Stemless Total Shoulder Arthroplasty Research Articles

High revision rate of metal-backed glenoid component and impact on the overall revision rate of stemless total shoulder arthroplasty: a cohort study from the Danish Shoulder Arthroplasty Registry.

There is controversy regarding the results of stemmed and stemless total shoulder arthroplasty (TSA) used for osteoarthritis. Therefore, we aimed to compare revision rates of stemmed and stemless TSA and to examine the impact of metal-backed glenoid components. We included all patients reported to the Danish Shoulder Arthroplasty Register from January 1, 2012 to December 31, 2022 with an anatomical TSA used for osteoarthritis. Primary outcome was revision (removal or exchange of components) for any reason. 3,338 arthroplasties were included. The hazard ratio for revision of stemless TSA adjusted for age and sex was 1.83 (95% confidence interval [CI] 1.21-2.78) with stemmed TSA as reference. When excluding all arthroplasties with a metal-backed glenoid component, the adjusted hazard ratio for revision of stemless TSA was 1.37 (CI 0.85-2.20). For the Eclipse stemless TSA system, the adjusted hazard ratio for revision of a metal-backed glenoid component was 8.75 (CI 2.40-31.9) with stemless Eclipse with an all-polyethylene glenoid component as reference. We showed that the risk of revision of stemless TSAs was increased and that it was related to their combination with metal-backed glenoid components.

Use of a Krackow suture technique with PEEK barrel augmentation for subscapularis repair is stronger than use of a Mason-Allen suture technique

BackgroundIn total shoulder arthroplasty, the subscapularis tendon is routinely mobilized, by tenotomy, peel, or lesser tuberosity osteotomy, to visualize the joint and allow proper implant positioning. Careful mobilization of the subscapularis is undertaken to achieve an anatomic tension-free repair. This cadaveric study tests the biomechanical differences of 2 repair techniques of the subscapularis peel (SP) compared to the classically described technique. We hypothesize that adaptation of this SP technique using a custom-designed polyether-ether-ketone (PEEK) barrel in the bicipital groove may further stabilize suture repair of the subscapularis. MethodsTwenty paired cadaveric shoulder specimens underwent SP and repair via transosseous suture fixation. The PEEK barrel used was a laboratory prototype designed for the study (Catalyst OrthoScience, Naples, FL, USA). Five specimens were repaired using a traditional Mason-Allen suture; their paired shoulders were repaired using the PEEK barrel and a Mason-Allen suture. Five specimens were repaired using the Krackow suture; their paired shoulders were repaired using the PEEK barrel and a Krackow suture. Mechanical testing was performed using a uni-axial materials testing system with primary outcome of gap displacement and secondary outcomes of maximum load to failure and method of failure. ResultsThe Krackow repair method with and without PEEK augmentation was significantly stiffer than the Mason-Allen repair method with and without PEEK augmentation (P < .001 across all groups). Adding augmentation changed the strength of the Mason-Allen repair without achieving statistical significance (P = .0925). Intergroup differences in cyclic displacement were not statistically significant. The Krackow repair methods had higher mean maximal load at failure than the Mason-Allen repairs of 534 ± 108 N and 266 ± 98 N, respectively (P < .001). Maximum load at 5 mm displacement was significantly different across groups (P = .004). Methods of failure in the Mason-Allen technique groups included knot and tendon failure, and in the Krackow technique groups included suture failure and lesser tuberosity fracture. ConclusionRepairing the subscapularis with a Krackow suture is significantly stronger than a Mason-Allen repair in stiffness as well as load to failure. The results reported here compare a Krackow suture with a more common Mason-Allen suture configuration, and demonstrate the application of PEEK augmentation to subscapularis repair techniques. This study can guide surgeon selection of an ideal subscapularis repair technique for stemmed or stemless total shoulder arthroplasty.

MEDIUM-TERM OUTCOMES FOLLOWING STEMLESS ANATOMIC TOTAL SHOULDER ARTHROPLASTY: CLINICAL AND RADIOLOGICAL FINDINGS (MINIMUM FIVE-YEAR FOLLOW-UP)

In recent years, use of anatomic stemless total shoulder arthroplasty (AsTSA) has increased. Despite evidence to suggest good mid-term results at 2-year follow-up there is a paucity of evidence for longer term follow-up. This study aimed to investigate outcomes at a minimum of 5 years post-operatively following primary AsTSA.This study is a retrospective case series of all patients who underwent a Mathys Affinis AsTSA from July 2010 (first case) to August 2018 (to allow minimum 5-year follow-up). Clinical outcomes included revision rate, range of motion and patient reported outcomes (Oxford Shoulder Score and Numerical Satisfaction Score). Radiological outcome was assessment of radiolucent lines for Lazarus grading.A total of 105 stemless TSAs were implanted. Five patients underwent revision (4.8%). Seventy-five AsTSA's were included in the final study for analysis of 5-year outcomes. Median follow-up time was 6.1 years. Median age was 69 years old and 81% were female. Oxford shoulder score showed a range of 18 to 48, with a median score of 47. Satisfied or very Satisfied was selected in 94.37%. Median range of motion assessments showed forward elevation 160°, abduction 150°, external rotation 40°, and mode internal rotation was to the lumbar spine. No glenoid lucency was present in 79.7%. There were 9.5% with Lazarus Grade 1 lucency, 5.4% with Lazarus Grade 2, and 5.4% Lazarus Grade 3. No humeral lucency was observed.This cohort study demonstrates promising clinical and radiological outcomes for the Mathys Affinis Stemless TSA at minimum 5 years post-operatively.

Lower deltoid tuberosity indices are associated with the use of a stemmed instead of a preoperatively planned stemless implant

BackgroundAnatomic total shoulder arthroplasty (TSA) using a stemless prosthesis continues to increase in popularity as literature supporting their use grows. Intraoperative findings, however, may require switching from a planned stemless prosthesis to using a stemmed implant, yet literature attempting to understand the incidence and risk factors leading to this outcome is limited. The purpose of this study was to document the incidence of intraoperative change from a planned stemless implant to a stemmed prosthesis and to determine the correlation between the deltoid tuberosity index and this decision. MethodsAll patients scheduled to undergo TSA with a stemless humeral prosthesis between 2018 and 2023 at a single academic institution were retrospectively reviewed. Sociodemographic data, comorbidities, and preoperative deltoid tuberosity indices (DTI) were collected for review. DTI was used as an approximation for a patient’s bone mineral density. Surgeon plan for stemless TSA was verified via saved three-dimensional preoperative plans. ResultsNinety-two patients were scheduled to undergo stemless TSA, 8 (8.70%) of which received a stemmed implant based on intraoperative findings. In all cases, the operative surgeon deemed the metaphyseal bone inadequate to facilitate use of a stemless implant. DTI was significantly higher in the stemless group relative to the stemmed group (1.55 vs. 1.37, P = .0023). Discussion and ConclusionApproximately 9% of planned stemless TSA were converted to stemmed TSA due to proximal humerus bone insufficiency based on surgeon assessment at time of surgery. Diminished DTI was noted to be a risk factor. Preoperative planning may be improved by including imaging parameters to assess bone sufficiency (eg, DTI).

Stress shielding of the proximal humerus in stemless anatomic total shoulder arthroplasty

Background This study aimed to assess the radiographic proximal humerus bony adaptations to stress shielding and associated clinical outcomes following stemless total shoulder arthroplasty. Methods A retrospective review of all patients who underwent stemless total shoulder arthroplasty surgery at our centre from 2010 to 2020 was performed. Results In total, 115 stemless total shoulder arthroplasty utilising a single implant design with a minimum one-year follow-up were identified over a 10-year period. The median follow-up was 3.5 years (range: 1–8.9 years). Evidence of stress shielding was observed in 20 cases (17%), (9 mild (8%), 0 moderate (0%), 11 severe (9%). No significant differences were seen between stress shielding and gender, body mass index, post-operative range-of-motion, patient satisfaction, or Oxford shoulder score. No significant differences were seen between the operative technique and stress shielding. No cases had evidence of humeral lucency. In total, 24 cases (21%) had evidence of glenoid lucency of Lazarus grade 0–3. No cases had Lazarus grades 4 or 5. There was no association between stress shielding and humeral lucency, glenoid lucency, or revision procedure. Discussion Stress shielding in this study occurred at lower rates than anticipated following stemless total shoulder arthroplasty and was not associated with radiographic evidence of lucency, revision procedures, or adverse effect on clinical outcome measures.

Stemless total shoulder arthroplasty using a novel multiplanar osteotomy and elliptical humeral head results in both improved early range of motion and radiographic center of rotation compared with standard total shoulder arthroplasty.

Restoration of the native glenohumeral anatomy is an important consideration in obtaining optimal range of motion (ROM) after anatomic total shoulder arthroplasty (TSA). Recently, a new stemless TSA system has been developed that uses both a multiplanar osteotomy (MPO), to improve the surgeon's ability to restore humeral center of rotation (COR), and an elliptical humeral head to improve ROM. The purpose of our study was to compare the difference in early postoperative ROM and restoration of radiographic COR, between this stemless TSA and standard stemmed TSAs. This was a retrospective review of 50 consecutive primary TSAs performed by a single surgeon for glenohumeral osteoarthritis. The initial cohort underwent TSA with a standard stemmed humeral component with a circular humeral head (n=25), whereas the subsequent cohort underwent stemless TSA using an MPO and an elliptical humeral head (n=25). Postoperative data collection included active shoulder ROM as measured by goniometer, complications or revision surgery, and measurements of radiographic COR. Patients were assessed at 6 weeks, 12 weeks, 6 months, and 12 months after surgery. Change in COR was determined on postoperative radiographs by 2 fellowship-trained surgeons on 2 separate occasions. Intra- and interrater reliability were computed using intraclass correlation coefficients. For both mean forward flexion (FF) and external rotation (ER), there was greater ROM in the MPO-elliptical group at all time points, which was statistically significant. Mean change in FF favored the MPO group at 6 and 12 weeks and was statistically significant and above the minimal clinically important difference (MCID): 6 weeks, standard -15.8° vs. MPO 8.4° (P=.004); 12 weeks, standard 6.4° vs. MPO 29.2° (P=.001). Mean change in ER favored the MPO group at 6 weeks and was statistically significant: standard 5.4° vs. MPO 14.0° (P=.02). There were no revision surgeries in either group. Average change in COR was 2.7 mm in the standard group and 1.8 mm in the MPO-elliptical group, which was statistically significant (P<.001). Number of patients with >3 mm of difference in COR was 10 (40%) in the standard group and 1 (5%) in the MPO-elliptical group, which was statistically significant (P=.002). Average intraclass correlation coefficient was 0.75, indicating good reliability within and between surgeon measurements. The use of a multiplanar osteotomy and elliptical humeral head was associated with improved early range of motion and better reproduction of the radiographic COR compared with standard stemmed TSA.

Is stemless total shoulder arthroplasty indicated in elderly patients?

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). 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. 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. 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.

Short-term radiographic analysis of a stemless humeral component for anatomic total shoulder arthroplasty

Standard stemmed humeral implants have traditionally been utilized for total shoulder arthroplasty (TSA) with a recent trend to implant smaller stems including short and stemless humeral designs. However, the rate of stress shielding after stemless TSA has not been primarily studied. Therefore, the objective of this study is to report the short-term survivorship and radiographic analysis of a stemless humeral implant. A retrospective cohort review of a prospectively collected, multicenter database for patients undergoing total shoulder arthroplasty with a stemless humeral design (Equinoxe Stemless; Exactech, Inc., Gainesville, FL, USA) with a minimum of 2 years clinical and radiographic follow-up was performed. The primary outcomes were to report the location and rate of stress shielding from a radiographic analysis of the humeral stem. Additionally, the revision rate of the humeral stem is reported. The secondary outcomes included ASES scores, visual analog scale (VAS) pain scores, and range of motion (ROM). Radiographs (anterior-posterior/Grashey and axillary) were reviewed blindly by two fellowship trained shoulder surgeons. Radiographic analysis included stress shielding (partial or complete cortical resorption) and subsidence or shift in component position. Fifty four patients were included in this study with an average follow-up of 27 months (range 24-32 months). The average age of this cohort was 65 years (range 57-73 years) with 23 patients (43%) being female. Stress shielding was observed in 4 patients (7%) with the medial calcar being the most common location of stress shielding. Three of the 4 patients (75%) had evidence of partial resorption while 1 patient (25%) had evidence of complete resorption. No humeral component shift or subsidence was observed. There were no revisions due to humeral component complications. There was 1 revision surgery for aseptic glenoid loosening. A significant improvement for all clinical outcome measures was seen including with respect to VAS pain, which improved from 6.2 to 1.8 (P<.05), ASES, which improved from 38.2 to 81.8 (P<.05), and ROM which forward flexion improved from 120 degrees to 153 degrees (P<.05) and external rotation improved from 29 degrees to 49 degrees (P<.05). This ongoing study demonstrates a low rate of stress shielding for a stemless design humeral implant at short-term follow-up without any revision surgery due to humeral component complications. Longer term radiographic and clinical analysis with this cohort will be needed to confirm these findings and theoretical benefits for future revision surgeries.

Accuracy of reconstruction of proximal humerus anatomy: a comparison between stemless and stemmed shoulder modular replacement system

BackgroundThe restoration of proximal humeral anatomy in anatomic total shoulder arthroplasty (TSA) is paramount for clinical outcome and longevity of the prosthesis. The aim of our study was to determine whether there is a difference in the accuracy of restoration of proximal humeral anatomy between stemless and stemmed TSA versions of the Shoulder Modular Replacement system (Shoulder Modular System, LimaCorporate, San Daniele del Friuli, Italy). MethodsWe retrospectively reviewed all patients who received an anatomic TSA for glenohumeral osteoarthritis in North Shore Hospital, Auckland, New Zealand between 2015 and 2018. Three independent fellowship-trained shoulder surgeons compared preoperative and postoperative proximal humerus anatomy using 6 parameters measured on plain radiographs: humeral head height, humeral medial offset, humeral head centering, humeral head diameter, neck shaft angle, and lateral humeral offset. We assessed the accuracy of restoration of proximal humerus anatomy with the anatomic reconstruction index (ARI), a scoring scale that ranges 0-10, a higher score indicating a more accurate reconstruction. ResultsWe investigated a total of 63 shoulders, 43 (68%) in female patients and 20 (32%) in male patients, average age at surgery 70 years (range 44-86 years). No statistically significant differences were found in the 6 radiographic parameters measured postoperatively between groups. The average ARI was 7.29 in the stemless and 7.41 in the stemmed group (P = .742). The average ARI corresponded with a good reconstruction in both stemmed and stemless TSA. No statistically significant difference was observed in the distribution of very good/excellent, good, and poor reconstruction categories between groups (P = .660). ConclusionWe concluded that there is no significant difference in the accuracy of restoration of proximal humerus anatomy between stemless and stemmed TSA. The results indicate that both stemmed and stemless TSA can reproduce the proximal humerus anatomy with good radiographic results.

Mid-Term to Long-Term Follow-Up of Stemless Anatomic Total Shoulder Arthroplasty.

The purpose was to report mid-term to long-term clinical outcomes in a multicentre series of patients who received stemless total shoulder arthroplasty (TSA). The hypothesis was that stemless TSA would be a safe and effective treatment with satisfactory clinical outcomes. Authors retrospectively reviewed records of 62 stemless TSAs implanted between March 2013 and December 2014. Six were excluded because they had fractures or muscular impairment, which left 56: primary osteoarthritis (n = 49), rheumatoid arthritis (n = 4), avascular necrosis (n = 1), or glenoid dysplasia (n = 2). Outcomes were absolute Constant Score (CS), age-/sex-adjusted CS, and the American Shoulder and Elbow Surgeons (ASES) score. Proportions of patients that achieved substantial clinical benefits for absolute CS and ASES scores were determined. Of the 56 patients, 8 (14%) died (unrelated to TSA), 5 (9%) were lost to follow-up, and 2 (4%) refused participation. One patient was reoperated for infection with implant removal (excluded from analysis), and one for periprosthetic fracture without implant removal. At 7.6 ± 0.5 years (range 6.8-9.3), the remaining 40 patients, aged 71.0 ± 8.5 years, achieved net improvements of 40.7 ± 15.8 (CS), 62%±23% (age-/sex-adjusted CS), and 59.7 ± 16.4 (ASES). Of patients with complete absolute CS (n = 37) and ASES score (n = 28), respectively, 33 (89%) and 27 (96%) achieved substantial clinical benefits. Stemless TSA yields improvements in functional outcomes at mid-term to long-term that exceed the substantial clinical benefits of the absolute CS and ASES score at a mean follow-up of 7.6 years. Although the findings of this study revealed low complications and revision rates, more studies are needed to confirm long-term benefits of stemless TSA. IV, case series.

Outcomes Between Stemmed and Stemless Total Shoulder Arthroplasty: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Both stemmed and stemless designs for total shoulder arthroplasty (TSA) have demonstrated efficacious outcomes for the surgical treatment of primary glenohumeral joint osteoarthritis. The purpose of this systematic review and meta-analysis was to compare the clinical outcomes of stemmed versus stemless TSA in randomized controlled trials. We hypothesized that there would be no differences in Constant Score (CS), range of motion, or adverse events, such as periprosthetic fracture and/or revision surgery. Using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a systematic review of the literature was done using MEDLINE, SPORTDiscus, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Registry of Controlled Trials, Embase, and Web of Science databases. Outcomes of interest included CS, range of motion, and adverse events (periprosthetic fracture and revision). Summary effect estimates of the mean difference between stemmed and stemless TSA for each outcome were estimated in random effects models. The search yielded 301 articles with 4 appropriate for qualitative analysis, including the results of 229 stemmed and 358 stemless TSAs. No significant difference was observed in postoperative CS (P = 0.36), forward flexion (P = 0.93), abduction (P = 0.30), or external rotation (P = 0.34) between stemmed and stemless TSA. No significant difference was observed in change in CS (P = 0.27), forward flexion (P = 0.25), or external rotation (P = 0.74). A change in abduction was significantly different between stemmed and stemless TSA (standardized mean difference = -0.64; 95% confidence interval, -1.20 to -0.08) in favor of stemmed TSA (P = 0.02), attributed to preoperative differences. No significant difference was observed in periprosthetic fractures (P = 0.07) or revision (P = 0.90). TSA with stemless versus stemmed humeral components was not associated with notable differences in functional and clinical outcomes. No difference was observed between stemmed and stemless designs in postoperative forward flexion, abduction, or external rotation. Similarly, there was no difference in change in forward flexion or external rotation. A markedly greater improvement in abduction was observed with stemmed TSA, likely due to the lower preoperative motion in the stemmed cohort in one of the studies. No differences were observed between stemmed and stemless designs in the rate of humeral fracture or risk of revision. Level II; systematic review and meta-analysis of prospective randomized controlled trials.

Concordance of Preoperative 3D Templating in Stemless Anatomic Total Shoulder Arthroplasty.

Recent advances in preoperative 3D templating software allow surgeons to plan implant size and position for stemless total shoulder arthroplasty (TSA). Whether these preoperative plans accurately reflect intraoperative decisions is yet unknown, and the purpose of this study was to evaluate concordance between planned and actual implant sizes in a series of patients undergoing stemless TSA. A retrospective cohort of consecutive, anatomic, stemless TSA cases performed by two surgeons between September 2019 and February 2021 was examined. Preoperative templated plans were collected using 3D planning software, and the sizes of planned glenoid, humeral head, and nucleus "stem" implants and other procedural data were recorded, along with sociodemographic information. These predicted parameters were compared with the implant sizes, and the concordance of these templated plans was quantified by direct comparison and bootstrapped simulations. Fifty cases met inclusion criteria, among which perfect concordance across all three implants was observed in 11 cases (22%). The glenoid implant had the highest concordance (80%) relative to the humeral head and nucleus implants (38% and 60%, respectively), which was statistically significant ( P < 0.001). Planned humeral head implants were more often oversized relative to their actual implanted size. However, 84% of the planned humeral heads were within 1 diameter size; in addition, 98% of the planned glenoid implants were within one size and all were within 10 mm of the implanted glenoid backside radius. All nucleus implants were within one size. Final implant sizes demonstrated variable concordance relative to preoperative plans, with glenoid implants having the highest accuracy and humeral heads having the highest variability. Multiple factors contributed to the varying concordances for the different implants, suggesting possible areas of improvement in this technology. These results may have implications for logistics, intraoperative efficiency, and overall cost and underscore the potential value of this technology. Level III.

High prevalence of early stress shielding in stemless shoulder arthroplasty

IntroductionThe rates of early stress shielding in stemless total shoulder arthroplasty (TSA) in current literature are very low and inconsistent with our observations. We hypothesized that the incidence of early stress shielding in stemless TSA would be higher than previously reported. MethodsAll stemless TSA in a prospective database using a single humeral implant comprised the study cohort of 104 patients, of which 76.0% (79 patients) had a minimum one year radiographic and clinical follow-up. Radiographs were reviewed for humeral stress shielding, humeral radiolucent lines, and humeral or glenoid loosening/migration. Stress shielding and radiolucent lines were classified by location. Demographics and clinical outcomes, including American Shoulder and Elbow Surgeons (ASES) score and visual analog scale (VAS) pain score, were compared between patient cohorts with and without stress shielding. ResultsAt one year, 41.8% of patients had humeral stress shielding. Medial calcar osteolysis was seen in 32.9% of all patients and 78.8% of the stress shielding cohort. There were no cases of radiolucent lines or humeral or glenoid loosening/migration. There was no significant difference in age between cohorts (P = .308), but there were significantly more females (P = .034) and lower body mass index in the stress shielding cohort (P = .004). There were no significant differences in preoperative ASES (P = .246) or VAS scores (P = .402) or postoperative ASES (P = .324) or VAS scores (P = .323). ConclusionStress shielding in stemless TSA is more prevalent than previously published, largely due to infrequently reported medial calcar osteolysis. Stress shielding is more common in women and patients with lower body mass index. At early follow-up there were no significantly worse outcomes in the stress shielding cohort, but longer-term follow-up is needed to fully understand the impact of stress shielding on function and stability.

Short-term results of a new anatomic stemless shoulder arthroplasty - A prospective multicentre study.

Anatomic total shoulder arthroplasty (TSA) has been continuously developed and current designs include stemless or canal-sparing humeral components. In the literature stemless and canal sparing TSA showed good clinical and radiographic results, which were comparable to stemmed TSA. The aim of this study was to determine the short-term clinical and radiological outcomes of a new stemless TSA design. A prospective multicentre study including 154 total shoulder arthroplasty patients with a follow up of 12 months was performed. At the time of follow up 129 patients were available for review. The adjusted Constant Murley score,1 Oxford Shoulder Score, EQ-5D-5L score and radiographs were examined preoperatively, 3 and 12 months after the implantation of the new stemless TSA implant GLOBAL ICON™ (DePuy Synthes, Warsaw, IN, USA). Complications were documented. Implant Kaplan-Meier survivorship was 98.7% at 12 months. From baseline to 12 months follow-up, all scores showed a progressive significant mean improvement. The mean adjusted Constant score increased from 42.3 to 96.1 points (p<0.001). The Oxford Shoulder Score showed an increase of 21.6 points (p<0.001). The postoperative radiographs showed no continuous radiolucent lines, subsidence, aseptic loosening or progressive radiolucency, but one osteolytic lesion was observed. Only 2 prostheses were revised. The new GLOBAL ICON stemless TSA showed good clinical and radiographic results at short-term follow up which were comparable to early results of other stemless TSA. Further studies with longer follow up are needed in the future.

Axillary nerve proximity to the humeral guide pin during stemless total shoulder arthroplasty

BackgroundThe proximity of the axillary nerve to the humeral head guide pin has not been described in current literature. Therefore, we aimed to elucidate the anatomical relationship through a cadaveric study. MethodsTen fresh-frozen cadaveric specimen were included in this study. The standard deltopectoral approach was utilized for appropriate exposure. The subscapularis and the long head of the biceps tendon were tenotomized to access the glenohumeral joint. Humeral head cut was then visually performed with humeral sizing and positioning. A Steinmann Pin was placed and advanced into the lateral cortex. Following dissection and visualization, the distance from the axillary nerve to the point of lateral humeral cortex was measured. ResultsOn average, the axillary nerve was found 7.2 ± 3.1 mm from the tip of the Steinmann Pin at the level of the lateral humeral cortex and distal to the site of cortical penetration. DiscussionSurgeons should be aware of the relationship between the axillary nerve and the humeral guide pin, and care should be taken to protect the axillary nerve during piercing of the lateral humeral cortex during pin placement. This relationship continues to be of importance, even with evolving stemless implant systems in total shoulder arthroplasty.

Short-term survival and patient-reported outcome of total stemless shoulder arthroplasty for osteoarthritis are similar to that of stemmed total shoulder arthroplasty: a study from the Danish Shoulder Arthroplasty Registry

BackgroundThe use of stemless total shoulder arthroplasty (TSA) for osteoarthritis increases, but there is a paucity on its safety and efficacy and how it performs in comparison with stemmed TSA. The aim was to compare the 5-year cumulative survival rate and patient-reported outcome after stemless and stemmed TSA for osteoarthritis.MethodsWe included all stemmed (n = 1197) and stemless (n = 253) TSA for osteoarthritis reported to the Danish shoulder arthroplasty registry from January 1, 2014, to December 31, 2018.ResultsSix (2.4%) stemless and 24 (2%) stemmed TSA were revised. The 5-year cumulative implant survival rates were 0.96 for stemless TSA and 0.97 for stemmed TSA. In the multivariate Cox regression model, the hazard ratio for revision was 1.1 (95% confidence interval, 0.5-2.6) for stemless TSA compared with stemmed TSA. The mean Western Ontario Osteoarthritis of the Shoulder (WOOS) index was 82 (standard deviation = 21) for stemmed and 86 (standard deviation = 19) for stemless TSA. The stemless TSA had a statistically significant better WOOS compared with stemmed TSA, but the difference of 6.2 (95% confidence interval, 1.4-10.4) was not regarded as clinically relevant. There was no difference in WOOS between the Nano and the Eclipse systems.DiscussionWe found a good 5-year cumulative implant survival rate of stemless TSA, which was comparable with stemmed TSA. Although the stemless TSA had a statistically significant better patient-reported outcome compared with stemmed TSA, the difference was not clinically relevant. Sparing the humeral shaft canal for later revision could be an argument for using stemless TSA instead of stemmed TSA.

Surgical time and outcomes of stemmed versus stemless total shoulder arthroplasty.

Stemless total shoulder arthroplasty (TSA) was approved for use in the United States in 2015, and there remains a paucity of data on its performance in this market. Decreased operative time without compromise of clinical outcomes is a theoretical advantage of stemless TSA, but no studies have evaluated this in a comparative study to date. Herein, the operative times and clinical outcomes of stemless vs. conventional stemmed TSA are investigated. This is a retrospective cohort study, evaluating all consecutive TSAs performed by a single surgeon between 2015 and 2018. Data were collected from 59 patients who underwent TSA with conventional, stemmed humeral implants and 115 patients in whom a stemless humeral implant was used. Operative times and demographic data were collected retrospectively from the anesthesia record, and prospectively collected patient-reported outcome measures were collected from the Surgical Outcomes System database. For patient-reported outcome measure, visual analog scale, American Shoulder and Elbow Surgeons, and Single Assessment Numerical Evaluation scores were recorded serially until a minimum 2-year follow-up. The average operative time was 24 minutes less in the stemless cohort compared with the stemmed cohort (104 minutes vs. 128 minutes, P<.001). Cost analysis showed a decreased personnel cost of 15.9% that correlates to a 3.1% overall reduction in operating room-associated cost. Patient-reported outcome scores significantly improved postoperatively in both cohorts across all time points. There was no difference found in visual analog scale, American Shoulder and Elbow Surgeons, and Single Assessment Numerical Evaluation scores between the cohorts at the 2-year follow-up. Stemless TSA significantly reduces operative time with equivalent functional outcomes at a minimum 2-year follow-up.

Food and Drug Administration–reported complications of anatomic stemless total shoulder arthroplasty vary with implant model

BackgroundStemless shoulder arthroplasty not only allows for shorter operative time and less blood loss but also for placement of the humeral head independent of the diaphysis, thereby preserving bone that may be needed for further revisions. The purpose of this study was to evaluate the current adverse event profile for anatomic stemless shoulder arthroplasty using the Manufacturer and User Facility Device database. MethodsThe adverse event reports mandated by the US Food and Drug Administration for all hospitals housed in the Manufacturer and User Facility Device database were screened for mention of anatomic stemless total shoulder arthroplasty (TSA). Each applicable report was then characterized by implant design and failure mode. ResultsThe most commonly reported stemless implants were the Zimmer Biomet Sidus, Zimmer Biomet Nano, and Arthrex Eclipse. The most common complications were pain/stiffness (16.8%), glenoid component loosening (12%), glenoid component failure (11%), and problems with attachment onto the humeral insert (9.9%). ConclusionsBecause of the benefits of increased bone preservation with less operative time and decreased blood loss compared with anatomic stemmed TSA, stemless implants are becoming increasingly popular in clinical practice. There were no findings that discourage the use of stemless TSA in the right candidate. Level of evidenceLevel III; Database Case Series Treatment Study

A biomechanical comparison of subscapularis tenotomy repair techniques for stemless shoulder arthroplasty.

One of the leading challenges for surgeons shifting to stemless anatomic total shoulder arthroplasty (TSA) is subscapularis repair. In the available literature reporting outcomes after stemless TSA, subscapularis tenotomy with side-to-side repair is the most common technique despite some concerns regarding this technique in the biomechanical and clinical literature. Accordingly, this study investigated subscapularis tenotomy repair with stemless TSA with 2 primary objectives: (1) to evaluate the subscapularis tendon dimensions with reference to subscapularis tenotomy to determine the amount of tendon remaining for side-to-side repair after shoulder arthroplasty and (2) to biomechanically compare 2 methods of subscapularis tenotomy repair after stemless TSA-side-to-side repair and anchor-based repair. We used 12 male shoulder specimens for this study. To address our first objective, measurements were made to calculate the dimensions of the subscapularis tendon at the superior, middle, and inferior levels to determine the amount of tendon remaining after tenotomy. These specimens were then divided into 2 groups (n = 6 in each group) to biomechanically compare subscapularis tenotomy repair with (1) traditional side-to-side repair and (2) anchor-based repair. The shoulders then underwent biomechanical testing with primary outcomes including load to failure and cyclic displacement. The mean subscapularis tendon width measured from the medial insertion at the lesser tuberosity to the muscle-tendon junction varied depending on the level: 19.5 mm superiorly (95% confidence interval [CI], 16.2-22.8 mm); 18.3 mm at the midportion (95% CI, 13.6-23.0 mm); and 13.1 mm inferiorly (95% CI, 9.1-17.1 mm). With a tenotomy made 1 cm medial to the lesser tuberosity insertion, a mean of 3.1 mm of tendon remained medially at the inferior subscapularis, with one-third of specimens having no tendon left medially at this level. On comparison of tenotomy repair techniques, the anchor-based technique had a 57% higher ultimate load to failure compared with the side-to-side repair (448 N vs. 249 N, P < .001). There were no significant differences in cyclic displacement (6.1 mm vs. 7.1 mm, P = .751) and construct stiffness (38.1 N/mm vs. 42.9 N/mm, P = .461) between techniques. With traditional techniques for subscapularis tenotomy for anatomic TSA, there is very little tendon remaining inferiorly for side-to-side repair. When subscapularis tenotomy is performed for stemless TSA, a double-row anchor-based repair has a better time-zero ultimate load to failure compared with side-to-side repair.

Restoration of the joint geometry after stemless shoulder arthroplasty.

This study aims to evaluate restoration of anatomy following Total Shoulder Arthroplasty (TSA) with the Mathys Affinis Short prosthesis. Over the last decade stemless shoulder arthroplasty has increased in popularity. One of the reported advantages of the stemless designs is the ability to restore anatomy following surgery. However, very few studies have evaluated restoration of anatomy following stemless shoulder arthroplasty. The study included all patients who had undergone TSA using the Affinis Short (Mathys Ltd, Bettlach, Switzerland) prosthesis for primary osteoarthritis between 2010 and 2016. The mean follow up was 42.8 months (range 9.4 to 83.4 months). Pre and post-operative radiographs were assessed for Centre of Rotation (COR), Humeral Head Height (HHH), Humeral Head Diameter (HHD), Humeral Height (HH) and, Neck Shaft Angle (NSA) using the best fit circle method on PACS software. Measurements were scored and compared to assess the accuracy of the implant in restoring the native geometry, including the intraobserver variability. The same data was collected by another experienced observer to measure the interobserver variability. The deviation of COR of the prosthesis from the anatomical centre was less than 3 mm in 58 cases (85%). Humeral head height and humeral head diameter showed a variation of less than 3 mm in 66 cases (97%) and 43 cases (63%) respectively. Humeral height followed a similar trend, with 62 cases (91.2%) showing a difference of less than 5 mm. The neck shaft angle showed a variation of more than 8 degrees in 38 cases (55%), and 29 cases (42.6%) had a postoperative angle of less than 130 degrees. Overall, stemless total shoulder arthroplasty with the Affinis Short prosthesis allows excellent restoration of anatomy confirmed by most of the measured radiographic parameters. The variability in neck shaft angle might be due to differing surgical techniques, with some surgeons preferring a slightly vertical neck cut to protect the rotator cuff insertion.