Fig. 1 Radiographs of a 33-year-old male who sustained a gunshot wound to the right femur. He was allowed immediate weight bearing as tolerated after trochanteric-start site reconstruction nailing and was discharged home 2 days after surgery. (A) Injury; (B) 6 weeks postoperative; (C) union at 10 months.
Courtesy of Hrayr Basmajian, MD


Published 11/1/2015
Maureen Leahy

Study Finds Benefit to Early Weight Bearing

WBAT following IM fixation of subtrochanteric femur fractures decreases hospital LOS

Study data presented at the Orthopaedic Trauma Association annual meeting indicate that immediate weight bearing as tolerated (WBAT) following intramedullary (IM) fixation of subtrochanteric femur fractures decreases hospital length of stay (LOS) and does not appear to increase the risk of implant failure or nonunion.

The benefits of early weight bearing and mobilization in trauma patients and the safety of statically locked IM nails in highly comminuted femoral shaft fractures are clearly documented. Data supporting immediate postoperative weight bearing after IM fixation of subtrochanteric femur fractures, however, are rare, according to Brian P. Cunningham, MD.

"Subtrochanteric femur fractures have historically been very difficult to treat. They are technically challenging with a high complication rate and most surgeons are very conservative with advancing weight bearing," he said. "We hypothesized that when these fractures were treated with modern cephalomedullary nails, immediate weight bearing would decrease hospital LOS."

Retrospective cohort analysis
The researchers conducted a retrospective cohort study of 69 skeletally mature patients (mean age = 55.7 years) with subtrochanteric femur fractures who had been treated at two Level-1 trauma centers between August 2009 and November 2015. The predominant implant used was the cephalo­medullary nail (83 percent). The following exclusion criteria were applied:

  • initial Glasgow Coma Scale below 8
  • orthopaedic injury affecting weight bearing
  • thoracic or abdominal injury requiring surgery
  • periprosthetic fracture
  • diphosphonate-related atypical subtrochanteric femoral fracture

Among the 69 patients, 35 patients (mean age = 36.5 years) had sustained high-energy injuries; 34 patients (mean age = 73.4 years) had sustained low-energy falls. Surgeon preference dictated the use of the WBAT postoperative protocol. Additional demographics evaluated included sex, body mass index, implant type, implant size, degree of comminution, and fracture type. The study's primary outcome was hospital LOS. 

Study findings
Overall, WBAT patients had a decreased hospital LOS compared to non–weight-bearing (NWB) patients (4.5 days vs. 5.9 days; P = 0.01). Although patients in the high-energy group had an increased overall LOS compared to those in the low-energy group, subgroup analysis of patients in the high-energy group with highly comminuted fracture patterns revealed a decreased LOS when WBAT was allowed.

In addition, the researchers found that patient age and body mass index had no confounding correlation with LOS, and that no statistical differences existed in union rates or implant failures between the WBAT and NWB groups.

"The most significant result of the study was that everyone benefited. Not only did older patients with low-energy fractures benefit from early immediate weight bearing, but so did young high-energy fracture patients (Fig. 1)," Dr. Cunningham said. "Although the sample size was relatively small and underpowered to evaluate failure rate, our study did show a very clear benefit of early WBAT. This study also led to a large collaborative project that will have the requisite power to examine if a difference in failure rate or reparation exists between the two groups."

Dr. Cunningham's coauthors of "Immediate Weight Bearing as Tolerated Has Improved Outcomes Compared to Non-Weight Bearing after Intramedullary Fixation for Subtrochanteric Fractures" are Justin Roberts, MD; Saif Zaman, MD; Gilbert Ortega, MD, MPH; Anthony S. Rhorer, MD; Hrayr Basmajian, MD; Ryan McLemore, PhD; and Brian Miller, MD. The authors' disclosure information can be accessed at

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at

Bottom Line

  • Subtrochanteric femur fractures have a high complication rate, and postoperative protocols with respect to weight bearing are inconsistent.
  • In this small study, immediate WBAT following IM fixation of subtrochanteric femur fractures resulted in shorter hospital stays compared to NWB.
  • Immediate WBAT also did not appear to increase the risk of implant failure or nonunion.
  • High-energy comminuted subtrochanteric fractures may also benefit from early WBAT following IM nailing.

Additional Information:
Information Statement