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

Abstract

Objectives: Compare 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). Design: Cross-sectional. Setting: Laboratory study. Participants: 65 women with PFP and 51 pain-free women. Main outcome measures: Objective 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. Results: Crepitus 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). Conclusion: Kinesiophobia, 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.