The weight of the dog has some bearing on the outcome on this surgery.In the surgery, the ball portion of the hip joint (the femoral head) isremoved and the bone smoothed, if necessary, so that no bone to bone contactoccurs between the pelvis, which contains the now empty socket and theremaining portion of the femur. The joint is not stabilized, it is destroyed.While that sounds bad, in almost all dogs under 40 to 50 lbs in weight,this surgery will provide reasonable comfort. A "false joint" forms, consistingof fibrous scar tissue around the bone end. This forms in the muscles overthe hip, which fortunately are strong enough to provide some stability.It is less painful than leaving the dislocated femoral head rubbing againstthe pelvic bone.
The shoulder joint is naturally constructed in a similar fashion, althoughit has more stabilization. In dogs over 50 pounds of body weight thereis more concern that the joint will not be functional due to the need formore weight bearing capacity. Most of the time, there is still reasonablecomfort even in big dogs but the outcome is more questionable in thesedogs.
There are alternatives.
1) Stabilization of the joint can be attempted. Many vets arereluctant to do these surgeries because some of them are technically difficultand all of them have a moderate failure rate. It is disconcerting to dosurgery, collect a large fee, have to explain the failure to the clientand then have to go back and do a femoral head ostectomy anyway. Thereare several possible stabilization procedures, including pinning the femoralhead to the hip socket, moving the portion of the bone where muscle attachmentoccurs to a different site on the femur to provide more stability, togglepinning the femoral head and several other stabilization techniques. Itmay be necessary to ask for referral to a surgical specialist for theseprocedures as many general practitioners are not comfortable doing them.
2) Total hip replacement. This is an option in some cases whenhips can not be stabilized but it is necessary to consider this on a caseby case basis. Again, this surgery requires referral to a surgical specialistin most cases. Very few veterinary practices have the capability of doinghip replacement surgery.
If an alternative stabilization technique doesn't work, femoral headostectomy remains an option. You do end up paying for two surgeries whenone of the other stabilization methods fail but if they work, the outcomeis better for your dog. The success rates of the various surgeries woulddepend a lot on the individual surgeon's experience and skill.