If you see Nigel Foster striding purposefully across the South Downs near his home town of Petersfield in East Hampshire, he’s there for a very good, if rather unlikely, reason. He is truffle hunting.

The 66-year-old former marine pilot can be seen most days on the trail of his faithful Italian waterdog called Otto, as the relentless hound snuffles out the treasured black fungus from the rich southern English earth.

But just a few short months ago, Nigel would have been wholly incapable of indulging in his unusual pastime, as he was beset by arthritis, cartilage loss and grinding bone-on-bone pain in his right knee making walking more and more difficult.

Now, after undergoing private surgery in a top French hospital organised by a new UK-based company Elite Surgery Abroad (ESA), the active ex-seafarer is back on his feet, walking his dog, working with a personal trainer and even contemplating skiing again.

“The difference is quite remarkable,” he said, shortly after coming into his house after another outing with Otto. “I was becoming miserable with the constant pain. Every step was agony and, even when I was not walking, it nagged and nagged, like toothache. I was even starting to limp.”

The ex-pilot – a master mariner who guided ships, including passenger liners, container ships, car transporters and ore carriers, through the flotillas of yachts and surging tides of the Solent – first became aware that all was not right with his knee three years ago.

He said: “It started to hurt when I walked. Every step caused a twinge. I was sent by my doctor to see physiotherapists, and X-rays confirmed the arthritis damage. A year went by and I must have seen eight different physios, who gave me exercises which made no difference.

“Then a senior physio referred me to be fast-tracked by NHS Southampton’s PlusPractice private wing, and it looked as if I would be offered an operation within months. But medical checks saw that I have sleep apnea – where my breathing stops and starts.

“They immediately said I could not be treated, because they did not have the relevant resuscitation capability, so I was referred back to my own hospital in Portsmouth and returned to the NHS waiting list.”

After seeing a social media advert for Elite Surgery Abroad, which is pioneering transformative surgeries in Amiens, northern France, and is dispatching rapidly-increasing numbers of patients from the UK for first-class treatment at an affordable price.

He said: “ESA were lovely and helpful from the beginning. Obviously, I had some reservations, as I am a relatively cautious person, but I did my research. My brother-in-law, who speaks fluent French, looked at French sites and could only find positive things about the Victor Pauchet Clinic, where the operation was to be carried out.

“What swung it for me was the comprehensive nature of the package, which included fantastic aftercare and allowed my wife, Toni, to accompany me. ESA even booked me as a precaution into an intensive care unit, because of my sleep apnea, at no extra cost. The hospital also has a whole cardiology department.

“The whole experience was superb. It was so calm and tranquil. My Portsmouth hospital is always bustling, and everyone is busy. At the Amiens clinic, if you pushed the buzzer in the private room, a nurse was there in seconds, offering painkillers, or other help.

“Although I don’t speak French, the language was not a problem. All the senior medical staff spoke English and besides ESA provides a translator/guide for all your pre op appointments, and during your stay in hospital.”

Nigel said the immediate post-op period was painful, but he was offered physio right away, and it continued in the Novage residence where he and Toni stayed for 11 days afterwards, again receiving daily nursing care and private exercise classes.

He paid £11,000 for the whole 18-day package, which included transport to and from the hospital and all meals, compared to the £16,000-minimum estimate he was given by a private chain in England. He also had the services of a private GP with ESA when he returned to the UK.

ESA was founded by Frenchman Raoul Mkoh, who previously was financial controller with the Pauchet Santé hospital group, and is now living and working in Scotland.

With waiting times for NHS orthopaedic surgery in the UK remaining high, roughly half of hip and knee replacements are carried out privately, according to the Nuffield Trust.