Hip dysplasia

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Characteristic flattening of the acetabulum in a dog with CHD[1]
Post-operative radiograph showing excision arthroplasty of the left femoral head[2]
Ventrodorsal postoperative radiograph after implantation of a modular hybrid total hip prosthesis. Note the uncemented acetabular cup and the cemented femoral stem[3]

Canine hip dysplasia (CHD) is a genetic disease of the canine hip, which may occur unilaterally or bilaterally.

This condition is a leading cause of osteoarthritis in large-breed purebred and cross-bred dogs such as German Shepherd, Burnese Mountain Dog, Great Dane, Newfoundland, Labrador Retriever, Leonberger, Irish Wolfhound and Rottweiler.

The disease has a partly genetic, multifactorial aetiology and is often evident at birth, manifesting from 3 - 4 months of age in severely affected pups. Because of the genetic underpinning of this condition, concurrent elbow dysplasia is frequently observed[4].

This disease is caused by congenital maldevelopment of the hip joint with characteristic shallow acetabulums, resulting in joint laxity. As the pup grows, the joint laxity results in abnormal wear of the femoral head against the acetabulum, resulting in excessive erosion, arthritis and secondary osteoarthritis. This disease mirrors the frequently observed human congenital hip dysplasia/subluxation which is readily corrected with conservative bracing.

Clinically affected dogs usually present with hind-leg ataxia, reluctance or inability to stand, reduced exercise intolerance and stiffness after exercise.

Diagnosis is usually attained by clinical signs (characteristic 'bunny-hopping' or waddling), evidence of pain and joint laxity during hip manipulation.

The Ortolani test may assist a diagnosis and can be performed under sedation, where axial pressure is placed on the femur to elicit any tendency for subluxation.

Ultrasonography can also be used as an adjunct to establish the presence of hip joint disease but cannot be used as a predictive tool[5].

Radiography is usually required for a definitive diagnosis, although experience is essential and interpretation varies between clinicians[6].

Diagnostic as well as predictive radiographs are usually taken from 5 - 6 months of age in predisposed breeds or those at risk which are potential breeding dogs[7].

A standardized radiographic technique is normally employed in order to assess the extent of dysplasia. This involves placing the dog in dorsal recumbency with the hips extended and legs placed in parallel using slight internal rotation to render the patellae directly above the stifle joint[8].

Scoring of hips follows the recommendations of the PennHIP[9] or British Veterinary Association Hip Traits score[10] which are based on a number of criteria, including:

  • Norberg Angle
  • Subluxation
  • Cranial Acetabular Edge
  • Dorsal Acetabular Edge
  • Cranial Effective Acetabular Rim
  • Acetabular Fossa
  • Caudal Acetabular Edge
  • Femoral Head/Neck Exostosis
  • Femoral Head Recontouring

Scoring ranges from 0 - 6, with 0/6 being a good score and 6/6 implying severe hip dysplasia[11].

A differential diagnosis for this condition would include cauda equina syndrome, achondroplasia, hypertrophic osteodystrophy and Legg-Calve-Perthes disease.

Treatment involves either conservative medication or surgical intervention, depending primarily on the severity of the disease and the breeding potential of the dog.

Non-surgical intervention usually requires long term palliative treatment with acupuncture, activity restriction, physiotherapy and NSAID-based medications such as carprofen, tramadol, meloxicam[12], gabapentin or in severe cases, prednisolone[13].

Use of exercise has significant benefits in long-term therapy associated with osteoarthritis, and leash-held walking is recommended in dogs that are not unduly ataxic or in pain[14].

Adjunct medication such as pentosan polysulfate, glucosamine, veterinary therapeutic diets rich in omega-3 fatty acids[15], curcumin[16] and root extracts of Brachystemma calycinum (an indigenous plant of southwestern China)[17] have predictable improvements in clinical amelioration of symptoms.

Products such as neutraceuticals[18] and fish oils[19] appear to not benefit pain scores in dogs affected by this condition.

Preventative measures include ensuring that puppies under 4 months old have restricted access to stairs and allowed outdoor exercise on soft ground in moderately rough terrain to decrease the risk of developing hip dysplasia[20]. Weight management is critical in obese patients.

The use of the Pavlik harness has been successfully employed in the treatment of human congenital hip dysplasia but is currently not utilized in dogs[21].

Managing chronic pain is the critical aspect of this relatively incurable disease, affording as good quality of life as possible based on economic feasibility and response to medical and physical therapy[22].

Surgical corrective techniques include juvenile pubic symphysiodesis (dogs <6 months)[23], femoral head excisional arthroplasty (ostectomy)[24], double or triple pelvic osteotomy (dogs > 10kg; osteotomy of the ilium, pubis, and ischium)[25], myotomy of the superficial gluteal muscles, gluteal tenotomy and gluteal tenodesis[26].

In severe cases, total hip replacement may be considered (dogs >20 kg), although expensive and not without complications[27].

CHD is a significant welfare problem and may result in significant disability and lead to euthanasia on humane grounds.

References

  1. Maristavet
  2. Whitebear Animal hospital
  3. Minto BW et al (2011) Modular hybrid total hip arthroplasty. Experimental study in dogs. Acta Vet Scand 53:46
  4. Krontveit RI et al (2012) The effect of radiological hip dysplasia and breed on survival in a prospective cohort study of four large dog breeds followed over a 10 year period. Vet J 193(1):206-211
  5. Fischer A et al (2010) Static and dynamic ultrasonography for the early diagnosis of canine hip dysplasia. J Small Anim Pract 51(11):582-588
  6. Verhoeven GE et al (2010) The effect of a technical quality assessment of hip-extended radiographs on interobserver agreement in the diagnosis of canine hip dysplasia. Vet Radiol Ultrasound 51(5):498-503
  7. Hartmann P et al (2012) Multivariate prediction of breeding values for canine hip and elbow dysplasia as well as humeral osteochondrosis in the Bernese mountain dog. Berl Munch Tierarztl Wochenschr 125(9-10):432-440
  8. Gibbs C (1997) The BVA/KC scoring scheme for control of hip dysplasia: interpretation of criteria. Vet Rec 141:275–284
  9. Sondel JA (2010) Sensitivity versus specificity of PennHIP as a screening test for osteoarthritis. J Am Vet Med Assoc 237(8):899
  10. Wilson BJ et al (2012) Heritability and phenotypic variation of canine hip dysplasia radiographic traits in a cohort of Australian German shepherd dogs. PLoS One 7(6):e39620
  11. Comhaire FH & Schoonjans FA (2011) Canine hip dyslasia: the significance of the Norberg angle for healthy breeding. J Small Anim Pract 52(10):536-542
  12. Wernham BG et al (2011) Dose reduction of meloxicam in dogs with osteoarthritis-associated pain and impaired mobility. J Vet Intern Med 25(6):1298-1305
  13. Kirkby KA & Lewis DD (2011) Canine Hip Dysplasia: Reviewing the Evidence for Nonsurgical Management. Vet Surg Dec 8
  14. Bockstahler BA et al (2012) Hind limb kinematics during therapeutic exercises in dogs with osteoarthritis of the hip joints. Am J Vet Res 73(9):1371-1376
  15. Moreau M et al (2012) Effects of feeding a high omega-3 fatty acids diet in dogs with naturally occurring osteoarthritis. J Anim Physiol Anim Nutr (Berl) Jul 14
  16. Colitti M et al (2012) Transcriptome modification of white blood cells after dietary administration of curcumin and non-steroidal anti-inflammatory drug in osteoarthritic affected dogs. Vet Immunol Immunopathol 147(3-4):136-146
  17. Moreau M et al (2012) Brachystemma calycinum D. Don Effectively Reduces the Locomotor Disability in Dogs with Naturally Occurring Osteoarthritis: A Randomized Placebo-Controlled Trial. Evid Based Complement Alternat Med 2012:646191
  18. Vandeweerd JM et al (2012) Systematic review of efficacy of nutraceuticals to alleviate clinical signs of osteoarthritis. J Vet Intern Med 26(3):448-456
  19. Hielm-Bjorkman A et al (2012) An un-commissioned randomized, placebo-controlled double-blind study to test the effect of deep sea fish oil as a pain reliever for dogs suffering from canine OA. BMC Vet Res 8(1):157
  20. Krontveit RI et al (2012) Housing- and exercise-related risk factors associated with the development of hip dysplasia as determined by radiographic evaluation in a prospective cohort of Newfoundlands, Labrador Retrievers, Leonbergers, and Irish Wolfhounds in Norway. Am J Vet Res 73(6):838-846
  21. van de Sande MA & Melisie F (2012) Successful Pavlik treatment in late-diagnosed developmental dysplasia of the hip. Int Orthop 36(8):1661-1668
  22. Fox SM (2012) Painful decisions for senior pets. Vet Clin North Am Small Anim Pract 42(4):727-748
  23. Dueland RT et al (2010) Canine hip dysplasia treated by juvenile pubic symphysiodesis. Part I: two year results of computed tomography and distraction index. Vet Comp Orthop Traumatol 23(5):306-317
  24. Johnson KA (2010) Outcome of femoral head ostectomy in dogs and cats. Vet Comp Orthop Traumatol 23(5):3-4
  25. Tong K & Hayashi K (2012) Obturator nerve impingement as a severe late complication of bilateral triple pelvic osteotomy. Vet Comp Orthop Traumatol 25(1):67-70
  26. Rochereau P & Bernardé A (2012) Stabilization of coxo-femoral luxation using tenodesis of the deep gluteal muscle. Technique description and reluxation rate in 65 dogs and cats (1995-2008). Vet Comp Orthop Traumatol 25(1):49-53
  27. Guillaumot P et al (2012) Outcome and complications after dual mobility total hip replacement. Fifty cases with a minimum of six months clinical and radiographic follow-up. Vet Comp Orthop Traumatol 25(6):511-517