The code to use for Achilles Tendonitis 726.71. 726.73 is for a Calcaneal Spur. 726.71 should be used for Achilles Tendonitis
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The ICD 10 Code for Achilles Tendonitis is M76.60:
http://www.icd10data.com/ICD10CM/Codes/M00-M99/M70-M79/M76-/M76.60
If you do Achilles Tendon debridement for tendonitis the code is 27654
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