Fulkerson-based oblique novel technique (FONT) to treat concurrent cranial cruciate ligament disease and medial patellar luxation in the dog

Abstract

Objectives To assess the theoretical and morphometric effects of a novel oblique tibial tuberosity osteotomy technique designed to enable simultaneous advancement and lateralisation of the tibial tuberosity using a tibial tuberosity advancement cage for the surgical treatment of concurrent cranial cruciate ligament disease and medial patellar luxation in dogs. Study Design Computational modelling and ex vivo cadaveric study. Animals Fourteen pelvic limbs from mixed-breed dog cadavers (15.8 to 25.3 kg). Materials and Methods Theoretical calculations were performed to quantify tibial tuberosity displacement based on osteotomy angle and cage size using trigonometric principles. A 3D computer simulation was used to evaluate four osteotomy angles (0°, 25°, 30° and 35°). Oblique osteotomies targeting 30° were performed freehand on 14 cadaveric tibiae. Pre- and postoperative CT scans were used to measure the actual osteotomy angles achieved. Shapiro–Wilk and paired t-tests were used to assess data normality and statistical significance, respectively. Results The mean osteotomy angle achieved was 32.27° (SD ±3.4°), significantly different from the target angle of 30°. Lateralisation and advancement percentages for the tibial tuberosity were as follows: 0°: 0% lateralisation, 100% advancement; 25°: 42.3%, 90.7%; 30°: 50.0%, 86.7%; 35°: 57.3% and 82.0%, respectively. For all cage sizes (3, 6, 9 and 12 mm), lateral translation consistently exceeded the target value, whereas cranial translation was consistently lower than the target, showing statistically significant differences. Conclusion Simultaneous tibial tuberosity advancement and lateralisation could be achieved using an oblique osteotomy and standard tibial tuberosity advancement cage. However, freehand osteotomies demonstrate limited accuracy, suggesting that cutting guides may improve consistency. Clinical Significance This technique offers a novel approach to treat dogs with concurrent cranial cruciate ligament disease and medial patellar luxation, potentially simplifying surgical management through a single, oblique osteotomy.