Issue: October 2016
October 07, 2016
2 min read

Longer return-to-running time found with higher grade femoral neck stress fractures

Patients with lower BMI tended to have higher severity fracture and a longer return-to-running time.

Issue: October 2016
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Patients with grade 2 to 4 femoral neck stress fractures experienced longer return-to-running time compared with grade 1 injuries, according to a study.

“Grade 1 injuries, as graded by the Arendt stress fracture grading scale, returned to running more quickly, with an average return-to-running time of 7.4 weeks when compared to higher grade femoral neck stress fractures, with an average return-to-running time of 17.5 weeks for grade 4 injuries,” Lindsay N. Ramey, MD, sports medicine fellow at the Rehabilitation Institute of Chicago, told Orthopedics Today.

Femoral neck stress fractures

Ramey and her colleagues reviewed charts of 24 patients (85.2% women) with 27 compression-sided femoral neck stress fractures managed nonoperatively for patient demographics and return-to-running time. Researchers graded images from one to using the Arendt stress fracture severity scale.

Results showed patients with grade 1 femoral neck stress fractures had a mean return-to-running time of approximately 7.4 weeks compared to approximately 13.8 weeks for grade 2, 14.7 weeks for grade 3 and 17.5 weeks for grade 4 fractures. Researchers found a statistically significant effect of fracture grade on return-to-running time through survival analysis. According to the Cox model, return-to-running time was statistically different between grade 1 and all other grades. Hazard ratio was significant.

“We also assessed specific patient characteristics to identify other variables associated with return-to-running time. We found people with lower BMI tended to have fractures of increasing severity and independently had a longer return-to-running time,” Ramey said. “Runners with low BMI should be counseled that they may be at an increased risk for higher grade fractures and longer return-to-running time.”

Return-to-running time was not significantly affected by age or bone mineral density. Cox analysis and hazard ratio remained significant after adjusting for age and bone mineral density.

Low sample size

Due to the low patient sample size, Ramey noted a high risk for type 2 error. For this reason, associations between patient characteristics, femoral neck fractures and return-to-running time should not be ruled out based on this study, she added.

“Moving forward, we hope to assess a larger sample in a multicenter, prospective trial to confirm the associations found in this study. We would also like to assess additional patient variables that may contribute to return-to-running time, including vitamin D level, symptom duration and pain severity to better predict recovery time and identify modifiable risk factors for high-grade injuries requiring longer time out of running,” Ramey said. – by Casey Tingle

Disclosure: Ramey reports no relevant financial disclosures.