A thigh strain or quadriceps strain is a tear in one of the quadriceps muscles at the front of the thigh. It can range from a mild discomfort to a full blown tear of most of the muscle resulting in severe pain and inability to walk.
The breakage of the stitches starts within 2 weeks of the stitching but if you want the complete stitches to disappear then the process of hydrolysis or the enzymes in our body do that in a period of 60 days and therefore it approximately takes up to 2 months for the stitches to get dissolved.
1 Keep the area dry for the first 48 hours after stitches have been placed.  Then, you can start to gently wash around the site 1 to 2 times daily. Wash with cool water and soap. Clean as close to the stitches as you can. DO NOT wash or rub the stitches directly.