Smith & Nephew and Cori...

It proved just the ticket. Less than a week after the operation, Foulk was running five kilometres on the treadmill, and these days he thinks nothing of competing in marathons, ironman triathlon events and so-called "ultra-marathons".

"I've put the device through its paces and I've had no trouble at all," he said.

Hundreds of thousands of Americans will soon benefit from the same medical advances. Since Foulk underwent his operation, the new generation of implants - in which the surfaces of the bones in the hip are replaced with metal - has been licensed for use in America. What is surprising is that the only two firms offering this innovation in the US are British.

Smith & Nephew and its smaller, Cirencester-based rival, Corin, which has its own version, are going head to head to persuade surgeons to switch to the new technique. Because it is suitable for younger patients, both companies hope to be able to expand the overall $2 billion (£1 billion) market for artificial hips rather than simply tap into existing demand.

Although the new devices have become commonplace in Britain, Europe and Australia, they have only recently arrived in America, a key market.

The new metal-on-metal joints are significantly better than their predecessors, largely because they last much longer, which is why they are more suitable for younger or more active patients.

The new procedure involves putting a metal cap at the top of the femur and inserting this into a metal cup in the pelvic bone. This type of joint is an improvement on the older-style devices that use polythene. These wear less well and are more prone to dislocation.

The pioneer behind the technology is Derek McMinn, a consultant orthopaedic surgeon, who started developing hip resurfacing at Corin before leaving to set up his own company, MMT, later acquired by Smith & Nephew.

Despite getting the technology later than its rival, Smith & Nephew brought the product to America 14 months before Corin, launching its Birmingham Hip Resurfacing (BHR) device in May 2006.

Corin, which has signed up Stryker, a big American medical-devices manufacturer, as its distribution partner, began marketing its Cormet implant last July.

The manufacturers are locked in a fierce battle to train surgeons in the procedure and gain market share before domestic rivals develop their own versions.

Joseph DeVivo, head of Smith & Nephew's orthopaedics division, thinks being the first into America has given it a strong advantage. "It's always important to be first," he said. "It's paying off handsomely." The figures back up his claim. According to S&N's annual results, published last month, "reconstruction revenues" in America grew 13%, boosted by BHR sales.

Simon Hartley, finance director of Corin, sees it differently. "The first one into a market spends a lot of time educating people. Often it's not a bad thing to be second."

For now, the aim of both companies is to convert American surgeons to the view that resurfacing devices are the way forward.

Hartley said: "This industry is dominated by the big players and they sell a lot of hip replacements in the US. Traditionally, they have put them into older patients.

"Resurfacing was a little off the wall when it was first envisaged and there has been a lot of scepticism among the big boys, who are waiting to see whether it takes off."

Both groups expect the competition to become more intense. DeVivo said: "We have always expected we will have to exist in a competitive market. We've been competing internationally [on hip replacements] for the last seven to ten years and been able to maintain our leadership."

Zimmer, Biomet, Johnson & Johnson and Wright Medical are all developing their own next-generation hip implants. Michael Mitchell, an analyst at Oriel Securities, said: "There is space, not just for one or two players, but for four, five or six." So Corin and Smith & Nephew temporarily have a window of opportunity.

Not everyone is convinced that resurfacing is going to take America by storm. A survey of surgeons published recently by analysts at Goldman Sachs, the investment bank, found that the majority of respondents felt the new devices would see "only modest uptake", accounting for 3%-5% of all hip replacements in 2010.

Others are more optimistic. Nomura Code, the stockbroker, thinks 10% of all procedures will use resurfacing devices by the same date. Hartley, for one, is realistic. "One issue is price – resurfacing devices are more expensive. It will take time for surgeons who are comfortable with regular devices to move over."

This business is definitely a marathon, not a sprint.