The mainstay of patellofemoral pain (PFP) treatment is exercise therapy, often in combination with adjunct treatments such as patient education, orthoses, patella taping and stretching, making the intervention multimodal in nature. The vast majority of randomised controlled trials among patients with PFP have investigated the effect of treatment among adults (>18 years of age). So, while systematic reviews and meta-analyses provide evidence-based recommendations for treating PFP, these recommendations are largely based upon the trials in adults. In the present article, we have summarised the findings on the efficacy of multimodal treatment (predominantly exercise) from the three largest trials concerning patients with PFP, focusing on the long-term success-rate 1 year after receiving multimodal treatment, and with a particular focus on the success rate across the different age groups, including both adolescents, young adults and adults. The results of this paper show that there appears to be a difference in the success rate between adolescents and adults, despite providing similar exercise treatment and having similar exercise compliance. While PFP may present in a similar fashion in adolescence and adults, it may not be the same underlying condition or stage, and different treatments may be required. Collectively, this highlights the importance of increasing our understanding of the underlying pathology, pain mechanisms and why treatment may-or may not-work in adolescents and adults with PFP.