Treatment of Patella Luxations in Dogs / Çatalkaya et al. ____________________________________________________________________________
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INTRODUCTION
Patellar luxation has an important place among hind leg lameness
in dogs (Canis lupus familiaris). It is possible to encounter both large
and small breed dogs [1, 2, 3, 4, 5, 6, 7]. The luxation may be medial
or lateral. While medial luxation is seen in small breed dogs, lateral
luxation is more common in large breed dogs [4, 6, 8, 9, 10]. The
incidence of medial patellar luxation in small breed dogs is 12 times
higher than in large breed dogs [4, 6, 9].
disorder in recent years [6, 7, 11, 12, 13], but it can also occur as a
result of a traumatic accident that causes rupture or stretching of
the joint capsule and fascia leading to femoropatellar instability [6,
11, 12]. Although the cause of patellar luxation is not fully understood,
malalignment in the quadriceps mechanism are important in the
development of this disease. Parts of the extensor mechanism of
the knee joint are the quadriceps muscle group, the patella, the
trochlear groove, the patellar ligament and the tibial tuberosity. Any
irregularity in this mechanism leads to some anatomical changes in
the distal femur and proximal tibia during the growth period, followed
by patellar instability [6, 12, 14, 15]. Additionally, causes such as distal
femoral varus or valgus, external or internal torsion of the distal femur,
proximal tibial varus or valgus, internal or external tibial torsion and
shallow trochlear sulcus structure also cause patellar luxation [6].
The diagnosis of patellar luxation is easy with clinical examination
as well as radiological examination [6, 15, 16, 17, 18]. Among the
surgical treatment methods, besides soft tissue techniques, bone
correction operations such as block recession sulcoplasty, wedge
recession sulcoplasty, and tibial tuberosity transposition have also
5, 6, 19]. Various complications can be encountered
in many of these operative techniques. These complications include
seroma, and osteoarthritis. Among the implant–related complications,
recurrence and fracture of the tibial crest are the most common
complications [6, 20]. Excess body weight has been associated
with a greater incidence of complications after operations of the
patellar luxation [20, 21]. In a study [4] conducted in dogs with patellar
luxation (medial luxation, lateral luxation, or both) weighing > 15 kg,
postoperative complications were reported in 29% of dogs, and it
was stated that there may be a relationship between body weight
and the development of complications. In another study [19] with
a similarly mixed population of 109 dogs with patellar luxation, the
prevalence of dogs with complications and major complications
and the frequency of relapses were greater among dogs weighing
> 20 kg. Lateral patella luxation is more common in larger dogs.
Therefore, dogs with a higher body weight may be at greater risk
for postoperative complications [21]. It has also been reported that
there may be a relationship between the simultaneous single session
in cases with bilateral patella luxation and the risk of complications
[6, 21]. It has been stated that this situation may cause excessive
stress on the implants and healing tissues in dogs undergoing bilateral
surgical repair in a single session, and recurrences may develop [21].
The purpose of this study was to report the history, clinical features
and outcome in dogs treated surgically for patellar luxation. In this
study postoperative complications and early and late outcomes were
evaluated.
MATERIALS AND METHODS
The clinical records of 32 dogs who applied to Dicle University
Veterinary Faculty Surgery Clinic between August 2019 and December
2022 with patellar luxation were analyzed. Gender, age, body weight,
breed, etiology (developmental or traumatic), unilateral or bilateral
luxation, duration of lameness, degree of luxation, direction of luxation
(medial or lateral), degree of lameness at presentation, presence of
concomitant cranial cruciate ligament rupture, treatment method
and complications were evaluated.
Grade of patellar luxation and lameness score
Degree of patellar luxation and lameness, Gibbons et al. [4] were
categorized as described. According to this;
TABLE I
The degrees of patellar luxation and lameness described by Gibbons et al. [4]
Degree of patellar
luxation
Grade 1
The patella was easily luxated with manual
pressure and returned to the femoral trochlea
when released
Grade 2
Patellar luxation occurred with rotation and
stie exion of the paw and returned to the
femoral trochlea
Grade 3
The patella was permanently luxated but could
be reduced with manual pressure
Grade 4
The patella can be permanently luxated and
manually reduced
Lameness scores
0 No lameness
1 Mild or intermittent lameness
2 Moderate lameness
3 Severe lameness
4 Non–weight bearing lameness
Examination and evaluation of the patient
Among the dogs diagnosed with patellar luxation according to
with grade 3 and grade 4 were included in the study.
Surgery
Routine preparations such as shaving asepsis and antisepsis of the
knee joint area of each dog with patellar luxation or patellar instability
included in the study were made and limited to sterile covers.
Dogs with patellar luxation, induction with 1–3 mg·kg
-1
IM xylazine HCl
(Rompun 2%, Bayer, Turkiye), 15–20 mg·kg
-1
IM ketamine HCl (Ketasol
(Sevorane 100%, AbbVie, Turkiye) was anesthetized.
parapetellar incision in all cases. The femoral trochlea, cranial cruciate
ligament, and menisci were evaluated. If there were partial injuries or
growths, they were removed. Femoral trochleoplasty was performed
3]. Tibial
tuberosity transpositions were performed manually using a bone