Abstract
Periprosthetic fractures may occur intraoperatively or postoperatively. The incidence of is approximately 0.6% in primary and 2.4% in revision total hip arthroplasty. Predisposing factors include stress risers, osteolysis, osteopoenia, singly or in combination. Focusing on postoperative fractures, this paper provides a management algorithm.
If the fracture is stable, conservative treatment is appropriate. If the fracture is not stable, one needs to determine whether the prosthesis is loose or not. If the prosthesis is loose, further management will depend on the quality of the bone stock. Good bone stock will allow revision with a long stem or impaction grafting, while poor bone stock will require extensive allografting. Similarly, the adequacy of the bone stock determines the management regime if the pros-thesis is not loose. In the presence of good bone stock, it is usually possible to carry out open reduction and internal fixation. Poor bone stock requires bicortical onlay allografting.
From 1994 to 1998 36 periprosthetic fractures, 14 with stable implants and 22 with unstable, were treated. The stable implants were treated with Dall Miles plates, fixed with cables and crimp-sleeves, bicortical screws distal to the fracture and unicortical screws proximally. The fracture united in 11 hips, two of which subsequently required prosthetic revision for femoral loosening. In one hip the fixation failed with fracture of the cables. Despite other adverse reports, this type of system is recommended for fixation of periprosthetic fractures where the prosthesis is stable.
The 22 periprosthetic fractures with unstable implants were treated using the Bicontact long stem revision implant. Two distal interlocking screws provided early rotational and axial stability, and 14 patients had additional allografting.
Radiological evidence of fracture healing was apparent in all cases. One prosthesis subsided by more than 5 mm with fracture of the interlocking screws. Cementless long stem revision is the treatment of choice for periprosthetic fractures associated with a loose implant.
To ensure successful outcome it is necessary to determine the extent of the fracture, to assess fracture stability and to appreciate the available and appropriate treatment options. It is necessary to ‘be prepared’: these are challenging problems and the final decision often hinges on intraoperative findings.
The abstracts were prepared by Professor M. B. E. Sweet. Correspondence should be addressed to him at The Department of Orthopaedic Surgery, Medical School, University of Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193 South Africa
