Patella Luxation

The dog’s knee (termed the ‘stifle’) consists of the kneecap (the ‘patella’), and the thigh bone (‘femur’) resting on top of the shin bone (‘tibia’). The patella is within the quadriceps muscles. These muscles originate at the top of the femur and run down the front of the bone, crossing the stifle to attach to the front of the tibia. When the quadriceps muscles contract (shorten) the stifle straightens. The patella is located in a groove on the front of the bottom of the femur, maintaining the quadriceps muscles in position. It is simply a mineralisation within the quadriceps muscles. Therefore, when the patella dislocates (or luxates), the entire quadriceps mechanism dislocates.

If the femur and tibia are well aligned then the patella (and associated quadriceps muscles) will not luxate. Certain (mild) bony deformities in the femur and/or tibia can permit luxation of the patella.

Our surgical approach to patellar luxation has two aims: first to increase the resistance to dislocation of the patella (usually involving deepening the groove, but groove replacement with a prosthetic groove is also possible) and second to realign the femur and tibia so that the quadriceps mechanism functions without luxation (usually this is performed by adjusting the position of parts of the tibia or femur). These procedures are routine at Wessex Veterinary Orthopaedics and carry an excellent prognosis.

We are involved in education of the veterinary profession regarding options and techniques for addressing patellar luxation* . We also reported the first case of patellar luxation addressed through femoral deformity correction and fixation using an interlocking nail†.

We were among the first to offer a guarantee to cover the costs of complications (T&Cs apply) when we worked together at another centre and we are pleased to offer this peace-of-mind at Wessex Veterinary Orthopaedics.