Point‐of‐care ultrasound in haemophilic arthropathy: will the HEAD‐US system supplement or replace physical examination?

Over the last decades, the advent of simple-to-use, inexpensive, portable ultrasound devices, with adequate technology to examine both superficial and deep body areas with high-resolution, has boosted the growth of ‘point-of-care’ ultrasound – ultrasound performed and interpreted by the clinician – in a variety of health care settings [1]. A point-of-care ultrasound approach is usually optimized by adopting a focused, decision-making strategy to answer specific clinical questions, or identify relevant biomarkers, without the need for detailed, radiological assessment. Point-ofcare ultrasound is therefore not comparable with a comprehensive ultrasound examination performed by imaging specialists, but rather supports a more time– efficient, straightforward, real-time approach to critical clinical issues that may affect patient management. In the musculoskeletal system, the value of point-ofcare ultrasound is particularly apparent in multi-joint pathologies, where disease detection may be important in otherwise asymptomatic joints, and it may be useful to evaluate or adjust the appropriate treatment strategy. A typical example is rheumatoid arthritis, in which point-of-care ultrasound is successfully used as a screening tool to detect joint effusion, synovial proliferation, bone erosions and soft-tissue injuries as an adjunct to physical examination. For this purpose, approximately a third of rheumatologists currently use ultrasound on a routine basis [2]. Haemophilia is another disease area with potential to benefit from implementation of point-of-care ultrasound for routine joint assessment. The HEAD-US (Haemophilia Early Arthropathy Detection with UltraSound) system has recently been developed for nonimaging specialists, as a fast to perform technique, capable of screening six joints (the elbows, knees and ankles) in a single examination [3]. The HEAD-US system has also been designed to recognize certain biomarkers reflecting disease activity and osteochondral damage [3]. It is proposed that in daily practice, the HEAD-US system would find its place as a supplement to physical examination assessment tools, such as the Haemophilia Joint Health Score (HJHS), in order to provide more objective assessment of findings and increase sensitivity in detecting joint abnormalities. The value and performance of the HEAD-US system in clinical practice is assessed by Foppen and colleagues [4] in their article published in this issue of the journal. For this purpose, the HEAD-US protocol was utilized in a challenging group of 32 children (mean age 11.5 years) free of any history of joint damage (88% of patients with haemophilia A, 94% of which had severe phenotype). Two joints per patient were examined – the joint with the highest risk of arthropathy based on lifetime bleeding history and its contralateral – for a total of 63 joints. A portable ultrasound machine equipped with conventional small-parts probes was used for this purpose. On the same day, clinical function was determined according to the HJHS scale [5]. In this study, a strong correlation (r = 0.70, P < 0.01) was observed between HEAD-US and HJHS. Interestingly, ultrasound showed abnormalities in five joints with a history of bleeds (accounting for approximately 8% of cases), one of which was negative on HJHS assessment [6]. In another three cases, ultrasound examination was normal despite a slight loss of function detected by HJHS examination. Since damaged joints in children present with focal or diffuse cartilage thinning that cannot be quantified by measurements, the arbitrary choice of the authors to scan the contralateral joint as a reference seems appropriate. Nevertheless, the high incidence of unexpected abnormalities detected by point-of-care ultrasound utilizing the HEAD-US system compared with negative or slightly abnormal HJHS (range 1–2 points) would suggest a recommendation to extend HEAD-US screening Correspondence: Carlo Martinoli, MD, Radiologia III DISSAL. Universit a di Genova, Via Pastore 1. I-16132 Genova, Italy. Tel.: +39 3355614449; fax: +39 0105556620; e-mail: carlo.martinoli@libero.it