Glenoid Implants Research Articles

An in vitro study of glenoid implant peripheral peg interface mechanics during eccentric loading and lift-off.

Glenoid implants used in anatomic total shoulder arthroplasties typically incorporate peripheral pegs as a design feature to support eccentric loads. These peripheral pegs and the implant-cement-bone interface undergo substantial cyclic tensile-compressive loads during normal activity. Therefore, these pegs are of interest in translating the micromechanics of local implant fixation failure to the biomechanics of gross anatomic failure of the glenoid implant after total shoulder arthroplasty. This study used an in vitro peg-cement-bone construct which incorporated bone tissue acquired from osteoarthritic patients undergoing total shoulder arthroplasty. Strain distributions in the peripheral peg-cement-bone interfaces were analyzed under loading conditions emulating glenoid implant edge displacements. It was found that tensile strains in the interfaces were highest near the backside-peg junction and were greater in magnitude than compressive strains. Notably, strains near the peg's fixation channels were relatively low. These results suggest that cracks may initiate around the peg near the backside and travel downward to cause broader fixation failure.

Advances in Anatomic Total Shoulder Arthroplasty Glenoid Implant Design.

Since the advent of Neer's total shoulder arthroplasty in 1974, glenoid implant design has evolved to optimize patient function and increase implant longevity. Glenoid loosening continues to be a major cause of total shoulder arthroplasty failure due to both patient and implant factors. The more recent development of posterior augmented glenoids, peg fixation with ingrowth potential, inlay implants, zoned conformity implants, and convertible glenoids have all shown promising results in improving glenoid fixation and survival in different clinical circumstances. The increased utilization of 3D CT scans, preoperative planning, and patient-specific instrumentation has paralleled innovation in glenoid implants with the aim of improving the accuracy of glenoid implant placement to further optimize patient function and implant longevity. Specific indications for the variety of glenoid implants available today are still being studied. The shoulder arthroplasty surgeon should consider patient and implant factors and patient goals when determining the appropriate implant for each individual.

The Role of Inlay and Inset Glenoid Implants in Anatomic Total Shoulder Arthroplasty

The Role of Inlay and Inset Glenoid Implants in Anatomic Total Shoulder Arthroplasty

Revising Failed Reverse Total Shoulder Arthroplasty: Comprehensive Techniques for Precise Explantation of Well-Fixed Implants.

With the increased utilization of reverse total shoulder arthroplasty (RTSA), there has been a corresponding increase in the incidence of and demand for revision RTSA3. In cases in which the patient has undergone multiple previous surgeries and presents with well-fixed shoulder implants, even the most experienced shoulder surgeon can be overwhelmed and frustrated. Having a simple and reproducible treatment algorithm to plan and execute a successful revision surgery will ease the anxiety of a revision operation and avoid future additional revisions. The extraction techniques described here strive to preserve the humeral and glenoid anatomy, hopefully facilitating the reimplantation steps to follow. The main principles of implant removal include several consistent, simple steps. In order to revise a well-fixed humeral implant, (1) identify the old implants; (2) create a preoperative plan that systematically evaluates the glenoid and humeral deficiencies; (3) prepare consistent surgical tools, such as an oscillating saw, osteotomes, and/or a tamp; (4) follow the deltoid; (5) dissect the soft tissue with a sponge; (6) dissect the bone with use of an osteotome; and (7) remove the humeral stem in rotation. In cases in which there is also a well-fixed glenoid implant, the surgical procedure will require additional steps, including (8) exposure of the anteroinferior glenoid, (9) disengagement of the glenosphere, and (10) removal of the glenoid baseplate in rotation. Alternatives to revision RTSA include nonoperative treatment, implant retention with conversion of modular components, extensile revision surgical techniques, and/or mechanical implant removal. With the advent of modular humeral and glenoid components, surgeons may choose to change the implant components instead of removing the entire humeral and glenoid implants; however, repeat complications may occur if the previous implant or implant position was not completely revised. When confronted with a tough humeral explantation, an extensile surgical approach involves creating a cortical window or humeral osteotomy to expose the humeral implant. This approach can compromise the humeral shaft integrity, leading to alternative and less ideal reconstruction implant choices, the use of cerclage wires, and/or the use of a strut graft, all of which may complicate postoperative mobilization. If glenoid implant removal is necessary, the glenosphere is removed first, followed by the underlying baseplate component(s). If the glenosphere is stuck or if screws are cold-welded, the use of a conventional mechanical extraction technique with a burr or diamond saw may be required; however, this may lead to additional metal debris and intraoperative sparks. Revision RTSA can lead to high complication rates, ranging from 12% to 70%2, which will often require additional revision surgeries4. The first steps to all revision RTSA procedures include careful surgical exposure and component explantation. A simplified approach to expose the humerus and glenoid, coupled with a systematic and atraumatic approach to remove the implants without inadvertent injuries, will prevent surgical complications and the need for re-revision. The proposed comprehensive technique hopefully will allow precise removal of the humeral and glenoid implants while also preserving the remnant humerus or glenoid for future reconstruction. Few studies have evaluated postoperative patient outcomes in revision RTSA. Chalmers et al. performed a meta-analysis and found that patients were able to achieve a mean elevation of 106°, a mean American Shoulder and Elbow Surgeons score of 63, and a mean Single Assessment Numeric Evaluation score of 522. Boileau showed very similar outcomes, with a mean elevation of 107° and a mean adjusted Constant score of 621. These outcomes are slightly inferior to those of primary RTSA, but patients remain satisfied with their improvement from their preoperative function. Preoperative preparation will reduce intraoperative reparation. Know the existing implant and the unique features of its design, understand the patient anatomy including bone defects, and anticipate all of the potential tools that may be needed.Know your anatomy. The anteromedial deltoid edge will help you identify the scarred-in humeral shaft.Da Vinci said that simplicity is the ultimate sophistication. Some of the most common surgical tools and instruments can be more effective than custom-designed ones.The implant should be removed in rotation.There are some company-specific explantation instruments that can be very helpful. Give the appropriate ones a try, but be prepared to consider alternative solutions. RTSA = reverse total shoulder arthroplastyCT = computed tomographyFE = forward elevation.

Rate of polyethylene wear correlates with earlier glenoid implant failure in anatomic total shoulder arthroplasty with cemented all-polyethylene glenoid components

BackgroundGlenoid component loosening is the most common cause of anatomic total shoulder arthroplasty failure, and osteolysis is a common intraoperative and radiographic finding associated with these failed arthroplasties. While preclinical testing can estimate failure mode and wear rates in the laboratory, there is limited in vivo data measuring polyethylene wear rate and location. MethodsUsing an institutional review board–approved total joint arthroplasty retrieval collection, 56 cemented all-polyethylene glenoid components from eleven different manufacturers were analyzed for in vivo dimensional change. We used the differential thickness measurement between the anteroposterior and superoinferior axes of each radially symmetrical implant to determine the dimensional change along that axis. A physiologic wear vector was determined for each retrieved device. ResultsThe implants had a median dimensional change of 0.13 mm/year (range 0.01-1.01mm/year) and the 25th and 75th percentiles were 0.060 and 0.22 mm/year, respectively. The average time to revision of devices with <0.1mm/year of wear was 140.9 months, while the averages for devices between 0.1-0.2mm/year and ≥0.2mm/year were 80.7 and 54.0 months, respectively. Devices with ≥0.2mm/year of wear had significantly shorter time to revision than those with <0.1mm/year (P = .0006). The devices had a similar material loss distribution in both superior-inferior and anterior-posterior directions, with 29 (52%) devices having a greater material loss in the superior-inferior distribution and the remaining 27 (48%) devices in the anterior-posterior axis. The physiologic wear vector had a mean of 47.3 degrees, with a relatively even distribution across all angles, suggesting that glenoid component loosening can occur along multiple axes. ConclusionWe conclude that polyethylene wear is a contributing factor for early failure of cemented all-polyethylene glenoid implants and that anatomic total shoulder arthroplasty may benefit from advances in polyethylene processing. We also suggest that in vitro testing of new polymers and designs should incorporate motion vectors beyond the traditional IS rocking horse test.

Complications and revisions in metal-backed anatomic total shoulder arthroplasty: a comparative study of revision rates between stemless and stemmed humeral components

BackgroundThe primary objective of this study was to evaluate and compare the incidence of complications and revision surgeries between in two of convertible metal-back glenoid systems in total shoulder arthroplasty (aTSA) groups over a follow-up period of up to five years. MethodsA retrospective analysis included 69 shoulders from 65 patients with primary aTSA. Patients were divided into Group 1 (n=31), receiving convertible cementless stemmed aTSA (Lima SMR) and Group 2 (n=38), receiving humeral head replacement aTSA (Arthrex, Eclipse) both with metal-back glenoid components. Clinical and radiological assessments were conducted at 2, 5, and 10 years postoperatively. Assessments included the following: Constant Score, DASH, SPADI, SSV, Glenohumeral Distance, Critical Shoulder Angle and Lateral Acromion Index. In addition, we compared complications, revision rates and survival rates between groups using Kaplan-Maier curves and Log-Rank-test. ResultsBaseline demographics and preoperative outcome scores showed no significant differences between groups (p≥0.05). The overall revision rate did not significantly differ between groups (Group 1:32% vs. Group 2:24%, p=0.60), nor did the mean time to revision (p=0.27). The mean follow-up was 71±41 months (Group 1: 94±48 months, Group 2: 53±23 months, p<0.001). Kaplan-Meier analysis showed similar mid-term survival probabilities (p=0.94). Revision reasons included rotator cuff insufficiency (n=4 in Group 1, n=2 in Group 2) and glenoid wear/loosening (n=5 in Group 1, n=7 in Group 2). Interestingly, Group 1 demonstrated no occurrence of glenoid metal baseplate or humeral loosening, while complex revisions were more common in the Group 2. At 2 and 5 years, non-revised patients in both groups had similar outcome scores. ConclusionMetal-backed glenoid implants in combination with both stemless and stemmed humeral components in aTSA exhibit comparable revision rates and survival probabilities. Rotator cuff insufficiency and polyethylene wear are the two most common complications leading to revision. To facilitate ongoing monitoring and optimize patient safety, we implemented a modification in the follow-up protocol, transitioning to annual appointments or earlier when necessary. This study underscores the unsolved disadvantages in metal-back components and the importance of a mid- to long-term longitudinal assessment of those patients.

Improved surgical techniques and outcomes with anatomic total shoulder arthroplasty managing B2 glenoids in midterm-follow-up

Abstract Background The aim of this systematic review was to study the outcomes of anatomic total shoulder arthroplasty (aTSA) in B2 glenoids before and after the 2012 publication by Walch et al., which recommended the use of reverse TSA (rTSA) for Walch Type B2 glenohumeral joint arthritis. Methods Using PRISMA guidelines, publications were identified that reported on the outcomes for aTSA used in the management of B2 glenoids. Only studies with at least 2 years of follow-up were considered. Results In the two groups, pre-2012 and post-2012, a total of 779 osteoarthritic B2 shoulders were treated with an aTSA. The average follow-up was 59.32 versus 51.14 months. Over the past 10 years, prosthesis-related complication rates using eccentric reaming have significantly decreased from 13.15% to 3.28% (odds ratio: 3.5; p = 0.0002; confidence interval [CI]: 1.49–8.64). The use of posterior augmented glenoid implants has increased substantially and has maintained a consistently low complication rate of 2.8% (odds ratio: 0.64; p = 0.684, CI: 0.12–3.25), with a mean follow-up of 32.7 months. In the first group (pre-2012), after the implantation of 171 prostheses, 19 complications occurred (11.11%), whereas in the second group (post-2012), 18 complications occurred after 608 operations (2.96%). When combining all surgical options for aTSA in the presence of a B2 glenoid, the results showed that patients after 2012 had significantly lower revision rates compared to patients before 2012 (odds ratio: 3.12; p = 0.0012 CI: 1.56–6.1). Conclusion The outcomes of aTSA since 2012 have improved with lower prothesis-related complication rates when eccentric reaming and posterior augmented glenoid components were used.

Custom Glenoid Implant in Total Shoulder Arthroplasty: Case Report of Two Patients

Glenohumeral arthritis is typically treated with shoulder arthroplasty, however in younger patients with complex glenoid pathology this can become more challenging. Considerations surrounding surgical management strive to provide a functional, stable shoulder, while maintaining options for revision in the future. Custom glenoid implants have emerged as a promising option for patients in this challenging population, however there is a lack of literature surrounding their use for addressing glenoid bone loss for anatomic total shoulder arthroplasty. This case report highlights the course of treatment for 2 patients with severe glenoid bone deficiency and debilitating shoulder pain. A custom glenoid implant was used after careful consideration and review of available options. The use of a convertible custom glenoid implant for these patients allowed for improved function and decreased pain, while preserving options for treatment in the future.

Outcomes of patients undergoing anatomical total shoulder arthroplasty with augmented glenoid components - a systematic review.

Glenoid loosening is an issue in anatomic total shoulder arthroplasty (a-TSA). This has been attributed to abnormal glenoid anatomy, common among these patients. Different alternatives have been proposed to tackle glenoid bone loss and restore joint alignment with augmented glenoid implants being increasingly used to deal with this problem. This systematic review aims to evaluate the clinical and radiological outcomes of patients undergoing augmented glenoid a-TSAs. Our hypothesis was that augmented glenoid components will lead to good patient outcomes with a low incidence of complications and revision procedures. MEDLINE, EMBASE, CENTRAL and CINHAL were searched from inception to February 2022 for information pertaining to outcomes of patients undergoing a-TSA with augmented glenoid implants. Eighteen studies reported on outcomes of 814 a-TSA (800 participants) with a mean follow-up of 3.7 years. Most studies (67%) were Type IV level of evidence. Almost 70% of participants underwent an a-TSA secondary to primary glenohumeral osteoarthritis. Most glenoids were type B2 (73%). Augmented glenoids material was mostly all-polyethylene (81%) with full wedge (45%) and stepped components (38%) designs being the most common. Most studies reported good clinical outcomes. 17 patients (4%) underwent a revision surgery. Our review found that patients undergoing a-TSA with augmented glenoid components report good outcomes at short-to-mid-term follow-up. Further research is warranted to determine if such outcomes remain similar in long term. Level III, Systematic Review of Therapeutic Studies.

Clinical and radiographic outcomes following anatomic total shoulder arthroplasty utilizing an inset glenoid component at 2-year minimum follow-up: a dual center study.

Anatomic total shoulder arthroplasty (aTSA) is a successful and reproducible treatment for patients with painful glenohumeral arthritis. However, long-term outcomes using traditional onlay glenoid components have been tempered by glenoid loosening. Inset components have been proposed to minimize glenoid loosening by reducing edge-loading and opposite-edge lift-off forces with humeral translation. Successful short- and long-term outcomes have been reported while using inset glenoid implants. The current study is the largest study presenting a minimum of 2-year follow-up data following aTSA with an all-polyethylene inset glenoid component (Shoulder Innovations, Holland, MI, USA). A dual center, retrospective review of patients undergoing aTSA using an Inset glenoid component by 2 fellowship-trained shoulder surgeons at 2 separate institutions from August, 2016, to August, 2019, was performed. Minimum follow-up was 2 years. Range of motion (ROM), visual analog scale (VAS) pain scores, Single Assessment Numeric Evaluation (SANE), and American Shoulder and Elbow Surgeons (ASES) scores were obtained. Radiographic outcomes, including central peg lucency and glenoid loosening, were assessed by 3 independent reviewers on the postoperative Grashey and axillary radiographs obtained at the final follow-up. Seventy-five shoulders were included for the final analysis. The mean age of the entire cohort was 64 (±11.4) years. Twenty-one (28%) glenoids were type A1, 10 (13.3%) were type A2, 13 (17.3%) were type B1, 22 (29.3%) were type B2, 6 (8%) were type B3, and 3 (4%) were type D. At a minimum follow-up of 24months (mean: 28.7months), a significant improvement in ROM in all planes was observed. Significant improvements in VAS (5.1-0.9, P<.001), SANE (39.5-91.2, P<.001), and ASES (43.7-86.6, P<.001) scores were observed. There were 4 (5.3%) cases of central peg lucency about the inset glenoid component and one (1.3%) case of glenoid loosening. No revisions were performed for glenoid loosening. At a minimum of 2 years postoperatively, there were significant improvements in ROM, VAS, SANE, and ASES scores with very low rates of central peg lucency and glenoid loosening in patients undergoing aTSA with an inset glenoid component. Further work is needed to determine the long-term benefit of this novel implant.

A comparison of pegged and keeled glenoid clinical outcomes at long-term follow-up after total shoulder arthroplasty

BackgroundThe two main glenoid types used in total shoulder arthroplasty (TSA) are the pegged and keeled glenoid designs. We aimed to determine if a pegged glenoid is superior to a keeled glenoid at long-term follow-up as measured by range of motion (ROM), patient reported outcomes (PROs), and radiographic glenoid loosening. MethodsWe retrospectively reviewed all patients undergoing TSA by a single surgeon at an urban, academic hospital. The cohort was stratified into two groups based on glenoid type – one group consisting of keeled implants and a second group consisting of pegged implants. For each patient, forward elevation (FE), internal rotation (IR), external rotation (ER), visual analog scale (VAS), American Shoulder and Elbow Surgeons (ASES) shoulder score, and simple shoulder test (SST) scores were collected preoperatively and at the most recent follow-up visit. Radiographic variables included acromiohumeral interval (AHI) and glenoid loosening. ResultsAfter applying exclusion criteria, 144 TSAs were included in our study. Of these, 42 (29.2%) had keeled glenoids and 102 (70.8%) had pegged glenoids. Patients with a pegged glenoid implant were older (67.4 vs. 60.7 years; p < 0.001) and had a shorter follow-up time (9.3 vs. 14.4 years; p < 0.001) than patients with a keeled glenoid implant. At the most recent follow-up visit, there were no significant differences among postoperative FE, ER, AHI, or PROs. However, pegged glenoid implants provided significantly more internal rotation (T11 vs. L1; p = 0.010) and were less likely to show evidence of radiographic glenoid loosening (16.7% vs. 42.9%; p=<0.001). Revision rates were not significantly different between the pegged and keeled groups (6.9% vs. 14.3%; p = 0.158). ConclusionAlthough a pegged design correlated with superior internal rotation and less radiographic glenoid loosening, both pegged and keeled glenoid designs offered favorable long-term clinical outcomes following TSA over the long-term.

Metal glenoid augmentation in revision arthroplasty

Glenoid implantation in revision arthroplasty of the shoulder remains atechnical challenge in the case of severe bone loss. Metal glenoid augmentation and patient-specific glenoid implants represent new treatment options with great potential. Virtual planning techniques allow adifferentiated evaluation of the extent of the bone loss and the planning of different augmentation options. Although not clearly defined so far, apatient-specific implant can be indicated if adequate fixation of the base plate in the native bone appears questionable. The planning is carried out with the support of the prostheses manufacturer and the stability is simulated using finite element analysis. Ahigh level of primary stability is achieved by an optimized fitting of the implant into the bony defect. The short-term results are promising. However, in the absence of long-term results and limited options in case of revision, the use of acustom-made glenoid warrants astrict indication.

Clinical and Radiological Outcomes after Total Shoulder Arthroplasty Using Custom-Made Glenoid Components: A Systematic Review.

Reverse total shoulder arthroplasty presents itself sometimes as challenging when it comes to addressing massive bone loss, either in primary or revision settings. Custom components recently have made their way into shoulder prosthetics and are meant to help in the case of extensive glenoid bone destruction. Because of strict indication and the fairly recent introduction of these implants, the usage of custom-made glenoid implants is not very common yet. However, the early results are promising. The purpose of this review was to summarize and analyze the available literature. Therefore, a systematic review was performed according to PRISMA guidelines. A comprehensive search of the databases PubMed, Cochrane, and Livivo was performed to screen for studies reporting on clinical and radiological outcomes of custom glenoid implants. Four studies with a total of 46 shoulders were included in this review. The mean patient age was 68.8 years and the mean time of follow-up was 24.3 months. The weighted means showed an increase in CMS (32.7 points), in ASES (39.8 points), in anteversion (67.4 degrees), and in abduction (51.9 degrees) and a decrease in VAS (5.4 points). Custom-made glenoid implants are therefore a viable option in cases of large combined glenoid bone loss, both in primary and revision shoulder arthroplasty.

Stemless, short and standard humeral stems in total shoulder arthroplasty: is there a difference in intraoperative measures, pain, and outcomes in the short term?

BackgroundAs anatomic total shoulder arthroplasty (aTSA) has evolved, surgeons are utilizing stemless and short-stem humeral implants with increasing frequency. Bone preservation, decreased blood loss, decreased surgical time, decreased pain, and improved outcomes have been described as theoretical advantages for shorter stem and stemless implants. Comparisons of outcomes between different length humeral stems that control for manufacturer and model of humeral and glenoid implants are currently limited. The purpose of this study is to determine if differences exist in the short-term outcomes between stemless, short-stem (SS), and traditional-length (TL) humeral stems in aTSA. MethodsA multicenter international shoulder arthroplasty database utilizing a single implant system was retrospectively analyzed to compare intraoperative and short-term outcomes between stemless, SS, and TL humeral stem implants. Intraoperative measures including surgical time and estimated blood loss were recorded. Postoperative outcomes including improvements in multiple pain measures, Global Shoulder Function Score, Simple Shoulder Test, University of California at Los Angeles, American Shoulder and Elbow Surgeons, and Shoulder Pain and Disability Index scores were compared between the three cohorts at 0-3 months, 3-6 months, 6-12 months, and 1-2 years postoperatively. Statistical analysis was performed using a Student’s unpaired two-tailed t-test to quantify differences in means between cohorts with a P value < .05. Results203 stemless aTSAs were compared with 354 SS and 1159 TL aTSAs. Surgical time showed no difference between stemless (avg 89 min), SS (avg 94 min), and TL (avg 91 min) humeral component use (P > .05). Estimated blood loss was significantly higher in TL (avg 214 cc) when compared to SS (avg 165 cc, P < .001) and stemless (avg 180 cc, P < .001), with no significant difference between SS and stemless (P > .05). No differences were observed in improvement in postoperative pain between any cohort across all pain metrics recorded during the first 3 months postoperatively. Additionally, the stemless aTSA cohort did not show any significantly greater improvement in pain metrics at any time point postoperatively when compared to SS and TL cohorts. When evaluating improvements in global shoulder function, American Shoulder and Elbow Surgeons, Simple Shoulder Test, Constant, University of California at Los Angeles, and Shoulder Pain and Disability Index scores, the stemless cohort did not provide a significant advantage in outcome when compared to the SS and TL cohorts at 6-12 or 12-24 months. Discussion and ConclusionWhile stemless aTSA design provides distinct advantages in select patient populations, the proposed benefit of decreased pain and accelerated postoperative recovery following stemless aTSA are not substantiated by this study. The authors hope this study will aid surgeons in counseling prospective TSA patients in the risks and benefits of stem length selection in total shoulder replacement.

Concordance of Preoperative 3D Templating in Stemless Anatomic Total Shoulder Arthroplasty.

Recent advances in preoperative 3D templating software allow surgeons to plan implant size and position for stemless total shoulder arthroplasty (TSA). Whether these preoperative plans accurately reflect intraoperative decisions is yet unknown, and the purpose of this study was to evaluate concordance between planned and actual implant sizes in a series of patients undergoing stemless TSA. A retrospective cohort of consecutive, anatomic, stemless TSA cases performed by two surgeons between September 2019 and February 2021 was examined. Preoperative templated plans were collected using 3D planning software, and the sizes of planned glenoid, humeral head, and nucleus "stem" implants and other procedural data were recorded, along with sociodemographic information. These predicted parameters were compared with the implant sizes, and the concordance of these templated plans was quantified by direct comparison and bootstrapped simulations. Fifty cases met inclusion criteria, among which perfect concordance across all three implants was observed in 11 cases (22%). The glenoid implant had the highest concordance (80%) relative to the humeral head and nucleus implants (38% and 60%, respectively), which was statistically significant ( P < 0.001). Planned humeral head implants were more often oversized relative to their actual implanted size. However, 84% of the planned humeral heads were within 1 diameter size; in addition, 98% of the planned glenoid implants were within one size and all were within 10 mm of the implanted glenoid backside radius. All nucleus implants were within one size. Final implant sizes demonstrated variable concordance relative to preoperative plans, with glenoid implants having the highest accuracy and humeral heads having the highest variability. Multiple factors contributed to the varying concordances for the different implants, suggesting possible areas of improvement in this technology. These results may have implications for logistics, intraoperative efficiency, and overall cost and underscore the potential value of this technology. Level III.

Identifying areas of screw fixation in glenoids with severe bone loss in shoulder arthroplasty.

Severe glenoid bone loss (SGBL) poses significant technical challenges. Adequate fixation of glenoid implants may require the use of alternative screw placement. Although bone volumes for the spine and lateral pillars have previously been defined, insufficient evidence exists regarding the distribution of screw placement for fixation in such regions for cases with SGBL. The purpose of this study is to evaluate the variability of screw placement. We hypothesize that determining this variability and establishing common patterns of glenoid bone loss will allow for recommendations for preoperative planning, and implant design and selection. An internal registry of 2 high-volume shoulder and elbow surgeons was queried, and 65 three-dimensional scapulae models exhibiting SGBL were identified. A fellowship-trained shoulder and elbow surgeon simulated the placement of two 3.5 mm × 30 mm screws, one in the scapular spine (CS) bone volume and one in the inferior column (IS) bone volume. Three orthogonal reference planes were created using anatomic reference points: the scapula trigonum, estimated glenoid center, and inferior pole. Screw positions were mapped, and deviations from the reference planes were calculated. Mutual positions of the IS to CS were also computed. Intraobserver reliability was assessed using 10 randomly selected samples. Median and 25th and 75th percentiles were reported for screw orientation distributions. Means and standard deviations were reported for screw head positions. We demonstrated excellent intraobserver reliability (intraclass correlation coefficients, 0.90-0.98). Fifty percent of CS were oriented 10°±5° of retroversion from the scapula plane, with 5° ± 5° of inclination. For IS, 50% were positioned 0° ± 4° from the scapula plane, with -33° ± 7° of inclination. The relationship of the IS with the CS was medial and posterior in 49% of cases, lateral and posterior in 45%, and lateral and anterior in 6% of cases. On average, the distance between the CS and IS heads was 25 mm ± 4 mm. For SGBL, adequate fixation of glenoid implants can be achieved by placing screws in the spine and lateral columns, with excellent reproducibility. Future implant designs should accommodate CS positioned -16° to -5° from the scapula plane, with 0° to 12° of inclination, and IS positioned -6° to 4° from the scapula plane, with -40° to -25° of inclination. Moreover, mutual screw positions suggested bone loss distributions anteriorly and inferiorly. Future implant designs should consider the potential benefits of augmentation to accommodate interscrew distances of 21-29 mm and anatomic locations of the IS relative to the CS.

Evaluation of clinical and radiographic outcomes after total shoulder arthroplasty with inset Trabecular Metal-backed glenoid.

Trabecular Metal (TM)-backed glenoid implants were introduced for their theoretical ability to increase osseointegration while minimizing wear and the risk of loosening in total shoulder arthroplasty (TSA). Initial follow-up studies of TM-backed glenoids demonstrated high rates of metallic debris formation around the implant site, raising concerns about longevity. More recent data suggest that metallic debris formation may be less prevalent than previously reported and that the implants may have positive long-term outcomes regardless of debris. The goal of our study was to assess the clinical and radiographic outcomes at mid-term follow-up of TSA using a TM-backed glenoid implant placed with full backside support using an inset technique. We hypothesized that our clinical and radiographic outcomes would be good using this technique. We retrospectively reviewed the charts of 39 patients who underwent 41 TSA procedures with a Zimmer Biomet TM-backed glenoid component performed by a single surgeon between January 2010 and March 2016. After exclusions for death unrelated to surgery and loss to follow-up, 35 patients (37 shoulders) with minimum 2-year clinical follow-up were included in the study. The glenoids were all placed in an inset fashion with full backside support. Clinical, patient-reported, and radiographic outcomes were analyzed. The average follow-up period was 7.2 years (range, 2-11 years). At final follow-up, average shoulder elevation was 153° ± 22° and average external rotation was 53° ± 12°. The average American Shoulder and Elbow Surgeons score was 86.8 ± 19.0, and the average visual analog scale score was 1.3 ± 2.4. Metallic debris was found in 9 shoulders (27%), and radiolucency was observed around the glenoid components in 13 shoulders (39%) on the final postoperative radiographs. Metallic debris and radiolucency findings were low in severity, with average grades of 0.32 (standard deviation, 0.54) and 0.39 (standard deviation, 0.50), respectively. There were no reoperations. This study of 37 shoulders undergoing TSA with a TM-backed glenoid demonstrated 100% implant survivorship at an average follow-up of 7 years. Clinical outcomes were excellent despite the occurrence of some metallic debris formation. The findings suggest that a TM-backed glenoid component implanted in an inset fashion to achieve full backside support can provide good clinical and patient-reported outcomes in TSA patients at mid-term follow-up and suggest that continued consideration of the role of TM-backed glenoids and the optimal technique for implantation may be warranted.

Functional and Radiological Outcomes after Treatment with Custom-Made Glenoid Components in Revision Reverse Shoulder Arthroplasty.

Glenoid implant position and fixation are challenging in severe glenoid defects in reverse total shoulder arthroplasty (rTSA). Custom-made glenoid implants are metal augmented implants that are specially produced for a certain defect. They provide the restoration of the joint line and proper fixation. This retrospective data analysis investigated the clinical and radiological outcomes after revision using custom-made glenoid implants. Between 2018 and 2020, nine patients (10 shoulders) with severe glenoid defects underwent revision rTSA using a custom-made glenoid implant (Materialise Glenius or Lima ProMade). The pre- and postoperative Constant Murley Score (CMS), UCLA Score and Subjective Shoulder Value (SSV) were assessed. Postoperative CT scans and X-rays in two planes were available. The minimum follow-up was 12 months, with a mean follow-up of 23.1 months. The mean preoperative CMS, UCLA Score and SSV were 10.9, 4.1 and 11.0, respectively. The mean postoperative CMS, UCLA Score and SSV showed significant increases of 51.7 (<0.001), 22.9 (<0.001) and 52.0 (<0.001), respectively. There were no signs of loosening implants or scapular notching, and no revision was necessary. This trial showed promising clinical and radiological short-term outcomes for custom-made glenoid components in revision rTSA.

Implantation accuracy of custom-made glenoid implants for treating severe glenoid bone deficiencies with reverse shoulder arthroplasty

BackgroundCustom-made three dimensional–printed glenoid implants for reverse shoulder arthroplasty are a modern treatment option for severe glenoid bone deficiencies. The potential advantages of not only achieving primary stability but also being able to realize the preoperative plan in terms of implantation accuracy at the same time have not yet been sufficiently investigated. The purpose of this study was to quantify the implantation precision of custom-made glenoid implants. MethodsTwelve consecutive patients with severe glenoid bone defects were treated between May 2019 and August 2020 using a custom-made glenoid implant (ProMade) (LimaCorporate, San Daniele, Italy) with reverse shoulder arthroplasty at a single hospital. All patients were eligible for inclusion and could be enrolled in this institutional review board–approved study. The immediate postoperative computer tomography–evaluated position of the glenoid implant was compared with the preoperative computer-based plan, on which the manufacturing process was based. As a result of this comparison, deviation measurements in six degrees of freedom (inclination, version, mediolateral offset, anteroposterior offset, superoinferior offset, and roll rotation) emerged. ResultsThe absolute average (mean value ± standard deviation) implantation deviation related to the plan was 1.6° ± 5.4° for version, 1.9° ± 4.1° for inclination, 0.3 mm ± 3.3 mm for mediolateral offset, 0.1 mm ± 1.9 mm for anteroposterior offset, 0.0 mm ± 2.4 mm for superoinferior offset, and 1.0° ± 6.3° for roll rotation. The augment volume averaged 9.0 cm³ ± 2.6 cm³. All custom-made glenoid implants were implanted with a subjectively sufficient primary stability. ConclusionThis study gives an indication that custom-made three dimensional–printed glenoid implants can be implanted with statistically high accuracy. To evaluate the clinical benefit and radiographic stability, a longer follow-up investigation is needed.

The Accuracy of Three-Dimensional CT Scan Software in Predicting Prosthetic Utilization in Total Shoulder Arthroplasty.

Recent innovations in shoulder arthroplasty include three-dimensional (3D) CT software imaging that can be used to predict which prosthetic implants will be used intraoperatively. Correct prediction of the implants may optimize supply chain logistics for the surgeon, hospital, ambulatory surgery center, and the implant company. The purpose of this study was to examine a single surgeon's experience with this software to determine its predictive accuracy in determining which implants would be used intraoperatively. A retrospective review of patients undergoing total shoulder arthroplasty (TSA) performed by a single surgeon was performed. Inclusion criteria were patients undergoing anatomic (aTSA) or reverse (rTSA) TSA examined preoperatively with the 3D CT planning software. A chart review was performed to compare the accuracy of the preoperative plan in predicting the actual prostheses implanted at surgery. Two hundred seventy-eight shoulders from 260 patients were included. One hundred fifty-one shoulders underwent aTSA, and 127 shoulders underwent rTSA. The surgeon was able to predict the type of arthroplasty (anatomic versus reverse) implanted in 269 of 278 (97%) shoulders. Using the 3D CT software, the surgeon was able to predict all the implants implanted in 68 shoulders (24%). For aTSA, 3D CT imaging successfully predicted all implants implanted in 43 shoulders (28%), glenoid implants implanted in 120 of 148 shoulders (81%), and humeral implants implanted in 54 shoulders (36%). For rTSA, 3D CT imaging successfully predicted all implants implanted in 26 shoulders (20%), glenoid implants implanted in 106 shoulders (83%), and humeral implants implanted in 39 shoulders (31%). The 3D CT software combined with surgeon's judgment provided a high accuracy (97%) in determining the type of arthroplasty, a moderately high accuracy in determining the glenoid implants (81% to 83%), a low accuracy in determining humeral implants (31% to 36%), and a low accuracy in determining all prostheses used for each surgery (20% to 28%). LOE IV-Diagnostic Case Series.