Fractures around the hip: inducing life-like fractures as a basis for enhanced surgical training

Standardized fracture creation in the distal humerus and the olecranon for surgical training and biomechanical testing

INTRODUCTION

Surgical training and biomechanical testing require models that realistically represent the in vivo injury condition. The aim of this work was to develop and test a method for the generation of distal humerus fractures and olecranon fractures in human specimens, while preserving the soft tissue envelope.

METHODS

Twenty-one cadaveric upper extremity specimens (7 female, 14 male) were used. Two different experimental setups were developed, one to generate distal humerus fractures and one to generate olecranon fractures. Specimens were placed in a material testing machine and fractured with a predefined displacement. The force required for fracturing and the corresponding displacement were recorded and the induced energy was derived of the force-displacement graphs. After fracturing, CT imaging was performed and fractures were classified according to the AO classification.

RESULTS

Eleven distal humerus fractures and 10 olecranon fractures with intact soft tissue envelope could be created. Distal humerus fractures were classified as AO type C (n = 9) and as type B (n = 2), all olecranon fractures were classified as AO type B (n = 10). Distal humerus fractures required significantly more load than olecranon fractures (6077 N ± 1583 vs 4136 N ± 2368, p = 0.038) and absorbed more energy until fracture than olecranon fractures (17.8 J ± 9.1 vs 11.7 J ± 7.6, p = 0.11), while the displacement at fracture was similar (5.8 mm ± 1.6 vs 5.9 mm ± 3.1, p = 0.89).

CONCLUSION

The experimental setups are suitable for generating olecranon fractures and distal humerus fractures with intact soft tissue mantle for surgical training and biomechanical testing.

Substantial changes in fracture rates in German hospitals in 2018 compared with 2002: an epidemiological study

INTRODUCTION

The aim of this study was to present recent epidemiological data on extremity and axial skeletal fractures in German hospitals and to compare them with older data to detect time trends.

MATERIALS AND METHODS

Inpatient data from the German National Hospital Discharge Registry were used. The absolute number and age-standardized incidence of fractures in 2002 and 2018 were analysed by fracture location according to the International Classification of Disease. Data were analysed according to age group. Male: female ratios (MFRs) and incidence rate ratios (IRRs) were calculated to compare the 2018 and 2002 data.

RESULTS

The absolute number of fractures of the nine analysed locations was 15.2% higher in 2018 than in 2002. By fracture location, the changes were as follows (absolute change + IRR): "neck" (S12): + 172%, IRR = 2.6; "rib(s), sternum, thoracic spine" (S22): + 57%, IRR = 1.3; "lumbar spine and pelvis" (S32): + 66%, IRR = 1.3; "shoulder and upper arm" (S42): + 36%, IRR = 1.2; "forearm" (S52): + 13%, IRR = 1.0; "wrist and hand level" (S62): - 32%, IRR = 0.7; "femur" (S72): + 24%, IRR = 0.9; "lower leg, including ankle" (S82): - 24%, IRR = 0.7; "foot, except ankle" (S92): - 4%, IRR = 0.9. The overall MFR changed from 0.7 in 2002 to 0.6 in 2018. The age group of 45-54 years represented a turning point, males were more often affected than females in the younger age groups, and the opposite trend was observed in the older age groups.

CONCLUSIONS

The increase in the absolute fracture rates was due to increased rates of femur, shoulder, upper arm, forearm, and axial skeletal fractures, with elderly women being the main contributors. Femur fractures were found to be the most common fractures treated in German hospitals.

"Crack under pressure"-Inducing life-like mandible fractures as a potential benefit to surgical education in oral and maxillofacial surgery

The aim of this study was to investigate whether life-like fractures of human cadaveric mandibles with a focus on the condylar process and the intact soft tissue envelope could be simulated. A total of nine fresh-frozen human head specimens were fractured in a custom-made drop-test bench. This reproducible method is based on a weight falling from a defined height onto the fixed specimens, simulating a direct blow to the symphysis of the mandible. All the fractures were analyzed by fluoroscopy and CT-scans. In all the specimens that were included in this study, several typical lesions could be created, resulting in a total of 27 mandible fractures. Seven condylar head fractures with intracapsular fracture patterns, three high, two low and five subcondylar fractures as well as different corpus fractures occurred. Human cadaveric mandibles as part of a complete head specimen with intact soft tissue can be successfully fractured by means of a drop-test bench setup. The amount of load and the exact angle at which the load is applied seem to be of high relevance. Such fractured specimens can be implemented in surgical education courses to teach and improve osteosynthetic techniques.