Assessment of post-operative menisci on MR imaging (MRI) is difficult and meniscal re-tear is not easy to recognize and make a straightforward call.
We describe MRI criteria of meniscal re-tear and present MRI appearance after meniscal sutures (both normal and abnormal).
Besides traditional partial meniscectomies,
there has been an increasing number of meniscal repairs (sutures) being performed.
persistent pain is a common problem amongst these patients.
This often requires further evaluation with MRI to assess a re-tear,
but conventional criteria of meniscal tear cannot be applied strictly to post-operative menisci. Therefore,
it is important for the radiologist to recognize normal and abnormal imaging findings of meniscal sutures.
Findings and procedure details
Normal meniscal sutures appear with maintained morphology and high / intermediate signal intensity in T1- and PD-weighted images (WI) but not in T2-WI (that is,
is not “fluid-like”) at the site of repair.
Scar tissue at the repair site frequently leads to linear signal abnormalities on PD-WI,
despite absence of re-tear1.
These findings persist in 50% of the patients,
with a mean follow-up of 12.9 years2.
Different sutures will have distinct imaging features.
Inside-out sutures originate pronounced signal variation and are magnetically susceptible,
Evaluation of post-operative knee is often a challenge.
Radiologist should be familiar with relevant information,
such as clinical findings (if there is persistence and/or new meniscal symptoms),
arthroscopic protocol and prior MRI studies.
Not all recurrent pain after meniscal repair surgery is a retorn meniscus.
MRI plays an important role on assessment of post-operative menisci,
and radiologists should be familiar with normal and abnormal imaging findings in these cases of meniscal sutures.
R et al.
MR Imaging of the Postoperative Knee.
JOURNAL OF MAGNETIC RESONANCE IMAGING 34:1007–1021 (2011)
2 Muellner T,
Open meniscal repair: Clinical and magnetic resonance imaging findings after twelve years.
Am J Sports Med 1999;27:16-20.
P et al.
Imaging of the postoperative knee. Diagnostic and Interventional Imaging (2016) 97,
MR Imaging of the Postoperative Knee: A Pictorial Essay.
RadioGraphics 2002; 22:765–774
R et al....