Joint Awareness after Patellofemoral Arthroplasty Evaluated with the Forgotten Joint Score: A Comparison Study

Abstract

Objective The aim of the present study was to compare the forgotten joint score (FJS) in patients with isolated patellofemoral osteoarthritis who underwent patellofemoral arthroplasty (PFA) versus those who underwent total knee arthroplasty (TKA) and to analyze the predictors of the FJS after PFA. Methods From January 2014 to December 2017, a retrospective cohort study of 56 consecutive patients with isolated patellofemoral osteoarthritis underwent PFA and were included in the PFA group. The patients in the PFA group were matched in a 1:1 ratio based on age, sex, body mass index (BMI), and follow‐up duration; 56 patients with isolated patellofemoral osteoarthritis underwent cruciate‐retaining TKA (TKA group). The FJS, range of motion of the knee, and Knee Society Score were assessed at 1 and 3 years postoperatively. In addition, the associations between the potential influencing factors (age, sex, BMI, and preoperative Iwano score of the patellofemoral joint) and the FJS were analyzed using multiple linear regression in the PFA group. Results There were no significant differences between the PFA and TKA groups regarding age (P = 0.316), sex (P = 0.832), BMI (P = 0.447), and follow‐up duration (P = 0.625). Postoperatively, the range of motion of the knee and Knee Society Score was significantly higher in the PFA group than the TKA group at both follow‐up points (P < 0.05). The PFA group had a significantly higher mean FJS than the TKA group at 1 year postoperatively (62.9 ± 12.3 vs 54.1 ± 14.2, P = 0.034) and 3 years postoperatively (63.3 ± 14.1 vs 55.6 ± 16.4, P = 0.042). In the PFA group, multiple linear regression analysis showed that older age was positively correlated with the FJS, while a higher BMI was negatively correlated with the FJS. Conclusion The patients with isolated patellofemoral osteoarthritis who underwent PFA were more likely to forget the artificial joint and, consequently, may experience a higher degree of satisfaction. In addition, we identified two preoperative patient‐related factors (age and BMI) that may predict the FJS after PFA, which might help in chosing the most appropriate operation.

Modern Patellofemoral Arthroplasty

“…Two systematic reviews also found similar PROM scores between second-generation PFA and TKA 71,72 . However, some individual studies have shown higher postoperative PROMs and range of motion with PFA when compared to TKA, 73 including a randomized controlled trial by Odgaard et al in 2018 74 . With a sample size of 100 patients randomized to TKA or PFA, they found higher PROMs, better range of motion, and better overall quality of life in the PFA group.…”

Patellofemoral arthroplasty in combination with high tibial osteotomy can achieve good outcome for patients with medial-patellofemoral osteoarthritis

“…FJS can measure a patients' ability to forget joint awareness in daily life. Lin et al reported that patients who underwent PFA had a significantly higher FJS than those who underwent TKA ( 44 ). The average FJS was 71.2 ± 10.2 in our study at the last follow-up, indicating that the patient had been able to forget joint awareness.…”

Anterior Knee Pain: State of the Art

“…Patellofemoral arthroplasty may become necessary, particularly in elderly patients, with advanced patellofemoral arthritis and gross destruction of the joint [ 40 ] (Fig. 8 ).…”