Friday, March 12, 2004
Preoperative bone loss and cement technique at the time of revision surgery can affect the long-term durability of a cemented revision following aseptic loosening of an uncemented stem, confirmed researchers for Poster Exhibit P011.
Researchers studied 26 hips in 23 patients who underwent cemented revision for aseptic failure of an uncemented femoral component between January 1985 and January 1993. They examined the ability of cemented revisions to form a lasting microinterlock with the endosteal surface of bone following an uncemented primary hip.
As part of the study, researchers obtained both preoperative and postoperative Harris Hip Scores for each patient. Preoperative radiographs were evaluated for osseous deficiencies based on the classification system of Mallory. The cementing technique was graded according to the criteria of Barrack, et al, on the postoperative radiographs. Radiographic loosening of the femoral component was classified according to the system of Harris and McGann.
Researchers were able to follow 20 patients (23 hips) with a cemented revision both clinically and radiographically for a minimum of seven years. The average follow-up was 98 months (range 7 to 12 years). No patients were lost to follow-up.
During this follow-up, there were three femoral components (13 percent) that required a repeat revision for aseptic loosening. Additionally, there were three stems that were probably loose and one stem that was definitely loose. Patients with type II bone loss were significantly more likely to have a loose component or to require revision (Fishers exact test, p < 0.05). Patients with good bone had less loosening (Mann-Whitney test, p = 0.004).
Using a ranking of A for the best cement technique and C for the poorest technique, researchers found more loosening as the cement technique declined (Spearman correlation, rho = 0.4, p = 0.04). This association of loosening or revision with grade C cement technique increased if the patient additionally had poor bone (correlation rho = 0.7, p = 0.001).
Researchers concluded that alternative reconstructive techniques may need to be employed in patients with Type II bone loss or greater. Cement technique must be emphasized during this recontruction because patients with higher quality (Grade A or B) cement technique achieved better results.
Researchers included Michael George Ryan, MD, of Carlsbad, Calif., and Paul M. Pellicci, MD; Douglas E. Padgett, MD; Thomas P. Sculco, MD; Eduardo Agustin Salvati, MD, and Bryan J. Nestor, MD, all of New York City.
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