SciCombinator

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Concept: Coracoid process

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Acromioclavicular (AC) joint injuries vary in severity and damage to the AC and coracoclavicular (CC) ligaments. We hypothesized that transclavicular-transcoracoid drilling techniques, which allow for arthroscopic passage and fixation of tendon grafts in bone sockets to replace the insufficient conoid and trapezoid ligaments, cannot restore the footprints of the conoid and trapezoid ligaments without significant risk of cortical breach and coracoid fracture.

Concepts: Bone, Skeletal system, Anterior cruciate ligament, Joint, Ligament, Tendon, Clavicle, Coracoid process

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PURPOSE: The aim of this study was to define a safety margin for coracoid process osteotomy that does not compromise the coracoclavicular ligaments and that can be used in the coracoid transfer procedures. METHODS: Thirty shoulders from 15 cadavers were dissected, exposing the coracoid process and attached anatomic structures. The distance of the insertion of these structures to the coracoid process apex was measured. RESULTS: The average length of the coracoid process was 4.26 ± 0.26 cm. The average width and height at the tip were 2.11 ± 0.2 and 1.49 ± 0.12 cm, respectively. The average distance from the tip to the anterior and posterior margin of the pectoralis minor was 0.1 ± 1.17 and 1.59 ± 0.27 cm, respectively. The average distance from the tip to the posterior margin of the coracoacromial ligament was 2.79 ± 0.33 cm. The average distance from the apex to the most anterior part of the trapezoid ligament was 3.33 ± 0.38 cm. We obtained a constant value of 0.85 cm for this measure, and the value increased with each 1.0-cm increase in the distance from the tip to the posterior margin of the pectoralis minor. The safety margin for osteotomy (i.e., available bone distance for the coracoid process transfer) was 2.64 cm. CONCLUSIONS: This study established a safety margin of 2.64 cm for the osteotomy of the coracoid process and its relation with the posterior margin of the pectoralis minor. The anatomic descriptions of bone and soft tissue, as well as a measure of correlation for the safety margin of the coracoid, provide tools for surgeons performing anatomic surgical procedures to correct glenohumeral instability with significant bone loss. CLINICAL RELEVANCE: Knowing the safety margin allows the surgeon to perform a safe osteotomy without direct visualization of the coracoclavicular ligaments attachments, thereby making procedures more anatomic.

Concepts: Bone, Surgery, Anatomy, Length, Distance, Coracoid process, Coracoacromial ligament, Coracoclavicular ligament

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Study Design Cross-sectional. Objectives To compare differences in glenohumeral joint angular motion and linear translations between symptomatic and asymptomatic individuals during shoulder motion performed in 3 planes of humerothoracic elevation. Background Numerous clinical theories have linked abnormal glenohumeral kinematics including decreased glenohumeral external rotation and increased superior translation to individuals with shoulder pain and impingement diagnoses. However, relatively few studies have investigated glenohumeral joint angular motion and linear translations in this population. Methods Transcortical bone pins were inserted into the scapula and humerus of 12 asymptomatic and 10 symptomatic participants for direct bone-fixed tracking using electromagnetic sensors. Glenohumeral joint angular positions and linear translations were calculated during active shoulder flexion, abduction, and scapular plane abduction. Results Differences between groups in angular positions were limited to glenohumeral elevation coinciding with a reduction in scapulothoracic upward rotation. Symptomatic participants demonstrated 1.4 mm more anterior glenohumeral translation between 90 and 120° shoulder flexion and an average of 1 mm more inferior glenohumeral translation throughout shoulder abduction. Conclusion Differences in glenohumeral kinematics exist between symptomatic and asymptomatic individuals. The clinical implications of these differences are not yet understood and more research is needed to understand the relationship between abnormal kinematics, shoulder pain, and pathoanatomy. J Orthop Sports Phys Ther, Epub 7 August 2014. doi:10.2519/jospt.2014.5556.

Concepts: Biceps brachii muscle, Classical mechanics, Shoulder, Rotator cuff, Deltoid muscle, Coracoid process, Glenohumeral joint, Acromion

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Injuries to the acromioclavicular joint and coracoclavicular ligaments are common. Many of these injuries heal with nonoperative management. However, more severe injuries may lead to continued pain and shoulder dysfunction. In these patients, surgical techniques have been described to reconstruct the function of the coracoclavicular ligaments to provide stable relationship between the clavicle and scapula. These surgeries have been fraught with high complication rates including clavicle and coracoid fractures, infection, loss of reduction and fixation, hardware migration, and osteolysis. This article reviews common acromioclavicular and coracoclavicular repair and reconstruction techniques and associated complications, and provides recommendations for prevention and management.

Concepts: Bone, Joint, Shoulder, Clavicle, Coracoid process, Coracoclavicular ligament, Scapula, Acromion

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Recurrent anterior shoulder instability is associated with glenohumeral bone loss. Glenoid deficiency compromises the concavity-compression mechanism. Medial Hill-Sachs lesions can result in an off-track humeral position. Anterior glenoid reconstruction or augmentation prevents recurrence by addressing the pathomechanics. In Bristow and Latarjet procedures, the coracoid process is harvested for conjoint tendon transfer, capsular reinforcement, and glenoid rim restoration. Complications and the nonanatomic nature of the procedure have spurred research on graft sources. The iliac crest is preferred for autogenous structural grafts. Tricortical, bicortical, and J-bone grafts have shown promising results despite the historical association of Eden-Hybinette procedures with early degenerative joint disease. Allogeneic osteochondral grafts may minimize the risk of arthropathy and donor site morbidity. Tibial plafond and glenoid allografts more closely match the native glenoid geometry and restore the articular chondral environment, compared with conventional grafts. Graft availability, cost, risk of disease transmission, and low chondrocyte viability have slowed the acceptance of osteochondral allografts.

Concepts: Childbirth, Rheumatoid arthritis, Cartilage, Osteoarthritis, Shoulder, Ligament, Coracoid process, Scapula

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There is evidence that pectoralis minor (PM) length influences scapula position and that scapula position relates to glenohumeral joint (GHJ) external rotation (ER) range of motion (ROM).

Concepts: Shoulder, Coracoid process, Glenohumeral joint, Acromion

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The aim of this study was to determine the inter-rater reliability of glenohumeral internal rotation (GIR) range of motion (ROM) and pressure measurements among four measurement methods: (1) Manual stabilization of the humeral head and coracoid process (MSHC) without applying consistent pressure (ACP) to both the stationary and the moving arms (BSaMA); (2) MSHC with ACP to the moving arm; (3) MSHC with ACP to the stationary arm; and (4) MSHC with ACP to BSaMA.

Concepts: Measurement, Humerus, Psychometrics, Coracoid process, Scapula, Timeline of temperature and pressure measurement technology

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Simultaneous fracture of the acromion and coracoid process represents a double disruption of the superior shoulder suspensory complex (SSSC). To date, the two largest reported series have comprised five and eight cases. The aim of this study was to investigate the functional outcome in patients who sustained this rare injury and to provide a review of the relevant literature.

Concepts: Coracoid process, Glenohumeral joint, Scapula, Acromion

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Background/aim: The localization of the standard posterior portal of shoulder arthroscopy and landmarks mentioned in the literature are unclear. The purpose of this prospective cadaveric study was to determine the localization of the standard posterior portal and its distance to the neural structures. Materials and methods: One fresh frozen and 10 formalin-fixed adult cadaveric shoulders were dissected. In the beach chair position, a 5-mm trocar was placed anteroposteriorly from the superior edge of the subscapularis muscle, superior to the tip of the coracoid process and tangent to the glenoid. The relevant distances of the posterior exit point were measured. Results: In all specimens, the exit point was a triangular fibrous area, between the posterior and lateral parts of the deltoid. Medial and inferior distances of the trocar to the posterolateral tip of the acromion were 1.88 ± 0.53 cm and 1.35 ± 0.34 cm and distances to the axillary and suprascapular nerves were 4.54 ± 1.08 cm and 2.54 ± 0.85 cm, respectively. Conclusion: The most important finding of this study was the superficial localization of the soft spot between the posterior and lateral parts of deltoid.

Concepts: Shoulder, Supraspinatus muscle, Deltoid muscle, Axillary nerve, Coracoid process, Glenohumeral joint, Scapula, Acromion

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To perform a quantitative anatomic evaluation of the (1) coracoid process, specifically the attachment sites of the conjoint tendon, the pectoralis minor, the coracoacromial ligament (CAL), and the coracoclavicular (CC) ligaments in relation to pertinent osseous and soft tissue landmarks; (2) CC ligaments' attachments on the clavicle; and (3) CAL attachment on the acromion in relation to surgically relevant anatomic landmarks to assist in planning of the Latarjet procedure, acromioclavicular (AC) joint reconstructions, and CAL resection distances avoiding iatrogenic injury to surrounding structures.

Concepts: Sociology, Joint, Ligament, Clavicle, Coracoid process, Coracoacromial ligament, Coracoclavicular ligament, Acromioclavicular joint