Impact of Weight-Bearing Status on Patient Gait During Fracture Recovery.

Optimizing weight-bearing can enhance fracture recovery, but measuring the response to weight-bearing protocols has been challenging to continuously and reliably study. We investigated whether smartphone-captured mobility metrics could detect functional differences in patients prescribed either early weight-bearing or delayed weight-bearing after lower extremity fractures. We conducted a cohort study, including adult patients with lower extremity fractures treated surgically, ≥6 months of follow-up, and an Apple iPhone for ≥1 year before injury. Patients with bilateral lower extremity fractures were excluded. Patients were classified as early weight-bearing or delayed weight-bearing. The primary outcome was step count, measured by the Apple iPhone Health application, within 12 weeks of injury. Secondary outcomes included walking speed and asymmetry, and an extended observation to 26 weeks postinjury. Between-group differences were estimated using linear mixed-effects models, controlling for preinjury mobility, age, sex, open fracture, and fracture location. We enrolled 74 patients (mean age, 46 SD, 19 years; 43% female), with 27 patients in the early weight-bearing group and 47 patients in the delayed weight-bearing group. Within 12 weeks of injury, early weight-bearing patients had markedly more daily steps than delayed weight-bearing patients (mean difference, 1,050 steps per day; 95% confidence interval CI, 373 to 1,727; P = 0.002). Secondary outcomes did not differ between the groups within 12 weeks of injury. However, by 26 weeks after injury, early weight-bearing patients had faster walking speeds (mean difference, 0.13 m/s; 95% CI, 0.04 to 0.22; P = 0.004) and less walking asymmetry (mean difference, -12.2%; 95% CI, -21.3% to -3.1%; P = 0.008) than delayed weight-bearing patients. Among patients with surgically treated lower extremity fractures, smartphone-collected step counts were higher in early versus delayed weight-bearing patients within 12 weeks of injury. These findings suggest that postoperative weight-bearing protocols affect patient mobility and can be measured continuously and remotely. Level III, Therapeutic.