O'Donoghue's unhappy triad

Case contributed by Dr Mohammad A. ElBeialy


Knee pain, swelling and giving away for 3 months since trauma.

Patient Data

Age: 30 years
Gender: Male

Bucket-handle tear of the posterior horn of medial meniscus with double PCL sign and increased intra-meniscal signal seen disrupting both articular surfaces and menisco-capsular attachment. Full thickness tear of the ACL with indistinct outline and increased signal intensity. The medial collateral ligament shows mild thickening with increased signal intensity within and around. Moderate joint effusion. The posterior lateral tibial condyle shows patchy area of marrow edema signal demonstrating low T1 and bright PD FS and STIR signal.The popliteus muscle shows edema signal with high T2, PDFS and STIR signal.

Case Discussion

O'Donoghue's unhappy triad results from valgus stress with rotation of the knee. It comprises ACL tear and MCL injury (tear or sprain) with a medial meniscal tear.

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Case information

rID: 21809
Published: 19th Feb 2013
Last edited: 22nd Nov 2020
Inclusion in quiz mode: Included