Skip to content





Musculoskeletal system

Pediatric musculoskeletal conditions
Musculoskeletal injuries and trauma
Bone disorders
Joint disorders
Muscular disorders
Neuromuscular junction disorders
Other autoimmune disorders
Musculoskeletal system pathology review



0 / 15 complete


1 / 7 complete
High Yield Notes
7 pages


15 flashcards

USMLE® Step 1 style questions USMLE

6 questions

USMLE® Step 2 style questions USMLE

6 questions

A 15-year-old boy comes to his general practitioner because of generalized right knee pain that has gradually worsened over the past five months. He does not recall any trauma or any inciting event. He says that the pain is accompanied by catching and clicking of the joint and is worsened by physical activity. He works on a farm and enjoys playing soccer with his siblings but has been unable to do so for the past month due to his symptoms. His knee appears swollen and is tender on palpation medial to the patella. Range of motion is limited and the knee clicks as it extends. The McMurray test is negative. Imaging cannot be obtained because the patient is unable to travel to an imaging center. Which of the following is the most likely diagnosis?

External References

Content Reviewers:

Rishi Desai, MD, MPH


Tanner Marshall, MS

Osteo- means “bone”, and -arth- refers to “arthron” which means joint, and -itis means “inflammation”, so osteoarthritis is a disease involving inflammation of the bone and joint cartilage.

It was once thought that the “itis” part of osteoarthritis was a misnomer, and that inflammation didn’t play a role in its development, and that it was mostly a degenerative disease resulting from simple “wear and tear”.

Nowadays, it’s thought that inflammation does indeed play an important role in the development of osteoarthritis.

Alright, so a healthy joint consists of two bones, each with its own layer of articular cartilage, which is a type of connective tissue that allows the two bones to glide against each other essentially without friction.