This study was conducted to assess the results in two subgroups:a) the effect of the PFC Sigma as compared to the PFC total knee replacement in lowering patella lateral release rates and b) the results of severe fixed flexion deformity correction with emphasis on some technical operative details.

Data is collected prospectively on all patients undergoing total knee replacements for an ongoing research programmer. As part of this project, we assessed the patella lateral release rate in 954 knees performed between April 1994 and January 2000.

Lateral release was reached in 55 out of 592 PFC knees compared with 25 out of 362 Sigma knees. The overall lateral release rate was 8.3%.

Using the Chi squared test, there is a statistically significant lower lateral release rate using the Sigma system and the study also demonstrated a low overall lateral release rate in our entire series. The biomechanics of the PFC Sigma system and some operative technical points will be discussed in the talk.

As regards the fixed flexion deformity group data was once again collected prospectively on the Knee Society Scoring form. The results are as follows:

Preoperative flexion deformity > 20 degrees = 53 knees, (Range 20 to 60 degrees),

Preoperative Mean Knee Score = 17.2,

Postoperative flexion deformity < 5 degrees=91%

Postoperative Mean Knee Score = 90.04.

These numbers and results are comparable to other large series and some technical operative details will be discussed in the talk.