I could still run despite not being able to race, but my runs were shorter and my gait more lopsided as I tried to offload the weight from the inflamed hip and lessen the pain that would take longer to recede after each run.

Then the pain became permanent. Walking to the supermarket turned into a chore, and the pain would shoot down the leg at night, keeping me awake.

Resurfacing surgery was unavoidable if I wanted any semblance of a normal quality of life. But, if Andy Murray’s “Terminator” hip could carry him through five sets of tennis against the world’s best, could a similar hip let me run a few hours on trails and overtake some people?

In an operating theatre last May, Hong Kong surgeon Dr Jason Brockwell twisted my right hip out of its socket, then sliced it open.

A photo shows what looks like a shiny apple inside a thick steak. The steak was my glute muscle and the apple the ball of my femur. Brockwell filed down the “apple” and attached a metal cap to it. He also fitted a metal socket into my pelvis. Luckily, I slept through it all.

The recovery started from the moment I woke up. The nurse told me to walk. And I could, with the aid of a walking frame. I was delighted – racing felt closer than before the surgery, although that was probably drug-induced euphoria.

Brockwell cooled my enthusiasm, saying: “Distance running is the hardest sport to return to, even though it is not a complex action. A sport like tennis that involves short bursts of multidirectional activity is probably easier to return to than a unidirectional, long-period sport like running.”

Still, Brockwell had confidence in me – or at least the part of me that was his own handiwork: “The metal hip – that should run essentially forever, do millions and millions of cycles. The problem is not the artificial parts, it is the human parts.”

To race ultramarathons again, Brockwell explained, my human parts had to recover not only from the surgery itself, but also from the effects of the arthritis that preceded the operation. The muscles that move the hip back and forth had been tightened by years of running with a joint that did not have the full range of motion.

“In a resurfacing, the anatomy is returned to normal, as nature intended. The problem is correcting tightness and postural issues. If you cannot fully extend your hips, your gluteal muscles and hip extensors will not work properly,” he said.

I had to first rest the cut muscles, then stretch the chronically tight hip muscles, then strengthen them all, as well as regain the range of angles at which a normal hip operates. Then I could start to think about running.

Brockwell said the hip would need at least a year of rest and rehab before it could handle the training mileage required to race ultramarathons.

The first stage in recovery is the healing of the soft tissues cut by the surgeon’s knife. This takes about six weeks, and I spent them hobbling around on crutches. My only exercise for the first three weeks was lying on my back, moving my straight leg outwards. I felt like I aged 40 years – the body, reassembling itself after surgery, had no energy to spare.

The second six weeks is when the bone, fused with metal, regains its strength. One crutch was sufficient for short forays outside, and I started “flying solo” – crutchlessly shuffling about indoors.

The hip remained swollen, making the recovering leg longer than the good leg. The hip muscles lacked strength and I walked with a bizarre gait, dragging the weaker leg around in semicircles with my pelvis to one side, salsa-style.

I walked out of quarantine without crutches and with no salsa tilt.

After five months, I got the green light to try running (very slowly) on a running track. The Terminator hip was learning from scratch, and it was not the fastest of learners – it rushed the push off the ground, the leg wobbled through the air and the hip had no idea where to land the foot.

Frustrated, the hip sulked – it got tense, sore and refused to go any further than two laps.

It did not sulk for long. The second run, a few days later, felt easier. Soon the hip learned enough to run a full mile. Then another quarantine was due.

Almost seven months post-surgery, I spent my confinement loading a rotated hip – stepping up onto a chair with the leg set at different angles. I also started doing easy plyometrics, bouncing and jumping on one leg. (Sincere apologies to whoever was quarantined below).

Out of quarantine, feeling invincible (although slightly loopy – it was my fifth quarantine since the pandemic began), I went running. Not feeling any pain, I accelerated to a sub-three-hour marathon pace. The following day, I could barely walk.

“With all rehab, it is peaks and troughs. You must recognise the fact that you pushed things and you may need a rest period to recover,” my physiotherapist, Simon ten Cate Brouwer, told me.

I did not learn the lesson. Soon, I could run for 20, then 30 minutes. Eight months after surgery, I went on a rock-climbing trip.

I got tired of making excuses for not climbing hard, and on my last day I went for it. Two days later, I was climbing the stairs on all fours.

“After surgery, recovery is not time-dependent,” ten Cate Brouwer said. “Have you put in the effort, have you got enough strength and mobility to be doing these things? You have to earn the right to do every activity.”

I have not earned the right to climb yet. But, as the Terminator himself said: “I will be back.” And my first 10km (6.2 miles) run is planned for June, one year since the surgery.