Changing MRI after subchondroplasty with partial meniscectomy for knee osteoarthritis.

A 54-year old woman with primary osteoarthritis and a tibial bone marrow lesion underwent subchondroplasty with injectable calcium phosphate. Post-operatively, the patient's symptoms worsened, and she lost the ability to bear weight. Follow-up MRI revealed previously absent, diffuse STIR hyperintensity in the tibia extending far beyond the surgical site. Twelve months post-operatively, symptoms spontaneously resolved. As the prevalence of subchondroplasty grows it will be important to recognize potential complications. To the authors' best knowledge this is the first report of significantly worsening pain and difficulty bearing weight corresponding with diffuse hyperintense T2 signal in the tibia after a calcium phosphate subchondroplasty.