MRI presentation and pathogenesis of tennis legs

Abstract

Objective To evaluate the imaging features of MRI of tennis legs and to explore the pathogenesis of tennis legs. Methods A retrospective analysis was made on the MRI images of 38 patients with tennis legs which met the criteria and were clinically diagnosed in our hospital from May 2014 to June 2018. All patients underwent non-enhanced MRI. Coronal T1WI、T2WI fast spin echo (TSE) and transverse proton density weighted imaging (PDWI) were performed. The signs of fluid collection between gastrocnemius muscle (GM) and soleus muscle (SM),muscle and tendon injuries, superficial vein dilatation of calf were observed and recorded. Results Coronal T1WI, T2WI TSE and transverse PDWI sequences showed 30 (75.0%) places fluid collection (hematoma or effusion) between medial head of the gastrocnemius muscle (MCM) and SM,11 (27.5%) places fluid collection (hematoma or effusion) between lateral head of gastrocnemius muscle (LGM) and SM,7 (17.5%) places fluid collection (hematoma or effusion) in MGM and 2 (5.0%) placesin SM. There were 17 (42.5%) places that hematoma or effusion spread around the fascia of the lower leg. The diameter and thickness of hematoma or effusion are about 1.7-22.3 cm and 0.2-3.5 cm,respectively. Rupture of the GM was seen in 37 (92.5%) places,including 37 places rupture of the MGM at the myotendinous junction, 15 places rupture of the LGM at the myotendinous junction, 24 places tendonrupture of MGM,3 places tendon rupture of MGM and LGM,and 2 places tendon rupture of LGM. The maximum diameter of tendon rupture was 1.2-27.0 mm. The muscle rupture of MGM was seen in one place,and muscle rupture of MGM and LGM was seen in one place at the same time. Rupture of the SM was seen in15 (37.5%) places,including 15 places rupture of the SM at the myotendinous junction, 2 places muscle rupture of SM, 6 places tendonrupture of SM. The maximum diameter of tendon rupture was 2.5-14.9 mm. Rupture of plantaris tendon (PT) was seen in 4 (10.0%) places. Superficial vein dilatation was seen in 3 (7.5%) places. Conclusion This study shows that the rupture of the MGM at the myotendinous junction and the tendon is the main responsibility of tennis leg. Key words: Tennis legs; Gastrocnemius muscle; Plantaris tendon; Soleus muscle