Midterm results using a medial pivot total knee replacement compared with the Australian National Joint Replacement...

In order to emulate normal knee kinematics more closely, and thereby potentially improve wear characteristics and implant longevity, the medial pivot-type knee replacement geometry was designed. In the current study the outcome of 50 consecutive knee replacements using a medial pivot-type knee replacement was compared with the results in the Australian Orthopaedic Association National Joint Replacement Registry.

Pre- and post-operatively at follow-up evaluation consisted of the Knee Society score system and the Western Ontario and McMaster Universities Arthritis Index Score. Patient satisfaction was documented using 5-point Likert-type scales. Standard radiographs were used to assess signs of radiographic failure. Revisions were subcategorized into major total, major partial and minor. Patient records were cross-referenced against the Australian Orthopaedic Associations National Joint Replacement Registry's and the outcome compared with the registry's subset of data on the medial pivot knee used.

According to the patients' Knee Society score system and Western Ontario and McMaster Universities Arthritis Index scores, there was good pain relief and functional improvement; none of the implants showed radiographic signs of failure. There was one minor revision. There was no statistically significant difference in revision rate compared with the registry results.

The medial pivot knee-type implant in this series provided pain relief, functional improvement and a revision rate, similar to what is reported in the literature after a longer follow-up period, which is reassuring for those who use this type of implant on a day-to-day basis.