Session IV - Femur

Outcomes of Acute Femoral Neck Fractures in Young Patients

Cory A. Collinge, MD; Scott Devinney, DO; Thomas DiPasquale, DO; Dolfi Herscovici, DO; Roy Sanders, MD, Florida Orthopaedic Institute, Tampa FL

Purpose: The reported rates of avascular necrosis, nonunion and failed treatment for femoral neck fractures in young adults vary widely. The effects of these sequelae remain unknown. The purpose of this study is to evaluate outcomes after acute femoral neck fractures in young adult patients and to assess factors that may have influenced these outcomes.

Methods: Sixty-eight patients between the ages of 15 and 49 years that were operatively treated for an acute fracture of the femoral neck between 1992 and 1998 were identified using our trauma registry. Forty-four patients were available for follow-up at a mean of 3.4 years (range 2.0-6.8 years). The mechanism of injury was high energy in 34 cases. Sixteen fractures were basicervical, 16 transcervical and 12 subcapital. Twenty fractures were classified as stable or non-displaced fractures and 24 were unstable displaced fractures. Twenty seven patients were treated with three 7.0 or 7.3 mm cannulated screws, 11 were treated with a 135 sliding hip screw, and 4 were treated with a sliding cephalomedullary nail. Patients underwent physical and radiographic examination and completed hip specific and SF-36 functional outcome instruments.

Results: The mean time to healing was 10.6 weeks (range 7-60). There were no wound infections. Two patients underwent revision surgery for failed fixation, 1 for malunion, and 1 for nonunion, all occurring in unstable fractures. Reduction was anatomic in 24, near anatomic in 16, while 4 were non-anatomic. Nineteen patients (43%) sustained identifiable avascular necrosis (1 Ficat stage I, 8 stage II, 6 stage III and 4 stage IV). Avascular necrosis (AVN) occurred in 10 transcervical fractures, 5 subcapital fractures and 4 basicervical fractures. Seventeen of the 19 patients with AVN (89%) suffered a displaced or unstable fracture, and 13 of these 19 occurred in unstable fractures that had undergone anatomic or near anatomic reduction and fixation within eight hours. Only one of 12 patients who had treatment of stable femoral neck fractures delayed greater than 24 hours developed stage III or IV AVN. Two of 4 patients with non-anatomic reductions developed stage IV AVN. The mean HHS of patients with AVN was 71.8 (range 27-97); however those with stages I or II AVN had a mean HHS of 89. Patients with no post-injury sequelae or lesser stages of AVN (I and II) had similar SF-36 profiles, while those with higher stages of AVN (III and IV) or nonunion had lower SF-36 scores.

Discussion: The literature describes femoral neck fractures in young adults as potentially devastating injuries. However, the reported rates of post-injury sequelae, including AVN, nonunion and failed treatment, vary widely and their effects on patient outcome remain unknown.

Conclusion: Most young adult patients presenting with a stable acute femoral neck fracture appear to have a satisfactory clinical outcome after reduction and surgical stabilization. Initial displacement of the fracture appears to correlate closely with the degree and severity of AVN, while the quality of the reduction appears to be less predictive, unless malreduced. While those patients experiencing sequelae such as severe AVN or nonunion had poor clinical results, lesser stages of AVN had little effect on outcome.