Monday, July 29, 2013

Good Advice for those patients who have MoM implants and have not been seen by your surgeon.


The changing paradigm of revision of total hip replacement in the presence of osteolysis.


Department of Orthopaedic Surgery, The Ottawa Hospital, Ottawa, Ontario, Canada.


Osteolysis tends to remain clinically silent and presents a treatment challenge. In the past, the progression of implant wear was used to determine the timing of interventions. Recent reports of lesions associated with metal-on-metal implants and trunnion corrosion with femoral head sizes larger than 32 mm suggest that other mechanisms of wear debris production may be present; observation alone may not provide adequate monitoring. Advanced imaging modalities, such as MRI, should be used along with routine radiography to assess soft-tissue involvement and the size of osteolytic lesions. Intraoperative mechanical stress applied to the acetabular cup helps determine if revision or retention is selected when osteolysis is present. Options for the management of acetabular osteolysis include porous metal cups, oblong cups, antiprotrusio cages, impaction grafting, structural grafts, and, more recently, versatile porous metal cups. Porous metal cups can be used with or without augments or as cup-cage constructs. Porous metal cups have shown excellent results at short-term follow-ups. Modular, uncemented, titanium stems are now more commonly used for femoral revisions. Impaction grafting and allograft-prosthesis composites are occasionally useful in femoral revision surgery. A high incidence of adverse tissue reactions has been reported with metal-on-metal bearings with large heads. Recent focus also has been directed to debris generation by the modular junctions in these bearings. Removal of all sources of debris generation should be attempted during revision of metal-on-metal hip replacements. A thorough débridement of soft-tissue masses and the use of ceramic heads should be considered.

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