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

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.

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.

Complications After Anatomic Shoulder Arthroplasty: Revisiting Leading Causes of Failure

For practicing shoulder arthroplasty surgeons, it is advisable to consider a breadth of data sources concerning complications and outcomes. Although published series from high-volume centers are the primary source of data, these results may not be generalizable to a wide range of practice settings. National or health system-specific registry and medical device databases are useful adjuncts to assess the changing complication profile of shoulder arthroplasty, as well as to understand the complications specific to certain implants or implant types. To reduce the risk of postoperative complications, surgeons must have a clear understanding of the most common modes of failure.

Medium-Term Clinical and Radiographic Results of an All-Polyethylene, Pegged, Bone-Ingrowth Glenoid Component: A Concise Follow-up of a Previous Report

ABSTRACT

We previously reported the mean 4-year outcomes of anatomic total shoulder replacement using an all-polyethylene, pegged, hybrid-fixation (bone ingrowth and cement) glenoid component. In the present study, we report on that patient cohort after another 4 years of follow-up (mean, 101 months; range, 77 to 146 months). At that time, the median American Shoulder and Elbow Surgeons (ASES) score was 92 points (interquartile range [IQR], 81.7 to 98.3) and the median Oxford Shoulder Score was 47 points (IQR, 41 to 48). Osseointegration, demonstrated by bone ingrowth between the flanges on the central peg as seen on coronal computed tomography (CT), was complete in 75% of the shoulders, partial in 21%, and absent in 4%. There were radiolucent lines at the bone-prosthesis interface on CT, with a median Yian score of 1 (IQR, 0 to 2; range, 0 to 18). The conclusion in the present study was that shoulder arthroplasty with an all-polyethylene, hybrid-fixation (bone ingrowth and cement) pegged glenoid component has durable clinical and radiographic outcomes at medium-term follow-up.

LEVEL OF EVIDENCE

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

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.

Integração óssea e prevalência de linhas radiotransparentes ao redor dos pinos de componentes glenoidais minimamente cimentados na artroplastia total de ombro

Objectives  Glenoid component failure is the main cause of total shoulder arthroplasty (TSA) revision, and component design seems to influence the failure rate. The aim of the present study was to clinically and radiographically (through X-rays and computed tomography scan) evaluate the results of TSA using a minimally cemented glenoid component.

Methods  Total should arthroplasties performed using the minimally cemented Anchor Peg (DuPuy Synthes, Warsaw, IN, USA) glenoid component between 2008 and 2013 were evaluated. University of California at Los Angeles (UCLA) scores were calculated, and standardized plain film and computed tomography images were obtained, at a minimum follow-up of 24 months. The presence of bone between the fins of the central component peg, which indicates its integration, was assessed on the images, as well the presence of radiolucent lines around the glenoid component.

Results  Nineteen shoulders in 17 patients were available for evaluation. According to the UCLA score, clinical results were satisfactory in 74% of cases and fair in 21% of cases. One patient had a poor result. Component integration was found in 58% of patients (total in 42% and partial in 16%). Radiolucent lines were observed in 52% of cases. No relationship was detected between component integration and clinical results.

Conclusion  Satisfactory clinical results were achieved in most patients undergoing TSA using a minimally cemented glenoid component. Radiolucent lines around the glenoid component are common, but do not interfere with the clinical results.

Level of evidence IV; Case series; Treatment study.

Humeral stem lucencies correlate with clinical outcomes in anatomic total shoulder arthroplasty

Background

Humeral stem lucencies are uncommon after uncemented anatomic total shoulder arthroplasty (aTSA), and their clinical significance is unknown. This study compares clinical outcomes of aTSA with and without humeral stem lucencies.

Methods

Two-hundred eighty aTSAs using an uncemented grit-blasted metaphyseal-fit humeral stem between 2005 and 2013 were retrospectively evaluated for radiographic humeral stem lucencies. All shoulders were evaluated at a minimum 5-year follow-up from a multicenter database. Clinical outcomes included range of motion (ROM) and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, Constant score, University of California-Los Angeles Shoulder Score (UCLA), Simple Shoulder Test (SST), and Shoulder Pain and Disability Index (SPADI) scores. Postoperative radiographs were evaluated and complications were recorded.

Results

Two-hundred forty-three humeral stems showed no radiolucent lines. Among the 37 humeral stems with lucent lines, lines were most common in zones 8, 4, 7, and 3. Preoperative ROM and functional outcomes were similar between groups. Postoperative change in outcomes exceeded the minimal clinically important difference (MCID) for all ROM and outcomes in both groups. Postoperative change between groups showed no significant difference in ROM or outcome scores, but improved mean abduction exceeded the MCID in the patients without humeral lines. The complication rate after omitting patients with humeral loosening was higher in patients with humeral lucencies, as was the revision rate. There was also a higher glenoid-loosening rate in patients with humeral lucencies.

Conclusion

Humeral lucent lines after uncemented stemmed aTSA have a small negative effect on ROM and functional outcomes compared with patients without lucent humeral lines, which may not be clinically significant. The complication and revision rates were significantly higher in patients with humeral lucencies.

Uncemented fixation of a monoblock ingrowth polyethylene glenoid: early follow-up

BACKGROUND

Traditional monoblock pegged glenoid components are implanted with cement, increasing operative time and potentially violating more bone than those inserted without cement. We study the early radiographic loosening and reoperation rate following uncemented fixation of a hybrid cage monoblock polyethylene glenoid component.

METHODS

Between 2013 and 2015, a total of 51 shoulders underwent anatomic shoulder arthroplasty (TSA) using a hybrid ingrowth cage polyethylene glenoid component by a single surgeon, with a minimum follow-up of 2 years. In all cases, the glenoid component was placed without cement. Mean follow-up was 33 months (range, 24-57). The primary outcome was Lazarus scale-assessed radiographic loosening. Secondary outcomes included reoperation, range of motion (ROM), and patient-reported outcome measures (PROMs).

RESULTS

Twelve glenoid components (24%) had radiolucent lines. Glenoid lines were rated grade 1, grade 2, and grade 5 (6, 4, and 2 shoulders, respectively). Six shoulders (12%) had humeral lucent lines. Two shoulders (4%) underwent reoperation, only 1 of these occurring due to isolated failure of the glenoid component. As a group, mean ROM and PROMs improved significantly compared with preoperative values and exceeded the minimal clinically important difference.

CONCLUSION

Glenoid loosening remains a major concern at mid- to long-term follow-up of TSA. Placement of this hybrid cage monoblock polyethylene glenoid component in a completely uncemented fashion does not lead to early clinical loosening, after which bony ingrowth into the central cage can be expected. Uncemented fixation of this hybrid cage component appears to be a safe treatment option for patients undergoing primary TSA.

Pre-operative factors affecting the indications for anatomical and reverse total shoulder arthroplasty in primary osteoarthritis and outcome comparison in patients aged seventy years and older

BACKGROUND

We evaluated the pre-operative factors affecting anatomical and reverse total shoulder arthroplasty (TSA and RTSA) indications in primary osteoarthritis and compared outcomes in patients aged 70 years and older.

METHODS

Fifty-eight patients received a TSA with an all-polyethylene glenoid component (APGC) or an RTSA with/without glenoid lateralization and the same curved short-stem humeral component. Active anterior and lateral elevation (AAE, ALE), internal and external rotation (IR, ER), pain, and the Constant-Murley score (CS) were recorded pre and post-operatively. Pre-operative rotator cuff (RC) fatty infiltration (FI) and modified Walch glenoid morphology were assessed. Humeral and glenoid component radiological outcomes were recorded.

RESULTS

RTSA were older than TSA patients (p = 0.006), had lower pre-operative AAE (p < 0.001), ALE (p < 0.001), IR (p = 0.002), pain (p = 0.008) and CS (p < 0.001), and greater supraspinatus FI (p < 0.001). At a mean of 28.8 months, both implants yielded significantly different post-operative scores and similar complication rates. Both groups achieved similar post-operative AAE, ER, and IR; ALE was higher in TSA (p = 0.006); and AAE and ALE delta scores were higher in RTSA (p = 0.045 and p = 0.033, respectively). Radiolucent line rates were higher around the TSA APGC than the RTSA baseplate (p = 0.001). High-grade RC FI adversely affected mobility improvement. Humeral cortical thinning was significantly higher in TSA (p = 0.001).

CONCLUSION

RTSA patients were older, had poorer pre-operative active mobility, and had greater RC FI than TSA. Both devices provided good mid-term clinical and ROM improvement.

Glenoid component lucencies are associated with poorer patient-reported outcomes following anatomic shoulder arthroplasty

BACKGROUND

High rates of radiographic glenoid loosening following anatomic total shoulder arthroplasty (TSA) are documented at midterm follow-up. Small studies remain conflicted on the impact of lucent lines on clinical outcomes. This study assesses the impact of radiolucent lines on function and patient-reported outcomes (PROs) following TSA.

METHODS

We retrospectively evaluated 492 primary TSAs performed between February 2005 and April 2016. Radiographs were evaluated for glenoid loosening according to the Lazarus grade at a mean of 5.3 years (range, 2-12 years). Clinical outcome measures included range of motion and American Shoulder and Elbow Surgeons, Constant, University of California-Los Angeles, Simple Shoulder Test, and Shoulder Pain and Disability Index scores. Outcomes were compared between patients with and patients without glenoid lucent lines and in relation to lucency grade.

RESULTS

At most recent follow-up, 308 glenoids (63%) showed no radiolucent lines (group 0) and 184 demonstrated peri-glenoid lucencies (group 1). The groups were similar regarding age, sex, body mass index, comorbidities, and prior surgery. At follow-up, group 1 demonstrated significantly lower improvements in forward elevation (P = .02) and all PROs (P ≤ .005). Subgroup analysis by radiolucency grade showed that forward elevation diminished with increasing radiolucent score and exceeded the minimal clinically important difference (MCID) above grade 2 lucencies. A similar decline in PROs was observed with increasing lucency grade. These differences did not exceed the MCID below grade 5 lucencies.

DISCUSSION

Peri-implant glenoid lucencies following TSA are associated with lower forward elevation and PROs. Lucencies above grade 2 are associated with clinically important losses in overhead motion. However, differences below the MCID are maintained for PROs below grade 5 glenoid lucencies.

Journey of the glenoid in anatomic total shoulder replacement

Anatomic total shoulder arthroplasty (TSR) has been shown to generate good to excellent results for patients with osteoarthritis and a functioning rotator cuff. Many studies have reported that the glenoid component loosening and failure remain the most common long-term complication of total shoulder arthroplasty. The approach to glenoid component is critical because a surgeon should consider patient-specific anatomy, preserving bone stock and joint line restoration, for a good and durable shoulder function. Over the years, different glenoid design and materials have been tried in various configurations. These include cemented polyethylene, uncemented metal-backed and hybrid implants. Although advances in biomechanics, design and tribology have improved our understanding of the glenoid, the journey of the glenoid component in anatomic total shoulder arthroplasty has not yet reached its final destination. This article attempts to describe the evolution of the glenoid component in anatomic TSR and current practice.

Assessment of anatomical and reverse total shoulder arthroplasty with the scapula-weighted Constant-Murley score

AIM OF THE STUDY

To evaluate total (TSA) and reverse total shoulder arthroplasty (RTSA) using the Constant-Murley score (CMS) and the scapula-weighted (SW) CMS, an integrated outcome measure that takes into account the compensatory movements of the scapula.

METHODS

Twenty-five consecutive patients, 12 with TSA and 13 with RTSA, underwent kinematic analysis before and after shoulder replacement. Measurements included flexion (FLEX) and abduction (ABD) for the humerus and Protraction-Retraction (PR-RE), Medio-Lateral rotation (ME-LA), and Posterior-Anterior tilting (P-A) for the scapula. They were recorded at baseline (T0) and at six (T1) and 12 months (T2). Reference data were obtained from 31 control shoulders.

RESULTS

At T1, differences in CMS and SW-CMS were not significant in either group, whereas values at T2 were significantly lower in RTSA patients (p = 0.310 and p = 0.327, respectively). In TSA shoulders, the compensatory scapular movements in FLEX were all reduced from T0 to T2, whereas P-A was increased in ABD. In RTSA patients, the compensatory scapular movements in FLEX showed a general reduction at T1, with an increase in P-A at T2, whereas in ABD, all increased at T1 and decreased at T2 except for P-A, which did not decrease.

DISCUSSION

The SW-CMS showed that the physiological scapulothoracic motion was not restored in TSA and RTSA patients; it may be used as a reference for the gradual progression of deltoid and scapular muscle rehabilitation.

CONCLUSIONS

The worse CMS and SW-CMS scores found in RTSA patients at six months may be due to the biomechanics of the reverse prosthesis and to the weakness of deltoid and periscapular muscles.

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.