Hip resurfacing arthroplasty (HRA) is being done on young, active adults with advanced arthritis. HRA is a type of hip replacement that replaces the arthritic surface of the joint but removes far less bone than the traditional total hip replacement.
Maintaining vascular supply (blood flow) to the hip during HRA is important. Reduced blood flow can cause early failure of the implant. In this study, blood flow to the femoral head is measured before, during, and after the HRA procedure in 10 patients.
All patients had a surgical dislocation required for hip resurfacing. The femoral head was dislocated anteriorly (forward). A laser probe was placed in the head of the femur to measure blood flow. Measurements were taken. The procedure was carried out, and a final blood flow reading was taken.
The results showed a 70 per cent decrease in blood flow to the head of the femur after standard reaming and preparation for the HRA. This study shows that hip resurfacing interferes with the blood supply. The risk of implant loosening and bone fracture increases with decreased blood flow to this area.
Although blood flow to the femoral is not disrupted when it is dislocated, the cylindrical reamer cuts off all of the reticular vessels entering the femoral head. Reticular describes a network of blood vessels along the surface of the bone.
The authors advise surgeons to direct the cylindrical-shaped tool used as a reamer superolaterally (up and out). At the same time, it’s best to stay as close to the inferomedial (lower, inner) neck of the femur. Suggestions were also made to use a larger femoral implant. Problems with this solution are discussed.