Femoral condyle lesion similar to osteochondritis dissecans.

Dear Sir, I would like to report an interesting case of a two-year old, female, spayed Bengal cat with a lesion similar to osteochondritis dissecans (OCD) of the medial femoral condyle with concurrent distal femoral varus, medial patella luxation and hip dysplasia. The cat was presented with an intermittent, mild left hindlimb lameness, which the owner reported to be associated with an audible ‘click’. Clinical examination was unremarkable other than luxation of the left patella with flexion of the stifle and concurrent internal rotation of the tibia which spontaneously repositioned with stifle extension. An effusion of the left stifle, and signs of mild resentment to extension of the coxofemoral joints bilaterally were also present. Palpation of the right stifle was unremarkable. Under general anaesthesia plain radiographs of the pelvis revealed mild bilateral hip dysplasia with very early signs of osteoarthritis. Orthogonal radiographs of the left stifle revealed a well-defined, smoothly-marginated mineral opacity within the craniomedial aspect of the intercondylar notch 3 mm x 1 mm in size, distal femoral varus, a medially positioned patella within the femoral trochlear, and new bone formation on the distal pole of the patella ( Fig. 1). Orthogonal views of the right stifle revealed distal femoral varus and a fine mineralised streak in the craniomedial aspect of the intercondylar notch. The right patella was positioned centrally in the femoral trochlear. Arthroscopy of the left stifle using a 1.9 mm arthroscope via a standard craniolateral scope portal and craniomedial instrument portal (which