Arthroscopic knee surgery, also known as knee arthroscopy, is a minimally invasive procedure for diagnosing and treating injuries and illnesses of the knee joint. This involves inserting a camera and special instruments into the joint via small incisions in the skin. This means damage can be treated in a targeted manner without opening up a large area of the joint. As a result, the strain on the body is lower and it generally heals faster than with open surgery.

Hirslanden Orthopaedics, Anatomy of the knee
Image caption
1. femur
2. patellar tendon
3. kneecap
4. cartilage
5. cruciate ligaments
6. medial ligaments
7. meniscus
8. lower leg bone

The knee joint at a glance

The knee joint is the largest and one of the most complex joints in the human body. It connects the thighbone (femur) with the shinbone (tibia) and the kneecap (patella). Structures such as the menisci, cruciate ligaments, lateral ligaments and cartilage ensure stability, mobility and effective shock absorption.

Injuries, inflammations or signs of wear and tear can cause pain and restricted movement. Knee arthroscopy enables the precise diagnosis and targeted treatment of these complaints.

 

Treatment goal

The aim of arthroscopic knee surgery is to improve or restore the mobility and function of the knee joint. The most common indications for knee arthroscopy are:

Procedure for arthroscopic knee surgery

The exact procedure for knee arthroscopy depends on the diagnosis and the necessary treatment. In most cases, the intervention is performed on an outpatient basis. It is usually carried out under spinal anaesthesia, but in some cases general anaesthesia may be required.

A thin optical instrument with a camera (arthroscope) is inserted into the knee joint via a small incision, while another incision allows access for surgical instruments. During the entire intervention, the joint is rinsed with a sterile fluid to expand the joint space and ensure optimal visibility. The next steps vary depending on the type of injury or illness:

Meniscus surgery

Small tears (third degree) in the meniscus can often be remedied by meniscal debridement (meniscus shaving), in which damaged tissue is smoothed. In certain cases, meniscus suturing is carried out in order to preserve the tissue and preserve the most natural joint function possible. However, if the meniscus is more damaged and can no longer be saved, partial or complete removal (meniscus resection) may be necessary.

In these cases, the meniscus is replaced with a collagen meniscus implant. Broken cartilage or bits of bone can also be removed arthroscopically.

Cruciate ligament surgery

Injured cruciate ligaments can either be stitched in a knee arthroscopy or, if necessary, replaced with a tendon taken from elsewhere in the patient’s body. The anterior cruciate ligament (at the front of the knee) in particular is often reconstructed, as it is essential for the stability of the knee joint. Parts of the patella tendon or quadriceps tendon are usually used as grafts. Sometimes a tendon must be removed from the other knee by means of arthroscopy for the ligament replacement.

Synovectomy

In some cases, if the joint capsule or joint mucous membrane (synovium) is chronically inflamed, the inflamed mucous membrane may need to be surgically removed. This intervention, known as synovectomy, can be performed in a minimally invasive manner as part of a knee arthroscopy.

Cartilage damage

Minor cartilage damage is treated by smoothing out rough or damaged surfaces in order to restore the smooth sliding of the joint surfaces against each other and improve joint function. For more serious damage, regenerative procedures such as microfracture or cartilage transplantation are used. This involves either stimulating the formation of replacement cartilage or transplanting the body’s own cartilage tissue.

Loose bodies in the joint

Loose bodies in the joint, also known as joint mice, can be removed during a knee arthroscopy. These loose pieces of bone or cartilage in the joint can cause pain or locked knee. Through small incisions, the surgeon inserts an arthroscope and special instruments to locate and remove the loose bodies. This minimally invasive intervention enables rapid recovery and restoration of joint function.

Bursectomy

In cases of chronic or recurrent knee bursitis, an arthroscopic bursectomy may be performed. This is a procedure to remove the inflamed bursa (one of the fluid-filled sacs in the joint). The intervention involves making small incisions through which the surgeon inserts the arthroscope and special instruments. Removing the inflamed bursa can reduce pain and improve knee mobility. After the intervention, a new, healthy bursa usually forms.

Locked knee joint

Locking of the knee joint can have various causes, such as parts of the meniscus becoming trapped, or loose joint bodies. The aim of the arthroscopic intervention is to identify and remove the cause of the locking. Depending on what the surgeon finds, the rest of the procedure may include removing or smoothing a trapped portion of the meniscus, removing free joint bodies or loosening adhesions.

Preparation and prevention

Before the intervention, the knee joint is examined in detail using X-ray imaging or an MRIs can to determine the extent of the injury or disease and to select the appropriate treatment method. In addition, an individual risk assessment is carried out, in which pre-existing conditions, medications and potential risks of complications are taken into account in order to make the intervention as safe as possible.

For the surgery, it is also important to fast, i.e. not to eat solid food for at least six hours before the intervention and not to drink fluids for up to three hours before the procedure. Blood-thinning medications must be stopped a few days beforehand in consultation with the attending doctor. In addition, blood tests, an electrocardiogram and a blood pressure test can be carried out before the surgery to check the patient’s state of health and rule out any possible risks.

Aftercare and recovery

Follow-up treatment depends on the type of injury and the intervention performed. After minor arthroscopic interventions, the patient can often put weight on the knee shortly afterwards. For more extensive surgeries, such as cruciate ligament reconstruction or meniscus resection, a longer recovery period is required before the joint is fully resilient again. In such cases, healing can take up to three months. Progress is monitored regularly in check-ups to ensure optimal recovery.

As a minimally invasive procedure, arthroscopy is much more gentle than open surgery. It reduces the strain on the joint and enables faster recovery. Thanks to its high success rate, it is considered the standard method for treating meniscus injuries and cruciate ligament tears.

Potential complications

Arthroscopy of the knee joint is considered a safe and low-risk routine procedure. Nevertheless, as with any surgery, complications can occasionally occur. These include infections, nerve injuries, secondary bleeding or blood clots (thromboses).  Sometimes joint effusions (fluid build-up) can occur after the intervention, which must be treated by arthrocentesis (withdrawing some of the fluid via a needle). In rare cases, a regulatory disorder of the vessels and nerves may occur, known as Sudeck’s syndrome.

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