Effect of co-administration of atelocollagen and hyaluronic acid on rotator cuff healing

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 magnetic microbeads on sustained and targeted delivery of transforming growth factor-beta-1 for rotator cuff healing in a rat rotator cuff repair model

Structural failure is a well-established complication of rotator cuff repair procedures. To evaluate the effect of magnetic microbeads, designed for precise drug delivery via magnetic force, on sustained transforming growth factor-beta-1 (TGF-β1) release and rotator cuff healing in a rat rotator cuff repair model. TGF-β1 laden microbeads were prepared, and baseline in vitro experiments included the magnetization of the microbeads and TGF-β1 release tests. In an in vivo experiment using a rat rotator cuff repair model on both shoulders, 72 rats were randomly assigned to three groups (24 per group): group A, conventional repair; group B, repair with and simple TGF-β1 injection; and group C, repair with magnet insertion into the humeral head and TGF-β1 laden microbead injection. Delivery of TGF-β1 was evaluated at 1 and 7 days after the intervention using PCR, Western blot, and immunohistochemistry. At 6 weeks post-intervention, rotator cuff healing was assessed using biomechanical and histological analysis. The in vitro experiments confirmed the magnetization property of the microbeads and sustained delivery of TGF-β1 for up to 10 days. No difference in the TGF-β1 expression was found at day 1 in vivo. However, at day 7, group C exhibited a significantly elevated expression of TGF-β1 in both PCR and Western blot analyses compared to groups A and B (all P < 0.05). Immunohistochemical analysis revealed a higher expression of TGF-β1 at the repair site in group C on day 7. At 6 weeks, biomechanical analysis demonstrated a significantly higher ultimate failure load in group C than in groups A and B (P < 0.05) and greater stiffness than in group A (P = 0.045). In addition, histological analysis showed denser and more regular collagen fibers with complete continuity to the bone in group C than in groups A and B, a statistically significant difference according to the semi-quantitative scoring system (all P < 0.05). The use of the TGF-β1 laden magnetic microbeads demonstrated sustained delivery of TGF-β1 to the repair site, improving rotator cuff healing.

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).

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.

Types and doses of anti-adhesive agents injected into subacromial space do not have an effect on the clinical and anatomical outcomes after arthroscopic rotator cuff repair

PURPOSE

Joint stiffness after arthroscopic rotator cuff repair is a major concern for orthopaedic surgeons. Various antiadhesive agents are commonly administered after rotator cuff repair for its prevention. This study aimed to compare the outcomes among patients injected with different types and amounts of anti-adhesive agents after rotator cuff repair. It was hypothesized that the outcomes might differ depending on the use of the anti-adhesive agent and its type and dose.

METHODS

A total of 267 patients who underwent arthroscopic rotator cuff repair with or without subacromial injection of anti-adhesive agents were enrolled. The first group (group A; 51 patients) were injected with 3 mL of poloxamer/sodium alginate-based anti-adhesive agent. The second group (group B; 93 patients) were injected with 3 mL of sodium hyaluronate-based anti-adhesive agent. The third group (group C; 82 patients) were injected with 1.5 mL of sodium hyaluronate-based anti-adhesive agent. Finally, the last group (group D; 41 patients) who did not use anti-adhesive agents served as the control. The range of motion (ROM) and pain VAS scores were measured preoperatively and at 5 weeks, 3 months, 6 months, and 1 year postoperatively. Functional outcomes were evaluated using American Shoulder and Elbow Surgeons and Constant scores, whereas cuff integrity was assessed via MRI or ultrasonography at least 6 months postoperatively.

RESULTS

All ROM measurements, pain VAS scores, and functional scores were significantly improved regardless of the use, type, and dose of the anti-adhesive agents. In addition shoulder ROM and rotator cuff healing did not significantly differ among the groups (all n.s.).

CONCLUSIONS

No significant differences were found in the clinical and anatomical outcomes according to the type and dose of the anti-adhesive agents subacromially injected after rotator cuff repair.

LEVEL OF EVIDENCE

III.

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.

Cocktail-like gradient gelatin/hyaluronic acid bioimplant for enhancing tendon-bone healing in fatty-infiltrated rotator cuff injury models

The regeneration of enthesis tissue (native tendon-bone interface) at the post-surgically repaired rotator cuff remains a challenge for clinicians, especially with the emergence of degenerative affection such as fatty infiltration that exacerbate poor tendon-bone healing. In this study, we proposed a cocktail-like hydrogel with a four-layer structure (BMSCs+gNC@GH) for enhancing fatty infiltrated tendon-bone healing. As collagen and hyaluronic acid are the main biomacromolecules that constitute the extracellular matrix of enthesis tissue, this hydrogel was composed of UV-curable gelatin/hyaluronic acid (GelMA/HAMA) dual network gel (GH) with nanoclay (NC) and stem cells loaded. The results showed that NC exhibited a cocktail-like gradient distribution in GH, which effectively mimicked the structure of native enthesis and supported the long-term culture and encapsulation of BMSCs. What's more, the gradient variation of NC provided a biological signal for promoting gradient osteogenic differentiation of cells. Based on the in vivo results, BMSCs+gNC@GH effectively promoted fibrocartilage layer regeneration at the tendon-bone interface and inhibited fatty infiltration. Therefore, BMSCs+gNC@GH group exhibited better biomechanical properties. Thus, this cocktail-like implant may be a promising tissue-engineered scaffold for tendon-bone healing, and it provides a new idea for the development of scaffolds with the function of inhibiting degeneration.

Risk factors of tear progression in symptomatic small to medium-sized full-thickness rotator cuff tear: relationship between occupation ratio of supraspinatus and work level

BACKGROUND

Previous studies reported that full-thickness rotator cuff tear (FTRCT) is a risk factor for tear progression. However, there is no clear consensus on the risk factors of tear progression in FTRCT.

PURPOSE

To identify the demographic and radiologic risk factors of tear progression in small to medium FTRCTs.

METHODS

We retrospectively reviewed 81 shoulders of patients diagnosed with small or medium FTRCTs using magnetic resonance imaging (MRI) who underwent conservative treatment from January 2017 to November 2021. Various demographic factors, including patient work level and radiological factors such as atrophy of rotator cuff muscles were analyzed to evaluate their association with tear progression. Work level was divided into high (heavy manual labor), medium (manual labor with less activity), and low (sedentary work activity). The atrophy of rotator cuff muscles was calculated by occupation ratio.

RESULTS

Tear progression was observed in 48% (39/81) of patients (criterion for tear progression was medial-lateral or anterior-posterior tear length > 5 mm). In patients with tear progression, the lengths of medial-lateral and anterior-posterior tears progressed by 6 mm and 3 mm, respectively. Among the rotator cuff muscles, fatty degeneration and occupation ratio of the supraspinatus were only worsened (P = .014, P = 0.013, respectively). The mean MRI follow-up duration was 14.8 ± 9.0 months. The significant risk factors of tear progression were high work level (odds ratio [OR], 7.728; 95% CI, 1.204-49.610; P = .031), and occupation ratio of the supraspinatus muscle (OR, 0.308; 95% CI, 0.158-0.604; P = .001). The optimal cutoff value for the occupation ratio of the supraspinatus was 0.55 (sensitivity 74%, specificity 62%).

CONCLUSIONS

Tear progression was observed in approximately 50% of patients with symptomatic small to medium FTRCTs. High physical work level and atrophy of the supraspinatus muscle were independent risk factors of tear progression. The risk of tear progression increases with occupation ratio of the supraspinatus muscle < 0.55 and heavy manual labor.

Incidence and risk factors for early postoperative stiffness after arthroscopic rotator cuff repair in patients without preoperative stiffness

The purpose of this study was to investigate the incidence and risk factors of early postoperative stiffness in patients without preoperative stiffness undergoing isolated arthroscopic rotator cuff repair (ARCR). Two hundred seventy-four patients who underwent primary ARCR were included. At 3 months after surgery, criteria for shoulder stiffness was set as follows: (1) passive forward flexion < 120˚, or (2) external rotation at side < 30˚. Patients with preoperative stiffness or who underwent additional procedures were excluded. Patients-related, radiological (muscle atrophy and fatty infiltration), and intraoperative (tear size, repair techniques, number of anchors used, and synovitis scores) risk factors were analyzed. Univariate and multivariate analyses were used to identify risk factors for postoperative stiffness. Thirty-nine of 274 patients (14.2%) who underwent ARCR developed postoperative stiffness. Univariate analyses revealed that early postoperative stiffness was significantly associated with diabetes mellitus (p = 0.030). However, radiological and intraoperative factors did not affect postoperative shoulder stiffness (all p > 0.05). Multivariate analyses revealed early postoperative stiffness was significantly associated with diabetes mellitus and timing of rehabilitation (p = 0.024, p = 0.033, respectively). The overall incidence of early postoperative stiffness following isolated ARCR in patients without preoperative stiffness was 14.2%. Diabetes mellitus and timing of rehabilitation were independent risk factors for early postoperative stiffness following ARCR.