Duration of Initial Activity Restriction for Patellofemoral Pain Syndrome and Probabilities of Return to Activity

Activity restrictions assigned because of patellofemoral pain syndrome (PFPS) among military members is a central component of care for these problems. However, no prior study has assessed the relationship between the parameters of such restrictions and later patient outcomes. The purpose of this study was to identify associations between initial activity restriction durations for PFPS and subsequent return to unrestricted activity.

We studied active duty U.S. Army soldiers who received activity restrictions for PFPS during January 2014 to June 2016 (N = 15,085). Descriptive statistics were organized to support graphic display of the proportions of men and women who returned to activity after selected initial restriction durations. Sex-specific multivariable logistic regression models provided adjusted odds ratios (aORs) for activity return following restrictions.

Activity restrictions 30 to 32 days in duration were most prevalent (n = 5,496; 36.43%). However, the highest adjusted activity return odds were seen for restrictions of 14 to 19 days in duration (men: aOR = 2.00, 95% confidence interval [CI] = 1.73 to 2.32; women: aOR = 2.08, CI = 1.46 to 2.94). Reduced activity return odds were seen in subjects with high body mass index and tobacco use.

Shorter initial restrictions than were most commonly provided were associated with the highest probability of activity return. The findings support the potential for enhanced return to activity rates if shorter restrictions were assigned. However, they indicate the need for prospective research into activity restriction parameters in PFPS to confirm the associations seen.