Is anterior knee pain a predisposing factor to patellofemoral osteoarthritis?

Adolescent anterior knee pain has traditionally been described as running a benign and self-limiting course. Studies more recently have questioned this supposition. This study aimed to assess how many patients who had undergone patellofemoral arthroplasty for isolated patellofemoral arthritis had previously suffered from adolescent anterior knee pain, knee instability and trauma. This group was then compared to a control group of medial unicompartmental arthroplasty patients. Both groups were surveyed by postal questionnaire, with a >75% response rate from each group. 22% of the patellofemoral arthroplasty group described adolescent or early adulthood anterior knee pain as compared to 6% in the medial unicompartmental arthroplasty group (p<0.001). Patients in the patellofemoral group had also suffered significantly more patellofemoral instability and trauma than the medial unicompartmental group (p<0.001 and p=0.02, respectively). A significant number of patients with patellofemoral arthritis have described preceding anterior knee pain in their adolescence and early adult years, raising the question as to whether anterior knee pain may be one of the contributing factors to patellofemoral osteoarthritis in later years.