Determination of reference values and frequency of occurrence of patella alta in German shepherd dogs: a retrospective study

Abstract

BackgroundPatella alta and patella baja are important conditions underlying a predisposition to many joint diseases, including patellar luxation and patellar chondromalacia of the articular cartilage. The frequencies of patella alta and patella baja have not yet been determined. The objectives of this study were to determine the frequency of patella alta and to determine reference values to the position of the vertical patella according to two modified techniques of the Insall–Salvati method in a group of 65 German shepherd dogs (115 stifle joints).ResultsThe upper limits of reference values for the normal vertical position of the patella were 1.79 and 2.13, depending on the method of measurement. A high prevalence of patella alta was observed in the group of German shepherd dogs. A correlation was demonstrated between the classification of dogs’ joints in the patella alta group and the multiplied risk of canine hip dysplasia (CHD) through the estimation of odds ratios.ConclusionsDogs with patella alta were healthy dogs that did not exhibit orthopaedic problems in the stifle joints. The results revealed that the risk of CHD is twice as high in dogs with higher patellar ligament length to patella length ratio.

Radiographic evaluation of patellar tendon length following corrective surgical procedures for medial patellar luxation in dogs

“…Other investigators have also detected a correlation between body weight and risk of recurrence of luxation following MPL corrective procedures [9,11]. The average body weight of dogs included in our investigation was lower than those reported in other studies investigating PLL:PL [4,12]. This is due to the fact that the aforementioned studies only included populations of large breed dogs, while our study population included both large and small breed dogs.…”

“…Other investigators have demonstrated shortening of patellar tendon length following tibial plateau leveling osteotomy procedures in dogs [ 15 ]. Although patella alta has previously been proposed as predisposing factor to post-operative recurrence of luxation, other studies have demonstrated this condition in healthy dogs without evidence of orthopedic disease [ 12 , 16 ]. These factors in addition to other underlying soft tissue and skeletal abnormalities may all contribute to changes in patellar tendon length.…”

“…Because the measurement was a ratio, calibration of the images was not necessary and thus was not performed. The angle between the femur and tibia was not measured, as previous studies have demonstrated no association between the degree of stifle flexion and two methods of calculating PTL:PL [12]. All measurements were made by one of the investigators (KD).…”

Surgical Treatments for Canine Anterior Cruciate Ligament Rupture: Assessing Functional Recovery Through Multibody Comparative Analysis

“…The tibia together with the fibula were modeled as a single body (i.e., tibiofibular joints are considered as fixed joints). The patella was represented as an ellipsoid with its major length based on values found in the literature (Łojszczyk-Szczepaniak et al, 2017) and its other two perpendicular dimensions were chosen to make it congruent to the femoral groove. Given the patellar length, its vertical position with respect to other bones, on the sagittal plane, was chosen based on the mean ratio of the patellar ligament length to the patellar length itself, which is equal to 1.45 (Johnson et al, 2006).…”

Measurement of Patellar Proximodistal Positioning with Limited Joint-Angle Sensitivity

“…The study population was small, and consisted of a large breed not typically associated with patellar luxation: variations due to patient size, breed and conformation have been noted previously. 6,17,18 The significant effect of sex during canine screening represents a size-related type I error related to the presence of relatively large male dogs, as this effect was not confirmed in the larger evaluation, in which body mass was smaller. Further studies, covering a range of breeds, are necessary to establish confidence in index A as a tool for preoperative and postoperative assessment of patellar luxation patients.…”