
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