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.

Serratus Anterior Fatigue Reduces Scapular Posterior Tilt and External Rotation During Arm Elevation.

CONTEXT: Fatigue of the scapular stabilizing muscles resulting from repeated arm motion has been reported to alter scapular kinematics, which could result in shoulder pathology, especially impingement. OBJECTIVE: This study aimed to examine the effects of fatigue of the serratus anterior muscle on scapular kinematics, specifically, decrease scapular posterior tilt and upward scapular rotation during arm elevation. DESIGN: Repeated measures. SETTING: Laboratory. PARTICIPANTS: Thirty participants were included in the investigation. INTERVENTIONS: Scapular kinematics and shoulder strength were measured before and immediately following a serratus anterior fatigue protocol. MAIN OUTCOME: Scapular 3-dimensional position during arm elevation. RESULTS: No difference in upward rotation of the scapula between prefatigue and postfatigue conditions (ascending: P = .188; descending: P = .798). Scapular posterior tilt decreased during arm elevation following the fatigue protocol between 60° and 90° and 90° and 120° of arm elevation during the ascent (P = .004) and the descent (P = .013). Fatigue by arm elevation angle interaction was found for clavicular elevation during the ascent (P = .050) between 90° and 120° of arm elevation. Scapular internal rotation increased during the ascent (P = .027). There was no difference in clavicular protraction between the prefatigue and postfatigue conditions (ascending: P ≤ .001; descending: P ≤ .001). CONCLUSION: Fatigue of the serratus anterior decreases posterior scapular tilt and greater clavicular elevation and scapular internal rotation at higher arm elevation angles. These findings are consistent with the scapular kinematic patterns associated with shoulder pain. Improving serratus anterior endurance might delay the changes in scapular kinematics associated with repeated arm motion and shoulder injury mechanisms.

Influential factors of subacromial impingement syndrome after hook plate fixation for acromioclavicular joint dislocation: A retrospective study.

ABSTRACT: Subacromial impingement syndrome (SIS) after hook plate fixation for acromioclavicular joint (AC) dislocation was the most common complication. However, the researches on its' influential factors were rare. The purpose of this study was to identify the risk factors by analyzing the influencing factors of postoperative SIS and minimize the incidence of SIS in clinical surgery.We retrospectively analyzed the prospectively collected data from 330 consecutive patients with AC joint dislocation between August 2014 and August 2017 at our institute. The SIS was presented as the dependent variable at the last follow-up when the internal fixation was removed. The independent variables included age, gender, body-mass index (BMI), smoking status, alcohol consumption, type of injury, Rockwood Classification, site of injury, operation time, injury-to-surgery, the distance between the hook body and the acromion (DBA), the depth of hook tip (DHT), the distance between the hook plate and the humeral head (DHH), the distance between the acromion and the humeral head (DAH), the hook plate angle (AHP) and acromial shape. Logistic regression analysis was performed to identify independent influential factors of SIS.A total of 312 cases were included and 18 cases were lost. The follow-up rate was 94.5%. In without SIS group, there were 225 cases (123 males and 102 females). In with SIS group, a total of 87 cases were included (56 males and 31 females). The incidence of SIS was 27.8%. DHT (OR = 9.385, 95% CI = 4.883 to 18.040, P < .001) and DBA (OR = 2.444, 95% CI = 1.591 to 3.755, P < .001) were the significant independent risk factor for SIS of AC dislocation treat with hook plate. DAH (OR = 0.597, 95% CI = 0.396 to 0.900, P = .014) and acromial shape with flat and straight (OR = 0.325, 95% CI = 0.135 to 0.785, P = .012) were also independent factors of SIS, but they were all protective.The SIS had a high incidence in fixation of clavicular hook plate for AC dislocation. DHT and DBA were two independent risk factors, DAH and acromial shape with flat and straight were two independent protective factors for SIS. In clinical surgery, we should avoid risk factors to reduce the incidence of SIS.

To explore the reasonable selection of clavicular hook plate to reduce the occurrence of subacromial impingement syndrome after operation.

BACKGROUND: Acromioclavicular joint dislocation is a shoulder joint injury common in the clinical setting and is generally surgically treated with clavicular hook plate technique with confirmed curative effect. However, symptoms such as shoulder abduction limitation, shoulder discomfort and joint pain postoperatively may occur in some patients. Therefore, this study aimed to explore whether the existing clavicular hook plate can be reasonably selected to reduce the incidence of subacromial impingement syndrome (SIS) and provide a reference for clinical diagnosis and treatment. MATERIALS AND METHODS: Patients with SIS admitted from March 2018 to June 2020 were selected as the experimental group and asymptomatic patients postoperatively, as the control group. The hook end depth and acromial height of the hook plate used in patients were recorded, and the difference between them was calculated. RESULTS: The difference between the hook plate depth and acromial height was 7.500±1.912 mm and 6.563±1.537 mm in the experimental and control groups, respectively, with statistically significant difference (t=3.021, P=0.006). A difference of >0.6 mm as a grouping index is required to perform a single factor analysis, with statistically significant difference (t=3.908, P=0.048). CONCLUSIONS: The occurrence of SIS after placing the clavicular hook plate may be related to the difference between its depth and the acromial height. A difference of >6 mm may be a factor affecting the occurrence of SIS. Pre-imaging measurement of the acromial height can provide suggestions for selecting the type of hook plate intraoperatively.

Scapular Notching After Reverse Total Shoulder Arthroplasty: Prediction Using Patient-Specific Osseous Anatomy, Implant Location, and Shoulder Motion.

BACKGROUND: Scapular notching is frequently observed following reverse total shoulder arthroplasty (rTSA), although the etiology is not well understood. METHODS: Twenty-nine patients with preoperative computed tomography (CT) scans who underwent rTSA with a Grammont design were evaluated after a minimum of 2 years of follow-up with video motion analysis (VMA), postoperative three-dimensional (3D) CT, and standard radiographs. The glenohumeral range of motion demonstrated by the VMA and the postoperative implant location on the CT were used in custom simulation software to determine areas of osseous impingement between the humeral implant and the scapula and their relationship to scapular notching on postoperative CT. Patients with and without notching were compared with one another by univariable and multivariable analyses to determine factors associated with notching. RESULTS: Seventeen patients (59%) had scapular notching, which was along the posteroinferior aspect of the scapular neck in all of them and along the anteroinferior aspect of the neck in 3 of them. Osseous impingement occurred in external rotation with the arm at the side in 16 of the 17 patients, in internal rotation with the arm at the side in 3, and in adduction in 12. The remaining 12 patients did not have notching or osseous impingement. Placing the glenosphere in a position that was more inferior (by a mean of 3.4 ± 2.3 mm) or lateral (by a mean of 6.2 ± 1.4 mm) would have avoided most impingement in the patients' given range of motion. Notching was associated with glenosphere placement that was insufficiently inferior (mean inferior translation, -0.3 ± 3.4 mm in the notching group versus 3.0 ± 2.9 mm in the no-notching group; p = 0.01) or posterior (mean, -0.3 ± 3.5 mm versus 4.2 ± 2.2 mm; p < 0.001). Two-variable models showed inferior and posterior (area under the curve [AUC], 0.887; p < 0.001), inferior and lateral (AUC, 0.892; p < 0.001), and posterior and lateral (AUC, 0.892; p < 0.001) glenosphere positions to be significant predictors of the ability to avoid scapular notching. CONCLUSIONS: Osseous impingement identified using patients' actual postoperative range of motion and implant position matched the location of scapular notching seen radiographically. Inferior, lateral, and posterior glenosphere positions are all important factors in the ability to avoid notching. Only small changes in implant position were needed to avoid impingement, suggesting that preoperative determination of the ideal implant position may be a helpful surgical planning tool to avoid notching when using this implant design. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Neutral glenoid alignment in reverse shoulder arthroplasty does not guarantee decreased risk of impingement.

Reverse Shoulder Arthroplasty (RSA) has gained popularity over the recent years, but impingement concerns are still present. Surgeons aim to correct pre-operative glenoid deformities to reduce impingement but it can be challenging without assistance like patient specific guides. However, it is unclear how accurate glenoid correction affects the impingement. The main objective of this study was to determine whether accurate glenoid correction to neutral version and tilt can reduce the risk of impingement. Two types of virtual surgeries were performed on 22 pre-operative arthritic shoulders: (i) "Interactive," the glenoid baseplate could be placed with accuracy, and (ii) "Blind," surgeons placed the RSA baseplate while they could only visualize the glenoid. The virtual models were then used in an RSA biomechanical model which recorded impingement for (i) four Range of Motion (ROM) tasks, (ii) ten Activities of Daily Living (ADL). The "Blind" method resulted in more variable glenoid placement (version and tilt) than the "Interactive" method (p = 0.001). However, both methods showed similar ROM and impingement occurrence in ADLs. The results suggest it is challenging for surgeons to accurately correct version and tilt on arthritic glenoids when only referencing off of the face of the glenoid. However, the variable glenosphere placement observed in the "Blind" method did not result in worse impingement compared to the accurate "Interactive" method. This was because both methods had similar inferior baseplate positioning which is more important than correcting version or tilt. Implantation accuracy remains important in RSA, but pre-operative planning should not just target at correcting version and tilt. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1213-1219, 2018.

The effect of glenoid component version and humeral polyethylene liner rotation on subluxation and impingement in reverse shoulder arthroplasty.

BACKGROUND: A previously validated finite element modeling approach was used to determine how changes in glenoid component version and polyethylene liner rotation within the humeral component affect the arm abduction angle at which impingement between the inferior glenoid and the polyethylene liner occurs as well as the amount of subluxation generated by that impingement. MATERIALS AND METHODS: Five glenoid component versions (5° anteversion; neutral; 5°, 10°, and 20° retroversion) and 7 polyethylene liner rotations (20° and 10° anterior; neutral; 10°, 20°, 30°, and 40° posterior) were considered, resulting in 35 different clinically representative models. The humerus was internally and externally rotated and extended and flexed, and the resulting impingement and subluxation were measured. To further analyze more global trends and to identify implantations least prone to subluxation, polyethylene liner rotation was additionally varied in coarser 30° increments across the entire 360° range. RESULTS: All subluxation caused by impingement occurred during external rotation and extension, and external rotation produced nearly 10-fold more subluxation than extension. Neutral glenoid component version was associated with the least amount of subluxation for all polyethylene liner rotations. Posteriorly rotated polyethylene liners, which place the thick inferior region of the component away from the scapula, produced the least amount of subluxation. The 90° and 120° posterior liner rotations produced no subluxation, whereas the 30° and 60° anterior liner rotations produced the greatest amount of subluxation. CONCLUSION: These results indicate that rotating modern radially asymmetric humeral polyethylene liners posteriorly can reduce the risk of subluxation leading to dislocation and increase external rotation range of motion.

Acute effects of scapular Kinesio Taping® on shoulder rotator strength, ROM and acromiohumeral distance in asymptomatic overhead athletes.

BACKGROUND: There is limited information in the literature that shows whether scapular taping has an effect on the acromiohumeral distance (AHD) and shoulder functions. The aim of this study was to investigate the acute effects of scapular Kinesio Taping® on shoulder internal rotation (IR) and external rotation (ER) strength, IR and ER range of motion (ROM) and AHD in asymptomatic overhead athletes. METHODS: Forty-one volleyball athletes (24 men, 17 women; mean age: 16.1±1.5 years, body mass: 66.5±9.6 kg, body height: 179.6±8.4 cm, Body Mass Index: 20.5±2.3 kg/m2, time participating in overhead sports activity: 6.2±1.4 h/week, experience in sport: 4.1±2.4 years) were included in this study. Shoulder IR and ER ROM, total rotation ROM, AHD, shoulder isometric IR and ER strength and ER:IR strength ratio of the dominant side were tested before and after taping. RESULTS: Scapular taping increased the shoulder IR (P<0.001) and total ROM (P<0.001), AHD (P<0.001), shoulder IR (P=0.002) and ER (P=0.006) strength. ER ROM and ER:IR ratio did not change after taping (P=0.26, P=0.98, respectively). CONCLUSIONS: The results of this study suggest that scapular taping could be an effective method for enhancing the acromiohumeral distance, shoulder rotator strength and range of motion. Therefore, scapular taping could be recommended for not only in the asymptomatic athletes' shoulder exercise training but also in the prevention of subacromial impingement syndrome.

Scapula kinematics of pull-up techniques: Avoiding impingement risk with training changes.

OBJECTIVES: Overhead athletic activities and scapula dyskinesia are linked with shoulder pathology; pull-ups are a common training method for some overhead sports. Different pull-up techniques exist: anecdotally some are easier to perform, and others linked to greater incidences of pathology. This study aims to quantify scapular kinematics and external forces for three pull-up techniques, thus discussing potential injury implications. DESIGN: An observational study was performed with eleven participants (age=26.8±2.4 years) who regularly perform pull-ups. METHODS: The upward motions of three pull-up techniques were analysed: palms facing anterior, palms facing posterior and wide-grip. A skin-fixed scapula tracking technique with attached retro-reflective markers was used. RESULTS: High intra-participant repeatability was observed: mean coefficients of multiple correlations of 0.87-1.00 in humerothoracic rotations and 0.77-0.90 for scapulothoracic rotations. Standard deviations of hand force was low: <5% body weight. Significantly different patterns of humerothoracic, scapulothoracic and glenohumeral kinematics were observed between the pull-up techniques. The reverse technique has extreme glenohumeral internal-external rotation and large deviation from the scapula plane. The wide technique has a reduced range of pro/retraction in the same HT plane of elevation and 90° of arm abduction with 45° external rotation was observed. All these factors suggest increased sub-acromial impingement risk. CONCLUSIONS: The scapula tracking technique showed high repeatability. High arm elevation during pull-ups reduces sub-acromial space and increases pressure, increasing the risk of impingement injury. Wide and reverse pull-ups demonstrate kinematics patterns linked with increased impingement risk. Weight-assisted front pull-ups require further investigation and could be recommended for weaker participants.

Combined effect of change in humeral neck-shaft angle and retroversion on shoulder range of motion in reverse total shoulder arthroplasty - A simulation study.

BACKGROUND: We studied combined effect of change in humeral neck shaft angle and retroversion on shoulder ROM in reverse total shoulder arthroplasty using 3-dimensional simulations. METHODS: Using a 3D model construct based on the CT scans of 3 males and a 3-dimensional analysis program, a humeral component of reverse total shoulder arthroplasty was implanted in 0°, 10°, 20°, 30°,40° retroversion and 135°, 145°, and 155° neck shaft angle. Total horizontal range of motion (sum of horizontal adduction and abduction) at 30° and 60° scaption, adduction in the scapular plane and IR behind the back were measured for various combinations of neck shaft angle and retroversion. FINDINGS: Change in retroversion didn't show any effect on total horizontal range of motion. Total horizontal range of motion at both 30° and 60° scaption, showed maximum values at 135° neck shaft angle and minimum values at 155° neck shaft angle. With any combination of retroversion angles, adduction deficit was maximum at 155° neck shaft angle and no adduction deficit at 135° neck shaft angle. Every 10° decrease in neck shaft angle resulted in an average 10.4° increase in adduction. For every 10° increase in retroversion, there was loss of internal rotation behind the back up to at least one vertebral level. INTERPRETATION: 135° neck shaft angle resulted in maximum total horizontal range of motion both at 30° and 60° scaption regardless of retroversion angles. 135° neck shaft angle also reduced the chances of scapular impingement. Decrease in retroversion angle resulted in more amount of internal rotation behind the back.

A comparison of concentric and eccentric glenospheres in reverse shoulder arthroplasty: a randomized controlled trial.

BACKGROUND: Inferior scapular notching following reverse shoulder arthroplasty is due to mechanical impingement and, in some studies, has been associated with poorer functional scores, lower patient satisfaction, and more limited shoulder motion. We aimed to test the hypothesis that inferior positioning of the center of rotation with eccentric glenosphere designs decreases the adduction deficit before impingement occurs and improves clinical outcome. METHODS: A randomized, controlled, double-blinded trial was performed. According to the results of a power analysis, fifty patients undergoing reverse shoulder arthroplasty for the diagnosis of cuff tear arthropathy were randomized intraoperatively to receive either a concentric or eccentric glenosphere. The glenoid baseplate was positioned flush to the inferior border of the glenoid before the glenosphere was then attached. Notching was assessed using an anteroposterior radiograph, and clinical outcome was assessed using the visual analog pain scale score, shoulder function rating, American Shoulder and Elbow Surgeons score, and Oxford shoulder score. Active forward elevation and external rotation were assessed. The outcome assessor was blinded to the treatment group. The mean follow-up period for the groups was forty-three and forty-seven months. RESULTS: Patient demographics and preoperative scores were similar between the groups. At the time of the final follow-up, four patients (14.8%) in the concentric group had developed inferior scapular notching (two with Nerot grade I and two with Nerot grade II), ranging in size from 1.1 to 7.4 mm, compared with one patient (4.3%; Nerot grade I) in the eccentric group (p = 0.36). No notching occurred in any patient with glenoid overhang of >3.5 mm. No significant difference between the groups was seen with respect to functional outcome scores, patient satisfaction, or shoulder motion. CONCLUSIONS: There were no differences in notching rates or clinical outcomes between concentric and eccentric glenospheres following reverse shoulder arthroplasty. Inferior glenosphere overhang of >3.5 mm, however, prevented notching. This may be achieved with a modified surgical technique, but eccentric glenospheres provide an additional option. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Effect of scapular pillar anatomy on scapular impingement in adduction and rotation after reverse shoulder arthroplasty.

BACKGROUND: Notching of the scapular pillar is the main radiographic complication seen during follow-up of reverse shoulder arthroplasties. Several recommendations pertaining to the implantation technique and glenoid component design have been suggested. No studies have investigated potential anatomic risk factors for inferior scapular impingement. HYPOTHESIS: A specific anatomic shape of the scapular pillar promotes the development of notching. MATERIALS AND METHODS: The Aequalis Reversed(®) (Tornier Inc., Edina, MN, USA) prosthesis was implanted into 40 cadaver scapulae. We measured maximal range-of-motion (ROM) in internal rotation, external rotation, and adduction. The anatomic specimens were then imaged using two-dimensional computed tomography (CT) and the scapular neck angle, surface area under the scapular pillar, and distance from the central glenosphere peg to the inferior glenoid rim were measured. Associations between these CT parameters and ROM values were assessed using statistical independence tests. RESULTS: ROM values were greatest when the surface area under the scapular pillar was above 0.8 cm(2) (P<0.5). This feature combined with a scapular neck angle less than 105° produced the largest ROM values (P<0.5). DISCUSSION: The scapular neck angle alone is not sufficient to identify a scapular morphology that increases the risk of notching. The surface area under the scapular pillar, in contrast, discriminates between scapulae with and without a high risk of notching. The surface area under the scapular pillar is influenced by the inferior glenoid offset. CONCLUSION: We were unable to define a specific scapular shape at high risk for notching. The prevention of notching should rely chiefly on a rigorous glenoid component implantation technique, with particular attention to the inferior offset. LEVEL OF EVIDENCE: III, experimental study.

[Morbidity of neck dissection submuscular recess (sublevel IIb) in head and neck cancer]. / Morbidité des curages ganglionnaires cervicaux en cancérologie ORL (secteur IIb).

OBJECTIVES: The impact of neck dissection on quality of life has often been considered less important than the oncological control. Dissection of level IIb doesn't improve oncologic control everytime, knowing that an injury of the spinal nerve can occur. The aim of our study was to assess the impact of neck dissection including level IIb on shoulder function and quality of life in N0 patients. MATERIALS AND METHODS: Fifteen patients with squamous cell carcinoma of the upper aerodigestive tract, clinical and radiological NO, were included. They were assessed by validated scales (QLQ-C30, H&N35 and DASH) and they underwent an examination of the shoulder. RESULTS: Almost half of the patients had pain in the shoulder. The functional scale score QLQ-C30 was statistically more altered (49.7%) than that of patients with cancer in general (74.9%, p = 0.00016) and of the general population 60 to 69 years (85.4%, p = 0). CONCLUSION: The results of our study underscore the morbidity on shoulder function after neck dissection. These findings, combined with the low prevalence of occult lymph node metastases in level IIb among T1-T2 patients, must question the systematic inclusion of this level in neck dissection.

Scapular kinematics and shoulder elevation in a traditional push-up.

CONTEXT: Proper scapulothoracic motion is critical for the health and function of the shoulder and represents a principal focus in the rehabilitation setting. Variants of the traditional push-up are used frequently to help restore proper scapular kinematics. To date, substantial research has focused on muscle activation levels of rotator cuff and scapular-stabilizing musculature, whereas a dearth of literature exists regarding scapular kinematics during push-up variants. OBJECTIVE: To examine the effect of shoulder position on scapular kinematics across the range of motion (ROM) of a traditional push-up. DESIGN: Cross-sectional study. SETTING: University laboratory. PATIENTS OR OTHER PARTICIPANTS: Sixteen healthy participants without a history of upper extremity or spine injury requiring rehabilitation or surgery. INTERVENTION(S): Participants performed a traditional push-up while kinematic measurements were acquired from multiple upper extremity segments. The 3 shoulder position conditions were (1) self-selected position, (2) shoulder adducted upon ascent (at side), and (3) shoulder elevated to approximately 90°. MAIN OUTCOME MEASURE(S): Scapular posterior tilt, upward rotation, and external rotation were examined across elbow-extension ROM and compared across conditions. RESULTS: Posterior tilt was greater in the self-selected and at-side conditions than in the elevated condition and increased linearly with elbow extension. External rotation was greater in the self-selected and at-side conditions compared with that in the elevated condition. In the at-side condition, upward rotation began lower than in the other conditions at the start of the concentric phase but increased above the others soon after the elbow started to extend. CONCLUSIONS: Performing a traditional push-up with the shoulders elevated may place the scapula in a position of impingement. Clinicians should be cognizant of shoulder elevation when prescribing and monitoring exercise progression. The results of this study will provide further direction for clinicians in prescribing rehabilitation exercises for the upper extremity, especially closed chain exercises for shoulder conditions.

Activities of daily living with reverse prostheses: importance of scapular compensation for functional mobility of the shoulder.

HYPOTHESIS: The nonanatomical design of reverse shoulder prostheses induce medial displacement of the center of rotation, impingements and may reduce the mobility of the shoulder. The aim of this study is to test the hypothesis that during activities of daily living functional mobility of the shoulder can be restored by scapular compensation. MATERIAL AND METHODS: A numerical 3-dimensional model was developed to reproduce the movement of the scapula and humerus, during 4 activities of daily living measured experimentally. This hypothesis was tested in 4 configurations of the aequalis reverse prosthesis (standard 36-mm glenosphere, 42-mm glenosphere, lateralized 36-mm glenosphere, lateralized Bony Increased-Offset Reverse Shoulder Arthroplasty [BIO-RSA]), which were implanted in the virtual model. All impingement positions were evaluated, as the required scapular compensation to avoid impingements. RESULTS: With the 36-mm glenosphere, impingements occurred only for rest of hand to back-pocket positions. The 42-mm partly improved the mobility. The 2 lateralized glenospheres were free of impingement. When impingements occurred, the scapular compensation was less than 10°. CONCLUSION: Most reverse prostheses impingements reported in clinical and biomechanical studies can be avoided, either by scapular compensation or by a glenosphere lateralization. After reverse shoulder arthroplasty, a fraction of the mobility of the gleno-humeral is transferred to the scapulo-thoracic joint.

Effects of glenosphere positioning on impingement-free internal and external rotation after reverse total shoulder arthroplasty.

INTRODUCTION: Patients may experience a loss of internal rotation (IR) and external rotation (ER) after reverse total shoulder arthroplasty (RTSA). We hypothesized that alterations in the glenosphere position will affect the amount of impingement-free IR and ER. MATERIALS AND METHODS: Computed tomography (CT) scans of the scapula and humerus were obtained from 7 cadaveric specimens, and 3-dimensional reconstructions were created. RTSA models were virtually implanted into each specimen. The glenosphere position was determined in relation to the neutral position in 7 settings: medialization (5 mm), lateralization (10 mm), superior translation (6 mm), inferior translation (6 mm), superior tilt (20°), and inferior tilt (15° and 30°). The humerus in each virtual model was allowed to freely rotate at a fixed scaption angle (0°, 20°, 40°, and 60°) until encountering bone-to-bone or bone-to-implant impingement (180° of limitation). Measurements were recorded for each scaption angulation. RESULTS: At 0° scaption, only inferior translation, lateralization, and inferior tilt (30°) allowed any impingement-free motion in IR and ER. At the midranges of scaption (20° and 40°), increased lateralization and inferior translation resulted in improved rotation. Supraphysiologic motion (>90° rotation) was seen consistently at 60° of scaption in IR. Superior translation (6 mm) resulted in no rotation at 0° and 20° of scaption for IR and ER. CONCLUSIONS: Glenosphere position significantly affected humeral IR and ER after RTSA. Superior translation resulted in significant restrictions on IR and ER. Optimal glenosphere positioning was achieved with inferior translation, inferior tilt, and lateralization in all degrees of scaption.

[Rotator cuff plasty with the suture bridge technique]. / Plastía de manguito rotador con técnica de sutura puente bridge.

OBJECTIVE: To assess the clinical results and integrity of arthroscopic repair of rotator cuff tears using the suture bridge technique. MATERIAL AND METHODS: Fifty-six shoulders with total thickness rotator cuff tears were assessed. Mean follow-up was 19 months. Repair integrity was analyzed postoperatively with imaging and recovery times. RESULTS: The University of California at Los Angeles scale was used during the followup; the preoperative mean improved from 13.2 points to 29.7 (p\001). The rotator cuff healed completely in 66.7 of the 56 shoulders. The incidence of fatty regeneration of rotator cuff muscles was more common in individuals > 60 years of age (p = 0.002). The latter had a higher chance of recurrent tear (p\001). DISCUSSION: There was significant pain relief in the visual analogue scale and improvement in ranges of motion. The advantages of this technique include that it allows immobilizing with a sling without the need for maximum abduction protection; it is a safer repair due to the configuration of the double band intercrossed over the tendon that provides greater fixation and stability, with greater coverage of the tear defect.

The use of a vertical arm support device to reduce upper extremity muscle firing in sonographers.

Work-related musculoskeletal disorders (WRMSD) in sonographers have increased over the past 20 years with shoulder injuries being the most prevalent. Advancing ultrasound technologies have reduced a sonographer's need to move when performing exams and increased prolonged arm abduction, resulting in static work postures and decreased joint perfusion. Work modifications in other industries have demonstrated that reducing arm abduction to 30° reduces muscle firing and fatigue. Although this is the ideal work posture for sonographers, there are many instances in which excessive arm abduction and static postures cannot be avoided. These positions are further complicated by the fact that the scanning arm is also supporting the weight of the ultrasound transducer. This observational case study evaluated the use of a moveable arm support system as a means to provide support for the scanning arm and reduce muscle firing during ultrasound exams in the scanning lab of a university diagnostic ultrasound educational program.

Effect of humeral component version on impingement in reverse total shoulder arthroplasty.

HYPOTHESIS: Reverse shoulder arthroplasty is growing in popularity for patients with deficient rotator cuffs; however, the phenomenon of scapular notching continues to be a concern. This study examined the effects of humeral component version in the Aequalis Reversed Shoulder Prosthesis (Tornier, Edina, MN) on impingement of the humeral prosthesis against the scapula to test the hypothesis that the mechanical contact of the humeral component with the scapular neck is influenced by the version of the humeral component. MATERIALS AND METHODS: Seven shoulders from deceased donors were tested after the Aequalis Reversed Shoulder was implanted. The deltoid, pectoralis major, and latissimus dorsi were loaded based on physiologic cross-sectional area. The degree of internal and external rotation when impingement, subluxation, or dislocation occurred was measured at 0°, 30°, and 60° glenohumeral abduction in the scapular plane. Testing was performed with the humeral component placed in 20° of anteversion, neutral version, 20° of retroversion, and 40° of retroversion. RESULTS: Maximum external rotation at 0° abduction was -1° ± 4° at 20° anteversion, 15° ± 3° at neutral, 28° ± 4° at 20° retroversion, and 44° ± 5° at 40° retroversion (P < .05). Maximum internal rotation at 0° abduction was 128° ± 9° at 20° anteversion, 112° ± 9° at neutral, 99° ± 8° at 20° retroversion, and 83° ± 8° at 40° retroversion (P < .05). Maximum external rotation at 30° abduction was 70° ± 6° at 20° anteversion, 84° ± 7° at neutral, 97° ± 6° at 20° retroversion, and 110° ± 5° at 40° retroversion (P < .05). There was no limitation to internal rotation at 30° abduction. No impingement occurred at 60° abduction. DISCUSSION: Version of the humeral component plays a role in range of motion and impingement in reverse total shoulder arthroplasty. Anteversion can significantly decrease the amount of external rotation achievable after reverse total shoulder surgery. CONCLUSION: Placing the Aequalis Reversed Shoulder humeral component at between 20° and 40° of retroversion more closely restores a functional arc of motion without impingement.