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

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.