Background: Anterior knee pain is the most common complication after intramedullary tibial nailing. Often, the cause is multifactorial and individually different. Violation of the anterior intermeniscal ligament (AIL) during intramedullary tibial nailing might be a possible origin of postsurgical anterior knee pain. Both the importance and function of the AIL remain somewhat ambivalent, and even the figures quoted in the literature for its existence in the population vary drastically. Our aim was to verify the estimated frequency of the AIL in the literature by retrospectively analysing the data of MRI studies conducted at our hospital. In addition, we attempted to assess the potential risk of AIL violation during intramedullary tibial nailing, based on the spatial arrangement.
Methods: Two independent examiners analysed the images generated in 351 MRI studies conducted at our hospital between June 2013 and May 2014. All cases who did not reveal any previous knee-joint injury or osteoarthritis of the knee were allocated to group I. All other cases were included in group II. To estimate the potential risk of AIL injury during the nailing procedure, the distance between the AIL and the theoretical entry point for intramedullary nailing was measured.
Results: We identified the AIL on the images of nearly all patients (96.5%) in group I. In group II, the presence of the AIL was confirmed in only 51.4% of cases (p < 0.001). The average distance between the AIL and theoretical entry point for intramedullary tibial nailing was 10.1 mm (range 3.48-18.88 mm).
Conclusions: Because we were able to confirm the presence of the AIL in nearly all patients without a history of knee joint injuries or osteoarthrosis, we presume that the AIL may play a role in knee joint function. Violation of the AIL during intramedullary nailing appears likely due to the close position of the AIL in relation to the entry point for the inserted nail. As a result and due to its rich sensory innervation, a connection between AIL violation during tibial nailing and postoperative onset of anterior knee pain seems likely. To eliminate one risk factor of anterior knee pain development and in view of the unresolved issues of AIL function, violation of the ligament during any operative procedure should be avoided.
Keywords: Anterior intermeniscal ligament; Anterior knee pain; Safety zone; Tibial nailing.