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Anatomy of the knee joint

The knee joint consists of three bones: the femur, the tibia (shinbone) and the patella (kneecap). The patella sits at the front of the knee, on top of the femur, and slides down into a "groove" as the joint bends. It enhances the function of the quadriceps muscle.

The contact surfaces of the three bones are covered with articular cartilage - a tissue that provides smooth movement of the joint with a low coefficient of friction. The cartilage, together with the menisci, act as the "shock absorbers" of the knee joint.

Ligaments are strong, elastic structures made of collagen that connect bones and provide stability to the joints.

Four main and several smaller ligaments connect the femur to the tibia:

• Anterior cruciate ligament - ACL - located in the middle of the joint and mainly prevents the tibia from shifting forward and sideways relative to the femur.
• Posterior cruciate ligament - PCL - located inside the joint and mainly prevents the tibia from shifting backward relative to the femur.
• Fibular (lateral) collateral ligament - located on the outer side of the knee and protects the tibia from shifting relative to the axis of the lower limb.
• Tibial (medial) collateral ligament - located on the inner side of the knee and protects it from shifting relative to the axis of the lower limb.

The menisci are located between the two large bones in the knee joint. There are two of them - the medial meniscus (inner) and the lateral meniscus (outer). These are crescent-shaped cartilages. The medial meniscus is large and fused at its periphery with the joint capsule and the tibia, while the lateral meniscus is small and free, attached only to the tibia. The menisci distribute 60% of the load in the knee joint at various degrees of knee flexion, reducing the contact area of the cartilage surfaces. They also play an important role in joint stability during all of its movements.

Cartilage tissue is a fundamental structure in all joints, including the knee, and its condition plays a leading role in all joint functions.

About knee arthroscopy

Knee arthroscopy is most often used to diagnose and treat problems such as inflammation, injury, trauma, degenerative issues and others. It can also be used to take a biopsy to clarify the cause of less common conditions (gout, rheumatoid diseases, tumor processes, etc.).

Arthroscopy is useful for the evaluation and treatment of the following conditions:

• Meniscus tear
• Articular cartilage injury
• Removal of loose bodies and cysts
• Reconstruction of the anterior and posterior cruciate ligaments (ACL and PCL)
• Patellofemoral pain syndrome
• Inflammation of the knee joint
• Diagnosis and treatment of degenerative (age-related) changes in the knee
• General diagnostic purposes

Preparing for the procedure

1 week before surgery:

• You may need to stop anticoagulant medications (aspirin, Sintrom, etc.)
• Ask your doctor which medications you are allowed to take on the day of surgery
• You should not consume large amounts of alcohol (more than 1-2 drinks per day)
• If you smoke, it is recommended that you stop, as smoking can slow healing
• Inform your doctor of any cold, flu, fever, herpes or other illness you have had shortly before the surgery

On the day of surgery:

• You will be asked not to eat or drink for 6-12 hours before the procedure;
• Take your prescribed medications with a small sip of water.

After the procedure:

Most patients go home the same day as the surgery. You may need painkillers to manage the discomfort of the anesthesia wearing off.

It is a good idea to arrange in advance for a family member or friend to drive you home. It is best to have someone with you for the first 24 hours.

You will be given some advice on how to care for healing wounds. You will also be scheduled for follow-up check-ups (usually on day 7 and day 12).

The time it takes for self-dissolving stitches to disappear depends on your condition. However, with this procedure they usually disappear after about six weeks. Other stitches are removed between 10 and 14 days after the surgery.

What does knee arthroscopy involve?

Arthroscopy can last from 15 minutes to more than an hour, depending on the condition of the knee joint and what surgical procedures need to be performed.

There are four different types of anesthesia that can be used for knee arthroscopy:

• Spinal anesthesia - also called regional anesthesia. The pain-relieving medication is injected at a specific location around the roots of the spinal nerves. The patient remains awake but feels no pain from the waist down.
• General anesthesia - the patient is put to sleep via an intubation tube in the trachea and is unconscious during the procedure.
• PNB (peripheral nerve block) - the analgesic is injected along the course of the nerves responsible for the knee.
• Combined anesthesia - a local analgesic is administered to the knee and the patient is sedated intravenously.

The different anesthesia methods have their advantages and disadvantages, which are discussed between the anesthesiologist and the patient.

Once the anesthesia takes effect, the surgeon makes several small puncture incisions (4-5 mm) to access the knee joint. A special fluid is infused into the joint, after which the arthroscope (the micro camera) is inserted.

Using the arthroscope and a monitor, the surgeon examines all the intra-articular structures. Miniature instruments are used to repair damaged tissues or remove material that is obstructing movement or causing pain in the knee joint.

Once finished, the surgeon suctions the fluid from the joint and stitches the access points. A bandage is then applied around the knee.

Recovery

Recovery from knee arthroscopy is much faster compared to traditional open surgery. Still, it is important to carefully follow the instructions of your orthopedic surgeon. You may need to wear compression stockings, which help maintain circulation, as well as various orthotic devices (knee braces, splints).

It is important to keep your knee clean and dry for about 10 days after the surgery. Under no circumstances should you soak your knee in a bath until the wounds have fully healed.

Perform the exercises recommended by your physical therapist, as they will help improve movement and strength in the knee.

There may be pain and swelling in the knee, most often one to three weeks after the surgery. In some conditions (arthritis, degenerative changes, after microfractures, and after larger and more complex reconstructive surgeries), this may last longer. Try to keep your leg elevated above chest level on a chair or pillow when resting. A cold compress (ice wrapped in a towel) is recommended 3-4 times a day. This will help reduce swelling and bruising. It is advisable not to apply ice directly to the skin, as it may damage it.

Follow your doctor's advice regarding driving. You should not drive until you are confident that you can perform an emergency stop without feeling discomfort. This usually happens about one to three weeks after the surgery.

You should be able to resume your usual activities after six to eight weeks, depending on the severity of the problem and your fitness level (with the exception of ACL and PCL reconstruction surgeries and certain fractures).

Physical therapy

Strengthening the thigh muscles is most important. Swimming and cycling (stationary bike) are excellent ways to build these muscles and improve knee mobility.

Every patient is unique. The time needed for recovery depends on the type of injury, fitness level, and whether you have had complications. After knee arthroscopy, small scars will remain on the knee from the incisions.

Possible complications
According to the literature, the overall rate of possible complications from arthroscopy is under 0.5%. Most often they are minor and temporary (resolving completely within 5-7 days). Potential postoperative problems include:

• Infection
• Formation of blood clots
• Accumulation of blood in the knee

Call your orthopedic surgeon immediately if you experience the following:

• Fever
• Chills
• Persistent warmth or redness around the knee
• Persistent or worsening pain
• Significant swelling in the knee
• Increasing pain in the calf muscles

Advantages of knee arthroscopy

Unlike open surgery, arthroscopy results in less pain and stiffness, fewer complications, a shorter hospital stay (if any) and faster recovery.