Hi,having had 2 athroscopys myself on my left knee,the last one i had was Feb 2008,and had a lateral mynesectomy,i have a bucket handle tear,and 50% acl tear,but existing fibres was told were quite strong.im 43 male too,went back to playing football but only veterans.
Everything fine until last month,then same as you pain appeared in medial side under knee cap,sharp pain when fully extend leg with weight on it,im not sure wether its because i have been nursing leg along and muscle wastage,so been on bike at gym to build,but still sharp pain!
i was able to one legged squats on bad leg before,but does not feel strong enough to do now,and just on last bit of straightening the sharp pain!
Physio baffled,doesnt think i have torn meniscus further,going back next week.
thought i would drop you a line as seem very similar.