Knee arthroscopy is one of the most commonly performed orthopaedic operations in Australia today. It is used to help diagnose and treat many different conditions, and may form a part of other operations.
The term “arthroscopy” is derived from the root words “arthro”, meaning “joint”, and “scopy” meaning to look with a video camera. For knee arthroscopy the camera is about the size of a pencil, so can be inserted through very small incisions whilst allowing excellent visualization of all the internal structures of the joint. Similarly sized, thin instruments can be inserted via another incision to repair or excise parts of these structures.
The indications for the procedure vary with the suspected or confirmed pathology. For more information view Knee Conditions.
Common indications include:
- Mechanical symptoms such as locking from a torn meniscus.
- Septic / infective arthritis or acute inflammatory conditions such as gout.
- Loose pieces of bone or cartilage for removal.
- As part of knee ligament reconstruction.
Of note, there has been some debate recently over the value of knee arthroscopy in the case of degenerative osteoarthritis with or without meniscal tears.Certainly, as the arthritic changes become more severe, the less likely knee arthroscopy is going to be helpful. However, in some cases where symptoms have appeared suddenly or there is a clear mechanical issue, there is still a place for knee arthroscopy even in older patients.
The specifics of the preoperative work-up will be discussed with you at the time of booking your surgery. Some points to note include:
- The procedure is usually performed as a day case in an operating theatre under anaesthesia.
- You will need to fast for a minimum of 6 hours prior to admission to the hospital.
- Ensure you bring all relevant imaging with you if available.
- You will not usually require crutches afterward.
The operation is carried out as a day case procedure. A general anaesthetic is given and it typically takes around 30 minutes. Two small incisions are made on the front of the knee, the camera is used through one, instruments through the other. The knee is filled with fluid to aid visualization and all internal structures inspected.
In the case of tears of meniscus (a fibro cartilage “shock absorber” or “washer” in the knee), the tear is inspected to see if it is repairable or not. Repairable tears are not common. If it can be repaired, special sutures (either all internal or a combination of internal and external) sutures are used to sew it together. More often it is not possible to repair, so the torn segment is excised. See Anatomy of the Knee.
The meniscus clearly has an important protective function for the knee, so as little as possible is removed. Although this is not ideal, a torn meniscus is also not performing this protective function, so whether a torn segment is removed to relieve pain, or left alone, the long term risk of arthritis in the knee as a result, is the same.
Other types of pathology require different treatments. Mr Callahan will discuss these with you prior to the surgery.
At the end, the wounds are closed with steri-strip dressings only (or occasionally stitches), waterproof dressings are applied, local anaesthetic injected into the joint and the knee wrapped in bandages.
After surgery, the knee will usually have very little pain due to the local anaesthetic in the joint. You may go home once recovered from the general anaesthetic. You will be given instructions on caring for the knee at that time. You may walk on the leg, but remember not to do too much the first day. The local anaesthetic may well be giving a false sense of well-being and as it wears off there will be some pain in the joint. Pain relieving medication will be provided.
The outer bandages may be removed after 2-3 days. Some patients prefer to wrap them on again for support. You may shower without the bandage. Gently start some movement exercises and increase activity only carefully within the limits of pain
At 10-14 days you will be seen and the wounds checked and dressings removed. Although it is possible to start returning to more vigorous activity after this point, it is important to remember that the knee will still swell and ache for a few more weeks if you do too much.
Most patients are well recovered and back to most activities after 3-4 weeks. Running and sport may take longer, and it is variable depending on how much and what type of surgery has been done and the extent of untreatable degenerative changes in the knee.
All surgery carries with it some form of risk. Common risks that apply to all surgery, including knee arthroscopy, are...
- Formation of a blood clot (“DVT” or deep vein thrombosis) Pieces of clot in the leg can break off and lodge in the lungs causing a pulmonary embolism. This can be very serious, and in rare cases even cause death.
- Nerve damage.
- Difficulty getting the wound(s) to heal.
- Abnormal pain reactions or nerve hypersensitisation known as complex regional pain syndrome (CRPS).
Risks specifically related to this procedure include...
- Incomplete relief of the pain or inability to treat all conditions identified.
- Persistent leakage of fluid from the knee via the incisions.
- Injury to vessels, nerves and tendons around the knee- There are some very important structures at the back of the knee which theoretically could be injured by surgery.