The short answer before the detail-I do not do it.
If you are weighing these two operations today, the decision is made for you if I am your surgeon. Resurfacing caps your own femoral head instead of removing it, which suited a narrow group — young, large-framed, active men who wanted to keep their bone.
But it runs metal on metal, and that bearing harmed some patients and failed early especially in women and in smaller frames. And the long-term results are poor compared to a total hip replacement. The incision is also longer compared to a regular hip replacement. This page explains the reasoning behind why I do not perform this surgery.
What is actually different about the two operations
In a total hip replacement the head and neck of the femur are removed and a stem is placed down the inside of the femur with a new ball on top. The socket is reamed and a shell with a plastic liner is fixed into it.
In a resurfacing the head of the femur stays. It is trimmed and a metal cap is cemented over it, with a short peg running down into the neck. The socket takes a thin metal shell. The ball then runs metal on metal, because keeping the patient’s own head leaves no room for a plastic liner.
That last sentence is the whole story. The bearing is not metal on metal because anybody preferred it. It is metal on metal because the design leaves no room for anything else.
A film showing a resurfacing on one side, where the head of the femur is capped rather than removed, alongside a conventional replacement with a stem. Look at how much more of the femur is retained on the resurfaced side. That difference is the entire argument for the operation.
The genuine case for keeping your own femoral head
Bone preserved. If a resurfacing fails, converting it to a standard total hip replacement is comparatively straightforward because the femur has not been touched. For somebody in their thirties or forties who is certain to need more than one operation in their life, that is one argument. But it is wrong in my onion because standard modern total hip replacements last a long time.
A very large head, which is inherently stable and difficult to dislocate.
And in published series from surgeons who perform a great many functions in young active men has been reported as excellent, including return to demanding activity.
Even in the best hands, the results are not as good as compared to the standard hip replacement in my opinion.
Why I do not offer it
Five main reasons.
The bearing. Metal running against metal releases particles. In some patients that produces a local reaction destroying muscle and bone around the joint before it produces much pain, which is the dangerous part, because by the time it declares itself the damage is done. I have no way of predicting in advance which patient will react that way. It is also unsuitable for a woman who may become pregnant, because those ions cross the placenta.
The registry data. Failure rates in women, and in anybody needing a smaller femoral component, were high enough that the manufacturer withdrew the smaller sizes and issued warnings for those groups. When a manufacturer withdraws its own sizes, I treat that as a strong signal.
The technique is unforgiving. Notching the neck of the femur while preparing it, or seating the cap in the wrong position, produces failures a total hip replacement would not have had. It is a volume-dependent operation and I am not going to perform a handful a year of an operation like that.
The incision is also longer compared to a regular hip replacement because the entire head of the joint has to be dislocated to be replaced.
And the alternative improved. A modern total hip replacement in a young patient, with a highly cross-linked polyethylene liner and a ceramic head, wears at a rate that has changed what can be offered.
Much of the original argument for resurfacing was built against the plastics of the nineteen-nineties, and those are not what I am implanting.
Side by side
| Hip resurfacing | Total hip replacement | |
|---|---|---|
| Femoral head | Kept and capped | Removed and replaced by a stem and ball |
| Bearing surfaces | Metal on metal | Ceramic on highly cross-linked polyethylene in my practice |
| Metal debris concerns | A recognised and specific problem | Not a feature of this bearing |
| Suitable in a woman who may become pregnant | No, because metal ions cross the placenta | Yes |
| Typical candidate | Young, active, usually male, larger frame, good bone | A very wide range including the above |
| Women and smaller sizes | Higher failure in registries; smaller components withdrawn 2015 | No such pattern |
| If it fails | Usually convertible to a standard replacement | Revision, which is a larger undertaking |
| Follow-up needed | Blood metal levels and cross-sectional imaging in some patients | Ordinary follow-up |
| Do I offer it | No | Yes |
If you already have a resurfacing
Do not panic and do not assume it has to come out. A great many are working well many years later.
What I would want is that somebody is actually following it: periodic X-rays, blood tests for cobalt and chromium levels, and cross-sectional imaging designed to assess the soft tissues if the levels are raised or there are symptoms.
What should bring you in sooner: new groin pain, a mass or swelling around the hip, a new limp, or clunking that was not there before. Those make me look for a reaction to metal debris rather than assume ordinary wear.
If you received one of the sizes later withdrawn, that is a reason for careful follow-up. It is not on its own a reason for surgery.
Who I still send elsewhere
Anyone insisting on a hip resurfacing. Sending a patient away for an operation I do not perform costs me nothing and it is the right thing to do.
What I implant instead
These are films from my own patients, each of whom I treated with a total hip replacement rather than a resurfacing. They show the conditions that brought them to me — avascular necrosis, arthritis, and developmental dysplasia — rather than the young resurfacing candidate discussed above. Resurfacing is not possible in patients below.
An anteroposterior X-ray of the pelvis before surgery, showing avascular necrosis of the left femoral head.
An X-ray of the pelvis before surgery, showing arthritis of the right hip.
An X-ray of the left hip before surgery, showing developmental dysplasia of the hip.
An axial T1-weighted MRI of both femoral heads before surgery, showing avascular necrosis.
A coronal MRI before surgery, showing avascular necrosis of the left hip with collapse of the femoral head.
My financial position on this operation
I have no financial relationship with the manufacturer of any resurfacing system or any hip implant. I gain nothing from declining this operation and nothing from recommending the alternative.
Which risk I would rather carry
Where I differ from some surgeons is in which kind of risk I would rather carry, and I think that is the honest way to frame this rather than pretending one option is simply better.
A bearing whose failure mode is wear I can measure on a film is a different proposition from a bearing whose failure mode is a soft tissue reaction that can be well advanced before it causes pain. I would rather have the first, and I would accept a slightly larger operation to get it.
That is a judgement, and somebody could weigh it differently without being wrong. What I will not do is perform a handful a year of an operation that is unforgiving and volume-dependent.
Common questions
Which is better, hip resurfacing or a total hip replacement?
For everyone I see, a total hip replacement. Resurfacing runs metal on metal, which harms the tissue around the joint in some patients. A modern replacement runs a ceramic ball on a plastic liner, whose wear I can measure on an X-ray.
Can a woman have hip resurfacing?
I would not advise it. The metal-on-metal bearing releases cobalt and chromium ions that cross the placenta, and registry data showed higher failure in women and in anyone needing a smaller component — enough that the maker withdrew the smaller sizes in 2015.
What is the actual difference between the two operations?
In a resurfacing your femoral head is kept and capped with metal, and the ball runs metal on metal. In a total hip replacement the head and neck are removed, a stem is fixed inside the femur, and a new ceramic ball runs on a plastic-lined socket. Resurfacing keeps more of your own bone; that is its whole argument.
I already have resurfacing. Does it need to come out?
Not necessarily, and do not panic. Many are working well many years later. What matters is that someone is following it with periodic X-rays and blood tests for cobalt and chromium, and imaging of the soft tissues if the levels rise or symptoms appear. New groin pain, a mass or swelling, a new limp, or new clunking should bring you in sooner.
