Page 960 - Cote clinical veterinary advisor dogs and cats 4th

470 Hip Dysplasia

Mature patients have progressively worsening ○ Hypertrophic osteodystrophy ○ Increases acetabular coverage of the
hindlimb lameness characterized by ○ Muscle injury (iliopsoas, gracilis, adductor, femoral head and decreases likelihood of
VetBooks.ir • Lameness after exercise • In the mature patient ○ Not recommended in cases with severe
osteoarthritis
pectineus, and sartorius muscles)
• Weight-bearing lameness
○ Patellar luxation
subluxation or luxation
• Exercise intolerance
• Disuse atrophy of pelvic musculature
○ In mature dogs
• Difficulty jumping ○ Cranial cruciate ligament injury • Total hip replacement (THR)
○ Patellar luxation
○ Lumbosacral disease ○ Replaces degenerative joint structures with
PHYSICAL EXAM FINDINGS ○ Polyarthritis synthetic components
Juvenile patients: ○ Bone neoplasia ○ Should be performed by surgeons with
• Pain during extension, external rotation, and ○ Rickettsial and fungal disease (geographic) specific training who do THR with some
abduction of the hip ○ Muscle injury regularity
• Hip joint laxity (positive Ortolani sign) • Femoral head and neck ostectomy/excision
characterized by dorsal subluxation of the Initial Database (FHO or FHNE):
femoral head with the limb adducted, fol- • Orthopedic exam (p. 1143) ○ Young and mature dogs
lowed by a palpable click with reduction of • In the young patient ○ Replaces the painful joint with a
the femoral head when the limb is abducted ○ Palpation of hip joints for Ortolani sign pseudoarthrosis
○ Angle of reduction is the measured point in addition to calculation of angles of ○ Associated with some mechanical gait
at which the femoral head slips back into subluxation and reduction (may require deficit, fatigue with exercise in large dogs
the acetabulum as the limb is abducted. sedation/anesthesia) ○ Immediate postoperative physical reha-
○ Angle of subluxation is the measured point ○ Lateral and ventrodorsal pelvic radiographs bilitation needed for best outcome
at which the femoral head slips out of the ○ After a hip has undergone this procedure,
acetabulum as the limb is then adducted. Advanced or Confirmatory Testing future THR becomes exceptionally dif-
• Poor pelvic limb musculature • Orthopedic Foundation for Animals ficult, with a high complication rate.
• Some dogs have tarsal hyperextension during (OFA) radiographic protocol for subjective • Acetabular denervation
weight bearing. evaluation ○ Neurotomy of nerve fibers in the periar-
• Patient may appear to have an arched spine as • PennHIP or dorsolateral subluxation stress ticular region to partially desensitize the
weight is shifted cranially to the thoracic limbs. radiography protocols for objective evaluation hip joint
• Narrow pelvic limb stance of joint laxity to help predict likelihood of ○ Only a palliative procedure
Mature patient: later osteoarthritis ○ Objective (force plate) evaluations question
• Pain, sometimes crepitus during extension, • Hip arthroscopy to identify ligament and car- efficacy of the procedure.
external rotation, and abduction of the hip tilage damage (clinical relevance is unknown)
• Decreased hip range of motion Chronic Treatment
• Ortolani sign is lost because periarticular TREATMENT Medical management:
fibrosis limits femoral head movement. • Attaining lean body condition is the most
• Hindlimb muscle atrophy Treatment Overview important factor for long-term successful
• Exaggerated hip movement at a walk (see Goals are pain reduction, functional improve- medical management (pp. 700 and 1077).
Video) ment, and restoration of hip congruity/stability • Daily or prn NSAID administration (see
if possible. In cases without complete hip above)
Etiology and Pathophysiology luxation, medical therapy is typically the initial • Analgesia
• A combination of genetic and environmental recommended treatment. In general, medical ○ Amantadine 2-4 mg/kg PO q 24h, and/or
factors causes hip joint laxity, resulting in management and progression of DJD will not ○ Gabapentin 5-10 mg/kg PO q 12-24h,
joint instability and abnormal progression encumber future surgical intervention with hip and/or
of endochondral ossification. replacement or excision arthroplasty. ○ Tramadol 2-4 mg/kg PO q 8-12h, or
• Puppies with a genetic predisposition are ○ Codeine 0.5-2 mg/kg PO q 8-12h, or
born with hips that are grossly normal. Acute General Treatment ○ Buprenorphine 0.01-0.03 mg/kg PO or
Changes in the hip joint begin within the Medical management (p. 1425): via buccal mucosa q 6h (cats), or
first few weeks after birth. • Nonsteroidal antiinflammatory drugs • Adjunctive therapies
• Lameness and gait abnormalities appear (NSAIDs); dosages for dogs: ○ Acupuncture (p. 1056)
between 3 and 8 months of age. ○ Carprofen 2.2 mg/kg PO q 12h, or ○ Rehabilitation with the goal of pain
• In immature animals, lameness may improve/ ○ Deracoxib 1-2 mg/kg PO q 24h, or relief and improving/maintaining muscle
resolve over time as joint stability is gained ○ Meloxicam 0.1 mg/kg PO q 24h, or mass
through periarticular fibrosis. As degenerative ○ Grapiprant 2 mg/kg PO q24h for dogs • Disease-modifying osteoarthritis agents may
changes accumulate, clinical signs of mature > 3.6 kg, or be beneficial.
hip dysplasia develop. ○ Firocoxib 5 mg/kg PO q 24h, or ○ Polysulfated glycosaminoglycan 5 mg/kg
○ Etodolac 10-15 mg/kg PO q 24h IM twice weekly × 4-6 weeks, or
DIAGNOSIS • Analgesia (see Chronic Treatment) ○ Pentosan polysulfate 3 mg/kg SQ or IM
Surgical management (p. 1425): once weekly, or
Diagnostic Overview • Juvenile pubic symphysiodesis (JPS) ○ Oral formulations (glucosamine, chon-
Diagnosis is based on clinical signs of lameness, ○ In immature patients with joint laxity and droitin sulfate, hyaluronan): according to
hip joint laxity or degeneration, and radiographs without DJD (14-20 weeks of age) formulation/labeled instructions
showing a malformed and/or arthritic joint. ○ Minimally invasive; increases acetabular • Nutrition (energy restricted diet, as appropriate)
coverage of the femoral head ○ High-omega-3 fatty acid diet
Differential Diagnosis ○ Not recommended in cases with severe Surgical management:
Any cause of hindlimb lameness: subluxation or luxation • JPS or TPO is performed in some young
• In the immature patient • Triple pelvic osteotomy (TPO) and double animals with hip laxity and minimal degen-
○ Panosteitis pelvic osteotomy (DPO) erative change.
○ Osteochondrosis ○ In young dogs with joint laxity and • FHO or THR is performed in mature
○ Physeal fractures of the femoral head without DJD animals with joint degeneration unresponsive
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