A CASE CONTROL STUDY FOR PREVALENCE AND SEVERITY OF ANTERIOR KNEE PAIN POST TIBIAL INTERLOCKING NAIL INSERTION

Intramedullary nailing of the tibia as a treatment of diaphyseal tibia fractures has been shown to produce excellent results with low rates of non union, mal union, joint stiffness, and infection when compared to alternative treatment. The prevalence of anterior knee pain following intramedullary tibial nail insertion has been reported as been between 10% to 86%, However, a recent meta-analysis of the literature estimated the incidence at 47.4%. Several studies have aimed to identify technical causes for the pain but there have been no comparisons made to the background population. The previous work has made no reference to or investigated any pre existing anterior knee pain in these patients. We hypothesized that the prevalence of anterior knee pain post tibial nailing is at the lower end of the published figures and is of low severity. We also hypothesized that pre-existing anterior knee pain is a significant contributory factor for the post tibial nailing anterior knee pain. Aims And Objectives : To compare the prevalence of anterior knee pain in the operated knee with the contralateral healthy knee using a VAS Score and to study functional impairment using a Functional Anterior Knee Pain Score of International Knee Society (Insall Modification - 1993). Material And Methods: Type of Study – Prospective cross-sectional Duration – June 2012 – January 2017. Minimum Sample Size- 50 patients. Study Methodology: All patients who had a tibial nail inserted at our institution (M.G.M Medical College and M.Y hospital, Indore) from June 2012 to July 2016. All patients in their follow up visit will be asked questions and questionnaire will be filled by the investigator relating to symptoms experienced in the knee of the injured limb and the knee of the contralateral normal side. The questionnaire included demographic data, occupation, Functional Anterior Knee Pain Score of Knee society (Insall Modification - 1993) maximum Knee and functional Score is 100 points, analogue pain score (0-10). The analogue scale used to divide patients into categories of mild or no pain (0-3), moderate pain (4-7), and severe pain (8- 10).Statistical Analysis will be carried out using the Unpaired t- test. Discussion: Comparison of vas score between the operated knee and contra lateral knee was done and unpaired “t” test was applied which was not statistically significant showing that mean pain score in both the knees was comparable which means that anterior knee pain is not necessarily associated with the tibial inter locking nail insertion. Whereas, in the previous study done by Cartwright-Terry et al studied that relative risk of anterior knee pain following tibial nailing is twofold compared to the contra lateral knee and to a comparative control population. The severity of any anterior knee pain in the uninjured limb is likely to correlate with post tibial nailing anterior knee pain. Insall results in relation to laterality of the operated knee were discussed which shows that 2.7% of the total population had poor results, 1.4% of the total population had fair results and 95.9% of the total population had excellent results and no association was found with the insall results and laterality of the operated knee. Comparison of vas score in relation to insall relation were done which showed that vas score in poor outcome was 9.0 in fair outcome it was 8.0 and an excellent outcome it was 2.01 which was statistically significant showing that vas score was highest in poor outcome and lowest in excellent outcome. One way anova test was applied which was statistically significant.Of the 33 knees in which anterior knee pain was present, contralateral knee pain was present in 30 and was absent in 3, while in all the 40 patients in whom the anterior knee pain was absent, it was absent too in contralateral knee. Conclusion: tibia interlocking nail insertion is not necessarily associated with the anterior knee pain, however, it may be responsible for the occurrence or increase in severity of anterior knee pain which may be already present in the knee when compared to the contra lateral knee which was taken as our control. Key words: Tibia Nail, Anterior Knee Pain, Functional Score, Pain Score