Risks of concomitant trauma to the knee in lower limb long bone shaft fractures: A retrospective analysis from a prospective study population

Background: Numerous associated injuries (bony and/or soft tissue lesions) occur commonly in conjunction with fractures of the femoral shaft in young patients after high-energy injuries. Knee ligamentous injuries, historically called as the internal derangements of the knee or IDK, are mostly not visible in plain radiographs taken in the emergency and these injuries are likely to be overlooked by clinicians because first attention always goes to open wounds and radiologically visible injuries of the limb whenever a patient is received in a trauma unit. Materials and Methods: A total of 93 cases of lower limb long bone fractures were retrospectively analyzed from materials of a prospective study conducted on consecutive patients having high-velocity injuries to lower limb long bones with a view to confirm or rule out concomitant ipsilateral IDK in cases of femoral and tibial shaft fractures, that already employed a policy of focused clinical examination followed by arthroscopy of the ipsilateral knee, immediately after operative fracture fixation under the same anesthesia. The goal was to determine the incidence of concomitant internal derangement of the ipsilateral knee and to understand any value of adding arthroscopy to detect concomitant IDK in lower limb long bone fractures besides careful intraoperative examination to propose a recommendation thereof. Results: Concomitant knee injury was found in 14 femoral fractures and 1 tibial fracture. Fifteen out of 93 (16%) such cases had concomitant knee ligamentous or meniscal injures. A total of 13 anterior cruciate and 4 posterior cruciate tears, 11 collateral ligament tears, and 10 meniscal injuries were confirmed in these 15 knees. Femoral shaft fractures were associated with a high incidence of serious ligamentous, meniscal, and chondral injury. Twelve out of 41 femoral fractures had chondral injuries (contusion), especially of the patello-femoral articulation, identifiable during arthroscopy. Conclusion: One should have high index of suspicion about internal knee injuries and capsule-ligamentous injuries while dealing with femoral shaft fractures in particular. Arthroscopy of knee may safely enhance the diagnosis of simultaneous IDK. We propose that when MR imaging is not possible and when contraindication for arthroscopy does not exist, a careful clinical examination followed by arthroscopy of the knee may be considered a useful adjunct in femoral shaft fractures as it can readily confirm IDK by its ability to objectively look, probe, and distinguish fragile tissue from a normal one. Further study in larger number of subjects is needed to validate our findings