There is nothing really over the counter that is safe for bunnies. Glucosamine is safe for bunnies but those type of supplements only work for joint pain by producing more joint fluid which helps cushion the joint and prevent bone on bone action which is painful. With excess fluid already on the joint I am not sure if it would be recommended at this point- maybe down the road.
I had a foster dog that tore a ligament in his knee and he needed surgery on the knee- and his knee is thicker and did build up some scar tissue as a result of the injury and surgery. There are a lot of things that can go wrong with a knee- torn ligaments, breaks in the bone or even kneecaps that don’t stay in place (luxating patella).
SInce he is “bunny hopping” and keeping both legs together that might be a good thing to help protect the other knee. Once one knee is injured it is common in dogs for the other knee to eventually “go” also- from the stress and strain on the good leg during recovery and if the animal continues to favor the “bad” leg that just adds and adds to the “good” leg.
One thing that will be very important no matter what the cause of the injury- is to keep Sugars weight at normal- do not allow him to become overweight as that will add more stress on the joints. And it is possible he might not be as active as another bunny- so keep that in mind with any general bunny diet recommendations. It would be better to have him on the trim side as opposed to the chubby side.
Are there any vet colleges around that see animals? Once you get into a specialized problem that is not specific to rabbits other specialists should be qualified to see a bunny then. For example- if your rabbit had a heart condition and needed some testing- you would most likely see a cardiologist than a general rabbit vet- and they would consult together to determine best course of treatment.
The musculoskeletal system is going to be similiar with bunnies, dogs, cats- so a orthopedic vet should be able to diagnosis an issue- that vet might need to consult with an exotics vet if the bunny needs to be sedated if they do not do it routinely- but most vets work readily with vets that specialize.
So maybe a vet college or large city might have different options? And it may not be necessary to always return to the specialist for care- the regular exotics vet could manage a pain treatment plan if that what was needed, etc….
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