Page 399 - Canine Lameness

20.8 ­liopsoas Tenninopathy 371

backwards) and secondary hip pathology (subluxation), patellar luxation, and eventually ankylosis
of the stifle joint (Vaughan 1979).

20.7.2.3 Diagnostics
Young dogs with no known traumatic injury should have N. caninum and toxoplasmosis titer levels
checked and/or muscle biopsy taken for histopathology which reveals multifocal lymphohistio-
cytic myositis (Crookshanks et al. 2007). Histologically, the muscle fibers are replaced by fibrous
connective tissue in fracture disease.
Radiographs are used to evaluate fracture healing or to evaluate for secondary changes such as
hip luxation and patellar luxation as well as genu recurvatum (Figure 20.16).

20.8 Iliopsoas Tendinopathy

The iliopsoas muscle is comprised of the psoas major and iliacus muscles, whose primary function
is flexion of the coxofemoral joint along with adduction and external rotation of the femur. It also
contributes to core stabilization and flexion of the lumbar spine.
Iliopsoas injuries can present as isolated, acute injuries or as chronic overuse injuries. It has also
been suggested that iliopsoas injury may occur as a secondary, compensatory problem due to a
primary disease (Cabon and Bolliger 2013; Cullen et al. 2017). Since pain upon palpation of the
muscle is often found in conjunction with concurrent orthopedic or neurologic conditions, a thor-
ough evaluation of the patient is essential to ensure a primary injury/pathology is not missed
(Nielsen and Pluhar 2005).
Treatment most frequently is nonsurgical; however, tenotomy of the iliopsoas tendon can be
performed in refractory or severe cases (Stepnik et al. 2006; Ragetly et al. 2009; Cabon and
Bolliger 2013).

20.8.1 Signalment and History HIP REGION
In acute cases, strains most commonly occur when there is a sudden abduction of the limb (Breur
and Blevins 1997). Common history includes slipping while walking, jumping out of a vehicle, or
rough play. During such motions, eccentric contraction is occurring – the muscle is contracted
while being stretched (Nielsen and Pluhar 2005). Chronic injury is thought to be secondary to
microtrauma to the muscle fibers from repetitive use. Sporting and working dogs may be at
increased risk for both forms (Cabon and Bolliger 2013; Cullen et al. 2017).

20.8.2 Physical Exam
Iliopsoas tendinopathy can cause varying degrees of pelvic limb lameness. Degree of lameness var-
ies depending upon severity of the strain. If there is current inflammation of the muscle or there is
significant fibrosis, the femoral nerve may be entrapped causing toe touching to non-weight-
bearing lameness (Stepnik et al. 2006; Adrega Da Silva et al. 2009).
Dogs can present with unilateral or bilateral injury. On gait evaluation, dogs will often have a
shortened stride as they do not fully extend their pelvic limbs. There may be pain with extension of
the hip joint, exacerbated by internal rotation of the limb. Hip extension is often decreased due to
pain or in some cases fibrosis of the muscle. This may occur with primary or secondary compensa-
tory injury.