urgent help required for 3rd declension adjective HELP!!!!!

[medicine boi]

i require urgent assistance on the following questons put together without chnaging the word order

questions
fracturae costae fluctuans-(to me this sentences is gramatically incorrect i dont know how the hell to change it)
propter complicationes recens post operatio difficilis-My answer Propter complicationem recenem post operationem difficlem
the correct answer propter complicationes recenes post operationem difficlem wtf how on earth can complicatio be declined to its nom pl form? when it praceeds an accusative preposition? like wise with recens why is it not declined to recenem????
contusio musculus teres et musculus triceps humerus- no idea about this answer
ex spatia intercostalis -ex spati intercostale took a wild guess the correct answer is ex spatis intercostalibus again i'm lost fowards At the BS i havent slept for 2 nites streight because of this i have a fourth comming exam in a few days and this is killing me

[modus.irrealis]

I don't quite get what you're supposed to do with those questions, but...

the correct answer propter complicationes recenes post operationem difficlem wtf how on earth can complicatio be declined to its nom pl form? when it praceeds an accusative preposition? like wise with recens why is it not declined to recenem????

The -es ending is used both the nominative and accusative plural, so post complicationes recentes is grammatical.

ex spatia intercostalis -ex spati intercostale took a wild guess the correct answer is ex spatis intercostalibus

I think here, spatia is to tell you to use the plural ablative instead of the singular. (Also note that it's spatium so the ablative singular would be spatio.)

About the rest, it's tough without knowing what you're supposed to do... like with the first one, you could have fracturae costae fluctuantes/fluctuantis/fluctuanti which would all be grammatically correct (although not complete sentences) depending on the case and number of costae.

For the other one, there's all sorts of ways you could change the case of words to get grammatical Latin, e.g. contusio musculi teretis et musculi tricipis humeri, but how do you know which one is the one that's intended?