Risk of septic knee following retrograde intramedullary nailing of open and closed femur fractures

All patients who received a retrograde femoral nail for femur fracture between September 1996 and November 2006 at a Level 1 trauma center were retrospectively reviewed. This yielded 143 closed fractures, 38 open fractures and 4 closed fractures with an ipsilateral traumatic knee arthrotomy. Patient follow-up records were reviewed for documentation of septic knee via operative notes, wound culture or knee aspirate data, or the administration of antibiotics for suspected septic knee.No evidence of septic knee was found in the 185 fractures examined in the dataset. Utilizing the Wilson confidence interval, the rate of septic knee based on our population was no greater than 2%, with that of the open fracture group alone being 9%.Based on these results and review of the literature, the risk of septic knee in retrograde femoral nailing of both open and closed femoral shaft fractures appears low but potentially not insignificant.There was no outside source of funding from either industry or other organization for this study.Fractures of the femur are a common injury encountered by orthopaedic surgeons. Intramedullary nailing has become the gold standard for treatment of shaft fractures and has been routinely employed since the 1970's[1-4]. Traditionally, femoral nails have been inserted in an antegrade fashion with a start point at the piriformis fossa or the greater trochanter. Retrograde nails utilizing an intra-articular insertion point at the knee with a retrograde trajectory for femoral nailing has been described [5] and has gained great popularity in recent years. As the indications for retrograde nailing continue to evolve [6-15], several publications have reported comparable outcomes following retrograde or antegrade femoral nailing. The retrograde technique confers potentially unique complications as compared with the antegrade technique. One area of concern involves infection of the knee joint [8,9,16]. There are many proposed mechanisms for development of a sep