Patient-Reported Outcomes and Risk Factors for Decreased Improvement after Patellofemoral Arthroplasty

Abstract

Patellofemoral arthroplasty (PFA) is acknowledged as the method for the treatment of isolated patellofemoral osteoarthritis (PFOA). Few previous studies have assessed the patient-reported outcomes (PROs) and risk factors of less improvement of PROs in patients undergoing PFA. A retrospective analysis was performed, including all patients who had undergone PFA. Pre- and postoperative PROs included the Oxford Knee Score (OKS) and Kujala score. Univariate and multivariate statistical analyses were performed to assess influencing factors of less improvement of PROs including the demographic factors (gender, age, body mass index, smoking, opioid usage, and duration of symptoms [DOSs]), surgical factors (concomitant surgery), and imaging factors (trochlear dysplasia [TD], patellar height, the degree of PFOA). A total of 46 PFAs were analyzed with a mean follow-up of 37 ± 7 months. The mean age at surgery was 61.1 ± 7.7 years. Patients showed significant improvement in all PROs (p < 0.001). Patients with TD preoperatively have greater improvement in OKS and Kujala score postoperatively (19.2 ± 5.0 vs. 23.1 ± 3.6, p = 0.038). Longer DOSs (≥1 year) had a greater mean improvement in OKS and Kujala score (p = 0.011 and p = 0.000). According to the measurement of patella height, patients with patella alta (Caton–Deschamps index [CDI] ≥1.3) showed less improvement in both OKS and Kujala score (p = 0.000 and p = 0.002). PFA is a safe and efficient surgery with good PROs. Patella alta with a CDI ≥1.3 and duration of preoperative symptoms ≤ 1 year were risk factors for decreased OKS and Kujala score improvement, while the preoperative presence of TD was significantly predictive factors for increased OKS improvement.

Modern Patellofemoral Arthroplasty

“…Trochlear dysplasia is inherently addressed with an onlay implant, but the TT-TG or patella height may need to be addressed with a concomitant procedure. The presence of trochlear dysplasia is associated with improved PROMs after PFA 44 . Rotational alignment that is beyond the limits of correction through the anterior femoral cut should be corrected before PFA.…”

“…Better results have been reported in patients with more severe changes on preoperative radiographs, and deDeugd et al advise caution when considering PFA for those with minimal radiographic evidence of PFOA 43 . Preoperative symptoms for less than 1 year were noted as a risk factor for decreased patient-reported outcome measure (PROM) improvement after PFA 44 . Kazarian et al showed that low scores in the mental health section of the 36-Item Short Form questionnaire are associated with a higher postoperative dissatisfaction and lower rate of overall patient satisfaction.…”

“…Similarly, patella alta and trochlear dysplasia are significantly more frequent in PFOA with an increase in both trochlear angle and Dejour score noted by Mofidi et al 47,48 . PFA can reduce patella height; however, this has not been quantified and the effect of patella height on the overall outcome of PFA is uncertain with the literature showing mixed results 44,48-50 . Beckmann et al concluded that patients with patella alta are contraindicated for an inlay design based on their 2019 study showing a high rate of revision for patella clunk after PFA with the inlay HemiCAP Wave implant 51 .…”