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Cases: Two patients presented to different surgeons complaining of persistent shoulder pain after reverse total shoulder arthroplasty. Workups for fracture, instability, and periprosthetic infection were negative. Advanced imaging, nerve conduction studies, and diagnostic injections localized symptoms to the suprascapular nerve. Revision arthroplasty with removal of the offending screws improved pain in both patients. Conclusion: Suprascapular nerve irritation because of the malposition of baseplate screws in reverse total shoulder arthroplasty can be a source of postoperative pain. Removal of the offending screw without formal nerve exploration may result in symptomatic improvement. [ABSTRACT FROM AUTHOR]

There is no current standard by which culture specimens from revision shoulder arthroplasty should be handled, processed, cultured, and reported. Due to the relatively low numbers of cases multicenter study may provide information to form consensus recommendations. However, assimilation of multicenter data requires comparable methodologies. The objective of this study was to document and evaluate the extent of variability between surgeons and institutions. An 11-question survey was sent to 20 shoulder surgeons as part of the American Shoulder and Elbow Surgeons Periprosthetic Joint Infection Multicenter Workgroup. Questions addressed how samples are handled in the operating room by surgeons, processing of tissue samples and explants by laboratories, number of media, culture incubation durations, and culture reporting. Common practices regarding specimen handling and processing were identified including prolonged culture incubation times >13 days (94% of participants). However, substantial variation in handling of tissue and explant specimens, number and type of media used, and reporting of results were identified. The majority of surgeons reported using a sterile instrument to harvest each individual tissue specimen (10/17, 59%), more so than using any available instrument (4/17, 24%) or washing and re-using the same instrument (3/17, 18%). Half of the institutions require a time limit by which samples must be processed in the laboratory (8/16, 50%). Nine institutions (9/16, 56%) report cultures in a semiquantitative manner, while 7 (44%) report cultures in a binary fashion. Five institutions reported having performed a negative control study, and the rate of positive cultures ranged between 0% and 17%. The majority of positive cultures from the negative controls contained Cutibacterium (92%). Specimen handling, processing, culturing, and reporting varies widely between institutions. Due to the risk of false positives as demonstrated by negative control studies, surgeons should be cognizant of potential sources of contamination at the specimen handling level in the operating room and specimen processing level in the laboratory. Given the challenges in interpretation of positive cultures in revision shoulder arthroplasty, further studies are needed to determine whether assimilation of data across institutions is acceptable or whether a standard culturing methodology across institutions is necessary. Level of Evidence: V [ABSTRACT FROM AUTHOR]

Background: Use of 3-dimensional (3D) computed tomography (CT) preoperative planning and patient-specific instrumentation has been demonstrated to improve the accuracy of glenoid implant placement in total shoulder arthroplasty (TSA). The purpose of this study was to compare the accuracy of glenoid implant placement in primary TSA among different types of instrumentation used with the 3D CT preoperative planning.Methods: One hundred and seventy-three patients with end-stage glenohumeral arthritis were enrolled in 3 prospective studies evaluating patient-specific instrumentation and 3D preoperative planning. All patients underwent preoperative 3D CT planning to determine optimal glenoid component and guide pin position based on surgeon preference. Patients were placed into 1 of 5 instrument groups used for intraoperative guide pin placement: (1) standard instrumentation, (2) standard instrumentation combined with use of a 3D glenoid bone model containing the guide pin, (3) use of the 3D glenoid bone model combined with single-use patient-specific instrumentation, (4) use of the 3D glenoid bone model combined with reusable patient-specific instrumentation, and (5) use of reusable patient-specific instrumentation with an adjustable, reusable base. Postoperatively, all patients underwent 3D CT to compare actual versus planned glenoid component position. Deviation from the plan (in terms of orientation and location) was compared across groups on the basis of absolute differences and outlier analysis. Univariable and multivariable comparisons were performed. As the initial analyses showed no significant differences in preoperative factors or in deviation from the plan between Groups 1 and 2 or between Groups 4 and 5 across studies, the final analysis was across 3 major treatment groups: standard instrumentation (Groups 1 and 2), single-use patient-specific instrumentation (Group 3), and reusable patient-specific instrumentation (Groups 4 and 5).Results: In nearly all comparisons, there were no significant differences in the deviation from the plan (absolute differences or outlier frequency) for glenoid implant orientation or location across the 3 major treatment groups.Conclusions: This study did not demonstrate that any type of patient-specific instrumentation resulted in consistent differences in accuracy of glenoid implant placement in primary TSA with 3D CT preoperative planning. Surgeons have multiple patient-specific instrumentation options available for improving accuracy of glenoid implant placement when compared with 2D imaging without patient-specific instrumentation.Level Of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Scapular notching is frequently observed following reverse total shoulder arthroplasty (rTSA), although the etiology is not well understood.Methods: Twenty-nine patients with preoperative computed tomography (CT) scans who underwent rTSA with a Grammont design were evaluated after a minimum of 2 years of follow-up with video motion analysis (VMA), postoperative three-dimensional (3D) CT, and standard radiographs. The glenohumeral range of motion demonstrated by the VMA and the postoperative implant location on the CT were used in custom simulation software to determine areas of osseous impingement between the humeral implant and the scapula and their relationship to scapular notching on postoperative CT. Patients with and without notching were compared with one another by univariable and multivariable analyses to determine factors associated with notching.Results: Seventeen patients (59%) had scapular notching, which was along the posteroinferior aspect of the scapular neck in all of them and along the anteroinferior aspect of the neck in 3 of them. Osseous impingement occurred in external rotation with the arm at the side in 16 of the 17 patients, in internal rotation with the arm at the side in 3, and in adduction in 12. The remaining 12 patients did not have notching or osseous impingement. Placing the glenosphere in a position that was more inferior (by a mean of 3.4 ± 2.3 mm) or lateral (by a mean of 6.2 ± 1.4 mm) would have avoided most impingement in the patients' given range of motion. Notching was associated with glenosphere placement that was insufficiently inferior (mean inferior translation, -0.3 ± 3.4 mm in the notching group versus 3.0 ± 2.9 mm in the no-notching group; p = 0.01) or posterior (mean, -0.3 ± 3.5 mm versus 4.2 ± 2.2 mm; p < 0.001). Two-variable models showed inferior and posterior (area under the curve [AUC], 0.887; p < 0.001), inferior and lateral (AUC, 0.892; p < 0.001), and posterior and lateral (AUC, 0.892; p < 0.001) glenosphere positions to be significant predictors of the ability to avoid scapular notching.Conclusions: Osseous impingement identified using patients' actual postoperative range of motion and implant position matched the location of scapular notching seen radiographically. Inferior, lateral, and posterior glenosphere positions are all important factors in the ability to avoid notching. Only small changes in implant position were needed to avoid impingement, suggesting that preoperative determination of the ideal implant position may be a helpful surgical planning tool to avoid notching when using this implant design.Level Of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Glenoid morphology and rotator cuff muscle quality are important anatomic factors that can impact longevity of the glenoid component following total shoulder arthroplasty (TSA). We hypothesized that rotator cuff muscle fatty infiltration is associated with increased pathologic glenoid bone loss in glenohumeral osteoarthritis (OA).Methods: We retrospectively reviewed 190 preoperative computed tomography (CT) scans of 175 patients (mean age, 66 years; range, 44 to 90 years) who underwent TSA for the treatment of primary glenohumeral OA. Two-dimensional orthogonal CT images were reformatted in the plane of the scapula from 3-dimensional images. Pathologic joint-line medialization was defined with use of the glenoid vault model. Pathologic glenoid version was measured directly. Glenoid morphology was graded according to a modified Walch classification (subtypes A1, A2, B1, B2, B3, C1, and C2). Rotator cuff muscle fatty infiltration was assessed and assigned a Goutallier score on the sagittal CT slice just medial to the spinoglenoid notch for each muscle.Results: There was a significant difference in the Goutallier score for the supraspinatus, infraspinatus, and teres minor muscles between Walch subtypes (p ≤ 0.05). High-grade posterior rotator cuff muscle fatty infiltration was present in 55% (21) of 38 B3 glenoids compared with 8% (3) of 39 A1 glenoids. Increasing joint-line medialization was associated with increasing fatty infiltration of all rotator cuff muscles (p ≤ 0.05). Higher fatty infiltration of the infraspinatus, teres minor, and combined posterior rotator cuff muscles was associated with increasing glenoid retroversion (p ≤ 0.05). After controlling for joint-line medialization and retroversion, B3 glenoids were more likely to have fatty infiltration of the supraspinatus and infraspinatus muscles than B2 glenoids were.Conclusions: High-grade rotator cuff muscle fatty infiltration is associated with B3 glenoids, increased pathologic glenoid retroversion, and increased joint-line medialization. Additional studies are needed to determine the causal relationship between these muscle changes and glenoid wear, whether these muscle changes independently affect clinical and radiographic outcomes in anatomic TSA, and whether fatty infiltration can improve postoperatively with correction of pathologic version and/or joint-line restoration.Clinical Relevance: This study investigates the association between different patterns of glenoid bone loss and rotator cuff muscle fatty infiltration. Both factors have been shown to affect clinical outcome following TSA. [ABSTRACT FROM AUTHOR]

ABSTRACT: The purpose of this study was to demonstrate feasibility of a clinical CT imaging and analysis technique to quantify regional variations in trabecular bone architecture and mineralization of glenoid bones. Specifically, our objective was to determine to what extent clinical CT imaging of intact upper extremities can describe variations of trabecular bone architectures at anatomic and peri‐implant regions by comparing trabecular bone architectures as measured by high‐resolution, micro CT imaging of same excised glenoid bones. Bone volume fraction (BVF), trabecular bone thickness (TbTh), number of trabecular bone (TbN), spacing (TbS), pattern factor (TbPf), bone surface area (BSA), and skeletal connectivity (Conn.), in addition to bone mineral content (BMC) and bone mineral density (BMD), were quantified from both clinical and micro CT images using whole bone, anatomic, and peri‐implant bone masks. Strong correlations of BVF, TbTh, TbSp, BMC, and BMD were found between clinical CT and micro CT imaging methods. The variations in BVF, TbTh, TbSp, TbN, BMC, and BMD at anatomical and peri‐implant regions were larger than those at whole bone regions. In this study, we have demonstrated that this clinical CT imaging methodology can be used to quantify variations of a patient's glenoid bone at anatomic and peri‐implant levels. Statement of Clinical Significance. An in vivo quantitative assessment of glenoid trabecular bone architecture in the anatomic and peri‐implant regions may improve our understanding on the role of bone quality on glenoid component loosening following total shoulder arthroplasty. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:85–96, 2018. [ABSTRACT FROM AUTHOR]

Background Whereas several studies suggest that high-volume surgeons and hospitals deliver superior patient outcomes with greater cost efficiency, no evidence-based thresholds separating high-volume surgeons and hospitals from those that are low or medium volume exist in shoulder arthroplasty. The objective of this study was to establish meaningful thresholds that take outcomes and cost into consideration for surgeons and hospitals performing shoulder arthroplasty. Methods Using 9546 patients undergoing primary shoulder arthroplasty for osteoarthritis from an administrative database, we created and applied 4 models using stratum-specific likelihood ratio (SSLR) analysis of a receiver operating characteristic (ROC) curve. We generated 4 sets of thresholds predictive of adverse outcomes, namely, increased length of stay (LOS) and increased cost for both surgeon and hospital volume. Results SSLR analysis of the 4 ROC curves by surgeon volume produced 3 volume categories. LOS and cost by annual shoulder arthroplasty surgeon volume produced the same strata: 0-4 (low), 5-14 (medium), and 15 or more (high). LOS and cost by annual shoulder arthroplasty hospital volume produced the same strata: 0-3 (low), 4-14 (medium), and 15 or more (high). LOS and cost decreased significantly ( P  < .05) in progressively higher volume categories. Conclusions Our study validates economies of scale in shoulder arthroplasty by demonstrating a direct relationship between volume and value through SSLR analysis of ROC curves for risk-based volume stratification using meaningful volume definitions for low-, medium-, and high-volume surgeons and hospitals. The described volume-value relationship offers patients, surgeons, hospitals, and other stakeholders meaningful thresholds for the optimal delivery of shoulder arthroplasty. [ABSTRACT FROM AUTHOR]

Purpose: The role of reverse total shoulder arthroplasty (RTSA) for three and four-part proximal humerus fractures is evolving. However, there does not appear to be a clear consensus amongst surgeons. The purpose of this study is to further define the standard of care, assessing surgeon preference and treatment considerations for management of such fractures.Methods: Orthopaedic surgeons were surveyed on their training, practice setting, and experience regarding management of four-part proximal humerus fractures. The survey also presented five representative cases to assess treatment preferences.Results: Two hundred five surgeons responded to the survey with fellowship training in shoulder and elbow surgery (114), orthopaedic trauma (35) or sports medicine/other training (56). There was no difference between respondents with years in practice and confidence with performing RTSA, however, surgeons in the academic setting were more confident in performing the surgery. Surgeons preferred RTSA for management of four-part fractures in patients over age 65. However, they also trended to favour hemiarthroplasty with higher co-morbidities. Physicians with more than 11 years of experience were more likely to choose hemiarthroplasty for older and high comorbidity patients. RTSA was not the preferred treatment method for younger, active patients. Patient age and fracture pattern had a greater influence on the surgeon's decision.Conclusions: There is a consensus in our study population that RTSA is the preferred treatment for four-part proximal humerus fractures for elderly patients with patient age and fracture pattern being the most important factors in making management decisions.Level Of Evidence: Level III - Case controlled study. [ABSTRACT FROM AUTHOR]

BACKGROUND: Propionibacterium acnes is recognized as a pathogenic organism associated with periprosthetic joint infection following shoulder arthroplasty. The goal of our study was to determine the relationship between the time to P. acnes growth in culture and the likelihood of a culture result being a true positive versus a false positive based on the proportion of positive cultures and other perioperative findings in cases of revision shoulder arthroplasty. METHODS: We retrospectively reviewed forty-six cases with P. acnes-positive cultures among patients who underwent revision shoulder arthroplasty between May 2010 and October 2014. Tissue and fluid was cultured anaerobically for a mean (and standard deviation) of 13.1 ± 3 days. Cases were categorized into one of two groups for analysis: probable true positive or probable contaminant (false-positive) on the basis of culture results and perioperative findings. RESULTS: The time to P. acnes culture growth was significantly shorter (p = 0.002) in the probable true-positive culture group compared with the probable contaminant group (median of five days [interquartile range, four to seven days]) compared with nine days [interquartile range, six to twelve days]). Among the thirty-seven cases in the probable true-positive group, no culture result turned positive after eleven days, whereas in the probable contaminant group, cultures turned positive after this time point in 44% (four of nine) of the cases. There were also significantly fewer days to P. acnes culture growth among cases with a higher number of positive cultures (p = 0.001) and a higher proportion of positive cultures (p < 0.001), regardless of group classification. CONCLUSIONS: P. acnes is the most commonly identified organism following revision shoulder arthroplasty. The proportion of positive cultures and the timing of culture growth may help to distinguish a true-positive from a false-positive culture result. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Diagnosis of periprosthetic joint infection (PJI) in patients undergoing revision shoulder arthroplasty is challenging because of the low virulence of the most common infecting organisms. The goal of this study was to evaluate the diagnostic utility of measuring synovial fluid interleukin-6 (IL-6) levels for identifying PJI of the shoulder. Methods: Thirty-two consecutive patients evaluated for pain at the site of a shoulder arthroplasty were prospectively enrolled from November 2012 to September 2013 and underwent revision surgery (thirty-five procedures during which samples were obtained for synovial fluid IL-6 analysis). Cases were categorized into infection (n = 15) and no-infection (n = 20) groups on the basis of objective preoperative and intraoperative findings. Twenty patients treated with arthroscopic rotator cuff repair were also enrolled to serve as a non-infected control group. Synovial fluid was obtained through aspiration intraoperatively for all patients, as well as preoperatively for some. Synovial fluid IL-6 levels were measured with use of a cytokine immunoassay that utilizes electrochemiluminescent detection. A receiver operating characteristic curve was used to determine the diagnostic utility of synovial fluid IL-6 analysis. Results: Based on receiver operating characteristic curve analysis, synovial fluid IL-6 measurement had an area under the curve of 0.891 with an ideal cutoff value of 359.3 pg/mL. The sensitivity, specificity, and positive and negative likelihood ratios were 87%, 90%, 8.45, and 0.15, respectively. Seven patients who underwent a single-stage revision had negative results on standard perioperative testing, including the erythrocyte sedimentation rate and C-reactive protein levels, but multiple positive intraoperative tissue cultures. The level of synovial fluid IL-6 was elevated in five of these seven patients, with a median value of 1400 pg/mL. Intraoperative synovial fluid IL-6 values correlated well with preoperative IL-6 synovial fluid values (correlation = 0.61; p = 0.025) and frozen-section histologic findings (p < 0.001). Synovial fluid IL-6 levels were also significantly elevated in patients with Propionibacterium acnes infection (p = 0.01). Conclusions: Measurement of synovial fluid IL-6 levels is more sensitive and specific than current preoperative testing for predicting positive cultures for patients undergoing revision shoulder arthroplasty. This diagnostic accuracy can lead to improved decision-making in the management of PJI. Level of Evidence: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Objective: Iterative metal artifact reduction (IMAR) is a sinogram inpainting technique that incorporates high-frequency data from standard weighted filtered back projection (WFBP) reconstructions to reduce metal artifact on computed tomography (CT). This study was designed to compare the image quality of IMAR and WFBP in total shoulder arthroplasties (TSA); determine the optimal amount of WFBP high-frequency data needed for IMAR; and compare image quality of the standard 3D technique with that of a faster 2D technique. Materials and methods: Eight patients with nine TSA underwent CT with standardized parameters: 140 kVp, 300 mAs, 0.6 mm collimation and slice thickness, and B30 kernel. WFBP, three 3D IMAR algorithms with different amounts of WFBP high-frequency data (IMARlo, lowest; IMARmod, moderate; IMARhi, highest), and one 2D IMAR algorithm were reconstructed. Differences in attenuation near hardware and away from hardware were measured and compared using repeated measures ANOVA. Five readers independently graded image quality; scores were compared using Friedman's test. Results: Attenuation differences were smaller with all 3D IMAR techniques than with WFBP ( p < 0.0063). With increasing high-frequency data, the attenuation difference increased slightly (differences not statistically significant). All readers ranked IMARmod and IMARhi more favorably than WFBP ( p < 0.05), with IMARmod ranked highest for most structures. The attenuation difference was slightly higher with 2D than with 3D IMAR, with no significant reader preference for 3D over 2D. Conclusions: IMAR significantly decreases metal artifact compared to WFBP both objectively and subjectively in TSA. The incorporation of a moderate amount of WFBP high-frequency data and use of a 2D reconstruction technique optimize image quality and allow for relatively short reconstruction times. [ABSTRACT FROM AUTHOR]

Background: We hypothesized that a novel surgical method, in which three-dimensional (3-D) preoperative planning software is generated to create a patient-specific surgical model that is used with a reusable and adjustable tool, could substantially improve the positioning accuracy of the glenoid guide pin used in total shoulder arthroplasty. We tested this method using bone models from patients with shoulder pathology and compared the results with those achieved using surgical methods representing the current standard of care. Methods: Three surgeons with a variety of surgical experience placed a guide pin in nine bone models from patients with a variety of glenohumeral arthritis severity using (1) standard instrumentation alone, (2) standard instrumentation and 3-D preoperative surgical planning, and (3) the reusable transfer device and 3-D preoperative surgical planning. A postoperative 3-D computed tomography scan of the bone model was made and registered to the preoperative plan, and the differences between the actual and planned pin locations and trajectories were measured. Results: Use of the standard instrumentation combined with 3-D preoperative planning software improved guide pin positioning compared with standard instrumentation and preoperative planning using 2-D imaging. The accuracy of pin positioning increased by 4.5° ± 1.0° in version (p < 0.001), 3.3° ± 1.3° in inclination (p = 0.013), and 0.4 ± 0.2 mm in location (p = 0.042). Use of the adjustable and reusable device and the 3-D software improved pin positioning by a further 3.7° ± 0.9° in version, 8.1° ± 1.2° in inclination, and 1.2 ± 0.2 mm in location (p < 0.001 for all) compared with standard instrumentation and the 3-D software; the improvement compared with use of standard instrumentation with 2-D imaging was 8.2° ± 0.9° in version, 11.4° ± 1.2° in inclination, and 1.7 ± 0.2 mm in location (p < 0.001 for all). Conclusions: Use of 3-D preoperative planning and use of the patient-specific bone model and transfer device both improved the positioning accuracy of the pin used to guide placement of the glenoid component in total shoulder arthroplasty. Clinical Relevance: Proper positioning of the glenoid component would be expected to improve the function and durability of the joint replacement. [ABSTRACT FROM AUTHOR]

Background: Glenoid bone loss associated with advanced glenohumeral arthritis is frequently accompanied by subluxation of the humeral head with subsequent inferior outcomes of shoulder arthroplasty. We hypothesized that the relationship between the center of the humeral head and the perpendicular to the glenoid fossa plane differs from, and is independent of, the relationship between the center of the humeral head and the plane of the scapula. Methods: Three-dimensional computed tomography (3D CT) imaging was performed on sixty patients with advanced osteoarthritis and fifteen controls with no osteoarthritis to define the baseline relationship between the center of the humeral head and the perpendicular to the glenoid fossa plane and the plane of the scapula. Correlations between these variables and the amount of bone loss and glenoid version were assessed. Results: There was a strong linear relationship (p < 0.001) between glenoid retroversion and the center of the humeral head in relation to the center line of the scapula (humeral-scapular alignment). Humeral head alignment in relation to the glenoid plane (humeral-glenoid alignment) was variable and not strongly correlated with the amount of glenoid retroversion. The average glenoid retroversion for the normal shoulders was -3.5°, and the average humeral-scapular alignment offset percentage was -2.3%. The average humeral-glenoid alignment offset for the normal shoulders was 0.5 mm with an average humeral-glenoid alignment offset percentage of 0.9%. Conclusions: The location of the humeral head in relation to the glenoid can be defined as displacement from the plane of the scapula and from the perpendicular of the glenoid plane. These two measures are independent of one another. The data suggest that each measurement may represent a different effect on glenoid loading. [ABSTRACT FROM AUTHOR]

Background: Propionibacterium acnes is a clinically relevant pathogen with total shoulder arthroplasty. The purpose of this study was to determine the sensitivity of frozen section histology in identifying patients with Propionibacterium acnes infection during revision total shoulder arthroplasty and investigate various diagnostic thresholds of acute inflammation that may improve frozen section performance. Methods: We reviewed the results of forty-five patients who underwent revision total shoulder arthroplasty. Patients were divided into the non-infection group (n = 15), the Propionibacterium acnes infection group (n = 18), and the other infection group (n = 12). Routine preoperative testing was performed and intraoperative tissue culture and frozen section histology were collected for each patient. The histologic diagnosis was determined by one pathologist for each of the four different thresholds. The absolute maximum polymorphonuclear leukocyte concentration was used to construct a receiver operating characteristics curve to determine a new potential optimal threshold. Results: Using the current thresholds for grading frozen section histology, the sensitivity was lower for the Propionibacterium acnes infection group (50%) compared with the other infection group (67%). The specificity of frozen section was 100%. Using a receiver operating characteristics curve, an optimized threshold was found at a total of ten polymorphonuclear leukocytes in five high-power fields (400·). Using this threshold, the sensitivity of frozen section for Propionibacterium acnes was increased to 72%, and the specificity remained at 100%. Conclusions: Using current histopathology grading systems, frozen sections were specific but showed low sensitivity with respect to the Propionibacterium acnes infection. A new threshold value of a total of ten or more polymorphonuclear leukocytes in five high-power fields may increase the sensitivity of frozen section, with minimal impact on specificity. Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Restoration of native, premorbid glenoid anatomy may be a goal in component placement during total shoulder arthroplasty. However, if patients with unilateral glenohumeral osteoarthritis are predisposed to the development of arthritis owing to abnormal native glenoid anatomy, this recommendation may be inappropriate. Questions/purposes: The purpose of this study was to determine if patients with glenohumeral osteoarthritis have abnormal premorbid glenoid version or inclination, thereby predisposing them to subsequent glenoid disorders. We specifically tested whether: (1) premorbid glenoid version or inclination in the pathologic shoulder of patients with unilateral osteoarthritis, as determined by the glenoid vault model, is different from glenoid version or inclination in the contralateral nonpathologic shoulder of these patients; (2) there are differences between glenoid version or inclination in normal cadaver shoulders and the nonpathologic side of patients with unilateral osteoarthritis; and (3) there are differences between glenoid version or inclination in normal cadaver shoulders and the premorbid glenoid version and inclination in the pathologic shoulder of patients with unilateral osteoarthritis, as determined by the glenoid vault model. Methods: Bilateral CT scans were obtained in 27 patients with unilateral glenohumeral osteoarthritis. Thirty normal cadaver control shoulders also underwent CT scans. Premorbid glenoid version and inclination in the pathologic shoulder, as measured by the glenoid vault model, were compared with the contralateral nonpathologic shoulder and the normal cadaver control shoulders. Glenoid version and inclination of the normal shoulders were compared with the nonpathologic side from patients with unilateral osteoarthritis. Measurements were made by two different methods using three-dimensional surgical simulation software: (1) a direct measurement technique and (2) measurements derived from placement of a glenoid vault model. Mean differences in these parameters were compared between shoulder groups using paired and unpaired Student's t-tests. Results: Premorbid glenoid version and inclination in the pathologic shoulder as measured by the vault model averaged −7° (SD, 5) and 10° (SD, 6), respectively, compared with −7° (SD, 5) and 12° (SD, 6) as directly measured on the nonpathologic side, and −7° (SD, 4) and 12° (SD, 5) as directly measured in the normal cadaver control shoulders. There were no differences in glenoid version or inclination between the normal shoulders and the nonpathologic side of patients with unilateral osteoarthritis or between these shoulders and the premorbid version and inclination of the arthritic shoulder as measured by the vault model. Conclusions: Patients with glenohumeral osteoarthritis do not appear to have abnormal premorbid glenoid retroversion or inclination. The glenoid vault model can be used to determine premorbid glenoid version and inclination. Clinical Relevance: The glenoid vault model may be a clinically useful tool to estimate patient-specific premorbid glenoid anatomy, which may help in preoperative or intraoperative surgical planning for total shoulder arthroplasty. Level of Evidence: Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Glenohumeral osteoarthritis may be associated with severe posterior glenoid bone loss and glenoid retroversion. Treatment with total shoulder arthroplasty and autologous bone graft obtained from the humeral head has been infrequently reported in the peer-reviewed literature. Methods: The clinical and radiographic results of primary total shoulder replacement with an all-polyethylene glenoid component and autologous humeral head graft augmentation performed by a single surgeon in thirteen consecutive patients were evaluated. Results: Twelve of the thirteen patients were followed for a minimum of two years (average, fifty-three months; range, twenty-six to 110 months). The average glenoid retroversion on preoperative computed tomography (CT) scans was 44° (range, 20° to 65°). Based on the Walch classification of pathologic glenoid morphology, nine glenoids were B2 and three were type C. All patients had an intact cuff at the time of surgery. At the time of the last follow up, ten of the twelve patients had graft incorporation without any resorbtion and two had minor bone graft resorption. Broken screws occurred in two of these ten cases. Two patients, both of whom required revision surgery, had failure of fixation and of graft incorporation; one of these failures was due to early postoperative trauma and the other, to Propionibacterium acnes infection. Conclusions: The early and midterm results of total shoulder arthroplasty with autogenous bone graft demonstrated substantial clinical and radiographic improvement in most cases. Level of Evidence: Therapeutic Leve IV. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Recent studies have detailed the significance of indolent infections in revision shoulder arthroplasty, but little information is available to guide treatment strategies regarding patients with positive cultures without overt signs of infection. The primary purpose of this study was to determine recurrence rates of infection for patients undergoing revision shoulder arthroplasty who were not treated for infection but had positive intraoperative cultures. Materials and methods: We retrospectively reviewed the results of 17 patients undergoing revision of a failed shoulder joint replacement with at least 1 positive intraoperative culture who were not treated for infection because of limited signs of infection before or at the time of revision surgery. These patients underwent 1-stage revision surgery without an extended intravenous antibiotic regimen. Results: The recurrence rate of infection for the 17 patients was 5.9%. The most common pathogen cultured at revision surgery was Propionibacterium acnes (10 of 17 [56%]), followed by coagulase-negative Staphylococcus species (6 of 17 [35%]). Conclusion: We found that low-virulence and clinically unexpected infections treated with 1-stage revision have a low risk for recurrent infection. This study suggests that intensive antimicrobial treatment strategies may not be necessary to reduce recurrent infections in patients with positive intraoperative cultures, without overt clinical signs of infection before or during the revision surgery. [ABSTRACT FROM AUTHOR]

Background: Loosening of the glenoid component continues to be the foremost cause of medium and long-term failure of shoulder replacements. The purpose of this study was to evaluate the clinical and radiographic results of a minimally cemented all-polyethylene pegged glenoid component designed for biologic fixation. Methods: Forty-four shoulders in forty-one patients with a mean age of sixty-six years underwent total shoulder arthroplasty with a pegged bone-ingrowth glenoid component. Outcome data included the American Shoulder and Elbow Surgeons questionnaire, the Simple Shoulder Test, and visual analog scales. A detailed radiographic analysis was performed by two board-certified musculoskeletal radiologists who were blinded to clinical and patient-reported outcomes. The radiographs were evaluated with regard to the presence of radiolucent lines at the bone-cement interface, implant seating, and the radiodensity between the flanges of the central peg. Results: The mean duration of clinical follow-up was four years and the mean duration of radiographic follow-up was three years. Twenty shoulders had perfect seating and radiolucency grades, thirty had increased radiodensity between the flanges of the central peg, and three demonstrated osteolysis. Radiodensity about the uncemented central peg at the time of the latest follow-up was positively associated with perfect seating and radiolucency grades on the initial postoperative radiographs (p = 0.03, Fisher exact test). The Simple Shoulder Test score, the American Shoulder and Elbow Surgeons score, and all visual analog scale scores had improved significantly (p < 0.01) at the time of the latest follow-up. Conclusions: Total shoulder arthroplasty with a minimally cemented, all-polyethylene, pegged glenoid implant can yield stable and durable fixation at short to medium-term follow-up (mean, four years). [ABSTRACT FROM AUTHOR]

Background: Malposition of the glenoid component can result in premature component loosening or instability. This study was designed to test the ability of an experienced shoulder surgeon to position the glenoid component using standard preoperative planning and surgical bone preparation. Materials and methods: Thirteen patients having primary total shoulder arthroplasty were evaluated using 3-dimensional surgical simulator. Ideal version was considered to have version as close to perpendicular to the plane of the scapula, with complete contact of the back side of the component on glenoid bone and maintenance of the center peg of the component within bone. Results: The average retroversion angle was 13° (mean, standard deviation [SD] 12°), with a range of 1-42°. In 7 of these 13 cases, preoperative glenoid retroversion was greater or equal to 10°. In 3 cases, the component was malpositioned with greater than 10° of ideal version. In cases with less than 10° of preoperative retroversion, the glenoid component was placed within 10° of ideal version in all cases. Conclusion: Traditional methods to correct moderate to severe glenoid deformity and place the glenoid component within 5° of the ideal position are not consistent. Optimal glenoid component placement can be achieved when there is minimal bone deformity. Retroversion greater or equal to 20° makes it difficult to place a pegged glenoid component perpendicular to the plane of the scapula by asymmetric reaming without center peg perforation. [Copyright &y& Elsevier]

Background: Correction of pathologic glenoid retroversion improves gleonhumeral mechanics and reduces glenoid component wear after total shoulder arthroplasty. Determining the amount of correction necessary can be difficult because of the wide range of normal glenoid version. We hypothesize that normal glenoid version can be predicted in a pathologic shoulder based on conserved relationships between the anterior glenoid wall, Resch angle, and the internal structures of the glenoid vault. Materials and methods: Three-dimensional (3-D) computer tomography (CT) scan-based measurements of the anterior glenoid wall angle (AGWA), Resch angle (RA), and glenoid version were made in 58 scapulae from the Haeman-Todd Osteological Collection (Museum of Natural History in Cleveland, OH) and 19 paired scapulae from patients with unilateral osteoarthritis. Linear regression equations derived from the AGWA and RA and from a computer-generated vault model were used to predict native (nonpathologic) glenoid version as defined by the 19 nonpathologic scapula. Results: Linear regression equations based on the measured AGWA or RA, as well as the glenoid vault model in the 19 pathologic scapulae, were able to accurately predict native glenoid version in the contralateral nonpathologic shoulder. Discussion: This study demonstrates the ability to take 3-D CT scan-based measurements in a scapula with pathologic glenoid retroversion and predict the native (nonpathologic) glenoid version in the contralateral shoulder by using linear regression equations or a computer generated vault model. Such tools might assist in preoperative planning and intraoperative decision making to allow correction of pathologic glenoid retroversion. [Copyright &y& Elsevier]

Background: Recently, a lesser tuberosity osteotomy has been promoted as an alternative to tenotomy for release of the subscapularis during shoulder arthroplasty. To our knowledge, no direct comparison of the clinical results of the two techniques has been presented. Methods: Thirty-five shoulders in thirty-four consecutive patients with osteoarthritis who had a primary total shoulder arthroplasty, performed with use of a standard subscapularis tenotomy (Group 1) or lesser tuberosity osteotomy (Group 2) to release the subscapularis, were evaluated retrospectively at an average of thirty-three months. Group 1 consisted of fifteen shoulders in fourteen patients (seven in males and eight in females, with an average age of sixty-seven years). Group 2 consisted of twenty shoulders in twenty patients (fourteen males and six females, with an average age of sixty-nine years). Assessment included a physical examination, clinical outcome questionnaires, conventional radiography, ultrasound examination of the subscapularis, and measurement of internal rotation strength. Results: The postoperative total Penn Shoulder Scores improved significantly from the preoperative levels in both groups (mean and standard deviation, 29 ± 15 points to 81 ± 20 points [p < 0.00001] in Group 1 and 29 ± 16 points to 92 ± 11 points [p < 0.00001] in Group 2). However, the postoperative mean total Penn Shoulder Score was higher in Group 2 (92 ± 11 points) than in Group 1 (81 ± 20 points) (p = 0.04). At one year, an abnormal subscapularis on ultrasound was associated with a lower mean Penn Shoulder Score in Group 1 (73 ± 19 points compared with 92 ± 3 points; p = 0.01). However, at a minimum two-year follow-up, this difference was not significant (mean, 74 ± 24 points and 86 ± 15 points, respectively; p = 0.25). There were more abnormal subscapularis tendons in Group 1 (six attenuated tendons and one full-thickness tear) than in Group 2 (two attenuated tendons). Internal rotation strength did not differ between the groups when controlled for sex (mean, 117 ± 8 N and 127 ± 21 N for males in Group 1 and Group 2, respectively [p = 0.22] and 77 ± 27 N and 101 ± 26 N, respectively, for females [p = 0.1]). Conclusions: Both techniques resulted in improved clinical outcome scores. The lesser tuberosity osteotomy resulted in higher clinical outcome scores, a lower rate of subscapularis tendon tears, and universal healing of the osteotomy. This technique offers a means by which the rate of postoperative subscapularis tears may be reduced in patients undergoing total shoulder arthroplasty. Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

BACKGROUND: While there have been numerous reports concerning glenohumeral arthrodesis for many indications, there is little available information specific to glenohumeral arthrodesis performed after failed prosthetic shoulder arthroplasty. The purpose of this study was to report the outcomes of glenohumeral arthrodesis in the setting of severe glenohumeral bone loss and deltoid muscle and rotator cuff insufficiency following failed prosthetic shoulder arthroplasty. METHODS: We retrospectively reviewed clinical and radiographic data on seven consecutive patients treated with glenohumeral arthrodesis following a failed prosthetic shoulder arthroplasty between 1997 and 2004. The average duration of clinical follow-up was four years (range, 1.5 to eight years). RESULTS: Five of the seven patients demonstrated an intact fusion at the time of the latest follow-up. Four of the seven patients had undergone additional bone-grafting procedures in an effort to obtain union. Two of these patients ultimately had a persistent nonunion despite the additional procedures for bone-grafting and revision of the fixation hardware. Overall, the average subjective clinical outcome score (Penn Shoulder Score) improved significantly from 17 points (range, 8 to 33 points) to 58 points (range, 31 to 77 points) (p = 0.008). The most common complication was delayed union requiring additional procedures for bone-grafting and revision of the fixation hardware. CONCLUSIONS: Treatment of a failed prosthetic shoulder arthroplasty with concomitant extensive glenohumeral bone loss and soft-tissue deficiencies is extremely challenging. The results of this study suggest that glenohumeral arthrodesis can yield satisfactory clinical outcomes. However, both the patient and the surgeon should be aware of the complex nature of this surgery and the frequent need for additional surgical procedures to obtain fusion. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Arthritic changes to glenoid morphology can be difficult to fully characterize on both plain radiographs and conventional two-dimensional computer tomography images. We tested the hypothesis that three-dimensional imaging of the shoulder would increase inter-rater agreement for assessing the extent and location of glenoid bone loss and also would improve surgical planning for total shoulder arthroplasty. Methods: Four shoulder surgeons independently and retrospectively reviewed the preoperative computed tomography scans of twenty-four arthritic shoulders. The blinded images were evaluated with conventional two-dimensional imaging software and then later with novel three-dimensional imaging software. Measurements and preoperative judgments were made for each shoulder with use of each imaging modality and then were compared. The glenoid measurements were glenoid version and bone loss. The judgments were the zone of maximum glenoid bone loss, glenoid implant fit within the glenoid vault, and how to surgically address abnormal glenoid version and bone loss. Agreement between observers was evaluated with use of intraclass correlation coefficients and the weighted kappa coefficient (K), and we determined if surgical decisions changed with use of the three-dimensional data. Results: The average glenoid version (and standard deviation) measured - 17° ± 2.2° on the two-dimensional images and -19° ± 2.4° on the three-dimensional images (p < 0.05). The average posterior glenoid bone loss measured 9 ± 2.3 mm on the two-dimensional images and 7 ± 2 mm on the three-dimensional images (p < 0.05). The average anterior bone loss measured 1 mm on both the two-dimensional and the three-dimensional images. However, the intraclass correlation coefficients for anterior bone loss increased significantly with use of the three-dimensional data (from 0.36 to 0.70; p < 0.05). Observers were more likely to locate mid-anterior glenoid bone loss on the basis of the three-dimensional data (p < 0.05). The use of three-dimensional data provided greater agreement among observers with regard to the zone of glenoid bone loss, glenoid prosthetic fit, and surgical decision-making. Also, when the judgment of implant fit changed, observers more often determined that it would violate the vault walls on the basis of the three-dimensional data (p < 0.05). Conclusions: The use of three-dimensional imaging can increase inter-rater agreement for the analysis of glenoid morphology and preoperative planning. Important considerations such as the extent and location of glenoid bone loss and the likelihood of implant fit were influenced by the three-dimensional data. Clinical Relevance: We believe that these data support the concept that three-dimensional imaging techniques applied to the shoulder provide further information that may be useful to the surgeon during the planning of total shoulder arthroplasty. [ABSTRACT FROM AUTHOR]

We retrospectively reviewed 32 patients who underwent glenoid revision surgery after total shoulder arthroplasty to compare the results of revision total shoulder arthroplasty with those of revision hemiarthroplasty and to identify factors associated with poor results after revision shoulder arthroplasty for glenoid component loosening. Results were reviewed at a mean follow-up of 4 years (range, 2-8 years). Glenoid reimplantation resulted in significant pain relief (P < .0001), improvement in American Shoulder and Elbow Surgeons (ASES) score (P < .02), and external rotation (24° to 44°, P < .004). Revision to a hemiarthroplasty also resulted in significant pain relief (P < .01) and improvement in ASES score (P < .05). For the treatment of glenoid loosening without glenohumeral instability, both reimplantation of a glenoid component and revision to a hemiarthroplasty improved function, satisfaction, and level of pain. Reimplantation of a new glenoid component offered greater improvements in pain (P < .008) and external rotation (increase of 20° versus 3°, P < .03) compared with hemiarthroplasty. For patients with preoperative glenohumeral instability, revision surgery did not improve motion, function, or pain significantly. Risk factors associated with a poor outcome after revision arthroplasty included persistent glenohumeral instability, rotator cuff tears, and malunion of the greater tuberosity. [Copyright &y& Elsevier]

Background: Posterior glenoid bone loss is often seen in association with glenohumeral osteoarthritis. This posterior asymmetric wear can lead to retroversion of the glenoid component and posterior instability after total shoulder arthroplasty. Options for the treatment of this asymmetric wear include eccentric reaming of the so-called high side, bone-grafting, and/or anteverting the humeral component. Although anteverting the humeral component has been advocated by many, it has not been substantiated on the basis of biomechanical data. The purpose of the present study was to determine whether anteverting the humeral component increases the stability of a total shoulder replacement with a retroverted glenoid component. Methods: A total shoulder arthroplasty was performed in eight human cadaveric shoulders. The glenoid component was placed in 15° of retroversion. Two humeral versions were tested for each specimen: anatomic version and 15° of anteversion relative to anatomic version. The specimens wore mounted supine in a custom fixture on a servohydraulic testing system. The humerus WaS translated posteriorly by one-half of the width of the glenoid. Three positions of humeral relation were tested for each position of humeral version. Both the energy and the peak load were analyzed as measures of joint stability. Results: There was no significant difference in either energy or peak load between the tests performed with the humeral component in 15° of anteversion and those performed with the component in anatomic version in any of the three rotational positions (p > 0.05). Conclusions: Although anteverting the humeral component during total shoulder arthroplasty to compensate for glenoid retroversion has been advocated, these data suggest that compensatory anteversion of the humeral compo- nent does not increase the stability of a shoulder replacement with a retroverted glenoid component. Clinical Relevance: These data further suggest that restoring a more neutral glenoid surface might be preferred when the surgeon is presented with posterior glenoid bone loss. [ABSTRACT FROM AUTHOR]

Background: The results of shoulder arthroplasty for osteoarthritis have been reported to be excellent or good for the majority of patients, but the value of using a glenoid component and the anatomic factors that affect outcome are still debated. The purpose of this study was to evaluate the influence of an operatively confirmed full-thickness tear of the rotator cuff, the severity of preoperative erosion of glenoid bone, preoperative radiographic evidence of subluxation of the humeral head, and the severity of preoperative loss of the passive range of motion on the outcome of total shoulder arthroplasty and hemiarthroplasty. Methods: In a multicenter clinical outcome study, we evaluated 128 shoulders in 118 patients with primary osteoarthritis who had been followed for a mean of forty-six months (range, twenty-four to eighty-seven months). Results: Patients with <10° of passive external rotation preoperatively had significantly less improvement in external rotation after hemiarthroplasty (p = 0.006). Thirteen (10%) of the 128 shoulders had a repairable full-thickness tear of the supraspinatus tendon, but these tears did not affect the overall American Shoulder and Elbow Surgeons score, the decrease in pain, or patient satisfaction. Severe or moderate eccentric glenoid erosion was seen in twenty-nine (23%) of the 128 shoulders, and total shoulder arthroplasty resulted in significantly better passive total elevation and active external rotation as well as a trend toward significantly better active forward flexion than did hemiarthroplasty in these shoulders. The humeral head was subluxated posteriorly in twenty-three shoulders (18%), and when they were compared with the other shoulders in the study, these shoulders were found to have lower final American Shoulder and Elbow Surgeons scores, more pain, and decreased active external rotation following either total shoulder arthroplasty or hemiarthroplasty. Conclusions: On the basis of our data, we recommend... [ABSTRACT FROM AUTHOR]

Management of glenoid bone loss in shoulder arthroplasty is challenging. Currently available prosthetic, biologic, and composite prosthetic and biologic solutions are not ideal. The most common solutions involve a combination of asymmetric reaming, bone grafting, and standard polyethylene components. The development of additional prosthetic and biologic solutions may require a change in the way glenoid bone loss and component fixation are conceptualized. Classifications should be modified to consider the portions of the glenoid still remaining for fixation. In addition, the concept of placing glenoid components in the glenoid vault rather than on the subchondral surface, which is often deficient, should be developed. These changes may result in mass-produced glenoid components that could make management of glenoid bone loss more reproducible. [Copyright &y& Elsevier]

Screw fixation is often required for glenoid implants and glenoid bone grafting, yet no study has evaluated the complex and irregular anatomy of the scapula to determine the best positions for the screws. Current implants rely solely on the bone in the glenoid vault for screw fixation, but in cases with glenoid bone loss, screw fixation may not confer adequate stability. The purpose of this study was to find the best positions for screws that are secured in bone beyond the glenoid vault. Twenty-seven scapulae from the Hamann-Todd osteologic collection underwent a computed tomography scan, and the images were transferred to a custom computer program that allowed 3-dimensional manipulation of the scapular images. Virtual screws were inserted into the scapula through the glenoid fossa, and the starting points and screw lengths were recorded. The coordinates of the starting points were scaled to allow comparisons among the different sizes of scapula. Once the ideal screw position was found, the angle of insertion was altered by 15° in 4 directions, and the resulting screw length was recorded to show the effects of screw insertion error. Three screws could be inserted through the glenoid fossa into bone beyond the glenoid vault. The superior screw had a median length of 29 mm and exited at the junction of the coracoid and the suprascapular notch. The middle screw had a median length of 60 mm and exited at the junction of the spine and the scapular body. The inferior screw had a median length of 75 mm and exited posterior to the tip of the scapula. When the starting positions were constrained by a symmetric implant, the median superior screw length was 19 mm, the median inferior screw length was 61 mm, and the median middle screw length was 55 mm. Screw fixation in bone beyond the glenoid vault can be used for fixation of glenoid implants or glenoid bone grafting. Future studies are required to test the biomechanical stability of this new screw configuration, as well as methods and tools for precise implantation of the screws into the described locations. Once these studies are completed revision total shoulder arthroplasty with severe glenoid bone loss may be treated in 1 stage with screw fixation of a glenoid implant over bulk allograft. [Copyright &y& Elsevier]