Joint resurfacing

Joint resurfacing is a type of surgery for arthritis that caps or repairs the worn surface of a joint, rather than replacing the whole thing. It's most often carried out on the hip or knee, and because it keeps more of your own bone in place, it can mean a faster recovery than a full joint replacement.

What conditions does it treat?

Joint resurfacing is used to treat arthritis, most often osteoarthritis, when it's causing severe symptoms that haven't improved with non-surgical care such as activity changes, physiotherapy or medication. In osteoarthritis, the smooth cartilage lining the joint becomes flaky and cracked, the bone underneath thickens, and the joint lining becomes inflamed, eventually leading to bone rubbing directly on bone.

• Persistent joint pain
• Stiffness or a reduced range of movement
• Swelling
• A feeling of instability in the joint
• Difficulty walking or moving normally

Hip resurfacing tends to suit younger, active patients with strong, healthy bones. Knee resurfacing suits people with early, localised wear in just one part of the knee, who often have a higher activity level than those needing a full knee replacement.

What are the benefits of joint resurfacing?

• Less joint pain and improved function
• A faster return to normal activities than a full joint replacement, since the procedure is less invasive
• For the hip: a lower risk of dislocation, since the resurfaced head keeps its natural size and sits securely in the socket, and a better chance of returning to sport, including competitive sport
• For the hip: well-selected patients have reported failure rates of around 0.5% to 2% at 10 years
• For the knee: recovery is reported to be around three times faster than standard knee replacement, and results over the last 20 years suggest at least 15 to 20 years of function
• If a resurfacing does eventually wear out, revision surgery is often more straightforward than revising a full joint replacement, because more of your own bone has been preserved

Are there different types of joint resurfacing?

Hip resurfacing

• Metal-on-metal resurfacing, such as the Birmingham Hip Resurfacing (BHR) system, first used in 1997 and now with over 190,000 implantations worldwide; this type is generally reserved for male patients with a hip socket larger than 50mm, as results are less predictable in women and smaller patients
• Ceramic resurfacing, a newer alternative that avoids some of the concerns around long-term exposure to metal wear particles

Knee resurfacing

• Medial (inner) resurfacing, the most common type, since around 80% of knee arthritis starts on the inner side of the joint
• Lateral (outer) resurfacing, for the smaller number of patients whose wear begins on the outer side
• Patellofemoral resurfacing, which resurfaces only the underside of the kneecap and the front of the thigh bone, leaving the rest of the knee untouched
• Multi-compartmental resurfacing, a newer, more specialised option that resurfaces two of these three areas at once while preserving the knee's natural ligaments

What happens before the operation?

You'll discuss the details of your surgery with your team, including the type of anaesthetic you'll have, and go through checks to make sure you're fit for the operation. These commonly include:

• Blood tests and a heart tracing (ECG)
• A dental check, to reduce the risk of infection after surgery
• Imaging such as X-rays, and sometimes an MRI or CT scan
• A review of your regular medications and supplements, some of which may need to be paused beforehand

In the weeks before surgery, it helps to stop smoking, eat a healthy, nutrient-rich diet, keep up any conditioning exercises you've been given, and lose weight if you've been advised to. Avoid alcohol for 48 hours before your operation. You'll be told exactly when to stop eating and drinking beforehand, usually around 8 hours, and which medications, if any, you can take with a small sip of water on the morning of surgery.

What happens during the procedure?

Hip resurfacing

1. You're given a general anaesthetic, or a regional anaesthetic that numbs the area around your hip.
2. Your surgeon makes a cut around the side of your hip and buttock, then removes the damaged cartilage and bone from your hip socket.
3. A metal shell is fitted securely into the socket.
4. The head of your thigh bone is reshaped and trimmed, then covered with a metal or ceramic cap.
5. Your surgeon fits the resurfaced head back into the new socket and realigns your hip. Reported operating times vary from around 1 hour to 2 to 3 hours, so check with your own team what to expect.

Knee resurfacing

1. You're given a general or spinal anaesthetic.
2. Your surgeon makes a cut, usually around 4 inches long, over the affected side of your knee, avoiding your ligaments and kneecap.
3. The worn bone surface, whether on the inner side, outer side, or underside of the kneecap, is relined with a thin metal surface.
4. A small plastic bearing is fitted on top, so the joint glides smoothly rather than grinding.
5. Local anaesthetic is infused into the knee to help control pain as you wake up. The operation usually takes around 1.5 hours.

What does recovery look like?

In hospital

You're moved to a recovery area while the anaesthetic wears off, with your pain, pulse and blood pressure checked regularly, and an X-ray is taken to confirm the new joint surface is well positioned. A physiotherapist gets you moving quickly, often from the day of surgery, helping you stand, walk with crutches or a frame, and, for a knee, start bending the joint. Hospitals vary in their approach: some treat this as a day case with discharge the same day, others plan for a night or more before you're ready to go home.

At home

After hip resurfacing, expect to use crutches for up to 6 weeks, with a wound check at around 2 weeks and a clinic review at 6 weeks. You'll usually be advised not to drive, bathe (showers are fine) or have sex for 6 weeks, and to build up to low-impact sports such as golf, swimming or cycling from about 3 months, with high-impact sports such as running or football not generally recommended. Returning to work typically takes 6 to 12 weeks, depending on how physical your job is.

After knee resurfacing, outpatient physiotherapy usually continues from around 2 weeks, with follow-up appointments at roughly 8 weeks and again at 6 months, when an X-ray checks the implant has bonded well. Dressings typically stay in place for about 10 days, and recovery is generally reported as notably quicker than after a full knee replacement, with many people back to activities such as swimming, dancing and gym work within a few months.

Whichever joint is involved, contact your care team promptly if you notice increasing pain, redness or swelling, fluid leaking from the wound, an unpleasant smell, or a high temperature.

What are the risks and complications?

As with any major joint surgery, there are some general risks to be aware of.

• Blood clots in the leg or lungs, which is why you'll be encouraged to move early and may be given blood-thinning injections
• Infection, ranging from a minor wound infection to a deeper infection of the joint, which occasionally needs further surgery
• Bruising and swelling around the joint, which is normal and settles over the following weeks
• Rare but serious complications such as heart attack, stroke or death, in line with any major operation

Some risks are specific to the joint involved.

• Hip: gradual wear or loosening of the implant over time, which may eventually need revision surgery
• Hip: with metal-on-metal implants, a small number of patients develop metallosis, where tiny metal particles irritate the surrounding tissue; this is treated by replacing the metal bearing
• Hip: temporary numbness over the outer hip, or rarely nerve damage, which can take up to 12 months to settle
• Knee: some difficulty fully bending the knee afterwards, particularly if arthritis was advanced before surgery
• Knee: infection affecting the joint, reported in under 1% of cases in one surgeon's own practice, though it may require removing and later replacing the implant