Effect of Preoperative Fatty Degeneration of the Rotator Cuff Muscles on the Clinical Outcome of Patients With Intact Tendons After Arthroscopic Rotator Cuff Repair of Large/Massive Cuff Tears

Editorial Commentary: Endoscopic and Open Techniques Can Achieve Successful Outcomes With Hip Abductor Tendon Repair but Retracted Tears With High-Grade Fatty Atrophy May Benefit From an Open Approach

The gluteus medius and minimus tendon unit are commonly referred to as the "rotator cuff of the hip." Tears of the gluteus medius and/or minimus can range from interstitial, partial-thickness tears to retracted, full-thickness tears, and may result from trauma but are more commonly associated with chronic degeneration. Patients commonly present with lateral hip pain exacerbated by weight-bearing and sleeping on the affected side. In patients with persistent lateral hip pain, despite nonoperative management, both open and endoscopic gluteal tendon repair techniques have demonstrated excellent short-term and midterm clinical outcomes. However, few studies have investigated the differences in outcomes between these 2 approaches stratified by tear grade and degree of fatty atrophy. Endoscopic techniques are reported to have fewer complications; in contrast, open repairs may be a better treatment option for patients with retracted full-thickness tears because of the ability to efficiently mobilize the tendon and augment with allograft if needed. Further, the presence of high-grade fatty atrophy of the abductor musculature has been shown to predict poor outcomes after primary repair. Gluteus maximus transfer or allograft augmentation has been reserved typically for irreparable abductor tendon tears, but its ability to restore a healthy muscle tendon unit may offer improved outcomes in the setting of tears with severe fatty degeneration.

Novel 3D MRI-based volumetric assessment of rotator cuff musculature demonstrates stronger correlation with preoperative functional status when compared to the Goutallier grading scheme

BACKGROUND

The Goutallier classification (GC) is used to assess fatty atrophy in rotator cuff (RC) tears, yet limitations exist. A battery of 3-dimensional (3D) magnetic resonance imaging (MRI) volumetric scores (VSs) was developed to provide comprehensive characterization of RC pathology. The purposes of this study were to (1) describe the correlation between GC and VSs for supraspinatus changes in RC tears, (2) characterize the chronicity of RC tears using a battery of 12 VS measurements, and (3) compare GC and VSs to determine which method most closely corresponds with preoperative patient-reported outcome measures (PROMs).

METHODS

Preoperative shoulder MRIs were reviewed after arthroscopic RC repair. Preoperative GC stage and Patient-Reported Outcomes Measurement Information System (PROMIS) physical function (PF) and pain interference (PI) scores were collected. The battery of VSs included fat infiltration (FIS), muscle size (MSS), and relative volume contribution (RCS) for each RC muscle. Backward linear regression was performed to compare GC stage with preoperative PROMIS PF and PI to determine which VS measurement most closely correlated with preoperative PROMs.

RESULTS

Eighty-two patients underwent RC repair (mean age 55 ± 8.2 years, 63% male, 68% GC stage ≤1). In evaluation of the supraspinatus, there was a moderate positive correlation between GC and FIS (r = 0.459, P < .001); strong negative correlations were observed between MSS (r = -0.800, P < .001) and RCS (r = -0.745, P < .001) when compared to GC. A negligible linear correlation was observed between GC and preoperative PROMIS PF (r = -0.106, P = .343) and PI (r = -0.071, P = .528). On multivariate analysis, subscapularis MSS (β >0, P = .064) was a positive predictor and subscapularis FIS (β <0, P = .137), teres minor MSS (β <0, P = .141), and FIS (β <0, P = .070) were negative predictors of preoperative PF (r = 0.343, P = .044); in contrast, supraspinatus MSS (β >0, P = .009) and FIS (β >0, P = .073), teres minor FIS (β >0, P = .072), and subscapularis FIS (β >0, P = .065) were positive predictors of preoperative PI (r = 0.410, P = .006).

CONCLUSION

Although the criterion standard in evaluation of RC pathology, GC demonstrated negligible correlation with preoperative functional disability. Alternatively, a battery of 3D VSs showed strong correlation with GC through a quantitative, comprehensive evaluation of the RC unit including several moderate predictors of preoperative functional disability.

Quantifying Threshold Scores for Patient Satisfaction After Massive Rotator Cuff Repair for the Interpretation of Mid-Term Patient-Reported Outcomes

PURPOSE

To establish minimal clinically important difference (MCID) and patient acceptable symptomatic state (PASS) values for 4 patient-reported outcomes (PROs) in patients undergoing arthroscopic massive rotator cuff repair (aMRCR): American Shoulder and Elbow Surgeons (ASES) score, Subjective Shoulder Value (SSV), Veterans Rand-12 (VR-12) score, and the visual analog scale (VAS) pain. In addition, our study seeks to determine preoperative factors associated with achieving clinically significant improvement as defined by the MCID and PASS.

METHODS

A retrospective review at 2 institutions was performed to identify patients undergoing aMRCR with minimum 4-year follow-up. Data collected at the 1-year, 2-year, and 4-year time points included patient characteristics (age, sex, length of follow-up, tobacco use, and workers' compensation status), radiologic parameters (Goutallier fatty infiltration and modified Collin tear pattern), and 4 PRO measures (collected preoperatively and postoperatively): ASES score, SSV, VR-12 score, and VAS pain. The MCID and PASS for each outcome measure were calculated using the distribution-based method and receiver operating characteristic curve analysis, respectively. Pearson and Spearman coefficient analyses were used to determine correlations between preoperative variables and MCID or PASS thresholds.

RESULTS

A total of 101 patients with a mean follow-up of 64 months were included in the study. The MCID and PASS values at the 4-year follow-up for ASES were 14.5 and 69.4, respectively; for SSV, 13.7 and 81.5; for VR-12, 6.6 and 40.3; and for VAS pain, 1.3 and 1.2. Greater infraspinatus fatty infiltration was associated with failing to reach clinically significant values.

CONCLUSIONS

This study defined MCID and PASS values for commonly used outcome measures in patients undergoing aMRCR at the 1-year, 2-year, and 4-year follow-up. At mid-term follow-up, greater preoperative rotator cuff disease severity was associated with failure to achieve clinically significant outcomes.

LEVEL OF EVIDENCE

Level IV, case series.

[Lesions of the rotator cuff and biceps tendon]

CLINICAL/METHODOLOGICAL PROBLEM

The rotator cuff is a complex anatomical structure and the integrity is pivotal for the shoulder functionality. The pathologies are often multifactorial, resulting from degenerative, vascular, traumatic and mechanical factors.

RADIOLOGICAL STANDARD PROCEDURES

Radiography, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) form the pillars of radiological diagnostics. Each modality has specific advantages and limitations in the visualization and assessment of pathologies of the rotator cuff and biceps tendon.

METHODOLOGICAL INNOVATIONS

The MR arthrography offers additional insights in unclear cases by enhancing the differentiation between complete and partial tears.

PERFORMANCE

The MRI provides detailed information on tendon quality and associated damages, such as muscle atrophy and fat infiltration, making it the preferred method. The use of MR arthrography can identify defects through increased intra-articular pressure or contrast medium leakage.

EVALUATION

Muscle damage, as induced by edema in acute injuries or fatty degeneration in chronic conditions, can be evaluated using imaging techniques. Special attention is warranted for the infraspinatus, subscapularis and teres minor muscles due to their unique injury patterns and prevalences.

Fatty Degeneration of the Rotator Cuff Muscles Improves in Shoulders with Successful Arthroscopic Rotator Cuff Repair: A Prospective Study Using Quantitative T2 Mapping Techniques, with 2-Year Follow-up

Background

There remain arguments regarding whether fatty degeneration of the rotator cuff muscles improves following rotator cuff repair. The purpose of this study was to prospectively investigate changes in fatty degeneration of the rotator cuff muscles, quantitatively measured on magnetic resonance imaging (MRI) with use of transverse relaxation time (T2) mapping techniques, and to assess the relationship between these changes and clinical outcomes.

Methods

Patients were included if they were scheduled for arthroscopic rotator cuff repair using the suture-bridge technique between June 2014 and December 2015, underwent preoperative MRI including the T2 mapping sequence, and consented to participate in the study. Exclusion criteria consisted of trauma within 2 months before preoperative MRI, isolated subscapularis tears, patch augmentation, neuromuscular disease, and a follow-up duration of <2 years. MRI scans were acquired preoperatively and at 2 years postoperatively, and T2 values of the supraspinatus and infraspinatus muscles were measured, with smaller T2 values indicating less fat content. Shoulders were evaluated on the basis of active range of motion (ROM), Constant and University of California Los Angeles Shoulder Rating Scale scores, shoulder external rotation strength with the arm at the side, and rotator cuff integrity on postoperative MRI.

Results

A total of 103 patients (103 shoulders) with a mean age of 65 ± 9 years (range, 42 to 83 years) were included, of whom 52 were male and 51 were female. There were 13 partial, 18 small, 35 medium, 33 large, and 4 massive tears. Concomitant subscapularis tears were observed in 35 shoulders. Overall, ROM, clinical scores, and external rotation strength significantly improved postoperatively. Retears were found in 27 shoulders (26%). External rotation strength significantly improved postoperatively only in shoulders without a retear. Among shoulders without a retear, the postoperative T2 values of the supraspinatus and infraspinatus were significantly smaller than the preoperative values (p < 0.001 for both); however, no improvement was seen in shoulders with a retear.

Conclusions

Shoulders with successful repair demonstrated significantly smaller T2 values postoperatively as well as significantly improved external rotation strength. Fatty degeneration of the cuff muscles can be reversed, at least in part, and muscle strength improves in shoulders with successful repair.

Level of Evidence

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

Quantitative Assessment of Calf Muscle Volume, Strength, and Quality After Achilles Tendon Rupture Repair: A 1-Year Prospective Follow-up Study

BACKGROUND

A number of studies have reported that calf muscle atrophy is a common long-term problem after Achilles tendon repair; however, there is still a lack of data concerning early postoperative morphological changes in the calf muscle after surgery.

PURPOSE

To investigate changes over time in calf muscle volume and fatty degeneration during 1 year after Achilles tendon repair.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A prospective 1-year serial magnetic resonance imaging study was carried out with 20 patients who underwent tendon repair for unilateral acute Achilles tendon rupture. The magnetic resonance imaging assessment in addition to clinical and functional evaluations was performed at 1, 3, 6, and 12 months after surgery. The muscle volume of the medial and lateral gastrocnemius, soleus, and flexor hallucis longus (FHL) and fatty degeneration of the medial and lateral gastrocnemius and soleus were measured for the calf muscles, and the relative volume and fatty degeneration changes in the affected leg compared with the healthy contralateral leg were calculated as a percentage ([injured/healthy control] × 100) to assess structural changes over time.

RESULTS

Muscle volumes of the medial gastrocnemius, lateral gastrocnemius, soleus, and FHL were 92.3%, 92.8%, 84.6%, and 95.9% at 12 months after surgery, respectively. Medial and lateral gastrocnemius and FHL muscle volumes improved over time and recovered to almost equal to that of the healthy side at 12 months after surgery. The soleus muscle volume did not recover significantly over time and was statistically significantly smaller than that of the healthy side at 12 months (P = .029). Fatty degeneration rates of the medial gastrocnemius, lateral gastrocnemius, and soleus were 118.2%, 113.9% and 121.1% at 12 months after surgery, respectively. Fatty degeneration of the medial and lateral gastrocnemius did not change significantly, but there was a statistically significant increase in fatty degeneration of the soleus over time (P < .001).

CONCLUSION

Within the triceps surae muscle, the soleus was the most negatively affected by injury and repair for both muscle volume and fatty degeneration. Postoperative management to recover the soleus muscle function before a return to sporting activities should be considered in the future.

Arthroscopic advancement of the supraspinatus muscle and tendon for posterosuperior massive rotator cuff tears

The tension-free repair of retracted supraspinatus tears with the open muscle and tendon advancement technique first described by Debeyre in 1965 gave satisfactory clinical results. The purpose of this anatomical study was to test the feasibility of an arthroscopic supraspinatus advancement technique. A total of 10 cadaveric shoulders were operated. We assessed the feasibility, measured the slide distance, and recorded the position of the suprascapular nerve (SSN) for each shoulder. Reattachment of the tendon to its native footprint was achieved in all cases. The mean slide distance was 38.8 mm ± 3.6 (33-44). The SSN was released and tension-free in all shoulders. Arthroscopic advancement of the supraspinatus muscle and tendon enables complete rotator cuff repair in irreparable retracted posterosuperior tears and is a noteworthy alternative to the other techniques. Level of Evidence: IV.

Providing safe and effective rehabilitation by assessing supraspinatus muscle elasticity using ultrasound real-time tissue elastography after rotator cuff repair: A case series

INTRODUCTION

Although surgical techniques have advanced to avoid a postoperative re-tear after rotator cuff surgery, it remains unclear how to directly evaluate the risk of a re-tear.

OBJECTIVE

To describe how muscle elasticity with real-time tissue elastography could be used to avoid re-tear in individual cases after rotator cuff repair.

CASE DESCRIPTION

This case series included four patients, two per tear size (small and large/massive), with contrasting changes in muscle elasticity of the supraspinatus muscle. All patients underwent primary arthroscopic or open rotator cuff repair. The elasticity of the supraspinatus muscle was evaluated at relaxed and elongated positions of 0° and 60° shoulder abduction angles, respectively. The change in muscle elasticity at 1 month after surgery was characteristically different, and we predicted that a greater elasticity in the elongated position indicated a higher risk of re-tear. The cases with high risk underwent careful rehabilitation to avoid re-tear, and no re-tears were recorded in this report.

CONCLUSION

Our findings suggested that evaluation of muscle elasticity using real-time tissue elastography, which provides an indication of the risk of re-tear, in the clinical setting might be useful for therapists, who could adjust the intensity of rehabilitation, and for patients.

Comparison of the Goutallier Classification of Fatty Infiltration for the Subscapularis With a Novel Modified Classification

Background

Fatty infiltration in the subscapularis muscle extends to the upper portion of the muscle first and then to the lower portion only after some degree of fatty change has taken place in the upper region. Although the Goutallier classification is the most widely used method to categorize fatty infiltration, how to accurately and reliably determine the extent of infiltration is controversial.

Purpose

To examine a modified classification that is more reliable in (1) assessing fatty infiltration of the subscapularis muscle and (2) predicting the structural integrity of the repaired tendon by identifying cutoff points for retear.

Study Design

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

Methods

This study retrospectively examined the records of 545 patients who underwent arthroscopic repair for a subscapularis tear. Two shoulder surgeons reviewed the preoperative magnetic resonance imaging scans of all enrolled patients and evaluated the fatty infiltration of the subscapularis muscle based on the original Goutallier classification, as well as a novel modified Goutallier classification designed to measure the proportion of fat and muscle in the upper and lower portions of the muscle separately. Intra- and interobserver agreement of the reviewers was calculated using κ statistics. Using receiver operating characteristic curve analysis, we determined the cutoff point for the particular fatty infiltration grade related to the occurrence of retear for each classification scheme.

Results

The κ values for interobserver reliability were 0.743 and 0.856 for the original and modified Goutallier classifications, respectively, with the modified classification having significantly higher reliability (Z = 4.064; P < .001). Cutoff points for the fatty infiltration grade associated with retear were 2.5 for the original Goutallier classification (sensitivity, 65.3%; specificity, 95.6%; accuracy, 87.8%) and 3.5 for the modified classification (sensitivity, 52.5%; specificity, 97.8%; accuracy, 89.7%).

Conclusion

In assessing fatty infiltration of the subscapularis muscle, the modified Goutallier classification showed higher reliability than the original Goutallier classification. The cutoff point for potential retear (grade 3.5) was at a point where the fatty infiltration extended to the lower portion of the subscapularis muscle.

Correlation of defect size with fatty infiltration on MRIs of rotator cuff tendinopathy

Introduction

Sizable rotator cuff defects with limited muscle atrophy and fat replacement may represent acute traumatic ruptures that are less likely to recur after surgery to close the defect, while closure of defects with poor quality muscle are associated with defect recurrence. These distinct lesions are both referred to as tears. We analyzed the relationship between rotator cuff defect size and muscle quality to determine the relative proportion of sizable defects associated with good muscle and factors associated with muscle deterioration.

Material and methods

A cohort of 230 consecutive shoulder MRIs in patients with full-thickness rotator cuff tendon defects, limited acromioclavicular arthrosis (to avoid hindrance of defect measurement), and a duration of symptoms in the radiology report from a large urban center in the United States was evaluated for the measured distance between the supraspinatus tendon edge and the greater tuberosity medial to lateral (coronal plane defect size), anterior to posterior (sagittal plane defect width), and fatty infiltration (Goutallier classification), and atrophy (Warner classification) of the supraspinatus. We sought factors independently associated with fatty infiltration and muscle atrophy in multivariable logistic regression analyses.

Results

Forty-nine of 109 shoulders (45%) with a coronal plane defect >20 mm had reasonable muscle quality as defined by Goutallier grade less than 2 and Warner grade less than 2. Both greater fatty infiltration of the supraspinatus muscle and greater supraspinatus muscle atrophy were associated with older age and greater coronal plane defect size.

Conclusion

The observation that supraspinatus muscle health deteriorates with age and defect size, but nearly half of the largest defects had good muscle, suggests an important distinction between relatively recent traumatic ruptures and old untreated rupture or gradual attrition that may be obfuscated by referring to all lesions as tears.

Level of evidence

Level III; Retrospective diagnostic cohort.

Effect of Fatty Infiltration of the Infraspinatus Muscle on Outcomes and Graft Failure After Arthroscopic Superior Capsule Reconstruction for Irreparable Posterosuperior Rotator Cuff Tears

BACKGROUND

Superior capsule reconstruction (SCR) was developed as an alternative treatment for irreparable rotator cuff tears to restore superior stability of the glenohumeral joint. Although fatty infiltration (FI) of the rotator cuff muscles, especially the infraspinatus, has been implicated as a predictor of outcomes and graft integrity after rotator cuff repair, it has not been fully investigated in cases of SCR.

PURPOSE

To evaluate the effect of FI of the infraspinatus muscle on clinical and radiological outcomes after SCR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 55 consecutive patients with irreparable posterosuperior rotator cuff tears who underwent SCR between January 2013 and August 2020 were included retrospectively. Preoperative and postoperative clinical and radiological findings (median follow-up of >2 years), including magnetic resonance imaging results, were thoroughly reviewed. The patients were divided into 2 groups: group 1 with mild FI of the infraspinatus (Goutallier grades 0-2) and group 2 with severe FI of the infraspinatus (Goutallier grades 3-4). The American Shoulder and Elbow Surgeons score, Constant score, visual analog scale score for pain, and range of motion were evaluated. Acromiohumeral distance and rotator cuff tear arthropathy using the Hamada classification were assessed on plain radiography. Postoperative graft integrity was evaluated by magnetic resonance imaging. Graft failure was defined as complete discontinuity. Univariate and multivariable logistic regression analyses were performed to evaluate clinical and radiological findings that might be associated with successful SCR.

RESULTS

Clinical and radiological outcomes significantly improved after SCR. Graft failure was noted in 15 (27.3%) patients and was more frequent in group 2 than in group 1 (50.0% vs 14.3%, respectively; P = .004). Univariate analysis indicated a significant association between severe FI in the infraspinatus (group 2) and graft failure after SCR (odds ratio, 6.00 [95% CI, 1.65-21.80]; P = .006). Multivariable analysis indicated that FI of the infraspinatus was the only factor associated with graft failure (odds ratio, 6.37 [95% CI, 1.63-24.90]; P = .008).

CONCLUSION

Severe FI of the infraspinatus muscle was a factor indicating a poor prognosis for graft integrity after SCR. Preoperative evaluation of FI in the rotator cuff muscles can help predict postoperative outcomes and may help guide therapeutic options.

Fatty infiltration of hip muscles and trochanteric soft tissue thickness are associated with hip fractures in the elderly

PURPOSE

Apart from bone conditions, muscle and soft tissue parameters might also influence hip fractures. We aimed to evaluate the association between hip muscle and trochanteric soft tissue parameters and hip fractures.

METHODS

We retrospectively reviewed 60 patients with hip fractures and 114 controls without hip fractures. Cases and controls were matched for age, sex, and body mass index using propensity score matching. Muscle cross-sectional area (CSA), mean attenuation, and fatty infiltration rate (FIR) (proportion of intramuscular fat content) were measured on CT images for the gluteus maximus, the gluteus medius/minimus, and the anterior and medial compartments of the upper thigh. Trochanteric soft tissue thickness (TSTT) and femoral neck attenuation were also measured. Univariate and multivariate analyses were conducted to identify potential risk factors of hip fractures.

RESULTS

Patients with hip fractures had significantly lower femoral neck attenuation, TSTT, and CSA of the gluteus maximus and anterior compartment than controls. FIR of all hip muscle groups were significantly higher in hip fracture patients than controls. Multivariate analysis revealed that every 1% increase in FIR of medial compartment independently increased the odds of hip fractures by 23.7% (OR = 1.237, 95% CI = 1.093-1.401) and every 1 cm longer TSTT independently decreased the odds by 32.8% (OR = 0.672, 95% CI = 0.477-0.946).

CONCLUSION

Fatty infiltration of hip muscles can better discriminate hip fractures than muscle area. Increased TSTT is independently associated with low fracture risk.

Arthroscopic biceps augmentation does not improve clinical outcomes during incomplete repair of large to massive rotator cuff tears

AIMS

This study compared patients who underwent arthroscopic repair of large to massive rotator cuff tears (LMRCTs) with isolated incomplete repair of the tear and patients with incomplete repair with biceps tendon augmentation. We aimed to evaluate the additional benefit on clinical outcomes and the capacity to lower the re-tear rate.

METHODS

We retrospectively reviewed 1,115 patients who underwent arthroscopic rotator cuff repair for full-thickness tears between October 2011 and May 2019. From this series, we identified 77 patients (28 male, 49 female) with a mean age of 64.1 years (50 to 80). Patients were classified into groups A (n = 47 incomplete) and B (n = 30 with biceps augmentation) according to the nature of their reconstruction. Clinical scores were checked preoperatively and at six months, one year, and two years postoperatively. In preoperative MRI, we measured the tear size, the degree of fatty infiltration, and muscle volume ratio of the supraspinatus. In postoperative MRI, the integrity of the repaired rotator cuff tendon was assessed using the Sugaya classification. Tendon thickness at the footprint was evaluated on T2-weighted oblique coronal view.

RESULTS

There were no significant differences in the initial preoperative demographic characteristics. In both groups, there were significant improvements in postoperative clinical scores (p < 0.001). However, most clinical outcomes, including range of motion measurements (forward elevation, external rotation, internal rotation, and abduction), showed no differences between the pre- and postoperative values. Comparing the postoperative outcomes of both groups, no further improvement from biceps augmentation was found. Group B, although not reaching statistical significance, had more re-tears than group A (30% vs 15%; p = 0.117).

CONCLUSION

In LMRCTs, biceps augmentation provided no significant improvement of an incomplete repair. Therefore, biceps augmentation is not recommended in the treatment of LMRCTs.Cite this article: Bone Joint J 2022;104-B(11):1234-1241.

Comparison of Functional Outcomes After Arthroscopic Rotator Cuff Repair Between Patients With Traumatic and Atraumatic Tears

Background:

The role of tear etiology in outcomes after rotator cuff repair is not well understood.

Purpose/Hypothesis:

The purpose of this study was to determine the difference in outcomes after rotator cuff repair based on tear etiology. We hypothesized that traumatic rotator cuff tears will have greater improvements in functional outcome measures and range of motion (ROM) than atraumatic tears.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

We conducted a chart review of 221 consecutive patients who underwent arthroscopic rotator cuff repair; prospectively collected preoperative and minimum 2-year postoperative data were evaluated. Shoulder ROM, strength, and standard shoulder physical examination findings were recorded pre- and postoperatively. Outcome measures included visual analog scale for pain, Subjective Shoulder Value (SSV), 10-item Patient-Reported Outcomes Measurement Information System (PROMIS-10; physical and mental components), and American Shoulder and Elbow Surgeons (ASES) form.

Results:

Of the 221 patients, 73 had traumatic tears and 148 had atraumatic/degenerative tears. There were no differences in age, body mass index, or Charlson Comorbidity Index between groups. Patients in the atraumatic cohort had significantly longer duration of symptoms before presentation (18 vs 7 months; P < .01). Preoperatively, the traumatic cohort had less motion to forward flexion (mean ± SD; 138° ± 43.7° vs 152° ± 29.8°; P = .02). Postoperatively, both groups experienced significant improvements in visual analog scale and SSV scores (P < .001 each). However, only the traumatic cohort demonstrated improvements in ASES and PROMIS-10 physical component scores. Patients with traumatic rotator cuff tears had lower preoperative SSV and less motion than those with atraumatic tears, but they had greater improvements in SSV (40.6% ± 39.0% vs 29.2% ± 39.7%; P = .005) and forward flexion (21.6° ± 48.6° vs 2.3° ± 48.2°; P < .001), as well as strength in forward flexion, external rotation, and internal rotation (P < .001, P = .003, and P = .002, respectively).

Conclusion:

Patients with traumatic rotator cuff tears have worse preoperative symptoms and more functional deficits but experience greater improvements in ROM, strength, and perceived shoulder function than those with degenerative/atraumatic tears.

Prognostic factors for improvement of shoulder function after arthroscopic rotator cuff repair: a systematic review

Background

The identification of factors that specify prognostic models for postoperative results should be based on the best scientific evidence and expert assessment. We aimed to identify, map, and evaluate potential prognostic factors for the improvement of shoulder function in patients undergoing arthroscopic rotator cuff repair.

Methods

Longitudinal primary studies of arthroscopic rotator cuff repair reporting any multivariable factor analyses for shoulder function improvement with an endpoint assessment of at least 6 months were included. We systematically searched EMBASE, Medline, and Scopus for articles published between January 2014 and June 2021. The risk of bias of included studies and the quality of evidence were assessed using the Quality in Prognosis Studies tool and an adapted Grading of Recommendations, Assessment, Development, and Evaluations framework.

Results

Overall, 24 studies including 73 outcome analyses were included. We classified younger age and smaller tear size as probably prognostic for a greater improvement in objective outcomes. Shorter symptom duration, absence of a worker compensation claim, low preoperative level of functional status, and high preoperative pain level were classified as probably prognostic for greater improvement in patient-reported outcome measures. The quality of the synthesized evidence was low. Twenty-one studies had an overall high risk of bias.

Conclusion

Six potential prognostic factors for shoulder function after arthroscopic rotator cuff repair were identified. Along with ongoing expert opinion assessments, they will feed into a prognostic model-building process.

Do Age, Demographics, and Tear Characteristics Affect Outcomes After Rotator Cuff Repair? Results of Over 2000 Rotator Cuff Repairs at 5-Year Follow-up

Background:

The New Zealand Rotator Cuff Registry represents the largest prospective cohort of rotator cuff repairs. Despite this, there are limited medium- to long-term data of rotator cuff repair outcomes.

Purpose:

To (1) analyze the pain and functional outcomes of a large cohort of primary rotator cuff repairs and (2) evaluate the effect of patient factors and tear characteristics on medium-term outcomes.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

This was a multicenter, multisurgeon prospective cohort study of rotator cuff repairs from March 2009 until December 2010. Surgical data were collected by the operating surgeon. Primary outcome measures were the Flexilevel Scale of Shoulder Function (FLEX-SF) and a pain score, collected at baseline, 6, 12, and 24 months, and 5 years. Univariate and multivariate analyses were carried out.

Results:

Overall, 2533 primary rotator cuff repairs were analyzed with 81% follow-up at 5 years. The mean age of the cohort was 56 years. In the 2052 patients with final follow-up data, improvement on the FLEX-SF continued until 24 months postoperatively and remained high at 5 years. Mean improvement in FLEX-SF from baseline to 5 years was 15 points. Patients aged >70 years had lower FLEX-SF scores but no significant difference in improvement compared with patients ≤70 years. The mean anteroposterior tear size was 2.2 cm, and on multivariate analysis, tears >4 cm had worse 5-year FLEX-SF scores. If the affected tendon was easily reducible, there was no difference in FLEX-SF score for retracted or larger tears compared with smaller tears. The reoperation rate was 6.2%.

Conclusion:

Results indicated that rotator cuff repairs provide a sustained clinical improvement out past 5 years. Most functional improvement and pain relief occurred within the first 6 months, but improvement continued out to 24 months. Most population groups did well after rotator cuff repairs, including those >70 years. Tear size >4 cm and tendon reducibility correlated with outcome. Even patients with large tear sizes had clinically significant improvement in FLEX-SF scores after repair.

Clinical effect of arthroscopic long head of biceps transfer and tenodesis on irreparable rotator cuff tear

Objective

To explore the clinical effect of arthroscopic long head of biceps transfer and tenodesis for on irreparable rotator cuff tear.

Methods

A total of 18 patients with irreparable rotator cuff tear who were treated in the Dongfang Hospital Affiliated to Tongji University School of Medicine from April 2018 to March 2020 were included in this study. They all underwent arthroscopic long head of biceps transfer and tenodesis. Shoulder joint motions (forward flexion, abduction, and external rotation angle) and magnetic resonance imaging (MRI) were performed. Moreover, visual analogue scale (VAS) and university of California Los Angeles (UCLA) score were conducted during follow-up.

Results

Preoperative symptoms lasted from 3 to 16 months, with an average duration of 10 months. All patients healed in the first stage without obvious complications were included. All patients were followed up for 4 to 14 months after the surgery, with an average duration of 11.1 months. The range of shoulder joint motions, including forward flexion (80.52° ± 31.19° vs. 149.47° ± 28.36°), abduction (65.13° ± 37.59° vs. 152.46° ± 28.64°) and lateral rotation (30.17° ± 15.15° vs. 71.49° ± 11.42°) was significantly improved after operation (P < 0.05). The VAS score was notably decreased after operation (8.46 ± 0.80 vs. 1.55 ± 0.70), but the UCLA score was markedly increased (15.27 ± 2.89 vs. 31.17 ± 2.36). MRI imaging showed that 15 patients had good tissue healing, with a healing rate of 83.3% (15/18).

Conclusion

Arthroscopy of the biceps long head tendon transposition can significantly relieve pain in patients with large rotator cuff tears, improve joint mobility, and restore joint function.

Monitoring Rotator Cuff Muscle Fatty Infiltration Progression by Magnetic Resonance Imaging T1 Mapping: Correlation With Direct Evaluation Findings in Rats

BACKGROUND

Monitoring the fatty infiltration (FI) process in rotator cuff muscles is of value in establishing a treatment plan and predicting the postoperative prognosis. Quantitative T1 mapping shows promise for evaluating muscle degeneration, while its validity in monitoring rotator cuff muscle FI progression needs further investigation.

PURPOSE

To determine the validity of T1 mapping in monitoring FI progression of rotator cuff muscles.

STUDY DESIGN

Controlled laboratory study.

METHODS

Sprague-Dawley rats (N = 108) underwent left supraspinatus (SS) and infraspinatus (IS) tenotomy only (TT), suprascapular nerve transection only (NT), or SS and IS tenotomy plus suprascapular nerve transection (TT+NT). Sham surgery on the right shoulder served as the control. The magnetic resonance imaging examination included T1 mapping performed at 12, 16, and 20 weeks postoperation. SS and IS muscles were harvested to quantitatively evaluate FI via direct evaluation (triglyceride quantification assay and histological analysis) at the same predetermined intervals. The correlation of the imaging data with direct evaluation of rotator cuff muscles was analyzed.

RESULTS

T1 values were significantly lower in left SS and IS muscles at 12, 16, and 20 weeks postoperation as compared with those on the right side. T1 values of the left SS and IS muscles were continuously decreased in all groups. The TT+NT group had a greater decrease in T1 value than did the TT and NT groups. Triglyceride quantification assay and histological analysis demonstrated significant and progressive FI of the left SS and IS muscles in the 3 groups. The most serious FI changes were observed in the TT+NT group. T1 values were also well correlated with triglyceride contents and area fractions of fat.

CONCLUSION

T1 mapping can be an effective imaging modality for sensitive and quantitative monitoring of FI progression in rotator cuff muscles.

CLINICAL RELEVANCE

The findings of this study provide a tool for researchers to noninvasively and quantitatively monitor the process of muscle degeneration, contributing to the evaluation of surgical indication and postoperative prognosis.

Identification of Diagnostic Biomarkers Associated with Stromal and Immune Cell Infiltration in Fatty Infiltration After Rotator Cuff Tear by Integrating Bioinformatic Analysis and Machine-Learning

Purpose

The present study aimed to explore potential diagnostic biomarkers for fatty infiltration (FI) of the rotator cuff muscles after rotator cuff tear (RCT) and investigate the influence of stromal and immune cell infiltration on this pathology.

Methods

The GSE130447 and GSE103266 datasets were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were identified, and gene set enrichment analyses were performed by R software. Two machine learning algorithms, random forest and multiple support vector machine recursive feature elimination (mSVM-RFE), were used to screen candidate biomarkers. The diagnostic value of the screened biomarkers was further validated by the area under the ROC curve (AUC) in the GSE103266 dataset. Murine microenvironment cell population counter (mMCP-counter) method was employed to estimate stromal and immune cell infiltration of FI. The correlation between biomarkers and infiltrated immune and stromal cell subsets was further analyzed.

Results

A total of 2123 DEGs were identified. The identified DEGs were predominantly linked to immune system process, extracellular matrix organization and PPAR signalling pathway. FABP5 (AUC = 0.958) and MGP (AUC = 1) were screened as diagnostic biomarkers of FI. Stromal and immune cell infiltration analysis showed that monocytes, mast cells, vessels, endothelial cells and fibroblasts may be related to the process of FI. FABP5 and MGP were positively correlated with vessels whereas negatively correlated with monocytes and mast cells.

Conclusion

FABP5 and MGP can serve as diagnostic biomarkers of FI after RCT, and stromal and immune cell infiltration may play a crucial role in this pathology.

Muscular and Tendon Degeneration after Achilles Rupture: New Insights into Future Repair Strategies

Achilles tendon rupture is a frequent injury with an increasing incidence. After clinical surgical repair, aimed at suturing the tendon stumps back into their original position, the repaired Achilles tendon is often plastically deformed and mechanically less strong than the pre-injured tissue, with muscle fatty degeneration contributing to function loss. Despite clinical outcomes, pre-clinical research has mainly focused on tendon structural repair, with a lack of knowledge regarding injury progression from tendon to muscle and its consequences on muscle degenerative/regenerative processes and function. Here, we characterize the morphological changes in the tendon, the myotendinous junction and muscle belly in a mouse model of Achilles tendon complete rupture, finding cellular and fatty infiltration, fibrotic tissue accumulation, muscle stem cell decline and collagen fiber disorganization. We use novel imaging technologies to accurately relate structural alterations in tendon fibers to pathological changes, which further explain the loss of muscle mechanical function after tendon rupture. The treatment of tendon injuries remains a challenge for orthopedics. Thus, the main goal of this study is to bridge the gap between clinicians’ knowledge and research to address the underlying pathophysiology of ruptured Achilles tendon and its consequences in the gastrocnemius. Such studies are necessary if current practices in regenerative medicine for Achilles tendon ruptures are to be improved.

Fatty degeneration of the rotator cuff: pathogenesis, clinical implications, and future treatment

Chronic rotator cuff pathology is often complicated by fatty degeneration of the rotator cuff (FDRC) muscles, an insidious process associated with poor prognosis with or without surgical intervention. Currently there is no treatment for FDRC, and many studies have described a natural course for this disease almost always resulting in further degeneration and morbidity. Recapitulating FDRC using animal injury models, and using imaging-based studies of human FDRC, the pathophysiology of this disease continues to be further characterized. Researchers studying mesenchymal stem cell-derived progenitor cells and known fibrogenic and adipogenic signaling pathways implicated in FDRC seek to clarify the underlying processes driving these changes. While new cell- and molecular-based therapies are being developed, currently the strongest available avenue for improved management of FDRC is the use of novel imaging techniques which allow for more accurate and personalized staging of fatty degeneration. This narrative review summarizes the evidence on the molecular and pathophysiologic mechanisms of FDRC and provides a clinical update on the diagnosis and management of this condition based on the existing knowledge. We also sought to examine the role of newer biologic therapies in the management of RC fatty degeneration and to identify areas of future research.

Functional and Structural Outcomes After Retears of Arthroscopically Repaired Large and Massive Rotator Cuff Tears

Background:

Most studies have shown acceptable clinical results in patients with large or massive tears treated by arthroscopic rotator cuff repair (ARCR); however, the effects of retears after surgery in these patients remain unknown.

Purpose:

To evaluate functional and structural outcomes after retears of large and massive rotator cuff tears treated by ARCR.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 196 consecutive patients with large to massive rotator cuff tears underwent physical examination and magnetic resonance imaging before and after ARCR at 6, 12, and 24 months. Of these, 9 patients were lost at 6 months after surgery. Therefore, 187 patients were followed up for 24 months after surgery; 148 patients showed no postsurgical ruptures. Consequently, the remaining 39 patients with postsurgical ruptures were included in this study (mean age at surgery, 64.2 ± 8.7 years). Functional outcome measures comprised the University of California, Los Angeles (UCLA) and Japanese Orthopaedic Association (JOA) scores. Structural outcome measures consisted of the global fatty degeneration index (GFDI), mediolateral tear size, and residual tendon attachment area as evaluated by our own scoring system.

Results:

The mean UCLA and JOA scores significantly improved from 16.3 ± 3.9 and 63.2 ± 10.7 preoperatively to 27.9 ± 5.5 (P < .0001) and 84.5 ± 9.4 (P < .0001) at final follow-up, respectively. The mean mediolateral tear size (P = .03, .02, and .02, respectively) and residual tendon attachment area (P = .04, .03, and .04, respectively) significantly improved from preoperatively to 6, 12, and 24 months postoperatively. The correlation analysis between the functional and structural variables confirmed significant associations between the residual tendon attachment area, the JOA and UCLA scores at 24 months postoperatively, and the preoperative GFDI (r = –0.81 to 0.78).

Conclusion:

The residual tendon attachment area after a retear was significantly larger at 24 months after surgery than before surgery. In addition, significant associations were confirmed between preoperative fatty degeneration, the residual tendon attachment area, and functional outcomes after a retear. These results may explain why functional outcomes significantly improved even after retears in this series.

Midterm Functional and Structural Outcomes of Large/Massive Cuff Tears Treated by Arthroscopic Partial Repair

Background:

Previous studies have shown good clinical outcomes in patients with irreparable large or massive rotator cuff tears treated using arthroscopic partial repair (APR); however, few studies have evaluated both functional and structural outcomes in these patients.

Purpose:

To evaluate both functional and structural outcomes in patients with large or massive rotator cuff tears treated using APR.

Study Design:

Case series; Level of evidence, 4.

Methods:

Between March 2009 and November 2016, a total of 30 patients underwent APR because of the irreparability of their large or massive rotator cuff tears during surgery. Of these patients, 24 completed the minimum 24-month follow-up (mean, 61.8 ± 27.1 months; range, 24-112 months) and were included in this study. Functional outcome measures included the Japanese Orthopaedic Association (JOA) and University of California Los Angeles (UCLA) scores and the visual analog scale for pain. Structural outcome measures comprised preoperative fatty degeneration, mediolateral tear size, residual tendon attachment area, and glenohumeral (GH) arthritic changes evaluated on magnetic resonance imaging scans or plain radiographs before and after surgery. Functional and structural outcomes were evaluated preoperatively, at 3 months postoperatively, and at the final follow-up.

Results:

The JOA scores for all patients significantly improved from 67.9 ± 11.3 preoperatively to 85.4 ± 15.6 postoperatively (P < .0001). Similarly, the UCLA scores significantly improved from 15.8 ± 4.20 preoperatively to 29 ± 6.69 at final follow-up postoperatively (P < .0001). The mediolateral tear size were significantly decreased at 3 months postoperatively (P < .001) and at the final follow-up (P < .001). Compared with preoperative scores, the novel score evaluating the residual tendon attachment area improved from 3.08 ± 0.46 to 3.54 ± 0.41 (P < .001) after surgery overall, although it significantly deteriorated from 3 months postoperatively to the final follow-up. GH osteoarthritis progressed in 6 patients (25%). Patients who developed osteoarthritis had lower JOA and UCLA scores than did those who did not (JOA, P = .010; UCLA, P = .037).

Conclusion:

In irreparable large or massive rotator cuff tears treated using APR, functional outcome improved after surgery. Although the residual tendon attachment area improved, functional outcome after APR corresponded to the GH alterations at the midterm follow-up. Longer-term follow-up is needed to further elucidate the effect of APR on clinical outcomes in these patients.

Ultrasound shear wave elastography and its association with rotator cuff tear characteristics

Background

Approximately 20-60% of rotator cuff repairs fail with higher failure rates in patients with larger or more chronic tears. Although MRI provides an objective estimate of tear size, it can only provide qualitative descriptions of tear chronicity. By contrast, ultrasound shear wave elastography (SWE) may assess tear chronicity by estimating tissue mechanical properties (ie, shear modulus). Furthermore, SWE imaging does not share many of the challenges associated with MRI (eg, high cost, risk of claustrophobia). Therefore, the objective of this study was to determine the extent to which estimated supraspinatus shear modulus is associated with conventional MRI-based measures of rotator cuff tear size and chronicity.

Methods

Shear modulus was estimated using ultrasound SWE in two regions of the supraspinatus (intramuscular tendon, muscle belly) under two contractile conditions (passive, active) in 22 participants with full-thickness rotator cuff tears. The extent to which estimated supraspinatus shear modulus is associated with conventional MRI measures of tear size and chronicity was assessed using correlation coefficients and Kruskal-Wallis tests, as appropriate.

Results

Estimated shear modulus was not significantly associated with anterior/posterior tear size (P > .09), tear retraction (P > .20), occupation ratio (P > .11), or fatty infiltration (P > .30) under any testing condition.

Discussion

Although ultrasound SWE measurements have been shown to be altered in the presence of various tendinopathies, the findings of this study suggest the utility of ultrasound SWE in this population (ie, patients with a small to medium supraspinatus rotator cuff tear) before surgical rotator cuff repair remains unclear.

New quantified measurement of fatty infiltration of the rotator cuff muscles using magnetic resonance imaging

BACKGROUND

The degree of fatty infiltration of the rotator cuff muscle is typically evaluated using the Goutallier-Fuchs grading system, but its consistency remains controversial. This study aimed to evaluate a new quantified measurement of fatty infiltration based on three-dimensionally reconstructed volumetric data obtained from magnetic resonance images of non-pathologic shoulders using open-source software.

METHODS

Fourteen shoulder 3-T magnetic resonance images (8 men, 6 women) without lesions obtained between 2010 and 2017 were analysed. Slicer version 4.6.2 was used to semi-automatically reconstruct the three-dimensional volumetric data from T2 sagittal oblique images and to differentiate fat tissue from rotator cuff muscle using the difference in signal intensity.

RESULTS

The cutoff value for dividing muscle and fat was 508.9. The inter-class and intra-class correlations of each rotator cuff muscle and fat tissue were >0.9 (all P < 0.001). The mean muscle volume of the supraspinatus, infraspinatus, teres minor, and subscapularis were 15.2, 20.9, 13.3, and 29.7 mL, respectively. The muscle volume of the men was greater than that of the women (all P < 0.001), and the fat infiltration ratio was positively correlated with body mass index (all P < 0.05).

CONCLUSIONS

The semi-automated quantified measurement of fatty infiltration of the rotator cuff muscles using magnetic resonance imaging and Slicer software presented excellent consistency. This technique could be an alternative measurement to complement the weak consistency of the Goutallier-Fuchs grading system. However, to reduce the error of measurement, this study evaluated non-pathologic shoulders. Therefore, further study using magnetic resonance imaging of pathologic shoulders is necessary for actual clinical application.

LEVEL OF EVIDENCE

Level IV, case series, diagnostic study.

Glenoid Retroversion Associates With Asymmetric Rotator Cuff Muscle Atrophy in Those With Walch B-type Glenohumeral Osteoarthritis

BACKGROUND

Our purpose was to determine whether glenoid retroversion associates with asymmetric rotator cuff muscle atrophy in eccentric glenohumeral osteoarthritis (GHOA) and if this asymmetry is worsening of GHOA-related atrophy.

METHODS

Two groups of shoulder magnetic resonance images were studied: patients older than 50 years without a rotator cuff tear or GHOA (control group) and patients preoperative to anatomic total shoulder arthroplasty (GHOA group). Retroversion and rotator cuff muscle cross-sectional areas were measured using reliable and accurate techniques. Proportional muscle areas were created by dividing by total cuff area to correct for differences in overall patient size. Walch grades were assigned via consensus.

RESULTS

The control group consisted of 102 patients and the GHOA cohort consisted of 141 patients. Within the eccentric GHOA group, retroversion associated with relative increasing supraspinatus (r = 0.268, P = 0.035), increasing infraspinatus (r = 0.273, P = 0.032), and decreasing subscapularis areas (r = -0.343, P = 0.006). However, the combined GHOA group had a significantly higher relative subscapularis area than the control group (P = 0.026).

CONCLUSION

In the eccentric GHOA, increasing retroversion is associated with increasing volume of the posterior cuff relative to the anterior cuff muscles, which is a reversal of the asymmetric increasing volume of the anterior cuff relative to the posterior cuff muscles seen with concentric GHOA.

LEVEL OF EVIDENCE

Diagnostic, level III.

Fatty degeneration and wnt10b expression in the supraspinatus muscle after surgical repair of torn rotator cuff tendon

PURPOSE

In the torn rotator cuff muscles, decreased expression of wnt10b prior to elevation of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα) has previously been reported. The purpose of this study is to elucidate the expression profiles of these adipogenesis-related genes after rotator cuff detachment and reattachment in a rabbit model.

METHODS

We investigated gene expression profiles of PPARγ, C/EBPα, and wnt10b in different parts of rabbit supraspinatus (SSP) muscle after tendon detachment (n = 6 for each time point). In addition, we assessed expression of the same genes after SSP reattachment with different intervals from initial detachment (n = 6). Fatty degeneration of the SSP muscle was examined by Oil red-O staining. Gene expression profiles were examined by quantitative real-time polymerase chain reaction.

RESULTS

After SSP detachment, Oil red-O-positive oil deposits increased after 3 weeks. In the SSP reattachment model, numerous Oil red-O-positive cells were present at 5-week reattachment, following 2- and 3-week detachment. PPARγ and C/EBPα messenger ribonucleic acid expression exhibited a significant increase at 2 and 3 weeks after SSP detachment and remained increased at 5-week reattachment after 2- and 3-week detachment. A decreased expression of wnt10b was observed from 1 week after SSP detachment. Expression of wnt10b was recovered not in the central area of the SSP muscle but in the periphery after reattachment. Adipogenic change was not observed when SSP tendon was reattached after 1-week detachment.

CONCLUSIONS

These results may suggest that once the adipogenic transcription factors, PPARγ and C/EBPα, were elevated, repair surgery after rotator cuff tear could not prevent the emergence of fat in the SSP muscle.

Adipose Stem Cell-Derived Exosomes Decrease Fatty Infiltration and Enhance Rotator Cuff Healing in a Rabbit Model of Chronic Tears

BACKGROUND

Fatty infiltration and poor tendon-bone healing in chronic rotator cuff tears (RCTs) are associated with unsatisfactory prognosis. Adipose stem cell-derived exosomes (ASC-Exos), having multiple biological effects, can prevent muscle degeneration in acute RCTs. However, the effects of ASC-Exos on fatty infiltration and tendon-bone healing in chronic RCTs remain unknown.

PURPOSE

To study the effects of ASC-Exos on fatty infiltration and tendon-bone healing in a chronic RCT rabbit model.

STUDY DESIGN

Controlled laboratory study.

METHODS

At week 0, we randomly allocated 35 rabbits to receive sham surgery (14 rabbits) or establish a bilateral RCT model (21 rabbits, detachment of the supraspinatus tendon). At week 6, a total of 7 rabbits received sham surgery, and 7 rabbits with RCT were sacrificed for fatty infiltration assay. The remaining 14 rabbits with bilateral RCTs were randomly assigned to a saline group (7 rabbits that received local saline injection and rotator cuff repair) or an ASC-Exos group (7 rabbits that received local ASC-Exos injection and rotator cuff repair). At week 18, all rabbits were sacrificed for histological examination and biomechanical testing.

RESULTS

At week 18, the ASC-Exos group showed significantly lower fatty infiltration (14.01% ± 2.85%) compared with the saline group (21.79% ± 3.07%) (P < .001), and no statistical difference compared with the time of repair (10.88% ± 2.64%) (P = .127). For tendon-bone healing, the ASC-Exos group showed a higher histological score and more newly regenerated fibrocartilage at the repair site than did the saline group. Regarding biomechanical testing, the ASC-Exos group showed significantly higher ultimate load to failure, stiffness, and stress than the saline group.

CONCLUSION

Local injection of ASC-Exos in chronic RCTs at the time of repair could prevent the progress of fatty infiltration, promote tendon-bone healing, and improve biomechanical properties.

CLINICAL RELEVANCE

ASC-Exos injection may be used as a cell-free adjunctive therapy to inhibit fatty infiltration and improve rotator cuff healing in the repair of chronic RCTs.

Do Outcomes of Arthroscopic Subscapularis Tendon Repairs Depend on Rotator Cuff Fatty Infiltration?

Background:

Rotator cuff fatty infiltration has been correlated with poorer radiographic and clinical outcomes in supraspinatus and infraspinatus tendon repairs, but this has not been well-studied in subscapularis tendon repairs.

Purpose:

To evaluate the influence of preoperative rotator cuff fatty infiltration on postoperative outcomes for patients undergoing arthroscopic subscapularis tendon repair.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients who underwent arthroscopic subscapularis repair between 2010 and 2016 were retrospectively identified, and demographic data and surgical findings were recorded. The extent of fatty infiltration was determined on preoperative magnetic resonance imaging by the Fuchs modification of the Goutallier classification. At the most recent follow-up, patients completed the Patient-Reported Outcomes Measurement Information System for Upper Extremity (PROMIS-UE) computer adaptive test and a postoperative visual analog scale for pain. The distribution of fatty infiltration was compared between patients undergoing subscapularis tendon repair versus subscapularis tendon repair combined with a posterior cuff repair. Outcomes were compared for patients using Goutallier grade 0-1 versus grade ≥2 changes in each rotator cuff muscle. Multivariate linear regression analysis was performed to evaluate the influence of muscle quality, as well as demographic factors, on PROMIS-UE scores. Significance was defined as P < .05.

Results:

There were 140 shoulders included (mean age, 61.8 years; 42.1% female; mean follow-up, 51.7 months). The prevalence of Goutallier grade 2 changes or higher was significantly greater in patients with multitendon repair relative to isolated subscapularis tendon repair. For the overall group of all patients undergoing subscapularis tendon repair, whether in isolation or as part of a multitendon repair, PROMIS-UE scores were significantly lower for patients with infraspinatus muscle grade 2 or higher Goutallier changes relative to grade 0 or 1. After adjustment for age, body mass index, patient sex, and fatty infiltration in other rotator cuff muscles, poor infraspinatus muscle quality remained the only significant predictor for lower PROMIS-UE scores.

Conclusion:

Patients undergoing arthroscopic subscapularis tendon repair with poor infraspinatus muscle quality had worse patient-reported outcomes. This was true whether subscapularis tendon repair was isolated or was performed in conjunction with supraspinatus and infraspinatus tendon repairs.

Clinical and structural outcome 20 years after repair of massive rotator cuff tears

BACKGROUND

Short- and mid-term outcomes after massive cuff tear repair are well reported, but there is no documentation of the clinical and structural outcomes at 20 years of follow-up. The hypothesis of the present study was that at 20 years, deterioration of the shoulder would have occurred and led to a substantial number of reoperations.

METHODS

The authors retrospectively recalled all 127 patients operated for massive rotator cuff tears in 1994 at 6 different centers. At the 20-year follow-up, 26 patients died and 35 were lost to follow-up. Thirteen (10.2%) had been reoperated. This left 53 patients for personal clinical assessment. Forty-nine consented to standardized radiographic evaluation for assessment of osteoarthritis, 36 patients underwent magnetic resonance imaging, allowing assessment of tendon healing, atrophy, and fatty infiltration (FI) of the cuff muscles.

RESULTS

The final Constant-Murley score (CS) was 68 ± 17.7 (range, 8-91) vs. 44 ± 15.3 (range, 13-74) preoperatively (P < .05). The final Subjective Shoulder Value (SSV) was 73% ± 23% (range, 0-100). Retears (Sugaya IV and V) were found in 17 cases (47%). Nine patients (17%) had cuff tear arthropathy (Hamada stage 4). The CS and SSV for the shoulders with FI stages III or IV were significantly inferior (53 ± 19 points and 65% ± 14% respectively) than for those with FI stages 0-II (respectively, 71.6 ± 6 points and 73% ± 4%) (P < .05).

CONCLUSIONS

Twenty years after surgical repair of massive rotator cuff tears, the functional scores remain satisfactory, and the rate of revision is low.

Nerve and Muscle Abnormalities

Muscle atrophy in shoulders with rotator cuff tendon tears is a negative prognosticator, associated with decreased function, decreased reparability, increased retears after repair, and poorer outcomes after surgery. Muscle edema or atrophy within a neurologic distribution characterizes denervation. Because most nerve entrapments around the shoulder are not caused by mass lesions and show no nerve findings on routine MR imaging sequences, pattern of muscle denervation is often the best clue to predicting location of nerve dysfunction, which narrows the differential diagnosis and guides clinical management. The exception is suprascapular nerve compression in the spinoglenoid notch caused by a compressing cyst.

Clinical and radiological outcomes of osteoarthritis twenty years after rotator cuff repair

PURPOSE

Outcomes of open or arthroscopic rotator cuff repairs are well reported in the literature. The purpose of the study was to evaluate the prevalence and clinical impact of osteoarthritis 20 years following rotator cuff repair. The hypothesis was that, at long follow-up, most shoulders would have developed gleno-humeral osteoarthritis.

METHODS

The authors retrospectively recalled all 322 patients, operated for rotator cuff tears in 1994 at 6 different centres, for clinical and radiographic assessment. At 20 years of follow-up, 24 were re-operated (5 arthroplasty) and 53.4% were lost to follow-up. This left 126 patients, had been clinically assessed, had Magnetic Resonance Images (MRI) that allowed anatomic assessment of tendon healing (Sugaya), fatty infiltration (Goutallier), and X rays in order to analyse arthritis without head migration (Samilson) and with head migration (Hamada and Fukuda). Only patients with complete data were selected.

RESULTS

Mean aged was 52.3 years (25.3-68.6) at index operation. The Constant score was 45.3±19.6 preoperatively to 67.4±18.7 points at 20 years. The SSV was 73.5±21 postoperatively. The rate of osteoarthritis was 29%. Osteoarthritis was associated with a significant inferior Constant score compared to the non-arthritic group (61 versus 71 points, p=0.02), mainly due to a significant lower strength (5.4 versus 8.7 points, p=0.007). Massive rotator cuff tears were significantly associated with a higher rate of osteoarthritis. Only 4,8% patients after cuff repear needed a reverse shoulder arthroplasty. Significantly less osteoarthritis was observed when the rotator cuff repair remained intact. Suprasupinatus retear had a significant influence on fatty infiltration of the infrasupinatus muscle and on the progression towards osteoarthritis.

CONCLUSION

Twenty years after open rotator cuff repair, the rate of osteoarthritis was 29%. Massive rotator cuff tears were significantly associated with a higher rate of osteoarthritis. Less osteoarthritis was observed when suprasupinatus healed.

LEVEL OF EVIDENCE

IV.

Optimizing methods to quantify intramuscular fat in rotator cuff tears with normalization

OBJECTIVE

To determine which normalization method may best account for confounding individual factors, such as age or BMI, when quantifying fat infiltration on MRI in patients with rotator cuff tears, the effects of normalization using three different muscles (teres major; triceps brachii; teres minor) were compared.

METHODS

Thirty-seven consecutive patients diagnosed with rotator cuff pathology were included. MRI fat-water sequences were used to quantify rotator cuff intramuscular fat (%fat). Three reference muscles (teres major, triceps, teres minor) were used to derive normalized %fat. Relationships between intramuscular %fat and tear size, age, and BMI in each rotator cuff muscle, before and after normalization, were compared with Fisher transformations (α = 0.05).

RESULTS

Normalization with teres major ameliorated confounding relationships of age and BMI on rotator cuff %fat. In contrast, normalization with triceps maintained the confounding relationships between %fat and age in supraspinatus (p = 0.03) and infraspinatus/teres minor (p = 0.028). Normalization with teres minor maintained the confounding relationship between %fat and BMI in subscapularis (p = 0.039). Normalization with teres major best-maintained relationships between tear size and infraspinatus/teres minor %fat (p = 0.021). In contrast, normalization with triceps or teres minor eliminated all significant relationships with tear size.

CONCLUSIONS

Results of this pilot study suggest normalization to teres major using MRI-based %fat quantification methods can effectively control for individual factors, such as BMI or age, and may have utility in evaluating and monitoring rotator cuff fat infiltration attributed specifically to a tendon tear.

Lower Trapezius Tendon Transfer for Massive Irreparable Rotator Cuff Tears

The treatment of the massive irreparable rotator cuff tear poses a challenging problem. Tendon transfers offer a solution for irreparable posterosuperior rotator cuff tears. The lower trapezius tendon transfer with incorporation of an Achilles tendon allograft has emerged as an effective way to restore strength and function in select patients. Both open and arthroscopic-assisted techniques have been described.

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

PURPOSE

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.

METHODS

A total of 54 patients (35 females, 19 males) between 40 and 70 years of age who underwent single-row arthroscopic repair due to chronic rotator cuff tears were compared via preoperative (preop) and postoperative (postop) (6-12 months) 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.

RESULTS

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.

CONCLUSIONS

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.

LEVEL OF EVIDENCE

Prognostic, Level 3, case-control study.

Gene Expression Patterns Analysis in the Supraspinatus Muscle after a Rotator Cuff Tear in a Mouse Model

Rotator cuff tear is a muscle-tendinous injury representative of various musculoskeletal disorders. In general, rotator cuff tear occurs in the tendon, but it causes unloading of the muscle resulting in muscle degeneration including fatty infiltration. These muscle degenerations lead to muscle weakness, pain, and loss of shoulder function and are well known as important factors for poor functional outcome after rotator cuff repair. Given that rotator cuff tear in various animal species results in similar pathological changes seen in humans, the animal model can be considered a good approach to understand the many aspects of the molecular changes in injured muscle. To comprehensively analyze changes in gene expression with time following a rotator cuff tear, we established a rotator cuff tear in mouse supraspinatus tendon of shoulder. At weeks 1 and 4 after the tear, the injured muscles were harvested for RNA isolation, and microarray analysis was performed. Expression patterns of genes belonging to 10 muscle physiology-related categories, including aging, apoptosis, atrophy, and fatty acid transport, were analyzed and further validated using real-time PCR. A total of 39,429 genes were analyzed, and significant changes in expression were observed for 12,178 genes at 1 week and 2,370 genes at 4 weeks after the tear. From the list of top 10 significantly up- and downregulated genes at the 2 time periods and the network evaluation of relevant genes according to the 10 categories, several important genes in each category were observed. In this study, we found that various genes are significantly altered after rotator cuff tear, and these genes may play key roles in controlling muscle degeneration after a rotator cuff tear.

Prognostic factors affecting clinical outcomes after arthroscopic rotator cuff repair: importance of functional recovery by 3 months after surgery

BACKGROUND

To examine important factors that affect clinical outcomes following arthroscopic rotator cuff repair (ARCR).

METHODS

Among 163 patients who underwent ARCR, we included 71 shoulders in 71 patients whose progress was monitored for > 2 years, postoperatively. We divided the patients into groups A (scores ≥ 83 points, 59 patients) and B (scores < 83 points, 12 patients) using the Japanese Orthopedic Association (JOA) score at 24 months. We then conducted univariate and multivariate analyses of pre- and postoperative (2 and 3 months, respectively) factors.

RESULTS

The mean JOA score for all patients significantly improved from 63.7 ± 11.5 points preoperatively to 90.3 ± 9.6 points at 24 months postoperatively (P < 0.05). However, there were no significant between-group differences in the preoperative scores. In addition, there were no significant differences in the postoperative re-tear rate. Univariate analysis revealed that the range of motion (preoperative abduction and postoperative elevation, abduction, internal rotation, and external rotation), muscle strength (external rotation 3 months postoperatively), postoperative pain level [visual analog scale (VAS) maximum score, 10 points], partial repair, Cofield classification, and preoperative width were significant factors (P < 0.05 for all factors). Multivariate and receiver operating characteristic curve analyses showed that VAS at 2 months postoperatively and elevation at 3 months postoperatively were significant factors.

CONCLUSIONS

To obtain a JOA score of ≥ 83 points at 24 months postoperatively, following ARCR, a postoperative VAS of < 5 points at 2 months and postoperative elevation of ≥ 110° at 3 months should be achieved.

Clinical and structural outcomes after arthroscopic rotator cuff repair: a comparison between suture bridge techniques with or without medial knot tying

Purpose

To compare arthroscopic suture bridge (SB) techniques with medial tying to those without tying, considering clinical and structural outcomes.

Methods

We included 124 patients with rotator cuff tears after arthroscopic rotator cuff repair (ARCR). Fifty-three patients with clinical and structural evaluations 3, 12, and 24 months postoperatively were included and divided into 29 patients with medial tying (WMT group) and 24 without tying (WOMT group). Clinical outcomes comprised the University of California Los Angeles (UCLA) and Japanese Orthopaedic Association (JOA) scores. Structural outcomes were evaluated with magnetic resonance images (MRI) using Sugaya classifications.

Results

JOA and UCLA scores in the WMT and WOMT groups improved significantly from before surgery to 24 months after surgery (P < 0.01, respectively). No significant difference was noted between groups. No significant postoperative retears (Sugaya types 4 and 5) between WMT and WOMT groups were noted at 3 months (5 vs 3 cases), 12 months (6 vs 5 cases), and 24 months (7 vs 6 cases) postoperatively. Complete healing (Sugaya type 1) was noted at 3 months (8 vs 11 cases), 12 months (10 vs 10 cases), and 24 months (8 vs 13 cases, P = 0.024) postoperatively. Incomplete healing (Sugaya types 2 and 3) were noted at 3 months (16 vs 10 cases), 12 months (13 vs 9 cases), and 24 months (14 vs 5 cases, P = 0.024) postoperatively.

Conclusion

Clinical outcomes for both techniques were comparable, but the number of incompletely healed tendons in SB with medial tying was significantly larger at 24 months after surgery.

Level of evidence

This study is a level III, case-control study.

Clinical relevance

This study revealed the influence of medial tying in rotator cuff repair.

A Mouse Model of Delayed Rotator Cuff Repair Results in Persistent Muscle Atrophy and Fatty Infiltration

BACKGROUND

Rotator cuff (RC) tears are common tendon injuries seen in orthopaedic patients. Successful repair of large and massive RC tears remains a challenge due to our limited understanding of the pathophysiological features of this injury. Clinically relevant small animal models that can be used to study the pathophysiological response to repair are limited by the lack of chronic repair models.

PURPOSE

To develop a highly clinically relevant mouse model of delayed RC repair.

STUDY DESIGN

Controlled laboratory study.

METHODS

Three-month-old C57BL/6J mice underwent unilateral supraspinatus (SS) and infraspinatus (IS) tendon tear with immediate, 2-week delayed, or 6-week delayed tendon repair. Animals with no repair or sham surgery served as controls. Gait analysis was conducted to measure shoulder function at 2 weeks and 6 weeks after surgery. Animals were sacrificed 6 weeks after the last surgery. Shoulder joint, SS, and IS muscles were harvested and analyzed histologically. Ex vivo mechanical testing of intact and repaired SS and IS tendons was conducted. Reverse-transcriptase polymerase chain reaction was performed on SS and IS muscles to quantify atrophy, fibrosis, and fatty infiltration-related gene expression.

RESULTS

Histological and tendon mechanical testing showed that torn tendons could be successfully repaired as late as 6 weeks after transection. However, significant atrophy and fatty infiltration of muscle, with impaired shoulder function, were persistent in the 6-week delayed repair group. Shoulder function correlated with the severity of RC muscle weight loss and fatty infiltration.

CONCLUSION

We successfully developed a clinically relevant mouse model of delayed RC repair. Six-week delayed RC repair resulted in persistent muscle atrophy and fatty infiltration with inferior shoulder function compared with acute repair.

CLINICAL RELEVANCE

Our novel mouse model could serve as a powerful tool to understand the pathophysiological and cellular/molecular mechanisms of RC muscle and tendon degeneration, eventually improving our strategies for treating and repairing RC tears.

Options for Failed Rotator Cuff Repair

Failed rotator cuff repairs can pose a clinical challenge to the treating orthopedic surgeon. There are many nonsurgical and surgical options available to address the failed rotator cuff repair. Surgical options include revising the primary repair, partial or nonanatomic repair, tendon transfer, biological augmentation or use of tissue-engineered grafts for reconstruction, or total joint arthroplasty (typically with a modern reverse total shoulder arthroplasty system). The treating surgeon must assess the patient's functional status, health status, and expectations in order to customize the appropriate treatment plan for addressing the failed rotator cuff repair. With the abundance of treatment options available, there is typically an adequate solution to help the patient regain function and experience less pain.

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

Background

Chronic 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.

Methods

Cell 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.

Results

We 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.

Conclusions

These 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.

Electronic supplementary material

The online version of this article (10.1186/s12964-018-0251-0) contains supplementary material, which is available to authorized users.

Grade of retraction and tendon thickness correlates with MR-spectroscopically measured amount of fatty degeneration in full thickness supraspinatus tears

Background

The amount of fatty degeneration (FD) has major impact on the clinical result and cuff integrity after rotator cuff repair. A quantitative analysis with magnet resonance imaging (MRI) spectroscopy was employed to analyze possible correlation of FD with tendon retraction, tendon thickness and patients’ characteristics in full thickness supraspinatus tears.

Methods

Forty-two patients with full-thickness supraspinatus tears underwent shoulder MRI including an experimental spectroscopic sequence allowing quantification of the fat fraction in the supraspinatus muscle belly. The amount of fatty degeneration was correlated with tendon retraction, tendon thickness, patients’ age, gender, smoker status, symptom duration and body mass index (BMI). Patients were divided in to three groups of retraction (A) 0-10 mm (n=), (B) 11-20 mm (n=) and (C) < 21 mm (n=) and the means of FD for each group were calculated.

Results

Tendon retraction (R = 0.6) and symptom duration (R = 0.6) correlated positively, whereas tendon thickness correlated negatively (R = − 0.6) with the amount of FD. The fat fraction increased significantly with tendon retraction: Group (A) showed a mean fat mount of 3.7% (±4%), group (B) of 16.7% (±8.2%) and group (C) of 37.5% (±19%). BMI, age and smoker-status only showed weak to moderate correlation with the amount of FD in this cohort.

Conclusion

MRI spectroscopy revealed significantly higher amount of fat with increasing grade of retraction, symptom duration and decreased tendon thickness. Thus, these parameters may indirectly be associated with the severity of tendon disease.

Novel Arthroscopic Tendon Transfers for Posterosuperior Rotator Cuff Tears: Latissimus Dorsi and Lower Trapezius Transfers

Background

Massive irreparable rotator cuff tears in both the primary and the revision setting are challenging problems. There remains controversy over the ideal treatment methods for these patients. In the case of an irreparable posterosuperior rotator cuff tear, tendon transfers^1-12 have emerged as a reliable option, with a durable outcome. The most commonly used tendon transfer options are the latissimus dorsi (LD)^1-6and the lower trapezius (LT)¹².

Description

The LD transfer is performed by first harvesting the LT tendon from the humeral shaft. It is critical to release the many adhesions to the muscle belly as well as to separate it from the teres major muscle. The tendon is then transferred intra-articularly, in an interval between the deltoid and the teres minor. The tendon is anchored arthroscopically after preparation of the anterolateral aspect of the tuberosity. The LT transfer is performed by harvesting the LT muscle and tendon off its insertion on the medial aspect of the scapular spine. It should be mobilized to maximize excursion by releasing adhesions. An Achilles tendon allograft is anchored into the anterior aspect of the greater tuberosity arthroscopically. The Achilles tendon is then secured to the LT tendon.

Alternatives

In addition to tendon transfer, options include:Partial or complete attempted repair^13-17.Augmentation or bridging with allografts^18-23.Superior capsular reconstruction²⁴.Subacromial balloon²⁵.

Rationale

There remains a paucity of literature comparing tendon transfers with alternatives. However, when considering a tendon transfer, certain principles are critical in order to achieve an optimal outcome:The recipient and transferred tendons must have similar musculotendinous excursion.The recipient and transferred tendons should have similar lines of pull.One tendon (the transferred) should be designed to replace 1 function (of the recipient).The function of the transferred tendon and muscle should be expendable without substantial donor site morbidity.The strength of the transferred muscle must be at least grade 4.When deciding between the LT and LD transfer, certain considerations should be taken into account. The LD transfer has a proven history of successfully treating massive irreparable posterosuperior rotator cuff tears in studies with long-term follow-up^1-6. Alternatively, although the LT transfer has only recently gained popularity, it has the advantage of "in-phase" muscle function, since the trapezius naturally contracts during shoulder external rotation. Furthermore, its line of pull almost completely mimics the infraspinatus.