Doc, my knees give way!

A 50 year old obese man presented to the emergency department with pain in both knees. A week before presentation, he had experienced a sudden acute pain in his left knee while walking in his kitchen. He was not able to bear weight on the affected leg, so he attended the accident and emergency department. He was discharged without a definite diagnosis. When he returned home, he struggled to walk. His right knee suddenly gave way painfully as he pivoted himself to turn. He reported not having any pain in the knees before these incidents. The patient had no significant medical history. On examination, there was swelling in the suprapatellar region of both knees, with bruising on the left side. He was unable to perform straight leg raise and active extension of either of his knees. Both the knees could be fully extended passively. Active and passive flexion of the knees was limited by pain. Hip examination did not reveal any abnormalities. Knee radiographs were performed.⇓ ⇓ Fig 1  Lateral view radiograph of the patient’s left knee Fig 2  Lateral view radiograph of the patient’s right knee ### 1 What are the radiographic findings? #### Short answer The two lateral view radiographs show soft tissue swelling, disruption at the quadriceps tendon, and suprapatellar calcific density.⇓ ⇓ The patellae are low lying. Fig 3  Lateral view radiograph of the patient’s left knee showing suprapatellar swelling, quadriceps disruption, and suprapatellar calcification …