Humeral rotation osteotomy is not associated with glenohumeral and scapulohumeral decentering at long-term follow-up.

BACKGROUND: Weber rotational osteotomy that increases humeral retrotorsion in patients with anterior shoulder instability has become unpopular because of recurrence of instability and high rates of early-onset osteoarthritis (OA). However, the wear pattern in patients after rotational osteotomy remains unknown. The aim of this study was to determine the influence of surgically increased humerus retrotorsion on glenohumeral and scapulohumeral centering in a long-term follow-up. METHODS: The data of 18 shoulders in 18 patients diagnosed with a unilateral chronic recurrent anterior shoulder instability treated with an internal rotation subcapital humerus osteotomy between 1984 and 1990 were drawn from a previously published cohort and enrolled in the study. All patients had available bilateral computed tomography (CT) scans performed after a mean follow-up of 14 (12-18) years. On these CT scans a comparison of the operated and the contralateral healthy side with regard to humerus torsion, glenoid version, glenoid offset, glenohumeral and scapulohumeral subluxation indices, rotator cuff action lines, and osteoarthritic changes was performed. RESULTS: The analysis of follow-up CT scans revealed a significantly higher mean humeral retrotorsion in the operated side compared with the healthy side (41.6° ± 14.0° vs. 20.7° ± 8.2°, P < .001). No differences were found in terms of glenohumeral subluxation index (0.50 ± 0.08 vs. 0.51 ± 0.03, P = .259), scapulohumeral subluxation index (0.53 ± 0.09 vs. 0.54 ± 0.03, P = .283), glenoid version (-3.9° ± 4.6° vs. -4.1° ± 3.7°, P = .424), glenoid offset (4.0 ± 2.8 mm vs. 4.0 ± 1.3 mm, P = .484), infraspinatus action lines (102.5° ± 4.7° vs. 101.2° ± 2.1°, P = .116), subscapularis action lines (74.0° ± 6.0° vs. 73.1° ± 2.3°, P = .260), and resultant rotator cuff action lines (87.8° ± 4.9° vs. 87.0° ± 1.8°, P = .231) between operated and healthy shoulders. Osteoarthritic changes were observed in all operated shoulders and in 13 of 18 healthy shoulders. The OA grade was mild in 5 patients, moderate in 11, and severe in 2 cases for operated shoulders and mild in 13 healthy shoulders at the last follow-up. CONCLUSION: The surgical increase of humeral retrotorsion by 20°-30° did not affect glenohumeral and scapulohumeral centering in patients with a Weber rotational osteotomy after a long-term follow-up compared to the healthy side. Although a high degree of early-onset OA was observed it remains unclear whether the cause is the surgical interventions performed or the joint instability itself.

Utility of Patient Reported Outcome Measurement Information System measures in predicting shoulder arthroplasty in patients with shoulder osteoarthritis.

BACKGROUND: The decision to treat shoulder osteoarthritis (OA) definitively with shoulder arthroplasty (SA) is multifactorial, considering objective findings, subjective information, and patient goals. The first goal of this study was to determine if Patient Reported Outcome Measurement Information System (PROMIS) measures correlated with patients with shoulder OA who underwent SA within 1 year. The second goal of this study was to determine if score cut-offs in PROMIS domains could further discriminate which shoulder OA patients underwent SA within 1 year. METHODS: This retrospective case-control study examined patients with a diagnosis of shoulder OA who consulted an orthopedic provider from November 1, 2020 to May 23, 2022, and recorded PROMIS measures in the domains of Physical Function, Depression, and/or Pain Interference. A surgical group was defined as patients who underwent SA within 1 year of the most recent PROMIS measures and the nonsurgical patients were defined as the control group. Mean PROMIS scores were compared between the surgical and control groups. Separate logistic regression models controlling for age, race, ethnicity, and comorbidity count were performed for each PROMIS domain as a 1) continuous variable, and then as 2) binary variable defined by PROMIS score cut-off points to determine which scores correlated with undergoing SA to further characterize the potential clinical utility of PROMIS score cut-offs in relating to undergoing SA. RESULTS: The surgical group of 478 patients was older (68.2 vs. 63.8 years), more often of White race (82.6% vs. 70.9%), and less often of Hispanic Ethnicity (1.5% vs. 2.9%) than the control group of 3343 patients. Using optimal cut-offs in PROMIS scores, Pain Interference ≥63 (odds ratio [OR] = 2.97 (2.41-3.64), P < .001), Physical Function ≤39 (OR = 1.81 (95% confidence interval, 1.48-2.22), P < .001), and depression ≥49 (OR = 1.82 (95% confidence interval, 1.50-2.22), P < .001) were all found to correlate with undergoing SA within 1 year in multivariable logistic regressions. CONCLUSION: The results of this study demonstrate that cut-off scores for PROMIS measures differentiated patients undergoing SA within 1 year. These cut-off scores may have clinical utility in aiding in decision-making regarding surgical candidates for SA. Further research is needed to validate these cut-off scores and determine how they relate to patient outcomes after SA.

Outcomes of Corrective, Concentric (C2) Glenoid Reaming combined with Pyrocarbon Hemiarthroplasty for B2, B3 Glenoid Arthritis.

BACKGROUND: Posterior humeral subluxation (PHS) in B2/B3 glenoid is a cause of asymmetric long-term stress on the glenoid and the potential reason for glenoid loosening in anatomic total shoulder arthroplasty (ATSA) and painful glenoid erosion in hemiarthroplasty with metallic heads (HA-Metal). We hypothesized that corrective and concentric reaming (CCR) of the glenoid associated with pyrocarbon hemiarthroplasty (HA-PYC) could improve the centering of the humeral head and decrease the risk of persistent painful glenoid erosion in young/active patients with B2/B3 glenoid. METHODS: Between 2014 and 2020, 41shoulders (in 35 patients, mean age of 57.9 years) underwent HA-PYC combined with CCR reaming for B2 (n=30) or B3 (n=11) osteoarthritis. Patients were prospectively followed with computed tomography (CT) scans performed preoperatively, immediate postoperatively and at last follow-up (> 2 years). The primary outcomes were 3D-corrected CT-scan measurements of glenoid version, PHS, progression of glenoid erosion. Secondary outcomes included functional outcome scores, return to activities, and revision rate and complications. RESULTS: At a mean follow-up of 4.5 years (2 to 9.5 years), the prosthesis survival was 95% (39/41). No patient has been reoperated for painful glenoid erosion. The mean glenoid retroversion decreased from 17.1° ± 7.5 preoperatively to 8.3° ± 8.2 at last follow-up (p=0.001), and the mean PHS from 74% to 56.5% (p=0.001) based on the scapular plane and from 59.9% to 50.3% based on the glenoid plane. The humeral head was recentered in 97% according to the glenoid surface and 71% according to the scapular plane. Correction of PHS in the scapular plane was highly correlated to correction of glenoid retroversion (p<0.001). CT-scan measurements showed that the average total medialization was 3.7 ± 3.2 mm (2.0 ± 1.8 mm due to reaming and only 1.7 ± 2.4 mm due to erosion). The Adjusted Constant score increased from 43% ± 13 to 97% ± 16 and the Subjective Shoulder Value from 38% ± 14 to 84 % ± 12 (p<0.001). Overall, 84% of active patients returned to work and all patients returned to sports. CONCLUSION: In B2/B3 glenoid arthritis, corrective, concentric glenoid reaming combined with HA-PYC improves centering of the humeral head and shows a low risk of painful glenoid erosion at mid-term follow-up. The combined procedure results in excellent functional outcomes and high prosthesis survivorship at mid-term follow-up. HA-PYC and CCR is offering an alternative shoulder arthroplasty for young/active patients with B2/B3 glenoid osteoarthritis who want to return to work or sports practice.

Survey of Osteoarthritis of the Shoulder in Patients who Underwent Knee Arthroplasty for Knee Osteoarthritis.

The relationship between osteoarthritis (OA) of the lower extremity and shoulder OA has not been established. This study evaluated the prevalence of shoulder OA in patients with knee OA. We collected contrast-enhanced computed tomography (CECT) images of the shoulder joints of 105 patients with knee OA that were taken 1 week after they underwent primary knee arthroplasty to check for venous thromboembolism (VTE). The images were compared with CECT images of 110 control-group patients that were taken for the purpose of differentiating VTE. Shoulder OA was present in a significantly higher percentage of patients with knee arthroplasty than controls (29% versus 15%), and the difference was particularly pronounced in patients in their 70s (33%) compared to age-matched controls (11%). Patients with knee OA often use arm support to stand up or walk due to knee joint pain and muscle weakness, which places the weight-bearing shoulder at risk of developing OA.

Obesity is associated with an increased risk of undergoing shoulder arthroplasty in Australia.

BACKGROUND: The aim of this study was to examine the incidence of overweight and obesity in patients undergoing primary total shoulder arthroplasty (TSA) for osteoarthritis (OA) in Australia compared to the incidence of obesity in the general population. MATERIALS AND METHODS: A 2017/18 cohort consisting of 2997 patients from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) who underwent TSA were compared with matched controls from the Australian Bureau of Statistics (ABS) National Health Survey from the same time period. The 2 groups were analyzed according to body mass index (BMI) category, sex, and age. RESULTS: According to the 2017/18 National Health Survey, 35.6% of Australian adults were overweight and 31.3% were obese. Of the primary TSA cases performed, 34.9% were overweight and 50.1% were obese. The relative risk of requiring TSA for OA increased with increasing BMI category. Class III obese females, aged 55-64, were 8.6 times more likely to receive a TSA compared to their normal weight counterparts. Males in the same age and BMI category were 2.5 times more likely. Class III obese patients underwent TSA 4 years (female) and 6 years (male) younger than their normal weight counterparts. CONCLUSION: Obesity significantly increases the risk of requiring TSA. The association appears to be particularly strong for younger females.

BIO-RSA vs. metal-augmented baseplate in shoulder osteoarthritis with multiplanar glenoid deformity: a comparative study of radiographic findings and patient outcomes.

BACKGROUND: Reverse shoulder arthroplasty (RSA) requiring extensive reaming to address severe glenoid bone loss increases the risk of glenoid medialization and baseplate failure. We hypothesized that (1) metal-augmented baseplate prevents the medialization of the joint line and preserves glenoid bone stock similarly to bony increased-offset (BIO)-RSA and (2) bone graft viability and healing in BIO-RSA patients become compromised over time. MATERIALS AND METHODS: Eighty-one patients (83 shoulders) underwent glenoid lateralization with bone (BIO-RSA group, 44) or metal-augmented baseplate (metallic increased-offset [MIO]-RSA group, 39) and a minimum follow-up of 24 months were included. The orientation and direction of glenoid erosion was identified and recorded using computerized 3D planning. Active range of motion, and the Western Ontario Osteoarthritis of the Shoulder (WOOS) index were assessed before arthroplasty and at the last follow-up visits. Radiographic changes around the glenoid and humeral components were assessed. Healing and thickness of bone graft were evaluated by predefined criteria. Postoperative global glenoid inclination (ß angle) and retroversion were also measured. RESULTS: Delta scores of active anterior elevation were higher in the MIO-RSA group (P = .027). The differences in the other planes of shoulder motion and in WOOS index scores between the groups were not significant. Preoperative glenoid retroversion was higher in BIO-RSA patients, and glenoid inclination was similar in both groups. Type B2 and B3 glenoids had a posterior-central (91%) and posterior-superior (90%) erosion with a mean posterior humeral head subluxation of 76% and 78%, respectively. The direction of erosion in type E2 and E3 glenoids was posterior-superior, with a mean posterior humeral head subluxation of 74%. The rate of high position of the glenosphere was higher in the BIO-RSA group (P = .022), whereas the values of ß angle and postoperative retroversion were similar in the 2 groups. BIO-RSA group showed radiolucent lines <2 mm around the bone graft in 16 patients (36.4%) and decreased thickness in 15 (34.1%). Incomplete baseplate seating was found in 4 MIO-RSA patients (10%). We found higher rates of humerus condensation lines in MIO-RSA patients (P = .01) and higher rates of cortical thinning and tuberosity resorption in the BIO-RSA group (P = .027 and P = .004, respectively). CONCLUSION: Metal-augmented glenoid is a suitable alternative to BIO-RSA to preserve bone and prevent the medialization of the joint line in arthritic glenoid with multiplanar glenoid deformity. Bone and metal augmentation provided satisfactory clinical outcomes. Bone graft resorption in BIO-RSA patients raise concern about the risk of baseplate loosening and requires further long-term studies.

Survey of Shoulder Osteoarthritis in Patients who Underwent Total Hip Arthroplasty for Hip Osteoarthritis.

To the best of our knowledge, no previous studies have reported a relationship between osteoarthritis (OA) of the lower limbs and OA of the shoulder joints. We evaluated the correlation between shoulder OA and hip OA. We collected contrast-enhanced computed tomography (CECT) images of the shoulder joints of 159 patients with hip OA who underwent primary total hip arthroplasty (THA). The images, taken 1 week after THA to monitor venous thromboembolism (VTE), were used to examine the prevalence of shoulder OA. They were compared with those of 103 controls who underwent CECT during the same period to monitor VTE. Shoulder OA was observed in 15% of the controls and 24% of the THA patients. Although the rate was somewhat higher in the THA group, the difference was not significant. However, in the THA group, significantly more patients with bilateral hip OA (33%) had shoulder OA than those with unilateral hip OA (17%). In summary, the prevalence of shoulder OA was significantly higher in patients with bilateral hip OA. In these patients, pain and instability in the hip joints require them to use arm support to stand up or walk, putting the weight-bearing shoulder at risk of developing OA.

Low grade of osteoarthritis development after Latarjet procedure with a minimum 5 years of follow-up: a systematic review and pooled analysis.

PURPOSE: The purpose of this systematic review and pooled analysis was to evaluate incidence and risk factors for glenohumeral osteoarthritis (OA) in patients who underwent Latarjet procedure with a minimum of 5-year follow-up. METHODS: The PRISMA guidelines were followed to perform this systematic review. PubMed and EMBASE were searched up to February 29, 2020 for English, human in vivo studies that evaluated glenohumeral OA in patients undergoing Latarjet procedure at least 5 years after surgery. A pooled analysis on the included databases sent by authors was performed to evaluate the risk factors influencing the development or progression of dislocation arthropathy after the Latarjet procedure. RESULTS: Four studies, including a total of 280 patients (213 males and 67 females), were analysed. In our study population, the median age at surgery was 25.0 years (range 20.8-32.6 years). and 92.1% were athletes. In 90% of the cases, the number of dislocations before surgery were fewer than 5. The recurrence of instability after Latarjet procedure was observed only in seven patients (2.5%). The position of the bone graft resulted flush to the anterior glenoid rim in 238 cases (85.3%), medial in 8 (2.9%) and overhanging in 33 (11.8%). Radiological signs of development or progression of shoulder OA were observed in 25.8% of the patients, of which 88.6% presented a grade 1 of OA according to Samilson and Prieto classification. The overhanging position of the bone graft resulted statistically significant for onset or worsening of OA. The age at surgery, the number of dislocations before surgery and the Hill-Sachs lesion were not significantly associated with joint degeneration. Instead, hyperlaxity showed a prevention role in the development of OA after open Latarjet procedure. CONCLUSION: The Latarjet procedure is a valid and safe surgical treatment in recurrent anterior shoulder instability with a low risk of developing moderate or severe OA also at long-term follow-up. The overhanging position of the bone graft represents the principal risk factor of joint degeneration, whereas the hyperlaxity seems to be protective. Finally, age, gender, time between first dislocation and surgery, and number of dislocations do not seem to affect the onset of OA after Latarjet procedure. Therefore, an accurate execution of the Latarjet procedure can be considered a valid treatment even in young and athletes thanks to the low recurrence rates and the low development of major long-term complications. LEVEL OF EVIDENCE: IV.

Total shoulder replacement stems in osteoarthritis-short, long, or reverse? An analysis of the impact of crosslinked polyethylene.

BACKGROUND: The 2021 Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) report indicated that total shoulder replacement using both midhead (TMH) length humeral components and reverse arthroplasty (RTSA) had a lower revision rate than stemmed humeral components in anatomic total shoulder arthroplasty (aTSA)-for all prosthesis types and diagnoses. However, there are many factors that affect the outcome of total shoulder replacement, including stem length and polarity, polyethylene type, and glenoid fixation (cemented vs. cementless). The aim of this study was to assess the impact of these variables in the various primary total arthroplasty alternatives for osteoarthritis (OA) in the shoulder. METHODS: Data from a large national arthroplasty registry were analyzed for the period April 2004 to December 2020. The study population included all primary aTSA, RTSA, and TMH shoulder arthroplasty procedures undertaken for OA using either crosslinked polyethylene (XLPE) or noncrosslinked polyethylene (non-XLPE). Because of the previously documented and reported higher revision rate compared with other anatomic total shoulder replacement options, those using cementless metal-backed glenoid components were excluded. The rate of revision was determined by Kaplan-Meier estimates, with comparisons by Cox proportional hazard models. Reasons for revision were also assessed. RESULTS: For a primary diagnosis of OA, aTSA with a cemented XLPE glenoid component had the lowest revision rate, with a 12-year cumulative revision rate of 4.7%, compared with aTSA with cemented non-XLPE glenoid component at 8.7% and RTSA at 6.8%. The revision rate for TMH (with XLPE or non-XLPE) was lower than aTSA with cemented non-XLPE but was similar to the other implants at the same length of follow-up. The reason for revision of cemented aTSR was most commonly component loosening, not rotator cuff deficiency. CONCLUSION: Long-stem humeral components matched with XLPE in aTSA achieve a lower revision rate compared with shorter stems, long stems with conventional polyethylene, and RTSA when used to treat shoulder OA. In all these cohorts, loosening, not rotator cuff failure, was the most common diagnosis for revision.

Does the osteoarthritic shoulder have altered rotator cuff vectors with increasing glenoid deformity? An in silico analysis.

BACKGROUND: A transverse force couple (TFC) functional imbalance has been demonstrated in osteoarthritic shoulders by recent 3-dimensional (3D) muscle volumetric studies. Altered rotator cuff vectors may be an additional factor contributing to a muscle imbalance and the propagation of glenoid deformity. METHODS: Computed tomography images of 33 Walch type A and 60 Walch type B shoulders were evaluated. The 3D volumes of the entire subscapularis, supraspinatus, and infraspinatus-teres minor (ISP-Tm) and scapula were manually segmented. The volume masks and scapular landmarks were imported into MATLAB to create a coordinate system, enabling calculation of muscle force vectors. The direction of each muscle force vector was described in the transverse and vertical plane, calculated with respect to the glenoid. Each muscle vector was then resolved into compression and shear force across the glenoid face. The relationship between muscle force vectors, glenoid retroversion or inclination, compression/shear forces on the glenoid, and Walch type was determined using linear regression. RESULTS: In the transverse plane with all rotator cuff muscles combined, increasing retroversion was significantly associated with increasing posterior drag (P < .001). Type B glenoids had significantly more posterior drag than type A (P < .001). In the vertical plane for each individual muscle group and in combination, superior drag increases as superior inclination increases (P < .001). Analysis of individual muscle groups showed that the anterior thrust of ISP-Tm and supraspinatus switched to a posterior drag at 8° and 10° of retroversion respectively. The compression force on the glenoid face by ISP-Tm and supraspinatus did not change with increasing retroversion for type A shoulders (P = .592 and P = .715, respectively), but they did for type B shoulders (P < .001 for both). The glenoid shear force ratio in the transverse plane for the ISP-Tm and supraspinatus moved from anterior to posterior shear with increasing glenoid retroversion, crossing zero at 8° and 10° of retroversion, whereas the subscapularis exerted a posterior shear force for every retroversion angle. CONCLUSION: Increased glenoid retroversion is associated with increased posterior shear and decreased compression forces on the glenoid face, explaining some of the pathognomonic bone morphometrics that characterize the osteoarthritic shoulder. Although the subscapularis always maintains a posterior thrust, the ISP-Tm and supraspinatus together showed an inflection at 8° and 10° of retroversion, changing from an anterior thrust to a posterior drag. This finding highlights the importance that in anatomic TSA the rotator cuff functional balance might be better restored by correcting glenoid retroversion to less than 8°.

Predictors of poor and excellent outcomes after reverse total shoulder arthroplasty.

BACKGROUND: Favorable clinical and functional outcomes can be achieved with reverse total shoulder arthroplasty (RSA). Given the expanding utilization of RSA in the United States, understanding the factors that influence both excellent and poor outcomes is increasingly important. METHODS: A single-surgeon prospective registry was used to identify patients who underwent RSA from 2015 to 2018 with a minimum of 2 years' follow-up. An excellent postoperative clinical outcome was defined as a final American Shoulder and Elbow Surgeons (ASES) score in the top quartile of ASES scores. A poor outcome was defined as an ASES score in the bottom quartile. Logistic regression was used to determine preoperative characteristics associated with both excellent and poor outcomes. RESULTS: A total of 338 patients with a mean age of 71.5 years (standard deviation [SD], 6.4 years) met the inclusion and exclusion criteria. The average preoperative ASES score for the entire cohort was 35.3 (SD, 16.4), which improved to 82.4 (SD, 16.1) postoperatively (P < .001). Univariate analysis demonstrated that a diagnosis of primary osteoarthritis (OA), private insurance, and higher preoperative ASES scores were significantly associated with achieving excellent outcomes (P < .01 for all). Variables predictive of poor outcomes were workers' compensation status (P = .03), depression (P = .02), a preoperative diagnosis of rotator cuff tear arthropathy (P < .01), preoperative opioid use (P < .01), a higher number of allergies (P < .01), and prior ipsilateral shoulder surgery (P < .01). Multivariate regression analysis demonstrated that OA (odds ratio [OR], 5.6; 95% confidence interval [CI], 1.2-26.5; P = .03) and private insurance (OR, 2.7; 95% CI, 1.12-6.5; P = .02) correlated with excellent outcomes whereas a higher number of reported allergies (OR, 0.83; 95% CI, 0.71-0.97; P = .02), self-reported depression (OR, 0.39; 95% CI, 0.16-0.99; P =.04), a history of ipsilateral shoulder surgery (OR, 0.36; 95% CI, 0.15-0.87; P =.02), and preoperative opioid use (OR, 0.26; 95% CI, 0.09-0.76; P = .01) were predictive of poor outcomes. CONCLUSIONS: A preoperative diagnosis of primary OA is the strongest predictor of excellent clinical outcomes following RSA. Patients with an increasing number of reported allergies, self-reported depression, a history of ipsilateral shoulder surgery, and preoperative opioid use are significantly more likely to achieve poor outcomes after RSA. Given the increasing utilization of RSA, this information is important to appropriately counsel patients regarding postoperative expectations.

Shoulder structure and function: The impact of osteoarthritis and rehabilitation strategies.

STUDY DESIGN: Invited review. BACKGROUND: Shoulder osteoarthritis can result in significant functional deficits. To improve diagnosis and treatment, we must better understand the impact of osteoarthritis on shoulder biomechanics and the known mechanical benefits of currently available treatments. PURPOSE: The purpose of this paper is to present up-to-date data on the effects of osteoarthritis and rehabilitation on the biomechanical parameters contributing to shoulder function. With this goal, we also reviewed the anatomy and the ranges of motion of the shoulder. METHODS: A search of electronic databases was conducted. All study designs were included to inform this qualitative, narrative literature review. RESULTS: This review describes the biomechanics of the shoulder, the impact of osteoarthritis on shoulder function, and the treatment of shoulder osteoarthritis with an emphasis on rehabilitation. CONCLUSIONS: The shoulder is important for the completion of activities of daily living, and osteoarthritis of the shoulder can significantly reduce shoulder motion and arm function. Although shoulder rehabilitation is an integral treatment modality to improve pain and function in shoulder osteoarthritis, few high-quality studies have investigated the effects and benefits of shoulder physical and occupational therapies. To advance the fields of therapy and rehabilitation, future studies investigating the effects of therapy intensity, therapy duration, and the relative benefits of therapy subtypes on shoulder biomechanics and function are necessary.

Determination of predisposing scapular anatomy with a statistical shape model-Part II: shoulder osteoarthritis.

HYPOTHESIS AND BACKGROUND: Shoulder osteoarthritis can be divided into different glenoid types (A, B, C, and D) and subtypes. The aim of this study was to investigate if there is an association between the prearthropathy scapular anatomy, shoulder osteoarthritis, and different glenoid types and subtypes. METHODS: Using principal components analysis, a statistical shape model (SSM) of the scapula was constructed from a data set of 110 computed tomographic (CT) scans. These subjects formed the control group. Next, CT scan images of 117 patients with osteoarthritis were classified according to the modified Walch classification. A complete 3-dimensional (3D) scapular bone model was created for every patient, and using the SSM, a reconstruction of their prearthropathy scapular anatomy was performed. Automated 3D measurements were performed in both the patient and control group to obtain glenoid version and inclination, critical shoulder angle (CSA), posterior acromial slope (PAS), lateral acromion angle, scapular offset, and the rotational alignment of the coracoacromial complex. These parameters were compared between controls, patients with osteoarthritis, and glenoid types and subtypes. RESULTS: Mean version and inclination for the control group was 6° retroversion and 8° superior inclination (both SD 4°). The mean CSA, PAS, coracoid-posterior acromion angle, posterior acromion-scapular plane angle, and fulcrum axis ratio were 30° (SD 4°), 64° (SD 8°), 116° (SD 9°), 55° (SD 7°), and 46% (SD 4%), respectively. Patients with osteoarthritis had a significant lower CSA, posterior acromion-scapular plane angle, coracoid-posterior acromion angle, and fulcrum axis ratio (27°, 50°, 111°, and 44%, all P < .001). We found a significant difference between the control group and the respective glenoid types for the following parameters: mean CSA and coracoid-posterior acromion angle for A glenoids (27°, P = .001, and 111°, P = .007); mean version, CSA, PAS, coracoid-posterior acromion angle, posterior acromion-scapular plane angle, and fulcrum axis ratio for B glenoids (11°, 27°, 71°, 111°, 49°, and 43%, all P < .001); and mean version, CSA, and posterior acromion-scapular plane angle for D glenoids (2°, P = .002, 26°, P = .003, and 48°, P = .007). DISCUSSION: There seems to be an association between prearthropathy scapular anatomy and shoulder osteoarthritis. A small lateral extension and less posterior rotation of the acromion is associated with shoulder osteoarthritis and is present in almost all types and subtypes of glenoid morphology. Furthermore, B and D glenoids are associated with, respectively, a more and less pronounced prearthropathy glenoid retroversion.

Does the Walch type B shoulder have a transverse force couple imbalance? A volumetric analysis of segmented rotator cuff muscles in osteoarthritic shoulders.

BACKGROUND: The etiology of the Walch type B shoulder remains unclear. We hypothesized that a scapulohumeral muscle imbalance, due to a disturbed transverse force couple (TFC) between the anterior and posterior rotator cuff muscles, may have a role in the pathogenesis of the type B morphology. The purpose of this study was to determine whether there is a TFC imbalance in the Walch type B shoulder using an imaging-based 3-dimensional (3D) volumetric and fatty infiltration assessment of segmented rotator cuff muscles. METHODS: Computed tomography images of 33 Walch type A and 60 Walch type B shoulders with the complete scapula and humerus including the distal humeral epicondyles were evaluated. The 3D volumes of the entire subscapularis, supraspinatus, and infraspinatus-teres minor (Infra-Tm) were manually segmented and analyzed. Additionally, anthropometric parameters including glenoid version, glenoid inclination, posterior humeral head subluxation, and humeral torsion were measured. The 3D muscle analysis was then compared with the anthropometric parameters using the Wilcoxon rank sum and Kruskal-Wallis tests. RESULTS: There were no significant differences (P > .200) in muscle volume ratios between the Infra-Tm and the subscapularis in Walch type A (0.93) and type B (0.96) shoulders. The fatty infiltration percentage ratio, however, was significantly greater in type B shoulders (0.94 vs. 0.75, P < .001). The Infra-Tm to subscapularis fatty infiltration percentage ratio was significantly larger in patients with >75% humeral head subluxation than in those with 60%-75% head subluxation (0.97 vs. 0.74, P < .001) and significantly larger in patients with >25° of retroversion than in those with <15° of retroversion (1.10 vs. 0.75, P = .004). The supraspinatus fatty infiltration percentage was significantly lower in Walch type B shoulders than type A shoulders (P = .004). Walch type A shoulders had mean humeral retrotorsion of 22° ± 10° whereas Walch type B shoulders had humeral retrotorsion of only 14° ± 9° relative to the epicondylar axis (P < .001). CONCLUSION: The TFC is in balance in the Walch type B shoulder in terms of 3D volumetric rotator cuff muscle analysis; however, the posterior rotator cuff does demonstrate increased fatty infiltration. Posterior humeral head subluxation and glenoid retroversion, which are pathognomonic of the Walch type B shoulder, may lead to a disturbance in the length-tension relationship of the posterior rotator cuff, causing fatty infiltration.

Aseptic osteonecrosis of the shoulder: Etiologies, diagnosis and medical management.

Aseptic osteonecrosis of the humeral head is a multifactorial entity in which the final common pathway results in disrupted blood supply, increased intraosseous pressure, and bone death. It follows a pathologic and radiographic pattern of progression similar to that seen at the hip. Much of the information regarding the disease has been extrapolated from findings in the femoral head. In addition, many treatment modalities have been adapted from techniques used in the hip. The causative underlying factors seem to be multifactorial and can be traumatic or non-traumatic. Although clinical symptoms and the underlying cause of the disease influence the treatment of each patient, staging is the most objective criterion in determining the most appropriate treatment. Earlier identification of osteonecrosis should facilitate the management. MRI is important for asymptomatic humeral head osteonecrosis in patients with poor clinical symptom and risk factor. Conservative treatment can be effective in stages I and II, When symptoms persist and there are signs of collapse despite conservative treatment, surgical intervention is advocated.

Real-time intraoperative 3D image intensifier-based navigation in reversed shoulder arthroplasty- analyses of image quality.

BACKGROUND: Due to the high anatomical variability and limited visualization of the scapula, optimal screw placement for baseplate anchorage in reversed total shoulder arthroplasty (rTSA) is challenging. Image quality plays a key role regarding the decision of an appropriate implant position. However, these data a currently missing for rTSA and were investigated in the present study. Furthermore, the rate of required K-wire changes for the central peg as well as post-implantation inclination and version were assessed. METHODS: In ten consecutive patients (8 female, 86 years, range 74-94) with proximal humeral fracture and indication for rTSA, an intraoperative 3D-scan of the shoulder with a 3D image intensifier (Ziehm Vision FD Vario 3D© [Ziehm Imaging GmbH, Nürnberg, Germany]) was performed after resection of the humeral head. Using the Vectorvision© Software (Brainlab AG, Feldkirchen, Germany), the virtual anatomy was compared to the visible anatomical landmarks. After implantation of the baseplate, a 3D scan was performed. All 3D scans included multiplanar reconstruction (MPR) and the cinemode to examine screw and baseplate placement. The rate of required K-wire changes was assessed. The intraoperative 3D image quality (modified visual analogue scale [VAS] and point system) was assessed before and after implantation of the glenoid component. Inclination and version were determined in post-implantation scans. RESULTS: The virtually presented anatomical landmarks always correlated to the anatomical visible points indicating an good virtual accuracy. The central K-wire position was corrected in three cases due to a deviation from the face plane technique position. The VAS was higher for the pre-implantation MPR (6.7, range 5-8) compared to the post-implantation acquired MPR (5.1, range 4-6; p = 0.0002). The point system showed a reduced quality in all subcategories, especially regarding the grading of the articular surfaces. The preoperative (7.9, range 6-9) and post-implantation (7.9, range 6-9) cinemode displayed no significant differences (p = 0.6). CONCLUSION: The present study underlines the need for the improvement of 3D image intensifiers algorithms to reduce artifact associated impaired image quality to enhance the benefit of real-time intraoperative 3D scans and navigation.

Humeral head resurfacing is associated with less pain and clinically equivalent functional outcomes compared with stemmed hemiarthroplasty at mid-term follow-up.

PURPOSE: Humeral head resurfacing (HHR) is a less invasive, anatomic alternative to the conventional stemmed hemiarthroplasty in patients in whom isolated humeral head replacement is preferred. It was hypothesized that, in a mid-term cross-sectional subjective outcome analysis, HHR would have equivalent patient-reported and functional outcomes to stemmed hemiarthroplasty (HA). METHODS: A total of 213 HHR and 153 HA procedures were performed at a single academic institution from 2000 to 2014. Of these, 106 HHR and 47 HA patients corresponding with 120 HHR and 55 HA shoulders responded to a survey that collected patient demographics, surgical outcomes, patient satisfaction, and self-reported range of motion scores using both bespoke and validated metrics. RESULTS: Follow-up was longer in the HA group (9.4 ± 3.4 vs. 5.2 ± 1.8 years, p < 0.0001). Self-reported range of motion was equivalent between groups. Surgery was perceived as helpful following 76.7% of HHRs and 78.2% of HAs (p > 0.99). The ASES pain subscore was significantly worse in the HA group (25.2 ± 29.5 vs. 38.5 ± 12.7 after HHR, p < 0.0001), which translated into worse ASES total scores (45.1 ± 14.8 HA vs. 52.2 ± 23.7 HHR, p < 0.05). These findings were equivocal in responses received 2-8 years vs. ≥ 8 years after surgery. CONCLUSIONS: Indications should be equivocal; humeral head resurfacing is a viable alternative to hemiarthroplasty, with equivalent patient satisfaction and reduced pain in the mid-term post-operative period. LEVEL OF EVIDENCE: III.

The Walch type B humerus: glenoid retroversion is associated with torsional differences in the humerus.

BACKGROUND: The Walch type B glenoid has the hallmark features of retroversion, joint subluxation, and bony erosion. Although the type B glenoid has been well described, the morphology of the corresponding type B humerus is poorly understood. As such, the aim of this imaging-based anthropometric study was to investigate humeral torsion in Walch type B shoulders. METHODS: Three-dimensional models of the full-length humerus were generated from computed tomography data for the Walch type B group (n = 59) and for a control group of normal nonarthritic shoulders (n = 59). An anatomic humeral head-neck plane was created and used to determine humeral torsion relative to the epicondylar axis. Measurements were repeated, and intraclass correlation coefficients were calculated. RESULTS: The type B humeri had significantly (P < .001) less retrotorsion (14° ± 9°) than the control group (36° ± 12°) relative to the epicondylar axis. Male and female individuals within the control group showed statistically significant differences in humeral torsion (P = .043), which were not found in the type B group. Inter-rater reliability showed excellent agreement for humeral torsion (intraclass correlation coefficient, 0.962). A subgroup analysis between Walch type B2 and B3 shoulders showed no significant differences in any of the humeral or glenoid parameters. CONCLUSION: The Walch type B humerus has significantly less retrotorsion than non-osteoarthritic shoulders. At present, it is unknown whether the altered humeral retrotorsion is a cause or effect of the type B glenoid. In addition, it is unknown whether surgeons should be reconstructing type B2 humeral component version to pathologic torsion or to nonpathologic population means to optimize arthroplasty survivorship.

Three-dimensional characterization of the anteverted glenoid (type D) in primary glenohumeral osteoarthritis.

BACKGROUND: The Walch classification describes glenoid morphology in primary arthritis. As knowledge grows, several modifications to the classification have been proposed. The type D, a recent modification, was defined as an anteverted glenoid with or without anterior subluxation. Literature on the anteverted glenoid in primary osteoarthritis is limited. The purpose of this study, therefore, was to analyze the anatomic characteristics of the type D glenoid on radiographs and computed tomography (CT). METHODS: The shoulder arthroplasty databases from 3 institutions were examined to identify patients with primary glenohumeral osteoarthritis and glenoid anteversion (≥5°), with or without anterior subluxation. The type D study cohort consisted of 18 patients (3% of the osteoarthritis cohort) and was a mean of 70 years old, with 11 women and 7 men. All radiographs were reviewed, and computed tomography Digital Imaging and Communications in Medicine (National Electrical Manufacturers Association, Rosslyn, VA, USA) data were analyzed on validated 3-dimensional imaging software. Rotator cuff fatty infiltration, glenoid measurements (anteversion and inclination), and humeral head subluxation according to the scapular plane were determined. RESULTS: In the study cohort, the mean glenoid anteversion was 12° (range, 5°-24°), the mean inclination was 0°, and the mean anterior subluxation was 38% (range, 6%-56%). Eight patients (44%) had a biconcave glenoid with a posterosuperiorly positioned paleoglenoid and an anteroinferiorly positioned neoglenoid, and 10 patients had a monoconcave glenoid. Fatty infiltration of the rotator cuff muscles never exceeded Goutallier stage 2. CONCLUSION: The type D glenoid is an addition to the original Walch classification and is characterized by glenoid anteversion (≥5°), anteroinferior humeral head subluxation, and absence of severe subscapularis fatty infiltration.

Functional workspace and patient-reported outcomes improve after reverse and total shoulder arthroplasty.

BACKGROUND: Low-cost motion analysis systems (LCMASs) have emerged as easy and practical methods to measure the functional workspace (FWS). Thus, we ventured to apply an LCMAS, the Kinect2 gaming camera, to evaluate the FWS in patients with shoulder osteoarthritis (OA) and patients who underwent total shoulder arthroplasty (TSA) or reverse total shoulder arthroplasty (RTSA). METHODS: A cross-sectional study of participants with OA (n = 53), TSA (n = 70), and RTSA (n = 34) was performed. The FWS as measured by an LCMAS, the American Shoulder and Elbow Surgeons (ASES) Standardized Shoulder Assessment Form score, and the Patient-Reported Outcomes Measurement Information System (PROMIS) score were collected. For participants who underwent TSA or RTSA, the FWS was evaluated at 6, 12, and 24 months postoperatively. The correlation of the FWS with the ASES score and PROMIS score was determined. Significance was set at P < .05. RESULTS: Patients who underwent TSA or RTSA had a significantly higher FWS than patients with shoulder OA at almost all time points. Patients who underwent TSA had a significantly higher FWS than patients who underwent RTSA at 24 months after surgery. PROMIS and ASES scores showed strong correlations with the FWS in patients who underwent TSA (R = 0.75 [P < .001] and R = 0.83 [P < .001], respectively) and RTSA (R = 0.84 [P < .001] and R = 0.73 [P < .001], respectively). CONCLUSION: The FWS measured by an LCMAS is an easy and low-cost method to quantify the reachable space of the hand in patients and shows strong correlations with patient-reported outcome measures. This may be a useful tool to assess upper-extremity range of motion before and after shoulder arthroplasty.