Approximately 3,600 patients were operated at the Department of Orthopaedics at Stockholm Söder Hospital between January 1, 1999 and December 31, 2006 due to a trochanteric or subtrochanteric femoral fracture. All patients were registered in a clinical audit database. Until August 31, 2011, a total of 88 secondary hip arthroplasties had been performed after failure of the fracture treatment, and they were included in this study. All patients had undergone a primary operation with internal fixation of the fracture. No pathological fractures were included.
In addition to the audit data, all individual patient records were searched until August 31, 2011, or death, in order to find information about all reoperations. Finally, the Swedish personal identification number was used to perform a search in the national registry of the National Board of Health and Welfare to find patients who had been treated elsewhere in Sweden for a reoperation up to August 31, 2011. No such cases were found. The median follow-up time was 4.0 (0–11) years for all cases, and 7.9 (4.9–11) years for those who were still alive on August 31, 2011.
The mean (range) age at the primary operation was 83 (63–95) years for women (n = 76) and 81 (54–93) years for men (n = 12). The indication for the primary procedure was a trochanteric femoral fracture in 63 patients, and a subtrochanteric femoral fracture in 25 patients. The standard implant was a plate with a sliding hip screw (SHS) (Synthes, West Chester, PA) for stable 2-part trochanteric fractures. Unstable 3- to 4-part trochanteric fractures and subtrochanteric fractures were treated with a short Gamma nail (SGN), a long Gamma nail (LGN) (Stryker Howmedica, Kalamazoo, MI), or a Medoff sliding plate (Swemac, Linköping, Sweden) ().
Baseline data for all patients included (n = 88)
The median time between the primary IF operation and the secondary prosthesis operation was 5 (0.2–45) months. The most common indication for the secondary operation was a cutout of the sliding screw due to a fracture nonunion or femoral head necrosis (n = 59), followed by nonunion (n = 21), femoral head necrosis (n = 6), posttraumatic osteoarthritis (n = 1), and unacceptable implant position and fracture reduction (n = 1).
The prosthesis type used for the secondary operation was a THA in 63 patients and an HA in 25 patients. In the HA patients, the prosthesis used was a cemented Exeter HA with a unipolar Universal Head Replacement (n = 7) or a bipolar Bicentric Head with a 28-mm head (n = 18) (Stryker Howmedica, Kalamazoo, MI). Standard-length femoral stems were used in 47 of the hips, and long femoral stems in 41 (). An anterolateral surgical approach (Hardinge 1982
) with the patient in a lateral position was used in 53 patients, and a posterolateral surgical approach (Moore 1957
) with the patient in a lateral position was used in 35 patients. The total numbers of surgeons were 29 (23 consultants and 6 registrars).
Secondary prostheses used for all patients who were operated upon using a THA (n = 63)
The patients were mobilized on the day after surgery using crutches and allowed to bear weight as tolerated.
The study was approved by the Regional Ethics Committee in Stockholm June 15, 2011 (reference no. 2011/836-31/3).
Nominal variables were tested 2-sided by Fisher’s exact test. We used Cox regression to evaluate factors associated with reoperation risk. Primary fracture type, primary implant type, secondary prosthesis type, femoral stem length, and surgical approach were tested as independent factors in the model. First, crude associations for each factor were studied in univariable models. Secondly, a multivariable model with all independent factors was used to study the adjusted associations. The associations are presented as hazard ratios (HRs) with 95% confidence intervals (CIs). The results were considered significant at p-values < 0.05. The statistical software used was PASW Statistics 18 for Windows.