Oral supplementation of specific collagen peptides accelerates improvement in Achilles tendon pain and function in combination with a tailored exercise program

Introduction: At a histological level, tendinopathy is characterized by an imbalance in tendon collagen synthesis and structural fibril degradation. The current pilot study aimed to investigate whether oral supplementation of specific collagen peptides (sCPs) in combination with structured exercise improves symptoms and tendon structure in patients with chronic Achilles tendinopathy.
Methods: In a prospective double-blinded placebo-controlled clinical trial with cross-over design, participants were randomized to 3 months of twice-daily doses of 2.5g sCPs (TENDOFORTE®, GELITA AG, Germany) or a placebo 30 mins before exercise. The ethics committee of the Australian Institute of Sport approved the study design. Group AB received sCPs for the first 3 months before crossing over to placebo. Group BA received placebo first before crossing over to sCPs. All participants followed a twice-daily calf strengthening program and milestone-based return-to-running program for 6 months. At baseline (T1), 3 (T2) and 6 (T3) months, VISA-A questionnaires (Robinson et al 2001) and MRI-based ultrashort echo time (UTE) measurements (Change et al 2015) were obtained in 20 patients with clinical symptoms of uni- or bilateral Achilles tendinopathy. Results: Linear mixed modeling statistics showed that after 3 months, VISA-A increased significantly for group AB with 12.6[95%CI:9.7;15.5], while in group BA VISA-A increased only by 5.3[95%CI:2.3;8.3] points. After crossing over, group AB and BA subsequently showed a significant increase in VISA-A of respectively 5.9 [95%CI:2.8;9.0] and 17.7 [95%CI:14.6;20.7] (Fig. 1). After 3 months, 6 out of 10 participants in group AB and 3 out of 10 participants in group BA successfully returned to running activities. After 6 months these numbers further increased to 7 (group AB) and 5 (group BA) participants respectively (Fig. 2). UTE-based volumetric T2* cluster-analyses (Fig. 3) of non-tendinopathic, moderately and severely tendinopathic zones respectively indicated an improvement in some participants, but data failed to reach level of statistical significance. Conclusion: Although this pilot study has limited statistical power and requires duplication in a larger clinical trial, oral supplementation of sCPs may accelerate the clinical benefits of a well-structured calf strengthening and return-to-running program in patients with chronic Achilles tendinopathy symptoms. Further imaging studies are required to understand the potential in vivo therapeutic working mechanism of sCPs within the human fascial system.