Injectable Porcine Collagen for Achilles Tendinopathy in Diabetic Patients: A Case Series with Data-Driven Analysis

Background: Achilles tendinopathy (AT) is a debilitating condition with limited therapeutic options in patients contraindicated for corticosteroids. Injective collagen has emerged as a promising alternative, yet evidence in fragile populations such as diabetics remains scarce. Objective: Aim of present work was to evaluate the clinical effectiveness of Porcine collagen injections in diabetic patients with chronic AT, looking for the pain reduction and increase of functionality. Methods: Twenty-two diabetic patients with degenerative Achilles tendinopathy unresponsive to treatment were included were splited in two groups, according the type of AT pathology: Insertional (I) and non-insertional (NI). Patients received five weekly peritendinous injections of porcine collagen. Outcome measures included VAS (baseline, post-2nd injection, 1 month, 6 months), VISA-A at 6 months, return-to-activity time and adverse events monitoring. Additional variables included BMI, HbA1c, symptom duration, and previous treatments. Analyses included descriptive statistics, paired t-tests, regression models, and ANOVA tests. Results: All patients completed the protocol with no adverse events. Mean VAS decreased significantly from baseline to 6 months in both AT-I and AT-NI patients (mean delta VAS: 5.1 and 4.4, respectively; p=0.001). Mean delta VISA-A scores were 32.78 and 38.97 in AT-I and AT-NI (p<0.0001) and median return to work (RTW) were 37 and 35 days in AT-I and AT-NI, respectively (p=ns). No significant differences were discovered comparing AT-I vs AT-NI, in terms both VAS and VISA-A variation per ml of injected product (p=ns). Conclusions: Porcine collagen is a safe, effective, and sustainable treatment for Achilles tendinopathy in diabetic patients with both AT-I and AT-NI conditions. This study supports its adoption as a first-line of conservative approach for pain reduction and functionality improvement.