Zoledronate alleviates subchondral bone collapse and articular cartilage degeneration in a rat model of rotator cuff tear arthropathy.

OBJECTIVE: To evaluate the humeral head bone volume of patients with cuff tear arthropathy (CTA) and examine the therapeutic effect of zoledronate in a rat modified model of CTA (mCTA). DESIGN: The bone mass in patients with CTA was measured using Hounsfield units from CT images. The mCTA was induced by transecting the rotator cuff, biceps brachii tendon, and superior half of the joint capsule in adult rat shoulders. A single subcutaneous injection of zoledronate was followed by bone histomorphometry and immunohistochemistry of the humeral head, as well as the Murine Shoulder Arthritis Score (MSAS) assessment. RESULTS: The humeral head bone volume was decreased in patients with CTA. In the mCTA model, M1 macrophages were increased in the synovium and were decreased by zoledronate treatment. The increased expressions of TNF-α, IL-1ß and IL-6 in mCTA synovium and articular cartilage were suppressed in the zoledronate-treated mCTA group. The expression of catabolic enzymes in the articular cartilage and MSAS showed similar results. The zoledronate-treated mCTA group showed a decreased subchondral bone collapse with a decreased RANKL/OPG expression ratio and a suppressed number of osteoclasts compared with the control mCTA group. The enhanced expressions of HMGB1 and S100A9 in the mCTA shoulders were eliminated in the zoledronate-treated mCTA group. CONCLUSIONS: The humeral head subchondral bone was decreased in patients with CTA. In the mCTA model, the collapse and osteoarthritic changes were prevented by zoledronate administration. Zoledronate seemed to suppress the number of M1 macrophages in the synovium and osteoclasts in the subchondral bone.

The effect of cuff arthropathy stage on sleep disturbance and kinesiophobia in reverse shoulder arthroplasty patients.

BACKGROUND: The current study aimed to determine the changes in pre-and post-operative Pittsburg sleep quality index (PSQI) and Tampa scale of kinesiophobia (TSK) values ​​according to the Hamada classification in patients who underwent reverse shoulder arthroplasty (RSA) for rotator cuff tear arthropathy (RCTA). METHODS: One hundred and eight patients who underwent RSA for RCTA were reviewed retrospectively. The patients were divided into two groups with low grade (stages 1-2-3) (n = 49) and high grade (stages 4a-4b-5) (n = 59) according to the Hamada classification, which is the radiographic evaluation of RCTA. PSQI and TSK values ​​were calculated preoperatively, and post-operatively at the 6th week, 6th month, and 1st year. The change in PSQI and TSK values ​​between the evaluations and the effect of staging according to the Hamada classification on this change was examined. RESULTS: When compared in preoperative evaluations, PSQI and TSK scores were found to be lower in low-grade group 1 (7.39 ± 1.56, 51.88 ± 4.62, respectively) than in high-grade group 2 (10.47 ± 2.39, 57.05 ± 3.25, respectively) according to Hamada classification (both p < 0.001). In the postoperative evaluations, PSQI and TSK results decreased gradually compared to the preoperative evaluations, and there was a severe decrease in both parameters between the 6th-week and 6th-month evaluations (both p < 0.001). Preoperatively, 102 (95%) patients had sleep disturbance (PSQI ≥ 6), and 108 (100%) patients had high kinesiophobia (TSK > 37). In the 1st year follow-ups, sleep disturbance was observed in 5 (5%) patients and kinesiophobia in 1 (1%) patient. When the Hamada stages were compared, it was seen that there was a significant difference before the operation (both p < 0.001), but the statistically significant difference disappeared in the PSQI value in the 1st year (p = 0.092) and in the TSK value in the 6th month (p = 0.164) post-operatively. It was observed that Hamada staging caused significant differences in PSQI and TSK values ​​in the preoperative period but did not affect the clinical results after treatment. CONCLUSIONS: RSA performed based on RCTA improves sleep quality and reduces kinesiophobia. RCTA stage negatively affects PSQI and TSK before the operation but does not show any effect after the treatment.

Managing rotator cuff tear arthropathy: a role for cuff tear arthropathy hemiarthroplasty as well as reverse total shoulder arthroplasty.

BACKGROUND: Disabling cuff tear arthropathy (CTA) is commonly managed with reverse shoulder arthroplasty (RSA). However, for patients with CTA having preserved active elevation, cuff tear arthropathy hemiarthroplasty (CTAH) may offer a cost-effective alternative that avoids the complications unique to RSA. We sought to determine the characteristics and outcomes of a series of patients with CTA managed with these procedures. MATERIALS AND METHODS: We retrospectively reviewed 103 patients with CTA treated with shoulder arthroplasty, the type of which was determined by the patient's ability to actively elevate the arm. Outcome measures included the change in the Simple Shoulder Test (SST), the percent maximum improvement in SST (%MPI), and the percentage of patients exceeding the minimal clinically important difference for the change in SST and %MPI. Postoperative x-rays were evaluated to assess the positions of the center of rotation and the greater tuberosity for each implant. RESULTS: Forty-four percent of the 103 patients were managed with CTAH while 56% were managed with RSA. Both arthroplasties resulted in clinically significant improvement. Patients having RSA improved from a mean preoperative SST score of 1.7 (interquartile range [IQR], 0.0-3.0) to a postoperative score of 6.3 (IQR, 2.3-10.0) (P < .01). Patients having CTAH improved from a preoperative SST score of 3.1 (IQR, 1.0-4.0) to a postoperative score of 7.6 (IQR, 5.0-10.) (P < .001). These improvements exceeded the minimal clinically important difference. Instability accounted for most of the RSA complications; however, it did not account for any CTAH complications. The postoperative position of the center of rotation and greater tuberosity on anteroposterior radiographs did not correlate with the clinical outcomes for either procedure. CONCLUSION: For 103 patients with CTA, clinically significant improvement was achieved with appropriately indicated CTAH and RSA. In view of the lower cost of the CTAH implant, it may provide a cost-effective alternative to RSA for patients with retained active elevation.

Defining pseudoparalysis and pseudoparesis: a consensus study.

BACKGROUND: The purpose of this study was to establish consensus statements via a modified Delphi process on the definition of shoulder pseudoparalysis and pseudoparesis. METHODS: A consensus process on the definition of a diagnosis of pseudoparalysis utilizing a modified Delphi technique was conducted, and 26 shoulder/sports surgeons from 11 countries, selected based on their level of expertise in the field, participated in these consensus statements. Consensus was defined as achieving 80%-89% agreement, whereas strong consensus was defined as 90%-99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. RESULTS: Three statements regarding the diagnosis of pseudoparalysis reached strong (>89%) consensus: passive range of motion should be unaffected, the passive range of abduction should not be considered, and diagnosis should be excluded if lidocaine injection produces a substantial improvement in range of motion. Additionally, consensus (>79%) was reached that the active range of external rotation should not be considered for diagnosis, pain as a cause of restricted motion must be excluded, and that distinctions between restricted active flexion and external rotation should be made by range of motion rather than tear characteristics. No consensus could be reached on statements regarding the size, number of tendons or chronicity of cuff tears. Nor was there agreement on the active range of flexion permitted or on the difference between pseudoparalysis and pseudoparesis. CONCLUSION: A modified Delphi process was utilized to establish consensus on the definition of shoulder pseudoparalysis and pseudoparesis. Unfortunately, almost half of the statements did not reach consensus, and agreement could not be reached across all domains for a unifying definition for the diagnosis of pseudoparalysis in the setting of rotator cuff tears. Furthermore, it was not agreed how or whether pseudoparalysis should be differentiated from pseudoparesis. Based on the lack of a consensus for these terms, studies should report explicitly how these terms are defined when they are used.

Lateralization and distalization shoulder angles do not predict outcomes in reverse shoulder arthroplasty for cuff tear arthropathy.

BACKGROUND: In reverse shoulder arthroplasty (RSA), there are a plethora of measurements regarding implant lateralization and distalization to optimize the center of rotation. Two specific measurements known as the "lateralization shoulder angle" (LSA) and "distalization shoulder angle" (DSA) have been the recent focus of studies to assess their association with RSA and postoperative function. The aim of this study was to evaluate the prognostic clinical value of the LSA and DSA in a large cohort of patients with cuff tear arthropathy (CTA) who were treated with different RSA systems. METHODS: Two local shoulder arthroplasty registries were reviewed for all RSA patients documented to have undergone a radiologic assessment and complete 2-year follow-up examination. The main inclusion criterion was primary RSA in patients with CTA. Patients with either a complete teres minor tear, os acromiale, or acromial stress fracture reported between the time of surgery and the 24-month follow-up were excluded. Five RSA implant systems with 4 neck-shaft angles (NSAs) were assessed. The Constant score, Subjective Shoulder Value, and range of motion at 2 years were correlated with both the LSA and DSA assessed on 6-month anteroposterior radiographs. Linear and parabolic univariable regressions were calculated for both shoulder angles, for each prosthesis system, and for the entire patient cohort. RESULTS: Between May 2006 and November 2019, there were a total of 630 CTA patients who had undergone primary RSA. Of this large cohort of patients, 270 were treated with the Promos Reverse prosthesis system (NSA, 155°); 44, Aequalis Reversed II (NSA, 155°); 62, Lima SMR Reverse (NSA, 150°); 25, Aequalis Ascend Flex (NSA, 145°); and 229, Univers Revers (NSA, 135°). The mean LSA was 78° (standard deviation [SD], 10°; range, 6°-107°), and the mean DSA was 51° (SD, 10°; range, 7°-91°). The average Constant score at 24 months' follow-up was 68.1 points (SD, 13 points; range, 13-96 points). Neither the linear nor parabolic regression calculations for the LSA or DSA revealed significant associations with any of the clinical outcomes. CONCLUSION: Different patients may achieve different clinical outcomes despite having identical LSA and DSA values. There is no association between angular radiographic measurements and 2-year functional outcomes after RSA.

Reverse shoulder arthroplasty for patients with cuff tear arthropathy: do clinical outcomes differ by inlay vs. onlay design?

BACKGROUND: The influence of position of the humeral tray (inlay or onlay) on clinical outcomes in reverse shoulder arthroplasty (RSA) is a topic of debate. The purpose of this study was to compare clinical and radiographic outcomes of patients with cuff tear arthropathy treated with RSA systems with inlay or onlay humeral tray design, similar neck-shaft angles, and lateralized glenospheres. METHODS: This was a retrospective study of prospectively obtained data from 1 tertiary care center. We identified all patients who underwent primary RSA between 2009 and 2017 (N = 511). We included 102 patients with diagnosed cuff tear arthropathy treated with RSA prostheses with a lateralized glenosphere and 135° neck-shaft angle (with either an inlay or onlay humeral tray design) who had a minimum of 2 years of follow-up (mean, 44 months; range, 24-125 months). Sixty-three patients (62%) had an inlay humeral tray (inlay group) and 39 (38%) had an onlay tray (onlay group). All patients underwent preoperative and postoperative evaluations, including measures of patient-reported outcomes (PROs), shoulder range of motion (ROM) testing, and radiographic imaging. Clinical relevance of changes in PROs and ROM was evaluated using published values for minimal clinically important differences. RESULTS: The 2 groups did not differ by demographic characteristics except for a higher proportion of women in the inlay group (75%) than in the onlay group (56%) (P = .04). Preoperative PROs and ROM were not significantly different between groups. At final follow-up, PROs and ROM were not different between groups in terms of statistical significance or clinical relevance. We found no significant differences in the rate of baseplate loosening (inlay, 3.2% vs. onlay, 5.1%, P = .63), revision surgery (inlay, 0% vs. onlay 5.1%, P = .07), acromial stress fracture (inlay, 3.2% vs. onlay, 5.1%, P = .63), prosthesis dislocation (inlay, 0% vs. onlay, 2.6%, P = .20), or scapular notching (inlay, 21% vs. onlay, 7.7%, P = .08). CONCLUSION: At 2-year minimum follow-up, the position of the humeral tray in RSA prostheses (either inlay or onlay) for cuff tear arthropathy was not associated with PROs, shoulder ROM, or rates of complications, including baseplate loosening, acromial stress fracture, and scapular notching.

A scapular statistical shape model can reliably predict premorbid glenoid morphology in conditions of severe glenoid bone loss.

BACKGROUND: Knowledge of premorbid glenoid parameters at the time of shoulder arthroplasty, such as inclination, version, joint line position, height, and width, can assist with implant selection, implant positioning, metal augment sizing, and/or bone graft dimensions. The objective of this study was to validate a scapular statistical shape model (SSM) in predicting patient-specific glenoid morphology in scapulae with clinically relevant glenoid erosion patterns. METHODS: Computed tomography scans of 30 healthy scapulae were obtained and used as the control group. Each scapula was then virtually eroded to create 7 erosion patterns (Walch A1, A2, B2, B3, D, Favard E2, and E3). This resulted in 210 uniquely eroded glenoid models, forming the eroded glenoid group. A scapular SSM, created from a different database of 85 healthy scapulae, was then applied to each eroded scapula to predict the premorbid glenoid morphology. The premorbid glenoid inclination, version, height, width, radius of best-fit sphere, and glenoid joint line position were automatically calculated for each of the 210 eroded glenoids. The mean values for all outcome variables were compared across all erosion types between the healthy, eroded, and SSM-predicted groups using a 2-way repeated measures analysis of variance. RESULTS: The SSM was able to predict the mean premorbid glenoid parameters of the eroded glenoids with a mean absolute difference of 3° ± 2° for inclination, 3° ± 2° for version, 2 ± 1 mm for glenoid height, 2 ± 1 mm for glenoid width, 5 ± 4 mm for radius of best-fit sphere, and 1 ± 1 mm for glenoid joint line. The mean SSM-predicted values for inclination, version, height, width, and radius were not significantly different than the control group (P > .05). DISCUSSION: An SSM has been developed that can reliably predict premorbid glenoid morphology and glenoid indices in patients with common glenoid erosion patterns. This technology can serve as a useful template to visually represent the premorbid healthy glenoid in patients with severe glenoid bony erosions. Knowledge of the premorbid glenoid preoperatively can assist with implant selection, positioning, and sizing.

Stemless reverse humeral component neck-shaft angle has an influence on initial fixation.

BACKGROUND: Stemless anatomic humeral components are commonly used and are an accepted alternative to traditional stemmed implants in patients with good bone quality. Presently, little literature exists on the design and implantation parameters that influence primary time-zero fixation of stemless reverse humeral implants. Accordingly, this finite element analysis study assessed the surgical implantation variable of neck-shaft angle, and its effect on the primary time-zero fixation of reversed stemless humeral implants. METHODS: Eight computed tomography-derived humeral finite element models were used to examine a generic stemless humeral implant at varying neck-shaft angles of 130°, 135°, 140°, 145°, and 150°. Four loading scenarios (30° shoulder abduction with neutral forearm rotation, 30° shoulder abduction with forearm supination, a head-height lifting motion, and a single-handed steering motion) were employed. Implantation inclinations were compared based on the maximum bone-implant interface distraction detected after loading. RESULTS: The implant-bone distraction was greatest in the 130° neck-shaft angle implantation cases. All implant loading scenarios elicited significantly lower micromotion magnitudes when neck-shaft angle was increased (P = .0001). With every 5° increase in neck-shaft angle, there was an average 17% reduction in bone-implant distraction. CONCLUSIONS: The neck-shaft angle of implantation for a stemless reverse humeral component is a modifiable parameter that appears to influence time-zero implant stability. Lower, more varus, neck-shaft angles increase bone-implant distractions with simulated activities of daily living. It is therefore suggested that humeral head osteotomies at a higher neck-shaft angle may be beneficial to maximize stemless humeral component stability.

Disease diagnosis and arthroplasty type are strongly associated with short-term postoperative patient-reported outcomes in patients undergoing primary total shoulder arthroplasty.

BACKGROUND: Prognostic factors for total shoulder arthroplasty (TSA) clinical outcomes are incompletely understood. This study investigates the associations of preoperative patient, disease-specific, and surgical factors with 1-year postoperative PENN Shoulder Score (PSS) in patients undergoing primary TSA. METHODS: Cleveland Clinic patients undergoing primary anatomic TSA (aTSA) or reverse TSA (rTSA) for glenohumeral osteoarthritis (GHOA) or rotator cuff tear arthropathy (CTA) between February 2015 and August 2019, and having complete preoperative and 1-year postoperative patient-reported outcome measures (PROMs), were included. Twenty preselected preoperative patient, disease-specific, and surgical factors were used to fit multivariable models for 1-year PSS and its subscores. RESULTS: Of 1427 eligible primary TSAs, 1174 had 1-year follow-up by PROMs (82%), with 1042 analyzed after additional exclusions, including 30% rTSAs for CTA (n = 308), 26% rTSAs for GHOA (n = 275), and 44% aTSAs for GHOA (n = 459). All PROMs showed statistically significant improvements postoperatively, with 89% of patients reaching an acceptable symptom state. Lower 1-year PSS was associated with younger age, female sex, current smoking, chronic pain diagnosis, history of prior surgery, worker's compensation claim, lower preoperative mental health, lower baseline PSS, absence of glenoid bone loss, and diagnosis-arthroplasty type (CTA-rTSA < GHOA-rTSA < GHOA-aTSA). The most important prognostic factors associated with 1-year PSS were diagnosis-arthroplasty type, baseline mental health status, and insurance status. CONCLUSIONS: Disease diagnosis, arthroplasty type, and several other baseline factors are strongly and individually associated with PROMs following primary TSA, with patients undergoing aTSA for GHOA demonstrating the highest PROM scores at 1-year follow-up. Patient, disease-specific, and surgical factors can be used to guide postoperative prognosis following primary TSA for improved preoperative patient counseling regarding expected outcomes of these procedures.

Defining patient satisfaction after reverse total shoulder arthroplasty: a systematic review.

BACKGROUND: The prevalence of reverse total shoulder arthroplasty (rTSA) has grown rapidly. As indications for the procedure expand, the proportion of patients who have satisfactory outcomes after rTSA has not been well defined. This systematic literature review explores overall patient satisfaction after rTSA and defines patient satisfaction based on indication for surgery. METHODS: A literature search was performed for studies describing patient satisfaction after rTSA in accordance with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Papers were included if they investigated patient satisfaction after rTSA at a minimum of 2-year follow-up. Data were collected on patient demographics, including age, gender, and body mass index. Follow-up duration, indication for surgery, and patient reported outcome measures relating to patient satisfaction were also recorded. RESULTS: There were a total of 5234 patients and 5288 shoulders from the 45 included studies. The overall study population was 61.2% female and the average age was 71.1 years (range 23-99). Satisfaction results were recorded at final follow-up, with average follow-up of 49.1 months (range 24-228). Overall patient satisfaction ranged from 77.7% to 87.8%, depending on patient satisfaction patient reported outcome measures. When stratified by diagnosis, patients with a diagnosis of glenohumeral osteoarthritis (GHOA) rated better satisfaction on all metrics when compared to patients with a diagnosis of cuff tear arthropathy or massive rotator cuff tear. CONCLUSION: This systematic review demonstrated that patients who undergo rTSA for either GHOA, cuff tear arthropathy, or massive rotator cuff tear are generally satisfied with their procedure, with the rate of satisfaction highest in GHOA. Focusing on patient satisfaction may provide the best overall assessment of health care quality in a very understandable and tangible form. Overall satisfaction rate is valuable information for patient education and can be utilized as part of effective surgical counseling.

Superior Capsular Reconstruction using the Long Head of Biceps Tendon: A Biomechanical Assessment of Tenodesis Location and Angle of Fixation.

BACKGROUND: Massive irreparable rotator cuff tears (MIRCT) treated with superior capsular reconstruction (SCR) using the long head of the biceps tendon have shown satisfactory early results. Different techniques and positions for biceps tenodesis have been described. This study aimed to evaluate the effect of tenodesis location and glenohumeral fixation angle for graft tensioning on the biomechanics of a SCR using a single strand biceps technique. METHODS: Eight cadaveric shoulders were mounted to a custom biomechanical simulator which employed static tone loads to the deltoid and rotator cuff muscles. All cadavers were first tested in the intact condition, and then in the simulated MIRCT condition by sectioning the tendinous insertions of the supraspinatus and upper border of the infraspinatus. SCR using the long head of the biceps tendon was then evaluated. Three biceps tenodesis locations relative to the greater tuberosity (anterior, middle, and posterior) and two glenohumeral fixation angles (0° and 30°) for graft tensioning were tested. An optical tracking system was used to quantify superior-inferior (SI) and anterior-posterior (AP) humeral head translation relative to the glenoid, while the functional abduction force was quantified using a load sensor. All tests were conducted at 0°, 30° and 60° of glenohumeral abduction in a randomized fashion. RESULTS: When assessing isolated superior humeral head migration, all biceps tenodesis locations were effective at decreasing superior migration, with no tenodesis location significantly better than the other (P=0.213). However, biceps grafts tensioned at 30° of glenohumeral abduction were significantly better at reducing proximal humeral migration as compared to graft tensioning at 0° abduction (P=0.008). Posterior humeral head translation observed in the MIRCT condition was significantly reduced when tensioning the biceps tendon at 30° of glenohumeral abduction compared to 0° for all tenodesis locations (P≤0.043). Tenodesis location also significantly influenced posterior humeral head translation (P=0.001), with middle and posterior positions restoring near normal humeral head position when fixed at 30° glenohumeral abduction. All SCR techniques using the biceps tendon improved the functional abduction force relative to the MIRCT condition, although no statistically significant differences were observed relative to the intact condition (P≥0.448). DISCUSSION: SCR using the long head biceps tendon is biomechanically effective in reducing posterosuperior translation of the humeral head in the setting of a MIRCT. Graft tensioning and fixation at 30° of glenohumeral abduction combined with either a middle or posterior tenodesis location on the greater tuberosity most effectively restores near normal time-zero humeral head kinematics.

Instability after reverse shoulder arthroplasty: a retrospective review of thirty one cases.

PURPOSE: A retrospectively analyze of instability after RSA in terms of aetiology, treatment and final functional outcome. METHODS: A bicentric retrospective study of 31 patients (mean age 67.6 years; 42-83) treated for RSA instability using RSA Arrow System (FH Orthopedics, Mulhouse, France), mean follow-up 41months (range 12-158). Aetiologies for dislocation were evaluated using a previously described classification system for RSA instability. Actions performed during the Revision Surgeries were analyzed and grouped into five categories. Clinical outcome measures included range of motion, SSV, VAS, Constant-Murley scores, satisfaction level and recurrence of instability. RESULTS: The most frequent aetiology for RSA instability was loss of compression (18), followed by impingement (8) and loss containment (5). Total RSA revision (bipolar procedure) involving both distalization and lateralization occurred in 13 instances. Isolated distalization through the humerus was performed in ten patients and Isolated lateralization through the glenoid in three patients. Three cases of components exchange due to mechanical failure were noted. Bone graft was used in nine instances. Three patients (10%) suffered recurrent instability following Revision Surgery and required an additional stabilizing procedure. At final follow-up all 31 RSA were reported as stable with a mean VAS of 1.1, SSV 54.5%, constant score 48.3, constant ponderate 74.9%. CONCLUSION: The management of unstable RSA represent a challenge that can be successfully overcome with a revision surgery with compromised functional results. Loss of compression was the most common cause for primary and recurrent RSA instability that were treated principally with bipolar revisions involving component lateralization and distalization.

Neuropathy of the suprascapular and axillary nerves in rotator cuff arthropathy: a prospective electrodiagnostic study.

PURPOSE: Prevalence of axillary (AN) and/or suprascapular (SSN) neuropathy in rotator cuff tear arthropathy (RCTA) is unknown. We aimed to prospectively evaluate for preoperative neurodiagnostic abnormalities in order to determine their prevalence, location, and influence on reverse shoulder arthroplasty (RSA) outcomes. METHODS: Patients who underwent RSA for RCTA were prospectively included. An electromyography and nerve conduction study were performed pre and post-surgery. Clinical situation: VAS, Relative Constant-Murley Score (rCMS) and ROM over a minimum of two years follow-up. RESULTS: Forty patients met the inclusion criteria; mean follow-up was 28.4 months (SD 4.4). Injuries in RCTA were present in 83.9% (77.4% in AN and 45.2% in SSN). There were no differences on preoperative VAS, ROM, and rCMS between patients with and without preoperative nerve injuries. Four acute postoperative neurological injuries were registered under chronic preoperative injuries. Six months after RSA, 69% of preoperative neuropathies had improved (82.14% chronic injuries and 77.7% disuse injuries). No differences in improvement between disuse and chronic injuries were found, but patients with preoperative neuropathy that had not improved at the postoperative electromyographic study at six months, scored worse on the VAS (1.44 vs 2.66; p .14) and rCMS (91.6 vs 89.04; p .27). CONCLUSIONS: The frequency of axillary and suprascapular neuropathies in RCTA is much higher than expected. Most of these injuries improve after surgery, with almost complete neurophysiological recovery and little functional impact on RSA. However, those patients with preoperative neuropathies and absence of neurophysiological improvement six months after surgery have lower functional results.

The effects of length and width of the stem on proximal humerus stress shielding in uncemented primary reverse total shoulder arthroplasty.

INTRODUCTION: To preserve humeral bone during RTSA, stems have been made shorter and cement avoided whenever possible. However, with the increased use of uncemented RTSA, a phenomenon comparable to the stress shielding of the hip has been described for the proximal humerus. The aim of this study was to investigate the influence of stem length and width on proximal humeral bone resorption after primary uncemented RTSA. MATERIALS AND METHODS: The prospective shoulder arthroplasty database of our institution was reviewed for all primary uncemented RTSAs from 2017 to 2020 in osteoarthritis and cuff tear arthropathy cases with > 2-year follow-up. We compared the clinical and the radiographic 2-year outcome of the short and standard length stems of the same prosthesis design. This allowed us to assess the effects of stem length and width with regard to stress shielding. Furthermore, we defined a cut-off value for the filling ratios to prevent stress shielding. RESULTS: Fifty patients were included in the analysis, nineteen were in the short stem group (SHORT) and thirty-one in the standard stem group (STANDARD). After 2 years, SHORT showed a relative Constant Score of 91.8% and STANDARD of 98.3% (p = 0.256). Stress shielding was found in 4 patients (21%) in SHORT and in 16 patients (52%) in STANDARD (p = 0.03); it occurred more frequently in patients with higher humeral filling ratios (p < 0.05). The calculated cut-off to prevent stress shielding was 0.7 (± 0.03) for the metaphyseal and distal filling ratio. CONCLUSION: While short and standard stems for RTSA have good results after 2 years, we found a significant negative effect of higher length and width of the stem with regard to stress shielding. Even though the clinical effects of stress shielding have to be assessed, short stems should be chosen with a filling ratio at the metaphyseal and distal position below 0.7. LEVEL OF EVIDENCE (A RETROSPECTIVE CASE-CONTROL STUDY): III.

The acetabularization index: a novel measure of acromial bone loss prior to reverse shoulder arthroplasty.

BACKGROUND: Acromial stress fractures following reverse shoulder arthroplasty (RSA) have gained attention among specialized surgeons over the past decades craving answers regarding predisposing factors and technical aspects as how to avoid the complication. This study introduces the acetabularization index (AI) for the preoperative estimation of acromial bone loss attributed to acetabularization in cases of cuff tear arthropathy (CTA). METHODS: The acromiohumeral interval (AHI), extent of acromial acetabularization (AA), acromial height (AH), and width of acetabularization (r) were measured on preoperative radiographs and two-dimensional computed tomography scans (2D CT) of patients who underwent RSA within the timeline 2019-2023 for CTA. The AI calculated AI % = AA mm ÷ AH mm . The CTA grade was determined according to the Hamada classification. The AI values on radiographs and 2D CT were compared by a Student's t-test. Possible correlation between the AI and AHI was investigated via Pearson's coefficient. The intraclass correlation coefficient (ICC) was employed to test the interobserver reliability among two independent testers. RESULTS: The radiographs and 2D CT scans of thirty-three patients who underwent RSA were analyzed. The mean AHI, AH, AA, r, and AI values on radiographs were 5.5 ± 2 mm, 10 ± 2 mm, 2 ± 2 mm, 30 ± 4 mm, 16 ± 16%, respectively. On 2D CT, the corresponding mean values were 4.7 ± 2.5 mm, 10.8 ± 2.65 mm, 2.45 ± 2.35 mm, and 30 ± 4.5, and 22.3 ± 22%, respectively. There was a statistically significant difference between the AI values on radiographs and 2D CT (P = .000). The Pearson's correlation coefficient demonstrated a negative correlation between AI and AHI (r = - 0.33). Excellent reliability was observed by the ICC values for all parameters in both groups among two testers. CONCLUSION: The AI is a reliably measurable tool on radiographs and 2D CT scans; however, the measurements derived from radiographs vary significantly from CT based measurements due to projection restrictions. Grade IVB of the Hamada/Fukuda classification is associated with the highest AI values. Further research is warranted to assess the clinical utility of this index as a predictive tool for postoperative acromial stress fractures.

Incongruity of the scapulohumeral arch: an indirect sign of posterior subluxation of the humeral head in primary glenohumeral osteoarthritis.

BACKGROUND: In symptomatic glenohumeral osteoarthritis, arthroplasty is the gold standard to restore a mobile and painless shoulder. The kind of arthroplasty chosen is mainly based on the evaluation of the rotator cuff and the type of glenoid. The aim of this study was to analyze the scapulohumeral arch in primary glenohumeral osteoarthritis (PGHOA) with an uninjured cuff and to determine whether posterior humeral subluxation influences the Moloney line, which corresponds to an intact scapulohumeral arch. MATERIALS AND METHODS: Between 2017 and 2020, 58 anatomic total shoulder arthroplasties were implanted in the same center. We included all patients with complete preoperative imaging (radiographs and magnetic resonance imaging or arthro-computed tomography scans) assessing an intact rotator cuff. A total of 55 shoulders that had undergone surgery with a total anatomic shoulder prosthesis were analyzed after determination of the type of glenoid in the frontal plane according to the Favard classification on an anteroposterior radiograph and in the axial plane according to the Walch classification on computed tomography scans. The grade of osteoarthritis was evaluated according to the Samilson classification. We analyzed whether there was a rupture of the Moloney line on the frontal radiograph and assessed the acromiohumeral distance. RESULTS: After preoperative analysis of 55 shoulders, 24 shoulders had type A glenoids and 31 had type B glenoids. Scapulohumeral arch rupture was observed in 22 shoulders, and posterior subluxation of the humeral head was found in 31 shoulders, of which 25 had type B1 glenoids and 6 had type B2 glenoids according to the Walch classification. Most glenoids were type E0 (n = 47.85%). Incongruity of the Moloney line was more frequent in shoulders with type B glenoids (20 of 31 [65%]) than those with type A glenoids (2 of 24 [8%], P < .001). No patient with a type A1 glenoid (0 of 15) had a rupture of the Moloney line, and only 2 patients with a type A2 glenoid (2 of 9) had incongruity of the scapulohumeral arch. CONCLUSION: In PGHOA, rupture of the scapulohumeral arch seen on anteroposterior radiographs, also known as the Moloney line, may be an indirect sign of posterior humeral subluxation, corresponding to a type B glenoid per the Walch classification. Incongruity of the Moloney line may indicate a rotator cuff injury or posterior glenohumeral subluxation with an intact cuff in PGHOA.

The biomechanical effects of acromial fracture angulation in reverse total shoulder arthroplasty.

BACKGROUND: The biomechanical changes and treatment guidelines on acromial fracture after reverse shoulder arthroplasty (RSA) are still not well understood. The purpose of our study was to analyze the biomechanical changes with respect to acromial fracture angulation in RSA. METHODS: RSA was performed on 9 fresh-frozen cadaveric shoulders. An acromial osteotomy was performed on the plane extending from the glenoid surface to simulate an acromion fracture. Four conditions of acromial fracture inferior angulation were evaluated (0°, 10°, 20°, and 30° angulation). The middle deltoid muscle loading origin position was adjusted based on the position of each acromial fracture. The impingement-free angle and capability of the deltoid to produce movement in the abduction and forward flexion planes were measured. The length of the anterior, middle, and posterior deltoid was also analyzed for each acromial fracture angulation. RESULTS: There was no significant difference in the abduction impingement angle between 0° (61.8° ± 2.9°) and 10° angulation (55.9° ± 2.8°); however, the abduction impingement angle of 20° (49.3° ± 2.9°) significantly decreased from 0° and 30° angulation (44.2° ± 4.6°), and 30° angulation significantly differed from 0° and 10° (P < .01). On forward flexion, 10° (75.6° ± 2.7°), 20° (67.9° ± 3.2°), and 30° angulation (59.8° ± 4.0°) had a significantly decreased impingement-free angle than 0° (84.2° ± 4.3°; P < .01), and 30° angulation had a significantly decreased impingement-free angle than 10°. On analysis of glenohumeral abduction capability, 0° significantly differed (at 12.5, 15.0, 17.5, and 20.0N) from 20° and 30°. For forward flexion capability, 30° angulation showed a significantly smaller value than 0° (15N vs. 20N). As acromial fracture angulation increased, the middle and posterior deltoid muscles of 10°, 20°, and 30° became shorter than those of 0°; however, no significant change was found in the anterior deltoid length. CONCLUSIONS: In acromial fractures at the plane of glenoid surface, 10° inferior angulation of the acromion did not interfere with abduction and abduction capability. However, 20° and 30° of inferior angulation caused prominent impingement in abduction and forward flexion and reduced abduction capability. In addition, there was a significant difference between 20° and 30°, suggesting that not only the location of the acromion fracture after RSA but also the degree of angulation are important factors for shoulder biomechanics.

Disparities in arthroplasty utilization for rotator cuff tear arthropathy.

BACKGROUND: Rotator cuff tear arthropathy (CTA) carries a significant symptomatic burden for patients. Reverse shoulder arthroplasty (RSA) is an effective treatment intervention for CTA. Disparities in musculoskeletal medicine are well documented; however, there is a paucity of literature on how social determinants of health affect utilization rates. The purpose of this study is to determine how social determinants of health affect the utilization rates of RSA. METHODS: A single-center retrospective review was conducted for adult patients diagnosed with CTA between 2015 and 2020. Patients were divided by those who underwent RSA and those who were offered RSA but did not undergo surgery. Each patient's zip code was used to determine the most specific median household income in the US Census Bureau database and compared to the multistate metropolitan statistical area median income. Income levels were defined by the US Department of Housing and Urban Development's (HUD's) 2022 Income Limits Documentation System and the Federal Reserve's (FED's) Community Reinvestment Act. Because of numeric restrictions, patients were grouped into racial cohorts of Black, White, and all other races. RESULTS: Patients of other races had significantly lower odds of continuing to surgery compared with White patients in models controlled for median household income (odds ratio [OR] 0.38, 95% confidence interval [CI] 0.18-0.81, P = .01), HUD's 3 income levels (OR 0.36, 95% CI 0.18-0.74, P = .01), and FED's income levels (OR 0.37, 95% CI 0.17-0.79, P = .01). There was no significantly different odds of going on to surgery between FED income levels and median household income levels, but when compared with those with low HUD income, those below median had significantly lower odds of going on to surgery (OR 0.43, 95% CI 0.23-0.80, P = .01). CONCLUSION: Although contradictory to reported health care utilization for Black patients, our study supports reported disparities in utilization for other ethnic minorities. These findings may suggest that improvements in utilization efforts targeted Black-identifying patients but not necessarily other ethnic minorities. The findings of this study can help providers understand how social determinants of health play a role in the utilization of care for CTA and direct mitigation efforts to reduce disparities in access to adequate orthopedic care.

Relationship between the preoperative grip strength and postoperative shoulder strength of patients treated via reverse shoulder arthroplasty.

BACKGROUND: Systemic disorders including diabetes mellitus, obesity, and depression affect the outcomes of reverse shoulder arthroplasty (RSA). Sarcopenia (a general skeletal muscle disorder) is common in elderly people, but its effect on patients after RSA is not clear. We hypothesized that the preoperative sarcopenia indices of grip strength and general skeletal muscle mass would correlate with the clinical outcomes of RSA. METHODS: Grip strength and general skeletal muscle mass were measured in patients scheduled (between 2016 and 2021) for primary RSA to treat cuff tear arthropathy, an unrepairable cuff tear, or osteoarthritis with a large cuff tear. Before surgery, grip strength was measured using a hydraulic dynamometer and general skeletal muscle mass was calculated from the appendicular relative skeletal muscle mass index (aRSMI) using dual-energy X-ray absorptiometry. In all, 58 patients were included; the minimal follow-up duration was 12 months. The postoperative clinical results (pain, active range of motion, shoulder strength, and functional scores) were evaluated during scheduled outpatient visits. We calculated correlations between the preoperative sarcopenia indices, and the clinical results at the final follow-up. RESULTS: The mean preoperative grip strength and aRSMI were 21.6 ± 4.0 kg and 5.98 ± 0.84 kg/m2 in females and 30.6 ± 7.5 kg and 7.21 ± 0.94 kg/m2 in males, respectively; the grip strength and aRSMI were not associated with each other (P = .083). Ten females (25%) and 10 males (56%) met the criteria for sarcopenia. The postoperative abduction shoulder strength and Constant-Murley shoulder score increased significantly with higher preoperative grip strength (R = 0.420 and P = .001; and R = 0.497 and P < .001, respectively) and the American Shoulder and Elbow Surgeons score was related to the preoperative aRSMI (R = 0.320, P = .039). CONCLUSIONS: The shoulder strength and functional score after RSA correlated positively with the preoperative grip strength. Measuring grip strength before RSA allows the surgeon to predict shoulder strength after RSA.

Indication matters: effect of indication on clinical outcome following reverse total shoulder arthroplasty-a multicenter study.

BACKGROUND: As the utilization and success of reverse total shoulder arthroplasty (RTSA) have continued to grow, so have its surgical indications. Despite the adoption of RTSA for the treatment of glenohumeral osteoarthritis (GHOA) with an intact rotator cuff and irreparable massive rotator cuff tears (MCTs) without arthritis, the literature remains sparse regarding the differential outcomes after RTSA among these varying indications. Thus, the purpose of this study was to examine the postoperative clinical outcomes of RTSA based on indication. METHODS: A retrospective review of 2 large institutional databases was performed to identify all patients who underwent RTSA between 2015 and 2019 with minimum 2-year follow-up. Patients were stratified by indication into 3 cohorts: GHOA, rotator cuff tear arthropathy (CTA), and MCT. Baseline demographic characteristics were collected to determine differences between the 3 cohorts. Clinical outcomes were measured preoperatively and postoperatively, including active range of motion, American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numeric Evaluation score, and visual analog scale pain score. Multivariate linear regression was performed to determine the factors independently predictive of the postoperative ASES score. RESULTS: A total of 625 patients (383 with GHOA, 164 with CTA, and 78 with MCTs) with a mean follow-up period of 33.4 months were included in the analysis. Patients with GHOA had superior ASES scores (85.6 ± 15.7 vs. 76.6 ± 20.8 in CTA cohort [P < .001] and 75.9 ± 19.9 in MCT cohort [P < .001]), Single Assessment Numeric Evaluation scores (86 ± 20.9 vs. 76.7 ± 24.1 in CTA cohort [P < .001] and 74.2 ± 25.3 in MCT cohort [P < .001]), and visual analog scale pain scores (median [interquartile range], 0.0 [0.0-1.0] vs. 0.0 [0.0-2.0] in CTA cohort [P < .001] and 0.0 [0.0-2.0] in MCT cohort [P < .001]) postoperatively. Postoperative active forward elevation (P < .001) and improvement in active external rotation (P < .001) were greatest in the GHOA cohort compared with other indications. Multivariate linear regression demonstrated that the factors independently associated with the postoperative ASES score included a diagnosis of GHOA (ß coefficient, 7.557 [P < .001]), preoperative ASES score (ß coefficient, 0.114 [P = .009]), female sex (ß coefficient, -4.476 [P = .002]), history of surgery (ß coefficient, -3.957 [P = .018]), and postoperative complication (ß coefficient, -13.550 [P < .001]). CONCLUSION: RTSA for the treatment of GHOA generally has superior patient-reported and functional outcomes when compared with CTA and MCTs without arthritis. Long-term follow-up is needed to identify the lasting implications of such outcome differences.