Metal-backed Glenoid Component Research Articles

High revision rate of metal-backed glenoid component and impact on the overall revision rate of stemless total shoulder arthroplasty: a cohort study from the Danish Shoulder Arthroplasty Registry.

There is controversy regarding the results of stemmed and stemless total shoulder arthroplasty (TSA) used for osteoarthritis. Therefore, we aimed to compare revision rates of stemmed and stemless TSA and to examine the impact of metal-backed glenoid components. We included all patients reported to the Danish Shoulder Arthroplasty Register from January 1, 2012 to December 31, 2022 with an anatomical TSA used for osteoarthritis. Primary outcome was revision (removal or exchange of components) for any reason. 3,338 arthroplasties were included. The hazard ratio for revision of stemless TSA adjusted for age and sex was 1.83 (95% confidence interval [CI] 1.21-2.78) with stemmed TSA as reference. When excluding all arthroplasties with a metal-backed glenoid component, the adjusted hazard ratio for revision of stemless TSA was 1.37 (CI 0.85-2.20). For the Eclipse stemless TSA system, the adjusted hazard ratio for revision of a metal-backed glenoid component was 8.75 (CI 2.40-31.9) with stemless Eclipse with an all-polyethylene glenoid component as reference. We showed that the risk of revision of stemless TSAs was increased and that it was related to their combination with metal-backed glenoid components.

Comparable low revision rates of stemmed and stemless total anatomic shoulder arthroplasties after exclusion of metal-backed glenoid components: a collaboration between the Australian and Danish national shoulder arthroplasty registries

BackgroundThe stemmed anatomical total shoulder arthroplasty is the gold standard in the treatment of glenohumeral osteoarthritis. However, the use of stemless total shoulder arthroplasties has increased in recent years. The number of revision procedures are relatively low and therefore it has been recommended that national joint replacement registries should collaborate when comparing revision rates. Therefore, we aimed to compare the revision rates of stemmed and stemless TSA used for the diagnosis of glenohumeral osteoarthritis using data from both the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and the Danish Shoulder Arthroplasty Registry (DSR). MethodsWe included all patients who were registered in the AOANJRR and the DSR from January 1 2012 to December 2021 with an anatomical total shoulder arthroplasty used for osteoarthritis. Revision for any reason was used as the primary outcome. We used the Kaplan-Meier method to illustrate the cumulative revision rates and a multivariate cox regression model to calculate the hazard ratios. All analyses were performed separately for data from AOANJRR and DSR, and the results were then reported using a qualitative approach. Results13066 arthroplasties from AOANJRR and 2882 arthroplasties from DSR were included. The hazard ratio for revision of stemmed TSA with stemless TSA as reference, adjusted for age and gender, was 1.67 (95% CI 1.34-2.09, p<0.001) in AOANJRR and 0.57 (95% CI 0.36-0.89, p=0.014) in DSR. When including glenoid type and fixation, surface bearing (only in AOANJRR) and hospital volume in the cox regression model the hazard ratio for revision of stemmed TSA compared to stemless TSA was 1.22 (95% CI 0.85-1.75, p=0.286) in AOANJRR and 1.50 (95% CI 0.91-2.45, p=0.109) in DSR. The adjusted hazard ratio for revision of total shoulder arthroplasties with metal backed glenoid components compared to all-polyethylene glenoid components was 2.54 (95% CI 1.70-3.79, p < 0.001) in AOANJRR and 4.1 (95% CI 1.92-8.58, p<0.001) in DSR. ConclusionBased on data from two national shoulder arthroplasty registries, we found no significant difference in risk of revision between stemmed and stemless total shoulder arthroplasties after adjusting for the type of glenoid component. We advocate that metal-backed glenoid components should be used with caution and not on a routine basis.

Short-term comparative outcomes of LIMA hybrid, metal-backed, and all cemented polyethylene glenoids

BackgroundThis study aims to compare short-term functional outcomes and conversion rates to reverse shoulder arthroplasty between patients who underwent total shoulder arthroplasty (TSA) using a modular metal-backed glenoid component, a hybrid glenoid component, and an all-polyethylene component. MethodsA retrospective review of individuals undergoing TSA between October 2014 and December 2020 was performed. Inclusion criteria included patients undergoing primary TSA for osteoarthritis during this time frame by 1 surgeon. Preoperative and postoperative variables included demographic information, American Shoulder and Elbow Surgeons score (ASES), and range of motion. Revision rates were also documented. Summary statistics were performed, using a 1-way analysis of variance with Tukey post hoc pairwise comparisons when the outcome reached significance. ResultsFifty-two patients were included with age averaging 68 ± 8.1 years, with body mass index of 31 ± 5.8. 54% of patients were female with 12% having diabetes and only 2% were smokers. Follow-up averaged 42 months with patients undergoing metal-backed glenoid having longer follow-up at 56.5 months (P < .001). ASES, forward elevation, and external rotation (ER) for every implant type improved significantly postoperatively (P < .001) besides internal rotation and ER within the poly group (P = .072). No difference was found between the 3 groups for preoperative and postoperative ASES scores, forward elevation, internal rotation, and ER (P > .05). Two patients within the poly group required revision due to rotator cuff tear (P = .225). ConclusionAt 2 years, functional outcomes and patient-reported outcomes are similar in all 3 glenoid groups. There were slightly higher revision rates within the all-polyethylene group. If outcomes are similar among all groups, modular implant systems may be favorable to make conversion to revision TSA easier.

Short-term radiographic and clinical outcomes of patients treated with anatomic total shoulder arthroplasty using a modern-generation implant with a metal-backed glenoid component

BackgroundA leading cause of anatomic total shoulder arthroplasty failure continues to be glenoid component loosening. Historically, metal-backed glenoids (MBG) have shown decreased performance compared to polyethylene-backed glenoid (PEG) components. Previous studies have shown that MBG components have higher revision rates and shorter time to prosthetic failure compared with PEG components. However, the negative outcomes of many of these studies may have been linked to an examination of older generations of MBG implants, and do not account for newer technology. Thus, our study aims to assess the short-term radiographic and clinical outcomes of patients treated with anatomic total shoulder arthroplasty using the current and more modern generation of implants with a universal metal-backed glenoid component. MethodsWe conducted a retrospective chart review of patients who had their primary anatomic shoulder replacement performed from 2017 to 2022 by a single surgeon, and used one of two currently available implants that incorporated a metal-backed glenoid component with a convertible baseplate. After the exclusion of those lost to follow-up, we included 26 patients in this study, 3 of whom underwent bilateral shoulder replacement surgery at staggered time intervals. The primary outcome measure was evidence of radiographic change via in-office X-ray. Analysis of radiographic changes was conducted for each postoperative visit, which was aimed for 2 weeks, 6 weeks, 12 weeks, 1 year, and annually thereafter. Secondary analysis tracked clinical progression and utilized DASH scores, range of motion evaluation, strength testing, and instability examination using evidence of apprehension and sulcus signs at each time interval. ResultsIn our study, radiographic changes at each time interval and the longest follow-up appointment demonstrated no evidence of hardware loosening of either the glenoid or the humeral component and no evidence of periprosthetic fracture or hardware failure of any kind for MBG implants. There were no revisions performed due to polyethylene wear. The overall average range of motion, strength, and DASH scores were improved at each postoperative visit. ConclusionPrevious studies have suggested that TSA implants with MBG components may be inferior to PEG implants. However, the results of many of these studies may not be as representative of the current implant designs available today. While additional studies are necessary to assess the long-term survivability of the implant and its effects on glenoid bone stock, our findings suggest that university MBG components have minimal complications, do not demonstrate loosening, and have acceptable outcomes in short-term follow-up.

Can convertible metal-backed glenoid components replace cemented polyethylene glenoid components in anatomical total shoulder arthroplasty?

BackgroundAnatomical total shoulder arthroplasty (aTSA) has been used to manage degenerative diseases such as primary osteoarthritis. An increase in the use of this procedure has led to several developments in humeral and glenoid components to improve patient outcomes. This study aimed to compare clinical and radiological outcomes of the newly-introduced convertible metal-backed glenoid components with cemented polyethylene glenoid components in aTSA, and to determine whether the new component would be comparable to a conventional one for reducing the burden of future revision or conversion surgeries.MethodsMedical records of fifty patients who underwent aTSA with at least two years of follow-up were retrospectively reviewed. Eighteen patients received convertible metal-backed glenoid components with vitamin E1-coated liner (MB group), while thirty-two patients received conventional cemented polyethylene glenoid components (PE group). Pre- and postoperative clinical and radiological outcomes (acromion-greater tuberosity angle [AGA] and humeral lateral offset [LO]) at final follow-up were assessed. Radiolucent lines (RLLs) and loosening around the humeral and glenoid components were also evaluated.ResultsClinical outcomes improved after surgery in both groups (all p < 0.001). The arc of rotation measured by AGA improved postoperatively in both groups (all p < 0.001), and AGA and LO were not different according to the type of glenoid components (all p > 0.05). Overall complication rates including RLLs of PE and MB groups were 43.8% (14/32) and 16.7% (3/18), respectively (p = 0.031). Although the PE group had more RLLs than did the MB group (p < 0.05), related symptoms and/or glenoid implant loosening were not observed in both groups. Subscapularis failure occurred in two patients in the PE group and in one in the MB group.ConclusionThe convertible metal-backed glenoid implant with vitamin E1-coated liner may be a good alternative for considering the potential for an easier conversion to reverse total shoulder arthroplasty.

Functional outcomes of a Lima modular shoulder replacement

BackgroundThe use of metal backed glenoid (MBG) components over polyethylene (PE) for total shoulder arthroplasty (TSA) remains controversial. While their advantages and disadvantages are documented, few studies exist demonstrating their efficacy in TSA and conversion rates to a reverse total shoulder arthroplasty (RSA). This study aims to evaluate acute postoperative complications, shoulder pain, functional outcomes, and conversion rates to RSA in patients who underwent TSA using a modular MBG component. MethodsA retrospective review of individuals undergoing TSA between October 2014 and March 2019 was performed. Inclusion and exclusion criteria were defined. Baseline surgical characteristics were collected and outcomes were assessed preoperatively and postoperatively using the visual analog scale and American Shoulder and Elbow Surgeons score at preoperative, 1 year, 2 year, and final follow-up. Revision rates were documented. Summary statistics were performed using a two-tailed Student’s t-test. ResultsThe study’s final cohort consisted of 91 patients, with a mean age of 66.5 ± 8.1 years, an average body mass index of 32.8 ± 6.9 kg/m2, and 53.8% being male. Majority of patients underwent a TSA on the right side (64.9%), with an average operative duration of 105 minutes and EBL of 148.8 mL. The mean follow-up time was 38.8 months. Thirteen patients (14.3%) went onto conversion to an RSA. Among these individuals, 30.8% (n = 4) was due to a traumatic rotator cuff tear (RCT), 23.1% (n = 3) due to excessive PE wear, and 46.2% (n = 6) due to nontraumatic RCT. The average time to revision for all patients was 27.7 ± 24.8 months. Mean time to revision was 17.5 ± 9.8 months for trauma patients, 51.0 ± 3.5 for patients with signs of excessive PE wear, and 22.9 ± 31.3 months for nontrauma patients. Mean preoperative visual analog scale scores were 6.8 ± 2.3 and American Shoulder and Elbow Surgeons scores were 28.5 ± 15.6. Both significantly improved at 1-year, 2-year, 3-year postoperative timepoints as well as the final postoperative timepoint (P < .001). ConclusionPatients undergoing TSA using a MBG component reported no acute postoperative complications and improved shoulder function. A small proportion of patients were converted to RSA for signs of a RCT and excessive component wear. This study may suggest that the MBG design demonstrates a failure rate equivalent to cemented PE component systems; thereby, does not expose patients to subsequent higher rates of revision procedures.

Total shoulder replacement stems in osteoarthritis-short, long, or reverse? An analysis of the impact of crosslinked polyethylene.

The 2021 Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) report indicated that total shoulder replacement using both midhead (TMH) length humeral components and reverse arthroplasty (RTSA) had a lower revision rate than stemmed humeral components in anatomic total shoulder arthroplasty (aTSA)-for all prosthesis types and diagnoses. However, there are many factors that affect the outcome of total shoulder replacement, including stem length and polarity, polyethylene type, and glenoid fixation (cemented vs. cementless). The aim of this study was to assess the impact of these variables in the various primary total arthroplasty alternatives for osteoarthritis (OA) in the shoulder. Data from a large national arthroplasty registry were analyzed for the period April 2004 to December 2020. The study population included all primary aTSA, RTSA, and TMH shoulder arthroplasty procedures undertaken for OA using either crosslinked polyethylene (XLPE) or noncrosslinked polyethylene (non-XLPE). Because of the previously documented and reported higher revision rate compared with other anatomic total shoulder replacement options, those using cementless metal-backed glenoid components were excluded. The rate of revision was determined by Kaplan-Meier 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 with aTSA with cemented non-XLPE glenoid component at 8.7% and RTSA at 6.8%. The revision rate for TMH (with XLPE or non-XLPE) 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 of 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 with 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.

Clinical and Radiologic Outcomes after Anatomical Total Shoulder Replacement Using a Modular Metal-Backed Glenoid after a Mean Follow-Up of 5.7 Years.

Background: Glenoid wear is a common complication of anatomical total shoulder arthroplasty (aTSA) with a metal-backed glenoid (MBG), and the clinical and radiological results of historical implants are poor. The aim of this work was to evaluate the clinical and radiological results of 25 participants as well as the longevity after implantation of an anatomic shoulder prosthesis with a recent, modular cementless flat metal-backed glenoid component after a mean follow-up of 5.7 years. Methods: Clinically, the Simple Shoulder Test (SST), UCLA Activity Score (UCLA), and Constant Murley Score (CMS) were evaluated. Radiographically, the radiolucent lines (RLs), humeral head migration (HHM), and lateral glenohumeral offset (LGHO) were assessed. Survival was calculated with Kaplan–Meier curves and life-table analysis. Results: The mean CMS at follow-up was 46.2 points (range: 14–77; SD: 19.5). In terms of the SST score, the average value was 6.5 points (range: 1–10; SD: 3.5). The UCLA activity score showed a mean value of 5.9 points (range: 1–9; SD: 2.1). There were 17 revisions after a mean follow-up of 68.2 months (range: 1.8–119.6; SD: 27.9). HHM occurred in every patient, with a mean measurement of 6.4 mm (range: 0.5–13.4; SD: 3.9; p < 0.0001). The mean LGHO between the initial postoperative and follow-up images was 2.6 mm (range: 0–4.0; SD: 1.5; p < 0.0001). RLs were found in 22 patients (88%) around the glenoid and in 21 patients (84%) around the humeral head prosthesis. Conclusion: The clinical and radiographic outcomes after metal-backed glenoids were poor at 2.2 to 8.4 years of follow-up. We determined devastating survival in the majority of cases (68%), with mostly inlay wear (71%) as the main reason that led to revision surgery. The use of metalback genoids cannot be recommended based on the data of this study.

Radiologic midterm results of cemented and uncemented glenoid components in primary osteoarthritis of the shoulder: a matched pair analysis.

Cemented all-polyethylene glenoid components are considered the gold standard in anatomic shoulder arthroplasty. New designs of cementless metal backed glenoid components showed promising early and midterm results. The aim of this matched-pair analysis was to compare the radiologic results of two cemented glenoid components and a cementless glenoid component in patients with primary osteoarthritis (OA). Sixty shoulders were clinically and radiologically evaluated after a mean follow-up of 59months. Mean patient age was 70.4years at surgery. Based on the design of the glenoid component (keel, peg, MB), 3 groups with, respectively, 20 shoulders were formed according to the matching criteria time of follow-up, patient age and gender. RLL and osteolysis in anteroposterior and axillary X-ray images were quantified and combined in a radiologic score (R-Score). Higher scores expressed worse radiologic outcomes. Further radiological parameters such as lateral glenohumeral offset (LGHO) and subluxation index were measured according to Walch. The functional results were documented using the age and gender normalized Constant-Murley score. Postoperative R-Score was highest in pegged components (peg: 5.7, keel: 2.4, MB: 1.6; p < 0.001) when combining both radiographs and after separate analysis of anteroposterior radiographs. MB glenoids had the lowest R-score in axillary radiographs (peg: 2.2, keel: 1.4, MB: 0.6; MB vs. keel: p = 0.004, MB vs peg: p < 0.001). RLL were more common (p = 0.004) and severe (p = 0.005) in pegged glenoids (RLL incidence: 77.8%, RLL-score: 2.5) than in MB glenoids (RLL incidence: 30%, RLL-score 0.7) and tended (p = 0.084) to have a higher RLL-score than keeled glenoids (RLL incidence: 63.2%, RLL-score:1.4). Both the osteolysis score (keel vs. peg: p < 0.001, MB vs. peg p < 0.001) and the incidence of osteolysis (keel vs. peg: p = 0.008, MB vs peg: p = 0.003) were significant higher in pegged glenoids (peg: osteolysis score: 3.2, osteolysis incidence: 100%; keel: osteolysis score: 1.0, osteolysis incidence: 63.2%, MB: osteolysis score: 0.9, osteolysis incidence: 60%), while the osteolysis score in axillary images was lowest for MB glenoids (peg: 1.2, keel: 0.9, MB: 0.4; peg vs. MB: p = 0.009, keel vs. MB: p = 0.047). Osteolysis in the central axillary zone was least common in MB glenoids (peg: 50%, keel: 47.4%, MB: 15%; peg vs. MB p = 0.035, keel vs. MB p = 0.041). LGHO was highest in MB glenoids (peg: 54.1, keel: 54.5, MB: 57.8; p < 0.001) but did not increase radiographic loosening (r = 0.007; p = 0.958). Preoperative posterior humeral head subluxation seemed to affect incidence of RLL negatively (pre-op posterior decentered 64.3%, pre-op centered 31.9%; p = 0.201) but did not reach statistical significance. Pegged glenoid components had a concerning rate of RLL and osteolysis. MB glenoid components had a better outcome in axillary radiographs concerning RLL and osteolysis. Increased LGHO did not increase radiographic loosening. Retrospective comperative treatment study Level III.

Comparison of mid-term outcomes of total shoulder arthroplasty for B2 and A glenoids treated with trabecular metal glenoid components

BackgroundTreatment of B2 glenoids in total shoulder arthroplasty (TSA) has been associated with worse clinical outcomes and increased rates of glenoid loosening. The purpose of this study was to describe and compare the mid-term outcomes of TSA using a trabecular metal-backed glenoid in patients with B2 and A glenoids. MethodsPatients who underwent anatomic TSA with a trabecular metal-backed glenoid component (second generation trabecular metal glenoid) for primary osteoarthritis and had minimum 5-year follow-up were reviewed. All patients underwent eccentric glenoid reaming to treat biconcavity, if present. Preoperative imaging was reviewed and patients were divided into 2 groups: Type A and Type B2. Mid-term outcome measures including patient-rated outcome scores (Patient Reported Outcome Measurement Information System and American Shoulder and Elbow Surgeons [ASES]) and shoulder range of motion were determined. ASES score was compared between groups. Radiographs were graded for radiolucent lines and posterior humeral head migration and evaluated for glenoid loosening. ResultsTwenty-two patients had Type A glenoids and 22 patients had B2 glenoids. Sixteen patients in the A group and 18 patients in the B2 group had full radiographic and physical exam follow-up. Both groups had similar follow-up (6.7 ± 1.1 years A, 6.6 ± 0.9 years B2, P = .88). Groups were similar in terms of age at surgery, gender distribution, body mass index, severity of medical comorbidities, and hand dominance distribution. The B2 patients had a mean preoperative glenoid retroversion of 17.5° ± 6.7° and posterior subluxation of 8.5% ± 5.3%. No patients in either group had evidence of glenoid loosening at follow-up. No patients required revision surgery. Nine of 16 in the A group had evidence of mild radiolucent lines (8 grade 1, 1 grade 2). Eight of 18 patients in the B2 group had mild radiolucencies (all grade 1). Two of 16 Type A and 6 of 18 B2 patients had evidence of posterior humeral migration, but all cases were graded as mild. Both groups had similar follow-up mean ASES scores (95.5 A, 89.0 B2, P = .25). ConclusionAt minimum 5-year follow-up, patients who underwent TSA with a trabecular metal-backed glenoid component demonstrated excellent clinical and patient-reported outcomes regardless of preoperative glenoid morphology (A or B2). No patients in either group had evidence of glenoid loosening or required revision surgery. These favorable mid-term outcomes of trabecular metal-backed glenoids in B2 deformities need to be followed longitudinally to determine long-term durability. Level of EvidenceLevel III; Retrospective Comparative Study

Modern trabecular metal-backed glenoid components in total shoulder arthroplasty: What is the evidence? A systematic review.

A number of papers have been published reporting on the clinical performance of modern trabecular metal-backed glenoid components in total shoulder arthroplasty. However, no systematic review of the literature has been published to date. The US National Library of Medicine (PubMed/MEDLINE), and the Cochrane Database of Systematic Reviews and EMBASE were queried for publications from January 1980 to October 2019 utilizing keywords pertinent to total shoulder arthroplasty, trabecular metal, and clinical outcomes. Overall, seven articles were included for analysis (322 operated shoulders, mean follow-up range: 2-4 years). The survival rate of modern trabecular metal-backed glenoid components was 96% (309 out of 322 cases) at 43 months mean follow-up, while the rate of aseptic loosening was 0.3% (1 out of 322 cases). There were 35 cases (10.9%) with glenoid component radiolucency (one of them required revision), and 37 cases (11.5%) of metal debris formation, with four of them undergoing revision. There was low quality evidence to show that the use of modern trabecular metal-backed glenoid components in total shoulder arthroplasty may be safe and effective at short-term follow-up. However, this analysis showed alarmingly high rates of both radiolucency of the glenoid component and metal debris formation which raise concern for potential failure of this glenoid component in the long term. Therefore, we feel that modern trabecular metal-backed glenoid components should be still used with caution as part of a structured surveillance or research program until we know if there is a detriment to the prosthesis in the medium to long term.Level: Systematic review, IV.

Do Modern Designs of Metal-Backed Glenoid Components Show Improved Clinical Results in Total Shoulder Arthroplasty? A Systematic Review of the Literature.

Background:Despite the increased popularity of reverse total shoulder arthroplasty, total shoulder arthroplasty is the standard treatment for advanced shoulder arthritis in young adult patients. Conventional metal-backed glenoid (MBG) designs result in more loosening and revision surgery compared with cemented polyethylene glenoid components. However, modern MBG designs have been recently devised to overcome such drawbacks.Purpose:To compare the radiolucency, loosening, and failure rates of modern MBG designs with those of conventional designs.Study Design:Systematic review; Level of evidence, 4.Methods:A search for relevant articles was carried out using the PubMed, Cochrane Library, and Embase databases using MeSH (Medical Subject Headings) terms and natural keywords. A total of 362 articles were screened. We descriptively analyzed numerical data between the groups and statistically analyzed categorical data, such as the presence of loosening, failure, and revision surgery. The main outcome was the rate of revision surgery or failure. Subgroup analysis according to follow-up duration was performed to reduce heterogeneity.Results:A total of 25 articles (2036 shoulders) were included; 15 articles (1579 shoulders) involved a conventional MBG design, and 10 (457 shoulders) involved a modern design. The mean age of the patients was 64.2 and 66.5 years in the conventional and modern design groups, respectively, with a mean follow-up duration of 102.0 and 56.1 months, a mean gain of forward elevation of 35.1° and 61.7°, and a mean gain of external rotation of 24.2° and 39.2°. The rate of radiolucency was 48.0% and 16.7%, the rate of loosening was 11.2% and 4.9%, and the rate of revision was 15.9% and 2.4%, for the conventional and modern design groups, respectively. Subgroup analysis according to follow-up duration showed that the rates of loosening and revision were significantly lower in the modern design group (P < .001).Conclusion:Our findings suggest that modern MBG designs showed significantly lower loosening and failure rates than conventional designs. The overall results of the comparison, including loosening, failure, change in range of motion, and clinical scores, indicate that modern MBG designs are promising. More long-term follow-up studies on modern MBGs should be conducted.

Cemented vs. uncemented glenoid fixation in total shoulder arthroplasty for osteoarthritis: a New Zealand Joint Registry study

Total shoulder arthroplasty (TSA) is commonly performed for shoulder osteoarthritis (OA). Uncemented metal-backed (MB) glenoid components were introduced in an attempt to avoid glenoid loosening. New Zealand and Australian Joint Registry studies have shown significantly higher revision rates when uncemented MB glenoids are used. We used the New Zealand Joint Registry (NZJR) to compare all-cause revision rates and functional scores for TSAand investigated the trends of glenoid fixation used in New Zealand. The NZJR was accessed for all primary TSA undertaken for OA from January 2000 to December 2017. Patient demographics were collated. All-cause revision rates were reported as rate per 100 component-years. Analysis was repeated excluding the uncemented SMR L2 glenoid (LimaCorporate), as it was a potential confounder. Kaplan-Meier survival analysis was performed. Oxford Shoulder Scores at both 6 months and 5 years were analyzed. A total of 2613 TSAs were performed for OA during the study period, representing 85.0% of all TSAs in New Zealand. Overall, 62.1% of the patients were female. In addition, 69.6% of glenoids were cementedand 30.4% uncemented. The most common uncemented MB glenoid was SMR 86.6% (LimaCorporate), and cemented was Global (DePuy) 49.8%. The revision rate for TSA with uncemented glenoids was significantly higher at 2.03 compared with cemented at 0.41 per 100 component-years (P < .001). Hazard ratio 5.0 for revision of uncemented glenoids. No significant difference was found in Oxford Scores at 6 months (39.7 vs. 40.3, P = .13) or 5 years (42.1 vs. 42.8, P = .22). The most commonmode of failure was glenoid loosening in cemented glenoids (44.4%), and component failure in uncemented (34.8%). Revision for rotator cuff, deep infection, and instability were comparable between groups. When excluding SMR L2, uncemented MB glenoid all-cause revision rates remained significantly higher than cemented (1.42 vs. 0.41 per 100 component-years, P < .001). SMR L1 uncemented MB glenoids had a higher revision rate than the non-SMR uncemented glenoids (1.61 vs. 0.18 per 100 component-years, P = .009). Uncemented glenoid use peaked in New Zealand in 2011 at 46.7% of TSAsbut declined to 20.1% in2017. In the NZJR, primary TSAs undertaken for OA have a significantly higher all-cause revision rate when the glenoid component is uncemented. Uncemented glenoids have a 5.0 times higher revision rate. Excluding SMR L2 glenoids from the analysis, the significantly higher revision rate remained for uncemented glenoids. These data reaffirm that uncemented MB glenoids are associated with higher revision rates.

Medium-term rates of radiolucency after primary total shoulder arthroplasty using a cementless metal-backed pegged polyethylene glenoid.

Total shoulder arthroplasty is an established treatment with the commonest cause of failure loosening of the glenoid component. Hydroxyapatite metal-backed glenoid components could offer better survivorship due to improved fixation. The aim of this study was to investigate periprosthetic radiolucency rates associated with an uncemented, metal-backed polyethylene glenoid component with medium-term results. A single centre retrospective study examining radiological outcomes of the Epoca metal-backed glenoid component. Radiographs were analysed for post-operative adequacy of glenoid seating and radiographs at follow-up assessed for periprosthetic lucencies and any revision procedures were recorded. Forty-one patients were followed up with a mean follow-up time of 5.5 years (3-8 years). Primary indication for total shoulder arthroplasty was osteoarthritis (80%). Mean age was 69 years (53-86 years). Ninety-five per cent of glenoid components were completely seated. At follow-up six patients had undergone revision (14.6%). Thirty of the remaining patients (86%) did not demonstrate any radiolucency on follow-up radiographs. Complete glenoid seating post-operatively was associated with lower rate of subsequent radiolucency and revision (P < 0.01). Low rates of radiolucency at medium-term follow-up with an uncemented metal-backed glenoid, however significant rates of revision. Complete seating of the glenoid component was associated with lower rates of radiolucency and revision.

Metal backed glenoid componentを使用した人工肩関節置換術の成績

Metal backed glenoid componentを使用した人工肩関節置換術の成績

Short-term rates of radiolucency after primary total shoulder arthroplasty using a cementless metal-backed pegged polyethylene glenoid.

Total shoulder arthroplasty has shown good clinical efficacy in treating primary and secondary degenerative conditions of the glenohumeral joint. Glenoid loosening, however, remains the commonest cause of failure. The purpose of this study was to investigate the rate of radiographic periprosthetic lucency associated with the use of an uncemented, pegged, metal-backed polyethylene glenoid component. A retrospective, single-centre study using the Epoca (Synthes, Paoli, Pennsylvania) metal-backed glenoid component. Operations were performed by two experienced consultant upper limb surgeons. Radiographs were analysed for immediate post-operative component seating and periprosthetic radiolucent lines at predefined regular post-operative intervals. Intra- and inter-observer reliability was assessed to improve validity of results. Mean age and follow-up was 72 (48-91) years and 2.5 years (2-5), respectively. Main indications for total shoulder arthroplasty were primary osteoarthritis, rheumatoid arthritis, revision for failed hemi-arthroplasty and acute fracture. Ninety-six per cent of components were completely seated post-operatively. Fifty-four (95%) of the 57 shoulders had no periprosthetic radiolucent lines at most recent follow-up. Complete post-operative glenoid seating was significantly associated with the absence of later periprosthetic radiolucency (p < 0.01). This study reports low early radiolucency rates with the pegged, uncemented, metal-backed polyethylene glenoid prosthesis used. Excellent post-operative glenoid seating is associated with a significantly lower rate of radiolucency. Longer follow-up data are required to confirm these early promising results.Level of evidence: Therapeutic, level IV.

Rotator cuff contact pressures at the tendon-implant interface after anatomic total shoulder arthroplasty using a metal-backed glenoid component

Rotator cuff tears following anatomic total shoulder arthroplasty increase with duration of follow-up. This study aimed to evaluate contact pressure between the rotator cuff tendons and prosthesis after anatomic total shoulder arthroplasty and compare these with the tendon-contact pressures in the native shoulder. Eight entire upper extremities were mounted onto a testing apparatus, and simulated muscle loading was applied to each rotator cuff tendon with the shoulder positioned in abduction, internal rotation, and external rotation. Pressure-sensitive film placed between each tendon and bone was used to measure the resultant tendon contact pressures. Experiments were repeated after anatomic total shoulder arthroplasty using standardized implant sizes, and pressure-sensitive film was used to evaluate tendon-prosthesis contact pressure. Both joint angle and shoulder joint replacement surgery had significant effects on the maximum contact pressure measured between the humeral head and all rotator cuff tendons (P < .05) except the teres minor. The supraspinatus demonstrated a significantly larger peak tendon contact pressure after surgery at 45° of abduction relative to that in the native shoulder (mean difference, 0.2 MPa; P = .031), while the subscapularis had a significantly larger maximum contact pressure at 10° of abduction (mean difference, 0.45 MPa; P = .032) and 90° of abduction (mean difference, 0.80 MPa; P = .008) postoperatively. Anatomic total shoulder arthroplasty results in significantly larger tendon contact pressures relative to those in the native shoulder. High tendon contact pressures may ultimately predispose rotator cuff tendons to postoperative wear-induced damage and tearing.

Outcomes of Trabecular Metal–backed glenoid components in anatomic total shoulder arthroplasty

As glenoid failure is one of the primary causes of failure of anatomic total shoulder arthroplasty (TSA), Trabecular Metal-backed glenoid components have become popular. This study reports implant survival and clinical outcomes of patients who received a Trabecular Metal-backed glenoid component during primary anatomic TSA. Patients who underwent TSA with a Trabecular Metal-backed glenoid component by a single surgeon were identified and reviewed for clinical, radiographic, and patient-reported outcome measures with a minimum of 2 years' follow-up. Of 47 patients identified, radiographic and clinical follow-up was available on 36 patients (77%). Average age was 66.36 years (range, 50-85 years), and the average follow-up 41 months (range, 24-66 months). Three patients showed signs of osteolysis, 4 had radiographic evidence of metal debris, and 1 patient had a catastrophic failure after a fall. Of the 47 TSAs, 5 (11%) were revised to a reverse TSA for subscapularis failure and pain. Visual analog scale for pain scores improved by an average of 4.4. At final follow-up, the average Single Assessment Numeric Evaluation score was 72.4; Penn satisfaction score, 7.5; Penn score, 70.35; and American Shoulder and Elbow Surgeons score, 69.23. Outcome scores were similar in the 7 patients with osteolysis or metal debris compared to those without. Trabecular Metal-backed glenoids had a 25% rate of radiographic metal debris and osteolysis at a minimum 2-year follow-up in this series with one catastrophic failure. This implant should be used with caution, and patients followed closely.

The main cause of instability after unconstrained shoulder prosthesis is soft tissue deficiency

Instability is one of the major causes of failures in unconstrained anatomic total shoulder arthroplasty (TSA). This study reviewed the instabilities that may occur in an anatomic shoulder platform system to identify its potential predictors. We hypothesized that soft tissue deficiency was the main cause of instability and that the best treatment option would be conversion to a reverse shoulder arthroplasty (RSA). Between 2003 and 2013, we reviewed 27 patients who experienced postoperative instability, and the overall incidence was 5.07%. There were 8 hemiarthroplasties (HAs), 14 TSAs with metal-backed glenoid components, and 5 TSAs with cemented glenoid components. We reported 10 isolated subscapularis tears, 6 massive rotator cuff tears, 8 component malpositions, 2 component dissociations or loosening, and 1 humeral shortening. These dislocations occurred early, within the first 6 months postoperatively, in 20 patients and later in 7. Specific procedures were performed in 8 patients, 17 were converted successfully to a RSA, and no surgery was done in 2 patients. At the last follow-up (mean, 36.96 months) Constant scores, Subjective Shoulder Value, and Simple Shoulder Test scores improved significantly to 49.9, 56.4%, and 6.9 of 12, respectively (P < .05). None of the 25 patients who were revised were categorized as failures. Patients who underwent conversion had a better outcome than those who had other specific procedures (P = .001). The major cause of instability in our series was soft tissue deficiency. Most of the patients required conversion, and the platform system we used made conversions easier.

Platform systems in shoulder arthroplasty

A platform system for shoulder arthroplasty can include a convertible modular humeral stem and/or a metal-backed glenoid component to facilitate straightforward conversion from either a hemiarthroplasty or anatomic total shoulder arthroplasty to a subsequent anatomic total shoulder arthroplasty, or more frequently, reverse total shoulder arthroplasty without any revision to the stem and/or glenoid baseplate. Recent studies have demonstrated a decreased rate of intraoperative humeral fracture, complications, and blood loss when a platform system is used and the humeral stem is not exchanged during revision arthroplasty. Future studies with larger patient cohorts are necessary to truly evaluate the potential value and limitations of this technology.