Rotator cuff repair with biological graft augmentation causes adverse tissue outcomes.

Background and purpose - Biological patches can be used to augment rotator cuff tendon repair in an attempt to improve healing and reduce rates of re-rupture. However, little is known about the in vivo tissue response to these patches. We assessed native rotator cuff tissue response after surgical repair and augmentation with 2 commercially available extracellular matrix (ECM) patches. Patients and methods - Patients underwent a rotator cuff repair augmented with either GraftJacket (Wright Medical), Permacol (Zimmer Biomet), or no patch (Control), applied using an onlay technique. A sample of supraspinatus tendon was collected intraoperatively and 4 weeks post-surgery, using ultrasound-guided biopsy. Histology and immunohistochemistry were performed on all samples. Results - The Permacol group (n = 3) and GraftJacket group (n = 4) demonstrated some changes in native tendon ECM compared with the control group (n = 3). Significant disruption of the extracellular matrix of the repaired native supraspinatus, underlying both patches, was observed. The patches did not generally increase cellularity, foreign body giant cell count, or vascularity compared to the control group. 1 patient in the Permacol group had an adverse tissue immune response characterized by extensive infiltration of IRF5+, CD68+, and CD206+ cells, suggesting involvement of macrophages with a pro-inflammatory phenotype. No significant differences in protein expression of CD4, CD45, CD68, CD206, BMP7, IRF5, TGFß, and PDPN were observed among the groups. Interpretation - Histological and immunohistochemical analysis of native tendon tissue after patch augmentation in rotator cuff repair raises some concerns about a lack of benefit and potential for harm from these materials.

Vascularization and biocompatibility of poly(ε-caprolactone) fiber mats for rotator cuff tear repair.

Rotator cuff tear is the most frequent tendon injury in the adult population. Despite current improvements in surgical techniques and the development of grafts, failure rates following tendon reconstruction remain high. New therapies, which aim to restore the topology and functionality of the interface between muscle, tendon and bone, are essentially required. One of the key factors for a successful incorporation of tissue engineered constructs is a rapid ingrowth of cells and tissues, which is dependent on a fast vascularization. The dorsal skinfold chamber model in female BALB/cJZtm mice allows the observation of microhemodynamic parameters in repeated measurements in vivo and therefore the description of the vascularization of different implant materials. In order to promote vascularization of implant material, we compared a porous polymer patch (a commercially available porous polyurethane based scaffold from Biomerix™) with electrospun polycaprolactone (PCL) fiber mats and chitosan-graft-PCL coated electrospun PCL (CS-g-PCL) fiber mats in vivo. Using intravital fluorescence microscopy microcirculatory parameters were analyzed repetitively over 14 days. Vascularization was significantly increased in CS-g-PCL fiber mats at day 14 compared to the porous polymer patch and uncoated PCL fiber mats. Furthermore CS-g-PCL fiber mats showed also a reduced activation of immune cells. Clinically, these are important findings as they indicate that the CS-g-PCL improves the formation of vascularized tissue and the ingrowth of cells into electrospun PCL scaffolds. Especially the combination of enhanced vascularization and the reduction in immune cell activation at the later time points of our study points to an improved clinical outcome after rotator cuff tear repair.

Beige fibro-adipogenic progenitor transplantation reduces muscle degeneration and improves function in a mouse model of delayed repair of rotator cuff tears.

BACKGROUND: Muscle atrophy and fatty infiltration (FI) are common occurrences following rotator cuff (RC) tears. Tears of all sizes are subject to muscle degeneration. The degree of muscle degeneration following RC tears is highly correlated with repair success and functional outcomes. We have recently discovered that muscle fibro-adipogenic progenitors (FAPs) can differentiate into uncoupling protein 1 (UCP-1)-expressing beige adipocytes and induce muscle regeneration. This study evaluated the potential of local cell transplantation of beige adipose FAPs (BAT-FAPs) to treat RC muscle degeneration in a murine model of RC repair. METHODS: BAT-FAPs were isolated from muscle in UCP-1 reporter mice by flow cytometry as UCP-1+/Sca1+/PDGFR+/CD31-/CD45-/integrin α7-. C57/BL6J mice underwent supraspinatus tendon tear with suprascapular nerve transection followed by repair 2 or 6 weeks after the initial injury. At the time of repair, mice received either no additional treatment, phosphate-buffered saline injection, or BAT-FAP injection. Functional outcomes were assessed by gait analysis. Mice were humanely killed at 6 weeks after cell transplantation. Supraspinatus muscle FI, fibrosis, muscle fiber size, and vascularity were analyzed and quantified via ImageJ. Analysis of variance with post hoc Tukey test and P <.05 was used to determine statistical significance. RESULTS: Cell transplantation diminished fibrosis, FI, and atrophy and enhanced vascularization in both delayed repair models. Cell transplantation resulted in improved shoulder function as assessed with gait analysis in both the delayed repair models. CONCLUSIONS: BAT-FAPs significantly reduced muscle degeneration and improved shoulder function after RC repair. BAT-FAPs hold significant promise as a therapeutic adjunct to repair for patients with advanced RC pathology.

Blood flow evaluation by dynamic magnetic resonance imaging of symptomatic rotator cuff tears and frozen shoulders.

BACKGROUND: This study compared imaging findings of blood flow changes between symptomatic rotator cuff tear (RCT) and frozen shoulder (FS) by using 3-dimensional dynamic magnetic resonance imaging (MRI) to determine the clinical characteristics of symptomatic RCT. METHODS: The 2 study groups comprised 31 symptomatic RCT patients who underwent arthroscopic rotator cuff repair and 30 patients with FS. We denoted abnormal blood flow detected around the glenohumeral joint as the burning sign (BS). We evaluated the characteristics of dynamic MRI and compared them between BS-positive and BS-negative patients in the RCT group. RESULTS: All members of the FS group showed the BS. Conversely, the incidence of the BS in RCT patients was 53% (16 of 31). The BS in RCT and FS patients was observed in the rotator interval in 16 shoulders, in the axillary pouch in 3 shoulders (P < .01), and in the intertubercular groove in 10 RCT and 12 FS patients. In the RCT group, 16 patients with BS had a statistically significantly higher Numeric Rating Score at rest (P = .0005) and in motion (P = .04) than the 15 patients without BS and exhibited a higher rate of small and medium tears and a higher rate of shoulder contracture. CONCLUSION: Dynamic MRI of symptomatic RCT (53.3%) highlighted abnormal vascularization around the glenohumeral joint, which may be associated with pain and contracture in RCT as in FS.

Contrast-Enhanced Ultrasound Determines Supraspinatus Muscle Atrophy After Cuff Repair and Correlates to Functional Shoulder Outcome.

BACKGROUND: Muscle degeneration as a consequence of rotator cuff tears is mainly assessed by magnetic resonance imaging. Contrast-enhanced ultrasound (CEUS) is a new functional imaging method to assess microvascular perfusion as a fundamental parameter of muscle tissue vitality. In this cross-sectional study, the authors evaluated supraspinatus muscle perfusion after cuff repair and analyzed its association with functional shoulder outcome and the grade of echogenicity in B-mode ultrasound indicating fatty infiltration. HYPOTHESIS: The authors expected reduced microperfusion of the operated versus the contralateral supraspinatus muscle and a correlation of the muscular microperfusion with functional shoulder outcome. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Patients who received unilateral repair of the supraspinatus tendon between 2009 and 2014 were invited for a single follow-up examination. Functional scores were assessed, including the Constant-Murley score and American Shoulder and Elbow Surgeons score. CEUS examination was performed bilaterally in an oblique sagittal plane of the supraspinatus fossa. Perfusion was quantified by the parameters wash-in perfusion index (WiPI) and peak enhancement via VueBox quantification software. The results of the Constant-Murley score, American Shoulder and Elbow Surgeons score, and perfusion parameters were referenced to the contralateral shoulder. Echogenicity of the supraspinatus muscle was classified with a 3-point scale as compared with the trapezius muscle. RESULTS: Sixty-seven patients were available, with a mean follow-up of 38.0 ± 18.5 months. Functional assessment showed impaired shoulder function on the operated shoulder as compared with the contralateral side (relative Constant Score [CS], 80% ± 19%). CEUS revealed diminished perfusion on the operated shoulder (WiPI, 55.1% ± 40.2%, P < .001). A strong correlation could be demonstrated between the perfusion deficit and functional impairment (relative WiPI and CS: rs = .644, P < .001). Higher grade of echogenicity in B-mode ultrasound was associated with reduced perfusion. CONCLUSION: CEUS could visualize impaired supraspinatus muscle perfusion after rotator cuff repair as compared with the contralateral, healthy shoulder. With its ability to quantify microvascular perfusion as a surrogate parameter for muscle vitality and function, CEUS may serve as a quantitative method to evaluate rotator cuff muscles.

Perfusion of the Rotator Cuff Tendon According to the Repair Configuration Using an Indocyanine Green Fluorescence Arthroscope: A Preliminary Report.

BACKGROUND: The disturbance of rotator cuff tendon perfusion has been connected with the suture-bridge configuration repair (SBCR) technique; however, in vivo assessments of the tendon blood supply have been problematic with other modalities. An evaluation of tissue perfusion by an indocyanine green (ICG) fluorescence arthroscope has been developed to counteract this difficulty. PURPOSE: To verify the hindrance of perfusion in SBCR, we used an ICG fluorescence camera to compare parallel-type transosseous repair (PTR) and SBCR in rabbits immediately and at 3 days after rotator cuff repair. STUDY DESIGN: Controlled laboratory study. METHODS: Acute rotator cuff repair was performed on the shoulders of 10 rabbits. Both shoulders were repaired using either PTR or SBCR. For PTR, simple repair was performed through 2 parallel transosseous tunnels created using a microdrill. For SBCR, 2 additional crisscross transosseous tunnels were added to mimic arthroscopic SBCR. Immediately after repair, ICG was injected through the ear vein, and images were recorded using an ICG fluorescence camera. Tendon perfusion was compared by measuring fluorescence intensity using ImageJ software in both methods. At 3 days after rotator cuff repair, a reassessment of ICG fluorescence was performed. In addition, as a subsidiary study, a comparison of each repair method and a healthy tendon was performed (PTR vs healthy tendon and SBCR vs healthy tendon). Six rabbits (3 for each comparison) were included. RESULTS: Immediately after rotator cuff repair, the mean (±SD) grayscale intensity of ICG fluorescence was weaker in SBCR than PTR in 10 specimens (65.9 ± 47.6 vs 84.3 ± 53.4 per pixel, respectively; P = .003). At 3 days after repair, 8 specimens were included in the analysis because suture strands failed in 2 specimens in SBCR. The mean intensity of fluorescence was still weaker in SBCR compared with PTR (52.5 ± 13.7 vs 60.2 ± 22.7 per pixel, respectively; P = .077). The mean fluorescence intensity compared with a healthy tendon was 83.2% ± 9.5% in PTR and 63.2% ± 13.2% in SBCR. CONCLUSION: Our ICG fluorescence camera system was able to detect ICG fluorescence in an acute rabbit rotator cuff repair model. SBCR showed inferior tendon perfusion immediately after repair. At 3 days after repair, SBCR still showed inferior fluorescence intensity, although it did not reach statistical significance. CLINICAL RELEVANCE: In this study, SBCR hindered perfusion at the tendon in the compressed area. This finding may affect rotator cuff tendon healing and failure mode.

Tendon vascularity in overhead athletes with subacromial pain syndrome and its correlation with the resting subacromial space.

BACKGROUND: Supraspinatus tendinopathy is one of the common causes of subacromial pain syndrome (SAPS) in overhead athletes. Changes in tendon vascularity have been reported in painful tendons; however, the prevalence and distribution have not been investigated in young overhead athletes. METHODS: We conducted a cross-sectional study of 47 overhead athletes (male, 31; female, 16) aged 18 to 36 years with SAPS for >3 months. A sonographer graded the severity of the tendinopathy and area of vascularization. Ultrasound imaging was used to measure supraspinatus tendon thickness, vascularity, and resting subacromial space. A self-written program was used to semiquantify the intensity of vascularity, expressed as the vascular index. RESULTS: The majority (87.2%) of the participants had signs of tendinopathy in the supraspinatus tendon, and 40 (85.1%) of the tendinopathic tendons had vascularity. The majority (66.0%) of the vascularized subjects presented with minimal increase in vascularity, and 19.1% had moderate to severe vascularization. Most (79.2%) of the vascularization was observed in the pericortical region. The vascular index was negatively correlated with the resting subacromial space in male athletes with a reduced subacromial space (ρ = -0.63; P = .038). CONCLUSION: Of overhead athletes with SAPS, 87.2% had supraspinatus tendinopathy with minimal to moderate vascularization, with the majority of vascularization occurring in the pericortical region. In male athletes with a reduced subacromial space, greater vascularity in the supraspinatus tendon was associated with a smaller resting subacromial space.

Difference in vascular patterns between transosseous-equivalent and transosseous rotator cuff repair.

BACKGROUND: Vascularity is the important factor of biologic healing of the repaired tissue. The purpose of this study was to clarify sequential vascular patterns of repaired rotator cuff by suture techniques. METHODS: We randomized 21 shoulders in 20 patients undergoing arthroscopic rotator cuff repair into 2 groups: transosseous-equivalent repair (TOE group, n = 10) and transosseous repair (TO group, n = 11). Blood flow in 4 regions inside the cuff (lateral articular, lateral bursal, medial articular, and medial bursal), in the knotless suture anchor in the TOE group, and in the bone tunnel in the TO group was measured using contrast-enhanced ultrasound at 1 month, 2 months, 3 months, and 6 months postoperatively. RESULTS: The sequential vascular pattern inside the repaired rotator cuff was different between groups. The blood flow in the lateral articular area at 1 month, 2 months, and 3 months (P = .002, .005, and .025) and that in the lateral bursal area at 2 months (P = .031) in the TO group were significantly greater than those in the TOE group postoperatively. Blood flow was significantly greater for the bone tunnels in the TO group than for the knotless suture anchor in the TOE group at 1 month and 2 months postoperatively (P = .041 and .009). CONCLUSION: This study clarified that the sequential vascular pattern inside the repaired rotator cuff depends on the suture technique used. Bone tunnels through the footprint may contribute to biologic healing by increasing blood flow in the repaired rotator cuff.

Blood supply of the subacromial bursa and rotator cuff tendons on the bursal side.

PURPOSE: Vascularity of the subacromial bursa and rotator cuff tendons is key factors in the pathogenesis of subacromial bursitis and impingement syndrome, rotator cuff tendinitis, and rotator cuff tears. The purpose of this study was to investigate and describe blood supply to the cranial and caudal parts of the subacromial bursa and the vascularity of the rotator cuff tendons on the bursal side. METHODS: Fourteen fresh cadaveric shoulders from six females and eight males with a mean age of 71.7 (±10.8) years were studied. Before dissection, an arterial injection of 10% aqueous dispersion of latex was administered. Post-injection, the shoulders were fixed in an alcohol-formalin-glycerol solution. RESULTS: The cranial and caudal bursa of all specimens was mainly supplied by the thoracoacromial, suprascapular, and anterior and posterior circumflex humeral arteries. The cranial part of the bursa was supplied anteriorly by the thoracoacromial artery, and posteriorly and medially by the posterior circumflex humeral artery as far as the medial third. The caudal part received arterial blood anteriorly from the anterior circumflex humeral artery, and posteriorly and medially by the posterior circumflex humeral artery as far as the medial third of the caudal bursa. In addition, the suprascapular artery branched at the upper surface of the coracohumeral ligament, and the subcoracoid artery branched at the under surface of the same ligament. CONCLUSION: The subacromial bursa appears well vascularized. The results of the present investigation showed that blood supply to the subacromial bursa at the caudal part and rotator cuff tendons on the bursal side was linked to the same arteries. The subcoracoid artery supplied interval rotator structures close to the caudal bursa. It is the wish of the authors that this meticulous anatomical work will help surgeons in their day-to-day clinical work, e.g. to minimize the risk of complications such as perioperative bleeding.

Healing disturbance with suture bridge configuration repair in rabbit rotator cuff tear.

BACKGROUND: Medial row failure has been reported in the suture bridge technique of rotator cuff repair. This study compared the healing response of suture bridge configuration repair (SBCR) and parallel type transosseous repair (PTR). METHODS: Acute rotator cuff repair was performed in 32 rabbits. Both shoulders were repaired using PTR or SBCR. In PTR, simple PTR was performed through 2 parallel transosseous tunnels created using a microdrill. In SBCR, 2 additional crisscross transosseous tunnels were added to mimic arthroscopic SBCR. At 1, 2, and 5 weeks postoperatively, comparative biomechanical testing was performed in 8 rabbits, and histologic analysis, including immunohistochemical staining for CD31, was performed in 4 rabbits. RESULTS: Failure loads at 1 week (38.12 ± 20.43 N vs 52.00 ± 27.23 N; P = .284) and 5 weeks (97.93 ± 48.35 N vs 119.60 ± 60.81 N; P = .218) were not statistically different between the SBCR and PTR groups, respectively, but were significantly lower in the SBCR group than in the PTR group (23.56 ± 13.56 N vs. 44.25 ± 12.53 N; P = .009), respectively, at 2 weeks. Markedly greater fibrinoid deposition was observed in the SBCR group than in the PTR group at 2 weeks. For vascularization, there was a tendency that more vessels could be observed in PTR than in SBCR at 2 weeks (15.9 vs 5.6, P = .068). CONCLUSIONS: In a rabbit acute rotator cuff repair model, SBCR exhibited inferior mechanical strength, and fewer blood vessels were observed at the healing site at 2 weeks postoperatively. Medial row tendon failure was more common in SBCR. Surgeons should consider the clinical effect of SBCR when performing rotator cuff repair.

Microvascular blood flow in normal and pathologic rotator cuffs.

BACKGROUND: Microvascular blood flow in the tendon plays an important role in the pathogenesis of rotator cuff abnormalities. There are conflicting views about the presence of a hypovascular zone in the supraspinatus tendon. Besides, no studies have looked at the pattern of blood flow around a partial-thickness tear. Our aim was to measure microvascular blood flow in normal and a range of pathologic rotator cuff tendons using laser doppler flowmetry. METHODS: A total of 120 patients having arthroscopic shoulder surgery were divided into 4 equal groups on the basis of their intraoperative diagnosis: normal rotator cuff, subacromial impingement syndrome, and partial-thickness or full-thickness rotator cuff tear. Microvascular blood flow was measured at 5 different regions of each cuff using a laser doppler probe. The values were compared to assess variability within and between individuals. RESULTS: Total blood flow was greater in the normal rotator cuff group compared with the groups with pathologic rotator cuffs, with the largest difference seen in the subacromial impingement group. Within individuals, blood flow was highest at the musculotendinous junction and lowest at the lateral insertional part of the tendon. Among groups, the blood flow was significantly lower at the anteromedial and posteromedial cuff in the groups with impingement and full-thickness tears compared with the group with normal cuff. CONCLUSION: Real-time in vivo laser doppler analysis has shown that microvascular blood flow is not uniform throughout the supraspinatus tendon. Blood flow in the pathologic supraspinatus tendon was significantly lower compared with the normal tendon.

rhPDGF-BB promotes early healing in a rat rotator cuff repair model.

BACKGROUND: Tendon-bone healing after rotator cuff repair occurs by fibrovascular scar tissue formation, which is weaker than a normal tendon-bone insertion site. Growth factors play a role in tissue formation and have the potential to augment soft tissue healing in the perioperative period. QUESTIONS/PURPOSES: Our study aim was to determine if rhPDGF-BB delivery on a collagen scaffold can improve tendon-to-bone healing after supraspinatus tendon repair compared with no growth factor in rats as measured by (1) gross observations; (2) histologic analysis; and (3) biomechanical testing. METHODS: Ninety-five male Sprague-Dawley rats underwent acute repair of the supraspinatus tendon. Rats were randomized into one of five groups: control (ie, repair only), scaffold only, and three different platelet-derived growth factor (PDGF) doses on the collagen scaffold. Animals were euthanized 5 days after surgery to assess cellular proliferation and angiogenesis. The remaining animals were analyzed at 4 weeks to assess repair site integrity by gross visualization, fibrocartilage formation with safranin-O staining, and collagen fiber organization with picrosirius red staining, and to determine the biomechanical properties (ie, load-to-failure testing) of the supraspinatus tendon-bone construct. RESULTS: The repaired supraspinatus tendon was in continuity with the bone in all animals. At 5 days, rhPDGF-BB delivery on a scaffold demonstrated a dose-dependent response in cellular proliferation and angiogenesis compared with the control and scaffold groups. At 28 days, with the numbers available, rhPDGF-BB had no effect on increasing fibrocartilage formation or improving collagen fiber maturity at the tendon-bone insertion site compared with controls. The control group had higher tensile loads to failure and stiffness (35.5 ± 8.8 N and 20.3 ± 4.5 N/mm) than all the groups receiving the scaffold, including the PDGF groups (scaffold: 27 ± 6.4 N, p = 0.021 and 13 ± 5.7 N/mm, p = 0.01; 30 µg/mL PDGF: 26.5 ± 7.5 N, p = 0.014 and 13.3 ± 3.2 N/mm, p = 0.01; 100 µg/mL PDGF: 25.7 ± 6.1 N, p = 0.005 and 11.6 ± 3.3 N/mm, p = 0.01; 300 µg/mL PDGF: 27 ± 6.9 N, p = 0.014 and 12.7 ± 4.1 N/mm, p = 0.01). CONCLUSIONS: rhPDGF-BB delivery on a collagen scaffold enhanced cellular proliferation and angiogenesis during the early phase of healing, but this did not result in either a more structurally organized or stronger attachment site at later stages of healing. The collagen scaffold had a detrimental effect on healing strength at 28 days, and its relatively larger size compared with the rat tendon may have caused mechanical impingement and extrinsic compression of the healing tendon. Future studies should be performed in larger animal models where healing occurs more slowly. CLINICAL RELEVANCE: Augmenting the healing environment to improve the structural integrity and to reduce the retear rate after rotator cuff repair may be realized with continued understanding and optimization of growth factor delivery systems.

In vivo blood flow after rotator cuff reconstruction in a sheep model: comparison of single versus double row.

PURPOSE: Arthroscopic double-row (DR) suture anchor repair of rotator cuff tears has been shown to be superior to most single-row (SR) techniques with regard to footprint reconstruction, load to failure and tendon-to-bone contact pressures. The hypothesis of this study was that the greater contact pressures of DR techniques would compromise blood flow to a higher degree than SR repair. The aim of this experimental study was to evaluate the effect of a DR and a SR technique on tendon blood flow in a sheep model. METHODS: Eighteen sheep underwent detachment and immediate repair of the infraspinatus tendon using either a Mason-Allen or a suture-bridge technique. Tendon blood flow was measured using laser Doppler flowmetry before detachment, immediately after repair and 12 weeks thereafter. Six regions of interest were measured, three over the lateral and three over the medial aspect of the footprint. RESULTS: Immediately after repair, tendon blood flow decreased significantly in both repair groups (P = 0.004). In the SR group, blood flow decreased by 100.1 arbitrary units (AU) (83.6 %) after repair, in the DR by 81.4 AU (90.5 %). Subgroup analysis showed blood flow over the lateral aspect of the footprint decreased by 126.3 AU (92.2 %) in the SR and 84.4 AU (90.9 %) in the DR group, whereas over the medial aspect, it decreased by 73.9 AU (72.0 %) in the SR and 78.5 AU (90.1 %) in the DR group. None of the differences between the groups were significant. At 12 weeks, measured blood flow in the DR group had increased to 90.1 AU (100.2 %) compared to the native tendons and was at 72.5 AU (60.5 %) for the SR group. Again, the difference between SR and DR group was not statistically significant (n.s.). Assessment for retears showed that 4 of 8 tendons (50 %) in the DR group and 3 of 9 tendons (33.3 %) in the SR group had to be classified as re-ruptures. CONCLUSION: Suture anchor repair leads to an intraoperative decrease in tendon blood flow regardless of the repair technique. A significant difference between SR and DR repair was not found. These findings indicate that tendon blood flow should not be a factor to determine the use of either repair technique over the other.

Arterial variations of the subclavian-axillary arterial tree: its association with the supply of the rotator cuff muscles / Variaciones arteriales del árbol arterial subclavio-axilar: su asociación con la irrigación del manguito de los rotadores

The subclavian-axillary arterial tree is responsible for the arterial supply to the rotator cuff muscles as well as other shoulder muscles. This study comprised the bilateral dissection of the shoulder and upper arm region in thirty-one adult and nineteen fetal cadaveric specimens. The variable origins and branching patterns of the axillary, subscapular, circumflex scapular, thoracodorsal, posterior circumflex humeral and suprascapular arteries identified in this study corroborated the findings of previous studies. In addition, unique variations that are unreported in the literature were also observed. The precise anatomy of the arterial distribution to the rotator cuff muscles is important to the surgeon and radiologist. It will aid proper interpretation of radiographic images and avoid injury to this area during surgical procedures.

El árbol arterial subclavio-axilar, es responsable del suministro arterial de los músculos correspondientes al manguito de los músculos rotadores, así como de otros músculos del hombro. Este estudio comprende la disección bilateral del hombro y la región superior del brazo en 31 cadáveres adultos y 19 fetos. Las variables y patrones del origen, ramificación de las arterias axilar, subescapular, circunfleja escapular, toracodorsal, circunfleja humeral posterior y supraescapular, identificados en este estudio, corroboran los hallazgos de estudios anteriores. Además, se observaron variaciones únicas no comunicadas previamente en la literatura. La anatomía precisa de la distribución arterial de los músculos del manguito de los músculos rotadores es importante para el cirujano y el radiólogo. Esta información constituirá una ayuda para la adecuada interpretación de imágenes radiológicas y para evitar lesiones en esta área durante los procedimientos quirúrgicos.

Arterial supply to the rotator cuff muscles / Suministro arterial de los músculos del manguito rotador

The arterial supply to the rotator cuff muscles is generally provided by the subscapular, circumflex scapular, posterior circumflex humeral and suprascapular arteries. This study involved the bilateral dissection of the scapulohumeral region of 31 adult and 19 fetal cadaveric specimens. The subscapularis muscle was supplied by the subscapular, suprascapular and circumflex scapular arteries. The supraspinatus and infraspinatus muscles were supplied by the suprascapular artery. The infraspinatus and teres minor muscles were found to be supplied by the circumflex scapular artery. In addition to the branches of these parent arteries, the rotator cuff muscles were found to be supplied by the dorsal scapular, lateral thoracic, thoracodorsal and posterior circumflex humeral arteries. The variations in the arterial supply to the rotator cuff muscles recorded in this study are unique and were not described in the literature reviewed. Due to the increased frequency of operative procedures in the scapulohumeral region, the knowledge of variations in the arterial supply to the rotator cuff muscles may be of practical importance to surgeons and radiologists.

El suministro arterial a los músculos del manguito rotador generalmente es proporcionado por las arterias subescapular, circunfleja escapular, circunfleja humeral posterior y supraescapular. Se realizó la disección bilateral de la región escapulo humeral de 31 especímenes cadavéricos adultos y 19 fetos. El músculo subescapular estaba irrigado por las arterias subescapular, supraescapular y circunfleja escapular. Por otra parte, la arteria supraescapular irrigaba a los músculos supra e infraespinoso. Observamos que los músculos infraespinoso y redondo menor fueron irrigados por la arteria circunfleja escapular. Además de las arterias de origen y sus ramas, observamos que los músculos del manguito rotador son irrigados por la arteria escapular dorsal y las arterias torácica lateral, toracodorsal y circunfleja humeral posterior. Las variaciones en la irrigación de los músculos del manguito rotador registrados en este estudio son únicos y no existe una descripción referente a ellos en la literatura revisada. Debido a la mayor frecuencia de los procedimientos quirúrgicos en la región escápulohumeral, el conocimiento de las variaciones de la irrigación de los músculos del manguito rotador puede ser de importancia práctica para cirujanos y radiólogos.

Superficial blood flow of the superior labrum associated with rotator cuff tear using laser Doppler flowmeter.

INTRODUCTION: Superior labrum anterior and posterior (SLAP) lesions due to overuse by repeated pitching motion and trauma are often noted and usually. However, shoulder disorders with a chronic course are often accompanied by SLAP lesions. SLAP lesions are frequently observed during arthroscopic surgery of the shoulder joint for rotator cuff tear in middle-aged and elderly individuals, suggesting the involvement of factors other than pitching motion and traumatic events in the pathogenesis. We considered that blood flow in the labrum is altered. The purpose of this study was to clarify the superficial blood flow in the superior labrum during arthroscopic surgery of the rotator cuff tear and investigate whether it is altered with labrum injury. MATERIALS AND METHODS: We evaluated 33 subjects with a mean age of 55.1 years who underwent arthroscopic surgery for partial or complete rotator cuff tears. The blood flow measurement site for the superior labrum was set at the supraglenoid tubercle attachment site, and blood flow was measured twice using laser Doppler flowmeter. The mean was calculated and compared among the normal labrum and type 1 SLAP lesions. RESULTS: The morphology of the labrum was normal in 16 subjects, and 17 subjects had type 1 SLAP lesions. The mean blood flow was 1.75 ml/min/100 g in subjects with a normal labrum; however, in subjects with type 1 SLAP lesions, blood flow was 1.32 ml/min/100 g, showing significant differences (P < 0.01). CONCLUSION: Superficial blood flow in the superior labrum of the shoulder with rotator cuff tear was measured using laser Doppler flowmetry. The blood flow in type 1 SLAP lesions was lower than that in the normal labrum.

Arterial supply of the tendinous rotator cuff insertions: an anatomical study.

BACKGROUND: Confirming the presence of arteries crossing the osteotendinous junctions (OTJs) of the rotator cuff may explain why rates of avascular necrosis (AVN) of the humeral head vary between three- and four-part proximal humeral fractures. It is hypothesized that the humeral head remains better vascularized in three-part fractures because one tuberosity with its inserting rotator cuff tendons is still attached to the articular fragment and supplying it with blood. METHODS: Eighty rotator cuff tendons from 20 shoulder girdles of cadavers aged 68-94 years were studied. In six shoulder girdles, the anterior circumflex humeral artery and posterior circumflex humeral artery (PCHA) were injected with ink, and the extra- and intraosseous courses of the vasculature were dissected until the OTJs of the rotator cuff. RESULTS: The rotator cuff insertions received an arterial supply across their OTJs in 50% of cases (75% in supraspinatus, 67% in subscapularis, 33% in infraspinatus and 20% in teres minor). Supraspinatus and subscapularis insertions were vascularized by the arcuate artery, while the insertions of infraspinatus and teres minor were supplied by an unnamed terminal branch of the PCHA. This was named 'posterolateral artery'. CONCLUSION: The presence of arteries crossing the OTJs of the rotator cuff, as well as the differences in the frequency arteries crossed the OTJs of individual rotator cuff tendons, may help explain why there is a lower rate of AVN of the humeral head in thee-part, compared with four-part proximal humeral fractures.

Arthroscopic suture bridge transosseus equivalent fixation of rotator cuff tendon preserves intratendinous blood flow at the time of initial fixation.

BACKGROUND: Current etiologic theories concerning healing rates in rotator cuff repair have focused on the blood supply in the tendinous portion of the cuff. We currently have little information regarding the effect of our repair techniques on this critical variable. We hypothesize that intratendinous blood flow is changed during transosseus equivalent tendon fixation. METHODS: Eighteen consecutive patients with rotator cuff tears amenable to double row fixation were included in the study. Each patient underwent a standard arthroscopic transosseous equivalent double row fixation procedure using the Arthrex SutureBridge technique (Arthrex, Naples, FL, USA). After tying down of the medial row, a first set of recordings was taken using a custom laser doppler flowmetry probe (Perimed, Inc., Ohio, USA). A second recording was made following securing of the lateral PushLock anchors. The data were compared to determine the overall effect on blood flow associated with this technique. RESULTS: Summated averages for the 2 groups show a significant (44.67%) decline in the blood flow present after the second row of implants are placed (P < .01). Individual calculations for regions of the cuff tear indicate significant differences in anterior third (P = .01), middle third (P < .01), and posterior third (P = .02) of the tear after transosseous equivalent fixation. CONCLUSION: Completion of the construct with lateral anchors in the transosseous equivalent technique results in reduced but preserved blood flow in the tendon repair site. Further study is required to determine the implications for tendon healing. CLINICAL RELEVANCE: Intratendinous blood flow is a variable that should be considered when evaluating repair methods in rotator cuff surgery.

Contrast-enhanced ultrasound characterization of the vascularity of the repaired rotator cuff tendon: short-term and intermediate-term follow-up.

BACKGROUND: The objectives of this study were to characterize and compare the vascularity of arthroscopically repaired rotator cuff tendons at short-term and intermediate-term follow-up. MATERIALS AND METHODS: Nineteen patients who underwent arthroscopic rotator cuff repair were prospectively monitored for an average of 21.2 months. Initial baseline, grayscale ultrasound images of the operated-on shoulder were obtained on all patients at 3 months and at a minimum of 10 months postoperatively. Perflutren-lipid microsphere contrast (DEFINITY, Lantheus Medical Imaging, North Billerica, MA, USA) was injected after baseline grayscale images and after exercise to obtain contrast-enhanced images of the repair. Three regions of interest--supraspinatus tendon, peribursal tissue, and bone anchor site--were evaluated before and after rotator cuff-specific exercises. RESULTS: The peribursal tissue demonstrated the greatest blood flow, followed by the bone anchor site and tendon, in pre-exercise and postexercise states. Significantly less blood flow was observed in all regions of interest before exercise (P < .05) and only at the bone anchor site after exercise (P < .001) at latest follow-up compared with the 3-month values. Intratendinous blood flow remained relatively low at both evaluation points after surgical repair. CONCLUSION: Preliminary findings suggest that the peribursal tissue and bone anchor site are the main conduits of blood flow for the rotator cuff tendon after arthroscopic repair, with the supraspinatus tendon being relatively avascular. Blood flow of the repaired rotator cuff tendon decreases with time. Furthermore, exercise significantly enhances blood flow to the repaired rotator cuff.