Publications
Biomechanical and Viscoelastic Properties of the Ankle Muscles in Relation to Muscle Force in Patients with Operated Tibial Pilon Fractures
Authors: Andrei-Daniel Bolovan 1, 2, Roxana-Ramona Onofrei 2, Gheorghe-Bogdan Hogea 3, 4, 5, Ahmed Abu-Awwad 3, 4, 5, Jenel-Marian Patrascu, Jr. 3, 4, 5, Alexandra-Roxana Tapardea 1, Alexandru-Florian Crisan 2, 6, Elena-Constanta Amaricai 2
Affiliations:
- Doctoral School, Victor Babes University of Medicine and Pharmacy Timisoara, 300041 Timisoara, Romania
- Research Center for Assessment of Human Motion, Functionality and Disability, Department of Rehabilitation, Physical Medicine and Rheumatology, Victor Babes University of Medicine and Pharmacy Timisoara, 300041 Timisoara, Romania
- Department of Orthopedics and Traumatology, Victor Babes University of Medicine and Pharmacy Timisoara, 300041 Timisoara, Romania
- Pius Brinzeu Emergency Clinical County Hospital, Bld Liviu Rebreanu, No. 156, 300723 Timisoara, Romania
- Research Center Teodor Sora, Department of Orthopedics II, Victor Babes University of Medicine and Pharmacy Timisoara, Eftimie Murgu Square, No. 2, 300041 Timisoara, Romania
- Pulmonary Rehabilitation Center, Clinical Hospital of Infectious Diseases and Pulmonology, Victor Babes, 300310 Timisoara, Romania
Journal: Journal of Clinical Medicine - April 2026, Volume 15, Issue 8, Article no. 2934 (DOI: 10.3390/jcm15082934)
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Field & Applications:
- Medical
- Treatment evaluation
- Orthopedics
- Recovery from injury
- Muscle symmetry
Background: Tibial pilon fractures are complex injuries frequently associated with persistent functional impairment, even after successful surgical fixation. While previous studies have reported deficits in muscle strength and balance, little is known about the side-to-side variations in intrinsic biomechanical and viscoelastic muscle properties following surgery.
Objectives: This study aimed to compare the biomechanical and viscoelastic properties of ankle periarticular muscles between the affected and non-affected limbs in patients with surgically treated unilateral tibial pilon fractures. A secondary objective was to evaluate the relationship between intrinsic muscle properties and isometric muscle force.
Methods: A total of 39 subjects with unilateral surgically treated tibial pilon fractures were evaluated after fracture healing. Myotonometric assessment was performed to evaluate muscle mechanical parameters, including tone (frequency), stiffness, and elasticity (decrement), as well as viscoelastic properties, including relaxation time and creep, in the tibialis anterior, peroneus longus, medial gastrocnemius, and lateral gastrocnemius muscles. Isometric muscle force of ankle dorsiflexors and plantar flexors was measured using a handheld dynamometer. Side-to-side comparisons and Pearson correlation analyses were performed.
Results: The affected limb showed significantly reduced ankle range of motion in all planes and significantly lower isometric muscle force in both the dorsiflexors (p = 0.0002) and the plantar flexors (p = 0.0066). Stiffness was significantly higher in the medial (p = 0.038) and lateral gastrocnemius (p = 0.045) muscles on the affected side. Decrement was significantly increased (indicating reduced elasticity) in the peroneus longus (p = 0.021). No significant differences were observed for tone, relaxation time, or creep.
Conclusions: Myotonometry revealed increased stiffness in the gastrocnemius muscles and reduced elasticity in the peroneus longus on the operated side compared with the non-affected limb. Tone and viscoelastic properties did not differ significantly between sides. However, tone, stiffness, and elasticity were significantly correlated with muscle force, indicating a relationship between intrinsic muscle mechanical properties and force production after tibial pilon fracture surgery.
Keywords: tibial pilon fracture, muscle stiffness, viscoelastic muscle properties, stress relaxation time, isometric muscle strength, ankle biomechanics, muscle–force relationship
Myotonometry revealed heightened stiffness and mechanical stress relaxation time with concurrent lowered tone and elasticity of the anterior tibialis, longus peroneus, medial and lateral gastrocnemius muscles of the side with the operated tibial pilon fracture in comparison to the non-affected side. Tone, stiffness, and elasticity of the anterior tibialis and medial and lateral gastrocnemius were directly correlated with the isometric muscle force of dorsiflexors and plantar flexors, respectively.