LAUSR

OBJECTIVES To determine whether Hounsfield units (HU) measured on perioperative computed tomographic (CT) scans are associated with radiographic outcomes and reoperations after femoral neck fracture fixation. DESIGN Retrospective cohort study. SETTING Level I trauma center. PATIENTS One hundred fourteen patients age ≥18 years who presented to a Level I trauma center who underwent surgical fixation of intracapsular femoral neck fracture and had perioperative CT scans and adequate follow-up. INTERVENTION None. MAIN OUTCOME MEASUREMENTS Screw penetration, femoral neck shortening >5 mm, revision surgery. RESULTS Median follow-up was 23 months. HU measurement of the femoral head was significantly associated with screw penetration and femoral neck shortening but not revision surgery. Patients with middle femoral head HU measurements <146 had 17 times (95% CI: 4.32-78.9, P < 0.001) increased odds of screw penetration. Greater than 5 mm shortening was seen in Patients with HU <212.5 in the low head section by an odds ratio of 7.8 (95% CI: 2.15-33.0, P = 0.014). CONCLUSION Outcome differences regarding screw penetration and femoral neck shortening related to the HU or densities of femoral head and neck at the time of fracture are significant. These findings can help the clinician with developing a treatment plan for either arthroplasty or fixation of a femoral neck fracture based on objective bone quality measurements rather than relying on an arbitrary age recommendation. LEVEL OF EVIDENCE Diagnostic Level II. Development of diagnostic criteria.