Injectable Porcine Collagen in Musculoskeletal Disorders: A Delphi Consensus

Musculoskeletal disorders causing chronic pain are increasingly prevalent due to factors such as injury, overuse, and aging, leading to interest in porcine collagen injections as a potential therapeutic and conservative option. Despite promising results, evidence-based information on this treatment is scarce. To address this gap, the authors conducted an eDelphi consensus among expert Italian physicians in musculoskeletal pain to gather their perspectives on collagen injections.

A Steering Committee and a Panel of 23 physicians developed the statements list (36) including the modalities, safety, and efficacy of intra- and extra-articular collagen injections. Panelists rated their agreement with each statement on a 5-point Likert scale (5 means "Strong Agreement"). Consensus was defined as when at least 75% of the panelists voted with a score of ≥4/5 after two rounds of votes. The weighted average (WA) was calculated for each statement. As control, we elaborated a Hypothetical Parametric Distribution (HPD WA equal to 3.00), where the percent of panelists is equally distributed along each Likert Scale Value (LSV). The maximum WA for 75% of the consensus is established at 3.75. Indeed, the combination of 75% having WA > 3.75 was defined as "Strong Agreement". While, if the consensus was under 75%, the WA vs. HPD comparison was performed using the Wilcoxon Test. Significant differences among the distribution of LSVs judged the statement as "Low Level of Agreement". Disagreement was evaluated when the WA was under the PHD.

The consensus was reached "Strong Agreement" after twin rounds in 29 out of 36 (8.55%). In 5 out of 36 statements (13.89%), the panelists reached the "Low Level of Agreement" by statistical tests. In the remaining two statements, there was a "Consensus of Disagreement". All panelists unanimously agreed on crucial points, such as contraindications, non-contraindication based solely on comorbidity, and the importance of monitoring collagen's effectiveness. Unanimous agreement was reached on recommending ultrasound guidance and associating collagen injections with therapeutic exercise and physical modalities. Substantial consensus (concordance > 90%) supported collagen injections for osteoarthritis, chondropathy, and degenerative tendinopathies, emphasizing intra- and peri-articular treatment, even simultaneously. However, areas with limited evidence, such as the combination of collagen with other injectable drugs, treatment of myofascial syndrome, and injection frequency, showed disagreement. The potential of intra-tendinous porcine collagen injections for tendon regeneration yielded mixed results.

Clinicians experts in musculoskeletal pain agree on using collagen injections to treat pain originating from joints (e.g., osteoarthritis) and periarticular (e.g., tendinopathies).