arthroscope and the picture is visualized on a TV monitor. Most arthroscopic surgery is performed on an outpatient basis and is usually done under general anesthesia. Knee arthroscopy is common, and millions of procedures are performed each year around the world.
Arthroscopy is useful in evaluating and treating the following conditions:
- Torn floating cartilage (meniscus): The cartilage is trimmed to a stable rim or occasionally repaired
- Torn surface (articular) cartilage
- Removal of loose bodies (cartilage or bone that has broken off) and cysts
- Reconstruction of the Anterior Cruciate ligament
- Patello-femoral (knee-cap) disorders
- Washout of infected knees
- General diagnostic purposes
Basic Knee Anatomy
The knee is the largest joint in the body. The knee joint is made up of the femur (thigh bone), tibia (leg bone) and patella (knee cap). All these bones are lined with articular (surface) cartilage. This articular cartilage acts like a shock absorber and allows a smooth low friction surface for the knee to move on. Between the tibia and femur lie two floating cartilages called menisci. The medial (inner) meniscus and the lateral (outer) meniscus rest on the tibial surface cartilage and are mobile. The menisci also act as shock absorbers and stabilizers. The knee is stabilized by ligaments that are both in and outside the joint. The medial and lateral collateral ligaments support the knee from excessive side-to-side movement. The (internal) anterior and posterior cruciate ligaments support the knee from buckling and giving way. The knee joint is surrounded by a capsule (envelope) that produces a small amount of synovial (lubrication) fluid to help with smooth motion. Thigh muscles are important secondary knee stabilizers of the knee.
Routine X-Rays of the knee, which include a standing weight-bearing view are usually required. An MRI scan which looks at the cartilages and soft tissues may be needed if the diagnosis is unclear. Occasionally, a CT Scan may also be helpful. There is little value in the use of Ultrasound in investigating knee problems.
Meniscal Cartilage Tears:
Following a twisting type of injury a medial or lateral meniscus can tear. This results either from a sporting injury or may occur from a simple twisting injury when getting out of a chair or standing from a squatting position. Our cartilages become a little brittle as we get older and therefore can tear a little easier. The symptoms of a torn cartilage include
- Pain over the torn area i.e. inner or outer side of the knee
- Knee swelling
- Reduced motion
- Locking if the cartilage gets caught between the femur a tibia
- Giving way or a sense of instability
Once a meniscal cartilage has torn it will not heal unless it is a very small tear or that is near the outside edge of the joint where blood vessels are located. Since joint cartilages and meniscus cartilage have no blood supply in them, they have no ability to heal. Once the cartilage has torn it predisposes the knee to develop osteoarthritis (wear and tear) in subsequent years. Removal of torn pieces from the knee is indicated if the knee is symptomatic with pain, locking, popping, or giving way.
Torn cartilages in general continue to cause symptoms of discomfort, pain and swelling until the loose, ragged pieces are removed. Only the torn section is removed and the knee should improve after several weeks if no other significant abnormalities are identified in the knee joint during arthroscopy. If the entire meniscus is removed, the knee has a likelihood of developing osteoarthritis in subsequent months or years. It is standard to remove only the torn section of cartilage in the hope that this will delay the onset of long-term wear and tear osteoarthritis.
Occasionally, provided the knee is stable and the tear is a certain type of tear in a young patient (peripheral bucket handle tear), the meniscus may be suitable for repair. If repaired, one has to avoid weight bearing on the involved leg for several weeks and avoid sports for a minimum of three months.
Articular Cartilage (Surface) Injury:
If the surface cartilage is torn or damaged, significant shock-absorbing function of the joint is compromised. Large pieces of articular cartilage can float in the knee (sometimes with bone attached) and this causes locking of the joint and can cause further deterioration due to the loose bodies floating around the knee causing further wear and tear. Most surface cartilage wear will ultimately lead to osteoarthritis. Mechanical symptoms of pain, swelling, locking, popping and giving way due to cartilage peeling off can be helped with arthroscopic surgery. The surgery smoothes the edges of the surface cartilage and removes loose bodies.
Anterior Cruciate Ligament Injuries:
Rupture of the Anterior (rarely the posterior) Cruciate Ligament (ACL) is a common sporting injury. Once ruptured the ACL does not heal and usually causes knee instability and the inability to return to normal sporting activities. An ACL reconstruction is required and a new ligament is fashioned to replace the ruptured ligament. This procedure is performed using the arthroscope. After this type of surgery extensive Physical Therapy is usually necessary and avoidance of sports is also possible for up to a year. This injury is frequently associated with other injuries inside the knee joint such as meniscus cartilage tears, joint surface cartilage tears or injuries and bone bruises that can ultimately lead to the development of arthritis.
Patella (knee-cap) Disorders:
The arthroscope can be used to treat problems relating to kneecap disorders, particularly mal-tracking and significant surface cartilage tears. The majority of common kneecap problems can be treated with physical therapy and rehabilitation. Occasionally, surgery is indicated if the patient has not improved with conservative and non-operative methods.
therapy and rehabilitation.
Arthroscopy is used in inflammatory conditions (e.g. Rheumatoid Arthritis) to help reduce the amount of inflamed synovium (joint lining) that is producing excess joint fluid that causes the knee to swell and be painful. This procedure is called a synovectomy. Arthroscopic surgery for rheumatoid arthritis sometimes may also decrease the worsening of the arthritis in the knee.
Bakers cysts or popliteal cysts are often found on clinical examination and ultrasound / MRI scan. The cyst is a fluid filled cavity behind the knee and in adults arises from a torn meniscus or worn articular cartilage in the knee. These cysts usually do not require removal as treating the cause (torn knee cartilage) will in most cases reduce the size of the cyst. Occasionally the cysts rupture and can cause calf pain. The cysts are not dangerous and do not require treatment if the knee is asymptomatic.
Isolated areas of articular cartilage loss can be repaired using cartilage transplant technology. This is a new and exciting field that is developing in the treatment of specific isolated cartilage defects in younger patients
The process is called Autologous Chondrocyte Grafting . It involves harvesting cartilage cells from the affected knee, sending these cells to a laboratory and then culturing the cells to multiply into many cells. The large amount of cells produced are then placed back into the affected knee into the defect requiring resurfacing. Results are still short-term follow-up but are looking encouraging.
After a major cartilage or ligament injury has been treated the knee can have improved function with the goal of returning to sports activity, work or exercise. There is however an increase in the risk of developing long-term wear and tear (Osteoarthritis) and depending on the degree of injury, activity modification may be required. Activities that help prevent knees deteriorating quickly include:
- Low impact sports like swimming, cycling and walking
- Reducing weight and maintaining a healthy diet
Arthroscopy of the Knee: Patient Information
Please stop taking Aspirin and Anti-inflammatory medications 7 days prior to your surgery. You can continue taking all your other routine medication. If you smoke you are advised to stop several days prior to your surgery. If you are coumadin, warfarin, plavix or other blood thinners, these medications also need to be discontinued several days prior to surgery but you need to contact your primary care physician and Dr. Fox to determine if it is safe to do so. Other blood thinners such as short-acting injectable medications may need to be used to decrease the risk heart attack, stroke or blood clots.
You will be admitted on the day of surgery and need to avoid eating or drinking for 12 hours prior to the procedure.
The limb undergoing the procedure will be marked and identified prior to the anesthetic being administered.
Once you are under anesthetic, the knee is prepared in a sterile fashion. A tourniquet is placed around the thigh to allow a 'blood - free' procedure.
The Arthroscope is introduced through a small (size of a pen) incision on the outer side of the knee. A second incision on the inner side of the knee is made to introduce the instruments that allow examination of the joint and treatment of the problem. The surgery may take as little as 20 minutes or several hours depending on the extent of the corrections necessary. Local anesthetic and other medications may be injected into your knee after the surgery to give you excellent pain relief. The effects of this medicine may last for several hours-even into the following day.
You will wake up in the recovery room.
A bandage will be around the operated knee.
Once you are recovered, your IV will be removed and you will be shown a number of exercises to do.
Your Surgeon will see you and a family member prior to discharge and explain the findings of the operation and what was done during surgery. However, due to the anesthetics utilized, the patient frequently does not remember that conversation and therefore it is important for the patient to bring someone as a "second set of ears."
After the surgery, but before you leave the operating room, local anesthetic and other medicines will be injected into your knee. This should give you very good relief of pain until the following day.
Crutches or a walker will be supplied to you in the recovery room. You should use them for the first 3-4 days after surgery unless otherwise instructed.
Pain medication will be provided and should be taken as directed once you feel the numbing medicines in the knee start to wear off. Even with extensive operations your pain level should be controlled with the pain methods provided and it would be expected that you can discontinue the narcotic pain medications within about a week or less. For those instances when pain continues, typically extra-strength Tylenol, Motrin, Advil, or Aleve should be adequate. Keeping swelling down by using ice and elevation of your leg above your heart will also decrease pain, stiffness and risk of blood clots.
You can remove the bandage in 2-3 days, wash the wounds with soap and water or peroxide and cover the wounds with Band-Aids or dry gauze and replace the ace wrap (provided) over the wounds. You should call the office or return quickly if you notice an increase in swelling, have increased pain in your groin, thigh, knee or calf, have redness or drainage of fluid from around the wounds, have shortness of breath or chest pain, fever or chills. These symptoms could represent evidence of infection or blood clots.
It is NORMAL for the knee to swell after the surgery. Elevating the leg when you are seated and placing ice packs on the knee will help to reduce swelling. (Ice packs on for 20 min 3-4 times a day until swelling has reduced). You could potentially have swelling for several days so continue ice an elevation as long as necessary. Try to keep your leg elevated above your heart as much as possible especially during the first several days. The easiest method is to lay on your couch with your leg over the back of the couch.
It is important to begin range of motion exercises as soon as possible unless otherwise instructed. These exercises should include bending and straightening your knee for a series of 10 repetitions, at least 3-4 times per day, for several days. A handout with pictures of the exercises has been given to you. You should even try starting and doing the exercises in the recovery room. Supervised physical therapy is usually not necessary after the typical arthroscopic procedure, but if upon your return to the office in about 10 days for your first post-operative appointment we find you are having trouble progressing with your therapy and activity level, physical therapy will be prescribed.
Blood clots are a concern after surgery so it is recommended that you do things to keep your swelling down, remain active without overdoing it and do frequent ankle pumps multiple times per day. If you are normally on a blood thinner you should start back on that medicine after surgery. If you are not on blood thinners you should take an adult size, 325mg aspirin, twice a day for 2 weeks.
You are able to drive and return to work when comfortable unless otherwise instructed but only if you are narcotic pain medications. If your right leg has been operated on, good muscular control of your leg is needed to safely drive. You should be able to walk comfortably, raise your leg easily and bend your knee more than 100 degrees before attempting to drive. If in doubt, practice in a large parking lot or at least your driveway-away from other traffic.
Please make an appointment 10 days after surgery to monitor your progress and remove the 2 stitches in your knee. The office number is 480-345-2031.
Risks of Anesthesia:
The arthroscopic surgeries are usually done under general anesthesia unless certain circumstances dictate against that. General Anesthetic risks are rare. The Anesthesiologist will discuss the risks of anesthesia more specifically. Occasionally patients have some discomfort in the throat as a result of the tube that supplies oxygen and other gasses during surgery. Please discuss with the Anesthesiologist if you have any specific concerns such as prior problems with anesthesia, allergies to medicines, medical problems such as heart or lung disease, bleeding problems or family history of anesthetic complications.
Risks related to Arthroscopic Knee Surgery Include:
- Postoperative bleeding
- Deep Vein Thrombosis (blood clots)
- Numbness to part of the skin near the incisions
- Injury to vessels, nerves and a chronic pain syndrome
- Progression of the disease process such as arthritis
The risks and complications of arthroscopic knee surgery are extremely small. One must however bear in mind that occasionally there is more damage in the knee than was initially thought and that this may affect the recovery time. In addition if the cartilage in the knee is partly worn out then arthroscopic surgery has about a 65% chance of improving symptoms in the short to medium term but more definitive surgery may be required in the future. In general, arthroscopic surgery does not improve knees that have well established Osteoarthritis. In some cases a knee replacement may be necessary to adequately relieve your pain. Sometimes the extent of the arthritis or other damage in the knee may not able to be fully evaluated with xrays, MRI scans and physical exam. The full extent of the abnormal findings can be more accurately visualized by the arthroscope. Pictures of the inside of your knee usually are taken and will be reviewed with you when you return to the office for the first post op visit.
You may have persistent pain, swelling and stiffness and may not be able to return to certain work, sport, or hobby activities.
Post -Operative Exercises and Physical Therapy
Following your surgery you will be given an instruction sheet showing exercises that are helpful in speeding up your recovery. Strengthening your thigh muscles (Quadriceps and Hamstrings) is most important. Swimming and cycling (stationary or road) are excellent ways to build these muscles up and improve movement.
Frequently asked questions:
How long am I in the Hospital?
A: Approximately 4 hours
Do I need crutches?
A: Usually for the first few days.
When can I get the knee wet?
A: A: After 48 to 72 hrs you may remove the bandage and shower if no wound drainage. If there is concern about the wound you wrap the knee with saran wrap. After showering cover the wounds with dry dressings or Band Aides and rewrap your leg with the ace wrap.
When can I drive?
A: After about 3-4days if the knee is comfortable, if you are not taking narcotics and you have good muscular control of your leg in the case of the right lower extremity with an automatic transmission. If you drive a vehicle with a manual transmission further delay in driving will be necessary.
When can I return to work?
A: When the knee feels reasonably comfortable but try to keep the leg elevated and apply ice as much as possible such as at break times, lunch etc.
When can I swim?
A: After several days (6-7) if no wound drainage or redness.
How long will my knee take to recover?
A: Depending on the findings and surgery, usually 4 to 6 weeks following the surgery unless more extensive surgery has been carried out. (see below)
When Can I return to Sports?
A: Depending on the findings, 4-6 weeks after surgery. If a ligament reconstruction, meniscus repair, microfracture technique or other certain procedures have been done, return to sports may be 6 months to a year.