Diagnostic domains, differential diagnosis and conditions requiring further medical attention that are considered important in the assessment for Achilles tendinopathy: a Delphi consensus study

The absence of agreed methods to diagnose Achilles tendinopathy impedes research and clinical practice. This gap results in heterogeneous and/or poorly described study samples, making it challenging to apply findings in clinical practice. The aim of this Delphi study was to define consensus on (1) diagnostic domains; (2) differential diagnoses; and (3) conditions requiring further medical attention, when assessing for Achilles tendinopathy. We conducted a sequential three-stage process which included: (1) identifying diagnostic domains, differential diagnoses and conditions requiring further medical attention based on existing scoping reviews and clinical practice guidelines; (2) developing Delphi survey questions; and (3) administering a five-round Delphi online survey. Consensus was defined as ≥70% agreement. 52 participants completed the surveys. Four diagnostic domains were deemed essential and reached consensus (pain location (93%); pain during activity (97%); tests that provoke pain (87%); palpation to assess pain (83%)). 15 differential diagnoses reached consensus: 2 for both midportion and insertional (partial tear (80%); posterior ankle impingement (78%)), 6 for midportion (plantaris tendinopathy (84%); tibialis posterior or flexor hallucis longus tendinopathy/tenosynovitis (72%); flexor digitorum longus tendinopathy (77%); accessory soleus muscle (74%); paratendinopathy (86%); sural nerve neuropathy (81%)) and 7 for insertional (superficial (88%) and retrocalcaneal bursitis (86%); Haglund's/calcaneal exostosis (80%), intratendinous calcifications (73%); Sever's disease (78%); calcaneal stress reaction/fracture (80%); subtalar/ankle pain (71%)). Six conditions requiring further medical attention reached consensus: (Achilles tendon rupture (83%); systemic inflammatory joint disease (86%); metabolic syndrome (75%); familial hypercholesterolaemia (77%); endocrine and hormonal disorders (80%); drug reactions (77%)). This consensus identified essential diagnostic domains, differential diagnoses and conditions requiring further medical attention that should be considered when assessing for Achilles tendinopathy.