Objectives To determine the incidence and occupational outcome of overuse anterior knee pain (AKP) in Army recruits undergoing basic training.

Methods A prospective cohort study of 1008 Army recruits. Recruits underwent the 12-week phase 1 training program. Cases of AKP were captured through self-presentation of pain at a primary care medical centre. All recruits medical records were reviewed on leaving training and any other lower limb injuries were recorded for comparison with the AKP group. Training outcomes in terms of medical discharges (MD) and discharges as of right (DAOR) i.e, voluntary discharge, were recorded along with training days lost (TDL) and whether a recruit had been held back in training (BS).

Results 8.75% (95%CI: 6.93 – 10.57) of recruits reported to the medical centre with AKP. Of these more than half were referred to see a GP and the majority were from patients with no previous history of AKP (91%, 95% CI: 85.2 – 97.5). The median TDL per AKP case was 3 days (IQR: 3-5 days). The AKP group had a significantly higher (p<0.01) MD rate (12.5%) than the lower limb injury group (3.3%; 95% CI diff: 1.1 – 17.2% ) and the baseline rate of all other recruits (2.5%; 95% CI diff: 2.3 – 17.7%). The majority of AKP cases occurred by week 4 (median) of training (IQR: 2.2 – 6.4).

Conclusions There was a high incidence of AKP, and while the short term prognosis appears relatively good in the majority of cases as reflected in the median TDL, a large minority were medically discharged and held back in training. Further work should examine methods of reducing the disease burden of AKP in the Army, addressing areas such as aetiology, prevention and treatment.