Tendinopathic Plantaris but Normal Achilles Tendon Found in About One-Fifth of Patients Not Responding to Conservative Achilles Tendon Management - Results from a Prospective WALANT Surgical Case Series on 105 Tendons.

Purpose: Midportion Achilles tendinopathy is a relatively common condition. This study aimed to investigate the presence of a normal Achilles tendon, but a tendinopathic plantaris tendon, in a large and consecutive prospective sample of patients referred to a specialised tendon clinic for midportion Achilles tendon pain not responding to non-surgical treatment. Patients and Methods: A total of 105 consecutive tendons were operated on in 81 patients (62 males) suffering from painful midportion Achilles tendon pain. Clinical examination, ultrasound (US) and colour Doppler (CD) examination, and wide awake local anaesthetic no tourniquet (WALANT) surgery were performed in all patients. Results: For 19/105 (18%) tendons from 14 patients, clinical examination suspected plantaris tendinopathy alone as there was a distinct tenderness on the medial side, but no thickening of the Achilles tendon. US examination followed by surgery confirmed the diagnosis. Conclusion: Midportion Achilles tendon pain is not always related to Achilles tendinopathy since pain related to the plantaris tendon alone was found in almost every fifth patient. Consequently, there is an obvious need for proper examination to identify the pain source and establish a correct diagnosis before treatment.