Summary
Objective: To report a novel method of treating femoro-patellar instability in association with
severe femoro-patellar osteoarthritis, by substituting the femoral trochlear with
a patellar groove replacement prosthesis.
Study design: Retrospective case series.
Methods: Preoperative lameness was scored from 0–4, and radiographic studies including standard
positions for patellar luxation were obtained for evidence of malalignment and femoro-patellar
osteoarthritis. Cases with or without previous surgeries were included. The size of
trochlear implant was determined by transparent templates and confirmed intra-operatively
with trials. Radiographic images, together with clinical examinations, were reviewed
immediately and at three months postoperatively and at longer term when available.
Results: Thirty-five cases of patellar luxation ranging from grades II to IV were included.
Eleven of these cases had prior surgical interventions which failed to stabilize the
patella. Fourteen dogs required additional surgical procedures in conjunction with
patellar groove replacement. Complications occurred in six patients, of which three
required revision. Complete resolution of subjectively- assessed lameness was evident
in 24/35 cases by the third month and in another seven of 35 patients on the longer
term re-evaluations.
Clinical significance: Use of a patellar groove replacement prosthesis has the potential to decrease the
lameness associated with severe femoro-patellar arthritis, to improve patellar stability,
and to correct the alignment of the extensor mechanism.
Keywords
Dog - patellar luxation - partial stifle joint prosthesis
