Implications of knee crepitus to the overall clinical presentation of women with and without patellofemoral pain

Abstract

ObjectivesCompare anthropometric characteristics, function, kinesiophobia, catastrophism and knee extensor strength between women (i) with PFP and crepitus (PFPcrepitus); (ii) with PFP and no crepitus (PFPNOcrepitus); (iii) without PFP and crepitus (Pain-freecrepitus); and (iv) without PFP and no crepitus (Pain-freeNOcrepitus). DesignCross-sectional. SettingLaboratory study. Participants65 women with PFP and 51 pain-free women. Main outcome measuresObjective assessment of knee crepitus, forward step-down and single leg hop tests; knee extensor strength tests; and subjective ratings of function, kinesiophobia, pain catastrophising and knee stiffness. ResultsCrepitus was more common in women with PFP (50.7%) compared to those without (33.3%) (χ(1)2=4.17;p=0.031). PFPcrepitus and PFPNOcrepitus groups had lower self-reported function; and higher kinesiophobia, catastrophism and knee stiffness compared to Pain-freecrepitus and Pain-freeNOcrepitus groups (p < 0.001). PFPcrepitus, PFPNOcrepitus and Pain-freecrepitus groups had lower functional performance compared to the Pain-freeNOcrepitus group (p < 0.040). PFPcrepitus and PFPNOcrepitus groups had lower isometric, concentric and eccentric knee extensor strength compared to the Pain-freeNOcrepitus group (p < 0.041), but not the pain-freecrepitus group. PFPcrepitus presented higher BMI than other groups (p = 0.001). ConclusionKinesiophobia, catastrophism, knee stiffness, strength and physical function are all impaired in women with PFP, regardless of crepitus. In pain-free women, crepitus was associated with poorer objective function.