Division of Paediatric Neurology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
Theme/Functional Area Occupational Therapy & Physiotherapy, Women's Health and Allied Health Professionals, Karolinska University Hospital, Stockholm, Sweden.
BMC Musculoskelet Disord. 2024 Oct 11;25(1):803. doi: 10.1186/s12891-024-07890-4.
Musculoskeletal alterations causing reduced range of motion of the ankle joint are common in children with cerebral palsy (CP). Objective measurements of passive joint resistance and three-dimensional skeletal muscle volume and muscle architecture can lead to a comprehensive understanding of which factors influence joint range of motion.
To investigate the relation between the passive dorsiflexion of the ankle joint, biomechanical contributing factors to the passive joint resistance, and muscular architectural properties of the triceps surae muscle in children with CP.
In this cross-sectional observational study, 14 children with spastic CP (bilateral: 5, unilateral: 9, Gross Motor Function Classification System (GMFCS) level I:11, II:3) naïve to intramuscular tone reducing treatment, and 14 TD children were included. The passive dorsiflexion of the ankle was measured with a goniometer. Passive joint resistance and related parameters were estimated based on a biomechanical model and measurements using a motorized device, the Neuroflexor. Three-dimensional muscle architecture was quantified with diffusion tensor magnetic resonance imaging (DT-MRI).
In the CP group, the median [min, max] passive dorsiflexion was decreased in the most affected leg (MAL) compared to the less affected leg (LAL) (2.5° [-25°, 20°] vs. 12.5° [5°, 30°], p = 0.001). The stiffness coefficient (Nm/rad) in the MAL was significantly higher in children with CP compared to TD children (7.10 [3.39, 62.00] vs. 2.82 [1.24, 10.46], p = 0.015). Muscle architecture properties did not differ between CP and TD, except for pennation angle in the medial gastrocnemius (MG) of the MAL (CP 17.64° (2.29) vs. TD 21.46° (3.20), p = 0.017). The stiffness coefficient, in the MAL, correlated negatively to passive dorsiflexion (r=-0.638) and pennation angle in medial gastrocnemius (r=-0.964), and the non-linear coefficient (Non-linear 1) correlated negatively to the fascicle length of the medial gastrocnemius (r=-0.857).
This study shows that stiffness of the plantarflexors is related to decreased passive dorsiflexion of the ankle and muscle structure of the MG in high-functioning children with spastic CP. Assessments of how dynamic components as well as microscopic muscle alterations contribute to joint stiffness in the plantarflexors in individuals with CP are warranted.
Retrospectively registered in ClinicalTrials.gov, NCT05447299. Observational study. Study start: 2019-01-15, register date: 2022-07-01.
脑瘫（CP）患儿常出现导致踝关节活动范围减小的肌肉骨骼改变。被动关节阻力的客观测量以及三维骨骼肌肉体积和肌肉结构可以全面了解哪些因素影响关节活动范围。
研究 CP 患儿踝关节被动背屈、影响被动关节阻力的生物力学因素以及比目鱼肌的肌肉结构特性之间的关系。
本横断面观察性研究纳入了 14 名痉挛型 CP 患儿（双侧：5 名，单侧：9 名，粗大运动功能分类系统（GMFCS）水平 I：11 名，II：3 名），均未接受过肌内张力降低治疗，以及 14 名 TD 儿童。使用量角器测量踝关节的被动背屈。基于生物力学模型和使用电动设备 Neuroflexor 的测量，估计被动关节阻力和相关参数。使用扩散张量磁共振成像（DT-MRI）量化三维肌肉结构。
在 CP 组中，与较轻受累侧（LAL）相比，受累程度较重的腿（MAL）的中位[最小，最大]被动背屈度降低（2.5°[-25°，20°]与 12.5°[5°，30°]，p=0.001）。CP 患儿的 MAL 中的刚性系数（Nm/rad）明显高于 TD 儿童（7.10[3.39，62.00]与 2.82[1.24，10.46]，p=0.015）。CP 和 TD 之间的肌肉结构特性没有差异，除了 MAL 中的内侧比目鱼肌（MG）的旋前角（CP 17.64°（2.29）与 TD 21.46°（3.20），p=0.017）。MAL 中的刚性系数与被动背屈（r=-0.638）和内侧比目鱼肌的旋前角（r=-0.964）呈负相关，非线性系数（非线性 1）与内侧比目鱼肌的肌束长度呈负相关（r=-0.857）。
本研究表明，高功能痉挛型 CP 患儿的跖屈肌僵硬与踝关节被动背屈和 MG 肌肉结构降低有关。需要评估动态成分以及微观肌肉改变如何对 CP 个体的跖屈肌关节僵硬产生影响。
在 ClinicalTrials.gov 中进行回顾性注册，NCT05447299。观察性研究。研究开始：2019-01-15，注册日期：2022-07-01。
