How to discriminate between acute traumatic and chronic degenerative rotator cuff lesions: an analysis of specific criteria on radiography and magnetic resonance imaging

Studying Edema Formation After Release of the Infraspinatus Muscle as an Experimental Model of Rotator Cuff Lesions in Sheep: A Histological Analysis

BACKGROUND

Muscle edema formation and inflammatory processes are early manifestations of acute rotator cuff lesions in sheep. Histological analysis of affected muscles revealed edema formation, inflammatory changes, and muscle tissue disruption in MRs.

HYPOTHESIS

Edema contributes to inflammatory reactions and early muscle fiber degeneration before the onset of fatty infiltration.

STUDY DESIGN

Controlled laboratory study.

METHODS

Osteotomy of the greater tuberosity, including the insertion of the infraspinatus tendon, was performed on 14 sheep. These experimental animal models were divided into 2 groups: a nontrauma group with surgical muscle release alone (7 sheep) and a trauma group with standardized application of additional trauma to the musculotendinous unit (7 sheep). Excisional biopsy specimens of the infraspinatus muscle were taken at 0, 3, and 4 weeks.

RESULTS

Edema formation was histologically demonstrated in both groups and peaked at 3 weeks. At 3 weeks, signs of muscle fiber degeneration were observed. At 4 weeks, ingrowth of loose alveolar and fibrotic tissue between fibers was detected. Fatty tissue was absent. The diameter of muscle fibers increased in both groups, albeit to a lesser degree in the trauma group, and practically normalized at 4 weeks. Immunohistology revealed an increase in macrophage types 1 and 2, as well as inflammatory mediators such as prostaglandin E2 and nuclear factor kappa-light-chain-enhancer of activated B cells.

CONCLUSION

Early muscle edema and concomitant inflammation precede muscle fiber degeneration and fibrosis. Edema formation results from tendon release alone and is only slightly intensified by additional trauma.

CLINICAL RELEVANCE

This study illustrates that early edema formation and inflammation elicit muscle fiber degeneration that precedes fatty infiltration. Should this phenomenon be applicable to human traumatic rotator cuff tears, then surgery should be performed as soon as possible, ideally within the first 21 days after injury.

Rotator cuff muscle fibrosis can be assessed using ultrashort echo time magnetization transfer MRI with fat suppression

Muscle degeneration following rotator cuff tendon tearing is characterized by fatty infiltration and fibrosis. While tools exist for the characterization of fat, the ability to noninvasively assess muscle fibrosis is limited. The purpose of this study was to evaluate the capability of quantitative ultrashort echo time T1 (UTE-T1) and UTE magnetization transfer (UTE-MT) mapping with and without fat suppression (FS) for the differentiation of injured and control rotator cuff muscles and for the detection of fibrosis. A rat model of chronic massive rotator cuff tearing (n = 12) was used with tenotomy of the right supraspinatus and infraspinatus tendons and silicone implants to prevent healing. Imaging was performed on a 3-T scanner, and UTE-T1 mapping with and without FS and UTE-MT with and without FS for macromolecular fraction (MMF) mapping was performed. At 20 weeks postinjury, T1 and MMF were measured in the supraspinatus and infraspinatus muscles of the injured and contralateral, internal control sides. Histology was performed and connective tissue fraction (CTF) was measured, defined as the area of collagen-rich extracellular matrix divided by the total muscle area. Paired t-tests and correlation analyses were performed. Significant differences between injured and control sides were found for CTF in the supraspinatus (mean ± SD, 14.5% ± 3.9% vs. 11.3% ± 3.7%, p = 0.01) and infraspinatus (17.0% ± 5.4% vs. 12.5% ± 4.6%, p < 0.01) muscles, as well as for MMF using UTE-MT FS in the supraspinatus (9.7% ± 0.3% vs. 9.5% ± 0.2%, p = 0.04) and infraspinatus (10.9% ± 0.8% vs. 10.1% ± 0.5%, p < 0.01) muscles. No significant differences between sides were evident for T1 without or with FS or for MMF using UTE-MT. Only MMF using UTE-MT FS was significantly correlated with CTF for both supraspinatus (r = 0.46, p = 0.03) and infraspinatus (r = 0.51, p = 0.01) muscles. Fibrosis occurs in rotator cuff muscle degeneration, and the UTE-MT FS technique may be helpful to evaluate the fibrosis component, independent from the fatty infiltration process.

MRI findings of traumatic and degenerative rotator cuff tears and introduction of the "cobra sign"

Background

A rotator cuff tear (RCT) is a common shoulder diagnosis and its etiology may be acute, traumatic, or chronic degenerative. Differentiation between the 2 etiologies may be important for multiple reasons, but remains difficult based on imaging. Further knowledge about radiographic and magnetic resonance findings to distinguish traumatic from degenerative RCT is needed.

Methods

We analyzed magnetic resonance arthrograms (MRAs) of 96 patients with traumatic or degenerative superior RCT, which were matched according their age and the affected rotator cuff muscle into the 2 groups. Patients older than 66 years of age were excluded from the study to avoid including cases with pre-existing degeneration. In the case of traumatic RCT, the time between the trauma and MRA had to be less than 3 months. Various parameters of the supraspinatus (SSP) muscle-tendon unit were assessed (tendon thickness, presence of a remaining tendon stump at the greater tubercle, magnitude of retraction, layer appearance). The retraction of the 2 SSP layers were individually measured to determine the difference of retraction. Additionally, edema of the tendon and muscle, the tangent- and kinking-sign as well as the newly introduced Cobra-sign (bulging of the distal part of the ruptured tendon with slim configuration of the medial part of the tendon) were analyzed.

Results

Edema within the SSP muscle (sensitivity 13%, specificity 100%, P = .011) or the tendon (sensitivity 86%, specificity 36%, P = .014) are more frequent in traumatic RCT. The same association was found for the kinking-sign (sensitivity 53%, specificity 71%, P = .018) and the Cobra sign (sensitivity 47%, specificity 84%, P = .001). Even though not statistically significant, tendencies were observed toward thicker tendon stumps in traumatic RCT, and greater difference in retraction between the 2 SSP layers in the degenerative group. The cohorts had no difference in the presence of a tendon stump at the greater tuberosity.

Conclusion

Muscle and tendon edema, as well as tendon kinking appearance and the newly introduced cobra-sign are suitable MRA parameters to distinguish between traumatic and degenerative etiology of a superior RTC.

Muscle Edema of Retraction and Pseudo-Fatty Infiltration After Traumatic Rotator Cuff Tears: An Experimental Model in Sheep

Background

Traumatic rotator cuff tears can result in retraction of the tendon and may be associated with muscle edema, which may be confused with fatty infiltration as seen on magnetic resonance imaging (MRI).

Purpose

To describe the characteristics of a type of edema associated with acute retraction of the rotator cuff tendon (termed "edema of retraction") and to highlight the risk of mistaking it with pseudo-fatty infiltration of the rotator cuff muscle.

Study Design

Descriptive laboratory study.

Methods

A total of 12 alpine sheep were used for analysis. On the right shoulder, osteotomy of the greater tuberosity was performed to release the infraspinatus tendon; the contralateral limb acted as the control. MRI was performed immediately after surgery (time zero) and at 2 and 4 weeks postoperatively. T1-weighted, T2-weighted, and Dixon pure-fat sequences were reviewed for hyperintense signals.

Results

Edema of retraction resulted in hyperintense signals around or within the retracted rotator cuff muscle on both T1- and T2-weighted imaging, but there was an absence of hyperintense signals on Dixon pure-fat imaging. This represented pseudo-fatty infiltration. Edema of retraction created a characteristic "ground glass" appearance of the muscle on T1-weighted sequences and was often found in either the perimuscular or intramuscular location of the rotator cuff muscle. Compared to time zero values, a decrease in the percentage of fatty infiltration was observed at 4 weeks postoperatively (16.5% ± 4.0% vs 13.8% ± 2.9%, respectively; P < .005).

Conclusion

The location of edema of retraction was often peri- or intramuscular. Edema of retraction presented as a characteristic "ground glass" appearance of the muscle on T1-weighted sequences and led to a decrease in the fat percentage because of a dilution effect.

Clinical Relevance

Physicians should be aware that this edema can result in a form of pseudo-fatty infiltration, as it is associated with hyperintense signals on both T1- and T2-weighted sequences, and it can be mistaken for fatty infiltration.

Studying Edema Formation After Release of the Infraspinatus Tendon as an Experimental Model of Rotator Cuff Tears in Sheep: A Preliminary Imaging and Morphological Analysis

BACKGROUND

The cause, extent, and role of muscle edema for muscle degeneration are unknown and not considered in the current literature. In vivo experiments were designed to prove muscle edema formation in the early period in a sheep model of acute rotator cuff tears.

HYPOTHESIS

Muscle edema occurs after tendon release with or without additional stretching trauma and may be associated with muscle retraction and subsequent muscle degeneration.

STUDY DESIGN

Controlled laboratory study.

METHODS

A sheep model with acute release of the infraspinatus tendon was used. An osteotomy of the greater tuberosity, including the insertion of the infraspinatus tendon, was performed in 14 sheep. To demonstrate presence of edema, magnetic resonance imaging scans were performed at 0, 2, and 4 weeks using T1-weighted, T2-weighted, proton density-weighted, and Dixon sequences. Excisional biopsy specimens were taken at 0, 3, and 4 weeks (histological results will be reported in a later publication). Two injury models were created: a nontrauma group that consisted of muscle release alone and a trauma group that included additional standardized traction to the musculotendinous unit. Evaluation of T1- and T2-weighted images included calculation of pennation angle, muscle fiber length, signal intensity (edema), and muscle volume. Muscle wet weight and volume were measured at sacrifice.

RESULTS

Edema formation was shown in all sheep and slightly more pronounced in the trauma group, where muscle intensity increased significantly between time point 0 (200 Grey Value (GV)) and weeks 2, 3, and 4 (300 GV). Edema formation started early after tendon release with a plateau between 3 and 4 weeks. Deterioration of muscle fiber bundles began also after tendon release with a peak at 4 weeks. Muscle volume decreased steadily over time.

CONCLUSION

Muscle edema appeared early after rotator cuff tendon release, was more pronounced in the trauma group, and reached a plateau after 3 to 4 weeks. Muscle fatty content decreased within the short period of 4 weeks owing to a dilution effect. Muscle edema seems to be an essential factor in cuff tears and subsequent muscle retraction and degeneration.

CLINICAL RELEVANCE

This study demonstrates a new type of muscle edema of retraction and describes the characteristics of edema associated with a retracted rotator cuff tear.

Anterolateral Acromioplasty Does Not Change the Critical Shoulder Angle and Acromion Index in a Clinically Relevant Amount

PURPOSE

Assessment on whether radiographic parameters of the acromion measured in radiographs change significantly after anterolateral acromioplasty.

METHODS

This retrospective study included patients that underwent an arthroscopic anterolateral acromioplasty between January 2014 and September 2020. n = 435 subjects with high-quality preoperative and postoperative radiographs according to Suter-Henninger criteria were included in the final assessment. All measurements were independently performed by the first and second author in a blinded fashion using dicomPACS software: acromion index (AI), critical shoulder angle (CSA), lateral acromial angle (LAA), beta angle, acromio-humeral distance (AHD), Aoki angle, frontal supraspinatus outlet angle (FSOW), and acromion type, according to Bigliani. SPSS software was used for statistical analysis.

RESULTS

The beta angle and the CSA did not significantly change after operation (alpha power 0.32 and 0.11, respectively). In a subgroup analysis of patients with a pathological CSA >35° (n = 194), the CSA changed from 38.62 (range: 35.08-47.52, SD 2.83) to 38.04 (range: 29.18-48.12, SD 3.77) postoperatively (P = .028) (Fig 8). All other parameters changed significantly after operation (AI, AHD, FSOW, and Aoki; P = .001, LAA; P = .039) (Fig. 9). The interobserver and intraobserver reliability was good to excellent in the majority of measured values. Mean patient age was 59.2 years (range: 18.1-87.1; SD 11.3), mean height was 1.73 meters (range: 1,50-1.98, SD 0.09), mean weight was 80.2 kg (range: 37.0-133.0, SD 16.68), and mean body mass index was 26.6 (range: 0.0-46.1, SD 4.73).

CONCLUSION

Anterolateral acromioplasty producing a flat acromion undersurface did not result in a significant change of the CSA in the study population. Pathological preoperative CSA values of >35° were significantly reduced but not to normal values, but only by a small amount that puts the clinical relevance into question.

LEVEL OF EVIDENCE

IV, diagnostic study, case series.

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

Background:

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

Purpose/Hypothesis:

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

Study Design:

Cohort study; Level of evidence, 3.

Methods:

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

Results:

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

Conclusion:

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

Factors Influencing the Size of a Non-Traumatic Full-Thickness Rotator Cuff Tear: Focusing on Socioeconomic Factors

This study aimed to identify the risk factors for non-traumatic rotator cuff tears in Korean adult patients who underwent surgical treatment, focusing on socioeconomic factors. A retrospective study was conducted with 659 patients who were diagnosed with a full rotator cuff tear and underwent surgical treatment. The outcome variable was the rotator cuff tear size (mm), as indicated by preoperative magnetic resonance imaging. Socioeconomic variables included occupation, education level, insurance type, and residential area. Univariate analyses were used to evaluate the relation between tear size and independent variables, and multivariate regression was used to estimate the effects of socioeconomic factors on tear size after adjusting for other variables. Significant differences were found in mean tear size according to age, occupation, residence area, and symptom duration (p < 0.05) in multivariate regression analysis. Rural residents had a 2.12 mm larger tear size than urban residents. Compared to National Health Insurance patients, the tear size of Medicaid beneficiaries was significantly larger (6.79 mm) in urban areas. The larger the rotator cuff tear, the greater the risk of retear and poor shoulder function. Therefore, policy efforts are required to expand access to medical care for the vulnerable.

Are there differences in arthroscopic and histological features between traumatic and degenerative rotator cuff tears in elderly patients? A prospective dual-center analysis

Background

Discriminating traumatic rotator cuff tears (RCTs) from degenerative RCTs is sometimes difficult in elderly patients because the prevalence of asymptomatic RCTs increases with age. Little intraoperative information is available on the characteristics of traumatic and degenerative RCTs in elderly patients. The purpose of this study was to compare the arthroscopic findings and histological changes of the coracoacromial ligament (CAL) between traumatic and degenerative RCTs in elderly patients.

Methods

Forty-two shoulders of 42 patients aged ≥ 65 years underwent arthroscopic rotator cuff repair. Nineteen patients had traumatic full-thickness RCTs (Group T), and 23 had degenerative full-thickness RCTs (Group D). The quality of the rotator cuff tissue and the condition of the long head of the biceps were examined. The grade of CAL was evaluated both arthroscopically and histologically. The stiffness of the musculotendinous unit was calculated by measuring the force and displacement using a tensiometer. The arthroscopic and histological findings of the two groups were compared.

Results

Although the mean tendon displacement was comparable, the stiffness was different between Group T and Group D (0.56 ± 0.31 and 1.09 ± 0.67 N/mm, respectively; p < 0.001). Both arthroscopic and histological analysis of the CAL showed that the degenerative changes in the CAL were milder in Group T than in Group D (p < 0.001 and p < 0.001, respectively). There was a moderate positive correlation between the arthroscopic findings of CAL degeneration and the histopathological changes in this ligament (r = 0.47, p = 0.002).

Conclusions

Traumatic RCTs were characterized by preserved elasticity of the musculotendinous unit and milder CAL degeneration compared with degenerative RCTs even in elderly patients.

Imaging of traumatic shoulder injuries – Understanding the surgeon’s perspective

Imaging plays a key role in the assessment and management of traumatic shoulder injuries, and it is important to understand how the imaging details help guide orthopedic surgeons in determining the role for surgical treatment. Imaging is also crucial in preoperative planning, the longitudinal assessment after surgery and the identification of complications after treatment. This review discusses the mechanisms of injury, key imaging findings, therapeutic options and associated complications for the most common shoulder injuries, tailored to the orthopedic surgeon’s perspective.

Deciphering acute shoulder trauma with normal initial X-ray: Contributions of ultrasonography and MRI

INTRODUCTION

Shoulder trauma with normal radiographs is a frequent emergency presentation. The predominance of pain makes clinical examination unreliable, and complementary imaging is often needed for diagnosis. The aim of the present study was to assess the contribution of ultrasonography (US) and magnetic resonance imaging (MRI) in deciphering such trauma. The study hypothesis was that MRI can confirm most diagnoses and reveal occult lesions.

METHODS

48 patients with a median age of 33 years (IQR, 22-48.75), admitted to the Emergency Department between February and September 2016, were prospectively included. All had normal X-ray and underwent emergency and deferred emergency (D+7-10) clinical examination, and US and MRI at D+7-14. The same examinations were repeated to establish diagnosis and initiate treatment. MRI was considered as gold-standard for definite diagnosis.

RESULTS

Diagnoses comprised: 14 shoulder contusions; 13 rotator cuff tears; 8 acromioclavicular sprains; 6 fractures: 3 greater tuberosity, 2 humeral head, 1 lateral quarter of the clavicle; 3 subluxations or anterior dislocations with spontaneous reduction; 1 posterior dislocation with spontaneous reduction; 1 case of resorption of calcification in the pectoralis major tendon; 1 case of coracobrachialis strain; and 1 partial pectoralis major detachment. Concordance with final diagnosis was 42% (20/48) on initial clinical examination and 52% (25/48) on reassessment. On US, concordance was 71% (34/48), with 82% positive predictive value for cuff tear and 0% for instability. MRI was contributive in all cases, revealing 48 abnormal signals in 41 patients, thus establishing 48 diagnoses.

CONCLUSION

Except in precise diagnostic situations such as rotator cuff tear, US is not a contributive examination, completely overlooking shoulder instability and bone contusion. MRI should play an increasing role in deciphering these traumas.

LEVEL OF EVIDENCE

II; prospective cohort study.

Acute massive rotator cuff rupture with posterior shoulder dislocation: arthroscopic novel repair of a rare injury. A case report

Acute massive rotator cuff tears and posterior shoulder dislocations are an extremely rare association, and a vast majority are treated by open surgery. We present a case of a man in his 20s who suffered closed left shoulder trauma after a road traffic accident. He was initially diagnosed with posterior shoulder dislocation and a reduction was successfully performed. However, the patient still complained of persistent weakness during active movements. We found a massive rotator cuff tear involving all the rotator cuff tendons, with significant supraspinatus retraction and persistent posterior shoulder subluxation. He underwent an all-arthroscopic repair of the rotator cuff with a double-row technique in the subscapularis, supraspinatus and infraspinatus muscles. Capsular repair and tenodesis of the biceps tendon were also performed. The patient had good recovery, reaching full preinjury function 3 months after surgery with a successful return to his regular activities.

Comparison of tear characteristics, outcome parameters and healing in traumatic and non-traumatic rotator cuff tear: a prospective cohort study

PURPOSE

Acute traumatic and chronic non-traumatic rotator cuff tears are etiologically distinguishable entities. However, prospective studies comparing tear characteristics and outcomes between these two types of tears are lacking. The purpose of this study was to compare the tear characteristics, clinical and functional outcomes, and tendon healing as assessed on magnetic resonance imaging (MRI), between traumatic and non-traumatic rotator cuff tears.

METHODS

MRI proven rotator cuff tears were allocated into two groups according to the history of injury: Group 1 included 28 patients with traumatic tears and group 2 included 33 patients of non-traumatic cuff tears. Both the groups were compared for preoperative tear characteristics (tear size, muscle atrophy, fatty degeneration), range of motion, strength of shoulder abduction and external rotation, functional outcomes, and tendon integrity on MRI, 2 years after the surgery.

RESULTS

Postoperative mean active range of abduction (p = 0.005), abduction strength (p = 0.013), external rotation strength (p = 0.027), University of California at Los Angeles score (p < 0.001), Constant score (p = 0.002), American Shoulder and Elbow Surgeons scores (p = 0.028) and visual analog scale for pain (p = 0.02) were significantly better in group 1 as compared to group 2. The postoperative structural integrity of the cuff on MRI was better in group 1 as compared to group 2, but the values did not reach statistical significance (p = 0.13).

CONCLUSION

Findings from this study suggest that traumatic tears affect younger patients and while having a larger tear size, they have lesser muscle atrophy, fatty degeneration, and tendon retraction. Functional outcomes are better after treatment of traumatic tears as compared to non-traumatic tears. Chronicity of the tear and tendon retraction negatively affected healing in traumatic cuff tears. Muscle atrophy was found to be associated with poorer healing in non-traumatic tears. However, tear size was not associated with healing.

LEVEL OF EVIDENCE

II, Prospective cohort study.

Definition of the terms "acute" and "traumatic" in rotator cuff injuries: a systematic review and call for standardization in nomenclature

BACKGROUND

Although of high relevance for clinical decision making, there exists no consensus throughout the literature of the terms "acute" and "traumatic" used in the classification of rotator cuff tears. With differing definitions, the comparability of outcome studies may be limited. The aim was to provide a detailed systematic review of the definitions used in the literature and present a suggestion for a standardization in nomenclature based on the findings.

METHODS

Four different internet databases were searched in February 2020 using the terms ("acute" OR "traumatic" OR "trauma" OR "athlete" OR "young") AND ("rotator cuff tears" OR "rotator cuff tear" OR "rotator cuff" OR "rotator cuff rupture" OR "supraspinatus" OR "infraspinatus" OR "subscapularis" OR "teres minor"). Prospective, retrospective, cohort and case-control studies as well as case series were included. Systematic reviews, cadaveric or laboratory studies and studies on non-traumatic or non-acute rotator cuff tears were excluded.

RESULTS

The literature search conducted 10,349 articles of which 10,151 were excluded based on the title, 119 based on the abstract and 33 based on the manuscript. A total of 46 studies were finally included for review and subsequently analyzed. Overall, there exists no consensus neither on the term "acute" nor on "traumatic" in the context of rotator cuff tears in the literature. The time span for acute injuries ranged between 2 weeks and 6 months. For traumatic injuries, only 20% of the selected studies described a specific and adequate injury mechanism in combination with adequate imaging.

CONCLUSION

The term "acute" should be reserved for RCT showing muscle edema, wavelike appearance of the central part of the torn tendon and joint effusion, which typically requires adequate imaging within 2 weeks from trauma. Repair of acute tears should occur within 8 weeks from trauma to benefit from possibly superior biological healing capacities. The term "traumatic" should be used for a sudden onset of symptoms in a previously asymptomatic patient, triggered by an adequate trauma, e.g., a fall on the retroverted arm with an axial cranioventral force or a traumatic shoulder dislocation.

Lateral Acromioplasty has a Positive Impact on Rotator Cuff Repair in Patients with a Critical Shoulder Angle Greater than 35 Degrees

BACKGROUND

A Critical Shoulder Angle (CSA), evaluated on plain radiographs, greater than 35° is considered predictive of rotator cuff tears. The present prospective comparative study aimed, firstly, to develop a formula to calculate the amount of acromion that should be resected performing a lateral acromioplasty and, secondly, verify whether lateral acromioplasty to reduce the CSA associated with arthroscopic cuff repair decreased the rate of recurrence of the tears, and impacted favorably on clinical postoperative outcomes.

METHODS

Patients undergoing arthroscopic rotator cuff repair (RCR) for rotator cuff tears with a CSA greater than 35° were included in this study and divided into two groups, based on whether the CSA had been reduced by arthroscopic resection of the lateral portion of the acromion. A new mathematical formula was developed in order to quantify the amount of bone to be resected while performing the lateral acromioplasty. Patients with traumatic tears, previous surgery, osteoarthritis or plain radiographs, not classified as A1 according to Suter-Henninger, were excluded. Clinical and radiographic outcomes were assessed at a minimum of 2 years of follow-up considering the tear size.

RESULTS

289 patients were included in this study. Thirty-seven were lost to follow-up. Group A (Lateral acromioplasty) patients included: 38 small tears, 30 medium tears, 28 large tears and 22 massive tears; Group B (control group) was composed of 40 small tears, 30 medium tears, 30 large tears and 23 massive tears. The Constants Score value and retear Rate were, respectively, significant higher (p = 0.007 and p = 0.004) and lower (p = 0.029 and p = 0.028) in Group A, both in the Small-and Medium-size subgroups. No complications were outlined. The mediolateral width of the acromion was reduced, according to the preoperatively calculated measure.

CONCLUSION

Arthroscopic lateral acromioplasty decreased the CSA within the favorable range (30°-35°) in all patients treated, resecting the amount of bone predicted by the mathematical formula. Lateral acromioplasty is a safe and reproducible technique which may prevent recurrence of rotator cuff tears in patients with small and medium lesions.

LEVEL OF EVIDENCE

II.

Magnetic resonance imaging analysis of rotator cuff tear after shoulder dislocation in a patient older than 40 years

BACKGROUND

This study was designed to evaluate characters of the rotator cuff tear (RCT) recognized after primary shoulder dislocation in patients older than 40.

METHODS

From 2008 to 2019, patients who visited two hospitals after dislocation were retrospectively reviewed. Inclusion criteria were patients over 40 who had dislocation, with magnetic resonance imaging (MRI) undergone. Exclusion criteria were patients who lost to follow-up, combined with any proximal humerus fracture, brachial plexus injury, and previous operation or dislocation history in the ipsilateral shoulder. Also patients who had only bankart or bony bakart lesion in MRI were excluded. We evaluated RCTs that were recognized by MRI after the primary shoulder dislocation with regard to tear size, degree, involved tendons, fatty degeneration, the age when the first dislocation occurred, and the duration until the MRI was evaluated after the dislocation.

RESULTS

Fifty-five RCTs were included. According to age groups, the tear size was increased in coronal and sagittal direction, the number of involved tendons was increased, and the degree of fatty degeneration was advanced in infraspinatus muscle. Thirty-two cases (58.2%) conducted MRI after 3 weeks from the first shoulder dislocation event. This group showed that the retraction size of the coronal plane was increased significantly and the fatty accumulation of the supraspinatus muscle had progressed significantly.

CONCLUSIONS

Age is also a strong factor to affect the feature of RCT after the shoulder dislocation in patients over 40. And the delay of the MRI may deteriorate the degree of tear size and fatty degeneration.

Mobility Assessment of the Supraspinatus in a Porcine Cadaver Model Using a Sensor-Enhanced, Arthroscopic Grasper

Tendon mobility is highly relevant in rotator cuff surgery. Objective data about rotator cuff mobility is rare. Tendon mobility still needs to be evaluated subjectively by the surgeon. This study aims to establish a porcine animal model for mobility analysis of the supraspinatus. In this context, we introduce a sensor-enhanced, arthroscopic grasper (SEAG) suitable for objective intraoperative measurements of tendon mobility in clinical praxis. Tendon mobility of 15 fresh porcine cadaver shoulders with artificial rotator cuff tears was evaluated using the SEAG. Mobility characteristics (load–displacement curves, maximum load, stiffness) were studied and inter- and intraobserver agreement (intraclass correlation coefficient (ICC)) were tested. Factors with a potential adverse effect (plastic deformation and rigor mortis) were also evaluated. All shoulders showed characteristic reproducible load–displacement curves with a nonlinear part at the start, followed by a linear part. Mean maximum load was 28.6 N ± 12.5. Mean stiffness was 6.0 N/mm ± 2.6. We found substantial interobserver agreement (ICC 0.672) and nearly perfect intraobserver agreement (0.944) for maximum load measurement. Inter- (0.021) and intraobserver (0.774) agreement for stiffness was lower. Plastic deformation and rigor mortis were excluded. The animal model demonstrates reliable and in vivo-like measurements of tendon mobility. The SEAG is a reliable tool for tendon mobility assessment.

Imaging of Acute Shoulder Trauma

Acute injuries to the shoulder girdle are common and frequently encountered by the practicing radiologist. The type of injury is highly dependent on the age of the patient and mechanism of trauma with injuries occurring at the site of greatest mechanical weakness. In this review, we discuss the main clinical features and key imaging findings for the most common shoulder injuries. For each injury, we also provide a section on the important features that the orthopedic surgeon needs to know in order to guide surgical versus nonsurgical management.

Midterm results after revision rotator cuff reconstruction: Can ultrasound predict outcome of revision surgery?

PURPOSE

Structural failures after rotator cuff repair are well known, and despite advances and improved techniques in rotator cuff repair (RCR), retear rates remain high. The aim of this study was to (1) evaluate the midterm clinical and radiological outcomes after revision RCR and to (2) analyze whether preoperative ultrasound can predict outcome of open revision rotator cuff repair.

METHODS

Twenty-five patients who underwent revision RCR in a single institution between 2010 and 2012 were retrospectively reviewed at a minimum follow-up of 2 years. The Constant Score (CS) and the Disabilities of the Arm, Shoulder and Hand score were collected. Ultrasound examination was used both before revision surgery and at follow-up to determine tendon integrity.

RESULTS

At the final follow-up, 69.6% patients showed an intact rotator cuff and their CS had improved from 28.3 to 77. 30.4% patients had a persisting rotator cuff defect, and the CS had improved from 24 to 47.7. A preoperative tear size of more than 20 mm from an ultrasound examination could be identified as a factor that would risk structural failure of revision RCR.

CONCLUSION

(1) Clinical outcomes after revision RCR improve in both patients with an intact RC and those with a retear at midterm follow-up. (2) Ultrasound seems to be a useful tool to predict whether reconstruction of recurrent rotator cuff tears is feasible.

LEVEL OF EVIDENCE

IV, Case series.

Risk Factors for Rotator Cuff Disease: An Experimental Study on Intact Human Subscapularis Tendons

Although several studies revealed a multifactorial pathogenesis of degenerative rotator cuff disorders, the impact and interaction of extrinsic variables is still poorly understood. Thus, this study aimed at uncovering the effect of patient- and pathology-specific risk factors that may contribute to degeneration of the rotator cuff tendons. Between 2015 and 2018, 54 patients who underwent arthroscopic shoulder surgery at three specialized shoulder clinics were prospectively included. Using tendon samples harvested from the macroscopically intact subscapularis (SSC) tendon, targeted messenger RNA expression profile analysis was performed in the first cohort (n = 38). Furthermore, histological analyses were conducted on tendon tissue samples obtained from a second cohort (n = 16). Overall, both study cohorts were comparable concerning patient demographics. Results were then analyzed with respect to specific extrinsic factors, such as patient age, body mass index, current as well as previous professions and sport activities, smoking habit, and systemic metabolic diseases. While patient age, sports-activity level, and preexisting rotator cuff lesions were considered to contribute most strongly to tendinopathogenesis, no further coherences were found. With regards to gene expression analysis, change in expression correlated most strongly with patient age and severity of the rotator cuff pathology. Further, chronic disorders increased overall gene expression variation. Taken together, our study provides further evidence that tendon degeneration is the consequence of a multifactorial process and pathological changes of the supraspinatus tendon affect the quality of SSC tendon and most likely vice versa. Therefore, the rotator cuff tendons need to be considered as a unit when managing rotator cuff pathologies. © 2019 The Authors. Journal of Orthopaedic Research^® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society J Orthop Res 38:182-191, 2020.

Posterior dislocation of the long head biceps tendon: a case report, specific radiographic finding, and review of the literature

Posterior dislocation of the long head of the biceps tendon uncommonly occurs with traumatic shoulder injury. The diagnosis is almost always associated with anterior shoulder dislocation which often cannot be reduced. We present a case of traumatic posterior dislocation of the long head of the biceps tendon with no reported history of shoulder dislocation, but instead a rare and specific radiographic finding. The imaging features are described, the relevant literature reviewed, and salient features discussed.

Acute Cuff Tear Repair Trial (ACCURATE): protocol for a multicentre, randomised, placebo-controlled trial on the efficacy of arthroscopic rotator cuff repair

INTRODUCTION

Rotator cuff tear is a very common and disabling condition that can be related to acute trauma. Rotator cuff tear surgery is a well-established form of treatment in acute rotator cuff tears. Despite its widespread use and almost a gold standard position, the efficacy of an arthroscopic rotator cuff repair is still unknown. The objective of this trial is to investigate the difference in outcome between arthroscopic rotator cuff repair and inspection of the shoulder joint defined as placebo surgery in patients 45-70 years of age with an acute rotator tear related to trauma.

METHODS AND ANALYSIS

Acute Cuff Tear Repair Trial (ACCURATE) is a randomised, placebo-controlled, multicentre efficacy trial with sample size of 180 patients. Concealed allocation is done in 1:1 ratio. The randomisation is stratified according to participating hospital, gender and baseline Western Ontario Rotator Cuff Index (WORC). Both groups receive the same standardised postoperative treatment and physiotherapy. The primary outcome measure is the change in WORC score from baseline to 2-year follow-up. Secondary outcome measures include Constant-Murley Score, the Numerical Rating Scale for pain, subjective patient satisfaction and the health-related quality of life instrument 15 dimensions (15D). Patients and outcome assessors are blinded from the allocated intervention. The primary analysis of results will be conducted according to intention-to-treat analysis.

ETHICS AND DISSEMINATION

The study protocol for this clinical trial has been approved by the Ethics Committee of the Hospital District of Southwest Finland and Regional Ethics Committee in Linköping Sweden and Regional Committees for Medical and Health Research Ethics South East in Norway. Every recruiting centre will apply local research approvals. The results of this study will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02885714; Pre-results.

The accuracy of plain radiographs in diagnosing degenerate rotator cuff disease

BACKGROUND

A number of radiographic signs have been previously demonstrated to be associated with degenerative rotator cuff tears. An ability to predict the presence of a tear by radiography would permit the early commencement of appropriate treatment and the avoidance of unnecessary invasive investigations. The aim of the present study was to determine the accuracy of using radiographic signs to predict the presence of a cuff tear on arthroscopy.

METHODS

Fifty consecutive patients who had undergone shoulder arthroscopy and had pre-operative plain radiographs were included. Pre-operative radiographs were reviewed by a consultant shoulder surgeon, a consultant radiologist and a senior clinical fellow for the following signs: acromial spur; subjective reduction of subacromial space; sourcil sign; acromial acetabularization; os acromiale; greater tuberosity cortical irregularity; greater tuberosity sclerosis; humeral head rounding; cyst; and reduction in acromiohumeral head distance.

RESULTS

The presence of tuberosity sclerosis (p < 0.0001), tuberosity irregularities (p < 0.0001), tuberosity cyst (p = 0.004) and sourcil sign (p = 0.019) was associated with the presence of a rotator cuff tear. The combined sensitivity of prediction of tear by the observers following radiographic review was 91.7%, with a combined negative predictive value of 80%.

CONCLUSIONS

The assessment of radiographs by senior clinicians is a useful tool for confirming the absence of a rotator cuff tear.

Degenerative Rotator Cuff Tears: Refining Surgical Indications Based on Natural History Data

Degenerative rotator cuff tears are the most common cause of shoulder pain and have a strong association with advanced aging. Considerable variation exists in surgeons' perceptions on the recommended treatment of patients with painful rotator cuff tears. Natural history studies have better outlined the risks of tear enlargement, progression of muscle degeneration, and decline in the function over time. This information combined with the known factors potentially influencing the rate of successful tendon healing such as age, tear size, and severity of muscle degenerative changes can be used to better refine appropriate surgical indications. Although conservative treatment can be successful in the management of many of these tears, risks to nonsurgical treatment also exist. The application of natural history data can stratify atraumatic degenerative tears according to the risk of nonsurgical treatment and better identify tears where early surgical intervention should be considered.

The prevalence of rotator cuff pathology in the setting of acute proximal biceps tendon rupture

BACKGROUND

The prevalence and severity of concomitant rotator cuff pathology in the setting of proximal biceps tendon ruptures are poorly understood. Concomitant rotator cuff disease may have important implications in the prognosis and natural history of this shoulder condition. Therefore, an observational cohort of patients with an acute rupture of the long head of the biceps tendon (LHBT) was evaluated to determine the prevalence and severity of concomitant rotator cuff disease.

METHODS

Thirty consecutive patients diagnosed with acute proximal biceps tendon rupture were prospectively enrolled. Magnetic resonance imaging of the affected shoulder was obtained in 27 patients and reviewed by a fellowship-trained orthopedic surgeon.

RESULTS

The cohort consisted of 20 men (74%) and 7 women (26%) (mean age, 61.0 years [range, 42-78 years]). The dominant side was involved in 20 injuries (74%), and a low-energy trauma mechanism of injury was involved in 23 (85%). Of the patients, 11 (41%) reported a history of antecedent shoulder pain. Magnetic resonance imaging assessment revealed that 93% of patients had evidence of rotator cuff disease, including 13 full-thickness tears. Of the full-thickness tears, 3 were small, 6 medium, 2 large, and 2 massive. Pathology of the subscapularis tendon was identified in 7 patients (26%).

CONCLUSION

In this cohort, we found LHBT rupture to be highly correlated with the presence of rotator cuff disease, with the majority of patients presenting with full-thickness tears of the supraspinatus. These findings may have important implications in the treatment and prognosis of patients who present with acute LHBT ruptures.

Obesity causes poorer clinical results and higher re-tear rates in rotator cuff repair

BACKGROUND

The purpose of this retrospective study was to report on the functional outcome after both open and arthroscopic rotator cuff (RC) repair in normal weight, pre-obese and obese patients. It was hypothesized that obesity is a negative prognostic factor for clinical outcome and failure for the RC repair.

METHODS

One hundred and forty-six patients who underwent either open or arthroscopic rotator cuff repair between 2006 and 2010 were included in this study. Seventy-five patients (56.7 ± 10.1 years of age) after open RC repair and 71 patients (59.0 ± 9.1 years of age) treated arthroscopically were available for evaluation. In both groups a double-row reconstruction was performed. Patients were divided in three groups according to their body-mass index. The mean follow-up was at 43 ± 16 (minimum 24) months. At follow-up, the clinical outcome was assessed by the DASH and Constant score. An ultrasound of both shoulders was performed in all patients.

RESULTS

The mean BMI was 28.3 ± 5.3 in the arthroscopic group and 27.7 ± 4.3 in the open group. Overall, in both groups similar clinical results were noted [Constant-Murley score 78.3 ± 18.2 arthroscopic vs. 77.0 ± 21.8 for open surgery; DASH 12.7 ± 18.2 arthroscopic vs. 15.6 ± 21.6 for open surgery (p = 0.81)]. Both the failure rate and the clinical outcome were significantly worse for obese patients (BMI > 30, p = 0.007). The failure rate was 15.8% for the normal-weight patients, 8.2% in the pre-obese group and in the obese group 28.6%. The RC repair failure occurred in 11 cases in both groups after arthroscopic or open treatment (15.0%).

CONCLUSIONS

Both the arthroscopic and the open approach showed equivalent clinical results and failure rates. Obesity (BMI > 30) causes less favorable results in the Constant and DASH scores and showed higher re-tear rates.

Acute Rotator Cuff Tears due to Low Voltage Electrical Injury: A Case Report

Since shoulder have a higher proportion of muscle which would have low electrical resistance, there could be more electrical damage to the rotator cuff muscles. We present a patient with acute rotator cuff tear by sudden uncontrolled jerking contractions caused by an electrical shock. A case of 42-year-old man with acute rotator cuff tear due to electrical injury to the shoulder was presented. Magnetic resonance imaging showed a full thickness tear and an undulating appearance of the peripheral end of the torn supraspinatus and infraspinatus muscle, suggesting an acute complete rupture. By arthroscopic surgery, the torn rotator cuff tendons were repaired with a suture bridge technique. At the final follow-up, the patient had a full, pain-free range of motion and had fully recovered shoulder muscle power.

Natural History of Degenerative Rotator Cuff Tears

PURPOSE OF REVIEW

In the past several years, there have been significant advances in our understanding of the natural history of rotator cuff disease. Studies have continued to provide valuable insight into the clinical, radiographic, and anatomic features of these atraumatic tears. Our purpose is to summarize the findings and contributions from these recent high-quality studies.

RECENT FINDINGS

Current research has continued to describe and provide understanding into the natural history of atraumatic rotator cuff disease, including symptom progression, tear enlargement, and the development of arthritis. This knowledge has allowed identification of tears with higher risk of disease progression. Additionally, studies have investigated, with long-term healing data, whether the natural history of degenerative rotator cuff tears can be altered with surgical intervention. Recent studies have shown encouraging mid to long-term healing data and clinical outcome scores for smaller tears in younger patients with minimal fatty infiltration. Future research should focus on obtaining long-term healing data, functional outcome data, and refining surgical indications for rotator cuff repair. Identifying patients with specific tear characteristics amendable to healing will allow us to provide a long-term, durable repair, thus interrupting the natural history of degenerative rotator cuff disease.

Supraspinatus detachment causes musculotendinous degeneration and a reduction in bone mineral density at the enthesis in a rat model of chronic rotator cuff degeneration

BACKGROUND

To evaluate biological strategies that enhance tendon-bone healing in humans, it is imperative that suitable animal models accurately reproduce the pathological changes observed in the clinical setting following a tear. The purpose of the present study was to investigate rotator cuff degeneration in a rat, as well as assess the development of osteopenia at the enthesis following tendon detachment.

METHODS

Eighteen female Wistar rats underwent unilateral detachment of the supraspinatus tendon. Specimens were retrieved at 4 weeks (n = 6), 6 weeks (n = 6) and 9 weeks (n = 6) postoperatively for histological analysis and peripheral quantitative computer tomography.

RESULTS

Three weeks following tendon detachment, there was a significant increase in the modified Movin score, characterized by a loss of muscle mass, fatty infiltration, an increase in musculotendinous cellularity, loss of normal collagen fibre structure/arrangement, rounded tenocyte nuclei and an increase in the number of vascular bundles. This was accompanied by a reduction in bone mineral density at the tendon insertion site. After 3 weeks however, these changes were less prominent.

CONCLUSIONS

The rotator cuff tendon-muscle-bone unit in a rat model 3 weeks after detachment of supraspinatus represents a valid model for investigating rotator cuff degeneration.

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.

A Partial Tear of the Infraspinatus Muscle

A 29-year-old man experienced right shoulder pain and weakness following a forced abduction and external rotation motion performed during an Australian football game. The following morning, the sports medicine physician referred the player for magnetic resonance imaging to exclude infraspinatus rupture, given the external rotation strength deficit. Magnetic resonance imaging revealed a low-grade partial tear of the medial infraspinatus muscle. J Orthop Sports Phys Ther 2016;46(12):1087. doi:10.2519/jospt.2016.0421.

An age- and gender-related three-dimensional analysis of rotator cuff transverse force couple volume ratio in 304 shoulders

PURPOSE

The rotator cuff transverse force couple (RCTFC) is fundamental in the shoulder biomechanics, as the balance of its muscle components (the subscapularis relative to the infraspinatus and teres minor) provides stability to the joint. The chronic progression of rotator cuff tears usually present alterations in muscle volume, along with atrophy and compensatory hypertrophy, which can be determined using imaging techniques. The aim of this study was to quantify RCTFC muscle volume in a large sample taking into account the age and gender of the participants involved.

METHODS

An observational, retrospective, cross-sectional, descriptive and comparative study was conducted, evaluating thoracic computed tomography scans from 152 patients (304 shoulders) of indistinct gender, with ages ranging between 18 and 85 years. The RCTFC muscle volume was quantified with an oblique/multiplanar segmentation technique. Measuring time was also documented.

RESULTS

We observed that muscle volume decreases among the different age (p < 0.04) and gender (p < 0.001) groups. However, the RCTFC volume ratio remained constant at 1.02 ± 0.18 without significant differences throughout all age and gender groups evaluated (p > 0.298).

CONCLUSION

The decrease in the RCTFC muscle volume is proportional during the different stages of life, maintaining a constant ratio between its components (physiological RCTFC muscle atrophy). The time-saving segmentation method and volume ratio formula proposed in this study contribute to the management and understanding of rotator cuff tear/pathology.