Total shoulder arthroplasty implants have evolved to include more anatomically shaped components that replicate the native state. The geometry of the humeral head is non-spherical, with the sagittal diameter of the base of the head being up to 6% (or 2.1-3.9 mm) larger than the frontal diameter. Despite this, many TSA humeral head implants are spherical, meaning that the diameter must be oversized to achieve complete coverage, resulting in articular overhang, or portions of the resection plane will remain uncovered. It is suspected that implant-bone load transfer between the backside of the humeral head and the cortex on the resection plane may yield better load-transfer characteristics if resection coverage was properly matched without overhang, thereby mitigating proximal stress shielding. Eight paired cadaveric humeri were prepared for reconstruction with a short stem total shoulder arthroplasty by an orthopaedic surgeon who selected and prepared the anatomic humeral resection plane using a cutting guide and a reciprocating sagittal saw. The humeral head was resected, and the resulting cortical boundary of the resection plane was digitized using a stylus and an optical tracking system with a submillimeter accuracy (Optotrak,NDI,Waterloo,ON). A plane was fit to the trace and the viewpoint was transformed to be perpendicular to the plane. To simulate optimal sizing of both circular and elliptical humeral heads, both circles and ellipses were fit to the filtered traces using the sum of least squares error method. Two extreme scenarios were also investigated: upsizing until 100% total coverage and downsizing until 0% overhang. Total resection plane coverage for the fitted ellipses was found to be 98.2±0.6% and fitted circles was 95.9±0.9%Cortical coverage was found to be 79.8 ±8.2% and 60.4±6.9% for ellipses and circles respectively. By switching to an ellipsoid humeral head, a small 2.3±0.3% (P < 0.001) increase in total coverage led to a 19.5±1.3%(P < 0.001) increase in cortical coverage. The overhang for fitted ellipses and circles was 1.7 ±0.7% and 3.8 ±0.8% respectively, defined as a percentage of the total enclosed area that exceeded the bounds of the humerus resections. Using circular heads results in 2.0 ±0.1% (P < 0.001) greater overhang. Upsizing until 100% resection coverage, the ellipse produced 5.4 ±3.5% (P < 0.001) less overhang than the circle. When upsizing the overhang increases less rapidly for the ellipsoid humeral head that the circular one (Figure 1). Full coverage for the head is achieved more rapidly when up-sizing with an ellipsoid head as well. Downsizing until 0% overhang, total coverage and cortical coverage were 7.5 ±2.8% (P < 0.001) and 7.9 ±8.2% (P = 0.01) greater for the ellipse, respectively. Cortical coverage exhibits a crossover point at −2.25% downsizing, where further downsizing led to the circular head providing more cortical coverage. Reconstruction with ellipsoids can provide greater total resection and cortical coverage than circular humeral heads while avoiding excessive overhang. Elliptical head cortical coverage can be inferior when undersized. These initial findings suggest resection-matched humeral heads may yield benefits worth pursuing in the next generation of TSA implant design. For any figures or tables, please contact the authors directly

The 2021 Australian Orthopaedic Association National Joint Replacement Registry report indicated that total shoulder replacement using both mid head (TMH) length humeral components and reverse arthroplasty (RTSA) had a lower revision rate than stemmed humeral components in anatomical total shoulder arthroplasty (aTSA) - for all prosthesis types and diagnoses. The aim of this study was to assess the impact of component variables in the various primary total arthroplasty alternatives for osteoarthritis in the shoulder. Data from a large national arthroplasty registry were analysed for the period April 2004 to December 2020. The study population included all primary aTSA, RTSA, and TMH shoulder arthroplasty procedures undertaken for osteoarthritis (OA) using either cross-linked polyethylene (XLPE) or non-cross-linked polyethylene (non XLPE). Due to the previously documented and reported higher revision rate compared to other anatomical total shoulder replacement options, those using a cementless metal backed glenoid components were excluded. The rate of revision was determined by Kaplan-Meir estimates, with comparisons by Cox proportional hazard models. Reasons for revision were also assessed. For a primary diagnosis of OA, aTSA with a cemented XLPE glenoid component had the lowest revision rate with a 12-year cumulative revision rate of 4.7%, compared to aTSA with cemented non-XLPE glenoid component of 8.7%, and RTSA of 6.8%. The revision rate for TMH was lower than aTSA with cemented non-XLPE, but was similar to the other implants at the same length of follow-up. The reason for revision for cemented aTSR was most commonly component loosening, not rotator cuff deficiency. Long stem humeral components matched with XLPE in aTSA achieve a lower revision rate compared to shorter stems, long stems with conventional polyethylene, and RTSA when used to treat shoulder OA. In all these cohorts, loosening, not rotator cuff failure was the most common diagnosis for revision

Recent studies have described safe outcomes for short-stays in the hospital after total shoulder arthroplasty. The purpose of this study is to identify pre-operative and operative risk factors for hospital admissions exceeding 24 hours. The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried from 2006 to 2016 for the current procedural terminology (CPT) billing code related to total shoulder arthroplasty. Patients were then grouped as either having a length of stay (LOS) equal to or less than 24 hours or greater than 24 hours. Patients admitted to the hospital prior to the day of surgery were excluded. Patient demographics, co-morbidities, and operative time were then analyzed as risk factors for a hospital stay exceeding 24 hours. Pre-operative co-morbidities included body mass index (BMI), diabetes, smoking, chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), hypertension, dialysis, chronic steroid or immunosuppressant use, bleeding disorders, and American Society of Anesthesiologists (ASA) Classification. Univariate and multivariate analyses were then performed to identify risk factors associated with 30-day readmission. 14,339 patients met inclusion criteria and 6,507 (45.3%) had a hospital LOS less than or equal to 24 hours. The mean length of hospitalization was 1.95 ± 1.88 days, the average age was 69 ± 9.7 years old, and 56.9% of the patients were female. Following a risk adjusted multivariate analysis, increasing age (odds ratio [OR], 1.03, 95% confidence interval [CI], 1.02–1.03), ASA classification (OR, 1.50, 95% CI, 1.41–1.60), diabetes (OR, 1.69, 95% CI, 1.43–1.99), COPD (OR, 1.35, 95% CI, 1.16–1.57), CHF (OR, 2.67, 95% CI, 1.34–5.33), dialysis (OR, 2.47, 95% CI, 1.28, 4.77), history of a bleeding disorder (OR, 1.50, 95% CI, 1.20–1.88), or increasing operative time (OR, 1.01, 95% CI, 1.01–1.01) were identified as independent risk factors for hospital lengths of stay exceeding 24 hours. Male gender was identified as a protective factor for prolonged hospitalization (OR, 0.50, 95% CI, 0.46–0.53). This study identifies patient demographics, co-morbidities, and operative-relative risk factors that are associated with increased risk for a prolonged hospitalization following total shoulder arthroplasty. Female gender, increasing age, ASA classification, operative time, or a history of diabetes, COPD, CHF, or history of a bleeding disorder are risk factors hospitalizations exceeding 24 hours

Although few published papers assess the results of revision total shoulder replacement for painful hemi-arthroplasty with a functional rotator cuff, surgical outcome is accepted as being poor. Our experience suggests that results are poor if a well-fixed humeral stem is revised to correct version, and if a non-functional rotator cuff is not alternatively managed. We identified fifteen patients with painful hemi-arthroplasty and a suspected functional rotator cuff that underwent revision total shoulder replacement at Wrightington hospital over a ten year period. The aetiology comprised osteoarthritis (seven), inflammatory arthritis (five), trauma (two) and avascular necrosis (one). The average time interval to revision surgery was 44.5 months. Humeral head size was up-sized in two and down-sized in seven cases at revision surgery. Three cases underwent iliac crest autografting for glenoid deficiency. Four cases underwent humeral stem revision for incorrect version. The average surgical time for primary total shoulder replacement at Wrightington hospital is 80 minutes while the average time for these revision total shoulder replacements was 105 minutes. Four patients had an unsatisfactory outcome according to Neer’s criteria due to an intra-operative greater tuberosity fracture (one), an intra-operative humeral shaft fracture (one) and a non-functional rotator cuff (two), one of which was revised to an extended head prosthesis with good outcome. Surgical time for revision and primary total shoulder replacement did not differ significantly if humeral stem revision or glenoid augmentation was not indicated. Oversized humeral head components may cause pain due to overstuffing the joint and soft tissues. Revision total shoulder replacement for hemi-arthroplasty with incorrect prosthetic version cannot guarantee an improved outcome. Significant glenoid deficiencies can be effectively managed by iliac crest bone grafting at revision total shoulder replacement. Rotator cuff deficient patients should be managed with alternative prostheses

The infected total shoulder arthroplasty is not a frequent finding at the present time, the necessity of treating this complication may become more urgent with the continually increasing number of arthroplasty procedures performed. From 1992 till the beginning of 2005, eleven patients were treated for infected total shoulder arthroplasty. An acute infection occurred in one patient (9 %), subacute in three (27 %) and late in seven patients (64 %). The average period between the primary operation and infection manifestation was 19.3 months. The group of 181 patients operated on for shoulder replacement between 1992 and 2005 was evaluated, and a deep infection of total shoulder arthroplasty was found in 11 patients (2.2 %). An antibiotic therapy alone was sufficient to eradicate the infeciton in only 20 % of the infected patients, but these showed good Constant scores (average, 42 points). Revision surgery, debridement and irrigation drainage had a low success rate (33 %) and good Constant scores (average, 45 points) in the cured patients. A two-stage exchange was 100 % successful but had a poor outcome, with an average Constant score of 26 points. However, a two-stage exchange involving a spacer had both 100 % success rate and a good outcome with an average Constant score of 49 points. On statistical evaluation using the unpaired t-test, there was a significant difference in the Constant scores (T 4.35 p=0.005) between the patients undergoing exchange arthroplasty with (n=40) and without (n=4) the spacer. Poor function scores after resection arthroplasty are not surprising, because a sharp residual proximal humerus is likely to irritate soft tissues and, in addition, it is not possible to reconstruct a rotator cuff to match it. Comparing the results of one-stage with two-stage reimplantation is a complex issue. Attention should be paid to a relationship between the methods routinely used to treat an infected total shoulder arthroplasty and those preferred by the given hospital for treatment of other joints. If the therapy is well established in that hospital and gives good long-term results, it is optimal to use it also for the treatment of infected total shoulder arthroplasty. The method of treating infected total shoulder arthroplasty is not different from other big joint therapies. The use of a spacer will allow us to remodel soft tissues satisfactorily even after extensive debridement. The functional results of treatment involving a spacer are significantly better

Total shoulder arthroplasty (TSA) and Reverse Total shoulder arthroplasty (RSA) are two of the most performed shoulder operations today. Traditionally postoperative rehabilitation included a period of immobilisation, protecting the joint and allowing time for soft tissue healing. This immobilisation period may significantly impact a patient's quality of life (Qol)and ability to perform activities of daily living (ADL's). This period of immobilisation could be safely avoided, accelerating return to function and improving postoperative QoL. This systematic review examines the safety of early mobilisation compared to immobilisation after shoulder arthroplasty focusing on outcomes at one year. Methods. A systematic review was performed as per the PRISMA guidelines. Results on functional outcome and shoulder range of motion were retrieved. Six studies were eligible for inclusion, resulting in 719 patients, with arthroplasty performed on 762 shoulders, with information on mobilisation protocols on 736 shoulders (96.6%) and 717 patients (99.7%). The patient cohort comprised 250 males (34.9%) and 467 females (65.1%). Of the patients that successfully completed follow-up, 81.5% underwent RSA (n = 600), and 18.4% underwent TSA (n = 136). Overall, 262 (35.6%) patients underwent early postoperative mobilisation, and 474 shoulders were (64.4%) immobilised for a length of time. Immobilised patients were divided into three subgroups based on the period of immobilisation: three, four, or six weeks. There were 201 shoulders (27.3%) immobilised for three weeks, 77 (10.5%) for four weeks and 196 (26.6%) for six weeks. Five of the six manuscripts found no difference between clinical outcomes at one year when comparing early active motion versus immobilisation after RSA or TSA. Early mobilisation is a safe postoperative rehabilitation pathway following both TSA and RSA. This may lead to an accelerated return to function and improved quality of life in the postoperative period

Purpose. Total shoulder arthroplasty (TSA) has become a successful treatment option for degenerative shoulder disease. With the increasing incidence in primary TSA procedures during the last decades, strategies to improve implant longevity become more relevant. Implant failure is mainly associated with mechanical or biological causes. Chronic inflammation as a response to wear particle exposure is regarded as a main biological mechanism leading to implant failure. Metal ions released by fretting and corrosion at modular taper connections of orthopedic implants can cause cell-mediated hypersensitivity reactions and might lead to aseptic loosening. Modularity is also commonly used in total shoulder replacement. However, little is known about metal ion exposure in patients following TSA. The objective of this study was to determine in-vivo blood metal ion levels in patients after TSA and to compare blood metal ion levels to control subjects without metal implants. Methods. A total of 19 patients with anatomical total shoulder prosthesis (TSA group) and 20 patients with reverse total shoulder prosthesis (RSA group) who underwent unilateral total shoulder replacement at our hospital between March 2011 and December 2014 with no other metal implant or history of environmental metal ion exposure were recruited for analysis of blood metal ion concentrations of cobalt (Co), chromium (Cr) and titanium (Ti) at a mean follow-up period of 2.3 years (0.7–4.3). For comparison of metal ion concentrations blood samples were obtained in a healthy control group of 23 subjects without metal implants. Ethical approval and informed consent of each patient were obtained for this study. Results. Median cobalt ion levels were 0.14µg/l (range 0.03–0.48) in the TSA group, 0.18 µg/l (0.10–0.66) in the RSA group and 0.11µg/l (0.03–0.19) in the control goup. Median chromium ion levels were 0.34µg/l (0.09–1.26) in the TSA group, 0.48µg/l (0.17–2.41) in the RSA group and 0.14µg/l (0.04–0.99) in the control goup. Median titanium ion levels were 0.86µg/l (0.10–1.64) in the TSA group, 1.31µg/l (0.75–4.52) in the RSA group and 0.62µg/l (0.32–2.14) in the control goup. There was a statistically significant difference in chromium and titanium ion concentrations between both study groups and the control group (see figure 1–3). Conclusion. Patients with unilateral total shoulder replacement demonstrated elevated blood metal ion concentrations. Median blood metal ion levels were higher in the RSA group compared to the TSA group, which could be attributable to the modularity of the reverse total shoulder system. However, overall metal ion levels were relatively low compared to those seen in patients with metal-on-metal total hip replacements. The role of local metal ion exposure in the development of aseptic loosening or hypersensitivity reactions associated with total shoulder arthroplasty should be further investigated. For figures/tables, please contact authors directly.

Background. Tranexamic acid is an antifibrinolytic drug that has been shown to successfully reduce postoperative blood loss in total knee and hip arthroplasty. However, the efficacy of TXA following total shoulder arthroplasty has not been reported. Purpose. The purpose of the present study was to evaluate the impact of intravenous TXA on postoperative blood loss and transfusion rates in total shoulder reconstruction. Methods. Between July and December 2014, 50 patients scheduled for primary total shoulder arthroplasty of the shoulder were included in this blinded, randomized study. Patients received either 1000mg intravenous TXA within thirty minutes before skin incision and another 1000mg intravenously administered TXA during wound closure (group 1), or a placebo (group 2). The perioperative blood loss and the rate of blood transfusions were analyzed. Results. Early postoperative blood loss was 80.0±105.5ml in the TXA group (group 1), and 202.1±195.8ml in the placebo group (group 2). The administration of blood products was not necessary during the study period. Conclusion. The administration of intravenous tranexamic acid significantly reduced the postoperative blood loss following total shoulder arthroplasty

Introduction and Objective. Total shoulder replacement is a common elective procedure offered to patients with end stage arthritis. While most patients experience significant pain relief and improved function within months of surgery, some remain unsatisfied because of residual pain or dissatisfaction with their functional status. Among these patients, when laboratory workup eliminates infection as a possibility, corticosteroid injection (CSI) into the joint space, or on the periprosthetic anatomic structures, is a common procedure used for symptom management. However, the efficacy and safety of this procedure has not been previously reported in shoulder literature. Materials and Methods. A retrospective chart review identified primary TSA patients who subsequently received a CSI into a replaced shoulder from 2011 – 2018 by multiple surgeons. Patients receiving an injection underwent clinical exam, laboratory analysis to rule out infection, and radiographic evaluation prior to CSI. Demographic variables were recorded, and a patient satisfaction survey assessed the efficacy of the injection. Results. Of the 43 responders, 48.8% remembered the injection. The average time from index arthroplasty to injection was median 16.8 months. Overall, 61.9% reported decreased pain, 28.6% reported increased motion, and 28.6% reported long term decreased swelling. Improvement lasted greater than one month for 42.9% of patients, and overall 52.4% reported improvement (slight to great) in the shoulder following CSI. No patient developed a periprosthetic joint infection (PJI) within 2 years of injection. Conclusions. This study suggests that certain patients following TSA may benefit from a CSI. However, this should only be performed once clinical, radiographic, and laboratory examination has ruled out conditions unlikely to improve long term from a CSI. Given these findings, further study in a large, prospective trial is warranted to fully evaluate the benefits of CSI following TSA

Management of arthropathy of the glenohumeral joint has undergone an evolution from neglect to arthrodesis to arthroplasty over the past 30 years. Indications for total shoulder arthroplasty include severely symptomatic glenohumeral arthritis resulting from rheumatoid arthritis, osteoarthritis, a variety of inflammatory arthropathies, post-traumatic arthritis, chronic or multiple recurrent dislocation arthropathy, cuff tear arthropathy and even septic arthritis. Each form of arthropathy has its own special indications and nuances regarding the successful performance of arthroplasty. With good bone stock and a healthy soft tissue envelope (comprised of deltoid, scapula support musculature and rotator cuff tendons), resurfacing of both the proximal humerus and glenoid has proven to be a very successful surgical procedure, affording reduction in pain, improved motion and function. This procedure has undergone an evolution from the early prosthesis designed by Dr. Charles Neer to the many modular prosthetic devices now available, providing the capability to closely resemble native anatomy in the form of size, version, and angulation. Although the prostheses themselves focus on the restoration of articular surfaces, the key to a successful operation lies in the appropriate tensioning of the soft tissues and recreation of a functional dynamic soft tissue envelope. When bone stock is limited (most commonly involving the glenoid or the glenoid neck), hemiarthroplasty with or without fascial resurfacing of the glenoid has been shown to be helpful. In cuff deficient patients mobilisation and transfer of tendons around a hemiarthroplasty to provide stability and limited motion has proven to be a good alternative to total shoulder replacement. In the face of infection, debridement and staged reconstruction using an antibiotic impregnated methacrylate spacer with later exchange for a hemi- or total shoulder arthroplasty has been a successful solution and alternative to arthrodesis. Resection arthroplasty and/or arthrodesis are rarely indicated in the active individual but may prove to be viable “bail out” procedures in the patient with chronic infection, low demand or deltoid paralysis. Arthroscopic debridement of a moderately arthritic joint in young patients has recently been described but its long-term efficacy and has yet to be demonstrated. Participants should take away from this session an understanding of the indications and contraindications for total shoulder arthroplasty as well as appropriate alternatives in a variety of challenging clinical entities

Arthroplasty implant modularity enables the surgeon to adapt the joint replacement construct to the patient's requirements, and often facilitates revision procedures. Total shoulder arthroplasty humeral modularity exists for many implant systems. Glenoid modularity with convertibility between anatomic and reverse shoulder arthroplasty is a recent development. Glenoid modularity is very useful when reconstructing glenoid bone deficiencies, or in providing a method for reverse shoulder arthroplasty joint lateralization. The live surgery will demonstrate a bio-reverse total shoulder arthroplasty (bRTSA). The humeral component is a modular press fit stem that can accommodate either reverse or anatomic metaphyseal components. The metaphyseal components can be exchanged without removing the stem or changing the humeral height. The glenoid base has three components. The trabecular titanium peg is available in two diameters, and four lengths for each diameter. The peg is fixed to a metal base plate via Morse taper. In revision settings, these components can be easily dissociated in situ, and a coring drill inserted over a well-fixed peg allows removal with minimal bone loss. Either a polyethylene component, or glenosphere can be attached to the baseplate to complete the glenoid construct. An innovative set of instruments have been developed to reliably prepare the glenoid and humeral bone graft. While the live surgery will demonstrate the grafting technique in a bRTSA, it can also be used to reconstruct glenoid deficiencies (eg, Walch B2). Implants have been developed to solve these issues, but often do so at the expense of very limited glenoid bone stock. Bone grafting actually creates a net increase in glenoid bone stock that may improve implant durability, and decrease revision complexity. The technique is quite simple and adds approximately ten minutes to operative time. I have used this technique for 5 years with no cases of graft failure

Background. While total shoulder arthroplasty (TSA) is a generally successful procedure, glenoid loosening remains a common complication. Though the occurrence of loosening was related to patient-specific factors, biomechanical factors related to implant features may also affect the fixation of the glenoid component, in particular increased glenohumeral mismatch that could result in eccentric loads and translations. In this study, a novel test setup was used to quantify glenohumeral pressures for different motion patterns after TSA. Methods. Six cadaveric human shoulders were implanted with total shoulder replacements (Exactech, Inc., USA) and subjected to cyclic internal-external, flexion-extension and abduction-adduction rotations in a passive motion testing apparatus. The system was coupled to a pressure sensor system (Tekscan, Inc., USA) to acquire joint loads and to a Zebris system (Zebris Medical, GmbH, Germany) to measure joint kinematics. The specimens were subjected to a total of 2160 cycles and peak pressures were compared for each motion pattern. Results. It was shown that during abduction the contact area between the humeral head and the glenoid component shifts from a posterior to an anterior position, while also moving inferiorly. For internal-external rotation a mean peak pressure of 8.37 ± 0.22 MPa was registered, while for flexion-extension a pressure of 9.37 ± 0.38 MPa and for abduction-adduction a pressure of 9.88 ± 0.07 MPa were obtained. Conclusion. This study showed how glenohumeral pressures after TSA vary during simulated internal-external, flexion-extension and abduction-adduction rotations in a cyclic testing setup. It showed that peak loads are mainly obtained in abduction, and that these occurred mainly near the anterior part of the glenoid. Future steps involve implantation of other type of anatomical glenoid components to obtain different levels of glenohumeral mismatch and relating the 3D measurements of motion patterns to contact pressures

Between January 1, 1976 and December 31, 1991, 195 total shoulder arthroplasties and 108 hemiarthroplasties were performed by the senior author in patients with rheumatoid arthritis. One hundred eighty-seven total shoulder arthroplasties and 95 hemiarthroplasties with complete preoperative evaluation, operative records, and minimum 2-year follow-up (mean 11.6 years) or follow-up until revision were included in the clinical analysis. Twenty patients died and one was lost to follow-up. All 303 shoulders were included in the survival analysis. There was significant long term pain relief (P< .0001), improvement in active abduction (P< .0001), and external rotation (P< .0001) with both, hemiarthroplasty and total shoulder arthroplasty. There was not a significant difference in improvement in pain and motion comparing hemiarthroplasty and total shoulder arthroplasty for patients with a thin or torn rotator cuff. However, among patients with an intact rotator cuff, improvement in pain and abduction were significantly greater with total shoulder arthroplasty. Additionally, among patients with an intact rotator cuff, the risk for revision was significantly lower for total shoulder arthroplasty (p=0.04). Radiographs were available for 152 total shoulder arthroplasties and 63 hemiarthroplasties with a minimum 2 year follow-up. Glenoid erosion was present in 62 of 63 hemiarthroplasties (98%). Glenoid periprosthetic lucency was present in 110 of 152 total shoulder arthroplasties (72%). The data from this study indicate there is marked long term pain relief and improvement in motion with shoulder arthroplasty. Among patients with an intact rotator cuff, total shoulder arthroplasty appears to be the preferred procedure for pain relief, improvement in abduction, and lower risk of revision surgery

In shoulder arthroplasty the glenoid component remains a problem. Hemi-arthroplasty requires less theatre time and gives rise to fewer complications. The question is whether the results of hemi-arthroplasty are inferior to those of total shoulder arthroplasty. We assessed 189 patients who since July 1994 had undergone hemi-arthroplasty or total shoulder arthroplasty, excluding patients who suffered fractures, malunion or nonunion. In 77 patients (41%) the glenoid was replaced. The mean age of patients was 62 years. All humeral and glenoid components were cemented. Preoperative and postoperative assessments included pain (visual analogue scale), muscle strength, range of motion, functional activities and Constant shoulder scores. At this early stage, total shoulder arthroplasty appears to give slightly better functional results than hemi-arthroplasty. However, there were five (6.5%) complications associated with the glenoid components, including glenoid component fracture, loosening and migration. Hemi-arthroplasty eliminates concerns about glenoid wear and glenoid complications, and we believe total shoulder arthroplasty should be reserved for specific problems

Introduction The complex movement of scapula is significant for the support of the arm and the stability of the shoulder joint. Recent investigations showed an adaptation in scapula rhythm after total shoulder replacement with a big variability within subjects. The latter can change the loading pattern in the glenohumeral contact forces and affect the performance of shoulder prosthesis. Methods In this study, Newcastle shoulder model was used to simulate a total shoulder arthroplasty and investigate joint stability. The model describes the DELTA . ®. prosthesis; a reverse anatomy design with a socket component attached to the humeral head and a hemi-ball to the glenoid. Scapula kinematics data of 6 shoulders were recorded using a palpating technique. The subjects had a total shoulder replacement after severe rotator cuff damage. Standard and daily activities were then analysed. Results and Discussion Scapula kinematics data show an increased scapular lateral rotation, which influences the joint contact forces. Comparing contact forces on the Glenohumeral joint, results indicate that the scapula rhythm adaptation reduces the compressive forces and shifts the shear component more superiorly to the glenoid. The scapula rhythm data used in this study show a large variability, which also affect the loading results. This effect is more significant in “reaching tasks”, where high humeral elevation is required and joint contact loads are maximum. The anterior shear forces in these tasks can be as great as 19% of body weight. Conclusions The adaptation in scapulohumeral rhythm after a shoulder joint replacement has already been reported. The reason for this adaptation cannot be explained yet and may be pain related or due to muscle adaptation that takes place after the arthroplasty. This change in kinematics influences the loading pattern of the glenohumeral joint. In particular the increased shear forces must be taken into considered in prosthetic design

Over the last decade stemless shoulder arthroplasty has become increasingly popular. However, stability of metaphyseal loading humeral components remains a concern. This study aimed to assess the stability of the Affinis stemless humeral component using Radiostereometric analysis (RSA). Patients underwent total shoulder arthroplasty via a standardised technique with a press-fit stemless humeral component and a cemented pegged glenoid. Tantalum beads were inserted into the humerus at the time of operation. RSA of the relaxed shoulder was completed at weeks 1, 6, 13, 26, 52 and 104 post-operatively. Stressed RSA with 12 newtons of abduction force was completed from week 13 onwards. ABRSA 5.0 software (Downing Imaging Limited, Aberdeen) was used to calculate humeral component migration and induced movement. 15 patients were recruited. Precision was: 0.041, 0.034, 0.086 and 0.101 mm for Superior, Medial, Posterior and Total Point Motion (TPM) respectively. The mean TPM over 2 years was 0.24 (0.30) mm, (Mean (Standard deviation)). The mean rate of migration per 3 month time period decreased from 0.45 (0.31) to 0.02 (0.01) mm over 2 years. Mean inducible movement TPM peaked at 26 weeks at 0.1 (0.08) mm, which reduced to 0.07 (0.06) mm by 104 weeks when only 3 patients had measurable inducible motion. There was no clear trend in direction of induced movement. There were no adverse events or revisions required. We conclude migration of the humeral component was low with little inducible movement in the majority of patients implying initial and 2 year stability of the stemless humeral component

INTRODUCTION. Mechanically assisted crevice corrosion of taper interfaces was raised as a concern in total hip arthroplasty (THA) approximately 20 years ago (Gilbert 1993). In total shoulder replacement, however, comparatively little is known about the prevalence of fretting assisted crevice corrosion or the biomechanical and patient factors that influence this phenomenon. Given the comparatively lower loading experienced in the shoulder compared to the hip, we asked: (1) What is the prevalence of fretting assisted corrosion in modular total shoulder replacements, and (2) What patient and implant factors are associated with corrosion?. METHODS. Modular components were collected from 48 revision shoulder arthroplasties as part of a multi-center, IRB approved retrieval program. For anatomic shoulders, this included 40 humeral heads, 32 stems and four taper adapters from seven manufacturers. For reverse shoulders, there were eight complete sets of retrieved components from three manufacturers. The components were predominantly revised for instability, loosening and pain. Anatomical shoulders were implanted for an average of 3.1 years (st dev 3.8; range 0.1–14.5). Reverse shoulders were implanted for an average of 2.2 years (st dev 0.7; range 1.3–3.3). Modular components were disassembled and examined for taper damage. The modular junctions were scored for fretting corrosion using a semi-quantitative four-point scoring system adapted from Goldberg, et al. (Goldberg, 2002, Higgs 2013). The scoring system criteria was adapted from Goldberg and Higgs which is comprised of a one to four grading system (with one indicating little-to-no fretting/corrosion and four indicating extensive fretting/corrosion). The component alloy composition was determined using the manufacturer's laser markings and verified by x-ray fluorescence. Patient age, gender, hand dominance, alloy, flexural rigidity of the trunnion and taper geometry were assessed independently as predictors for fretting corrosion. RESULTS. Moderate to severe fretting corrosion (score > 2) was observed in 23% of the anatomic modular components (Figure 1) and 22% of the reverse shoulder components. An example with severe damage is included in Figure 1. There was no significant relation between corrosion scores and any of the assessed factors. DISCUSSION AND CONCLUSION. It has been suggested that fretting assisted crevice corrosion may be a concern in THA, particularly with large head metal-on-metal articulations. We have identified the presence of moderate to severe corrosion on approximately one quarter of all retrieved shoulder arthroplasties. This is similar to the proportion observed in retrieved modular hips (Goldberg, 2002). While the expected loading of the shoulder is less than that in the hip (Westerhoff, 2009), the offset between the effective center of the prosthetic humeral head and the taper connecter is often larger and the size of the taper is smaller. This can increase the effect of bearing surface loading on the taper. We were unable to detect significant associated biomechanical or patient factors. This was probably due to the limited sample size of our population. At the present time, the clinical effects of taper corrosion in shoulder arthroplasty remain unknown

Abstract. Objectives. Routine blood test following total shoulder arthroplasty (TSA) cost the NHS more than £72000 in 2018 without definite evidence of their impact on patients’ management or outcomes. This study aimed to ascertain if routine laboratory tests are a necessity post TSA or can be implemented on a per-patient. Methods. A retrospective review of the electronic records completed for 251 patients underwent TSA over 6 years. 193 patients were eligible for analysis. Primary outcomes were interventions to the abnormal postoperative blood tests. Secondary outcomes were the length of stay (LOS), and readmission within 30 days and 90 days. Results. 193 patients underwent 216 TSAs; 72 % were females and 18% males. The mean age was 78 ± 7.2 years. Completed procedures included 134 reverse, 64 anatomical and 18 revision TSAs. 136 patients (63%) had an abnormal postoperative blood test, however, only 8 (3.7%) required intervention. The average postoperative haemoglobin (Hb) drop was 19 g/L with 94 patients (43.5%) having Hb <109g/L. 4 patients (1.8%) dropped Hb < 80g/L; only 2 patients (0.9%) were symptomatic and received RBC transfusion . 6 patients (2.8%) developed acute kidney injury and treated by IV fluids. The mean LOS was 3.2 ± 2.9 days .5 patients (2.3%) were readmitted within 30 days and 6 patients (2.8%) within 90 days. Univariate analysis showed association only between abnormal Creatinine and LOS (p<0.05) and of these patients, all had abnormal preoperative Creatinine baseline. No statistical correlation detected between age (p=0.287), postoperative Hb (p=0.230) and LOS nor readmission at 30 or 90 days. Conclusions. Routine postoperative blood tests are not required as they have not shown to produce a meaningful clinical impact in this cohort of patients nor on the re-admission rate, causing unnecessary costs. We recommend assessing each patient and request for investigations in a coherent and justified manner. 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

Introduction. Postoperative total shoulder arthroplasty (TSA) blood tests cost the National Health Service in the UK more than £72000 annually without definite evidence of their impact on outcomes. This study aimed to ascertain if these blood tests can be implemented on a per-patient basis. Methods. A retrospective review of one centre TSA patients over 6 years. Primary outcomes were interventions to abnormal postoperative blood tests. Secondary outcomes were the length of stay (LOS), and readmission within 30 and 90 days. Results. 193 patients underwent 216 TSAs; 72 % were females and 18% males. The mean age was 78 ± 7.2 years. Completed procedures included 134 reverse, 64 anatomical and 18 revision TSAs. 136 patients (63%) had an abnormal postoperative blood test, however, only 8 (3.7%) required intervention. The average postoperative Hb drop was 19 g/L with 94 patients (43.5%) having Hb <109g/L. 4 patients (1.8%) dropped Hb < 80g/L; only 2 (0.9%) were symptomatic and received RBC transfusion. 6 patients (2.8%) developed acute kidney injury and treated by IV fluids. The mean LOS was 3.2 ± 2.9 days .5 patients (2.3%) were readmitted within 30 days and 6 patients (2.8%) within 90 days. Univariate analysis showed association only between abnormal Creatinine and LOS (p<0.05) and of these patients, all had abnormal preoperative Creatinine baseline. No statistical correlation detected between age (p=0.287), postoperative Hb (p=0.230) and LOS nor readmission at 30 or 90 days. Conclusions. Routine postoperative blood tests are not required as no detected meaningful clinical impact and should be requested on an individual justified basis

Aim. Cutibacterium acnes (C. acnes) is the most cultured organism implicated in periprosthetic shoulder infections. Nevertheless, the clinical significance of its persistence on the skin surface and in the deep layers during shoulder arthroplasty surgery remains still unknown. The purpose of this study was to know if the C. acnes isolate present in deep tissues at the end of a primary shoulder arthroplasty could be responsible for shoulder arthroplasty infection. Method. Prospective study including 156 patients undergoing primary shoulder arthroplasty. In all the patients included 5 to 12 tissue samples were obtained and were specifically cultured to detect C. acnes presence. DNA was extracted from the C. acnes colonies selected with the QIAsymphony DSP Virus/Pathogen Midi Kit (Qiagen, Hilden, Germany). Libraries were prepared using Nextera XT kit (Illumina) and sequenced in an Illumina MiSeq sequencer. Sequencing files were pre-processed using The Microbial Genome Atlas pipeline. Samples that failed on QC analysis were discarded for further analysis. Isolate nucleotide distances were calculated using Genome-based distance matrix calculator from the enveomics collection. Comparative genomic analysis was performed between intra- and inter-patients’ isolates. Data analysis was performed using R 3.6.3. Results. For twenty-seven out of 156 patients (17.31%), C. acnes was present at the end of the primary surgery. Two of these patients (both male) developed a C. acnes periprosthetic shoulder infection after 6 and 4 months from the primary surgery. DNA from the C. acnes responsible for the periprosthetic infection was further analysed by whole genome sequencing (WGS). Average Nucleotide Identity (ANI) value was assessed, measuring the nucleotide-level genomic similarity between genome pairs. We found a clear ANI clustering in two major groups which corresponded, mainly, to the associated phylotype (97%–98% ANI). Moreover, when analysing both isolates that developed a periprosthetic shoulder infection, we found that all the revision-surgery isolates clustered nearer to their corresponding primary-surgery isolates (99.4% of similarity) than to the other independent bacterial isolates, supporting the causal relationship between the initial and the delayed infection. Conclusions. C. acnes present at the end of the primary surgery can be the cause of early- or delayed-periprosthetic joint infections in shoulder arthroplasty, revealing the potential route of infection. Therefore, efforts must be made in terms of antibiotic prophylaxis and skin preparation to limit infections of total shoulder arthroplasties