Understanding Knee and Hip Replacements: What You Need to Know

When should I consider a knee replacement?

We tend to try to keep you away from surgeons as much as possible, so in general, you should only consider a knee operation of any sort if your knee is both causing pain and also, more importantly, stopping you from keeping healthy and active.

When the risks of surgery were great and the benefits less certain, we used to say ‘avoid surgery until the pain is unbearable’. But in 2025, we know that keeping active is perhaps the single most important bit of health maintenance entirely under your own personal control. If your knee is stopping you from enjoying life and keeping healthy, then it is worth finding out why and exploring the options.

When will you need to refer me for knee surgery?

If you are suffering from knee pain or instability of your knee, we will listen to your symptoms carefully, examine your knees and hips and watch you walk. Depending on the likelihood of knee surgery, we will then consider a referral either to a sports doctor to oversee rehabilitation or to an orthopaedic surgeon to consider surgery.

What should I expect at a knee surgery consultation?

Your surgeon will listen to your problem and understand it in the context of your general health and life. The examination will include a brief inspection of your back and hips, and your feet and ankles, before concentrating on your knees. The key question for the surgeon to answer is a simple one: is this problem just a ‘flat tyre’, ie a mechanical problem of a worn-out bit of cartilage, or is there a bigger problem – has a ligament parted as well, or are there signs of an inflammatory arthritis which might be affecting the whole joint?

Plain X-rays taken while weight-bearing will show the extent of the problem, helped by an extra view taken in the ‘schuss’ position. This shows wear at the back of the knee, which is often invisible when standing straight.

Usually, the combination of the story of the pain and how it began, the examination findings and the x-rays all add up together. We can then discuss with you, as you will usually be given a choice of which operation and when, and one option is always to soldier on for a while longer. When it is obvious that the knee isn’t getting better – you seldom have a good day any more and the knee swells and hurts during normal activities – then it’s time to consider surgery.

Which knee operation is right for me?

Sometimes, even with definite osteoarthritis in the knee, physiotherapy or a knee injection may suffice for a while, but if surgery is being considered, the choice will usually be between having a whole joint replacement or just having the part which is worn out relined – a partial replacement.

The attraction of the small operation is obvious; it’s a smaller operation, and by preserving the anterior cruciate ligament, the partial knee allows patients to return to a higher level of activity. The attraction of a total replacement is that it is ‘over and done with’. For some patients, the bigger total knee operation doesn’t allow a return to every activity, so it is a really important decision.

How do surgeons decide which knee operation is best?

Some surgeons have never been comfortable with the partial replacement approach and prefer the finality of the ‘total joint’, while others prefer the more conservative approach of a partial replacement. In the USA and many European countries, the partial approach is gaining popularity rapidly as the functional results are better, enabling patients to regain a higher level of activity. That higher level of activity is very important for some people but less important for others, when the choice of just one operation may be more sensible. We can discuss with you after your X-ray results, whether it would be sensible to be referred to a surgeon who also does partial knee replacements.

When should I consider a hip replacement?

There are many different causes of a painful hip, and it is not always osteoarthritis in your joint that is the issue. If you are beginning to get pain on a daily basis requiring you to take painkillers, or you are walking with a limp or waking at night, then please do come to see us for further investigation, as hip joint wear and tear is likely, and we will suggest referral to a specialist. X-rays are helpful in deciding where the pain is originating and whether degeneration in your joint has reached a stage that hip replacement would be sensible.

Hip replacements are generally easier to recover from than knee replacements. Patients are often up walking the same day, and hopefully home soon after, with much less pain than after a knee replacement and a much quicker recovery, so it is fine to consider surgery as soon as your hip pain is limiting the lifestyle you enjoy.

We will often refer you to a sports doctor or hip surgeon to have some imaging as soon as you develop hip pain, as physiotherapy and sometimes an injection can make a huge difference early on, and although you feel it in your groin, your pain may arise from your back.

Should I have a total hip replacement or a hip resurfacing?

For the painful, stiff hip, a hip replacement is a good option; the functional outcome after hip replacement is almost normal for everyday life. If you are male and life involved more exercise than walking the dog before the hip started to restrict you, then a resurfacing may be worth considering. It is the procedure that Sir Andy Murray had just 5 months before he won the men’s doubles tournament at Queens a few years ago.  The next generation of hip resurfacings, made of ceramic, not metal, is now available in the UK, and will be available to women too, which is an exciting development. Hip resurfacing has not been available for women recently, as they were found to have more complications of metal-on-metal erosion.

How long does it take to recover from hip surgery?

In terms of complication rates and speed of recovery, both procedures are now quick to recover from – most patients will walk the same day and leave the hospital after a couple of nights, or even one night if they hate hospitals. The anterior approach will enable a rather more rapid return to activity, but by six weeks or so, outcomes following the two approaches are indistinguishable.  To reach the top walking speed will take a few months, which is all that most people ever want. Running after resurfacing will take longer – your bones adapt to the operation, so it will slow you down until they feel ready. In the second 6 months after resurfacing, you will start to run, but not run at full speed, until around 12 months after surgery. Skiing or golf is fine after either operation, but all sports are easier after a hip resurfacing, as you have kept flexibility in your femur.

Is there an important difference between the anterior and posterior approaches to the hip?

Both ways of doing the procedure are tried and tested. The posterior approach is much more common in the UK, while in Europe and the USA it’s about 50:50, with the anterior approach now overtaking the posterior approach. The main difference is in the speed of recovery over the first few days – the anterior approach enables the hip replacement to be carried out through a ‘bikini crease incision’  without cutting any muscle, while even the most conservative posterior approach surgeon has to cut the muscles through a wound in the buttock that is visible in a bikini, should that be important to you. The posterior approach gives good access but does result in a slightly slower recovery in the first few weeks. An experienced surgeon using the posterior approach will produce a far better result than an inexperienced surgeon using the anterior or any other approach. I would ask your surgeon which approach they recommend and go along with it, as your GP will have selected them for you for a reason.

Are all hip replacements the same?

There are two major types of hip replacement: cemented or cementless. The attraction of bone cement is that it sets in ten minutes and is completely strong immediately. For the elderly who are less able to heal fast, this will make a substantial difference to the postoperative course, making it less painful and faster. For everyone else, a cementless hip seems a better option, with some large studies now showing that cementless hips are safe and reliable over 20 years later. In most of the developed world, over 90% of hips are cementless now with excellent results. Your surgeon will obtain better results using the device they are used to, so, as with the surgical approach, I would tend to take your surgeon’s advice, as your GP will have selected them for you for their expertise.

When should I see a specialist about knee or hip pain?

We are here to help you consider pain relief, injections, rehabilitation and surgery once your knee or hip becomes painful, whatever age you are so please don’t just put up with pain due to your reluctance to consider surgery. We are also able to ask you more about your symptoms so that we can assess how likely you are to have osteoarthritis and a knee or hip that will ultimately need replacing. We know the best sports doctors, the best physios, and many of the best knee and hip surgeons, so do make an appointment with one of us if you are in pain, even if just recently and only during certain activities.

To book an appointment, you can use the link here or call us on 0207 245 9333.