Anugayathri Jawahar MBBS, MD, Presenter: Nothing to Disclose

Yanan Lu MD, Abstract Co-Author: Nothing to Disclose

Gokcan Okur MD, Abstract Co-Author: Nothing to Disclose

Laurie McAdams Lomasney MD, Abstract Co-Author: Consultant, Amirsys, Inc

Gastrocnemius tendinosis (GT) is one potential cause for posterior knee pain, commonly overlooked on clinical examinations and imaging. Tendinosis/tendinopathy is frequently due to chronic repetitive micro trauma to muscle/tendon complex. There is little mention about GT in literature. This study assesses the frequency of GT on MR imaging and potential associated articular pathologies or clinical association.

With IRB approval, retrospective review was done on randomly selected 300 MR knee exams performed from February 2009 to June 2010. Following de-identification, axial T2 and sagittal PD images, with or without fat suppression were reviewed by 2 radiologists. The gastrocnemius tendon femoral attachments were graded as normal, mild (few cysts, thickening, intermediate signal) or severe GT (multiple cysts, marrow edema, tear). Select associated MR findings of internal derangement were documented. Clinical charts were reviewed for clinical presentation, physical exam findings, and select demographics including age, gender, BMI, occupation and recreational activities.

The inter-observer reliability for presence/ grading of GT very high (kappa statistic=0.97). Frequency of GT was 50.33%, most frequently medial head of gastrocnemius (63.6%). Grades of GT were 41.7% and 17.2% for mild and severe respectively. Univariate analysis showed statistically significant relationship between grade of GT with arthrosis (p=0.05) and clinical joint effusion (p=0.02). Multivariate analysis showed significant probability odds for medial plus lateral GT when effusion and posterior knee pain are present, and significant but decreased probability for isolated medial GT. Statistical significance was seen between GT and ACL tear (13.9%; p=0.02) but not for medial meniscal tear, popliteal cyst and chondrosis. Mean age for GT patients was 50.4 years, older than those without (p=<0.001). BMI and gender showed no statistically significant difference between with and without GT.  

Gastrocnemius tendinosis is an under-reported finding on MR knee examinations. Increased understanding of frequency of GT allows more accurate reporting of MR knee exam and systematic search for associated abnormalities.

Awareness of gastrocnemius tendinosis enhances knee MR interpretation, especially in setting of posterior knee pain, and can assist clinical management.

Jawahar, A, Lu, Y, Okur, G, Lomasney, L, Gastrocnemius Tendinosis- An Overlooked Finding on Knee MRI Examinations.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14006267.html