Correlation between anthropometric determination of the retrograde fin nail length and intraoperative fin nail length measurement among adult patients with femur shaft fracture treated at Muhimbili Orthopedic Institute.

Abstract

ABSTRACT Background: The sign FIN nail is an intramedullary nail that is used in the treatment of femur shaft fractures. Preoperative measurements of accurate fin nail size for insertion are paramount as it saves operation time and prevents unnecessary unwrapping of nails during surgery. Anthropometric techniques used in preoperative determination of fin nail length include measuring the distance between the lateral knee joint line and greater trochanters most prominent portion, measurement of the most prominent part of greater trochanter and the superior pole of the patella and also measurement of the distance from the tip of the little finger to the olecranon. The gold standard for obtaining fin length is intraoperative fin nail estimation via use of marked reamer, nonetheless some literatures have shown that anthropometric preoperative determination of fin nail length is as well effective. This study aimed at assessing the accuracy of anthropometric determination of fin nail length among adult patients with femur shaft fracture treated at Muhimbili Orthopedic Institute (MOI). Objective: To determine the correlation of preoperative anthropometric determination of retrograde fin nail length and intraoperative fin nail length measurement among adult patients with femur shaft fracture treated at MOI. Materials and methods: A cross-sectional descriptive hospital-based study was carried out at Muhimbili orthopedic Institute from March 2023 to December 2023. A consecutive sampling technique was employed to obtain 44 patients after they had met inclusion criteria. These forty four patients with femur shaft fracture that were intended for flexible intramedullary nail (FIN IMN) insertion whether as an elective case or emergency case and satisfied the inclusion requirements and gave their consent to participate in the study. The preoperative measurement result as per the operating surgeon and two randomly selected residents was documented for each patient, the principal investigator also did the following anthropometric measurements: the distance between greater trochanter to “superior” pole of patella (GT-SP), greater trochanter to the lateral knee joint line (GT-LKJ) and olecranon to the tip of little finger (O-TF). Accuracy was determined by measuring intraoperative fin nil length using a marked reamer and compared to preoperative anthropometric fin nail length measurement. vi For categorical data, descriptive statistics like means and standard deviations was employed. These were entered into password-protected Excel spread sheet tables and then analyzed using Stata 14 software. The P value of <0.05 was considered statistically significant based on the two-sided t test. Result: A total of 44 patients were enrolled to the study. The mean age was 33, more than 60% were above 25 years and 86.36% were males. 81.82% were motor cycle accidents. The correlation between the intraoperative nail size and the pre operative measurements were significant and linear, with the highest correlation being between intraoperative nail size and olecranon to tip of little finger less 10cm. (spearman’s rho 0.87, p <0.01) Conclusion and recommendation: There was linear and positive correlation between the intraoperative nail size and all the pre operative measurements, and was also statistically significant. The study recommends the use of olecranon to tip of little finger less 10cm as first priority pre operative measurement, followed by olecranon to tip of little finger less 8cm as they were more accurate.