Patient pain drawing is a valuable instrument in assessing the causes of exercise-induced leg pain.

Aim: We validated patientpain drawing (PPD) in establishing the diagnosis of chronic anterior compartment syndrome (CACS) in patients with exercise-induced leg pain.

Methods: The study comprised 477 consecutive patients, all suspected of having CACS. The diagnosis was based on the patient's history, a thorough clinical examination and measurements of intramuscular pressure (IMP) following an exercise test. Patients completed a PPD before their hospital visit. Two independent orthopaedic surgeons diagnosed the causes of leg pain based only on the PPD at least 1 year after admission. Based on the results of diagnostic tests, the patients were divided into three groups: CACS (n=79), CACS with comorbidity (n=89) and non-CACS (n=306).

Results: The sensitivity of the PPD to identify CACS correctly was 67% (observer 1) and 75% (observer 2). The specificity was 65% and 54%, respectively. The interobserver agreement (n=477) was 80%, and the kappa value was 0.55. The interobserver agreement was 77%, and the kappa value was 0.48 among 168 CACS patients with or without comorbidity. The interobserver agreement was 85%, and the kappa value was 0.56 in 79 CACS, and CACS was correctly diagnosed in 79% (observer 1) and 82% (observer 2). The test-retest showed the same results for the two observers, with an intraobserver agreement of 84%, while the test-retest reliability coefficient was 0.7. Comorbidity was found in 53% of CACS patients.

Conclusion: PPD might be a valuable instrument in diagnosing the causes of exercise-induced leg pain. It is useful in identifying CACS with and without comorbidity.