Introduction. Initial fixation of noncemented implants is critical to achieve a stable bone/implant interface during the first few months after surgery to potentiate bone in-growth and avoid aseptic loosening. Numerous reverse shoulder glenoid implant designs have been conceived in an attempt to improve implant performance and decrease the rate of aseptic glenoid loosening, commonly reported to be 5%. Design variations include: baseplate profile, baseplate size, backside geometry, center of rotation, surface finish and coatings, fixation screw diameters, number of fixation screw options, and type of screw fixation. However, little comparative biomechanical data exist to substantiate one design consideration over another. To that end, this study quantified glenoid fixation before and after cyclic loading of simulated abduction of 6 different reverse shoulder glenoid designs when secured to a low density polyurethane bone substitute block. Methods. A displacement test quantified fixation of 6 different reverse shoulder designs: 38 mm Equinoxe standard offset (EQ), 38 mm Equinoxe lateral offset (EQL), 36 mm Depuy Delta III (DRS), 36 mm Zimmer, (ZRS), 32 mm neutral DJO RSP (DJO), and a 36 mm Tornier BIO-RSA (BIO), secured to a 0.24 g/cm. 3. polyurethane block as a shear (357 N) and compressive (50 N) load was applied before and after cyclic loading. (Figure 1) Glenoid displacement was measured relative to the block using dial indicators in the directions of the applied loads along the superior/inferior axis. A cyclic test rotated each glenosphere (n = 7 for each design) about a 55° arc of abduction at 0.5 Hz for 10k cycles as 750N was constantly applied. (Figure 2) Each implant was cycled using a 145° humeral liner of the appropriate diameter to ensure each device is subjected to the same shear load. A two-tailed unpaired student's t-test was used to compare pre- and post-cyclic mean displacements between designs; p < 0.05 denotes significance. Results. The average pre-cyclic displacement of the EQ, EQL, DRS, ZRS, DJO, and BIO devices was 181, 137, 186, 381, 238, 232 microns, respectively. The average post-cyclic displacement of the EQ, EQL, DRS, DJO, and BIO devices was 186, 129, 189, 368, 249 microns, respectively. During the cyclic test, 6 of 7 ZRS devices failed at an average of 2603 cycles, 1 of 7 DJO failed at 7342 cycles, and 4 of 7 BIO devices failed at an average of 2926 cycles. All 7 of the EQ, EQL, and DRS devices remained well fixed throughout cyclic loading. Discussion and Conclusions. The results of this study demonstrate significant difference in fixation associated 6 different reverse shoulder designs. Despite many similarities in geometry between these designs, significant differences in fixation were observed between nearly every implant design tested. This suggests that subtle changes in glenoid baseplate design can dramatically impact fixation, particularly in low density bone substitutes which are intended to simulate the bone quality of the recipient population for reverse shoulders. Future work should attempt to isolate which design parameters are the most critical contributors for initial fixation and ultimately, long-term stability

Introduction. The use of reverse total shoulder arthroplasty (RSA) is becoming increasingly common in the treatment of rotator cuff arthropathy. Standard RSA technique involves medialising the centre of rotation (COR) maximising the deltoid lever arm and compensating for rotator cuff deficiency. However reported complications include scapular notching, prosthetic loosening and loss of shoulder contour. As a result the use of Bony Increased Offset Reverse Shoulder Arthroplasty (BIO-RSA) has been gaining in popularity. The BIO-RSA is reported to avoid these complications by lateralising the COR using a modified base plate, longer central post and augmentation with cancellous bone graft harvested from the patients humeral head. Objectives. This study aims to compare the outcome in terms of analgesic effect, function and satisfaction, in patients treated with standard RSA and BIO-RSA. Methods. All cases were performed in a single centre by one of two upper limb consultant orthopaedic surgeons over a consecutive 2-year period. At time of listing for operation, the decision as to whether to undertake a bony-increased offset reverse total shoulder was made. Standard deltopectoral approach was performed. Standard and Bony increased offset Tournier reverse was the implant of choice (BIO-RSA). All patients underwent a standardised rehabilitation programme. Standard follow up was clinical review with radiographs at 2 weeks, 6weeks and 3months. Retrospective data was collected using case notes on patient reported stausfaction and oxford shoulder score, analgesia requirement at final follow up, and final range of movement. Results. A total of 60 patients (65 shoulders) were treated with reverse total shoulder replacements (RSA) within a 2-year period in a single centre for chronic complex shoulder conditions. Mean age at time of intervention was 74.1years (49.3 – 88.7). Mean follow up was 7.1 months (3.4 – 24). Average time to discharge 16.1 months (3.4 – 37.4). 43 patients currently under review. Of the 65 shoulders, 40 underwent BIO-RSA procedures. Indications for surgery were predominantly rotator cuff arthropathy (N=36). Other indications included severe osteoarthritis (N=1) and complex proximal humeral fracture (N=3). The remaining 25 patients treated with standard RSA were similar in terms of indication and basic demographics. In terms of range of movement, outcomes between the two groups were broadly similar. Patients receiving BIO-RSA demonstrated mean active forward flexion of 92.2° (70–120°) and abduction 93.3° (80–120°). The RSA group had mean forward flexion 90.5° (50–130°) and mean abduction 88.6° (40–160°). Both groups had excellent analgesic effect with 92% in each either being completely pain free or requiring only occasional analgesia. The majority of patients were either very satisfied or satisfied with the outcome of the surgery. Mean Oxford shoulder score for the BIO-RSA group was 4.9 (0–13) preoperatively and 43.7 (36–48) postoperatively. The mean RSA pre-operative score was 7.9 (0–19) and postoperatively 40.2(32–48). In total three patients experienced complications; 1 haematoma (BIO-RSA), 1 brachial plexus contusion (BIO-RSA) and 1 deep infection (RSA). Conclusion. If grafting is necessary, the use of BIO-RSA within this centre seems to have comparable results to those undergoing standard RSA. Early results also suggest the Bio-RSA allows earlier improvement and conserves a larger bone stock. These early result are encouraging however a further study with longer follow-up is required

Background. Locked anterior shoulders (LAS) with static instability and anterior glenoid bone loss are challenging in the elderly population. Reverse shoulder arthroplasty (RSA) has been employed in treating these patients. No study has compared RSA for LAS to classically indicated RSA. Methods. A case-control study of patients treated with RSA for LAS with glenoid bone loss and static instability was performed using matched controls treated with primary RSA for classic indications. Twenty-four cases and 48 controls were evaluated. Average follow-up was 25.5 months and median age was 76. Motion, outcome assessments, and postoperative radiographs were compared. Results. Preoperatively, LAS had significantly less rotation and lower baseline outcome scores. Glenoid bone grafting was more common (p=0.05) in control group (26%) than LAS group (6.3%). Larger glenospheres were utilized more often (p=0.001) in LAS group (75%) than control group (29%). Both groups demonstrated significant improvements in pain, function, and outcome scores. Postoperatively, control group had significantly better elevation and functional outcome scores. With the exception of flexion and SST, effectiveness of treatment was similar between groups. Postoperative acromion stress fractures were seen in 21% of LAS and 9% of control (p=0.023) with a predominance of type 3 fractures in LAS. Two LAS patients remained dislocated. Conclusion. Treatment with RSA for LAS may anticipate improvements in pain and function using larger glenospheres often without the need for glenoid bone grafting. Worse postoperative motion, function, and a higher incidence of acromion stress fracture may be expected

Reverse shoulder arthroplasty is becoming a frequent treatment of choice for patients with shoulder disorders. Complication rates after reverse shoulder arthroplasty may be three-fold that of conventional total shoulder arthroplasty especially in high risk patient populations and diagnoses like revision arthroplasty, fracture sequelae, and severe glenoid bone loss. Complications include component malposition, stiffness, neurological injury, infection, dislocation or instability, acromial or scapular spine fractures, scapular notching, and loosening of implants. Recognition of preoperative risk factors and appropriate 3D planning are essential in optimizing patient outcome and intraoperative success. Failure of reverse shoulder arthroplasty is a significant challenge requiring appropriate diagnosis of the failure mode. The most common neurological injuries involve the brachial plexus and the axillary nerve due to traction, manipulation of the arm, aberrant retractor placement, or relative lengthening of the arm. Intraoperative fractures are relatively uncommon but include the greater tuberosity, acromion, and glenoid. Tuberosity fracture can be repaired intraoperatively with suture techniques, glenoid fractures may be insignificant rim fractures or jeopardise baseplate fixation and require abandoning RSA until glenoid fracture ORIF heals and then a second stage RSA. Periprosthetic infection after RSA ranges from 1 to 10% and may be higher in revision cases and frequently is Propionibacterium acnes and Staphylococcus epidermidis. Dislocation was one of the most common complications after RSA approximately 5% but with increased surgeon experience and prosthetic design, dislocation rates are approaching 1–2%. An anterosuperior deltoid splitting approach has been associated with increased stability as well as subscapularis repair after RSA. Scapular notching is the most common complication after RSA. Notching may be caused by direct mechanical impingement of the humerosocket polyethylene on the scapular neck and from osteolysis from polyethylene wear. Sirveaux classified scapular notching based on the defect size as it erodes behind the baseplate towards the central post. Acromial fractures are infrequent but more common is severely eroded acromions from CTA, with osteoporosis, with excessive lengthening, and with superior baseplate screws that penetrate the scapular spine and create a stress riser. Nonoperative care is the mainstay of acromial and scapular spine fractures. Recognizing preoperative risk factors and understanding component positioning and design is essential to maximizing successful outcomes

Scapular notching is a common problem following reverse shoulder arthroplasty (RSA). This is due to impingement between the humeral polyethylene cup and scapular neck in adduction and external rotation. Various glenoid component strategies have been described to combat scapular notching and enhance impingement-free range of motion (ROM). There is limited data available detailing optimal glenosphere position in RSA with an onlay configuration. The purpose of this study was to determine which glenosphere configurations would maximise impingement free ROM using an onlay RSA prosthesis. A three-dimensional (3D) computed tomography (CT) scan of a shoulder with Walch A1, Favard E0 glenoid morphology was segmented using validated software. An onlay RSA prosthesis was implanted and a computer model simulated external rotation and adduction motion of the virtual RSA prosthesis. Four glenosphere parameters were tested; diameter (36mm, 41mm), lateralization (0mm, 3mm, 6mm), inferior tilt (neutral, 5 degrees, 10 degrees), and inferior eccentric positioning (0.5mm, 1.5mm. 2.5mm, 3.5mm, 4.5mm). Eighty-four combinations were simulated. For each simulation, the humeral neck-shaft angle was 147 degrees and retroversion was 30 degrees. The largest increase in impingement-free range of motion resulted from increasing inferior eccentric positioning, gaining 15.0 degrees for external rotation and 18.8 degrees for adduction. Glenosphere lateralization increased external rotation motion by 13. 6 degrees and adduction by 4.3 degrees. Implanting larger diameter glenospheres increased external rotation and adduction by 9.4 and 10.1 degrees respectively. Glenosphere tilt had a negligible effect on impingement-free ROM. Maximizing inferior glenosphere eccentricity, lateralizing the glenosphere, and implanting larger glenosphere diameters improves impingement-free range of motion, in particular external rotation, of an onlay RSA prosthesis. Surgeons’ awareness of these trends can help optimize glenoid component position to maximise impingement-free ROM for RSA. Further studies are required to validate these findings in the context of scapulothoracic motion and soft tissue constraints

There is a large and growing population of patients with shoulder arthritis that are over 70 years old. Many of these patients live alone and sling immobilization after shoulder arthroplasty is problematic. Other than improved internal rotation, there are limited benefits of anatomic shoulder arthroplasty compared to reverse arthroplasty. Anatomic arthroplasty is associated with longer OR time, longer recovery with need for assistance to allow the subscapularis to heal, and more challenging glenoid exposure. The reverse arthroplasty is a faster operation without the need for subscapularis healing and the sphere provides a more forgiving implant position. Additional benefits of reverse arthroplasty include better ability to manage glenoid bone loss and joint subluxation. Data from the Australian Orthopaedic Association National Joint Replacement Registry shows that within the first year of surgery the rate of revision of anatomic shoulder arthroplasty is less than reverse arthroplasty. However, after one year, the overall revision rate of reverse arthroplasty is less than anatomic shoulder arthroplasty. Therefore, increased technical difficulty of anatomic shoulder arthroplasty together with concerns of subscapularis insufficiency, glenoid loosening, and lack of strong evidence of superiority do not warrant changing from reverse for patients over 70 years old

The treatment of proximal humerus fractures remains controversial. The literature is full of articles and commentary supporting one method over another. Options include open reduction and internal fixation, hemiarthroplasty, and reverse shoulder arthroplasty. Treatment options in an active 65-year-old are exceptionally controversial given the fact that people in this middle-aged group still wished to remain active and athletic in many circumstances. A hemiarthroplasty offers the advantage of a greater range of motion, however, this has a high incidence of tuberosity malunion or nonunion and this is a very common reason for revision of that hemiarthroplasty for fracture to a reverse shoulder replacement. One recent study showed a 73% incidence of tuberosity malunion or nonunion in shoulders that had a revised hemiarthroplasty to a reverse shoulder replacement. Progressive glenoid wear and erosion is also a risk after a hemiarthroplasty in the younger patient, especially someone who is young and active. In addition, studies show shorter operative time in hemiarthroplasty. The range of motion is highly dependent on proper tuberosity healing and this is often one of the most challenging aspects of the surgical procedure as well as the healing process. A reverse shoulder replacement in general has less range of motion compared to a hemiarthroplasty with anatomically healed tuberosities, however, the revision rate is lower compared to a hemiarthroplasty. (This is likely related to few were options for revision). The results after a reverse shoulder replacement may not be as dependent on tuberosity healing, however, importantly the tuberosities do need to be repaired and the results are significantly better if there is healing of the greater tuberosity, giving some infraspinatus and/or teres minor function to the shoulder. Complete lack of tuberosity healing forces the shoulder into obligate internal rotation with attempted elevation and this can be functionally disabling. Academic discussion is beginning surrounding the use of a reverse shoulder replacement in the setting of glenohumeral joint arthritis in a primary setting as it is believed that the glenosphere and baseplate may have greater longevity than a polyethylene glenoid. Along with this discussion, we will likely see greater application of the use of a reverse shoulder replacement in the setting of fracture for younger patients. In general, open reduction internal fixation should still remain the treatment of choice in the setting of a fracture that can be fixed. However, a strong argument can be made that if an arthroplasty is necessary, a reverse shoulder replacement is the implant of choice

Severe glenoid bone loss in patients with osteoarthritis with intact rotator cuff is associated with posterior glenoid bone loss and posterior humeral subluxation. Management of severe glenoid bone loss during shoulder arthroplasty is controversial and technically challenging and options range from humeral hemiarthroplasty, anatomic shoulder replacement with glenoid bone grafting or augmented glenoid component implantation, to reverse replacement with reaming to correct version or structural bone grafting or metallic augmentation of the bone deficiency. Shoulder replacement with severe glenoid bone loss is technically challenging and characterised by higher rates of complications and revisions. Hemiarthroplasty has limited benefit for pain relief and function especially if eccentric glenoid wear exists. Bone loss with >15 degrees of retroversion likely requires version correction include bone-grafting, augmented glenoid components, or reverse total shoulder replacement. Asymmetric reaming may improve version but is limited to 15 degrees of version correction in order to preserve subchondral bone and glenoid bone vault depth. Bone-grafting of glenoid wear and defects has had mixed results with graft-related complications, periprosthetic radiolucent lines, and glenoid component failure of fixation. Implantation of an augmented wedge or step polyethylene glenoid component improves joint version while preserving subchondral bone, but is technically demanding and with minimal short term clinical follow-up. A Mayo study demonstrated roughly 50% of patients with posteriorly augmented polyethylene had radiolucent lines and 1/3 had posterior subluxation. Another wedge polyethylene design had 66% with bone ingrowth around polyethylene fins at 3 years. Long term outcomes are unknown for these new wedge augmented glenoid components. Reverse shoulder arthroplasty avoids many risks of anatomic replacement glenoid component fixation and stability but is associated with a high complication rate (15%) including neurologic and baseplate loosening and often requires structural bone grafting behind the baseplate with suboptimal outcomes or metallic augmented baseplates with limited evidence and short term outcomes. Reverse replacement with baseplate bone grafting or metal augmentation is technically challenging due to limited native glenoid bone stock available for baseplate component ingrowth and long term fixation. Failure to correct glenoid superior inclination and restore neutral version within 10 degrees increases the risks of reverse baseplate failure of fixation, pull out, and failure of reverse replacement. Reverse baseplate failure rates in patients with severe glenoid bone loss and concomitant glenoid bone grafting range from 5–11%. The minimum native glenoid bony contact with the baseplate is unknown but likely is approximately 1cm of native bone contacting a central ingrowth post and a minority (∼15–25%) of native glenoid contacting the backside of the baseplate. Failure to correct posterior bone loss can lead to retroversion of the baseplate, reduced external rotation, posterior scapular notching, and posteromedial polyethylene wear. In summary, shoulder replacement with severe glenoid bone loss is technically challenging and characterised by higher rates of complication and revision

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

In older patients (>75 years of age), with an intact rotator cuff, requiring a total shoulder replacement (TSR) there is, at present, uncertainty whether an anatomic TSR (aTSR) or a reverse TSR (rTSR) is best for the patient. This comparison study of same age patients aims to assess clinical and radiological outcomes of older patients (≥75 years) who received either an aTSR or a rTSA. Consecutive patients with a minimum age of 75 years who received an aTSR (n=44) or rTSR (n=51) were prospectively studied. Pre- and postoperative clinical evaluations included the ASES score, Constant score, SPADI score, DASH score, range of motion (ROM) and pain and patient satisfaction for a follow-up of 2 years. Radiological assessment identified glenoid and humeral component osteolysis, including notching with a rTSR. Postoperative improvement for ROM and all clinical assessment scores for both groups was found. There were significantly better patient reported outcome scores (PROMs) in the aTSR group compared with the rTSR patients (p<0.001). Both groups had only minor osteolysis on radiographs. No revisions were required in either group. The main complications were scapular stress fractures for the rTSR patients and acromioclavicular joint pain for both groups. This study of older patients (>75 years) demonstrated that an aTSR for a judiciously selected patient with good rotator cuff muscles can lead to a better clinical outcome and less early complications than a rTSR

In reverse shoulder arthroplasty (RSA), a high complication rate is noted in the international literature (24.7%), and limited local literature is available. The complications in our developing health system, with high HIV, tuberculosis and metabolic syndrome prevalence may be different from that in developed health systems where the literature largely emanates from. The aim of this study is to describe the complications and complication rate following RSA in a South African cohort. An analytical, cross-sectional study was done where all patients’ who received RSA over an 11 year period at a tertiary hospital were evaluated. One-hundred-and-twenty-six primary RSA patients met the inclusion criteria and a detailed retrospective evaluation of their demographics, clinical variables and complication associated with their shoulder arthroplasty were assessed. All fracture, revision and tumour resection arthroplasties were excluded, and a minimum of 6 months follow up was required. A primary RSA complication rate of 19.0% (24/126) was noted, with the most complications occurring after 90 days at 54.2% (13/24). Instability was the predominant delayed complication at 61.5% (8/13) and sepsis being the most common in the early days at 45.5% (5/11). Haematoma formation, hardware failure and axillary nerve injury were also noted at 4.2% each (1/24). Keeping in mind the immense difference in socioeconomical status and patient demographics in a third world country the RSA complication rate in this study correlates with the known international consensus. This also proves that RSA is still a suitable option for rotator cuff arthropathy and glenohumeral osteoarthritis even in an economically constrained environment like South Africa

INTRODUCTION. Shoulder joint prostheses have become the most commonly replaced after knee and hip artificial implants. Reverse shoulder arthroplasty (RSA) is the treatment option for patients with severe osteoarthritis, rotator cuff arthropathy or a massive rotator cuff tear with pseudoparalysis. Though successful, the long-term survival of such implants are limited by wear of the materials in contact [1, 2]. The aim of this study was to investigate RSA wear in vitro using a clinically relevant activities of daily living (ADLs). MATERIALS AND METHODS. Four new JRI Orthopaedics Reverse Shoulder 42 mm diameter VAIOS with cobalt-chromium (CoCr) glenospheres and ultra-high molecular weight polyethylene (UHMWPE) humeral components were tested. A five million cycles wear test was undertaken using the unique Newcastle Shoulder Wear Simulator with dilute bovine serum as a lubricant. “Mug to mouth” was performed as the ADL to the test prostheses in intervals of 100 cycles, following by 5 seconds of high load (450N) with no motion simulating an ADL such as “lifting an object”. This combined load cycle was then repeated. A fifth reverse shoulder prosthesis was subject to dynamic loading only in a soak control station. Wear was assessed gravimetrically and roughness (Sa) of the articulating surfaces was measured with a non-contacting profilometer. RESULTS AND DISCUSSION. The mean wear rate and standard deviation of the UHMWPE components was 11.4±3.7 mm. 3. /million cycles, while the CoCr components showed minimal wear over the test duration of 0.01± 0.02 mm. 3. /million cycles (Fig.1). Wear rates are comparable with Kohut et al. (14.1 mm. 3. /million cycles) [3] and Smith et al. (14.3±1.6 mm. 3. /million cycles) [4]. The CoCr glenospheres roughness was unchanged, from 32±8 nm Sa to 28±8 nm Sa over the 5 million cycles of the test (p=0.017), while the UHMWPE humeral components became smoother, from 692±123 nm Sa to 42±29 nm Sa (Fig.2), showing a statically significant change (p<0.001). CONCLUSION. The present study is the first wear test of artificial shoulder joints using a Motion-Load-Motion configuration as a clinically relevant physiological pattern of motion and load. Results are comparable with those found in the literature for in vitro testing of reverse shoulder replacements. For any figures or tables, please contact the authors directly

Introduction. Reverse shoulder Arthroplasty is a successful treatment for gleno-humeral osteoarthritis. However, components loosening and painful prostheses, related to components wrong positioning, are still a problem for those patients who underwent this kind of surgery. Several new technology has been developed the improve the implant positioning. CT-based intraoperative navigation system is a suitable technology that allow the surgeon to prepare the implant site exactly as planned with preoperative software. Method. Thirty reverse shoulder prostheses were performed at Modena Polyclinic using GPS CT-based intraoperative navigation system (Exactech, Gainsville, Florida). Walch classification was used to assess glenoid type. Planned version and inclination of the glenoid component, planned seating, final version and inclination of the reamer were recorded. Intraoperative and perioperative complication were recorded. Planned positioning was conducted aiming to the maximum seating, avoiding retroversion >10° and superior inclination. Results. Eight patients were male, 22 were female. Mean age was 75 years old (range 58–87). 4 glenoid were type B3, four were B2, 10 cases were B1, 12 case were A1/A2. Posterior or superior augment was used in 15 cases. Mean planned seating was 93%. Mean preoperative version was -7.5±6.9°; Mean planned version was -2±2.8°; Mean intraoperative measured version was -1.9±2.8°; no statistical difference was found between planned and intraoperative version (p=0.16). Mean preoperative inclination was 1.8±6.°; Mean planned inclination was -2.2±2.4°; Mean intraoperative measured inclination was -2.1.9±2.3°; no statistical difference was found between planned and intraoperative version or inclination (respectively p=0.16 and p=0.32). Mean surgical time was 71 minute (range 51–82). Three cases of coracoid ruptures were reported, 1 failure of the system occurred. Discussion. GPS navigation system allows the surgeon to prepare the implant site as planned on Preoperative software in Reverse shoulder arthroplasty, with no statistical difference between planned orientation and intraoperative measured orientation. That means that even in the most difficult cases the surgeon is able to find a good positioning (93% seating)and to replicate it in the operative room. Only one failure of the system occurred, because too much time was passed between CT scan and surgery (9 months). Three coracoid fractures occurred in the first 10 cases: these could be addressed to a lack of confidence with the double lateralization of this prosthesis which increase tensioning on the coracoid and a lack of confidence in tracker positioning, which should be made as proximal as it is possible. Finally, the system needs several improvements to be considered a breakthrough technology, such as humeral component positioning and final control of the implant, but by now is a useful way to improve our surgery, especially in difficult cases

Background. Stemless prostheses are recognized to be an effective solution for anatomic total shoulder arthroplasty (TSA) while providing bone preservation and shortest operating time. Reverse shoulder arthroplasty (RSA) with stemless has not showed the same effectiveness, as clinical and biomechanical performances strongly depend on the design. The main concern is related to stability and bone response due to the changed biomechanical conditions; few studies have analyzed these effects in anatomic designs through Finite Element Analysis (FEA), however there is currently no study analyzing the reverse configuration. Additionally, most of the studies do not consider the effect of changing the neck-shaft angle (NSA) resection of the humerus nor the proper assignment of spatial bone properties to the bone models used in the simulations. The aim of this FEA study is to analyze bone response and primary stability of the SMR Stemless prosthesis in reverse with two different NSA cuts and two different reverse angled liners, in bone models with properties assigned using a quantitative computed tomography (QCT) methodology. Methods. Sixteen fresh-frozen cadaveric humeri were modelled using the QCT-based finite element methodology. The humeri were CT-scanned with a hydroxyapatite phantom to allow spatial bone properties assignment [Fig. 1]. Two implanted SMR stemless reverse configurations were considered for each humerus: a 150°-NSA cut with a 0° liner and a 135°-NSA cut with a 7° sloped liner [Fig. 2]. A 105° abduction loading condition was simulated on both the implanted reverse models and the intact (anatomic) humerus; load components were derived from previous dynamic biomechanical simulations on RSA implants for the implanted stemless models and from the OrthoLoad database for the intact humeri. The postoperative bone volume expected to resorb or remodel [Fig. 3a] in the implanted humeri were compared with their intact models in sixteen metaphyseal regions of interest (four 5-mm thick layers parallel to the resection and four anatomical quadrants) by means of a three-way repeated measures ANOVA followed by post hoc tests with Bonferroni correction. In order to evaluate primary stability, micromotions at the bone-Trabecular Titanium interface [Fig. 3b] were compared between the two configurations using a Wilcoxon matched-pairs signed-rank test. The significance level α was set to 0.05. Results. With the exception of the most proximal layer (0.0 – 5.0 mm), the 150°-NSA configuration showed overall a statistically significant lower bone volume expected to resorb (p = 0.011). In terms of bone remodelling, the 150°-NSA configuration had again a better response, but fewer statistically significant differences were found. Regarding micromotions, there was a median decrease (Mdn = 3.2 μm) for the 135°-NSA configuration (Mdn = 40.3 μm) with respect to the 150°-NSA configuration (Mdn = 43.5 μm) but this difference was non-significant (p = 0.464). Conclusions. For the analyzed SMR Stemless configurations, these results suggest a reduction in the risk of bone resorption when a 0° liner is implanted with the humerus cut at 150°. The used QCT-based methodology will allow further investigation, as this study was limited to one single design and load case. For any figures or tables, please contact the authors directly

Reverse shoulder arthroplasty (RSA) is commonly used to treat patients with rotator cuff tear arthropathy. Loosening of the glenoid component remains one of the principal modes of failure and is the main complication leading to revision. For optimal RSA implant osseointegration to occur, the micromotion between the baseplate and the bone must not exceed a threshold of 150 µm. Excess micromotion contributes to glenoid loosening. This study assessed the effects of various factors on glenoid baseplate micromotion for primary fixation of RSA. A half-fractional factorial experiment design (2k-1) was used to assess four factors: central element type (central peg or screw), central element cortical engagement according to length (13.5 or 23.5 mm), anterior-posterior (A-P) peripheral screw type (nonlocking or locking), and bone surrogate density (10 or 25 pounds per cubic foot [pcf]). This created eight unique conditions, each repeated five times for 40 total runs. Glenoid baseplates were implanted into high- or low-density Sawbones™ rigid polyurethane (PU) foam blocks and cyclically loaded at 60 degrees for 1000 cycles (500 N compressive force range) using a custom designed loading apparatus. Micromotion at the four peripheral screw positions was recorded using linear variable displacement transducers (LVDTs). Maximum micromotion was quantified as the displacement range at the implant-PU interface, averaged over the last 10 cycles of loading. Baseplates with short central elements that lacked cortical bone engagement generated 373% greater maximum micromotion at all peripheral screw positions compared to those with long central elements (p < 0.001). Central peg fixation generated 360% greater maximum micromotion than central screw fixation (p < 0.001). No significant effects were observed when varying A-P peripheral screw type or bone surrogate density. There were significant interactions between central element length and type (p < 0.001). An interaction existed between central element type and level of cortical engagement. A central screw and a long central element that engaged cortical bone reduced RSA baseplate micromotion. These findings serve to inform surgical decision-making regarding baseplate fixation elements to minimize the risk of glenoid loosening and thus, the need for revision surgery

Reverse Shoulder Arthroplasty (RSA) has been widely accepted for the treatment of rotator cuff arthropathy. There are a number of other shoulder pathologies where the reverse shoulder prosthesis can salvage previously untreatable shoulder conditions and restore function to the shoulder. This is a series of cases where RSA has been used to treat shoulder fractures. Material. Our indications for the reverse prosthesis in fracture management were:. Revision of failed fracture fixation with a deficient rotator cuff – 2 patients;. Acute 3 and 4 part fractures in the elderly, osteoporotic – 1 patient;. Acute 4 part fracture dislocation in elderly, osteoporotic – 1 patient;. Revision of non-union and malunions – 5 patients;. Revision of hemiarthroplasties which were initially done for fracture management – 5 patients. Results. There were a total of 14 cases treated for fractures out of 123 reverse shoulder arthroplasties performed. The average age for the fracture cases was 68 years (range 47–87) and for non-fracture RSA cases 73 years (range 51–88). The average follow-up Constant Score was 53 for fracture cases and 67 for non-fracture RSA cases. Complications included 1 dislocation and 1 deep infection. The problem with treatment of complex cases is there is an increased risk of complications. Problems encountered in the use of reverse shoulder arthroplasty in complex diagnoses include: instability, notching of scapula, scapula fractures, sepsis, lack of bone stock, poor quality soft-tissue and deficient deltoid muscle due to numerous previous surgical procedures, distortion of anatomy due to trauma, subscapularis deficiency and problems encountered from metal implants in situ. Conclusion. RSA is a good salvage procedure for cuff deficient shoulder fracture cases

Aim. A significant number of patients undergoing shoulder arthroplasty surgery have C acnes contamination at the end of the primary surgery. The objective of this study is to determine whether patients with C acnes contamination at the end of their primary shoulder surgery have a worse prognosis than those who end up without C. acnes contamination. Method. Prospective study including all patients who underwent a reverse shoulder prosthesis from January 2015 to December 2018. In all of them, 5 to 12 cultures were performed during primary surgery. The patients underwent surgery for shoulder arthritis secondary to rotator cuff tears, acute fracture of the proximal humerus, and sequelae of fracture of the proximal humerus. Exclusion criteria included the existence of previous surgeries on the affected shoulder, the presence of signs of infection, having received infiltrations and / or complementary invasive examinations (Arthro-MRI and Arthro-CT). Follow-up from 2 to 5 years. Functional assessment according to the Constant Functional Scale. All complications were also recorded. Results. 162 patients were included. Of these, 25 had positive cultures for C. acnes at the end of primary shoulder surgery. Average age of 74.8 years. 136 women and 26 men. 75.9% Shoulder arthritis secondary to rotator cuff tears, 13.6% acute fractures and 10.5% sequelae of fractures. There were no differences between patients with C. acnes and those without C. acnes regarding age and indication for surgery. Predominance of men in the group with positive C. acnes (p <0.001). No differences at 2 and 5 years in the Constant functional scale between the two groups (2 years, 59.6 vs 59.2 p 0.870) (5 years, 62.4 vs 59.5 p 0.360). Significant differences regarding the number of complications (p 0.001). Patients without C. acnes had 1 aseptic loosening of the metaglene and patients with C. acnes had 2 infections, 1 dislocation, and 1 revision surgery. Patients with contamination by C. acnes had more comorbidities (p 0.035) than patients without contamination. Conclusions. Patients with C acnes contamination at the end of primary surgery do not have functional differences when compared with patients without contamination at 2 and 5 years, but they have a higher number of complications in the medium term

Abstract. Reverse shoulder arthroplasty (RSA) is being increasingly used for complex, displaced fractures of the proximal humerus. The main goal of the current study was to evaluate the functional and radiographic results after primary RSA of three or four-part fractures of the proximal humerus in elderly patients. Between 2012 and 2020, 70 consecutive patients with a recent three- or four-part fracture of the proximal humerus were treated with an RSA. There were 41 women and 29 men, with a mean age of 76 years. The dominant arm was involved in 42 patients (60%). All surgeries were carried out within 21 days. Displaced three-part fracture sustained in 16 patients, 24 had fracture dislocation and 30 sustained a four-part fracture of the proximal humerus. Patients were followed up for a mean of 26 months. The mean postoperative OSS at the end of the follow-up period was 32.4. The mean DASH score was 44.3. Tuberosity non-union occurred in 18 patients (12.6%), malunion in 7 patients (4.9%), heterotopic ossification in 4 patients (2.8%) and scapular notching in one patient. Anatomical reconstruction was achieved in 25 patients (17.5%), the influence of greater tuberosity healing on shoulder function could not be demonstrated. Heterotopic ossification seems to affect OSS and QDASH, we found statistically significant relation between HO and clinical outcomes. Patients with heterotopic ossification had significantly lower postoperative scores on DASH and OSS (P = .0527). Despite expecting good functional outcome with low complication rate after RSA, the functional outcome was irrespective of healing of the tuberosities

Introduction. Total shoulder replacement is a successful treatment for gleno-humeral osteoarthritis. However, components loosening and painful prostheses, related to components wrong positioning, are still a problem for those patients who underwent this kind of surgery. CT-based intraoperative navigation system is a suitable option to improve accuracy and precision of the implants as previously described in literature for others district. Method. Eleven reverse shoulder prostheses were performed at Modena Polyclinic from October 2018 to April 2019 using GPS CT-based intraoperative navigation system (Exactech, Gainsville, Florida). In the preoperative planning, Walch classification was used to assess glenoid type. The choice of inclination of the glenoid component, the screw length, as well as the inclination of the reamer was study and recorded using specific software using the CT scan of shoulder of each patient (Fig.1, Fig.2). Intraoperative and perioperative complications were recorded. Three patients were male, eight were female. Mean age was 72 years old (range 58=84). Three glenoid were type B2, six cases were B1, two case were type C1. Results. In all cases treated by reverse shoulder prostheses we had obtain good functional results at preliminary follow up. Eight degree posterior augment was used in seven case. Planned version was 0° in eight case, an anti-version of 3° was planned in the other three cases. Final reaming was as preoperatively planned in all cases except one. Mean surgical time was 71 minutes (range 51–82). One case of coracoid rupture has been reported. In all cases the system worked in proper manner without failures, no case of infection was reported. Discussion. It is well known as the more accurate placement of the glenoid led to enhanced long-term survivorship of the implant and decrease complication rates in RSTA. Our first experience with GPS navigation system has been satisfied. Good components’ positioning has been reached in all cases, without deviation from the preoperative planning. Pre-operative preparation using software has been always respected except in one case in which we decided to ream 1mm less to avoid excessive bone loss. In 3 case we decide to increase glenoid anti-version to allow a good cage containment in the scapula. No failure of the system has been recorded, with a little increase in the surgical time respect to traditional surgeries performed in our institute. The first case performed reported coracoid fracture, probably due to lack of experience in coracoid tracker positioning. It is very important to set the surgical theatre and the position of the patient in order to make the coracoid tracker visible for the computer. Screw positioning and length is decisively improved with GPS system compared with traditional implant. The most important advantage is to avoid the malposition of the glenoid component, solving problems like loosening or restriction in shoulder range of motion. We believe that a final cross check between preoperative planning and final control of the prostheses implanted, should be used in the future, but by now the GPS navigation system is a useful way to improve our surgery, especially in difficult cases. For any figures or tables, please contact the authors directly

BACKGROUND. Hybrid total hip arthroplasty (THA) commonly recognized as cementless hemi-spherical acetabular component combined with cemented femoral stem. We have done so called “reverse” hybrid THA with cemented socket and cementless stem and compared with all-cemented THAs. PATIENTS AND METHODS. We have been collecting data on total hip arthroplasty since November, 1993. Reverse hybrid hip replacements were used mainly from February, 2001. We evaluated data on 272 reverse hybrid THAs (223 patients) from this year onward until May, 2010, and compared the results with those from 283 all-cemented THAs (237 patients) between 1993 and May, 2010. Eighty percent or more of patients had diagnosed as secondary osteoarthritis of the hip joint due to dysplasia in our hospitals. Highly cross linked ultrahigh molecular polyethylene (CLP) socket was introduced in October, 1999. We used conventional (not cross linked polyethylene) socket for 82 hips (cemented group-1) operated before October, 1999 and CLP socket for 201 hips (cemented group-2) in all-cemented cases. We used the Kaplan-Meier method for estimation of prosthesis survival and relative risk of revision. The endpoint was radiological loosening or revision. Socket linear wear rates were also assessed in radiographically. Clinical assessment was performed using the Japanese Orthopedic Association (JOA) scores and Merle d'Aubigne & Postel scores. RESULTS. We have 12 hips (11 sockets and 1 stem) with radiological loosening in all cemented series and no hips in reverse hybrid series. A case with stem loosening in all cemented THAs had fractured stem without bony support due to massive osteolysis caused by heavy polyethylene wear. All of the loosening cases had conventional polyethylene socket and six of them were revised. Socket linear wear rates were calculated as 0.171 +/− 0.069, 0.030+/− 0.027, and 0.035+/− 0.026 mm per year for cemented group-1, group-2 and reverse hybrid cases, respectively. Clinical scores were significantly improved those at the time of final follow up compared with those of preoperative assessment. There were significant differences between conventional and cross linked polyethylene cases. We found no significant difference survival to that from cemented THR at 12 years (all cemented: 96.1% (95% CI: 92.7–99.1); reverse hybrid: 100%) (Figure 1). DISCUSSION AND CONCLUSION. With a follow-up of up to 12 years, reverse hybrid THAs performed well, and similarly to all-cemented THRs from the same time period. The reason for loosening was mainly bone loss and osteolysis due to polyethylene socket wear. It is no problem if the stem was installed by cemented or cementless fixation, because the rates of stem loosening were very low in the current study. The reverse hybrid method might therefore be an alternative to all-cemented THR. Longer follow-up time is needed to evaluate whether reverse hybrid hip arthroplasty has any advantages over all-cemented THA