Glenoid baseplate migration with subsequent stabilization after reverse shoulder arthroplasty using a through-growth cage: a matched cohort study

BackgroundFew studies have evaluated the outcomes of glenoid baseplate migration after reverse shoulder arthroplasty (RSA). The question is whether an ingrowth central cage implant that has undergone early migration can restabilize due to cage ingrowth. The primary purpose of this study is to evaluate the radiographic factors associated with glenoid baseplate migration after RSA using a through-growth cage implant and secondarily evaluate their clinical outcomes with nonoperative management.MethodsA retrospective review of a single institution database was performed from January 1,2008 to June 30, 2017 for all shoulders using a single implant system (Equinoxe, Exactech, Inc., Gainesville, FL, USA). All RSAs with a documented complication of glenoid loosening were evaluated. Chart and radiograph review was performed to identify shoulders with confirmed glenoid loosening undergoing revision (revision group, n = 10) and those with migration that stabilized over time and avoided revision surgery (stable migration group, n = 10). The stable migration group was matched to an age-, sex-, and follow-up matched control group (1:3) (control group, n = 30). Demographic factors, preoperative and immediate postoperative radiographic factors, active range of motion (ROM), and patient-reported outcomes (PROMs) were compared. Radiographic factors evaluated included preoperative alpha/beta angles, humeral lengthening, glenosphere overhang, prosthesis-scapular neck angle, glenosphere inclination, and postoperative alpha/beta angles.ResultsA total of 50 RSA patients were evaluated at a mean follow-up of 38 months. Immediate postoperative inferior glenoid overhang was significantly less in the stable migration group compared to the control group (6.2 vs. 8.6 mm, P = .03). Preoperative ROM and PROMs were similar amongst all 3 groups. The stable migration group demonstrated improved ROM and PROMs compared preoperatively with all ROM and PROM values exceeding the minimally clinically important difference (MCID). The control group demonstrated greater improvements in ROM and PROMs compared to the stable migration group, with a majority exceeding the MCID. When compared to the revision group, the stable migration group had significantly greater improvements in forward flexion, ASES score, and Constant score as well as improvements above the MCID in abduction, external rotation, and SST score.ConclusionRSA patients with glenoid migration and secondary stabilization still achieve improved ROM above the MCID, but the results are inferior to those RSA patients without glenoid migration. Approximately half of the shoulders with baseplate loosening using a through-growth cage implant will restabilize and have better ROM and function compared to those that are ultimately revised.Level of EvidenceLevel III; Treatment Study     

Factors affecting internal rotation after reverse shoulder arthroplasty

BackgroundThe limitation or loss of internal rotation (IR) after the surgery is a major problem in reverse shoulder arthroplasty (RSA). The particular factors associated with postoperative IR remain unclear. We aimed to analyze the predictors of IR after RSA.MethodsWe included primary RSA patients with the following implants and a minimum of 1-year follow-up: Wright Aequalis (n = 25), DJO Encore (n = 29), Biomet Comprehensive (n = 40), and Exactech Equinoxe (n = 29). Age, sex, dominant hand, primary diagnosis, implant type, preoperative critical shoulder angle, pre- and postoperative acromiohumeral distance, lateral offset of implant, glenosphere inclination, peg-glenoid rim distance (PGRD), glenosphere overhang, scapular notching, subscapularis (SSc) repair, pre- and postoperative ROM, and functional scores were assessed. IR was assessed using a 10-point scale based on the following anatomical levels: from the greater trochanter to the buttocks (2 points), from the sacrum to L4 (4 points), from L3 to L1 (6 points), from T12 to T8 (8 points), and from T7 to T1 (10 points). Univariable and multivariable analyses were performed to identify the factors affecting the IR after RSA.ResultsOne hundred twenty-three shoulders (123 patients) with a mean follow-up of 30.59 ± 19.55 (range, 12–83) months were evaluated. In the univariable analysis, preoperative diagnosis [odds ratio (OR) = 0.243, P = 0.001], implant type (P = 0.002), PGRD (OR = 1.187, P = 0.003), and preoperative IR (P < 0.001) were found to be factors associated with postoperative IR. Preoperative IR was the only factor associated with postoperative IR in the multivariable analysis (P < 0.001). Patients with preoperative IR scores of 10 or 8 points showed significantly better IR after RSA than those with preoperative IR scores of 2 or 4 points (10 points vs. 2 or 4 points; OR = 15.433, P = 0.002, 8 points vs. 2 or 4 points; OR = 6.078, P < 0.001).ConclusionPreoperative IR was the only independent factor for IR after RSA. Patients with excellent preoperative IR had better postoperative IR than those with poor preoperative IR. Preoperative diagnosis, implant type, SSc repair, implant lateralization, glenosphere inferior placement, and scapular notching were not identified as independent predictors of IR after RSA in our sample size.     

Clinical and radiographic results of eccentric glenoid reaming in reverse total shoulder arthroplasty

BackgroundOne option for treating glenoid bone loss in reverse shoulder arthroplasty (RSA) is eccentric reaming of the glenoid, but the effect on clinical results is unclear. The aim of this study was to investigate the association between medialization of the bone-baseplate interface (herein, ‘medialization’) caused by eccentric reaming of the glenoid and scapular notching, baseplate loosening, and clinical outcomes after RSA.MethodsWe retrospectively reviewed data for 91 patients who underwent primary RSA between January 2014 and December 2016 with a lateralized implant and a minimum 2-year follow-up. The amount of medialization was estimated using a 3-dimensional computed tomography scan-based computer planning software. The average amount of medialization estimated by the 3-dimensional planning software was 3.4 mm (range, 0.5-10 mm). Outcomes included range of motion (ROM), American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST) score, visual analog scale (VAS) for pain, and the rates of scapular notching and baseplate loosening. The association between the estimated medialization and the outcomes of interest was evaluated using multivariate models.ResultsAfter controlling for age, sex, diagnosis, subscapularis repair, glenosphere size, and baseline ROM, medialization was not associated with the postoperative abduction (P = .35), external rotation (ER) at 90° (P = .16), internal rotation at 90° (P = .08), and internal rotation at the back (P = .06). However, we found a significant association between medialization and postoperative ER at the side (P = .02). According to the multivariate model, for a 1-mm increase in medialization during surgery, a decrease of 1.6° in postoperative ER would be expected. We found no association between medialization and the postoperative ASES score (P = .48), SST score (P = .59), or VAS score (P = .27). At a minimum of 2 years of follow-up, we found no baseplate loosening or radiographic signs of baseplate loosening in any patient. Scapular notching of grades 1 to 2 was observed in 22 patients (24%). We were not able to detect a difference in scapular notching when medialization was > 1 mm ver when medialization ≤ 1 mm (odds ratio, 2.5; 95% confidence interval: 0.28-23).ConclusionsIncreasing medialization due to eccentric reaming after RSA with a lateralized implant was associated with a decrease in postoperative ER at the side. However, increasing medialization was not associated with worse patient-reported outcome scores or increased baseplate loosening at short-term follow-up.     

Use of machine learning to assess the predictive value of 3 commonly used clinical measures to quantify outcomes after total shoulder arthroplasty

BackgroundAn important psychometric parameter of validity that is rarely assessed is predictive value. In this study we utilize machine learning to analyze the predictive value of 3 commonly used clinical measures to assess 2-year outcomes after total shoulder arthroplasty (TSA).MethodsXGBoost was used to analyze data from 2790 TSA patients and create predictive algorithms for the American Shoulder and Elbow Surgeons (ASES), Constant, and the University of California Los Angeles (UCLA) scores and also quantify the most meaningful predictive features utilized by these measures and for all questions comprising each measure to rank and compare their value to predict 2-year outcomes after TSA.ResultsOur results demonstrate that the ASES, Constant, and UCLA measures rarely considered the most-predictive features relevant to 2-year TSA outcomes and that each outcome measure was composed of questions with different distributions of predictive value. Specifically, the questions composing the UCLA score were of greater predictive value than the Constant questions, and the questions composing the Constant score were of greater predictive value than the ASES questions. We also found the preoperative Shoulder Pain and Disability Index (SPADI) score to be of greater predictive value than the preoperative ASES, Constant, and UCLA scores. Finally, we identified the types of preoperative input questions that were most-predictive (subjective self-assessments of pain and objective measurements of active range of motion and strength) and also those that were least-predictive of 2-year TSA outcomes (subjective task-specific activities of daily living questions).DiscussionMachine learning can quantify the predictive value of the ASES, Constant, and UCLA scores after TSA. Future work should utilize this and related techniques to construct a more efficient and effective clinical outcome measure that incorporates subjective and objective input questions to better account for the preoperative factors that influence postoperative outcomes after TSA.Level of EvidenceLevel III; Retrospective Comparative Study     

The effect of humeral stem alignment in reverse shoulder arthroplasty

BackgroundThe impact of stem alignment on hip arthroplasty outcomes has been thoroughly evaluated, but there is limited data assessing this relationship in reverse shoulder arthroplasty (RSA). In this study, we investigated the association of humeral stem alignment with patient outcomes following RSA.MethodsUsing our prospectively maintained institutional registry, we identified patients who underwent reverse shoulder arthroplasty between July 2015 and September 2017 with minimum 2-year follow-up. Two raters independently assessed stem alignment using full-length humeral view radiographs. Stem alignment was correlated to American Shoulder and Elbow Surgeons (ASES) score, Visual Analog Scale (VAS) pain score, range of motion, complications, and scapular notching at 2-year follow-up.ResultsOf the 117 patients that fit our inclusion criteria, 68 (58%) had neutral or valgus alignment and 49 (42%) had varus alignment. ASES score, VAS pain score, range of motion, complications, and scapular notching showed no differences between the 2 cohorts at 2-years postoperatively. Change (mean, SD) in ASES scores (52.5 ± 17.7 vs. 41.3 ± 21.2, P = .01) and VAS pain scores (−5.7 ± 2.5 vs. −4.6 ± 2.6, P = .02) were greater in the neutral/valgus cohort compared to the varus cohort. Demographics analysis revealed that the neutral or valgus cohort had a larger female population (74% vs. 59%, P < .01) while men were more likely to be in the varus cohort.ConclusionHumeral stem alignment does not appear to affect clinical outcomes at 2-years postoperatively. Improvement in ASES score and VAS pain score were slightly inferior in varus patients, however this difference was not clinically relevant. There may be a correlation between male gender and varus alignment, likely due to better bone quality and larger musculature. Further investigation into the association between stem angulation and clinical outcomes is warranted.Levels of EvidenceLevel III; Retrospective Cohort Study.     

Adjusting Implant Size and Position Can Improve Internal Rotation After Reverse Total Shoulder Arthroplasty in a Three-dimensional Computational Model

BackgroundEfforts during reverse total shoulder arthroplasty (RSA) have typically focused on maximizing ROM in elevation and external rotation and avoiding scapular notching. Improving internal rotation (IR) is often overlooked, despite its importance for functional outcomes in terms of patient self-care and hygiene. Although determinants of IR are multifactorial, it is unable to surpass limits of bony impingement of the implant. Identifying implant configurations that can reduce bony impingement in a computer model will help surgeons during preoperative planning and also direct implant design and clinical research going forward.Questions/purposesIn a CT-modeling study, we asked: What reverse total shoulder arthroplasty implant position improves the range of impingement free internal rotation without compromising other motions (external rotation and extension)?MethodsCT images stored in a deidentified teaching database from 25 consecutive patients with Walch A1 glenoids underwent three-dimensional templating for RSA. Each template used the same implant and configuration, which consisted of an onlay humeral design and a 36-mm standard glenosphere. The resulting constructs were virtually taken through ROM until bony impingement was found. Variations were made in the RSA parameters of baseplate lateralization, glenosphere size, glenosphere overhang, humeral version, and humeral neck-shaft angle. Simulated ROM was repeated after each parameter was changed individually and then again after combining multiple changes into a single configuration. The impingement-free IR was calculated and compared between groups. We also evaluated the effect on other ROM including external rotation and extension to ensure that configurations with improvements in IR were not associated with losses in other areas.ResultsCombining lateralization, inferiorization, varus neck-shaft angle, increased glenosphere size, and increased humeral anteversion resulted in a greater improvement in internal rotation than any single parameter change did (median baseline IR: 85° [interquartile range 73° to 90°]; combined changes: 119° [IQR 113° to 121°], median difference: 37° [IQR 32° to 43°]; p < 0.001).ConclusionIncreased glenosphere overhang, varus neck-shaft angle, and humeral anteversion improved internal rotation in a computational model, while glenoid lateralization alone did not. Combining these techniques led to the greatest improvement in IR.Clinical RelevanceThis computer model study showed that various implant changes including inferiorization, varus neck-shaft angle, increased glenosphere size, and increased humeral anteversion can be combined to increase impingement-free IR. Surgeons can employ these currently available implant configurations to improve IR when planning and performing RSA. These findings support the need for further clinical studies validating the effect of implant configuration on resultant IR.     

Is there a threshold of preoperative function that predicts failure to achieve clinically significant outcomes after total and reverse shoulder arthroplasty?

BackgroundThe purpose of this study was to determine if there is a threshold of preoperative function that is predictive of postoperative outcomes and the likelihood of achieving clinically significant outcomes following shoulder arthroplasty (SA).MethodsWe retrospectively identified patients who underwent a primary SA at our institution. Patients with preoperative and postoperative American Shoulder and Elbow Surgeons scores (ASES) were included in our analysis. A receiver operating characteristic (ROC) analysis was utilized to reach a preoperative ASES threshold correlated with achievement of the following clinically significant outcomes: minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptom state. This analysis was performed for our entire SA cohort and subanalyzed for total shoulder arthroplasty (TSA) and reverse shoulder arthroplasty (RSA). Fischer exact tests were used to analyze categorical data while continuous data were analyzed using t-tests. For the ROC, area under the curve (AUC) was calculated, along with bootstrap 95% confidence intervals and P values, with <0.05 as significant.ResultsA total of 516 patients were included (164 TSA and 352 RSA). ROC analysis yielded a preoperative ASES above 54 as predictive of failure to achieve MCID for all SAs (AUC, 0.77; P < .001), above 49 for TSA (AUC 0.74, P < .001), and above 56 for RSA (AUC 0.79, P < .001). Patients with preoperative ASES scores above 54 were significantly less likely to achieve MCID (odds ratio 5.1, P < .001) and SCB (odds ratio 7.2, P < .001); however, they had higher postoperative ASES scores (84 vs. 78, P < .001). A preoperative ASES score of 73 corresponded to a 50% chance of achieving MCID. ROC analysis also yielded a preoperative ASES score above 51 as predictive of failure to achieve SCB for all SA, TSA, and RSA (AUC: 0.79, 0.78, and 0.80, respectively, all P < .001). A preop ASES score of 52 corresponded to a 50% chance of achieving SCB.ConclusionPreoperative ASES scores above 49-56 are predictive of failure to achieve MCID and SCB following TSA and RSA. Although patients above these preoperative thresholds achieve higher absolute ASES scores at the final follow-up, they experienced less relative improvement from baseline. This will help surgeons counsel individual patients about appropriate expectations after arthroplasty.     

Inclination correction is associated with improved clinical outcomes in anatomic total shoulder arthroplasty

BackgroundWhile retroversion of the glenoid in anatomic total shoulder arthroplasty (TSA) has been increasingly studied, the effect of glenoid inclination on clinical outcomes has received less attention. The goal of this study was to examine the influence of pre- and postoperative inclination on clinical outcomes after anatomic TSA.MethodsPatients undergoing primary anatomic TSA with minimum 2-year outcomes were included from a multicenter prospectively maintained database of shoulder arthroplasties from 2015 to 2017. Preoperative and postoperative radiographs were independently evaluated to assess native glenoid inclination and postoperative prosthetic glenoid inclination using the previously described TSA angle. A receiver-operator characteristic (ROC) curve analysis was performed to determine if a significant threshold existed for preoperative inclination, postoperative inclination, or amount of inclination correction. A linear regression analysis assessing the correlation between each of these measurements and the postoperative Constant score was performed. For final analysis, means and standard deviations of the Constant scores for patients above and below the calculated inclination thresholds for each group were compared using SPSS.ResultsSeventy-two anatomic TSAs with minimum 2-year follow-up were included. ROC analysis determined a significant threshold of 10 degrees of postoperative inclination for prediction of the 2 year postoperative Constant score (AUC = 0.682), P= .010. This finding was additionally supported in the linear regression analysis, where postoperative inclination was significantly associated with the postoperative Constant score (P= .046). Patients below the postoperative inclination threshold of 10 degrees had significantly improved Constant scores compared to those above the threshold (mean 65.3, P= .005; Table 2). Two degrees of inclination correction was predictive of the 2 year postoperative Constant score (AUC = 0.754; P< .001; sensitivity 68%, specificity 74%). Inclination correction was significantly associated with postoperative Constant score (P= 0.003). Patients above the inclination correction threshold of 2 degrees had significantly improved Constant scores (mean 75.4) compared to those below the threshold (mean 65.9, P= .003).ConclusionsWhen appropriately corrected, preoperative inclination over 10 degrees does not appear to significantly influence postoperative outcome of anatomic TSA. There is a significant association between postoperative inclination and 2 year Constant scores. Inclination correction is particularly associated with postoperative Constant score. These results encourage the need for future studies with detailed analysis as to how to best predict and correct inclination to produce favorable and durable outcomes after anatomic TSA.Level of EvidenceLevel III; Retrospective Comparative Study     

Primary reverse shoulder arthroplasty did not result in increased blood metal ion levels regardless of glenosphere size: A randomized controlled trial

BackgroundThe utilization of reverse shoulder arthroplasty (RSA) has increased over time. Toxic increases of metal ion levels have been reported selectively after hip arthroplasty. However, studies evaluating the effect of RSA on in vivo metal ion levels have not been evaluated. Therefore, the purposes of this study were (1) to determine in vivo levels of cobalt, chromium, and nickel in a randomized controlled trial of patients undergoing reverse total shoulder arthroplasty (RSA) with one of four glenosphere sizes, and (2) to identify possible factors affecting changes in metal ion levels.MethodsBetween May 2016 and September 2018, 72 shoulders with cuff tear arthropathy, massive irreparable cuff tears, or glenohumeral osteoarthritis with posterior subluxation were randomized to undergo RSA using a single implant system and four possible glenosphere options based on size (36 or 40 mm) and offset (+2 mm, +6 mm). In vivo metal ion levels (cobalt, chromium, nickel) and complete blood count (CBC) were assessed preoperatively, 3-months, and 1-year after surgery. Clinical evaluation included pain, motion, Subjective Shoulder Value, ASES scores, and Oxford Shoulder Scores.ResultsReverse shoulder arthroplasty led to statistically significant improvements in all outcome measures considered (p < 0.001). Changes in nickel, cobalt or chromium blood levels did not reach statistical significance at 3 months (p = 0.87, 0.86, 0.85, respectively) or 1 year (p = 0.88, 0.38, 0.98, respectively). There was no difference in any of these metal ion levels when assessed by (1) glenosphere size, or (2) offset at 3 months or 1 year. This was also true when each of the four groups were assessed individually at 3 months and 1 year.ConclusionIn this randomized controlled trial of patients undergoing reverse total shoulder arthroplasty with a single design, in vivo levels of cobalt, chromium, and nickel remained reassuringly low. In addition, increase in glenosphere size, offset, or both, did not appear to affect in vivo metal ion levels over the short-term. Longer term studies are needed to further assess the effects of implant modularity on metal ion levels and their potential adverse effects in patients undergoing reverse shoulder arthroplasty.Level of evidenceLevel I; Randomized Controlled Trial     

Effect of reverse total shoulder arthroplasty humeral inclination on glenohumeral range of motion,deltoid force,and glenoid strain: a biomechanical study

BackgroundReverse total shoulder arthroplasty (RSA) primarily varies between 2 implant design options: a 135 humeral stem inclination that closely resembles anatomic orientation, versus the Grammont-style 155 humeral stem inclination that further medializes and distalizes the center of rotation (COR). The purpose of this study was to compare deltoid force, glenoid strain, and simulated glenohumeral range of motion (ROM) between RSA 135 and RSA 155 designs, with a series of standardized permutations of glenosphere offset and rotator cuff pathology.MethodsTwelve fresh-frozen cadaveric shoulder specimens were studied using a shoulder simulator. Native shoulder motion profiles for reproducible abduction range of motion were established using a customized testing device. Optical 3-dimensional tracking and pressure sensors were used to accurately record glenohumeral range of motion (ROM), deltoid force, and glenoid strain for RSA 135 and RSA 155 designs. For each cohort, all combinations of glenosphere offsets and rotator cuff tendon involvement were evaluated.ResultsThere was no significant difference in the overall abduction ROM between the 155 and the 135 humeral stem implants (P = .75). Resting abduction angle and maximum abduction angle were significantly greater with a 155 + STD (standard offset) construct than with a 135 + STD construct (P < .001 and P = .01, respectively). Both stem inclinations decreased combined deltoid force requirements as compared the native shoulder with a massive cuff tear. Effective glenoid strain did not vary significantly between 135 + STD and 155 + STD constructs (P = .66).ConclusionOverall, range of motion between the 135 and the 155 humeral stem inclinations was not significantly different. The cumulative deltoid force was lower in RSA shoulders when compared to native shoulders with massive rotator cuff tears, highlighting the utility of both implant designs. The Grammont-style 155 stem coupled with a 2.5 mm inferior offset glenosphere required less deltoid force to reach maximum abduction than did the more anatomic, lateralized 135 stem coupled with a 4 mm lateral offset glenosphere.Level of EvidenceBasic Science, Biomechanics Controlled Laboratory Study     

A randomized prospective study comparing migration of hydroxyapatite and non-hydroxyapatite coated glenoid components using radiostereometric analysis

BackgroundPrimary shoulder arthroplasty can significantly improve quality of life; however, the glenoid baseplate remains the most common component to loosen, which may result in implant failure and subsequent revision surgery. Radiostereometric analysis (RSA) is considered the gold standard for accurate measurement of micro-motion between implant and bone. The aims of this study were to compare migration of the Lima SMR porous titanium hydroxyapatite (HA) coated and non-hydroxyapatite (non-HA) coated glenoid components through a prospective, randomized 2-arm trial using RSA, whilst also comparing clinical and functional outcomes.MethodsTwenty patients were randomized into 2 equal (HA and non-HA coated) groups with all patients undergoing primary anatomic shoulder arthroplasty, at which time tantalum beads were also inserted. RSA imaging was performed immediately postoperatively, then at 3, 6, 12, and 24 months postprocedure. These images were digitized and analyzed using model-based RSA software. All patients completed Oxford Shoulder Score (OSS), American Shoulder and Elbow Surgeons (ASES) score, Constant Score (CS) and Visual Analogue Scale (VAS) pain scores pre-and postoperatively at the aforementioned time points. Unpaired t-tests were used for clinical outcome data; Mann-Whitney U tests were used for RSA data. Significance levels were set at P < .05.ResultsMean age for the HA group was 72.3 years; 69.5 years for the non-HA group. Mean follow-up for both groups was above 36 months. No significant differences in glenoid migration were observed at each of the postoperative time points; the only exception being at 12 months (non-HA group displaying significantly greater rotation in the z-axis). The HA group displayed fractionally more translation in the x- and z-axes at all time points (not significant). Rotation in the z-axis was marginally greater at all postoperative time points in the non-HA group. Median total migration values revealed greater motion for the non-HA group at 3, 6, and 12 months (not significant). All clinical outcome measures improved significantly within each group; no statistical differences were observed between the groups for any outcome measure. One patient in each group underwent revision surgery to reverse shoulder arthroplasty due to unexplained pain (HA group) and cuff failure (non-HA group) only. Radiolucent lines were noted in 2 patients who are still under follow-up.ConclusionThis study has revealed promising early results of both HA coated and non-HA coated implants, however, hydroxyapatite coating of glenoid components does not significantly improve outcome scores nor provide extra stability compared to non-hydroxyapatite coated implants at 2 years postprocedure.Level of evidenceLevel II; Randomized Controlled Trial     

Outcomes of reverse total shoulder arthroplasty are similar in rotator cuff-intact and rotator cuff-deficient shoulders

BackgroundControversy exists regarding the biomechanical and clinical effects of reverse total shoulder arthroplasty (RTSA) in shoulders with an intact versus a torn rotator cuff (RC). We compared clinical and radiographic outcomes at a minimum of 2 years after RTSA for cuff-intact or cuff-deficient conditions.MethodsRetrospective review identified 182 patients with at least 2 years of follow-up: 32 with an intact rotator cuff but advanced glenoid bone loss and 150 with a torn rotator cuff. Revision arthroplasties and those for osteonecrosis or trauma were excluded, and a matched cohort was created to compare 32 cuff-intact to 32 cuff-deficient shoulders. Assessments included preoperative and postoperative visual analog pain scores (VAS), American Shoulder and Elbow Surgeons (ASES) scores, narcotic use, strength, range of motion (ROM), complications, and revisions. Radiographs were analyzed for signs of loosening or mechanical failure.ResultsMean age for all patients was 71.7 (61-82) years, and the mean follow-up was 2.7 (2.0-5.5) years. Preoperatively, the groups were similar in almost every functional preoperative category, with no differences in gender, laterality, age, preoperative narcotic use, body mass index, or other co-morbidities. Postoperatively, no significant differences were found regarding VAS pain, ASES, ROM, strength, complication rate, revision rate, narcotic use, implant loosening, or mechanical failure; both groups showed significant improvements in all categories measured.ConclusionsRTSA provides reliably good functional and radiographic outcomes with low complication rates in indicated patients, regardless of the preoperative status of the rotator cuff.Level of evidenceLevel III; Retrospective Comparative Study     

Use of preoperative advanced imaging for reverse total shoulder arthroplasty

BackgroundIn order to avoid implant related complications related to glenosphere malposition, there has been an increased interest in the use of advanced imaging, including computed tomography (CT) and magnetic resonance imaging (MRI) for preoperative planning and patient-specific instrumentation for reverse shoulder arthroplasty (RSA). While recent literature has demonstrated improved component position when this technology is applied, the clinical benefits remain largely hypothetical and unproven. Thus, the goals of the current study were to utilize a national database to describe current trends in the use of preoperative advanced imaging and investigate the relationship between such imaging and postoperative complications compared to matched controls without any preoperative imaging.MethodsPatients undergoing RSA for non-fracture indications were identified within the Mariner dataset within the PearlDiver database from 2010 to 2018Q2. Patients who underwent preoperative advanced imaging (MRI and/or CT) within a year prior to surgery were then identified as study cohorts. A matched cohort undergoing RSA without preoperative advanced imaging was created for comparison purposes. The incidence of imaging over time and rates of loosening/osteolysis, periprosthetic fracture, prosthetic dislocation, and revision shoulder arthroplasty of all groups were compared using a regression analysis.ResultsThe percentage of patients who underwent preoperative CT (141% increase, P < .0001), and either MRI or CT (107% increase, P = .002) increased significantly during the study period, while there was no significant increase in MRI utilization (P = .122). Patients who underwent preoperative CT experienced significantly lower rates of revision shoulder arthroplasty (2.4% vs. 3.3%, OR = 0.72, P = .004) and periprosthetic dislocation (2.8% vs. 3.3%, OR 0.80, P = .039) within 2 years of RSA compared to patients who did not undergo preoperative CT, while preoperative MRI was associated with significantly lower rates of periprosthetic fracture (0.2% vs. 0.4%, OR 0.44, P = .005), revision shoulder arthroplasty (2.1% vs. 2.6%, OR = 0.75, P = .006), and periprosthetic dislocation (2.5% vs. 3.2%, OR 0.78, P = .003) within 2 years of RSA compared to patients without an MRI.ConclusionThere has been a significant increase in the utilization of preoperative CT as compared to MRI for RSA during the time period studied. The utilization of preoperative advanced imaging may be associated with a statistically significant reduction in multiple implant related complications following RSA for non-fracture indications, although these findings are of unclear clinical significance given limitations of the database and low percentage difference in complication rates.Level of Evidence: Level III     

Clinical and radiographic factors associated with internal rotation outcomes following reverse shoulder arthroplasty using an inlay stem design

BackgroundThe purpose of this study was to evaluate the relationship between preoperative subscapularis (SSc) status as well as radiographic factors with internal rotation (IR) following reverse shoulder arthroplasty (RSA). Our hypothesis was that increased glenosphere lateralization and SSc insertion lateralization and the absence of a preoperative SSc tear would be associated with improved postoperative IR (IR_F).MethodsA retrospective review was performed of primary RSAs (n = 132) by a single surgeon using a 135° inlay prosthesis. Range of motion including forward flexion (FF_F), external rotation (ER_F) and IR_F were evaluated at one year postoperative. IR_F was divided into high (≥L4) and low (≤L4) groups. Preoperative SSc status, glenosphere size, and postoperative positions of the glenosphere and humerus were assessed. Novel radiographic factors were used to assess lateralization including the lesser tuberosity scapula (LTS) and lateral glenosphere scapula (LGS) ratios.ResultsOnly 32% of patients achieved IR_F ≥ L4 postoperatively. Patients who achieved high IR_F had a lower incidence of preoperative SSc tear compared to those who had an IR_F < L4 (9% vs. 47%; P = .002). Higher LTS and LGS ratios were associated with improved IR_F (P < .001). The chance of having IR_F ≥ L4 increased by 86% (P = .049) and by 62% (P = .038) for every 0.1 increase in LGS ratio and LTS ratios, respectively.ConclusionWith a 135° inlay prosthesis design, an intact SSc preoperatively, as well as increased lateralization parameters, LTS and LGS ratios are associated with increased postoperative IR following RSA.Level of EvidenceLevel III; Retrospective Case-control Comparative Study     

Correlation of patient-reported outcome measurement information system-upper extremity with American Shoulder and Elbow Surgeons scores in shoulder arthroplasty

BackgroundMultiple outcome measure surveys are available to assess preoperative and postoperative outcomes for a variety of orthopedic procedures such as shoulder arthroplasty. Although legacy instruments such as American Shoulder and Elbow Surgeons (ASES) remain popular, there remains no singular gold standard survey instrument for shoulder arthroplasty patients, and alternative instruments have been developed to better capture clinical outcomes. The goal of this study is to compare the efficacy of Patient-Reported Outcome Measurement Information System-Upper Extremity (PROMIS-UE) using computer adaptive technology with ASES scores both preoperatively and postoperatively in shoulder arthroplasty patients. Our hypothesis is that there would be a strong correlation between PROMIS-UE and ASES scores both preoperatively and postoperatively in total shoulder arthroplasty patients.MethodsPatients who underwent total shoulder arthroplasty and agreed to complete baseline and 1-year follow-up of ASES and PROMIS-UE scores were included. Patients also completed PROMIS-Physical Function (PROMIS-PF) as a third point comparison. Responses to these instruments were statistically analyzed and compared using Pearson correlation coefficients. Floor and ceiling effects were then calculated.ResultsNinety patients were included in this study, all of whom completed the PROMIS-UE, PROMIS-PF, and ASES surveys both preoperatively and 12 months postoperatively. The mean age in this cohort was 68.9 years (standard deviation [SD] 8.4 years, range 39-89). The mean preoperative and postoperative PROMIS-UE scores were 26.6 (SD 6.7, range 14.7-44.6) and 41.8 (SD 10.3, range 20.2-56.4) respectively. Mean preoperative and postoperative PROMIS-PF computer adaptive technology scores were 35.7 (SD 9.54, range 34.2-64) and 44.3 (SD 9.22, range 23.5-73.3) respectively. The mean ASES score was 37.5 preoperatively (SD 18.0, range 5-99.5) and 77.5 postoperatively (SD 20.5, range 25.0-100.0). PROMIS-UE demonstrated a moderate correlation with ASES preoperatively and a strong correlation postoperatively (r = 0.52, confidence interval 0.27-0.60; r = 0.70, confidence interval 0.55-0.78, respectively). PROMIS-UE demonstrated a minor floor effect preoperatively (7.8%) but significant ceiling effect postoperatively (24.4%) and ASES demonstrated a mild ceiling effect at final follow-up (8.9%). There were otherwise no other floor or ceiling effects at all other time points across each survey.ConclusionPROMIS-UE correlates well with ASES at both baseline and 1-year postoperation for patients undergoing total shoulder replacement. In addition, the change seen between both baseline and 1 year outcome scores for both scoring systems also correlates strongly, suggesting that PROMIS-UE may be a suitable alternative to ASES for this patient population.     

Clinical and patient-reported outcomes of reverse shoulder arthroplasty in patients receiving Social Security Disability Insurance or workers’ compensation

BackgroundEvidence suggests that reverse shoulder arthroplasty (RSA) patients receiving workers’ compensation (WC) have worse patient-reported outcomes (PROs) than those not receiving WC. It is unknown whether Social Security Disability Insurance (SSDI) recipients also have worse outcomes of RSA. Our goals were to (1) compare PROs and range of motion (ROM) after RSA according to whether patients were receiving SSDI, WC, or neither form of assistance, and (2) identify factors associated with poor PROs.MethodsFrom a US institutional database of 454 patients who underwent RSA from January 2009 through December 2016, we identified 19 SSDI recipients and 25 WC recipients. From the same database, we created a control group of 81 patients not receiving SSDI or WC, matched by demographic variables. Between groups, we compared age, sex, operative arm dominance, preoperative diagnosis, number of previous shoulder surgeries, primary or revision arthroplasty, and Charlson Comorbidity Index value. Patients were evaluated preoperatively and at a minimum of 2 years postoperatively by physical examination, including range of motion, visual analog scale (VAS) for pain, American Shoulder and Elbow Surgeons (ASES) score, L'Insalata score, Simple Shoulder Test (SST), and Western Ontario Osteoarthritis of the Shoulder (WOOS) score. Significance was set at P< .05. Clinical relevance of improvements in forward flexion and abduction, VAS for pain, ASES, and SST were evaluated using established minimal clinically important difference (MCID) values.ResultsBoth the SSDI and WC groups experienced statistically significant improvements from preoperatively to postoperatively; these improvements exceeded MCID thresholds for forward flexion and abduction, VAS for pain, ASES (except in WC group), and SST score (all, P< .05). These outcomes were not significantly different between the SSDI and WC groups. Compared with the control group, both the SSDI and WC groups had statistically significantly worse outcomes for these same measures. The only factor associated with poor clinical outcomes was having undergone ≥2 previous surgical procedures on the same shoulder for which RSA was performed in both SSDI (odds ratio = 2.4, 95% confidence interval: 1.0-5.4) and WC (odds ratio = 1.6, 95% confidence interval: 1.1-4.5) groups.ConclusionAmong RSA patients, SSDI recipients did not have worse clinical outcomes than WC recipients. Having undergone ≥2 previous procedures on the same shoulder was associated with poor outcomes in both groups. These findings should be considered when determining the appropriateness of RSA for SSDI and WC recipients.Level of evidenceLevel III; Retrospective Cohort Comparison; Treatment Study     

Long-term relation between deltoid muscle volume and clinical outcomes in a reverse shoulder arthroplasty

BackgroundDeltoid muscle function is important in reverse shoulder arthroplasty (RSA). Concerns are raised on the resistance of the deltoid muscle against the postoperative distalization. We hypothesize that a decreased volume of the deltoid muscle is related to worse clinical outcomes after a long-term follow-up. An observational study was conducted to evaluate the relation between volume of the deltoid muscle and clinical outcomes after a long-term follow-up on RSA.MethodsEligible for inclusion was patients who underwent RSA for cuff arthropathy after minimum 3 years follow-up. Fifty-nine patients were enrolled in this study. Preoperative volume was measured on magnetic resonance imaging or computed tomography. Postoperative deltoid volume was evaluated on ultrasonography. Distalization of the humerus was measured on radiographs. Clinical outcomes were measured by the Constant-Murley Score (CMS), Oxford Shoulder Score, and range of motion. Multivariable linear regression models were used to examine the association between the deltoid volume and clinical outcomes, and between distalization and deltoid volume or clinical outcomes.ResultsThe mean follow-up period was 88.7 ± 29.1 months. Postoperative deltoid volume positively correlated with both CMS (P = .045) and abduction strength, in both operated (P = .01) and contralateral side (P < .001). No association between deltoid volume and Oxford Shoulder Score or range of motion, and no association between preoperative volume and postoperative CMS was found. The mean distalization of the humerus was 21.2 mm [95% CI: 19.4-22.9 mm]. Distalization negatively correlated with deltoid volume (P = .012) and CMS (P = .009).ConclusionsPostoperative deltoid volume correlated with clinical outcomes as measured by CMS and abduction strength after a long-term follow-up on RSA.     

Understanding the variables that are associated with failure to achieve an acceptable symptom state after reverse shoulder arthroplasty

BackgroundThe patient acceptable symptom state (PASS) was developed to improve the subjective interpretation of patient reported outcomes (PROs) and the minimum score necessary for the patient to “feel good.” The purpose of this study was to compare range of motion (ROM), final PROs, and individual responses on PROs between patients achieving or failing to meet a PASS after reverse shoulder arthroplasty (RSA).MethodsA retrospective review of multi-center prospectively maintained database of RSAs between 2015 and 2018 was conducted. Primary RSAs with minimum 2-year follow-up were included. Patients were stratified into 2 groups by whether they achieved or failed to meet PASS scores at a minimum of 2 years of 76 for the ASES score or 75.5 for the SANE score. The primary goals of the study were to compare outcomes, range of motion (ROM) and individual ASES and WOOS survey responses for patients above and below the PASS score.Results87 patients were included. Using the ASES cutoff for PASS, 33% failed to meet a PASS while 45% failed to meet a PASS defined by the SANE. The most notable difference between patients above and below ASES PASS was a significant difference in VAS pain scores (3.1 vs. 0.3; P < .001). Overall, ROM was similar between patients above and below the ASES PASS, with slight, but statistically improved rotational motion in those achieving an ASES PASS (ER(90) 14 degrees improved, P = .005, IR(90) 10 degrees improved, P = .011). Similarly, patients failing to meet the SANE PASS had twice as high VAS pain scores (1.9 vs. 0.8; P = .017). Patients failing to meet the ASES PASS had almost universally statistically higher rates of reporting “very difficult” or “unable to do” for pain, ADL and work/sports questions on the ASES and globally more symptoms on every domain of questions for the WOOS. Similarly, for the PASS defined by SANE, patients reported higher levels of pain and dysfunction on nearly every question and domain of the ASES and WOOS.ConclusionsAt least one quarter of patients do not achieve a PASS after RSA. Pain appears to be the primary driver for this finding, while ROM is very similar between patients achieving or failing to meet a PASS regardless of PRO used to define the PASS. Patients who fail to achieve PASS after RSA report doing poorly in all domains of their outcome.Level of evidenceLevel III; Retrospective Comparative Study     

Predictors of patient satisfaction and outcomes following reverse total shoulder arthroplasty

BackgroundObjective clinical outcomes and patient satisfaction via patient reported outcome measures (PROMs) can vary following reverse total shoulder arthroplasty (rTSA). The purpose of this study was to analyze patient specific preoperative factors that may predict postoperative PROMs and satisfaction following rTSA.MethodProspective data was collected on 144 consecutive patients who underwent primary rTSA at our institution between 2012 and 2018, all with minimum 2 year follow-up. Age, gender, race, BMI, previous surgery on the index shoulder, and comorbidity burden were analyzed as potential predictors. Shoulder specific clinical measures were collected both pre- and postoperatively via range of motion testing with active abduction, internal, and external rotation. PROMs included global shoulder function, Simple Shoulder Test (SST) and the American Shoulder and Elbow Surgeons (ASES) scoring systems, and cumulative patient satisfaction. Statistical analysis included comparison of pre- and postoperative outcome measures across the cohort as a whole and between each of the potential predictors in question. The relationship between predictors and postoperative cumulative satisfaction was investigated, with specific attention to identify the strongest predictors and account for confounding variables. Statistical significance was determined at P < .05.ResultsAll range of motion scores and PROMs were significantly improved from preoperative to postoperative assessment. Patient satisfaction was excellent with 92% rating their shoulder as “much better” or “better.” Women and minority patients displayed significantly worse preoperative active abduction, SST, and ASES, but were found to have no significant difference in these measures postoperatively. Younger age was associated with a significantly worse postoperative ASES score. Female sex was associated with significantly higher postoperative satisfaction, while minority status was associated with significantly lower cumulative satisfaction. Postoperative global shoulder function, SST, and ASES were not significantly influenced by sex, race, previous surgery, BMI, or comorbidity burden. Postoperative ASES and global shoulder function demonstrated to be independent predictors of “much better” satisfaction rating.ConclusionPostoperative PROMs and cumulative satisfaction are not influenced by BMI, previous surgery, or comorbidity burden in our cohort. Relative to their respective counterparts, older patients, females, and white patients are more likely to demonstrate higher satisfaction with their outcome following rTSA as measured by PROMs or cumulative satisfaction. Improvements in the ASES and global shoulder function scores most consistently predict higher postoperative satisfaction.Level of evidenceLevel IV; Case Series; Treatment Study