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 (PFP_crepitus); (ii) with PFP and no crepitus (PFP_NOcrepitus); (iii) without PFP and crepitus (Pain-free_crepitus); and (iv) without PFP and no crepitus (Pain-free_NOcrepitus).

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). PFP_crepitus and PFP_NOcrepitus groups had lower self-reported function; and higher kinesiophobia, catastrophism and knee stiffness compared to Pain-free_crepitus and Pain-free_NOcrepitus groups (p < 0.001). PFP_crepitus, PFP_NOcrepitus and Pain-free_crepitus groups had lower functional performance compared to the Pain-free_NOcrepitus group (p < 0.040). PFP_crepitus and PFP_NOcrepitus groups had lower isometric, concentric and eccentric knee extensor strength compared to the Pain-free_NOcrepitus group (p < 0.041), but not the pain-free_crepitus group. PFP_crepitus 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.

Keywords: Function; Kinesiophobia; Knee pain; Strength.