The day my 3rd SV was due to be flown to me, the breeder called and said that he had a little mishap at the vets and had an injured rear leg that the vet said wasn't serious and would heal without a hitch. When the kitten arrived home and I let him out of the carrier, I was horrified at the injury. He could barely put weight on the leg and when he jumped, he had to use his hip to get his leg up. I took him to the vet the next day and he had luxating patella in both knees -- and one was really bad. We quickly got on a phone with a specialist who agreed to see him and said that it would cost $4000 to repair each knee and there was no guarantee that the surgeries would be successful. He was a very large kitten and destined to be a very large cat. I was sick. Called the breeder and she was hesitant about helping with cost of surgeries without a second opinion. I sent the cat back and asked for a refund. I was devastated because we fell in love with him within a second -- he had an exceptional personality and he was a marble, which I had wanted for a long time.
After I dropped him off at the airport, I sat in my car and sobbed for an hour, didn't sleep for weeks, and kept in contact with the breeder for 2 yrs to stay current on the cat's health. She didn't get him the surgeries and adopted him out to someone else who was willing to take the chance on falling in love with a cat who would likely be impaired for life and perhaps have shorter life due to ongoing pain and complications from the injured joints. I just couldn't take that chance. And, I had just lost my soul mate DSH and had an elderly DSH at the time who needed constant vet care and I just wasn't willing to spend $8000 on iffy outcome surgery and nurse an active cat back to health twice.
I'm sure your breeder will either keep the cat or adopt him out after she has done all she can to get the leg to develop properly. Your breeder has integrity for not placing the cat at this time. I think that perhaps from her point of view, it's the only way she can guarantee that everything that can be done for him will be done.