Rooting Rotator Cuff Reconstruction for Irreparable Posterior-Superior Rotator Cuff Tear

Effect of Anterior Acromial Coverage on Functional and Radiological Outcomes After Arthroscopic Repair of Anteroposterior Massive Rotator Cuff Tears

BACKGROUND

Rotator cuff tear size, fatty infiltration, and scapular morphology are correlated with tendon healing and functional outcomes after arthroscopic repair; however, the association between anteroposterior acromial coverage and the clinical outcomes of anteroposterior massive rotator cuff tears (AP-MRCTs; involving all 3 tendons) remains unclear.

PURPOSE

To identify the association between AP acromial coverage and functional and radiological outcomes after arthroscopic repair of AP-MRCTs.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 98 patients who underwent arthroscopic repair of AP-MRCTs between January 2015 and December 2020 were included in the study and classified according to whether anterior acromial coverage (AAC) was anterior (46 patients; positive AAC group) or posterior (52 patients; negative AAC group) to the scapular line on true lateral shoulder radiographs. Demographic characteristics, surgical details, and functional outcomes were prospectively collected. Acromial morphological features, global tear extension (GTE), the global fatty infiltration index (GFII), tendon integrity after repair, proximal humeral migration, and glenohumeral abduction were measured and calculated on radiographs or magnetic resonance imaging scans preoperatively and at 2 years postoperatively. Multivariate logistic regression was performed to identify the independent risk factors of a rotator cuff retear.

RESULTS

The positive AAC group showed larger AAC, posterior acromial tilt, and anterior acromial slope as well as smaller posterior acromial coverage compared with the negative AAC group. Postoperatively, the American Shoulder and Elbow Surgeons score (82.5 ± 8.3 vs 77.2 ± 11.5, respectively; P = .013), active abduction (157.8°± 27.1° vs 142.7°± 39.6°, respectively; P = .048), and glenohumeral abduction (45.6°± 10.4° vs 39.7°± 14.9°, respectively; P = .041) in the positive AAC group were significantly higher than those in the negative AAC group, while the retear rate (23.9% vs 44.2%, respectively; P = .035) and proximal humeral migration (1.7 ± 1.0 vs 2.3 ± 1.2 mm, respectively; P = .006) were significantly lower in the positive AAC group than in the negative AAC group. Smaller AAC (odds ratio [OR], 0.93 [95% CI, 0.87-1.00]; P = .040), larger GTE (OR, 1.03 [95% CI, 1.01-1.06]; P = .017), and a higher GFII (OR, 3.49 [95% CI, 1.09-11.19]; P = .036) were associated with an increased risk of a rotator cuff retear.

CONCLUSION

Increased AAC was associated with a lower retear rate and better functional outcomes after arthroscopic repair of AP-MRCTs. A preliminary risk evaluation integrating GTE, the GFII, and AAC is recommended to consider the necessity of additional procedures for patients in need of arthroscopic rotator cuff repair.

Early Treatment of Shoulder Pathology Is Necessary but Not Enough Is Being Performed

Delayed treatment of shoulder instability results in bone loss requiring more-complicated surgery, in turn resulting in less-optimal outcomes. Similarly, delayed treatment of repairable rotator cuff tears results in irreparable tears requiring more-complicated surgery and resulting in less-optimal outcomes. Delayed treatment of shoulder pathology is a problem. Solutions include education and research investigation.

Biomechanical and Histological Results of Dual-Suspensory Reconstruction Using Banded Tendon Graft to Bridge Massive Rotator Cuff Tears in a Chronic Rabbit Model

BACKGROUND

Bridging rotator cuff tendon defects with a patch is a reasonable treatment for massive rotator cuff tears (MRCTs). However, the poor outcomes associated with routine patch repair have prompted exploration into superior bridging techniques and graft structures.

PURPOSE

To detect whether dual-suspensory reconstruction using a banded graft would be superior to routine bridging using a patch graft to treat MRCTs and to detect the comparative effectiveness of patellar tendon (PT) and fascia lata (FL) grafts in dual-suspensory reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Unilateral chronic MRCTs were created in 72 mature male New Zealand White rabbits, which were randomly divided into 3 groups: (1) patch bridging repair using rectangular FL autograft (PR-FL), (2) dual-suspensory bridging reconstruction using banded FL autograft (DSR-FL), and (3) dual-suspensory bridging reconstruction using banded PT autograft (DSR-PT). In each group, the mean failure load and stiffness of the cuff-graft-humerus (C-G-H) complexes of 6-week and 12-week specimens were recorded, with the failure modes and sites noted. Moreover, cuff-to-graft and graft-to-bone interface healing and graft substance remodeling of the complexes were histologically evaluated (via hematoxylin and eosin, Picrosirius red, Masson trichrome, and Safranin O/fast green staining) at 6 and 12 weeks to assess integrations between the bridging constructs and the native bone or rotator cuff tendons.

RESULTS

The DSR-PT group had the greatest mean failure loads and stiffness of the C-G-H complexes at 6 and 12 weeks (41.81 ± 7.00 N, 10.34 ± 2.68 N/mm; 87.62 ± 9.20 N, 17.98 ± 1.57 N/mm, respectively), followed by the DSR-FL group (32.04 ± 5.49 N, 8.20 ± 2.27 N/mm; 75.30 ± 7.31 N, 14.39 ± 3.29 N/mm, respectively). In the DSR-PT and DSR-FL groups, fewer specimens failed at the graft-to-bone junction and more failed at the cuff-to-graft junction, but both groups had higher median failure loads at 6 and 12 weeks (DSR-PT: cuff-to-graft junction, 37.80 and 83.76 N; graft-to-bone junction, 45.46 and 95.86 N) (DSR-FL: cuff-to-graft junction, 28.52 and 67.68 N; graft-to-bone junction, 37.92 and 82.18 N) compared with PR-FL (cuff-to-graft junction, 27.17 and 60.04 N; graft-to-bone junction, 30.12 and 55.95 N). At 12 weeks, the DSR-FL group had higher median failure loads at graft substance (72.26 N) than the PR-FL group (61.27 N). Moreover, the PR-FL group showed more inflammatory responses at the 2 healing interfaces and the graft substance in the 6-week specimens and subsequently displayed poorer interface healing (assessed via collagen organization, collagen maturity, and fibrocartilage regeneration) and graft substance remodeling (assessed via collagen organization and maturity) in 12-week specimens compared with the DSR-PT and DSR-FL groups. Superior interface healing and substance remodeling processes were observed in the DSR-PT group compared with the DSR-FL group.

CONCLUSION

When compared with routine patch repair, the dual-suspensory reconstructions optimized biomechanical properties and improved interface healing and graft substance remodeling for bridging MRCTs. Furthermore, the dual-suspensory technique using the PT graft presented superior histological and biomechanical characteristics than that using FL.

CLINICAL RELEVANCE

The dual-suspensory reconstruction technique using banded tendon grafts may enhance bridging constructs for MRCTs in humans, warranting further investigations of clinical outcomes.

The Plug-Type Patch Results in Immediate and Postoperative Advantages in Graft-to-Bone Integration for Bridging Massive Rotator Cuff Tears in a Chronic Rabbit Model

BACKGROUND

Various patches have been used to bridge massive rotator cuff tears (MRCTs) by reconnecting the cuff tendons to the humeral head, but the outcomes continue to be suboptimal. Notably, the graft-bone junction is a vulnerable site for failure, which requires optimization in patch design and techniques to enhance initial and postoperative fixation strength at the graft-bone interface.

HYPOTHESIS

The plug-type patch (Plug-Pat) through intratunnel fixation would optimize mechanical characteristics in initial graft-to-bone fixation and subsequently improve postoperative biomechanical and histological properties in graft-to-bone healing when compared with the routine rectangular patch (Rect-Pat).

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 60 mature male New Zealand White rabbits underwent acute rotator cuff defects to create chronic models with MRCTs. The fascia lata autograft was then harvested to prepare a Plug-Pat, which was distally rooted in the bone tunnel and proximally sutured to native tendons in a horizontal mattress fashion to reconnect the humeral head and cuff tendons. The control group was repaired with a routine Rect-Pat that was secured onto the bone surface for graft-bone fixation. After surgery, the cuff-graft-bone complexes of rabbits in both groups were harvested immediately (0 weeks) for time-zero initial fixation strength and refreshed contact area assessment, and at 6 or 12 weeks for postoperative biomechanical and histological evaluation.

RESULTS

The Plug-Pat significantly enhanced initial fixation strength in comparison with the Rect-Pat (mean ± SD; failure load, 36.79 ± 4.53 N vs 24.15 ± 2.76 N; P < .001) and decreased failure at the graft-bone interface of the construct at 0 weeks, with a significantly increased refreshed bone bed contact area (52.63 ± 2.97 mm² vs 18.28 ± 1.60 mm²; P < .001) between the graft and bone. At 6 and 12 weeks postoperatively, the Plug-Pat similarly resulted in greater failure load (43.15 ± 4.53 N vs 33.74 ± 2.58 N at 6 weeks; P = .001; 76.65 ± 5.04 N vs 58.17 ± 5.06 N at 12 weeks; P < .001) and stiffness (10.77 ± 2.67 N/mm vs 8.43 ± 0.86 N/mm at 6 weeks; P = .066; 16.98 ± 2.47 N/mm vs 13.21 ± 1.66 N/mm at 12 weeks; P = .011), with less specimen failure at the graft-bone interface than the Rect-Pat. In histological analyses, the Plug-Pat had a higher postoperative graft-bone integration score than the Rect-Pat, showing a more mature intratunnel healing interface with fibrocartilage tidemark formation, improved collagen properties, and more oriented cells when compared with those at the surface healing interface in the Rect-Pat.

CONCLUSION

The Plug-Pat enhanced initial fixation strength and enlarged the refreshed contact area for graft-bone connection at time zero and subsequently improved postoperative biomechanical properties and graft-bone integration at the graft-bone healing interface when compared with the Rect-Pat.

CLINICAL RELEVANCE

The Plug-Pat using intratunnel fixation may be a promising strategy for patch design to optimize its initial and postoperative graft-bone connection for bridging reconstruction of MRCTs.

Crimped nanofiber scaffold mimicking tendon-to-bone interface for fatty-infiltrated massive rotator cuff repair

Electrospun fibers, with proven ability to promote tissue regeneration, are widely being explored for rotator cuff repairing. However, without post treatment, the microstructure of the electrospun scaffold is vastly different from that of natural extracellular matrix (ECM). Moreover, during mechanical loading, the nanofibers slip that hampers the proliferation and differentiation of migrating stem cells. Here, electrospun nanofiber scaffolds, with crimped nanofibers and welded joints to biomimic the intricate natural microstructure of tendon-to-bone insertion, were prepared using poly(ester-urethane)urea and gelatin via electrospinning and double crosslinking by a multi-bonding network densification strategy. The crimped nanofiber scaffold (CNS) features bionic tensile stress and induces chondrogenic differentiation, laying credible basis for in vivo experimentation. After repairing a rabbit massive rotator cuff tear using a CNS for 3 months, the continuous translational tendon-to-bone interface was fully regenerated, and fatty infiltration was simultaneously inhibited. Instead of micro-CT, μCT was employed to visualize the integrity and intricateness of the three-dimensional microstructure of the CNS-induced-healed tendon-to-bone interface at an ultra-high resolution of less than 1 μm. This study sheds light on the correlation between nanofiber post treatment and massive rotator cuff repair and provides a general strategy for crimped nanofiber preparation and tendon-to-bone interface imaging characterization.

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Electrospun scaffold mimicking the microstructure of ECM was fabricated.

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The translational microstructure of tendon-to-bone interface was regenerated.

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Tendon-to-bone interface was 3D visualized with resolution less than 1 μm.

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Muscle fatty infiltration was inhibited for massive rotator cuff tear.