What a joint replacement is
A joint replacement removes the worn surfaces of the joint and replaces them with an implant, so the joint moves on smooth artificial surfaces instead of bone on bone. It is resurfacing more than removal — most of your own bone stays.
Total hip replacement (THR): the worn ball at the top of the thigh bone is removed and replaced with a stem and a new ball; the socket in the pelvis is relined with a cup. The new ball glides in the new socket.
Total knee replacement (TKR): the worn ends of the thigh bone and shin bone are trimmed and capped with shaped metal components, with a smooth plastic insert between them. The kneecap surface is sometimes resurfaced as well.
What implants are made of
Implants combine a few well-proven materials: strong metal alloys (titanium or cobalt-chromium) for the structural parts, highly wear-resistant polyethylene (a dense plastic) for the bearing surface, and sometimes ceramic for the ball of a hip. Components are fixed either with bone cement or with coated surfaces your own bone grows into. Which combination suits you depends on your age, bone quality and anatomy — the choice is discussed at consultation, and it will be in your quotation by name.
How the surgery is done
The operation is performed under spinal and/or general anaesthetic and typically takes one to two hours.
For the hip, Dr Broadhead uses either the posterior approach (from the back of the hip) or the direct anterior approach (from the front, between muscles rather than through them). Each has advantages, and the honest summary is that both give excellent results in the long run; the anterior approach may make the first few weeks easier for some patients, though the evidence for a lasting difference is mixed. The approach recommended will be the one that suits your anatomy and circumstances, with the reasons explained.
For the knee, the focus is on accurate alignment and soft-tissue balance, with an enhanced recovery (ERAS) protocol so you are walking on the new knee within a day.
Robotic and custom approaches, plainly
You will see joint replacement marketed with words like robotic, computer-guided and custom. Here is what they actually mean:
- Robotic assistance does not mean a robot does the operation. It is a tool that helps the surgeon execute the pre-operative plan — the cuts and component positions — with high precision. Dr Broadhead has completed additional training in robotic-assisted knee replacement and uses it where it adds value.
- Custom planning means your implant sizes and positions are planned on detailed imaging of your own joint before the operation.
These tools improve precision. Whether that precision translates into better long-term results for most patients is still being studied — a fact stated plainly here rather than dressed up as a selling point. What matters most to your outcome is the decision-making, the planning and the execution, with or without a robot in the room.
How long a replacement lasts
Australia’s national registry has tracked virtually every joint replacement in the country for over twenty years, so this answer comes from data, not optimism. In its 2023 report, the registry found that at 20 years, the cumulative revision rate — the proportion of joints needing a re-operation for any reason — was 8.1% for conventional total hip replacements and 7.7% for total knee replacements performed for osteoarthritis.
Put the other way around: roughly nine out of ten replacements are still doing their job twenty years on.
The risks, honestly
Serious complications are uncommon, but they are real, and you should know them before you consent:
- Infection. The most feared complication. Superficial infections may settle with antibiotics; deep infection around the implant can require further surgery, occasionally including removal of the implant.
- Blood clots. Clots can form in the leg veins (DVT) and rarely travel to the lungs. You will have blood-thinning measures after surgery to reduce this risk.
- Dislocation (hip). The new ball can come out of the socket, most often in the early months. Rarely this needs revision surgery.
- Loosening and wear. Over years the implant can loosen and may need revision — this is what the registry numbers above measure.
- Fracture. The bone around the implant can crack during or after surgery.
- Nerve or blood vessel injury. Uncommon, and usually recovers, but can be permanent.
- Stiffness (knee). Some knees stay stiffer than expected despite good rehabilitation.
- Ongoing pain. Most patients get excellent pain relief; a small proportion — more often after knee than hip replacement — are left with some persistent discomfort.
Your personal risk profile — age, weight, other conditions — is part of the consent discussion. The surgeon’s job is to reduce every risk that can be reduced, and to be honest about the ones that cannot.