DISEASE SUMMARY PAGE

Splay Leg in Lagomorphs

Unilateral splay leg. Click here for full page view with caption.

Summary Information
Diseases / List of Miscellaneous / Metabolic / Multifactorial Diseases / Disease summary
Alternative Names Hip dysplasia (B601.11.w11)
Disease Agents
  • This is an inherited developmental musculoskeletal condition. (B602.20.w20, N12.38.w1)
    • This condition is thought to be due to a mutant autosomal gene which is inherited in a simple autosomal recessive pattern. (B601.11.w11, B602.20.w20, B603.3.w3, B604.5.w5)
  • Environmental factors
    • Factors such as floor structure and bedding type may also play a role in the pathogenesis of this condition in young rabbits. (B601.11.w11, J15.28.w1, J495.51.w1)
      • In a study, 22% of rabbits housed on smooth Plexiglas flooring and 7% of those on waxed cardboard developed splay leg, whereas those that were housed on rough flooring (Plexiglas covered with textured strips) did not. (J495.51.w1)
  • Nutritional factors
    • There have been suggestion that high calcium intake may be a possible cause of osteochondrosis in young rabbits. (B601.11.w11)
Infectious Agent(s) --
Non-infectious Agent(s) --
Physical Agent(s) --
General Description
  • "Splay leg" is a non-specific term that is used to describe "any condition affecting the limbs that prevents standing" (B600.12.w12) including a number of inherited developmental abnormalities; the affected animal is unable to adduct one or more limbs, making locomotion difficult. (B600.12.w12, B601.11.w11, B602.20.w20, B606.13.w13, J15.28.w1) 
    • The abnormalities include improper development of the hip joint, long bones, spine, or pelvis. The muscles of the affected limb(s) may still be functional or they may become partially or totally paralysed. (B604.5.w5)
  • Splay leg is usually first noticed in the young rabbit when it begins to leave the nest. (B606.10.w10)
    • From birth up to a few months of age. (B601.11.w11, B603.3.w3, B604.5.w5)
  • "Generalised joint laxity and primary acetabular dysplasia are not implicated in this condition. Abnormalities primarily involve only the bony structures of the femoral neck and subtrochanteric region". (B601.11.w11)
Clinical Signs
  • Splaying of one or more legs. (B600.12.w12, J495.51.w1)
    • The condition can range from relatively mild with the rabbit demonstrating clumsy movement, to a severe disability with the rabbit completely paralysed. (B602.20.w20, B606.13.w13)
  • The rabbit is usually alert and responsive. (B604.5.w5)
  • Slightly stunted growth occurs in some animals. (B604.5.w5)
  • The condition can develop to joint disease in time, including chronic traumatic osteoarthritis, subluxation or dislocation. (B604.5.w5)
  • The hind legs are affected more commonly than the front legs. (B600.12.w12)
Pathology
  • Gross: 
    • Hindlimbs are usually more commonly affected and the possible developmental abnormalities include the following:
      • Femoral neck anteversions (B601.11.w11, B602.20.w20)
      • Femoral head flattening and size reduction. (J495.51.w1)
      • Femoral shaft torsion (B601.11.w11, B602.20.w20)
      • Femoral subluxation or luxation (B601.11.w11, B602.20.w20, B606.13.w13)
      • Hip achondroplasia (B606.13.w13)
      • Hypoplasia pelvis (B606.13.w13)
      • Patellar luxations or subluxations (B601.11.w11, J495.51.w1)
      • Valgus deformity. (J495.51.w1)
    • Forelimb developmental abnormalities include:
      • Shoulder achondroplasia (B606.13.w13)
      • Distal foreleg curvature (B606.13.w13)
  • Histopathology: changes at this level are not a common feature of this condition. (B604.5.w5)
    • Hip joint capsular thickening, formation of fibrocartilage, loss of trabecular bone, bony sclerosis of the proximal femur, hypoplasia of adductor muscle. (J495.51.w1)

Further Information

Susceptibility
  • Pet rabbits. (B602.20.w20)
    • This condition occurs in a variety of breeds and in both sexes. (B604.5.w5)
  • Age: this condition is seen in young rabbits from neonates to juveniles that are several months old. (B602.20.w20, B604.5.w5, B606.13.w13)
Diagnosis 
  • Clinical signs in combination with radiographic findings. (B604.5.w5)
Differential diagnosis
Treatment
  • There is no reported satisfactory treatment for this condition. (B603.3.w3, B604.5.w5)
  • In mild cases, the rabbit may be able to cope with its disability. (B600.12.w12, J15.28.w1)
  • If only a single leg is affected then the rabbit may be able to cope with the disability. Amputation of the affected limb is an option when the animal is old enough to undergo a general anaesthetic. (B603.3.w3, B606.13.w13)
  • Euthanasia is appropriate for most cases, particularly if more than one limb is affected. (B601.11.w11, B602.20.w20, B603.3.w3, B604.5.w5, J15.28.w1)
Prevention and control
  • Do not breed from affected animals or their parents. (B601.11.w11, B602.20.w20, B604.5.w5, J15.28.w1)
Associated Techniques
Host taxa groups /species
Disease Author Dr Debra Bourne MA VetMB PhD MRCVS (V.w5); Nikki Fox BVSc MRCVS (V.w103)
Referees John Chitty BVetMed CertZooMed MRCVS (V.w65)

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