Interim Results of a New Examination Protocol for Women and Girls with Inherited Bleeding Disorders (WGBD)

Women and girls with haemophilia (WGBD), including those who are symptomatic carriers (F VIII/IX plasma levels ≥ 40 IU/ml¹), experience joint haemarthrosis similar in nature to that experienced by men with mild haemophilia.² However, WGBD are often overlooked in both clinical and research settings.^3,4 Current ultrasound techniques are primarily able to detect synovitis, which is a later stage of haemarthrosis.⁵ Inflammatory processes may lead to joint dysfunction even in the absence of structural damage.⁶ Early detection of subclinical joint bleeding is of paramount importance.⁷

We are therefore developing a new assessment protocol for WGBD that combines biomechanical analysis and our new psychometric quality of life questionnaire with the existing diagnostic toolset of the Pictorial Blood Loss Assessment Chart (PBAC), Haemophilia Joint Health Score, ISTH Bleeding Score, Haemophilia Early Arthropathy Detection with Ultrasound (HEAD-US).

In collecting the interim results described in this second abstract, we aimed to determine whether the Noraxon system, using validated inertial measurement units (IMUs) and electromyography (EMG), can facilitate the early detection of joint damage in WGBD using non-invasive gait analysis. A comparison was made between the results of the Noraxon biomechanical analysis and those obtained from PBAC, ISTH bleeding scores, HEAD-US and HJHS measurements in a group of 26 WGWH. Symptomatic participants were asked about any joint complaints.

The mean age of the participants was 38.8 years (range 14-71). Of the participants, 23 had haemophilia A and three had haemophilia B, including seven individuals with combined VWD. As expected, the PBAC score for heavy menstrual bleeding was above 150 (mean 161). There was a positive correlation between HJHS and HEAD-US scores (Pearson correlation coefficient r = 0.595). Interestingly, there is a positive and moderately significant correlation between the ISTH Bleeding Score and HJHS (r = 0.5), but not with HEAD-US.

When patients were asked about joint complaints, a strong correlation was found in bilateral EMG measurements when the gastrocnemius muscle was considered in the stance phase (Pearson correlation coefficient (r = 0.446)). A very high significance was also observed when the recorded ankle complaints were correlated with kinematic measurements of hip abduction (0.002), hip rotation (0.034) and ankle abduction (0.011).

The strong correlations shown in the interim results convinced us that gait and movement analysis is a very powerful tool for early detection of incipient joint and ankle changes in WGBD. Therefore, we are encouraged to a) further develop our new WGBD-Examination-Protocol b) test it on more patients and c) propose to collect and analyze more data nationally and internationally.