Knee Cartilage (Meniscus) Tear
Overview
The knee has two types of Cartilage – Articular Cartilage and Meniscal Cartilage.
The Articular Cartilage is the cartilage that lines the bones, to ensure smooth movement of one bone on the other. If the Articular Cartilage thins out or dissolves, this eventually results in painful bone rubbing on bone – and this is called end stage arthritis.
The knee also has Meniscal Cartilage. There is an inner (or medial) meniscus and an outer (or lateral) meniscus. Usually when friends say they “tore their cartilage”, they are usually referring to the Meniscal Cartilage.
The functions of the Meniscal Cartilage are load bearing, shock absorption and knee joint stability. Thus removing any portion of the Meniscal Cartilage is not ideal. However, if the meniscal cartilage is torn and causing pain or obstructive symptoms (locking, catching, etc.), then removal of the torn, unstable segment is typically recommended. This is done via a keyhole or arthroscopic technique.
Typically the unstable portion of the Meniscal Cartilage is removed using a suction/shaver device in the knee. The goal is to remove the unstable portion, while preserving as much normal Meniscal Cartilage as possible. On rare occasions, the torn Meniscal Cartilage can be repaired (as opposed to shaven out). Repairs are only used in certain tear types, in younger patients. If a meniscal repair is undertaken, the post-operative treatment will be different.
It is important to note that Meniscal Cartilage tears seen on MRI scans are not always the cause of knee pain! Thus I take a careful history and perform a complete examination prior to suggesting a knee arthroscopy.
The literature tells us that the factors predictive of a less favourable outcome after Meniscal Cartilage surgery are female sex, outer (lateral) meniscal cartilage tears, > 50% meniscal resection, patients being over-weight or obese, knees with pre-existing Articular Cartilage damage and unstable or mal-aligned knees.
Non-Surgical Treatments
After the initial traumatic event, it is best to see if the intermittent pain settles itself over a number of weeks. A physiotherapist may be helpful in the acute phase. If the darting pain persists for more than 6 weeks, surgery may become necessary.
Surgical Treatments
Knee Arthroscopy
A knee arthroscopy is when a camera and instruments are inserted into the knee joint. This is a “key-hole” type operation, which is performed as a Day Case procedure, meaning you come in the morning and go home in the evening. The operation is performed under a General Anaesthetic, meaning you will be fast asleep. While you are asleep, I will make two small incisions on the front of your knee. Through one incision I place a camera, to allow me to look all about the knee joint. Through the second incision, I place an instrument, typically a hoover device, to shave out any loose fragments or tidy up meniscal or articular cartilage tears.
It is important to note that approximately 10% of patients will have residual discomfort and swelling in their knee for up to 6 weeks after the surgery. This might arise because the knee became inflamed after the surgery or because lots of force had to be used to open the different compartments, to enable access to address problems. You may need an anti-inflammatory for the 6 week period.
Complications following knee arthroscopy are rare but include infection, residual swelling and soreness needing anti-inflammatories, persistent pain, further meniscal tearing, venous clotting, nerve injury and general medical complications. One of the aims of surgery is to remove any loose, unstable pieces of cartilage, but also to preserve as much stable cartilage as possible, as the more meniscal cartilage removed, the greater the risk of developing joint arthritis in the long-term.
Surgery – What to expect?
Knee arthroscopy is performed as a day-case procedure. Following the operation, our Whitfield physiotherapists will show you photos of the inside of your knee and explain what was done during the operation. You will be helped out of bed and shown how to use crutches. Everyone goes home on two crutches, but you can drop the crutches, once you feel confident yourself. Most people are off the crutches within one week. Our physiotherapists will give you a 6 week exercise programme.
Following the arthroscopy, you will need Paracetamol and an anti-inflammatory for a number of days. You can reduce your dressings the following day and ask your GP to remove your sutures over the next 7 – 10 days.
Your return to work date very much depends on your occupation. If you work in an office based environment, you might return to work within 3 days, however if you are a busy dairy farmer for example, you might need 3 weeks off work. Your exact return to work date is a little unpredictable.
The return to sport date after meniscal cartilage surgery depends on many factors, including your sport, your position and is always slower if the outer (lateral) meniscus was injured.
I see everyone again 6 weeks after their surgery, to assess the response to the arthroscopy, or sooner if there were any concerns.