Clinical and radiologic results after anatomic stemless shoulder prosthesis: a minimum 4-year follow-up

Clinical results and computed tomography analysis of intuitive shoulder arthroplasty (ISA) stemless at a minimum follow-up of 2 years

BACKGROUND

The utilization of stemless anatomic total shoulder arthroplasty is on the rise. Epiphyseal fixation leads to radiological bone remodeling, which has been reported to exceed 40% in certain studies series. The aim of this study was to present the clinical and radiological outcomes of a stemless implant with asymmetric central epiphyseal fixation at an average follow-up of 31 months.

MATERIALS AND METHODS

This retrospective multicenter study examined prospective data of patients undergoing total anatomic arthroplasty with intuitive shoulder arthroplasty Stemless implant and followed up at least 2 years. Clinical assessment included preoperative and final follow-up measurements of active range of motion, Constant score, and Subjective Shoulder Value. Anatomical epiphyseal reconstruction and bone remodeling at the 2-year follow-up were assessed by standardized computed tomography scanner (CT scan). Statistical analysis employed unpaired Student's t-test or chi-squared test depending on the variable type, conducted using EasyMedStat software (version 3.22; www.easymedstat.com).

RESULTS

Fifty patients (mean age 68 years, 62% females) were enrolled, with an average follow-up of 31 months (24-44). Primary osteoarthritis (68%) with type A glenoid (78%) was the prevailing indication. The mean Constant score and Subjective Shoulder Value improved significantly from 38 ± 11 to 76 ± 11 (P < .001) and from 31% ± 16 to 88% ± 15 (P < .001) respectively at the last follow-up. Forward elevation, external rotation, and internal rotation range of motion increased by 39° ± 42, 28° ± 21 and 3,2 ± 2,5 points respectively, surpassing the Minimally Clinically Important Difference after total shoulder arthroplasty. No revisions were necessary. CT scans identified 30% osteolysis in the posterior-medial calcar region, devoid of clinical repercussions. No risk factors were associated with bone osteolysis.

CONCLUSIONS

At an average follow-up of 31 months, intuitive shoulder arthroplasty Stemless implant provided favorable clinical results. CT analysis revealed osteolysis-like remodeling in the posterior-medial zone of the calcar (30%), without decline in clinical outcomes and revisions. Long-term follow-up studies are mandated to evaluate whether osteolysis is associated with negative consequences.

A comparison of revision rates for stemmed and stemless primary anatomic shoulder arthroplasty with all-polyethylene glenoid components: analysis from the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND

We compared the rate of all-cause revision of 2 classes of primary anatomic shoulder arthroplasty, stemmed (stTSA) and stemless (slTSA), undertaken with cemented all-polyethylene glenoid components.

METHODS

A large national arthroplasty registry identified 2 cohort groups for comparison, stTSA and l undertaken for all diagnoses between January 1, 2011, and December 31, 2021. A subanalysis from January 1, 2017, allowed capturing of additional patient demographics including American Society of Anesthesiologists score, body mass index, and glenoid morphology. The cumulative percent revision (CPR) was determined using Kaplan-Meier estimates of survivorship and hazard ratios (HR) from Cox proportional hazard models adjusted for age and gender.

RESULTS

Of the 7995 stTSA procedures, the CPR at 9 years was 5.6% (95% confidence interval [CI]: 5.0, 6.4), and for 3156 slTSA procedures, the CPR was 4.4% (95% CI: 3.6, 5.5). There was no significant difference in the rate of revision between the study groups (HR = 0.76 [95% CI: 0.51, 1.14], P = .189, adjusted for age, gender, humeral head size, humeral fixation, bearing surface, glenoid design, and mean surgeon volume [MSV]). There was an increased rate of revision for stTSA and slTSA undertaken with humeral head sizes <44 mm (stTSA <44 mm vs. 44-50 mm, HR = 1.56 [CI: 1.18, 2.08], P = .001; slTSA <44 mm vs. 44-50 mm, HR = 2.08 [CI: 1.32, 3.33], P = .001). MSV as a continuous predictor was not a revision risk to stTSA vs. slTSA, but categorically, a low MSV (<10 stTSA + slTSA cases per annum) was associated with a higher revision rate for stTSA (10-20 cases/yr vs. <10 cases/yr, HR = 0.72 [CI: 0.55, 0.95], P = .019) but was not in slTSA. Revision rates were increased for stTSA with non-crosslinked polyethylene (XLPE) glenoids vs. XPLE after 2 years (HR = 2.20 [CI: 1.57, 3.08], P < .001) but did not significantly differ for slTSA. Metal/XPLE (humeral/glenoid) bearing surface of stTSA rate of revision was not different from each combination of slTSA bearing surface. Instability/dislocation was a revision risk for slTSA vs. stTSA (HR = 1.93 [CI: 1.28, 2.91], P = .001), but from 2017, neither of American Society of Anesthesiologists score, body mass index, and glenoid morphology changed the rate of revision.

CONCLUSIONS

Revision rates of stTSA and slTSA did not significantly differ and were associated with humeral head size but not patient characteristics. Surgeon inexperience of anatomic shoulder arthroplasty and non-XLPE glenoids were risk factors for stTSA revision but not slTSA. The metal/XLPE stTSA rate of revision was not found to differ significantly from slTSA regardless of polyethylene or humeral head bearing type. Revision for instability/dislocation was more common for slTSA.

Medium-Term Clinical Outcomes of the Global Icon Stemless Shoulder System: Results of a 2-Year Follow-Up

The primary aim of this study was to assess the medium-term outcomes of the Global Icon stemless shoulder replacement in patients who have undergone primary total shoulder arthroplasty (TSA) for glenohumeral joint osteoarthritis. A retrospective review of patients who had undergone a TSA using the Global Icon stemless shoulder system was performed. The Western Ontario Osteoarthritis Shoulder (WOOS) Index and Oxford Shoulder Score (OSS) were evaluated pre-operatively and at 12 to 24 months post-operatively. Radiological outcomes, operation time, and post-operative complications were reported. Primary analysis for the WOOS Index and OSS focused on detecting within-group treatment effects at 24 months using a repeated measures ANOVA. Thirty patients were included in the study. Post-surgery, there was a significant improvement at 24 months on the OSS (ES = 0.932, CI: 41.7 to 47.7, p < 0.001) and the WOOS Index (ES = 0.906, CI: 71.9 to 99.8, p < 0.001). Radiographs revealed that no component loosened, migrated, or subsided. The median operative time was 75.5 (IQR: 12.25, range: 18 to 105) min. No implant-related complications were reported. The Global Icon stemless replacements have excellent clinical outcomes in this cohort at 12- and 24-month follow-up with no implant-related complications.

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.

Is stemless total shoulder arthroplasty indicated in elderly patients?

BACKGROUND AND HYPOTHESIS

Stemmed anatomic total shoulder arthroplasty has represented the gold standard for the treatment of glenohumeral osteoarthritis with an intact rotator cuff for decades. To the author's knowledge, no study has specifically examined the outcomes of stemless, modular total shoulder arthroplasty in elderly patients. The hypothesis of this study was that stemless anatomic total shoulder arthroplasty in elderly patients (age ≥70 years) would have equivalent clinical and radiographic outcomes compared with a younger population (age <70 years).

MATERIALS AND METHODS

A prospectively collected database of patients undergoing primary, modular, stemless anatomic total shoulder arthroplasty for osteoarthritis was retrospectively reviewed. Patient-determined outcomes including the Western Ontario Osteoarthritis Index (WOOS) score, American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numeric Evaluation (SANE) score, Simple Shoulder Test score, and Shoulder Activity Level score were recorded preoperatively and postoperatively at 1 year and 2 years. Preoperative and 1-year postoperative range of motion was recorded. Postoperative radiographs were examined to assess for radiographic evidence of complications.

RESULTS

Stemless arthroplasty was planned in 116 patients. Seven patients underwent conversion intraoperatively to a stemmed prosthesis. There was no difference between patients aged <70 yr and those aged ≥70 years who required intraoperative deviation from the preoperative plan to a stemmed prosthesis (5.8% vs 6.4%, P = .90). At the time of stemless arthroplasty, 64 patients were aged <70 yr and 44 patients were aged ≥70 years. Between the 2 groups, there were no clinically or statistically significant differences in WOOS, ASES, and SANE scores at baseline, 1-year follow-up, or 2-year follow-up. The changes in all scores from baseline to 2 years were similar between the group aged <70 yr and the group aged ≥70 years. There was no difference in the percentage of patients achieving the minimal clinically important difference or substantial clinical benefit in either group after shoulder arthroplasty at 2-year follow-up. There was no difference between the 2 groups in terms of final postoperative range of motion or change in range of motion for any metric examined. There was no evidence of radiographic complications in either group.

CONCLUSIONS

Age ≥70 years does not appear to be a contraindication to stemless anatomic total shoulder arthroplasty. Postoperative improvements in patient-determined outcome scores, the percentage of patients achieving clinically important outcomes for the ASES, SANE, and WOOS scores, and postoperative range of motion were similar between patients aged <70 yr and those aged ≥70 years. There was no difference between the groups regarding the patients who required intraoperative deviation from the preoperatively planned stemless prosthesis to a stemmed prosthesis. Neither age group demonstrated a radiographically apparent complication.