Is Preoperative Anthropometric Data Assessment Reliable Indicator for Estimating Femoral Tunnel Length in Anterior Cruciate Ligament Reconstruction?

Introduction: Correct length of the femoral tunnel is required for adequate length of graft inside the femoral canal. Length of femoral tunnel depends on mass, height, dimensions of lateral femoral condyle and amount of flexion of knee intraoperatively. Increasing weight and BMI affects the length of femoral canal since they affect positioning of limb in maximal knee flexion. Aim: To measure tunnel length in independent femoral tunnel drilling using the medial portal and to correlate the tunnel length with anthropometric data (height, weight, BMI of patient) and with width and depth of Lateral Femoral Condyle (LFC) based on MRI. Materials and Methods: The present prospective study including 40 patients were conducted. Participants were selected by a non-random convenience sampling methodology. Complete details of patients were collected by verbal communication with the patients and their attendees, clinical examination, baseline investigations, radiological investigations and surgical findings. Radiological investigations included preoperative assessment of LFC in MRI. Surgical findings were determined by measuring the femoral tunnel length after initial drilling through the medial portal using a depth gauge placed through the medial portal. SPSS version 17.0 was used for data analysis. Results: A total of 40 patients, 30 males and 10 females were included. Mean BMI was 24.22 kg/m2 with the range of 18 to 30. Mean width of LFC was 32.9 mm with range of 26.2 mm to 37.3 mm and depth of LFC was 58.79 with range of 50.7 mm to 66.2 mm. Mean femoral tunnel length was 38.4 mm with range from 32 mm to 44 mm. Conclusion: Average femoral tunnel length in Anterior Cruciate Ligament (ACL) reconstruction was 38.4 mm for assessed 40 patients. This correlated positively with height and weight of the patient. It also correlated positively with the width (p=0.027) and depth (p=0.029) of lateral femoral condyle.