Most studies agree surgery has the best results. Patients get back to normal function faster after surgical repair. There are also fewer cases of re-injury with Achilles tendon re-rupture after surgery.
In general, Achilles tendon ruptures are more common in older athletes. However, younger adults are more likely to reinjure the Achilles after surgery to repair it. Rehab must be approached with more caution than with older adults. It’s not clear what could account for this difference.