FREQUENCY AND DISTRIBUTION OF MEDIAL AND LATERAL PATELLAR LUXATION INDOGS - 124 CASES (1982-1992)

From the medical records of 124 dogs, patellar luxations were classifi ed as congenital or acquired, medial or lateral, and unilateral or bil ateral; were graded 1 to 4; and were subdivided according to size of d og. The 4 breed-size categories were based on guidelines from American Kennel club standards for adult height and weight. Findings from thes e records were compared with the results from dogs with other orthoped ic problems. A majority of dogs had congenital (91; 82%), as opposed t o acquired (17; 15%) patellar luxations. Distribution of dogs with pat ellar luxations according to breed size included 54 (98%) with medial patellar luxations (MPL) and 1 (2%) with lateral patellar luxation (LP L) in small breeds, 17 (81%) with MPL and 4 (19%) with LPL in medium b reeds, 35 (83%) with MPL and 7 (17%) with LPL in large breeds; and 4 ( 67%) with MPL and 2 (33%) with LPL in giant breeds. Medial patellar lu xation was observed in 110 dogs and 14 dogs had LPL. Cases of MPL and LPL in the same stifle or of medial and lateral patellar luxation in c ontralateral stifles in the same dog were not observed. Surgical corre ction was performed primarily in dogs with grade-3 and grade-4 patella r luxations. Medial patellar luxations and LPL were detected in all br eed categories. Small-breed dogs were admitted almost exclusively with MPL. Lateral patellar luxation was found uncommonly; however, it was observed more often in larger-breed dogs. Prevalence of MPL was greate r, when compared with that for LPL, in every size/breed category.