96. MINIMAL INCISION SURGERY AS A RISK FACTOR FOR EARLY FAILURE OF TOTAL KNEE ARTHROPLASTY

Abstract

Purpose: A study was undertaken to determine the current prevalence of revisions of total knee arthroplasty (TKA) following minimal incision surgery (MIS) and to compare revisions of MIS TKA procedures to revisions of TKA performed following a standard surgical approach.

Method: A consecutive series of revision TKA performed at three centers by five surgeons over a three year time period was reviewed. Revisions performed for infection and re-revisions were excluded. Review of clinical and radiographic data determined incision type, gender, age, time to revision, and primary diagnosis at time of revision.

Results: Two hundred and thirty-seven first time revision TKAs were performed of which 44 (18.6%) had been a MIS primary TKA and 193 (81.4%) had been a standard primary TKA. Patients with MIS were younger (62.1 years versus 66.2 years, p=.02). There was a trend towards a higher percentage of females in the MIS group (75% versus 63%), although this difference was not significant (p=0.12). Most striking was the difference in time to revision which was significantly shorter for the MIS group (14.8 months versus 80 months, p< .001). The MIS group was much more likely to fail at < 12 months (37% versus 5%, p< .001) and at < 24 months (81% versus 22%, p< .001).

Conclusion: MIS TKA accounted for a substantial percentage of revision TKA in recent years at these centers. The high prevalence of MIS failures occurring within 24 months is disturbing and warrants further investigation.