Chronic Rotator Cuff Research Articles

The Effect of Tendon Delamination on Rotator Cuff Healing

Background: While patient age, tear size, and muscle fatty infiltration are factors known to affect the rate of tendon healing after rotator cuff repair, the effect of tendon delamination is less known. Purpose: To assess the effect of tendon delamination on rotator cuff healing after arthroscopic single-row (SR) repair. Study Design: Cohort study; Level of evidence, 3. Methods: Consecutive patients (N = 117) with chronic full-thickness rotator cuff tears underwent arthroscopic SR repair with the tension-band cuff repair. The mean ± SD age at the time of surgery was 60 ± 8 years. There were 25 small, 63 medium, and 29 large tears. Tendon delamination was assessed intraoperatively under arthroscopy with the arthroscope placed in the lateral portal. Patients were divided into 2 groups: those with nondelaminated (n = 80) and delaminated (n = 37) cuff tears. The 2 groups were comparable for age, sex, body mass index, preoperative pain, strength, and a Constant-Murley score. Repair integrity was evaluated with sonography (mean, 24 months after surgery; range, 6-62 months) and classified into 3 categories: type A, indicating complete, homogeneous, and thick coverage of the footprint; type B, partial coverage with a thin tendon; and type C, no coverage of the footprint. Results: The prevalence of tendon delamination observed under arthroscopy was 32% (37 of 117), which increased with tear size and retraction: from 15% in small tears to 32% in medium tears and 45% in large tears (P = .028). Postoperatively, 83 patients had complete coverage of footprint (type A = 71%) and the cuff was considered healed, whereas 26 had partial coverage or a thin tendon (type B = 22%) and 8 had no coverage (type C = 7%). Overall, the rate of complete healing was 78% in nondelaminated cuff tears and 57% in the case of tendon delamination (P = .029). In large retracted tears, the healing rate dropped from 81% in the absence of delamination to 39% when the tendons were delaminated (P = .027). Conclusion: Tendon delamination increases with tear size and retraction. Patients with chronic delaminated and retracted rotator cuff tears (stage 2 or 3) are at risk of failure after SR cuff repair, whereas patients with small delaminated rotator cuff tears (stage 1) involving only the supraspinatus can be treated with an SR cuff repair with a high chance of tendon healing. These results suggest that SR cuff repair may be insufficient to treat delaminated chronic cuff tears. To improve the anatomic outcomes of rotator cuff repairs, surgeons should consider treating delaminated tears with a double-row or double-layer repair.

Efficacy of Imaging Modalities Assessing Fatty Infiltration in Rotator Cuff Tears.

Fatty atrophy is a diagnosis characterized by the combination of fatty infiltration and muscle atrophy of the rotator cuff. Studies have shown a strong positive correlation between the level of fatty infiltration and the risk of experiencing a chronic rotator cuff tear. Therefore, the purpose of the present study was to review the current literature on radiographic imaging of fatty infiltration and fatty atrophy to better aid surgeons in predicting functional outcome and to help guide patient decisions. We conducted a literature search in PubMed. The exact search queries included "rotator cuff" in the MeSH Terms field; "fatty atrophy," fatty infiltration," and "fatty muscle degeneration" in the Title/Abstract field; and various combinations of these searches. We initially found 184 articles using these keywords, including both human and animal studies. The 25 animal studies were excluded, leaving 159 articles. The abstracts of all remaining articles were reviewed and selected on the basis of our inclusion criteria of focusing on patients with rotator cuff tears (preoperatively and postoperatively), fatty infiltration, fatty atrophy, and imaging modalities. We excluded an additional 127 articles, leaving 32 articles that were selected for the final review and inclusion in this study. Among 45 shoulder specialists across different studies, interrater agreement for Goutallier staging with use of magnetic resonance imaging (MRI) ranged from 0.24 to 0.82 and intrarater agreement for supraspinatus fatty changes ranged from 0.34 to 0.89. Our review also showed strong positive correlations when assessing the severity of fatty atrophy of the rotator cuff between MRI and ultrasound or ultrasound modalities such as sonoelastography. Increasing fatty infiltration of the rotator cuff is associated with greater repair failure rates and hence poorer overall clinical outcomes. MRI remains the gold standard for the imaging of rotator cuff tears and postoperative healing. Ultrasound can decrease health-care expenditures associated with the assessment of repair integrity postoperatively, although ultrasound is not as precise and has some limitations compared with MRI.

Shoulder Infrared Thermography in Chronic Rotator Cuff Tears - Temperature Assessment and Variation in Affected and Non-Affected Shoulders

Shoulder Infrared Thermography in Chronic Rotator Cuff Tears - Temperature Assessment and Variation in Affected and Non-Affected Shoulders

Predictors of allocation to surgery in patients older than 50 years with partial-thickness rotator cuff tear

The purpose of this study was to determine the predictive factors for allocation to surgery in patients older than 50 years with symptomatic chronic partial-thickness rotator cuff tear (PTRCT). Patients older than 50 years with a confirmed diagnosis of unilateral isolated PTRCT were included in this retrospective study. In the minimum follow-up of 2 years, eventual allocation to surgical or nonsurgical treatment was determined individually. Patients who underwent surgery were defined as failed conservative management and allocation to surgery. Data pertaining to patients' demographics, functional comorbidity index values, duration of symptoms, and American Shoulder and Elbow Surgeons scores were collected from our medical records. Tear side and Ellman classification, subacromial spur, and acromiohumeral intervals were also noted. A regression analysis was performed to determine the major predictors of allocation to surgery. There were 202 patients with a mean age of 62 years in group I (no-surgery group) and 70 patients with a mean age of 57 years in group II (surgery group). The mean age and functional comorbidity index values were significantly higher in group I than in group II (P < .001 and P < .001, respectively). Bursal-sided tears were significantly more common in group II (P = .026). According to the findings of regression analysis, tear side and functional comorbidity index were the major predictors of allocation to surgery (P = .015 and P < .001, respectively). Our study results indicate that in patients older than 50 years with PTRCTs, those with fewer comorbidities and bursal-sided PTRCTs were significantly more likely to undergo surgery.

Human Tendon–Derived Collagen Hydrogel Significantly Improves Biomechanical Properties of the Tendon-Bone Interface in a Chronic Rotator Cuff Injury Model

Poor healing of the tendon-bone interface (TBI) after rotator cuff (RTC) tears leads to high rates of recurrent tear following repair. Previously, we demonstrated that an injectable, thermoresponsive, type I collagen-rich, decellularized human tendon-derived hydrogel (tHG) improved healing in an acute rat Achilles tendon injury model. The purpose of this study was to investigate whether tHG enhances the biomechanical properties of the regenerated TBI in a rat model of chronic RTC injury and repair. Tendon hydrogel was prepared from chemically decellularized human cadaveric flexor tendons. Eight weeks after bilateral resection of supraspinatus tendons, repair of both shoulders was performed. One shoulder was treated with a transosseous suture (control group) and the other was treated with a transosseous suture plus tHG injection at the repair site (tHG group). Eight weeks after repair, the TBIs were evaluated biomechanically, histologically, and via micro-computed tomography (CT). Biomechanical testing revealed a larger load to failure, higher stiffness, higher energy to failure, larger strain at failure, and higher toughness in the tHG group versus control. The area of new cartilage formation was significantly larger in the tHG group. Micro-CT revealed no significant difference between groups in bone morphometry at the supraspinatus tendon insertion, although the tHG group was superior to the control. Injection of tHG at the RTC repair site enhanced biomechanical properties and increased fibrocartilage formation at the TBI in a chronic injury model. Treatment of chronic RTC injuries with tHG at the time of surgical treatment may improve outcomes after surgical repair.

Advance of massive tear of the rotator cuff treated with a deltoid flap

Massive rotator cuff tears often destroy equilibrium of couples of the shoulder joints, whichlead toshoulder pain and functional incapacitation. At present, there is a great controversy about the best treatment strategy for the massive rotator cuff tear, nevertheless surgery has been proved to have more satisfactory results than non-operative treatment. It has been confirmed by numerous studies that cuff repair could prevent loss of shoulder strength and glenohumeral osteoarthritis. However, it is impossible to suture tendon to bone directly due to retraction of tendon stump, fat infiltration of rotator cuff and prominent tear size in massive rotator cuff tear. Muscular flap transfer procedures have played important roles in the treatment of massive rotator cuff tears. Compared with other tendon transposition procedures, such as latissimus dorsi transfer, the deltoid muscular flap may be an optimal method as it works synergistically with the infraspinatus and supraspinatus muscle, and presses down the humeral head potentially. Cuff repair in open operation with tendon stump re-attachment to the deltoid muscle flap, aims to reconstruct the cuff continuity and cover the humeral head toform a new cuff. The deltoid muscle flap, also acting as a muscle cushion, is expected to reduce impingement between the humeral head and the acromion and get better results of pain relief and improvement of shoulder function. However, it is still controversial about the efficacy of deltoid muscle flap transfer in reconstructing a new balance of couple with better shoulder strength, alleviating glenohumeral arthritis and preventing tendon retears. This article reviews the advances in the treatment of chronic massive rotator cuff tears with deltoid flap transfer.

Validation of a tool to assess patient satisfaction, waiting times, healthcare utilization, and cost.

Patients' experience of the quality of care received throughout their continuum of care can be used to direct quality improvement efforts in areas where they are most needed. This study aims to establish validity and reliability of the Healthcare Access and Patient Satisfaction Questionnaire (HAPSQ) - a tool that collects patients' experience that quantifies aspect of care used to make judgments about quality from the perspective of the Alberta Quality Matrix for Health (AQMH). The AQMH is a framework that can be used to assess and compare the quality of care in different healthcare settings. The AQMH provides a common language, understanding, and approach to assessing quality. The HAPSQ is one tool that is able to assess quality of care according to five of six AQMH's dimensions. This was a prospective methodologic study. Between March and October 2015, a convenience sample of patients presenting with chronic full-thickness rotator cuff tears was recruited prospectively from the University of Calgary Sport Medicine Centre in Calgary, Alberta, Canada. Reliability of the HAPSQ was assessed using test-retest reliability [interclass correlation coefficient (ICC)>0.70]. Validity was assessed through content validity (patient interviews, floor and ceiling effects), criterion validity (percent agreement >70%), and construct validity (hypothesis testing). Reliability testing was completed on 70 patients; validity testing occurred on 96 patients. The mean duration of symptoms was three years (SD: 5.0, range: 0.1-29). Only out-of-pocket utilization possessed an ICC<0.70. Patients reported that items were relevant and appropriate to measuring quality of care. No floor or ceiling effects were present. Criterion validity was reached for all items assessed. A priori hypotheses were confirmed. The HAPSQ represents an inexpensive, reliable, and valid approach toward collecting clinical information across a patient's continuum of care.

Effects of hypertonic dextrose injection in chronic supraspinatus tendinopathy of the shoulder: a randomized placebo-controlled trial.

Rotator cuff lesions are common causes of shoulder pain. Although patients with symptoms caused by chronic rotator cuff tendinopathy can be treated using conservative treatments, some of them may still experience refractory symptoms. Hypertonic dextrose prolotherapy (DPT) may be another treatment choice for these refractory symptoms. The aim of this study was to evaluate the effects of an ultrasound-guided hypertonic dextrose injection for patients with chronic supraspinatus tendinopathy. Randomized double-blind placebo-controlled trial. Academic medical center. Outpatients patients (N.=31) with chronic supraspinatus tendinopathy and shoulder pain for more than six months. Study group treated with one dose of an ultrasound-guided hypertonic dextrose (20%) injection at the supraspinatus enthesis site, whereas control patients received one dose of 5% normal saline through the same method. The Visual Analog Scale (VAS), Shoulder Pain And Disability Index (SPADI), shoulder active range of motion (AROM) and ultrasonographic thickness and histogram results of the supraspinatus tendon were evaluated before intervention and at two and six weeks after intervention. The outcome differences between the study and control groups were analyzed by using repeated-measures analysis of variance (ANOVA). In total, 31 patients completed the study. The study group indicated a significant improvement in the VAS (P=0.001), SPADI scores (P=0.017), shoulder AROM of flexion (P=0.039), and abduction (P=0.043) compared with the control group at two weeks after the injection. However, the effect did not sustain until six weeks after the injection. No differences in the histograms and morphological changes (thickness) were noted before and after injection in both groups. This study revealed that the ultrasound-guided hypertonic dextrose injection relieved pain, disability, and improved shoulder AROM for a short period in patients with chronic supraspinatus tendinopathy. For patients with chronic shoulder pain and supraspinatus tendinopathy, ultrasound-guided hypertonic dextrose injections can provide relief from pain, disability, and shoulder range of motion for up to two weeks after intervention.

The effectiveness and safety of thread-embedding acupuncture for chronic rotator cuff disease: A study protocol for a randomized, patient-assessor-blinded, controlled, clinical trial

IntroductionThis report provides a clinical study protocol designed to verify the effects and safety of thread-embedding acupuncture (TEA) for chronic rotator cuff disease with regard to pain relief, improvement of shoulder function, and quality of life. Methods/designThis is a study protocol of a randomized patient-assessor-blinded, controlled, clinical trial. This study will be carried out at Kyung Hee University Hospital at Gangdong in Korea. Participants with shoulder pain lasting more than 3 months will be recruited to the study. After eligibility screening, a total of 64 participants will be randomly allocated to one of the 2 groups in this trial, with 32 participants in each group. Over the 8 weeks treatment period, TEA and sham TEA will be performed in the respective groups once a week. In the follow-up phase, participants will undergo a telephone interview after 12 weeks and will visit for a final evaluation after 16 weeks. ResultsThe primary outcome measure is the change in pain intensity between baseline and treatment completion (8 weeks). Secondary outcome measures include the values for pain intensity, shoulder disability, safety, satisfaction, and quality of life. ConclusionsPrevious studies have shown that TEA could be an alternative treatment for shoulder pain. However, there is still a lack of scientific evidence regarding the effectiveness of TEA for chronic rotator cuff disease. This study will provide useful evidence regarding the effectiveness and safety of TEA treatment. The findings will serve as important data for conducting additional acupuncture studies on chronic rotator cuff disease.

The effect of adipose-derived stem cells on enthesis healing after repair of acute and chronic massive rotator cuff tears in rats

Chronic massive rotator cuff tears heal poorly and often retear. This study investigated the effect of adipose-derived stem cells (ADSCs) and transforming growth factor-β3 (TGF-β3) delivered in 1 of 2 hydrogels (fibrin or gelatin methacrylate [GelMA]) on enthesis healing after repair of acute or chronic massive rotator cuff tears in rats. Adult male Lewis rats underwent bilateral transection of the supraspinatus and infraspinatus tendons with intramuscular injection of botulinum toxin A (n = 48 rats). After 8 weeks, animals received 1 of 8 interventions (n = 12 shoulders/group): (1) no repair, (2) repair only, or repair augmented with (3) fibrin, (4) GelMA, (5) fibrin + ADSCs, (6) GelMA + ADSCs, (7) fibrin + ADSCs + TGF-β3, or (8) GelMA + ADSCs + TGF-β3. An equal number of animals underwent acute tendon transection and immediate application of 1 of 8 interventions. Enthesis healing was evaluated 4 weeks after the repair by microcomputed tomography, histology, and mechanical testing. Increased bone loss and reduced structural properties were seen in chronic compared with acute tears. Bone mineral density of the proximal humerus was higher in repairs of chronic tears augmented with fibrin + ADSCs and GelMA + ADSCs than in unrepaired chronic tears. Similar improvement was not seen in acute tears. No intervention enhanced histologic appearance or structural properties in acute or chronic tears. Surgical repair augmented with ADSCs may provide more benefit in chronic tears compared with acute tears, although there was no added benefit to supplementing ADSCs with TGF-β3.

Kronik rotator manşet yırtığı olan hastaların tedavisinde basit çift-sıra rotator manşet tamiri ile "Belt and Suspender’s" tekniğinin karşılaştırılması

Aim: Surgical treatment of chronic rotator cuff tears is still unclear. Many surgical techniques have been used in the treatment. The aim of the study is to compare the functional outcomes of two different surgical techniques.Methods: Of the 27 patients in the study; 13 underwent Belt and Suspender's Technique (2 male, 11 female), 14 underwent simple double row rotator cuff repair technique (4 male, 10 female). Clinical assessment was made according to American Shoulder and Elbow Surgeons (ASES) scoring system and Visual Analog Scale (VAS).Results: There was no statistically significant difference between postoperative ASES scores, VAS scores, range of motions (ROM) and complications. In both groups, failure of healing was seen in one each patient. Conclusion: According to this study treatment for chronic rotator cuff tear using a Belt and Suspender's technique is as effective and reliable as simple double row cuff repair technique method with low complication rates and good results can be achieved in clinical outcomes in the early postoperative period.

Comparison of two different superior capsule reconstruction methods in the treatment of chronic irreparable rotator cuff tears: a biomechanical and histologic study in rabbit models

In the treatment of irreparable rotary cuff (RC) tears, the superior capsule of the shoulder is reconstructed using tensor fascia lata (TFL) or several allografts to prevent progressive joint degeneration. This study compared the healing qualities of acellular human dermal graft (HDG) and the TFL autograft in superior capsule reconstruction (SCR) from biomechanical and histologic perspectives. Chronic retracted RC tear models were created bilaterally in 9 rabbits, and 7 rabbits with intact RC were used as a control group. SCR was performed 8 weeks after the tear using HDG in right shoulders and TFL in left shoulders. At 12 weeks after SCR, 2 shoulders from each experimental group were investigated for histologic healing, and 7 samples from the experimental and control groups were biomechanically tested. Complete healing was observed macroscopically in the glenoid and humeral sides of both groups. No difference was observed in the enthesis maturation scores between the experimental groups. Collagen fiber density was higher and the orientation was better in TFL group. Inflammatory cell infiltration was not seen in the TFL group, but inflammatory cell infiltration was pronounced in the HDG group. The mean pullout strengths of the TFL group, HDG group, and intact RC group were 139.7 ± 40.5 N, 123.9 ± 47.9 N, and 105.1 ± 11.8 N (P = .187), respectively. The mean stiffness values (P = .711), yield forces (P = .404), and displacements (P = .135) were also statistically not different between the groups. In SCR, the healing qualities of HDG and TFL were similar in rabbit models.

Biceps Detachment Preserves Joint Function in a Chronic Massive Rotator Cuff Tear Rat Model

Background: Lesions of the long head of the biceps tendon are often associated with massive rotator cuff tears (MRCTs), and biceps tenotomy is frequently performed for pain relief and functional reservation. However, the efficacy and safety of biceps tenotomy regarding the effects on the surrounding tissues in chronic MRCT are unclear. Hypothesis: Biceps tenotomy would result in improved mechanical and histological properties of the intact subscapularis tendon and improved in vivo shoulder function while not compromising glenoid cartilage properties. Study Design: Controlled laboratory study. Methods: Right supraspinatus and infraspinatus tendons were detached in 25 male Sprague-Dawley rats, followed by 4 weeks of cage activity to create a chronic MRCT condition. Animals were randomly divided into 2 groups and received either biceps tenotomy (n = 11) or sham surgery (n = 14) and were sacrificed 4 weeks thereafter. Forelimb gait and ground-reaction forces were recorded 1 day before the tendon detachment (baseline), 1 day before the surgical intervention (biceps tenotomy or sham), and 3, 7, 10, 14, 21, and 28 days after the intervention to assess in vivo shoulder joint function. The subscapularis tendon and glenoid cartilage were randomly allocated for mechanical testing or histologic assessment after the sacrifice. Results: Compared with sham surgery, biceps tenotomy partially restored the in vivo shoulder joint function, with several gait and ground-reaction force parameters returning closer to preinjury baseline values at 4 weeks. With biceps tenotomy, mechanical properties of the subscapularis tendons were improved, while mechanical properties and histological Mankin scores of the glenoid cartilage were not diminished when compared with the sham group. Conclusion: Biceps tenotomy in the presence of chronic MRCT partially preserves overall shoulder function and potentially restores subscapularis tendon health without causing detrimental effects to joint cartilage. This laboratory study adds to the growing literature regarding the protective effects of biceps tenotomy on the shoulder joint in a chronic MRCT model. Clinical Relevance: This study provides important basic science evidence supporting the use of biceps tenotomy in patients with massive rotator cuff tears.

Immediate effects of kinesiotaping on acromiohumeral distance and shoulder proprioception in individuals with symptomatic rotator cuff tendinopathy

BackgroundKinesiotaping is widely used for the rehabilitation of rotator cuff tendinopathy. It has been argued to reduce symptoms and functional limitations through improvement of proprioceptive feedback. In addition, kinesiotaping has been reported to increase the subacromial space in healthy subjects. However, its effects on the acromiohumeral distance and shoulder proprioception of individuals with rotator cuff tendinopathy have not been ascertained. This study investigated the immediate effects of kinesiotaping on the acromiohumeral distance and shoulder proprioception in individuals with rotator cuff tendinopathy. MethodsTwenty-two individuals with chronic rotator cuff tendinopathy were included. The acromiohumeral distance was measured using an ultrasound scanner at rest and 60° shoulder abduction. Proprioception was measured through active joint repositioning in low- (45°–65°) and mid-amplitude (80°–100°) of shoulder flexion and abduction. A wireless inertial measurement unit system was used to quantify shoulder angles. First, measurements were taken without kinesiotaping. Thereafter, kinesiotaping was applied on the symptomatic shoulder, and the same measurements were retaken. Repeated measures ANOVAs were used for statistical analyses. FindingsKinesiotaping induced a significant increase in acromiohumeral distance at 60° abduction (∆AHD = 0.94 mm; 95%CI: 0.50–1.38, p < 0.001), exceeding the minimal detectable change (0.70 mm). No significant difference was observed in acromiohumeral distance at rest or in proprioception during active joint repositioning in both low- and mid-amplitude (p > 0.05). InterpretationKinesiotaping led to an immediate increase in acromiohumeral distance at 60° of abduction that, although it seems a minor change (↑10.5%), it may be significant for symptomatic patients, whereas it had no immediate effect on active joint repositioning.

Inhibition of calpain delays early muscle atrophy after rotator cuff tendon release in sheep.

Chronic rotator cuff (RC) tears are characterized by retraction, fat accumulation, and atrophy of the affected muscle. These features pose an intractable problem for surgical repair and subsequent recovery, and their prevention may be easier than reversal. Using an established ovine model, we tested the hypothesis that inhibition of the protease calpain mitigates m. infraspinatus atrophy by preservation of the myofibers’ structural anchors in the sarcolemma (the costameres). Already 2 weeks of distal tendon release led to a reduction in muscle volume (−11.6 ± 9.1 cm3, P = 0.038) and a 8.3% slow‐to‐fast shift of the fiber area (P = 0.046), which were both entirely abolished by chronic local administration of the calpain inhibitor calpeptin alone, and in combination with sildenafil. Calpain inhibition blunted the retraction of the muscle‐tendon unit by 0.8–1.0 cm (P = 0.020) compared with the control group, and prevented cleavage of the costameric protein talin. Calpain 1 and 2 protein levels increased in the medicated groups after 4 weeks, counteracting the efficacy of calpeptin. Hence atrophic changes emerged after 4 weeks despite ongoing treatment. These findings suggest that the early muscular adaptations in the specific case of RC tear in the ovine model are indistinguishable from the atrophy and slow‐to‐fast fiber transformation observed with conventional unloading and can be prevented for 2 weeks. Concluding, calpain is a potential target to extend the temporal window for reconstruction of the ruptured RC tendon before recovery turns impossible.

Therapeutic Effects of Umbilical Cord Blood-Derived Mesenchymal Stem Cells Combined with Polydeoxyribonucleotides on Full-Thickness Rotator Cuff Tendon Tear in a Rabbit Model

While therapies using mesenchymal stem cells (MSCs) to treat rotator cuff tendon tear (RCTT) have yielded some promising preliminary results, MSCs therapy has not yet completely regenerated full-thickness RCTT (FTRCTT). It has recently been reported that polydeoxyribonucleotide (PDRN) is effective in the treatment of chronic rotator cuff disease. We hypothesized that local injection of human umbilical cord blood-derived (UCB)–MSCs with PDRN would be more effective in regenerating tendon tear than UCB-MSCs alone. The purpose of this study was to evaluate the effects of UCB–MSCs combined with different doses of PDRN on the regeneration of RCTT in a chronic RCTT model by using a rabbit model. New Zealand white rabbits (n = 24) with FTRCTT were allocated randomly into three groups (8 rabbits per group). Three different injectants (G1-S, 0.2 mL UCB-MSCs; G2-P1, 0.2 mL UCB-MSCs with one injection of 0.2 mL PDRN; G3-P4, 0.2 mL UCB-MSCs, and four injections of 0.2 mL PDRN per week) were injected into FTRCTT under US-guidance. After the rabbits were euthanized, we evaluated ross morphological and histological change. Motion analysis was also performed. There were significant differences in gross morphological changes between before, and at 4 weeks after injection, in all three groups, but no differences were found among the three groups. Masson’s trichrome (MT) or anti-type 1 collagen antibody (COL-1)-positive cell densities in G2-P1 and G3-P4 were improved significantly compared with those in G1-S, but showed no significant difference between G2-P1 and G3-P4. On motion analysis, walking distance and fast walking time in G2-P1 and G3-P4 were significantly longer/higher than those in G1-S, but showed no significant differences between G2-P1 and G3-P4. These results demonstrated that there was no significant difference in the gross morphologic change of tendon tear between UCB-MSCs only and combination with PDRN injection in rabbit model of chronic traumatic FTRCTT. Furthermore, there were no significant differences in the regenerative effects between high and low doses of (0.8 and 0.2) mL of PDRN.

Arthroscopic Superior Capsular Reconstruction or Reverse Total Shoulder Arthroplasty for Irreparable Bilateral Rotator Cuff Tear

An active elderly patient with bilateral chronic rotator cuff tear underwent a reverse total shoulder arthroplasty (RTSA) on the right shoulder and an arthroscopic superior capsular reconstruction (ASCR) with a fascia lata autograft on the left shoulder. To our knowledge, this is the first reported case that compares these 2 techniques for irreparable rotator cuff tears in the same patient. The patient had very good midterm (2 and 8 years of follow-up) functional outcomes with both treatment options. However, the ASCR was found to have superior clinical outcome measures, and it is a valid alternative to RTSA for irreparable rotator cuff tears in the appropriate setting.

Increasing the deltoid muscle volume positively affects functional outcomes after arthroscopic rotator cuff repair.

The aim of this study was to determine the effect of changes in deltoid muscle volume (DMV) on the clinical outcomes of patients who underwent arthroscopic repair due to chronic rotator cuff rupture. A total of 54 patients (35 females, 19 males) between 40 and 70years of age who underwent single-row arthroscopic repair due to chronic rotator cuff tears were compared via preoperative (preop) and postoperative (postop) (6-12months) magnetic resonance imaging (MRI) to determine the total DMV (tDMV). A clinical evaluation was performed with American Shoulder and Elbow Surgeons (ASES) and Constant scores in both the preop and postop groups. tDMV values were also measured in a randomly selected control group (50 patients). A standardized rehabilitation program was recommended for all patients. Positive correlations were found between the change in tDMV (ΔtDMV) and ASES and Constant scores (p < 0.03 and p < 0.032, respectively). The preop tDMV value was significantly lower in the patient group than in the control group (p < 0.02). Significantly lower ΔtDMV and body mass index (BMI)-adjusted tDMV values [Δ(tDMV/BMI)] were observed in patients who had rerupture at the postop MRI. According to the present study, changes in DMV impact clinical outcomes after rotator cuff repair. Rehabilitation of the DMV or increasing the preop DMV values positively affects postop clinical outcomes. In addition, if the DMV is below the cutoff value during the preop period, there is insufficient improvement in clinical scores. The clinical relevance of this study is the finding that in patients with a chronic rotator cuff tear and a hypotrophic deltoid muscle, increasing the preop DMV could help achieve better functional outcomes. Prognostic, Level 3, case-control study.

Human Tendon-Derived Hydrogel Improves Healing of Chronic Tendon–Bone Interface Injuries

Grant support received from: 2016 AFSH Basic Science Grant There is no financial information to disclose. Previously our laboratory reported the positive impact of thermoresponsive, type 1 collagen–rich, decellularized human tendon-derived hydrogel (tHG) on tendon healing using a rat Achilles tendon acute injury model. We hypothesized tHG would facilitate healing of chronic injuries at tendon–bone interface (TBI) in a rotator cuff model. Rotator cuff tears are important causes of pain and disability of upper extremity and involve injury at TBI. In this study a rat chronic rotator cuff injury model was used to evaluate TBI healing after repair. Twenty Sprague–Dawley rats underwent bilateral detachment of supraspinatus (SSp) tendons. Eight weeks later, both SSp tendons were anatomically reattached to humerus. One shoulder underwent a suture to bone repair using bone tunnels (control group, n = 20) and the other underwent the same repair plus tHG injection at repair site (tHG group, n = 20). Eight weeks after repair, SSp tendon–muscle units with humeral bone were harvested after animal death. Biomechanical tests were performed on 15 samples in each group. Five additional samples in each group were evaluated via micro CT, followed by histological examinations. Paired t tests were performed for statistical analyses. Biomechanical testing revealed significantly larger load to failure (27.5 ± 11.8N vs 19.7 ± 5.4N, P = .03) and higher stiffness (15.7 ± 6.3 N/mm vs 11.5 ± 3.5 N/mm, P = .02) in the tHG group versus control. Safranin O staining showed the significantly larger area of new cartilage formation in the tHG group (0.48 ± 0.1 mm2 vs 0.32 ± 0.06 mm2, P = .03). Based on birefringence under polarized microscopy in Picosirius red–stained slides collagen fiber organization was greater in tHG group compared with the control (40.4 ± 9.8 gray scale vs 31.1 ± 4.2 gray scale, P = .07), although it did not significantly differ. Micro CT demonstrated higher bone mineral density (296.1 ± 21.9 mg/cm3 vs 274.6 ± 17.2 mg/cm3, P = .05) and larger trabecular number (1.7 ± 0.1/mm vs 1.5 ± 0.2, P = .07) at the supraspinatus insertion area of the humerus in tHG group than those in the control, although the difference did not reach statistical significance. •Injection of collagen-rich tHG at the rotator cuff repair site statistically significantly enhanced biomechanical properties and increased fibrocartilage formation at the TBI in a chronic injury model.•An improvement collagen fiber organization, higher bone mineral density, and larger trabecular number were also seen in the tHG group versus control.•This human-derived collagen gel is a promising scaffold to augment healing of chronic TBI injuries during surgical intervention. This research was supported by a Basic Science Grant from the American Foundation for Surgery of the Hand.

Interleukin-15 facilitates muscle regeneration through modulation of fibro/adipogenic progenitors

BackgroundChronic muscle injury is characteristics of fatty infiltration and fibrosis. Recently, fibro/adipogenic progenitors (FAPs) were found to be indispensable for muscular regeneration while were also responsible for fibrosis and fatty infiltration in muscle injury. Many myokines have been proven to regulate the adipose or cell proliferation. Because the fate of FAPs is largely dependent on microenvironment and the regulation of myokines on FAPs is still unclear. We screened the potential myokines and found Interleukin-15 (IL-15) may regulate the fatty infiltration in muscle injury. In this study, we investigated how IL-15 regulated FAPs in muscle injury and the effect on muscle regeneration.MethodsCell proliferation assay, western blots, qRT-PCR, immunohistochemistry, flow cytometric analysis were performed to investigate the effect of IL-15 on proliferation and adipogensis of FAPs. Acute muscle injury was induced by injection of glycerol or cardiotoxin to analyze how IL-15 effected on FAPs in vivo and its function on fatty infiltration or muscle regeneration.ResultsWe identified that the expression of IL-15 in injured muscle was negatively associated with fatty infiltration. IL-15 can stimulate the proliferation of FAPs and prevent the adipogenesis of FAPs in vitro and in vivo. The growth of FAPs caused by IL-15 was mediated through JAK-STAT pathway. In addition, desert hedgehog pathway may participate in IL-15 inhibiting adipogenesis of FAPs. Our study showed IL-15 can cause the fibrosis after muscle damage and promote the myofiber regeneration. Finally, the expression of IL-15 was positively associated with severity of fibrosis and number of FAPs in patients with chronic rotator cuff tear.ConclusionsThese findings supported the potential role of IL-15 as a modulator on fate of FAPs in injured muscle and as a novel therapy for chronic muscle injury.