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.

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.

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.

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.

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.

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.

Risk factors for anterior shoulder instability: a matched case-control study.

BACKGROUND: Anatomic skeletal features of the shoulder play important roles in anterior shoulder dislocation. However, studies on the effect of the humeral structure are few. This case-control study aimed to analyze the risk factors of anterior shoulder instability, including glenoid and humeral factors. METHODS: Anterior shoulder instability was found in 64 of 10,035 individuals who underwent magnetic resonance imaging. Propensity score matching was used to select controls matched for age, sex, height, and weight. We analyzed the glenoid and humeral structural data using conditional logistic regression analysis and identified cutoff points using receiver operating characteristic curve analysis. RESULTS: Significant differences were found between the control and dislocation groups in the depth-to-width ratio (0.119 ± 0.034 vs. 0.105 ± 0.037, P = .021), height-to-width ratio (1.51 ± 0.13 vs. 1.67 ± 0.16, P < .001), humeral head diameter-to-glenoid fossa diameter ratio (1.56 ± 0.11 vs. 1.64 ± 0.20, P < .001), and humeral containing angle (67.3° ± 5.9° vs. 60.4° ± 5.9°, P < .001). The humeral containing angle (odds ratio, 0.95; P = .024) and the glenoid height-to-width ratio (odds ratio, 7.88; P = .002), adjusted for the depth-to-width ratio and diameter ratio, were associated with anterior shoulder instability. The cutoff point for the humeral containing angle was 64° and for the height-to-width ratio was 1.60. CONCLUSIONS: This study revealed significant risk factors for shoulder instability in the Chinese Han population. The humeral containing angle and the glenoid height-to-width ratio were risk factors for anterior shoulder instability.

Bone healing potential of fascia lata autografts to the humeral head footprint in rotator cuff reconstruction based on magnetic resonance imaging and histologic evaluations.

BACKGROUND: The purpose of the study was to evaluate the bone healing potential of fascia lata autograft (FLA) by magnetic resonance imaging (MRI) and histologic analysis. METHODS: The study included 69 patients assessed by MRI after an FLA patch procedure. Three of the 69 patients underwent a revision procedure after the primary FLA procedure; 1 underwent a second-look arthroscopy and 2 underwent reverse shoulder arthroplasties (RSAs). In the 2 RSA patients, we histologically evaluated greater tuberosities with the repaired graft. Moreover, as a control, we harvested the greater tuberosity with the cuff tendon at the time of RSA for failed open reduction-internal fixation of 4-part proximal humeral fracture. Based on MRI, retear cases were divided into type 1 (the graft did not remain on the greater tuberosity) and type 2 (the graft remained on the greater tuberosity). Histologic sections were evaluated to examine fascia-bone or rotator cuff-bone interfaces. RESULTS: There were 35 intact repairs: 7 type 1 and 27 type 2 shoulders (type 1 vs. type 2, P < .001). Second-look arthroscopic findings confirmed that the graft was securely attached to the greater tuberosity. Histologic analysis of greater tuberosities in RSA patients showed solid continuity of the graft to the bone, with cells with nuclei in the collagen matrix oriented in parallel. The FLA to bone junction consisted of the FLA, fibrocartilage, and bone, which is similar to the normal cuff tendon to bone junction. CONCLUSIONS: These results indicate that a fresh cellular FLA has good to excellent bone healing potential.

Anatomic locking plates for complex proximal humeral fractures: anatomic neck fractures versus surgical neck fractures.

BACKGROUND: Continued debate exists on the management of displaced 3- or 4-part proximal humeral fractures. Only a few studies have compared the efficacy of proximal humeral locking plates (PHLPs) for treating anatomic neck fractures (ANFs) and surgical neck fractures (SNFs). METHODS: The medical data of 31 consecutive patients with displaced 4-part proximal humeral fractures treated with PHLPs between May 2013 and April 2015 were reviewed retrospectively. We divided the patients into the ANF and SNF groups and assessed the neck-shaft angle (NSA), sum of the screw tip-articular surface distance, and other parameters postoperatively at 3 days and at 12 months using shoulder radiographs. The Constant-Murley scores were assessed at 3 days, 12 months, and last follow-up. RESULTS: The ANF group had a significantly lower mean age and significantly greater mean operative duration, estimated blood loss, and rate of bone grafting. Full or partial osteonecrosis of the humeral head developed in 7 patients and 1 patient in the ANF and SNF groups, respectively. Screw cutout and/or pullout complications occurred in 8 cases in the ANF group but not in the SNF group. In the ANF group, the values for NSA and the sum of the screw tip-articular surface distance changed significantly from 3 days to 12 months postoperatively. There were no significant correlations among the tested parameters. CONCLUSION: ANFs resulted in more complications at a younger age than SNFs. ANF treatment using PHLPs is more prone to a decreased NSA and humeral head osteonecrosis and has poorer clinical outcomes than SNF treatment using PHLPs.

Cuff tear arthropathy in the nineteenth century: 'chronic rheumatic arthritis' with 'partial luxation upwards' of the humeral head.

INTRODUCTION: Cuff tear arthropathy of the shoulder is a common indication for insertion of an increasing number of reverse shoulder arthroplasties. It is widely believed that this condition was unknown to medical practitioners and writers prior to the introduction of the term cuff tear arthropathy by Charles Neer in 1977. PURPOSE: To search nineteenth-century written sources for pathoanatomical and biomechanical descriptions of the typical changes found in cuff tear arthropathy. METHODS: A historical review. Nineteenth-century medical textbooks, reviews, case series, autopsy reports and illustrations were systematically searched and retrieved for relevance. References were hand-searched. Illustrations were reproduced and interpreted. RESULTS: A richly illustrated nineteenth-century literature was identified. The typical changes in cuff tear arthropathy were termed 'chronic rheumatic arthritis' of the shoulder with 'partial luxation upwards' of the humeral head and interpreted within a pathoanatomical and biomechanical framework. Detailed descriptions and illustrations of massive rotator cuff tears, biceps pathology and the osseous changes were identified and presented. CONCLUSION: The pathoanatomical and biomechanical changes later termed cuff tear arthropathy were well understood and nicely described in nineteenth-century medical literature.

Synthetic osteochondral resurfacing for treatment of large caudocentral osteochondritis dissecans lesions of the humeral head in 24 dogs.

OBJECTIVE: To report the outcome of dogs with large, caudocentral, osteochondritis dissecans (OCD) lesions of the humeral head treated with synthetic osteochondral resurfacing (SOR) implants. STUDY DESIGN: Retrospective case series. ANIMALS: Twenty-four client-owned large breed or giant dogs. METHODS: The medical records of all dogs treated with first generation (G1) and second generation (G2) SOR implants were reviewed. All dogs were assessed with clinical examination and imaging 12 weeks after surgery. Assessment of outcome was based on subjective assessment of lameness, scoring of postoperative radiographs, and the Liverpool Osteoarthritis in Dogs (LOAD) questionnaire. RESULTS: Osteochondral resurfacing was performed with a G1 implant in 13 dogs (15 shoulders) and a G2 implant in 11 dogs (13 shoulders). Lameness resolved in all dogs treated with G1 implants and in 10 dogs treated with G2 implants by 12 weeks after surgery. One dog treated with a G2 implant was found to have an implant-associated infection, requiring implant removal. No recurrence of lameness was reported in 9 limbs treated with G1 implants and 10 limbs treated with G2 implants that were available for clinical review at a median time of 387 and 365 days, respectively, after surgery. Mean postoperative LOAD scores were 4.2 of 52 and 5.2 of 52 in dogs treated with a G1 or a G2 implant, respectively. CONCLUSION: Synthetic resurfacing was technically feasible in all joints of this study and resulted in good clinical results. CLINICAL SIGNIFICANCE: The use of SOR implants seems viable to treat large caudocentral OCD lesions of the humeral head in dogs and warrants prospective comparison with conventional arthroscopic treatment.

Rapid Progressive Osteonecrosis of the Humeral Head After Arthroscopic Rotator Cuff Surgery.

PURPOSE: To verify the clinical features and the risk factors of rapid progressive osteonecrosis of the humeral head after arthroscopic rotator cuff surgery (ARCS). METHODS: Data and medical records of 24 patients who had rapid progressive collapse of the humeral head after ARCS performed from October 2012 to March 2016 were retrospectively analyzed. Among them, 8 patients demonstrated no evidence of osteonecrosis of the humeral head preoperatively yet developed rapid progressive collapse of the humeral head within 12 months after ARCS. RESULTS: All patients were women with a mean age of 64.0 years (range, 52-74 years), and all of them had surgery on their dominant side. Sudden pain developed at a mean 4 months (range, 0-6 months) after index surgery. The rapid progressive collapse of the humeral head occurred within 12 months after index surgery. No clear risk factor or evidence supporting an association between ARCS and humeral head osteonecrosis was found. CONCLUSIONS: Although the cause of the rapid progressive humeral head osteonecrosis after ARCS still needs to be established, surgeons should be aware of the possible development of humeral head osteonecrosis after ARCS, especially in older women with dominant arm involvement. LEVEL OF EVIDENCE: Level IV, prognostic case series.

Walch B0 glenoid: pre-osteoarthritic posterior subluxation of the humeral head.

The management of primary osteoarthritis of the shoulder has been well investigated. However, the etiology and management of posterior humeral head subluxation in the context of primary glenohumeral osteoarthritis remain controversial. The finding of static posterior subluxation of the humeral head before the development of posterior bone erosion of the glenoid in young men with radiographic findings of primary osteoarthritis has been described as arthrogenic posterior subluxation of the humeral head. It demonstrates the earliest form of the osteoarthritic evolution, and an excessive glenoid retroversion is the only probable cause of this static subluxation, although this is controversial. The clinical relevance of these findings is important in allowing the identification of patients at risk for development of glenohumeral osteoarthritis and in developing an early treatment for the subluxation to try to alter the natural course of this disease. The aim of our summary paper was to review the current literature on this matter in an attempt to better understand the pathophysiologic mechanism of this condition, which we named pre-osteoarthritic posterior subluxation of the humeral head, or Walch B-zero (B0) glenoid. It appears that Walch B0 glenoid is a pathologic condition (initially dynamic, eventually evolving into a static condition) that may lead to posterior erosion of the glenoid, taking place once there is asymmetric increased posterior glenohumeral contact forces and possibly associated with increased glenoid retroversion.

Early versus late repair of rotator cuff tears in rats.

BACKGROUND: In the event of a traumatic rotator cuff tear, patients are routinely advised that early surgical intervention produces an optimal repair, despite a lack of direct evidence to support this recommendation. To address this knowledge gap, massive rotator cuff tears in rats were assessed by biomechanical and bone morphometric analyses after early or late repair. METHODS: Combined supraspinatus and infraspinatus tendon tears of the left shoulder were created in 21 adult Wistar rats, which were divided into 2 groups. The tendons of the injured shoulder in the animals in group I were surgically repaired 8 weeks after the injury. Under the same anesthesia, the same injury was created on the right shoulder, which was immediately repaired. The rats from group I were euthanized 8 weeks after the repairs. No repair was performed in the rats from group II, which were euthanized 8 weeks after the injury. Tissues from both groups were harvested and biomechanically tested for supraspinatus tendon and bone morphometry analysis of the humeral head. RESULTS: All biomechanical properties were significantly increased in the early repair group compared with the late repair group. No significant differences were observed in bone morphometry of the humeral head when early and late repair groups were compared. CONCLUSION: Early surgical repair of a massive rotator cuff tear leads to improved biomechanical properties of the tissue after healing. Proximal humerus bone morphometry was unaffected by surgical repair timing.

Diagnosis and treatment of osteochondritis dissecans of the humeral capitellum.

Osteochondritis dissecans (OCD) of the humeral capitellum is a critical elbow injury in adolescent overhead throwing athletes. However, its etiology remains unknown. Medical examinations using ultrasonography found that the prevalence of capitellar OCD among adolescent baseball players was approximately from 1% to 3%. A plain anteroposterior radiograph with the elbow in 45° of flexion is essential for the diagnosis of an OCD lesion. The stability of OCD lesions is evaluated on plain radiographs, computed tomography, and magnetic resonance imaging (MRI). Imaging features of the unstable lesions are an epiphyseal closure of the capitellum or a lateral epicondyle, a displaced fragment, or irregular contours of the articular surface and a high signal interface on T2-weighted MRI. A stable lesion has the potential to be healed with conservative treatment. By contrast, surgical treatment should be considered if there is no radiographic improvement within 3 months. In addition, surgery should be performed for the lesions that cause pain during daily activities, have a locking phenomenon, or which are assessed by imaging as obviously unstable. Arthroscopic debridement/loose body removal can be performed for small lesions (≤12 mm in diameter). For large lesions (>12 mm), preservation and/or reconstruction of the articular surface should be selected, such as bone-peg fixation of the lateral part of the fragment and osteochondral autograft transplantation (OAT) from the knee. In the future directions, there is no comparative study of OAT from the knee and rib. In addition, little is known about its long-term outcome, or resulting osteoarthritis. A recent meta-analysis showed that grafts harvested from the knee may lead to donor site morbidity (7.8%). Thus, a novel cartilage tissue engineering approach is anticipated.

Posterior Decentering of the Humeral Head on Shoulder MR Arthrography: Significant Association With Posterior Synovial Proliferation.

OBJECTIVE: The purpose of this study is to analyze MRI findings associated with posterior decentering of the humeral head on shoulder MR arthrogram. MATERIALS AND METHODS: A total of 255 MR arthrograms were obtained during a 10-month period. MR arthrograms in patients with posterior decentering of the humeral head (n = 33) were reviewed and compared with those of randomly selected control group without posterior decentering (n = 66). MR arthrograms were retrospectively evaluated by two observers for posterior factors (posterior synovial proliferation, posterior capsular thickening, and posterior labral abnormality), rotator cuff factors related to fatty degeneration, glenoid version, and anterior factors (subcoracoid bursa effusion and rotator interval tear). The chi-square test, Fisher exact test, and linear-by-linear association were used for comparison of categoric data; the t test was used for comparison of the glenoid version; and multivariate stepwise logistic regression analysis was performed. RESULTS: At univariate analysis, posterior synovial proliferation (27.3% [9/33] in the posterior decentering group vs 6.1% [4/66] in the control group; p = 0.003); posterior capsule thickening (21.2% [7/33] vs 0.0% [0/66]; p < 0.001); fatty infiltration of the supraspinatus, infraspinatus, and teres minor (linear-by-linear association values, 7.944, 10.496, and 5.985, respectively; p = 0.005, 0.001, and 0.014, respectively); and rotator interval tear (51.5% [17/33] vs 30.3% [20/66]; p < 0.04) were more frequently found in the posterior decentering group, with a statistically significant difference. At multivariate analysis, only the posterior synovial proliferation was significantly associated with posterior decentering of the humeral head (odds ratio, 7.675; 95% CI, 2.159-27.288). CONCLUSION: Posterior decentering of the humeral head is most significantly associated with posterior synovial proliferation. In addition, rotator cuff interval abnormalities and rotator cuff atrophy are associated with posterior decentering of the humeral head to a lesser extent. Awareness of the association of the posterior decentering of the humeral head with the factors described here will facilitate the effective interpretation of routine MR arthrograms in daily practice.

Cost-benefit analysis of routine pathology examination in primary shoulder arthroplasty.

BACKGROUND: The annual number of shoulder arthroplasty procedures is continuing to increase. Specimens from shoulder arthroplasty cases are routinely sent for pathologic examination. This study sought to evaluate the clinical utility and associated costs of routine pathologic examination of tissue removed during primary shoulder arthroplasty cases and to determine cost-effectiveness of this practice. METHODS: This is a retrospective review of primary shoulder arthroplasty cases. Patients whose humeral head was sent for routine pathologic examination were included. Cases were determined to have concordant, discrepant, or discordant diagnoses based on preoperative/postoperative diagnosis and pathology diagnosis. Costs were estimated in 2015 U.S. dollars, and cost-effectiveness was determined by the cost per discrepant diagnosis and cost per discordant diagnosis. RESULTS: We identified 714 cases of primary shoulder arthroplasty in 646 patients who met inclusion criteria. The prevalence of concordant diagnoses was 94.1%, the prevalence of discrepant diagnoses was 5.9%, and no cases had discordant diagnoses. There were 172 cases that had biceps tendon specimens sent for pathology examination, and none led to a change in patient care. Total estimated costs were $77,309.34 in 2015 U.S. dollars. Cost per discrepant diagnosis for humeral head specimens was $1424.09, and cost per discordant diagnosis is at least $59,811.78. DISCUSSION/CONCLUSION: Primary shoulder arthroplasty has a high rate of concordant diagnosis. Discrepant diagnoses were 5.9% in our study, and there were no discordant diagnoses. This study showed limited clinical utility in routinely sending specimens from primary shoulder arthroplasty cases for pathology examination, and calculation using a traditional life-year value of $50,000 showed that the standard for cost-effectiveness is not met.

Three-dimensional quantitative analysis of humeral head and glenoid bone defects with recurrent glenohumeral instability.

BACKGROUND: Although bone defects of the humeral head and glenoid could affect glenohumeral instability, bone loss has not been sufficiently evaluated. The purpose of this study was to quantify bone defects 3-dimensionally in cases with glenohumeral instability. METHODS: Three-dimensional surface models of bilateral proximal humeri and glenoids were reconstructed from computed tomography scans of 90 patients with symptomatic, unilateral, recurrent glenohumeral instability. The left-side models were mirrored, and intact bone areas were matched to those of the right-side models. The volume, length, width, and depth of identified bone defects were assessed. After the values were corrected by patient height, the characteristics of the bone defects were evaluated. RESULTS: Bone defects were present in 97.8% of the humeral heads and 96.7% of the glenoids, and women had significantly smaller bone defects than men did. The volume of humeral head defects had a mild correlation with that of glenoid defects. The number of traumatic episodes was not correlated with humeral head bone defects, but it was positively correlated with glenoid bone defects. Patients with recurrent dislocations had significantly deeper and larger Hill-Sachs lesions than the other cases. CONCLUSION: Bone defects of the humeral head and the glenoid in cases with symptomatic traumatic glenohumeral instability were quantified 3-dimensionally using a computed tomography surface-matching technique. Almost all cases showed bone defects in the humeral head and glenoid compared with the intact shoulder, and such bone defects may be more common than previously reported. This study suggested that bipolar bone lesions are not always created by the same mechanism.

Interobserver and intraobserver variability of glenoid track measurements.

BACKGROUND: A method of assessing combined glenoid and humeral bone loss in traumatic shoulder instability with an associated treatment protocol was recently published. The aim of this study was to investigate its reliability and reproducibility. METHODS: Seventy-one patients with unilateral anteroinferior shoulder instability underwent computed tomography scans, from which 3-dimensional images were derived. En face views of both glenoid fossae and with 3 views of the humeral head were provided to 4 assessors to determine interobserver reliability. From these measurements, the shoulder was assigned a treatment classification. Two observers repeated their assessments 1 month later to determine intraobserver reliability. For each measurement, the mean coefficient of variability was calculated. RESULTS: Assessment of glenoid bone loss showed good interobserver (4 observers agreeing in 90.1% of cases) and also good intraobserver agreement (94% and 96%). There was a poor level of interobserver reliability regarding the on-track or off-track classification (72%). Intraobserver reliability for this measurement was less variable (90% and 80%). There was a poor level of agreement between observers (65%) regarding treatment classification. The coefficient of variability for the Hill-Sachs lesion measured 19.2%, indicating a high level of variability for this measurement compared with <4% for all other measures. CONCLUSION: Linear bone loss on the glenoid can be measured reliably and reproducibly; however, evaluation of Hill-Sachs lesions demonstrates a high level of variability, and poor interobserver reliability.