Fatty infiltration of the supraspinatus: a reliability study

Assessment of the Rotator Cuff Muscles: State-of-the-Art MRI and Clinical Implications

Rotator cuff (RC) tears are a common cause of shoulder pain and, depending on the tear pattern, can substantially limit daily activities and affect quality of life. After a tendon tear, the RC muscle undergoes degenerative changes, including fatty degeneration and volume atrophy. The extent of fatty muscle degeneration has been associated with poorer functional and surgical outcomes after RC reconstruction, and the evaluation of the RC muscles is one of the most important factors for deciding whether to perform an RC repair. A variety of qualitative and quantitative methods are available to assess RC fatty muscle degeneration and volume atrophy based on MRI. This review provides a detailed overview of the RC muscle assessment, including qualitative measurements to assess the RC muscles, such as Goutallier grading, tangent sign, and fish backbone sign. Another focus is state-of-the-art quantitative MRI techniques, including chemical shift-based techniques such as single-voxel MR spectroscopy, multipoint water-fat separation, and MR relaxometry. Furthermore, the clinical relevance of qualitative and quantitative intramuscular fat assessment is addressed, and its potential importance for treatment planning and patient outcomes is discussed.

Muscle Health & Fatty Infiltration with Advanced Rotator Cuff Pathology

PURPOSE OF REVIEW

Fatty infiltration (FI) of the rotator cuff is a critical determinant of clinical outcomes following rotator cuff injuries and repairs. This review examines the natural history, pathophysiology, imaging evaluation, and treatment strategies for FI, highlighting recent insights into its cellular mechanisms and emerging therapeutic approaches.

RECENT FINDINGS

Animal models demonstrate that FI begins shortly after tendon injury, progresses with muscle retraction and denervation, and is largely irreversible despite repair. Key cellular drivers include fibroadipogenic progenitor cells (FAPs), influenced by mechanical loading and inflammatory signaling pathways. Clinical studies show that FI is associated with advanced age, female sex, and full-thickness tears. Higher degrees of preoperative FI correlate with poorer functional outcomes and increased re-tear rates. Novel therapeutic targets, including pathways regulating FAP activity, TGF-β, and cell-based therapies, show promise in preclinical studies. Emerging strategies such as leukocyte-poor platelet-rich plasma (PRP) may mitigate FI progression in clinical settings. Fatty infiltration remains a significant barrier to successful rotator cuff repair and functional recovery. While surgical repair may slow FI progression, it is not consistently effective in reversing established muscle degeneration. Improved understanding of the molecular mechanisms driving FI has identified potential therapeutic targets, but their clinical applicability requires further validation. Future advances in regenerative medicine, including cell-based therapies and modulation of fibroadipogenic progenitors, offer hope for mitigating FI and improving long-term outcomes.

Qualitative analysis of the supraspinatus muscle fatty infiltration on MRI: correlation of the tangent sign with Goutallier grade at the Y view and medial scapular border in large retracted rotator cuff tears

BACKGROUND

Surgically repairing rotator cuff tears with a higher extent of fatty infiltration (FI) is controversial. Current evidence supports performing rotator cuff repair in patients exhibiting Goutallier stage 3-4 FI. However, the presence of retraction complicates accurate assessment using the Goutallier Classification, particularly on the lateral Y-view. A shift toward classifying FI in more medial regions may enhance the precision of tissue quality quantification. The objective of this study was to analyze the uniformity of FI within the entire supraspinatus muscle using the Goutallier Classification across 3 scapular Y-view sections and to examine the association between Goutallier grade, tangent sign, and modified Patte stage.

METHODS

A retrospective evaluation was conducted on preoperative magnetic resonance imaging scans from a consecutive series of 97 patients who had previously undergone arthroscopic rotator cuff repairs. Three supraspinatus sections on the magnetic resonance imaging sagittal plane were identified: the lateral Y-view (section 1), a medial section at the suprascapular notch anatomical landmark (section 2), and a section 3 cm medial from the suprascapular notch Medial Scapular Body (section 3). Goutallier grade, tangent sign, and modified Patte stage were used to evaluate FI, muscle atrophy, and tendon retraction, respectively.

RESULTS

Section 1 had the highest Goutallier grade, while section 3 had the lowest. Intraobserver rest retest reliability analysis showed excellent consistency in all sections with section 2 (intraclass correlation coefficient [ICC] = 0.920, 95% confidence interval [CI]), section 2 (ICC = 0.917, 95% CI), and section 3 (ICC = 0.923, 95% CI) for Goutallier grade. Interobserver reliability analysis also revealed excellent consistency in section 1 (ICC = 0.951, 95% CI), section 2 (ICC = 0.949, 95% CI), and section 3 (ICC = 0.922, 95% CI) for Goutallier grade. A strong correlation was observed between Goutallier grade and modified Patte stage (τb = 0.43-0.56, P = .001), and between Goutallier grade and tangent sign (τb = 0.43-0.54, P = .001) across all sections.

CONCLUSION

The severity of FI within the supraspinatus muscle belly is inconsistent, with the lateral portion being the most severe and the medial portion the least severe. Goutallier grade demonstrates a strong correlation with tangent sign and modified Patte stage. This suggests that tendon retraction results in a potential overestimation in the amount of FI defining some tears unjustly irreparable when measuring at the traditionally described lateral Y-view position compared with 3 cm medial.

A visual marker for early atrophy of the supraspinatus muscle on conventional MRI: introduction of the blackbird sign

OBJECTIVES

The aim of this study was to introduce the blackbird sign as a fast, qualitative measure of early supraspinatus (SSP) muscle atrophy and to correlate the sign with quantitatively assessed muscle volume and intramuscular fat fraction (FF) in patients with full-thickness SSP tears.

MATERIALS AND METHODS

The blackbird sign describes the asymmetric pattern of early SSP atrophy: on sagittal MR images, the supero-posterior contour of the muscle becomes concave, resembling the shape of a blackbird. MRIs of patients with full-thickness SSP tears were retrospectively reviewed for the presence of the blackbird and tangent signs. Patients were then divided into group 1: negative tangent sign and negative blackbird sign (n = 67), group 2: negative tangent sign and positive blackbird sign (n = 31), and group 3: positive tangent sign (n = 32). A 2-point Dixon sequence was acquired in all patients from which quantitative FF and muscle volumes were calculated.

RESULTS

In total 130 patients (mean age 67 ± 11 years) were included. Mean SSP volume was significantly smaller in group 3 (15.8 ± 8.1 cm3) compared to group 2 (23.9 ± 7.0 cm3, p = 0.01) and group 1 (29.7 ± 9.1 cm3, p < 0.01). Significantly lower muscle volumes were also found in group 2 compared to group 1 (p = 0.02), confirming that the blackbird sign is able to identify early SSP atrophy. Mean FF in the SSP was significantly higher in group 3 (18.5 ± 4.4%) compared to group 2 (10.9 ± 4.7%, p < 0.01) and group 1 (6.1 ± 2.6%, p < 0.01).

CONCLUSION

Visual assessment of early muscle atrophy of the SSP is feasible and reproducible using the blackbird sign, allowing the diagnosis of early SSP atrophy.

CLINICAL RELEVANCE STATEMENT

In routine clinical practice, the blackbird sign may be a useful tool for assessing early muscle degeneration before the risk of postoperative rotator cuff re-tears increases with progressive muscle atrophy and fatty infiltration.

KEY POINTS

Quantitative measurements of rotator cuff injuries require time, limiting clinical practicality. The proposed blackbird sign is able to identify early SSP atrophy. Reader agreement for the blackbird sign was substantial, demonstrating reproducibility and ease of implementation in the clinical routine.

Are glenoid retroversion, humeral subluxation, and Walch classification associated with a muscle imbalance?

BACKGROUND

The etiology of humeral posterior subluxation remains unknown, and it has been hypothesized that horizontal muscle imbalance could cause this condition. The objective of this study was to compare the ratio of anterior-to-posterior rotator cuff and deltoid muscle volume as a function of humeral subluxation and glenoid morphology when analyzed as a continuous variable in arthritic shoulders.

METHODS

In total, 333 computed tomography scans of shoulders (273 arthritic shoulders and 60 healthy controls) were included in this study and were segmented automatically. For each muscle, the volume of muscle fibers without intramuscular fat was measured. The ratio between the volume of the subscapularis and the volume of the infraspinatus plus teres minor (AP ratio) and the ratio between the anterior and posterior deltoids (APdeltoid) were calculated. Statistical analyses were performed to determine whether a correlation could be found between these ratios and glenoid version, humeral subluxation, and/or glenoid type per the Walch classification.

RESULTS

Within the arthritic cohort, no statistically significant difference in the AP ratio was found between type A glenoids (1.09 ± 0.22) and type B glenoids (1.03 ± 0.16, P = .09), type D glenoids (1.12 ± 0.27, P = .77), or type C glenoids (1.10 ± 0.19, P > .999). No correlation was found between the AP ratio and glenoid version (ρ = -0.0360, P = .55) or humeral subluxation (ρ = 0.076, P = .21). The APdeltoid ratio of type A glenoids (0.48 ± 0.15) was significantly greater than that of type B glenoids (0.35 ± 0.16, P < .01) and type C glenoids (0.21 ± 0.10, P < .01) but was not significantly different from that of type D glenoids (0.64 ± 0.34, P > .999). When evaluating both healthy control and arthritic shoulders, moderate correlations were found between the APdeltoid ratio and both glenoid version (ρ = 0.55, P < .01) and humeral subluxation (ρ = -0.61, P < .01).

CONCLUSION

This in vitro study supports the use of software for fully automated 3-dimensional reconstruction of the 4 rotator cuff muscles and the deltoid. Compared with previous 2-dimensional computed tomography scan studies, our study did not find any correlation between the anteroposterior muscle volume ratio and glenoid parameters in arthritic shoulders. However, once deformity occurred, the observed APdeltoid ratio was lower with type B and C glenoids. These findings suggest that rotator cuff muscle imbalance may not be the precipitating etiology for the posterior humeral subluxation and secondary posterior glenoid erosion characteristic of Walch type B glenoids.

Traumatic and Atraumatic Rotator Cuff Tears Have the Same Rates of Healing

Background

To examine whether traumatic rotator cuff repairs (RCRs) differ in postoperative rotator cuff tendon integrity and functional outcomes from degenerative RCRs.

Methods

RCRs performed by a single surgeon were retrospectively identified. The inclusion criteria were repairable Goutallier grades 0 to 2 full-thickness rotator cuff tears. Demographic and clinical data as well as radiological results were compared. A multivariate logistic regression of the of patient acceptable symptom state for American Shoulder and Elbow Surgeons (ASES) score was performed to evaluate whether the origin of tear led to a different relative risk (RR) independently from tear and surgical characteristics.

Results

A total of 616 consecutive shoulders (304 traumatic and 312 degenerative) were finally included. Traumatic ruptures presented a greater distribution of male (72% vs 51%, P < .001) and younger patients (53 vs 57 years, P < .001), as well as earlier onset of symptoms (3 vs 15 months, P < .001), reduced range of motion in preoperative assessment for forward elevation (130° vs 150°, P < .001), and slightly greater preoperative ASES (46.5 ± 19.7 vs 50.0 ± 18.0, P = .022) and Constant (47.0 ± 20.2 vs 52.0 ± 18.9, P = .001) scores. Degenerative tears presented a lower proportion of grade 3 tendon coronal retraction (11% vs 18%, P = .031). Postoperative tendon integrity at 6 months was comparable for both groups, predominantly Sugaya types 1 and 2 (91% traumatic; 92% degenerative, P = .371). Both groups exhibited favorable outcomes in range of motion and postoperative functional scores at last follow-up. The multivariate regression confirmed that the tear origin was not significantly associated with patient acceptable symptom state achievement (P = .201) but rather with greater preoperative ASES score (RR, 1.01), men (RR, 1.16) and workers' compensation (RR, 0.65) (P < .05).

Conclusions

Traumatic cases were frequent, involved younger patients, more frequently affected the anterior rotator cuff, and were associated with more severe tendon retraction. Traumatic and degenerative RCRs lead to comparable clinical and radiologic results.

Level of Evidence

Level III, retrospective comparative study.

Objective analysis of partial three-dimensional rotator cuff muscle volume and fat infiltration across ages and sex from clinical MRI scans

Objective analysis of rotator cuff (RC) atrophy and fatty infiltration (FI) from clinical MRI is limited by qualitative measures and variation in scapular coverage. The goals of this study were to: develop/evaluate a method to quantify RC muscle size, atrophy, and FI from clinical MRIs (with typical lateral only coverage) and then quantify the effects of age and sex on RC muscle. To develop the method, 47 full scapula coverage CTs with matching clinical MRIs were used to: correct for variation in scan capture, and ensure impactful information of the RC is measured. Utilizing this methodology and automated artificial intelligence, 170 healthy clinical shoulder MRIs of varying age and sex were segmented, and each RC muscle's size, relative contribution, and FI as a function of scapula location were quantified. A two-way ANOVA was used to examine the effect of age and sex on RC musculature. The analysis revealed significant (p < 0.05): decreases in size of the supraspinatus, teres minor, and subscapularis with age; decreased supraspinatus and increased infraspinatus relative contribution with age; and increased FI in the infraspinatus with age and in females. This study demonstrated that clinically obtained MRIs can be utilized for automatic 3D analysis of the RC. This method is not susceptible to coverage variation or patient size. Application of methodology in a healthy population revealed differences in RC musculature across ages and FI level between sexes. This large database can be used to reference expected muscle characteristics as a function of scapula location and could eventually be used in conjunction with the proposed methodology for analysis in patient populations.

REASSESSMENT OF FATTY INFILTRATION BY MAGNETIC RESONANCE TEN YEARS AFTER ROTATOR CUFF INJURY REPAIR

Quantitative assessments of rotator cuff muscle changes after successful tendon repair are scarce. On the other hand, semiquantitative and subjective assessments are more abundant, but their findings are controversial. One hypothesis about this divergence is that there is an immediate decrease in the proportion of fatty infiltration after surgical repair.

Objective

Reassess fatty infiltration and muscle trophism of the rotator cuff after ten years of repair.

Methods

Prospective comparison study. A total of 10 patients diagnosed with rotator cuff injury underwent repair of the lesion, and MRI of the affected shoulder was performed in the preoperative, immediate postoperative, and late postoperative periods (ten years). A comparative study was performed at every moment.

Results

At 5% significance level, the mean of the immediate postoperative period was higher for the variable trophism and true muscle percentage. Fatty infiltration showed no difference in the three periods observed.

Conclusion

Fatty infiltration does not change in the three periods evaluated and muscle trophism is greater in the immediate postoperative period. After ten years of rotator cuff repair, muscle trophism and fatty infiltration remain with statistically significantly equal results when compared to the preoperative period. Level of Evidence II, Prospective Comparison Study.

Three-dimensional quantitative measurements of atrophy and fat infiltration in sub-regions of the supraspinatus muscle show heterogeneous distributions: a cadaveric study

INTRODUCTION

Rotator cuff tears are common in the older population. Atrophy and fat infiltration develop un-evenly in torn supraspinatus (SSP) muscles leading to pre- and post-surgical complications. The purpose of the current study was twofold: first, to implement a volumetric and quantitative magnetic resonance imaging (MRI) approach to quantify the degree of muscle atrophy and fat infiltration within the SSP muscle and its four sub-regions (AS, PS, AD, and PD); second to compare 3-D MRI outcomes to the standard 2-D assessment and investigate their relationship with tear size.

MATERIALS AND METHODS

Fifteen cadaveric shoulders were obtained and MRI performed. Quantitative 3-D outcomes included SSP muscle volume, fossa volume, fat-free muscle volume, and fat fraction for the whole SSP muscle and its four sub-regions. 2-D and qualitative measurements included tear size, 2-D fat infiltration using the Goutallier classification, tangent sign, and occupation ratio.

RESULTS

Linear regression outcomes with tear size were not significant for both cross-sectional area (r = - 0.494, p = 0.061) and occupation ratio (r = - 0.011, p = 0.969). Tear size negatively correlated with fat-free muscle volume for both AS and PS sub-regions (AS: r = - 0.78, p < 0.001; PS: r = - 0.68, p = 0.005, respectively) while showing no significant correlation with fat fraction outcomes. AD and PD sub-regions positively correlated with tear size and fat fraction outcomes (AD: r = 0.70, p = 0.017; PD: r = 0.52, p = 0.045, respectively), while no significant correlation was observed between tear size and fat-free muscle volumes.

CONCLUSION

Quantitative 3-D volumetric assessment of muscle degeneration resulted in better outcomes compared to the standard 2-D evaluation. The superficial supraspinatus muscle sub-regions primarily presented muscle atrophy, while the deep sub-regions were mainly affected by fat infiltration. 3-D assessments could be used pre-surgically to determine the best course of treatment and to estimate the muscles' regenerative capacity and function.

Validation of a 3D CT imaging method for quantifying implant migration following anatomic total shoulder arthroplasty

Glenoid component loosening remains a common complication following anatomic total shoulder arthroplasty (TSA); however, plain radiographs are unable to accurately detect early implant migration. The purpose of this study was to validate the accuracy of a method of postoperative, three-dimensional (3D) computed tomography (CT) imaging with metal artifact reduction (MAR) to detect glenoid component migration following anatomic TSA. Tantalum bead markers were inserted into polyethylene glenoid components for implant detection on 3D CT. In-vitro validation was performed using a glenoid component placed into a scapula sawbone and incrementally translated and rotated, with MAR 3D CT acquired at each test position. Accuracy was evaluated by root mean square error (RMSE). In-vivo validation was performed on six patients who underwent anatomic TSA, with two postoperative CT scans acquired in each patient and marker-based radiostereometric analysis (RSA) performed on the same days. Glenoid component migration was calculated relative to a scapular coordinate system for both MAR 3D CT and RSA. Accuracy was evaluated by RMSE and paired Student's t-tests. The largest RMSE on in-vitro testing was 0.24 mm in translation and 0.11° in rotation, and on in-vivo testing was 0.47 mm in translation and 1.04° in rotation. There were no significant differences between MAR 3D CT and RSA measurement methods. MAR 3D CT imaging is capable of quantifying glenoid component migration with a high level of accuracy. MAR 3D CT imaging is advantageous over RSA because it is readily available clinically and can also be used to evaluate the implant-bone interface.

Achilles Tendon–Bone Block Allograft for Massive Rotator Cuff Tears With Bony Deficiency of the Greater Tuberosity: A Minimum 2-Year Follow-up Study

Background:

Massive rotator cuff tears associated with greater tuberosity bone loss are challenging to treat. Repairing the rotator cuff without addressing the greater tuberosity deficiency may result in poorer clinical outcomes.

Hypothesis:

Utilizing an Achilles tendon–bone block allograft to address both the massive rotator cuff tear and greater tuberosity bone loss concurrently can result in improved clinical outcomes.

Study Design:

Case series; Level of evidence, 4.

Methods:

The authors performed a retrospective study of patients treated between January 2011 and December 2018 with Achilles tendon–bone block allograft for massive rotator cuff tears associated with greater tuberosity bone loss. The inclusion criteria were massive rotator cuff tear and bony deficiency of the greater tuberosity; patients with a history of bony metabolism disease, connective tissue disease, and previous surgery to the wrist or elbow of the affected limb were excluded. Range of motion, visual analog scale for pain, Constant score, and Single Numeric Assessment Evaluation score were assessed preoperatively and at a minimum of 2 years postoperatively. Radiographs and ultrasound images were evaluated to assess allograft union and rotator cuff integrity.

Results:

Five patients (3 male and 2 female; mean age, 54.0 ± 12.2 years) were included in the study. The mean follow-up was 80.6 ± 33.7 months. Preoperative to postoperative values improved significantly on the visual analog scale (from 45.8 ± 25.5 to 14.5 ± 14.1; P = .04), Constant score (from 36.8 ± 7.9 to 73.5 ± 3.1; P < .001), and Single Numeric Assessment Evaluation score (from 42.5 ± 26.3 to 82.5 ± 10.4; P = .04). Forward flexion improved significantly from 53° ± 47° to 149° ± 17° (P = .03). Four of the 5 patients achieved bony union. One patient required removal of symptomatic hardware at 6 months postoperatively, and 1 patient required revision surgery at 1 year postoperatively because of progressive osteonecrosis of the humeral head.

Conclusion:

In patients with massive rotator cuff tears and a greater tuberosity bony deficiency, utilizing an Achilles tendon–bone block allograft to restore the bony defect and reinforce the rotator cuff repair was safe and effective. At a minimum of 2 years postoperatively, most patients demonstrated improved clinical outcomes, tendon healing, and graft incorporation.

Three-dimensional muscle loss assessment: a novel computed tomography-based quantitative method to evaluate rotator cuff muscle fatty infiltration

BACKGROUND

Rotator cuff fatty infiltration (FI) is one of the most important parameters to predict the outcome of certain shoulder conditions. The primary objective of this study was to define a new computed tomography (CT)-based quantitative 3-dimensional (3D) measure of muscle loss (3DML) based on the rationale of the 2-dimensional (2D) qualitative Goutallier score. The secondary objective of this study was to compare this new measurement method to traditional 2D qualitative assessment of FI according to Goutallier et al and to a 3D quantitative measurement of fatty infiltration (3DFI).

MATERIALS AND METHODS

102 CT scans from healthy shoulders (46) and shoulders with cuff tear arthropathy (21), irreparable rotator cuff tears (18), and primary osteoarthritis (17) were analyzed by 3 experienced shoulder surgeons for subjective grading of fatty infiltration according to Goutallier, and their rotator cuff muscles were manually segmented. Quantitative 3D measurements of fatty infiltration (3DFI) were completed. The volume of muscle fibers without intramuscular fat was then calculated for each rotator cuff muscle and normalized to the patient's scapular volume to account for the effect of body size (NV_fibers). 3D muscle mass (3DMM) was calculated by dividing the NV_fibers value of a given muscle by the mean expected volume in healthy shoulders. 3D muscle loss (3DML) was defined as 1 - (3DMM). The correlation between Goutallier grading, 3DFI, and 3DML was compared using a Spearman rank correlation.

RESULTS

Interobserver reliability for the traditional 2D Goutallier grading was moderate for the infraspinatus (ISP, 0.42) and fair for the supraspinatus (SSP, 0.38), subscapularis (SSC, 0.27) and teres minor (TM, 0.27). 2D Goutallier grading was found to be significantly and highly correlated with 3DFI (SSP, 0.79; ISP, 0.83; SSC, 0.69; TM, 0.45) and 3DML (SSP, 0.87; ISP, 0.85; SSC, 0.69; TM, 0.46) for all 4 rotator cuff muscles (P < .0001). This correlation was significantly higher for 3DML than for the 3DFI for SSP only (P = .01). The mean values of 3DFI and 3DML were 0.9% and 5.3% for Goutallier 0, 2.9% and 25.6% for Goutallier 1, 11.4% and 49.5% for Goutallier 2, 20.7% and 59.7% for Goutallier 3, and 29.3% and 70.2% for Goutallier 4, respectively.

CONCLUSION

The Goutallier score has been helping surgeons by using 2D CT scan slices. However, this grading is associated with suboptimal interobserver agreement. The new measures we propose provide a more consistent assessment that correlates well with Goutallier's principles. As 3DML measurements incorporate atrophy and fatty infiltration, they could become a very reliable index for assessing shoulder muscle function. Future algorithms capable of automatically calculating the 3DML of the cuff could help in the decision process for cuff repair and the choice of anatomic or reverse shoulder arthroplasty.

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.

Irreparable Large to Massive Rotator Cuff Tears With Low-Grade Fatty Degeneration of the Infraspinatus Tendon: Minimum 7-Year Follow-up of Fascia Autograft Patch Procedure and Partial Repair

BACKGROUND

In shoulders with irreparable massive rotator cuff tears (RCTs) with high-grade fatty degeneration (Goutallier stage 3 or 4) of the supraspinatus tendon and low-grade fatty degeneration (Goutallier stage 1 or 2) of the infraspinatus tendon (ISP), arthroscopic patch grafting (PG) has been reported as superior to partial repair (PR) regarding the ISP retear rate at short-term to midterm follow-up. However, the longer term outcomes are unclear.

PURPOSE

To compare clinical and structural outcomes in the PG and PR groups at a minimum of 7 years postoperatively.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We evaluated 24 patients in the PG group and 24 patients in the PR group. We primarily used the Constant score for clinical outcomes and performed magnetic resonance imaging for structural outcomes in the PG and PR groups. The risk factors for a retear of the ISP were identified by univariate and multivariate (forward stepwise selection method) logistic regression analyses. We primarily compared values at midterm follow-up (<4 years) with values at the final follow-up (minimum 7 years) for each patient.

RESULTS

The mean midterm and final follow-up times for the PG group were 41.0 and 95.1 months, respectively, compared with 35.7 and 99.3 months, respectively, for the PR group. We found significant differences for the midterm and final follow-up Constant total scores in the PG and PR groups (midterm follow-up: 79.1 vs 69.9, respectively [P = .001]; final follow-up: 76.0 vs 65.3, respectively [P = .006]) and in the Constant strength scores (midterm follow-up: 14.6 vs 8.5, respectively [P < .001]; final follow-up: 13.1 vs 8.3, respectively [P = .001]). Treatment group (PR) was a significant predictor of an ISP retear in the logistic regression analysis (odds ratio, 3.545; P = .043).

CONCLUSION

Patients with low-grade massive RCTs treated with PG or PR improved significantly in terms of clinical outcomes at the midterm and final follow-up time points. However, Constant scores were significantly better in the PG group at the final follow-up.

CT-based volumetric assessment of rotator cuff muscle in shoulder arthroplasty preoperative planning

Aims

The aim of this study was to describe a quantitative 3D CT method to measure rotator cuff muscle volume, atrophy, and balance in healthy controls and in three pathological shoulder cohorts.

Methods

In all, 102 CT scans were included in the analysis: 46 healthy, 21 cuff tear arthropathy (CTA), 18 irreparable rotator cuff tear (IRCT), and 17 primary osteoarthritis (OA). The four rotator cuff muscles were manually segmented and their volume, including intramuscular fat, was calculated. The normalized volume (NV) of each muscle was calculated by dividing muscle volume to the patient’s scapular bone volume. Muscle volume and percentage of muscle atrophy were compared between muscles and between cohorts.

Results

Rotator cuff muscle volume was significantly decreased in patients with OA, CTA, and IRCT compared to healthy patients (p < 0.0001). Atrophy was comparable for all muscles between CTA, IRCT, and OA patients, except for the supraspinatus, which was significantly more atrophied in CTA and IRCT (p = 0.002). In healthy shoulders, the anterior cuff represented 45% of the entire cuff, while the posterior cuff represented 40%. A similar partition between anterior and posterior cuff was also found in both CTA and IRCT patients. However, in OA patients, the relative volume of the anterior (42%) and posterior cuff (45%) were similar.

Conclusion

This study shows that rotator cuff muscle volume is significantly decreased in patients with OA, CTA, or IRCT compared to healthy patients, but that only minimal differences can be observed between the different pathological groups. This suggests that the influence of rotator cuff muscle volume and atrophy (including intramuscular fat) as an independent factor of outcome may be overestimated.

Cite this article: Bone Jt Open 2021;2(7):552–561.

MARS MRI assessment of fatty degeneration of the gluteal muscles in patients with THA: reliability and accuracy of commonly used classification systems

INTRODUCTION

Fatty degeneration of the gluteal muscles on metal artefact reduction sequence (MARS) MRI has been shown to correlate with poor functional outcomes, particularly in patients with total hip arthroplasty (THA). Standardized, reliable classification systems that permit assessment of fatty gluteal infiltration are needed for clinical decision making. This study aimed to compare the reproducibility and accuracy of commonly used MRI classification systems for fatty gluteal atrophy in THA patients.

METHODS

MARS magnetic resonance images of 82 patients with unilateral THA were analysed by three independent trained observers. The readers evaluated fatty degeneration of the gluteus minimus, gluteus medius, and gluteus maximus according to 3 widely used classification systems: Goutallier, Quartile, and Bal and Lowe. Interobserver and intraobserver repeatability were determined using the weighted Kappa test. Quantitative evaluation of the proportion of intramuscular fat based on MR signal intensities was obtained and represented the gold standard.

RESULTS

Mean interobserver agreement for the Quartile classification system (0.93) was higher compared with Goutallier classification system (0.87) and the Bal and Lowe classification system (0.83; range 0.79-0.88; p = 0.04). Intraobserver repeatability was significantly higher for the Quartile classification system (weighted kappa 0.91, 0.89, 0.85) compared with the Bal and Lowe classification system (weighted kappa 0.83, 0.77, 0.75; p < 0.01) and Goutallier classification system (weighted kappa 0.83, 0.77, 0.75; p = 0.04). Agreement with the gold standard measurements was significantly higher in the Quartile classification system (0.88, 0.84, 0.81) compared with the Goutallier classification system (0.80, 0.77, 0.78; p = 0.02) and Bal and Lowe classification system (0.76, 0.74, 0.73; p < 0.01).

DISCUSSION

This study directly compared three clinically used MRI classification systems for fatty gluteal muscle atrophy in THA patients. Our findings demonstrate that although all three classification systems demonstrate good reproducibility and accuracy, the Quartile classification system is superior to the others in terms of intraobserver reliability and accuracy to quantify fatty gluteal degeneration in THA patients.

Relationship between fatty infiltration and gene expression in patients with medium rotator cuff tear

BACKGROUND

Fatty infiltration (FI) is a key prognostic factor that affects outcomes after rotator cuff repair and is radiologically evaluated using the Goutallier classification. The purpose of this study was to assess alterations in gene and protein expression according to the Goutallier classification in the supraspinatus muscle and any relationships among various gene expression profiles.

METHODS

Twenty-four samples of the supraspinatus muscle from 12 patients with a high FI grade (grade 3 or 4) and 12 patients with a low FI grade (grade 1 or 2) with medium-sized tears were acquired during arthroscopic surgery. Alterations in the expression of genes and proteins associated with adipogenesis, fibrosis, inflammation, and muscle atrophy were compared between the high- and low-FI groups using reverse-transcription quantitative polymerase chain reaction, Western blotting, and immunohistochemistry.

RESULTS

mRNA expression of not only the adipogenic genes (peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α; P < .001 and P = .020) but also the fibrosis-related gene (α-smooth muscle actin; P < .001), inflammation-related genes (interleukin [IL]-1β and tumor necrosis factor α; P = .041 and P = .039), and muscle atrophy-related genes (atrogin 1 and myostatin; P = .006 and P < .001) was higher in the high-FI group compared with that in the low-FI group. In addition, adipogenic gene expression was significantly correlated with the expression of other categories of genes (all P < .05, except atrogin 1). A correlation of gene and protein expression was observed for IL-1β (P = .027) and myostatin (P = .029).

CONCLUSIONS

The radiologic grading of FI was associated with the expression of various genes, including adipogenic, fibrotic, inflammatory, and atrophy-related genes, and these genes were closely correlated with each other in terms of expression. This information could be helpful in patient counseling.

Machine Learning Can Predict Level of Improvement in Shoulder Arthroplasty

The ability to accurately predict postoperative outcomes is of considerable interest in the field of orthopaedic surgery. Machine learning has been used as a form of predictive modeling in multiple health-care settings. The purpose of the current study was to determine whether machine learning algorithms using preoperative data can predict improvement in American Shoulder and Elbow Surgeons (ASES) scores for patients with glenohumeral osteoarthritis (OA) at a minimum of 2 years after shoulder arthroplasty.

METHODS

This was a retrospective cohort study that included 472 patients (472 shoulders) diagnosed with primary glenohumeral OA (mean age, 68 years; 56% male) treated with shoulder arthroplasty (431 anatomic total shoulder arthroplasty and 41 reverse total shoulder arthroplasty). Preoperative computed tomography (CT) scans were used to classify patients on the basis of glenoid and rotator cuff morphology. Preoperative and final postoperative ASES scores were used to assess the level of improvement. Patients were separated into 3 improvement ranges of approximately equal size. Machine learning methods that related patterns of these variables to outcome ranges were employed. Three modeling approaches were compared: a model with the use of all baseline variables (Model 1), a model omitting morphological variables (Model 2), and a model omitting ASES variables (Model 3).

RESULTS

Improvement ranges of ≤28 points (class A), 29 to 55 points (class B), and >55 points (class C) were established. Using all follow-up time intervals, Model 1 gave the most accurate predictions, with probability values of 0.94, 0.95, and 0.94 for classes A, B, and C, respectively. This was followed by Model 2 (0.93, 0.80, and 0.73) and Model 3 (0.77, 0.72, and 0.71).

CONCLUSIONS

Machine learning can accurately predict the level of improvement after shoulder arthroplasty for glenohumeral OA. This may allow physicians to improve patient satisfaction by better managing expectations. These predictions were most accurate when latent variables were combined with morphological variables, suggesting that both patients' perceptions and structural pathology are critical to optimizing outcomes in shoulder arthroplasty.

LEVEL OF EVIDENCE

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

Rotator cuff tear degeneration and the role of fibro-adipogenic progenitors

The high prevalence of rotator cuff tears poses challenges to individual patients and the healthcare system at large. This orthopedic injury is complicated further by high rates of retear after surgical repair. Outcomes following repair are highly dependent upon the quality of the injured rotator cuff muscles, and it is, therefore, crucial that the pathophysiology of rotator cuff degeneration continues to be explored. Fibro-adipogenic progenitors, a major population of resident muscle stem cells, have emerged as the main source of intramuscular fibrosis and fatty infiltration, both of which are key features of rotator cuff muscle degeneration. Improvements to rotator cuff repair outcomes will likely require addressing the muscle pathology produced by these cells. The aim of this review is to summarize the current rotator cuff degeneration assessment tools, the effects of poor muscle quality on patient outcomes, the role of fibro-adipogenic progenitors in mediating muscle pathology, and how these cells could be leveraged for potential therapeutics to augment current rotator cuff surgical and rehabilitative strategies.

Deep learning for the rapid automatic quantification and characterization of rotator cuff muscle degeneration from shoulder CT datasets

Objectives

This study aimed at developing a convolutional neural network (CNN) able to automatically quantify and characterize the level of degeneration of rotator cuff (RC) muscles from shoulder CT images including muscle atrophy and fatty infiltration.

Methods

One hundred three shoulder CT scans from 95 patients with primary glenohumeral osteoarthritis undergoing anatomical total shoulder arthroplasty were retrospectively retrieved. Three independent radiologists manually segmented the premorbid boundaries of all four RC muscles on standardized sagittal-oblique CT sections. This premorbid muscle segmentation was further automatically predicted using a CNN. Automatically predicted premorbid segmentations were then used to quantify the ratio of muscle atrophy, fatty infiltration, secondary bone formation, and overall muscle degeneration. These muscle parameters were compared with measures obtained manually by human raters.

Results

Average Dice similarity coefficients for muscle segmentations obtained automatically with the CNN (88% ± 9%) and manually by human raters (89% ± 6%) were comparable. No significant differences were observed for the subscapularis, supraspinatus, and teres minor muscles (p > 0.120), whereas Dice coefficients of the automatic segmentation were significantly higher for the infraspinatus (p < 0.012). The automatic approach was able to provide good–very good estimates of muscle atrophy (R² = 0.87), fatty infiltration (R² = 0.91), and overall muscle degeneration (R² = 0.91). However, CNN-derived segmentations showed a higher variability in quantifying secondary bone formation (R² = 0.61) than human raters (R² = 0.87).

Conclusions

Deep learning provides a rapid and reliable automatic quantification of RC muscle atrophy, fatty infiltration, and overall muscle degeneration directly from preoperative shoulder CT scans of osteoarthritic patients, with an accuracy comparable with that of human raters.

Key Points

• Deep learning can not only segment RC muscles currently available in CT images but also learn their pre-existing locations and shapes from invariant anatomical structures visible on CT sections.

• Our automatic method is able to provide a rapid and reliable quantification of RC muscle atrophy and fatty infiltration from conventional shoulder CT scans.

• The accuracy of our automatic quantitative technique is comparable with that of human raters.

Efficacy of Imaging Modalities Assessing Fatty Infiltration in Rotator Cuff Tears

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

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.

The effect of obesity on fatty infiltration of the rotator cuff musculature in patients without rotator cuff tears

BACKGROUND

The modified Goutallier classification system describes the fatty infiltration of rotator cuff musculature (RCM) seen on magnetic resonance imaging (MRI) to assist with surgical decision-making for patients with rotator cuff tears (RCT). We describe the relationship between body mass index (BMI) and fatty infiltration in patients without RCT.

METHODS

Twenty-five patients from each of four different BMI ranges (< 25 kg/m²; 25 kg/m² to 30 kg/m²; 30 kg/m² to 35 kg/m²; > 35 kg/m²) were randomly selected from 1088 consecutive shoulder MRI scans (T1 parasagittal series). Four physician-readers evaluated MRI scans and assigned modified Goutallier grades (0 to 4) in each of the four rotator cuff muscles, as well as two adjacent muscles.

RESULTS

Grade distributions varied significantly based on BMI category for infraspinatus (p = 0.001), teres minor (p < 0.001), subscapularis (p = 0.025), teres major (p < 0.001) and deltoid (p < 0.001). Higher grades were evident with a diagnosis of diabetes mellitus in three of six muscles (p < 0.05), hyperlipidaemia in one muscle (p = 0.021) and greater patient age in three muscles (p < 0.05).

CONCLUSIONS

Obese and severely obese patients without RCT have more fatty infiltration seen on MRI. Patient factors (older age and diagnosis of diabetes mellitus) can be predictive of fatty infiltration in RCM. Fatty infiltration of RCM is not solely attributable to the presence of a RCT.

Muscle size and composition in people with articular hip pathology: a systematic review with meta-analysis

OBJECTIVE

To synthesise and evaluate the current evidence investigating muscle size and composition in non-inflammatory articular hip pathology.

METHODS

A systematic review of five electronic databases, using three concepts; articular hip pathology (e.g., osteoarthritis (OA)); hip muscles; and outcomes (e.g., muscle size and adiposity) was undertaken. Studies addressing non-inflammatory or non-traumatic articular hip pain, using measures of muscle size and adiposity were included and appraised for risk of bias. Data was extracted to calculate standardised mean differences (SMD) and pooled where possible for meta-analysis.

RESULTS

Thirteen cross-sectional studies were included; all studies measured muscle size and 5/13 measured adiposity. In OA, there was low to very low quality evidence of no difference in hip muscle size, compared with matched controls. In unilateral OA, there was low to very low quality evidence of smaller size in gluteus minimus (SMD -0.38; 95% confidence interval (CI) -0.74, -0.01), gluteus medius (-0.44; 95% CI: -0.83, -0.05) and gluteus maximus (-0.39; 95% CI: -0.75, -0.02) muscles in the symptomatic limb. Individual studies demonstrated non-uniform changes in muscle size in OA. No significant difference was observed in muscle size in other pathologies or in adiposity for any group.

CONCLUSION

There is some low quality evidence that specific hip muscles are smaller in unilateral hip OA. Variation in the magnitude of differences indicate changes in size are not uniform across all muscles or stage of pathology. Studies in larger cohorts investigating muscle size and composition across the spectrum of articular pathologies are required to clarify these findings.

Geometric modification of the humeral position after total reverse shoulder arthroplasty: what is the optimal lowering of the humerus?

BACKGROUND

The main mechanical effect after reverse shoulder arthroplasty (RSA) is the lowering of the glenohumeral rotation center. The optimal value of the humeral lowering after RSA is still debated. The main objective of our study was to determine the lowering and medialization of the humerus and to correlate these parameters with short-term functional results.

MATERIALS AND METHODS

The study included 70 patients with complete radiographic and clinical data. A multivariate analysis was used to compare the clinical and radiographic outcomes with the humeral lowering.

RESULTS

The mean humeral lowering was 25.4 mm (range, 6-38 mm), and the mean medialization was 9.2 mm (range, 0-20 mm). Humeral lowering significantly influenced active forward elevation and the rate of scapular notching.

DISCUSSION

The best clinical results and the lowest incidence of scapular notching were found after a lowering of more than 24 mm in our series. We recommend humeral lengthening of at least 24 mm after implanting a total reverse shoulder prosthesis.

Peroneal Tendon Tears: We Should Consider Looking at the Muscle Instead

INTRODUCTION

The purpose of this study was to determine whether tears of the peroneus brevis (PB) tendon correlate with increased fatty infiltration of the PB muscle on MRI compared with musculature without clinical evidence of peroneal pathology.

METHODS

Ankle MRI scans of patients with PB tendon tearing (tear group) were compared with those of patients without clinical evidence of peroneal pathology (control group). Two reviewers graded the PB muscle belly according to the Goutallier classification.

RESULTS

Thirty patients were included in each group. The mean Goutallier scores for the tear and control groups were 0.52 (±0.72) and 0.05 (±0.15), respectively (P = 0.0019). The level of interobserver agreement between reviewers was moderate (intraclass correlation coefficient = 0.75; 95% confidence interval, 0.57 to 0.85).

DISCUSSION

Patients with PB tendon tear demonstrate markedly higher grades of fatty degeneration compared with patients without peroneal pathology. The Goutallier classification may become a valuable instrument for assessing the severity of a PB tear.

LEVEL OF EVIDENCE

Level III-diagnostic study.

Computed tomography underestimates rotator cuff pathology in patients with glenohumeral osteoarthritis

BACKGROUND

Computed tomography (CT) is the standard assessment of glenoid morphology before shoulder arthroplasty and is commonly used to evaluate rotator cuff pathology in patients with glenohumeral osteoarthritis (GHOA). Magnetic resonance imaging (MRI) is not routinely used in this setting but has higher sensitivity in diagnosing full-thickness rotator cuff tears (RCT) and is considered the gold standard. The purpose of this study was to determine the sensitivity and specificity of CT in diagnosing full-thickness RCTs and compare the evaluation of fatty infiltration and muscle atrophy on CT vs. MRI in the setting of GHOA.

METHODS

In this retrospective case-controlled study, we identified 49 patients from a prospectively maintained 2-surgeon registry who received preoperative CT and MRI scans for the evaluation of GHOA between 2011 and 2016. Three fellowship-trained shoulder surgeons assessed rotator cuff integrity, fatty infiltration, and muscle atrophy in the CT and MRI scans.

RESULTS

CT sensitivity and specificity were 20% and 95.5%, respectively. Fatty infiltration was significantly lower on CT for the supraspinatus (P = .003), infraspinatus (P < .001), and subscapularis (P = .0182), whereas muscle atrophy was significantly lower on CT for only the supraspinatus (P = .0023).

CONCLUSIONS

Our results suggest that CT underestimates the frequency of full-thickness RCTs and the severity of fatty infiltration and muscle atrophy in the setting of GHOA before total shoulder arthroplasty.

Prediction of the Irreparability of Rotator Cuff Tears

PURPOSE

To determine the influence of preoperative factors on reparability of rotator cuff tears (RCTs) and yield a predictive model for predicting irreparability preoperatively.

METHODS

Among patients with full-thickness RCTs, the reparable group underwent arthroscopic rotator cuff repairs for reparable RCTs whereas the irreparable group underwent alternative surgical procedures for irreparable RCTs. We analyzed age, sex, chronic pseudoparalysis (CPP), mediolateral and anteroposterior tear sizes, acromiohumeral distance (AHD), tangent sign, fatty infiltration (FI) (group 1, Goutallier stage 0 or 1; and group 2, Goutallier stage 2, 3, or 4), and tendon involvement (TI) (type 1, supraspinatus; type 2, supraspinatus and subscapularis; type 3, supraspinatus and infraspinatus; and type 4, all 3 tendons).

RESULTS

The irreparability rate was 12.5%. Between the reparable (663 patients) and irreparable (95 patients) groups, significant differences were found in age (58.8 ± 8.3 years vs 65.6 ± 8.0 years, P < .001); female sex (46.9% vs 63.2%, P = .014); CPP (6.5% vs 36.8%, P < .001); mediolateral tear size (23.7 ± 12.1 mm vs 47.4 ± 9.1 mm, P < .001); anteroposterior tear size (17.9 ± 11.5 mm vs 43.4 ± 16.2 mm, P < .001); AHD (9.0 ± 1.7 mm vs 5.8 ± 1.6 mm, P < .001); tangent sign (2.9% vs 61.1%, P < .001); group 2 FI of the subscapularis (6.9% vs 20.0%, P < .001), supraspinatus (12.1% vs 58.9%, P < .001), infraspinatus (26.8% vs 69.5%, P < .001), and teres minor (4.2% vs 10.5%, P = .008); and type 1, 2, 3, and 4 TI (88.1%, 6.2%, 5.4%, and 0.3%, respectively, vs 29.5%, 21.1%, 28.4%, and 21.1%, respectively; P < .001). Multiple logistic regression analysis showed CPP, mediolateral tear size, AHD, tangent sign, group 2 FI of the supraspinatus, and type 4 TI were significant independent predictors of irreparability, with odds ratios of 3.539 (P = .007), 1.087 (P < .001), 0.624 (P < .001), 6.141 (P < .001), 2.233 (P = .034), and 12.350 (P = .016), respectively. These factors yielded a predictive model for irreparability as follows: Logit P = 1.264 × CPP + 0.084 × Mediolateral tear size - 0.472 × AHD + 0.804 × Group 2 FI of supraspinatus + 1.815 × Tangent sign + 2.514 × Type 4 TI - 3.460.

CONCLUSIONS

The irreparability of RCTs is strongly associated with CPP, mediolateral tear size, AHD, tangent sign, group 2 FI of the supraspinatus, and type 4 TI and can be preoperatively calculated using the predictive equation.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Current concepts in the primary management of irreparable posterosuperior rotator cuff tears without arthritis

Various procedures exist for patients with irreparable posterosuperior rotator cuff tears (IRCT). At present, no single surgical option has demonstrated clinical superiority.There is no panacea for treatment and patients must be aware, in cases of palliative or non-prosthetic options, of an alarming rate of structural failure (around 50%) in the short term.The current review does not support the initial use of complex and expensive techniques in the management of posterosuperior IRCT.Further prospective and comparative studies with large cohort populations and long-term follow-up are necessary to establish effectiveness of expensive or complicated procedures such as superior capsular reconstruction (SCR), subacromial spacers or biological augmentation as reliable and useful alternative treatments for IRCT. Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.180002.

Relationship between neuropathy proximal to the suprascapular nerve and rotator cuff tear in a rodent model

BACKGROUND

Rotator cuff tears are believed to coexist with cervical spine lesions. In cases of preexisting neuropathy, such as cervical spine lesions, fatty degeneration has likely already occurred due to the neuropathy. In these cases, rotator cuff tear is thought to occur easily because of preexisting extensive fatty degeneration and degeneration of the tendons due to neuropathy. This study aimed to evaluate the effects of paralysis due to neuropathy proximal to the suprascapular nerve on the supraspinatus and infraspinatus tendons using a rat model of brachial plexus paralysis.

METHODS

This study included fifteen, 8-week-old Sprague-Dawley rats. The left shoulder was included in the paralysis group and the contralateral shoulder constituted the sham group. Biomechanical testing (evaluated maximum tear force, maximum displacement and Young's modulus) (n = 10) and histological analyses (n = 5) (using the Bonar scale) were performed at 12 weeks postoperatively to confirm the degeneration of the tendon.

RESULTS

The mean maximum tear force was significantly lower in the paralysis group than in the sham group (P = 0.008), indicating that rotator cuff tears occurred with a lower force in the paralysis group. Additionally, the average Young's modulus was significantly greater in the paralysis group than in the sham group (P = 0.003), indicating that the rotator cuff muscle became hard and inflexible in the paralysis group. The Bonar scales of the histological analyses were significantly higher in the paralysis group (total score = 7.04 ± 0.61) than the sham group (total score = 0) (p < 0.0001).

CONCLUSIONS

If neuropathy of proximal to the suprascapular nerve, such as cervical spine or brachial plexus lesion, exists, weakness and degeneration of the rotator cuff tendon and stiffness of the rotator cuff muscle develop. Neuropathy is likely a cause of rotator cuff tears.

Reliability of MR Quantification of Rotator Cuff Muscle Fatty Degeneration Using a 2-point Dixon Technique in Comparison with the Goutallier Classification: Validation Study by Multiple Readers

RATIONALE AND OBJECTIVES

Presurgical assessment of fatty degeneration is important in the management of patients with rotator cuff tears. The Goutallier classification is widely accepted as a qualitative scoring system, although it is highly observer-dependent and has poor reproducibility. The objective of this study was to quantify fatty degeneration of the supraspinatus muscle using a 2-point Dixon technique in patients with rotator cuff tears by multiple readers, and to evaluate the reproducibility compared to Goutallier classification.

MATERIALS AND METHODS

Two hundred patients with rotator cuff tears who underwent magnetic resonance imaging (MRI), including 2-point Dixon sequence at 3.0-T, were selected retrospectively. Qualitative and quantitative analyses of fatty degeneration were performed by two radiologists and three orthopedic surgeons independently. The fat quantification was performed by measuring signal intensity values of in phase (S(In)) and fat image (S(Fat)), and calculating fat fraction as S(Fat)/S(In). The reproducibility of MR quantification was analyzed by the intra- and interclass correlation coefficients and Bland-Altman plots.

RESULTS

The interobserver agreement of the Goutallier classification among five readers was moderate (k = 0.51), whereas the interclass correlation coefficient regarding fat fraction value quantified in 2-point Dixon sequence was excellent (0.893). The mean differences in fat fraction values from the individual segmentation results were from -0.072 to 0.081. Proposed fat fraction grading and Goutallier grading showed similar frequency and distribution in severity of rotator cuff tears.

CONCLUSIONS

Fat quantification in the rotator cuff muscles using a 2-point Dixon technique at 3.0-T MRI is highly reproducible and clinically feasible in comparison to the qualitative evaluation using Goutallier classification.

Intra- and inter-observer agreement in MRI assessment of rotator cuff healing using the Sugaya classification 10years after surgery

BACKGROUND

The long-term outcomes of rotator cuff repair are unclear. Recurrent tears are common, although their reported frequency varies depending on the type and interpretation challenges of the imaging method used. The primary objective of this study was to assess the intra- and inter-observer reproducibility of the MRI assessment of rotator cuff repair using the Sugaya classification 10years after surgery. The secondary objective was to determine whether poor reproducibility, if found, could be improved by using a simplified yet clinically relevant classification.

HYPOTHESIS

Our hypothesis was that reproducibility was limited but could be improved by simplifying the classification.

MATERIAL AND METHOD

In a retrospective study, we assessed intra- and inter-observer agreement in interpreting 49 magnetic resonance imaging (MRI) scans performed 10years after rotator cuff repair. These 49 scans were taken at random among 609 cases that underwent re-evaluation, with imaging, for the 2015 SoFCOT symposium on 10-year and 20-year clinical and anatomical outcomes of rotator cuff repair for full-thickness tears. Each of three observers read each of the 49 scans on two separate occasions. At each reading, they assessed the supra-spinatus tendon according to the Sugaya classification in five types.

RESULTS

Intra-observer agreement for the Sugaya type was substantial (κ=0.64) but inter-observer agreement was only fair (κ=0.39). Agreement improved when the five Sugaya types were collapsed into two categories (1-2-3 and 4-5) (intra-observer κ=0.74 and inter-observer κ=0.68).

CONCLUSION

Using the Sugaya classification to assess post-operative rotator cuff healing was associated with substantial intra-observer and fair inter-observer agreement. A simpler classification into two categories improved agreement while remaining clinically relevant.

LEVEL OF EVIDENCE

II, prospective randomised low-power study.

Quantitative assessment of fatty infiltration and muscle volume of the rotator cuff muscles using 3-dimensional 2-point Dixon magnetic resonance imaging

BACKGROUND

In patients with rotator cuff tears, muscle degeneration is known to be a predictor of irreparable tears and poor outcomes after surgical repair. Fatty infiltration and volume of the whole muscles constituting the rotator cuff were quantitatively assessed using 3-dimensional 2-point Dixon magnetic resonance imaging.

METHODS

Ten shoulders with a partial-thickness tear, 10 shoulders with an isolated supraspinatus tear, and 10 shoulders with a massive tear involving supraspinatus and infraspinatus were compared with 10 control shoulders after matching age and sex. With segmentation of muscle boundaries, the fat fraction value and the volume of the whole rotator cuff muscles were computed. After reliabilities were determined, differences in fat fraction, muscle volume, and fat-free muscle volume were evaluated.

RESULTS

Intra-rater and inter-rater reliabilities were regarded as excellent for fat fraction and muscle volume. Tendon rupture adversely increased the fat fraction value of the respective rotator cuff muscle (P < .002). In the massive tear group, muscle volume was significantly decreased in the infraspinatus (P = .035) and increased in the teres minor (P = .039). With subtraction of fat volume, a significant decrease of fat-free volume of the supraspinatus muscle became apparent with a massive tear (P = .003).

CONCLUSION

Three-dimensional measurement could evaluate fatty infiltration and muscular volume with excellent reliabilities. The present study showed that chronic rupture of the tendon adversely increases the fat fraction of the respective muscle and indicates that the residual capacity of the rotator cuff muscles might be overestimated in patients with severe fatty infiltration.

Intramuscular fat infiltration evaluated by magnetic resonance imaging predicts the extensibility of the supraspinatus muscle

INTRODUCTION

Rotator cuff (RC) tears result in muscle atrophy and fat infiltration within the RC muscles. An estimation of muscle quality and deformation, or extensibility, is useful in selecting the most appropriate surgical procedure. We determined if noninvasive quantitative assessment of intramuscular fat using MRI could be used to predict extensibility of the supraspinatus muscle.

METHODS

Seventeen cadaveric shoulders were imaged to assess intramuscular fat infiltration. Extensibility and histological evaluations were then performed.

RESULTS

Quantitative fat infiltration positively correlated with histological findings and presented a positive correlation with muscle extensibility (r = 0.69; P = 0.002). Extensibility was not significantly different between shoulders graded with a higher fat content versus those with low fat when implementing qualitative methods.

DISCUSSION

A noninvasive prediction of whole-muscle extensibility may directly guide pre-operative planning to determine if the torn edge could efficiently cover the original footprint while aiding in postoperative evaluation of RC repair. Muscle Nerve 57: 129-135, 2018.

A semi-automated quantitative CT method for measuring rotator cuff muscle degeneration in shoulders with primary osteoarthritis

BACKGROUND

Rotator cuff muscle degeneration is an important parameter to consider when planning shoulder arthroplasty.

HYPOTHESIS

We hypothesized that rotator cuff muscle degeneration is correlated with scapulohumeral subluxation in patients planned for anatomical total shoulder arthroplasty (TSA).

MATERIALS AND METHODS

We developed a semi-automated quantitative CT method to measure rotator cuff muscle degeneration, and retrospectively analyzed 107 preoperative shoulder CT scans of patients with primary osteoarthritis. On a standardized sagittal-oblique CT slice perpendicular to the scapular axis, two observers measured the cross-sectional areas of residual rotator cuff muscle tissues, normalized by the estimated area of healthy muscles. Muscle degeneration was quantified in a semi-automated manner, and divided into atrophy and fatty infiltration. Scapulohumeral subluxation was determined in 3D as the distance between the humeral head center and the glenoid surface center, projected on the same CT slice, and normalized by the humeral head radius. We tested all potential correlations between muscle degeneration and scapulohumeral subluxation.

RESULTS

Muscle degeneration, primarily due to atrophy, predominated in the supraspinatus; it varied from 0.8% to 88.8%. Scapulohumeral subluxation varied from 2.5% to 72.9%, and was mainly in a posterior and postero-superior orientation. There was a significant but weak correlation between the amount of subluxation and both supraspinatus (R=0.207, P=0.032) and infraspinatus (R=0.225, P=0.020) degeneration. Inter- and intra-observer reproducibility of muscle degeneration measurements were both excellent (ICCs range=0.955-0.987 and 0.971-0.988, respectively).

CONCLUSION

This new semi-automated CT method allows to quantitatively and reproducibly measure rotator cuff muscle degeneration in shoulders with primary osteoarthritis. Muscle degeneration is weakly correlated with scapulohumeral subluxation in patients planned for anatomical TSA.

LEVEL OF EVIDENCE

Level IV.

TYPE OF STUDY

Diagnostic retrospective study.

Classification of full-thickness rotator cuff lesions: a review

Rotator cuff lesions (RCL) have considerable variability in location, tear pattern, functional impairment, and repairability.

Historical classifications for differentiating these lesions have been based upon factors such as the size and shape of the tear, and the degree of atrophy and fatty infiltration. Additional recent descriptions include bipolar rotator cuff insufficiency, ‘Fosbury flop tears’, and musculotendinous lesions.

Recommended treatment is based on the location of the lesion, patient factors and associated pathology, and often includes personal experience and data from case series. Development of a more comprehensive classification which integrates historical and newer descriptions of RCLs may help to guide treatment further.

Cite this article: Lädermann A, Burkhart SS, Hoffmeyer P, et al. Classification of full thickness rotator cuff lesions: a review. EFORT Open Rev 2016;1:420-430. DOI: 10.1302/2058-5241.1.160005.

Comparing the MRI-based Goutallier Classification to an experimental quantitative MR spectroscopic fat measurement of the supraspinatus muscle

BACKGROUND

The Goutallier Classification is a semi quantitative classification system to determine the amount of fatty degeneration in rotator cuff muscles. Although initially proposed for axial computer tomography scans it is currently applied to magnet-resonance-imaging-scans. The role for its clinical use is controversial, as the reliability of the classification has been shown to be inconsistent. The purpose of this study was to compare the semi quantitative MRI-based Goutallier Classification applied by 5 different raters to experimental MR spectroscopic quantitative fat measurement in order to determine the correlation between this classification system and the true extent of fatty degeneration shown by spectroscopy.

METHODS

MRI-scans of 42 patients with rotator cuff tears were examined by 5 shoulder surgeons and were graduated according to the MRI-based Goutallier Classification proposed by Fuchs et al. Additionally the fat/water ratio was measured with MR spectroscopy using the experimental SPLASH technique. The semi quantitative grading according to the Goutallier Classification was statistically correlated with the quantitative measured fat/water ratio using Spearman's rank correlation.

RESULTS

Statistical analysis of the data revealed only fair correlation of the Goutallier Classification system and the quantitative fat/water ratio with R = 0.35 (p < 0.05). By dichotomizing the scale the correlation was 0.72. The interobserver and intraobserver reliabilities were substantial with R = 0.62 and R = 0.74 (p < 0.01).

CONCLUSION

The correlation between the semi quantitative MRI based Goutallier Classification system and MR spectroscopic fat measurement is weak. As an adequate estimation of fatty degeneration based on standard MRI may not be possible, quantitative methods need to be considered in order to increase diagnostic safety and thus provide patients with ideal care in regard to the amount of fatty degeneration. Spectroscopic MR measurement may increase the accuracy of the Goutallier classification and thus improve the prediction of clinical results after rotator cuff repair. However, these techniques are currently only available in an experimental setting.

Supraspinatus Intramuscular Calcified Hematoma or Necrosis Associated with Tendon Tear

Introduction. Rotator cuff intramuscular calcification is a rare condition usually caused by heterotopic ossification and myositis ossificans. Case Presentation. We describe a patient with voluminous calcified mass entrapped in supraspinatus muscle associated with corresponding tendon tear. Histological examination corresponded to a calcified hematoma or necrosis. Patient was surgically managed with open excision of the calcified hematoma and rotator cuff arthroscopic repair. At 6 months, supraspinatus muscle was healed, and functional outcome was good. Discussion and Conclusion. We hypothesized that supraspinatus intramuscular calcified hematoma was responsible for mechanical stress on the tendon. This association has never been described.

What is the Best Clinical Test for Assessment of the Teres Minor in Massive Rotator Cuff Tears?

BACKGROUND

Few studies define the clinical signs to evaluate the integrity of teres minor in patients with massive rotator cuff tears. CT and MRI, with or without an arthrogram, can be limited by image quality, soft tissue density, motion artifact, and interobserver reliability. Additionally, the ill-defined junction between the infraspinatus and teres minor and the larger muscle-to-tendon ratio of the teres minor can contribute to error. Therefore, we wished to determine the validity of clinical testing for teres minor tears.

QUESTION/PURPOSES

The aim of this study was to determine the accuracy of commonly used clinical signs (external rotation lag sign, drop sign, and the Patte test) for diagnosing the teres minor's integrity.

METHODS

We performed a prospective evaluation of patients referred to our shoulder clinic for massive rotator cuff tears determined by CT arthrograms. The posterosuperior rotator cuff was examined clinically and correlated with CT arthrograms. We assessed interobserver reliability for CT assessment and used three different clinical tests of teres minor function (the external rotation lag sign, drop sign, and the Patte test). One hundred patients with a mean age of 68 years were available for the analysis.

RESULTS

The most accurate test for teres minor dysfunction was an external rotation lag sign greater than 40°, which had a sensitivity of 100% (95% CI, 80%-100%) and a specificity of 92% (95% CI, 84%-96%). External rotation lag signs greater than 10° had a sensitivity of 100% (95% CI, 80%-100%) and a specificity of 51% (95% CI, 40%-61%). The Patte sign had a sensitivity of 93% (95% CI, 70%-99%) and a specificity of 72% (95% CI, 61%-80%). The drop sign had a sensitivity of 87% (95% CI, 62%-96%) and a specificity of 88% (95% CI, 80%-93%). An external rotation lag sign greater than 40° was more specific than an external rotation lag sign greater than 10° (p < 0.001), and a Patte sign (p < 0.001), but was not more specific than the drop sign (p < 0.47). There was poor correlation between involvement of the teres minor and loss of active external rotation.

CONCLUSIONS

Clinical signs can predict anatomic patterns of teres minor dysfunction with good accuracy in patients with massive rotator cuff tears. This study showed that the most accurate test for teres minor dysfunction is an external rotation lag sign and that most patients' posterior rotator cuff tears do not lose active external rotation. Because imaging is not always accurate, examination for integrity of the teres minor is important because it may be one of the most important variables affecting the outcome of reverse shoulder arthroplasty for massive rotator cuff tears, and the functional effects of tears in this muscle on day to day activities can be significant. Additionally, teres minor integrity affects the outcomes of tendon transfers, therefore knowledge of its condition is important in planning repairs.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Outcome and value of reverse shoulder arthroplasty for treatment of glenohumeral osteoarthritis: a matched cohort

BACKGROUND

Total shoulder arthroplasty (TSA) is commonly used to treat glenohumeral osteoarthritis (GHOA) with an intact rotator cuff. Recently, reverse shoulder arthroplasty (RSA) has been used for GHOA patients who are elderly or have eccentric glenoid wear. We evaluated patients with GHOA scheduled to have TSA but who were changed to RSA because of intraoperative difficulties with the glenoid component or instability and compared them with a cohort that underwent TSA to determine if the groups had similar outcomes.

METHODS

We identified 24 consecutive GHOA patients who underwent RSA and matched them to 96 patients who underwent TSA. Glenoid wear and rotator cuff musculature were assessed with preoperative computed tomography scans. Direct hospital costs of the procedure were collected.

RESULTS

Postoperative American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, and range of motion were similar between the 2 groups. Five TSA patients had radiographic glenoid loosening, whereas no RSA patients did. Neither group required a revision. One RSA patient required surgery for treatment of a periprosthetic fracture. RSA was $7274 more costly than TSA, related mainly to implant cost.

CONCLUSIONS

Patients with GHOA who were converted intraoperatively to RSA because of improper seating of the glenoid trial or persistent posterior subluxation had outcomes comparable to those of a similar group of patients in whom TSA was performed. At midterm follow-up, TSA is associated with lower cost than RSA. The higher rate of radiographic loosening in the TSA group warrants longer follow-up to assess revision costs. In cases in which a TSA cannot be performed with confidence, RSA is a reasonable alternative.

FATTY MUSCLE INFILTRATION IN CUFF TEAR: PRE AND POST OPERATIVE EVALUATION BY MRI

Objective: To evaluate the fatty infiltration and atrophy of the supraespinatus in the pre- and postoperative of a rotator cuff lesion (RCL), by MRI. Methods: Ten patients with full-thickness rotator cuff tears who had undergone surgical arthroscopic rotator cuff repair between September and December 2011 were included. This is a prospective study, with analysis and comparison of fatty infiltration and atrophy of the supraespinatus. The occupation ratio was measured using the magic selection tool in Adobe Photoshop CS3^(r) on T1 oblique sagittal Y-view MRI. Through Photoshop, the proportion occupied by the muscle belly regarding its fossae was calculated. Results: There was a statistically significant increase in the muscle ratio (p=0.013) comparing images pre and postoperative, analyzed by the Wilcoxon T test. Conclusion: The proportion of the supraspinal muscle above the pit increases in the immediate postoperative period, probably due to the traction exerted on the tendon at the time of repair. Level of Evidence II, Cohort Study.

Magnetic resonance rotator cuff fat fraction and its relationship with tendon tear severity and subject characteristics

BACKGROUND

Compared with the Goutallier classification, chemical shift-based magnetic resonance (MR) fat quantification has superior reliability and accuracy in evaluation of muscle fatty infiltration. We used this method to assess the relationship between rotator cuff (RC) muscle fat fractions, tendon disease severity, and subject characteristics.

METHODS

In total, 182 subjects with shoulder symptoms underwent shoulder MR imaging including additional sequences for fat quantitation. Then, fat fraction maps were manually segmented, and custom software was used to compute the fat fraction. Goutallier scores were also obtained. The relationship between fat fraction and tendon tear severity and subject characteristics was assessed with descriptive statistics, analysis of variance, Student t test of different subgroups, and simple and multiple linear regression analysis.

RESULTS

Statistically higher supraspinatus fat fractions were observed in subgroups with tendon tears >3 cm, retraction >1 cm, age >50 years, body mass index (BMI) >30, higher Goutallier score, female gender, and longer symptom duration. A significant linear relationship was seen between RC fat fraction and tendon disease severity, age, and BMI but not symptom duration. Multiple regression models with fat fraction and tendon disease, age, BMI, and gender were significant for all 4 muscles (P < .001). The slope of fatty infiltration increase with age was reduced after adjustment for tendon disease, BMI, and gender.

CONCLUSION

RC fat fraction assessed by chemical shift MR demonstrated a significant linear relationship with tendon tear severity, age, BMI, and gender but not with symptom duration.

Massive rotator cuff tears: definition and treatment

PURPOSE

The aim of this review is to summarise tear pattern classification and management options for massive rotator cuff tears (MRCT), as well as to propose a treatment paradigm for patients with a MRCT.

METHOD

Data from 70 significant papers were reviewed in order to define the character of reparability and the possibility of alternative techniques in the management of MRCT.

RESULTS

Massive rotator cuff tears (MRCT) include a wide panoply of lesions in terms of tear pattern, functional impairment, and reparability. Pre-operative evaluation is critical to successful treatment. With the advancement of medical technology, arthroscopy has become a frequently used method of treatment, even in cases of pseudoparalytic shoulders. Tendon transfer is limited to young patients with an irreparable MRCT and loss of active rotation. Arthroplasty can be considered for the treatment of a MRCT with associated arthritis.

CONCLUSION

There is insufficient evidence to establish an evidence-based treatment algorithm for MRCTs. Treatment is based on patient factors and associated pathology, and includes personal experience and data from case series.

Magnetic resonance imaging criteria for the assessment of the rotator cuff after repair: a systematic review

PURPOSE

The purpose of this systematic review was to detect the reliability of the currently available magnetic resonance imaging measurements used in the evaluation of repaired rotator cuff.

METHODS

Search was performed using major electronic databases from their inception to February 2014. All studies reporting post-operative magnetic resonance assessment after rotator cuff repair were included. After the identification of available magnetic resonance criteria, reliability studies were further analysed. Descriptive statistics were used to summarize findings. Methodological quality was assessed using the Quality Appraisal of Reliability Studies checklist.

RESULTS

One hundred and twenty studies were included in the review. Twenty-six different criteria were identified. Ten studies reported inter-observer reliability, and only two assessed intra-observer reliability of some of the identified criteria. Structural integrity was the most investigated criterion. The dichotomized Sugaya's classification showed the highest reliability (k = 0.80-0.91). All other criteria showed moderate to low inter-observer reliability. Tendon signal intensity and footprint coverage showed a complete discordance. Intra-observer reliability was high for the presence of structural integrity, and moderate to low for all other criteria. Methodological quality was high only for one study and moderate for three studies.

CONCLUSIONS

Twenty-six different criteria described by multiple classification systems have been identified for the magnetic resonance assessment of rotator cuff after repair. Reliability of most of them has not been analysed yet. With the data available, only the presence of structural integrity showed good intra- and inter-observer agreement.

LEVEL OF EVIDENCE

Systematic review of descriptive and qualitative studies, Level IV.

Reliability of magnetic resonance imaging assessment of rotator cuff: the ROW study

BACKGROUND

Physiatrists encounter patients with rotator cuff disorders, and imaging is frequently an important component of their diagnostic assessment. However, there is a paucity of literature on the reliability of magnetic resonance imaging (MRI) assessment between shoulder specialists and musculoskeletal radiologists.

OBJECTIVE

We assessed inter- and intrarater reliability of MRI characteristics of the rotator cuff.

DESIGN

Cross-sectional secondary analyses in a prospective cohort study.

SETTING

Academic tertiary care centers.

PATIENTS

Subjects with shoulder pain were recruited from orthopedic and physiatry clinics.

METHODS

Two shoulder-fellowship-trained physicians (a physiatrist and a shoulder surgeon) jointly performed a blinded composite MRI review by consensus of 31 subjects with shoulder pain. Subsequently, MRI was reviewed by one fellowship-trained musculoskeletal radiologist.

MAIN OUTCOME MEASUREMENTS

We calculated the Cohen kappa coefficients and percentage agreement among the 2 reviews (composite review of 2 shoulder specialists versus that of the musculoskeletal radiologist). Intrarater reliability was assessed among the shoulder specialists by performing a repeated blinded composite MRI review. In addition to this repeated composite review, only one of the physiatry shoulder specialists performed an additional review.

RESULTS

Interrater reliability (shoulder specialists versus musculoskeletal radiologist) was substantial for the presence or absence of tear (kappa 0.90 [95% confidence interval {CI}, 0.72-1.00]), tear thickness (kappa 0.84 [95% CI, 0.70-0.99]), longitudinal size of tear (kappa 0.75 [95% CI, 0.44-1.00]), fatty infiltration (kappa 0.62 [95% CI, 0.45-0.79]), and muscle atrophy (kappa 0.68 [95% CI, 0.50-0.86]). There was only fair interrater reliability of the transverse size of tear (kappa 0.20 [95% CI, 0.00-0.51]). The kappa for intrarater reliability was high for tear thickness (0.88 [95% CI, 0.72-1.00]), longitudinal tear size (0.61 [95% CI, 0.22-0.99]), fatty infiltration (0.89 [95% CI, 0.80,-0.98]), and muscle atrophy (0.87 [95% CI, 0.76-0.98]). Intrarater reliability for the individual shoulder specialist was similar to that of the composite reviews.

CONCLUSIONS

There was high interrater and intrarater reliability for most findings on shoulder MRI. Analysis of our data supports the reliability of MRI assessment by shoulder specialists for rotator cuff disorders.

Relationship between massive chronic rotator cuff tear pattern and loss of active shoulder range of motion

BACKGROUND

Management of massive chronic rotator cuff tears remains controversial, with no clearly defined clinical presentation as yet. The purpose of the study was to evaluate the effect of tear size and location on active motion in patients with chronic and massive rotator cuff tears with severe muscle degeneration.

METHODS

One hundred patients with massive rotator cuff tears accompanied by muscle fatty infiltration beyond Goutallier stage 3 were prospectively included in this study. All patients were divided into 5 groups on the basis of tear pattern (supraspinatus, superior subscapularis, inferior subscapularis, infraspinatus, and teres minor). Active range of shoulder motion was assessed in each group and differences were analyzed.

RESULTS

Active elevation was significantly decreased in patients with 3 tear patterns involved. Pseudoparalysis was found in 80% of the cases with supraspinatus and complete subscapularis tears and in 45% of the cases with tears involving the supraspinatus, infraspinatus, and superior subscapularis. Loss of active external rotation was related to tears involving the infraspinatus and teres minor; loss of active internal rotation was related to tears of the subscapularis.

CONCLUSIONS

This study revealed that dysfunction of the entire subscapularis and supraspinatus or 3 rotator cuff muscles is a risk factor for pseudoparalysis. For function to be preserved in patients with massive chronic rotator cuff tears, it may be important to avoid fatty infiltration with anterior extension into the lower subscapularis or involvement of more than 2 rotator cuff muscles.

A positive tangent sign predicts the repairability of rotator cuff tears

HYPOTHESIS

We hypothesize that patients with a positive tangent sign will have rotator cuff tears that are not able to be repaired primarily.

METHODS

We performed a retrospective review of the charts of patients who had undergone surgery for repair of a rotator cuff tear. The operative note was reviewed to determine whether the cuff tear was primarily repaired. The magnetic resonance imaging study of each patient was reviewed to assess for a positive or negative tangent sign. The reviewer was blinded to the result of each measurement.

RESULTS

Eighty-one patients met the inclusion criteria. Of the 79 included in our analyses, 17 had a positive tangent sign and 62 had a negative tangent sign. There was only 1 patient with a negative tangent sign who had an irreparable rotator cuff tear. There were 3 patients with a positive tangent sign who had a repairable rotator cuff. With a pretest prevalence of irreparable tears of 18.9%, a positive finding suggested a post-test probability of 82.3% with a positive tangent sign and a post-test probability of only 1.6% when the tangent sign was negative.

CONCLUSION

Our results showed decision-making value in both a negative tangent sign and a positive tangent sign. The tangent sign is an easily performed and reproducible tool with good intraobserver and interobserver reliability that is a powerful predictor of whether a rotator cuff tear will be repairable.

Assessment of fatty degeneration of the gluteal muscles in patients with THA using MRI: reliability and accuracy of the Goutallier and quartile classification systems

The purpose of this study was to quantify the performance of the Goutallier classification for assessing fatty degeneration of the gluteus muscles from magnetic resonance (MR) images and to compare its performance to a newly proposed system. Eighty-four hips with clinical signs of gluteal insufficiency and 50 hips from asymptomatic controls were analyzed using a standard classification system (Goutallier) and a new scoring system (Quartile). Interobserver reliability and intraobserver repeatability were determined, and accuracy was assessed by comparing readers' scores with quantitative estimates of the proportion of intramuscular fat based on MR signal intensities (gold standard). The existing Goutallier classification system and the new Quartile system performed equally well in assessing fatty degeneration of the gluteus muscles, both showing excellent levels of interrater and intrarater agreement. While the Goutallier classification system has the advantage of being widely known, the benefit of the Quartile system is that it is based on more clearly defined grades of fatty degeneration.

Arm lengthening after reverse shoulder arthroplasty: a review

PURPOSE

The purpose of this review is to provide a better understanding of biomechanical changes induced by reverse shoulder arthroplasty (RSA), discuss the different techniques of radiographic assessment of upper limb lengthening after RSA and determine the ideal soft tissue tension that provides the best functional outcome without increasing the risk of complications.

METHODS

Inclusion criteria were articles in which the primary interest was the technique of measuring upper-extremity lengthening after complications related to lengthening and its role in postoperative function; those written in English, French or German; and those that provided evidence levels I-IV relevant to search terms.

RESULTS

Seven articles met our inclusion criteria. Postoperatively, changes in humeral length varied from minus five to five millimetres, and changes in upper-extremity length varied from 15 mm to 27 mm. The acromiohumeral distance averaged 23 mm. Humeral and arm shortening increased the risk of dislocation and led to poor anterior active elevation. The type of surgical approach did not play a role in postoperative function. Subclinical neurological lesions were frequent.

CONCLUSIONS

Studies in this systematic review indicate that deltoid tensioning by restoring humeral length and increasing the acromiohumeral distance is critical for adequate postoperative function and to prevent dislocation. Excessive arm lengthening should be avoided, with zero to two centimetres of lengthening being a reasonable goal to avoid postoperative neurological impairment.