Ultrasonography of Knee Joint in Hemophilia A: What the Eyes Cannot See

Haemophilia is the most common inherited coagulopathy. Approximately 94% patients suffer from joint disability. An imaging modality to detect joint damage can help in monitoring. Ultrasonography (USG) provides a low cost and reliable imaging alternative to magnetic resonance imaging. This study aims at the detection of subclinical knee-joint involvement by USG, in patients with moderate to severe Haemophilia. 27 patients suffering from moderate and severe Haemophilia and 27 age-matched controls were studied. USG of bilateral knee joints was done to analyse cartilage and synovial thickness, synovial vascularity and resistive index of vascular flow along with synovial collection. The relevant clinical parameters (age at diagnosis and study enrolment, severity of haemophilia A, annualized bleeding rates, total number of joint bleeds, spontaneous and provoked bleed, number of episodes treated with factor VIII injection) were noted. The USG findings were correlated to the clinical parameters and subclinical joint bleed detection looked for. 13 patients [18 out of 54 joints (33.33%)] showed increased vascular signals with mean resistive-index (RI) 0.67 (± 0.086; 95% CI: 0.62-0.70). The mean synovial thickness in persons with haemophilia (PwH) was higher than the control subset (p < 0.05 on all counts). The mean cartilage thickness was lower in PwH than in controls. On a subset analysis, there was significant difference between the mean cartilage thickness between moderate PwH and age matched controls (p < 0.0001). 3 patients (11.1%) showed evidence of joint collection (hemarthrosis) despite having no clinical evidence of joint involvement. Through the findings of our study, we do infer that ultrasonography can detect subclinical synovial inflammation and cartilage damage in haemophilia patients that may affect long term articular outcome. It is also a useful modality for detection of sub clinical joint bleed.