Author: Arsh Singh Dhanota, MD
Co Author #1: Thad Woodward, M.D. (Clinical Faculty, Family & Sports Medicine, Kaiser Woodland Hills Family Medicine Residency Program)
Co Author #2: Arik Lainer, M.D. (Consultant, Interventional Radiology, Department of Radiology, Kaiser Foundation Hospital, Woodland Hills, California)

Patient Presentation:
A 16 year old male with a 3 week history of left medial thigh pain.

History:
The Karate Kid is a 16 year old male martial artist who presents with a three week history of intermittent left medial thigh pain that's 8/10 in intensity and throbbing in nature. The pain is worse with weight-bearing and impact activities such as hiking and karate, and minimally improves with rest. He was evaluated by his Pediatrician 10 days ago, diagnosed with a left quadriceps tear and was restricted from impact activities, given Ibuprofen, and referred to Sports Medicine for consultation. He has also been stretching his left quadriceps musculature for the last ten days. These interventions have provided minimal relief. He reports no recent history of trauma although he has taken repetitive impacts to his thighs over the last five years as a martial artist. In addition he reports a palpable knot in the affected area. His pain has progressively worsened and is now restricting his ability to perform his activities of daily living such as walking up and down the stairs. His Pediatrician ordered an x-ray of his left femur which was read as normal. Review of systems is otherwise negative.

Physical Exam:
Left Lower Extremity:
Inspection: Symmetric quadriceps musculature bilaterally.
Palpation: tenderness to palpation of the left vastus medialis muscle with a palpable 2 cm mass deep to the vastus medialis muscle.
Range of motion: He can passively and actively flex and extend his left knee and hip with full range of motion. He's able to passively and actively abduct and adduct his left hip with full range of motion
Strength: 5/5 strength when testing his quadriceps musculature however flexion of his left leg and extension of his left knee illicits pain. 5/5 strength for hip adduction and abduction.
Gait: antalgic, favoring his right leg.

Click here to continue. Challenge yourself by writing down a broad differential diagnosis before moving to the next slide.