title: Dynamic hip screw for the treatment of femoral neck fractures: a prospective study with 96 patients.
abstract: Objectives. To study the correlation between avascular necrosis and the demographics, time elapsed from fracture to surgery, quality of reduction, Garden classification, and the position of the screw following use of the dynamic hip screw (DHS) in the treatment of subcapital neck fractures. Methods. A prospective study of 96 patients with subcapital neck fractures was carried out in a faculty hospital. Patients underwent surgery with closed reduction and internal fixation with DHS. Results. There were 58% male and 42% female patients, with a mean age of 53 years (+/-14). In terms of Garden classification, 60% were Garden IV, 26% were Garden III, and 14% were Garden II. Nonunion was observed in three cases (3%) and was treated with valgus intertrochanteric osteotomy, in all cases leading to successful healing. Avascular necrosis was observed in 16% of patients. The positioning of the screw into the femoral head showed a significant correlation with necrosis. Conclusions. The incidence of necrosis in patients under the age of 50 years is twice as high as that in older patients. Displacement is a predictive factor regarding osteonecrosis and is associated with a high and anterior position of the screw in the femoral head. Level II of evidence.
  
  
  METHODS
  therapeutic study.
authors: Orthopaedics and Traumatology, Federal University of Health Sciences of Porto Alegre and Santa Casa de Misericordia of Porto Alegre, Rua Leopoldo Bier, 825/cj 403, 90620-100 Porto Alegre, RS, Brazil.
authors: Carlos Roberto
authors: CR
authors: Schwartsmann
authors: Department of Orthopaedics and Traumatology/Pediatrics, Santa Casa de Misericordia of Porto Alegre, Avenida Independência, 155, 90035-074 Porto Alegre, RS, Brazil.
authors: Lucas Senger
authors: LS
authors: Jacobus
authors: Department of Orthopaedics and Traumatology/Hip Surgery, Santa Clara Hospital, Santa Casa de Misericordia of Porto Alegre, Reception 8, Rua Professor Annes Dias, 135, 90020-000 Porto Alegre, RS, Brazil.
authors: Leandro de Freitas
authors: Lde F
authors: Spinelli
authors: Department of Orthopaedics and Traumatology/Hip Surgery, Santa Clara Hospital, Santa Casa de Misericordia of Porto Alegre, Reception 8, Rua Professor Annes Dias, 135, 90020-000 Porto Alegre, RS, Brazil.
authors: Leonardo Carbonera
authors: LC
authors: Boschin
authors: Department of Orthopaedics and Traumatology/Hip Surgery, Santa Clara Hospital, Santa Casa de Misericordia of Porto Alegre, Reception 8, Rua Professor Annes Dias, 135, 90020-000 Porto Alegre, RS, Brazil.
authors: Ramiro Zilles
authors: RZ
authors: Gonçalves
authors: Department of Orthopaedics and Traumatology/Hip Surgery, Santa Clara Hospital, Santa Casa de Misericordia of Porto Alegre, Reception 8, Rua Professor Annes Dias, 135, 90020-000 Porto Alegre, RS, Brazil.
authors: Anthony Kerbes
authors: AK
authors: Yépez
authors: Department of Physical Therapy, Santa Clara Hospital, Santa Casa de Misericordia of Porto Alegre, 2nd Floor, Rua Professor Annes Dias, 135, 90020-000 Porto Alegre, RS, Brazil.
authors: Rodrigo Py Gonçalves
authors: RP
authors: Barreto
authors: Department of Physical Therapy, Federal University of Health Sciences of Porto Alegre, Rua Sarmento Leite, 245, 90050-170 Porto Alegre, RS, Brazil.
authors: Marcelo Faria
authors: MF
authors: Silva