Patellofemoral Pain After Knee Trauma: Exploring Clinical, Biomechanical, and Muscle Strength Variables

Area of Science:

• Orthopedics
• Sports Medicine
• Biomechanics

Background:

• Patellofemoral pain (PFP) is common, but differences between traumatic (PFP_T) and gradual-onset (PFP_A) are unclear.
• Understanding these differences is crucial for targeted rehabilitation strategies.

Purpose of the Study:

• To compare clinical, biomechanical, and muscle strength outcomes between PFP_T, PFP_A, and pain-free controls with (CTRL_T) and without (CTRL_A) a history of knee trauma.

Main Methods:

• Cross-sectional study comparing four groups: PFP_T, PFP_A, CTRL_T, CTRL_A.
• Assessed pain, kinesiophobia, function, landing kinematics/kinetics, and isokinetic muscle strength (knee extensors/flexors, hip abductors).

Main Results:

• PFP_T reported higher pain, kinesiophobia, and lower function than PFP_A.
• PFP_T exhibited greater trunk/hip flexion and reduced knee contribution to total support moment (TSM) during landing compared to PFP_A.
• Both PFP groups showed reduced knee extensor strength versus CTRL_T.
• CTRL_T displayed altered landing mechanics and higher patellofemoral stress than CTRL_A.

Conclusions:

• Individuals with PFP_T present with a more severe clinical profile and a hip-dominant landing strategy than those with PFP_A.
• Many biomechanical and strength deficits in PFP patients are only evident when compared to individuals with a history of trauma, highlighting the importance of appropriate control groups.