Initially they had decided on gout because of the location and the high uric acid levels in my blood. But i can't have the gout medication because all forms in all brands have dairy in the tablet filler. I also can't have non-steriodal anti inflammatory drugs either.... so I needed to try lowering my uric acid levels another way, hence the grapefruit juice. Fast forward several years and a bad fall in January 2021 leaving me with multiple stress fractures across both lower legs (at the knee joint) and in the left foot and I needed to see an orthopaedic specialist who diagnosed osteoarthritis in that particular joint that causes the pain. But what I do know and found out this January just gone is that if I miss a few days of grapefruit juice, that pain returns big time and will take around a month to settle again. My consultant tells me it is exceptionally unlikely to zero likelihood that I have both gout and OA in the same joint, so the answer is that it is arthritis (gout is a form of arthritis anyway), OA being my official diagnosis in that joint based on the x-ray. I just happen to have high uric acid levels in my blood as well which when I drink grapefruit juice each morning (200ml is the minimum needed from what I've read) is low enough that my doctor (GP) stops commenting on it at each blood test. So it's anyone's guess.
(Usually in Australia, they diagnose gout by giving you the medication and seeing if the problem goes away, along with blood tests. They don't MRI the joint or take fluid from the joint to analyse for the gout crystals. )