Biomedical subjects

Thomas H McCoy

Publications and source records attributed to Thomas H McCoy.

5 recordsLinked to original sources

PubMed2004

Early morbidity of modular exchange for polyethylene wear and osteolysis.

This study assessed the early morbidity associated with modular component exchange surgery for the treatment of accelerated polyethylene wear and osteolysis in 55 patients. Review of the surgical records revealed no significant intraoperative complications, little intraoperative blood loss (mean 333 mL), no allogenic blood transfusions, and no recorded postoperative deep vein thromboses. Eighteen percent of patients, however, experienced postoperative dislocation. Five patients dislocated multiple times, 3 of which required rerevision surgery. Two patients required rerevision for femoral implant fractures related to osteolysis and 1 additional patient required rerevision due to catastrophic failure of the acetabular component 5 years postoperatively. With an average follow-up of 30 months, 6 of the 55 patients treated with modular exchange required rerevision. The results of this study suggest that instability is the most prevalent early complication associated with modular component exchange. As such, we believe that more stable constructs should be emphasized, possibly at the expense of polyethylene thickness.

Acetabulum↗

PubMed2004

Early osteolysis associated with trunion-liner impingement.

Osteolysis is perhaps the biggest unsolved problem in joint arthroplasty. Many factors contribute to osteolysis, some of which cannot be controlled. It is imperative to minimize controllable factors contributing to osteolysis whenever possible. We report four cases of trunion impingement on an elevated rim liner, which may have contributed to early aggressive osteolysis. Although the use of an elevated liner may result in a lower incidence of postoperative instability, the trade-off in using such a device must be understood.

Adult↗

PubMed2004

Bipolar reconstruction for recurrent instability of the hip.

Between 1986 and 1998, 81 total hip revisions were performed for recurrent instability. Twenty-three revisions were fixed cups to bipolars. Average follow-up was 50 months. Radiographic evaluation showed no significant osteolysis and average migration of 1.7 mm. The average postoperative Harris hip score was 74. All patients who underwent revision to a bipolar prosthesis had no further instability. Acetabular revision to a bipolar prosthesis provides stability in recurrent prosthetic hip instability.

Arthroplasty, Replacement, Hip↗

PubMed2003

Stem fixation in revision total knee arthroplasty: a comparative analysis.

Methods of stem fixation are a controversial aspect of revision TKA. We sought to determine which technique was superior by reviewing 475 revision TKAs done between 1986 and 2000. Of these 475 revisions, 286 major component revisions were done using 484 extended stems for fixation. Patients who died, patients who had less than 2 years follow up, or patients who had diaphyseal engaging stems were excluded from the study. The final data set included 113 revision TKAs with 202 metaphyseal engaging stems. Of the 202 stems, 107 were cemented whereas 95 were press-fit metaphyseal engaging stems. One hundred one of these were femoral stems and 101 were tibial stems. Using a modified Knee Society radiographic scoring system, 100 (93%) of the 107 implants with cemented stems were considered stable, seven (7%) were categorized as possibly loose requiring close followup, and none were loose. Of the 95 implants placed with cementless stems, only 67 (71%) were categorized as stable. Eighteen (19%) were possibly loose requiring close followup and 10 (10%) were loose (two tibial and eight femoral implants). We currently would urge caution in using cementless metaphyseal engaging stems for fixation in revision TKA.

Aged↗

PubMed2002

Polyethylene exchange only for prosthetic knee instability.

From 1987 to 1996, 47 revision total knee arthroplasties were done for tibiofemoral instability. Sixteen of these patients had polyethylene exchange only to treat their instability. Fourteen of these patients were available for review. The mean followup was 56 months. The mean Hospital for Special Surgery Knee Score increased from 50 points preoperatively to 73 points at the most recent followup. Clinically, stable knees were produced in 71% of patients (10 of 14). The results of the current study suggest that polyethylene exchange can be an effective, low morbidity procedure to treat certain types of prosthetic knee instability. A failure rate of 29% (four of 14) however, is concerning. Alternative methods of stabilization should be used, if there is any question concerning the stability of a construct where a polyethylene exchange only is used.

Adult↗