Case 24 - 22 year old male with fall onto anterior knee playing basketball
22 year old male with fall onto the anterior left knee while playing basketball one month prior.
- This case is a bit trickier than the last; due to the timing of the injury we don't have much edema to guide our search.
- The history of a fall onto a flexed knee, however, is typical and merits close inspection of the posterior cruciate ligament. Indeed, there is complete disruption of the PCL fibers at the genu, best seen on the sagittal PD images. This thickened, irregular, high signal pseudomass replacing the mid-PCL is also well seen on axial images; compare the abnormal PCL to the normal hypointense fibers of the ACL.
- The only associated findings are a small joint effusion and focal high signal within the posterior horn of the medial meniscus, likely representing a meniscal contusion.
- Given the imaging findings and timing of the injury this patient has a subacute to chronic PCL tear.
In the setting of a PCL tear it is importantly to careful assess for the presence of meniscal tears or additional ligamentous injuries. Depending on the degree of instability on exam, isolated PCL tears can sometimes be managed conservatively, whereas patients with multiple ligamentous injuries typically require surgical repair. While MRI is sensitive for PCL injuries it can sometimes be difficult to differentiate a complete tear from a near-complete tear.
Accession: CL0060
Study description: MR JOINT LOWER KNEE-LT
Case discussion: