Risk Factors for Patellofemoral Pain in Military: A Systematic Review
Knee Joint, Anterior Knee Pain, Relative Risk, Military Force, Naval Medicine.
The main causes for abandonment of military training are musculoskeletal injuries to the knee joint, with patellofemoral pain being one of the most common causes for abandonment of military careers. It has been suggested that the etiology of patellofemoral pain is multifactorial, and that several factors may be associated with a higher risk of developing this condition. However, there is a need for greater knowledge about risk factors for patellofemoral pain, specifically in the military population. The objective of this systematic review is to verify which factors predispose to the occurrence of patellofemoral pain in military personnel. For this review, searches were performed on Medline/PubMed, CINAHL, Embase, SPORTdiscus, Web Of Science and Scopus databases. To be included in this review, studies should have at least one variable evaluating a risk factor for patellofemoral pain and be a prospective cohort including military personnel. Meta-analyses were performed standardized mean differences (SMD) and risk ratio. From 10 articles, this review grouped 7,203 military personnel, of which 535 developed patellofemoral pain, characterizing a prevalence of 7.42%. There is moderate evidence that knee extensor weakness predicts patellofemoral pain, especially if normalized by body mass index and assessed isokinetically at 60º/s (SMD -0.69, CI -1.02, -0.35). We found moderate evidence that sex, body mass index, isometric contraction of the knee extensors and isokinetic strength of the knee flexors do not predict patellofemoral pain. There is strong evidence that age, body mass and age do not predict patellofemoral pain. This systematic review demonstrated that a deficit in knee extensor strength is a predictive factor for patellofemoral pain in military recruits. Intervention strategies should consider this muscle strength deficit for establishing patellofemoral pain prevention approaches in military personnel.