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Background: Although typically favorable in outcome, anatomic total shoulder arthroplasty (aTSA) can require long-term revision. The most common cause for revision is glenoid loosening, which may result from eccentric cyclic forces and joint translations. "Rocking" of the glenoid component may be exacerbated by the joint geometry, such as glenoid inclination and version. Restoration of premorbid glenoid inclination may be preferable, although laboratory and computational models indicate that both superior inclination and inferior inclination have benefits. This discrepancy may arise because previous studies were limited by a lack of physiological conditions to test inclination. Therefore, a cadaveric shoulder simulator with 3-dimensional human motion was used to study joint contact and muscle forces with isolated changes in glenoid inclination., Methods: Eight human cadaveric shoulders were tested before and after aTSA. Scapular-plane abduction kinematics from human subjects were used to drive a cadaveric shoulder simulator with 3-dimensional scapulothoracic and glenohumeral motion. Glenoid inclination was varied from -10° to +20°, whereas compressive, superior-inferior shear, and anterior-posterior shear forces were collected with a 6-df load cell during motion. Outputs also included muscle forces of the deltoid and rotator cuff. Data were evaluated with statistical parametric mapping repeated-measures analysis of variance and t tests., Results: Inferior glenoid inclination (-10°) reduced both compressive and superior-inferior shear forces vs. neutral 0° inclination by up to 40%, and even more when compared with superior inclination (P < .001). Superior inclinations (+10° and +20°) tended to increase deltoid and rotator cuff forces vs. neutral 0° inclination or inferior inclination, on the order of 20%-40% (P ≤ .045). All force metrics except anterior-posterior shear were lowest for inferior inclination. Most aTSA muscle forces for neutral 0° inclination were not significantly different from native shoulders and decreased 45% and 15% in the posterior deltoid and supraspinatus, respectively (P ≤ .003). Joint translations were similar to prior reports in aTSA patients and did not differ between any inclinations or compared with native shoulders. Joint reaction forces were similar to those observed in human subjects with instrumented aTSA implants, providing confidence in the relative magnitude of our results., Conclusions: Inferior inclination reduces overall forces in the shoulder. Superior inclinations increase the muscle effort required for the shoulder to achieve similar motion, thus increasing the forces exerted on the glenoid component. These results suggest that a preference toward aTSA glenoid components in inferior inclination may reduce the likelihood of glenoid loosening by reducing excessive muscle and joint contact forces., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Introduction: Quantifying patient outcomes is integral in orthopaedic practice, and patient-reported outcome measures (PROMs) assist with this goal and assist clinicians in assessing subjective outcomes (pain, satisfaction, etc.). This study seeks to identify the most highly used PROMs in the shoulder literature and analyze their usage trends., Methods: PubMed was queried for all shoulder-based articles published in eight selected journals from 2007 to 2017. Articles were assessed for PROM usage, surgical approach, surgical procedure, and disease pathology. Frequency analyses identified the most used PROMs overall, and for each approach, procedure, and pathology. Last, usage trends, question number, validation, and clinician dependence of PROMs with ≥20 uses were analyzed., Results: In total, 1,740 of 2,462 articles (71%) used 105 unique PROMs 4,394 times during the study. PROM usage increased 18%, and the use of multiple PROMs increased by 20%. PROMs with a clinician component increased 21% slower than the baseline. Twenty-two PROMs (17%) had >20 uses, with the most used PROMs being the Constant-Murley Score (783), American Shoulder and Elbow Surgeons Shoulder Score (731), Visual Analog Scale (685), Simple Shoulder Test (372), and the University of California, Los Angeles, Shoulder Rating Scale (274). PROMs demonstrating the greatest usage increase were the EuroQol 5-Dimensions Questionnaire (1,282%), Shoulder Pain and Disability Index (638%), Western Ontario Rotator Cuff Index (632%), Western Ontario Osteoarthritis of the Shoulder Index (582%), and Oxford Shoulder Score (462%)-all without a clinician component., Discussion: PROM usage is increasing, often with multiple PROMs being used to evaluate patient outcomes. PROMs without a clinician component are growing at higher rates than their clinician-dependent counterparts, highlighting an emphasis on patient reporting of outcomes. This study suggests that the American Shoulder and Elbow Surgeons Shoulder Score, Oxford Shoulder Score, Visual Analog Scales-all without a mandatory clinician component and high levels of use-will be the most highly used PROMs moving forward to assess shoulder function.

Background: Muscle volume is important in shoulder function. It can be used to estimate shoulder muscle balance in health, pathology, and repair and is indicative of strength based on muscle size. Although prior studies have shown that muscle area on two-dimensional (2-D) images correlates with three-dimensional (3-D) muscle volume, they have not provided equations to predict muscle volume from imaging nor validation of the measurements., Questions/purposes: We wished to create an algorithm that quickly, accurately, and reliably estimates the volume of the shoulder muscles using cross-sectional area on MR images with low error. Specifically, we wished to (1) determine which MR imaging planes provide the highest correlation between shoulder muscle cross-sectional area and volume; (2) derive equations to predict muscle volume from cross-sectional area and validate their predictive capability; and (3) quantify the reliability of muscle cross-sectional area measurement., Methods: Three-dimensional MRI was performed on 10 cadaver shoulders, with sample size chosen for comparison to prior studies of shoulder muscle volume and in consideration of the cost of comprehensive analysis, followed by dissection for muscle volume measurement via water displacement. From each MR series, 3-D models of the rotator cuff and deltoid muscles were generated, and 2-D slices of these muscle models were selected at defined anatomic landmarks. Linear regression equations were generated to predict muscle volume at the plane(s) with the highest correlation between volume and area and for planes identified in prior studies of muscle volume and area. Volume predictions from MR scans of six different cadaver shoulders were also made, after which they were dissected to quantify muscle volume. This validation population allowed the calculation of the predictive error compared with actual muscle volume. Finally, reliability of measuring muscle areas on MR images was calculated using intraclass correlation coefficients for inter-rater reliability, as measured between two observers at a single time point., Results: The rotator cuff planes with the highest correlation between volume and area were the sum of the glenoid face and the midpoint of the scapula, and for the deltoid, it was the transverse plane at the top of the greater tuberosity. Water and digital muscle volumes were highly correlated (r ≥ 0.993, error < 4%), and muscle areas correlated highly with volumes (r ≥ 0.992, error < 2%). All correlations had p < 0.001. Muscle volume was predicted with low mean error (< 10%). All intraclass correlation coefficients were > 0.925, suggesting high inter-rater reliability in determining muscle areas from MR images., Conclusion: Deltoid and rotator cuff muscle cross-sectional areas can be reliably measured on MRI and predict muscle volumes with low error., Clinical Relevance: Using simple linear equations, 2-D muscle area measurements from common clinical image analysis software can be used to estimate 3-D muscle volumes from MR image data. Future studies should determine if these muscle volume estimations can be used in the evaluation of patient function, changes in shoulder health, and in populations with muscle atrophy. Additionally, these muscle volume estimation techniques can be used as inputs to musculoskeletal models examining kinetics and kinematics of humans that rely on subject-specific muscle architecture.

Background: This study evaluated the psychometric properties of the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) instrument administered through computerized adaptive testing (CAT) compared with the traditional full-length Disabilities of the Arm, Shoulder and Hand (DASH)., Methods: The PROMIS PF CAT and the DASH were administered to 1759 patients seeking care for elbow conditions. This study used Rasch partial credit modeling to analyze the instruments with item fit, internal reliability, response category thresholds, dimensionality, local independence, gender differential item functioning, and floor and ceiling effects., Results: The PROMIS PF CAT and DASH had satisfactory item fit for all but 1 item on both measures. Internal reliabilities were high for both measures. Two items on the DASH and 4 items on the PF CAT showed nonordered category thresholds. Unidimensionality was adequate, and local independence was supported for both instruments. Gender bias was found for 4 items on the PF CAT and 12 items on the DASH. Both measures had adequate instrument targeting and satisfactory floor and ceiling effects., Conclusion: The PROMIS PF CAT and the DASH both showed sufficient unidimensionality, good item fit, and good local independence with the exception of high levels of gender item bias, particularly for the DASH. Further scale evaluation should address item bias and item response categories for these instruments. Overall, the PROMIS PF CAT is an effective outcome instrument to measure function in patients with elbow disorders that requires significantly fewer questions than the DASH., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: We developed two objective structured clinical examinations (OSCEs) to educate and evaluate trainees in the evaluation and management of shoulder and knee pain. Our objective was to examine the evidence for validity of these OSCEs., Methods: A multidisciplinary team of content experts developed checklists of exam maneuvers and criteria to guide rater observations. Content was proposed by faculty, supplemented by literature review, and finalized using a Delphi process. One faculty simulated the patient, another rated examinee performance. Two faculty independently rated a portion of cases. Percent agreement was calculated and Cohen's kappa corrected for chance agreement on binary outcomes. Examinees' self-assessment was explored by written surveys. Responses were stratified into 3 categories and compared with similarly stratified OSCE scores using Pearson's coefficient., Results: A multi-disciplinary cohort of 69 examinees participated. Examinees correctly identified rotator cuff and meniscal disease 88% and 89% of the time, respectively. Inter-rater agreement was moderate for the knee (87%; k = 0.61) and near perfect for the shoulder (97%; k = 0.88). No correlation between stratified self-assessment and OSCE scores were found for either shoulder (0.02) or knee (-0.07)., Conclusions: Validity evidence supports the continuing use of these OSCEs in educational programs addressing the evaluation and management of shoulder and knee pain. Evidence for validity includes the systematic development of content, rigorous control of the response process, and demonstration of acceptable interrater agreement. Lack of correlation with self-assessment suggests that these OSCEs measure a construct different from learners' self-confidence.

Background: The Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Computerized Adaptive Test (PF CAT) is a newly developed patient-reported outcome instrument designed by the National Institutes of Health to measure generalized physical function. However, the measurement properties of the PF CAT have not been compared with established shoulder-specific patient-reported outcomes., Methods: Patients with clinical diagnosis of rotator cuff disease completed the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST), and PF CAT. Responses to each of the 3 instruments were statistically analyzed with a Rasch partial credit model. Associations between instruments, convergent validity, item and person reliability, ceiling and floor effects, dimensionality, and survey length were determined., Results: Responses from 187 patients were analyzed. The PF CAT required fewer questions than the ASES or SST (PF CAT, 4.3; ASES, 11; SST, 12). Correlation between all instruments was moderately high. Item reliability was excellent for all instruments, but person reliability of the PF CAT was superior (0.93, excellent) to the SST (0.71, moderate) and ASES (0.48, fair). Ceiling effects were similar among all instruments (PF CAT, 0.53%; SST, 6.1%; ASES, 2.3%). Floor effects were found in 21% of respondents to the SST but in only 3.2% of PF CAT and 2.3% of ASES respondents., Conclusion: The measurement properties of the PROMIS PF CAT compared favorably with the ASES and SST despite requiring fewer questions to complete. The PROMIS PF CAT had improved person reliability compared with the ASES score and fewer floor effects compared with the SST., (Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Subpectoral biceps tenodesis has been reliably used to treat a variety of biceps tendon pathologies. Interference screws have been shown to have superior biomechanical properties compared to suture anchors; although, only single anchor constructs have been evaluated in the subpectoral region. The purpose of this study was to compare interference screw fixation with a suture anchor construct, using 2 anchors for a subpectoral tenodesis., Methods: A subpectoral biceps tenodesis was performed using either an interference screw (8 × 12 mm; Arthrex) or 2 suture anchors (Mitek G4) with #2 FiberWire (Arthrex) in a Krackow and Bunnell configuration in seven pairs of human cadavers. The humerus was inverted in an Instron and the biceps tendon was loaded vertically. Displacement driven cyclic loading was performed followed by failure loading., Results: Suture anchor constructs had lower stiffness upon initial loading (P = .013). After 100 cycles, the stiffness of the suture anchor construct "softened" (decreased 9%, P < .001), whereas the screw construct was unchanged (0.4%, P = .078). Suture anchors had significantly higher ultimate failure strain than the screws (P = .003), but ultimate failure loads were similar between constructs: 280 ± 95 N (screw) vs 310 ± 91 N (anchors) (P = .438)., Conclusion: The interference screw was significantly stiffer than the suture anchor construct. Ultimate failure loads were similar between constructs, unlike previous reports indicating interference screws had higher ultimate failure loads compared to suture anchors. Neither construct was superior with regards to stress; although, suture anchors could withstand greater elongation prior to failure., (Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Internal rotation in adduction is often limited after reverse total shoulder arthroplasty (rTSA), but the origins of this functional deficit are unclear. Few studies have directly compared individuals who can and cannot perform internal rotation in adduction. Little data on underlying 3D humerothoracic, scapulothoracic, and glenohumeral joint relationships in these patients are available. Individuals >1-year postoperative to rTSA were imaged with biplane fluoroscopy in resting neutral and internal rotation in adduction poses. Subjects could either perform internal rotation in adduction with their hand at T12 or higher (high, N = 7), or below the hip pocket (low, N = 8). Demographics, the American Shoulder and Elbow Surgeons score, Simple Shoulder Test, and scapular notching grade were recorded. Joint orientation angles were derived from model-based markerless tracking of the scapula and humerus relative to the torso. The 3D implant models were aligned to preoperative computed tomography models to evaluate bone-implant impingement. The Simple Shoulder Test was highest in the high group (11 ± 1 vs. 9 ± 2, P =.019). Two subjects per group had scapular notching (grades 1 and 2), and 3 high group and 4 low group subjects had impingement below the glenoid. In the neutral pose, the scapula had 7° more upward rotation in the high group (P =.100), and the low group demonstrated 9° more posterior tilt (P =.017) and 14° more glenohumeral elevation (P =.047). In the internal rotation pose, axial rotation was >45° higher in the high group (P ≤.008) and the low group again had 11° more glenohumeral elevation (P =.058). Large rotational differences within subject groups arose from a combination of differences in the resting neutral and maximum internal rotation in adduction poses, not only the terminal arm position. Individuals who were able to perform high internal rotation in adduction after rTSA demonstrated differences in joint orientation and anatomic biases versus patients with low internal rotation. The high rotation group had 7° more resting scapular upward rotation and used a 15°-30° change in scapular tilt to perform internal rotation in adduction versus patients in the low group. The combination of altered resting scapular posture and restricted scapulothoracic range of motion could prohibit glenohumeral rotation required to reach internal rotation in adduction. In addition, inter-patient variation in humeral torsion may contribute substantially to postoperative internal rotation differences. These data point toward modifiable implant design and placement factors, as well as foci for physical therapy to strengthen and mobilize the scapula and glenohumeral joint in response to rTSA surgery. [ABSTRACT FROM AUTHOR]

Background: Reverse total shoulder arthroplasty (rTSA) typically restores active arm elevation. Prior studies in patients with rTSA during tasks that load the arm had limitations that obscured underlying three-dimensional (3D) kinematic changes and the origins of motion restrictions. Understanding the scapulothoracic and glenohumeral contributions to loaded arm elevation will uncover where functional deficits arise and inform strategies to improve rTSA outcomes.Questions/purposes: In a cohort of patients who had undergone rTSA and a control cohort, we asked: (1) Is there a difference in maximum humerothoracic elevation when scapular plane elevation (scaption) is performed with and without a handheld weight? (2) Is maximum humerothoracic elevation related to factors like demographics, patient-reported outcome scores, isometric strength, and scapular notching (in the rTSA group only)? (3) Are there differences in underlying 3D scapulothoracic and glenohumeral motion during scaption with and without a handheld weight?Methods: Ten participants who underwent rTSA (six males, four females; age 73 ± 8 years) were recruited at follow-up visits if they were more than 1 year postoperative (24 ± 11 months), had a BMI less than 35 kg/m 2 (29 ± 4 kg/m 2 ), had a preoperative CT scan, and could perform pain-free scaption. Data from 10 participants with a nonpathologic shoulder, collected previously (five males, five females; age 58 ± 7 years; BMI 26 ± 3 kg/m 2 ), were a control group with the same high-resolution quantitative metrics available for comparison. Participants in both groups performed scaption with and without a 2.2-kg handheld weight while being imaged with biplane fluoroscopy. Maximum humerothoracic elevation and 3D scapulothoracic and glenohumeral kinematics across their achievable ROM were collected via dynamic imaging. In the same session the American Shoulder and Elbow Surgeons (ASES) score, the Simple Shoulder Test (SST), and isometric strength were collected. Data were compared between weighted and unweighted scaption using paired t-tests and linear mixed-effects models.Results: When compared with unweighted scaption, maximum humerothoracic elevation decreased during weighted scaption for patients who underwent rTSA (-25° ± 30°; p = 0.03) but not for the control group (-2° ± 5°; p = 0.35). In the rTSA group, maximum elevation correlated with the ASES score (r = 0.72; p = 0.02), and weighted scaption correlated with BMI (r = 0.72; p = 0.02) and the SST (r = 0.76; p = 0.01). Scapular notching was observed in three patients after rTSA (Grades 1 and 2). Four of 10 patients who underwent rTSA performed weighted scaption to less than 90° humerothoracic elevation using almost exclusively scapulothoracic motion, with little glenohumeral contribution. This manifested as changes in the estimated coefficient representing mean differences in slopes in the humerothoracic plane of elevation (-12° ± 2°; p < 0.001) and true axial rotation (-16° ± 2°; p < 0.001), scapulothoracic upward rotation (7° ± 1°; p < 0.001), and glenohumeral elevation (-12° ± 1°; p < 0.001), plane of elevation (-8° ± 3°; p = 0.002), and true axial rotation (-11° ± 2°; p < 0.001). The control group demonstrated small differences between scaption activities (< |2°|), but a 10° increase in humerothoracic and glenohumeral axial rotation (both p < 0.001).Conclusion: After rTSA surgery, maximum humerothoracic elevation decreased during weighted scaption by up to 88° compared with unweighted scaption, whereas 4 of 10 patients could not achieve more than 90° of elevation. These patients exhibited appreciable changes in nearly all scapulothoracic and glenohumeral degrees of freedom, most notably a near absence of glenohumeral elevation during weighted scaption. Patients with rTSA have unique strategies to elevate their arms, often with decreased glenohumeral motion and resultant compensation in scapulothoracic motion. In contrast, the control group showed few differences when lifting a handheld weight.Clinical Relevance: Functional deficiency in activities that load the shoulder after rTSA surgery can affect patient independence, and they may be prevalent but not captured in clinical studies. Pre- or postoperative rehabilitation to strengthen scapular stabilizers and the deltoid should be evaluated against postoperative shoulder function. Further study is required to determine the etiology of deficient glenohumeral motion after rTSA, and the most effective surgical and/or rehabilitative strategies to restore deficient glenohumeral motion after rTSA. [ABSTRACT FROM AUTHOR]

Background: Computer assisted planning without patient specific instrumentation may be utilized to guide reverse total shoulder arthroplasty baseplate placement. The purpose of this study was to determine the difference between planned and achieved inclination and retroversion correction with three-dimensional preoperative computer assisted planning in reverse total shoulder arthroplasty without patient specific instrumentation with bone grafting for severe glenoid erosion. Methods: Preoperative three-dimensional computer assisted planning without patient specific instrumentation was performed on 15 patients undergoing primary reverse total shoulder arthroplasty with glenoid bone grafting for severe glenoid erosion. On preoperative and immediate postoperative computed tomography slices, two-dimensional retroversion and inclination were measured. Preoperative three-dimensional baseline retroversion and inclination and planned postoperative three-dimensional retroversion and inclination were measured. Planned and achieved version and inclination changes were compared. Results: The planned and achieved retroversion corrections were 18° and 12°, respectively (p < 0.001). The planned and achieved inclination corrections were 11° and 11°, respectively (p = 0.803). Conclusions: Three-dimensional computer assisted planning without patient specific instrumentation in the setting of reverse total shoulder arthroplasty with severe glenoid erosion requiring bone grafting can accurately guide baseplate placement. All cases in which failure to correct retroversion or inclination within 10° of planning occurred in patients with severe erosion (B3 or E3 glenoids), therefore patient specific guides may be warranted in these cases to improve accuracy of implantation. Level of evidence: Level IV, retrospective case series. [ABSTRACT FROM AUTHOR]

Restoration of muscular strength is predicated on restoration of muscle length. The purpose of this study was to describe infraspinatus and deltoid length preoperative to reverse total shoulder arthroplasty (RTSA) to guide distalization and lateralization to restore preoperative muscle length. This was a retrospective radiographic study. We measured the infraspinatus length on preoperative computed tomographic images and the deltoid length on preoperative radiographs. For all measurements, reliability was first established by comparing measurements between 2 observers, and intraclass correlation coefficients (ICCs) were calculated. We then calculated descriptive statistics for these muscle lengths and developed a formula to predict these muscle lengths from patient demographics. We measured infraspinatus length in 97 patients and deltoid length in 108 patients. Inter-rater reliability was excellent, with all ICCs >0.886. The mean infraspinatus length was 15.5 cm (standard deviation 1.3) and ranged from 12.6-18.9 cm, whereas the deltoid length was 16.2±1.7 cm and ranged from 12.5-20.2 cm. Both infraspinatus (r = 0.775, P <.001) and deltoid length (r = 0.717, P <.001) were highly correlated with patient height but did not differ between diagnoses. Formulae developed through linear regression allowed prediction of muscle length to within 1 cm in 78% and within 2 cm in 100% for the infraspinatus and 60% and 88% for the deltoid. Deltoid and infraspinatus length are variable but highly correlated with patient height. To maintain tension, 2 mm of lateralization and distalization should be added for every 6 inches (∼15 cm) of height above average for a Grammont-style RTSA. [ABSTRACT FROM AUTHOR]

Variation in the shape of the glenoid and periarticular anatomy of the scapula has been associated with shoulder pathology. The goal of this study was to identify the modes of shape variation of periarticular scapular anatomy in relation to the glenoid in nonpathologic shoulders. Computed tomography scans of 31 cadaveric scapulae, verified to be free of pathology, were three‐dimensionally reconstructed. Statistical shape modeling and principal component analysis identified the modes of shape variation across the population. Corresponding linear and angular measurements quantified the morphometric variance identified by the modes. Linear measures were normalized to the radius of the inferior glenoid to account for differences in the scaling of the bones. Five modes captured 89.7% of total shape variation of the glenoid and periarticular anatomy. Apart from size differences (mode 1: 33.0%), acromial anatomy accounted for the largest variation (mode 2: 32.0%). Further modes described variation in glenoid inclination (mode 3: 11.8%), coracoid orientation and size (mode 4: 9.0%), and variation in coracoacromial (CA) morphology (mode 5: 3.1%). The average scapula had a mean acromial tilt of 49 ± 7°, scapular spine angle of 61 ± 6°, the glenoid inclination of 84 ± 4°, coracoid deviation angle of 26 ± 4°, coracoid length of 3.7 ± 0.3 glenoid radii, and a CA base length of 5.6 ± 0.5 radii. In this study, the identified shape modes explain almost all of the variance in scapular anatomy. The acromion exhibited the highest variance of all periarticular anatomic structures of the scapula in relation to the glenoid, which may play a role in many shoulder pathologies. [ABSTRACT FROM AUTHOR]

Background: Humeral bone loss is commonly encountered during revision shoulder arthroplasty and anticipating humeral bone defects can help the revision surgeon make appropriate plans to achieve adequate fixation and stability. No validated classification system exists to characterize humeral bone loss in the setting of revision shoulder arthroplasty.Questions/purposes: The purposes of this study were (1) to create a classification system for humeral bone loss in revision shoulder arthroplasty; (2) to determine the classification system's reliability; and (3) to determine whether humeral bone loss type is associated with intraoperative humeral-related reconstruction characteristics.Methods: This was a comparative retrospective radiographic study. First, six surgeons from five centers collaborated to create a classification by consensus. Second, two surgeons from two other centers who had fellowship training in shoulder and elbow surgery, who were blinded to each other's grades and all patient details other than plain radiographs, and who were not involved in creation of the system, classified true AP, AP, and lateral (axillary and/or scapular-Y) radiographs from 108 revision (413 radiographs) from one center that were performed between November 15, 2006, and January 4, 2018. Interobserver reliability was calculated by comparing those two reviews and determining Cohen's κ. In addition, one reviewer repeated his assessments twice, 4 months apart, to determine intraobserver reliability using Cohen's κ. Third, we performed a retrospective chart study of these same revisions to determine intraoperative humeral-related reconstruction characteristics such as the use of greater tuberosity fixation, stem length, humeral bone grafting, and the use of proximal humeral replacement or total humeral replacement; at the center where these revisions were performed during that timespan, no attempt to classify bone loss was made. During that period, the general indications for greater tuberosity fixation included the absence of a stable osseous connection between the greater tuberosity and the shaft of the humerus with a tuberosity amendable to repair; the general indications for use of longer stems were inability to obtain a minimum of two cortical widths of overlap between the implant and the humeral diaphysis and/or loss of the greater tuberosity; and the general indications for proximal and total humeral replacement were bone loss that was felt to be too severe to allow reconstruction with allograft.Results: The classification system consists of three types of humeral bone loss: Type 1 is loss of the epiphysis with subtypes for loss of the calcar and loss of the greater tuberosity; Type 2 is loss of the metadiaphysis above the deltoid attachment with a subtype for cortical thinning; and Type 3 is bone loss extending below the deltoid attachment with a subtype for cortical thinning. We studied 108 revisions: 38 (35%) without bone loss, 34 (31%) Type 1, 27 (25%) Type 2, and nine (8%) Type 3. For reliability, interrater κ was 0.545 and in 71% (77 of 108) of revisions, the two raters agreed on a numeric type. Intrarater κ was 0.615 and in 77% (83 of 108) of revisions, the rater agreed with himself as to the numeric type. Stem length increased with class type (Type 1 median [range] 130 [70-210], Type 2 150 [70-210], Type 3 190 [70-240], p = 0.005). Most greater tuberosity fixation for intraoperative fracture was in Types 1 and 2 (13 of 18 compared with the five of 18 of greater tuberosity fixation that was within Types 0 and 3, p = 0.043). Most bone grafting was in Types 2 and 3 (eight of 13 compared with five of 13 of bone grafting was in Types 0 and 1, p = 0.044). Most proximal humeral and total humeral replacements were in Type 3 (three of four compared with one of four, p < 0.001).Conclusions: We developed the Proximal Humeral Arthroplasty Revision Osseous inSufficiency (PHAROS) system, which has adequate, if imperfect, reliability to classify humeral bone loss in the setting of revision shoulder arthroplasty. This classification system may be useful to anticipate the complexity of humeral reconstruction. Further validation incorporating advanced imaging and further evaluators will be necessary.Level Of Evidence: Level III, diagnostic study. [ABSTRACT FROM AUTHOR]

Shoulder arthroplasty has advanced considerably in recent decades, but the most recently published long-term outcomes continue to have unacceptably high failure rates, especially in young patients. However, there are several future frontiers that offer the promise of improved implant longevity and function including advances in surgical approach, such as subscapularis-sparing approaches and computer-assisted surgical planning; advances in humeral component fixation, such as stemless, short-stem, and convertible implants; advances in bearing surfaces, such as pyrocarbon, ceramic, and metal-on-metal; and advances in glenoid component geometry and fixation, such as augmented components, in-growth pegs, and inlay glenoid components. [ABSTRACT FROM AUTHOR]

Background The best chance that a shoulder arthroplasty will restore motion and muscle balance across the glenohumeral joint is by closely replicating natural articular morphology. Defining the humeral osteotomy plane along clear landmarks at the anatomic neck is critical. We hypothesized that a new osteotomy, based on alternative landmarks on the anatomic neck, would restore 3-dimensional humeral head morphology more reliably than the traditional osteotomy. Methods The anatomic neck was digitized in 30 human cadaver shoulders and compared with its 3-dimensional computed tomography reconstruction. Two different osteotomy techniques were virtually performed: the traditional, following the anterosuperior anatomic neck; and a new technique, defined by the inferoanterior anatomic neck. The length-width difference and orientation (retroversion, inclination) of the resection area were compared between the techniques and with native anatomy. Results Length-width difference of the anterosuperior resection area was higher than in the inferoanterior osteotomy (6 ± 2 mm vs. 3 ± 1 mm; P  < .001). Retroversion of the anterosuperior resection plane was higher than the native head (50° ± 12° vs. 37° ± 11°; P  < .001), whereas retroversion after the inferoanterior osteotomy (32° ± 12°) did not differ from native ( P  = .057). Inclination differed after the anterosuperior osteotomy (129° ± 5°) and the inferoanterior osteotomy (127° ± 4°) compared with the native head (134° ± 4°; P  ≤ .001). Conclusion The inferoanterior referenced osteotomy generated a more circular resection area, matching the native humeral head retroversion more closely than in the anterosuperior technique. This study suggests that in shoulder arthroplasty, the humeral resection level should be referenced at the inferoanterior rather than the anterosuperior anatomic neck. Further studies should investigate the biomechanical effects of this alternative resection plane. [ABSTRACT FROM AUTHOR]

Background: Patient-reported outcome measures have increasingly accompanied objective examination findings in the evaluation of orthopaedic interventions. Our objective was to determine whether a validated measure of mental health (Short Form-36 Mental Component Summary [SF-36 MCS]) or measures of tear severity on magnetic resonance imaging were more strongly associated with self-assessed shoulder pain and function in patients with symptomatic full-thickness rotator cuff tears. Methods: One hundred and sixty-nine patients with full-thickness rotator cuff tears were prospectively enrolled. Patients completed the Short Form-36, visual analog scales for shoulder pain and function, the Simple Shoulder Test (SST), and the American Shoulder and Elbow Surgeons (ASES) instrument at the time of diagnosis. Shoulder magnetic resonance imaging examinations were reviewed to document the number of tendons involved, tear size, tendon retraction, and tear surface area. Age, sex, body mass index, number of medical comorbidities, smoking status, and Workers' Compensation status were recorded. Bivariate correlations and multivariate regression models were calculated to identify associations with baseline shoulder scores. Results: The SF-36 MCS had the strongest correlation with the visual analog scale for shoulder pain (Pearson correlation coefficient, -0.48; p < 0.001), the visual analog scale for shoulder function (Pearson correlation coefficient, -0.33; p < 0.001), the SST (Pearson correlation coefficient, 0.37; p < 0.001), and the ASES score (Pearson correlation coefficient, 0.51; p < 0.001). Tear severity only correlated with the visual analog scale for shoulder function; the Pearson correlation coefficient was 0.19 for tear size (p = 0.018), 0.18 for tendon retraction (p = 0.025), 0.18 for tear area (p = 0.022), and 0.20 for the number of tendons involved (p = 0.011). Tear severity did not correlate with other scores in bivariate correlations (all p > 0.05). In all multivariate models, the SF-36 MCS had the strongest association with the visual analog scale for shoulder pain, the visual analog scale for shoulder function, the SST, and the ASES score (all p < 0.001). Conclusions: Patient mental health may play an influential role in patient-reported pain and function in patients with full-thickness rotator cuff tears. Further studies are needed to determine its effect on the outcome of the treatment of rotator cuff disease. [ABSTRACT FROM AUTHOR]

Background: No clear recommendations exist regarding optimal humeral component version and deltoid tension in reverse total shoulder arthroplasty (TSA). Materials and methods: A biomechanical shoulder simulator tested humeral versions (0°, 10°, 20° retroversion) and implant thicknesses (−3, 0, +3 mm from baseline) after reverse TSA in human cadavers. Abduction and external rotation ranges of motion as well as abduction and dislocation forces were quantified for native arms and arms implanted with 9 combinations of humeral version and implant thickness. Results: Resting abduction angles increased significantly (up to 30°) after reverse TSA compared with native shoulders. With constant posterior cuff loads, native arms externally rotated 20°, whereas no external rotation occurred in implanted arms (20° net internal rotation). Humeral version did not affect rotational range of motion but did alter resting abduction. Abduction forces decreased 30% vs native shoulders but did not change when version or implant thickness was altered. Humeral center of rotation was shifted 17 mm medially and 12 mm inferiorly after implantation. The force required for lateral dislocation was 60% less than anterior and was not affected by implant thickness or version. Conclusion: Reverse TSA reduced abduction forces compared with native shoulders and resulted in limited external rotation and abduction ranges of motion. Because abduction force was reduced for all implants, the choice of humeral version and implant thickness should focus on range of motion. Lateral dislocation forces were less than anterior forces; thus, levering and inferior/posterior impingement may be a more probable basis for dislocation (laterally) than anteriorly directed forces. [ABSTRACT FROM AUTHOR]

Background: Interpretation of shoulder motion across studies has been complicated due to the use of numerous scapular coordinate systems in the literature. Currently, there are no simple means by which to compare scapular kinematics between coordinate system definitions when data from only one coordinate system is known.Research Question: How do scapular kinematics vary based on the choice of coordinate system and can average rotation matrices be used to accurately convert kinematics between scapular local coordinate systems?Methods: Average rotation matrices derived from anatomic landmarks of 51 cadaver scapulae (29 M/22 F; 59 ± 13 yrs; 26R/25 L; 171 ± 11 cm; 70 ± 19 kg; 23.7 ± 5.5 kg/m2) were generated between three common scapular coordinate systems. Absolute angle of rotation was used to determine if anatomical variability within the cadaver population influenced the matrices. To quantify the predictive capability to convert kinematics between the three coordinate systems, the average rotation matrices were applied to scapulothoracic motion data collected from 19 human subjects (10 M/9 F; 43 ± 17 yrs; 19R; 173 ± 9 cm; 71 ± 16 kg; 23.6 ± 4.5 kg/m2) using biplane fluoroscopy. Root mean squared error (RMSE) was used to compare kinematics from an original coordinate system to the kinematics expressed in each alternative coordinate system.Results: The choice of scapular coordinate system resulted in mean differences in scapulothoracic rotation of up to 23°, with overall different shapes and/or magnitudes of the curves. A single average rotation matrix between any two coordinate systems achieved accurate conversion of scapulothoracic kinematics to within 4° of RMSE of the known solution. The average rotation matrices were independent of sex, side, decomposition sequence, and motion.Significance: Scapulothoracic kinematic representations vary in shape and magnitude based solely on the choice of local coordinate system. The results of this study enhance interpretability and reproducibility in expressing scapulothoracic motion data between laboratories by providing a simple means to convert data between common coordinate systems. This is necessitated by the variety of available motion analysis techniques and their respective scapular landmark definitions. [ABSTRACT FROM AUTHOR]

Age affects gross shoulder range of motion (ROM), but biomechanical changes over a lifetime are typically only characterized for the humerothoracic joint. Suitable age-related baselines for the scapulothoracic and glenohumeral contributions to humerothoracic motion are needed to advance understanding of shoulder injuries and pathology. Notably, biomechanical comparisons between younger or older populations may obscure detected differences in underlying shoulder motion. Herein, biplane fluoroscopy and skin-marker motion analysis quantified humerothoracic, scapulothoracic, and glenohumeral motion during 3 static poses (resting neutral, internal rotation to L4-L5, and internal rotation to maximum reach) and 2 dynamic activities (scapular plane abduction and external rotation in adduction). Orientations during static poses and rotations during active ROM were compared between subjects <35 years and >45 years of age (N = 10 subjects per group). Numerous age-related kinematic differences were measured, ranging 5–22°, where variations in scapular orientation and motion were consistently observed. These disparities are on par with or exceed mean clinically important differences and standard error of measurement of clinical ROM, which indicates that high resolution techniques and appropriately matched controls are required to avoid confounding results of studies that investigate shoulder kinematics. Understanding these dissimilarities will help clinicians manage expectations and treatment protocols where indications and prevalence between age groups tend to differ. Where possible, it is advised to select age-matched control cohorts when studying the kinematics of shoulder injury, pathology, or surgical/physical therapy interventions to ensure clinically important differences are not overlooked. [ABSTRACT FROM AUTHOR]