AFAIK the enzymes only act upon collagen in scar tissue, not normal collagen in joints. If anything, there is some tentative evidence to suggest Bromelain potentially could be used to reduce the effects of some forms of osteoarthritis due to it being an anti-inflammatory.

From that study:

Bromelain has been used as treatment for a number of disease conditions, in addition to osteoarthritis of the knee and shoulder joints (Table 1). No serious adverse events have been reported with the consumption of either bromelain or pineapples in these studies. Adverse events that have been reported are mainly gastrointestinal (i.e. diarrhoea, nausea and flatulence), but have also included headache, tiredness, dry mouth, skin rash and allergic reactions (not specified).

Should be noted, however, that there was a conflict of interest announced at the end:

Dick Middleton is consultant to Lichtwer Pharma UK Ltd who manufacture bromelain. Steven Hicks was funded by Lichtwer for a post-graduate fellowship from 1998 to 2002.

Still, the research seems to indicate that as long as the daily dose is 600mg or lower per day, it should be well tolerated as long as you’re not allergic to pineapple. Even above that, there should be no long-term negative health effects, only potentially acute side effects.