I’ve been having a rather annoying debate with my 77-year-old mother in the UK about her X-ray showing “severe” osteoarthritis of the right knee.

It’s been there a fair while, and perhaps one could generously say it moderately affects her life.

I’m suspicious as to how much the knee itself is to blame. Sure, she does struggle on rising from a sitting position, and launches herself backwards into the seat when sitting down.

But she has become a little rotund as the years have gone on, her legs were never the strongest, and she’s almost 80.