I often talk to patients who are considering surgery for a particular injury. I am neither pro- nor anti- surgery in general; I think it largely depends on the patient's individual circumstances. It may be the right option for some people with some injuries, but entirely the wrong choice for others; and it's a decision that needs to be made carefully in consultation with the doctors and specialists involved.
It concerns me, though, when patients are given a misleading impression by click-bait articles like, for example, this one which claim that "surgery is a waste of time and money for knee pain patients". If you’re currently considering some kind of knee operation, this sort of headline might be enough to make you think twice. After explaining to a few people that actually it was a great deal more complicated than that, I wrote this article so that I wouldn't have to keep repeating myself.
Let’s start with what what we mean by “knee surgery”.
"Knee surgery" isn’t a thing.
If we’re going to look at the research properly, then it’s important that we’re very clear what we’re actually talking about. “Knee surgery” covers a whole range of different procedures for different problems and lumping them all together won’t help us to figure out what works and what doesn’t. Worse still, it’s often the case that a particular study focuses only on one kind of procedure, but that detail gets lost somewhere between the press release and the final news report (or is only mentioned briefly towards the end of the article). This is a little bit like dropping a dozen toasters off your roof, and then proclaiming that “machines can’t fly”.
The other problem is that no two patients are exactly the same. Even if you’re looking at the same procedure, it’s likely that it will be more effective for some people than others. The difference may depend on the severity of their injury, their age, lifestyle and activity level. It’s often hard to know in advance which patients will benefit the most from a particular intervention - it may be that some get better, but others get worse. Some research attempts to find factors that help to predict who will benefit from the surgery, or restrict their attention to a group of patients with very specific characteristics; other studies look at the overall outcomes across a wider range of patients. Without taking a close look at the research literature, it’s tricky to know how to interpret many of these findings, and even the experts often reach different conclusions from the same evidence.
What is the evidence being reported on?
The most common kind of knee surgery that’s been under scrutiny over the last few years is arthroscopic (keyhole) surgery for meniscus (cartilage) tears. So, to keep things straightforward, let's focus on this and leave aside the many other procedures such as knee replacements or ligament reconstructions.
One study that led to some of the headlines was a systematic review published in the British Medical Journal in 2015. It focused on surgery in “middle aged or older” patients with knee pain and degenerative knee problems. The review looked at nine original studies that met the authors’ criteria, and it found that overall, there wasn’t much benefit from surgery compared to other interventions, such as anti-inflammatories or exercise therapy. It didn’t take into account whether or not there were “mechanical symptoms”, such as joint locking; this means that it’s unclear from this study whether or not surgery will be more helpful for these patients. In practice, many specialists do take this into account when making decisions about treatment and some argue that it's an indication that surgery is needed.
What about acute injuries?
How do things differ if you’re a young, active person and your meniscus tear isn’t the result of general wear and tear, but occurred in an accident or sports injury?
There’s little research that looks at non-operative management of acute meniscal tears in younger age groups. Whether or not you should try conservative (non-surgical) treatment first is likely to depend on how stable the tear is. A stable tear may settle down by itself, whereas an unstable one can allow the meniscus to move abnormally and may continue to cause problems or progress further.
If surgery is considered, much will depend on the nature of the tear itself. In the past, it was common to remove the whole of the meniscus, but studies have shown that this generally leads to altered biomechanics of the knee, osteoarthritic changes and increases the likelihood of future problems. Nowadays, more emphasis is placed on trying to preserve the meniscus if possible, either by repairing it, or by removing only part of it. Evidence suggests fairly good results for partial meniscectomy in younger patients (under 40) who don’t have degenerative changes or other accompanying problems (such as tendinopathy or ligament injury).
Although there are particular cases where knee surgery can do more harm than good, there are other problems for which it is likely to be much more helpful. It’s important to consider each case on its individual merits, and to look carefully at the research that’s most relevant to your own situation instead of just reading the headlines.
Whether or not to have surgery can be a difficult decision, and unfortunately there isn’t always an easy answer, so don’t be afraid to get opinions from several different specialists before you make up your mind. In general, if your symptoms are manageable and (in the view of your specialist) the problem is unlikely to be made worse by waiting, then it may well be worth trying a program of conservative treatment (including exercise therapy) before deciding to go ahead with an operation.