Single slice MR image estimation of 3D supraspinatus intramuscular fatty infiltration in older adults: relevance for clinical practice and research.

OBJECTIVE: (1) To compare older adults stratified by supraspinatus tendon tear status (STT status)-no tear (Intact), partial-thickness (PT) tear, full-thickness (FT) tear-by 3D Dixon fat fraction (3D-FF); 2D fat fraction (2D-FF); and 2D Goutallier grade (2D-GG) at the Y-shaped view, and 1.4 cm and 2.8 cm medial to the Y-shaped view. Stratified by STT status to determine (2) correlation of 3D-FF with 2D-FF and 2D-GG and (3) inter-rater reliability at and medial to the Y-shaped view. MATERIALS AND METHODS: Forty-five volunteers ≥ 60 years recruited prospectively received shoulder MRI. 3D-FF and 2D-FF were measured on 6-point-Dixon MRI by three trainees. Goutallier grade was assessed on T1-weighted MRI by three fellowship-trained diagnostic radiologists. Descriptive, reliability, and correlation analyses were performed. RESULTS: Groups showed no difference in age. The FT group showed higher (p < 0.05) mean 3D-FF (14.09% ± 10.99%), mean 2D-FF (1.4 cm medial to Y-shaped view, 14.91% ± 12.11%; 2.8 cm medial to Y-shaped view, 13.32% ± 9.48%), and mean 2D-GG (Y-shaped view, 1.71 ± 0.78; 1.4 cm medial to Y-shaped view, 1.71 ± 0.69; 2.8 cm medial to Y-shaped view, 1.71 ± 0.72), relative to Intact/PT groups. 3D-FF showed strong correlation with 2D-FF among all groups/all analyses (rho, 0.80-0.98; p < 0.001). 3D-FF showed strong correlation with 2D-GG for all FT group analyses (rho, 0.85-0.91; p < 0.05). 3D-FF showed moderate-to-strong correlation considering all Intact/PT group analyses (rho, 0.51-0.79; p < 0.50). Dixon fat fraction showed excellent reliability for all groups (≥ 0.884, intraclass correlation coefficient). Goutallier grade showed excellent reliability for FT group (0.771, weighted Fleiss's kappa) but poor (0.294) and fair (0.502) for Intact and PT groups, respectively. CONCLUSION: Single slice MR image estimation of 3D supraspinatus intramuscular fatty infiltration has merit for continued use in clinical populations requiring potential rotator-cuff-repair surgery. However, Dixon fat fraction should be prioritized for use in research over Goutallier grade due to superior reliability.

Arthroplasty-Related Pseudotumor of the Scapula: Case Report and Review of the Literature.

Arthroplasty-related pseudotumors are nonneoplastic and noninfectious inflammatory masses that are typically associated with adverse reaction to metal debris. Pseudotumors most commonly occur in the setting of metal-on-metal joint replacements at the hip. However, the presentation of pseudotumor at the shoulder is exceedingly rare. In this article, we reported a case of arthroplasty-related pseudotumor of the scapula. Clinical history, radiologic signs, and tissue analysis are described. Knowledge of this rare diagnosis will support clinical decision making for teams of radiologists, pathologists, oncologists, and orthopaedic surgeons who provide care for patients presenting with suspicious shoulder masses.

Shoulder Dysfunction and Mobility Limitation in Aging.

Mobility limitation is common among older populations and is a major burden to public health. While lower extremity dysfunction is a known contributor, the influence of shoulder dysfunction on mobility is less well understood. Shoulder pain and rotator cuff tear are common causes of shoulder dysfunction, and both ailments are highly prevalent in older adults. This article discusses shoulder pain and rotator cuff tear as contributors to shoulder dysfunction and describes the association of shoulder dysfunction with mobility limitation in older adults.

Shoulder pain, health-related quality of life and physical function in community-dwelling older adults.

The impact of shoulder pain on health-related quality of life and physical function among community-dwelling older adults (>60 years) not seeking medical care is not well understood. Forty-four community-dwelling older adult volunteers with low comorbidity were stratified into two groups by the presence (n = 18) or absence (n = 26) of shoulder pain. Participants completed the 36-Item Short Form and American Shoulder and Elbow Surgeon surveys and received shoulder range of motion and magnetic resonance imaging testing. Participants with shoulder pain perceived more difficulty accomplishing usual tasks secondary to their physical and emotion health and displayed inferior shoulder function, relative to participants without shoulder pain. This study suggests that shoulder pain reduces quality of life and physical function in the population of community-dwelling older adults not seeking medical evaluation for their symptoms.

Association of Shoulder Dysfunction with Mobility Limitation Among Older Adults in the Baltimore Longitudinal Study of Aging.

Association between lower extremity dysfunction and mobility limitation in older adults is well-established; whereas, the impact of upper extremity dysfunction on mobility remains unclear. Since lower extremity dysfunction does not explain all mechanisms that contribute to mobility limitation, more holistic hypotheses that explain reduced mobility in older populations are needed. The shoulders facilitate dynamic stability for ambulation, but the impact of shoulder dysfunction on mobility is poorly understood. This study examined the cross-sectional association of restricted shoulder elevation and external rotation range of motion (ROM) with poor lower extremity function and walking endurance capacity among 613 older adults aged 60 years and older in the Baltimore Longitudinal Study of Aging. Results showed that persons with abnormal shoulder elevation or external rotation ROM were 2.5 to 4.5 times more likely to perform poorly on the expanded Short Physical Performance Battery (p < .050) and the fast-paced 400 m walk test (p < .050), relative to participants with normal shoulder ROM. These findings provide nascent preliminary evidence that shoulder dysfunction is associated with mobility limitation and suggest that future studies are needed to clarify its impact on mobility and to develop novel interventions to improve prevention or mitigation of age-related declines in mobility.

Extra-capsular floating fat at the extremity: a review.

Extra-capsular floating fat may present in a variety of non-articular locations at the extremity. Manifestation of floating fat or fat-fluid level(s) outside of a joint is a marker of trauma or infection. Recognizing radiologic sign(s) of extra-capsular floating fat can aid radiologists to provide an informed differential diagnosis and facilitate clinical care. This review discusses the etiology, mechanisms, and imaging appearance of extracapsular floating fat in specific anatomic and non-anatomic locations at the extremity.

Estimating 3D supraspinatus intramuscular fatty infiltration in older adults: a pilot study.

BACKGROUND: A recent report suggests that semi-quantitative two-dimensional Goutallier grade (2D-GG) correlates poorly with quantitative three-dimensional Dixon fat fraction (3D-Dixon-FF) on magnetic resonance imaging (MRI). PURPOSE: To determine whether the finding of poor correlation of supraspinatus 3D-Dixon-FF with 2D-GG is reproducible, and to determine the strength of the correlation of 3D-Dixon-FF with quantitative 2D Dixon fat fraction (2D-Dixon-FF). MATERIAL AND METHODS: Ten adults aged ≥60 years were recruited prospectively received shoulder MRI. 2D-Dixon-FF and 3D-Dixon-FF were measured on 6-point Dixon fat fraction maps. 2D-GG was rated on T1-weighted images. RESULTS: The mean age of participants was 70.7 ± 3.7 years. The mean 3D-Dixon-FF was 8.3% ± 5.7%; the mean 2D-Dixon-FF was 7.3% ± 4.4%; and the mean 2D-GG was 0.9 ± 0.7. There was a strong correlation for 3D-Dixon-FF with 2D-Dixon-FF (rho = 0.90; P < 0.001) and with 2D-GG (rho = 0.73; P = 0.017). Excellent inter-observer reliability was found for Dixon fat fraction (intraclass correlation coefficient = 0.946), which was good for Goutallier grade (weighted kappa = 0.634). CONCLUSION: Supraspinatus 3D-Dixon-FF had a strong correlation with 2D-Dixon-FF and 2D-GG in our study population.

Gluteal muscle fatty infiltration, fall risk, and mobility limitation in older women with urinary incontinence: a pilot study.

OBJECTIVE: Gluteal muscle quality influences risk of falling and mobility limitation. We sought (1) to compare gluteal muscle fatty infiltration (FI) between groups of older women with urinary incontinence (UI) at risk for falling (at-risk group) and not at risk for falling (not-at-risk group), and (2) to determine correlation of gluteal FI with Timed Up and Go (TUG) and Short Physical Performance Battery (SPPB) performance. MATERIALS AND METHODS: Prospective pilot study of gluteal FI on pelvis MRI for 19 women with UI, aged ≥ 70 years. A musculoskeletal radiologist selected axial T1-weighted MR images; then, two blinded medical student research assistants analyzed gluteal FI by quantitative fuzzy C-means segmentation. TUG and SPPB tests were performed. TUG ≥ 12 s defined participants as at risk for falling. Descriptive, correlation, and reliability analyses were performed. RESULTS: Mean age, 76.3 ± 4.8 years; no difference for age or body mass index (BMI) between the at-risk (n = 5) versus not-at-risk (n = 14) groups. SPPB score (p = 0.013) was lower for the at-risk group (6.4 ± 3.1) than for the not-at-risk group (10.2 ± 1.9). Fuzzy C-means FI-%-estimate differed between the at-risk group and the not-at-risk group for bilateral gluteus medius/minimus (33.2% ± 15.6% versus 19.5% ± 4.1%, p = 0.037) and bilateral gluteus maximus (33.6% ± 15.6% versus 19.7% ± 6.9%, p = 0.047). Fuzzy C-means FI-%-estimate for bilateral gluteus maximus had significant (p < 0.050) moderate correlation with age (rho = - 0.64), BMI (rho = 0.65), and TUG performance (rho = 0.52). Fuzzy C-means FI-%-estimates showed excellent inter-observer and intra-observer reliability (intraclass correlation coefficient, ≥ 0.892). CONCLUSION: Older women with UI at risk for falling have greater levels of gluteal FI and mobility limitation as compared to those not at risk for falling.

Identification of Community-Dwelling Older Adults With Shoulder Dysfunction: A Pilot Study to Evaluate the Disabilities of the Arm, Shoulder and Hand Survey.

Introduction: The Disabilities of the Arm, Shoulder and Hand (DASH) survey estimates the upper limbs' dysfunction in one score, but limited evidence exists to justify use of DASH to screen older adults for shoulder dysfunction at routine health maintenance primary care visits. We sought (1) to determine if the DASH, American Shoulder and Elbow Surgeons (ASES) and Simple Shoulder Test (SST) surveys are related to one another and (2) to determine the relationship of DASH, ASES and SST scores with 36-Item Short Form (SF-36) subscales, shoulder forward flexion range of motion (FF-ROM) and abduction (ABD-ROM) in older adults. Methods: Prospective pilot study of 23 community-dwelling adult volunteers [mean age (± standard deviation), 69.3 ± 6.7 years; range, 61-84 years, with no rotator cuff repair or joint replacement. Shoulder MRI, ROM testing, DASH, ASES, SST, SF-36, Katz activities of daily living (ADLs), and Lawton-Brody instrumental ADLs (IADLs) were completed at one time point. Descriptive and correlation analyses were performed. Results: Means: DASH, 17.4 ± 19.5; ASES, 81.3 ± 19.7; SST, 71.7 ± 28.5; Katz ADLs, 5.9 ± .3; Lawton-Brody IADLs, 8.0 ± .0; FF-ROM, 140.2° ± 31.5°; and ABD-ROM, 128.3° ± 31.9°. Nearly 48% had supraspinatus tendon tear. Correlation among DASH, ASES, and SST was strong (|rho ≥.88|; P < .001). DASH, ASES, and SST had strong correlation (|rho ≥.71|;P < .001) with shoulder FF-ROM and ABD-ROM. DASH had near equivalent or slightly stronger correlation for all SF-36 subscales relative to ASES and SST. DASH showed strong or moderate correlation (P < .05) to most SF-36 subscales. Conclusion: DASH, ASES and SST strongly correlated with one another. DASH, relative to ASES and SST, has similar correlation to shoulder FF-ROM, ABD-ROM and SF-36 subscales in older adults. Our pilot study suggests that the DASH survey has potential utility to identify occult shoulder dysfunction in community-dwelling older adults who have normal Katz ADLs and Lawton-Brody IADLs if administered during routine health maintenance primary care visits.

Fibroadipogenic progenitor cell response peaks prior to progressive fatty infiltration after rotator cuff tendon tear.

Fibroadipogenic progenitor (FAP) cells are implicated as a major source of fatty infiltration (FI) in murine rotator cuff (RC) injury, but FAP cell response after RC tear in a rabbit model is unknown. This study determined whether changes in FAP cell count after an RC tear predate muscle degeneration in a clinically relevant rabbit model. We hypothesized increases in FAP cell count correlate temporally with RC degeneration. New Zealand white rabbits (n = 26) were evaluated at 1, 2, 4, and 6 weeks after unilateral full-thickness tenotomy of supraspinatus and infraspinatus tendons. FI area and adipocyte size were histologically analyzed, muscle density was measured by computerized tomography, and quantification of FAP cells was measured by flow cytometry and immunohistochemistry. The percentage of intrafascicular adipocyte area increased over time in supraspinatus muscle samples (p = 0.03), significantly between 1- and 6-week samples (p = 0.04). There were no differences in perifascicular adipocyte area percentages between time points. Peak increase in FAP cell count occurred at 1-week (p = 0.03), with a decrease in the following weeks. There was a negative correlation between supraspinatus adipocyte area and FAP cell count (p < 0.05). On computed tomography (CT) scan, maximal decrease in muscle density was observed in the 4th to 6th weeks. In summary, FAP cell response occurred early after tenotomy and did not correlate temporally with increases in FI. This suggests that FAP cell response may predate degenerative changes, and early targeting of FAPs before adipocyte maturation could blunt FI after RC tear.

Supraspinatus fatty infiltration on MRI among older adults receiving physical therapy as initial management for clinically suspected rotator cuff tear: A pilot study.

Objectives: Rotator cuff (RC) tear is common among adults ≥60 years, with supraspinatus tear most common. Intramuscular fatty infiltration (FI) on imaging is predictive of long-term outcomes following RC tear. Physical therapists routinely diagnose RC tear only by clinical examination since most do not order imaging studies. Thus, there is limited knowledge about FI in older populations receiving physical therapy (PT) for initial management of RC tear. The primary objective of our pilot study is to determine longitudinal differences in supraspinatus FI over time among older adults receiving PT (PT cohort) for initial management of RC tear relative to older adult volunteers (control cohort), and with secondary objective to evaluate longitudinal self-reported shoulder function over time. Material and Methods: This was a prospective longitudinal cohort study. Forty adults, 60-85 years, were enrolled at baseline; one follow-up visit at ≥6 months. Shoulder magnetic resonance imaging and clinical screening for Charlson comorbidity index (CCI), body mass index (BMI), and American Shoulder and Elbow Surgeon (ASES) score were completed at baseline and follow-up visits. Supraspinatus FI was evaluated by 6-point Dixon fat fraction and Goutallier grade. PT (n = 15) and control (n = 25) cohorts were stratified by supraspinatus status: Intact (no tear), partial-thickness tear (PTT), and full-thickness tear (FTT). Comparisons within cohort were performed by Kruskal-Wallis test and between cohorts by Mann-Whitney U-test. Interobserver reliability was performed for Dixon fat fraction and Goutallier grade. Results: PT cohort at baseline showed no difference for age, BMI, CCI, and ASES score; supraspinatus FI was highest for FTT by Goutallier grade (no tear, 0.5 ± 0.5; PTT, 1.1 ± 0.2; and FTT, 1.5 ± 0.5; P = 0.033) and by Dixon fat fraction (no tear, 4.6% ± 1.4%; PTT, 6.1% ± 1.9%; and FTT, 6.7% ± 2.5%; P = 0.430). Control cohort at baseline showed no difference for age, BMI, CCI, and ASES score; supraspinatus FI was highest for supraspinatus FTT by Dixon fat fraction (no tear, 5.8% ± 1.2%; PTT, 7.1% ± 6.3%; and FTT, 21.4% ± 10.4%; P = 0.034) and by Goutallier grade (no tear, 0.8 ± 0.5; PTT, 1.0 ± 0.6; and FTT, 2.4 ± 1.7; P = 0.141). No difference between similar PT and control cohort subgroups at baseline except no tear groups for ASES score (PT cohort, 58.9 ± 8.2; control cohort, 84.0 ± 21.9; P = 0.049). No differences were identified for Δ-Dixon fat fraction and Δ-Goutallier grade over time in the PT and control cohorts. PT cohort no tear subgroup showed significant improvement (P = 0.042) for Δ-ASES score over time relative to PTT and FTT subgroups; no difference for Δ-ASES score over time in the control cohort. Conclusion: Full-thickness RC tear showed higher levels of FI relative to PTT or no tear at baseline. Our pilot study's trend suggested that older adults receiving PT for initial management of RC tear have full-thickness RC tear for shorter duration based on relative lower levels of FI at baseline as compared to older adult volunteers with full-thickness RC tear. Our pilot study also found that older adults in the PT cohort with no tear had superior shoulder functional recovery by ASES score over time relative to full-thickness and PTTs.

Reliability of supraspinatus intramuscular fatty infiltration estimates on T1-weighted MRI in potential candidates for rotator cuff repair surgery: full-thickness tear versus high-grade partial-thickness tear.

OBJECTIVE: Patients with supraspinatus high-grade partial-thickness tear or full-thickness tear are potential candidates for rotator cuff repair surgery. We sought (1) to compare supraspinatus intramuscular fatty infiltration between these groups by Goutallier grade, fuzzy C-means and an orthopaedic surgeon visible percentage estimate, (2) and to determine the reliability of each method. MATERIALS AND METHODS: We performed a retrospective cross-sectional study of supraspinatus intramuscular fatty infiltration on T1-weighted MR images for 93 shoulders with either supraspinatus partial-thickness tear > 50% tendon thickness or full-thickness tear by Goutallier grade, fuzzy C-means and an orthopaedic surgeon visible percentage estimate, by two observers for each method. Descriptive statistics were performed to compare groups. Inter- and intra-observer reliability was determined. Correlative analysis among the three methods was performed. RESULTS: Significant differences of mean supraspinatus intramuscular fatty infiltration were present when comparing supraspinatus high-grade partial-thickness tear versus full-thickness tears by Goutallier grade (p = 0.004), fuzzy C-means (p = 0.002) and orthopaedic surgeon visible percentage estimate (p = 0.001). There was no significant difference for age (55.0 ± 11.1 years versus 56.1 ± 9.6 years) or sex (35.4% male versus 47.8% male) for supraspinatus high-grade partial-thickness tear and full-thickness tear, respectively. A significant difference existed among the subgroup of full-thickness tears stratified by tear size by all three methods (p < 0.020). Inter- and intra-observer reliability was Goutallier grade 0.590 and 0.624, fuzzy C-means 0.768 and 0.925 and orthopaedic surgeon visible percentage estimate 0.858 and 0.686, respectively. For shoulders with mean Goutallier grade ≥ 2.0, inter-observer reliability was 0.878 and 0.802 for fuzzy C-means and orthopaedic surgeon visible percentage estimate, respectively. A strong correlation was present among the three methods of supraspinatus FI analysis (rho ≥ 0.72). CONCLUSION: Supraspinatus full-thickness tears have higher amounts of intramuscular fatty infiltration compared to high-grade partial-thickness tear. Quantitative fuzzy C-means shows excellent inter-observer reliability for estimating supraspinatus intramuscular fat. Experienced orthopaedic surgeons' semi-quantitative estimation of supraspinatus visible intramuscular fat may offer improved reliability as compared to semi-quantitative Goutallier grade.

Cartiform Implantation for focal cartilage defects in the knee: A 2-year clinical and magnetic resonance imaging follow-up study.

The purpose of this study was to evaluate clinical and magnetic resonance imaging (MRI) outcomes in patients who underwent cryopreserved viable osteochondral allograft (CVOCA) implantation for focal cartilage defects in the knee at a minimum of 2-years postoperatively. This is a retrospective follow-up study of twelve patients who underwent CVOCA implantation from 2013 to 2015 by a single surgeon for a International Cartilage Repair Society (ICRS) grade 3 or 4 chondral defect. Patient-reported outcome (PRO) measurements and MRI were obtained 2-years postoperatively. Collected PRO measures included: International Knee Documentation Committee (IKDC) form; Visual Analog Scale (VAS) pain score; Veterans RAND 12-Item Health Survey (VR-12); Knee Injury and Osteoarthritis Outcome Score (KOOS); and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC). Patients completed a standard return to work and sports/recreation survey. A blinded, fellowship-trained musculoskeletal radiologist independently evaluated each MRI to determine the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Mean follow-up was 2.1 years (2.0-2.3). There were 6 women and 6 men with a mean age of 46.2 ± 11.9 years. Mean PRO scores were: IKDC 72.6 ± 17.4; VAS 2.9 ± 2.8; WOMAC 84.2 ± 15.1; KOOS- Pain 83.8 ± 18.5, Symptoms 77.6 ± 16.0, ADL 88.0 ± 16.9, Sports/Rec 67.7 ± 33.3, QOL 54.8 ± 24.2; and VR-12 PCS 45.0 ± 8.5 and MCS 51.1 ± 9.5. The mean MOCART score was 59.5 ± 12.9. To our knowledge, this is the largest study to report clinical and MRI outcomes of CVOCA implantation in the knee. With positive functional outcomes and lack of failures at 2-year follow-up, CVOCA is a promising treatment option for focal chondral defects in the knee. STUDY DESIGN: Retrospective case series, Level of evidence 4.

Correlation of Quantitative Versus Semiquantitative Measures of Supraspinatus Intramuscular Fatty Infiltration to Shoulder Range of Motion and Strength: A Pilot Study.

PURPOSE: The relationship of magnetic resonance imaging (MRI) measures of rotator cuff intramuscular fatty infiltration (FI) to shoulder range of motion (ROM) and strength are not well understood. Our purpose was to determine if supraspinatus quantitative Dixon fat fraction has superior correlation to shoulder ROM and strength as compared to semiquantitative Goutallier grade. METHODS: Thirty-seven study subjects received shoulder MRI; and measurement of ipsilateral shoulder forward flexion ROM, abduction ROM and abduction strength. Supraspinatus Dixon fat fraction was measured on 6-point Dixon MRI by 2 diagnostic radiology residents. Supraspinatus Goutallier grade was assessed on T1-weighted MRI by 2 musculoskeletal radiologists. Questionnaires recorded demographics. Based on characteristics, study subjects were divided into 3 groups: Group 1, neither shoulder pain nor full-thickness supraspinatus tendon (SST) tear (n = 17; mean age, 63.0 ± 10.1 years); Group 2, positive complaint of shoulder pain but without full-thickness SST tear (n = 7; mean age, 57.4 ± 9.9 years); Group 3, positive complaint of shoulder pain and full-thickness SST tear (n = 13; mean age, 63.6 ± 8.1 years). One-way analysis of variance compared groups. Spearman (rho) rank order correlation was performed to determine correlation of supraspinatus Dixon fat fraction, or Goutallier grade, with measures of ROM and strength for the study population. Reliability analyses were performed for Dixon fat fraction and Goutallier grade. RESULTS: No significant differences were present among groups for age. Significant differences existed among groups for forward flexion ROM (P= 0.001), abduction ROM (P < 0.001), Dixon fat fraction (P = 0.004) and Goutallier grade (P = 0.012). Dixon fat fraction showed statistically significant inverse correlations with forward flexion ROM (rho = -0.47; P = 0.005), abduction ROM (rho = -0.35, P = 0.041), and abduction strength (rho = -0.42; P = 0.013). Goutallier grade demonstrated weak inverse correlation that lacked statistical significance (P > 0.05) for the same measures. Dixon fat fraction showed strong interobserver and intraobserver reliability with intraclass correlation coefficients of 0.956 and 0.999, respectively. Goutallier grade showed poor interobserver (kappa, 0.188) and moderate intraobserver (kappa, 0.608) reliability. CONCLUSION: Supraspinatus Dixon fat fraction has superior correlation to shoulder ROM and strength relative to Goutallier grade on MRI.

Mimickers of Hill-Sachs Lesions [Formula: see text].

The purpose of this article is to describe the imaging appearance, etiology, clinical features, and treatment of rare presentations of common bone and joint diseases known to mimic Hill-Sachs lesions. Knowledge of uncommonly encountered manifestations of ankylosing spondylitis, rheumatoid arthritis, septic joint, hyperparathyroidism, hydroxyapatite deposition disease, malignant bone tumors, and benign bone cysts which mimic traumatic Hill-Sachs lesions is important for radiologists to guide the clinical care of patients who present with shoulder symptoms.

Association of Rotator Cuff Tear Patterns and Intramuscular Fatty Infiltration on Magnetic Resonance Imaging.

OBJECTIVE: The impact of rotator cuff (RC) tear pattern on intramuscular fatty infiltration (FI) is not well understood. The purpose of our study is to determine if differing RC tear patterns are associated with discordant presentations of intramuscular FI. METHODS: Fifty-one adults with full-thickness tear of the posterosuperior RC on shoulder magnetic resonance imaging (MRI) were identified retrospectively. The study subjects were stratified by RC tear pattern: (1) L-shaped tear cohort, (2) crescent-/U-shaped tear cohort, and (3) complete tear cohort. Clinical information pertaining to age, sex, tear size, trauma history, and length of clinical symptoms was recorded from the institution's picture archiving and communication system. Goutallier grade was assessed on oblique sagittal T1-weighted MRI by two orthopedic surgeons and one orthopedic resident. A musculoskeletal radiologist recorded the shape and size of full-thickness RC tears. Descriptive, correlation, and reliability analyses were performed. RESULTS: The L-shaped, crescent-/U-shaped, and compete tear cohorts demonstrated significant differences pertaining to tear size (P < 0.001) and infraspinatus Goutallier grade (P = 0.024), but not supraspinatus Goutallier grade (P = 0.370). Age had strong correlation to supraspinatus Goutallier grade (rs = 0.712, P = 0.031) and infraspinatus Goutallier grade (rs = 0.712, P = 0.029) in the crescent-/U-shaped tear cohort. Tear size had strong correlation to supraspinatus Goutallier grade (rs = 0.796, P = 0.001) and infraspinatus Goutallier grade (rs = 0.793, P = 0.001) in the complete tear cohort. Moderate interobserver agreement was present for supraspinatus (kappa, 0.484) and infraspinatus (kappa, 0.427) Goutallier grade. CONCLUSION: RC tear pattern is associated with different presentations of intramuscular FI at the posterosuperior RC. Full-thickness tears involving the crescent region of the RC cuff are associated with age. Intramuscular FI is associated with RC tear size.