Objectives: A stable shoulder is essential for proper elbow and hand function after oncologic resection of the shoulder girdle. We describe a surgical technique for replacing the shoulder joint capsule using synthetic mesh after resections of the shoulder girdle that resulted in gross intraoperative instability of the shoulder joint. Methods: 68 patients who underwent shoulder girdle resection between 1989 and 2006 were identified in our prospective database. This report focuses on nine patients whose shoulder joint was reconstructed with synthetic mesh. All patients were followed on a 3 monthly basis. Shoulder joint instability was determined from clinical records, database and radiographs. Results: Nine patients underwent shoulder joint reconstruction with synthetic mesh. One patient underwent a shoulder disarticulation within 30 days of the index surgery and was excluded from this rapport. No dislocations were noted during follow-up (range 3–48 months). Radiographs revealed an average vertical displacement of the humeral head compared to its original position of 0.7 cm (range 0–1.7 cm). There were two surgical complications. In one patient the humeral prosthesis migrated proximally and eroded through the skin requiring additional surgery. In another case erosion of the distal clavicle was noted. This was biopsied and foreign body reaction identified. Conclusions: Joint instability following major resections of the shoulder girdle is a source of morbidity and affects the function of the salvaged limb. Synthetic capsular reconstruction using Marlex mesh is a useful adjunct in patients where insufficient shoulder musculature and joint capsule remains after resection to allow for stable suspension of the upper limb

Aims. Is it feasible to conduct a definitive multicentre trial in community settings of corticosteroid injections (CSI) and hydrodilation (HD) compared to CSI for patients with frozen shoulder? An adequately powered definitive randomized controlled trial (RCT) delivered in primary care will inform clinicians and the public whether hydrodilation is a clinically and cost-effective intervention. In this study, prior to a full RCT, we propose a feasibility trial to evaluate recruitment and retention by patient and clinician willingness of randomization; rates of withdrawal, crossover and attrition; and feasibility of outcome data collection from routine primary and secondary care data. Methods. In the UK, the National Institute for Health and Care Excellence (NICE) advises that prompt early management of frozen shoulder is initiated in primary care settings with analgesia, physiotherapy, and joint injections; most people can be managed without an operation. Currently, there is variation in the type of joint injection: 1) CSI, thought to reduce the inflammation of the capsule reducing pain; and 2) HD, where a small volume of fluid is injected into the shoulder joint along with the steroid, aiming to stretch the capsule of the shoulder to improve pain, but also allowing greater movement. The creation of musculoskeletal hubs nationwide provides infrastructure for the early and effective management of frozen shoulder. This potentially reduces costs to individuals and the wider NHS perhaps negating the need for a secondary care referral. Results. We will conduct a multicentre RCT comparing CSI and HD in combination with CSI alone. Patients aged 18 years and over with a clinical diagnosis of frozen shoulder will be randomized and blinded to receive either CSI and HD in combination, or CSI alone. Feasibility outcomes include the rate of randomization as a proportion of eligible patients and the ability to use routinely collected data for outcome evaluation. This study has involved patients and the public in the trial design, dissemination methods, and how to include groups who are underserved by research. Conclusion. We will disseminate findings among musculoskeletal clinicians via the British Orthopaedic Association, the Chartered Society of Physiotherapy, the Royal College of Radiologists, and the Royal College of General Practitioners. To ensure wide reach we will communicate findings through our established network of charities and organizations, in addition to preparing dissemination findings in Bangla and Urdu (commonly spoken languages in northeast London). If a full trial is shown to be feasible, we will seek additional National Institute for Health and Care Research funding for a definitive RCT. This definitive study will inform NICE guidelines for the management of frozen shoulder. Cite this article: Bone Jt Open 2024;5(3):162–173

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

Introduction: Despite a multitude of reports detailing the management of infected hips and knees with or without arthroplasty, only little information is available on how to deal with infected shoulders. Besides primary haematogenous infection, the increasing number of surgical procedures (infiltration, arthroscopy, ORIF, total- or hemi arthroplasty) confront the orthopaedic surgeon increasingly with this devastating complication. Our goal is to present our experience with the use of a cement spacer in the treatment of infected shoulder joints. Material and Methods: Between 1995 and 2005 9 patients were diagnosed with deep shoulder infection. The study includes 5 women and 4 men. The mean age at the time of diagnosis of the infection was 65 years (range, 51–78 years). Only 2 patient had had no prior surgery of the shoulder. 5 patients had an infection of a shoulder arthroplasty and 2 patients had been treated with ORIF for fracture. All of the patients underwent resection the humeral head or retrieval of the arthroplasty with large debridement followed by implantation of an antibiotic impregnated polymethyl methacrylate spacer. After a mean duration of two months of antibiotics and after normalisation of the CRP a delayed reimplantation of a prosthesis was performed in 6 patients. One patient is awaiting arthroplasty, while two patients are satisfied with the functional result obtained with the spacer and do not want further surgery. Results: None of the patients developed recurrent infection at an average follow-up time of 36 months. Shoulder function was judged objectively and subjectively to be at least satisfactory in all of the patients. Conclusions: Staged treatment of infected shoulders using antibiotic impregnated polymethyl methacrylate spacers showed in our small group of patients, good and reproducible results. The individually moulded and fitted spacer filling the joint cavity and restoring the normal anatomy of the shoulder after joint debridement makes secondary procedures much easier. In the cases of exchange prosthetic reconstruction no recurrent infection has been experienced and all of the patients have substantial pain relief and an adequate shoulder function. Based on this experience the authors think that staged treatment and the use of a cement spacer in infected shoulder joints is a valid approach

Aims: The aim of the study was to investigate the cap-suloligamentous structures of the shoulder joint and their association with rotator cuff tendons. Methods: Twenty seven alcohol-formalin-glycerol þxed right shoulder joints (age range 65 Ð 78 years) were investigated. The Ligg. coracohumerale, coracoglenoidale, glenohumeralia, semicirculare humeri and gleno-capsulare were dissected in þne detail. To visualise the rotator interval, the Processus coracoideus was cut at its base and moved together with the Ligg. coracohumerale and coracoglenoidale posteriorly. The analysis of the ligamentous structures and their relations with the rotator cuff tendons was performed. Results: The Lig. coracohumerale originated from Processus coracoideus and Lig. coracoglenoidale. It inserted into the Lig.semicirculare humeri Ð a capsular ligament spread between Tubercula minus et majus. Lig. glenocapsulare originated posterior to the Tuberculum supragle-noidale and inserted into the Lig. semicirculare humeri. The Mm. supra- and infraspinatus inserted into the Lig. semicirculare humeri. The anterior capsule was strengthened in addition to the three Ligg. glenohumeralia with a Lig. glenohumerale spirale. It originated from the Tuberculum infraglenoidale, coursed craniolaterally and inserted together with the M. subscapularis tendon at the Tuberculum minus. Conclusions: The shoulder joint capsule is strengthened with the Ligg. coracohumerale, coracoglenoidale, glenohumeralia superior, medium, inferior et spirale and Ligg. semicirculare humeri et glenocapsulare. The close relation of the ligamentous structures with the tendons of the rotator cuff brings a new insight into the different glenohumeral pathologies

The numbers of anatomic total shoulder joint replacements (ATSR) is increasing during the past years with encouraging clinical results. However, the survivorship of ATSR is lower as compared to total knee and hip replacements. Although the reasons for revision surgery are multifactorial, wear-associated problems like loosening are well-known causes for long-term failure of ATSR. Furthermore there is lack of valid experimental wear tests for ATSR. Therefore the purpose of this study was to define experimental wear testing parameters for ATSR and to perform a wear study comparing ceramic and metallic humeral heads. Kinetic and kinematic data were adopted from in-vivo loading measurements of the shoulder joint (. orthoload.com. ) and from several clinical studies on shoulder joint kinematics. As activity an ab/adduction motion of 0 to 90° in combination with an ante/retroversion while lifting a load of 2 kg has been chosen. Also a superior-inferior translation of the humeral head has been considered. The wear assessment was performed using a force controlled AMTI joint simulator for 3×10. 6. cycles (Fig. 1) and polyethylene wear has been assed gravimetrically. The studied ATSR (Turon. TM. , DJO Surgical, USA) resulted in a polyethylene wear rate of 62.75 ± 1.60 mg/10. 6. cycles in combination with metallic heads. The ceramic heads significantly reduced the wear rate by 26.7 % to 45.99 ± 1.31 mg/10. 6. (p<0.01). The wear scars dimensions were in good agreement to clinical retrievals. This study is the first that experimentally studied the wear behavior of ATSR based on clinical and biomechanical data under load controlled conditions. In term of wear the analyzed ATSR could clearly benefit from ceramic humeral heads. However, in comparison to experimental wear studies of total knee and hip replacements the wear rate of the studied ATSR was relatively high. Therefore further research may focus on optimized wear conditions of ATSR and the hereby described method may serve as a tool to evaluate a wear optimization process

The glenohumeral joint is an important joint with large mobility of the human upper extremity. In shoulder arthroplasty patients often has an unsatisfactory outcome. In order to understand the biomechanical complexity of the shoulder, a novel computer controlled experimental shoulder simulator with an innovative muscle control were constructed. The main component of the simulator includes the active pneumatic muscles to replicate the deltoid and the rotator-cuff function and two springs as passive muscle. The aim of this study is to evaluate the impact of a variation of shoulder joint geometries on shoulder biomechanics in the basis of motion analysis. The radius of the glenoid cavity varied from 28–33mm with 2.5mm increment while the radius the humeral head are varied from 20.1–25.1 with 2.5mm increment. The “teach-in” function of the simulator allows an operator to assign the movement to the simulator where the lengths of the pneumatic muscles are recorded. Then the simulator repeats the assigned movement according to the recorded muscles length. The daily living activities includes abduction/adduction, internal/external rotation with adducted arm, and circumduction. The results show promising repeatability of the simulator with minor deviation. However, damage on the surface of the humeral head has been found which should be further studied for both shoulder behavior investigation and the shoulder simulator optimisation. Therefore, this study is a decent initial study toward the verification of the simulator and lead to a better understanding of shoulder biomechanical behavior to cope with the clinical problems in the future

Introduction and purpose: Different neurovascular structures may be damaged when making arthroscopic portals to the shoulder joint. The description of new portals poses new challenges. The goal of the present study is to provide an update on the anatomic vasculonervous responses of the current approaches to shoulder arthroscopy. Materials and methods: 16 fresh cadavers were systematically dissected. The most usual arthroscopic portals were marked and, then, the dissection started on a plane-to-plane basis. Relationships were identified and distances were measured to the most important neurovascular elements with a standard caliber (accuracy: 0.5mm). Results: The portals studied and the structures at risk were the following:. * Posterior portal: anterior branch of the axillary nerve and posterior circumflex artery 3.4 cm (range: 1.4 – 5); cutaneous branch of the axillary nerve 6.3 cm (range: 3.8 – 8.3), suprascapular nerve 2.8 cm (range: 2.1–3.3). * Anterosuperior portal: main branch of the musculocutaneous nerve 6.5 cm (range: 3.8 – 11). * Lateral subacromial portal: axillary nerve and posterior circumflex artery 3.7 cm (range: 2– 5.5). * Anteroinferior subaxillary portal 4 cm (range: 3.1 –6). * Supraspinatus portal: suprascapular nerve 3.2 cm (range: 2.4 – 4). Conclusions: Although the crucial elements at risk when performing a shoulder arthroscopy are multiple, the axillary and suprascapular nerves were the most vulnerable structures to the different approaches. In spite of the presence of the “safe areas” described above, the neurovascular bundle was frequently affected by passage through the anteroinferior subaxillary portal. The results suggest that the use of this portal is not safe for routine arthroscopic practice

Aim

Clavicular osteotomy was described as an adjunct to deltopectoral approach for improved exposure of the glenohumeral joint. This study aims to present contemporary outcomes and complications associated with the routine use of clavicular osteotomy by a single surgeon in a regional setting within New Zealand.

Purpose: Surgical prosthetic treatment of excentred degeneration of the shoulder joint has long been limited to simple humeral prostheses. Inverted total shoulder arthroplasty (ITSA) using the Grammont system appears to provide real improvement. What is the comparative outcome? Does the Grammont prosthesis give constant results? Is the simple humeral prosthesis still indicated for selected cases? In order to respond to these questions, we reviewed 84 patients who had undergone surgery between 1986 and 2000 for implantation of 52 simple humeral prostheses (mean follow-up 7.1 years) and 32 ITSA (mean follow-up 4.3 years). Material and methods: Between 1986 and 1995, all patients with excentred degeneration of the shoulder joint were treated with a simple humeral prosthesis (36 cases). Between 1995 and 2000, either ITSA or simple humeral prosthesis (16 cases) was used. For the ITSA, indications were limited to excentred degeneration in patients aged over 70 years with a painful pseudoparalytic shoulder or contraindication for a simple prosthesis (alteration of the acromiocorocoid vault or the subscapular area). Simple prostheses were used either when an ITSA could not be implanted (patient too young, overly deteriorated glenoid, deltoid insufficiency) or when there was a preferential indication (excentred degeneration in young patients < 65 years, preservation of active motion, Favard type 1 or 2 glenoid…). Results: For the simple humeral prosthesis series (1986–1995): the Constant score improved from 16.4 preoperatively to 489.6 postoperatively; radiographically there were one humeral loosening, three superior migrations, and three glenoid degenerations; three revision procedures were required. For the ITSA: the Constant score improved from 14.2 preoperatively to 61.6 postoperatively; radiographically there was one humeral loosening; 32% glenoid alterations in Nérot grades 3 and 4; one revision procedure was required. For the later simple humeral protheses (1995–2000): the Constant score improved from 18.2 preoperatively to 56.4 postoperatively (60.2 excluding cases with a simple prosthesis due to contraindication of an ITSA); radiologically there were one superior migration and two glenoid deteriorations. Discussion: For a given indication, the results with the ITSA were better than with the simple prosthesis (p < 0.001). However, excluding salvage procedures where the ITSA could not be used, simple prostheses inserted for precise indications provided results nearly equivalent to the ITSA (p < 0.05) with less uncertainty concerning the future. For us, the inverted total shoulder prosthesis and the simple humeral prosthesis share indications for surgical repair of excentred degeneration of the shoulder joint

Purpose: The purpose of our work was to study the effects of sequential arthroscopic section of the anterior capsule of the shoulder joint using an experimental model of retractile capsulitis induced by heat treatment. Material and methods: Twelve cadaver shoulders were studied. Passive mobility was initially normal. Anterior capsule retraction was first created under arthroscopic control (Arthrocare® generator, power 2). Twelve programmed sequential sections were then performed successively using the thermal probe (Arthrocare®, power 9) on: the coracohumeral ligament (CHL) and the superior glenohumeral ligament (SGHL), the middle gleno-humeral ligament (MGHL), the inferior glenohumeral ligament (IGHL), and the intra-articular portion of the subscapular muscle tendon (SST). The posterior capsule was not studied. At each step, motion was measured independently by two operators. At the end of the sequence, the articulation was opened to verify the sections as was the absence of any injury to noble structures. Results: Measures were reproducible (mean difference 5° between two series). The sections were correctly achieved. Macroscopically, there were no injuries to noble structures. The role of the different elements studied were as follows: — rotator interval (CHL, SGHL): gain in RE1 (mean 40°) and RE2 (mean 35°) (greater than loss during retraaction; — IGHL: gain in elevation (mean 33°); — IGHL and rotator interval: potentialisation of gain in FE2 (mean 41°) and elevation (mean 50°); — MGHL: moderate increase in external rotation at 45° antepulsion and elevation (mean 20°); —SST: discrete gain in RE1 (10°) but risk of dislocation (n=1). Discussion: Our model was reproducible. Section of the anterior capsule by a thermal method did not produce macroscopic injury to neighboring tissues. Our study pointed out the preeminent importance of sectioning the rotator interval for recovering external rotation. This section, combined with section of the IGHL has a potentialsing effect. The limitation of our study is the absence of examination of the posterior capsule

Purpose: The purpose of this work was to compare outcome after hemiarthroplasty and after inverted arthroplasty for the treatment of excentred degeneration of the shoulder joint. Material and methods: This multicentric study inclued 136 patients, 110 women and 26 men, mean age 72.4 years (range 55 – 86 years) with 142 shoulder prostheses. Among the 142 shoulders operated on, 62 underwent Aequalis hemiarthroplasty and 80 inverted arthroplasty. The preoperative handicap was more severe in the hemiarthroplasty group (Constant score 26) than in the inverted arthroplasty group (Constant score 23). Results: Clinical and radiological follow-up data were collected at a mean follow-up of 44 months for the Aequalis prostheses and at 45 months for the inverted prostheses. There were seven failures requiring five revision procedures: three in the hemiarthroplasty group and four in the inverted arthroplasty group. The differences between the hemi- and inverted arthroplasty groups concerned the Constant score, which was significantly better in the inverted prostheses (65.5) than in the hemiarthroplasties (46.1), for all subscores. Active elevation was 138° for the inverted prostheses and 97° for the Aequalis prostheses (p < 0.01). Mean external rotation in position 1 was 22° for the Aequalis prostheses and 11° for the inverted prostheses (p < 0.01) with no difference in elevation rotation. These results remained equivalent and significant over time, even beyond five years. Radiographically, there was one case with an anomalous humeral component (impaction) in the inverted group. For the inverted prostheses, there were three migrations that have not been revised to date and three partial screw loosenings. The main problem was the development of notches in the scapular column observed in 50% of the cases including 20% which reached the lower screw. For the Aequalis prostheses, the main problem was deterioration of the acromial vault observed in 50% of the cases leading to altered function. Discussion: Inverted prostheses provide clearly better mid-term results, even after five years. With hemiarthroplasty there is a long-term risk of vault wear. The long-term course of the inverted prostheses is worrisome due to the notches in the scapular column and the stress on the fixation. These prostheses should be used preferably for old persons with a deteriorated vault

Our objective was to determine the plasma levels of substance P (SP) in patients with postoperative stiffness after arthroscopic rotator cuff repair.

Plasma samples were obtained at 15 months from surgery from 2 groups of patients who underwent arthroscopic repair of a rotator cuff tear. In Group 1, 30 subjects (14 men and 16 women, mean age: 64.6 years, range 47 to 78) with shoulder stiffness 15 months after arthroscopic rotator cuff repair were recruited. In Group 2, 30 patients (11 men and 19 women, mean age: 57.8 years, range 45 to 77) were evaluated 15 months after successful arthroscopic rotator cuff repair. Immunoassays were performed with commercially available assay kits to detect the plasma levels of SP.

The mean plasma levels of SP in patients with postoperative stiffness were significantly greater than those in the control group (81.06 ± 27.76 versus 23.49 ± 5.64, P < 0.05).

The plasma concentrations of substance P in patients with shoulder stiffness after arthroscopic rotator cuff repair are higher compared to plasma levels of SP in patients with a good postoperative outcome. The neuronal upregulation of SP shown in the plasma of patients with post operative shoulder stiffness may underlay not only the symptoms of adhesive capsulitis, but also its development.

Our aim was to determine the prevalence of shoulder symptoms in patients with type I compared to type 2 diabetes mellitus and evaluate the clinical presentation of patients diagnosed with adhesive capsulitis. This was a retrospective case-note review of 164 diabetic patients treated for shoulder symptoms from 1996 to 2007. Diabeta 3 for relevant Diabetic data. We used ANOVA, Tukey HSD, Chi-Square and Fisher’s Exact tests.

The incidence of treated shoulder patients in diabetic population: 1.04%. 86 males; 78 females. Average age 58 years (22 – 83). DM Type I 34% (46/136); Type II 66% (90/136). Mean duration of DM at presentation: 10 years (1–33). Mean HbA1c at presentation 8.3%. Retinopathy 16% (19/90); Neuropathy 12% (12/88).

The diagnoses were: Impingement 101 (62%); Adhesive Capsulitis 35 (21%); Cuff tear 17 (10%); Arthritis 11 (7%).

Mean recorded pre-treatment ROM: Impingement (flexion 117°, abduction 103°, ER 36°); Adhesive Capsulitis (flexion 90°, abduction 75°, ER 12°); Cuff tear (flexion 109°, abduction 95°, ER 45°); Arthritis (flexion 67°, abduction 93°, ER 18°).

Adhesive Capsulitis was significantly related to: HbA1c (9.9%); p< 0.001, Type I DM; p< 0.003, Duration of DM (average 17.5 yrs); p< 0.03.

An interesting statistically significant (p< 0.003) correlation was found between Type 2 DM and Impingement Syndrome.

Treatments included: Injection (53), MUA (49), Arthroscopy (99), Open Surgery (56). 82% patients satisfactorily discharged (mild/no pain and improved ROM: flexion > 150°, abduction > 150° and ER > 50°) after an average 3.4 months. Three referred to pain clinic, sixteen patients didn’t attend their follow-up appointment and seven died. Eleven relapsed (eight adhesive capsulitis).

Persistent symptoms were more common in Diabetic patients with adhesive capsulitis, which was found to be significantly related to Type I DM, its duration and control (HbA1c levels). Type II Diabetics are more likely to be affected with impingement syndrome. Close liaison with the Diabetology Department is essential for effective treatment of Diabetic Shoulder pathology.

Postoperative stiffness (POS) of the shoulder may occur after an apparently successful reconstruction of a rotator cuff tear.

The role of the peripheral nervous system in tissue healing has only recently been recognized.

We determined the plasma levels of SP in patients with postoperative stiffness after arthroscopic repair of a rotator cuff tear, and compared them with those in patients with a good outcome after arthroscopic rotator cuff repair.

Plasma samples were obtained at 15 months from surgery from 2 groups of patients who underwent arthroscopic repair of a rotator cuff tear. In Group 1, 30 subjects (14 men and 16 women, mean age: 64.6 years, range 47 to 78) with shoulder stiffness 15 months after arthroscopic rotator cuff repair were recruited. In Group 2, 30 patients (11 men and 19 women, mean age: 57.8 years, range 45 to 77) were evaluated 15 months after successful arthroscopic rotator cuff repair. Immunoassays were performed with commercially available assay kits to detect the plasma levels of SP.

Statistical analysis were performed with Wilcoxon Sign Rank test. Significance was set at P< 0.05

The concentrations of the neuropeptide SP in sera were measurable in all patients. Patients with postoperative stiffness had statistically significant greater plasma levels of SP than patients in whom arthroscopic repair of rotator cuff tears had resulted in a good outcome (P < 0.05)

Postoperative stiffness (POS) of the shoulder may occur after an apparently successful reconstruction of a rotator cuff tear.

An increased amount of SP in the subacromial bursa has been correlated with the pain caused by rotator cuff disease.

SP stimulates DNA synthesis in fibroblasts, which are the cellular components of the adhesive capsulitis of the shoulder. Also, SP is a pain transmitter peptide, and pain may cause a secondary muscular and/or capsular contracture.

Our results show that the plasma concentrations of substance P in patients with shoulder stiffness after arthroscopic rotator cuff repair are higher compared to plasma levels of SP in patients with a good postoperative outcome.

We cannot determine the cause of POS in our patients, but the findings of this study suggest a possible neuronal role in the pathophysiology of POS after arthroscopic repair of rotator cuff tears. The knowledge of the pathophysiological role of sensory nerve peptides in tissue repair in these patients could open new therapeutic options to manage conditions of the musculo-skeletal system with impaired tissue-nervous system interaction.

The presented study investigated the difference of positioning sense of the shoulder before and after surgery (capsular shift or Arthroscopic Bankart repair) for shoulder instability.

For this purpose a sample of patients with recurrent dislocations of the shoulder that underwent surgery and patients with instability before surgery volunteered to participate in a set of experiments. Their results were compared to the results obtained from a matching sample of healthy subjects.

All subjects completed all movement’s conditions that included the performance of hand movements towards memorized visual target in A-horizontal plane condition and B-Three dimensional movement condition.

The mixed design (3 groups x 3 2D levels x 3 3D levels) with repeated measures allowed the comparison among the groups in terms of final accuracy measures (Absolute and Variable Errors) and variability around mean tangential velocities and end-point paths.

The results showed that operative shoulder stabilization improves the ability to accurately position the arm on a target at the end of the movement and in addition the kinematic profile, which is disturbed before stabilization, improves as well.

These measures may be used as an objective tool to asses the success of conservative as well as operative treatment for shoulder instability.

The anterior portion of the anatomical neck is used as a reference for the osteotomy in shoulder arthroplasty. Resection at this level is thought to remove a segment of a sphere which can accurately be replaced with a prosthetic implant. The objective of the study was to analyse the cartilage/metaphyseal interface relative to an ideal osteotomy plane to define points of reference the may recover retroversion accurately. Data were collected from 24 humeri using a novel technique, combining data acquired using a Microscribe digitiser and surface laser scanner. Rhinocerus NURBS modelling software was used to analyse the Cartilage/metaphyseal interface. The retroversion angle was calculated for the normal geometry and for the standard osteotomy along the anterior cartilage/metaphyseal interface. An ideal osteotomy plane was then created for each specimen and the perpendicular distance from the cartilage/metaphyseal interface was determined, identifying points of least deviation. The reference points were used to simulate a new osteotomy for which retroversion was calculated. Paired t-tests were used to compare the novel osteotomy and traditional osteotomy to the normal geometry. The mean retroversion for the normal geometry was 18.5±9.0 degrees. The mean retroversion for the traditional osteotomy technique was 29.5±10.7 degrees, significantly different from the original (p< 0.001). The mean retroversion using the novel osteotomy was 18.9±8.9 degrees and similar to the normal geometry (p=0.528). The traditional osteotomy resulted in a mean increase in retroversion of 38%. The increase in version may result in eccentric load on the glenoid, an alteration to the rotator cuff balance and poor clinical outcome. The novel osteotomy based on points identified around the cartilage/metaphyseal interface that deviated least from an ideal osteotomy plane resulted in more accurate recovery of head geometry. The novel technique may improve clinical outcome. Further investigation is warranted.

Aim. Accurate diagnosis is key in correctly managing prosthetic joint infection(PJI). Shoulder PJI definition and diagnosis is challenging. Current PJI definitions, based overwhelmingly in hip/knee research, may not accurately diagnose shoulder PJI. Our aim is to compare the preoperative performance of two PJI definitions comparing it to definitive postoperative classification. Method. This is a retrospective study of patients who have undergone total shoulder revision surgery for infection between 2005 and 2022. Cases were classified using two different PJI definitions: a)the European Bone and Joint Infection Society (EBJIS) and; 2)the 2018 International Consensus Meeting(ICM) PJI specific shoulder definition. Preoperative classification was based on clinical features, inflammatory markers and synovial fluid leukocyte count and definitive classification also considered microbiology and histology results. Results. Preoperative and definitive PJI classification status of the 21 patients included were evaluated and is summarized in table 1. The shoulder specific 2018 ICM definition showed the highest agreement between preoperative and definitive classification (76.2%, k=0.153, p=0.006) compared to EBJIS (52.4%, k=0.205, p=0.006). In all cases, the classification was changed because of positive intraoperative microbiology (at least two identical isolates). Microbiology findings showed coagulase negative staphylococci, Staphyloccocus aureus and Cutibacterium acnes to be the most frequent. Four patients had polymicrobial infections. Conclusions. Both the EBJIS 2021 and 2018 ICM definitions have low accuracy in predicting shoulder PJI preoperatively. Clearly further studies with larger cohorts are in dire need focusing specifically on shoulder revision arthroplasty to improve on existing definitions. Caution is advised while extrapolating of criteria/thresholds recommended for hip/knee joints. For any tables or figures, please contact the authors directly

Aim

Propionibacterium acnes (PA) is an important cause of shoulder prosthetic joint infections (SPJIs) for which the optimal treatment has not yet been determined. Rifampicin and Levofloxacin both showed not benefit in recent experimental models of PA-SPJIs. We describe herein the experience of five different medical French centers in order to assess factors associated with patient's outcome with special emphasize on antibiotic regimens.

Analyzing shoulder kinematics is challenging as the shoulder is comprised of a complex group of multiple highly mobile joints. Unlike at the elbow or knee which has a primary flexion/extension axis, both primary shoulder joints (glenohumeral and scapulothoracic) have a large range of motion (ROM) in all three directions. As such, there are six degrees of freedom (DoF) in the shoulder joints (three translations and three rotations), and all these parameters need to be defined to fully describe shoulder motion. Despite the importance of glenohumeral and scapulothoracic coordination, it's the glenohumeral joint that is most studied in the shoulder. Additionally, the limited research on the scapulothoracic primarily focuses on planar motion such as abduction or flexion. However, more complex motions, such as internally rotating to the back, are rarely studied despite the importance for activities of daily living. A technique for analyzing shoulder kinematics which uses 4DCT has been developed and validated and will be used to conduct analysis. The objective of this study is to characterize glenohumeral and scapulothoracic motion during active internal rotation to the back, in a healthy young population, using a novel 4DCT approach. Eight male participants over 18 with a healthy shoulder ROM were recruited. For the dynamic scan, participants performed internal rotation to the back. For this motion, the hand starts on the abdomen and is moved around the torso up the back as far as possible, unconstrained to examine variability in motion pathway. Bone models were made from the dynamic scans and registered to neutral models, from a static scan, to calculate six DoF kinematics. The resultant kinematic pathways measured over the entire motion were used to calculate the ROM for each DoF. Results indicate that anterior tilting is the most important DoF of the scapula, the participants all followed similar paths with low variation. Conversely, it appears that protraction/retraction of the scapula is not as important for internally rotating to the back; not only was the ROM the lowest, but the pathways had the highest variation between participants. Regarding glenohumeral motion, internal rotation was by far the DoF with the highest ROM, but there was also high variation in the pathways. Summation of ROM values revealed an average glenohumeral to scapulothoracic ratio of 1.8:1, closely matching the common 2:1 ratio other studies have measured during abduction. Due to the unconstrained nature of the motion, the complex relationship between the glenohumeral and scapulothoracic joints leads to high variation in kinematic pathways. The shoulder has redundant degrees of freedom, the same end position can result from different joint angles and positions. Therefore, some individuals might rely more on scapular motion while others might utilize primarily humeral motion to achieve a specific movement. More analysis needs to be done to identify if any direct correlations can be drawn between scapulothoracic and glenohumeral DoF. Analyzing the kinematics of the glenohumeral and scapulothoracic joint throughout motion will further improve understanding of shoulder mechanics and future work plans to examine differences with age