Dr. Tracey Isidro, Stacey Isidro, Dr. John Cianca
Baylor College of Medicine
Introduction: The plantaris is a plantar flexor that is superficial to the soleus and deep to the gastrocnemius. It inserts on the calcaneus medial to the Achilles tendon. Plantaris tendon tears are painful though not debilitating whereas ruptures may cause decreased function and difficulty with weightbearing for 2-3 weeks. Plantaris tears have a decreased incidence compared to Achilles tendon injuries.
Methods/Case Description: We present the case of a 29-year-old elite level Scottish Highland female dancer with a history of acute overuse injury secondary to Scottish Highland dancing. She had distal right leg pain and tendon tightness that was worsened by dancing during a competition three days prior to presentation. The pain radiated up the medial side of the right calf with mild tenderness in the proximal portion of the Achilles tendon eventually making weightbearing difficult. She did not hear or feel a pop at that time. Previous providers initially diagnosed her right posterior lower leg pain as Achilles tendinopathy and later as a gastrocsoleus strain.
Results: On exam she was able to bear weight with mild discomfort. There was tightness in the distal right posterior leg and pain with passive range of motion that worsened with knee flexion. Further, there was tenderness along the mid to distal portion of the Achilles tendon with mild proximal tenderness at the gastro-Achilles junction. Active plantar flexion increased pain in the Achilles region rather than the gastrocnemius. Ultrasound revealed an enlarged plantaris tendon with associated edema, Achilles tendinopathy, and a normal gastrocnemius. MRI showed a partial tear of the plantaris tendon with soft tissue edema, mild thickening without tear or tendonitis of the Achilles tendon, and a normal gastrocnemius. We diagnosed her with a partial plantaris tendon tear at the distal soleus and recommended conservative management.
Conclusion: Partial plantaris tendon tears are uncommon and may be confused with Achilles tendinopathy or gastrocsoleus injuries.