Evaluation of anterior knee pain in a PS total knee arthroplasty: the role of patella-friendly femoral component and patellar size.

BACKGROUND: Total knee arthroplasty gives excellent objective results. Nevertheless, the subjective findings do not match the normal knee perception: Often, it depends on patellar pain onset. In this study, we analyzed clinical and radiological items that can affect resurfaced patellar tracking, and role of a patella-friendly femoral component and patellar size on patellar pain onset. MATERIALS AND METHODS: Thirty consecutive patients were implanted using the same-cemented posterior-stabilized TKA associated with patella resurfacing. Fifteen patients were implanted using a classical femoral component, while another 15 patients were implanted using a patella-friendly femoral component. The statistical analysis was set to detect a significant difference (p < 0.05) in clinical and radiological outcomes related to several surgical parameters. Clinical and functional outcomes were recorded using the Knee Society Scoring System (KSS) and patellar pain with the Burnett questionnaire. RESULTS: Mean follow-up was 25 months. KSS results were excellent in both groups. Group 2 (patella-friendly femoral model) reached a higher percentage of 100 points in the clinical and functional KSS, but there was no statistical difference. Also, no statistical differences for Burnett Questionnaire results were recorded. We had one case of patellar clunk syndrome in the standard femoral component group and one poor result in the second group. Postoperative radiographic measurements evidenced no statistical differences in both groups. In group 1 (classical femoral component), better significant result (p < 0.05) war recorded at clinical evaluation according to the Knee Society Scoring System (KSS) in case of wider patellar component resurfaced. CONCLUSIONS: The present study reveals no statistically significant difference in the incidence of anterior knee pain between classical and "patella-friendly" femoral components. With the particular type of implant design utilized in this study, when the classical femoral component is used, bigger patellar implant sizes (38 and 41 mm) showed superior clinical outcome.

Cemented fixed-bearing PFC total knee arthroplasty: survival and failure analysis at 12-17 years.

BACKGROUND: Total knee arthroplasty (TKA) is the appropriate treatment for degenerative pathology of the knee. Implant surveillance is mandatory to improve clinical results. We present the long-term results of a series of consecutive TKA Press Fit Condylar (J&J), cemented fixed bearing with selective patellar resurfacing in nonselected patients. MATERIALS AND METHODS: In this prospective case series, 223 TKA were clinically and radiographically evaluated using the Hospital for Special Surgery (HSS) knee score and the Knee Society Roentgenographic Evaluation and Scoring System. RESULTS: There were 197 patients, with an average age of 68.4 years [95% confidence interval (CI) 52.7-84.1 years]; 49 arthroplasties were implanted in men (21.1%) and 184 (78.9%) in women. The average follow-up was approximately 13.5 years (162.1 months; 95% CI 132.3-191.9), and it was possible to evaluate 179 implants (76.8% of the implanted prosthesis) in 176 patients. The average HSS score increased from 61.5 (95% CI 60.4-62.7) to 89.4 (95% CI 87.7-.93.5) points. The cumulative average survival rate at 15 years (the endpoint being failure with revision) was 90.6%  ± 2% standard deviation. Resurfacing the patella did not make a difference in terms of implant survival. Progressive radiolucent lines were observed around 20 implants (14.3%); all were revised. CONCLUSIONS: The PFC system is an excellent prosthetic solution. Early clinical complications, mechanical axis and patellar resurfacing do not correlate with implant failure, whereas progressive radiolucent lines do.