Histology of impacted bone–graft incorporation

We describe the histologic findings of 31 tissue samples from 21 cases in 19 different patients taken 1 to 48 months after revision arthroplasty and impaction grafting in the hip (Lubinus SP-II prosthesis Waldemar Link, Hamburg, Germany, or Charnley Elite prosthesis, Johnson & Johnson, New Brunswick, NJ) and the knee (Link Rotation Knee Waldemar Link). One month after surgery, a fibrous stroma and some newly formed woven bone were found in the graft bed. After 4 months, many of the dead trabeculae in the graft bed had layers of living bone and osteoid in all samples. These layers, indicating a gradual ingrowth of living bone, increased over time. In the proximal end of the femur examined after 48 months, a significant proportion of the graft bone remained dead, whereas in the rest of the femur, the bone healing was complete. A similar but possibly less frequent bone formation was found in the 2 cases evaluated after a revision total knee arthroplasty combined with impaction grafting.