Five- to ten-year follow-up with a partially cemented all-polyethylene bone-ingrowth glenoid component

Glenoid Prosthesis Design Considerations in Anatomic Total Shoulder Arthroplasty

Total shoulder arthroplasty is an increasingly popular option for the treatment of glenohumeral arthritis. Historically, the effectiveness of the procedure has largely been determined by the long-term stability of the glenoid component. Glenoid component loosening can lead to clinically concerning complications including pain with movement, loss of function, and accumulation of debris which may require surgery to revise. In response, there has been a push to optimize the design of the glenoid prosthesis. Traditional contemporary glenoid components use pegs for fixation and are made entirely of polyethylene. Variations on the standard implant include keeled, metal-backed, hybrid, augmented, and inlay designs. There is a wealth of biomechanical and clinical studies that report on the effectiveness of these different designs. The purpose of this review is to summarize existing literature regarding glenoid component design and identify key areas for future research. Knowledge of the rationale underlying glenoid design will help surgeons select the best component for their patients and optimize outcomes following TSA.

Short-term clinical and radiographic outcomes of a hybrid all-polyethylene glenoid based on preoperative glenoid morphology

BACKGROUND

The primary purpose of this study was to compare 2-year anatomic total shoulder arthroplasty (TSA) functional and radiographic outcomes between Walch type A and B glenoids treated with an all-polyethylene glenoid designed for hybrid fixation with peripheral cement and central osseous integration. The secondary purpose was to evaluate outcomes based on central peg technique. The hypotheses were that there would be no difference in short-term radiographic or functional outcome scores based on preoperative glenoid morphology or central peg technique.

METHODS

We performed a multicenter retrospective review of patients who underwent TSA with the same hybrid all-polyethylene glenoid and had minimum 2-year follow-up. Patient-reported outcomes and radiographic outcomes were analyzed based on preoperative Walch morphology and central peg technique. Radiographic analysis included preoperative glenoid morphology; preoperative and postoperative glenoid version, glenoid inclination, and posterior humeral head subluxation; and postoperative glenoid radiolucencies according to the Wirth and Lazarus classifications.

RESULTS

A total of 266 patients with a mean age of 64.9 ± 8.2 years were evaluated at a mean of 28 months postoperatively. Postoperatively, there were significant improvements in all functional outcome measures (P < .001), range-of-motion measures (forward elevation, external rotation at 0°, external rotation at 90°, internal rotation by spinal level, and internal rotation at 90°; P < .001), and strength measures (Constant, external rotation, and modified belly press; P < .001). There were no clinically meaningful differences in functional outcomes or statistically significant differences in radiographic appearance between Walch type A and B glenoids. Subgroup analysis revealed that glenoids with a cemented central peg had the worst radiographic outcomes based on Lazarus scoring.

CONCLUSION

Patients undergoing TSA with a hybrid in-line pegged glenoid have excellent clinical outcomes at short-term follow-up regardless of preoperative glenoid morphology. Different central peg techniques do not appear to play a significant role in the risk of glenoid component lucencies at 2 years postoperatively.

The Definition of Periprosthetic Osteolysis in Shoulder Arthroplasty: A Systematic Review of Grading Schemes and Criteria

BACKGROUND

Periprosthetic osteolysis is a known complication after shoulder arthroplasty that may lead to implant loosening and revision surgery. To date, there is no consensus in the shoulder arthroplasty literature regarding the definition of osteolysis or the grading criteria, thus making it difficult to quantify and compare outcomes involving this complication. The purpose of this study was to perform a systematic review of the literature to assess how periprosthetic osteolysis in shoulder arthroplasty is defined and evaluated radiographically.

METHODS

A systematic review of MEDLINE, Scopus, Cochrane, and CINAHL was performed in August 2021 for studies that provided a definition and/or grading criteria for osteolysis in shoulder arthroplasty. Only studies with a minimum of 2 years of radiographic follow-up were included.

RESULTS

Thirty-four articles met the inclusion criteria. After consolidating studies by the same primary author that included the same grading criteria, 29 studies were examined for their definition and grading criteria for osteolysis. Of these, 19 (65.5%) evaluated osteolysis surrounding the glenoid and 18 (62.1%) evaluated osteolysis surrounding the humerus. There was considerable heterogeneity in the systems used to grade periprosthetic osteolysis surrounding the glenoid, whereas humeral periprosthetic osteolysis was often categorized via visualization into binary or categorical groups (e.g., presence versus absence; mild, moderate, or severe; partial versus complete). Four studies (13.8%) provided novel measurements for assessing either glenoid or humeral osteolysis.

CONCLUSIONS

Considerable heterogeneity exists in the assessment and grading of periprosthetic osteolysis in shoulder arthroplasty. The most common grading systems were binary and used qualitative visual interpretation, making them relatively subjective and prone to bias. Quantitative measurements of osteolysis were infrequently utilized. A standardized method of assessing osteolysis would be of value to facilitate communication and research efforts.

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

BACKGROUND

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.

METHODS

The US National Library of Medicine (PubMed/MEDLINE), EMBASE, and the Cochrane Database of Systematic Reviews were queried for publications up to May 2020.

RESULTS

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.

CONCLUSIONS

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.

LEVEL OF EVIDENCE

Systematic review, IV.

Comparison of press-fit versus peripherally cemented hybrid glenoid components in anatomic total shoulder arthroplasty: minimum 5-year follow-up

Background

A common complication of anatomic total shoulder arthroplasty (aTSA) is aseptic glenoid loosening. Monoblock polyethylene glenoid components with backside ingrowth or on-growth utilize hybrid fixation, with cementation of the peripheral pegs and central ingrowth or on-growth of bone have been designed to decrease glenoid loosening. However, there is a paucity of midterm data comparing cementation of the peripheral peg holes versus all press-fit implantation for hybrid glenoid constructs. The purpose of this study is to compare the minimum five-year clinical and radiographic outcomes of a press-fit hybrid glenoid component with a peripherally cemented hybrid glenoid component in aTSA.

Methods

Between years 2013-2015, we reviewed a total of 169 patients who underwent primary aTSA, with follow-up data spanning a minimum of five years, from an international multi-institutional database. There were 61 press-fit and 108 peripherally cemented glenoids. Shoulders were evaluated for outcome measures, which included clinical outcome scores, radiographic outcomes, and complication rates.

Results

Postoperatively, there were no statistically significant differences in patient satisfaction, shoulder function, pain scoring, the Simple Shoulder Test, the Constant score, the American Shoulder and Elbow Surgeons score, the University of California–Los Angeles score, nor the Shoulder Pain and Disability Index, between the two cohorts. There were no significant differences in adverse events (P = .791) or revision rates (P = .592). At the final radiographic follow-up, there were no significant differences between the two groups with regard to the incidence of radiolucent lines on the glenoid (P = .210) or humeral side (P = .282).

Conclusion

At a minimum of 5-year follow-up, aTSA with a press-fit glenoid implant demonstrates no difference in clinical or radiographic outcomes when compared with a glenoid cohort where the peripheral pegs are cemented. In addition, there is no increased rate of aseptic glenoid loosening or need for revision surgery between the two groups with a lower rate of radiolucency detected than prior midterm data studies. Uncemented press-fit glenoid fixation with a cage component appears to be a safe and effective treatment option for patients undergoing primary aTSA at a minimum of 5-year follow-up.

Relationship Between Glenoid Component Shift and Osteolysis After Anatomic Total Shoulder Arthroplasty: Three-Dimensional Computed Tomography Analysis

BACKGROUND

The purpose of this study was to evaluate glenoid component position and radiolucency following anatomic total shoulder arthroplasty (TSA) using sequential 3-dimensional computed tomography (3D CT) analysis.

METHODS

In a series of 152 patients (42 Walch A1, 16 A2, 7 B1, 49 B2, 29 B3, 3 C1, 3 C2, and 3 D glenoids) undergoing anatomic TSA with a polyethylene glenoid component, sequential 3D CT analysis was performed preoperatively (CT1), early postoperatively (CT2), and at a minimum 2-year follow-up (CT3). Glenoid component shift was defined as a change in component version or inclination of ≥3° from CT2 to CT3. Glenoid component central anchor peg osteolysis (CPO) was assessed at CT3. Factors associated with glenoid component shift and CPO were evaluated.

RESULTS

Glenoid component shift occurred from CT2 to CT3 in 78 (51%) of the 152 patients. CPO was seen at CT3 in 19 (13%) of the 152 patients, including 15 (19%) of the 78 with component shift. Walch B2 glenoids with a standard component and glenoids with higher preoperative retroversion were associated with a higher rate of shift, but not of CPO. B3 glenoids with an augmented component and glenoids with greater preoperative joint-line medialization were associated with CPO, but not with shift. More glenoid component joint-line medialization from CT2 to CT3 was associated with higher rates of shift and CPO. A greater absolute change in glenoid component inclination from CT2 to CT3 and a combined absolute glenoid component version and inclination change from CT2 to CT3 were associated with CPO. Neither glenoid component shift nor CPO was associated with worse clinical outcomes.

CONCLUSIONS

Postoperative 3D CT analysis demonstrated that glenoid component shift commonly occurs following anatomic TSA, with increased inclination the most common direction. Most (81%) of the patients with glenoid component shift did not develop CPO. Longer follow-up is needed to determine the relationships of glenoid component shift and CPO with loosening over time.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Glenoid vault perforation in total shoulder arthroplasty: Do we need computer guidance?

The proliferation of computer 3D simulation and computer-generated guides is aimed at minimizing perforation of the glenoid vault by glenoid pegs in shoulder arthroplasty, based on assumptions that perforation leads to worse outcomes by component loosening and potential failure. We evaluated outcomes of glenoid peg perforation testing the assumption that perforation produces worse results. Eighty-three shoulders underwent shoulder arthroplasty with pegged hybrid fixation (bone-ingrowth flanged central glenoid peg and peripheral cemented pegs) without precision signal injector guides or use of 3D planning software. Outcomes were determined by American Shoulder and Elbow Score and Oxford Shoulder Score. Fine slice CT determined the presence of vault perforation and the extent of lucent lines at the prosthesis-bone interface and bony morphology of the vault perforation. Follow-up was 46.7 months (24-99). Seven shoulders (8%) demonstrated perforation of glenoid vault. Bony ingrowth and cortical overgrowth occurred despite perforation, with no clinically significant differences in clinical or radiological outcomes in shoulders with and without glenoid vault perforation. None of these patients underwent revision surgery. Despite not utilizing computer planning and/or guides, 92% of implants did not perforate the glenoid vault. However, glenoid vault perforation in our series produced excellent outcomes with no increased risk of revision as a result of glenoid vault perforation.

Clinical and radiographic outcomes of an all-polyethylene fluted central peg glenoid component, implanted utilizing an off-label, uncemented technique, at a minimum 5-year follow-up

BACKGROUND

Glenoid component loosening remains an important concern in anatomic total shoulder arthroplasty. The aim of this study was to evaluate the clinical and radiographic results of a fully uncemented all-polyethylene fluted central peg bone-ingrowth glenoid component at a minimum 5-year follow-up.

METHODS

Thirty-five shoulders in 31 patients (mean age, 73 years) with a mean follow-up of 100 months were retrospectively evaluated at an early and mid-term time point for Constant score (CS). Computed tomography visualized glenoid component fixation at both time points.

RESULTS

Mean CS improved from 40 preoperatively to 66 postoperatively at latest follow-up (P < .001). A mean CS of 74 at early follow-up remained consistent with a mean CS of 66 at latest follow-up (P = .158), with only strength demonstrating a decrease over time (P < .001). An initial osseointegration rate of 81% at early follow-up decreased to 71% at latest follow-up with 74% of the shoulders demonstrating progressive radiolucent lines, resulting in a radiographic loosening rate of 31%. Of the 35 shoulders, 4 were revised (survival rate of 88%), of which 2 due to symptomatic aseptic loosening.

CONCLUSIONS

Uncemented fixation of an all-polyethylene central peg bone-ingrowth glenoid was associated with satisfactory clinical and radiographic scores, and an acceptable revision rate at mid- to long-term follow-up. Despite initial bony osseointegration in the majority of cases, radiographic loosening over time remains a concern, potentially jeopardizing long-lasting fixation of this type of glenoid component when implanted in an off-label uncemented fashion.

The association between glenoid component design and revision risk in anatomic total shoulder arthroplasty

INTRODUCTION

Anatomic total shoulder arthroplasty (TSA) is a proven treatment for glenohumeral joint osteoarthritis, with superior results compared with hemiarthroplasty. However, glenoid component loosening remains a problem and is one of the most common causes of failure in TSA. Multiple component designs have been developed in an attempt to reduce loosening rates. The purpose of this study was to evaluate risk of revision after anatomic TSA according to the glenoid component design.

METHODS

We conducted a cohort study including patients aged ≥18 years who underwent primary elective TSA for the diagnosis of osteoarthritis between 2010 and 2017. Patients with missing implant information, who received stemless humeral implants, or who received augmented glenoid implants, were excluded. Glenoid component designs used were categorized into 4 mutually exclusive treatment groups: polyethylene central-pegged ingrowth, polyethylene-metal hybrid, polyethylene all-cemented pegged, and polyethylene cemented keeled. Multivariable competing risk regression was used to evaluate the risk of glenoid loosening as a cause-specific revision by the glenoid component design.

RESULTS

Of the 5566 TSA included in the final cohort, 39.2% of glenoid implants were polyethylene central-pegged ingrowth, 31.1% were polyethylene-metal hybrid, 26.0% were polyethylene all-cemented pegged, and 3.6% were polyethylene cemented keeled. At 6-year final follow-up, 4.1% of TSA were revised for any cause, and 1.4% for glenoid loosening. Compared with the polyethylene central-pegged ingrowth design, no difference in glenoid loosening revision risk was observed for the polyethylene-metal hybrid design (hazard ratio [HR] = 1.15, 95% confidence interval [CI] = 0.42-3.20). However, both the polyethylene all-cemented pegged (HR = 2.48, 95% CI = 1.08-5.66) and polyethylene cemented keeled (HR = 3.84, 95% CI = 1.13-13.00) designs had higher risks for revision due to glenoid loosening.

CONCLUSIONS

We observed glenoid component designs to be associated with differential risks in revision due to glenoid loosening with polyethylene all-cemented pegged glenoids and polyethylene cemented keeled glenoids having higher risks when compared with polyethylene central-pegged ingrowth glenoids. Surgeons may want to consider the glenoid component design when performing anatomic TSA.

Osseous Integration of the Central Peg of an All-Polyethylene Glenoid With 3 Different Surgical Techniques

All-polyethylene glenoid components designed for osseous integration of the central peg can be placed with no graft (NG), autogenous bone graft (ABG), or demineralized bone matrix (DBM). The purpose of this study was to compare osseous integration with these 3 techniques. A randomized controlled trial was performed of 153 total shoulder arthroplasties using a pegged allpolyethylene glenoid component designed for osseous integration. Central peg treatment included NG, ABG, or DBM. The primary outcome was central peg osseous integration defined as bone presence between the central fins 1 year postoperatively. Central osseous integration was observed in 90% of cases treated with ABG, 68% of cases treated with DBM, and 68% of cases treated with NG (P=.022). Postoperative Wirth grading revealed radiolucency around the central peg (grade 1) in 2.4% of cases with ABG, 5.4% of cases with DBM, and 9.8% of cases with NG (P=.134). At short-term follow-up, osseous integration of the central peg of an all-polyethylene glenoid designed for bony growth between the central fins appears to be highest when treating the central peg with ABG compared with leaving the central peg untreated or using DBM. [Orthopedics. 2020;43(5):278-283.].

Loosening and revision rates after total shoulder arthroplasty: a systematic review of cemented all-polyethylene glenoid and three modern designs of metal-backed glenoid

BACKGROUND

Several modern designs of metal-backed glenoids (MBG) have been devised to overcome flaws such as loosening and a high failure rate. This review aimed to compare rates of complications and revision surgeries between cemented polyethylene glenoid (PEG) and three examples of modern MBG designs.

METHODS

Literature search was carried out using PubMed, Cochrane Library, EMBASE, and Google Scholar using MeSH terms and natural keywords. A total of 1186 articles were screened. We descriptively analyzed numerical data between the groups and statistically analyzed the categorical data, such as the presence of radiolucent line, loosening, and revision surgery (failure). Articles were divided into three groups based on follow-up duration: < 36-month, 36-72-month, and > 72-month subgroups.

RESULTS

This study included 35 articles (3769 shoulders); 25 on cemented PEG and ten on the modern MBG. Mean age was 66.4 (21-93) and 66.5 years (31-88). The mean duration of follow-up was 73.1 (12-211) and 56.1 months (24-100). Overall, the rate of the radiolucent line was 354/1302 (27%) and 47/282 (17%), the loosening rate was 465/3185 (15%) and 22/449 (5%), and the failure rate was 189/3316 (6%) and 11/457 (2%), for PEG and MBG, respectively. The results of < 36-month and 36-72-month subgroups showed lower rates of radiolucency and loosening in the cemented PEG group, but there was no significant difference in failure rate (P = 0.754 and 0.829, respectively). In the > 72-month subgroup, MBG was better in terms of loosening (P < 0.001) and failure rates (P = 0.006).

CONCLUSIONS

The modern MBG component, especially TM glenoid, seems to be a promising alternative to cemented PEGs, based on subgroup revision rates according to the follow-up duration and overall results of ROM and clinical scores. All polyethylene glenoids tend to increase loosening and failure over time. Three modern MBG designs seem to have no difference in failure, at least in the < 36-month and 36-72-month subgroups compared to the cemented PEG. More long-term follow-up studies on modern MBG should be ultimately conducted.

LEVEL OF EVIDENCE

Level IV, systematic review.

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

Background

Glenoid 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.

Methods

We 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.

Results

Forty-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).

Conclusion

Radiographic 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.

Short-term radiographic results of a cemented polyethylene keeled glenoid component with varying backside radiuses of curvature

BACKGROUND

This study analyzed the radiographic results of a cemented all-polyethylene keeled glenoid component available in different sizes and multiple backside radiuses of curvature.

METHODS

The study group consisted of 118 cases (114 patients). There were 63 women and 51 men. Mean age at the time of arthroplasty was 68 years (range, 51-85 years). True anterior-posterior radiographs obtained postoperatively and at the final follow-up were analyzed for implant seating and the occurrence of radiolucent lines. Glenoid morphology and fatty infiltration of the rotator cuff muscles were examined using computed tomography scans. Mean follow-up was 38 months (range, 24-70 months).

RESULTS

The mean radiolucent line score after surgery was 0.54 points (range, 0-3 points), and 90% had no or only 1 radiolucent line. At the final follow-up, the mean score was 1.06 points (range, 0-3 points), and 74% had no or only 1 radiolucent line. The score increased significantly over time (P < .001). No component was at risk for loosening. No correlation was found between patient age, sex, hand dominance, glenoid morphology, or fatty infiltration of the rotator cuff muscles and the occurrence of radiolucent lines.

CONCLUSION

In the short-term, the glenoid component analyzed in this study showed promising radiographic results, with a low number of radiolucent lines without failure. However, the mean radiolucent line score increased significantly over time, and long-term observations are necessary to confirm a possible advantage compared with older component designs.

What can be learned from an analysis of 215 glenoid component failures?

BACKGROUND

Glenoid component failure is a prevalent mechanical complication of anatomic total shoulder arthroplasty. The objective of this study was to identify surgeon-controlled factors that may be addressed to reduce the rate of glenoid component failure that is sufficiently symptomatic to merit surgical revision.

METHODS

We reviewed the clinical and radiographic features of 215 total shoulder arthroplasties that we revised for symptomatic glenoid component failure.

RESULTS

Glenoid component failure was associated with poor patient self-assessed shoulder function (mean Simple Shoulder Test score, 3.0 ± 2.7). These shoulders often showed multiple failure modes; 72% had glenoid component loosening, 69% had polyethylene wear, 51% had glenohumeral decentering, and 25% had humeral component loosening. Metal-backed/hybrid and keeled glenoid designs had higher rates of loosening (P = .010), malposition (P = .007), dislocation (P < .001), and early failure (P = .044) in comparison to pegged designs. Glenoid components with cement on the backside were more prevalent among those revised sooner than 5 years after the index surgery (P < .001).

CONCLUSIONS

Glenoid component failure remains a major cause of poor patient outcomes after total shoulder arthroplasty. The occurrence of severe glenoid component failure might be reduced by paying attention to glenoid component design and insertion technique, restoring the normal balance of the humeral head in the center of the glenoid, and considering a reverse total shoulder when the shoulder is unstable because of soft tissue deficiency.

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

Aims

Radiostereometric analysis (RSA) allows an extremely accurate measurement of early micromotion of components following arthroplasty.

Patients and Methods

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.

Results

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.

Conclusion

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.

What Change in American Shoulder and Elbow Surgeons Score Represents a Clinically Important Change After Shoulder Arthroplasty?

BACKGROUND

The American Shoulder and Elbow Surgeons (ASES) questionnaire was developed to provide a standardized method for evaluating shoulder function. Previous studies have determined the clinical responsiveness of this outcome measure for heterogenous populations or patients with nonoperatively treated rotator cuff disease. Currently, to our knowledge, no studies exist that establish the clinically relevant change in the ASES score after shoulder arthroplasty.

QUESTIONS/PURPOSES

We asked: (1) What are the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) for the ASES score after primary and reverse shoulder arthroplasties? (2) Are the MCID and SCB for the ASES score different between primary and reverse shoulder arthroplasties? (3) What patient-related factors are associated with achieving the MCID and SCB after total shoulder arthroplasty and reverse shoulder arthroplasty?

METHODS

A longitudinally maintained institutional shoulder arthroplasty registry was retrospectively queried for patients who underwent primary shoulder arthroplasty, including anatomic or reverse total shoulder arthroplasty from 2007 to 2013, with a minimum 2-year followup. Seven hundred ninety-four patients were identified and eligible; 304 of these patients did not have 2 years of followup or complete datasets, resulting in a study cohort of 490 patients (62% of the 794 potentially eligible). The MCID and SCB of the ASES score for these patients was calculated using an anchor-based method, using four different anchors measuring satisfaction with work, activities, overall, and activity from the SF-36. The MCID (anchored to somewhat satisfied) and SCB (very satisfied) of the ASES score were calculated for the entire cohort and stratified by arthroplasty type. Multivariate logistic regression of patient-related factors that influence the MCID and SCB achievement was performed.

RESULTS

The MCID for all patients combined ranged from 6.3 to 13.5; for the overall satisfaction anchor, the MCID was 13.5 ± 4.5 (95% CI, 4.8-22.3). The SCB for the overall cohort ranged from 12.0 to 36.6; for the overall satisfaction anchor, the SCB was 36.6 ± 3.8 (95% CI, 29.1-44.1). There were no differences in the MCID of the ASES score between anatomic and reverse shoulder arthroplasty for any of the anchors (p = 0.159-0.992) or the SCB for any of the anchors (p = 0.467-0.977). Combining anatomic and reverse shoulder arthroplasty in one group, higher preoperative ASES score (odds ratio [OR], 0.96; 95% CI, 0.94-0.98; p < 0.001), having a reverse shoulder arthroplasty (OR, 0.36; 95% CI, 0.16-0.85; p = 0.016), and having rheumatoid arthritis were independent predictors of not achieving an MCID for the ASES 2 years after surgery. Higher preoperative ASES score (OR, 0.91; 95% CI, 0.89-0.92; p < 0.001), a diagnosis of rotator cuff tear arthropathy (OR, 0.14; 95% CI, 0.07-0.30; p < 0.001), a diagnosis of back pain (OR, 0.42; 95% CI, 0.24-0.71); p = 0.002), and living alone (OR, 0.36; 95% CI, 0.19-0.69; p = 0.002) were all independent predictors of not achieving SCB after shoulder arthroplasty.

CONCLUSIONS

Patients with glenohumeral arthritis or rotator cuff tear arthropathy who undergo primary conventional total or reverse shoulder arthroplasty and have at least a nine-point improvement in their ASES score experience a clinically important change, whereas those who have at least a 23-point improvement in their ASES score experience a substantial clinical benefit. High preoperative function was associated with a decreased likelihood of achieving clinically important change after total shoulder arthroplasty.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Total shoulder replacement using a bone ingrowth central peg polyethylene glenoid component: a prospective clinical and computed tomography study with short- to mid-term follow-up

AIM OF THE STUDY

To assess the clinical and computed tomography (CT) outcomes of shoulder replacement with a novel bone ingrowth all-polyethylene glenoid component (APGC).

METHODS

Twenty-eight patients (30 shoulders) with osteoarthritis, mean age 62.3 years (range, 45-75), were implanted with the novel component between 2011 and 2013. Patients were evaluated by active range of motion (ROM), Constant-Murley score (CMS), simple shoulder test (SST), X-rays, and multidetector CT at two months and at a mean follow-up of 31 months (range, 24-39). Early and late follow-up CT scans were available for 21/30 shoulders.

RESULTS

Median ROM increased from 105 to 160° for anterior elevation, from 100 to 160° for lateral elevation, from 20 to 40° for external rotation, and from 2 to 10 points for internal rotation (all p < 0.001). CMS rose from 30 to 80.5 points and SST from 2.5 to 11 (both p < 0.0001). None of the glenoid components migrated. Progressive radiolucency was seen in 28/30 shoulders. There was a strong correlation between greater bone ingrowth (median Arnold score: 7) and lower radiolucency score (median Yian score: 2) at the last follow-up (p < 0.001). Osteolysis around the central peg was seen in two shoulders. There was no correlation between clinical scores and CT findings (p >0.05).

DISCUSSION

The partially cemented glenoid component for TSR assessed in this study resulted in satisfactory shoulder function at an early follow-up. The glenoid prosthesis was stable, with few radiolucent lines and good central peg bone ingrowth.

CONCLUSIONS

The satisfactory bone ingrowth documented on CT is encouraging and supports the use of the new prosthesis. Long-term follow-up studies can confirm if this device represents a rational alternative to fully cemented polyethylene glenoids.

Total shoulder arthroplasty with an augmented component for anterior glenoid bone deficiency

BACKGROUND

Glenoid bone loss is a challenging problem when performing total shoulder arthroplasty (TSA). Posterior glenoid bone deficiency is more common than anterior deficiency, and so the literature on methods to treat anterior glenoid deficiency in the setting of TSA is not common. The purpose of this case series was to describe preoperative factors, surgical technique, and clinical outcomes in select patients who underwent placement of an anteriorly augmented glenoid component during TSA.

METHODS

This was a retrospective case series of 5 patients who underwent TSA with an anteriorly augmented component. The medical records were reviewed, including preoperative demographics, clinical examination, radiographs, Penn Shoulder Score and American Shoulder and Elbow Surgeons score.

RESULTS

Preoperative diagnoses were anterior glenoid erosion in 2 patients, and 1 patient each with malunited glenoid fracture, nonunited glenoid fracture, and post-traumatic arthritis. The mean age at the time of surgery was 67.4 years (range, 53-75 years). No patient demonstrated radiographic or clinical signs of glenoid component loosening at final follow-up. Postoperative Penn Shoulder Scores averaged 84.4 points (range, 58-100 points), and postoperative American Shoulder and Elbow Surgeons scores averaged 88.0 points (range, 68-100 points). Average postoperative active forward elevation was 140° (range, 80°-170°), and active external rotation was 29° (range 10°-45°). There were no dislocations or revision surgeries at an average of 33.2 months (range, 21.9-43.2 months) after surgery.

CONCLUSION

In the short term, glenohumeral arthrosis in the setting of anterior glenoid deficiency can be treated with an anteriorly augmented glenoid component. Further follow-up and a larger series of patients are necessary to determine the long-term outcomes and complications associated with this technique.