Abstract
Objective The aim of this study was to identify the ideal anchor point for patellar anti-rotational
sutures for adjunctive stabilization of medial patellar luxation in both small and
large breed dogs.
Study Design Retrospective radiographic survey was performed on 110 stifles from 101 dogs. Radiographs
were grouped based on patient weight (≤15 kg; >15 kg) and diagnosis (medial patellar
luxation, cranial cruciate ligament rupture, and normal joints). Radiographic measurements
included: the proximal, middle, and distal points of the trochlear ridge, the caudal
aspect of Blumensaat's line (roof of the intercondylar notch), the centre of the lateral
fabella, as well as the “best-fit” centre of a circle overlying the trochlea. These
landmark coordinates were used to calculate radii for comparison, and for scaling
between joints.
Results Use of the fabellar centre resulted in larger radii (corrected p <0.001) than those from the best-fit circle centre for all but one combination of
patient group and trochlear end point locations. Using the best-fit circle centre,
radius variation was less marked than with the fabellar centre. Significant differences
in location for centres of the best-fit circle and fabella were seen across all patient
categories (Pillai's trace p <0.001).
Conclusion The fabella is unlikely to be the best choice for anchoring a patellar anti-rotational
suture. Use of the best-fit circle centre to place a suture anchor should be preferred
to maximise suture isometry during joint flexion and extension in large and small
breed dogs.
Keywords
dogs - stifle joint - patellar luxation - patellar anti-rotational suture - radiography
