Effects of asymptomatic rotator cuff pathology on in vivo shoulder motion and clinical outcomes

Test-retest reliability of isometric shoulder muscle strength during abduction and rotation tasks measured using the Biodex dynamometer

BACKGROUND

The Constant score (CS) is often used clinically to assess shoulder function and includes a muscle strength assessment only for abduction. The aim of this study was to evaluate the test-retest reliability of isometric shoulder muscle strength during various positions of abduction and rotation with the Biodex dynamometer and to determine their correlation with the strength assessment of the CS.

METHODS

Ten young healthy subjects participated in this study. Isometric shoulder muscle strength was measured during 3 repetitions for abduction at 10° and 30° abduction in the scapular plane (with extended elbow and hand in neutral position) and for internal and external rotation (with the arm at 15° abduction in the scapular plane and elbow flexed at 90°). Muscle strength tests with the Biodex dynamometer were measured in 2 different sessions. The CS was acquired only in the first session. Intraclass correlation coefficients (ICCs) with 95% confidence interval, limits of agreement, and paired t tests for repeated tests of each abduction and rotation task were calculated. Pearson's correlation between the strength parameter of the CS and isometric muscle strength was investigated.

RESULTS

Muscle strength did not differ between tests (P > .05) with good to very good reliabilities for abduction at 10° and 30°, external rotation and internal rotation (ICC >0.7 for all). A moderate correlation of the strength parameter of the CS with all isometric shoulder strength parameters was observed (r > 0.5 for all).

CONCLUSION

Shoulder muscle strength for abduction and rotation measured with the Biodex dynamometer are reproducible and correlate with the strength assessment of the CS. Therefore, these isometric muscle strength tests can be further employed to investigate the effect of different shoulder joint pathology on muscle strength. These measurements consider a more comprehensive functionality of the rotator cuff than the single strength evaluation in abduction within the CS as both abduction and rotation are assessed. Potentially, this would allow for a more precise differentiation between the various outcomes of rotator cuff tears.

Arthroscopic Rotator Cuff Repair with and without Acromioplasty in the Treatment of Full-Thickness Rotator Cuff Tears: Long-Term Outcomes of a Multicenter, Randomized Controlled Trial

BACKGROUND

The aim of this study was to reevaluate patients from a previous randomized controlled trial at a long-term follow-up to determine the long-term efficacy of subacromial decompression in patients with full-thickness rotator cuff tears.

METHODS

This is a secondary study based on a previous, multicenter, randomized controlled trial with patients allocated to arthroscopic rotator cuff repair with or without acromioplasty. The original study was conducted between 2003 and 2011, and the secondary study was conducted between 2015 and 2021. Patients were invited by a blinded assessor to return to complete the Western Ontario Rotator Cuff (WORC) index and a questionnaire about reoperation and to undergo a clinical assessment. If participants were unable to return, they were asked to complete the questionnaires by mail. A chart review on all participants in the original study was conducted.

RESULTS

Eighty-six patients were randomized in the original trial, with 31 of 45 from the group without acromioplasty and 25 of 41 from the acromioplasty group returning for long-term follow-up. The mean duration (and standard deviation) of follow-up was 11.2 ± 2.4 years for the group without acromioplasty and 11.5 ± 2.6 years for the acromioplasty group. There was no significant difference in WORC scores between the groups with and without acromioplasty at the time of the long-term follow-up (p = 0.30). Seven (16%) of the 45 patients in the group without acromioplasty underwent reoperation. One (2%) of the initial 41 patients allocated to acromioplasty underwent reoperation. All patients who underwent a reoperation had a Type-2 or 3 acromion.

CONCLUSIONS

Patients who underwent rotator cuff repair with or without acromioplasty experienced improvement of outcomes from their preoperative level at a long-term follow-up (mean, 11 years), and there were no differences in patient-reported outcomes, specifically WORC scores, between these groups. However, a significantly higher reoperation rate was observed in patients who had rotator cuff repair without acromioplasty, specifically in those with a Type-2 or 3 acromion.

LEVEL OF EVIDENCE

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

Associations between range of motion, strength, tear size, patient-reported outcomes, and glenohumeral kinematics in individuals with symptomatic isolated supraspinatus tears

BACKGROUND

Clinical failure associated with nonoperative treatment of rotator cuff tears may be due to inadequate characterization of the individual's functional impairments. Clinically, restricted passive range of motion (ROM) (restrictions imply capsular tightness), limitations in muscle strength, and larger rotator cuff tears are hypothesized to be related to altered glenohumeral kinematics. Understanding these relationships, as well as the relationship between glenohumeral kinematics and patient-reported outcomes (PROs) prior to exercise therapy, may help characterize functional impairments in individuals with rotator cuff tears. The objectives of the study were to describe the baseline presentation of individuals with an isolated supraspinatus tear, including passive ROM, rotator cuff muscle strength, tear size, PROs, and glenohumeral kinematics, and to determine associations among these variables.

METHODS

One hundred one individuals with symptomatic isolated supraspinatus tears were recruited for the study and underwent assessments of passive glenohumeral ROM, isometric muscle strength, and ultrasonography to assess anterior-posterior tear size. Glenohumeral kinematics during scapular-plane abduction were measured using biplane radiography. Furthermore, PROs including the American Shoulder and Elbow Surgeons (ASES) score and the Western Ontario Rotator Cuff Index (WORC) score were collected.

RESULTS

Individuals presented with decreased ROM, external rotation weakness compared with the uninvolved side, and pain and disability as measured by the ASES and WORC scores. These findings were not associated with glenohumeral kinematics, with the exception of a weak positive association between glenohumeral contact path lengths and WORC scores (ρ = 0.25, P = .03). Tear size was 11.7 ± 5.7 mm, and maximum anterior translation, superior translation, and contact path length were 3.0% ± 3.8% of glenoid width, 3.5% ± 3.8% of glenoid height, and 38.2% ± 20.7% of glenoid size, respectively.

CONCLUSION

Individuals with a symptomatic isolated supraspinatus tear presented with decreased ROM, external rotation weakness, and pain and disability as measured by the ASES and WORC scores. However, no abnormal kinematics associated with these limitations were observed. Thus, given that the tear is isolated to the supraspinatus tendon and no capsular restrictions are present, normal function of the glenohumeral joint may be possible during scapular-plane abduction.

Functional results after oncological scapula resections

INTRODUCTION

Tumors of the scapula are rare representing only 1.6%-2.8% of all skeletal tumor localizations. Wide resection of these tumors is often necessary, and their anatomic location is the most decisive factor for the extent of the resection. Because of the importance of the shoulder girdle for all daily activities, such resections can have major functional consequences. However, only few reports with small numbers of cases are found in the literature.

PATIENTS AND METHODS

We retrospectively evaluated 31 consecutive patients with scapular tumors treated surgically for aggressive benign or malignant tumors of the scapula. Patients who had received curettage only were excluded. Four of these 31 patients were lost to follow-up. In 7 of the remaining 27 patients, a total scapulectomy had to be performed, whereas all others received a partial resection. In 1 case, a partial resection and replantation after irradiation was performed. Musculoskeletal Tumor Society Scoring System (MSTS) and Toronto Extremity Salvage Score (TESS) scores were evaluated postoperatively at the time of their follow-up.

RESULTS

In 16 men and 11 women, the median age was 46.2 years and the tumor entities were heterogeneous. The median follow-up time was 71 months. Three patients died during follow-up due to their tumor and 1 due to cardiac disease. We found significantly better functional results in the group with incomplete scapula resections as opposed to the scapulectomy group. We did not see a significant functional difference between the patients with benign and those with malignant lesions. Both the MSTS score with median 83.3% (range between 23% and 100%) and the TESS score with 81.6% (ranging from 20.4% to 100%) were at a satisfactory level. The preservation of the supraspinatus muscle was shown to be advantageous for better shoulder function, and younger patients also tended to have better postoperative results.

CONCLUSION

The resection of scapular tumors may lead to a significant functional disability of the shoulder girdle and the affected arm in many cases. However, this is represented neither in the MSTS or TESS score nor in the overall acceptance of the patients. Only 1 patient, an artisan, had to change his job. In total, the clinical results are quite good in short- and long-term follow-up. The score results were comparable to other studies.

Association between type of rotator cuff tear and functional outcomes in patients with massive and irreparable rotator cuff tear: A pre-post intervention study

BACKGROUND

The aim of this study was to analyze: (1) the differences in the pre-post change in functional outcomes after a physical therapy program by the type of massive and irreparable rotator cuff tear (MIRCT) controlling for potential confounders, and (2) the influence of lifestyle behaviors and demographic and tear tendon characteristics on function in patients over 60 years of age with conservatively treated MIRCT.

MATERIALS AND METHODS

In this pre-post intervention study, 92 patients were prospectively recruited at the Clinical Hospital San Borja Arriaran, with atraumatic MIRCT, between 60 and 75 years of age (mean: 67.9 ± 4.5 years), and the mean of length of symptoms was 16.5 months (±5.7 months). Patients received a physical therapy program consisting of manual therapy and a specific exercise program of 2 sessions per week for 12 weeks. The imaging findings were performed by 2 medical radiologists who classified the rotator cuff tear according to the criteria proposed by Collins. Shoulder function, upper limb function, and pain intensity were assessed with the Constant-Murley; Disabilities of the Arm, Shoulder, and Hand; and visual analog scale (VAS), respectively. Analysis of covariance models were estimated to assess differences in MIRCT categories between functional outcomes. Multiple regression model analysis was used for the association between the change in functional outcomes and lifestyle behaviors, and demographic and tear tendon characteristics.

RESULTS

The results showed no pre-post change in functional outcomes by type of MIRCT in all models (P > .05). There is an association between length of symptoms (P = .000), and the baseline values of the 3 functional measures (P = .000) are associated with changes in Constant-Murley; Disabilities of the Arm, Shoulder, and Hand; and VAS. In addition, changes in VAS are associated with body mass index (BMI) (P = .000), and changes in Constant-Murley are associated with gender (P = .023), BMI (P = .000), and tobacco consumption (P = .000).

CONCLUSION

There is no difference in functional outcomes by type of MIRCT after a physical therapy program controlling for potential confounders. In addition, there is an association of length of symptoms with all functional outcomes, an association of BMI with VAS and Constant-Murley questionnaire, and an association between tobacco consumption and Constant-Murley questionnaire. Our results could influence the orthopedic surgeon's decisions; thus, not predicting the functional outcome through imaging findings could lead clinicians to reconsider the need for surgery in the treatment algorithm in patients over 60 years with MIRCT. In addition, demographic characteristics and lifestyle behaviors might be considered within the patient's evaluation and follow-up to decide on surgical interventions and evaluate the clinical course of the disease. Further studies measuring additional variables and longer follow-up are needed to confirm these results.

Measuring 3D In-vivo Shoulder Kinematics using Biplanar Videoradiography

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, multiple ligaments, and approximately 20 muscles. Unfortunately, shoulder pathologies (e.g., rotator cuff tears, joint dislocations, arthritis) are common, resulting in substantial pain, disability, and decreased quality of life. The specific etiology for many of these pathologic conditions is not fully understood, but it is generally accepted that shoulder pathology is often associated with altered joint motion. Unfortunately, measuring shoulder motion with the necessary level of accuracy to investigate motion-based hypotheses is not trivial. However, radiographic-based motion measurement techniques have provided the advancement necessary to investigate motion-based hypotheses and provide a mechanistic understanding of shoulder function. Thus, the purpose of this article is to describe the approaches for measuring shoulder motion using a custom biplanar videoradiography system. The specific objectives of this article are to describe the protocols to acquire biplanar videoradiographic images of the shoulder complex, acquire CT scans, develop 3D bone models, locate anatomical landmarks, track the position and orientation of the humerus, scapula, and torso from the biplanar radiographic images, and calculate the kinematic outcome measures. In addition, the article will describe special considerations unique to the shoulder when measuring joint kinematics using this approach.

Comparison of shoulder muscle strength, cross-sectional area, acromiohumeral distance, and thickness of the supraspinatus tendon between symptomatic and asymptomatic patients with rotator cuff tears

BACKGROUND

The purpose of this study was to demonstrate the differences in shoulder muscle strength, cross-sectional area of the rotator cuff muscles, acromiohumeral distance, and supraspinatus tendon thickness between symptomatic and asymptomatic patients with rotator cuff tears.

METHODS

Thirty-two symptomatic patients and 23 asymptomatic patients with rotator cuff tears participated in this study. Data of the patients with any type of tear and supraspinatus tear were analyzed. We evaluated the isometric torque, cross-sectional area of the rotator cuff muscles, supraspinatus tendon thickness, acromiohumeral distance, range of motion, and Western Ontario Rotator Cuff Index.

RESULTS

Asymptomatic patients showed greater isometric torque of shoulder abduction and internal rotation than symptomatic patients with any type of tear (P ≤ .01). Asymptomatic patients also demonstrated greater cross-sectional area of the supraspinatus (P < .01); however, there was no significant difference in the cross-sectional area of the other cuff muscles. There was also no significant difference in the supraspinatus tendon thickness (P = .10). The acromiohumeral distance at 90° of shoulder abduction was larger (P = .04) in asymptomatic patients. Additionally, similar tendencies were observed in the results of patients with supraspinatus tears, except for the isometric torque of shoulder external rotation. This torque was greater (P < .01) in asymptomatic patients.

CONCLUSION

Asymptomatic patients showed greater shoulder range of motion, muscle strength of shoulder abduction and internal rotation, small occupation ratio of supraspinatus tendon thickness as a percentage of acromiohumeral distance, and large cross-sectional area of supraspinatus.

Instantaneous helical axis estimation of glenohumeral kinematics: The impact of rotator cuff pathology

The rotator cuff is theorized to contribute to force couples required to produce glenohumeral kinematics. Impairment in these force couples would theoretically result in impaired ball-and-socket kinematics. Although less frequently used than traditional kinematic descriptors (e.g., Euler angles, joint translations), helical axes are capable of identifying alterations in ball-and-socket kinematics by quantifying the variability (i.e., dispersion) in axis orientation and position during motion. Consequently, assessing glenohumeral helical dispersion may provide indirect evidence of rotator cuff function. The purpose of this exploratory study was to determine the extent to which rotator cuff pathology is associated with alterations in ball-and-socket kinematics. Fifty-one participants were classified into one of five groups based on an assessment of the supraspinatus using diagnostic imaging: asymptomatic healthy, asymptomatic tendinosis, asymptomatic partial-thickness tear, asymptomatic full-thickness tear, symptomatic full-thickness tear. Glenohumeral kinematics were quantified during coronal plane abduction using a biplane x-ray system and described using instantaneous helical axes. The degree to which glenohumeral motion coincided with ball-and-socket kinematics was described using the angular and positional dispersion about the optimal helical axis and pivot, respectively. No statistically significant difference was observed between groups in angular dispersion. However, symptomatic individuals with a full-thickness supraspinatus tear had significantly more positional dispersion than asymptomatic individuals with a healthy supraspinatus or tendinosis. These findings suggest that symptomatic individuals with a full-thickness supraspinatus tear exhibit impaired ball-and-socket kinematics, which is believed to be associated with a disruption of the glenohumeral force couples.

Rotator Cuff Tear Susceptibility Is Associated With Variants in Genes Involved in Tendon Extracellular Matrix Homeostasis

Rotator cuff tears (RCT) is a multifactorial disease with genetic factors contributing for the disease etiology. We hypothesized that genetic variants in genes involved in extracellular matrix (ECM) homeostasis may alter susceptibility to RCT. We evaluated 20 polymorphisms of genes involved in ECM homeostasis in 211 cases of full-thickness tears of the supraspinatus (N_females  = 130; N_males  = 81) and 567 age-matched controls (N_females  = 317; N_males  = 250). Multivariate logistic regressions were carried out with age, gender, genetic ancestry (based on the analysis of 61 biallelic short insertion/deletion polymorphisms), and common co-morbidities (diabetes, dyslipidemia, and smoking habits) as covariates. We observed that carriers of the rare allele of both studied variants of TGFB1, as well as their G/A (rs1800470/rs1800469) haplotype, were less susceptible to RCT (p < 0.05). In contrast, carriers of the G allele of MMP9 rs17576 (p = 0.014) or G/G haplotype (rs17576/rs17577; p < 0.001) had an increased risk for tendon tears. The presence of the T allele of MMP2 rs2285053 (p = 0.033), the T allele of MMP3 rs679620 (p = 0.024), and the TT-genotype of TIMP2 rs2277698 (p = 0.01) was associated with susceptibility to tears, especially in females. In males, the A allele of COL5A1 rs3196378 (p = 0.032) and the G allele of TGFBR1 rs1590 (p = 0.039) were independent risk factors for RCT. The C/T COL5A1 (rs3196378/rs11103544) haplotype was associated with a reduced risk of tears in males (p = 0.03). In conclusion, we identified the genetic variants associated with RCT susceptibility, thereby reinforcing the role of genes involved in the structure and homeostasis of the ECM of tendons in disease development. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:192-201, 2020.

Shoulder kinematics impact subacromial proximities: a review of the literature

BACKGROUND

Alterations in glenohumeral and scapulothoracic kinematics have been theorized to contribute to rotator cuff pathology by impacting the magnitude of the subacromial space.

OBJECTIVE

The purpose of this review is to summarize what is currently known about the relationship between shoulder kinematics and subacromial proximities.

CONCLUSIONS

A variety of methods have been used to quantify subacromial proximities including photographs, MR imaging, ultrasonography, and single- and bi-plane radiographs. Changes in glenohumeral and scapulothoracic kinematics are associated with changes in subacromial proximities. However, the magnitude and direction of a particular motion's impact on subacromial proximities often vary between studies, which likely reflects different methodologies and subject populations. Glenohumeral elevation angle has been consistently found to impact subacromial proximities. Plane of humeral elevation also impacts subacromial proximities but to a lesser degree than the elevation angle. The impact of decreased scapulothoracic upward rotation on subacromial proximities is not absolute, but instead depends on the angle of humerothoracic elevation. The effects of scapular dyskinesis and humeral and scapular axial rotations on subacromial proximities are less clear. Future research is needed to further investigate the relationship between kinematics and subacromial proximities using more homogenous groups, determine the extent to which compression and other factors contribute to rotator cuff pathology, and develop accurate and reliable clinical measures of shoulder motion.

Asymptomatic Rotator Cuff Tears

Asymptomatic rotator cuff tears (RCTs) are prevalent in the general population; they are positively associated with age and are common in the contralateral shoulder of individuals who are being treated for shoulder pain or a symptomatic RCT. Asymptomatic RCTs are likely to become symptomatic over time, corresponding with decreased patient-reported function, strength, and range of motion. Previous studies have largely reported inconsistent findings regarding patient-reported outcomes, strength, range of motion, and kinematics in individuals with asymptomatic RCTs. Future research would benefit from characterizing any functional alteration that is associated with asymptomatic rotator cuff pathology, including determining whether such alterations are detrimental or compensatory and understanding the mechanism by which an asymptomatic RCT becomes symptomatic.

In vivo dynamic acromiohumeral distance in shoulders with rotator cuff tears

BACKGROUND

There are no previous studies on the acromiohumeral distance in shoulders with large-to-massive full-thickness rotator cuff tears. In this study, the acromiohumeral distance in rotator cuff tear and healthy shoulders was measured using 3D-to-2D model-to-image registration techniques.

METHODS

The dynamic glenohumeral kinematics during scapular plane abduction and axial rotation were analyzed in 11 rotator cuff tear patients and 10 healthy control subjects. Periodic radiographic images of scapular plane abduction and axial rotation were taken using a flat-panel radiograph image detector. Movements of the shoulder joint were assessed using radiographic images and computed tomography-derived digitally reconstructed radiographs. The acromiohumeral distance was defined as the shortest 3D distance between the acromion and the proximal humerus.

FINDINGS

For scapular plane abduction, the rotator cuff tear group had significantly smaller acromiohumeral distance than the control group at 15°, 30°, 45°, 60°, 75°, 135°, and 150° of humeral abduction (P < 0.05 at each measured angle). For axial rotation in the adducted position, the rotator cuff tear group had significantly smaller acromiohumeral distance than the control group at each point between -20° and 40° of glenohumeral external rotation (P < 0.05 at each measured angle).

INTERPRETATION

The minimum measured acromiohumeral distance was 0.9 mm in the rotator cuff tear shoulders and 2.1 mm in the healthy shoulders at 90° of scapular plane abduction. The findings are of clinical relevance because quantitative evaluation of the dynamic acromiohumeral distances in rotator cuff tear and healthy shoulders might provide important insight into subacromial impingement.