Sex-specific differences in functional outcomes from anterior knee pain in military personnel
Lilach Gavish, Elad Spitzer, Ilan Friedman, Joseph Lowe, S David Gertz, Arik Eisenkraft, Noam Olshinka, Michael Malkin, Yair BarzilayIntroduction
The incidence of anterior knee pain (AKP) in female military personnel is twice that of their male counterparts. However, whether AKP affects functional outcomes differently in females remains unclear. The objective of this study was to identify differences in AKP-associated functional outcomes between male and female combatants.
Methods
This was a cross-sectional secondary analysis by biological sex (male/female) of active combat soldiers of the Israel Defense Forces and Israel Border Police personnel with AKP due to overuse, using screening data originally collected for a registered interventional study. Outcome measures included Kujala AKP scores by functional domain, anatomical mapping of pain location (by tenderness on palpation) and pain level measured using a Visual Analogue Scale (VAS).
Results
The cohort comprised 27 females, 45 males and 112 knees. Females were younger (20.1 ± 1.3 vs 22.9 ± 6.3 years, p< 0.001), had lower body mass index (23.0 ± 3.2 vs 24.6 ± 3.2 kg/m², p=0.006) and reported less premilitary physical activity (67% vs 89%, p=0.021). In female combatants, tenderness on palpation was more frequent over the patellar ligament (PL) versus the patella (P) itself (PL vs P: females, 59% vs 32%, p=0.016; males, 51% vs 48%, p=0.74). Females reported significantly higher pain levels than males (VAS: 54±23 vs 45±23 mm on scale, p=0.046) and significantly lower overall functionality and symptoms (Kujala: 67±12 vs 73±11, p=0.030). The frequencies of affected performance from AKP were significantly greater in females for running and ascending/descending stairs (running: 30% vs 9%, p=0.022 and stairs: 82% vs 56%, p=0.025, respectively).
Conclusions
Female combatants suffer more from AKP, report higher pain levels and have greater functional disability compared with their male counterparts. This study points to the important need for a sex-specific approach for evaluation of AKP-related functional disabilities in order to optimise treatment protocols and reduce the time to return to active service or performance in physically demanding settings.
Trial registration number