Breeding OFA clear dogs will help but keep in mind that a dog that is clear at one year may not be clear at 4 years of age. Also keep in mind that the test for patellas is not an xray but an exam be a licensed Vet - not necessarily a orthopedic specialist. What one Vet would grade as clear, another might grade as a 1.
This is an issue with all toy breeds so try to breed good stifles but keep in mind that good stifles can produce bad stifles. A dog with a finer bone is more likely to luxate since the patellar notch of the finer bone tends to be more shallow so it can wear smoooth more quickly. There are many contributing factures to patella luxation such as the dog being over weight, lack of exercise and poor muscle tone, running and jumping on slick surfaces and so forth as well as heriditary factors. Yes, it would be wise to know if there were cases of it cropping up in the pedigree of the potential mates but it is very rare to find a line that is totally free of it.
Best of luck.
Charlie |