Pegged Component Research Articles

Biomechanical comparison of a novel circular glenoid with peripheral ring fixation to a standard anchor pegged glenoid in total shoulder arthroplasty

BackgroundCurrent standard total shoulder pegged glenoid component designs have a high rate of loosening, which accounts for the most common long-term reason for surgical failure. Glenoid design, method of fixation, and implantation version all play a role in component stability. This study aimed to evaluate the biomechanical stability of a novel circular glenoid with peripheral ring fixation and compare to a standard anchor pegged glenoid both directly and to historical biomechanical data. Additionally, we compared the estimated bone removal for the glenoid design types. MethodsBiomechanical testing was performed to assess the circular glenoid with peripheral ring fixation with regards to stability and resistance to “rocking horse” effect, torsional loosening, resistance to torque dissociation, and axial pullout strength. This was compared directly (pullout strength) and to historical (“rocking horse”) biomechanical data obtained for a standard anchor pegged glenoid. A 3D Computer-Aided Design model of five different scapula sizes and shapes was also utilized to estimate volume bone removed when using implant specific prep instrumentation for each glenoid system. ResultsTensile displacement of the worst-case ring fixation component (size medium) after dynamic rocking was 0.060 mm requiring an average peak torque of 6.21N-m to dissociate the glenoid. The ring fixation component demonstrated a mean pullout strength of 1367 N compared with 645 N for the standard anchor pegged glenoid component. The ring fixation component revealed no loosening when placed under torsional stress. The peripheral ring fixation glenoid preparation on average removed 45% less bone than a standard anchor pegged glenoid. ConclusionThe circular glenoid with peripheral ring fixation demonstrated superior maximum pullout strength and more bone preservation with glenoid preparation when compared to the standard pear-shaped, pegged glenoid components. Compared to published standard pegged glenoid component controls, the glenoid with peripheral ring fixation demonstrated diminished “rocking horse” displacement. Despite the circular anchor ring design, there was no evidence of loosening under torsional stress. Initial biomechanical data is overall promising for this novel glenoid design.

Comparing outcomes of central ingrowth peg vs. noningrowth pegged glenoid components during revision to reverse total shoulder arthroplasty

Comparing outcomes of central ingrowth peg vs. noningrowth pegged glenoid components during revision to reverse total shoulder arthroplasty

Mid- to long-term outcomes of a cemented, all-polyethylene pegged glenoid component in anatomic total shoulder arthroplasty.

The primary aim of this study was to evaluate mid- to long-term survival of an all-polyethylene pegged glenoid component used in anatomic total shoulder arthroplasty (TSA). The secondary aim was to review clinical and radiologic outcomes. A retrospective analysis of a prospectively collected local arthroplasty register of consecutive patients undergoing TSA with an all-polyethylene pegged glenoid between January 2009 and December 2018 was undertaken. In total, 108 TSAs using this implant were performed in our unit in 98 patients (18 men and 80 women), with 10 patients undergoing bilateral TSA. The mean age at the time of the operation was 71.3 years (range, 44-87 years). The mean follow-up period was 5.1 years (range, 2-10.6 years). In addition to survival analysis, clinical evaluation included the postoperative Oxford Shoulder Score, Constant score, and visual analog scale (VAS) pain score, as well as range-of-motion assessment. Radiologic outcomes included an assessment of radiolucency based on the Lazarus grade. Kaplan-Meier survival analysis revealed a 6-year survival estimate of 94.1% for all-cause revision. Revision was required in 6 patients: 4 for cuff failure and 2 for instability. At follow-up, the mean Oxford Shoulder Score was 38.2 (standard deviation [SD], 12.3); mean Constant score, 59.3 (SD, 17.0); and mean VAS pain score, 1.8 (SD, 2.5). Mean forward elevation at final follow-up was 111⁰ (SD, 26.6⁰); mean abduction, 102⁰ (SD, 34.0⁰). Clinical outcomes were maintained at long-term follow-up (>8 years), with the exception of the VAS pain score, which increased by 2.1 points (P=.034). Radiologic assessment revealed that 28 patients had radiolucency consistent with Lazarus grade ≥ 3 with clinical outcomes not being affected. Mid- to long-term follow-up indicates a low revision rate and good clinical survivorship for cemented, all-polyethylene glenoid components. No patients, so far, have undergone revision for glenoid loosening, but radiographic follow-up has shown that 36% of these implants have signs of radiolucency. Further follow-up is required to determine longer-term survivorship.

Mid-term outcomes of a stemless ceramic head anatomic total shoulder replacement

BackgroundIn an anatomic shoulder replacement (aTSR) good results have been reported with the use of a stemless humeral prosthesis. In vitro a ceramic articulation with polyethylene has been shown to produce less polyethylene wear particles than with metal. This study aims to evaluate clinical and radiographic results of a stemless aTSR with a ceramic head articulating with a polyethylene glenoid component, with mid-term follow-up.MethodsAll patients (n = 92) in this prospective study had an aTSR utilizing a stemless humeral component with a ceramic head and a cemented double pegged cemented polyethylene glenoid component for glenohumeral osteoarthritis. Pre- and postoperative clinical evaluations at 2 years were performed using the ASES score, Constant score, SPADI score, DASH score, VAS pain score, patient satisfaction and range of motion. There was a 5-year evaluation of SPADI, ASES, pain, and satisfaction, plus radiographic assessment of glenoid component radiolucent lines and humeral osteolysis.ResultsSeventy-four cases (68.1 ± 7.1 years) had a five-year follow-up and demonstrated active elevation improvement from 91.3° preoperatively to 151.1° (p < 0.001). Further improvement was identified with the ASES from 41.6 to 94.3, the SPADI from 62.9 to 4.3, VAS pain from 5.6 to 0.4 (0–10), and satisfaction levels were at 96%. Sixty-two cases had no glenoid radiolucent lines with a maximum Lazarus score of 2 in one patient. Constant scores, available up to 2 years, improved significantly from 30.3 to 77.9 (p < 0.001). There was one case that required revision for glenoid loosening.ConclusionsOverall, the 5-year results of this ceramic head prosthesis demonstrated good radiographic and clinical outcomes.Trial registrationACTRN12613001183774. Registered: 29 October 2013 - Retrospectively registered.Australian New Zealand Clinical Trials Registry (ANZCTR).

Computed tomography revealed the correlation between radiolucency and alignment of all-polyethylene pegged glenoid component more than 10 years after total shoulder arthroplasty in the Japanese population

BackgroundAnatomical total shoulder arthroplasty (TSA) provides successful long-term outcomes but complications can occur after 10 years that require revision. Computed tomography (CT) is a useful tool for assessing radiolucent lines around the glenoid component of TSA; however, the merits of long-term post-TSA follow up with CT are unclear. The purpose of this study was to evaluate the long-term outcomes after TSA of Japanese population and to identify factors related to radiolucency around the glenoid component using CT. MethodsA retrospective review was conducted of TSA patients who had completed at least 10 years of clinical follow up. Radiographs and CT images of the affected shoulder obtained at the last follow up were evaluated for radiolucent lines around the stem and each peg, superior inclination and retroversion of the glenoid component, subluxation index, and critical shoulder angle (CSA). Shoulder ROM, Constant–Murley score and UCLA score were compared between the preoperative and last follow up period. ResultsEighteen shoulders in 16 patients met the inclusion criteria. Mean patient age was 61 years, mean follow up period was 137 months, and mean Yian CT score was 19%. CT score was significantly highest in pegs located inferiorly (p < 0.05). Mean glenoid superior inclination was 12.6°, retroversion was −0.3°, subluxation index was 46%, and CSA was 33.7°. Glenoid superior inclination was significantly lower (p = 0.007) in shoulders with possible loosening than in cases with no loosening (5.0° vs 15.6°). Mean Constant score and UCLA score improved significantly after TSA, from 25.8 to 10.7 points preoperatively to 70.1 and 28.9 points postoperatively, respectively. Mean shoulder flexion, internal rotation, and external rotation also showed improvement postoperatively. ConclusionTSA provides good long-term outcomes. Radiolucency was present most frequently around the inferior pegs of the glenoid component. Glenoid superior inclination may affect the formation of radiolucent lines around glenoid pegs. Level of evidenceLevel IV; Case Series; Treatment study.

Clinical and radiographic outcomes of total shoulder arthroplasty with a partially cemented all-polyethylene pegged bone-ingrowth glenoid component: a systematic review.

Several articles have been published reporting on the clinical performance of a novel pegged, all-polyethylene glenoid component design which features a central peg, circumferentially fluted, interference-fit peg for tissue integration and three small peripheral pegs for cementing. However, no systematic review exists to this date. The US National Library of Medicine (PubMed/MEDLINE), EMBASE, and the Cochrane Database of Systematic Reviews were queried for publications up to May 2020. Overall, 13 articles were included for analysis (560 operated shoulders, range of mean follow-up: 2-6 years). The survival rate was 98.2% (550 out of 560 cases), while the rate of aseptic loosening was 0.2% (1 out of 560 cases). There were 139 cases (out of 399 reported; 34.1%) with peri-glenoid radiolucency, and 35 cases (out of 223 reported; 15.7%) of asymptomatic central peg osteolysis, with 1 of them undergoing revision. There was fair quality of evidence to show that partially cemented all-polyethylene pegged bone-ingrowth glenoid components produce promising results, with a low revision rate in the short- to medium-term follow-up. Nevertheless, this analysis showed high rates of both radiolucency of the glenoid component and osteolysis around the central peg which raise concern for potential failure of this glenoid component in the long-term follow-up. Systematic review, IV.

Minimum 5-year outcomes of pegged versus keeled all-polyethylene glenoids

BackgroundGlenoid loosening remains one of the most common concerns at mid- to long-term follow-up after total shoulder arthroplasty (TSA). Pegged and keeled designs have been compared at short-term follow-up, but few studies have compared outcomes at mid-term follow-up. Our purpose was to compare minimum 5-year outcomes of pegged and keeled cemented, all-polyethylene glenoids in TSA. The hypothesis was that no difference in functional outcomes or loosening would be found between the 2 components.MethodsWe performed a multicenter retrospective study of TSAs with either a pegged or keeled cemented glenoid. At a minimum of 5 years postoperatively, functional outcomes and radiographic loosening were compared.ResultsForty-seven TSAs were available for follow-up, including 20 pegged and 27 keeled components, at a mean of 79 months (range, 60-114 months) postoperatively. Overall, functional outcomes improved in both groups from preoperatively to postoperatively, and no difference was found between the 2 groups. Radiographic glenoid loosening (score ≥ 3) was observed in 9 of 27 keeled glenoids (33.3%) compared with 5 of 20 pegged glenoids (25%) (P = .54). Loosening was associated with lower postoperative forward flexion (P = .026), lower American Shoulder and Elbow Surgeons scores (P = .030), and higher visual analog scale pain scores (P = .007).ConclusionRadiographic glenoid loosening of a cemented, all-polyethylene component was associated with decreased functional outcomes at minimum 5-year follow-up of TSAs. However, this study showed no difference in loosening rates between keeled and pegged components.

Anatomic Total Shoulder Arthroplasty Using a Self-Pressurizing Pegged Bone-Preserving Cemented Glenoid Component: A 2- to 5-Year Follow-up Study

Background: High rates of radiographic loosening have been reported with various glenoid designs. Many available designs sacrifice most of the bone at the central portion of the glenoid vault, creating large areas of deficiency when revision becomes necessary. The purpose of this study was to report the 2- to 5-year outcome of shoulder arthroplasty using a bone-preserving all-polyethylene glenoid components with self-pressurizing pegs. Methods: Between August 2011 and December 2014, 202 consecutive anatomic total shoulder arthroplasties (TSAs) were performed by a single surgeon with implantation of a self-pressurizing cemented pegged glenoid component in 190 patients (12 patients had both shoulders replaced). Patients were followed up prospectively and evaluated for pain, motion, strength, American Shoulder and Elbow Surgeons (ASES) scores, and radiographic changes. The mean follow-up time was 2.7 (2–5) years. Results: TSA improved pain and function reliably. At the most recent follow-up, 94% of the shoulders had no or mild pain. Motion included 154 ± 25° of elevation, 68 ± 18° of external rotation, and median internal rotation to T10 (range, iliac crest to T4). The most recent average ASES score was 82 ± 15 points. Early postoperative radiographs showed no radiolucent lines. No humeral or glenoid component was considered radiographically loose at the most recent follow-up. Complications requiring reoperation included subscapularis insufficiency (4), posterior instability (2), deep infection (1), stiffness (1), and a painful loose body (1). No components were revised for loosening. Conclusions: Anatomic TSA using a cemented bone-preserving all-polyethylene pegged self-pressurizing glenoid component provided satisfactory clinical outcomes and survival at 2 to 5 years.

Radiographic comparison of finned, cementless central pegged glenoid component and conventional cemented pegged glenoid component in total shoulder arthroplasty: a prospective randomized study

Radiographic lucency of the glenoid component remains a problem after cement fixation in primary total shoulder arthroplasty. Glenoid component design likely contributes to rates of glenoid lucency. The purpose of this study was to prospectively compare radiographic lucency between a finned, cementless central pegged glenoid component (CL component) and a conventional cemented pegged glenoid component (P component) on immediate postoperative and minimum 2-year follow-up radiographs. Fifty-four patients undergoing total shoulder arthroplasty were prospectively randomized to receive an all-polyethylene CL component or a conventional all-polyethylene P component. Three raters graded glenoid lucency and bone interdigitation on immediate postoperative and latest follow-up radiographs. Patients who had undergone revision surgery or had died before evaluation were excluded. Minimum 2-year follow-up was required for inclusion of radiographic evaluation. Fifty patients met inclusion criteria; 42 patients (84%; 20 CL and 22 P) were available for follow-up with the original glenoid implant in place. The mean follow-up duration was 35 months (24-64 months). There were no significant differences in glenoid radiolucency between CL (1/20 [5%]) and P (2/22 [9%]) components at last follow-up (P = .999). Five patients (25%) in the CL group had bone interdigitation. No instances of aseptic glenoid loosening occurred. There were no significant differences in the rate of glenoid lucency between the 2 groups at immediate or an average 35-month follow-up. Both techniques appear to be viable options for initial glenoid component fixation, with CL components allowing possible osseointegration, imparting potential long-term stability.

No correlation between radiolucency and biomechanical stability of keeled and pegged glenoid components

BackgroundThe purpose of this study was to examine biomechanical properties and the degree of radiolucency of two cemented basic glenoid designs for total shoulder arthroplasty. Our hypothesis was that a component with increased micro-motion in the laboratory at time zero would also exhibit a greater amount of radiolucency in patients at a minimum of 2 years post total shoulder arthroplasty.MethodsThirty cadaveric shoulders were divided into 2 groups (keel vs. peg). The glenoid components were first loaded with a single axial eccentric force of 196 N in all orientations and then with a transversal load of 49 N to simulate in vivo loads with abduction. Displacement of the glenoid component was determined with four different linear variable-differential transducers. In the second phase, 56 antero-posterior x-rays of 52 patients with either the same keeled (n = 24) or pegged (n = 32) glenoid component with a minimum of 24 months follow-up were evaluated for radiolucency.ResultsBiomechanically the pegged glenoid showed a significant increase in micro-motion during eccentric axial loading as well as during combined loading in the anterior, posterior, and inferior position as compared to the keeled glenoid (p < 0.05). In contrast all results were significant with greater radiolucency for the keeled glenoid component (p = 0.001).ConclusionWhile the pegged component exhibited a greater amount of micro-motion during biomechanical testing, radiolucency was greater in patients with a keeled component. These findings provide support for both components from different perspectives and highlight the need for well-constructed studies to determine whether glenoid design has an effect on clinical outcome, because influences are multifactorial and biomechanical forces may not recreate forces seen in vivo.

Early migration of a partially cemented fluted glenoid component inserted using a cannulated preparation system.

Radiostereometric analysis (RSA) allows an extremely accurate measurement of early micromotion of components following arthroplasty. In this study, RSA was used to measure the migration of 11 partially cemented fluted pegged glenoid components in patients with osteoarthritis who underwent total shoulder arthroplasty using an improved surgical technique (seven men, four women, mean age 68). Patients were evaluated clinically using the American Shoulder and Elbow Surgeons (ASES) and Constant-Murley scores and by CT scans two years post-operatively. There were two patterns of migration, the first showing little, if any, migration and the second showing rotation by > 6° as early as three months post-operatively. At two years, these two groups could be confirmed on CT scans, one with osseointegration around the central peg, and the second with cystic changes. Patients with osteolysis around the central peg were those with early migration and those with osseointegration had minimal early migration. Both groups,however,had similar clinical results. Rapid early migration associated with focal lucency and absence of osseointegration was observed in three of 11 glenoid components, suggesting that lack of initial stability leads to early movement and failure of osseointegration. Cite this article: Bone Joint J 2017;99-B:674-9.

Survival of the pegged glenoid component in shoulder arthroplasty: part II

Loosening of the glenoid component is a primary reason for failure of an anatomic shoulder arthroplasty. Pegged glenoids were designed in an effort to outperform keeled components. This study evaluated the midterm clinical and radiographic survival of a single implant design with implantation of an in-line pegged glenoid component and identified risk factors for radiographic loosening and clinical failure. There were 330 total shoulder arthroplasties that had been implanted with a cemented, all-polyethylene, in-line pegged glenoid component evaluated with an average clinical follow-up of 7.2 years. Of these shoulders, 287 had presurgical, initial postsurgical, and late postsurgical radiographs (mean radiographic follow-up, 7.0 years). At most recent follow-up, 30 glenoid components had been revised for aseptic loosening. This translated to a rate of glenoid component survival free from revision for all 330 shoulders of 99% at 5 years and 83% at 10 years. Of 287 glenoid components, 120 were considered loose on the basis of radiographic evaluation. Four humeral components were considered loose. Component survival (Kaplan-Meier) free from radiographic failure at 5 and 10 years was 92% and 43%. Severe presurgical glenoid erosion (Walch A2, B2, C) and patient age <65 years were risk factors for radiographic failure. Late humeral head subluxation was associated with radiographic failure. Despite the predominant thinking that pegged glenoid components may be superior to keeled designs, midterm radiographic and clinical failure rates were high with this pegged component design, particularly after 5 years. Advanced presurgical glenoid erosion and younger patient age are risk factors for radiographic loosening. Revision rates underestimate radiographic glenoid loosening.

Comparison of Pegged and Keeled Glenoid Components for Total Shoulder Arthroplasty

Background Limited evidence exists regarding the relative rates of glenoid loosening after total shoulder arthroplasty utilizing pegged or keeled cemented all-polyethylene glenoid components. Methods A systematic review of level I, II, and III studies comparing the development of radiolucent lines and glenoid failure after total shoulder arthroplasty with pegged or keeled glenoid components was conducted. Four articles were included in the final analysis with a total of 203 total shoulder arthroplasties comprising 107 pegged and 96 keeled glenoid components. Results Development of radiolucent lines was less likely with pegged glenoid components with a risk difference of −0.32 (95% CI −0.62, −0.03) favoring the pegged design. There was no statistically significant difference in the rate of radiographically at-risk glenoids, clinical glenoid failure, or the composite endpoint. Conclusions Although the development of radiolucent lines was less likely around pegged glenoid components, there was no significant difference in the rate of radiographic or clinical glenoid failure between pegged and keeled components. More high-quality studies are needed to determine the relative rates of glenoid loosening with pegged and keeled glenoid components.

Clinical and Radiographic Results of an All-Polyethylene Pegged Bone-Ingrowth Glenoid Component.

Loosening of the glenoid component continues to be the main cause of medium and long-term failure of shoulder replacements. The purpose of this study was to evaluate the early clinical and radiographic results following use of an all-polyethylene pegged glenoid component designed for hybrid (biological and cement) fixation. Eighty-three shoulders in 77 patients (mean age, 68.6 years) underwent total shoulder arthroplasty with a pegged hybrid-fixation component (bone-ingrowth glenoid and cemented peg). Outcomes were determined with the American Shoulder and Elbow Surgeons (ASES) score and the Oxford shoulder score. A detailed analysis of radiographs and fine-slice computed tomography (CT) images was performed to determine the extent of bone ingrowth between the flanges and the extent of radiolucent lines at the prosthesis-bone interface. The mean duration of follow-up was 46.7 months (range, 24 to 99 months). At the time of final follow-up, the median ASES score was 97 points (range, 43 to 100 points) and the median Oxford score was 48 points (range, 24 to 48 points). The median active forward elevation was 130° (range, 65° to 170°), median external rotation was 45° (range, 5° to 80°), and median internal rotation was to T11 (range, buttock to T4). Seventy-eight shoulders demonstrated a perfect Lazarus score for radiolucency (0, indicating no radiolucency). Sixty-eight shoulders demonstrated complete osseointegration, with bone ingrowth between all of the flanges seen on coronal CT; 5 demonstrated partial osseointegration; and 10 demonstrated osteolysis around the central peg. Most radiolucent lines were in the inferior Yian zones. There were no correlations between the Yian CT scores and either the ASES or Oxford score (rho = 0.13 and 0.07, respectively). Total shoulder arthroplasty with an all-polyethylene pegged glenoid component, utilizing hybrid fixation, demonstrated excellent clinical and radiographic results at the time of early follow-up. Radiolucent lines were seen most commonly around the inferior pegs of the prosthesis, and this may represent an incipient mode of failure. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Total shoulder arthroplasty using an inlay mini-glenoid component for glenoid deficiency: a 2-year follow-up of 9 shoulders in 7 patients

Glenoid bone loss and severe retroversion can pose difficulties when implanting a glenoid component for total shoulder arthroplasty for primary osteoarthritis. Mini-glenoid implants may be useful in the setting of severe glenoid wear in which a standard pegged glenoid component cannot be placed. This study is a retrospective review, performed over a 3-year period, of patients who received a total shoulder arthroplasty using an inset mini-glenoid in the setting of severe glenoid dysplasia and/or medial glenoid bone loss. We identified patients with a minimum of 2 years' follow-up and evaluated preoperative and postoperative range of motion, visual analog scale scores, Single Assessment Numeric Evaluation scores, complications, and patient satisfaction. Seven patients (4 female and 3 male patients; 9 shoulders) with a mean age of 66 years were treated with the described procedure and had a mean follow-up of 34 months. There were 6 primary arthroplasties and 3 revision cases. Four shoulders were classified as Walch type A2 glenoids, 2 were classified as Walch type C, and 3 were unable to be classified. There was a statistically significant increase in range of motion (forward elevation, 48°; external rotation, 14°), decrease in pain scores (8 points to 1 point), and improvement in Single Assessment Numeric Evaluation scores (31.7% to 89.4%). The mean patient satisfaction score was 8.6 points on a 10-point scale. At 2-year follow-up, total shoulder arthroplasty with a mini-glenoid component can offer adequate pain relief and functional results in the setting of glenoid bone loss or severe retroversion.

Lucent lines and glenoid components: What do they portend?

Glenoid component radiolucent lines following total shoulder arthroplasty are not uncommon postoperative radiographic findings and their incidence varies. With time, a certain percentage of radiolucent lines progress and potentially compromise component stability. The incidence of radiographic lucency progresses from 9% to 27% and then 73% at 2, 5, and 15 years, respectively. Radiolucent lines can be caused by posterior glenoid wear, inflammatory arthritis, design factors such as a metal-backed glenoid implant, and improper implantation techniques where the prosthesis is not fully seated or cement is used to fill a defect. Intraoperative techniques to prevent lucent lines include removing minimal bone from the glenoid vault and pressurizing cement into the cancellous bone at time of glenoid component implantation. Furthermore, a pegged glenoid component rather than a keel type is preferred, as this has been associated with a lower incidence of radiolucent lines.

Computed tomography quantification of bone density adjacent to cemented pegged polyethylene glenoid components in shoulder arthroplasty

Cemented polyethylene devices are the prostheses implanted more frequently, but there is no agreement on the optimal glenoid component design. In this study, bone mineral density (BMD) adjacent to cemented all-polyethylene glenoid components was assessed to gain insights into the characteristics of glenoid bone as a potential risk factor implicated in the failure of shoulder arthroplasty. Twenty-two subjects were examined at an average follow-up of 31 months using the Constant-Murley score (CS) and multi-detector computed tomography. BMD was measured in 5 regions of interest (ROIs) at the sites where radiolucent lines are usually detected. BMD differences among the ROIs were tested. The relationship between BMD and a number of variables (CS subscores, age, gender, follow-up duration) was explored. There was a significant increase in CS scores (p<0.05). Significantly different BMD (p=0.0039) was found in the 5 ROIs, especially between ROIs 2 and 5 (p=0.016, Bonferroni's test) and between ROIs 3 and 5 (p=0.005, Bonferroni's test). BMD was lower in ROI 1 than ROI 3 and in ROI 2 than ROI 4, but the difference was not significant. The heterogeneous BMD distribution may be related to: (1) an interindividual variability in glenoid BMD; (2) the fixation technique; or (3) the different bone response to eccentric loading of the prosthetic head on the glenoid component. BMD analysis may contribute to extent our knowledge on glenoid component loosening and encourage further techniques of glenoid fixation.

Glenoid morphology affects the incidence of radiolucent lines around cemented pegged polyethylene glenoid components

Radiolucent lines (RLL) are frequent findings around cemented all-polyethylene glenoid implants. The present study evaluates the frequency, extend and the clinical impact of RLL around a cemented two-pegged glenoid implant with special focus on the influence of preoperative glenoid morphology. Our hypothesis was that glenoid morphology does not affect clinical outcome and RLL in the investigated setting. Between 2003 and 2008, a total of 113 cases of total shoulder arthroplasties (Affinis, Mathys Ltd Bettlach, Switzerland) were performed in three surgical centres using a pegged cemented polyethylene glenoid component. A total of 90 cases could be evaluated clinically and radiographically. Clinical outcome was analysed using the constant score (CS) and range of motion assessment. Radiographic evaluation was performed in true anterior-posterior and axial views with special focus on loosening and RLL. Further, preoperative glenoid morphology was documented and its correlation to radiolucent lines and clinical outcomes was evaluated. At a mean of 58.8 (range 31.2-92.5)-month follow-up the CS improved from 21.5 points preoperatively to 62.3 points postoperatively. Radiolucent lines were found in 76.6% of cases. If present, RLL were located at the backside of the implant (74.4%) in the majority of the cases not around the pegs (10%). There was no significant correlation between RLL and clinical outcome or follow-up time. The amount and extend of RLL were correlated to glenoid morphology with significantly higher values for glenoid types B2 and C according to Walch in comparison to glenoid types A1, A2 and B1. RLL did not affect clinical outcome and did not correlate with the follow-up time. Patients with glenoid morphology types B2 and C showed significantly worse radiographic results. Level IV case series study.

Glenoid Component Retroversion Is Associated with Osteolysis

It has been suggested that glenoid component retroversion and eccentric loading are an important mechanism leading to glenoid component loosening, but little clinical data have been published to support this concept. Sixty-six shoulders underwent total shoulder replacement with an all-polyethylene press-fit pegged glenoid component designed for osseous ingrowth for treatment of osteoarthritis. These shoulders were followed clinically and with radiographs for an average (and standard deviation) of 3.8 ± 1.8 years (range, two to seven years). Preclinical radiographic loosening was defined as osteolysis around the central peg of the glenoid component. Of the sixty-six shoulders, twenty (30%) had osteolysis around the center peg. The length of time after replacement (p = 0.0006), preoperative glenoid retroversion (p = 0.036), and postoperative glenoid component retroversion (p = 0.041) were correlated with osteolysis around the glenoid center peg and an increase in the Lazarus component loosening grade. Postoperative retroversion correlated with preoperative retroversion (Pearson correlation coefficient = 0.44, 95% confidence interval [CI] = 0.19 to 0.64, p = 0.0011). The presence of osteolysis around the center peg was not correlated with a worse clinical outcome defined by shoulder scores or a reoperation due to glenoid loosening. After adjustment for follow-up time, excessive postoperative glenoid retroversion (≥15°) was associated with an increased odds of osteolysis (odds ratio = 5.23, 95% CI = 1.31 to 20.9]), whereas preoperative glenoid retroversion was associated with no change in the odds of osteolysis. Osteolysis around the center peg of a glenoid component is correlated with component retroversion of ≥15°. This finding suggests that there should be additional investigation into the effects of correcting preoperative glenoid retroversion to prevent osteolysis around the center peg.

Rates of Radiolucency and Loosening After Total Shoulder Arthroplasty with Pegged or Keeled Glenoid Components

The objective of this study was to conduct a meta-analysis and cost-effectiveness analysis of the effect of glenoid design on radiolucency, loosening, and revision after total shoulder arthroplasty. We conducted a systematic review of PubMed, MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and CINAHL with use of a search for the terms arthroplasty AND shoulder AND (peg OR keel). Data on study design and on the end points of radiolucency, loosening, and revision were extracted independently and in duplicate. Random-effect models were used to calculate the pooled risk ratio and risk difference. The risk difference was used to estimate the number needed to treat (the number of individuals who would have to receive a pegged component to avoid one loosening or revision). Eight studies with a total of 1460 patients (mean age, sixty-seven years) were included. The mean study quality was 1.75 points (95% confidence interval [CI], 1.26 to 2.24) on the 3-point modified Jadad scale. There was no significant difference in the risk of any radiolucency (risk ratio, 0.42; 95% CI, 0.12 to 1.42) or in the risk of severe radiolucency (risk ratio, 0.65; 95% CI, 0.23 to 1.82) between pegged and keeled components. The pooled risk ratio for revision was 0.27 (95% CI, 0.08 to 0.88) in favor of pegged components (p = 0.028). At a cost-effectiveness threshold of $50,000 per quality-adjusted life year, pegged components can be between $2325 and $40,920 more expensive than keeled components and still be cost-effective. Our study produced evidence that pegged glenoid components were associated with a lower revision risk compared with keeled components. However, the difference was rather small and will therefore be most meaningful to high-volume shoulder arthroplasty centers. Because of the similarity between primary and secondary costs, pegged glenoid designs were more cost-effective than keeled glenoid designs.