Preoperative Templating of Bone-Patellar Tendon-Bone Graft for Anterior Cruciate Ligament Reconstruction: A Morphometry-Based Graft Harvest Method.

BACKGROUND

Knowledge of anatomy and morphometry of the patella and patellar tendon is crucial for the selection of bone-patellar tendon-bone (BTB) graft for anterior cruciate ligament reconstruction. Graft tunnel mismatch in BTB graft especially in patients with patella alta or baja can result in compromised fixation for the bone-to-bone healing. This complication can be avoided by proper templating of graft using parameters measured from magnetic resonance imaging (MRI). The study aimed to derive morphometric data from MRI and predict the suitability of BTB graft preoperatively.

METHODS

MRI of 1,002 knees was chosen from database after applying the eligibility criteria, which included individuals in the age group of 18-50 years (both sexes) with the intact patella and patellar tendon. Individuals with pathologies of the knee joint and associated structures such as patellar fracture/dislocations, fractures of the distal femur and proximal tibia, and avulsion of the quadriceps tendon or patellar tendon were excluded. For analysis, 1.5 Tesla, proton density, and fat-suppressed sequences of sagittal and axial sections of T2-weighted MRI images were used.

RESULTS

Mean age of the 1,002 patients was 35.45 years and there were 290 women and 712 men. Respective measurements were as follows: patella length, width, and thickness, 40.3 mm, 40.2 mm, and 18.6 mm, respectively; patellar tendon length, width, and insertional thickness, 45.2 mm, 27.2 mm, and 5.7 mm, respectively; Insall-Salvati ratio, 1.13; overall graft length, 90.2 mm; and effective tendon length, 26.1 mm.

CONCLUSIONS

A simple MRI analysis can give us valuable inputs on BTB graft morphometry. The values can also help us with the near-perfect graft harvest. The intraoperative complication of graft tunnel mismatch can be avoided by predicting the overall graft length, effective tendon length, tibial tunnel length, and patellar position using the measured parameters on MRI.