Is surgery necessary for Achilles tendon tears?
The short answer is: it depends on the Ultrasound scan.
There was a time when the distinction between indicating surgery or not would depend on the level of activity of the patient, with those sporty and young being operated on the grounds of harder, better, faster and stronger results [song].
This is not the case anymore as non-surgical treatments have evolved and improved outcomes if treated in a boot. Modern studies have shown that with a specific rehabilitation programme, the results are basically equivalent to those operated without the added risks of surgery, the most feared one being infection which may require further plastic surgery and give way to a lengthy recovery.
With the current evidence it appears that non-surgical treatments are equally good* except for those cases when tendon ends do not approximate in the boot or cast, and this will be determined by an ultrasound. Therefore a tendon gap larger than 10mm (5mm in some specific cases) would prompt me to recommend surgery but when it is smaller non-surgical would be my choice.
*Only very small differences seen in recovery time and re-rupture rates, which need to be weighed against the surgical risks during the consultation.