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Luxating Patella


Medial patellar luxation in 16 large dogs. A retrospective study. Vet Surg. 1992 Jan-Feb;21(1):5-9.

Remedios AM, Basher AW, Runyon CL, Fries CL.

Department of Veterinary Anesthesiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.

Unilateral medial patellar luxation was diagnosed in 10, and bilateral medial patellar luxation in six, large and giant-breed dogs (22 stifles). Lameness occurred in five dogs after trauma or surgery, and 11 dogs had no known predisposing history. The mean age at presentation was 25 months, and the mean time from initial onset of clinical signs to diagnosis was 13 weeks. All traumatic or iatrogenic luxations (five dogs) were unilateral. Luxations presumed to be congenital were unilateral in five dogs and bilateral in six. The grades of medial patellar luxation were I (1 stifle), II (11 stifles), III (9 stifles), and IV (1 stifle). Preoperative function was good (1 dog), fair (9 dogs), and poor (6 dogs). Surgical correction was performed in dogs with grades II, III, and IV luxations (21 stifles). Complications included one wound dehiscence and trochlear wedge migration, one pin loosening, and one persistent lameness caused by lymphoplasmacytic synovitis. Long-term follow-up was available in 13 dogs (18 stifles). Function was judged by owners to be excellent in seven dogs, good in five dogs, and poor in one dog. Surgical treatment of grades II and III luxations yielded good (8 stifles) and excellent (9 stifles) results, while one grade IV luxation had a poor long-term outcome.

Patellar luxation in 70 large breed dogs.  J Small Anim Pract. 2006 Jan;47(1):3-9.  Gibbons SE, Macias C, Tonzing MA, Pinchbeck GL, McKee WM.

Willows Referral Service, 78 Tanworth Lane, Solihull B90 4DF.


OBJECTIVES: To report the signalment, history, clinical features, and outcome in dogs weighing greater than 15 kg, treated surgically and non-surgically for patellar luxation. Risk factors for the development of patellar luxation, postoperative complications, and outcome were evaluated. METHODS: Details regarding signalment, bodyweight, breed, aetiology, unilateral or bilateral luxation, duration of lameness, grade of luxation, direction of luxation, grade of lameness at presentation, concomitant cranial cruciate ligament rupture, method of treatment, surgical technique, surgeon, and complications were obtained from the medical records. Outcome was graded as excellent, good, fair, or poor, according to the degree of lameness. RESULTS: Seventy dogs (45 males and 25 females) were included. Thirty-five had bilateral luxations (105 limbs). Mean age was two years, and mean weight was 30 kg. The relative risk for Labrador retrievers was 3.3 (P<0.001). All luxations were developmental. Luxations were medial in 102 stifles and lateral in three. Fourteen stifles had concomitant cranial cruciate ligament rupture. As the grade of patellar luxation increased, so did the grade of lameness (P<0.001). Surgery was performed in 70 stifles, and outcome was excellent/good in 94 per cent and fair/poor in 6 per cent of stifles. Complications occurred in 29 per cent of stifles, and increasing bodyweight was found to be a risk factor (P=0.03). Thirty-five stifles were managed non-surgically, and outcome was excellent/good in 86 per cent and fair/poor in 14 per cent of stifles. CLINICAL SIGNIFICANCE: In view of the potential risk of postoperative complications, all surgically treated cases of patellar luxation in large breed dogs should be managed with a femoral trochleoplasty, a tibial tuberosity transposition (stabilised with K-wires and a tension band wire), and soft tissue releasing and tightening procedures.

Frequency and distribution of medial and lateral patellar luxation in dogs: 124 cases (1982-1992). J Am Vet Med Assoc. 1994 Sep 1;205(5):716-20.  Hayes AG, Boudrieau RJ, Hungerford LL.

Department of Surgery, School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.


From the medical records of 124 dogs, patellar luxations were classified as congenital or acquired, medial or lateral, and unilateral or bilateral; were graded 1 to 4; and were subdivided according to size of dog. The 4 breed-size categories were based on guidelines from American Kennel Club standards for adult height and weight. Findings from these records were compared with the results from dogs with other orthopedic problems. A majority of dogs had congenital (91; 82%), as opposed to acquired (17; 15%) patellar luxations. Distribution of dogs with patellar luxations according to breed size included 54 (98%) with medial patellar luxations (MPL) and 1 (2%) with lateral patellar luxation (LPL) in small breeds, 17 (81%) with MPL and 4 (19%) with LPL in medium breeds, 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 luxation 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 contralateral stifles in the same dog were not observed. Surgical correction was performed primarily in dogs with grade-3 and grade-4 patellar luxations. Medial patellar luxations and LPL were detected in all breed 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 greater, when compared with that for LPL, in every size/breed category.

University of Utrecht (University)

Completed AKCCHF Grant No: 580: Patella Luxation in Dogs: A Molecular Approach

Disease(s): Orthopedic Disease

Sponsor(s): Bichon Frise Club of America, Inc., Chihuahua Club of America, Chinese Shar-Pei Charitable Trust, Flat-Coated Retriever Foundation, Orthopedic Foundation for Animals

Researcher(s): Herman A.W. Hazewinkel, DVM, PhD 

Breed(s): Flat-Coated Retriever


Patella luxation (PL) occurs in both small and large breed dogs. Among the large breed dogs, the Flat-Coated Retriever seems to be predisposed to the condition. A survey in 354 Flat-Coated Retrievers revealed that 40 percent were affected with some degree of PL. Males and females were equally affected. A positive correlation was found between the occurrence of PL in the parent(s) and that in the offspring. An autosomal recessive mode of inheritance was suggested. The Flat-Coated Retriever has an annual birth rate of 700 pups in the Netherlands; 75 percent of the owners are members of the Dutch Flat-Coated Retriever Club (FRC). Since 1985 more than 3100 Flat-Coated Retrievers have been clinically investigated by the same specialist and findings are available in a database. At least 20 of the recently included litters had several littermates positive for PL. The genetic research proposed in this project is affected sibling pair analysis. This method compares pair-wise the DNA of littermates with PL and eventually highlights gene variants which are shared by most or all affected dogs. The advantage of this method is that we can develop a DNA-screening test for patella luxation without knowing at the outset the gene(s) involved in the development of PL.

Title: Patellar Luxation in Large Breed Dogs

A BRIDGE TO THE FUTURE Veterinary Conference, August, 2003, August 10, 2003 


Patellar luxation, medial or lateral is a relatively common cause of pelvic limb lameness in young, large breeds of dogs. Medial patellar luxation (MPL) is more common than lateral patellar luxation (LPL). Skeletal deformations such as femoral bowing complicate or predispose patellar luxation in dogs. Failure to identify and correct such deformations may be especially problematic in large breeds. This presentation proposes indications for femoral osteotomy, discusses current investigational surgical methods, and highlights areas of current research.



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