The function of the upper extremity is highly dependent on correlated motion of the shoulder. The shoulder can be affected by several diseases. The most common are: rotator cuff tear (RCT), shoulder instability, shoulder osteoarthritis and fractures. Rotator cuff disease is a common disorder. It has a high prevalence rate, causing high direct and indirect costs. The appropriate treatment for RCT is debated. The American Academy Orthopaedic Surgeons guidelines state that surgical repair is an option for patients with chronic, symptomatic full-thickness RCT, but the quality of evidence is unconvincing. Thus, the AAOS recommendations are inconclusive. We are performing a randomized controlled trial to compare surgical and conservative treatment of RCT, in term of functional outcomes, rotator cuff integrity, muscle atrophy and fatty degeneration. Shoulder instability occurs when the head of the upper arm bone is forced out of the shoulder socket. Shoulder instabilities have been classified according to the etiology, the direction of instability, or on combinations thereof. The Thomas and Matsen classification, which is currently the most commonly utilized classification, divides shoulder instability events into the traumatic, unidirectional, Bankart lesion, and surgery (TUBS) and the atraumatic, multidirectional, bilateral, rehabilitation, and capsular shift (AMBRI) categories. The acquired instability overstress surgery (AIOS) category was then added. Surgical procedures for shoulder instability includes arthroscopic capsuloplasty, remplissage, bone block procedure or Latarjet procedure. Reverse total shoulder arthroplasty (RTSA) represents a good solution for the management of patients with osteoarthritis or fracture of the proximal humerus, with associated severe osteoporosis and RC dysfunction

Glutamate regulates the expression of apoptosis-related genes and triggers the apoptosis of fibroblasts in rotator cuff tendons. Subacromial bursitis is always accompanied by symptomatic rotator cuff tear (RCT). However, no study has been reported on the presence of glutamate in subacromial bursa and on its involvement of shoulder pain in patients who had RCT. The purposes of this study were to determine whether the glutamate expression in subacromial bursa is associated with the presence of RCT and with the severity of shoulder pain accompanying RCT. Subacromial bursal tissues were harvested from patients who underwent arthroscopic rotator cuff tendon repair or glenoid labral repair with intact rotator cuff tendon. Glutamate tissue concentrations were measured, using a glutamate assay kit. Expressions of glutamate and its receptors in subacromial bursae were histologically determined. The sizes of RCT were determined by arthroscopic findings, using the DeOrio and Cofield classification. The severity of shoulder pain was determined, using visual analog scale (VAS). Any associations between glutamate concentrations and the size of RCT were evaluated, using logistic regression analysis. The correlation between glutamate concentrations and the severity of pain was determined, using the Pearson correlation coefficient. Differences with a probability <0.05 were considered statistically significant. Glutamate concentrations showed significant differences between the torn tendon group and the intact tendon group (P = 0.009). Concentrations of glutamate significantly increased according to increases in tear size (P < 0.001). In histological studies, the expressions of glutamate and of its ionotropic and metabotropic receptors have been confirmed in subacromial bursa. Glutamate concentrations were significantly correlated with pain on VAS (Rho=0.56 and P =0.01). The expression of glutamate in subacromial bursa is significantly associated with the presence of RCT and significantly correlated with its accompanying shoulder pain. Acknowledgements: This research was supported by the Basic Science Research Program, through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A3A01018955 and 2017R1D1A1B03035232)

Tear pattern and tendon involvement are risk factors for the development of a pseudoparalytic shoulder. However, some patients have similar tendon involvement but significantly different active forward flexion. In these cases, it remains unclear why some patients suffer from pseudoparalysis and others with the same tear pattern show good active range of motion. Moment arms (MA) and force vectors of the RC and the deltoid muscle play an important role in the muscular equilibrium to stabilize the glenohumeral joint. Biomechanical and clinical analyses were conducted calculating different MA-ratios of the RC and the deltoid muscle using computer rigid body simulation and a retrospective radiographic investigation of two cohorts with and without pseudoparalysis and massive RC tears. Idealized MAs were represented by two spheres concentric to the joints centre of rotation either spanning to the humeral head or deltoid origin of the acromion. Individual ratios of the RC /deltoid MAs on antero-posterior radiographs using the newly introduced Shoulder Abduction Moment (SAM) Index was compared between the pseudoparalytic and non-pseudoparalytic patients. Decrease of RC activity and improved glenohumeral stability (+14%) was found in simulations for MA ratios with larger diameters of the humeral head which also were consequently beneficial for the (remaining) RC. Clinical investigation of the MA-ratio showed significant risk of having pseudoparalysis in patients with massive tears and a SAM Index <0.77 (OR=11). The SAM index, representing individual biomechanical characteristics of shoulder morphology has an impact on the presence or absence of pseudoparalysis in shoulders with massive RC tears

Introduction. The objective assessment of shoulder function is important for personalized diagnosis, therapies and evidence-based practice but has been limited by specialized equipment and dedicated movement laboratories. Advances in AI-driven computer vision (CV) using consumer RGB cameras (red-blue-green) and open-source CV models offer the potential for routine clinical use. However, key concepts, evidence, and research gaps have not yet been synthesized to drive clinical translation. This scoping review aims to map related literature. Method. Following the JBI Manual for Evidence Synthesis, a scoping review was conducted on PubMed and Scholar using search terms including “shoulder,” “pose estimation,” “camera”, and others. From 146 initial results, 27 papers focusing on clinical applicability and using consumer cameras were included. Analysis employed a Grounded Theory approach guided iterative refinement. Result. Studies primarily used Microsoft Kinect (infrared-based depth sensing, RGB camera; discontinued) or monocular consumer cameras with open-source CV-models, sometimes supplemented by LiDAR (laser-based depth sensing), wearables or markers. Technical validation studies against gold standards were scarce and too inconsistent for comparison. Larger range of motion (RoM) movements were accurately recorded, but smaller movements, rotations and scapula tracking remained challenging. For instance, one larger validation study comparing shoulder angles during arm raises to a marker-based gold-standard reported Pearson's R = 0.98 and a standard error of 2.4deg. OpenPose and Mediapipe were the most used CV-models. Recent efforts try to improve model performance by training with shoulder specific movements. Conclusion. Low-cost, routine clinical movement analysis to assess shoulder function using consumer cameras and CV seems feasible. It can provide acceptable accuracy for certain movement tasks and larger RoM. Capturing small, hidden or the entirety of shoulder movement requires improvements such as via training models with shoulder specific data or using dual cameras. Technical validation studies require methodological standardization, and clinical validation against established constructs is needed for translation into practice

Introduction and Objective. Only few studies have investigated the outcome of exercises in patients with glenohumeral osteoarthritis (OA) or rotator cuff tear arthropathy (CTA), and furthermore often excluded patients with a severe degree of OA. Several studies including a Cochrane review have suggested the need for trials comparing shoulder arthroplasty to non-surgical treatments. Before initiation of such a trial, the feasibility of progressive shoulder exercises (PSE) in patients, who are eligible for shoulder arthroplasty should be investigated. The aim was to investigate whether 12 weeks of PSE is feasible in patients with OA or CTA eligible for shoulder arthroplasty. Moreover, to report changes in shoulder function and range of motion (ROM) following the exercise program. Materials and Methods. Eighteen patients (11 women, 14 OA), mean age 70 years (range 57–80), performed 12 weeks of PSE with 1 weekly physiotherapist-supervised and 2 weekly home-based sessions. Feasibility was measured by drop-out rate, adverse events, pain and adherence to PSE. Patients completed Western Ontario Osteoarthritis of the Shoulder (WOOS) score and Disabilities of the Arm, Shoulder and Hand (DASH). Results. Two patients dropped out and no adverse events were observed. Sixteen patients (89%) had high adherence to the physiotherapist-supervised sessions. Acceptable pain levels were reported. WOOS improved mean 23 points (95%CI:13;33), and DASH improved mean 13 points (95%CI:6;19). Conclusions. PSE is feasible, safe and may improve shoulder pain, function and ROM in patients with OA or CTA eligible for shoulder arthroplasty. PSE is a feasible treatment that may be compared with arthroplasty in a RCT setting

Introduction. Supraspinatus and infraspinatus tears (Massive Rotator Cuff Tear- MRCT) cause compensatory activation of the teres minor (TM) and subscapularis (SubS) to maintain humeral head alignment. This study measures force changes in TM and SubS using a dynamic shoulder testing setup. We hypothesize that combining superior capsule reconstruction (SCR) and lower trapezius tendon (LTT) transfer will correct rotator cuff forces. Methods. Eight fresh-frozen human shoulder specimens from donors aged 55-75 (mean = 63.75 years), balanced for gender, averaging 219.5 lbs, were used. Rotator cuff and deltoid tendons were connected to force sensors through a pulley system, with the deltoid linked to a servohydraulic motor for dynamic force measurement. The system allowed unrestricted humeral abduction from 0 to 90 degrees. Results. Teres Minor (TM):. -. Control: 7.43 N (SD = 1.66). -. SS tear: 5.46 N (SD = 1.45). -. MRCT: 3.94 N (SD = 1.43). -. LTT post-MRCT: 5.85 N (SD = 1.13). -. SCR post-MRCT: 4.68 N (SD = 0.71). -. Combined LTT+SCR: 6.43 N (SD = 1.24). -. TM force reduction: 26.51% post-SS tear, 46.97% from intact to MRCT, 63.20% increase with LTT+SCR. Subscapularis (SubS):. -. Control: -0.73 N (SD = 0.43). -. SS tear: -0.46 N (SD = 0.36), 36.99% increase. -. MRCT: 0.96 N (SD = 0.47), 31.51% increase. -. LTT post-MRCT: -0.32 N (SD = 0.47), 66.67% reduction. -. SCR post-MRCT: -0.28 N (SD = 0.16), 70.83% reduction. -. Combined LTT+SCR: -0.66 N (SD = 0.32), 31.25% reduction. Non-parametric Friedman's ANOVA showed overall statistical significance for TM (P = 1.083×10. -6. ) and SubS (P = 4.77×10. -4. ). Conclusion. The cadaveric model assesses rotator cuff compensations, showing significant TM force reductions following rotator cuff tears and improvements with LTT and SCR, particularly when combined. SubS exhibited negative force during normal abduction but compensated during MRCT, returning to normal values post-LTT and SCR

Abstract. Introduction. Local anaesthetic injections are regularly used for perioperative pain relief for shoulder arthroscopies. In our practice all shoulder arthroscopies were performed under general aneasthesia supplemented by perioperative subacromial local anaesthetic injections or landmark guided axillary nerve together with suprascapular nerve injections. We compared pain relief achieved with these two methods. We hypothesized that the selective nerve blocks would provide better post operative pain relief as described in literature. Methods. We conducted a retrospective cohort study on two patient groups with 17 patients each. Group one patients received 20mls 50:50 mixture of 1% lignocaine and 0.5% chirocaine injections before and after start of procedure and group two patients received 20 mls of chirocaine around the axillary and suprascapular nerves. VAS scores were collected at 1 and 4 hours and analgesia taken during the first 24 hours was recorded. Results. No significant difference in pain scores was noted but analgesia requirements in the nerve block group were higher. Conclusion. Landmark guided nerve blocks did not show any advantage over subacromial local anaesthetic in our study. This is in contrast to published literature and we believe subacromial injections are more reliable and reproducible. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Newer irreversible oral anticoagulants such as rivaroxaban, a direct factor 10a inhibitor, are increasingly employed to prevent thromboembolic events in atrial fibrillation (AF) patients, and to manage venous thromboembolism (VTE). Unlike warfarin, these agents require no monitoring and involve infrequent dose adjustment. We report the case of a patient treated with rivaroxaban for AF. Patient presented with unprovoked sudden onset right shoulder pain which clinically resembled shoulder haemarthrosis. A single case was anonymised and retrospectively reviewed through examination of clinical and radiographic data. A 70 year old female with known AF presented to Accident and Emergency with sudden onset of right shoulder pain and limited movement, which developed over one hour. The pain was constant, localised to the shoulder and without trauma. Past medical history included severe aortic regurgitation and associated thoracic aortic aneurysm, heart failure, atrial fibrillation and hypertension. Observations were normal upon admission with no haemodynamic compromise or pyrexia. Examining the right shoulder demonstrated distension of shoulder joint capsule, tenderness and a reduced range of movement. Temperature and neurovascular status in the right arm were normal. Investigations upon admission included an INR of 1.2. An anteroposterior right shoulder radiograph showed no evidence of fracture. Patient was managed conservatively with simple oral analgesia. Importantly, rivaroxaban was withheld for 5 days and symptoms resolved. Warfarin therapy was subsequently commenced instead as treatment for AF. Patient was discharged one week later and seen in clinic two weeks post-discharge. A full recovery occurred and with a full range of movement in the right shoulder. In the UK, current National Institute for Health and Care Excellence (NICE) guidelines recommend the use of factor 10a inhibitors, for prevention of stroke in AF patients, and following elective total hip and knee replacement operations to prevent VTE. In turn, rivaroxaban is increasingly prescribed as first line therapy. Whereas warfarin has a documented association with haemarthrosis, there is no primary literature evaluating the incidence of factor 10a therapy associated haemarthrosis. In our case, the unprovoked shoulder haemarthrosis resolved following rivaroxaban cessation. In comparison with warfarin, rivaroxaban is irreversible. With warfarin and a high INR, vitamin K can be used to reverse the anticoagulation. There is no equivalent for rivaroxaban. We suggest further studies into incidence of haemarthrosis associated with oral anticoagulant therapy be undertaken, and treating physicians be aware of such complication

Aim. Prospectively assess the degree of finger swelling after shoulder arthroscopy, to determine whether rings should be routinely removed prior to surgery. Method and Results. Patients undergoing shoulder arthroscopic procedures had finger diameters measured prior and post surgery, over a three month period. The study was approved by our Research and Development department. Measurements were taken using a finger circumference gauge (Southpointe, Florida, USA) and were all performed by one researcher in a standard technique, to eliminate inter observer variability. Control measurement, using the contralateral hand, were taken. Statistical analysis was performed, using the Mann Whitney U test. 31 patients undergoing shoulder arthroscopy were included in the study and had finger diameters assessed. The median amount of finger swelling on the operated side was 2.8 mm (IQR 4.6) per digit, compared to 0 mm on the contralateral side (IQR 1.6), which was significantly greater (p=0.0003). There was no statistical difference in the amount of finger swelling when patients undergoing short procedures (less than 30 minutes operating time) were compared to patients undergoing long procedures (greater than 60 minutes). Conclusions. These results suggest that patients undergoing shoulder arthroscopy have a significant degree of finger swelling post-operatively and that the amount of swelling cannot be accurately predicted based on the length of procedure alone. This indicates that rings should be routinely removed, prior to shoulder arthroscopy, even if this necessitates cutting of rings for removal

Subacromial bursa fibrosis are linked to rotator cuff lesion with shoulder stiffness; however, the mechanism underlying this shoulder disorder remain elusive. MicroRNA-29s (miR-29s) are emerging fibrosis inhibitor targeting fibrogenic matrices during tissue fibrosis. This study is aimed to investigate clinical relevance and function of miR-29 signalling to subacromial bursa homeostasis in shoulder stiffness. Subacromial bursa in patients with rotator cuff lesion with or without shoulder stiffness who required open acromioplasty were harvested for assessing fibrosis histopathology using Manson's trichrome staining. Expressions of proinflammatory cytokines, fibrotic matrices, and miR-29s were quantified using RT-PCR and in situ hybridization. Range of motion and pain scores of the stiffness group were higher than those of non-stiffness group. Upregulated proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and fibrotic matrices (collagen 1α1, 3α1, and 4α1) but decreased miR-29a and b expression existed in the stiffness group. Affected tissues exhibited severe fibrotic matrix accumulation, synovial hyperangiogenesis, hyperplasia, and strong miR-29a transcripts. In vitro, IL-1β rather than IL-6 and TNF-α decreased miR-29a expression of subacromial bursa fibroblasts. miR-29a knockdown escalated fibrotic matrix expression, whereas forced miR-29a expression alleviated the IL-1β-induced fibrotic matrix expression. Of interest, miR-29a transgenic mice displayed moderate responses to supraspinatus and infraspinatus tenotomy-induce fibrosis and gait irregularity of affected shoulders. Weak miR-29 signalling causes excessive fibrosis and remodelling in subacromial bursa and ultimately increases the prevalence of shoulder stiffness. This study reveals a new mechanistic underlying shoulder stiffness and highlights that sustained miR-29a potentially ameliorates the severity and function of stiff shoulder

Introduction. The highest incidence of recurrent shoulder instability is in young patients, surgical repair can reduce recurrent instability and improve shoulder function. This has led to an increasing rate of stabilisation and use of MRI to identify associated injuries in first time dislocations. MRA has the benefit of distending the joint and is becoming increasingly used. The aim of this study is to establish the sensitivity and specificity of MRA in the investigation of patients with traumatic anterior shoulder dislocations. Methods. A retrospective analysis of patients undergoing both magnetic resonance arthrography and arthroscopy after a traumatic anterior shoulder dislocation between January 2011 and 2014. Images were interpreted by eight musculoskeletal radiologists and arthroscopic findings were obtained from surgical notes and used as a reference. The sensitivity, specificity and positive predictive value for the different injuries were calculated. Results. 60 patients were reviewed; 88% were male, mean age was 28 years (range 18 to 50) and 27% were primary dislocations. The overall sensitivity and specificity of MRA to all associated injuries was 0.9 (CI 0.83–0.95) and 0.94 (CI 0.9–0.96) retrospectively. The lowest sensitivity was seen in osseous Bankart 0.8 (CI 0.44–0.96) and SLAP lesions 0.5 (CI 0.14–0.86). Conclusion. MRA has a high sensitivity when used to identify associated injuries in shoulder dislocation although in 8 patients (13%) arthroscopy identified an additional injury. The overall agreement between MRA and arthroscopic findings was good but identification of GHL and rotator cuff injuries was poor. Level of Evidence. IV. Conflict of Interests. The authors confirm that they have no relevant financial disclosures or conflicts of interest. Ethical approval was not sought as this was a systematic review

Wear of polymeric glenoid components has been identified as a cause of loosening and failure of shoulder implants1,2 in vivo. A small number of shoulder joint simulators have been built for in vitro wear testing, however none have been capable of testing with physiological motion patterns in three axes and with physiological loading. The Newcastle Shoulder Wear Simulator was designed with three axes of motion, which are programmable so that different activities of daily living might be replicated. The simulator uses three pneumatic cylinders with integral position encoders to move five shoulder prostheses simultaneously in the flexion-extension, abduction-adduction, and internal-external rotation axes. Axial loading is applied with pneumatic cylinders supplied from a pneumatic proportional valve via a manifold, which also supplies a sixth static control station. In order to establish if that the machine can actually perform as intended, commissioning trials were conducted replicating lifting a 0.5 Kg weight to head height as a daily living activity. During the commissioning trials JRI Orthopaedics Reverse VAIOS shoulder prostheses were tested in 50% bovine serum at ambient temperature. The results show that the shoulder joint wear simulator can satisfactorily reproduce a daily living activity deliberately selected for having a large range of motion and loading. Other daily activities, such as drinking from a mug, are less demanding in the ranges of motion and loading and represent no difficulty in being reproduced on the simulator. Now successfully commissioned, this new multi-station shoulder wear simulator can wear test current and new designs of shoulder prosthesis in vitro

Total Shoulder Arthroplasty (TSA) is a solution to fixing shoulder complications and restoring normal shoulder functionality. Shoulder arthritis is one of the common indicators of TSA. Studies suggest that 15% and 7% of the total Rheumatoid Arthritis (RA) and Osteoarthritis (OA) patients respectively, in sub-Saharan Africa, have degenerated shoulders. These patients are implanted with a Total Shoulder Prosthesis (TSP). There are limited literature available on the morphometric features of African shoulders. Previous studies have indicated that differences in shoulder surface geometry of the European and African populations, exists. This study aims at identifying the structural differences of the humeral articulating surfaces between South African and Swiss data sets. The South African data set included the Computerised Tomography (CT) scans of cadavers sourced from the University of Cape Town and the Swiss data set included the cadaver CT scans obtained from the SICAS Medical Image Repository. Sixty reconstructed models of humerus were generated from these scans of 30 (bilateral) healthy cadavers (15 South African and 15 Swiss) using Mimics®. The humeral articulating surfaces were separated from the shaft by performing in-silico surgery using SOLIDWORKS®, according to the guidelines provided orthopaedic surgeons. A Matlab code was generated to determine the superior-inferior (S-I) and the anterior-posterior (A-P) circular diameter and the peak points (PPs) of the articulating surfaces. The PPs were defined as the highest point on the articulating surface, which is most likely to be in contact with the glenoid. The S-I diameter was found to be significantly greater (p<0.01) than the A-P diameter for both the data sets (average difference = 5.02mm). Both the average A-P and S-I diameter for the Swiss data set were significantly larger (p = 0.02 and p = 0.03) than the South African data set by 2.36 mm and 2.70 mm respectively. The PPs were found to lie at an off-set from the origin. in case of the Swiss data set the average PP lie on the superior-posterior (S-P) quadrant and for the South African data set the average PP was found to lie on the anterior-inferior (A-I) quadrant. The A-P variation on the position of PP was highly significant (p = 0.003). The results obtained in this study sheds light on the observed morphological variations between the South African and Swiss data sets. The observed circular diameter values are similar to the literature. The observed results suggest that the average TSP needed for the Swiss data set would have been larger than the ones needed for the South African data set. PP is a novel feature which has not been studied extensively. The fact that the average Swiss data set PP lie in the S-P quadrant might suggest that these humeral heads are more retroverted and superiorly tilted when compared to the South African data set. These morphometric variations can play a major role in post-TSA kinematics. The future scope of this study is to highlight other morphometric variations, if any, for the gleno-humeral articulating surfaces

Summary. Data of 663 patients with three different pathologies were examined. We found that using patients with significant symptoms and functional difficulty in the opposite shoulder will not bias the results of observational studies if outcomes are based on routine disability measures such as ASES or Constant-Murley scores. Introduction. Recently, using patients with bilateral limb problems as independent cases has raised concerns in orthopaedic research due to violating the assumption of independence. If observations are too similar in characteristics, they become highly correlated which leads to lowering the variance and biasing the results. Type of pathology (impingement, cuff tear, osteoarthritis) and aging are expected to affect the incidence of bilateral shoulder complaints and should be considered when examining potential bias in this area. In addition, the impact of dominant side pathology has not been investigated primarily in patients with shoulder problems. The objectives of this study were: 1) to examine the incidence of bilateral shoulder complaints and pathology on the dominant side in patients with impingement syndrome, rotator cuff tear and osteoarthritis of the glenohumeral joint, 2) to explore the role of sex and age in developing bilateral shoulder complaints, and 3) to examine the impact of bilaterality and hand dominance on pre and one year post-operative disability. Patients and Methods. This study involved review of data of patients with a diagnosis of impingement syndrome, rotator cuff tears and osteoarthritis (OA) of the gleno-humeral joint who had undergone surgery and had returned for their one year follow-up. Two outcome measures were used; the American Shoulder & Elbow Surgeons (ASES) and the Constant Murley score (CMS). Results. Data of 663 patients (317 females; 269 impingement syndrome, 290 rotator cuff tear, 104 osteoarthritis) were included in the analysis. There was a difference in the incidence of bilateral symptoms in patients with different pathologies: osteoarthritis 46%, impingement 26%, and rotator cuff tears 23% (p<0.0001). The incidence of dominant side involvement was 70%, 68% and 50% in patients with rotator cuff tear, impingement syndrome and osteoarthritis (p=0.003). Neither bilaterality nor dominant arm pathology had a negative impact on disability (p>0.05). Discussion/Conclusion. Type of pathology and aging affect the incidence of bilateral shoulder symptoms. Rotator cuff related pathologies affect the dominant side more frequently. The most interesting finding of this study was related to lack of influence of bilateral symptoms or dominant side pathology on reported disability in three different pathology groups with different prevalence of disease

Background. Shoulder pain limits range of motion (ROM) and reduces performing activities of daily living (ADL). Objective assessment of shoulder function could be of interest for diagnosing shoulder pathology or functional assessment of the shoulder after therapy. The feasibility of 2 wearable inertial sensors for functional assessment to differentiate between healthy subjects and patients with unilateral shoulder pathology is investigated using parameters as asymmetry. Methods. 75 subjects were recruited into this study and were measured for at least 8 h a day with the human activity monitor (HAM) sensor. In addition, patients completed the Disability of the Arm, Should and Hand (DASH) score and the Simple Shoulder Test (SST) score. From 39 patients with a variety of shoulder pathologies 24 (Age: 53.3 ± 10.5;% male: 62.5%) complete datasets were successfully collected. From the 36 age-matched healthy controls 28 (Age: 54.9 ± 5.8;% male = 57.1%) full datasets could be retrieved. Activity parameters were obtained using a self-developed algorithm (Matlab). Outcome parameters were gyroscope and accelerometry-based relative and absolute asymmetry scores (affected/unaffected; dominant/non-dominant) of movement intensity. Results & Discussion. The absolute and relative asymmetry scores of the accelerometry-based intensity results for a threshold of > 0.1 g (AUC 0.821 and AUC 0.827) proved to be slightly more distinctive to the gyroscope-based intensity results for a threshold of > 10 deg/s (AUC 0.807 and 0.795) to distinguish between the healthy group and the shoulder group. Asymmetry (< 1%) was nearly absent in healthy controls (5/56 subjects) using the accelerometry-based intensity (> 0.1g) results but common in patients (29/48 subjects). A moderate, significant correlation was found between the asymmetry scores and the DASH score, thus complementary use is advised. The asymmetry scores had no correlation to the SST score. Conclusion. Ambulant assessment of shoulder activity using human activity monitors, containing a gyroscope and accelerometer, during ADL is feasible. The accelerometry-based and gyroscope-based absolute and relative asymmetry scores are promising parameters to diagnose or assess function of the shoulder. A moderate correlation was found between the DASH score and the activity monitor parameters, suggesting both could be used complementary to assess function

The advent of modular implants aims to minimise morbidity associated with revision of hemiarthroplasty or total shoulder arthroplasty (TSA) to reverse shoulder arthroplasty (RSR) by allowing retention of the humeral stem. This systematic review aimed to summarise outcomes following its use and reasons why modular humeral stems may be revised.

A systematic review of Pubmed, Medline and EMBASE was performed according to PRISMA guidelines of all patients undergoing revision of a modular hemiarthroplasty or TSA to RSR. Primary implants, glenoid revisions, surgical technique and opinion based reports were excluded. Collected data included demographics, outcomes and incidence of complications.

277 patients were included, with a mean age of 69.8 years (44-91) and 119 being female. Revisions were performed an average of 30 months (6-147) after the index procedure, with the most common reason for revision being cuff failure in 57 patients. 165 patients underwent modular conversion and 112 underwent stem revision. Of those that underwent humeral stem revision, 18 had the stem too proximal, in 15 the stem was loose, 10 was due to infection and 1 stem had significant retroversion. After a mean follow up of 37.6 months (12-91), the Constant score improved from a mean of 21.8 to 48.7. Stem revision was associated with a higher complication rate (OR 3.13, 95% CI 1.82-5.39).

The increased use of modular stems has reduced stem revision, however 40% of these implants still require revision due to intra-operative findings. Further large volume comparative studies between revised and maintained humeral stems post revision of modular implants can adequately inform implant innovation to further improve the stem revision rate.

Wear of polyethylene is associated with aseptic loosening of orthopaedic implants and has been observed in hip and knee prostheses and anatomical implants for the shoulder. The reversed shoulder prostheses have not been assessed as yet. We investigated the volumetric polyethylene wear of the reversed and anatomical Aequalis shoulder prostheses using a mathematical musculoskeletal model. Movement and joint stability were achieved by EMG-controlled activation of the muscles. A non-constant wear factor was considered. Simulated activities of daily living were estimated from in vivo recorded data. After one year of use, the volumetric wear was 8.4 mm. 3. for the anatomical prosthesis, but 44.6 mm. 3. for the reversed version. For the anatomical prosthesis the predictions for contact pressure and wear were consistent with biomechanical and clinical data. The abrasive wear of the polyethylene in reversed prostheses should not be underestimated, and further analysis, both experimental and clinical, is required

This study compared the effect of a computer-assisted and a traditional surgical technique on the kinematics of the glenohumeral joint during passive abduction after hemiarthroplasty of the shoulder for the treatment of fractures. We used seven pairs of fresh-frozen cadaver shoulders to create simulated four-part fractures of the proximal humerus, which were then reconstructed with hemiarthroplasty and reattachment of the tuberosities. The specimens were randomised, so that one from each pair was repaired using the computer-assisted technique, whereas a traditional hemiarthroplasty without navigation was performed in the contralateral shoulder. Kinematic data were obtained using an electromagnetic tracking device. The traditional technique resulted in posterior and inferior translation of the humeral head. No statistical differences were observed before or after computer-assisted surgery. Although it requires further improvement, the computer-assisted approach appears to allow glenohumeral kinematics to more closely replicate those of the native joint, potentially improving the function of the shoulder and extending the longevity of the prosthesis

Magnetic resonance imaging (MRI) continues to become more widely accessible as an investigation, with an increasing number of scans being performed in the outpatient setting for suspected shoulder pathology. We performed a retrospective review of all shoulder MRI scans performed in an orthopaedic outpatient setting in a district general hospital between October 2010 and October 2011. We also reviewed the medical notes for these patients. 75 MRI Shoulder scans were performed on 74 patients. In 5 cases (7%), no other form of imaging was performed prior to MRI scan. 11 patients (15%) had no provisional diagnosis included in the referral. The nature of referral, indication for MRI and subsequent management of these patients was also examined. Our findings may support the use of guidelines for requesting MRI scans of the shoulder in outpatients

Summary Statement. Reverse shoulder design philosophy can impact external rotation moment arms. Lateralizing the humerus can increase the external rotator moment arms relative to normal anatomy. Introduction. The design of reverse shoulders continues to evolve. These devices are unique in that they are not meant to reproduce the healthy anatomy. The reversal of the fulcurm in these devices impacts every muscle that surrounds the joint. This study is focused on analyzing the moment arms for the rotator cuff muscles involved in internal and external rotation for a number of reverse shoulder design philosophies. Methods. Four of the most common design philosophies were chosen. The first, a Grammont style prosthesis, with a center of rotation (COR) on the glenoid face and a humeral cup countersunk into the proximal humerus (MGMH). The second concept is the MGMH design lateralised by a 10mm bone graft (BIO). The third concept has a lateralised glenosphere COR and a humeral component inside the proximal humerus (LGMH). The fourth design has a medialised COR with a humeral component placed on top of the humerus (MGLH). This places the humerus further lateral than the previous designs. For each component set, a representative implant was modeled based on published specifications. Each design was implanted into the same digital bone models (consisting of a humerus, scapula, clavicle, and ribcage) following the manufacturer's recommended surgical technique. The muscles analyzed were the posterior-deltoid (PD), subscapularis (SSC), infraspinatus (IS), and teres minor (TM). These muscles were allowed to wrap around the bone of the scapula and proximal humerus through the range of motion. All muscle origin and insertion points were kept constant throughout the analysis. The assemblies were externally rotated from an initial position of 45° internal rotation to 45° of external rotation of the humerus with the arm at 0° of abduction. The moment arms for all muscles were compared to those calculated for the anatomic shoulder. Results. All the rotator cuff muscles displayed a similar trend with the reverse shoulder. The external rotators all had similar moment arm values at neutral (IS∼22mm, TM∼20mm), but increased at rates proportional to their humeral offsets with external rotation (IS-MGLH 32.3mm, LGMH 27.5mm, MGMH and BIO 26.25mm; TM-MGLH 31.3mm, LGMH 27.8mm, MGMH and BIO 26.5mm). The SSC internal rotation moment arm remains roughly constant at 20mm for the anatomic shoulder, but varies widely from 45° external to 45° internal rotation with the different designs (MGLH 31.4mm to 6.7mm; MGMH 25.1mm to 11.2mm; LGMH 26.2mm to 10.8mm; BIO 25.4mm to 4.8mm). The PD moment arm is increased relative to the anatomic shoulder during external rotation for the MGLH design (9.3mm vs. 7.4mm). The other designs exhibit a decrease in the moment arm of this muscle relative to the anatomic design (LGMH 7.3mm, MGMH 5.8mm, BIO 6.4mm). Discussion. The lateral offset between the center of humeral axis and the muscle insertion on the humerus dominates the external rotation moment arm value through this range of motion. This is evident by the increase in the moment arms with external rotation for the different reverse shoulder designs. The increase in external rotation efficiency for the external rotators and PD could play a critical role in post-operative external rotation strength and motion