Session I - Hip Fractures

Weightbearing after Hip Fracture: A Prospective Computerized Gait Analysis Comparing the Effects of Surgical Treatment

Kenneth J. Koval, MD, Debbie Sala, MS, PT, Fred J. Kummer, PhD , Joseph D. Zuckerman, MD

Hospital for Joint Diseases, New York, NY

Introduction: The optimal weightbearing status after hip fracture surgery remains controversial. Restricted weightbearing can delay the elderly hip fracture patient's functional recovery and return to independent living, yet some surgeons hesitate to allow immediate unrestricted weightbearing. It has been the practice at our hospital to allow all hip fracture patients to bear weight as tolerated after surgery; we believe that patients will voluntarily limit weightbearing based upon the degree of their discomfort and /or apprehension. The purpose of this study was to quantify weightbearing in the early postoperative period by studying hip fracture patients who were allowed to weight-bear as tolerated and to examine the relationship between weightbearing and treatment technique.

Methods: All surgically treated hip fracture patients admitted to our hospital were considered for inclusion in this IRB-approved study. Exclusion criteria included dementia, nonambulatory status, and history of contralateral hip fracture or ipsilateral lower extremity fracture precluding unrestricted weightbearing. All patients followed a similar postoperative protocol, consisting of patient mobilization out of bed post-op day 1 and full unrestricted weightbearing using assistive devices as needed. Computerized gait analysis was made at 1, 2, 3, 6, and 12 weeks postoperatively using the F-Scan System (Tekscan, Boston, MA), which uses a 900-element-array flat transducer inserted in the patient's footwear to measure plantar vertical loads. From the gait recording, five representative steps per (patient) foot were used to calculate average load, maximum load, and time per step and to determine the type of gait (e.g., heel-to-toe, flat) for the operative and contralateral sides. Statistical analysis was performed by analysis of variance, with p <.05 considered significant.

Results: Sixty patients were enrolled in the study; average patient age was 77 years. The fracture types and treatment categories were:

Nondisplaced FN-ORIF (7) Displaced EN-ORIF (10)

Displaced FN-HA (18) Stable IT-ORIF (15)

Unstable IT-ORIF (10)

Stable FN and stable IT fractures treated with ORIF and those who had a prosthetic replacement had similar weightbearing loads (65% of the contralateral side at 1 week, increasing to 95% at 12 weeks). Displaced FN fractures treated with ORIF and unstable IT fractures demonstrated the least weightbearing (40% at 1 week, 78% at 12 weeks). This difference between these two groups was statistically significant. The average loads for all groups increased as a function of time (60% at 1 week, 87% at 12 weeks). Maximum loads showed similar behavior. There was no identifiable relationship between the amount of weightbearing and type of gait. Weightbearing was inversely correlated with total gait cycle time, although the time spent on both sides was similar in all cases. One patient experienced loss of fixation; this patient demonstrated decreasing weightbearing in the two measurement periods prior to failure.

Discussion: This study supports the use of unrestricted weightbearing after hip fracture surgery. Patients with displaced femoral neck and unstable intertrochanteric fractures placed partial weight on the injured extremity in the early postoperative period despite instructions to weightbear as tolerated. As expected, patients with nondisplaced femoral neck and stable intertrochanteric fractures and those who had a prosthetic replacement bore more weight on the injured extremity than those with unstable fracture patterns. In all patients who had uneventful healing, the amount of weight placed on the injured extremity increased over time.

Conclusion: Hip fracture patients place partial weight on the injured extremity in the early postoperative period when allowed weightbearing as tolerated ambulation. These patients can be allowed unrestricted weightbearing after hip fracture surgery. In this series of patients, this approach did not appear to result in an increased rate of either fixation failure or healing complications.