Anatomical, functional and biomechanical review of the glenoid labrum

Almajed, Yousef A.; Hall, Andrew C.; Gillingwater, Thomas H.; Alashkham, Abduelmenem

doi:10.1111/joa.13582

Cited by 5 publications

(3 citation statements)

References 84 publications

(167 reference statements)

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“…All synovial joint surfaces are covered in a thin layer of hyaline cartilage between approximately 2 and 4 mm deep that, in conjunction with synovial fluid, facilitates low‐friction motion between articulating surfaces (Mow, Gu, & Chen, 2005; Sophia Fox, Bedi, & Rodeo, 2009). Some joints exhibit additional fibrocartilaginous elaborations (e.g., the labra of the shoulder and hip, the menisci of the knee), which are responsible for a combination of functional roles including load diffusion (Ahmed, Burke, & Yu, 1983; Fairbank, 1948; Fukubayashi & Kurosawa, 1980; Gee & Posner, 2021), enhancement of congruence between articular surfaces (Almajed, Hall, Gillingwater, & Alashkham, 2022; McDermott, Masouros, & Amis, 2008; Walker & Erkman, 1975), and stabilization of joint excursion (Almajed et al, 2022; Bendjaballah, Shirazi‐Adl, & Zukor, 1998; Levy, Torzilli, Gould, & Warren, 1989; Levy, Torzilli, & Warren, 1982; Shoemaker & Markolf, 1986). These additional cartilaginous structures vary in shape, size, and depth depending on the joint, and some synovial joints such as the elbow altogether lack such elaborations of fibrocartilage.…”

Section: Introductionmentioning

confidence: 99%

Covariance in human limb joint articular morphology

Horbaly

2023

American Journal of Biological Anthropology

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ObjectivesLimb synovial joints exhibit complex shapes that must accommodate often‐antagonistic demands of function, mobility, and stability. These demands presumably dictate coordination among joint articular shapes, but the structure of morphological covariance within and among joints is unknown. This study analyzes the human shoulder, elbow, hip, and knee to determine how articular covariance is structured in relation to joint structure, accessory cartilage, and function.Materials and MethodsSurface models were created from the CT scans of 200 modern skeletons from the University of Tennessee Donated Skeletal Collection. Three‐dimensional landmarks were collected on the shoulder, elbow, hip, and knee joints. Two‐block partial least squares were conducted to determine associations between surfaces of conarticular shapes, functionally analogous articulations, and articulations belonging to the same bone.ResultsExcept for the components of the shoulder, all conarticular pairs exhibit covariance, though the strength of these relationships appears unrelated to the amount of accessory cartilage in the joint. Only the analogous articulations of the humerus and femur exhibit significant covariance, but it is unlikely that this pattern is due to function alone. Stronger covariance within the lower limb than the upper limb is consistent broader primate patterns of within‐limb integration.DiscussionWith the exception of the elbow, complementary joint function does not appear to promote strong covariance between articulations. Analogous humeral and femoral surfaces are also serially homologous, which may result in the articular associations observed between these bones. Broadly, these patterns highlight the indirect relationship between joint congruence and covariance.

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Section: Introductionmentioning

confidence: 99%

Covariance in human limb joint articular morphology

Horbaly

2023

American Journal of Biological Anthropology

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“…The glenohumeral joint is the most mobile joint in the human skeleton, supported by dynamic and static stabilizers. 1 The glenoid labrum lines the glenoid rim and increases the depth of the glenoid fossa to provide increased stability. The labrum comprises fibrous connective tissue rather than cartilage, 4 although it may be fibrocartilaginous at the chondrolabral junction.…”

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confidence: 99%

The Buford Complex Redefined: A Pathologic Morphology in Sheep's Clothing

Scott,

Dwek,

Cheng

et al. 2024

Orthopaedic Journal of Sports Medicine

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Background: Considered a normal anatomic variant, the Buford complex has not been studied in children. Hypothesis: A Buford complex is not a normal anatomic variant and would, therefore, be present at a lower rate than that seen in the adult population. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Measurements were recorded from magnetic resonance imaging performed over 13 years in children aged ≤11 years for various pathologies unrelated to glenohumeral instability. Interrater reliability was determined to identify Buford complexes, sublabral foramens and tears, and normal shoulders via 16 preadolescent and adolescent patients with confirmed arthroscopic correlation. The Buford complex and labral foramen rates were then compared with a published rate in adults using a binomial probability test. Results: A total of 122 children (62 girls; mean age, 6.4 years [age range, 2 months-10.9 years]) were evaluated. Interrater reliability was 0.846 (95% CI, 0.56-1) to identify anterosuperior labral variants. The expected sublabral foramen count was 23 children, but only 1 was identified ( P < .001). The expected Buford complex count was 8 children, but none could be identified ( P < .001). Conclusion: The absence of Buford complexes and the significant reduction in sublabral foramen abundance in younger children suggest that these anatomic variants are more likely to be developmental than congenital. The distinct possibility that these previously considered normal variants are truly pathologic findings cannot be ignored. Evidence of a Buford complex could potentially signify an underlying, long-term shoulder instability issue to the treating provider that warrants further investigation or management.

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“…2,15 It provides stability to the glenohumeral joint by contributing approximately 50% of the depth of the glenoid and provides an attachment site for the glenohumeral ligaments anteriorly and posteriorly and the long head of biceps tendon superiorly, although their primary attachments are the supraglenoid tubercle and glenoid rim, respectively. 3,9 Tears can occur in the anterior labrum, superior labrum, posterior labrum, or any combination of the 3. 10,14 Pain is a common presenting feature of symptomatic labral tears, particularly superior labral anterior to posterior (SLAP) tears.…”

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confidence: 99%

Superior and Anterior Glenoid Labral Tears Are Associated With Increased Neurofilament Concentration

et al. 2023

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Background: Pain is a common presentation after glenohumeral labral injuries. However, the source of that pain is undetermined. Purpose/Hypothesis: We aimed to determine if there is a differential expression of nerve fibers around the glenoid labrum and if torn labra have increased neuronal expression compared with untorn labra (rotator cuff repair labra). We hypothesized that the superior labrum would have a higher concentration of neurofilament than would the rest of the labrum and that the concentration of neurofilament would increase at the site of a labral tear. Study Design: Descriptive laboratory study. Methods: Seven labra were sampled at the 3-, 5-, 9-, and 12-o’clock positions during total shoulder arthroplasty. Samples were also collected at the 3-, 5-, and 12-o’clock positions during rotator cuff repair (16 labra), anterior labral repair (6 labra), type II superior labral anterior to posterior (SLAP) repair (4 labra), and capsular release for idiopathic capsulitis (5 labra). Sections were immunostained with antibodies to neurofilament, a specific neuronal marker that is used to identify central and peripheral nerve fibers, and the concentration and intensity of immunostained-positive cells assessed. Results: The concentration of neurofilament staining was similar in the superior, anterior, posterior, and inferior glenoid labrum in untorn labra (8 neurofilament expressing cells per square millimeter; P = .3). Torn labra exhibited a 3- to 4-fold increase in neuronal expression, which was isolated to the location of the tear in SLAP ( P = .09) and anterior labral tears ( P = .02). The concentration of neurofilament expressing cells in torn glenoid labrum samples was comparable that in with the glenoid labrum of adhesive capsulitis samples ( P = .7). Conclusion: This study supports the hypothesis that after a tear of the anterior or superior labrum the labrum in that region becomes populated with new nerves fibers and that these fibers may be responsible for the pain noted by patients with superior (SLAP) and/or anterior labral (Bankart) tears. Clinical Relevance: This study suggests that neural infiltration contributes to the pain experienced by patients with labral tears. It may help with patient education and direct future management of labral lesions.

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Anatomical, functional and biomechanical review of the glenoid labrum

Cited by 5 publications

References 84 publications

Covariance in human limb joint articular morphology

Covariance in human limb joint articular morphology

The Buford Complex Redefined: A Pathologic Morphology in Sheep's Clothing

Superior and Anterior Glenoid Labral Tears Are Associated With Increased Neurofilament Concentration

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