Predictors of Patient Reported Pain After Lower Extremity Nonunion Surgery: The Nicotine Effect

Nonunion of long bone fractures is a serious complication for many patients leading to considerable morbidity. The purpose of this study is to elucidate factors affecting continued pain following long bone nonunion surgery and offer better pain control advice to patients.

Patients presenting to our institutions for operative treatment of long bone fracture nonunion were enrolled in a prospective data registry. Enrolled patients were followed at regular intervals for 12 months using the Short Musculoskeletal Function Assessment (SMFA), visual analog scale (VAS), physical examination, and radiographic examination. The registry was reviewed to identify patients with a tibial or femoral nonunion that went on to union with complete follow up. Univariate analyses were conducted to identify patient characteristics associated with postoperative pain. Identified patient factors with univariate p-values <0.1 were included in multivariate linear regression models in order to identify risk factors for pain 3 months, 6 months, and 12 months after nonunion surgery.

Ninety-one patients with tibial or femoral nonunion who went on to union and had complete follow-up were identified. A Friedman test revealed mean pain score decreased significantly by 3 months postoperatively (p<0.0005). Univariate analyses demonstrated age (p=0.016), days from injury to nonunion surgery at our institution (p=0.067), smoking status (p<0.0005), wound status at time of injury (p=0.085), anesthesia (p=0.045), and nonunion location in the bone (p=0.047) were associated with postoperative pain in at least one time point postoperatively. These were included in multivariate models that revealed nonunion location (p=0.035) was predictive of pain 3 months postoperatively, smoking status was predictive of pain 3 months (p=0.012) and 6 months (p<0.0005) postoperatively, and days from injury to nonunion surgery at our institution was predictive of pain 6 months (p=0.024) and 12 months (p=0.004) postoperatively.

Healed patients have improved pain levels after lower extremity nonunion surgery. Orthopedic surgeons should stress smoking cessation programs and minimize delay to nonunion surgery, in order to maximize pain relief in this patient cohort.