How long should it take for a deep bone bruise of the knee to heal?

Highly variable: Deep knee bruises (contusions) have a highly variable recovery timeframe. Not all bruises about the knee are the same. Important variables inlcude: actual location of bruise; level of impacting force applied to cause bruise; whether or not overlying articular cartilage is involved. Best diagnosed and followed by routine mri. Seek evaluation and treatment from your orthopaedic surgeon for your knee.