Anatomical study of the clavicle: endomedullary morphology

Effect of different loads on the shoulder in abduction postures: a finite element analysis

Load can change the mechanical environment of dynamic and static stable structures of the shoulder joint, increase the risk of tissue damage and affect the stability of the shoulder joint, but its biomechanical mechanism is still unclear. Therefore, a finite element model of the shoulder joint was constructed to analyze the mechanical index changes of shoulder joint abduction under different loads. The stress of the articular side on the supraspinatus tendon was higher than that of the capsular side, with a maximum difference of 43% due to the increased load. For the deltoid muscle and glenohumeral ligaments, increases in stress and strain were obvious in the middle and posterior deltoid muscles and inferior glenohumeral ligaments. The above results indicate that load increases the stress difference between the articular side and the capsular side on the supraspinatus tendon and increases the mechanical indices of the middle and posterior deltoid muscles, as well as the inferior glenohumeral ligament. The increased stress and strain in these specific sites can lead to tissue injury and affect the stability of the shoulder joint.

Morphometric Analysis of Clavicle and Its Medullary Canal: A Computed Tomographic Study

BACKGROUND

Intramedullary fixation is one of the common methods of treating clavicle fractures. Morphometric data of the clavicle and its medullary canal will help design a better device and surgical technique. Morphometric studies on clavicle are sparse; hence, this study.

METHODS

A 3-D reconstruction of 64 clavicles of 32 patients was done from computed tomography (CT) scan data of thorax obtained for the diagnostic workup of unrelated disease. The various dimensions of the clavicle and its medullary canal were measured. The narrowest part, point of change of direction of the medullary canal, curvatures of the clavicle, the position of the coracoid process, and the relation of these features to eight equally divided segments of clavicle were noted.

RESULTS

The average length of the clavicle was 142.5 mm. The average height and width of the narrowest part of the medullary canal were 2.4 mm and 2.5 mm, respectively, corresponding to segment 5 (S5) in more than half of the clavicles. The change of direction of the medullary canal and the medial edge of the coracoid process were corresponding to segment 6 (S6) in the majority of the clavicles.

CONCLUSION

This computed tomographic study provides morphometric data of the clavicle applicable to intramedullary fixation of clavicle fractures. In the studied population, the clavicles were shorter, more curved, and had medullary canal dimensions less than 2.5 mm at the narrowest part. This may pose difficulties in intramedullary fixation. The coracoid process was a reliable anatomical landmark.

The variance of clavicular surface morphology is predictable: an analysis of dependent and independent metadata variables

Background

The anatomy of the clavicle is specific and varied in reference to its topography and shape. These anatomic characteristics play an important role in the open treatment of clavicle fractures. The complex and variable topography creates challenges for implant placement, contouring, and position. Hardware prominence and irritation does influence the decision for secondary surgical intervention.

Methods

Computerized tomographic scans of 350 adult clavicles with the corresponding patients' metadata were acquired and digitized. Morphologic parameters determining the shape of the clavicle were defined and computed for each digitized bone. The extracted morphologic parameters were correlated with patient metadata to analyze the relationship between morphologic variability and patient characteristics.

Results

The morphologic parameters defining the shape, that is, the radius of the medial and lateral curves, the apparent clavicle height and width, and the clavicle bow position, correlate with the clavicle length. The clavicle length correlates with the patients' height. Gender differences in shape and form were dependent and related to individual height distribution and clavicle length. Asian populations showed a similarly predictable, but shifted, correlation between shape and clavicle length.

Conclusion

This anatomic analysis shows that the clavicle shape can be predicted through the clavicle length and patients' stature. Smaller patients have shorter and more curved clavicles, whereas taller patients have longer and less curved clavicles. This correlation will aid surgeons in fracture reduction, implant curvature selection, and in optimal adaptation of clavicle implants, and represents the basis for anatomically accurate solutions for clavicle osteosynthesis.

A computed tomography study of the fibula: morphology, morphometry, intramedullary anatomy, application prospects on intramedullary nailing

PURPOSE

The intramedullary percutaneous pinning in fractures of the lateral malleolus is a technique of osteosynthesis that can reduce complications of ORIF. Our study describes the morphology and the morphometry of the fibula, in particular intramedullary, so as to specify the best fibular nail features.

METHODS

We conducted a retrospective study on CT acquisitions of fibulae in vivo. We studied total length, and the distal malleolar angle. Regarding intramedullary morphology, six axial study levels were defined. Each level was assigned a morphometric classification (oval, triangular, quadrangular or irregular), and a measure of the diameter of the cavity. The distance between the smaller diameter and the malleolar tip was investigated.

RESULTS

We included 50 patients for 97 fibulae. The average age was 66.5 years. The irregular morphology type was the most frequently found. The average length was 370.5 mm (SD = 18.1; CI 95% [366.9; 374.1]), the average distal malleolar angle was 163.5° (SD = 3.7; CI 95% [162.7; 164.2]). The average minimal intramedullary diameter at malleolus level was 3.2 mm (SD = 1.2; CI 95% [3.0; 3.5]), with a minimum size reaching 95.8 mm (SD = 13.8; CI 95% [93.0; 98.5]) of the malleolar tip.

CONCLUSIONS

The analysis of morphological parameters of the fibula, in particular the lateral malleolus and intramedullary morphology is necessary for the design of a morpho-adapted nail. Interpersonal variability must be taken into account by the implant industry to offer nails of suited lengths and diameters.

Morphometry of the human clavicle and intramedullary canal: A 3D, geometry-based quantification

Midshaft clavicle fractures are a very common occurrence. The current treatment of choice involves internal fixation with superior or anterior clavicle plating, however their clinical success and particularly patient satisfaction are decreasing. The implementation of intramedullary devices is on the rise, but data describing the intramedullary canal parameters are lacking. The aim of this study is to quantify the geometry of the clavicle and its intramedullary canal, and to evaluate the effect of gender and anatomical side. This study used three-dimensional image-based models with novel and automated methods of standardization, normalization, and bone cross-section evaluation. The data obtained in this study present intramedullary canal, and clavicle diameter and center deviation parameterized as a function of clavicle length as well as its radius of curvature and true length. Results showed that both right-sided and female clavicles were shorter and thicker, but only females showed a statistically significant difference in size compared to males (p < 0.0001). The smallest clavicle and intramedullary canal diameters were seen at different clavicle lengths (45% and 52%), suggesting that the narrowest region of intramedullary canal cannot be appreciated based on external visualization of the clavicle alone. The narrowing of the intramedullary canal is of special interest because this is a potential limiting region for surgical planning and intramedullary device design. Furthermore, the location and value of maximum lateral curvature displacement is different in the intramedullary canal, implying there exists an eccentricity of the intramedullary canal center with respect to the clavicle center. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2191-2202, 2017.

Clavicular Refracture at the Site of Angular Malunion in Young Athletes

OBJECTIVE

The treatment of midshaft clavicle fractures has, in the last 2 decades, shifted markedly towards operative management. Prospective trials have defined accepted clinical and radiographic indications for the surgical management of clavicle fractures. This report documents 3 cases of clinically united angular malunion of the midshaft clavicle in young athletes that subsequently refractured to highlight angular deformity in the absence of displacement as a potential indication for surgical fixation.

DESIGN

Case series.

SETTING

A level 1 trauma centre.

PATIENTS/PARTICIPANTS

Three young athletic patients with angular malunion of the midshaft clavicle who experienced refracture, requiring surgical fixation.

INTERVENTION

Surgical fixation of midshaft clavicle fracture, as treatment for refracture after angular malunion.

RESULTS

All 3 patients required subsequent surgical fixation of their midshaft clavicle fracture, correcting the angular malunion and restoring shoulder function.

CONCLUSIONS

Midshaft clavicular fractures that malunite with significant angulation in the absence of displacement represent a risk for subsequent refracture. For this reason, angular deformity should be considered as a potential indication for surgical fixation in acute clavicular fractures.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Midshaft Clavicle Fractures: A Critical Review

The clavicle is the most commonly broken bone in the human body, accounting for up to 5% to 10% of all fractures seen in hospital emergency admissions. Fractures of the middle third, or midshaft, are the most common, accounting for up to 80% of all clavicle fractures. Traditional treatment of midshaft clavicle fractures is usually nonoperative management, using a sling or figure-of-eight bandage. The majority of adults treated nonoperatively for midshaft clavicle fractures will heal completely. However, newer studies have shown that malunion, pain, and deformity rates may be higher than previously reported with traditional management. Recent evidence demonstrates that operative treatment of midshaft clavicle fractures can result in better functional results and patient satisfaction than nonoperative treatment in patients meeting certain criteria. This article provides a review of relevant anatomy, classification systems, and injury mechanisms for midshaft clavicle fractures, as well as a comparison of various treatment options. [Orthopedics.2016; 39(5):e814-e821.].

Anatomical Study of the Clavicles in a Chinese Population

BACKGROUND

A reemergence of interest in clavicle anatomy was prompted because of the advocacy for operative treatment of midshaft clavicle fractures. Several anatomical studies of the clavicle have been performed in western population. However, there was no anatomical study of clavicle in Chinese population.

PATIENTS AND METHODS

52 patients were included in the present study. Three-dimensional reconstructions of the clavicles were generated. The length of the clavicle, the widths and thicknesses of the clavicle, curvatures of the clavicle, the areas of the intramedullary canal, and sectional areas of the clavicle were measured. All the measurements were compared between genders and two sides.

RESULTS

The mean length of the clavicles was 144.2 ± 12.0 mm. Clavicles in males were longer, wider, and thicker than in females; also males have different curvatures in both planes compared with females. The men's intramedullary canals and sectional areas of the clavicle were larger than those of women. No significant difference between the sides was found for all the measurements.

CONCLUSION

This study provided an anatomical data of the clavicle in a Chinese population. These clavicle dimensions can be applied to the modifications of the contemporary clavicle plate or a new development for the Chinese population.

Measurement of clavicular length and shortening after a midshaft clavicular fracture: Spatial digitization versus planar roentgen photogrammetry

PURPOSE

Clavicular shortening after fracture is deemed prognostic for clinical outcome and is therefore generally assessed on radiographs. It is used for clinical decision making regarding operative or non-operative treatment in the first 2weeks after trauma, although the reliability and accuracy of the measurements are unclear. This study aimed to assess the reliability of roentgen photogrammetry (2D) of clavicular length and shortening, and to compare these with 3D-spatial digitization measurements, obtained with an electromagnetic recording system (Flock of Birds).

PATIENTS AND METHODS

Thirty-two participants with a consolidated non-operatively treated two or multi-fragmented dislocated midshaft clavicular fracture were analysed. Two observers measured clavicular lengths and absolute and proportional clavicular shortening on radiographs taken before and after fracture consolidation. The clavicular lengths were also measured with spatial digitization. Inter-observer agreement on the radiographic measurements was assessed using the Intraclass Correlation Coefficient (ICC). Agreement between the radiographic and spatial digitization measurements was assessed using a Bland-Altman plot.

RESULTS

The inter-observer agreement on clavicular length, and absolute and proportional shortening on trauma radiographs was almost perfect (ICC>0.90), but moderate for absolute shortening after consolidation (ICC=0.45). The Bland-Altman plot compared measurements of length on AP panorama radiographs with spatial digitization and showed that planar roentgen photogrammetry resulted in up to 37mm longer and 34mm shorter measurements than spatial digitization.

CONCLUSION

Measurements of clavicular length on radiographs are highly reliable between observers, but may not reflect the actual length and shortening of the clavicle when compared to length measurements with spatial digitization. We recommend to use proportional shortening when measuring clavicular length or shortening on radiographs for clinical decision making.