The relationship between humeral head angulation and bone void within the humeral head in proximal humerus fractures.

Background: The variability of humeral head angulation in proximal humerus fractures (PHFs) is a noteworthy observation. The purpose of this study was to investigate the potential association between humeral head angulation and bone void within the humeral head in PHFs. Methods: We used the reconstruction function in Mimics software to generate three-dimensional models of fractures. Bony landmarks were employed to accurately define the calcar and humeral head zone. Boolean subtraction was performed to calculate the volume of head bone void. Results: The cohort consisted of 60 (74.1 %) varus, 21 (25.9 %) valgus, and 23 (22.1 %) neutral angulated PHFs. The mean percentage of humeral head bone void was 38.5 ± 17.8 in varus, 36.3 ± 15.7 in valgus, and 30.1 ± 10.6 in neutral angulated PHFs. A significant difference was observed between the varus and neutral groups (P = 0.035). In addition, an analysis of humeral head bone void was conducted among patients aged over 65 years old, revealing a mean percentage of 42.7 ± 16.4 in varus (27 cases), 34.8 ± 14.5 in valgus (13 cases), and 28.1 ± 11.8 in neutral (8 cases) angulated PHFs. The difference between the varus and neutral groups was also significant (P = 0.023). Conclusion: All types of angulation patterns exhibited humeral head bone void to some extent, with the varus-displaced PHFs demonstrating more obvious defects in comparison to the neutral angulated type.

Transcriptome sequencing reveals inflammation and macrophage heterogeneity in subacromial bursa from degenerative shoulder disorders.

PURPOSE: We aimed to investigate the transcriptomic alterations that occur in the subacromial bursa (SAB) following degenerative or traumatic shoulder diseases. MATERIALS AND METHODS: RNA sequencing was employed to evaluate the transcriptomic alterations of the SAB in individuals afflicted with degenerative rotator cuff tear (RCT), traumatic RCT and proximal humerus fracture (PHF). To gain insights into the biological significance of differentially expressed genes (DEGs), we conducted an enrichment analysis utilizing Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. We further utilized single-cell RNA sequencing datasets of SAB from a recently published study to explore the associated cellular dynamics and alterations. RESULTS: We detected 1,790 up-regulated and 1,964 down-regulated DEGs between degenerative RCT and PHF, 2,085 up-regulated and 1,919 down-regulated DEGs between degenerative RCT and traumatic RCT, and 20 up-regulated and 12 down-regulated DEGs between traumatic RCT and PHF. Given the similar expression pattern between traumatic RCT and PHF, they were integrated as the traumatic group. In comparison with the traumatic group, 1,983 up-regulated and 2,205 down-regulated DEGs were detected in degenerative SAB. Enrichment analysis of up-regulated DEGs uncovered an elevated inflammatory and immunologic responses in degenerative SAB. Single-cell transcriptomic analysis revealed macrophage represented the immune cell with the most DEGs between the degenerative and traumatic RCT. CONCLUSION: Our results revealed that the SAB in degenerative RCT exhibited a different transcriptional signature compared to that in traumatic RCT, and enrichment analysis showed immunologic and inflammatory activations. Macrophages may play a fundamental role in this process.

The Relationship Between Shoulder Impingement Syndrome and Coracoacromial Ligament Degeneration a Predictive Factor for Shoulder Acromioplasty.

Objective: The coracoacromial ligament (CAL) connects the acromion and coracoid process of the scapula. This study aimed to explore the correlation between CAL degeneration and shoulder pathology, specifically focusing on the efficacy of acromioplasty in treating shoulder impingement in patients with varying degrees of CAL degeneration. Methods: 49 patients diagnosed with bursal-side partial rotator cuff tear were assessed for CAL degeneration and categorized into three grades. They were then randomized into acromioplasty and non-acromioplasty groups to compare the outcomes. Acromiohumeral distance (AHD) and fatty infiltration was evaluated on imaging examinations. American Shoulder and Elbow Score (ASES) and Visual Analogue Scale (VAS) was recorded to evaluate the shoulder function before and two years after surgery. Results: Grade III CAL patients demonstrated significantly reduced AHD and increased VAS scores compared to Grades I and II. Post-acromioplasty, Grade III patients showed a statistically significant improvement in ASES scores compared to the non-acromioplasty group. Conclusion: The study indicates that CAL degeneration is a significant indicator of shoulder impingement. Notably, acromioplasty significantly improves shoulder function in patients with severe CAL degeneration, suggesting its potential as a targeted treatment in managing shoulder impingement.

State transition and intercellular communication of synovial fibroblasts in response to chronic and acute shoulder injuries unveiled by single-cell transcriptomic analyses.

PURPOSE: We aimed to investigate the heterogeneity of synovial fibroblasts and their potential to undergo cell state transitions at the resolution of single cells. MATERIALS AND METHODS: We employed the single-cell RNA sequencing (scRNA-seq) approach to comprehensively map the cellular landscape of the shoulder synovium in individuals with chronic rotator cuff tears (RCTs) and acute proximal humerus fractures (PHFs). Utilizing unbiased clustering analysis, we successfully identified distinct subpopulations of fibroblasts within the synovial environment. We utilized Monocle 3 to delineate the trajectory of synovial fibroblast state transition. And we used CellPhone DB v2.1.0 to predict cell-cell communication patterns within the synovial microenvironment. RESULTS: We identified eight main cell clusters in the shoulder synovium. Unbiased clustering analysis identified four synovial fibroblast subpopulations, with diverse biological functions associated with protein secretion, ECM remodeling, inflammation regulation and cell division. Lining, mesenchymal, pro-inflammatory and proliferative fibroblasts subsets were identified. Combining the results from StemID and characteristic gene features, mesenchymal fibroblasts exhibited characteristics of fibroblast progenitor cells. The trajectory of synovial fibroblast state transition showed a transition from mesenchymal to pro-inflammatory and lining phenotypes. In addition, the cross talk between fibroblast subclusters increased in degenerative shoulder diseases compared to acute trauma. CONCLUSION: We successfully generated the scRNA-seq transcriptomic atlas of the shoulder synovium, which provides a comprehensive understanding of the heterogeneity of synovial fibroblasts, their potential to undergo state transitions, and their intercellular communication in the context of chronic degenerative and acute traumatic shoulder diseases.

Fracture Line Morphology of Greater Tuberosity Fragments of Neer Three- and Four-Part Proximal Humerus Fractures.

OBJECTIVE: In complicated Neer three- and four-part proximal humerus fracture (PHF), greater tuberosity (GT) fragments are often comminuted, and the currently widely used locking plate may not fix GT fragments effectively. A further understanding of morphological characteristics of the GT fragments may help explore new fixation devices. This study aimed to determine the fracture line morphology of the GT fragment of Neer three- or four-part PHF and analyze the location relationship between the locking plate and the GT fragment. METHODS: Seventy-one three-dimensional computed tomography scans of Neer three- and four-part PHF were retrospectively reviewed between January 2014 and June 2019. Fracture fragments were reconstructed and virtually reduced in the Mimics software, and fracture lines of GT fragments were depicted on a humerus template in the 3-matic software and then were superimposed altogether. The common sites of the GT fracture were identified, and the location relationship between the locking plate and GT fragments was analyzed in a computer-simulated scenario. RESULTS: The fracture line morphology of GT fragments was similar between Neer three- and four-part PHF. The overall morphology of GT fragments was in a fan shape, which could be summarized as anterior, superior, posterior, and middle lines. Of these, we identified 51 split and 29 avulsion type GT fragments based on the Mutch classification, and they could occur simultaneously in a PHF. The overall morphology of split type fragments was in a fan shape, and avulsion type fragments showed a quite distinguishable distribution pattern. A GT fragment could be classified as anterior-split, posterior-split, complete-split, anterior -avulsion, and posterior-avulsion type based on its morphology and location. The median percentage of fragment area covered by the plate was 32.3% in all of the fragments, and it was 69.4%, 23.0%, 37.2%, 21.8%, 0.0% in anterior-split, posterior-split, complete-split, anterior-avulsion, and posterior-avulsion type GT fragments. We defined the posterior-split, anterior-avulsion, and posterior-avulsion type GT fragments as the risky GT fragments, and they occurred in 43 (60.6%) Neer three- and four-part PHFs. CONCLUSION: The fracture line morphology of GT fragments of Neer three- and four-part PHF was in a fan shape. GT fragments could be classified based on their location and morphology. The extent of GT fragment coverage provided by the locking plate differed in various fragment types, and we identified the anterior-avulsion, posterior-avulsion, and posterior-split type fragments as the risky GT fragments with a high incidence rate in Neer three- and four-part PHFs.

A Transosseous Suture as an Alternative to Suture Anchor on Anterior-Avulsion Greater Tuberosity Fragment Fixation in Neer Three-Part Proximal Humeral Fracture: A Biomechanical Study.

OBJECTIVE: Greater tuberosity (GT) fragments were communicated, and additional techniques to increase the GT fragment stability after the locking plate fixation was necessary. This study aimed to analyze the reinforcement effects on the anterior-avulsion GT fragment in Neer three-part proximal humeral fractures (PHFs) using transosseous suture and suture anchor techniques. METHODS: Eighteen fresh-frozen human cadaveric shoulder specimens were used in the study. Standardized fracture of the GT and surgical neck was created in 18 human cadaveric proximal humerus. The GT fragments were reinforced with transosseous suture (TS), suture anchor (SA), and suture in addition to the PHILOS plate fixation. The fixed humerus was tested by applying static loading to the supraspinatus tendon. Load forces and fragment displacement were evaluated by a biomechanical testing machine, and the load to 3- and 5-mm displacements, load to failure, and mode of failure were recorded for all specimens. Nonparametric variables were examined by the Kruskal-Wallis test, and the Bonferroni post hoc test was used to analyze the mean loads to create 3- and 5-mm displacements as well as the failure load. RESULTS: The age, female proportion, and bone mineral density showed no statistically significant differences between the three groups. The mean loading force to create 3-mm and 5-mm displacement in the TS group (254.9 ± 77.4, 309.6 ± 152.7) were significantly higher than those in the suture group (136.1 ± 16.7, 193.4 ± 14.5) (P = 0.024, P = 0.005). For the SA group, the force to create 3- and 5-mm displacement (204.3 ± 60.9, 307.8 ± 73.5) were comparable to those in the TS group (P = 0.236, P = 0.983). Moreover, the loading force to failure in the TS group (508.6 ± 217.7) and SA group (406.6 ± 114.9) was significantly higher than that in the suture group (265.9 ± 52.1) (P = 0.021, P = 0.024). In the TS group, three failed due to tendon-bone junction rupture; bone tunnel broken occurred in two specimens; suture rupture could also be seen in one specimen. All specimens in the suture group failed because of suture rupture. In the SA group, three specimens failed due to suture rupture; two failed secondary to tendon-bone junction rupture; and one failed because of shaft fracture. CONCLUSIONS: Transosseous suture is a new type of reinforcement for GT fragment in Neer-three part PHFs. The transosseous suture was superior to the suture only in the reinforcement of the anterior-avulsion GT fragment of Neer three-part PHFs, and it had comparable biomechanical strength to the suture anchor.

Tuberosity reconstruction baseplate for shoulder hemiarthroplasty: Morphological design and biomaterial application.

Background: Shoulder hemiarthroplasty is prone to tuberosity malposition and migration, reducing the rate of tuberosity healing. We proposed to design a tuberosity reconstruction baseplate to assist in tuberosity integration and to evaluate the mechanical properties of baseplate made from the novel biomaterial carbon fiber reinforced polymer (CFRP) composites. Methods: The three-dimensional model of native proximal humerus was constructed by computed tomography (CT) data. The morphological design of baseplate was based on the tuberosity contour and rotator cuff footprint. Finite element models were created for different thicknesses of CFRP composites, poly (ether-ether-ketone) (PEEK) and titanium-nickel (TiNi) alloy. The permissible load and suture hole displacements were applied to evaluate the mechanical properties. Results: The structurally optimized model made of CFRP composites provided superior strength and deformability, compared to the PEEK material and TiNi alloy. Its permissible load was above 200 N and the suture hole displacement was between 0.9 and 1.4 mm. Conclusion: This study proposed a method for designing tuberosity reconstruction baseplate based on morphological data and extended the application of biomaterial CFRP composites in orthopedics field. The optimized model made of CFRP composites allowed a certain extent of elastic deformation and showed the possibility for dynamic compression of tuberosity bone blocks.

Relevance between Proximal Humeral Migration and Rotator Cuff Tears.

Background: Proximal humeral migration is common in patients with rotator cuff tears. In this study, we aimed to evaluate the relevance between proximal humeral migration and some rotator cuff tear-related factors. Methods: A total of 75 patients with unilateral rotator cuff tears were retrospectively included from August 2016 to January 2018 who underwent magnetic resonance imaging and X-ray examinations before enrollment. We introduced the upward migration index (UMI) to stratify the patients into three groups, Group A: 1 < UMI ≤ 1.3; Group B: 1.3 < UMI ≤ 1.4; and Group C: UMI > 1.4. Pearson correlation analysis and logistic regression analysis were used to evaluate the relationship between UMI and age, sex, body mass index, pain, fatty degeneration grade, tear size, and thickness of ruptured tendon. Then, the χ 2 test and receiver operator characteristic curve were applied to measure the diagnostic value of UMI. Results: The average UMI was 1.34 ± 0.07, ranging from 1.16 to 1.48. For the Pearson correlation analysis, there was a negative correlation between UMI and tear size (R = -0.68, p < 0.01), and also, there was a negative correlation between UMI and the visual analogue scale score (R = 0.342, p < 0.01). What is more, there was a negative correlation between UMI and the fatty degeneration grade (R = -0.373, p < 0.01). Ordinal multinomial logistic regression analysis indicated that tear size (ß = -1.825, p < 0.001) was the independent predictor of UMI, which was a risk factor for humeral upward migration. The cutoff points of UMI were 1.38 and 1.3 to determine tears and distinguish large tears from small ones. Conclusions: UMI is a good predictor for humeral upward migration, which is related to the tear size of posterosuperior cuff tears. When the UMI is <1.3, a large tear should be alerted. Combining physical examination and X-ray is helpful for evaluating rotator cuff tears.

WITHDRAWN: Fracture line morphology of greater tuberosity fragments of Neer 3 and 4 part proximal humerus fractures.

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GSK3ß inhibition accelerates axon debris clearance and new axon remyelination.

Glycogen synthase kinase 3ß (GSK3ß) inhibitors, especially the mood stabilizer lithium chloride, are also used as neuroprotective or anti-inflammatory agents. We studied the influence of LiCl on inducing early myelin clearance and on regulating the remyelination following peripheral nerves injury. We showed that the oral administration of adult mice with LiCl after sciatic nerve crush injury accelerated in vivo myelin debris clearance stimulated the expression of myelin proteins, restored the myelin structure, and accelerated the recovery of sciatic functions. LiCl treatment also promoted remyelination of the sciatic nerve after crush. Furthermore, we also demonstrated that LiCl exerts its action in Schwann cells by increasing the amount of ß-catenin and provoking its nuclear localization in vivo. We showed by ChIP experiments that LiCl treatment drives ß-catenin to bind to T-cell factor/lymphoid-enhancer factor response elements identified in myelin-related genes. Taken together, our results provide the first evidence that the GSK3ß could be considered as an important drug in inducing early myelin debris clearance and regulating the expression of myelin genes, which open new approaches in the clinical treatment of nerve injuries by utilizing GSK3ß inhibitors such as lithium.

Radiological characteristics and anatomical risk factors in the evaluation of hallux valgus in chinese adults.

BACKGROUND: There are no unified theories as to the anatomical changes that occur with hallux valgus, we investigated the radiological characteristics and anatomical risk factors for hallux valgus deformity in Chinese adults. METHODS: We reviewed 141 patients with hallux valgus (206 feet; 15 males, 126 females; mean age, 58.5 years). These patients attended Peking University People's Hospital from April 2008 to March 2014. All feet had intact radiological data, obtained using the Centricity RIS/PACS system. We measured hallux valgus angle (HVA), 1-2 intermetatarsal angle (IMA), proximal articular set angle (PASA), distal articular set angle, hallux interphalangeal angle, metatarsocuneiform angle, size of the medial eminence of the distal first metatarsal, tibial sesamoid position, and joint congruity of the first metatarsophalangeal joint (MTPJ). RESULTS: We found positive correlations between the HVA and IMA (r = 0.279, P < 0.01) and HVA and PASA (r = 0.358, P < 0.01), but not for IMA and PASA (P > 0.05). Feet were divided into three groups based on HVA severity. IMA (P < 0.05) and PASA (P < 0.05) in the mild group were significantly lower than that in the moderate and severe groups, with no significant difference determined for IMA or PASA between the moderate and severe groups (P > 0.05). Feet were then grouped based on the shape of the first metatarsal head. Using this grouping, HVA was significant higher in the rounded shape (19.92°) than in a flat shape (17.66°). The size of the medial eminence of the distal first metatarsal was positively correlated with HVA (r = 0.185, P < 0.01). The medial eminence in the moderate and severe groups was significantly larger than that in the mild group; moderate and severe groups were not significantly different. CONCLUSIONS: PASA enlargement is an adaptive change during early hallux valgus formation, and decompensation leads to subdislocation in the first MTPJ. A rounded first metatarsal head would thus predispose a foot to hallux valgus. Furthermore, bone proliferation at the medial eminence may also lead to early hallux valgus development.