My sister's Pom/Chihuahua mix has Legg?Calvé?Perthes/aseptic necrosis of the femoral head except the X-rays actually show a thickening of the neck. She needs an FHO (Femoral Head Ostectomy), a procedure where they surgically remove the head from the femur (leg bone). From what we can tell, the procedure is quite common, so I'm looking to see what others have paid for similar veterinary surgery. No cliffs needed, the post ends here unless you want more info; perhaps for your own undiagnosed pet The surgeon described it thusly: Aseptic necrosis of the femoral head is common in small breeds. When it happens, normally blood vessels at the top/head of the hip-bone inside of the ball joint/socket die for an unknown genetic reason, sometimes "bilaterally" (IOW, "in both legs," though just one in our case). New blood vessels (sometimes?) form and it continues to grow abnormally. In this case the abnormal growth was in the neck instead of the head, as is shown by the neck thickening on the X-ray of her right-rear leg. The head looks perfect. The FHO surgery USUALLY removes both the neck and the head anyway, so the only difference will be ensuring that the neck is removed. Anyone wanting to know the symptoms for their own pet: She is almost a year and two months old. Almost 7 months ago we noticed her lifting her right leg often, usually when stopping to sniff things during walks. This made it seem more like a habit than a pain because she still played vigorously with people and other animals. I can't recall if she yelped before we took her in for an X-ray, but we took her in as soon as we realized that it was getting worse and was likely pain-related and though she NEVER snapped at anyone in her life before that, she yelped and snapped when the vet was feeling under that hip. That was February and the vet did not see anything. They sent us home saying that it may just be a bruised/sore muscle prescribing rest, limited walks, no jumping, etc, but they wanted to do follow-up X-rays when we returned to have her fixed "soon." This was because they feared necrosis of the femoral head and believed that we may have caught it too early to be seen on X-rays. It worsened further while we weren't nearly ready to have her spayed so we called and asked if it was OK to give her aspirin, "perhaps to assist the healing in case there was any inflammation that may be aggravating it." They suggested one-quarter of a baby aspirin (1/4th of 81mg) daily. The surgeon later (today) said that, though it was an appropriate dosage, it is recommended AGAINST these days due to more recent studies showing that even small size-appropriate dosages usually lead to symptom-less ulcers in dogs. FWIW, she's 6lbs and seemed to be doing better while she was on aspirin... to the point where we eventually stopped giving it to her. Anyway, when it came time to have her fixed, they did the surgery and just gave her back to us. We asked if they took the X-rays and they said that they didn't believe that it was needed because she was doing better. Though she wasn't as bad as she had been on some days, we still felt that this was due to the aspirin masking the pain and that we should still have the X-rays so that we don't squander any chance at a useful early detection. Anyway, we got a cat a week before my sister, her owner, entered the hospital for two weeks. Just as she entered the hospital, the dog's leg worsened to the point where she frequently walked on three legs, though she still played, ran, and jumped like nothing was wrong, I would hear a loud yelp several times a day while she was playing with the cat (they love playing together and play all day). Even after the painful-sounding yelps, I'd look and she would continue playing like nothing happened. I couldn't do much while her mother was in the hospital, so it continued to get worse. Even though everything looked fine when she would play and run at lightning speed, turning and cornering like a wild rabbit, it looked painful when she walked on three legs during her walks. The surgeon found that this disuse had caused a 1" measured difference in leg muscle due to atrophy and increased muscle-mass (compensation) on the other leg. This is the primary reason she suggests FHO instead of just pain-killers. Their estimate was ~$2,300 to $2,900 including all follow-up visits. We can't afford it without some kind of assistance. Even the two X-rays ($270) almost broke us. The visit with the surgeon today cost us $140. They said that the condition did show on the original X-rays and HAD worsened, but the vet was likely looking for necrosis and not thickening of the neck. The follow-up visit to the vet when we had the second X-rays take was not very useful originally. They basically said that they didn't know what it was or what they could do, but they would consult with the original doctor and get back with us (same clinic). A friend who was a veterinary nurse brought up the specialists (VCAemergency.com) and suggested FHO like the original doctor and we pursued it, eventually getting confirmation from all parties.