Abstract
Background
Onlay augmentation may enhance healing after arthroscopic rotator cuff repair (aRCR), but the optimal graft remains unclear. This study compared radiographic healing after aRCR performed without augmentation versus with acellular dermal allograft (ADA) or bioinductive collagen implant (BCI) augmentation.
Methods
This was a retrospective cohort of prospectively collected data. Patients with full-thickness rotator cuff tears who underwent aRCR between May 2021 and April 2024 were included. Tear characteristics and fatty infiltration were assessed radiographically and arthroscopically. Post-operative repair integrity was evaluated on magnetic resonance imaging obtained ≥6 months after surgery. Functional outcomes were recorded pre-operatively and at 3, 6, and 12 months.
Results
One hundred twelve patients were included (40 no augmentation, 40 BCI, 32 ADA; mean age 61 ± 9.2 years). BCI showed the highest overall healing rate (78%) versus ADA (53%) and controls (55%) (P = .049). In small-to-medium tears (no augmentation, n = 27; ADA, n = 18; BCI, n = 20), BCI demonstrated a 95% healing rate compared with ADA (72%) and controls (70%) (P = .06). Among patients with Goutallier grade ≤1, BCI was associated with significantly greater healing (85%) than ADA (64%) and controls (57%) (P = .03). On multivariable Poisson regression, BCI augmentation was independently associated with improved healing compared to no augmentation (adjusted relative risk 1.58, 95% confidence interval 1.16–2.16; P < .01). Functional outcomes did not differ among groups at any time point.
Conclusion
BCI augmentation was associated with higher healing rates, with the greatest predicted benefit observed in patients with both small-to-medium tears and minimal fatty infiltration. Healing rates were similar between ADA augmentation and no augmentation. Functional outcomes were comparable across groups.
Keywords: Rotator cuff repair, Shoulder arthroscopy, Patch augmentation, Bioinductive collagen implants, Acellular dermal allograft, Rotator cuff healing
Failure of tendon healing after arthroscopic rotator cuff repair (aRCR) is relatively common, occurring in approximately 20-90% of patients.14,15,22,27,47 Integrity of the cuff after repair is influenced by numerous factors, including the age of the patient, tear size, fatty infiltration, muscle atrophy as well as the overall biological environment at the site of the repair.22,32,36,42 Prior research has indicated that patients who sustain a retear after rotator cuff repair exhibit reduced strength and lower levels of satisfaction with their shoulder.19,21,28,48 These patients may also experience persistent pain and may require revision surgery. To mitigate the risk of rotator cuff retear and improve patient outcomes, numerous augmentation techniques have been developed to improve the overall biological and mechanical environment at the site of the repair. These augmentation techniques can be generally classified as biological, interpositional, or onlay techniques.2,3,14,15,19,39,42,45,47
Rotator cuff repair integrity correlates with clinical outcomes,6,7,23 and previous studies suggest rotator cuff augmentation can enhance outcomes and reduce retear rates after aRCR.2,3,26,33,38,39,45,49 However, selecting the optimal augmentation technique is challenging due to the diversity and abundance of unique graft options available (eg, allograft; bovine or porcine xenograft) and a lack of consensus stemming from limited comparative data. Furthermore, there is a paucity of studies comparing retear rates and outcomes between various augmentation techniques and nonaugmented controls. To our knowledge, this study is the first to directly compare 2 onlay augmentation techniques with a nonaugmented control group.
Therefore, the primary objective of this study was to compare radiographic healing rates after aRCR among 3 cohorts of patients: a no augmentation group; augmentation with an onlay, bioinductive collagen implant (BCI); and augmentation with an onlay, structural, acellular dermal allograft (ADA). The secondary objective of this study was to compare functional outcomes among the 3 groups. Our hypothesis was that the retear rates after aRCR with BCI or ADA augmentation would be significantly lower than those without augmentation. Furthermore, it was hypothesized that there would be no significant difference in retear rates between aRCR with BCI versus ADA augmentation. Finally, we hypothesized that there would be no significant differences in functional outcomes at final follow-up among the 3 groups.
Materials and methods
Study design and patient selection
We performed a retrospective cohort study of prospectively collected data of patients with symptomatic, full-thickness rotator cuff tears who underwent aRCR at a single, academic, tertiary-referral center in an urban setting between May 2021 to April 2024. Institutional review board approval was obtained. Inclusion criteria consisted of patients ≥18 years of age with a full-thickness posterosuperior rotator cuff tear, aRCR using a transosseous-equivalent double-row repair construct, primary repair, magnetic resonance imaging (MRI) available for review pre-operatively as well as at or beyond six months post-operatively, and functional outcomes available for analysis. Exclusion criteria consisted of patients younger than 18 years of age, partial-thickness tears, open and/or revision rotator cuff repair, single-row constructs, patients who did not obtain an MRI of their operative shoulder at or beyond 6 months post-operatively, subscapularis tears requiring surgical fixation. All surgeries were performed by a group of 6 fellowship trained sports medicine or shoulder and elbow orthopedic surgeons.
For analysis, patients were grouped based on treatment technique into the following cohorts: no augmentation control; BCI; or ADA. The decision to utilize augmentation (BCI or ADA) versus no augmentation was made at the discretion of the treating surgeon based on intraoperative assessment of tear size, tissue quality, chronicity, and perceived healing potential. No standardized treatment algorithm or predefined indications were used to guide augmentation selection. Baseline patient characteristics, medical comorbidities, and demographic data were collected on all patients. These data include age, sex, laterality, smoking status, body mass index (BMI), presence of diabetes, worker's compensation status, and chronicity of the tear (ie, acute versus chronic). Tears were classified as acute when associated with a discrete traumatic onset and as chronic in the absence of an identifiable traumatic event. These data were collected prospectively and reviewed retrospectively; any missing data was queried through the electronic medical record.
Surgical technique and rehabilitation
All patients underwent aRCR using a transosseous-equivalent, double-row repair construct. All procedures were performed under general anesthesia in the beach-chair position. During the diagnostic arthroscopy, the long head of the biceps tendon was evaluated for pathology, and if found, either an arthroscopic or mini-open biceps tenodesis was performed. Subacromial decompression was performed across the entire study population. The size of the tear was assessed arthroscopically and classified using the Cofield classification.17 During the repair, the number of anchors utilized in the medial and lateral rows was variable and dependent upon tear size and morphology. Standard releases were performed as indicated for the large and massive tears and all repairs were completed with the goal of achieving a tension-free repair.
The REGENETEN patch (Smith & Nephew, Memphis, TN, USA) was employed in all cases of BCI augmentation (Fig. 1). REGENETEN is a bioinductive collagen scaffold derived from purified bovine Achilles tendon comprised of type-1 collagen. After completion of the lateral row, the implant inserter was placed through the lateral portal. The implant was deployed and placed directly onto the site of the rotator cuff repair. Bioabsorbable tendon staples were placed to secure the implant directly to the rotator cuff tendon. Finally, the implant is secured to the greater tuberosity laterally using polyether ether ketone staples, completing the augmentation.
Figure 1.
Intraoperative arthroscopic image demonstrating the final repair construct after application of the acellular dermal allograft.
Dermis on Demand (DePuy Mitek, Raynham, MA, USA) was utilized in all cases of ADA augmentation (Fig. 2). Dermis on Demand is a human ADA that serves as a mechanical scaffold and may provide a biologically favorable environment for tissue integration.31 Unlike BCI augmentation, ADA augmentation was performed after the placement of the medial row anchors. Suture limbs from the medial row anchors were threaded through the grafts, resulting in the application of 3 to 4 Dermis on Demand grafts across the repair site. These suture limbs from the medial row were subsequently incorporate into the lateral row anchors, completing the repair.
Figure 2.
Intraoperative arthroscopic images demonstrating the introduction and securing of the bioinductive collagen implant on top of the double-row repair.
Post-operatively, patients were placed in a shoulder sling with abduction pillow. In the immediate post-operative period, patients were advised to avoid lifting objects heavier than 5 pounds. Patients were instructed to use their sling for 4 weeks. They were allowed to remove their sling to only for hygiene and to perform gentle hand, wrist, elbow, and pendulum exercises. At 4 weeks, use of the sling was discontinued, and patients were instructed to begin passive range of motion of the shoulder with a physical therapist. By 8 weeks, patients progressed to active-assisted range of motion. Finally, at 12 weeks after surgery, patients were allowed to begin strengthening exercises. Return to unrestricted shoulder activity was allowed at 5 months in all patients.
Radiographic assessment
MRIs were performed without contrast and were reviewed by an independent musculoskeletal radiologist as well as the attending surgeon. Disagreements were resolved by consensus. The pre-operative MRI was used to confirm the diagnosis of a rotator cuff tear. On pre-operative MRI, the degree of fatty infiltration of the rotator cuff musculature was evaluated using the Fuchs et al18 modification of the Goutallier classification.20 In cases involving multiple tendons, the highest/worst grade among the involved tendons was used for analysis. Accordingly, patients classified as Goutallier grade ≤1 had no tendon demonstrating greater than grade 1 fatty infiltration. Using the Sugaya classification,41 post-operative repair integrity was assessed. Sugaya types I–III, including partial-thickness defects (type III), were considered intact repairs, whereas types IV and V were considered not healed or retorn.14
Functional outcome assessment
Functional outcomes were assessed pre-operatively and post-operatively at 3 months, 6 months, and ≥1 year using the Single Assessment Numeric Evaluation (SANE), American Shoulder and Elbow Surgeons (ASES), and visual analog scale (VAS) scores. The functional outcomes were gathered utilizing proprietary software (OBERD, Columbia, MO, USA), either on-site at post-operative follow-up appointments utilizing an encrypted device or remotely on the patient's personal device. Credentialed research assistants reconciled any incomplete or missing functional outcomes through direct telephone communication.
Statistical analysis
Descriptive statistics were calculated for all variables. Differences between groups were assessed using chi-square tests for categorical variables and one-way analysis of variance or Kruskal-Wallis tests for continuous variables. Unadjusted healing rates were compared using Fisher exact tests and pairwise z-tests, with results reported as relative risks (RRs) and 95% confidence intervals (95% CIs). Stratified analyses were performed based on tear size (small/medium vs. large/massive) and Goutallier grade (0–1 vs. ≥2). Subgroup analyses were exploratory, and no formal adjustment for multiple comparisons was performed. A multivariable Poisson regression model with robust standard errors was used to estimate adjusted relative risks (aRRs) for rotator cuff healing, controlling for age, sex, BMI, tear size, smoking status, Goutallier grade, worker's compensation status, diabetes, and tear chronicity. Covariates were selected a priori based on known clinical associations with rotator cuff healing. Given the sample size, the model was constructed to remain parsimonious while accounting for key potential confounders. Model-derived predicted probabilities of healing were calculated for each treatment group and are presented as marginal effects heatmaps to illustrate differences in expected healing across combinations of tear size and fatty infiltration. All statistical analyses were performed using R statistical software (version 4.3.1; The R Foundation for Statistical Computing). Statistical significance was defined as P < .05.
Results
Patients demographics
All patients who met eligibility criteria were included in the analysis. Therefore, there were 112 patients who were ultimately included. Forty patients did not receive augmentation, 32 patients underwent aRCR with ADA augmentation, and 40 patients underwent aRCR with BCI augmentation. Patient demographics and tear characteristics are outlined in Table I. Notably, there were no significant differences among the 3 cohorts except for mean age (58.4 ± 9.5 years [no augmentation]; 66 ± 5.8 years [ADA]; 59.5 ± 9.5 years [BCI]; P < .01) and BMI (31.7 ± 8 kg/m2 [no augmentation]; 30.8 ± 6.3 kg/m2 [ADA]; 28.1 ± 3.4 kg/m2 [BCI]; P = .03) at the time of surgery. Of note, MRIs were obtained at a mean of 9.3 months post-operatively (range, 6-50.3 months) for the entire study population. The mean MRI follow-up was 10.8 months in the no augmentation group, 8.7 months in the ADA group, and 8.3 months in the BCI group (overall mean 9.3 months), with no significant difference among the groups (P = .276).
Table I.
Patient pre-operative characteristics.
| Characteristic | No augment (n = 40) | ADA (n = 32) | BCI (n = 40) | P value |
|---|---|---|---|---|
| Age (yr)∗ | 58.4 (9.5) | 66 (5.8) | 59.5 (9.5) | <.01 |
| Sex (females)† | 20 (50) | 19 (59.4) | 18 (45) | .48 |
| Smoking† | 3 (7.5) | 4 (12.5) | 4 (10) | .78 |
| BMI (kg/m2)∗ | 31.7 (8) | 30.8 (6.3) | 28.1 (3.4) | .03 |
| Diabetes mellitus† | 8 (20) | 8 (25) | 3 (7.5) | .12 |
| Workers compensation† | 7 (17.5) | 3 (9.4) | 6 (15) | .61 |
| Acute tear† | 5 (12.5) | 7 (21.9) | 6 (15) | .55 |
| Goutallier ≤1† | 37 (92.5) | 25 (78.1) | 34 (85) | .22 |
| Tear size, small/medium† | 27 (67.5) | 18 (56.3) | 20 (50) | .28 |
ADA, acellular dermal allograft; BCI, bioinductive collagen implant; BMI, body mass index; ANOVA, analysis of variance.
Continuous variables were compared using one-way ANOVA and categorical variables were compared using chi-square tests. P values <.05 are indicated in bold italics.
Continuous variables reported as the mean (standard deviation).
Categorical variables reported as the number of patients (percentage).
Radiographic outcomes
The healing rate for the entire study population was 62.5%. The healing rates for each cohort are outlined in Table II. The number of patients with an intact repair at final radiographic follow-up were 22 (55%), 17 (53%), and 31 (78%) in the no augmentation, ADA augmentation, and BCI augmentation cohorts, respectively (P = .049). When compared to the no augmentation group, ADA augmentation did not have a significant difference in healing at final radiographic follow-up (RR 1.04, 95% CI 0.67-1.59, P = .87). However, BCI augmentation had a significantly higher rate of healing when compared to both the no augmentation (RR 1.41, 95% CI 1.02-1.95, P = .03) and ADA cohorts (RR 1.46, 95% CI 1.01-2.10, P = .03).
Table II.
Healing rate after arthroscopic rotator cuff repair on magnetic resonance imaging ≥6 mo post-operatively.
| Augmentation | Healed, no. (%) | Retear, no. (%) | P value | NA vs. ADA |
NA vs. BCI |
ADA vs. BCI |
|||
|---|---|---|---|---|---|---|---|---|---|
| RR | 95% CI | RR | 95% CI | RR | 95% CI | ||||
| NA | 22 (55) | 18 (45) | .049 | 1.04 | 0.67-1.59 | 1.41 | 1.02-1.95 | 1.46 | 1.01-2.0 |
| ADA | 17 (53.1) | 15 (46.9) | |||||||
| BCI | 31 (77.5) | 9 (22.5) | |||||||
NA, no augmentation; ADA, acellular dermal allograft; BCI, bioinductive collagen implant; RR, relative risk; 95% CI, 95% confidence interval.
Categorical variables were compared using chi-square tests.
P values <.05 are indicated in bold italics.
Healing rates in small/medium tears
Among patients with small- and medium-sized tears (no augmentation, n = 27; ADA, n = 18; BCI, n = 20), healing rates varied by treatment group (Table III). The BCI cohort demonstrated the highest rate of intact repairs at 95%, followed by the ADA augmentation cohort at 72%, and the no augmentation cohort at 67%. Overall, this difference approached statistical significance (P = .06). When compared to no augmentation, the rate of healing in the BCI augmentation cohort was significantly more likely (RR 1.43, 95% CI 1.07-1.89, P = .02). When comparing BCI to ADA augmentation, there was a trend toward significance (RR 1.32, 95% CI 0.97-1.78, P = .06). Finally, no significant difference was observed between the ADA and no augmentation groups (RR 0.92, 95% CI 0.62-1.37, P = .69).
Table III.
Healing rate after arthroscopic rotator cuff repair on magnetic resonance imaging ≥6 mo post-operatively, stratified by rotator cuff tear size.
| Small/medium tears | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Healed, no. (%) | Retear, no. (%) | P value | NA vs. ADA |
NA vs. BCI |
ADA vs. BCI |
||||
| RR | 95% CI | RR | 95% CI | RR | 95% CI | ||||
| NA | 18 (66.7) | 9 (33.3) | .06 | 0.92 | 0.62-1.37 | 1.43 | 1.07-1.89 | 1.32 | 0.97-1.78 |
| ADA | 13 (72.2) | 5 (27.8) | |||||||
| BCI | 19 (95) | 1 (5) | |||||||
| Large/massive tears | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Healed, no. (%) | Retear, no. (%) | P value | NA vs. ADA |
NA vs. BCI |
ADA vs. BCI |
||||
| RR | 95% CI | RR | 95% CI | RR | 95% CI | ||||
| NA | 4 (30.8) | 9 (69.2) | .11 | 1.08 | 0.34-3.44 | 1.95 | 0.80-4.75 | 2.1 | 0.85-5.18 |
| ADA | 4 (28.6) | 10 (71.4) | |||||||
| BCI | 12 (60) | 8 (40) | |||||||
NA, no augmentation; ADA, acellular dermal allograft; BCI, bioinductive collagen implant; RR, relative risk; 95% CI, 95% confidence interval.
Categorical variables were compared using chi-square tests.
Healing rate in large/massive tears
Among patients with large- and massive-sized tears (no augmentation, n = 13; ADA, n = 14; BCI, n = 20), healing rates varied by treatment group in favor of BCI augmentation (31% no augmentation, 29% ADA augmentation, 60% BCI augmentation, P = .11). However, this did not reach statistical significance. While not statistically significant, BCI augmentation demonstrated a higher likelihood of healing compared to the ADA augmentation (RR 2.10, 95% CI: 0.85–5.18, P = .09) and no augmentation (RR 1.95, 95% CI: 0.80–4.75, P = .16) cohorts.
Healing rates based on fatty infiltration
Table IV compares the healing rate among the 3 cohorts when stratifying by pre-operative Goutallier grades. Among patients with pre-operative Goutallier grades ≤1, there was a significant difference in healing rates among the 3 cohorts in favor of BCI augmentation (57% no augmentation, 64% ADA augmentation, 85% BCI augmentation, P = .03). When compared to no augmentation, BCI augmentation was associated with a significantly higher rate of healing (RR 1.50, 95% CI 1.10-2.06, P = .01). There was a trend toward significance when comparing BCI augmentation to ADA augmentation (RR 1.33, 95% CI 0.96-1.85, P = .07). There was no significant difference when comparing ADA augmentation to no augmentation (RR 1.13, 95% CI 0.75-1.69, P = .61). Among patients with pre-operative Goutallier scores ≥2, healing rates were low across all groups and did not significantly differ (33.3% no augmentation, 14.3% ADA augmentation, and 33.3% BCI augmentation, P = .68).
Table IV.
Healing rate after arthroscopic rotator cuff repair on magnetic resonance imaging ≥6 mo post-operatively, stratified by the amount of fatty infiltration.
| Goutallier 0-1 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Healed, no. (%) | Retear, no. (%) | P value | NA vs. ADA |
NA vs. BCI |
ADA vs. BCI |
||||
| RR | 95% CI | RR | 95% CI | RR | 95% CI | ||||
| NA | 21 (56.8) | 16 (43.2) | .03 | 1.13 | 0.75-1.69 | 1.50 | 1.10-2.06 | 1.33 | 0.96-1.85 |
| ADA | 16 (64) | 9 (36) | |||||||
| BCI | 29 (85.3) | 5 (14.7) | |||||||
| Goutallier 2-4 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Healed, no. (%) | Retear, no. (%) | P value | NA vs. ADA |
NA vs. BCI |
ADA vs. BCI |
||||
| RR | 95% CI | RR | 95% CI | RR | 95% CI | ||||
| NA | 1 (33.3) | 2 (66.7) | .68 | 0.43 | 0.04-4.82 | 1 | 0.14-7.10 | 2.33 | 0.27-19.8 |
| ADA | 1 (14.3) | 6 (85.7) | |||||||
| BCI | 2 (33.3) | 4 (66.7) | |||||||
NA, no augmentation; ADA, acellular dermal allograft; BCI, bioinductive collagen implant. RR, relative risk; 95% CI, 95% confidence interval.
Fatty infiltration was assessed using the Fuchs modification of the Goutallier classification. Categorical variables were compared with chi-square tests. P values <.05 are indicated in bold italics.
Multivariable regression analysis
We performed a multivariable Poisson regression, adjusting for patient age, sex, BMI, tear size, smoking status, Goutallier grade, worker's compensation status, diabetes, and tear chronicity (Table V). BCI augmentation was associated with significantly higher rates of healing when compared to the no augmentation group (aRR 1.58, 95% CI: 1.16–2.16, P < .01). However, there was no significant difference between BCI and ADA augmentation (aRR 1.32, 95% CI: 0.88–1.96, P = .18) and between ADA augmentation and no augmentation (aRR 1.20, 95% CI: 0.80–1.81, P = .38).
Table V.
Adjusted relative risk (aRR) after adjusting for potential confounding variables using a multivariable Poisson regression model.
| Comparison | aRR | 95% CI | P value |
|---|---|---|---|
| ADA vs. NA | 1.20 | 0.80-1.81 | .38 |
| BCI vs. NA | 1.58 | 1.16-2.16 | <.01 |
| BCI vs. ADA | 1.32 | 0.88-1.96 | .18 |
CI, confidence interval; ADA, acellular dermal allograft; NA, no augmentation; BCI, bioinductive collagen implant; aRR, adjusted relative risk.
P value <.05 is indicated in bold italics.
Model-derived predicted probabilities are presented in Figure 3 to illustrate the interaction between tear size, fatty infiltration, and treatment group. These probabilities suggested higher healing with BCI augmentation compared to both ADA augmentation and no augmentation across all combinations. However, this effect was most pronounced for small or medium-sized tears with a Goutallier grade ≤1 (0.90 healing probability BCI, 0.68 healing probability ADA, 0.57 healing probability NA) suggesting that the relative benefit of BCI augmentation may be the greatest in patients with small-to-medium tears and minimal fatty infiltration.
Figure 3.
Predicted probability of rotator cuff healing derived from multivariable Poisson regression, stratified by tear size (small/medium vs. large/massive) and Goutallier grade (0–1 vs. ≥ 2). Each panel represents a treatment group. Color intensity represents the probability of healing, with higher values shown in blue and lower values in purple. BCI, bioinductive collagen implant; ADA, acellular dermal allograft.
Functional outcomes and reoperations
All 3 cohorts saw improvements in SANE, ASES, and VAS scores (Table VI). These improvements were largely maintained at each time point throughout the post-operative course. When comparing functional outcomes among the 3 patient cohorts, there were no significant differences in VAS, ASES, or SANE scores pre-operatively or at the 3 month, 6 month, and ≥1 year follow-up visits. Reoperation rates were low across all groups. One patient (2.5%) in the no augmentation group underwent repeat arthroscopy with débridement and lysis of adhesions for adhesive capsulitis. Two patients (6.3%) in the ADA group and 1 patient (2.5%) in the BCI group underwent conversion to reverse shoulder arthroplasty for progression to cuff tear arthropathy.
Table VI.
Patient-reported functional outcomes, reported as mean ± standard deviation.
| SANE | ||||
|---|---|---|---|---|
| Control | ADA | BCI | P value | |
| Pre-operative | 36.5 ± 22.8 | 32.1 ± 19.6 | 30.8 ± 19.9 | .51 |
| 3 mo | 56.1 ± 23.3 | 66 ± 16.8 | 56.3 ± 18.8 | .25 |
| 6 mo | 80 ± 20.2 | 76.4 ± 21.4 | 73 ± 24.4 | .66 |
| 1 yr | 75.8 ± 27.5 | 84.8 ± 19.5 | 73.5 ± 23.4 | .24 |
| ASES | ||||
|---|---|---|---|---|
| Control | ADA | BCI | P value | |
| Pre-operative | 40.5 ± 18.9 | 44.1 ± 17.5 | 42.8 ± 16.7 | .74 |
| 3 mo | 56.6 ± 20.5 | 69.4 ± 19.4 | 66.3 ± 21.9 | .11 |
| 6 mo | 82 ± 14.8 | 88.5 ± 12.8 | 79 ± 14.2 | .15 |
| 1 yr | 82.6 ± 21 | 82.1 ± 22.2 | 76.7 ± 21 | .50 |
| VAS | ||||
|---|---|---|---|---|
| Control | ADA | BCI | P value | |
| Pre-operative | 6.1 ± 4 | 5.1 ± 2.4 | 5.3 ± 2.4 | .45 |
| 3 mo | 2.6 ± 1.9 | 1.8 ± 2.3 | 2.4 ± 2.4 | .54 |
| 6 mo | 1.7 ± 2.5 | 0.82 ± 1.3 | 3.0 ± 5.5 | .23 |
| 1 yr | 1.8 ± 2.5 | 2.3 ± 3.0 | 2.3 ± 2.6 | .68 |
SANE, Single Assessment Numeric Evaluation; ASES, American Shoulder and Elbow Surgeons score; VAS, visual analog scale; ADA, acellular dermal allograft; BCI, bioinductive collagen implant.
Discussion
This study evaluated healing rates and patient-reported outcomes among patients undergoing aRCR using no augmentation, ADA, or BCI. Post-operative MRI assessments showed higher healing rates in the BCI group compared with the ADA and nonaugmented groups. This finding remained consistent after multivariable adjustment for known predictors of healing, including age, BMI, tear size, and fatty infiltration, suggesting an independent association between BCI augmentation and improved healing. Based on our model-derived predicted probabilities, the greatest predicted benefit of BCI was observed in patients with small-to-medium sized tears and minimal fatty infiltration. Importantly, the primary analysis of the overall cohort demonstrated a significant difference in healing among treatment groups, whereas subgroup analyses were intended to be exploratory and to provide a clinically relevant stratified interpretation. Despite improved healing, no significant differences in patient-reported outcomes were observed at short-term follow-up. Furthermore, although there was a difference in the duration of radiographic follow-up among the 3 groups, this difference was not statistically significant, and all patients had at least 6 months of radiographic follow-up. A majority of retears occur within 6 months post-operatively,24,46 which may mitigate the impact of this difference.
There are several available augmentation grafts which have different strategies to promote rotator cuff healing with both ADAs and bovine collagen-based implants commonly utilized. Studies have identified theoretical benefits of the application of ADA as an onlay augment. Once applied, the ADA augment serves as a scaffold for tenocyte migration. Kim et al30 demonstrated the potential for cellular infiltration with neo-tendon formation in a rabbit model utilizing ADA in rotator cuff repair. Biomechanical and cadaveric studies have shown that ADA augmentation leads to an increased maximum load to failure and pullout strength.4,5,30 Omae et al34 found that ADA improved these properties without increasing the stiffness of the construct. In theory, ADA augmentation has biological properties to enhance healing at the enthesis in addition to biomechanical benefits to improve repair integrity.
Proponents of the use of BCI augmentation in rotator cuff repair cite the proposed benefits of improved healing environment, mechanical support, bioinductive potential, and reduced retear rate.10 Initially, the collagen augmentation acts to potentially reducing gap formation and early failure by reducing strain.8,40 The BCI is made of purified bovine type-1 collagen with a porous structure which facilitates cellular infiltration, angiogenesis, and tissue integration as supported by histologic studies.1,9,12 Therefore, over time, collagen develops in an organized formation, improving biomechanical strength. Jung et al25 found a greater maximum load to failure in repairs augmented with bovine collagen patches in a cadaveric sheep model. Potential concerns with the use of BCI possible inflammatory reactions leading to bursal-sided swelling.11
The overall retear rate of patients augmented with BCI was 22.5%. After multivariable adjustment, BCI augmentation was associated with a higher relative likelihood of healing than no augmentation. This is consistent with prior studies which have demonstrated improved healing rates with BCI augmentation. Bushnell et al11 reported favorable radiographic outcomes of full-thickness rotator cuff tears with a minimum of 2-year follow-up with 11.5% retear rate for medium-sized tears and a 17.1% retear rate for large-sized tears. Similarly, Thon et al44 demonstrated a healing rate of 96% in large and massive-sized tears when using BCI augmentation. Of note, neither study had a comparative group. Across 12 studies utilizing BCI augmentation, a systematic review found improved patient outcomes scores, many approaching the minimal clinically important difference, with improved tendon thickness and identified an overall retear rates of 8.3% for full thickness tears, with retear rate ranging from 0% to 21%.45 Therefore, similarly to ADA, BCI appears to enhance the healing potential of rotator cuff repairs.
While several prior investigations have evaluated outcomes of rotator cuff augmentation, many lack a control group making it challenging to interpret the significance of the reported clinical improvements. Furthermore, there are no existing studies directly comparing BCI and ADA augmentation. In the current study, BCI augmentation demonstrated numerically higher healing rates than ADA augmentation; however, this difference did not reach statistical significance after multivariable adjustment. Model-derived predicted probabilities suggested that the greatest relative benefit of BCI augmentation may occur in patients with small-to-medium tears and minimal fatty infiltration. There are several potential underlying properties of the BCI that may predict improved healing rates compared to ADA. BCI augmentation has been reported to promote tendon differentiation and is replaced by tendon-like tissue, whereas ADA has been described primarily as a structural scaffold with less bioactivity.12,13 BCI augmentation has also been reported to increase tendon thickness.37
Based on our multivariable regression analyses, the use of BCI augmentation may be associated with improved healing after aRCR in selected patients. Model-derived predicted probabilities suggested that the greatest healing benefit with BCI was observed in patients with both small-to-medium tears and minimal fatty infiltration. The observed trends toward improved healing in small-to-medium tears and minimal fatty degeneration may help inform patient selection and surgical decision-making for BCI augmentation.
While BCI augmentation was associated with improved radiographic healing, no differences in short-term functional outcomes were observed. The clinical significance of improved structural healing remains an area of ongoing investigation as prior studies have demonstrated similar findings.16,37 Structural integrity and short-term functional outcomes are not always directly correlated after rotator cuff repair, particularly within the first post-operative year. It is possible that differences in clinical outcomes associated with improved tendon healing may become more apparent with longer-term follow-up. Additionally, augmentation techniques are associated with an increased “upfront” cost.35 Therefore, the value of these interventions should be evaluated in the context of long-term outcomes. Future studies are needed to assess the cost-effectiveness and long-term clinical impact of these techniques.
Limitations
The radiographic assessment of rotator cuff healing was performed at a minimum of 6 months post-operatively, which is sufficient to capture early retears but does not account for potential attritional failures over time. The broad range of post-operative MRI timing may have introduced heterogeneity in healing assessment, as later imaging may capture attritional failures not present at earlier time points. Longer-term follow-up is needed to evaluate durability of healing following augmentation. Second, treatment allocation was based on surgeon discretion without predefined indications, introducing the possibility of confounding by indication. Although multivariable adjustment was performed for known predictors of rotator cuff healing, residual selection bias cannot be excluded. Third, tendon thickness was not consistently evaluated on post-operative MRI and therefore was not included in the analysis. Although prior studies have examined tendon thickness following rotator cuff repair, its relationship with clinical outcomes remains unclear, with several studies demonstrating no consistent correlation between tendon thickness and functional outcomes.29,43 Fourth, subgroup analyses based on tear size and fatty infiltration were limited by sample size and may be underpowered to detect differences between treatment groups. This may explain the lack of statistical significance observed in certain subgroup comparisons despite observed trends favoring BCI augmentation. Fifth, while our primary analysis revealed a statistically significant difference in healing among the 3 groups, the limited sample size may restrict the accuracy of the estimated effect size and reduce the ability to identify smaller differences in subgroup analyses.
Finally, while healing rates were improved when comparing patients with BCI augmentation versus ADA augmentation, that difference did not reach statistical significance introducing the possibility of a Type II error.
Conclusion
In this retrospective cohort study, BCI augmentation was associated with higher post-operative healing rates following aRCR. Model-derived probability analyses suggested that the greatest potential benefit of BCI augmentation may occur in patients with small-to-medium tears and minimal fatty infiltration. Functional outcomes were comparable among the 3 groups at short-term follow-up. Given the retrospective design and potential for residual selection bias, prospective comparative studies are needed to further define the indications and clinical utility of BCI augmentation.
Disclaimers:
Funding: No funding was disclosed by the authors.
Conflicts of interest: Robert J. Gillespie reports the following relationships relevant to this submission: Aevumed (stock option), Collamedix (stock option), Shoulder Innovations Inc. (other professional activities), and service on the American Shoulder and Elbow Surgeons (ASES) Fellowship Committee as Co-Chair (Board of Directors/Committee Member; Self). Any additional authors, their immediate families, and any research foundations with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.
Footnotes
This study was approved by the SpartaIRB (STUDY20210669) on May 18, 2021.
References
- 1.Arnoczky S.P., Bishai S.K., Schofield B., Sigman S., Bushnell B.D., Hommen J.P., et al. Histologic evaluation of Biopsy specimens obtained after Rotator Cuff Repair augmented with a highly porous collagen implant. Arthroscopy. 2017;33:278–283. doi: 10.1016/j.arthro.2016.06.047. [DOI] [PubMed] [Google Scholar]
- 2.Avanzi P., Giudici L., Capone A., Cardoni G., Lunardi G., Foti G., et al. Prospective randomized controlled trial for patch augmentation in rotator cuff repair: 24-month outcomes. J Shoulder Elbow Surg. 2019;28:1918–1927. doi: 10.1016/j.jse.2019.05.043. [DOI] [PubMed] [Google Scholar]
- 3.Barber F.A., Burns J.P., Deutsch A., Labbé M.R., Litchfield R.B. A prospective, randomized evaluation of acellular human dermal matrix augmentation for arthroscopic rotator cuff repair. Arthroscopy. 2012;28:8–15. doi: 10.1016/j.arthro.2011.06.038. [DOI] [PubMed] [Google Scholar]
- 4.Barber F.A., Herbert M.A., Coons D.A. Tendon augmentation grafts: biomechanical failure loads and failure patterns. Arthroscopy. 2006;22:534–538. doi: 10.1016/j.arthro.2005.12.021. [DOI] [PubMed] [Google Scholar]
- 5.Beitzel K., Chowaniec D.M., McCarthy M.B., Cote M.P., Russell R.P., Obopilwe E., et al. Stability of double-row rotator cuff repair is not adversely affected by scaffold interposition between tendon and bone. Am J Sports Med. 2012;40:1148–1154. doi: 10.1177/0363546512437835. [DOI] [PubMed] [Google Scholar]
- 6.Bishop J., Klepps S., Lo I.K., Bird J., Gladstone J.N., Flatow E.L. Cuff integrity after arthroscopic versus open rotator cuff repair: a prospective study. J Shoulder Elbow Surg. 2006;15:290–299. doi: 10.1016/j.jse.2005.09.017. [DOI] [PubMed] [Google Scholar]
- 7.Boileau P., Brassart N., Watkinson D.J., Carles M., Hatzidakis A.M., Krishnan S.G. Arthroscopic repair of full-thickness tears of the supraspinatus: does the tendon really heal? J Bone Joint Surg Am. 2005;87:1229–1240. doi: 10.2106/JBJS.D.02035. [DOI] [PubMed] [Google Scholar]
- 8.Burkhead W.Z., Schiffern S.C., Krishnan S.G. Use of graft jacket as an augmentation for massive rotator Cuff tears. Semin Arthroplasty. 2007;18:11–18. doi: 10.1053/j.sart.2006.11.017. [DOI] [Google Scholar]
- 9.Bushnell B.D., Bishai S.K., Krupp R.J., McMillan S., Schofield B.A., Trenhaile S.W., et al. Treatment of partial-thickness Rotator Cuff tears with a resorbable bioinductive Bovine Collagen implant: 1-Year results from a prospective multicenter registry. Orthop J Sports Med. 2021;9 doi: 10.1177/23259671211027850. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Bushnell B.D., Connor P.M., Harris H.W., Ho C.P., Trenhaile S.W., Abrams J.S. Retear rates and clinical outcomes at 1 year after repair of full-thickness rotator cuff tears augmented with a bioinductive collagen implant: a prospective multicenter study. JSES Int. 2021;5:228–237. doi: 10.1016/j.jseint.2020.10.020. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Bushnell B.D., Connor P.M., Harris H.W., Ho C.P., Trenhaile S.W., Abrams J.S. Two-year outcomes with a bioinductive collagen implant used in augmentation of arthroscopic repair of full-thickness rotator cuff tears: final results of a prospective multicenter study. J Shoulder Elbow Surg. 2022;31:2532–2541. doi: 10.1016/j.jse.2022.05.025. [DOI] [PubMed] [Google Scholar]
- 12.Camacho-Chacon J.A., Cuenca-Espierrez J., Roda-Rojo V., Martin-Martinez A., Calderon-Meza J.M., Alvarez-Alegret R., et al. Bioinductive collagen implants facilitate tendon regeneration in rotator cuff tears. J Exp Orthop. 2022;9:53. doi: 10.1186/s40634-022-00495-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Chen P., Wang A., Haynes W., Landao-Bassonga E., Lee C., Ruan R., et al. A bio-inductive collagen scaffold that supports human primary tendon-derived cell growth for rotator cuff repair. J Orthop Translat. 2021;31:91–101. doi: 10.1016/j.jot.2021.10.006. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Cole B.J., Kaiser J.T., Wagner K.R., Sivasundaram L., Otte R.S., Tauro T.M., et al. Prospective randomized trial of biologic augmentation with bone marrow aspirate concentrate in patients undergoing arthroscopic Rotator Cuff Repair. Am J Sports Med. 2023;51:1234–1242. doi: 10.1177/03635465231154601. [DOI] [PubMed] [Google Scholar]
- 15.Collin P., Abdullah A., Kherad O., Gain S., Denard P.J., Lädermann A. Prospective evaluation of clinical and radiologic factors predicting return to activity within 6 months after arthroscopic rotator cuff repair. J Shoulder Elbow Surg. 2015;24:439–445. doi: 10.1016/j.jse.2014.08.014. [DOI] [PubMed] [Google Scholar]
- 16.Dagher D., Shah D., Kruse C., Abdel Khalik H., Saleh U., Hachem A.-I., et al. Structural augmentation in Rotator Cuff Repair decreases the risk of retear: a systematic review and meta-analysis. Am J Sports Med. 2026;18 doi: 10.1177/03635465251400356. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.DeOrio J.K., Cofield R.H. Results of a second attempt at surgical repair of a failed initial rotator-cuff repair. J Bone Joint Surg Am. 1984;66:563–567. [PubMed] [Google Scholar]
- 18.Fuchs B., Weishaupt D., Zanetti M., Hodler J., Gerber C. Fatty degeneration of the muscles of the rotator cuff: assessment by computed tomography versus magnetic resonance imaging. J Shoulder Elbow Surg. 1999;8:599–605. doi: 10.1016/s1058-2746(99)90097-6. [DOI] [PubMed] [Google Scholar]
- 19.Galatz L.M., Ball C.M., Teefey S.A., Middleton W.D., Yamaguchi K. The outcome and repair integrity of completely arthroscopically repaired large and massive rotator cuff tears. J Bone Joint Surg Am. 2004;86:219–224. doi: 10.2106/00004623-200402000-00002. [DOI] [PubMed] [Google Scholar]
- 20.Goutallier D., Postel J.M., Bernageau J., Lavau L., Voisin M.C. Fatty muscle degeneration in cuff ruptures. Pre- and postoperative evaluation by CT scan. Clin Orthop Relat Res. 1994;304:78–83. [PubMed] [Google Scholar]
- 21.Harryman D.T., Mack L.A., Wang K.Y., Jackins S.E., Richardson M.L., Matsen F.A. Repairs of the rotator cuff. Correlation of functional results with integrity of the cuff. J Bone Joint Surg Am. 1991;73:982–989. [PubMed] [Google Scholar]
- 22.Hoffmeister T.M., Denard P.J., Tashjian R.Z., Sethi P.M. Augmentation techniques for Rotator Cuff repairs. JBJS Rev. 2025;13 doi: 10.2106/JBJS.RVW.25.00007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Huijsmans P.E., Pritchard M.P., Berghs B.M., van Rooyen K.S., Wallace A.L., de Beer J.F. Arthroscopic rotator cuff repair with double-row fixation. J Bone Joint Surg Am. 2007;89:1248–1257. doi: 10.2106/JBJS.E.00743. [DOI] [PubMed] [Google Scholar]
- 24.Iannotti J.P., Deutsch A., Green A., Rudicel S., Christensen J., Marraffino S., et al. Time to failure after rotator cuff repair: a prospective imaging study. J Bone Joint Surg Am. 2013;95:965–971. doi: 10.2106/JBJS.L.00708. [DOI] [PubMed] [Google Scholar]
- 25.Jung C., Spreiter G., Audigé L., Ferguson S.J., Flury M. Patch-augmented rotator cuff repair: influence of the patch fixation technique on primary biomechanical stability. Arch Orthop Trauma Surg. 2016;136:609–616. doi: 10.1007/s00402-016-2436-6. [DOI] [PubMed] [Google Scholar]
- 26.Kantanavar R., Lee I.E., Rhee S.M., Rhee Y.G. Outcomes of arthroscopic single-row repair alone vs. repair with human dermal allograft patch augmentation in patients with large to massive, posterosuperior rotator cuff tears: a retrospective comparative study. J Shoulder Elbow Surg. 2024;33:823–831. doi: 10.1016/j.jse.2023.08.002. [DOI] [PubMed] [Google Scholar]
- 27.Keener J.D., Galatz L.M., Stobbs-Cucchi G., Patton R., Yamaguchi K. Rehabilitation following arthroscopic rotator cuff repair: a prospective randomized trial of immobilization compared with early motion. J Bone Joint Surg Am. 2014;96:11–19. doi: 10.2106/JBJS.M.00034. [DOI] [PubMed] [Google Scholar]
- 28.Kim H.M., Caldwell J.-M.E., Buza J.A., Fink L.A., Ahmad C.S., Bigliani L.U., et al. Factors affecting satisfaction and shoulder function in patients with a recurrent rotator cuff tear. J Bone Joint Surg Am. 2014;96:106–112. doi: 10.2106/JBJS.L.01649. [DOI] [PubMed] [Google Scholar]
- 29.Kim J.N., Park H.J., Kim M.S., Choi Y.J., Kim E., Park J.H., et al. Sonographic and elastographic findings after arthroscopic rotator cuff repair: a comparison with clinical results. Br J Radiol. 2023;96 doi: 10.1259/bjr.20210777. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Kim J.O., Lee J.-H., Kim K.-S., Ji J.-H., Koh S.-J., Lee J.-H. Rotator cuff bridging repair using acellular dermal matrix in large to massive rotator cuff tears: histologic and clinical analysis. J Shoulder Elbow Surg. 2017;26:1897–1907. doi: 10.1016/j.jse.2017.04.010. [DOI] [PubMed] [Google Scholar]
- 31.Kuechly H.A., Kurkowski S.C., Taleghani E.R., Shah N.S., Kloby M.A., Foster T.S., et al. Ultrasound and patient-reported outcomes of rotator cuff repair with new acellular human allograft at 6 months and 1 year post surgery. JSES Rev Rep Tech. 2024;4:413–418. doi: 10.1016/j.xrrt.2024.03.012. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Longo U.G., Carnevale A., Piergentili I., Berton A., Candela V., Schena E., et al. Retear rates after rotator cuff surgery: a systematic review and meta-analysis. BMC Musculoskelet Disord. 2021;22:749. doi: 10.1186/s12891-021-04634-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33.McIntyre L.F., Bishai S.K., Brown P.B., Bushnell B.D., Trenhaile S.W. Patient-Reported outcomes after use of a bioabsorbable collagen implant to treat partial and full-thickness Rotator Cuff tears. Arthroscopy. 2019;35:2262–2271. doi: 10.1016/j.arthro.2019.02.019. [DOI] [PubMed] [Google Scholar]
- 34.Omae H., Steinmann S.P., Zhao C., Zobitz M.E., Wongtriratanachai P., Sperling J.W., et al. Biomechanical effect of rotator cuff augmentation with an acellular dermal matrix graft: a cadaver study. Clin Biomech (Bristol) 2012;27:789–792. doi: 10.1016/j.clinbiomech.2012.05.001. [DOI] [PubMed] [Google Scholar]
- 35.Quigley R., Verma N., Evuarherhe A., Cole B.J. Rotator Cuff repair with graft augmentation improves function, decreases revisions, and is cost-effective. Arthroscopy. 2022;38:2166–2174. doi: 10.1016/j.arthro.2022.01.011. [DOI] [PubMed] [Google Scholar]
- 36.Randelli P.S., Menon A., Nocerino E., Aliprandi A., Feroldi F.M., Mazzoleni M.G., et al. Long-term results of Arthroscopic Rotator Cuff Repair: initial tear size matters: a prospective Study on clinical and radiological results at a minimum Follow-up of 10 years. Am J Sports Med. 2019;47:2659–2669. doi: 10.1177/0363546519865529. [DOI] [PubMed] [Google Scholar]
- 37.Ruiz Ibán M.A., García Navlet M., Moros Marco S., Diaz Heredia J., Hernando A., Ruiz Díaz R., et al. Augmentation of a Posterosuperior cuff repair with a bovine bioinductive Collagen Implant shows a lower retear rate but similar outcomes compared with no augmentation: 2-Year results of a randomized controlled trial. Arthroscopy. 2025;41:3869–3879. doi: 10.1016/j.arthro.2025.03.057. [DOI] [PubMed] [Google Scholar]
- 38.Ruiz I.M.Á., García N.M., Moros Marco S., Diaz Heredia J., Hernando Sánchez A., Ruiz Díaz R., et al. Augmentation of a transosseous-equivalent repair in Posterosuperior Nonacute Rotator Cuff tears with a bioinductive collagen implant decreases the retear rate at 1 year: a randomized controlled trial. Arthroscopy. 2024;40:1760–1773. doi: 10.1016/j.arthro.2023.12.014. [DOI] [PubMed] [Google Scholar]
- 39.Schlegel T.F., Abrams J.S., Angelo R.L., Getelman M.H., Ho C.P., Bushnell B.D. Isolated bioinductive repair of partial-thickness rotator cuff tears using a resorbable bovine collagen implant: two-year radiologic and clinical outcomes from a prospective multicenter study. J Shoulder Elbow Surg. 2021;30:1938–1948. doi: 10.1016/j.jse.2020.10.022. [DOI] [PubMed] [Google Scholar]
- 40.Shim I.K., Kang M.S., Lee E.-S., Choi J.H., Lee Y.N., Koh K.H. Decellularized Bovine pericardial patch loaded with mesenchymal stromal cells enhance the mechanical strength and biological healing of large-to-massive rotator Cuff Tear in a rat model. Arthroscopy. 2022;38:2987–3000. doi: 10.1016/j.arthro.2022.06.004. [DOI] [PubMed] [Google Scholar]
- 41.Sugaya H., Maeda K., Matsuki K., Moriishi J. Functional and structural outcome after arthroscopic full-thickness rotator cuff repair: single-row versus dual-row fixation. Arthroscopy. 2005;21:1307–1316. doi: 10.1016/j.arthro.2005.08.011. [DOI] [PubMed] [Google Scholar]
- 42.Tashjian R.Z., Hollins A.M., Kim H.-M., Teefey S.A., Middleton W.D., Steger-May K., et al. Factors affecting healing rates after arthroscopic double-row rotator cuff repair. Am J Sports Med. 2010;38:2435–2442. doi: 10.1177/0363546510382835. [DOI] [PubMed] [Google Scholar]
- 43.Tham E.R.X., Briggs L., Murrell G.A.C. Ultrasound changes after rotator cuff repair: is supraspinatus tendon thickness related to pain? J Shoulder Elbow Surg. 2013;22:e8–e15. doi: 10.1016/j.jse.2012.10.047. [DOI] [PubMed] [Google Scholar]
- 44.Thon S.G., O’Malley L., O’Brien M.J., Savoie F.H. Evaluation of healing rates and safety with a bioinductive collagen patch for large and massive rotator Cuff tears: 2-Year safety and clinical outcomes. Am J Sports Med. 2019;47:1901–1908. doi: 10.1177/0363546519850795. [DOI] [PubMed] [Google Scholar]
- 45.Warren J.R., Domingo-Johnson E.R., Sorensen A.A., Cheng A.-L., Latz K.H., Cil A. Bioinductive patch as an augmentation for rotator cuff repair, a systematic review and meta-analysis. J Shoulder Elbow Surg. 2024;33:2515–2529. doi: 10.1016/j.jse.2024.05.002. [DOI] [PubMed] [Google Scholar]
- 46.Yamaura K., Fujibayashi I., Kurosawa T., Mifune Y., Inui A., Ozaki T., et al. Timing of retears after arthroscopic rotator cuff repair and associated factors: a retrospective analysis. J Shoulder Elbow Surg. 2023;32:1929–1936. doi: 10.1016/j.jse.2023.01.026. [DOI] [PubMed] [Google Scholar]
- 47.Yanke A., Dandu N., Credille K., Damodar D., Wang Z., Cole B.J. Indications and technique: Rotator Cuff repair augmentation. J Am Acad Orthop Surg. 2023;31:1205–1210. doi: 10.5435/JAAOS-D-23-00101. [DOI] [PubMed] [Google Scholar]
- 48.Yoshida M., Collin P., Josseaume T., Lädermann A., Goto H., Sugimoto K., et al. Post-operative rotator cuff integrity, based on Sugaya’s classification, can reflect abduction muscle strength of the shoulder. Knee Surg Sports Traumatol Arthrosc. 2018;26:161–168. doi: 10.1007/s00167-017-4608-5. [DOI] [PubMed] [Google Scholar]
- 49.Zhang T., Ajayi A., Hajjar M., Fleckenstein C.M., Nolan J., Hasan S.S. Arthroscopic repair of retracted large and massive rotator cuff tears with and without augmentation with a bio-inductive collagen implant reveals substantial and comparable clinical improvement. Arthroscopy. 2024;40:1434–1442. doi: 10.1016/j.arthro.2023.10.024. [DOI] [PubMed] [Google Scholar]