Influence of nail prominence and insertion point on anterior knee pain after tibial intramedullary nailing.

Chronic anterior knee pain is the most common complication after tibial nail insertion. Its etiology remains unknown, and multifactorial sources have been suggested. The authors believe that nail prominence and the insertion point of the nail are important in the development of anterior knee pain. The purpose of this retrospective study was to evaluate the roles of the insertion point and nail prominence in anterior knee pain after tibial intramedullary nailing using a transtendinous approach and a common nail type. A total of 108 patients with tibial shaft fractures underwent reamed intramedullary nailing using a transtendinous approach between 2006 and 2009. Mean follow-up was 26.8±5.0 months. A visual analog scale (0-100) was used to estimate anterior knee pain severity while patients performed 7 activities retrospectively. Radiographic assessments, including nail prominence and insertion point, were performed. Sixty (55.6%) patients experienced knee pain (group P) and 48 (44.4%) did not (group N). Significant differences were not found between the groups with respect to demographics, nail diameters, or fracture classifications. Less superior and more anterior nail prominences in radiographic assessments were significantly associated with anterior knee pain. When the insertion point was over the bottom half of the anterior cortex, the influence of anterior nail prominence was more obvious. Nail removal resulted in diminished pain during the 7 assessed activities. Nail insertion should be over the bottom half of the anterior cortex, with minimal anterior nail prominence. If anterior knee pain occurs, removal of the nail should be considered.