Low-volume Hydrodissection for the Treatment of Chronic Achilles Tendinopathy

Chronic Achilles tendinopathy (AT) is a common ailment for many active duty service members that adversely affects readiness. Patients present with pain, swelling, and limited functional ability. Kager's fat pad is a mass of adipose tissue that protects the blood vessels supplying the Achilles tendon and preserves its function. A popular hypothesis is that scarring, tethering, and neovascularization play a significant role in the pathogenesis of AT. Current literature supports the effectiveness of high-volume (40-50 mL) hydrodissection, a procedure in which fluid is injected under ultrasound guidance into the tissues surrounding the Achilles tendon to mechanically separate the paratenon from the underlying Kager's fat pad. There may also be a beneficial effect of scar tissue and neoneurovascular breakdown. However, high-volume injections result in short-term discomfort and decreased mobility. Lowering injection volume (2-10 mL) may reduce this morbidity and facilitate use in limited-resource environments. This case report presents a 29-year-old active duty male with recalcitrant post-traumatic AT who achieved significant pain reduction and faster return to full service using low-volume hydrodissection. The use of 10 mL volume has not been described previously and provides additional support for using lower volumes in chronic AT. This technique is a direct adjunctive treatment option with rehabilitation at a military treatment facility or in the operational environment.