Having talked to you about the symptoms that you experience and examined your knee, your specialist Consultant surgeon will have come to a diagnosis and discussed a treatment plan with you. X-ray images are commonly taken and an MR scan may also have been performed (but this is not always necessary). From these sources of information, your Consultant will have suggested an arthroscopic examination of your knee under an anaesthetic and often a further procedure using arthroscopic techniques at the same time.
An arthroscopy operation is commonly known as a “keyhole operation” or “minimally invasive procedure”.
What happens during a knee arthroscopy? You will require an anaesthetic for your surgery. This may either be a general anaesthetic (where you are asleep) or a spinal anaesthetic (where an injection is given into the back to “freeze” the lower half of the body, keeping the rest of you awake). For further information on anaesthetics, see the leaflet “You and your anaesthetic” in the anaesthetic section of the web site. If you are awake for the surgery, you may be able to watch the procedure on the television screen whilst your surgeon is operating.
You will lie on your back whilst your Consultant performs the procedure, no matter what type of anaesthetic you have. A pneumatic tourniquet is often inflated around the thigh to shut off the flow of blood during the procedure. This improves the view of the inside of the joint for the surgeon. The affected knee is bent and two small, 5-8mm, incisions are made on either side of the large tendon below the kneecap. For some more complicated procedures, other incisions are also required around the knee. These short incisions are called “portals” and allow specially designed arthroscopic instruments to be inserted into the cavity of the knee joint.
The first instrument to be inserted into the joint is the camera. This is often called a “telescope” as it is a long, thin, tubular instrument, 4.5mm wide containing lenses. It is passed through a sheath into the knee.
The sheath allows fluid (a salt solution) to be passed into the joint. The fluid distends the joint, allowing a better view. It also allows debris from certain surgical procedures to be washed out of the knee along with any blood. Other instruments including a simple probe, hand instruments, motorised instruments and radiofrequency or electrical cautery probes may also be used.
At the end of the operation, a stitch or steristrips will be put across each of the portals to close them and special sticking plasters will be put over these. A soft bandage will be wrapped around the knee and a splint may be applied in some cases.
Which procedures may be performed at a knee arthroscopy? Originally, knee arthroscopy was used mainly for diagnosis of knee problems. Now, a wide range of therapeutic surgical procedures are carried out arthroscopically. A selection of the commonest procedures follows:
Menisectomy (removal of a torn knee cartilage)
Meniscal repair (repair of a torn knee cartilage)
Debridement (cleaning out) of an arthritic joint
Microfracture of a small arthritic area of the joint
Plica excision (removal of a fold of tissue that is catching in the joint)
Synovectomy (removal of the lining of the joint)
ACL reconstruction (reconstruction of one of the main knee ligaments)
There are a number of other procedures of varying complexity that may also be carried out arthroscopically. The time taken for procedures varies between 15 minutes and a couple of hours depending on the complexity of the operation.
What are the benefits of a knee arthroscopy? As the tissues of the knee are disturbed relatively little by minimally invasive surgery, there is less reaction of the body to the surgery and much smaller wounds to heal. This tends to allow faster rehabilitation and often less pain and dysfunction after the surgery than would otherwise be experienced. The amount of bleeding is reduced as is bruising and swelling compared to traditional, open surgery. For some procedures, the view of the inside of the joint is better than at open surgery.
What are the risks of a knee arthroscopy? Knee arthroscopy is not generally deemed to be a high-risk procedure in itself.
Risks of anaesthesia: Please see the information on “you and your anaesthetic” in the anaesthesia area
There are some general risks of lower limb surgery. These include:
Swelling and stiffness of the knee
Bleeding & bruising
Deep vein thrombosis (DVT) and a small chance of pulmonary embolus (PE). The latter may be fatal in 1% of cases in which it occurs but fortunately this is very rare after arthroscopy.
Incomplete symptom relief
Recurrence of symptoms
Nerve and / or blood vessel injury
Infection has a rate of under 1%. A dose of intravenous antibiotics may be given to reduce this risk at the start of surgery.
To reduce the risk of DVT & PE, compression (TED) stockings may be prescribed for wear postoperatively for up to 6 weeks. It is also important to stay well hydrated and to keep as mobile as possible after surgery. The risk of DVT/PE is assessed by a questionnaire before surgery.
In those who are assessed as having a higher risk of DVT/PE, heparin injections under the skin of the abdomen may be prescribed for a period after surgery.
Specific risks associated with knee arthroscopy
Synovial fistula – a rare complication where joint fluid leaks out of the knee
Late onset knee arthritis after menisectomy
Prolonged physiotherapy rehabilitation
What happens after the surgery? To a large extent this depends on which type of arthroscopic operation you have had. Your Consultant will advise you when you may return to work, driving and sporting activities.
Stitches are usually removed from the portals at 10-14 days after your procedure and this is frequently arranged at your GP’s surgery.
Physiotherapy is often arranged after your surgery to improve the range of movement of your knee, prevent stiffness and specifically build up muscle groups that will enhance the function of your knee. It is very important that you closely follow the physiotherapy programme, doing exercises at home every day as advised by your physiotherapist and surgeon. A failure to do this will slow your recovery and may not allow you to gain the best results from your surgery. The frequency of visits to the physiotherapist is variable and depends on the type of surgery and how you are progressing and the time from your surgery. It can vary from three visits per week to one per month. Cooling the knee with an ice pack may also be helpful postoperatively.
We hope you have found this information useful. Please feel free to ask your Consultant surgeon questions on areas of your treatment that you are not clear on.