Vet Comp Orthop Traumatol 2015; 28(04): 270-273
DOI: 10.3415/VCOT-15-02-0028
Original Research
Schattauer GmbH

Proximo-distal patellar position in three small dog breeds with medial patellar luxation

C. Wangdee
1   Department of Veterinary Surgery, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
,
L. F. H. Theyse
2   Department of Clinical Sciences and Services, The Royal Veterinary College, Hatfield, UK
,
H. A. W. Hazewinkel
3   Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
› Author Affiliations
Further Information

Publication History

Received:06 February 2015

Accepted:24 April 2015

Publication Date:
28 December 2017 (online)

Summary

Introduction: Medial patellar luxation is thought to be associated with a high proximal position of the patella in the trochlear groove.

Objective: To determine whether the ratio of patellar ligament length and patellar length (L:P) is influenced by the stifle angle (75°, 96°, 113°, 130°, and 148°) in small dog breeds and to compare the L:P ratio in dogs of three small dog breeds with and without medial patellar luxation.

Methods: A mediolateral radiograph of the stifle joint was used to measure the L:P ratio in the stifle joints of dogs of three small breeds with and without medial patellar luxation. The L:P ratio was evaluated at five stifle angles (75°, 96°, 113°, 130°, and 148°) in 14 cadavers (26 stifle joints) of small dog breeds in order to identify the best stifle angle to measure the L:P ratio. Then the mean ± SD L:P ratio was calculated for normal stifles and stifles with medial patellar luxation grades 1, 2, and 3 in 194 Pomeranians, 74 Chihuahuas, and 41 Toy or Standard Poodles.

Results: The L:P ratio was the same for all five stifle angles in the cadavers (p = 0.195). It was also not significantly different in the three breeds (p = 0.135), in normal and medial patellar luxation-affected stifles overall (p = 0.354), and in normal and medial patellar luxation-affected joints within each breed (p = 0.19).

Clinical significance: We conclude that a proximo-distal patellar position is not associated with medial patellar luxation in Pomeranians, Chihuahuas, and Toy or Standard Poodles. Thus a longer patellar ligament length does not play a role in the pathophysiology of medial patellar luxation in these small dog breeds.

 
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