Objectives: To estimate the incidence of ligamentous knee injuries in patients with traumatic brain injury (TBI) involved in pedestrian versus motor vehicle collisions (PVMVC), to identify associated risk factors, and to compare rehabilitation outcomes and costs in TBI patients with and without ligamentous knee injury.
Design: Retrospective, case control.
Setting: An academic rehabilitation hospital with a large metropolitan referral base.
Patients: Twenty-three consecutive adolescent and adult subjects admitted for acute inpatient rehabilitation after a PVMVC from January 1, 1994, to January 1, 1996.
Results: Five subjects (22%) were found to have a ligamentous knee injury, one with bilateral injuries. Two of these six injuries were diagnosed only after presentation to the rehabilitation setting. The most common injury was an anterior cruciate ligament (ACL) disruption in 5 of 6 knees. A coupled ACL and medial collateral ligament injury was identified in 4 of 6 injured knees. The risk of ligamentous knee injury was most closely associated with the presence of a tibial plateau fracture (n=3) (chi2=12.420, p < .001). There was no statistical difference between groups with and without ligamentous knee injuries with respect to age, gender, inpatient acute or rehabilitation length of stay, admission, discharge, or change in motor Functional Independence Measure (FIM) interval measures, or rehabilitation costs. Four of the 5 patients with ligamentous knee injuries were successfully managed nonoperatively. A case illustrating longitudinal management is presented.
Conclusions: TBI and ligamentous knee injuries, in particular ACL injuries, are common comorbidities after PVMVC. Physicians must maintain a high index of suspicion for ligamentous knee injuries in this population, particularly when a tibial plateau fracture is present. TBI patients with and without ligamentous knee injuries can have comparable functional outcomes when the ligament injuries are identified and appropriately managed, without incurring undue cost or length of inpatient rehabilitation.