P. 590

An Urban Experience
The treatment of the young dog with HD aims at preventing of DJD. The earliest treatment option for preventing DJD is pubic symphysiodesis. This technique is designed to alter the normal growth of the pelvis to allow acetabular rotation similar to what is accomplished via the TPO procedure. The pubic symphysis is iatrogenically damaged with electrosurgery or staples early in the dog’s development (3-5 months of age)
so that endochondral ossi cation stops. This focal disturbance of growth result in relatively less growth of the ventral pelvis, which results in bilateral acetabular rotation and increased femoral head coverage. Because the technique needs to be performed in very young puppies, early diagnosis is critical. This technique has the advantages of being minimally invasive, resulting in bilateral acetabular rotation, and can be performed in conjunction with a neutering procedure. Early results of this technique in clinical dogs have been very promising.
Triple or double pelvic osteotomy is another surgical procedure designed for the young dog. Ideally, correction takes place prior to skeletal maturity and before secondary changes occur. The goals of TPO are correction of femoral head subluxation and restoration of the hip’s weight-bearing surface area. The ideal candidate for TPO is a young dog (<10 months of age) with clinical signs of CHD, radiographic subluxation, and no secondary OA changes. The procedure involves performing osteotomies in the pubis, ischium, and ilium to allow axial rotation of the acetabulum providing increased dorsal acetabular coverage and weight-bearing surface area. The ilial osteotomy is
then stabilized using a bone plate that maintains the desired degree of rotation. A recent study has shown that no advantage in femoral head coverage or weight- bearing surface area is gained with higher degrees of rotation. Postoperative management involves exercise restriction until radiographically evident healing of the
ilial osteotomy, followed by a gradual return to normal function. Complications associated with TPO include narrowing of the pelvic canal, constipation, urethral injury, overrotation of the acetabulum (resulting in limited femoral extension and abduction), implant failure, infection, sciatic nerve palsy, persistent incongruity, and failure to retard the progression of OA. The critical issue when choosing if to perform DPO or TPO is that the ideal candidates are dogs without symptoms, which poses a question on the ethical decision to perform an invasive procedure with risk of complications. On the other hand, when waiting for clinical signs to present, early signs of DJD may progress and the candidate may not be ideal.
The treatment of the chronic HD follows the principles of management of degenerative joint disease (DJD). Medical management is based on client education
and comprehensive patient management. In order to ef ciently and accurately diagnose, treat, and determine prognoses for DJD patients in practice, it is important
to understand the basics of this condition. Although historically described as a “non-in ammatory” disease, it is now accepted that DJD is an in ammatory condition, but the in ammation is not mediated by neutrophils as in other types of arthritis. Many, many cells and cytokines are involved in the vicious cycle of DJD and it is certainly not yet comprehensively understood. For this reason
the medical treatment of DJD aims at decreasing the in ammation in/around the joint. Strategies to treat
DJD associated with HD include weight loss, low
impact exercise (underwater therapy and swimming are excellent), anti-in ammatory drugs and chondroprotecive agents.
When medical management fails, surgical treatment for HD should be selected. THR is the best treatment option for dogs that are clinically affected with OA resulting from CHD (our opinion). Contraindications include infection, neurologic disease that affects the hindlimbs, concurrent orthopedic problems, and some systemic diseases. THR can be done bilaterally with at least 2-3 months between surgeries. Unilateral THR, however, reportedly results in acceptable function in up to 80% of dogs with bilateral CHD. Postoperative management is vital to successful outcome. For the  rst week after surgery, activity is restricted to leash walking with support of the hindlimbs. Activity restriction should continue for the  rst month, with a gradual return to function 10-12 weeks after surgery. THR is reported to have a 91-95.2% success rate. Complication rates vary widely and decrease with increased surgical experience. Complications include dislocation, osteomyelitis, aseptic component loosening, femoral fractures, and sciatic neuropraxia. Infection is the most severe complication.

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