A RANDOMIZED SINGLE BLINDED CLINICAL TRIAL COMPARING POSTERIOR CRUCIATE RETAINING VS. POSTERIOR CRUCIATE SACRIFICING TOTAL KNEE REPLACEMENTS – RESULTS AFTER TWO YEARS

Abstract

One hundred and ninety patients requiring total knee arthroplasty were randomized to one of two treatments: retaining or sacrificing the posterior cruciate ligament during surgery. Both groups received a Genesis II implant (Smith and Nephew Richards) appropriate to the treatment. Patients were seen preoperatively, at three months, one year, and two years. The end-of-study date is at five years postoperatively. Outcome measures include range of motion, the KSCRS, SF-12, and WOMAC. At two years both groups have shown improvement in pain, function, and stiffness. There is no apparent difference between groups with regard to any outcome measures or complications.

The purpose of this study was to compare retaining vs. sacrificing the posterior cruciate ligament (PCL) in total knee arthroplasty in the patients who satisfy the criteria for a cruciate retaining knee.

Two years after total knee replacement, both groups have improved knee function, less pain, and less knee stiffness. There is no apparent difference between the groups with regards to range of motion, function, or other outcome measures.

Designs of total knee arthoplasty implants, as well as surgical techniques continue to evolve. The role of the PCL in primary total knee arthroplasty remains controversial. Current prosthetic designs have the flexibility to either substitute for a resected PCL or allow preservation of the ligament.

One hundred and ninety patients requiring total knee arthroplasty upon satisfying the criteria for a cruciate retaing arthroplasty were randomized to receive either a posterior cruciate retaining implant or a posterior cruciate sacrificing implant. Surgery was performed following standard procedure with the only difference between groups being the sacrificing or retaining of the PCL. Patients were followed at three months, one year, and two years postoperatively. Outcome measures included range of motion, the Knee Society Clinical Rating Score (KSCRS), SF-12, and Western Ontario and McMaster Osteoarthritis Index (WOMAC).

Early results indicate that both groups are doing equally well with no statistical difference in outcomes at two years. There is a trend toward increased range of motion at six and twelve months in the PCL sacrificing group. A six- degree gain was noted in the sacrificed group as compared to a two degree gain in the intact group.

Funding: Smith and Nephew