Improved survival for anatomic total shoulder prostheses

The Delta III and Delta Xtend reverse shoulder arthroplasty-risk of revision and failure mechanisms: a report on 3650 cases from the Norwegian Arthroplasty Register 1994-2021

BACKGROUND

The Delta reverse shoulder arthroplasty (RSA) is commonly used worldwide and is the most frequently used RSA in Norway. The aim of this registry-based study was to report 10- and 20-year implant survival, risk of revision, and reasons for revision in 2 consecutive time periods for Delta III (1994-2010) and Delta Xtend (2007-2021) prostheses.

METHODS

We included 3650 primary RSAs reported to the Norwegian Arthroplasty Register: 315 Delta III (42% cemented stems) and 3335 Delta Xtend (88% cemented stems). We used Kaplan-Meier analyses to investigate implant survival. The reasons for revision were compared for the 2 designs and fixation technique. Factors that could influence the risk of revision, such as implant design, fixation technique, and patient factors, were investigated using Cox regression analyses with adjustments for age, sex, and diagnosis.

RESULTS

Patients operated with Delta III were more likely to be diagnosed with inflammatory disease or fracture sequela, whereas acute fracture, osteoarthritis, and cuff arthropathy were the most frequent indications for Delta Xtend. Ten-year survival was 93.0% (95% confidence interval [CI]: 87.0-99.0) (cemented stem) and 81.6% (95% CI: 75.3-87.9) (uncemented stem) for Delta III and 94.7% (95% CI: 93.3-96.1) (cemented stem) and 95.7% (95% CI: 88.3-100) (uncemented stem) for Delta Xtend. Twenty-year survival for Delta III (uncemented stem) was 68.2% (95% CI: 58.8-77.6). Compared with DeltaXtend (cemented stem) at 10-year follow-up, we found a higher risk of revision for Delta III (uncemented stem) (hazard ratio [HR]: 2.9, 95% CI: 1.7-5.0), whereas no significant difference was found for Delta III (cemented stem) and Delta Xtend (uncemented stem). The most common reason for revision of Delta III (uncemented stem) was glenoid loosening followed by deep infection and instability. Instability was the most frequent revision cause for Delta Xtend (both cemented and uncemented stem). Men had an overall higher revision risk than women (HR: 2.8 [95% CI: 2.0-3.9]), and patients with fracture sequela had increased risk for revision (HR: 2.8, 95% CI: 1.7-4.7) compared with patients with osteoarthritis.

DISCUSSION

We found that Delta III (uncemented stem) had a higher risk of revision compared with Delta Xtend (cemented stem). The risk of revision for glenoid component loosening was lower for Delta Xtend, but revisions due to instability/dislocation are still a concern. This register study cannot determine whether the differences found were caused by differences in implant design or other factors that changed during the study period. Risk of revision may have been affected by the indication for primary operation.

Limited value of current shoulder arthroplasty registries in evidence-based shoulder surgery: a review of 7 national registries

National shoulder arthroplasty registries are currently used to assess incidence, indication, type of prosthesis and revision, but they seem to lack sufficient information to lead to evidence based decision-making in shoulder surgery. There appears to be a large difference in registered parameters and outcome measurement per country. First we investigated whether existing registries have sufficient common datasets to enable pooling of data. Second, we determined whether known risk factors for prosthetic failure are being recorded. Through a non-systematic literature review studies on registries were analyzed for included parameters. Seven national registries were scrutinized for the data collected and these were classified according to categories of risk factors for failure: patient-, implant and surgeon related, and other parameters. This shows a large heterogeneity of registered parameters between countries. The majority of parameters shown to be relevant to outcome and failure of shoulder prostheses are not included in the studied registries. International agreement on parameters and outcome measurement for registries is paramount to enable pooling and comparison of data. If we intend to use the registries to provide us with evidence to improve prosthetic shoulder surgery, we need adjustment of the different parameters to be included.

A Comparison of Revision Rates for Osteoarthritis of Primary Reverse Total Shoulder Arthroplasty to Primary Anatomic Shoulder Arthroplasty with a Cemented All-polyethylene Glenoid: Analysis from the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND

There has been decreased use of anatomic total shoulder arthroplasty (aTSA) because reverse TSA (rTSA) is increasingly being used for the same indications. Although short-term studies generally have not found survivorship differences between these implant designs, these studies are often small and their follow-up is limited to the short term. Likewise, the degree to which patient characteristics (such as gender, age, and American Society of Anesthesiologists [ASA] score) may or may not be associated with survivorship differences calls for larger and longer-term studies than is often possible in single-center designs. Large national registry studies may be able to help answer these questions.

QUESTIONS/PURPOSES

By analyzing a large Australian registry series of primary aTSAs with cemented all-polyethylene glenoids and rTSA for osteoarthritis (OA), we asked: (1) Is the revision risk for OA higher for aTSA with all-polyethylene glenoids or for rTSA, adjusting for patient characteristics such as age, gender, ASA score, and BMI? (2) Is the patient's gender associated with differences in the revision risk after controlling for the potentially confounding factors of age, ASA score, and BMI?

METHODS

In this comparative, observational registry study performed between January 1, 2015, and December 31, 2019, all primary aTSAs with all-polyethylene glenoids and rTSA for OA as determined by the treating surgeon and reported to our national registry formed two groups for analysis. The study period was set to time-match for the collection of ASA score and BMI in 2012 and 2015, respectively. Our registry enrolls more than 97% of all shoulder arthroplasties undertaken in Australia. There were 29,294 primary shoulder arthroplasties; 1592 hemiarthroplasties, 1876 resurfacing and stemless shoulders, 269 stemmed, and 11,674 reverse shoulder arthroplasties were excluded for other diagnoses. A total of 1210 metal-backed glenoids in stemmed aTSA for OA were excluded. A total of 3795 primary aTSAs with all-polyethylene glenoids and 8878 primary rTSAs for OA were compared. An aTSA with an all-polyethylene glenoid and rTSA were more likely to be performed in women (56% and 61% of patients, respectively). The mean age was 69 ± 8 years for aTSA with all-polyethylene glenoids and 74 ± 8 years for rTSA. One aTSA for OA was performed in a patient with an unknown glenoid type. The ASA score (n = 12,438) and BMI (n = 11,233) were also recorded. The maximum follow-up was 5 years for both groups, and the mean follow-up was 2.6 ± 1.4 years for aTSA with all-polyethylene glenoids and 2.1 ± 1.4 years for rTSA. The endpoint was time to revision (all causes), and the cumulative percent revision was determined using Kaplan-Meier estimates of survivorship (time to revision) and HRs from Cox proportional hazard models that were adjusted for age, gender, ASA score, and BMI category.

RESULTS

Overall, there were no differences in the 4-year cumulative percent revision between the groups; the 4-year cumulative percent revision was 3.5% for aTSA with all-polyethylene glenoids (95% CI 2.9%-4.2%) and 3.0% for rTSA (95% CI 2.6%-3.5%). There was an increased risk of revision of rTSA compared with aTSA using all-polyethylene glenoids in the first 3 months (HR 2.17 [95% CI 1.25-3.70]; p = 0.006, adjusted for age, gender, ASA score, and BMI). After that time, there was no difference in the rate of revision, with the same adjustments. In the first 3 months, men undergoing rTSA had a higher rate of revision than men with aTSA using all-polyethylene glenoids (HR 4.0 [95% CI 1.72-9.09]; p = 0.001, adjusted for age, BMI, and ASA). There was no difference between men in the two groups after that time. Women with aTSA using all-polyethylene glenoids were at a greater risk of revision than women with rTSA from 3 months onward (HR 2.77 [95% CI 1.55-4.92]; p < 0.001, adjusted for age, BMI, and ASA), with no difference before that time.

CONCLUSION

Given the absence of survivorship differences at 4 years between rTSA and aTSA, but in light of the differences in the revision risk between men and women, surgeons might select an aTSA with an all-polyethylene glenoid to treat OA, despite the current popularity of rTSA. However, there are survivorship differences between genders. Future studies should evaluate whether our comparative findings are replicated in men and women undergoing aTSA with all-polyethylene glenoids and rTSA for primary diagnoses such as rheumatoid arthritis or post-traumatic arthritis, and whether there are functional differences between the two implant designs when used for OA.

LEVEL OF EVIDENCE

Level III, therapeutic study.

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

BACKGROUND

Total shoulder arthroplasty is an established treatment with the commonest cause of failure loosening of the glenoid component. Hydroxyapatite metal-backed glenoid components could offer better survivorship due to improved fixation. The aim of this study was to investigate periprosthetic radiolucency rates associated with an uncemented, metal-backed polyethylene glenoid component with medium-term results.

METHODS

A single centre retrospective study examining radiological outcomes of the Epoca metal-backed glenoid component. Radiographs were analysed for post-operative adequacy of glenoid seating and radiographs at follow-up assessed for periprosthetic lucencies and any revision procedures were recorded.

RESULTS

Forty-one patients were followed up with a mean follow-up time of 5.5 years (3-8 years). Primary indication for total shoulder arthroplasty was osteoarthritis (80%). Mean age was 69 years (53-86 years). Ninety-five per cent of glenoid components were completely seated. At follow-up six patients had undergone revision (14.6%). Thirty of the remaining patients (86%) did not demonstrate any radiolucency on follow-up radiographs. Complete glenoid seating post-operatively was associated with lower rate of subsequent radiolucency and revision (P < 0.01).

CONCLUSION

Low rates of radiolucency at medium-term follow-up with an uncemented metal-backed glenoid, however significant rates of revision. Complete seating of the glenoid component was associated with lower rates of radiolucency and revision.

Is preoperative glenoid bone mineral density associated with aseptic glenoid implant loosening in anatomic total shoulder arthroplasty?

Background

Aseptic loosening of glenoid implants is the primary revision cause in anatomic total shoulder arthroplasty (aTSA). While supported by biomechanical studies, the impact of glenoid bone quality, more specifically bone mineral density (BMD), on aseptic glenoid loosening remains unclear. We hypothesized that lower preoperative glenoid BMD was associated with aseptic glenoid implant loosening in aTSA.

Methods

We retrospectively included 93 patients (69 females and 24 males; mean age, 69.2 years) who underwent preoperative non-arthrographic shoulder computed tomography (CT) scans and aTSA between 2002 and 2014. Preoperative glenoid BMD (CT numbers in Hounsfield unit) was measured in 3D using a reliable semi-automated quantitative method, in the following six contiguous volumes of interest (VOI): cortical, subchondral cortical plate (SC), subchondral trabecular, and three successive adjacent layers of trabecular bone. Univariate Cox regression was used to estimate the impact of preoperative glenoid BMD on aseptic glenoid implant loosening. We further compared 26 aseptic glenoid loosening patients with 56 matched control patients.

Results

Glenoid implant survival rates were 89% (95% confidence interval CI, 81–96%) and 57% (41–74%) at 5 and 10 years, respectively. Hazard ratios for the different glenoid VOIs ranged between 0.998 and 1.004 (95% CI [0.996, 1.007], p≥0.121). Only the SC VOI showed significantly lower CTn in the loosening group (622±104 HU) compared with the control group (658±88 HU) (p=0.048), though with a medium effect size (d=0.42). There were no significant differences in preoperative glenoid BMD in any other VOI between patients from the loosening and control groups.

Conclusions

Although the preoperative glenoid BMD was statistically significantly lower in the SC region of patients with aseptic glenoid implant loosening compared with controls, this single-VOI difference was only moderate. We are thus unable to prove that lower preoperative glenoid BMD is clearly associated with aseptic glenoid implant loosening in aTSA. However, due to its proven biomechanical role in glenoid implant survival, we recommend extending this study to larger CT datasets to further assess and better understand the impact of preoperative glenoid BMD on glenoid implant loosening/survival and aTSA outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-020-03892-0.

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

BACKGROUND

Total shoulder arthroplasty has shown good clinical efficacy in treating primary and secondary degenerative conditions of the glenohumeral joint. Glenoid loosening, however, remains the commonest cause of failure. The purpose of this study was to investigate the rate of radiographic periprosthetic lucency associated with the use of an uncemented, pegged, metal-backed polyethylene glenoid component.

MATERIALS AND METHODS

A retrospective, single-centre study using the Epoca (Synthes, Paoli, Pennsylvania) metal-backed glenoid component. Operations were performed by two experienced consultant upper limb surgeons. Radiographs were analysed for immediate post-operative component seating and periprosthetic radiolucent lines at predefined regular post-operative intervals. Intra- and inter-observer reliability was assessed to improve validity of results.

RESULTS

Mean age and follow-up was 72 (48-91) years and 2.5 years (2-5), respectively. Main indications for total shoulder arthroplasty were primary osteoarthritis, rheumatoid arthritis, revision for failed hemi-arthroplasty and acute fracture. Ninety-six per cent of components were completely seated post-operatively. Fifty-four (95%) of the 57 shoulders had no periprosthetic radiolucent lines at most recent follow-up. Complete post-operative glenoid seating was significantly associated with the absence of later periprosthetic radiolucency (p < 0.01).

CONCLUSION

This study reports low early radiolucency rates with the pegged, uncemented, metal-backed polyethylene glenoid prosthesis used. Excellent post-operative glenoid seating is associated with a significantly lower rate of radiolucency. Longer follow-up data are required to confirm these early promising results.Level of evidence: Therapeutic, level IV.

6-Year clinical results and survival of Copeland Resurfacing hemiarthroplasty of the shoulder in a consecutive series of 279 cases

BACKGROUND

Medium-term clinical results and survival of the Copeland resurfacing hemiarthroplasty of the shoulder (CRHA) in a large consecutive group are presented with a comparison of outcomes for underlying pathologies.

METHODS

A consecutive series of patients undergoing CRHA over 14 years was retrospectively analysed with no exclusions. Patients had a minimum 2-year follow-up by an independent assessor. Functional outcome was assessed using the Oxford Shoulder Score (OSS) and Constant-Murley Score (CMS). Pain and satisfaction was assessed using a visual analogue score.

RESULTS

279 CRHAs were performed in 242 patients between 2002 and 2016. The mean follow-up was 6 years. The indication for surgery was osteoarthritis (OA) in 212, inflammatory arthropathy (RA) in 35, rotator cuff tear arthropathy (CTA) in 22 and avascular necrosis (AVN) in 2. For the OA group, 5-year survival was 90%, 10-year survival was 83% and mean survival was 13.2 years (95% CI 12.5-13.9). The mean OSS was 35.0 and mean CMS 49.9. CRHA for CTA had significantly poorer (p < 0.001) 5-year survival (55%), 10-year survival (41%) and mean survival (5.9 years, 95% CI 4.7-7.2). Mean OSS was 23.6 and mean CMS 30.3, which was poorer than for OA (p < 0.001). A subgroup analysis of OA patients found significantly better survival (p = 0.013) in those aged over 65 years but no difference in functional outcome.

CONCLUSION

CRHA remains a reasonable option for OA in patients with an intact rotator cuff and with sufficient bone stock, especially in those aged over 65 years. With poorer functional outcomes and survival, CRHA should not be offered in those with CTA.

LEVEL OF EVIDENCE

Level III (retrospective comparative study).

In vivo corrosion and damages in modular shoulder prostheses

Wear and corrosion at taper junctions of orthopaedic endoprostheses remain of great concern and are associated with adverse clinical reactions. Whereas tribocorrosion of hip tapers was extensively investigated, there is only little knowledge regarding the clinical performance of modular total shoulder prostheses. This retrieval study evaluated 35 modular taper junctions of anatomical shoulder explants using stereomicroscopy, confocal microscopy, as well as optical and scanning electron microscopy to determine the damage modes as well as the effects of taper topography and alloy microstructure. Among all humeral head tapers, 89% exhibited material degradation. Different overlapping wear mechanisms were identified such as plastic deformation, adhesive material transfer, microploughing, and fretting damage. Only CoCrMo cast alloy heads showed a susceptibility to electrochemically dominated fretting in comparison to CoCrMo wrought alloy. Moreover, corundum blasted stem tapers show a significantly increased incidence rate for microploughing. To date, this is the most comprehensive study on the damage types of modular taper junctions of anatomical shoulder arthroplasty proving the existence of fretting even on less weight-bearing implants. This study revealed critical fretting factors, such as the surface finish and the alloy type that are essential for the development of countermeasures that avoid any taper corrosion.

A comparison of the minimum data sets for primary shoulder arthroplasty between national shoulder arthroplasty registries. Is international harmonization feasible?

The aims of this study were to identify the common components of the Minimum Data Set (MDS) of current national shoulder arthroplasty registries that could be pooled for analysis; and to determine whether further harmonisation of data collection across these registries would be feasible. Copies of primary shoulder arthroplasty MDS forms, annual reports, and other publications from national shoulder arthroplasty registries were identified using internet search engines up to November 2016. Data relating to local or regional registries was excluded. There were nine national shoulder arthroplasty registries reporting a total of 97,388 primary shoulder replacements. All minimum data sets included patient identifiers, date of surgery, implant identification, laterality of surgery, indication and mode of implant fixation. At least 6 registries had common options within the categories of indication, implant fixation and previous operations. Most discrepancies were seen in categories for additional interventions, outcome measures, and intra-operative complications. As numbers within individual registries are relatively small, international collaboration would harness the global strength of knowledge and experience in shoulder replacement. Several similarities were identified between the current national registries that could become unified with only minor changes by a few registries, highlighting the potential feasibility of MDS harmonisat.

Low revision rate despite poor functional outcome after stemmed hemiarthroplasty for acute proximal humeral fractures: 2,750 cases reported to the Danish Shoulder Arthroplasty Registry

Background and purpose - The revision rate of stemmed hemiarthroplasty (SHA) for acute proximal humeral fractures is low, but does not necessarily reflect the functional outcome. We report the revision rate of SHA for acute proximal humeral fractures and the proportion of arthroplasties that are not revised despite low functional outcome scores. Patients and methods - The Danish Shoulder Arthroplasty Registry was used to identify all patients with a proximal humeral fracture that was treated with a SHA between January 1, 2006 and December 31, 2015. Information on demographics, surgical procedures, and revisions was collected by the registry. The Western Ontario Osteoarthritis of the Shoulder (WOOS) index at 1 year was used as functional outcome score. We converted the score to a percentage of a maximum score with 100 being the best. Results - 2,750 SHAs in 2,719 patients were included. Mean age was 72 years (SD 11); 79% were women. Mean WOOS at 1 year was 55 (SD 26). A total of 101 (4%) arthroplasties were revised, and the 10-year cumulative implant survival rate was 95%. The Cox regression model showed a statistically significant impact on implant survival of age, but not of sex or arthroplasty brand. A WOOS score below 30 and 50 was reported in 11% and 25% of patients, respectively. Interpretation - We found a high implant survival rate, but also a high proportion of patients with a low functional outcome score 1 year after surgery.

Return to work after shoulder arthroplasty: a systematic review and meta-analysis

BACKGROUND

With the rising incidence of shoulder arthroplasty, there is increasing emphasis on improving functional outcomes and ability to return to work (RTW). The purpose of this study was to determine the rate of RTW after shoulder arthroplasty.

METHODS

This systematic review and meta-analysis were performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A literature search of 4 electronic databases was performed from database conception through April 2018 to identify studies reporting data on RTW after shoulder arthroplasty. The primary outcome was the rate of RTW after shoulder arthroplasty. Random-effects meta-analysis was used to pool the rate of RTW across studies.

RESULTS

Seven studies were reviewed, including 447 patients at an average follow-up of 4.4 years (range, 1.0-12.6 years). The overall rate of RTW was 63.6% (95% confidence interval, 58.8%-68.2%) at a mean 2.3 months postoperatively (range, 0.3-24.0 months). RTW was significantly lower for patients with heavy-intensity occupations vs. all intensity types (61.7% vs. 67.6%; P = .04). RTW did not differ between anatomic total shoulder arthroplasty (63.4%) and hemiarthroplasty (66.1%) or reverse total shoulder arthroplasty (61.5%; P = .53). There were no significant differences in RTW among underlying diagnoses (osteoarthritis, 64.4%; cuff tear arthropathy, 65.6%; proximal humerus fracture, 69.1%; P = .41) or by workers' compensation status (61.2% vs. 65.3%; P = .41).

CONCLUSIONS

A majority of patients return to work after shoulder arthroplasty at an average of 2.3 months postoperatively. Those with heavy-intensity occupation return at significantly lower rates, whereas no differences in RTW by arthroplasty type, underlying diagnosis, or workers' compensation were found.

A population-based comparison of joint survival of hemiarthroplasty versus total shoulder arthroplasty in osteoarthritis and rheumatoid arthritis

Aims

Few studies have compared survivorship of total shoulder arthroplasty (TSA) with hemiarthroplasty (HA). This observational study compared survivorship of TSA with HA while controlling for important covariables and accounting for death as a competing risk.

Patients and Methods

All patients who underwent shoulder arthroplasty in Ontario, Canada between April 2002 and March 2012 were identified using population-based health administrative data. We used the Fine–Gray sub-distribution hazard model to measure the association of arthroplasty type with time to revision surgery (accounting for death as a competing risk) controlling for age, gender, Charlson Comorbidity Index, income quintile, diagnosis, and surgeon factors.

Results

During the study period, 5777 patients underwent shoulder arthroplasty (4079 TSA, 70.6%; 1698 HA, 29.4%), 321 (5.6%) underwent revision, and 1090 (18.9%) died. TSA patients were older (TSA mean age 68.4 years (sd 10.2) vs HA mean age 66.5 years (sd 12.7); p = 0.001). The proportion of female patients was slightly lower in the TSA group (58.0% vs 58.4%). The adjusted association between surgery type and time to shoulder revision interacted significantly with patient age. Compared with TSA patients, revision was more common in the HA group (adjusted-health ratio (HR) 1.214, 95% confidence interval (CI) 0.96 to 1.53) but this did not reach statistical significance.

Conclusion

Although there was a trend towards higher revision risk in patients undergoing HA, we found no statistically significant difference in survivorship between patients undergoing TSA or HA. Cite this article: Bone Joint J 2019;101-B:454–460.

Revision of Failed Resurfacing Hemiarthroplasty: Midterm Results, Survival, and Group Comparison

Shoulder arthroplasty is a valuable option for treating glenohumeral osteoarthritis. Revision surgery for a failed shoulder arthroplasty is associated with difficult procedures, complications, and worse outcomes. Compared with a total joint arthroplasty, a resurfacing prosthesis has the supposed advantages of limited perioperative complications and little bone loss during revision. The aim of this study was to describe patient-reported outcome measures of revision surgery from failed uncemented Global CAP (DePuy, Warsaw, Indiana) resurfacing hemiarthroplasty to total shoulder or reverse shoulder arthroplasty. Eleven patients from 2 collaborating institutes had a failed resurfacing prosthesis. Revision surgery was performed to total shoulder prosthesis in 7 patients and to reverse shoulder prosthesis in 3 patients. Data were missing for 1 patient. Outcomes were monitored using the Constant-Murley score, Dutch Simple Shoulder Test, Short Form-12, visual analog scale for pain, and physical examination. Mean time to revision was 54 months (SD, 15.6 months). No perioperative complications occurred. At 42 months of follow-up (SD, 15.9 months), clinical and patient-reported outcomes were excellent. The Constant-Murley score improved a significant 29 points (P<.01). The visual analog scale pain score decreased from 55 to 5 points (P<.01), and the Dutch Simple Shoulder Test and Short Form-12 scores improved significantly (P≤.02). Five-year survival was 82.6% (95% confidence interval, 71.6%-93.6%). At 3.5-year follow-up, clinical and patient-reported outcome measures had satisfying results. [Orthopedics. 2019; 42(1):e111-e117.].

Total shoulder prosthesis with humeral resurfacing: Impact on lateral offset and short-term clinical consequences

BACKGROUND

Reports of early glenoid wear after humeral resurfacing hemiarthroplasty have prompted the use, in combination with this procedure, of newly developed glenoid implants. This combination can increase global humeral offset. The objectives of this study were to assess changes in overall lateral offset and their potential short-term clinical consequences after combined humeral resurfacing and glenoid replacement.

HYPOTHESIS

Combined humeral resurfacing and glenoid replacement induces a large increase in overall lateral offset, resulting in short-term clinical consequences.

MATERIAL AND METHODS

A single-centre prospective study was started in November 2011. Consecutive patients scheduled for total shoulder arthroplasty with humeral resurfacing were included. The primary outcome measure was the change in lateral offset between radiographs obtained pre-operatively and 3 months post-operatively. The functional outcome assessed using the Constant score was compared between the groups with a lateral offset change <10mm vs. ≥10mm.

RESULTS

From November 2011 to November 2014, 35 total shoulder arthroplasties with humeral resurfacing were performed in 32 patients with a mean age of 72.1 years (range, 55-86 years). Mean follow-up was 20±6 months (range, 12-31 months). Overall lateral offset was significantly greater post-operatively than pre-operatively (14±6mm vs. 5±7mm, p<0.0001), the mean difference being 8mm (range, 2-20mm). Post-operative range of motion was better in the group with an overall lateral offset ≥10mm (p=0.0016).

DISCUSSION

Combined humeral resurfacing and glenoid replacement markedly increases overall lateral offset. This increase is not associated with adverse effects on short-term function and may improve post-operative motion range. However, greater lateral offset elevates the loads on the glenoid implant, which may increase the risk of glenoid implant loosening and rotator cuff tearing. Close radiological monitoring is therefore imperative.

LEVEL OF EVIDENCE

IV, prospective cohort study.

Functional Outcomes of the Ream-and-Run Shoulder Arthroplasty: A Concise Follow-up of a Previous Report

We previously reported the results at an average of 4.5 years after treatment of 176 patients with the ream-and-run arthroplasty. In the present study, we present the patient self-reported functional outcomes and clinical implant survival of the original cohort at a mean of 10 years (range, 5 to 16 years). Twenty-eight (16%) of the 176 patients had a subsequent procedure, 11 (6%) died, and 30 (17%) had <5 years of follow-up. The Simple Shoulder Test (SST) score at the time of the latest follow-up was a median of 11 points (interquartile range, 9 to 12 points) and a mean (and standard deviation) of 10 ± 2.6 points, out of a possible 12 points. The present study demonstrates that the improvement in function and comfort derived from the ream-and-run procedure can be sustained at the time of mid-term follow-up.

LEVEL OF EVIDENCE

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

The accuracy and precision of radiostereometric analysis in upper limb arthroplasty

Background and purpose - Radiostereometric analysis (RSA) is an accurate method for measurement of early migration of implants. Since a relation has been shown between early migration and future loosening of total knee and hip prostheses, RSA plays an important role in the development and evaluation of prostheses. However, there have been few RSA studies of the upper limb, and the value of RSA of the upper limb is not yet clear. We therefore performed a systematic review to investigate the accuracy and precision of RSA of the upper limb. Patients and methods - PRISMA guidelines were followed and the protocol for this review was published online at PROSPERO under registration number CRD42016042014. A systematic search of the literature was performed in the databases Embase, Medline, Cochrane, Web of Science, Scopus, Cinahl, and Google Scholar on April 25, 2015 based on the keywords radiostereometric analysis, shoulder prosthesis, elbow prosthesis, wrist prosthesis, trapeziometacarpal joint prosthesis, humerus, ulna, radius, carpus. Articles concerning RSA for the analysis of early migration of prostheses of the upper limb were included. Quality assessment was performed using the MINORS score, Downs and Black checklist, and the ISO RSA Results - 23 studies were included. Precision values were in the 0.06-0.88 mm and 0.05-10.7° range for the shoulder, the 0.05-0.34 mm and 0.16-0.76° range for the elbow, and the 0.16-1.83 mm and 11-124° range for the TMC joint. Accuracy data from marker- and model-based RSA were not reported in the studies included. Interpretation - RSA is a highly precise method for measurement of early migration of orthopedic implants in the upper limb. However, the precision of rotation measurement is poor in some components. Challenges with RSA in the upper limb include the symmetrical shape of prostheses and the limited size of surrounding bone, leading to over-projection of the markers by the prosthesis. We recommend higher adherence to RSA guidelines and encourage investigators to publish long-term follow-up RSA studies.

Radiological and functional 24-month outcomes of resurfacing versus stemmed anatomic total shoulder arthroplasty

PURPOSE

This study compared clinical and radiographic outcomes of patients undergoing resurfacing total shoulder arthroplasty (TSA) with those treated with a stemmed TSA.

METHODS

Patients with primary osteoarthritis who underwent humeral resurfacing (RES) or stemmed (STA) TSA were identified in our shoulder arthroplasty register for retrospective analysis. Standard radiographs and clinical/patient-rated assessments were made up to 24 months post-surgery. Implant revisions were assessed. Patients were frequency-matched in a 1:1 (RES:STA) ratio based on gender and age, and compared with regard to operation time and shoulder function (Constant, SPADI and Quick DASH scores). Mixed models with statistical adjustments were applied.

RESULTS

From 2006 to 2014, 44 RES and 137 STA operations were performed in 157 patients; one and two revisions were recorded in the RES and STA group, respectively. The final matched cohort included a total of 69 patients and 37 operations per treatment group. Resurfacing TSA was 17 min shorter (95%CI: 5-28) compared to the stemmed procedure (p = 0.005). RES and STA patients showed significant functional improvement six months post-implantation, yet all measured scores did not differ between the groups at 2 years (p ≥ 0.131). The status of static centering of the humeral head, acromiohumeral distance, and a lack of signs of implant loosening were also similar between treatments.

CONCLUSION

Similar 24-month post-operative radiological and functional outcome is achieved by RES and STA patients, even with a shorter RES surgery time. Larger cohorts and longer follow-up are required to better assess implant survival.

Fretting and Corrosion in Modular Shoulder Arthroplasty: A Retrieval Analysis

Tribocorrosion in taper junctions of retrieved anatomic shoulder arthroplasty implants was evaluated. A comparison of the tribocorrosion between cobalt-chromium and titanium alloy stems was conducted and the observations were correlated with the individual's clinical data. Adverse effects caused by metal debris and subsequent elevated serum metal ion levels are frequently reported in total hip arthroplasty. In total shoulder arthroplasty, to date only a small number of retrieval analyses are available and even fewer address the issue of tribocorrosion at the taper junctions. A total of 36 retrieved hemiarthroplasties and total shoulder arthroplasties were assessed using the modified Goldberg score. The prevalence of fretting and corrosion was confirmed in this cohort. Titanium stems seem to be more susceptible to damage caused by tribocorrosion than cobalt-chromium stems. Furthermore, stemless designs offered less tribocorrosion at the taper junction than stemmed designs. A weak correlation between time to revision and increased levels of tribocorrosion was seen. Whether or not tribocorrosion can lead to adverse clinical reactions and causes failure of shoulder arthroplasties remains to be examined.