Analysis of the clinical and MRI characteristics associated with tennis leg

This study aimed to summarize the MRI characteristics of tennis leg injuries and explore their pathogenesis.

A retrospective analysis was conducted on the clinical and MRI data of 39 patients who were diagnosed with tennis leg at a single institution from February 2021 to August 2025 and were eligible for inclusion. All subjects underwent MRI scans, including FSE coronal T1-weighted, T2-weighted, and axial proton density-weighted sequences. Observations and recordings were made on fluid accumulation (hematoma or effusion) in the gastrocnemius (GM) and soleus muscle (SM) areas. Additionally, we noted muscle belly and tendon tears, fascia tears, and signs of superficial venous varicosities in the calf.

Out of the 39 patients, 21 (53.8%) had injuries to the medial head of the gastrocnemius; 12 (30.8%) had injuries to the medial head along with the soleus muscle; 4 (10.3%) had soleus muscle injuries; 1 (2.6%) had injuries to the lateral head of the gastrocnemius along with the soleus muscle; and 1 (2.6%) had injuries to both the medial and lateral heads of the gastrocnemius. Additionally, 5 cases (12.8%) were grade I injuries, 32 cases (82.1%) were grade II injuries, and 2 cases (5.1%) were grade III injuries. Five cases (13%) had subfascial effusion, 9 cases (23%) had fascia tears, 19 cases (49%) had intermuscular effusion, 5 cases (13%) had intermuscular hematomas, 2 cases (5%) had retraction of the tendon ends, and 2 cases (5%) had superficial venous varicosities in the calf. Grade II injuries accounted for the vast majority (82.1%), suggesting that most patients with tennis leg seen in clinical practice have moderate injuries.

MRI confirms that the main injury in tennis leg is a tear at the tendon-muscle junction of the medial head of the gastrocnemius, often accompanied by coexisting injuries to the soleus muscle. MRI examination can accurately locate the injury, objectively grade it, and identify various complications, providing crucial imaging evidence to help clinicians develop individualized treatment plans (such as determining surgical indications) and assess prognosis.