The Effect of Patellar Eversion on Functional Outcomes in Primary Total Knee Arthroplasty

A Randomized, Controlled, Prospective Study Evaluating the Effect of Patellar Eversion on Functional Outcomes in Primary Total Knee Arthroplasty.

Short and long term outcomes of total knee arthroplasty patients surgically exposed with patellar eversion are compared to those patients exposed by laterally retracting the patella. It was hypothesized that there would be no difference.

Background:

Patellar mobilization during total knee arthroplasty (TKA) has been debated, with some proponents of minimally invasive TKA suggesting that laterally retracting, rather than everting the patella may be beneficial. It was our hypothesis that by using randomized, prospective, blinded study methods, there would be no significant difference in clinical outcome measures based solely on eversion of the patella during total knee arthroplasty.

Methods:

After an a priori power analysis was done, 120 primary total knee replacements indicated for degenerative joint disease were included in the study and randomized to one of two patella exposure techniques: lateral retraction or eversion. Collaborating investigators and patients were blinded to randomization.

Inclusion Criteria:

• Patients eligible for study participation included all comers for primary total knee arthroplasty indicated for degenerative joint disease. All operations were performed by three well-established arthroplasty-fellowship-trained orthopaedic surgeons using surgical techniques based on that of a senior surgeon. All implanted devices were cruciate-substituting tricompartmental total knee replacements placed through a medial parapatellar approach. All patients were anaesthetized with spinal anesthesia, received a peri-operative cocktail injection, and had tourniquet times between 0 and 120 minutes. Multi-modal post-operative pain management and accelerated physical therapy were performed as previously described.

Exclusion Criteria:

• Patients were excluded from the study if on the operative side they had undergone prior total knee replacement, prior knee arthrotomy, prior osteotomy at or about the knee, or had preoperative angular deformity greater than 20 degrees.