Incidence, Etiology, and Risk Factors Associated with Foot Drop.

BACKGROUND: Injury to the neurological pathway that enables ankle dorsiflexion is likely to cause foot drop. This pathway includes the motor cortex; lumbosacral plexus; and the sciatic, tibial, and peroneal nerves. Nerve damage typically occurs due to compression, entrapment, traction, or direct trauma to the nerve due to several etiologies. However, there are limited reports on the incidence, etiology, and factors associated with foot drop.

METHODS: The authors reviewed their clinic's data from 1022 patients with foot drop from 2004 to present to determine the incidence, causes, and risk factors of foot drop. Microsoft Excel was used for descriptive statistical data analysis and graphing.

RESULTS: A total of 21 causes of foot drop were found. Of 1022 patients, 142 (13.9%) had foot drop after lumbosacral (LS) spine surgery, while 131 patients (12.8%) with LS spine complications who had not undergone surgery also reported foot drop. The LS spine complications and surgeries were influenced by age (median age, 63 and 55 years, respectively) and were marginally higher in male patients (54%). A total of 79 patients (7.8%) with foot drop had previously undergone hip replacement surgery. Older age (median age, 60 years) and female sex (85%) were risk factors for hip replacement surgery resulting in foot drop. In contrast, younger age and male sex were the risk factors for gunshot and stab wounds, injection drug use, drug or medication overdoses, and motor vehicle accidents resulting in foot drop.

CONCLUSIONS: Failed back surgery syndrome is the leading cause of foot drop after lumbosacral spine and hip replacement surgeries in both male and female older (median age, 60 years) patients. However, most (85%) of the foot drop patients in the present study who underwent hip replacement surgery were female patients. Sports and recreational activities, motor vehicle accidents, drug use, and violence are common causes of foot drop in younger male adults.