A Surgical Technique of Medial Patellar Luxation in Dogs

Liviu OANA

Abstract


Medial patellar luxation is a displacement of the patella from the trochlear sulcus, a common
cause of lameness in small-breed dogs, but also occurs in large-breed dogs . Without an adequate
treatment, medial displacement of the quadriceps muscle group, lateral torsion of the distal femur, a
lateral bowing of the distal one third of the femur, femoral epiphyseal dysplasia, rotational instability
of the stifle joint, or tibial deformity can occur. The grades of luxation (4 grades) and the best
therapeutic management can be established after the signalment, history, diagnostic imaging and
physical examination findings.
A 9-month-old female was presented for an intermittent weight-bearing lameness at left
hindleg. The leg holded in a flexed position at steps, patella luxated medially most of the time and
medial displacement of the quadriceps muscle group were the physical examination which included
the disease in grade 3 of medial patellar luxation .
Under general inhalatory anaesthesia, the method performed was trochlear resection. After a
lateral parapatellar arthrotomy, the technique consisted in removing of the articular cartilage and bone
from femoral trochlea with a rongeur. Medial and lateral trochlear ridges were made parallel to each
other and the base of the groove perpendicular to each trochlear ridge, so the new groove could
accommodate 50% of the height of patella. After trochlear resection, two layers of interrupted mayo
matress sutures (polyester 1-0) were done for a lateral capsular imbrication. No major intraoperative
and postoperative complications were noted. The local swelling of stifle decreased progressively in the
first days postoperative due to anti-inflamatory drugs (carprofen). A long-term sample protocol of
physical rehabilitation consisting in exercises (massage, passive range of motion, swimming,
criotherapy) was recommended. The normal function of the leg was observed after 12 weeks
postoperative.
Our case confirm that the trochlear resection is a simple surgical procedure which can reestablish
the normal alignment of the patellar complex mechanism, but it should only be performed
when a recession procedure or a lateral imbrication are impossible, because removing the articular
cartilage of the trochlea allows articulation of the patella on the rough cancellous surface, which
results in wearing of patellar articular cartilage in time.

Keywords


dog, patella, medial luxation.

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DOI: http://dx.doi.org/10.15835/buasvmcn-vm:67:2:6031


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