Evaluation of High-Purity Type I Collagen Biologic Wrap to Improve Function After Extensor Tendon Repair of the Hand

A Randomized Controlled Trial Evaluating High-Purity Type I Collagen Wrap Around Extensor Tendon Repair Sites in Zones VI-VIII of the Hand to Prevent Adhesions and Improve Functional Outcomes

Tendon injuries of the hand, particularly extensor tendons, are prone to postoperative adhesions, extensor lag, and stiffness, leading to functional impairment. This multicentric randomized controlled trial evaluates whether wrapping repaired extensor tendons with a high-purity Type I collagen (HPTC) biologic membrane can reduce adhesion formation and improve functional outcomes compared with standard repair alone.

Extensor tendon injuries of the hand are common due to the superficial location of the tendons and the thin soft tissue envelope over the dorsum of the hand and wrist. These injuries, particularly in zones VI-VIII, are frequently associated with postoperative adhesions and extensor lag, leading to functional impairment and delayed return to work. Postsurgical adhesions may occur in up to 30-40% of tendon injuries and remain a major clinical challenge despite advances in suture techniques and rehabilitation protocols.

Several strategies have been investigated to minimize tendon adhesions, including optimized suture techniques, early mobilization, anti-adhesive agents, and biologic barrier membranes. Recent clinical work has shown that wrapping repaired extensor tendons with an amniotic membrane in zone VI can improve range of motion (ROM), Quick DASH scores, and recovery time, suggesting a true reduction in peritendinous fibrosis. Experimental models have also demonstrated that collagen-glycosaminoglycan (GAG) wraps can reduce early postoperative tendon adhesions while preserving tendon healing strength.

HPTC is a bioengineered, acellular dermal replacement product composed of >97% pure Type I collagen, free of elastin, lipids, and immunogenic proteins. It is manufactured to preserve the native triple helical structure and bioactivity of collagen, providing a cell-conducive scaffold that promotes neovascularization, granulation tissue formation, and tissue remodelling. HPTC is flexible, translucent, moderately tacky, and can be cut, sutured or stapled, making it feasible to be fashioned as a wrap or sleeve around tendons.

Multiple randomized controlled trials and clinical series by Narayan et al. have demonstrated the safety and efficacy of high-purity Type I collagen-based skin substitute HPTC in chronic and acute wounds.

These studies collectively show that high-purity Type I collagen membranes are safe, well tolerated, promote faster wound healing, and have favourable scarring and pain profiles in a variety of clinical settings.

Rationale for the Current Study - Given the strong biological plausibility of Type I collagen scaffolds as biocompatible, resorbable barriers that can modulate the healing milieu; the safety and clinical efficacy of HPTC in multiple wound types; and the demonstrated benefit of biologic wraps (e.g., amniotic membrane) around extensor tendon repairs in reducing adhesions, it is logical to evaluate whether a HPTC wrap around the repaired extensor tendon in zones VI-VIII can reduce adhesion-related stiffness and improve functional outcomes compared with standard repair alone.

This trial will be, to our knowledge, the first prospective randomized clinical trial to assess HPTC as a tendon wrap in extensor tendon repairs of the hand.

Inclusion Criteria:

1. Age 18-65 years.
2. Acute open laceration of extensor tendons in zone VI, VII, or VIII of the hand / wrist (according to Verdan's classification), involving digits 2-5 and/or wrist extensors.
3. Complete tendon laceration (≥50% tendon cross-sectional area), requiring primary repair.
4. Time from injury to surgical repair ≤72 hours.
5. Single upper limb involved.
6. Ability and willingness to comply with postoperative rehabilitation protocol and follow-up visits.
7. Provision of written informed consent.

Exclusion Criteria:

1. Crush, avulsion, or segmental tendon loss requiring graft or tendon transfer.
2. Associated open fractures requiring dorsal plating across the repair site, or extensive bone loss affecting joint stability.
3. Previous surgery or significant scarring over the injured extensor tendon region.
4. Associated major nerve injury requiring graft or complex reconstruction (digital nerve repair without grafting may be allowed if balanced between groups).
5. Uncontrolled systemic illness (e.g., HbA1c > 8.5% for diabetes, severe peripheral vascular disease, chronic steroid use, severe malnutrition).
6. Active infection at the injury site.
7. Known allergy or hypersensitivity to bovine/ovine collagen or any component of HPTC.
8. Pregnancy or lactation.
9. Inability to provide informed consent or comply with follow-up.