It remains unclear whether people with traumatic-onset patellofemoral pain (PFPT) present with the same physical and non-physical changes as people with gradual-onset patellofemoral pain (PFPA). In this cross-sectional study, we aimed to compare clinical, biomechanical and muscle strength outcomes between people with PFPT, people with PFPA, pain-free controls with a history of knee trauma (CTRLT), and pain-free controls without a history of knee trauma (CTRLA). Clinical variables included pain-related characteristics, time since knee trauma, kinesiophobia, and functional capacity (e. g. , self-reported, objective). We captured kinematics and kinetics during a single-leg landing task, and maximal isometric torque of the knee extensors and flexors, and the hip abductors using an isokinetic dynamometer. We performed between-group comparisons using generalized linear models and independent t-tests. The PFPT group reported higher pain, greater kinesiophobia, and lower self-reported function compared with the PFPA group. The PFPT group also demonstrated greater peak trunk flexion, greater peak hip flexion, and a lower knee contribution to the total support moment (TSM) compared with the PFPA group. Both the PFPT and PFPA groups demonstrated reduced isometric peak torque of the knee extensors compared with the CTRLT group. The CTRLT group demonstrated higher peak hip flexion, lower knee contribution to TSM, and greater patellofemoral joint stress compared with CTRLA. People with PFPT demonstrated a worse clinical profile and a more hip-dominant landing strategy compared with those with PFPA. Most impairments (e. g. , landing biomechanics and muscle strength) were evident only in comparison with CTRLT, who also differed clinically and mechanically from CTRLA.
Lopes et al. (Wed,) studied this question.