Glenoid baseplate positioning for reverse total shoulder replacements (rTSR) is key for stability and longevity. 3D planning and image-derived instrumentation (IDI) are techniques for improving implant placement accuracy. This is a single-blinded randomised controlled trial comparing 3D planning with IDI jigs versus 3D planning with conventional instrumentation. Eligible patients were enrolled and had 3D pre-operative planning. They were randomised to either IDI or conventional instrumentation; then underwent their rTSR. 6 weeks post operatively, a CT scan was performed and blinded assessors measured the accuracy of glenoid baseplate position relative to the pre-operative plan. 47 patients were included: 24 with IDI and 23 with conventional instrumentation. The IDI group were more likely to have a guidewire placement within 2mm of the preoperative plan in the superior/inferior plane when compared to the conventional group (p=0.01). The IDI group had a smaller degree of error when the native glenoid retroversion was >10° (p=0.047) when compared to the conventional group. All other parameters (inclination, anterior/posterior plane, glenoids with retroversion <10°) showed no significant difference between the two groups. Both IDI and conventional methods for rTSA placement are very accurate. However, IDI is more accurate for complex glenoid morphology and placement in the superior-inferior plane. Clinically, these two parameters are important and may prevent long term complications of scapular notching or glenoid baseplate loosening. Image-derived instrumentation (IDI) is significantly more accurate in glenoid component placement in the superior/inferior plane compared to conventional instrumentation when using 3D pre-operative planning. Additionally, in complex glenoid morphologies where the native retroversion is >10°, IDI has improved accuracy in glenoid placement compared to conventional instrumentation. IDI is an accurate method for glenoid guidewire and component placement in rTSA

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 patients with shoulder arthritis, the ability to accurately determine glenoid morphological alterations affects the outcomes of shoulder arthroplasty surgery significantly. This study was conducted to determine whether there is a correlation between scapular and glenoid morphometric components. Existence of such a correlation may help surgeons accurately estimate glenoid bone loss during pre-operative planning. The dimensions and geometric relationships of the scapula, scapula apophysis and glenoid were assessed using CT scan images of 37 South African and 40 Chinese cadavers. Various anatomical landmarks were marked on the 77 scapulae and a custom script was developed to perform the measurements. Intra-cohort correlation and inter-cohort differences were statistically analysed using IBM SPSS v28. The condition for statistical significance was p<0.05. The glenoid width and height were found to be significantly (p<0.05) correlated with superior glenoid to acromion tip distance, scapula height, acromion tip to acromion angle distance, acromion width, scapula width, and coracoid width, in both the cohorts. While anterior glenoid to coracoid tip distance was found to be significantly correlated to glenoid height and width in the South African cohort, it was only significantly correlated to glenoid height in the Chinese cohort. Significant (p<0.05) inter-cohort differences were observed for coracoid height, coracoid width, glenoid width, scapula width, superior glenoid to acromion tip distance, and anterior glenoid to coracoid tip distance. This study found correlations between the scapula apophyseal and glenoid measurements in the population groups studied. These morphometric correlations can be used to estimate the quantity of bone loss in shoulder arthroplasty patients

Abstract. Aim. Excessive glenoid retroversion and posterior wear leads to technical challenges when performing anatomic shoulder replacement. Various techniques have been described to correct glenoid version, including eccentric reaming, bone graft, posterior augmentation and custom prosthesis. Clinical outcomes and survivorship of a Stemless humeral component with cemented pegged polyethylene glenoid with eccentric reaming to partially correct retroversion are presented. Patients and Methods. Between 2010– 2019, 115 Mathys Affinis Stemless Shoulder Replacements were performed. 50 patients with significant posterior wear and retroversion (Walch type B1, B2, B3 and C) were identified. Measurement of Pre-operative glenoid retroversion and Glenoid component version on a post op axillary view was performed by method as described by Matsen FA. Relative correction was correlated with clinical and radiological outcome. Results. 4 were lost to follow up. 46 patients were therefore reviewed. The mean follow up was 4 years (2–8.9 years). Walch B1, Pre op Retroversion: 12 (8–20), post op retroversion :11.8 (−4 to 19), correction= 0.2. Walch B2, Pre op Retroversion :18.4 (10–32), post op retroversion: 13.2 (1 −22), correction= 5.2. Walch B3, Pre op Retroversion: 19.1 (13–32)post op retroversion : 16.1 (9–25), correction= 3.0. Walch C, Pre op Retroversion: 33.3 (28–42) post op retroversion: 16.0 (6–27), correction= 17.3. 3 patients required revision surgery for rotator cuff failure. Conclusion. Partial correction of glenoid retroversion with eccentric reaming and implantation of cemented pegged polyethylene component leads to satisfactory clinical outcomes at midterm follow up. No revisions for aseptic loosening of the glenoid were required

The results of revision TSA do not historically match the results of primary TSA. This is especially true if the diagnosis is a soft tissue related problem that leads to the revision. When a revision TSA is considered in this setting, instability is the major problem to overcome and a reverse TSA is most often needed. In the past this would require that the glenoid and humeral components be removed. Some manufacturers have produced shoulder prosthetic systems that can be converted to a reverse TSA without removing the humeral stem making the revision surgery potentially easier for both the patient and the surgeon. The data bank from two academic shoulder services were utilised to compare outcomes of revision TSA with and without removing the humeral stem at the time of revision surgery. Sixty-seven patients were identified in which 22 did not have the stem removed and 45 required the stem to be revised. The pre-operative and post-operative data for 1 and 2 years were available. Codman's scores, range of motion, estimated blood loss, time in the operating room, complications and cost of the implants were evaluated. The average blood loss was 280 cc vs. 500 cc, 145 minutes vs. 211 minutes, constant scores were 32 pre-op and 75 post-op vs. 32 pre-op and 70 post-op, complications 0 vs. 9 and the cost of the implants were 23% more in the stem removal group. The results of revision TSA do not match the results of primary arthroplasty. The results of not having to remove the humeral stem when doing a revision arthroplasty vs. using a system that has to remove both components has certain advantages. The overall outcome score are similar, however, the complication rate, blood loss, time in the operating room and cost of the implants are significantly less

The modern humeral head resurfacing was developed by Stephen Copeland, M.D. and introduced in 1986 as an alternative to stemmed humeral implants. At the time, first and second generation monoblock and modular stems with non-offset humeral heads posed many challenges to the surgeon to recreate the pre-morbid humeral head anatomy during anatomic TSA. The consequences of non-anatomic humeral head replacement were poor range of motion, increased native glenoid or glenoid component wear and premature rotator cuff failure. Additionally, the early generation humeral stems were very difficult to extract when revision was needed. The original stemless devices were cup resurfacing implants that were designed based on the early hip experience. The Copeland resurfacing device offered the ability to better match native humeral head anatomy and was considered less invasive and easier to revise. Glenoid exposure required more extensive dissection but TSA could be successfully completed. Clinical results for motion, function and outcome scores are similar to stemmed implants. The survivorship of the implants is also on par with other available implants and loosening has not been an issue. Stress shielding is not reported. Multiple manufacturers offered similar products all designed to try to predictably recreate the pre-morbid anatomy and to make insertion easier. Critical review of resurfacing arthroplasty radiographs has raised concern about the challenges of placing the implant with proper sizing and position. Most surgeons have implanted resurfacing implants as hemiarthroplasties. The development of anatomic TSA implants has allowed surgeons to better recreate the normal pre-morbid anatomy of the humerus. Newer stem designs are convertible or easily removable. This counters many of the original design benefits of resurfacing. The primary reason for revision of resurfacing implants is malposition followed by glenoid arthrosis and rotator cuff failure. Revision surgery after resurfacing has had mixed results. Stemless implants were introduced in Europe 13 years ago. Stemless devices share the benefits of resurfacing as minimally invasive and easier to revise. The added benefit of better glenoid access allows the surgeon to implant a glenoid. Most available implants have minimal follow-up. Mid-term follow-up of one design has demonstrated good fixation and loosening is uncommon. No studies are available that critically evaluate the surgeon's ability to recreate normal pre-morbid anatomy, whether revision arthroplasty is bone preserving and if results of revision will improve

Purpose:. The optimal degree of conformity between the glenoid and humeral components in cemented total shoulder arthroplasty (TSA) has not been established. Glenoid component stability is thought to be at risk due to the “rocking-horse” phenomenom, which, can lead to increased micromotion and loosening in response to humeral head edge loading. The goal of this biomechanical study is to investigate the influence of glenohumeral mismatch on bone-implant interface micromotion in a cemented glenoid implant model. Methods:. Twenty-Five cemented glenoid components (Affiniti, Tornier, Inc., Bloomington, MN, USA) were implanted in polyurethane foam biomechanics testing blocks. Five glenoid sizes, 40 mm, 44 mm, 48 mm, 52 mm and 55 mm (n = 5 per glenoid size), were cyclically tested according to ASTM Standard F-2028-08. A 44 mm humeral head (Affiniti, Tornier, Inc., Bloomington, MN, USA) was positioned centrally within the glenoid fixed to a materials testing frame (MTS Mini-Bionix II, Eden Prairie, MN, USA). Phase I testing (n = 3 per glenoid size) involved a subluxation test for determination of the humeral head translation distance which would be used for phase II cyclic testing. During cyclic loading, the humeral head was translated ± distance for 50,000 cycles at a frequency of 2 Hz, simulating approximately 5 years of device use. Glenoid compression, distraction, and superior-inferior glenoid translation were measured throughout testing via two differential variable reluctance transducers. Results:. Humeral head translation distance was identified as 0.55 mm, 1.09 mm, 2.32 mm, 3.82 mm, and 4.73 mm for each glenoid size, respectively (Figure 1). No significant difference was noted in 40 mm glenoids between cycle 1 and 50,000 for all parameters evaluated during testing (p > 0.05) (Figure 2). Conversely, a significant decrease in superior-inferior translation was present for 44 mm between cycle 1 and 50,000 (p = 0.010) (Figure 3). When analyzing all data from the first two smallest glenoid sizes, glenoid compression and translation both showed significantly increased micromotion with 40 mm glenoid sizes compared with the 44 mm glenoid size (p = 0.010 and p = 0.002, respectively). No significant difference was found with respect to glenoid distraction (p = 0.136). Conclusion:. The first phase of mechanical testing established the subluxation displacement of the humeral head against the glenoid for each prosthetic mismatch couple, which was larger for couples with greater glenohumeral mismatch. During cyclic testing, this displacement distance was covered in the same amount of time leading to differences in humeral head velocity and resultant stresses seen at the implant-cement-foam interfaces. A smaller mismatch in glenohumeral radius may lead to greater stress with shorter humeral translation compared to greater mismatch allowing for larger translations with lower resultant stresses. Data from our study will provide further clarification on the importance of glenohumeral mismatch on implant stability. Further studies are warranted to fully evaluate the impact and optimal amount radial mismatch for a clinical setting

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

Intra-operative complications vary from extremely benign such as glenoid vault penetration to life and limb threatening for example brachial artery injury. Most intra-operative complications can be avoided with careful pre-operative planning, anticipation, and execution. However, even the best planning and execution including fluoroscopic guided reaming cannot prevent all complications. The following intra-operative complications will be discussed in detail in regards to both prevention and management: Glenoid vault penetration, Glenoid component malposition - reverse and primary, Glenoid fracture - reverse and primary, Humeral component malposition - reverse and primary, and Humeral fracture - reverse and primary

The incidence of total shoulder arthroplasty continues to increase. The most common reason for failure of a total shoulder arthroplasty is the glenoid component. Two styles of cemented all-polyethylene components are commonly implanted. These two styles are pegged glenoid and keel glenoid components. Data regarding the superiority of the styles has focused on radiolucent lines, complete loosening and need for revision procedures. Several retrospective and randomised controlled trials have been published to examine these endpoints. There is a trend in the literature to demonstrate decreased rates of radiolucent lines with pegged glenoid components, but a recent systematic review of available trials did not demonstrate a significant difference in the rate of radiolucent lines between the two styles. A slightly increased rate of revision was noted for the keel components. Overall pegged and keel glenoids both still represent good options in total shoulder arthroplasty

Introduction:. Failure of the polyethylene glenoid component is the most common complication of Total Shoulder Arthroplasty (TSA) and accounts for a majority of the unsatisfactory results after this procedure. Nowadays, most of the shoulder prostheses consist of metal on polyethylene bearing components. Repetitive contact between the metal ball and the polyethylene socket produces progressive abrasion of the implant if the moving part is made of polyethylene. Its debris may then lead to an active osteolysis and implant loosening. Failure of the glenoid component is often manifested clinically by pain, loss of function, and the presence of a clunking noise and leads to revision surgery. The use of ceramic balls aims at the reduction of this phenomenon. In many studies regarding knee and hip replacement it has been shown that the use of ceramic on polyethylene is more beneficial in terms of polyethylene wear and failure, when compared to metal on polyethylene. This is to our knowledge the first study to address in direct comparison wear in both TSA and RTSA. Materials and methods:. Two different wear tests were conducted in order to address both TSA and RTSA kinematics. Since up to day, there is no test standard for wear testing neither for TSA nor for RTSA a customised joint simulators were used to create worst-case scenarios motions in both cases. In the TSA testing setup, the orientation of the glenoid component and humeral component was chosen according to M. A. Wirth (2009) study but with the humeral component assembled inferiorly. For the RTSA the applied kinematics was based on a study of G. Kohut (2012) and ISO 14242-1 (2012) standard. Three articulating couples for each material were tested for both TSA and RTSA for total of 5 million cycles. Standard midterm gravimetric measurements were conducted at each 1 million cycles. Results:. The tests are currently ongoing and all results will be presented during next ISTA meeting

Background:. Glenoid component loosening remains as an unsolved clinical problem in total shoulder arthroplasty. Current clinical assessment relies on subjective quantification using a two-dimensional plane X-ray image with arbitrarily defined criteria. There is a need to develop a readily usable clinical tool to accurately and reliably quantify the glenoid component motion over time after surgery. A high-resolution clinical CT has the potential to quantify the glenoid motion, but is challenged by metal artifact from the prosthetic humeral components. The objective of this study is to demonstrate the feasibility of using a clinical CT reconstruction to quantify the glenoid implant motion with the aid of tantalum markers. Methods:. Three spherical tantalum markers of 1.0 mm in diameter were inserted into three peripheral pegs of an all polyethylene glenoid component. The glenoid component was implanted in a sawbone scapula. To determine the effect of metal artifact on quantification of glenoid implant motion, two sawbone humerii were used: one without the prosthetic humeral components and the other with the prosthetic humeral head and stem. Three custom-made translucent spacers with the uniform thickness were placed between the glenoid component and the scapula to produce a gradual translation of the glenoid component from 1 mm to 3 mm. Before and after inserting each spacer, the surface of the glenoid component was digitized by a MicroScribe. The surface points were used to fit a sphere and the corresponding center of the sphere was calculated. The actual translation of the glenoid component was measured as the three-dimensional (3D) distance between the center of the sphere before and after insertion of each spacer. Then, the shoulder model was scanned by a clinical CT with and without the spacers for both humerii conditions. Velcro straps were used to secure the humerus to the glenoid component between the trials. All CT scans were reconstructed in VolNinja software to superimpose the scapula positions (Figure 1). The three tantalum markers were visualized and the center coordinates of the markers were used to measure the 3D distance before and after insertion of each spacer. The accuracy was defined by the difference between the averaged 3D distance measured by CT reconstruction and that measured by the MicroScribe. The standard deviation of the 3D distance measured by each tantalum marker was calculated to evaluate the reliability of the tantalum marker visualization. Results:. Without metal artifact, the accuracy and reliability of quantifying glenoid implant motion using a clinical CT were 0.4 mm and 0.2 mm, respectively (Figure 2). With the presence of metal artifact, the accuracy and reliability were 0.5 mm and 0.4 mm, respectively. The largest difference in quantifying the glenoid component motion with and without the metal artifact was only 0.12 mm. Conclusion:. The current study demonstrated the feasibility of using a clinical CT to quantify glenoid implant motion. With the aid of tantalum markers, a clinical CT can be readily used to quantify the glenoid implant motion accurately and reliably even with the presence of metal artifact from the humeral components