Current research trends on the effect of diabetes mellitus on rotator cuff tendon healing/tendinopathy

Rotator cuff tendon tears are a leading cause of shoulder pain. They are challenging to treat, and tendon-bone healing has a high failure rate despite successful surgery. Tendons connect the muscles and bones, which make them important for the body's overall mobility and stability. Metabolic diseases, including diabetes or high blood pressure, can affect the healing process after repair of a damaged tendon. With a global incidence of 9.3%, diabetes is considered as a significant risk factor for rotator cuff tendon healing because it causes structural, inflammatory, and vascular changes in the tendon. However, the mechanisms of how diabetes affects tendon healing remain unknown. Several factors have been suggested, including glycation product accumulation, adipokine dysregulation, increased levels of reactive oxygen species, apoptosis, inflammatory cytokines, imbalanced matrix-metalloproteinase-to-tissue-inhibitor ratio, and impaired angiogenesis and differentiation of the tendon sheath. Despite the effects of diabetes on tendon function and healing, few treatments are available to improve recovery in these patients. This review summarizes the current literature on the pathophysiological changes of the tendon in diabetes and hyperlipidemia. Preclinical and clinical evidence regarding the association between diabetes and tendon healing is presented. Moreover, current approaches to improve tendon healing in patients with diabetes are reviewed.

Tranexamic Acid Can Reduce Early Tendon Adhesions After Rotator Cuff Repair and Is Not Detrimental to Tendon-Bone Healing: A Comparative Animal Model Study

PURPOSE

To determine the effects of topical tranexamic acid (TXA) administration on tendon adhesions, shoulder range of motion (ROM), and tendon healing in an acute rotator cuff repair rat model.

METHODS

A total of 20 Sprague Dawley rats were used. Tendon adhesion, ROM, and biomechanical and histological analysis of tendon-bone healing was conducted at 3 and 6 weeks after surgery. The rats underwent rotator cuff repair surgery on both shoulders and were administered TXA via subacromial injections. The tendon adhesion was evaluated macroscopically and histologically. Biomechanical tendon healing was measured using a universal testing machine, and histological analysis was quantified by H&E, Masson's trichrome, and picrosirius red staining.

RESULTS

At 3 weeks after surgery, the adhesion score was significantly lower in the TXA group (2.10 ± 0.32) than in the control group (2.70 ± 0.48) (P = .005), but there was no significant difference between the 2 groups at 6 weeks. Regarding ROM, compared with the control group, the TXA group showed significantly higher external rotation (36.35° ± 4.52° vs 28.42° ± 4.66°, P < .001) and internal rotation (45.35° ± 9.36° vs 38.94° ± 5.23°, P = .013) 3 weeks after surgery. However, at 6 weeks, there were no significant differences in external and internal rotation between the 2 groups. In the biomechanical analysis, no significant differences in gross examination (3 weeks, P = .175, 6 weeks, P = .295), load to failure (3 weeks, P = .117, 6 weeks, P = .295), or ultimate stress (3 weeks, P = .602, 6 weeks, P = .917) were noted between the 2 groups 3 and 6 weeks after surgery. In the histological analysis of tendon healing, no significant differences in the total score (3 weeks, P = .323, 6 weeks, P = .572) were found between the 2 groups 3 and 6 weeks after surgery.

CONCLUSIONS

Topical TXA administration showed a beneficial effect in reducing tendon adhesions and improving ROM 3 weeks postoperatively and had no effect at 6 weeks. This suggests that additional intervention with TXA may be useful in achieving long-term improvement in shoulder stiffness. Additionally, TXA may increase tissue ground substance accumulation in the late postoperative period but does not adversely affect tendon-bone interface healing.

CLINICAL RELEVANCE

The use of TXA after rotator cuff repair has no effect on tendon-bone interface healing in clinical practice and can improve shoulder stiffness in the early postoperative period. Additional research on the long-term effects is needed.

Current Research on the Influence of Statin Treatment on Rotator Cuff Healing

Rotator cuff tears are a condition characterized by damage to the muscles and tendons that connect the scapula and humerus, which are responsible for shoulder rotation and arm lifting. Metabolic factors such as diabetes, thyroid disease, high cholesterol, vitamin D deficiency, obesity, and smoking have been associated with an increased risk of rotator cuff tears. Interestingly, patients with hyperlipidemia, a condition characterized by high levels of cholesterol and other fats in the blood, have been found to have a higher incidence of rotator cuff tears and breakdown of tendon matrix. As a result, statin therapy, which is commonly used to lower cholesterol levels in hyperlipidemia, has been explored as a potential treatment to improve clinical outcomes in rotator cuff tears. However, the results of preclinical and clinical studies on the effects of statins on tendon healing in rotator cuff tears are limited and not well-defined. Moreover, since hyperlipidemia and rotator cuff tears are more prevalent in older individuals, a literature review on the efficacy and safety of statin therapy in this population is needed.

Superior capsular reconstruction for irreparable rotator cuff tear: a review of current methods

Irreparable massive rotator cuff tears can significantly impact daily life; and these types of tears can be difficult to repair completely, especially in younger patients who are more active and have higher functional requirements. Since its introduction by Mihata and the colleagues, superior capsular reconstruction (SCR) has gained popularity in the treatment of irreparable massive rotator cuff tears and has shown promising short-term results. A variety of studies have focused on the clinical and biomechanical outcomes of this procedure. This article reviews the biomechanics, indications for the surgical procedure, graft options, surgical technique, and rehabilitation from SCR.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

III.

Metformin increases the expression of proinflammatory cytokines and inhibits supraspinatus fatty infiltration

BACKGROUND

After a rotator cuff (RC) tendon tear, the supraspinatus (SS) inflammatory response induces fatty infiltration (FI). Metformin has the effect of regulating the initial inflammatory response of atrophic muscles. Therefore, this study aimed to investigate the effect of metformin use on modulating the expression of proinflammatory cytokines and SS FI in an acute RC tear rat model.

METHODS

This study used 26 male Sprague-Dawley rats. Animals were randomly divided into two groups: The metformin group received metformin for 5 days after cutting the RC tendon, and the control group was administered only with saline after cutting the tendon. Metformin 50 mg/kg was intraperitoneally injected for 5 days. Three rats in each group were sacrificed 5 days after SS tendon rupture surgery, and 10 rats in each group were sacrificed 14 days after surgery. The SS was sampled 5 days after SS tendon tear surgery, and the expression of proinflammatory cytokines was measured by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). On day 14 after sampling, histological analysis of the SS was performed using hematoxylin and eosin, Masson's trichrome, and picrosirius red staining.

RESULTS

On day 5 of surgery, the expression values of interferon gamma (increased 7.2-fold, P < .01), tumor necrosis factor alpha (increased 13-fold, P < .05), interleukin-1β (increased 4.7-fold, P < .001), and interleukin-6 (increased 4.6-fold, P < .01) increased significantly in the metformin group compared with those in the control group. As a result of Oil Red O staining, SS FI was significantly suppressed in the metformin group compared with that in the control group (metformin group, 305 ± 50.3 µm2, P < .001; control group, 3136 ± 662.8 µm2, P < .001). In addition, the SS volume of the metformin group was not reduced compared with those of the control group, and the morphology and structure of the SS were better preserved.

CONCLUSIONS

The results of this study revealed that metformin can increase the expression of proinflammatory cytokines and suppress SS fat infiltration in delayed sutures.

Radius palmar plate removal without carpal tunnel release: correlation between plate position and median nerve symptoms

We aimed to report the clinical results of volar plate removal without carpal tunnel release in patients with late-onset median neuropathy and to evaluate the relationship between plate position and median nerve symptoms. Part I. Twelve consecutive patients with late-onset median neuropathy treated with volar plate removal without carpal tunnel release were enrolled for analysis. Pre- and post-operative Tinel sign, Phalen and Ten test, subjective rating of tingling sensation, Mayo wrist score and Disabilities of the Arm, Shoulder and Hand (DASH) score were collected. Part II. 232 consecutive patients underwent volar plating for distal radius fracture. The relationships between median nerve symptoms and volar plate prominence on the Soong classification, fracture classification, gender and age were investigated. All cases except one showed complete symptom resolution at final follow-up, with negative Tinel sign and Ten test score of 10/10. Tingling was rated 0 at final follow-up. Mean Mayo wrist and DASH scores improved to 86.7 and 23.1, respectively. The incidence of the median nerve symptoms in our cohort was 5.6%. Even though the odds ratio in Soong grade 2 was 4.0957 (95% CI, 0.93-16.9) compared to the combination of grades 0 and 1, no statistically significant relationship was found between the median nerve symptoms and volar plate prominence (p > 0.05). Plate removal without carpal tunnel release adequately relieved symptoms of late-onset median neuropathy after volar plating in patients with distal radius fracture. Level of Evidence: IV; Therapeutic.

Automated 3-dimensional MRI segmentation for the posterosuperior rotator cuff tear lesion using deep learning algorithm

INTRODUCTION

Rotator cuff tear (RCT) is a challenging and common musculoskeletal disease. Magnetic resonance imaging (MRI) is a commonly used diagnostic modality for RCT, but the interpretation of the results is tedious and has some reliability issues. In this study, we aimed to evaluate the accuracy and efficacy of the 3-dimensional (3D) MRI segmentation for RCT using a deep learning algorithm.

METHODS

A 3D U-Net convolutional neural network (CNN) was developed to detect, segment, and visualize RCT lesions in 3D, using MRI data from 303 patients with RCTs. The RCT lesions were labeled by two shoulder specialists in the entire MR image using in-house developed software. The MRI-based 3D U-Net CNN was trained after the augmentation of a training dataset and tested using randomly selected test data (training: validation: test data ratio was 6:2:2). The segmented RCT lesion was visualized in a three-dimensional reconstructed image, and the performance of the 3D U-Net CNN was evaluated using the Dice coefficient, sensitivity, specificity, precision, F1-score, and Youden index.

RESULTS

A deep learning algorithm using a 3D U-Net CNN successfully detected, segmented, and visualized the area of RCT in 3D. The model's performance reached a 94.3% of Dice coefficient score, 97.1% of sensitivity, 95.0% of specificity, 84.9% of precision, 90.5% of F1-score, and Youden index of 91.8%.

CONCLUSION

The proposed model for 3D segmentation of RCT lesions using MRI data showed overall high accuracy and successful 3D visualization. Further studies are necessary to determine the feasibility of its clinical application and whether its use could improve care and outcomes.

Effects of a graphene oxide-alginate sheet scaffold on rotator cuff tendon healing in a rat model

BACKGROUND

Natural polymer scaffolds used to promote rotator cuff healing have limitations in terms of their mechanical and biochemical properties. This animal study aimed to investigate the effects of combined graphene oxide (GO) and alginate scaffold and the toxicity of GO on rotator cuff healing in a rat model.

METHODS

First, the mechanical properties of a GO/alginate scaffold and a pure alginate scaffold were compared. The in vitro cytotoxicity of and proliferation of human tenocytes with the GO/alginate scaffold were evaluated by CCK-8 assay. For the in vivo experiment, 20 male rats were randomly divided into two groups (n = 10 each), and supraspinatus repair was performed: group 1 underwent supraspinatus repair alone, and group 2 underwent supraspinatus repair with the GO/alginate scaffold. Biomechanical and histological analyses were performed to evaluate the quality of tendon-to-bone healing 8 weeks after rotator cuff repair.

RESULTS

The GO/alginate scaffold exhibited an increased maximum load (p = .001) and tensile strength (p = .001). In the cytotoxicity test, the cell survival rate with the GO/alginate scaffold was 102.08%. The proliferation rate of human tenocytes was no significant difference between the GO/alginate and alginate groups for 1, 3, 5, and 7 days. Biomechanically, group 2 exhibited a significantly greater ultimate failure load (p < .001), ultimate stress (p < .001), and stiffness (p < .001) than group 1. The histological analysis revealed that the tendon-to-bone interface in group 2 showed more collagen fibers bridging, tendon-to-bone integration, longitudinally oriented collagen fibers, and fibrocartilage formation than in group 1.

CONCLUSION

A small amount of GO added to alginate improved the mechanical properties of the scaffold without evidence of cytotoxicity. At 8 weeks after rotator cuff repair, the GO/alginate scaffold improved tendon-to-bone healing without causing any signs of toxicity in a rat model.

Increased interleukin-6 and TP53 levels in rotator cuff tendon repair patients with hypercholesterolemia

Background: A previous study reported that hyperlipidemia increases the incidence of tears in the rotator cuff tendon and affects healing after repair. The aim of our study was to compare the gene and protein expression of torn rotator cuff tendons in patients both with and without hypercholesterolemia. Methods: Thirty patients who provided rotator cuff tendon samples were classified into either a non-hypercholesterolemia group (n=19, serum total cholesterol [TC] <200 mg/dL) and hypercholesterolemia group (n=11, serum TC ≥240 mg/dL) based on their concentrations of serum TC. The expression of various genes of interest, including COL1A1, IGF1, IL-6, MMP2, MMP3, MMP9, MMP13, TNMD, and TP53, was analyzed by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). In addition, western blot analysis was performed on the proteins encoded by interleukin (IL)-6 and TP53 that showed significantly different expression levels in real-time qRT-PCR. Results: Except for IGF1, the gene expression levels of IL-6, MMP2, MMP9, and TP53 were significantly higher in the hypercholesterolemic group than in the non-hypercholesterolemia group. Western blot analysis confirmed significantly higher protein levels of IL-6 and TP53 in the hypercholesterolemic group (p<0.05).Conclusions: We observed an increase in inflammatory cytokine and matrix metalloproteinase (MMP) levels in hypercholesterolemic patients with rotator cuff tears. Increased levels of IL-6 and TP53 were observed at both the mRNA and protein levels. We suggest that the overexpression of IL-6 and TP53 may be a specific feature in rotator cuff disease patients with hypercholesterolemia.

Comparison of the Characteristics of Rotator Cuff Tissue in a Diabetic Rat Model

This study evaluated the biomechanical and histologic characteristics of the rotator cuff tendon and muscle tissue with rat models with diabetes mellitus (DM) (group 1) and 30 male rats without DM (group 2). We conducted a time zero study without any additional procedures or external variables at 9 weeks after induction of the diabetic rat model. Thereafter, quantitative evaluation of advanced glycation end products (AGEs) was accomplished via enzyme-linked immunosorbent assay and immunohistochemistry (IHC). Fatty infiltration was investigated with Oil Red O staining, and the peroxisome proliferator activated receptor-gamma (PPAR-gamma) value was studied with IHC. Grossly, the supraspinatus tendons of the group 1 rats were more friable and discolored (yellowish) than those of group 2. In the biomechanical analysis, group 1 rats showed significantly inferior ultimate failure load (P=.001) and ultimate stress (P=.02). Group 1 was significantly inferior to group 2 in terms of total histologic scoring (P<.001). Mean AGE levels were significantly higher in group 1 (P<.001), as determined by IHC. In evaluating fatty infiltration, the degree of Oil Red O staining was significantly higher in group 1 (P<.001), but there was no significant difference in PPAR-gamma value between the 2 groups (P=.14). The intact rotator cuffs of rats with DM were associated with inferior biomechanics in association with AGE accumulation and increased fatty infiltration, as confirmed by histologic examination The hyperglycemic state caused by DM is associated with rotator cuff tendon degeneration. [Orthopedics. 2022;45(3):e154-e161.].

Improvement in scapular dyskinesis after rotator cuff repair and subacromial decompression

PURPOSE

To investigate the incidence of scapular dyskinesis (SD) in patients with rotator cuff tears using pre- and postoperative 3D computed tomography, analyze the changes in scapular kinematics that occur after arthroscopic rotator cuff repair, and identify the contributing clinical factors.

METHODS

Thirty-five patients (mean age, 62.5 ± 8.4 years) were included. Four scapular angles (upward rotation, internal rotation, protraction, and posterior tilt) were measured. The patients were categorized into three pre-existing SD types according to the difference in measured scapular angles between the affected and unaffected sides (type 1 SD, posterior tilt angle difference <  - 5°; type 2 SD, internal rotation angle difference > 5°; and type 3 SD, upward rotation angle difference > 5°). The prevalence, factors influencing SD, and outcomes were compared between the improved and sustained SD groups.

RESULTS

Twenty three of the 35 patients (65.7%) with rotator cuff tears had SD (type 1, 11; type 2, six; type 3, six). Of the 23 preoperative SD patients, 12 (52.1%) showed improved SD postoperatively. Most of the patients with improved SD (9/12) had type 1 SD (p = 0.021) and a significantly improved posterior tilt angle (p = 0.043). The improvement in SD was correlated with a higher range of motion of forward flexion and higher Constant scores (all p < 0.05). No healing failure occurred in the improved SD group (p = 0.037).

CONCLUSION

The prevalence of SD was high in patients with degenerative rotator cuff tears. More than half of the SD cases, especially type 1 SD, improved postoperatively. SD recovery correlated with better function and successful rotator cuff healing.

LEVEL OF EVIDENCE

IV.

Effect of a Porous Suture Containing Transforming Growth Factor Beta 1 on Healing After Rotator Cuff Repair in a Rat Model

BACKGROUND

The healing failure rate after rotator cuff repair is considerably high.

PURPOSE

To evaluate the effect of a porous suture containing transforming growth factor beta 1 (TGF-β1) on the sustained release of TGF-β1 and rotator cuff healing in a rat model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A porous suture was developed, and its tensile strength was measured. TGF-β1 was delivered using the porous suture, and a TGF-β1 release test and human fibroblast proliferation assay were performed. For the animal experiment, 30 rats were randomly allocated into 3 groups (n = 10 each). A bilateral supraspinatus tendon tear was made in all the rats, and repair was performed. Group 1 received repair only; group 2, repair and a single injection of TGF-β1; and group 3, repair using the porous suture containing TGF-β1. Eight weeks after repair, biomechanical and histological analyses were performed.

RESULTS

The porous suture was successfully developed with mechanical properties compatible with the conventional suture, and the sustained release of TGF-β1 from the porous suture was confirmed. In addition, the cell proliferation assay confirmed the biological safety of the porous suture. In the animal experiment, group 3 biomechanically exhibited the largest cross-sectional area and the highest ultimate failure load and ultimate stress (all P < .05). Histological examination revealed that group 3 showed significantly better collagen fiber density and tendon-to-bone maturation than did groups 1 and 2 (all P < .05).

CONCLUSION

The porous suture containing TGF-β1 could sustainedly and safely release TGF-β1, and its use during rotator cuff repair could improve rotator cuff healing, as assessed on the basis of the biomechanical and histological changes in the rat model in this study. Considering the effectiveness, safety, and convenience of the porous suture without extra effort in surgery, the findings of the present study will have a far-reaching effect on the treatment of rotator cuff tears.

CLINICAL RELEVANCE

The porous suture containing TGF-β1 might improve healing after rotator cuff repair.

The best options in superior capsular reconstruction

Irreparable massive rotator cuff tears cause pain, loss of function, and a decrease in range of motion, which cause serious disturbances in daily life. Young patients, in particular, are active and have relatively high functional requirements, and their surgical options are limited. Superior capsular reconstruction (SCR) was first proposed for irreparable massive rotator cuff tears, good clinical results have been reported in short-term follow up. Since then, SCR has been used increasingly worldwide for irreparable massive rotator cuff tears, and various studies have been published on clinical outcomes, biomechanical outcomes, surgical techniques, and graft types. This article reviews the optimal graft and surgical options for improving clinical outcomes in SCR.

Clinical outcome of rotator cuff repair in patients with mild to moderate glenohumeral osteoarthritis

PURPOSE

Osteoarthritis (OA) in the glenohumeral joint is a concomitant lesion with rotator cuff tear that commonly occurs in older patients. The authors aimed to evaluate the effect of associated OA on the treatment outcome of rotator cuff repair.

METHODS

A total of three hundred and forty-eight patients who underwent full-thickness arthroscopic rotator cuff repair were retrospectively reviewed, and the data were prospectively collected. The severity of OA was evaluated using the Samilson and Prieto method preoperatively and the Outerbridge classification intraoperatively. The patients were divided into the small-to-medium group and large-to-massive group according to rotator cuff tear size and were evaluated for presence or absence of OA. The postoperative clinical outcomes were assessed using the visual analog scale for pain, simple shoulder test (SST), University of California-Los Angeles, Constant, and American Shoulder and Elbow Surgeons (ASES) scoring systems at baseline and at final follow-up.

RESULTS

Forty-five patients were diagnosed with glenohumeral OA (12.9%). Overall, no significant differences were observed in demographic and baseline data between the two groups according to the presence or absence of OA. The clinical symptoms of both groups significantly improved at the final follow-up. At the final follow-up, no significant differences were found in the VAS for pain, SST, UCLA, Constant, and ASES scores between the two groups. In the large-to-massive tear group, patients with OA had significantly inferior clinical results compared with those without OA.

CONCLUSION

The clinical outcome scores improved after rotator cuff repair regardless of the presence of concomitant OA. However, glenohumeral OA should be considered as a potential negative prognostic factor in patients with large-to-massive rotator cuff tears.

LEVEL OF EVIDENCE

III.

Automated rotator cuff tear classification using 3D convolutional neural network

Rotator cuff tear (RCT) is one of the most common shoulder injuries. When diagnosing RCT, skilled orthopedists visually interpret magnetic resonance imaging (MRI) scan data. For automated and accurate diagnosis of RCT, we propose a full 3D convolutional neural network (CNN) based method using deep learning. This 3D CNN automatically diagnoses the presence or absence of an RCT, classifies the tear size, and provides 3D visualization of the tear location. To train the 3D CNN, the Voxception-ResNet (VRN) structure was used. This architecture uses 3D convolution filters, so it is advantageous in extracting information from 3D data compared with 2D-based CNNs or traditional diagnosis methods. MRI data from 2,124 patients were used to train and test the VRN-based 3D CNN. The network is trained to classify RCT into five classes (None, Partial, Small, Medium, Large-to-Massive). A 3D class activation map (CAM) was visualized by volume rendering to show the localization and size information of RCT in 3D. A comparative experiment was performed for the proposed method and clinical experts by using randomly selected 200 test set data, which had been separated from training set. The VRN-based 3D CNN outperformed orthopedists specialized in shoulder and general orthopedists in binary accuracy (92.5% vs. 76.4% and 68.2%), top-1 accuracy (69.0% vs. 45.8% and 30.5%), top-1±1 accuracy (87.5% vs. 79.8% and 71.0%), sensitivity (0.92 vs. 0.89 and 0.93), and specificity (0.86 vs. 0.61 and 0.26). The generated 3D CAM provided effective information regarding the 3D location and size of the tear. Given these results, the proposed method demonstrates the feasibility of artificial intelligence that can assist in clinical RCT diagnosis.

Atrogin1-induced loss of aquaporin 4 in myocytes leads to skeletal muscle atrophy

The water channel aquaporin 4 (AQP4) regulates the flux of water across the cell membrane, maintaining cellular homeostasis. Since AQP4 is enriched in the sarcolemma of skeletal muscle, a functional defect in AQP4 may cause skeletal muscle dysfunction. To investigate a novel mechanism underlying skeletal muscle atrophy, we examined AQP4 expression and its regulation in muscle using the rotator cuff tear (RCT) model. Human and mouse AQP4 expression was significantly decreased in atrophied muscle resulting from RCT. The size and the number of myotubes were reduced following AQP4 knockdown. Atrogin 1-mediated ubiquitination of AQP4 was verified with an ubiquitination assay after immunoprecipitation of AQP4 with an anti-AQP4 antibody. In this study, we identified high mobility group box 1 (HMGB1) as a potent upstream regulator of atrogin 1 expression. Atrogin 1 expression was increased by recombinant mouse HMGB1 protein, and the HMGB1-induced atrogin 1 expression was mediated via NF-κB signaling. Our study suggests that loss of AQP4 appears to be involved in myocyte shrinkage after RCT, and its degradation is mediated by atrogin 1-dependent ubiquitination. HMGB1, in its function as a signaling molecule upstream of the ubiquitin ligase atrogin 1, was found to be a novel regulator of muscle atrophy.

Concomitant Coracoid Process Fracture with Bony Bankart Lesion Treated with the Latarjet Procedure

Bony lesions of the glenoid and Hill-Sachs lesions are the most common injuries after a first-time traumatic shoulder dislocation. However, fracture of the coracoid process after traumatic shoulder dislocation is rare. A single, open surgical procedure could be performed by a Latarjet procedure using a fractured fragment of the coracoid process. If a fracture of the coracoid process is associated with a traumatic anterior shoulder dislocation, the Latarjet procedure may be the most appropriate surgical option.

Is a Local Administration of Parathyroid Hormone Effective to Tendon-to-Bone Healing in a Rat Rotator Cuff Repair Model?

To evaluate the effect of local parathyroid hormone (PTH) administration on rotator cuff tendon-to-bone healing in a rat model compared with systemic PTH injection and untreated controls. PTH-alginate scaffold was prepared and sustained release of PTH was confirmed. Bilateral supraspinatus tendon repairs were performed in 39 rats (group 1, supraspinatus repair only; group 2, supraspinatus repair with systemic PTH injection; group 3, supraspinatus repair with local PTH administration via an absorbable scaffold; n = 13 each). Biomechanical (cross-sectional area, mode of failure, load to failure, and ultimate stress: right side) and histological analyses (hematoxylin and eosin stain, Masson's Trichrome stain Picrosirius red stain, Immunohistochemistry for BMP2, PTH1R, ColI, and ColIII: Left side) were performed to evaluate tendon-to-bone healing quality at 8 weeks after repair, and blood test (osteocalcin and procollagen type I N-terminal pro-peptide [PINP] levels) was performed in all rats. There was no intergroup difference in the healing failure rate (p = 0.910) or failure mode (p = 0.585). Biomechanically, subjects in groups 2 and 3 exhibited significantly larger cross-sectional areas and higher ultimate failure loads and ultimate stress than those in group 1 (all p < 0.05); however, no differences were noted between groups 2 and 3 (all p > 0.05). Histologically, groups 2 and 3 exhibited more organized tendon-to-bone interface structures with higher density, parallel orientation, and collagen fiber continuity than group 1 (all p < 0.05 except collagen fiber continuity in group 1 vs. 2); however, no differences in histological parameters between groups 2 and 3 (all p > 0.05). The protein levels of bone morphogenic protein 2, PTH 1 receptor, and collagen I and III and the serum level of PINP were increased in groups 2 and 3 versus group 1 (all p < 0.05) without showing differences between groups 2 and 3 (all p > 0.05). Local PTH administration using an absorbable scaffold improved the biomechanical and histological outcomes of rotator cuff tendon-to-bone healing comparable with systemic PTH injection at 8 weeks after repair in a rat model. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:82-91, 2020.

Does strength deficit correlate with shoulder function in patients with rotator cuff tears? Characteristics of massive tears

BACKGROUND

The correlation between shoulder strength deficits and function in rotator cuff tears remains uncertain. This study aimed to determine the correlation between shoulder strength deficits and shoulder function evaluated by various clinical scoring systems.

METHODS

A total of 262 patients (mean age, 59.67 years [standard deviation, 8.06 years]) who underwent full-thickness rotator cuff repair were included. Patients in group I (n = 188) had small to large rotator cuff tears, whereas those in group II (n = 74) had massive rotator cuff tears. Demographic factors, isokinetic test results, and shoulder function evaluated using various scoring systems were obtained. Correlation differences according to severity of the rotator cuff tear were evaluated.

RESULTS

We found weak correlations between shoulder strength deficits (peak torque and total work) and clinical outcomes in patients with rotator cuff tears (r = -0.288). For patients in group I (nonmassive tears), we found a weaker correlation (r = -0.242) according to the tear pattern. However, shoulder strength deficits in group II patients (massive tears) were strongly correlated with American Shoulder and Elbow Surgeons (r = -0.598), Constant (r = -0.582), and Short Form 36 (r = -0.511) scores, especially regarding internal rotator strength deficits.

CONCLUSIONS

Shoulder strength deficits measured via isokinetic testing and shoulder function were weakly correlated in patients with rotator cuff tears. However, shoulder strength deficits in patients with massive tears considerably worsened shoulder function and systemic disability, but not regional disability. In particular, internal rotator strength deficits were strongly correlated with poor shoulder function.

Factors associated with needle breakage of antegrade suture passer and effect of intratendinous remnant needle tip on clinical outcomes after arthroscopic rotator cuff repair

Objective

The aim of this study was to evaluate factors associated with the needle breakage of antegrade suture passer and the effect of intratendinous remnant needle tip on clinical outcomes after rotator cuff repair.

Methods

We retrospectively reviewed 283 patients (138 men and 145 women; mean age: 59.7 ± 9.3 years) who underwent arthroscopic repair for full-thickness rotator cuff tear. We evaluated the characteristics of 16 patients in whose needle tip had been broken and embedded and remained in the rotator cuff (remnant needle group) and compared them with the remaining 267 patients (control group). Afterwards, another 64 patients were selected from control group (1:4 matching) after propensity score matching (PSM). The groups were compared anatomically with MRI or ultrasonography and functionally (serial pain VAS and ROM; ASES, Constant, UCLA and SST scores) at a minimum follow-up of 1 year.

Results

The remnant needle group showed preoperative thicker tendon (6.72 mm vs 5.33 mm, p = 0.047), higher tendinosis (mean grade, 1.88 vs. 1.43, p = 0.029), and more frequent delaminated tears (p = 0.035) compared with control group. When we compare the clinical outcomes after PSM, the initial pain VAS of the remnant needle tip group was higher up to 3 months (pain VAS: 4.13 ± 2.07 vs 2.48 ± 1.61 (p = 0.032) at 5 weeks and 3.79 ± 2.12 vs 2.25 ± 1.76 (p = 0.044) at 3 months), however the difference disappeared after 6 months postoperatively. In final evaluation, there was no significant differences in every outcome parameters (all p > 0.05).

Conclusion

Breakage of the needle of the antegrade suture passer occurred more frequently in the thicker tendon, higher tendinosis, and delaminated tears. The retained broken needle tip was associated with higher pain scores during the early postoperative period, but revealed no difference in final outcomes by using PSM.

Level of Evidence

Level III, Therapeutic Study

Patient-specific Guides Using 3-dimensional Reconstruction Provide Accuracy and Reproducibility in Reverse Total Shoulder Arthroplasty

Background

We aimed to evaluate whether the use of our novel patient-specific guide (PSG) with 3-dimensional reconstruction in reverse total shoulder arthroplasty (RTSA) would allow accurate and reliable implantation of the glenoid and humeral components.

Methods

20 fresh-frozen cadaveric shoulders were used. The PSG group (n=10) and conventional group (n=10) was evaluated the accuracy and reproducibility of implant positioning between before and after surgery on the computed tomography image.

Results

The superoinferior and anteroposterior offset in the glenoid component were 0.42 ± 0.07, 0.50 ± 0.08 in the conventional group and 0.45 ± 0.03, 0.46 ± 0.02 in the PSG group. The inclination and version angles were -1.93° ± 4.31°, 2.27° ± 5.91° and 0.46° ± 0.02°, 3.38° ± 2.79°. The standard deviation showed a smaller difference in the PSG group. The anteroposterior and lateromedial humeral canal center offset in the humeral component were 0.45 ± 0.12, 0.48 ± 0.15 in the conventional group and 0.46 ± 0.59 (p=0.794), 0.46 ± 0.06 (p=0.702) in the PSG group. The PSG showed significantly better humeral stem alignment.

Conclusions

The use of PSGs with 3-dimensional reconstruction reduces variabilities in glenoid and humerus component positions and prevents extreme positioning errors in RTSA.

Synchronization of Synovial Chondromatosis and Mycobacterium intracellurae Infection in Olecranon Bursitis: A Case Report

A 73-year-old woman presented with a recurrent cystic mass around her left olecranon. She had a history of 8 steroid injections due to elbow pain beginning 3 years ago and twice had undergone aspiration of olecranon bursitis that developed two months prior to presentation. She had been taking medications for hypertension and diabetes with no pertinent past history. On magnetic resonance imaging (MRI), there were multiple nodules in the olecranon bursa, which were isointense to muscle on T1-weighted images and hyperintense to muscle on T2-weighted images. Our initial diagnosis was synovial chondromatosis. On bursoscopy, masses of gray-white colored nodules were observed in the bursa. Finally, synovial chondromatosis and non-tuberculous mycobacterial infection were concurrently diagnosed. In conclusion, uncalcified synovial chondromatosis and rice bodies can have similar visual and MRI characteristics; therefore, we suggest that clinicians should be aware of the possibility of other infections in cases of this type.

Mechanical Augmentation With Absorbable Alginate Sheet Enhances Healing of the Rotator Cuff

For anatomical restoration of a repaired rotator cuff, mechanical augmentation of the repaired structure is essential. Using histological and biomechanical evaluation in a rat model, the authors sought to determine the efficacy of an absorbable alginate sheet at the supraspinatus tendon-to-bone repair site for healing of the rotator cuff tear. Forty adult (12 weeks old) male Sprague- Dawley wild-type rats were used in this study. The animals were randomly separated into 2 groups: group 1, conventional supraspinatus repair with acute repair; or group 2, supraspinatus repair with absorbable alginate sheet. Biomechanical and histological analyses were performed at 6 and 12 weeks after index rotator cuff surgery. Compared with group 1, group 2 exhibited a significantly greater mean ultimate failure load (group 1, 23.70±3.87 N; group 2, 61.44±43.67 N; P=.023) and mean ultimate stress (group 1, 2.83±0.50 MPa; group 2, 7.36±2.87 MPa; P=.020). However, 6-week outcomes were not significantly different. On histological scoring, compared with group 1, group 2 exhibited a significantly greater mean 6-week score (group 1, 4.10±1.72 points; group 2, 7.80±1.47 points; P<.001) and mean 12-week score (group 1, 3.50±1.00 points; group 2, 5.25±2.62 points; P=.020). Mechanical augmentation with absorbable alginate may improve tendon healing after surgical repair of the rotator cuff. [Orthopedics. 2019; 42(1):e104-e110.].

Changes in Perianchor Cyst Formation Over Time After Rotator Cuff Repair: Influential Factors and Outcomes

BACKGROUND

There is a lack of knowledge about the changes in perianchor cysts over time and the factors related to perianchor cysts.

PURPOSE

To evaluate the changes in perianchor cyst formation and anchor absorption over time after arthroscopic rotator cuff repair with a biocomposite suture anchor and to evaluate the factors affecting perianchor cyst persistence and their relationship with patient outcomes.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Forty consecutive patients (mean age, 61.10 ± 5.79 years) who underwent arthroscopic repair for medium- to large-sized rotator cuff tears using a single type of biocomposite (poly-L-lactic acid/polyglycolic acid-beta tricalcium phosphate) medial-row anchor were prospectively enrolled. Postoperative magnetic resonance imaging (MRI) at 2 different time points (6 and 18 months) was performed, and perianchor cyst formation, anchor absorption, and healing failures were evaluated using postoperative MRI. Demographic and clinical data were collected, and functional outcomes at a minimum of 18 months after surgery were assessed.

RESULTS

Perianchor cysts were observed in 24 patients (60.0% total; grade 1: 35.0%; grade 2: 10.0%; grade 3: 7.5%; grade 4: 7.5%) at 6 months, and 7 patients (18.4% total; grade 1: 7.9%; grade 2: 5.3%; grade 3: 2.6%; grade 4: 2.6%) had a persistent perianchor cyst at 18 months after surgery. No anchors were absorbed at 6 months, but 73.7% of patients revealed complete or near-full absorption at 18 months. Patients with persistent perianchor cysts showed a significantly larger tear size in the anteroposterior dimension ( P = .002) and greater retraction ( P < .001). There were no differences in healing failures and functional outcomes between patients with and without persisting perianchor cysts (all P > .05). No differences were found in perianchor cyst formation and anchor absorption between anchors inserted in the greater tuberosity and the lesser tuberosity (all P > .05).

CONCLUSION

The incidence and severity of perianchor cysts decreased with time, and most biocomposite suture anchors were absorbed at 18 months after surgery. Persisting perianchor cysts correlated with a larger tear size in the anteroposterior dimension and greater retraction.

Posteromedial Elbow Dislocations without Relevant Osseous Lesions: Clinical Characteristics, Soft-Tissue Injury Patterns, Treatments, and Outcomes

BACKGROUND

Although simple posterolateral or posterior elbow dislocations are relatively common and usually stable after closed reduction, simple posteromedial dislocations are extremely rare and poorly characterized. We investigated the clinical characteristics, soft-tissue injury patterns, treatments, and outcomes of a series of posteromedial elbow dislocations without relevant osseous lesions.

METHODS

We retrospectively reviewed 20 cases of simple posteromedial elbow dislocations without relevant osseous lesions that were treated at 7 fellowship training hospitals during a 10-year period. Soft-tissue injury patterns in 15 cases were investigated with use of magnetic resonance imaging. Clinical outcomes were evaluated after an average of 56.1 months (range, 24 to 93 months) with use of the Mayo Elbow Performance Score (MEPS) and the Quick-DASH (an abbreviated version of the Disabilities of the Arm, Shoulder and Hand [DASH]) score. Complications were also evaluated.

RESULTS

On magnetic resonance imaging, significant tears of the lateral collateral ligament complex and common extensor group were observed in all cases. Seventeen cases (85%) required surgical treatment for acute instability. Fourteen cases underwent only lateral complex repair and 3 underwent repair of both the medial and lateral complexes. At the time of the latest follow-up, the mean MEPS and Quick-DASH scores were 85.8 ± 15.0 and 10.5 ± 16.3, respectively. Seventeen patients (85%) had a satisfactory clinical outcome. Complications following treatment included 4 patients with heterotopic ossification; 2 of these patients also experienced posttraumatic elbow stiffness, which was treated with arthrolysis at 8 and 18 months after the initial operation.

CONCLUSIONS

Posteromedial elbow dislocations without relevant osseous lesions are associated with a more severe soft-tissue injury, especially to the lateral complex, resulting in a high rate of surgical treatment. With careful post-reduction evaluation, either operative or nonoperative treatment provided satisfactory clinical outcomes.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Effect of Smoking on Healing Failure After Rotator Cuff Repair

BACKGROUND

No study to date has directly evaluated rotator cuff repair results among smokers.

PURPOSE

To evaluate whether smoking affects healing after arthroscopic rotator cuff repair through propensity score matching (PSM).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Among 249 patients who underwent arthroscopic repair of full-thickness rotator cuff tears, 34 current heavy smokers were selected with a smoking history >20 pack-years (mean ± SD pack-years, 33.91 ± 12.13). Characteristics between current heavy smokers and nonsmokers were compared. According to the PSM technique, 34 nonsmokers were selected after 1:1 matching for age, fatty infiltration, and tear size-the main prognostic factors of outcomes after rotator cuff repair. Each patient's outcome evaluation was completed anatomically at a minimum of 6 months (magnetic resonance imaging or ultrasonography) and functionally at a minimum of 1 year (pain visual analog scale, range of motion, American Shoulder and Elbow Surgeons, Constant, University of California, Los Angeles, and Simple Shoulder Test scores), and every outcome was analyzed in the matched smoker and nonsmoker groups.

RESULTS

Current heavy smokers had a higher incidence of male sex ( P < .001), heavy manual work ( P = .025), high bone density ( P = .036), and poor tendinosis grade ( P = .028). After adjustment for the confounding variables by PSM, the matched smoker group showed a significantly higher healing failure rate than the matched nonsmoker group (29.4% vs 5.9%, P = .023). However, we failed to detect significant differences in the functional outcomes between the matched groups ( P > .05).

CONCLUSION

Smoking affected healing failure after arthroscopic rotator cuff repair. Attention should be paid to smokers, especially current heavy smokers, in cases of rotator cuff repair surgery.

A Comparison of Clinical and Radiological Outcomes of Minimally Invasive and Conventional Plate Osteosynthesis for Midshaft Clavicle Fractures

Thirty patients with displaced midshaft clavicle fractures were prospectively enrolled in this study. Fifteen were randomly assigned to the minimally invasive plate osteosynthesis group and 15 to the conventional plate osteosynthesis group. Constant score, visual analog scale satisfaction score, operative time, scar length, and complications, including hypoesthesia, were evaluated at least 1 year postoperatively to determine functional outcomes and time to bone union as a radiological outcome. Factors related to bone union, including the gap interval between fracture fragments and the number of fracture fragments, were also evaluated. The Constant score and the visual analog scale satisfaction score were higher in the minimally invasive plate osteosynthesis group than in the conventional plate osteosynthesis group; however, there was no significant difference between the groups in these scores or in the time to bone union (all P>.05). Hypoesthesia was the only complication, and its incidence was not different between the groups (P=.249). However, operative time (52.33±13.87 vs 110.33±25.39 minutes, P<.001) and scar length (64.95±3.19 vs 99.39±15.98 mm, P<.001) were significantly shorter in the minimally invasive plate osteosynthesis group than in the conventional plate osteosynthesis group, respectively. In the minimally invasive plate osteosynthesis group, time to bone union was significantly correlated with the gap interval (P=.004) and the number of fracture fragments (P=.002). Minimally invasive plate osteosynthesis showed some superiority over conventional plate fixation for midshaft clavicle fractures, having a shorter operative time and scar length. The time to bone union was influenced by the reduction status and the number of fracture fragments in the minimally invasive plate osteosynthesis group. [Orthopedics. 2018; 41(5):e649-e654.].

Automated detection and classification of the proximal humerus fracture by using deep learning algorithm

Background and purpose - We aimed to evaluate the ability of artificial intelligence (a deep learning algorithm) to detect and classify proximal humerus fractures using plain anteroposterior shoulder radiographs. Patients and methods - 1,891 images (1 image per person) of normal shoulders (n = 515) and 4 proximal humerus fracture types (greater tuberosity, 346; surgical neck, 514; 3-part, 269; 4-part, 247) classified by 3 specialists were evaluated. We trained a deep convolutional neural network (CNN) after augmentation of a training dataset. The ability of the CNN, as measured by top-1 accuracy, area under receiver operating characteristics curve (AUC), sensitivity/specificity, and Youden index, in comparison with humans (28 general physicians, 11 general orthopedists, and 19 orthopedists specialized in the shoulder) to detect and classify proximal humerus fractures was evaluated. Results - The CNN showed a high performance of 96% top-1 accuracy, 1.00 AUC, 0.99/0.97 sensitivity/specificity, and 0.97 Youden index for distinguishing normal shoulders from proximal humerus fractures. In addition, the CNN showed promising results with 65-86% top-1 accuracy, 0.90-0.98 AUC, 0.88/0.83-0.97/0.94 sensitivity/specificity, and 0.71-0.90 Youden index for classifying fracture type. When compared with the human groups, the CNN showed superior performance to that of general physicians and orthopedists, similar performance to orthopedists specialized in the shoulder, and the superior performance of the CNN was more marked in complex 3- and 4-part fractures. Interpretation - The use of artificial intelligence can accurately detect and classify proximal humerus fractures on plain shoulder AP radiographs. Further studies are necessary to determine the feasibility of applying artificial intelligence in the clinic and whether its use could improve care and outcomes compared with current orthopedic assessments.

Clinical and Radiological Results of Hook Plate Fixation in Acute Acromioclavicular Joint Dislocations and Distal Clavicle Fractures

Background

The purpose of this study was to evaluate the clinical outcomes and complications of hook plate fixation in acromioclavicular (AC) joint dislocations and distal clavicle fractures.

Methods

We retrospectively reviewed a series of 60 consecutive patients with hook plate fixation for AC joint dislocation (group I) and distal clavicle fracture (group II). Groups I and II had 39 and 21 patients, respectively. Clinical results were evaluated using the pain visual analogue scale (VAS), simple shoulder test, and Constant-Murley scores. In addition, subacromial erosion and stiffness were evaluated as complications.

Results

At the removal, the pain VAS was 2.69 ± 1.30 and 4.10 ± 2.14 in groups I and II, respectively, which were significantly different (p=0.003). The simple shoulder test score was 9.59 ± 1.60 and 7.81 ± 2.67 in groups I and II, respectively, which were also significantly different (p=0.002). Subacromial erosion was significantly more frequent in group II (14/21 patients, 66.7%) than in group I (15/39 patients, 38.5%) (p=0.037), and stiffness was also higher in group II (17/21 patients, 81.0%) than in group I (22/39 patients, 56.4%), but it was not significant.

Conclusions

Hook plate fixation showed good clinical and functional results for the treatment of acute unstable AC joint dislocation and distal clavicle fracture. But, in distal clavicle fractures, there are more subacromial erosion and stiffness compare with acute unstable AC joint dislocation.

Sustained Delivery of Transforming Growth Factor β1 by Use of Absorbable Alginate Scaffold Enhances Rotator Cuff Healing in a Rabbit Model

BACKGROUND

The failure rate for healing after rotator cuff repair is relatively high.

PURPOSE

To establish a system for sustained release of transforming growth factor β1 (TGF-β1) using an alginate scaffold and evaluate the effects of the sustained release of TGF-β1 on rotator cuff healing in a rabbit model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Before the in vivo animal study, a standard MTS assay was performed to evaluate cell proliferation and metabolic activity on the alginate scaffold. Additionally, an enzyme-linked immunosorbent assay was performed to confirm the capacity of the sustained release of TGF-β1-containing alginate scaffold. Once the in vitro studies were completed, bilateral supraspinatus tendon repairs were performed in 48 rabbits that were allocated to 3 groups (n = 16 each) (group 1, supraspinatus repair only; group 2, supraspinatus repair with TGF-β1 single injection; group 3, supraspinatus repair with TGF-β1 sustained release via an alginate-based delivery system). Biomechanical and histological analyses were performed to evaluate the quality of tendon-to-bone healing at 12 weeks after rotator cuff repair.

RESULTS

The cell proliferation rate of the alginate scaffold was 122.30% compared with the control (fresh medium) group, which confirmed that the alginate sheet had no cytotoxicity and enhanced cell proliferation. Additionally, the level of TGF-β1 was found to increase with time on the alginate scaffold. Biomechanically, group 3 exhibited a significantly heightened ultimate failure load compared with groups 1 and 2 (group 1, 74.89 ± 29.82 N; group 2, 80.02 ± 34.42 N; group 3, 108.32 ± 32.48 N; P = .011) and more prevalent midsubstance tear compared with group 1 ( P = .028). However, no statistical differences were found in the cross-sectional area of the supraspinatus tendon (group 1, 32.74 ± 9.38; group 2, 33.76 ± 8.89; group 3, 34.80 ± 14.52; P = .882) and ultimate stress (group 1, 2.62 ± 1.13 MPa; group 2, 2.99 ± 1.81 MPa; group 3, 3.62 ± 2.24 MPa; P = .317). Histologically, group 3 exhibited a significantly heightened modified total Bonar score (group 1, 5.00 ± 1.54; group 2, 6.12 ± 1.85; group 3, 7.50 ± 1.31; P = .001). In addition, the tendon-to-bone interface for group 3 demonstrated better collagen orientation, continuity, and organization, and the area of new fibrocartilage formation was more evident in group 3.

CONCLUSION

At 12 weeks after rotator cuff repair, the authors found improved biomechanical and histological outcomes for sustained release of TGF-β1 using alginate scaffold in a rabbit model.

CLINICAL RELEVANCE

The alginate-bound growth factor delivery system might improve healing after rotator cuff repair in humans.

Clinical Outcomes of Arthroscopic Rotator Cuff Repair Using Poly Lactic-co-glycolic Acid Plus β-tricalcium Phosphate Biocomposite Suture Anchors

Background

This study is performed to evaluate anchor-related outcomes and complications after arthroscopic rotator cuff repair using 30% β-tricalcium phosphate (β-TCP) with 70% poly lactic-co-glycolic acid (PLGA) biocomposite suture anchors.

Methods

A total of 78 patients (mean age, 61.3 ± 6.9 years) who underwent arthroscopic medium-to-large full-thickness rotator cuff tear repair were enrolled. The technique employed 30% β-TCP with 70% PLGA biocomposite suture anchors at the medial row (38 patients, Healix BR^TM anchor [Healix group]; 40 patients, Fixone anchor B [Fixone group]). The radiologic outcomes (including perianchor cyst formation or bone substitution) and anatomical outcomes of the healing failure rate were evaluated using magnetic resonance imaging at least 6 months after surgery, the pain visual analogue scale at 3, 6 months, and final follow-up visit, and American Shoulder and Elbow Surgeons scores at least 1 year postoperatively. Anchor-related complications were also evaluated.

Results

The perianchor cyst formation incidence was similar for both groups (60.5%, Healix group; 60.0%, Fixone group; p=0.967), although severe perianchor cyst incidence was slightly lower in the Fixone group (15.0%) than in the Healix group (21.1%). There was no occurrence of anchor absorption and bone substitution. No differences were observed in the healing failure rate (13.2%, Healix group; 15.0%, Fixone group; p=0.815) and functional outcome between groups (all p>0.05). Anchor breakage occurred in 5 patients (2 Healix anchors and 3 Fixone anchors); however, there were no major anchor-related complications in either group.

Conclusions

No differences were observed in the clinical outcomes of the Healix and Fixone groups, neither were there any accompanying major anchor-related complications.

Fatty Degeneration of the Rotator Cuff Reflects Shoulder Strength Deficits in Patients With Rotator Cuff Tears

Fatty degeneration is an important clinical factor in patients with rotator cuff tears. Goutallier grade, occupation ratio, and tangent sign help identify fatty degeneration; however, little is known about how closely these measurement techniques correlate with actual muscle strength deficits. The authors evaluated each method's ability to determine the correlation between fatty degeneration and muscle strength deficits. The authors included 203 patients who underwent full-thickness rotator cuff repair (mean age, 61.29±7.92 years). All patients were evaluated with preoperative magnetic resonance imaging to identify fatty degeneration and with an isokinetic test to determine actual shoulder strength. Fatty degeneration was evaluated using Goutallier grade, occupation ratio, and tangent sign. The actual shoulder strength deficit was evaluated by abduction, whereas external and internal rotation were tested using the isokinetic test. More severe fatty degeneration was correlated with lower degrees of abduction, external rotation, and internal rotation. The occupation ratio was more closely correlated with actual muscle strength deficits. However, in patients with massive tears, the correlation between fatty degeneration and muscle strength was less pronounced. Tangent sign (+) findings had a significantly lower strength of external rotation and abduction. The fatty degeneration of the rotator cuff muscle measured by each method was correlated with actual shoulder strength deficits in patients with rotator cuff tears. However, the correlations were less clear in patients with massive rotator cuff tears. Therefore, in cases of massive rotator cuff tears, fatty degeneration was correlated with muscle strength deficits but was not directly proportional to their extent. [Orthopedics. 2018; 41(1):e15-e21.].

Altered Gene and Protein Expressions in Torn Rotator Cuff Tendon Tissues in Diabetic Patients

PURPOSE

To analyze and compare the gene and protein expression characteristics in torn rotator cuff tendon tissues between diabetic and nondiabetic patients.

METHODS

This was a pilot study. Twelve samples of rotator cuff tendon tissue from diabetic patients (mean age, 62.3 ± 9.9 years) and 12 age- and sex-matched nondiabetic tendon tissues (62.3 ± 9.9 years) were acquired from the torn tendon end of medium rotator cuff tears during arthroscopic surgery, after applying the same inclusion and exclusion criteria. Expressions of various genes of interest, including collagens I and III, matrix metalloprotease (MMP)-2, MMP-3, MMP-9, MMP-13, interleukin (IL)-1, IL-6, insulin-like growth factor-1, vascular endothelial growth factor, tenomodulin, tumor necrosis factor-α, and p53, were analyzed with real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). In addition, immunohistochemistry and western blot assay were performed for the genes that revealed significantly different expressions in real-time qRT-PCR between groups.

RESULTS

Gene expression levels of MMP-9, MMP-13, IL-6, and tenomodulin were significantly higher in the diabetic than in the nondiabetic group by real-time qRT-PCR analyses (P = .011, .004, .009, and .010, respectively). The density of cells expressing MMP-9 and IL-6 was significantly increased in the torn tendons of the diabetic patients on immunohistochemical analysis, and the density of MMP-9 and IL-6 protein expressions was significantly higher in the diabetic group on western blot (P = .018 and .044, respectively).

CONCLUSIONS

Diabetic torn cuff tendon tissues showed MMP-9 and IL-6 overexpressions compared with controls.

CLINICAL RELEVANCE

The overexpressions of MMP-9 and IL-6 may be one of the explanations for the high healing failure rate after rotator cuff repair in the diabetic patients.

Outcomes of Combined Bone Marrow Stimulation and Patch Augmentation for Massive Rotator Cuff Tears

BACKGROUND

The high failure rate after surgical repair of massive rotator cuff tears is a consistent problem.

PURPOSE

To evaluate the clinical and radiological outcomes of arthroscopic rotator cuff repair with bone marrow stimulation and patch augmentation in patients with massive rotator cuff tears.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study included 21 patients who underwent bone marrow stimulation and patch augmentation (group 1) and 54 patients who underwent conventional repair (group 2) for massive rotator cuff tears. Postoperative clinical outcomes were evaluated based on visual analog scale (VAS) for pain, simple shoulder test (SST), University of California, Los Angeles (UCLA), Constant, and American Shoulder and Elbow Surgeons (ASES) scores at baseline, 1 year postoperatively, and final follow-up. Anatomic outcomes were evaluated by using postoperative magnetic resonance imaging at 1 year after surgery.

RESULTS

No significant differences in demographic characteristics and baseline data were observed between groups 1 and 2. Clinical symptoms were significantly improved at the final follow-up in both groups (P < .001). At the final follow-up, no significant differences were found in VAS pain (P = .676), SST (P = .598), UCLA (P = .100), Constant (P = .469), or ASES (P = .880) scores. However, the retear rate was lower in group 1 (4/21, 19.0%) than in group 2 (25/54, 46.3%) (P = .036), and the medial-row failure rate (type 2 retears) was much lower in group 1 (0/4, 0%) than in group 2 (18/25, 72.0%) (P = .014).

CONCLUSION

Concomitant bone marrow stimulation and patch augmentation significantly reduced retear and medial-row failure rates in the arthroscopic repair of massive rotator cuff tears.

Intra-articular injection, subacromial injection, and hydrodilatation for primary frozen shoulder: a randomized clinical trial

BACKGROUND

The aim of this prospective randomized study was to compare the efficacy of 3 injection methods, intra-articular injection, subacromial injection, and hydrodilatation (HD), in the treatment of primary frozen shoulder.

METHODS

Patients with primary frozen shoulder were randomized to undergo intra-articular injection (n = 29), subacromial injection (n = 29), or HD (n = 28). Evaluations using a visual analog scale for pain, Simple Shoulder Test, Constant score, and passive range of shoulder motion were completed before treatment and 1 month, 3 months, and 6 months after treatment.

RESULTS

Among the 3 injection methods for primary frozen shoulder, HD resulted in a greater range of motion in forward flexion and external rotation, a lower visual analog scale score for pain after 1 month, and better outcomes for all functional scores after 1 month and 3 months of follow-up. However, there were no significant differences in any clinical outcomes among the 3 groups in the final follow-up at 6 months.

CONCLUSIONS

Although HD yielded more rapid improvement, the 3 injection methods for primary frozen shoulder resulted in similar clinical improvement in the final follow-up at 6 months.

The Interrater and Intrarater Agreement of a Modified Neer Classification System and Associated Treatment Choice for Lateral Clavicle Fractures

BACKGROUND

As there is substantial variation in the classification and diagnosis of lateral clavicle fractures, proper management can be challenging. Although the Neer classification system modified by Craig has been widely used, no study has assessed its validity through inter- and intrarater agreement.

PURPOSE

To determine the inter- and intrarater agreement of the modified Neer classification system and associated treatment choice for lateral clavicle fractures and to assess whether 3-dimensional computed tomography (3D CT) improves the level of agreement.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

Nine experienced shoulder specialists and 9 orthopaedic fellows evaluated 52 patients with lateral clavicle fractures, completing fracture typing according to the modified Neer classification system and selecting a treatment choice for each case. Web-based assessment was performed using plain radiographs only, followed by the addition of 3D CT images 2 weeks later. This procedure was repeated 4 weeks later. Fleiss κ values were calculated to estimate the inter- and intrarater agreement.

RESULTS

Based on plain radiographs only, the inter- and intrarater agreement of the modified Neer classification system was regarded as fair (κ = 0.344) and moderate (κ = 0.496), respectively; the inter- and intrarater agreement of treatment choice was both regarded as moderate (κ = 0.465 and 0.555, respectively). Based on the plain radiographs and 3D CT images, the inter- and intrarater agreement of the classification system was regarded as fair (κ = 0.317) and moderate (κ = 0.508), respectively; the inter- and intrarater agreement of treatment choice was regarded as moderate (κ = 0.463) and substantial (κ = 0.623), respectively. There were no significant differences in the level of agreement between the plain radiographs only and plain radiographs plus 3D CT images for any κ values (all P > .05).

CONCLUSION

The level of interrater agreement of the modified Neer classification system for lateral clavicle fractures was fair. Additional 3D CT did not improve the overall level of interrater or intrarater agreement of the modified Neer classification system or associated treatment choice. To eliminate a common source of disagreement among surgeons, a new classification system to focus on unclassifiable fracture types is needed.

Prognostic Factors of Arthroscopic Extensor Carpi Radialis Brevis Release for Lateral Epicondylitis

PURPOSE

The purpose of this study was to analyze factors affecting the treatment outcomes and prognoses of arthroscopic debridement for refractory lateral epicondylitis.

METHODS

We included 45 patients who had undergone arthroscopic extensor carpi radialis brevis release for chronic refractory lateral epicondylitis between October 2008 and December 2012. Demographic data, magnetic resonance imaging studies, and arthroscopic findings were examined and analyzed.

RESULTS

The mean age of the enrolled patients (23 men and 22 women) was 45.9 ± 7.8 years, and the mean follow-up duration was 26.9 ± 9.0 months. All the patients showed significant clinical improvement on all parameters assessed using the visual analog scale (6.9 preoperatively to 0.9 postoperatively), the Upper Extremity Functional Scale (34.8 to 66.7), and the Mayo Elbow Score (63.5 to 92.3) (P < .05). There were no reports of serious surgical complications. At final follow-up, 37 patients (82.2%) were satisfied with their outcomes whereas 8 patients (17.8%) were dissatisfied. In terms of demographic factors, female sex was significantly different between the 2 groups. On preoperative magnetic resonance imaging, 7 patients in the satisfied group (18.9%) had a definite tendon lesion (grade III defect, ≥6 mm) whereas 6 patients in the dissatisfied group (75%) had a grade III defect (P = .016).

CONCLUSIONS

Overall, clinical outcome scores showed improvement after arthroscopic extensor carpi radialis brevis release for refractory lateral epicondylitis. However, preoperative tendon status and sex were associated with dissatisfaction and poor postoperative outcomes after the arthroscopic release procedure.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Arthroscopic repair of partial-thickness and small full-thickness rotator cuff tears: tendon quality as a prognostic factor for repair integrity

BACKGROUND

The healing failure rate is high for partial-thickness or small full-thickness rotator cuff tears.

PURPOSE

To retrospectively evaluate and compare outcomes after arthroscopic repair of high-grade partial-thickness and small full-thickness rotator cuff tears and factors affecting rotator cuff healing.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Included in the study were 55 consecutive patients (mean age, 57.9 ± 7.2 years) who underwent arthroscopic repair for high-grade partial-thickness (n = 34) and small full-thickness (n = 21) rotator cuff tears. The study patients also underwent magnetic resonance imaging (MRI) preoperatively and computed tomography arthrography (CTA) at least 6 months postoperatively, and their functional outcomes were evaluated preoperatively and at the last follow-up (>24 months). All partial-thickness tears were repaired after being converted to full-thickness tears; thus, the repair process was almost the same as for small full-thickness tears. The tendinosis of the torn tendon was graded from the MRI images using a 4-point scale, and the reliabilities were assessed. The outcomes between high-grade partial-thickness tears that were converted to small full-thickness tears and initially small full-thickness tears were compared, and factors affecting outcomes were evaluated.

RESULTS

The inter- and intraobserver reliabilities of the tendinosis grade were good (intraclass correlation coefficient, 0.706 and 0.777, respectively). Failure to heal as determined by CTA was observed in 12 patients with a high-grade partial-thickness tear (35.3%; complete failure in 4 and partial failure in 8) and in 3 patients with a small full-thickness tear (14.3%; complete failure in 1 and partial failure in 2). The patients with high-grade partial-thickness rotator cuff tears showed a higher tendinosis grade than did those with small full-thickness tears (P = .014), and the severity of the tendinosis was related to the failure to heal (P = .037). Tears with a higher tendinosis grade showed a 7.64-times higher failure rate (95% CI, 1.43-36.04) than did those with a lower tendinosis grade (P = .013). All functional outcome scores improved after surgery (all P < .001); however, there was no difference between groups.

CONCLUSION

The high-grade partial-thickness rotator cuff tears showed more severe tendinosis compared with the small full-thickness tears in this study. Contrary to previous impressions that tear size or fatty infiltration is the factor that most influences healing, tendinosis severity assessed by preoperative MRI was the only factor associated with failure to heal, given the numbers available for analysis, in patients with partial-thickness and small full-thickness rotator cuff tears. Surgeons should pay more attention to tendon quality during repair surgery or rehabilitation in smaller rotator cuff tears, especially in high-grade partial-thickness tears with severe tendinosis.

Comparison of results between hook plate fixation and ligament reconstruction for acute unstable acromioclavicular joint dislocation

Background

In the present study, we aimed to compare clinical and radiographic outcomes between hook plate fixation and coracoclavicular (CC) ligament reconstruction for the treatment of acute unstable acromioclavicular (AC) joint dislocation.

Methods

Forty-two patients who underwent surgery for an unstable acute dislocation of the AC joint were included. We divided them into two groups according to the treatment modality: internal fixation with a hook plate (group I, 24 cases) or CC ligament reconstruction (group II, 18 cases). We evaluated the clinical outcomes using a visual analog scale (VAS) for pain and Constant-Murley score, and assessed the radiographic outcomes based on the reduction and loss of CC distance on preoperative, postoperative, and final follow-up plain radiographs.

Results

The mean VAS scores at the final follow-up were 1.6 ± 1.5 and 1.3 ± 1.3 in groups I and II, respectively, which were not significantly different. The mean Constant-Murley scores were 90.2 ± 9.9 and 89.2 ± 3.5 in groups I and II, respectively, which were also not significantly different. The AC joints were well reduced in both groups, whereas CC distance improved from a mean of 215.7% ± 50.9% preoperatively to 106.1% ± 10.2% at the final follow-up in group I, and from 239.9% ± 59.2% preoperatively to 133.6% ± 36.7% at the final follow-up in group II. The improvement in group I was significantly superior to that in group II (p < 0.001). Furthermore, subluxation was not observed in any case in group I, but was noted in six cases (33%) in group II. Erosions of the acromion undersurface were observed in 9 cases in group I.

Conclusions

In cases of acute unstable AC joint dislocation, hook plate fixation and CC ligament reconstruction yield comparable satisfactory clinical outcomes. However, radiographic outcomes based on the maintenance of reduction indicate that hook plate fixation is a better treatment option.

Diagnostic value of four clinical tests for the evaluation of subscapularis integrity

HYPOTHESIS

The lift-off, internal rotation lag sign, belly-press, and bear-hug tests are widely used to evaluate the integrity of the subscapularis. We hypothesized that these tests might reflect different types of subscapularis tears and sought to ascertain whether these tests accurately determine the severity of the internal rotation strength deficit and fatty degeneration.

METHODS

Isokinetic testing and the 4 clinical tests were used preoperatively to evaluate 312 patients who had undergone arthroscopic rotator cuff surgery. Of these, 37 patients had a full-thickness subscapularis tear, 96 had a partial-thickness tear, and 179 had no tear.

RESULTS

For differentiating any tears from an intact subscapularis, the most sensitive test was the belly-press test (27.8%), and the most specific test was the lift-off test (100%). For differentiating a full-thickness tear from a partial tear, the most sensitive test was the belly-press test (56.8%), and the most specific was the lift-off test (96.9%). A positive lift-off test also most reflected loss of internal rotation strength (mean, 72.2%; 95% confidence interval, 61.9-82.5), followed by the internal rotation lag sign (55.1%; 44.2-66.1) and the belly-press test (45.9%; 36.4-54.4).

CONCLUSIONS

A positive lift-off test was highly specific for the detection of a full-thickness subscapularis tear and to reflect severe fatty degeneration. The lift-off, internal rotation lag sign, belly-press, and bear-hug tests sequentially predict internal rotation strength deficit and provide discrimination of internal rotation strength impairment.

Subdeltoid lipoma arborescens combined with rotator cuff tears

Lipoma arborescens, a rare benign intra-articular lesion, is characterized by lipomatous proliferation of the synovium in which the subsynovial tissue is replaced by mature adipocytes. Subdeltoid bursa is a rare location for lipoma arborescens, and only a few cases have been reported in the literature. This article reports 2 cases of subdeltoid lipoma arborescens combined with rotator cuff tears, and the possible relationships between subdeltoid lipoma arborescens and rotator cuff tears are discussed. The intra-articular villous proliferations on fat-suppressed T2-weighted magnetic resonance imaging appeared as yellowish-white lipomatous villous proliferations on arthroscopy, and finger-like lipomatous proliferation of the synovium, where the subsynovial connective tissue is replaced by mature adipocytes, on histology. Although further evidence would be necessary, the bony proliferations, in addition to bone-to-bone abrasion and inflammatory processes, may contribute to the relationship between subdeltoid lipoma arborescens and rotator cuff tears. Because this is a rare disease in a rare location, no established treatment guidelines are available for lipoma arborescens in subdeltoid bursa. For the current patients, arthroscopic excision of the lipoma arborescens and concomitant rotator cuff repair were prescribed after more than 6 months of conservative management. All patients had symptom relief and were satisfied with their results. Paying special attention to the radiologic and arthroscopic characteristics of the lipoma arborescens will help physicians and surgeons to achieve a more accurate diagnosis and effective treatment strategy, especially in patients with concomitant rotator cuff tears.

Is the supraspinatus muscle atrophy truly irreversible after surgical repair of rotator cuff tears?

BACKGROUND

Atrophy of rotator cuff muscles has been considered an irreversible phenomenon. The purpose of this study is to evaluate whether atrophy is truly irreversible after rotator cuff repair.

METHODS

We measured supraspinatus muscle atrophy of 191 patients with full-thickness rotator cuff tears on preoperative magnetic resonance imaging and postoperative multidetector computed tomography images, taken at least 1 year after operation. The occupation ratio was calculated using Photoshop CS3 software. We compared the change between pre- and postoperative occupation ratios after modifying the preoperative occupation ratio. In addition, possible relationship between various clinical factors and the change of atrophy, and between the change of atrophy and cuff integrity after surgical repair were evaluated.

RESULTS

The mean occupation ratio was significantly increased postoperatively from 0.44 ± 0.17 to 0.52 ± 0.17 (p < 0.001). Among 191 patients, 81 (42.4%) showed improvement of atrophy (more than a 10% increase in occupation ratio) and 33 (17.3%) worsening (more than a 10% decrease). Various clinical factors such as age tear size, or initial degree of atrophy did not affect the change of atrophy. However, the change of atrophy was related to repair integrity: cuff healing failure rate of 48.5% (16 of 33) in worsened atrophy; and 22.2% (18 of 81) in improved atrophy (p = 0.007).

CONCLUSIONS

The supraspinatus muscle atrophy as measured by occupation ratio could be improved postoperatively in case of successful cuff repair.

Prediction of chronicity of anterior cruciate ligament tear using MRI findings

Background

The estimation of anterior cruciate ligament (ACL) tear is required in certain cases involving legal and financial administration, such as the worker's compensation and/or insurance. The aim of this study is to propose and evaluate a quantitative evaluation instrument to estimate the chronicity of the ACL tear, based on the four magnetic resonance imaging (MRI) findings.

Methods

One hundred and fifty one cases of complete ACL tear confirmed by arthroscopy were divided into 4 groups according to the time from ACL injury to MRI acquisition: acute (< 6 weeks), subacute (6 weeks to 3 months), intermediate (3 months to 1 year), and chronic (> 1 year). The four MRI findings including ACL morphology, joint effusion, posterior cruciate ligament angle, and bone bruise were analyzed for temporal changes among the 4 groups. Binary logistic regression equations were formulated using the MRI findings to estimate the chronicity of ACL tear in a quantitative manner, and the accuracy of the formulated regression equations was evaluated.

Results

The four MRI findings showed substantial temporal correlation with the time-limits of ACL injury to be included in the estimation model. Three predictive binary logistic equations estimated the probability of the ACL injury for the three cutoff time-limits of 6 weeks, 3 months, and 1 year with accuracies of 82.1%, 89.4%, and 89.4%, respectively.

Conclusions

A series of predictive logistic equations were formulated to estimate the chronicity of ACL tear using 4 MRI findings with chronological significance.

What do the patients want and worry in Korean patients who undergo arthroscopic rotator cuff surgery?

Background

To specify what patients want and worry preoperatively is important in orthopedic practice. The aim of the current study was to analyze the patient characteristics of rotator cuff disease in Korean population who were willing to undergo arthroscopic surgery, and to evaluate the differences in expectations and concerns by age and gender.

Methods

We prospectively enrolled 303 patients who underwent rotator cuff surgery between April 2004 and August 2008. Three questionnaires were completed before surgery: the first one addressing preoperative patient's expectation, the second one focusing on concerns by covering 64 items using a visual analogue scale, and the third one evaluating patient's demographic characteristics. The characteristics of preoperative expectation, concern, and demographic data were evaluated according to gender and age group.

Results

Female patients had lower level of sports activity (p = 0.007) and lower levels of information (p = 0.028). Gender specific worries are about a caregiver during hospital stay, operating on the working side, fear about ugly scars, postoperative pain, applying makeup or combing hair. The older group responded that they can't be willing to change activities of daily living (p = 0.001), are not living with a spouse (p = 0.002), had previous shoulder operation history (p = 0.008), and had a lower level of information (p = 0.007). They especially worried about medical bills, worried about the physician being too young and inexperienced, postoperative pain, loss of arm function, and hospital food.

Conclusions

Our data showed what Korean patients wanted and were concerned about prior to rotator cuff surgery. This can empower patients to formulate realistic expectations and make informed decisions. We feel that we can achieve higher levels of postoperative satisfaction by analyzing expectations and concerns in depth and addressing these proactively.