Summary

PFR patients had a higher total physical activity and step count compared to TKR patients, however the sample was not large enough to detect a significant difference.

Abstract

Background

Patellofemoral joint replacements and total knee replacements have been advocated for patients with isolated patellofemoral joint osteoarthritis. Although patient-reported outcomes have shown to be in favour of patellofemoral joint replacement in the first six months, this discrepancy decreases with time. The purpose of this study was to compare total physical activity, total step count and different types of activity among patients who had had TKRs or PFRs in a randomised controlled trial, 10 years after surgery. Both groups were tested on their ability to adhere to the World Health Organisation's 2020 physical activity guidelines.

Methods

Patients who had isolated patellofemoral joint osteoarthritis in which conservative management failed were recruited to a randomised control trial, who were randomised 1:1 to PFA or TKA between 2007 and 2014. Patients were invited back to participate 10 years later. Those who accepted had a GENEActiv wrist worn accelerometer posted out to them. The patients were told to wear their device all times. The authors removed the accelerometer in the clinical setting after 7 days of monitoring. Data was processed using the GGIR R-Package(http://cran.r-project.org). The duration of inactivity, light, moderate, and vigorous activity was compared between groups. The total physical activity, total step count, and 24-hour ENMO acceleration were measured and compared using T-tests or Wilcoxcon tests based on normality tests.

Results

There were a total of 30 patients recruited as part of the study, 17 patients had a PFR and 13 patients had a TKR. PFR patients did more minutes of total physical activity, 1276.3 minutes per week, compared to TKR patients, 1250.7 minutes per week, although there was no significant difference, p=0.89. PFR patients had a higher step count, 403158 steps per week, compared to TKR patients, 36986.4 steps per week, but p > 0.05. There was no statistically significant difference between the duration of light, moderate and vigorous activity performed. All patients in this cohort met the World Health Organisation 2020 physical activity guidelines.

Conclusion

Although there was no significiant difference between both procedures, PFR patients had a higher step count and total physical activity compared to TKR patients.