[Imaging of posttraumatic shoulder instability : Current concepts]. / Bildgebung bei posttraumatischen Instabilitäten der Schulter : Aktuelle Konzepte.

Posttraumatic instability accounts for more than 95% of all shoulder instabilities with the highest incidence in patients between 20 and 30 years of age. In this age group, lesions of the capsulolabral complex are the most common sequelae after the first shoulder dislocation. Typical acute findings are the Bankart and Perthes lesions and humeral avulsion of the glenohumeral ligament (HAGL). Chronic sequelae are anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesions, and nonclassifiable lesions with deficient anterioinferior labrum and glenohumeral ligaments. Recently, quantification of Hill-Sachs and bony Bankart lesions with glenoid defects have become the focus of interest: bipolar bone loss has emerged to be one important factor of recurrent instability that has not been addressed during the first stabilizing operation. The glenoid track concept emphasizes the importance of bipolar bone loss, where the glenoid track refers to the contact area between the humeral head and the glenoid at the end-range of motion in abduction, extension and external rotation. Any lesion of the humeral head that extends beyond the glenoid track is considered high risk for engagement of the humeral head at the glenoid margin with subsequent dislocation. Both the Hill-Sachs interval and the glenoid track can be determined using computed tomography (CT) and magnetic resonance imaging and, thus, help to define the status of the shoulder (on-track vs. off-track), which is prerequisite for planning the appropriate operative procedure. Similar tendencies also exist for posttraumatic posterior instabilities which are much rarer.

Humeral Head Reconstruction of Reverse Hill-Sachs Lesions.

Compared with anterior instability, posterior shoulder dislocations are a rare entity and are often missed at presentation. A concomitant anteromedial impression fracture of the humeral head, or a reverse Hill-Sachs lesion, is commonly present with these dislocations and is more pronounced with a longer timeline to reduction. Treatment of these defects ranges from nonsurgical treatment to soft-tissue procedures, bony reconstruction, and arthroplasty. Management may be dictated by various factors, such as patient demands, defect size and location, concomitant injuries, and underlying etiology. Small reverse Hill-Sachs defects without engagement can generally be treated nonsurgically or with benign neglect, whereas larger defects (>20%) often require surgery. The most reported surgical techniques are the (arthroscopic) McLaughlin and modified McLaughlin procedure, disimpaction and bone grafting, or reconstruction of the defect with autograft or with fresh (or fresh-frozen) osteochondral allograft. Finally, arthroplasty is generally required for large defects, where more than 45% to 50% of the articular cartilage is involved. Overall, reported outcomes generally reflect patient satisfaction for most patients, with a low incidence of secondary instability or posttraumatic arthritis, although better results are achieved when recognizing and treating these injuries in the more acute setting.

Surgical treatment of subchondral osteonecrosis of the humeral head: A case report and literature review.

BACKGROUND: Osteonecrosis of the humeral head is an uncommon subchondral bone disease with many etiologies, and there is currently no definite evidence to support an optimal surgical treatment plan. We report a case of surgical treatment of left humeral head necrosis. To the best of our knowledge, this is the youngest patient with non-drug-induced humeral head necrosis and the largest collapsed area. CASE PRESENTATION: The case involved a 16-year-old male who injured his left shoulder 1 year ago. The patient was admitted to the hospital because of shoulder pain after activity in the year following the injury. During the physical examination, the left glenohumeral joint space was tender, the pain was obvious when the shoulder joint was rotated and squeezed, and the active and passive range of motion was normal. X-ray, magnetic resonance imaging, and computed tomography + 3D computed tomography scans all showed subchondral osteonecrosis of the left humeral head. Left humeral head lesion removal and autologous osteochondral transplantation were performed, and the patient was followed up. CONCLUSION: Non-drug-induced humeral head necrosis is rare. Autologous osteochondral transplantation is currently one of the most mature and effective treatment methods. The short-term curative effect in this patient is satisfactory, but the patient is young and has a large collapsed area, so long-term follow-up is worthwhile.

Core decompression is superior to nonoperative management for humeral head osteonecrosis: a systematic review.

BACKGROUND: Much of the literature on osteonecrosis has traditionally focused on the hip, which remains the most common site for this disease. The shoulder and the knee are the second most frequently affected sites (both approximately 10% of the incidence). There are a variety of techniques for managing this disease, and it is important to optimize this for our patients. This review aimed to compare the results of core decompression (CD) vs. nonoperative modalities for the treatment of osteonecrosis of the humeral head, including (1) success rate defined as lack of progression to further procedures (shoulder arthroplasty) and no need for further intervention; (2) clinical results (patient-reported pain and functional scores); and (3) radiological outcomes. METHODS: We queried PubMed and found 15 reports that fit the inclusion criteria for studies concerning the use of CD as well as studies discussing nonoperative treatment for stage I-III osteonecrotic lesions of the shoulder. A total of 9 studies encompassed 291 shoulders that underwent CD analyzed at a mean follow-up of 8.1 years (range, 67 months-12 years), and 6 studies examined 359 shoulders that underwent nonoperative management at a mean follow-up of 8.1 years (range, 35 months-10 years). Outcomes of CD and nonoperative management included success rate, number of shoulders requiring shoulder arthroplasty, and evaluation of several normalized patient-reported outcomes. We also assessed radiographic progression (pre- to postcollapse or further collapse progression). RESULTS: The mean success rate of CD for avoiding further procedures was 76.6% (226 of 291 shoulders) in stage I through stage III. Stage III shoulders avoided shoulder arthroplasty in 63% (27 of 43 shoulders). Nonoperative management resulted in a success rate of 13%, P < .001. In the CD studies, 7 of 9 showed improvements in clinical outcome measurements compared with 1 of 6 of the nonoperative studies. Radiographically, there was less progression in the CD group (39 of 191 shoulders [24.2%]) vs. the nonoperative group (39 of 74 shoulders [52.3%]) (P < .001). CONCLUSIONS: Given the high success rate and positive clinical outcomes reported, CD is an effective method for management, especially when compared with nonoperative treatment methods for stage I-III osteonecrosis of the humeral head. The authors believe that it should be used as treatment to avoid arthroplasty in patients who have osteonecrosis of the humeral head.

Predictors of Bone Loss in Anterior Glenohumeral Instability.

BACKGROUND: Anterior shoulder instability can result in bone loss of both the anterior glenoid and the posterior humerus. Bone loss has been shown to lead to increased failure postoperatively and may necessitate more complex surgical procedures, resulting in worse clinical outcomes and posttraumatic arthritis. HYPOTHESIS/PURPOSE: The purpose of this study was to investigate predictors of glenoid and humeral head bone loss in patients undergoing surgery for anterior shoulder instability. It was hypothesized that male sex, contact sport participation, traumatic dislocation, and higher number of instability events would be associated with greater bone loss. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 892 patients with anterior shoulder instability were prospectively enrolled in the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort. The presence and amount of anterior glenoid bone loss and accompanying Hill-Sachs lesions were quantified. Descriptive information and injury history were used to construct proportional odds models for the presence of any bone defect, for defects >10% of the anterior glenoid or humeral head, and for combined bony defects. RESULTS: Anterior glenoid bone loss and Hill-Sachs lesions were present in 185 (20.7%) and 470 (52.7%) patients, respectively. Having an increased number of dislocations was associated with bone loss in all models. Increasing age, male sex, and non-White race were associated with anterior glenoid bone defects and Hill-Sachs lesions. Contact sport participation was associated with anterior glenoid bone loss, and Shoulder Actitvity Scale with glenoid bone loss >10%. A positive apprehension test was associated with Hill-Sachs lesions. Combined lesions were present in 19.4% of patients, and for every additional shoulder dislocation, the odds of having a combined lesion was 95% higher. CONCLUSION: An increasing number of preoperative shoulder dislocations is the factor most strongly associated with glenoid bone loss, Hill-Sachs lesions, and combined lesions. Early surgical stabilization before recurrence of instability may be the most effective method for preventing progression to clinically significant bone loss. Patients should be made aware of the expected course of shoulder instability, especially in athletes at high risk for recurrence and osseous defects, which may complicate care and worsen outcomes. REGISTRATION: NCT02075775 (ClinicalTrials.gov identifier).

Prognostic potential and pathological validation of a diagnostic application using Raman spectroscopy in the characterization of degenerative changes in the cartilage of the humeral head.

Significance: Raman spectroscopy is a well-established analytical method in the fields of chemistry, industry, biology, pharmaceutics, and medicine. Previous studies have investigated optical imaging and Raman spectroscopy for osteoarthritis (OA) diagnosis in weight-bearing joints such as hip and knee joints. However, to realize early diagnosis or a curable treatment, it is still challenging to understand the correlations with intrinsic factors or patients' background. Aim: To elucidate the correlation between the Raman spectral features and pathological variations of human shoulder joint cartilage. Approach: Osteoarthritic cartilage specimens excised from the humeral heads of 14 patients who underwent shoulder arthroplasty were assessed by a confocal Raman microscope and histological staining. The Raman spectroscopic dataset of degenerative cartilage was further analyzed by principal component analysis and hierarchical cluster analysis. Results: Multivariate association of the Raman spectral data generated three major clusters. The first cluster of patients shows a relatively high Raman intensity of collagen. The second cluster displays relatively low Raman intensities of proteoglycans (PGs) and glycosaminoglycans (GAGs), whereas the third cluster shows relatively high Raman intensities of PGs and GAGs. The reduced PGs and GAGs are typical changes in OA cartilage, which have been confirmed by safranin­O staining. In contrast, the increased Raman intensities of collagen, PGs, and GAGs may reflect the instability of the cartilage matrix structure in OA patients. Conclusions: The results obtained confirm the correlation between the Raman spectral features and pathological variations of human shoulder joint cartilage. Unsupervised machine learning methods successfully yielded a clinically meaningful classification between the shoulder OA patients. This approach not only has potential to confirm severity of cartilage defects but also to determine the origin of an individual's OA by evaluating the cartilage quality.

Editorial Commentary: Free Bone Block With Remplissage Provides Less Translation Than Free Bone Block Alone in Shoulder Instability Patients With Bipolar Bone Loss.

It would stand to reason that, in shoulder instability patients with bipolar bone loss, the combination of a bone block procedure and a remplissage procedure would provide better results than each one alone. Why would this be the case? When performing these procedures in the lateral decubitus position for patients with critical bipolar bone loss, the humeral head is anteriorly and inferiorly subluxed. This is most likely due to the incompetent restraints when in traction. A bone block procedure alone doesn't necessarily reduce the glenohumeral center of rotation; rather, it increases the "jump distance," making it more difficult for the humerus to dislocate over the bone block. However, the remplissage procedure not only makes the Hill-Sachs lesion extra-articular and prevents the defect from levering out the humerus, but also seems to pull the humeral head posteriorly centering it in the glenoid. This provides a posterior tether to the humeral head while increasing the jump distance over the bone block even further. In the future, one can anticipate a significant increase in remplissage-augmented bone block procedures in patients with bipolar bone loss.

Evaluating Bone Loss in Anterior Shoulder Instability.

Anterior shoulder instability is a common orthopaedic condition that often involves damage to the bony architecture of the glenohumeral joint in addition to the capsulolabral complex. Patients with recurrent shoulder dislocations are at increased risk for glenohumeral bone loss, as each instability event leads to the accumulation of additional glenoid and/or humeral head bone defects. Depending on the degree of bone loss, successful treatment may need to address bony lesions in addition to injured soft-tissue structures. As such, a thorough understanding of methods for evaluating bone loss preoperatively, in terms of location, size, and significance, is essential. Although numerous imaging modalities can be used, three-dimensional imaging has proven particularly useful and is now an integral component of preoperative planning.

Glenoid Bone Loss Directly Affects Hill-Sachs Morphology: An Advanced 3-Dimensional Analysis.

BACKGROUND: While the glenoid track concept presents a useful prediction for recurrent glenohumeral instability, little is known about the humeral head bony architecture as it relates to glenoid erosion in the setting of bipolar bone loss. PURPOSE: To (1) qualitatively and quantitatively analyze the interplay between glenoid bone loss (GBL) and Hill-Sachs lesions (HSLs) in a cohort of patients with anterior instability using 3-dimensional imaging software and (2) assess the relationships between GBL and HSL characteristics. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Patients were identified who had anterior shoulder instability with a minimum 5% GBL and evidence of HSL confirmed on computed tomography. Unilateral 3-dimensional models of the ipsilateral proximal humeral head and en face sagittal oblique view of the glenoid were reconstructed using MIMICS software (Materialise NV). GBL surface area, width, defect length, and glenoid track width were quantified. The volume, surface area, width, and depth of identified HSLs were quantified with their location (medial, superior, and inferior extent) on the humeral head. Severity of GBL was defined as percentage glenoid bone surface area loss and categorized as low grade (5%-10%), moderate grade (>10% to 20%), high grade (>20% to 30%), and extensive (>30%). Analysis of variance was then computed to determine significance (P < .05) between severity of GBL and associated HSL parameters. RESULTS: In total, 100 patients met inclusion criteria (mean age, 27.9 years; range, 18-43 years), which included 58 right shoulders and 42 left shoulders (84 male, 16 female). Among groups, there were 32 patients with low-grade GBL (mean GBL = 6.1%), 38 with moderate grade (mean GBL = 16.2%), 17 with high grade (mean GBL = 23.7%), and 13 with extensive (mean GBL = 34.0%), with an overall mean GBL of 18.1% (range, 5%-39%). Patients with 5%-10% GBL had significantly narrower HSLs (average and maximum width; P < .03) and deeper HSLs (average depth; P = .002) as compared with all other GBL groups, while greater GBL was associated with wider and shallower HSLs. GBL width, percentage width loss, defect length, and glenoid track width all significantly differed across the 4 GBL groups (P < .05). CONCLUSION: HSLs had significantly different morphological characteristics depending on the severity of GBL, indicating that GBL was directly related to the characteristics of HSLs. Patients presenting with smaller glenoid defects had significantly narrower and deeper HSLs with less humeral head surface area loss, while greater GBL was associated with wider and shallower HSLs.

Humeral head coverage in arthroscopic partial repair of massive rotator cuff tears improves functional outcomes: an analysis of influential factors.

BACKGROUND: Although partial rotator cuff repair has shown good outcomes, differences in clinical outcomes remain concerns. This study was performed to determine whether patients with humeral head coverage would show better functional outcomes than patients without humeral head coverage and to identify the factors for humeral head coverage after arthroscopic partial repair of massive tears. METHODS: We performed a retrospective study of 63 patients with massive rotator cuff tears who underwent arthroscopic partial repair between 2012 and 2018. Two to four margin convergences were first performed; then, the Mason-Allen technique was performed. The patients were divided into 2 groups: those with humeral head coverage (38 cases) and those without humeral head coverage (25 cases). The following factors were evaluated: age; sex; hypertension; diabetes; osteoporosis; preoperative and postoperative pseudoparalysis, visual analog scale (VAS) pain score, Constant score, acromiohumeral distance, and subacromial bony spur; and subscapularis tear and repair. Muscle atrophy and fatty degeneration were evaluated by magnetic resonance imaging preoperatively, and the integrity of the repaired cuff was evaluated by ultrasonography at a minimum of 2 years after surgery. RESULTS: Compared with preoperative values, significant improvements in VAS pain scores (from 6.27 to 2.32 in patients with humeral head coverage and from 7.00 to 2.81 in those without humeral head coverage) and Constant scores (from 51.35 to 75.95 and from 44.62 to 69.81, respectively) were observed in both groups (P < .001). Statistical analysis revealed that postoperative VAS pain scores (2.32 vs. 2.81) and Constant scores (75.95 vs. 69.81) in patients with humeral head coverage were superior to those in patients without humeral head coverage (P = .044 and P = .003, respectively). The integrity of the repaired cuff was evaluated by ultrasonography, and partial tears were found in 4 of 37 patients with humeral head coverage and 2 of 26 patients without humeral head coverage (P = .816). Univariable logistic regression analysis revealed that age (P < .001), comorbidity (P = .005), symptom duration (P = .023), preoperative shoulder mobility (P < .001), maintained acromiohumeral distance (P = .006), subscapularis tear (P = .026), and less preoperative supraspinatus and infraspinatus muscle atrophy (P = .001 and P = .010, respectively) had significant correlations with humeral head coverage. CONCLUSIONS: Overall satisfactory results were achieved in most patients regardless of high retear rates, but patients with partial repair covering the humeral head were associated with better outcomes than patients without humeral head coverage. Multivariable regression analysis revealed that age (<70 years, P = .003), capability of shoulder mobility (P = .005), maintenance of the acromiohumeral space (>7 mm, P = .016), and less atrophy of the rotator cuff muscles (P = .021) were favorable factors to achieve humeral head coverage during surgical partial repair of massive rotator cuff tears.

The association between anterior shoulder joint capsule thickening and glenoid deformity in primary glenohumeral osteoarthritis.

BACKGROUND: Anterior shoulder joint capsule thickening is typically present in osteoarthritic shoulders, but its association with specific patterns of glenoid wear is incompletely understood. We sought to determine the relationship between anterior capsular thickening and glenoid deformity in primary glenohumeral osteoarthritis. METHODS: We retrospectively identified 134 consecutive osteoarthritic shoulders with magnetic resonance imaging and computed tomography scans performed. Axial fat-suppressed magnetic resonance imaging slices were used to quantify the anterior capsular thickness in millimeters, measured at its thickest point below the subscapularis muscle. Computed tomography scans were used to classify glenoid deformity according to the Walch classification, and an automated 3-dimensional software program provided values for glenoid retroversion and humeral head subluxation. Multinomial and linear regression models were used to characterize the association of anterior capsular thickening with Walch glenoid type, glenoid retroversion, and posterior humeral head subluxation while controlling for patient age and sex. RESULTS: The anterior capsule was thickest in glenoid types B2 (5.5 mm, 95% confidence interval [CI]: 5.0-6.0) and B3 (6.1 mm, 95% CI: 5.6-6.6) and thinnest in A1 (3.7 mm, 95% CI: 3.3-4.2; P < .001). Adjusted for age and sex, glenoid types B2 (odds ratio: 4.4, 95% CI: 2.3-8.4, P < .001) and B3 (odds ratio: 5.4, 95% CI: 2.8-10.4, P < .001) showed the strongest association with increased anterior capsule thickness, compared to glenoid type A1. Increased capsular thickness correlated with greater glenoid retroversion (r = 0.57; P < .001) and posterior humeral head subluxation (r = 0.50; P < .001). In multivariable analysis, for every 1-mm increase in anterior capsular thickening, there was an adjusted mean increase of 3.2° (95% CI: 2.4-4.1) in glenoid retroversion and a 3.8% (95% CI: 2.7-5.0) increase in posterior humeral head subluxation. CONCLUSIONS: Increased thickening of the anterior shoulder capsule is associated with greater posterior glenoid wear and humeral head subluxation. Additional research should determine whether anterior capsular disease plays a causative role in the etiology or progression of eccentric glenohumeral osteoarthritis.

Full-field experimental analysis of the influence of microstructural parameters on the mechanical properties of humeral head trabecular bone.

Understanding the mechanical properties of trabecular bone within the metaphysis of the proximal humerus is becoming increasingly important for the design of humeral head joint replacement components that prioritize bone preservation. The aim of this study was to perform full-field mechanical testing methods on isolated trabecular bone cores from the humeral head to experimentally measure the local magnitude of strain before macroscopic failure and to characterize the ultimate strength of each core. Isolated cubic trabecular bone cores were extracted from the center of humeral head osteotomies retrieved from (1) patients with end-stage osteoarthritis (OA) undergoing total shoulder arthroplasty (TSA) and (2) normal nonpathologic cadaveric humeral heads. A custom computed tomography (CT)-compatible loading device was used to perform compressive mechanical testing. For 10 of the OA specimens, stepwise loading was performed directly within a microCT scanner and digital volume correlation (DVC) was used to measure full-field strains throughout the trabecular structure. A higher variability in ultimate strength was measured for the trabecular cores retrieved from OA humeral heads (range: 2.8-7.6 MPa) compared to the normal cadaveric humeral heads (range: 2.2-5.4 MPa), but no statistically significant difference between the groups was found (p = 0.06). Ultimate strength was strongly correlated with bone volume fraction (OA r2 = 0.72; normal r2 = 0.76) and bone mineral content (OA r2 = 0.79; normal r2 = 0.77). At the trabecular level, 95th percentile of third principal strains, measured at a subvolume size of 152 µm, exceeded 19,000 µÎµ for each of the 10 specimens (range: -19,551 to -36,535 µÎµ) before macroscopic failure of the cores occured. No strong linear correlations (r2 ≥ 0.50) were found between the median or 95th percentile of DVC third principal strain and the corresponding morphometric parameters of each individual bone core. The results of this study indicate that bone volume fraction and bone mineral content heavily influence the apparent ultimate strength of trabecular bone cores collected from OA patients undergoing TSA. Clinical significance: The strong correlations observed within this study further emphasize the importance of considering bone mineral content or bone volume fraction measurements in assessing the localized risk of trabecular bone fracture for orthopedic applications.

Factors related to large bone defects of bipolar lesions and a high number of instability episodes with anterior glenohumeral instability.

BACKGROUND: Significant bone defects are associated with poor clinical results after surgical stabilization in cases of glenohumeral instability. Although multiple factors are thought to adversely affect enlargement of bipolar bone loss and increased shoulder instability, these factors have not been sufficiently evaluated. The purpose of this study was to identify the factors related to greater bone defects and a higher number of instability episodes in patients with glenohumeral instability. METHODS: A total of 120 consecutive patients with symptomatic unilateral instability of the glenohumeral joint were retrospectively reviewed. Three-dimensional surface-rendered/registered models of bilateral glenoids and proximal humeri from computed tomography data were matched by software, and the volumes of bone defects identified in the glenoid and humeral head were assessed. After relationships between objective variables and explanatory variables were evaluated using bivariate analyses, factors related to large bone defects in the glenoid and humeral head and a high number of total instability episodes and self-irreducible dislocations greater than the respective 75th percentiles were evaluated using logistic regression analyses with significant variables on bivariate analyses. RESULTS: Larger humeral head defects (P < .001) and a higher number of total instability episodes (P = .032) were found to be factors related to large glenoid defects. On the other hand, male sex (P = .014), larger glenoid defects (P = .015), and larger number of self-irreducible dislocations (P = .027) were related to large humeral head bone defects. An increased number of total instability episodes was related to longer symptom duration (P = .001) and larger glenoid defects (P = .002), and an increased number of self-irreducible dislocations was related to larger humeral head defects (P = .007). CONCLUSIONS: Whereas this study showed that bipolar lesions affect the amount of bone defects reciprocally, factors related to greater bone defects differed between the glenoid and the humeral head. Glenoid defects were related to the number of total instability episodes, whereas humeral head defects were related to the number of self-irreducible dislocations.

Shoulder Position During Magnetic Resonance Arthrogram Significantly Affects Capsular Measurements.

PURPOSE: To determine whether change in shoulder position between internal rotation (IR) and external rotation (ER) during magnetic resonance arthrography (MRA) affects previously defined capsular measurements and to determine the utility of rotation in the diagnosis of instability. METHODS: A retrospective study was conducted of patients who received a shoulder MRA with humeral IR and ER views. Patients with an arthroscopically confirmed diagnosis of instability and those with clinically stable shoulders, no history of instability, and no MRA findings of instability were identified and compared. Humeral rotation, glenoid retroversion, humeral head subluxation, capsular length, and capsular area using axial sequences of IR and ER views were recorded. Analysis compared IR, ER, and Δ capsular measurements between groups using independent t tests and univariate and multivariate regression. RESULTS: Thirty-one subjects who were diagnosed with instability were included, along with 28 control subjects. Capsular length, capsular area, and humeral subluxations were significantly greater with ER compared with IR views (P < .001, P < .001, P < .001). Patients with instability displayed greater ER capsular length (P = .0006) and ER capsular area (P = .005) relative to controls. Multivariate logistic regression identified age, weight, sex, ER capsular length, and retroversion to be significant predictors of instability. ER capsular length independently predicts instability with 86% sensitivity and 84% specificity. Interobserver reliability using the intraclass correlation coefficient was rated good or excellent on all measurements. CONCLUSION: Variance in humeral rotation during shoulder MRA significantly affects capsular measurements. Rotational views increase the utility of capsular measurements when assessing for instability, particularly capsular length and capsular area. The implementation of ER positioning enhances the ability to examine capsular changes of the shoulder joint and can assist in the diagnosis of instability. LEVEL OF EVIDENCE: III, retrospective comparative study.

Reproducibility of the modified Neer classification defining displacement with respect to the humeral head fragment for proximal humeral fractures.

BACKGROUND: Although the Neer classification is widely used for the assessment of proximal humeral fractures, its reproducibility has been challenged. The purpose of this study was to evaluate the reproducibility of the conventional Neer classification and a modified classification that defined fracture displacement with respect to the humeral head fragment. METHODS: The fracture patterns in 80 cases of proximal humeral fractures were independently assessed by 6 observers. The cases were grouped according to the conventional Neer classification using radiographs followed by computed tomography (CT) scans by each examiner twice with a 1-month interval. The fractures were then classified with the modified Neer classification, which defined displacement of the fragment as separation of more than 1 cm or angulation of more than 45° from the humeral head fragment, twice with a 1-month interval. Kappa coefficients of the conventional and modified Neer classifications were compared. RESULTS: The modified classification showed significantly higher intra-observer agreement than the conventional classification, both for radiographs (P = .028) and for CT scans (P = .043). Intra-observer agreement was also significantly higher for the modified classification than for the conventional classification, both for radiographs (P = .001) and for CT scans (P < .001). CONCLUSIONS: The present study showed that agreement for the Neer classification could be improved when fracture displacement was defined as separation or angulation from the humeral head. Considering vascularity to the humeral head, furthermore, the modified method might be more helpful for predicting patients' prognosis than the conventional Neer classification.

Neuropathic Glenohumeral Joint Resorption.

An 81-year-old woman was evaluated by a physical therapist at a skilled nursing facility 3 days post total knee arthroplasty (TKA). Following the evaluation, the on-call physician was consulted and radiographs were ordered. Radiographs revealed a chronic neuropathic joint with complete resorption of the humeral head and heterotopic ossification at the scapula. J Orthop Sports Phys Ther 2020;50(8):466. doi:10.2519/jospt.2020.9174.

When to Abandon the Arthroscopic Bankart Repair: A Systematic Review.

CONTEXT: Bone loss is a major factor in determining surgical choice in patients with anterior glenohumeral instability. Although bone loss has been described, there is no consensus on glenoid, humeral head, and bipolar bone loss limits for which arthroscopic-only management with Bankart repair can be performed. OBJECTIVE: To provide guidelines for selecting a more complex repair or reconstruction (in lieu of arthroscopic-only Bankart repair) in the setting of glenohumeral instability based on available literature. DATA SOURCES: An electronic search of the literature for the period from 2000 to 2019 was performed using PubMed (MEDLINE). STUDY SELECTION: Studies were included if they quantified bone loss (humeral head or glenoid) in the setting of anterior instability treated with arthroscopic Bankart repair. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 4. DATA EXTRACTION: Study design, level of evidence, patient demographics, follow-up, recurrence rates, and measures of bone loss (glenoid, humeral head, bipolar). RESULTS: A total of 14 studies met the inclusion criteria. Of these, 10 measured glenoid bone loss, 5 measured humeral head bone loss, and 2 measured "tracking" without explicit measurement of humeral head bone loss. Measurement techniques for glenoid and humeral head bone loss varied widely. Recommendations for maximum glenoid bone loss for arthroscopic repair were largely <15% of glenoid width in recent studies. Recommendations regarding humeral head loss were more variable (many authors providing only qualitative descriptions) with increasing attention on glenohumeral tracking. CONCLUSION: It is essential that a standardized method of glenoid and humeral head bone loss measurements be performed preoperatively to assess which patients will have successful stabilization after arthroscopic Bankart repair. Glenoid bone loss should be <15%, and humeral head lesions should be "on track" if an arthroscopic-only Bankart is planned. If there is greater bone loss, adjunct or open procedures should be performed.

Idiopathic humeral head osteonecrosis mimicking rotator cuff disorders: Two challenging diagnostic case reports.

RATIONALE: Shoulder pain is a common complaint among patients, and rotator cuff disorders are the most common diagnoses. Humeral head osteonecrosis is easily masked by other more common diagnoses and concomitant conditions. PATIENT CONCERNS: This challenging diagnostic report consists of 2 cases. Case 1 was that of a 59-year-old man who presented with right shoulder pain that had lasted for >1 year. Case 2 was that of a 52-year-old man who complained of right shoulder pain lasting for 6 months. They both presented with chronic right shoulder pain without relevant trauma history, and the physical examination showed a tenderness point over the right greater tuberosity. DIAGNOSIS: These 2 patients were diagnosed with osteonecrosis involving the right greater tuberosity region via magnetic resonance imaging. INTERVENTIONS: In case 1, the patient underwent cord decompression and artificial bone grafting with C-arm guidance. In case 2, the patient refused surgical intervention and decided to continue receiving physical therapy for symptom control. OUTCOMES: In case 1, the patient responded well to cord decompression and artificial bone grafting. After the surgery, the active range of motion was restored and the pain in the right shoulder diminished further. In case 2, conservative treatment helped alleviate the patient's shoulder pain but did not entirely eliminate it. LESSONS: Physicians should always have a high index of suspicion for osteonecrosis, especially when treating chronic shoulder pain, regardless of whether there are typical symptoms/known risk factors or not.

Morphological and Apparent-Level Stiffness Variations Between Normal and Osteoarthritic Bone in the Humeral Head.

Osteoarthritis (OA) is characterized by morphological changes that alter bone structure and mechanical properties. This study compared bone morphometric parameters and apparent modulus between humeral heads excised from end-stage OA patients undergoing total shoulder arthroplasty (n = 28) and non-pathologic normal cadavers (n = 28). Morphometric parameters were determined in central cores, with regional variations compared in four medial to lateral regions. Linear regression compared apparent modulus, morphometric parameters, and age. Micro finite element models estimated trabecular apparent modulus and derived density-modulus relationships. Significant differences were found for bone volume fraction (p < 0.001) and trabecular thickness (p < 0.001) in the most medial regions. No significant differences occurred between morphometric parameters and apparent modulus or age, except in slope between groups for apparent modulus versus trabecular number (p = 0.021), and in intercept for trabecular thickness versus age (p = 0.040). Significant differences occurred in both slope and intercept between density-modulus regression fits for each group (p ≤ 0.001). The normal group showed high correlations in the power-fit (r2 = 0.87), with a lower correlation (r2 = 0.61) and a more linear relationship, in the OA group. This study suggests that alterations in structure and apparent modulus persist mainly in subchondral regions of end-stage OA bone. As such, if pathologic regions are removed during joint replacement, computational models that utilize modeling parameters from non-pathologic normal bone may be applied to end-stage OA bone. An improved understanding of humeral trabecular bone variations has potential to improve the surgical management of end-stage OA patients. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:503-509, 2020.