Knee Joint Arthroscopy

By Kevin M. Kaplan, MD

Knee Joint Arthroscopy

By Dr. Kevin Kaplan

Knee joint arthroscopy is common, and there are millions of procedures each year around the world. 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 within the arthroscope and the picture is visualized on a TV monitor. Most arthroscopic surgery is a same day surgery and is usually done under general anesthesia.

Knee Joint Arthroscopy is Useful in Evaluating and Treating the Following Conditions:

• Torn floating cartilage (meniscus): The cartilage is trimmed to a stable rim or repair.
• Torn surface (articular) cartilage.
• Removal of loose bodies (cartilage or bone that has broken off) and cysts.
• Reconstruction of the Anterior Cruciate ligament.
• Patellofemoral (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 consist of the femur, tibia and patella (knee cap). All these bones have a lining of 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.

Ligaments of the knee provide stability 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 capsule surrounds the knee.  It produces a small amount of synovial (lubrication) fluid to help with smooth motion. Thigh muscles are important secondary knee stabilizers.

Investigations/Diagnostic Testing

A routine X-Ray of the knee, which includes a standing weight-bearing view is usually a requirement.  An MRI scan which looks at the cartilage and soft tissue may make the diagnosis more clear.  There is little value in the use of Ultrasound in investigating knee problems.

Meniscal Cartilage Tears

Following a twisting type of injury the medial (or lateral) meniscus can tear. This results either from a sporting injury or may occur from a simple twisting injury.  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.  On the inside or outside of the knee.
• Knee swelling.
• Poor motion.
• Locking if the cartilage gets in-between the femur and tibia.

Knee Joint Arthroscopy for Cartilage Tears

Once a meniscal cartilage has a tear, it will not heal unless it is a very small tear that is near the capsule of the joint. Once the cartilage has a tear, it predisposes the knee to develop osteoarthritis (wear and tear). It is better to remove torn pieces from the knee if the knee is symptomatic.

Torn cartilages in general continue to cause symptoms of discomfort, pain and swelling until the loose pieces are taken out.  The MD will remove the torn section and the knee should recover and become symptom free.  Removal of the entire meniscus will  usually result  in the development of knee osteoarthritis. 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, as long as the knee is stable and the tear is a certain type of tear in a young patient, the meniscus may be suitable for repair. A knee with a repair of the meniscus, must avoid sports for a minimum of three months.

Articular Cartilage (Surface) Injury

If the surface cartilage has a tear, this is most significant as a major shock-absorbing function is gone.  Large pieces of articular cartilage can float in the knee (sometimes with bone attached) and this causes locking of the joint.  This 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 and swelling due to cartilage peeling off can be helped with arthroscopic surgery. The surgery smooths 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 the ACL has a tear, it does not heal and usually causes knee instability.  It would be very difficult to to return to normal sporting activities. An ACL reconstruction is the best choice and a new ligament replaces the ruptured ligament. The arthroscope is how this procedure is currently done.

Patella (knee-cap) Disorders

The arthroscope can be used to treat problems relating to kneecap disorders.  Particularly mal-tracking and significant surface cartilage tears. Patients may need to stay overnight for a lateral release as knee swelling is quite common. The majority of common kneecap problems can be treated with physical therapy and rehabilitation.

Inflammatory Arthritis

Occasionally arthroscopy can be helpful with inflammatory conditions (e.g. Rheumatoid Arthritis) to help reduce the amount of inflammation in the synovium (joint lining) that is producing excess joint fluid. This procedure is known as a synovectomy. After the surgery, the surgeon will place a drain into the knee.  Patients generally require one or two nights in hospital.

Bakers Cysts

Baker’s cysts or popliteal cysts are often present 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.

New Knee Joint Arthroscopy Technology 

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.

Autologous Chondrocyte Grafting is the new area of knee repair surgery.  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 the cells are then put back into the knee in 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 return to normal function. There is however a small 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 5 days prior to your surgery. You can continue taking all your other routine medication. If you smoke you are advised to stop a few days prior to your surgery. You will be admitted on the day of surgery and need to remain fasted for 6 hours prior to the procedure. The limb undergoing the procedure will be marked appropriately prior to the anesthesia application.  Once you are under anesthetic, we prepare the knee in a sterile fashion. A tourniquet is placed around the thigh to allow a ‘blood – free’ procedure. The Arthroscope goes 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.

Post-operative Recovery

You will wake up in the recovery room and then transfer back to the ward. A bandage will be around the knee which we did surgery on. Once you are feeling better, the nurse will remove your IV.  They will show you a number of exercises to do. Your Surgeon will see you prior to discharge and explain the findings of the operation.

Pain medication will be provided and should be taken as directed. You can remove the bandage in 24 hours and place waterproof dressings (provided) over the wounds. It is NORMAL for the knee to swell after the surgery. Elevating the leg 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 are able to drive and return to work when comfortable unless otherwise instructed. Please make an appointment 7-10 days after surgery to monitor your progress and remove the 2 stitches in your knee.

Risks of Arthroscopy

General Anesthetic risks are extremely rare. Occasionally patients have some discomfort in the throat as a result of the tube that supplies oxygen and other gasses. Please discuss with the Specialist Anesthetist if you have any specific concerns.

Risks related to Arthroscopic Knee Surgery Include:

• Postoperative bleeding.
• Deep Vein Thrombosis (DVT).
• Infection.
• Stiffness.
• Numbness to part of the skin near the incisions.
• Injury to vessels, nerves and a chronic pain syndrome.
• Progression of the disease process.

The risks and complications of arthroscopic knee surgery are extremely small.  However, one must bear in mind that occasionally there is more damage in the knee than initially thought.  This may affect the recovery time. In addition, when 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 necessary in the future. In general, arthroscopic surgery typically does not improve knees that have well established Osteoarthritis.

Post-Operative Exercises and Physical Therapy

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? Approximately 4 hours.
• Do I need crutches? Usually not required (Unless you are having Anterior Cruciate Ligament Reconstruction).
• When can my knee become wet? After 24 hours remove the bandage and apply a waterproof dressing.
• When can I drive? After 24 hours if the knee is comfortable.
• Returning to work? When the knee feels reasonably comfortable.
• Swimming? After removal of the stitches.
• How long will my knee take to recover? Depending on the findings and surgery, usually 4 to 6 weeks following the surgery.
• When Can I return to Sports? Depending on the findings, 4-6 weeks after surgery.

Finally, to schedule for JOI Rehab for Physical Therapy, please call 904-858-7045. 

Related Knee Articles:

• Anatomy of the knee
• Content knee anatomy
• Knee ligaments
• Knee anatomy

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