This is not typically normal with mild-moderate activity, six months post surgery; though increased amount of activities are best avoided. I would suggest getting this examined by your treating orthopedician for secondary issues such as inflammations, further degeneration, bursitis, tendonitis etc. If a secondary issues is identified it can be managed accordingly. Meanwhile I would suggest resting the knee and avoiding aggressive movements around the joint. Ice packs and OTC NSAIDS may be helpful for pain relief.
Hope this is helpful.
Thank your for the feedback. Originally, the doctor diagnosed is as pes bursa inflammation as a result of its response to ice, ultrasound and rest therapy. I requested an MRI which revealed a stress fracture in the general area where the screws for the ACl reconstruction were placed. We are following up with a bone density test to rule out osteoperosis. What other reasons could cause the stress fracture with such a moderate increase in activity?