Carrageenan-induced coxitis in puppies.

We studied the influence of chronic synovitis and joint effusion on the blood supply and growth of the immature femoral head in 12 puppies. Twelve weekly intraarticular injections of Carrageenan solution caused unilateral coxitis with caput magnum formation. Joint pressures in the neutral position were 0.9 kPa in the coxitis hips and -0.5 kPa in the contralateral hips. The joint capsule in coxitis showed hyperemia as measured by tracer microsphere technique. In nonmedicated, awake, standing dogs there was hyperemia of both the femoral head epiphysis and the joint capsule. In all the dogs, acetabular and proximal femoral metaphyseal blood flow was unchanged. In the control group, repeated cannulation and injection of normosaline did not change the hemodynamics, joint pressure, or femoral head size. We found no evidence of femoral head ischemia in coxitis with moderate chronic elevation of resting joint pressure.