Meniscal injuries are one of the commonest problems that I see as an orthopaedic surgeon specialising in knee injuries. The meniscus is perhaps more commonly referred to as the knee ‘cartilage’.
It is not unusual to hear of professional sportsmen and women sustaining ‘cartilage injuries’, but it may come as a surprise to know that the majority of my patients tear their cartilage undertaking relatively common day-to-day activities.
For this reason not unsurprisingly, it often doesn’t occur to the patient or their family doctor that they may have torn a cartilage even when they present with persistent intermittent knee pain.
A significant twisting injury sustained for example whilst playing football or skiing may well result in a meniscal tear but equally even day to day actions such of getting up from sitting on the floor for example in a in a yoga class can produce exactly the same result, especially in the older age group. (I am sorry to say that in orthopaedic terms, the phrase “older age group” sadly refers to patients over 40!) After this age, the cartilage has already started to turn from a very resilient, tough rubbery construct to a more brittle one. It is for this reason that a simple twisting injury can cause a small split within the cartilage. The meniscus has a very limited capacity to heal by itself because the vast majority of it doesn’t have a blood supply. This means that symptoms from a torn cartilage will often persist long after one would expect other injuries to have healed, leading the patient to seek specialist advice for a pain that doesn’t seem to be “getting better”. It is not unusual however for the sharp pain to die down after several weeks only for it to return each time a return to sport is attempted.
Every knee has two menisci within it, one on the inner (medial) aspect of the knee and one on the outside (lateral). These are commonly known as “the knee cartilages”.
The three main functions of the menisci are:
The diagnosis is based on a combination of consultation findings, examination and imaging.
Whilst the story patients will often give of a classical sporting injury is relatively self-evident, where there has been no clear memorable history of injury to the knee that can be remembered, making the diagnosis can be much more challenging. Listening to your history is, however, usually very helpful. Some classical symptoms for meniscal injury include some or all of the following:
Pain from a torn cartilage may vary between a sharp stabbing pain and a dull ache; it may be intermittent or continuous. Occasionally, there is no pain at all associated with these injuries but simply an inability to completely straighten the leg. This is referred to as a Locked knee.
Examination may reveal the following tell-tale signs of a meniscal tear, such as:
After an initial examination, I will normally refer you for an MRI scan when investigating meniscal damage. Magnetic resonance scans produce high resolution images of the soft tissues in and around the knee. The high degree of definition within these scans allows the Radiologist to identify a tear within a meniscus with a high level of accuracy (98%) and thereby confirm or refute the clinical suspicion. MRI scans which rely on the use of very strong magnetic fields are not only much more detailed than X-ray or CT scans, they also require no radiation to the patient, which is an additional benefit.
Due to the absence of a blood supply to most of the meniscus, a tear is unlikely to heal by itself. Sometimes the symptoms appear to settle, but this is often short-lived. Where the pain persists, the first thing to stress is that surgery is always a last resort, even when there is a proven cartilage tear. It is always the patient’s symptoms which should lead the surgeon and the patient to consider an operation rather than just the presence of an MRI-proven tear alone. This is because some patients will have an incidental meniscal tear, which is not responsible for their symptoms. Moreover, when a patient with a known meniscal tear has other conditions affecting the knee such as osteoarthritis ( wear and tear) then surgery is less likely to be successful and as such this should influence the decision to operate. In older patients (over 60), we know that the lining of the articular surface of the joint may already be significantly diminished (osteoarthritis). Surgery to treat a meniscal tear may not only fail to treat the symptoms of patients in this age group, but can, sometimes, actually aggravate the knee further. Clearly, this can be disappointing for both patient and surgeon alike. It should never be forgotten that surgery has the ability to make you worse as well as better. Therefore, the decision to proceed to surgery must always be preceded by careful discussion with consideration of all the options available including the option to wait and see.
If the decision has been made to proceed to surgery, this is a procedure known as an arthroscopic partial meniscectomy. This is a relatively straightforward keyhole operation carried out under general anaesthetic, lasting up to half an hour. The patient will need to:
The operation involves the insertion of a lens camera system or “arthroscope” into the knee through a 4mm incision or “portal” in the front of the knee. The keyhole instruments are similarly introduced into the knee through another 4mm portal in order to cut away the torn/damaged part of the cartilage. As little of the cartilage is removed as possible in order to preserve the function of the remaining healthy portion. Usually approximately 20-25% of the cartilage needs to be excised. Once the whole of the inside of the joint cavity has been thoroughly inspected and any other defects/damage noted, the instruments are removed and the portals closed with nylon sutures.
The knee is dressed with a woolen bandage which will be removed before you are sent home later that afternoon and you will be encouraged to walk almost immediately that afternoon, but only for short periods initially.
After the first few days, you will be able to stand and walk as comfort allows. The use of crutches is strongly discouraged as they interfere with the normal walking pattern.
Any pain is normally controlled with a combination of anti-inflammatory drugs and painkillers, which may include simple paracetamol as well as some codeine and or anti inflammatory medications such as Ibuprofen. Physiotherapy should start within a few days of your discharge.
Physiotherapy plays a vital part in post-operative recovery. It is important to work with a physiotherapist who not only has an interest in knee surgery but is also geographically convenient for you after surgery. I normally see patients at two weeks post operation to check their wounds and to remove the stitches for them. I expect you to be making good progress by this stage, but not to be fully recovered. Generally, full recovery takes about six weeks, but most patients can return to work within the first week. However, attempting to do too much early on, in my view, can often be a bad thing, irritating the sensitive remnant of the meniscus. It is very important for the knee to be given appropriate care and respect in the early stages including regular icing. If you are returning to work, do ensure that travel arrangements are adapted to reduce the amount of time spent walking, particularly if public transport is being used. It is inevitable that patients will recover at different rates but there is no such thing, in my opinion, as minor surgery, especially when dealing with an invasive procedure under general anaesthetic in a cavity of the knee.
Sadly, in my view, there is a temptation by some doctors to trivialise this sort of surgery, but, as anyone who has had the operation will tell you, the recovery process will last for several weeks causing disruption to normal daily life during this time.