The Incidence of Anterior Knee Pain and Crepitation After Total Knee Replacement: A Matched Pair Analysis between Rotating Platform and Fixed Bearing Posterior Stabilized Designs

Persistent pain, especially anterior knee pain, with or without crepitation, has been a persistent complaint after total knee arthroplasty in both rotating platform posterior stabilized (RP-PS) and fixed bearing posterior stabilized (FB-PS) designs. Because PFC Sigma RP-PS and FB-PS designs have identical femoral components, we hypothesized that the incidence of post-operative pain, anterior knee pain, asymptomatic crepitation, painful crepitation, and painful crepitation requiring scar excision is similar in both designs. Between March 2000 and May 2004, 81 near-consecutive RP-PS Total Knee Replacements (TKRs) were matched to 81 FB-PS knees based on gender, age, and body mass index. Radiographic analysis included alignment, fixation, and patellar tilt. Clinical assessments were performed at the time of follow-up using the Knee Society Scores. The incidence of anterior knee pain and crepitation was investigated using a detailed patient administered questionnaire. The incidence of post-operative pain, anterior knee pain, asymptomatic crepitation, and painful crepitation was similar in both groups (20.9 %, 19.7 %, 1.2 %, and 8.6 % in the RP-PS; and 20.9 %, 18.5 %, 0 %, and 6.1 % in the FB-PS, respectively). The severity of painful crepitation was also similar in both groups. None was excruciating. The incidence of painful crepitation requiring scar excision was slightly higher in the RP-PS group (6.1 % versus 2.4 %) but it was not statistically significant. In conclusion, there is a trend of increased incidence of painful crepitation requiring scar excision in the RP-PS TKR, although it was not statistically significant in this study.