Survival of stemless humeral head replacement in anatomic shoulder arthroplasty: a prospective study

Two-year follow-up of the SMR stemless platform shoulder system: a multicenter, prospective clinical study

Background

The use of stemless shoulder arthroplasty for osteoarthritis has grown substantially over the past decades. The goal of this study is to evaluate the clinical and radiological outcomes of the Lima SMR stemless anatomic and reverse total shoulder arthroplasty.

Methods

Seventy-three implants in 73 patients (61 anatomic total shoulder arthroplasties [aTSAs] and 12 reverse shoulder arthroplasties [RSAs]) were analyzed with a minimum follow-up of 2 years. The average age in the aTSA group was 65.8 ± 8.7 and 78.3 ± 4.8 in the RSA group. Primary osteoarthritis was the indication in most cases (aTSA 93.7%, RSA 67%). Patients were evaluated preoperatively, at 4, 12, and 24 months postoperatively using the Constant score, the ASES, Oxford Shoulder Score, EuroQol 5 Dimensions 5 Levels questionnaire, range of motion scores, and radiographically. Statistical significance was evaluated using the paired t-test (P < .5).

Results

At 2-year follow-up, the overall average Constant score significantly improved from 40.0 ± 16.7 to 80.9 ± 21.4 (P < .001). Improvement of the ASES (from 31.7 ± 15.6 to 82.5 ± 19.4) and Oxford Shoulder Score (from 19.1 ± 7.4 to 41.9 ± 7.9) was also significant (P < .001). In the aTSA group, all range of motion scores improved significantly (P < .001). In the RSA group, all range of motion scores improved but only active forward flexion and external rotation in abduction improved significantly (P < .05). Most patients were satisfied or completely satisfied at 24 months (aTSA 93.9%, RSA 100%). Two humeral implants in the RSA configuration showed loosening on the first postoperative day related to excessive forces exerted on the shoulder, both requiring revision to a stemmed implant. In the aTSA group, no signs of radiolucencies, osteolysis, gradual loosening, or migration of the components were seen at the final follow-up. In the RSA group, one case had radiolucent lines with subsidence of the humeral core at 12 months, which had not progressed at 24 months and was asymptomatic. All other RSA cases showed no radiolucent lines, migration, scapular notching, or osteolysis. Three anatomic implants were converted with retention of the glenoid baseplate and humeral core to a reverse arthroplasty due to atraumatic cuff failure (N = 2) and traumatic cuff failure (N = 1). After these procedures, patients were satisfied with their results. There were no other complications.

Conclusion

The 2-year results presented in this study show good functional and radiological outcomes using the SMR stemless system.

Evolution of Stemless Reverse Shoulder Arthroplasty: Current Indications, Outcomes, and Future Prospects

Reverse total shoulder arthroplasty (rTSA) is increasingly being used as a reliable option for various shoulder disorders with deteriorated rotator cuff and glenohumeral joints. The stemless humerus component for shoulder arthroplasties is evolving with theoretical advantages, such as preservation of the humeral bone stock and decreased risk of periprosthetic fractures, as well as clinical research demonstrating less intraoperative blood loss, reduced surgical time, a lower rate of intraoperative fractures, and improved center of rotation restoration. In particular, for anatomical total shoulder arthroplasty (aTSA), the utilization of stemless humeral implants is gaining consensus in younger patients. The current systematic review of 14 clinical studies (637 shoulders) demonstrated the clinical outcomes of stemless rTSA. Regarding shoulder function, the mean Constant-Murley Score (CS) improved from 28.3 preoperatively to 62.8 postoperatively. The pooled overall complication and revision rates were 14.3% and 6.3%, respectively. In addition, recent studies have shown satisfactory outcomes with stemless rTSA relative to stemmed rTSA. Therefore, shoulder surgeons may consider adopting stemless rTSA, especially in patients with sufficient bone quality. However, further long-term studies comparing survivorship between stemless and stemmed rTSA are required to determine the gold standard for selecting stemless rTSA.

High Complication and Revision Rates in Anatomical Total Shoulder Arthroplasty with the Combination of Polyethylene and Cementless Convertible Metal-Backed Glenoid Components: A Retrospective Cohort Study

Background

Historically, Metal-Backed (MB) glenoid components in anatomical total Shoulder arthroplasty (aTSA) are prone to failure primarily due to loosening between the metal and bony surface. However, newer generations of MB glenoid components have performed well in reverse shoulder arthroplasty (RSA), with convertibility being considered to be the most significant benefit of MB components. Theoretically, MB components may be a viable option in "Rotator cuff at risk" cases. The aim of this study is to compare revisions versus revision-free survivorship and highlight problems associated with using convertible MB glenoid components in aTSA.

Methods

Between December 2015 and September 2018, aTSA was performed on 30 patients utilizing 32 implants with convertible MB glenoid (two patients were operated bilaterally). The first investigation was performed at a mean of 55.9 months (43-76) by search in the national registry for revisions with twelve cases. The second FU on all remaining patients without revisions was conducted at a mean of 54.9 months (46-71) through physical examination with fourteen patients (sixteen implants), with four patients missing. Demographic data, indications, complications, revisions, and re-operations were recorded for each patient.

Results

High rates of complications led to revisions or re-operation in aTSA in combination with MB (15/32). Seven problems were associated with polyethylene (PE), which included loosening, disengagement, or wear. Eight complications were not directly associated with the MB component. There was one with loosening on the metal-bone interface side. Conversion to RSA was possible in three cases, and secondary cuff failure was seen once. High infection rates (2/32) led to a different strategy for antibiotics and preoperative preparations.

Conclusion

MB glenoid components caused unacceptably high complication and revision rates in aTSA. PE wear, disengagement, or loosening were the main reasons for revisions. Therefore, procedures with MB glenoid components were abandoned in aTSA.

Level of Evidence

Level IV case series, treatment study.

Stemless anatomic total shoulder arthroplasty is associated with less early postoperative pain

Background

Improvements in pain control after shoulder arthroplasty with a reduction in narcotic use continues to be an important postoperative goal. With the increased utilization of stemless anatomic total shoulder arthroplasty (aTSA), it is relevant to compare between stemmed and stemless arthroplasty to assess if there is any association between this implant design change and early postoperative pain.

Methods

Patients from a multicenter, prospectively-maintained database who had undergone a stemless aTSA with a minimum of two year clinical follow-up were retrospectively identified. Patients who underwent aTSA with a short stem were identified in the same registry, and matched to the stemless aTSA patients by age, sex and preoperative pain score. The primary study outcome was the Visual Analog Scale pain score. Secondary pain outcomes were the American Shoulder and Elbow Surgeons shoulder pain subscore, Western Ontario Osteoarthritis of the Shoulder physical symptoms subscore, and the Single Assessment Numeric Evaluation score. Finally, the percentage of patients who could sleep on the affected shoulder was assessed for each group. These pain-related clinical outcomes were assessed and compared preoperatively, and postoperatively at 9 weeks, 26 weeks, one year and two years. For all statistical comparisons, P > .05 was considered significant.

Results

124 patients were included in the study; 62 in each group. At 9 weeks after surgery, statistically significantly improved pain control was reported by patients undergoing stemless aTSA, as assessed by the Visual Analog Scale (stemless: 1.5, stemmed: 2.5, P = .001), American Shoulder and Elbow Surgeons pain subscore (stemless: 42.4, stemmed: 37.3, P < .001), Western Ontario Osteoarthritis of the Shoulder Physical Symptoms (stemless: 80.3, stemmed: 73.1, P = .006) and Single Assessment Numeric Evaluation (stemless: 58.1, stemmed: 47.4, P = .011). Patients who underwent a stemless aTSA were significantly more likely to be able to sleep on the affected shoulder at 9 weeks (29% vs. 11%, odds ratio 3.2, 95% confidence interval 1.2-8.4, P = .014). By 26 weeks postoperatively, there were no differences in all pain-specific outcomes. At two years postoperatively, patient-reported outcomes, range of motion, and strength measures were all similar between the two cohorts.

Conclusion

Stemless aTSA provides earlier improvement in postoperative shoulder pain compared to matched patients undergoing short-stem aTSA. Additionally, earlier return to sleeping on the affected shoulder was reported in the stemless aTSA group. The majority of these differences dissipate by 26 weeks postoperatively and there were no differences in pain, patient-reported outcomes, range of motion or strength measures between stemless and short-stem aTSA at 2 years postoperatively.

Primary Total Shoulder Arthroplasty is Superior to Hemiarthroplasty for the Treatment of Glenohumeral Arthritis: Analysis of 5-year Outcomes in a Large Surgical Database

Background

Total shoulder arthroplasty (TSA) is the preferred treatment for glenohumeral arthritis refractory to nonoperative measures. However, some surgeons have argued for a role for hemiarthroplasty (HA) in the setting of a smooth glenoid that articulates appropriately with the humeral head. The purpose of this study is to evaluate long-term revision rates and short-term postoperative complications in patients undergoing either HA or TSA for glenohumeral arthritis.

Methods

A retrospective review of patients who underwent HA and TSA was conducted using a commercially available national database. Demographics, postoperative complications, risk factors, revision rates, and costs were analyzed using 2 sample t-tests, chi-squared tests, and multivariate logistic regressions.

Results

Patients were stratified by operation: (1) HA (n = 1615) or 2) TSA (n = 7845). Patients undergoing primary TSA had higher rates of prior ipsilateral rotator cuff repair and corticosteroid injections. At 2 years, patients who underwent HA, 3.0% of patients had revision surgery, compared to 1.6% of patients who underwent TSA (P = .002); at 5 years, 3.7% of the HA cohort (P < .0001) had revision surgery, compared to 1.9% of patients who underwent TSA.

Conclusions

Patients undergoing TSA or RTSA for glenohumeral arthritis had higher preoperative co-morbidities but had no difference in short-term complication rates with a lower risk of revision surgery at both 2-year and 5-year follow-up when compared to HA. Increasing age, female sex, hyperlipidemia, postoperative infection, shoulder instability, and thromboembolism all independently increased odds for revision shoulder arthroplasty for glenohumeral arthritis.

Level of evidence Level

III.

Anatomic glenohumeral arthroplasty: State of the art

Anatomical total shoulder arthroplasty in its modern form where it reproduces the normal shoulder has been utilized clinically for more than half a century. As the technology and the designs have changed to recreate the humeral and glenoid sides of the joint, the sophistication of design has resulted in the growing number of cases annually worldwide. This increase is due in part to the increasing number of indications that the prosthesis can treat with successful results. On the humeral side, there have been design changes to better reflect the proximal humeral anatomy, and humeral stems are increasingly placed safely without cement. Platform systems which allow conversion of a failed arthroplasty to a reverse configuration without stem extraction is another design change. Similarly, there has been increasing utilization of short stem and stemless humeral components. Extensive experience with shorter stem and stemless devices, however, has yet to demonstrate the purported advantages of these devices, as recent studies have demonstrated equivalent blood loss, fracture rates, operative times, and outcome scores. Easier revision with these shorter stems remains to be definitively established, with only one study comparing the ease of revision between stem types. On the glenoid side, hybrid cementless glenoids, inlay glenoids, cementless all-polyethylene glenoids, and augmented glenoids have all been investigated; however, the indications for these devices remain unclear. Lastly, innovative surgical approaches to implanting shoulder arthroplasty and the use of patient specific guides and computerized planning, while interesting concepts, still await validation before they are utilized on a widespread basis. While reverse shoulder arthroplasty has been increasingly used to reconstruct the arthritic shoulder, anatomic glenohumeral replacement maintains a significant role in the armamentarium of the shoulder surgeon.

Bone quality in total shoulder arthroplasty: a prospective study correlating computed tomography Hounsfield units with thumb test and fracture risk assessment tool score

Background

To evaluate if Hounsfield units (HU) measured on preoperative computed tomography (CT) scans at the anatomic neck of the proximal humerus correlates with intraoperative findings of the "thumb test" in assessment of bone quality in shoulder arthroplasty patients.

Methods

Primary anatomic total shoulder and reverse total shoulder arthroplasty patients from 2019-2022 with an available preoperative CT scan of the operative shoulder were prospectively enrolled at a single center with 3 surgeons who perform shoulder arthroplasty. The "thumb test" was performed intraoperatively; a positive test signified "good bone." Demographic information, including prior dual x-ray absorptiometry scans, was extracted from the medical record. HU at the cut surface of the proximal humerus were calculated, as was cortical bone thickness on preoperative CT. Fracture risk assessment tool (FRAX) scores were calculated for 10-year risk of osteoporotic fracture.

Results

A total of 149 patients were enrolled. Mean age was 67.6 ± 8.5 years with 69 (46.3%) being males. Patients with a negative thumb test were significantly older (72.3 ± 6.6 vs. 66.5 ± 8.6 years; P < .001) than those with a positive thumb test. Males were more likely to have a positive thumb test than females (P = .014). Patients with a negative thumb test had significantly lower HUs on preoperative CT (16.3 ± 29.7 vs. 51.9 ± 35.2; P < .001). Patients with a negative thumb test had a higher mean FRAX score (14.1 ± 7.9 vs. 8.0 ± 4.8; P < .001). Receiver operator curve analysis was performed to identify a cut-off value for CT HU of 36.67, above which the thumb test is likely to be positive. Furthermore, receiver operator curve analysis also identified optimal cut-off values for 10-year risk of fracture by FRAX score of 7.75 HU, below which the thumb test is likely to be positive. Fifty patients were at high risk based on FRAX and HU; surgeons classified 21 (42%) as having "poor bone" quality through a negative thumb test. High-risk patients had a negative thumb test 33.8% (23/68) and 37.1% (26/71) of the time for HU and FRAX, respectively.

Conclusions

Surgeons are poor at identifying suboptimal bone quality at the anatomic neck of the proximal humerus based on intraoperative thumb test when referencing against CT HU and FRAX scores. The objective measures of CT HU and FRAX scoring may be useful metrics to incorporate into surgeons' preoperative plans for humeral stem fixation using readily available imaging and demographic data.

Arthroscopic Removal of the Polyethylene Glenoid Component After Total Shoulder Arthroplasty: A Systematic Review

Purpose

To identify prior studies of arthroscopic glenoid component removal after total shoulder arthroplasty (TSA) and understand indications, techniques and patient outcomes.

Methods

A search of the English language literature on arthroscopic removal of the glenoid component (ARGC) after TSA published between 2005 and 2021 was performed from MEDLINE and EMBASE databases. Articles with ARGC after TSA were identified and we recorded article characteristics as well as patient demographics and outcomes contained within the studies.

Results

A total of six publications (two case reports and four retrospective case series) detailing the outcome of ARGC performed on twenty-five shoulders were identified. The average time from index procedure to glenoid removal was 117 months and mean age at time of ARGC was 75 years. Although patient reported outcomes measures (PROMs) varied in type and reporting style, all articles reported improvements in PROMs. Twenty patients in this systematic review were evaluated for post-operative complications and the complication rate was found to be 15% (n = 3). There were 2 cases (18%) of superior migration of the humeral head relative to the glenoid and no reported cases of anterior or posterior humeral head subluxation. Two of 25 patients (8%) underwent subsequent open revision procedures.

Conclusions

The limited number of publications in this systematic review demonstrates that ARGC after TSA can result in improvements in both pain and PROMs. This less-invasive arthroscopic technique may be an alternative to open revision for lower demand patients; however, future prospective, comparative studies are necessary to better define indications.

Stemless anatomic total shoulder arthroplasty: surgical technique and review of the literature

Stemless anatomic total shoulder arthroplasty (aTSA) is a promising option for the treatment of degenerative disease in patients. This novel technique avoids the stem-related complications associated with the traditional stemmed aTSA. Stemless aTSA offers additional benefits such as decreased operative time, preservation of bone stock, improved radiographic outcomes, and easier revision. Moreover, loading of the metaphyseal region rather than the diaphysial region with traditional stemmed implants can decrease stress shielding. When compared to stemmed-implants, stemless aTSA has demonstrated similar outcomes and complication rates. The purpose of this article is to analyze published outcomes and complications following the utilization of stemless aTSA. Additionally, key aspects of the surgical technique that may promote optimal results in stemless aTSA implantation are presented.

Survivorship of Anatomic Total Shoulder Arthroplasty

Anatomic total shoulder arthroplasty provides pain relief and improved quality of life for patients suffering from glenohumeral arthritis. The 10-year survival rate for these implants has been most recently reported at 96%. As the number of shoulder arthroplasties per year increases, it is important to evaluate factors associated with failure. Patient-specific variables such as age, sex, medical comorbidities, a history of previous shoulder surgery, and rotator cuff integrity can influence implant survival. Both surgeon and hospital volume have been shown to affect perioperative outcomes. Implant design and glenoid pathoanatomy are important structural considerations because both have a causal relationship with survivorship. Modifiable factors, such as smoking, body mass index, and alcohol or opioid consumption, should be addressed preoperatively when possible. Modifiable factors that pertain to surgery are equally as important; it is the responsibility of the surgeon to be aware of the reported outcomes for varying implants and technique-related pearls and pitfalls. For those perioperative factors that are nonmodifiable, it is prudent to counsel patients accordingly because these individuals may be more likely to require an eventual revision procedure.

Subscapularis Repair Prior to Subscapularis Takedown in Anatomic Shoulder Arthroplasty: Improving Anatomic Restoration and Mechanics of the Subscapularis

Traditionally, total shoulder arthroplasty is performed using a deltopectoral approach through which the glenohumeral joint is accessed by mobilization of the subscapularis. Despite several variations on the subscapularis management techniques, postoperative complications, including subscapularis deficiency and lower functional outcomes, remain an area for improvement. The purpose of this Technical Note is to describe in detail our technique for management of the subscapularis in the setting of a stemless humeral implant through which the repair is planned and almost entirely performed at the beginning of the case, prior to the subscapularis peel. This technique aims to improve outcomes after total shoulder arthroplasty by 1) avoiding the anatomic implant with anchor drilling, 2) improving procedure efficiency, and 3) anatomically "repairing" the subscapularis prior to takedown by placing anchors exactly at the repair-tension site.

Determining the ideal osteotomy for stemless total shoulder replacement: a cadaveric study

HYPOTHESIS

We sought to determine the angle of osteotomy that produces a circular humeral cut surface.

METHODS

A total of 49 cadaveric shoulders, from 25 cadavers, underwent sequential humeral head osteotomy from 180° (vertical, in line with the humeral diaphyseal shaft), in 10° increments, until the rotator cuff insertion was encountered. At each stage, the anteroposterior (AP) and superoinferior (SI) distances were recorded. The data were analyzed for normality and then assessed to determine the optimum cut angle.

RESULTS

The AP/SI ratio is an indication of roundness. Plotting values of 1 - AP/SI (ie, error) vs. cut angle allowed us to plot the likelihood of producing a circular cut surface using a third-order curve that created the best fit to the data set (R² = 0.99). The results from this study suggest that the optimum osteotomy angle that produces a circular cut surface is 23° from the vertical. The cohort data illustrated that at this angle, the average roundness error was 1% with a 95% confidence limit of <1%. There was no significant difference (P > .05) between sexes.

CONCLUSION

The humeral head shape changes from oval to circular and then to an oval cut surface as the osteotomy angle increases from the vertical toward the horizontal. The range of angles within which the cut surface is circular, within a 10% error margin, is 18°-27° from the vertical, which is much less than the traditional osteotomy angle of 45°.

Early fixation of the humeral component in stemless total shoulder arthroplasty : a radiostereometric and clinical study with 24-month follow-up

AIMS

Stemless humeral implants have been developed to overcome stem-related complications in total shoulder arthroplasty (TSA). However, stemless implant designs may hypothetically result in less stable initial fixation, potentially affecting long-term survival. The aim of this study is to investigate early fixation and migration patterns of the stemless humeral component of the Simpliciti Shoulder System and to evaluate clinical outcomes.

METHODS

In this prospective cohort study, radiostereometric analysis (RSA) radiographs were obtained in 24 patients at one day, six weeks, six months, one year, and two years postoperatively. Migration was calculated using model-based RSA. Clinical outcomes were evaluated using the visual analogue scale (VAS), the Oxford Shoulder Score (OSS), the Constant-Murley Score (CMS), and the Disabilities of the Arm, Shoulder and Hand (DASH) score.

RESULTS

At two years, median translation along the x-, y-, and z-axis was -0.12 mm (interquartile range (IQR) -0.18 to 0.02), -0.17 mm (IQR -0.27 to -0.09), and 0.09 mm (IQR 0.02 to 0.31). Median rotation around the x-, y-, and z-axis was 0.12° (IQR -0.50 to 0.57), -0.98° (IQR -1.83 to 1.23), and 0.09° (IQR -0.76 to 0.30). Overall, 20 prostheses stabilized within 12 months postoperatively. Four prostheses showed continuous migration between 12 and 24 months. At two-year follow-up, with the exception of one revised prosthesis, all clinical scores improved significantly (median VAS difference at rest: -3.0 (IQR -1.5 to -6.0); OSS 22.0 (IQR 15.0 to 25.0); CMS 29.5 (IQR 15.0 to 35.75); and DASH -30.0 (IQR -20.6 to -41.67) (all p < 0.001)) with the exception of one revised prosthesis.

CONCLUSION

In conclusion, we found that 20 out of 24 implants stabilized within 12 months postoperatively. The significance of continuous migration in four implants is unclear and future research on the predictive value of early migration for future loosening in TSA is required. Clinical results revealed a clinically relevant improvement. Cite this article: Bone Joint J 2022;104-B(1):76-82.

Anatomic Total Shoulder Arthroplasty versus Hemiarthroplasty for Glenohumeral Osteoarthritis: A Systematic Review and Meta-Analysis

Purpose: Both anatomic total shoulder arthroplasty (TSA) and shoulder hemiarthroplasty (SHA) are used for the management of end-stage glenohumeral osteoarthritis (GHOA). The present study compared TSA and SHA in terms of clinical outcome and complication rate. Methods: This meta-analysis followed the PRISMA guidelines. In October 2021, the following databases were accessed: Web of Science, Google Scholar, Pubmed, Scopus. All clinical trials comparing anatomical TSA versus SHA for GHOA were considered. Results: Data from 11,027 procedures were retrieved. The mean length of the follow-up was 81.8 (16 to 223.20) months. The mean age of the patients was 61.4 ± 8.6 years, and 56.0% (5731 of 10,228 patients) were women. At last follow-up, the age-adjusted constant score was greater following TSA (p < 0.0001), as were active elevation (p < 0.0001), flexion (p < 0.0001), abduction (p < 0.0001), and American Shoulder and Elbow Surgeons Shoulder Score (p < 0.0001). Postoperative pain (p < 0.0001) and revision rate (p = 0.02) were lower in the TSA group. Conclusions: Anatomic TSA performed better than SHA in patients with GHOA.

Revision of a Stemless Anatomic Implant into a Stemless Reverse Implant

INTRODUCTION

Stemless anatomic implants are the growing standard for solving osteoarthritis of the shoulder. If there are secondary rotator cuff insufficiency and the need to revise the implant into a reverse total shoulder, there is usually the option to revise it into a stemmed implant with losing the benefits of stemless implants. There are only a few stemless reverse implants available on the market. Usually, they are recommended as primary implants, but not for revision surgery. Case Report. A 61-year-old male with an indwelling anatomic stemless TESS (Total Evolutive Shoulder System, Zimmer Biomet, Warsaw, USA) implant presented in our clinic with growing pain and loss of range of motion. The TESS was implanted in 2007 as a hemishoulder arthroplasty. The X-ray was showing a stable implanted corolla with clearly growing protrusion of the glenoid. Because of the clinical presentation and the ultrasound investigation that showed only remnants of the supraspinatus and infraspinatus left, we decided that it is necessary to revise the stable implant in a reverse total shoulder arthroplasty. As the TESS was not designed to be convertible, it was clear that it has to be explanted. Due to the young age of the patient, we proposed an "off-label" change to a stemless reverse implant, e.g., the LIMA SMR stemless reverse prosthesis. A revision was possible without much bone loss, so the stemless reverse implant could be used. The clinical and radiological 2-year follow-up showed a good result.

CONCLUSION

Stemless implants are well known for anatomic implants, rarely for reverse implants, and seldom used for revision into reverse stemless. This case report shows that it is possible to revise a stemless anatomic implant with a stemless reverse, as long as the rules for implantation are applicable.