PURPOSE:
The purpose of this OTA approved pilot study was to compare the clinical and functional outcomes of the knee joint after infra - versus supra patellar tibial nail insertion DESIGN:: Prospective, randomized, OTA sponsored, Level I study.

SETTING:
Level I trauma center METHODS:: After IRB approval, skeletally mature patients with OTA 42 tibial shaft fractures were randomized into either an infra-patellar (IP) or suprapatellar (SP) nail insertion group after informed consent was obtained. The SP also underwent a pre- and post-nail insertion patella-femoral (PF) joint arthroscopy. Patients underwent follow-up (6 weeks, 3-, 6-, & 12-months) with standard radiographs, as well as visual analog score (VAS) and pain diagram documentation. At the 6- and 12-month visits, knee function questionnaires (Lysholm knee scale and SF-36) were completed. MRI of the affected knee was obtained at 12 months. Ten patients in each group was required for a power analysis for the anticipated larger RCT, but enrollment in each arm was not limited, due to known problems with patient follow-up over a 12 month period.

RESULTS:
A total of 41 patients/fractures were enrolled in this study. Of those, only 25 patients/fractures (14 IP, 11 SP) fully complied with, and completed 12 months follow-up. 6/11 SP presented with articular changes (chondromalacia) in the PF joint during the pre-insertion arthroscopy. Three patients displayed a change in the articular cartilage based on post nail insertion arthroscopy. At 12 months, all fractures in both groups had proceeded to union. There were no differences between the affected and unaffected knee with respect to range of motion. Functional VAS and Lysholm knee scores showed no significant differences between groups (p>0.05). The SF-36v2 comparison also revealed no significant differences in the overall score, all 4 mental components, and 3/4 physical components (p>0.05). The bodily pain component score was superior in the SP group (45 vs. 36, p=0.035). All 11 SP patients obtained MRIs at 1-year. Five of these patients had evidence of chondromalacia on MRI. These findings did not correlate with either the pre or post nail insertion arthroscopy. Importantly no patient in the SP group with post nail insertion arthroscopic changes had PF joint pain at one year.

CONCLUSION:
Overall, there appeared to be no significant differences in pain, disability, or knee range of motion between these two tibial intramedullary nail insertion techniques after 12 months follow-up. Based on this pilot study data, larger prospective trial with long-term follow-up is warranted.

LEVEL OF EVIDENCE:
Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.