[Age-related activation of the muscles during upright standing in patients with haemophilia]. / Altersabhängige Ansteuerung der Muskulatur im Stand bei Patienten mit Hämophilie.

Thehaemophilicarthropathyaffects thefunction of theknee joint muscles. The aim of thisstudywas to investigatethe myoelectrical signal ofknee jointmusclesin different agestages during upright standing. Surface EMG (SEMG) amplitudes of quadriceps, hamstrings and gastrocnemii were measured in 191 patients with severe haemophilia A (n=164) and B (n=27) while standing on an even surface. After an age-based classification of patients into the subgroups H(A): 17-29 (n = 37), H(B): 30-39 (n = 50), HC: 40-49 (n = 61), H(D): 50-70 in years (n = 43) the clinical WFH score for the ankle and knee joint was determined. To normalize the SEMG values amplitude ratios (percentage of cumulated activity) were calculated with respect to the specific limb. With increasing age, the patient showed descriptively a deterioration of the joint situation. The extensors of the knee joint reached significantly higher absolute and percentage levels in the muscle activity with increasing age (p < 0.05). The absolute amplitude values of the Mm. gastrocnemii showed no differences in the age groups while the relative levels were decreased. The present study shows that patients with increasing age and degree of haemophilic arthropathy develop a modified control strategy during upright standing, in the form of a shift from the plantar flexors to the extensors of the knee joint.

Impact of joint status on contraction steadiness of m. quadriceps femoris in people with severe haemophilia.

Impaired contraction steadiness of lower limb muscles affects functional performance and may increase injury risk. We hypothesize that haemophilic arthropathy of the knee and the strength status of quadriceps are relevant factors which compromise a steady contraction. This study addresses the questions if impaired steadiness of the quadriceps is verifiable in people with haemophilia (PWH) and whether a connection between the status of the knee joint and quadriceps strength exists. A total of 157 PWH and 85 controls (C) performed a strength test with a knee extensor device to evaluate their bilateral and unilateral maximal quadriceps strength and steadiness. Isometric steadiness was measured by the coefficient of variation of maximum peak torque (CV-MVIC in %). For classification of the knee joint status the World Federation of Haemophilia (WFH) score was used. Lower steadiness (higher CV values) was found in PWH compared with C during bilateral [PWH vs. C; 0.63 (0.36/1.13) vs. 0.35 (0.15/0.72), median (Q25/Q75) P < 0.001] and unilateral trials [left leg: 0.70 (0.32/1.64) vs. 0.50 (0.23/1.04), P < 0.05; right leg: 0.68 (0.29/1.51) vs. 0.39 (0.18/0.68), P < 0.001]. PWH with a WFH score difference (≥1) between their extremities showed a less steady contraction in the more affected extremity (P < 0.05). More unsteady contractions have also been found in extremities with lower quadriceps strength compared with the contralateral stronger extremities (P < 0.001), whereby the weaker extremities were associated with a worse joint status (P < 0.001). The results of this study verify an impaired ability to realize a steady contraction of quadriceps in PWH and the influence of joint damage and strength on its manifestation.

Quadriceps strength, inter-extremity difference (IED) and joint status in adult persons with severe haemophilia in different age stages.

Quadriceps weakness seems to be a hallmark in adult persons with severe haemophilia (PWH). The purpose of this study was to compare PWH and non-haemophilic controls in different age stages with reference to joint status and quadriceps strength. Further aims were to examine the extent of strength-specific inter-extremity-difference (IED) and the prevalence of abnormal IED (AIED). A total of 106 adults with severe haemophilia (H) and 80 controls (C) had undergone an orthopaedic examination for classification of knee and ankle status using the WFH score. Quadriceps strength was evaluated unilaterally as well as bilaterally with a knee extensor device. Each group was divided into four age-related subgroups (HA/CA: 18-29, HB/CB: 30-39, HC/CC: 40-49, HD/CD: 50-70; in years). H presented a worse knee and ankle status than C indicated by higher WFH scores (P < 0.01). Regarding the age-matched subgroups only HB showed higher knee scores than CB (P < 0.05). The ankles were clinically more affected in HB-HD compared with those in age-matched controls (P < 0.05). H showed lower quadriceps strength than C (P < 0.05). In addition, all subgroups of H presented lower strength (HA: 10-17, HB: 19-23, HC: 35-36, HD: 53-61; in%, P < 0.05). IED was higher in H than in C [H: 12.0 (5.3/32.2) vs. C: 7.1 (2.9/10.9); Median (quartiles) in%, P < 0.001] and increased with age in H. We discovered an AIED in 35% of H. These findings highlight the importance for the early implementation of preventive and rehabilitative muscle training programmes in the comprehensive treatment of PWH.