Aseptic loosening of the femoral implant after cemented total hip arthroplasty in dogs: 11 cases in 10 dogs (1991-1995)

Abstract

Aseptic loosening of the femoral implant (ALFI) was diagnosed in 10 dogs that had undergone cemented total hip arthroplasty (THA). One dog had bilateral ALFI. Loosening developed at the stem-cement interface a mean of 30 months after THA. The most common clinical sign was intermittent subtle or non-weight-bearing lameness. On radiographs obtained after THA, the distal stem tip was in contact with the cortical endosteum in all dogs. Radiographic changes at the time of diagnosis of ALFI included asymmetric periosteal reaction along the femoral diaphysis (n = 11), radiolucent zone at the stem-cement interface (6), altered implant position (4), and femur fracture (1). Surgical revision resulted in a good or excellent outcome in 9 dogs. In 1 dog, the implant became infected. In another, aseptic loosening recurred. Aseptic loosening of the femoral implant was significantly more common when initial positioning of the implant resulted in contact between the distal tip of the implant and cortical endosteum than when there was no contact.