Repaired Medial Meniscus

Hi all,
I am 37 years of age and had a left knee medial meniscus repair done about 11 weeks ago. Am currently walking with the aid of one crutch. I've been doing some simple physical exercise at home in order to strengthen my quadriceps and hamstring.
About four days ago I tried working out on a stationery bicycle. I did this for two consecutive days without any discomfort but on the third day i had a very sore knee so I avoided the excercise.
Does feeling sore mean that the flesh on the knee joint has'nt healed completely and is working out on the stationery bike safe?