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CURRENT CONCEPTS

Patellofemoral Disorders:

Are They a Female Issue?

Elizabeth A. Arendt, MD
Minneapolis, MN, USA

Patellofemoral (PF) injury and disease are commonly thought

to be more prevalent in females. Literature to support this
conclusion is sparse. This article investigates possible sex

differences in three categories of PF disorders: PF pain,
patella dislocations, and (isolated) PF arthritis.

Patellofemoral Pain/Anterior Knee Pain

Is anterior knee pain (AKP) more common in females? One

study investigated constitutional features such as sex, age,
body composition, athletic activity and duration of symptoms
as possible predictive factors in the outcome of non-

operative management of AKP. Results did not show sex as
a determinant for AKP. Younger age was the only predictive

factor for favorable outcomes.

A two-year prospective study evaluated motor performance,
joint laxity, limb alignment and muscle flexibility of physical
education students with no prior history of knee problems. Of

the 282 students assessed (151 M/131F; average age, 18.6
years), AKP developed in 7% of the males and 10% of the 02

females. DeHaven and Litner reported on college-age athletes Differences in muscle development between males and
presenting to the training room over a 7-year period; PF pain females are well known, with females having less muscle mass,

was reported in 18.1% of males and 33.2% of females.
different muscle fiber composition and differences in muscle
stiffness about the knee. Testosterone increases muscle
An established link exists between PF pain and clinical
fiber mass, fiber recruitment and type 2 fiber development.
overload. Dye and associates4 have advanced a pain theory Muscle stability also shows variances between the sexes;
centering on biological load acceptance, i.e. PF pain reflects
joint load is influenced by muscle strength and fatigue. These
the loss of tissue homeostasis, i.e., biological tissue exceeding neuromuscular differences between males and females,
load acceptance capacity. With this model, the role of
particularly manifest after puberty, may explain discrepancies
motor control and strengthening in reducing pain is better in the rates of PF pain and injury. Males may have an
understood.
advantage in regard to knee stability, strengthening of knee

musculature, and by association, may be less prone to AKP.

Another consideration is pain perception; females are more
sensitive to pain and have different physical responses to

pain than males. In experimental settings, females are more
sensitive to pain stimuli, less tolerant of pain, and more able to

discriminate between different pain pathways. Several studies
suggest a sex difference in pain perception. Males tolerate

more pain than females in experimental settings. High ‘male-
identifying’ men tolerate more pain than high and low ‘female-

identifying’ women. However, low male identifying men are
equal to women. This highlights the roles of sex and gender
norms in pain-reporting behaviors.

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28 ISAKOS NEWSLETTER 2013: Volume II