Influence of coracoglenoid space on scapular neck fracture stability: biomechanical study

Background The anatomical variation of the coracoglenoid space has the potential to influence the stability of scapular neck fractures. This paper aimed to investigate the mechanical mechanism underlying the influence of different coracoglenoid space types on scapular neck fractures by morphometric analysis and biomechanical experiments. Methods The morphology of 68 dried scapulae (left: 36; right: 32) was studied. Two variables, the length of the coracoglenoid distance (CGD) and the coracoglenoid notch (CGN), were measured. The distribution of CGN/CGD × 100% was used to identify the morphology of the coracoglenoid space. Each specimen was tested for failure under static axial compression loading. The average failure load, stiffness, and energy were calculated. Results Two coracoglenoid space types were identified. The incidence of Type I (‘‘hook’’ shape) was 53%, and that of Type II (‘‘square bracket’’ shape) was 47%. The CGD and CGN were significantly higher for type I than type II (13.81 ± 0.74 mm vs. 11.50 ± 1.03 mm, P < 0.05; 4.74 ± 0.45 mm vs. 2.61 ± 0.45 mm, P < 0.05). The average maximum failure load of the two types was 1270.82 ± 318.85 N and 1529.18 ± 467.29 N, respectively (P = 0.011). The stiffness and energy were significantly higher for type II than type I (896.75 ± 281.14 N/mm vs. 692.91 ± 217.95 N/mm, P = 0.001; 2100.38 ± 649.54 N × mm vs. 1712.71 ± 626.02 N × mm, P = 0.015). Conclusions There was great interindividual variation in the anatomical morphology of the coracoglenoid space. Type I (hook-like) spaces bore lower forces, were less stiff, and bore less energy, which may constitute an anatomical predisposition to scapular neck fractures.

Influence of Coracoglenoid Space on the Stability of Scapular Neck Fractures: Biomechanical Study

Background: The anatomical variation of the coracoglenoid space has the potential to influence the stability of scapular neck fractures. This paper aimed to investigate the path-mechanical mechanisms of different types of coracoglenoid space on the scapular neck fractures by morphometric analysis and biomechanical experiments.Methods: A total of 68 dry scapulae (left: 36; right: 32) were collected, the types of coracoglenoid space delimited by a boundary based on the ratio of the mean values of CGD to the mean values of CGN. Each specimen of a different type was under static axial compressive load test to failure. The average failure loads, stiffness, and energy for each specimen were calculated.Results: Two types of coracoglenoid space were identified. The incidence of Type Ⅰ (2.4 < ratio ≤ 3.5) (‘‘hook’’ shape) was found to be 53%, that of Type Ⅱ (3.5 < ratio ≤ 5.0) (‘‘square bracket’’ shape) was found to be 47%. There was no statistically significant difference in the two types between different body sides (P > 0.05). The average maximum failure load of these two types was 1270.82 ± 318.85 N and 1529.18 ± 467.29 N, respectively (P = 0.011). The measures of the average failure stiffness and energy of Type Ⅱ were significantly higher than Type Ⅰ (896.75 ± 281.14 N/mm vs. 692.91 ± 217.9 5N/mm, P = 0.001; 2100.38 ± 649.54 N⋅mm vs. 1712.71 ± 626.02 N⋅mm, P = 0.015, respectively).Conclusions: The variation of coracoglenoid space is large in different individuals, hook-like space is associated with fewer forces, stiffness, and energy, which constitute an anatomical predisposition to the scapular neck fractures.

Infraglenoid fracture of the scapular neck − fact or myth?

In 1991, Ada and Miller described a new type of scapular neck fracture. It was a transverse fracture of the scapular body passing from the inferior border of the glenoid to the medial border of the scapular body (their type IIC). This fracture was later designated by Goss as a “fracture of neck inferior to scapula spine“. Since then, this type of fracture has been the cause of a number of controversies, mainly concerning the so-called “floating shoulder”. However, scapular neck fractures can be considered to be only those fractures that separate completely the glenoid from the scapular body. Term “fracture of neck inferior to scapula spine“ does not fit into this definition because it does not compromise the junction between the glenoid fossa and the scapular body. Actually, it is a transverse two-part fracture of the infraspinous part of the scapular body. As a result this term should no longer be used in the literature.

Muscle separation approach to scapular neck fractures in eight dogs

Summary Objectives: To report on a new surgical approach to scapular neck fractures. Methods: A combined prospective and retrospective study of eight dogs that had sustained a fracture of the scapular neck between 1992 and 2005 was performed. All eight dogs had an internal fixation using a T plate through a muscle separation approach. Retraction of the supraspinatus from the deltoideus and infraspinatus allows an adequate surgical window to enable plating of the scapular neck. Results: Sixty-two percent had an excellent outcome without any lameness or stiffness detected. The remaining cases experienced infrequent bouts of stiffness, or, in one case lameness. Clinical significance: The current literature recommends that the surgical approach to the scapular neck is by osteotomy of the acromion process, which is unnecessary in the authors’ opinion as it increases surgical trauma, operating time and the number of implants required.