Type III PCL avulsion and lipohemarthrosis of the knee

Case contributed by Dr Ali Abougazia


Severe trauma to the knee during a football match.

Patient Data

Age: 16
Gender: Male


It's easy to see the PCL tear from its tibial attachment in this case. However, noticing the layering in the effusion which signifies lipohaemoarthrosis is of paramount importance, because it means that there's an overlooked intra-articular fracture. The fracture in this case is actually an avulsed segment from the tibia at the PCL insertion, type III. Look again and you'll find the small low signal cortical portion attached to the PCL. Easy to miss, huh?

Also, never forget evaluating the peri-articular musculature. In this case, you'll find a heterogenous high T2 signal in the popliteus muscle, it was contused during the trauma. However its tendon remains intact, so it's not torn.

Case Discussion

The findings compatible with type III PCL avulsion with lipohaemoarthrosis and popliteus muscle contusion.

Morale of the story:  In cases of trauma, always look for muscular injuries, always try to obtain an additional X-ray to detect subtle fractures, and always exclude lipohaemoarthrosis which indicates a missed intra-articular fracture.

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Case information

rID: 21462
Published: 24th Jan 2013
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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