Cementless total hip replacement complications.

early osteointegration. On-growth of bone to porous coated prostheses is influenced by many factors such as the composition and topography of the surface, as well as the local biological and mechanical environment in the immediately adjacent bone. Given that the short stem femoral implant is orientated in a more oblique to transverse trajectory, it might be subjected to greater bending moments and cyclic micromotion, than conventional, axially directed medullary stems. Further research is needed to understand the factors about this implant design and its implantation that leads to excessive micromotion at the bone–implant interface and impaired osteointegration. With the increase in number of canine total hip arthroplasties being performed, there are now more cases requiring revision procedures. Whereas revision often involved conversion to a femoral head ostectomy, especially in cases of infection and recurrent luxation, there is now more interest in performing a revision arthroplasty. Two case reports of successful revision of short stem femoral implants with the Zurich femoral component or with the cementless BioMedtrix® components suggest some potential options using currently available implants (2, 7). Also, recurrent luxation of cementless BioMedtrix prosthetic hips in two large dogs was successfully managed by revision surgery to increase the femoral head diameter (3). The rationale being that the larger femoral head increased the impingement-free range-ofmotion of the joint, and also increased the transition distance required for luxation. Design modifications such as increasing femoral head diameter could be a promising option to reduce recurrent luxation in large and giant breed dogs undergoing primary total hip arthroplasty. We look forward to future research evaluating the outcome of such design modifications in larger patient cohorts. Editorial