Micronized Dehydrated Amnion Chorion Membrane (mdHACM) Injection in the Treatment of Chronic Achilles Tendinitis: A Large Retrospective Case Series

Background: Human amniotic membrane contains growth factors and cytokines that promote epithelial cell migration and proliferation, stimulate metabolic processes that lead to collagen synthesis, and attract fibroblasts, while also reducing pain and inflammation. Randomized studies have shown effectiveness of micronized dehydrated human amnion/chorion membrane (mdHACM) allograft injection in treatment of plantar fasciitis. We present our experience and short-term outcomes with using mdHACM injection as a treatment for Achilles tendinopathy. Methods: Retrospective case series of patients with Achilles tendinopathy treated with mdHACM by a single physician. Participants had at least two follow-up visits within 45 days of mdHACM injection. Outcomes examined included change in reported level of pain during the 45-day observation period and treatment-associated adverse events. Results: Follow-up data were available for 32 mdHACM-treated patients. At treatment initiation, 97% of patients reported severe (66%) or moderate (31%) pain. At the first follow-up visit (mean ± SD of 8.1 ± 2.7 days postinjection), 27 patients (84%) reported improvement in pain levels, although 37% of patients continued to report severe (6%) or moderate (31%) pain. At the second follow-up visit (mean ± SD of 23.1 ± 6.2 days postinjection), no patients reported severe pain and one reported moderate pain. Within 45 days of mdHACM injection, complete symptom resolution was reported by 66% of treated patients (n = 21), with the remaining 34% (n = 11) reporting symptom improvement but not complete resolution. Two patients reported calf or quadricep pain or tightness after injection. Conclusions: In our experience, mdHACM injection reduced or eliminated pain in all 32 patients with follow-up data.