Changes of osteoarthritis are more marked in the lateral compartment with there is very little normal remaining articular cartilage but are also present in the medial and patellofemoral compartments.
A pattern of bone marrow oedema in the tibial plateau particularly medially is associated with a horizontal fracture line consistent with an insufficiency fracture.
There is very little remaining lateral meniscus. Complex degenerative tear of the posterior horn and body of the medial meniscus.
The ACL and PCL are within normal limits. Collateral ligaments are unremarkable.
There is a small Baker's cyst emerging between the semimembranosus tendon and the medial head of the gastrocnemius. Mild tendinopathy of the popliteus tendon.Quadriceps tendon, patella, and patellar tendon are unremarkable.
Small joint effusion.
Conclusion: Tricompartmental osteoarthritis, worse on the lateral compartment. Insufficiency fracture right-sided tibial plateau.