Garden type I fractures myth or reality? A prospective study comparing CT scans with X-ray findings in Garden type I femoral neck fractures

The Garden type I femoral neck fracture is defined as an incomplete fracture of the neck of the femur as seen on the antero-posterior (AP) radiograph of the injured hip. The diagnosis of incomplete femoral neck fractures has decreased in recent years with the development of improved radiographic imaging. We hypothesized that incomplete femoral neck fractures seen on radiographs are in fact complete fractures on computed tomography (CT). The study aims to test this hypothesis by comparing CT scan images to X-ray findings in patients diagnosed with Garden type I femoral neck fractures. From January 2008 to October 2010, our management of femoral neck fractures included a CT scan of the injured hip for all Garden type I fractures. CT findings were reported by a musculoskeletal radiologist. A classification of the fracture was performed by an orthopedic surgeon. Eight hundred and twenty five femoral neck fractures were admitted during the study period. Seventeen of these fractures (2.1%) were considered incomplete based on radiographic evaluation. In 17 cases (100%), the CT scan demonstrated a complete fracture extending through the medial cortex. Subsequently, all 17 fractures were fixed with standard cannulated screw technique on a fracture table. Secondary displacement occurred in one patient prior to fixation. All fractures healed well and no avascular necrosis was noted. In summary, our study shows that incomplete femoral neck fractures identified on X-rays are actually complete fractures based on CT scans. If confirmed by a larger study population, our findings can simplify the Garden classification by eliminating an inaccurate subcategory. The clinical implications are that Garden type I fractures should all likely be fixed with cannulated screws and with an effort to prevent displacement during treatment.

► The Garden type I femoral neck fracture is defined as incomplete on X-ray films.
► Seventeen of 825 fractures appeared incomplete based on radiographic evaluation.
► In 17 cases (100%), CT scan demonstrated a complete fracture.
► If confirmed by a larger study, the Garden classification will be simplified.
► Garden type I fractures should all likely be fixed with cannulated screws.