Introduction: The objective of this work was to examine the interrelations of posturographic and surface EMG (SEMG) characteristics of ankle muscles in patients with haemophilia while standing naturally.
Methods: Surface EMG of five bilaterally recorded ankle muscles was conducted in 24 patients with haemophilia (PwH, age: 42 [11] years, mean [SD], 22 A, 2 B, 21 severe, 3 moderate) with median (quartiles) WFH orthopaedic joint score of 30 (20/39) points and 24 non-haemophilic controls (Con, age: 42 [12]). Force plate (IBS) signals were captured simultaneously during bipedal stance with eyes open. Load proportion of the left and right sides as well as heel and forefoot were calculated via four independent pressure transducers. Overall, weight distribution (WD) indices are reported with higher results representing a poorer WD.
Results: Analyses of WD showed large differences between groups (PwH: 10.2 [5.4], Con: 5.2 [2.9], P < 0.001, d = 1.15). After clustering PwH, large effects (P = 0.02, ηp 2 > 0.16) were found for amplitude ratios of the lateral gastrocnemius (LG) muscle. In PwH, the degree of joint alteration of the right lower limb was associated with load proportion of the left side (ρ > 0.64, P = 0.001).
Conclusion: Patients with greater dysbalance showed higher forefoot loads and appeared to compensate their altered joint situations with considerably higher amplitude ratios of LG. Further studies should investigate whether therapeutic interventions could alter postural alignment and muscle activation and how these can influence patients' joint function and symptoms.
Keywords: SEMG; haemophilia; knee; motor control; posture; upright standing.
© 2018 John Wiley & Sons Ltd.