Intrathoracic migration of a K-wire after percutaneous fixation of a proximal humerus fracture

Does minimally invasive external fixation of proximal humerus fractures provide adequate stability? A biomechanical in vitro study

INTRODUCTION

Proximal humerus fractures are usually treated with rigid angle-stable plates or nails. As an alternative, semi-rigid, minimally invasive systems have been developed for supportive fixation. A new system uses this principle with 2.5 mm partially threaded pins and external fixation.

AIM

This study aimed to compare the fracture stability of the fixator with an angular stable plate about whether the mechanical stability is sufficient for early postoperative mobilisation.

MATERIALS AND METHODS

Human proximal humeri (paired, female, age ≥ 60, n = 8) were cut to a 3-part fracture and treated with an external fixator (Galaxy Shoulder, Orthofix) or an angular stable plate (Philos, DePuy Synthes). A physiological load was simulated in vitro based on a 45° abduction motion. The load level was continuously increased from 10 to 320 N within 10,000 cycles simulating the loads during rehabilitation. This was followed by another 10,000 cycles at 320 N for fatigue testing. Fracture motion was recorded with a 3D camera. Fracture stability was evaluated at a partial load of 160 N and 240 N (simulating loads during early mobilisation).

RESULTS

The fracture motion at the lateral aspect was significantly (p < 0.034) larger for the fixator compared to the plate both for axial and for shear movements, while at the medial aspects fracture motions were similar. Both fixation systems adequately stabilized the lateral tubercle fragment with no significant differences between fixation techniques. The migration of the fixator pins (1.1 ± 1.0 mm) and valgus rotation of the head fragment were minimal (3.1 ± 2.0°). The maximum load level of 320 N was reached by all plate constructs and 3 fixator constructs.

CONCLUSION

Our results suggest that the external fixator system allows early but gentle postoperative mobilisation. More aggressive rehabilitation measures should be postponed after the healing of the fracture.

Intracardic migration of Kirschner wire from the right sternoclavicular joint: a case report

Background

Migration of wires and pins within the heart is an uncommon complication. Intracardic migration of Kirschner wire can cause several complications.

Case presentation

A 55-year-old male patient was admitted to the emergency service with dyspnea, stabbing chest pain. The patient’s medical history showed that he had undergone a fixation operation using Kirschner wire and plate for treatment of the right sternoclavicular joint dislocation about 5 months prior. Chest computerized tomography revealed a metallic foreign body locating in the pericardium between the aorta and the right ventricle. There were not any serious complications occurred before operation due to the timely detection of potential risks. Removal of the wire was performed via median sternotomy under general anesthesia without cardiopulmonary bypass. The symptoms of dyspnea and chest pain were relieved after surgery, and the patient recovered without any complications.

Conclusion

The Kirschner wire should be used judiciously in amphiarthrosis in orthopedic surgery for the risk of breakage and migration. The possibility of intracardiac migration of wire should be considered when chest symptoms presenting after surgery with the Kirschner wire. Migrated wires must be removed immediately to prevent serious complications. Regular follow-up and early removal of fixation wires are recommended to prevent migration of wires.