Aim: To describe a novel; approach for total knee arthroplasty in the face of a chronic irreducible lateral dislocation of the patella.

Method: The patient was a 74 year old female with severe osteoarthritis of both knees and chronic irreducible lateral dislocation of the patellae. The degree of lateral dislocation was more severe on the left side. For the less severe knee, a standard medial approach was performed for the total knee arthroplasty and this was combined with an extensive lateral retinacular release and also with the use of a rotating platform on the tibial side. This approach failed to centralise the patella. On the side of the severe lateral dislocation of the patella, a lateral subvastus approach was performed. This was combined with a tibial tubercle osteotomy with medialisation and three degrees of external rotation of the femoral component.

Result: This approach centralised the patella and produced a very favorable clinical outcome with 0 to 105 degrees of flexion, much improved quadriceps strength, and excellent pain relief.

Conclusion: In the presence of osteoarthritis of the knee and a chronic irreducible later dislocation of the patella, the use of a lateral subvastus approach to the knee combined with medialisation of the tibial tubercle should be considered for the performance of a total knee arthroplasty