Background: Proponents of minimally invasive total knee arthroplasty claim that patellar eversion and anterior tibial translation during total knee arthroplasty have a deleterious effect on early patient rehabilitation and the early clinical outcome. Our purpose was to identify differences in knee preference and clinical outcome measures in a series of patients who had undergone bilateral total knee arthroplasty with each knee randomized to one of two different surgical approaches: patellar eversion and anterior tibial translation, or patellar subluxation and no tibial translation.
Methods: The knees of forty patients were prospectively randomized to one of two treatment groups, patellar eversion or patellar subluxation, with each patient having one knee treated with each type of approach. Three patients were withdrawn, leaving a final study group of thirty-seven patients. The patients and physical therapists were blinded to the type of treatment. Clinical outcomes, including the Knee Society scores, range of motion, quadriceps strength as tested with a dynamometer, and the patient's preferred knee on the basis of pain, motion, and strength, were collected preoperatively and at six weeks, twelve weeks, and six months postoperatively and were analyzed.
Results: At six weeks after the surgery, there were no significant differences between the two groups with regard to the range of motion, quadriceps strength, or Knee Society scores. With regard to the patient's knee preference at six weeks, the two knees were rated as being the same in terms of pain, whereas a higher percentage preferred the knee treated with eversion in terms of motion (43% compared with 35% who preferred the knee treated with subluxation) and strength (43% compared with 22%). The mean arc of motion in both groups was approximately 113°. At twelve weeks and six months after the surgery, we found no significant differences between the treatment groups in terms of the range of motion, quadriceps strength, or Knee Society scores, and there was no difference with regard to the patient's knee preference.
Conclusions: We found no significant differences between the two treatment groups (patellar eversion and anterior tibial translation compared with patellar subluxation and no tibial translation) at six weeks, twelve weeks, or six months after the surgery. We concluded that patellar eversion and anterior tibial translation appear to have no adverse effects on the range of motion, quadriceps strength, or patient's knee preference during the early postoperative recovery period after total knee arthroplasty.
Level of Evidence: Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence.