Fraturas da extremidade proximal do úmero: estudo comparativo entre dois métodos de fixação

Biomechanical comparison of screw-based zones of a spatial subchondral support plate for proximal humerus fractures

Stabilisation of proximal humerus fractures remains a surgical challenge. Spatial subchondral support (S3) plate promises to overcome common complications associated with conventional proximal humerus plates. This study compared the biomechanical performance of S3 plate with a fixed-angle hybrid blade (Equinoxe Fx) plate and a conventional fixed-angle locking plate (PHILOS). The effects of removal of different S3 plate screws on the humeral stability were also investigated. A total of 20 synthetic left humeri were osteotomised transversely at the surgical neck to simulate a two-part fracture and were each treated with an S3 plate. Head screws were divided into three zones based on their distance from the fracture site. Specimens were divided into four equal groups where one group acted as a control with all screws and three groups had one of the screw zones missing. With humeral head fixed, humeral shaft was first displaced 5 mm in extension, flexion, valgus and varus direction (elastic testing) and then until 30 mm varus displacement (plastic testing). Load-displacement data were recorded to determine construct stiffness in elastic tests and assess specimens' varus stability under plastic testing. Removal of the screw nearest to the fracture site led to a 20.71% drop in mean elastic varus bending stiffness. Removal of the two inferomedial screw above it resulted in a larger drop. The proximal screw pair had the largest contribution to extension and flexion bending stiffness. Varus stiffness of S3 plate constructs was higher than PHILOS and Fx plate constructs. Stability of humeri treated with S3 plate depends on screws' number, orientation and location. Varus stiffness of S3 plate construct (10.54 N/mm) was higher than that of PHILOS (6.61 N/mm) and Fx (7.59 N/mm) plate constructs. We attribute this to S3 plates' thicker cross section, the 135° inclination of its screws with respect to the humeral shaft and the availability of pegs for subchondral support.

Posterior four-part fracture-dislocations of the proximal humerus: clinical and functional evaluation of osteosynthesis treatment

Objective

To evaluate patients diagnosed with posterior four-part fracture-dislocations of the proximal humerus, that were surgically treated with osteosynthesis, regarding their clinical and functional outcomes.

Methods

A prospective observational study of eight patients from the same hospital institution in the interior of São Paulo State (Brazil), through individual interviews using the UCLA, DASH, and Constant international scores. The active movements included in the scores plus the range of motion of the affected and non-affected limb were measured. The affected shoulder's radiographs were requested to verify bone conditions and the fixation of the osteosynthesis.

Results

The rating of eight patients by the international scores indicated that seven of the eight patients presented good clinical and functional evolution of the affected limb; this represents 87.5% of the evaluated individuals.

Conclusion

Surgical treatment with osteosynthesis performed during the acute period (<four weeks) leads to good results in most cases.

EPIDEMIOLOGICAL PROFILE OF PATIENTS WITH PROXIMAL HUMERUS FRACTURE TREATED AT HOSPITAL SÃO PAULO, BRAZIL

Objective: To analyze the epidemiological aspects of proximal humerus fractures and describe the profile of patients with proximal humerus fractures hospitalized and treated at Hospital São Paulo, between 2008 and 2013. Methods: Hospital records were retrospectively analyzed for surgically treated patients diagnosed with proximal humerus fracture. Age, gender, injury mechanism, length of hospital stay, performed treatment and associated diseases were considered. Results: From all patients studied, 52 were female at their sixth decade of life. As for the injury mechanism, fall from height was the main cause for women (88.46%) and for man it was motorcycle accidents (31.42%). Fixation with locked plate was the most frequently used treatment. Conclusion: Most patients were female in their fifth decade of life, injured mainly by fall from height. Fixation with locked plate was the most frequently used treatment and the patients were admitted for 7 days, on average. Level of Evidence II, Retrospective Study.

An overview of recently published medical papers in Brazilian scientific journals

A brief review intended as information to the readership of Clinics on papers recently published under various medical headings in Brazilian scientific journals recently indexed or about to be indexed in ISI-THOMSON Journal Citation Reports. Journals covered in this review are Acta Ortopédica Brasileira, Arquivos Brasileiros de Cardiologia, Jornal Brasileiro de Pneumologia, Revista Brasileira de Cirurgia Cardiovascular and Revista da Associação Médica Brasileira.