Reliability assessment of new radiographic scales to evaluate radiolucency and bony in-between fin growth of partially cemented all-polyethylene glenoid components.

BACKGROUND: Current methods available for assessment of radiolucency and in-between fin (IBF) growth of a glenoid component have not undergone interobserver reliability testing for an all-polyethylene fluted central peg (FCP) glenoid. The purpose of this study was to evaluate anteroposterior radiographs of an FCP glenoid component at ≥48 months comparing commonly used scales to a new method adapted to the FCP. Our hypothesis was that the new method would result in acceptable intra- and interobserver agreement and a more accurate description of radiographic findings. METHODS: We reviewed ≥48-month follow-up radiographs of patients treated with a primary aTSA using an FCP glenoid. Eighty-three patients were included in the review. Radiographs were evaluated by 5 reviewers using novel IBF radiodensity and radiolucency assessments and the Wirth and Lazarus methods. To assess intraobserver reliability, a subset of 40 images was reviewed. Kappa statistics were calculated to determine intra- and interobserver reliability; correlations were assessed using Pearson correlation. RESULTS: Interobserver agreement (κ score) was as follows: IBF 0.71, radiolucency 0.68, Wirth 0.48, and Lazarus 0.22. Intraobserver agreement ranges were as follows: IBF radiodensity 0.36-0.67, radiolucency 0.55-0.62, Wirth 0.11-0.73, and Lazarus 0.04-0.46. Correlation analysis revealed the following: IBF to Wirth r = 0.93, radiolucency to Lazarus r = 0.92 (P value <.001 for all). CONCLUSION: This study introduces a radiographic assessment method developed specifically for an FCP glenoid component. Results show high interobserver and acceptable intraobserver reliability for the method presented in this study. The new scales provide a more accurate description of radiographic findings, helping to identify glenoid components that may be at risk for loosening.

Posteroinferior glenosphere positioning is associated with improved range of motion following reverse shoulder arthroplasty with a 135° inlay humeral component and lateralized glenoid.

BACKGROUND: Optimal glenosphere positioning in a lateralized reverse shoulder arthroplasty (RSA) to maximize functional outcomes has yet to be clearly defined. Center of rotation (COR) measurements have largely relied on anteroposterior radiographs, which allow assessment of lateralization and inferior position, but ignore scapular Y radiographs, which may provide an assessment of the posterior and inferior position relative to the acromion. The purpose of this study was to evaluate the COR in the sagittal plane and assess the effect of glenosphere positioning with functional outcomes using a 135° inlay stem with a lateralized glenoid. METHODS: A retrospective review was performed on a prospectively maintained multicenter database on patients who underwent primary RSA from 2015 to 2021 with a 135° inlay stem. The COR was measured on minimum 2-year postoperative sagittal plain radiographs using a best-fit circle fit method. A best-fit circle was made on the glenosphere and the center was marked. From there, 4 measurements were made: (1) center to the inner cortex of the coracoid, (2) center to the inner cortex of the anterior acromion, (3) center to the inner cortex of the middle acromion, and (4) center to the inner cortex of the posterior acromion. Regression analysis was performed to evaluate any association between the position of the COR relative to bony landmarks with functional outcomes. RESULTS: A total of 136 RSAs met the study criteria. There was no relation with any of the distances with outcome scores (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, visual analog scale). In regard to range of motion (ROM), each distance had an effect on at least 1 parameter. The COR to coracoid distance had the broadest association with ROM, with improvements in forward flexion (FF), external rotation (ER0), and internal rotation with the arm at 90° (IR90) (P < .001, P = .031, and P < .001, respectively). The COR to coracoid distance was also the only distance to affect the final FF and IR90. For every 1-mm increase in this distance, there was a 1.8° increase in FF and 1.5° increase in IR90 (ß = 1.78, 95% confidence interval [CI] 0.85-2.72, P < .001, and ß = 1.53, 95% CI 0.65-2.41, P < .001; respectively). CONCLUSION: Evaluation of the COR following RSA in the sagittal plane suggests that a posteroinferior glenosphere position may improve ROM when using a 135° inlay humeral component and a lateralized glenoid.

Robert H. Cofield, MD, Award for Best Oral Presentation 2023: Up to 8 mm of glenoid-sided lateralization does not increase the risk of acromial or scapular spine stress fracture following reverse shoulder arthroplasty with a 135° inlay humeral component.

BACKGROUND: Glenoid-sided lateralization in reverse shoulder arthroplasty (RSA) decreases bony impingement and improves rotational range of motion, but has been theorized to increase the risk of acromial or scapular spine fractures (ASFs). The purpose of this study was to assess if glenoid-sided lateralization even up to 8 mm increases the risk for stress fracture following RSA with a 135° inlay humeral component. METHODS: A retrospective review was performed from a multicenter prospectively collected database on patients who underwent primary RSA from 2015 to 2021. All RSAs were performed with a 135° inlay humeral component. Varying amounts of glenoid lateralization were used from 0 to 8 mm. Preoperative radiographs were reviewed for the presence of acromial thinning, acromiohumeral distance (AHD), and inclination. Postoperative implant position (distalization, lateralization, and inclination) as well as the presence of ASF was evaluated on minimum 1-year postoperative radiographs. Regression analyses were performed on component and clinical variables to assess for factors predictive of ASF. RESULTS: Acromial or scapular spine fractures were identified in 26 of 470 shoulders (5.5%). Glenoid-sided lateralization was not associated with ASF risk (P = .890). Furthermore, the incidence of fracture did not vary based on glenoid-sided lateralization (0-2 mm, 7.4%; 4 mm, 5.6%; 6 mm, 4.4%; 8 mm, 6.0%; P > .05 for all comparisons). RSA on the dominant extremity was predictive of fracture (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.20-5.75; P = .037), but there was no relationship between patient age, sex, preoperative acromial thinning, or diagnosis and risk of fracture. Although there was no difference in mean postoperative AHD between groups (P = .443), the pre- to postoperative delta AHD was higher in the stress fracture group (2.0 ± 0.7 cm vs. 1.7 ± 0.7 cm; P = .015). For every centimeter increase in delta AHD, there was a 121% increased risk for fracture (OR 2.21, 95% CI 1.33-3.68; P = .012). Additionally, for every 1-mm increase in inferior glenosphere overhang, there was a 19% increase in fracture risk (P = .025). CONCLUSION: Up to 8 mm of glenoid-sided metallic lateralization does not appear to increase the risk of ASF when combined with a 135° inlay humeral implant. Humeral distalization increases the risk of ASF, particularly when there is a larger change between pre- and postoperative AHD or higher inferior glenosphere overhang. In cases of pronounced preoperative superior humeral migration, it may be a consideration to avoid excessive postoperative distalization, but minimizing bony impingement via glenoid-sided lateralization appears to be safe.

Clinical and radiographic outcomes following anatomic total shoulder arthroplasty utilizing an inset glenoid component at 2-year minimum follow-up: a dual center study.

BACKGROUND: Anatomic total shoulder arthroplasty (aTSA) is a successful and reproducible treatment for patients with painful glenohumeral arthritis. However, long-term outcomes using traditional onlay glenoid components have been tempered by glenoid loosening. Inset components have been proposed to minimize glenoid loosening by reducing edge-loading and opposite-edge lift-off forces with humeral translation. Successful short- and long-term outcomes have been reported while using inset glenoid implants. The current study is the largest study presenting a minimum of 2-year follow-up data following aTSA with an all-polyethylene inset glenoid component (Shoulder Innovations, Holland, MI, USA). METHODS: A dual center, retrospective review of patients undergoing aTSA using an Inset glenoid component by 2 fellowship-trained shoulder surgeons at 2 separate institutions from August, 2016, to August, 2019, was performed. Minimum follow-up was 2 years. Range of motion (ROM), visual analog scale (VAS) pain scores, Single Assessment Numeric Evaluation (SANE), and American Shoulder and Elbow Surgeons (ASES) scores were obtained. Radiographic outcomes, including central peg lucency and glenoid loosening, were assessed by 3 independent reviewers on the postoperative Grashey and axillary radiographs obtained at the final follow-up. RESULTS: Seventy-five shoulders were included for the final analysis. The mean age of the entire cohort was 64 (±11.4) years. Twenty-one (28%) glenoids were type A1, 10 (13.3%) were type A2, 13 (17.3%) were type B1, 22 (29.3%) were type B2, 6 (8%) were type B3, and 3 (4%) were type D. At a minimum follow-up of 24 months (mean: 28.7 months), a significant improvement in ROM in all planes was observed. Significant improvements in VAS (5.1-0.9, P < .001), SANE (39.5-91.2, P < .001), and ASES (43.7-86.6, P < .001) scores were observed. There were 4 (5.3%) cases of central peg lucency about the inset glenoid component and one (1.3%) case of glenoid loosening. No revisions were performed for glenoid loosening. CONCLUSION: At a minimum of 2 years postoperatively, there were significant improvements in ROM, VAS, SANE, and ASES scores with very low rates of central peg lucency and glenoid loosening in patients undergoing aTSA with an inset glenoid component. Further work is needed to determine the long-term benefit of this novel implant.

Stemless components lead to improved radiographic restoration of humeral head anatomy compared with short-stemmed components in total shoulder arthroplasty.

BACKGROUND: Restoring the native center of rotation (COR) in total shoulder arthroplasty (TSA) has been shown to improve postsurgical function, subjective outcomes, and implant longevity. The primary purpose of this study was to compare postoperative radiographic restoration of the humeral COR between short-stem and stemless humeral implants by evaluating the mean COR shift between the 2 techniques. Secondary outcomes evaluated were comparisons of COR shift outliers, humeral head implant thickness and diameter, direction of COR shift, and neck-shaft angle (NSA). METHODS: This study was a multicenter retrospective comparative study using a consecutive series of primary anatomic TSA patients who received either a short-stem or stemless humeral implant. Radiographically, COR and NSA were measured by 2 fellowship-trained surgeons using the best-fit circle technique on immediate postoperative Grashey radiographs. RESULTS: A total of 229 patients formed the final cohort for analysis that included 89 short stems and 140 stemless components. The mean COR shift for short stems was 2.7 mm (±1.4 mm) compared with 2.1 mm (±0.9 mm) for stemless implants (P < .001). The percentage of short-stem implant patients with a >2 mm COR difference from native was 66.0% (n = 62) compared with 47.4% (n = 64) for stemless (P = .006). The percentage of short-stem patients with a >4 mm COR difference from native was 17.0% (n = 16) compared with 3.0% (n = 4) for stemless (P < .001). The mean humeral implant head thickness for short stems was 18.7 ± 2.2 mm compared with 17.2 ± 1.3 mm for stemless implants (P < .001). The mean humeral head diameter for short stems was 48.7 ± 4.4 mm compared with 45.5 ± 3.5 mm for stemless implants (P < .001). The NSA for the short-stem cohort was 136.7° (±3.6°) compared with 133.5° (±6.0°) for stemless (P < .001). CONCLUSIONS: Stemless prostheses placed during TSA achieved improved restoration of humeral head COR and were less likely to have significant COR outliers compared with short-stem implants.

A comprehensive evaluation of the association of radiographic measures of lateralization on clinical outcomes following reverse total shoulder arthroplasty.

BACKGROUND: Although reverse total shoulder arthroplasty (RTSA) has excellent reported outcomes and satisfaction, patients often have postoperative limitations in range of motion (ROM), specifically internal rotation. Increased lateralization is thought to improve ROM following RTSA. The purpose of this study was to evaluate the association between radiographic measurements of lateralization and postoperative ROM and clinical outcome scores following RTSA. The authors hypothesized that increased radiographic lateralization would be associated with improved postoperative ROM, specifically internal rotation, but have no significant association with clinical outcome scores. METHODS: Patients who underwent RTSA with a 135° neck-shaft angle prosthesis and minimum 2-year clinical and radiographic follow-up were included and retrospectively reviewed. Postoperative radiographs were evaluated for several lateralization measurements including the lateralization shoulder angle (LSA), distance from the lateral border of the acromion to the lateral portion of the glenosphere, distance from the glenoid to the most lateral aspect of the greater tuberosity, and the distance from the lateral aspect of the acromion to the most lateral aspect of the greater tuberosity. Linear regression analyses were used to evaluate the independent association of each radiographic measurement of lateralization on forward flexion, external rotation, internal rotation, and the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) index score at 2 years postoperation. Receiver operating characteristic (ROC) curves were constructed to identify significant thresholds of each radiographic lateralization measurement. RESULTS: A total of 203 patients were included. For internal rotation, a greater LSA (P = .007), shorter acromion to glenosphere distance (meaning more glenoid lateralization) (P = .005), and a greater acromion to greater tuberosity distance (with the tuberosity more lateral to the acromion) (P = .021) were associated with improved internal rotation. Overall, ROC analysis demonstrated very little significant data, the most notable of which was the LSA, which had a significant cutoff of 82° (sensitivity 57%, specificity 68%, P = .012). CONCLUSION: Of the numerous radiographic measures of lateralization after RTSA, the LSA is the most significantly associated with outcomes, including improved internal rotation and a decrease in forward flexion and ASES score. The clinical significance of these statistically significant findings requires further study, as the observed associations were for very small changes that may not represent clinical significance.

Early clinical and radiographic outcomes of anatomic total shoulder arthroplasty with a biconvex posterior augmented glenoid for patients with posterior glenoid erosion: minimum 2-year follow-up.

BACKGROUND: Glenoid bone loss in anatomic total shoulder arthroplasty (aTSA) remains a controversial and challenging clinical problem. Previous studies have shown high rates of glenoid loosening for aTSA in shoulders with retroversion, posterior bone loss, and posterior humeral head subluxation. This study is the first to present minimum 2-year follow-up data of an all-polyethylene, biconvex augmented anatomic glenoid component for correction of glenoid retroversion and posterior humeral head subluxation. METHODS: This study is a multicenter, retrospective review of prospectively collected data on consecutive patients from 7 global clinical sites. All patients underwent aTSA using the biconvex posterior augmented glenoid (PAG). Inclusion criteria were preoperative computed tomographic (CT) scan, minimum 2 years since surgery, preoperative and minimum 2-year postoperative range of motion examination, and patient-reported outcome measures (PROMs). Glenoid classification, glenoid retroversion, and posterior humeral head subluxation were measured from preoperative CT and radiography and postoperative radiography. Statistical comparisons between pre- and postoperative values were performed with a paired t test. RESULTS: Eighty-six of 110 consecutive patients during the study period (78% follow-up) met the inclusion criteria and were included in our analysis. Mean follow-up was 35 ± 10 months, with a mean age of 68 ± 8 years (range 48-85). Range of motion statistically improved in all planes from pre- to postoperation. Mean visual analog scale score improved from 5.2 preoperation to 0.7 postoperation, Single Assessment Numeric Evaluation score from 43.2 to 89.5, Constant score from 41.8 to 76.9, and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score from 49.8 to 86.7 (all P < .0001). Mean glenoid retroversion improved from 19.3° to 7.4° (P < .0001). Posterior subluxation improved from 69.1% to 53.5% and posterior decentering improved from 5.8% to -3.0% (P < .0001). There was 1 patient with both a prosthetic joint infection and radiographic glenoid loosening that required revision. Seventy-nine of 86 patients had a Lazarus score of 0 (no radiolucency seen about peg or keel) at final follow-up. CONCLUSIONS: This study shows that at minimum 2-year follow-up, a posterior-augmented all-polyethylene glenoid can correct glenoid retroversion and posterior humeral head subluxation. Clinically, there was significant improvement in both range of motion and PROMs.

An anthropometric analysis to derive formulae for calculating the dimensions of anatomically shaped humeral heads.

BACKGROUND: The elliptical shape of the humeral head has been vaguely described, but a more detailed mathematical description is lacking. The primary goal of this study was to create formulae to describe the mathematical relationships between the various dimensions of anatomically shaped humeral heads. METHODS: Three-dimensional computer models of 79 proximal humeri derived from computed tomography scans (white subjects, 47 male and 32 female; ages, 17-87 years) were studied. Linear regression analysis of the obtained humeral measurements was performed, and Pearson correlation coefficient (R) values were calculated. To substantiate the results of the linear regression analysis, Welch t-test was used to compare various parameters of small, medium, and large humeral heads. RESULTS: Formulae for calculating humeral head height, diameters of the base of the humeral head in the frontal and sagittal planes, and radii of curvature in the frontal and sagittal planes were derived from the linear regression plots that were found to have strong (1 ≥ R ≥ 0.50) correlations. By Welch t-test, differences between the 3 head sizes were statistically significant in each case (P ≤ .022). The elliptical shape of the base of the humeral head was found to elongate with increasing humeral head size. CONCLUSIONS: Mathematical formulae relating various humeral head dimensional measurements are presented. The formulae derived in this study may be useful for the design of future prosthetic shoulder systems in which the goal is to replicate normal anatomy. This is the first study to describe that the elliptical shape of the base of the humeral head elongates as head size increases.

Intramedullary Nailing Technique for Proximal Humeral Fractures Using a Straight Antegrade Nail with Locking Tuberosity Fixation.

Background: Intramedullary straight nail fixation of proximal humeral fractures using a locking mechanism provides advantages compared with plating, including (1) less soft-tissue dissection, which preserves periosteal blood supply and soft-tissue attachments; (2) improved construct stability for comminuted fractures or osteopenic bone; and (3) shorter operative time for simpler fractures. Description: The patient is placed in the beach-chair position with the head of the bed elevated approximately 45°. The fracture is reduced with use of closed or percutaneous methods, ideally, or with an open approach if required. Temporary fragment fixation with percutaneous Kirschner wires can be utilized. A 1-cm incision is made just anterior to the acromioclavicular joint, overlying the zenith of the humeral head and in line with the diaphysis. A guide-pin is then placed through this incision and is verified to be centrally located and in line with the humeral diaphysis on fluoroscopic views. The guide-pin is advanced into the diaphysis. A cannulated 9-mm reamer is inserted over the guide-pin to create a starting position. The nail is then inserted, with adequate fragment reduction maintained until the proximal nail portion is buried under the subchondral humeral head. The proximal screw trajectory and alignment are checked fluoroscopically. The proximal locking screws are pre-drilled and inserted first using percutaneous drill sleeves through the radiolucent targeting jig. The screw is inserted through the guide and is advanced into the nail until appropriately seated. This process is then repeated for the other proximal screws as necessary. Finally, the distal diaphyseal screws are pre-drilled and inserted in a similar percutaneous fashion using the jig, and the jig is removed. Final orthogonal images are obtained. Copious irrigation of the incisions is performed and they are closed and dressed with a sterile dressing. The operative arm is placed in an abduction sling. Alternatives: Alternative treatment options for proximal humeral fractures include nonoperative treatment with use of a sling, percutaneous reduction and internal fixation with Kirschner wires, open reduction and internal fixation with a locking plate and screw construct, hemiarthroplasty, and anatomic or reverse total shoulder arthroplasty1. Rationale: The presently described technique for proximal humeral fracture fixation using a straight, antegrade, locking nail allows for minimal soft-tissue disruption, preserving vascularity and soft-tissue support and achieving angularly stable fixation in often osteopenic bone. The superior and in-line entry point avoids complications of rotator cuff injury and/or subacromial impingement. The proximal locking screws avoid complications of screw penetration or migration. This technique is appropriate for surgically indicated Neer 2-, 3-, and 4-part humeral fractures, including in elderly patients, when the humeral head fragment remains viable1-5. Expected Outcomes: Based on available Level-III and IV evidence using this technique, patients should expect recovered motion and the ability to perform daily activities independently, with a mean active elevation of 132° to 136°1,4,6, external rotation of 37° to 52°1,4,6, and internal rotation to L31. Pain scores improved significantly from preoperatively to postoperatively, with a mean pain score of 1.4 on the visual analogue scale3,4,6. Patient-reported outcomes were good to excellent, with Single Assessment Numerical Evaluation (SANE) scores of 80% to 81%1,6, mean Constant scores from 71 to 811,3,4,6, and high rates of patient satisfaction (97% satisfied or very satisfied)4. Studies also demonstrated good to excellent fracture healing, with no tuberosity migration and low rates of nonunion (0% to 5%)1,6 and humeral head necrosis (0% to 4%)1,4. Revision rates ranged from 10.5% to 16.7%4,6. Important Tips: The starting position of the guide-pin must be central and at the zenith of the humeral head on the anteroposterior Grashey and the scapular Y views, and the guide-pin must be aligned with the diaphysis prior to advancing it.Failure to bluntly dissect the percutaneous incisions risks injury to the axillary nerve.Verify correct version of the nail prior to drilling any screws, to avoid incorrect version and potential loss of functional rotation. Acronyms and Abbreviations: ABD = abductionAP = anteroposteriorCT = computed tomographyER = external rotationFF = forward flexion (forward elevation)IR = internal rotationSANE = Single Assessment Numerical EvaluationSSV = Subjective Shoulder ValueVAS = Visual Analogue Scale.

Comparison of clinical outcomes and complications in 2-part vs. 3- or 4-part proximal humerus fractures treated using an intramedullary nail designed to capture the tuberosities.

Background: Intramedullary nail fixation for proximal humerus fractures has been shown to provide satisfactory results. The quality of reduction correlates with clinical outcomes, the rate of complications, avascular necrosis, and postoperative loss of fixation. The purpose of this study was to evaluate the clinical outcomes and complications of 2-part proximal humerus fractures compared to 3- or 4-part proximal humerus fractures. Methods: A single-center retrospective review was carried out of patients who underwent an intramedullary nail for a proximal humerus fracture by one of three surgeons between the years of 2009 and 2022, and who had a minimum of 12-months follow-up. Fracture pattern, American Shoulder and Elbow Surgeons score, Single Assessment Numeric Evaluation score, satisfaction, pain score, range of motion, and complications were recorded. The mechanism of injury (high energy vs. low energy), method of reduction (open vs. percutaneous), and evidence of radiographic healing were assessed. A P value of <.05 was considered to be statistically significant. Results: The study included 78 patients (62 female, 16 male). The number of patients in each group (2-part, N = 32 vs. 3- or 4-part, N = 46), mean age (2-part, 64 vs. 3- or 4-part,61), follow-up (2-part, 42.5 months vs. 3- or 4-part, 34.5 months), injury type (2-part, 88% low energy vs. 3- or 4-part, 78% low energy), and method of reduction (2-part, 81% percutaneous vs. 3- or 4-part 72% percutaneous) were similar among the two groups. There was fracture union in all patients. All patients demonstrated satisfactory patient-reported outcome measures. However, 2-part fractures did have a significantly lower pain score, higher Single Assessment Numeric Evaluation score, and higher percentage of patients being satisfied or very satisfied when compared to 3- or 4-part fractures. The rate of subsequent procedures was 13% (n = 4) in 2-part fractures compared to 19% (n = 9) in 3- or 4-part fractures but was not statistically significant (P = .414). The overall rate of conversion to arthroplasty was 3.2% in 2-part fractures and 10.4% in 3- or 4-part fractures. Conclusion: Multipart proximal humerus fractures remain difficult to treat. However, this study demonstrates an overall acceptable outcome with improvement in range of motion, patient-reported outcomes, and similar complication rates between 2-part and 3- or 4-part proximal humerus fractures treated with an intramedullary nail. However, the improvement in certain parameters is not as marked in 3- or 4-part fractures as 2-part fractures.

Rates of subacromial notching are low following reverse shoulder arthroplasty with a 135° inlay humeral component and a lateralized glenoid.

Background: Lateralization in reverse shoulder arthroplasty (RSA) decreases bony impingement and improves rotational range of motion, but has been theorized to increase the risk of subacromial notching (SaN). The purpose of this study was to evaluate the presence of SaN following RSA and its relationship with lateralization with a 135° inlay humeral component. The secondary purpose was to assess the association of SaN with functional outcomes. Methods: A retrospective review was performed from a multicenter prospectively collected database on patients who underwent primary RSA from 2015 to 2021. All RSAs were performed with a 135° inlay humeral component. SaN was defined as bony erosion with sclerotic margins on the undersurface of the acromion on final follow-up radiographs not present preoperatively. Postoperative implant positioning (inclination, distalization, and lateralization) were evaluated on minimum 1-year postoperative radiographs. Regression analyses were performed on implant and clinical variables to assess for risk factors. A separate analysis was performed to determine the association of SaN with clinical outcomes. Results: SaN was identified in 13 out of 442 shoulders (2.9%). Age, sex, body mass index, smoking status, diabetes mellitus, arm dominance had no relationship with SaN. Neither glenoid sided lateralization nor humeral offset were associated with SaN risk. Other implant characteristics such as distalization, glenosphere size, and postoperative inclination did not influence SaN risk. The presence of SaN did not affect patient-reported outcomes (American Shoulder and Elbow Surgeons: P = .357, Visual Analog Scale: P = .210) or range of motion. Conclusion: The rate of SaN is low and not associated with glenoid or humeral prosthetic lateralization when using a 135° inlay humeral component. When SaN occurs, it is not associated with functional outcomes or range of motion at short-term follow-up.

Cerebral desaturation during shoulder arthroscopy: a prospective observational study.

BACKGROUND: Patients undergoing arthroscopic shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications as a result of cerebral ischemia. QUESTIONS/PURPOSES: We sought to define the (1) incidence; (2) timing; and (3) magnitude of intraoperative cerebral desaturation events (CDEs) in subjects undergoing arthroscopic shoulder surgery in the beach chair position, as well as whether (4) the length of surgery was an independent risk factor for intraoperative CDEs. METHODS: Regional cerebral tissue oxygen saturation (rSO2) was monitored intraoperatively using near-infrared spectroscopy on 51 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. Intraoperative decreases in rSO2 of 20% or greater were defined as CDEs. RESULTS: The incidence of intraoperative CDEs in our series was 18% (nine of 51). Among the patients demonstrating CDE (n = 9), the mean time to onset of initial CDE was 18 minutes 38 seconds postinduction. Of those experiencing CDEs, the mean maximal decrease in rSO2 was 32% from preoperative baseline per patient. Additionally, the mean number of separate CDE instances was 1.89 in this patient population with an average duration of 3 minutes 3 seconds per instance. There was no statistically significant difference (p = 0.202) between patients demonstrating CDEs and those without in regard to length of surgery (95 versus 88 minutes). CONCLUSIONS: The degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with near-infrared spectroscopy allows prompt identification and treatment of decreased cerebral perfusion. We believe protocols aimed at detecting and reversing CDE may improve patient safety.

Cerebral desaturation events during shoulder arthroscopy in the beach chair position: patient risk factors and neurocognitive effects.

BACKGROUND: Patients undergoing shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications due to cerebral ischemia. We sought to define the incidence, patient risk factors, and clinical sequelae of intraoperative cerebral desaturation events. METHODS: Regional cerebral tissue oxygen saturation (rSO2) was monitored intra-operatively using near-infrared spectroscopy (NIRS) on 50 consecutive patients. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was administered to each patient pre- and postoperatively. Intra-operative decreases in rSO2 of 20% or greater were defined as cerebral desaturation events (CDE). The association between intraoperative CDE and postoperative cognitive decline was assessed. RESULTS: The incidence of intraoperative CDE in our series was 18% (9/50). Increased body mass index (BMI) was found to have a statistically significant association with intraoperative CDE (mean BMI 37.32 vs 28.59, P < .0001). There was no statistical significance in pre- vs postoperative RBANS either in composite scores or any of the sub-indices in either group. CONCLUSION: The degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with NIRS allows prompt identification and treatment of decreased cerebral perfusion decreasing the risk of this event. Increased BMI was found to be a statistically significant patient risk factor for the development of intra-operative CDE. The transient intra-operative CDEs were not associated with postoperative cognitive dysfunction in our patient series. We believe protocols aimed at detecting and reversing CDE minimize the risk of neurocognitive dysfunction and improve patient safety.

Posttraumatic elbow arthritis in the young adult: evaluation and management.

Degenerative joint disease following trauma to the elbow is difficult to manage in any patient. However, this condition becomes substantially more challenging in the young, active population. Increased activity demands and limited functional capacity of total elbow arthroplasty mean that joint arthroplasty should be regarded as a salvage procedure. The primary goal of treatment is to restore a pain-free or minimally painful functional joint while preserving future surgical options. This requires accurate assessment of the primary patient complaint, be it terminal pain and stiffness or pain along the entire arc of motion. Patients who report stiffness and pain at terminal motion may benefit from arthroscopic or open osteocapsular débridement. Those with advanced degenerative changes and pain throughout the entire arc of motion may require joint resurfacing with interposition arthroplasty, partial joint arthroplasty, or total joint arthroplasty.

Glenoid bone loss in primary total shoulder arthroplasty: evaluation and management.

Glenohumeral osteoarthritis is the most common reason for shoulder replacement. Total shoulder arthroplasty provides reliable pain relief and restoration of function, with implant survivorship reported at 85% at 15 years. Glenoid component wear and aseptic loosening are among the most common reasons for revision. Glenoid wear characteristics have been correlated with, among other things, the degree of anatomic glenoid version correction. Anatomic glenoid reconstruction is particularly challenging in the presence of glenoid bone deficiency. Walch classified glenoid morphology into five types: type A, centered, without posterior subluxation but with minor erosion (A1) or major erosion (A2); type B, posteriorly subluxated (B1) or posteriorly subluxated with posterior glenoid erosion (B2); and type C, excessive glenoid retroversion. The type A glenoid represents only 59% of patients; thus, the need to address glenoid deformity is common. Methods of correction include asymmetric reaming of the anterior glenoid, bone grafting of the posterior glenoid, and implanting a specialized glenoid component with posterior augmentation. In many cases of type C or hypoplastic glenoid, the humerus is concentrically reduced in the deficient glenoid and glenoid deformity may not need to be corrected. Severely hypoplastic glenoid may require the use of bone-sparing glenoid components or reverse total shoulder arthroplasty.

A Comparison of Central Screw versus Post for Glenoid Baseplate Fixation in Reverse Shoulder Arthroplasty Using a Lateralized Glenoid Design.

The purpose of this study was to compare the short-term clinical and radiographic outcomes of a lateralized glenoid construct with either a central screw or post. Methods: A multicenter retrospective study was conducted of reverse shoulder arthroplasties (RSAs) with minimum 2-year clinical followup. All RSAs implanted had a 135° neck shaft angle (NSA) and a modular circular baseplate. The patients were divided into two cohorts based on the type of central fixation for their glenoid baseplates (central post (CP) vs. central screw (CS)). The clinical outcomes, rates of revisions, and available radiographs were evaluated. Results: In total, 212 patients met the study criteria. Postoperatively, both groups improved over their preoperative baseline. There were no significant differences between the cohorts in any PROs at 2 years postoperatively. No findings of gross loosening were identified in either cohort. Implant survival was 98.6% at 2 years. Conclusions: When using a lateralized glenoid implant with a 135° NSA inlay humeral component, both central post and central screw baseplate fixation provide good clinical outcomes, survivorship, and improvements in ROM at 2 years. There is no difference in loosening or revision rates between the types of baseplate fixation at a minimum of 2 years postoperatively.

Patient reported outcomes and ranges of motion after reverse total shoulder arthroplasty with and without subscapularis repair.

Background: In performing reverse total shoulder arthroplasty (rTSA), the role of repairing the subscapularis has been debated. Our objective was to determine the effect of subscapularis repair following rTSA on postoperative shoulder ranges of motion and patient reported outcome scores (PROs). Methods: A prospective registry was reviewed to establish a cohort of primary rTSA patients with a 135-degree humeral implant, with a minimum of 2 years of follow-up. Variables collected included demographics, subscapularis repair information, diagnosis, glenosphere size, and glenoid lateralization information. Outcomes collected were range of motion measurements, subscapularis strength, and multiple generic and shoulder PROs. Multivariable linear regression models were created to predict these 2-year outcomes. Results: The 143-patient cohort had a mean age of 69 years with 68% of patients undergoing subscapularis repair. After adjustment in the multivariable models, whether the subscapularis was repaired did not significantly predict a 2-year forward elevation, external rotation, internal rotation, subscapularis strength, Western Ontario Osteoarthritis of the Shoulder score, VR-12 scores, Constant Score, or American Shoulder and Elbow Surgeons Shoulder Scores. Increased glenoid lateralization significantly predicted greater internal rotation, higher VR-12 physical score, and higher Constant Score. There were no dislocations in either group. Conclusions: After adjusting for patient and implant factors, subscapularis repair was not associated with a 2-year postoperative range of motion, strength, or any PROs suggesting that repairing the subscapularis may not affect functional outcome. Increased glenoid lateralization through the baseplate and glenosphere independently predicted better internal rotation, VR-12 physical score, and Constant Scores indicating a benefit to lateralization during rTSA.

Intramedullary Fixation for Proximal Humeral Fractures.

Proximal humeral fractures are a commonly encountered injury; however, no consensus has been reached for the ideal treatment. Current surgical fixation options include plate, plate with fibular strut allograft, intramedullary fixation, pinning, suture constructs, and external fixation. Each of these options possesses distinct advantages and disadvantages. With the evolution of implant design, a greater understanding of the mechanisms of failure of fixation, and the ability to preserve fracture biology, the management of proximal humeral fractures with intramedullary fixation has become an accepted treatment option. From a biomechanical perspective, intramedullary fixation may have advantages over laterally based fixation, in particular with fractures associated with significant calcar comminution. The ability to insert the implant from a superior starting point may help preserve vascular supply to the humeral head and tuberosities. With reported outcomes comparable with the aforementioned techniques and an evolving understanding of fracture characteristics and failures of fixation, intramedullary fixation represents an alternative treatment option for proximal humeral fractures with specific fixation and biologic advantages.

Operative duration-based learning period analysis for reverse and total shoulder arthroplasty: A multicenter study.

BACKGROUND: A surgical learning period may be quantified after which operative duration is significantly reduced. We sought to retrospectively quantify and compare surgeon's learning experience for total shoulder arthroplasty and reverse shoulder arthroplasty. METHODS: We reviewed 2055 shoulder arthroplasty cases from 2011 to 2015 for four early-career and four later-career fellowship-trained shoulder surgeons from four institutions. We plotted consecutive case number versus operative time for each surgeon separately for total shoulder arthroplasty or reverse shoulder arthroplasty. Two-step regression approach was used to determine a plateau point or end of the learning period. Additionally, the mean annual volume of reverse shoulder arthroplasty and total shoulder arthroplasty for each surgeon was plotted against mean surgery duration. Early- and later-career surgeons were compared with regression analysis. RESULTS: Early-career surgeons demonstrated a significant decrease in operative time with increasing annual case volume for reverse shoulder arthroplasty (p = 0.01; m = -1.1) and total shoulder arthroplasty (p = 0.02; m = -0.8). Three of four early-career surgeons reached a plateau point for either reverse shoulder arthroplasty or total shoulder arthroplasty between 12 and 86 cases. CONCLUSION: For only early-career surgeons, higher case volume yields decreased operative duration, with improvement more pronounced for reverse shoulder arthroplasty compared to total shoulder arthroplasty. Though the learning period varies, it may be fewer than 90 cases.

Anatomic evaluation of radiographic landmarks for accurate straight antegrade intramedullary nail placement in the humerus.

BACKGROUND: Neurovascular insult, nonunion, and iatrogenic rotator cuff injury are concerns when using an intramedullary nail (IMN) for proximal humerus fracture. The purpose of this study was to identify a reproducible starting point and intraoperative imaging for nail insertion optimizing nail depth, tuberosity screw position, and protecting the axillary nerve and rotator cuff insertion. Our hypothesis was that a more medialized starting point would protect soft tissue structures and improve locking screw positioning. METHODS: Ten fresh-frozen cadavers underwent antegrade IMN with Grashey and modified lateral "precipice" view imaging. A guidewire was positioned medial to the coracoacromial ligament (CAL) in 5 cadavers and lateral to the CAL in 5. Distances from the nail entry point to anatomic landmarks were measured. Anatomic and histologic evaluations were performed, characterizing the nail perforation zone. Radiographs were compared between groups. RESULTS: The medial CAL group had a greater distance of screw fixation to the axillary nerve, a shorter distance of greater tuberosity (GT) screw fixation at the rotator cuff insertion on the infraspinatus and teres minor tubercles, and greater screw spread with improved lesser tuberosity capture. Two laterally placed implants violated the rotator cuff tendon. Imaging demonstrated that the ideal starting pin position was medial to the articular margin at a distance equal to the width of the rotator cuff insertion footprint. CONCLUSIONS: Medial placement optimized fixation of the GT, avoided violation of the rotator cuff tendon and footprint, and was associated with an increased distance of proximal locking screw to the axillary nerve.