Does the Use of Injectable Atelocollagen during Arthroscopic Rotator Cuff Repair Improve Clinical and Structural Outcomes?

Soluble allogeneic telocollagen as a direct protein therapeutic: results of serial injections in a rodent rotator cuff tear model

HYPOTHESIS

Delivery of soluble allogeneic type I telocollagen (allo-telocollagen) will accelerate and improve the healing of damaged tendons. Our hypothesis draws from known mechanochemical properties of type I collagen that direct its incorporation into damaged connective tissue. We further suggest that allo-telocollagen will raise a minimal immunogenic reaction as a result of homology within species.

METHODS

Seventy-eight shoulders (39 Sprague-Dawley rats) had their supraspinatus tendon surgically detached from its footprint on the humerus and repaired (72 shoulders) or left uninjured (6 shoulders). The repaired tissue was treated with an injection of 100 μL of saline, 10 mg/mL allogeneic atelocollagen (allo-atelocollagen), or 10 mg/mL allo-telocollagen at 0, 1, and 2 weeks postsurgery. At 30 and 60 days postsurgery, the tendons were assessed by mechanical testing (failure load, failure stress, stiffness, and relaxation) and by semiquantitative histologic scoring.

RESULTS

At 30 days postsurgery, the mechanical and histologic outcomes were not statistically different. However, at day 60, allo-telocollagen improved the failure strength of the supraspinatus (29.9 ± 4.7 N) relative to saline (20.0 ± 3.5 N, P < .001) or allo-atelocollagen (23.2 ± 1.5 N, P = .025) treated tendons, and it approached that of uninjured controls (36.9 ± 5.0 N, P = .021). Allo-telocollagen improved the failure stress of the supraspinatus (34.1 ± 9.3 MPa) relative to the saline-treated tendons (21.4 ± 6.0 MPa, P = .031, 160% improvement) and was no different than uninjured controls (33.4 ± 9.9 MPa, P = .999) or allo-atelocollagen (32.3 ± 7.4 MPa, P = .977). The stiffness of uninjured controls was far greater than any of injured or treated tendons (>200% stiffer). Histologic scoring showed that the allo-telocollagen-treated tendons produced better collagen fiber arrangement (1.55 ± 0.17) than saline (2.50 ± 0.29, P = .001) or allo-atelocollagen (2.23 ± 0.28, P = .042) treated tendons and that it did not increase markers of immunogenesis (1.10 ± 0.42) relative to either saline (1.44 ± 0.20, P = .369) or allo-atelocollagen (0.68 ± 0.41, P = .1058).

CONCLUSIONS

Although all 3 treatments produced similar results at 30 days, by 60 days, soluble allo-telocollagen clearly separated from the other interventions, yielding better mechanical and histologic outcomes in a torn or repaired rotator cuff rat model. Allo-telocollagen-treated tendons also approached the failure strength and matched the failure stresses of uninjured control tendons. The data suggest a new use for allo-telocollagen as a deliverable direct protein mechanotherapeutic that can improve both healing quality and speed.

Bone Marrow Aspirate Concentrate Combined With an Appropriate Carrier Effectively Promotes Bone-Tendon Interface Healing in a Rabbit Model of Chronic Rotator Cuff Tear

BACKGROUND

The efficacy of bone marrow aspirate concentrate (BMAC) in promoting bone-tendon interface (BTI) healing without any carriers remains a subject of debate.

PURPOSE

To evaluate BMAC effects with different carriers on tendon regeneration in a rabbit model of chronic rotator cuff tear.

STUDY DESIGN

Controlled laboratory study.

METHODS

In vitro, the amount of growth factor and the differentiation potential of BMAC with different carriers (polydeoxyribonucleotide [PDRN] and atelocollagen [ATC]) were assessed. In vivo, 64 rabbits were randomly allocated into 4 groups. Different materials were injected into the repair site according to the allocated group: control, saline; BMAC, BMAC and saline; BMAC-PDRN, BMAC with PDRN; BMAC-ATC, BMAC with ATC (n = 16 in each). Genetic and histologic analyses were conducted at 4 and 12 weeks after repair, while biomechanical evaluations were performed at 12 weeks after repair.

RESULTS

In vitro, the degree of multilineage differentiation was much stronger using BMAC with ATC as compared with administration of BMAC alone or BMAC with PDRN (P < .001). In vivo, the BMAC-ATC group had the highest levels of aggrecan expression, bone morphogenetic protein 2, and collagen type I alpha 1 among all groups (all P < .001) at 4 weeks after repair. Furthermore, the BMAC-ATC group showed collagen fiber continuity, denser collagen fibers, and more mature BTI as compared with the other groups (all P < .001) at 12 weeks after repair. Concurrently, the BMAC-ATC group also demonstrated significantly higher load-to-failure versus the remaining groups (all P < .001) at 12 weeks after repair.

CONCLUSION

Local application of BMAC without appropriate carriers could not enhance BTI healing. However, BMAC with 2 different carriers effectively accelerated BTI healing, particularly in the ATC environment. Therefore, the combination of BMAC and ATC may act as a powerful biological agent to promote healing after rotator cuff repair in a chronic rotator cuff tear model using rabbits.

CLINICAL RELEVANCE

Local application of BMAC without appropriate carriers could not enhance BTI healing. However, the combination of BMAC and ATC may synergistically promote rotator cuff tendon healing.

Collagen Injections for Rotator Cuff Diseases: A Systematic Review

BACKGROUND

Because of its anatomy and function, the rotator cuff (RC) is vulnerable to considerable morbidity. The prevalence of RC diseases (RCDs) among the general population is 5-39%, reaching over 30% in patients older than 60. The aim of the present systematic review is to investigate the effects of the use of collagen injections in the treatment of RCDs.

METHODS

A systematic search of scientific electronic databases (such as PubMed, Scopus and Web of Science) was performed up to November 2024, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two independent authors conducted the search and assessed the articles. The inter-rater reliability for the quality assessment was measured using Cohen's kappa coefficient, while the Modified Coleman Methodology Score (CMS) was applied to evaluate the methodological quality of the articles included in this systematic review.

RESULTS

A total of eight articles were included, with the overall quality of the included articles being evaluated as fair. Despite the use of different types of collagen and injection protocols, as well as the different scores applied, each included study showed clinically relevant improvements. However, given the high degree of heterogeneity of the included studies, we cannot draw conclusions regarding which type of collagen and injection protocol are best for RCD treatment.

DISCUSSION

Collagen administration for RCDs seems to be effective at reducing pain and improving function, as well as the tendon structure, especially in partial tears and RC tendinopathy. High-quality, prospective studies with long-term follow-up are necessary to validate the findings of the articles included in this systematic review.

Atelocollagen Injection During Arthroscopic Rotator Cuff Repair for Small- to Medium-Sized Subacute or Chronic Rotator Cuff Tears Enhances Radiographic Tendon Integrity: A Propensity Score-Matched Comparative Study

PURPOSE

To evaluate the clinical and structural outcomes of using injectable atelocollagen during arthroscopic rotator cuff repair (ARCR) for small- to medium-sized rotator cuff tears.

METHODS

This retrospective study reviewed patients with small- to medium-sized full-thickness tears who underwent ARCR from 2016 to 2022 with a minimum 1-year follow-up. Propensity score (PS) matching was used to reduce bias. Tendon integrity was evaluated using magnetic resonance imaging (MRI) at postoperative 6 months. Clinical and structural outcomes were compared between the 2 groups.

RESULTS

After PS matching, this study included 181 pairs of patients comparing ARCR with atelocollagen injection and without atelocollagen injection. Range of motion, muscle strength, and functional outcomes were significantly improved in both the atelocollagen group and the control group. Forward elevation and external rotation were significantly worse in the atelocollagen group compared with the control group at 2, 6, and 12 months postoperatively and at the final follow-up. In total, 125 patients (69.1%) in the atelocollagen group and 130 patients (71.8%) in the control group exceeded the minimal clinically important difference in the American Shoulder and Elbow Surgeons score without a significant difference between the 2 groups (P = .509). The mean value of Sugaya grade on postoperative MRI evaluation was 2.03 ± 0.81 for the atelocollagen group and 2.24 ± 0.97 for the control group, with a significant difference between the 2 groups (P = .027). Tendon healing failure was observed in 12 patients (6.6%) in the atelocollagen group and 19 patients (10.5%) in the control group, with no statistical difference between the 2 groups (P = .189).

CONCLUSIONS

Atelocollagen injection during ARCR for small- to medium-sized subacute or chronic rotator cuff tears did not show a benefit in clinical outcomes. However, postoperative MRI showed significantly lower Sugaya grade compared with the control group, with no significant difference in retear rate.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

Effect of Porcine-Derived Absorbable Patch-Type Atelocollagen for Arthroscopic Rotator Cuff Repair: A Prospective Randomized Controlled Trial

BACKGROUND

Even though arthroscopic rotator cuff repair is recognized as a standard treatment option, the risk of postoperative retear is a major concern.

PURPOSE

To evaluate the effect of porcine-derived absorbable patch-type atelocollagen during arthroscopic rotator cuff repair.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 64 patients with rotator cuff tears diagnosed on magnetic resonance imaging (MRI) were enrolled prospectively from November 2020 to December 2021. Both groups had repairs using the suture bridge technique. For the atelocollagen group, before securing the lateral anchors, we inserted porcine-derived absorbable patch-type atelocollagen between the footprint and the tendon. On postoperative day 2, the patients underwent MRI to confirm containment of the patch-type atelocollagen. At 6 months and 1 year postoperatively, the signal intensity of the repaired tendon was assessed using MRI. Patients were evaluated using the Constant score as the primary outcome, along with the visual analog scale for pain; range of motion; American Shoulder and Elbow Surgeons score; University of California, Los Angeles, score; and Korean Shoulder Score preoperatively and at 2, 3, 6, and 12 months postoperatively.

RESULTS

No significant changes in the Constant score as primary outcome, pain or other functional scores, and range of motion were observed between the groups at 1 year postoperatively. The patch-type atelocollagen was confirmed to be contained by the time-zero MRI scan taken 2 days postoperatively. Among the 55 patients included in final analysis, 12 retear cases were recorded (21.8% retear rate). A significantly lower retear rate was found in the atelocollagen group, as 3 cases were observed in this group (10.3%) and 9 cases were observed in the conventional repair group (34.6%) (P = .048).

CONCLUSION

The Constant score was not different between the groups. The retear rate after rotator cuff repair was significantly lower in the group that received porcine-derived absorbable patch-type atelocollagen compared with in the conventional group.

REGISTRATION

KCT0005184 (Clinical Research Information Service [CRIS]; https://cris.nih.go.kr).

A multi-channel collagen conduit with aligned Schwann cells and endothelial cells for enhanced neuronal regeneration in spinal cord injury

Traumatic spinal cord injury (SCI) leads to Wallerian degeneration and the accompanying disruption of vasculature leads to ischemia, which damages motor and sensory function. Therefore, understanding the biological environment during regeneration is essential to promote neuronal regeneration and overcome this phenomenon. The band of Büngner is a structure of an aligned Schwann cell (SC) band that guides axon elongation providing a natural recovery environment. During axon elongation, SCs promote axon elongation while migrating along neovessels (endothelial cells [ECs]). To model this, we used extrusion 3D bioprinting to develop a multi-channel conduit (MCC) using collagen for the matrix region and sacrificial alginate to make the channel. The MCC was fabricated with a structure in which SCs and ECs were longitudinally aligned to mimic the sophisticated recovering SCI conditions. Also, we produced an MCC with different numbers of channels. The aligned SCs and ECs in the 9-channel conduit (9MCC-SE) were more biocompatible and led to more proliferation than the 5-channel conduit (5MCC-SE) in vitro. Also, the 9MCC-SE resulted in a greater healing effect than the 5MCC-SE with respect to neuronal regeneration, remyelination, inflammation, and angiogenesis in vivo. The above tissue recovery results led to motor function repair. Our results show that our 9MCC-SE model represents a new therapeutic strategy for SCI.

Effects of Arthroscopic Atelocollagen Insertion in High-Grade Partial Articular Supraspinatus Tendon Avulsion Lesions: A Retrospective Cohort Study With Propensity Score Matching

Background

This study sought to evaluate the effect of atelocollagen insertion into the bone-tendon interface of the repaired tendon after arthroscopic rotator cuff repair for high-grade partial articular supraspinatus tendon avulsion (PASTA) lesions.

Purpose

To compare clinical and radiological outcomes of atelocollagen-inserted rotator cuff repair and atelocollagen-noninserted rotator cuff repair in the high-grade PASTA lesions.

Study Design

Cohort study; Level of evidence, 3.

Methods

The data from 301 consecutive patients who underwent arthroscopic rotator cuff repair of PASTA lesions between January 2017 and June 2020 were retrospectively reviewed. Patients with minimum 2-year follow-up data were included and divided into 2 groups: those treated with transtendon suture-bridge repair without additional augmentation (group 1) and those with atelocollagen-inserted transtendon suture-bridge repair (group 2). Patients in group 2 were matched 1:1 to patients in group 1 using propensity score matching (n = 68 per group); and pain visual analog scale, American Shoulder and Elbow Surgeons, University of California, Los Angeles, Korean Shoulder Scoring System, Simple Shoulder Test, and range of motion scores were compared between these groups. Also, repaired tendon integrity and thickness were compared immediately, 6 months, and 1 year after surgery on magnetic resonance imaging (MRI) using the vertical distance from the midpoint footprint of the greater tuberosity.

Results

In most comparisons, there were no significant differences in outcome measures and range of motion between groups. However, less residual discomfort at the final follow-up was also documented in group 2 (P = .043). Also, the difference in forward flexion was 3.7° at 1 year and 5.4° at final follow-up, and the difference in abduction was 2.2° at final follow-up, which were all significantly greater in the experimental group. Group 2 showed significant greater tendon thickness of the repaired tendon immediately, 6 months, and 1 year after surgery on MRI (P≤ .001).

Conclusion

Addition of atelocollagen did not improve outcome scores. However, there was slightly greater flexion and abduction at final follow-up. Also, there was less residual discomfort at final follow-up.

Outcome of intraoperative injection of collagen in arthroscopic repair of full-thickness rotator cuff tear: a retrospective cohort study

BACKGROUND

Rotator cuff (RC) pathologies are considered the most common cause of shoulder disability and pain. Arthroscopic repair of RC tears has proven to be an effective operation. Nonhealing and retear remain significant clinical problems and a challenge to surgeons. In addition, the essential biological augment to enhance RC tendon-bone healing is still under research. The purpose of the study was to assess the safety and efficacy of injection of atelocollagen and acellular dermal matrix (ADM) allograft in arthroscopic repair of full-thickness RC tears.

METHODS

From January 2018 to March 2020, a total of 129 patients with full-thickness RC tear were treated by arthroscopic repair only (group 1, n = 36, with a mean age = 63.2 years), arthroscopic repair together with atelocollagen 1-mL injection (group 2, n = 44, with a mean age = 63 years), or RC tears together with ADM allograft 1-mL injection (group 3, n = 49, with a mean age = 64.6 years). They were prospectively studied. This study included patients with a repairable full-thickness tear of the supraspinatus tendon size <5 cm. We excluded patients with isolated tears of the subscapularis tendon, those with a previous shoulder surgery, and those who had any type of injection for less than 6 weeks. American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score, Constant Shoulder score, visual analog scale pain score, and range of motion were evaluated preoperatively, at 3, 6, and 12 months of the postoperative period and the final follow-up. In addition, magnetic resonance imaging was performed at 2 months and 12 months postoperatively.

RESULTS

The mean follow-up period was 20 months. All groups showed improvement in functional and pain score at the final follow-up; however, there is no superior outcome among the 3 groups (P > .05). After 2 months, the nonhealing rate was 11% (4 of 36) for group 1, 4% (2 of 44) for group 2, and 2% (1 of 49) for group 3 (P > .05). The retear rates after 12 months was 19.4% (7 of 36) for group 1, 13.6% (6 of 44) for group 2, and 20.4% (10 of 49) for group 3 (P > .05). Adverse events were not detected in any groups.

CONCLUSION

Our study did not show superior clinical or radiologic outcomes of atelocollagen and ADM allograft injections in arthroscopic RC repair over 12 months of follow-up in comparison to the control group. However, adverse events related to atelocollagen and ADM allograft injection were not observed.