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Khair RM, Stenroth L, Cronin NJ, Ponkilainen V, Reito A, Finni T. Exploration of muscle-tendon biomechanics one year after Achilles tendon rupture and the compensatory role of flexor hallucis longus. J Biomech 2023; 152:111586. [PMID: 37080080 DOI: 10.1016/j.jbiomech.2023.111586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/30/2023] [Accepted: 04/10/2023] [Indexed: 04/22/2023]
Abstract
Achilles tendon (AT) rupture leads to long-term structural and functional impairments. Currently, the predictors of good recovery after rupture are poorly known. Thus, we aimed to explore the interconnections between structural, mechanical, and neuromuscular parameters and their associations with factors that could explain good recovery in patients with non-surgically treated AT rupture. A total of 35 patients with unilateral rupture (6 females) participated in this study. Muscle-tendon structural, mechanical, and neuromuscular parameters were measured 1-year after rupture. Interconnections between the inter-limb differences (Δ) were explored using partial correlations, followed by multivariable linear regression to find associations between the measured factors and the following markers that indicate good recovery: 1) tendon length, 2) tendon non-uniform displacement, and 3) flexor hallucis longus (FHL) normalized EMG amplitude difference between limbs. Δmedial gastrocnemius (MG) (β = -0.12, p = 0.007) and Δlateral gastrocnemius (β = -0.086, p = 0.030) subtendon lengths were associated with MG tendon Δstiffness. MG (β = 11.56, p = 0.003) and soleus (β = 2.18, p = 0.040) Δsubtendon lengths explained 48 % of variance in FHL EMG amplitude. Regression models for tendon length and non-uniform displacement were not significant. Smaller inter-limb differences in Achilles subtendon lengths were associated with smaller differences in the AT stiffness between limbs, and a smaller contribution of FHL muscle to the plantarflexion torque. In the injured limb, the increased contribution of FHL appears to partially counteract a smaller contribution from MG due to the elongated tendon, however the role of FHL should not be emphasized during rehabilitation to allow recovery of the TS muscles.
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Affiliation(s)
- Ra'ad M Khair
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland.
| | - Lauri Stenroth
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Neil J Cronin
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland; School of Sport and Exercise, University of Gloucestershire, UK
| | | | - Aleksi Reito
- Central Finland Central Hospital Nova, Jyväskylä, Finland
| | - Taija Finni
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland
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Altered Ankle Muscle Activation at 2-Year Post Achilles Tendon Repair: An Age, Gender, and Activity Level-Matched Comparison With Healthy Subjects. J Sport Rehabil 2023; 32:305-314. [PMID: 36623511 DOI: 10.1123/jsr.2022-0064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 10/31/2022] [Accepted: 11/07/2022] [Indexed: 01/11/2023]
Abstract
CONTEXT The study purpose was to compare the ankle muscle activation and dynamic ankle joint stability of subjects who underwent endoscopy-assisted Achilles tendon repair (ATR; at ≥ 2 y postsurgery) with age, gender, and activity level-matched healthy control group subjects. DESIGN Prospective, cross-sectional study. All functional tests were performed on the involved ankle of the ATR group, and at the matched side of healthy age, gender, and activity-level control group subjects. METHODS Fifteen men in each group were evaluated for medial and lateral gastrocnemius, soleus, tibialis anterior, and peroneus longus muscle activation during modified star excursion balance test and heel-rise test performance. The weight-bearing lunge test (ankle dorsiflexion) and heel-rise test distance (ankle plantar flexion) also determined weight-bearing, active ankle mobility magnitudes. The Achilles Tendon Total Rupture Score and Foot and Ankle Outcome Score provided patient-reported outcome perceptions specific to Achilles tendon rupture and comprehensive foot and ankle symptoms and function, respectively. RESULTS Medial (P = .005) and lateral (P = .012) gastrocnemius displayed greater activation amplitudes in the ATR group during the star excursion balance test, and peroneus longus displayed greater activation amplitudes during the heel-rise test (P = .006). The star excursion balance test reach distance was comparable between groups. Active weight-bearing ankle plantar flexion (heel-rise test) and dorsiflexion (weight-bearing lunge test) mobility magnitudes were lower in the ATR group. CONCLUSIONS Subjects who underwent endoscopy-assisted percutaneous ATR had reduced active weight-bearing ankle dorsiflexion and plantar flexion mobility magnitudes and greater gastrocnemius and peroneus longus neuromuscular activation when performing the same tasks as healthy control group subjects. As surgical approaches evolve to less invasive, soft tissue preserving methods with less tissue morbidity and faster healing, rehabilitation approaches may likewise need to evolve. LEVEL OF EVIDENCE Level III.
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Distal overactivation of gastrocnemius medialis in persistent plantarflexion weakness following Achilles tendon repair. J Biomech 2023; 148:111459. [PMID: 36738627 DOI: 10.1016/j.jbiomech.2023.111459] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 01/09/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023]
Abstract
Structural alterations of the triceps surae and Achilles tendon (AT) can promote plantarflexion weakness one-year following an AT repair, influencing the activation strategies of the Gastrocnemius Medialis (GM) muscle. However, this is yet to be demonstrated. We aimed to determine whether patients with plantar flexion weakness one-year after AT repair show altered GM spatial activation. In this cross-sectional and case-control study, ten middle-aged men (age 34 ± 7 years old, and 12.9 ± 1.1 months post-surgery) with a high AT total rupture score who attended conventional physiotherapy for six months after surgery, and ten healthy control men (age 28 ± 9 years old), performed maximal and submaximal (40, 60 and 90%) voluntary isometric plantarflexion contractions on a dynamometer. The peak plantar flexor torque was determined by isokinetic dynamometry and the GM neuromuscular activation was measured with a linear surface-electromyography (EMG) array. Overall EMG activation (averaged channels) increased when the muscle contraction levels increased for both groups. EMG spatial analysis in AT repaired group showed an increased activation located distally at 85-99%, 75-97%, and 79-97% of the electrode array length for 40%, 60%, and 90% of the maximal voluntary isometric contractions, respectively. In conclusion, patients with persistent plantar flexion weakness after AT rupture showed higher distal overactivation in GM.
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Khair RM, Stenroth L, Cronin NJ, Reito A, Paloneva J, Finni T. In vivo localised gastrocnemius subtendon representation within the healthy and ruptured human Achilles tendon. J Appl Physiol (1985) 2022; 133:11-19. [PMID: 35546126 DOI: 10.1152/japplphysiol.00084.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Achilles tendon (AT) is composed of three distinct in-series elastic subtendons, arising from different muscles in the triceps surae. Independent activation of any of these muscles is thought to induce sliding between the adjacent AT subtendons. We aimed to investigate displacement patterns during voluntary contraction (VOL) and selective transcutaneous stimulation of medial (MGstim) and lateral (LGstim) gastrocnemius between ruptured and healthy tendons, and to examine the representative areas of AT subtendons. Twenty-eight patients with unilateral AT rupture performed bilateral VOL at 30% of the maximal isometric un-injured plantarflexion torque. AT displacement was analysed from sagittal B-mode ultrasonography images during VOL, MGstim and LGstim. Three-way ANOVA revealed a significant two-way interaction of contraction type*location on the tendon displacement (F(10-815)=3.72, p<0.001). The subsequent two-way analysis revealed a significant contraction type*location interaction for tendon displacement (F(10-410)=3.79, p<0.001) in the un-injured limb only, where LGstim displacement pattern was significantly different from MGstim (p=0.008) and VOL (p=0.005). When comparing contraction types between limbs the there were no difference in the displacement patterns, but displacement amplitudes differed. There was no significant difference in the location of maximum or minimum displacement between limbs. The displacement pattern was not different in non-surgically treated compared to un-injured tendons one-year post rupture. Our results suggest that near the calcaneus, LG subtendon is located in the most anterior region adjacent to medial gastrocnemius. However, free tendon stiffness seems to be lower in the injured AT, leading to more displacement during electrically-induced contractions compared to the un-injured.
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Affiliation(s)
- Raad M Khair
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland
| | - Lauri Stenroth
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Neil J Cronin
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland.,School of Sport and Exercise, University of Gloucestershire, United Kingdom
| | - Aleksi Reito
- Central Finland Health Care District, Finland and University of Eastern Finland, Finland
| | - Juha Paloneva
- Central Finland Health Care District, Finland and University of Eastern Finland, Finland
| | - Taija Finni
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland
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Finni T, Peter A, Khair R, Cronin NJ. Tendon length estimates are influenced by tracking location. Eur J Appl Physiol 2022; 122:1857-1862. [PMID: 35522277 PMCID: PMC9287240 DOI: 10.1007/s00421-022-04958-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/19/2022] [Indexed: 12/01/2022]
Abstract
PURPOSE Measurement of medial gastrocnemius (MG) tendon length using ultrasonography (US) requires the muscle-tendon junction (MTJ) to be located. Previously, the MG MTJ has been tracked from different proximo-distal locations near the MTJ, which could influence estimates of tendon length change due to the different characteristics of the aponeurosis and tendon. We used US to evaluate the effect of tracking point location on MG MTJ displacement during maximal and submaximal (10, 20 and 30% of the non-injured maximal) isometric plantar flexion contractions. METHODS Displacement behaviour of MTJ was tracked from (1) the exact MTJ; and (2) from an insertion point of a muscle fascicle on the aponeurosis 1.3 ± 0.6 cm proximal to the MTJ, in both limbs of patients with unilateral Achilles tendon rupture (ATR) (n = 22, 4 females, 42 ± 9 years, 177 ± 9 cm, 79 ± 10 kg). RESULTS In the non-injured limb, displacement (1.3 ± 0.5 cm vs. 1.1 ± 0.6 cm) and strain (6.7 ± 2.8% vs. 5.8 ± 3.3%) during maximal voluntary contraction were larger when tracking a point on the aponeurosis than when tracking the MTJ (both p < 0.001). The same was true for all contraction levels, and both limbs. CONCLUSION Tracking a point on the aponeurosis consistently exaggerates estimates of tendon displacement, and the magnitude of this effect is contraction intensity-dependent. When quantifying displacement and strain of the Achilles tendon, the MTJ should be tracked directly, rather than tracking a surrogate point proximal to the MTJ. The latter method includes part of the aponeurosis, which due to its relative compliance, artificially increases estimates of MTJ displacement and strain.
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Affiliation(s)
- Taija Finni
- Faculty of Sport and Health Sciences, Neuromuscular Research Centre, University of Jyväskylä, Viveca 227, Rautpohjankatu 8, 40700, Jyväskylä, Finland.
| | - Annamaria Peter
- Faculty of Sport and Health Sciences, Neuromuscular Research Centre, University of Jyväskylä, Viveca 227, Rautpohjankatu 8, 40700, Jyväskylä, Finland
| | - Ra'ad Khair
- Faculty of Sport and Health Sciences, Neuromuscular Research Centre, University of Jyväskylä, Viveca 227, Rautpohjankatu 8, 40700, Jyväskylä, Finland
| | - Neil J Cronin
- Faculty of Sport and Health Sciences, Neuromuscular Research Centre, University of Jyväskylä, Viveca 227, Rautpohjankatu 8, 40700, Jyväskylä, Finland.,School of Sport & Exercise, University of Gloucestershire, Gloucester, UK
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Stäudle B, Seynnes O, Laps G, Brüggemann GP, Albracht K. Altered Gastrocnemius Contractile Behavior in Former Achilles Tendon Rupture Patients During Walking. Front Physiol 2022; 13:792576. [PMID: 35299659 PMCID: PMC8921480 DOI: 10.3389/fphys.2022.792576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 02/01/2022] [Indexed: 11/17/2022] Open
Abstract
Achilles tendon rupture (ATR) remains associated with functional limitations years after injury. Architectural remodeling of the gastrocnemius medialis (GM) muscle is typically observed in the affected leg and may compensate force deficits caused by a longer tendon. Yet patients seem to retain functional limitations during-low-force-walking gait. To explore the potential limits imposed by the remodeled GM muscle-tendon unit (MTU) on walking gait, we examined the contractile behavior of muscle fascicles during the stance phase. In a cross-sectional design, we studied nine former patients (males; age: 45 ± 9 years; height: 180 ± 7 cm; weight: 83 ± 6 kg) with a history of complete unilateral ATR, approximately 4 years post-surgery. Using ultrasonography, GM tendon morphology, muscle architecture at rest, and fascicular behavior were assessed during walking at 1.5 m⋅s-1 on a treadmill. Walking patterns were recorded with a motion capture system. The unaffected leg served as control. Lower limbs kinematics were largely similar between legs during walking. Typical features of ATR-related MTU remodeling were observed during the stance sub-phases corresponding to series elastic element (SEE) lengthening (energy storage) and SEE shortening (energy release), with shorter GM fascicles (36 and 36%, respectively) and greater pennation angles (8° and 12°, respectively). However, relative to the optimal fascicle length for force production, fascicles operated at comparable length in both legs. Similarly, when expressed relative to optimal fascicle length, fascicle contraction velocity was not different between sides, except at the time-point of peak series elastic element (SEE) length, where it was 39 ± 49% lower in the affected leg. Concomitantly, fascicles rotation during contraction was greater in the affected leg during the whole stance-phase, and architectural gear ratios (AGR) was larger during SEE lengthening. Under the present testing conditions, former ATR patients had recovered a relatively symmetrical walking gait pattern. Differences in seen AGR seem to accommodate the profound changes in MTU architecture, limiting the required fascicle shortening velocity. Overall, the contractile behavior of the GM fascicles does not restrict length- or velocity-dependent force potentials during this locomotor task.
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Affiliation(s)
- Benjamin Stäudle
- Faculty of Medical Engineering and Technomathematics, Aachen University of Applied Sciences, Aachen, Germany
- Institute of Movement and Neurosciences, German Sport University Cologne, Cologne, Germany
| | - Olivier Seynnes
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Guido Laps
- Orthopädie am Gürzenich, Cologne, Germany
| | - Gert-Peter Brüggemann
- Institute of Biomechanics and Orthopedics, German Sport University Cologne, Cologne, Germany
| | - Kirsten Albracht
- Faculty of Medical Engineering and Technomathematics, Aachen University of Applied Sciences, Aachen, Germany
- Institute of Movement and Neurosciences, German Sport University Cologne, Cologne, Germany
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Khair RM, Stenroth L, Cronin NJ, Reito A, Paloneva J, Finni T. Muscle-tendon morphomechanical properties of non-surgically treated Achilles tendon 1-year post-rupture. Clin Biomech (Bristol, Avon) 2022; 92:105568. [PMID: 35066440 DOI: 10.1016/j.clinbiomech.2021.105568] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 10/12/2021] [Accepted: 12/30/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Achilles tendon rupture appears to alter stiffness and length of the tendon. These alterations may affect the function of tendon in force transmission and in energy storage and recovery. We studied the mechanical properties of the Achilles' tendon post-rupture and their association with function. METHODS Twenty-four (20 males, 4 females) participants (mean age: 43 y, 176 cm, 81 kg) were recruited. Ultrasonography and dynamometry were used to assess the muscle-tendon unit morphological and mechanical properties of non-surgically treated patients 1-year post rupture. FINDINGS Injured tendons were longer with difference of 1.8 cm (95%CI: 0.5-1.9 cm; P < 0.001), and thicker by 0.2 mm (0.2-0.3 mm; P < 0.01). Medial gastrocnemius cross-sectional area was 1.0 cm2 smaller (0.8-1.1 cm2; P < 0.001), fascicles were 0.6 cm shorter (0.5-0.7 cm; P < 0.001) and pennation angle was 2.5° higher (1.3-3.6°; P < 0.001) when compared to the uninjured limb. We found no differences between injured and uninjured tendon stiffness 1-year post-rupture (mean difference: 29.8 N/mm, -7.7-67.3 N/mm; P = 0.170). The injured tendon showed 1.8 mm (1.2-2.4 mm; P < 0.01) lower elongation during maximal voluntary isometric contractions. Patient-reported functional outcome was related to the tendon resting length (β = 0.68, r(10) = 4.079, P = 0.002). Inter-limb differences in the medial gastrocnemius fascicle length were related to inter-limb differences in maximum contractions (β = 1.17, r(14) = 2.808, P = 0.014). INTERPRETATION Longer Achilles tendon resting length was associated with poorer self-evaluated functional outcome. Although the stiffness of non-surgically treated and uninjured tendons was similar 1-year post rupture, plantar flexion strength deficit was still present, possibly due to shorter medial gastrocnemius fascicle length.
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Affiliation(s)
- Ra'ad M Khair
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland.
| | - Lauri Stenroth
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Neil J Cronin
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland; School of Sport & Exercise, University of Gloucestershire, UK
| | | | - Juha Paloneva
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland; Central Finland Health Care District, Finland
| | - Taija Finni
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland
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Stäudle B, Seynnes O, Laps G, Göll F, Brüggemann GP, Albracht K. Recovery from Achilles Tendon Repair: A Combination of Postsurgery Outcomes and Insufficient Remodeling of Muscle and Tendon. Med Sci Sports Exerc 2021; 53:1356-1366. [PMID: 33433154 DOI: 10.1249/mss.0000000000002592] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Achilles tendon rupture (ATR) patients have persistent functional deficits in the triceps surae muscle-tendon unit (MTU). The complex remodeling of the MTU accompanying these deficits remains poorly understood. The purpose of the present study was to associate in vivo and in silico data to investigate the relations between changes in MTU properties and strength deficits in ATR patients. METHODS Eleven male subjects who had undergone surgical repair of complete unilateral ATR were examined 4.6 ± 2.0 (mean ± SD) yr after rupture. Gastrocnemius medialis (GM) tendon stiffness, morphology, and muscle architecture were determined using ultrasonography. The force-length relation of the plantar flexor muscles was assessed at five ankle joint angles. In addition, simulations (OpenSim) of the GM MTU force-length properties were performed with various iterations of MTU properties found between the unaffected and the affected side. RESULTS The affected side of the patients displayed a longer, larger, and stiffer GM tendon (13% ± 10%, 105% ± 28%, and 54% ± 24%, respectively) compared with the unaffected side. The GM muscle fascicles of the affected side were shorter (32% ± 12%) and with greater pennation angles (31% ± 26%). A mean deficit in plantarflexion moment of 31% ± 10% was measured. Simulations indicate that pairing an intact muscle with a longer tendon shifts the optimal angular range of peak force outside physiological angular ranges, whereas the shorter muscle fascicles and tendon stiffening seen in the affected side decrease this shift, albeit incompletely. CONCLUSIONS These results suggest that the substantial changes in MTU properties found in ATR patients may partly result from compensatory remodeling, although this process appears insufficient to fully restore muscle function.
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Affiliation(s)
| | - Olivier Seynnes
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, NORWAY
| | - Guido Laps
- Orthopaedie am Guerzenich, Cologne, GERMANY
| | - Fabian Göll
- Institute of Movement and Neurosciences, German Sport University Cologne, Cologne, GERMANY
| | - Gert-Peter Brüggemann
- Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, GERMANY
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Sun D, Fekete G, Baker JS, Mei Q, István B, Zhang Y, Gu Y. A Pilot Study of Musculoskeletal Abnormalities in Patients in Recovery from a Unilateral Rupture-Repaired Achilles Tendon. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17134642. [PMID: 32605170 PMCID: PMC7369810 DOI: 10.3390/ijerph17134642] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 11/16/2022]
Abstract
The purpose of this study was to compare the inter-limb joint kinematics, joint moments, muscle forces, and joint reaction forces in patients after an Achilles tendon rupture (ATR) via subject-specific musculoskeletal modeling. Six patients recovering from a surgically repaired unilateral ATR were included in this study. The bilateral Achilles tendon (AT) lengths were evaluated using ultrasound imaging. The three-dimensional marker trajectories, ground reaction forces, and surface electromyography (sEMG) were collected on both sides during self-selected speed during walking, jogging and running. Subject-specific musculoskeletal models were developed to compute joint kinematics, joint moments, muscle forces and joint reaction forces. AT lengths were significantly longer in the involved side. The side-to-side triceps surae muscle strength deficits were combined with decreased plantarflexion angles and moments in the injured leg during walking, jogging and running. However, the increased knee extensor femur muscle forces were associated with greater knee extension degrees and moments in the involved limb during all tasks. Greater knee joint moments and joint reaction forces versus decreased ankle joint moments and joint reaction forces in the involved side indicate elevated knee joint loads compared with reduced ankle joint loads that are present during normal activities after an ATR. In the frontal plane, increased subtalar eversion angles and eversion moments in the involved side were demonstrated only during jogging and running, which were regarded as an indicator for greater medial knee joint loading. It seems after an ATR, the elongated AT accompanied by decreased plantarflexion degrees and calf muscle strength deficits indicates ankle joint function impairment in the injured leg. In addition, increased knee extensor muscle strength and knee joint loads may be a possible compensatory mechanism for decreased ankle function. These data suggest patients after an ATR may suffer from increased knee overuse injury risk.
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Affiliation(s)
- Dong Sun
- Faculty of Sports Science, Ningbo University, Ningbo 315211, China; (D.S.); (Q.M.); (Y.Z.)
| | - Gusztáv Fekete
- Savaria Institute of Technology, Eötvös Loránd University, 9700 Szombathely, Hungary;
| | - Julien S. Baker
- Department of Sport and Physical Education, Hong Kong Baptist University, Hong Kong 999077, China;
| | - Qichang Mei
- Faculty of Sports Science, Ningbo University, Ningbo 315211, China; (D.S.); (Q.M.); (Y.Z.)
| | - Bíró István
- Department of Technology, Faculty of Engineering, University of Szeged, 6727 Szeged, Hungary;
| | - Yan Zhang
- Faculty of Sports Science, Ningbo University, Ningbo 315211, China; (D.S.); (Q.M.); (Y.Z.)
| | - Yaodong Gu
- Faculty of Sports Science, Ningbo University, Ningbo 315211, China; (D.S.); (Q.M.); (Y.Z.)
- Correspondence: ; Tel.: +86-574-87600208
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Hullfish TJ, Baxter JR. A simple instrumented insole algorithm to estimate plantar flexion moments. Gait Posture 2020; 79:92-95. [PMID: 32388057 DOI: 10.1016/j.gaitpost.2020.04.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND Plantar flexion is critical for ambulatory function but there are few wearable solutions to monitor loading. RESEARCH QUESTION The purpose of this study was to develop and validate a method to calculate plantar flexion moment using a commercially-available instrumented insole. METHODS Seven healthy young adults completed a battery of functional activities to characterize a range of plantar flexion loading which included single leg heel raise, step down, and drop jump as well as walking and running at comfortable speeds. Lower extremity trajectories were captured using motion capture and ground reaction forces were recorded with embedded force plates as well as the instrumented insole. We compared plantar flexion moment calculated by the instrumented insole to 'gold standard' inverse dynamics. RESULTS We found that estimating plantar flexion moment using our instrumented insole algorithm compared favorably to moments calculated using inverse dynamics across all activities. Errors in the maximum plantar flexion moments were less than 10 % for all activities, averaging 4.9 %. Root mean square errors across the entire activity were also small, averaging 1.0 % bodyweight * height. Additionally, the calculated wave forms were strongly correlated with inverse dynamics (Rxy > 0.964). SIGNIFICANCE Our findings demonstrate the utility and fidelity of a simple method for estimating plantar flexion moment using a commercially available instrumented insole. By leveraging this simple methodology, it is now feasible to prospectively track and eventually prescribe plantar flexion loading outside of the clinic to improve patient outcomes.
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Affiliation(s)
- Todd J Hullfish
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Josh R Baxter
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA.
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11
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Drazan JF, Hullfish TJ, Baxter JR. Muscle structure governs joint function: linking natural variation in medial gastrocnemius structure with isokinetic plantar flexor function. Biol Open 2019; 8:bio.048520. [PMID: 31784422 PMCID: PMC6918776 DOI: 10.1242/bio.048520] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Despite the robust findings linking plantar flexor muscle structure to gross function within athletes, the elderly and patients following Achilles tendon ruptures, the link between natural variation in plantar flexor structure and function in healthy adults is unclear. In this study, we determined the relationship between medial gastrocnemius structure and peak torque and total work about the ankle during maximal effort contractions. We measured resting fascicle length and pennation angle using ultrasound in healthy adults (N=12). Subjects performed maximal effort isometric and isokinetic contractions on a dynamometer. We found that longer fascicles were positively correlated with higher peak torque and total work (R2>0.41, P<0.013) across all isokinetic velocities, ranging from slow (30°/s) to fast (210°/s) contractions. Higher pennation angles were negatively correlated with peak torque and total work (R2>0.296, P<0.067). These correlations were not significant in isometric conditions. We further explored this relationship using a simple computational model to simulate isokinetic contractions. These simulations confirmed that longer fascicle lengths generate more joint torque and work throughout a greater range of motion. This study provides evidence that ankle function is strongly influenced by muscle structure in healthy adults. Summary: Using ultrasound measurements of muscle structure and dynamometer measurements of ankle function, we found that longer muscle fascicles positively correlated with increased ankle kinetics.
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Affiliation(s)
- John F Drazan
- Department of Orthopedic Surgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Todd J Hullfish
- Department of Orthopedic Surgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Josh R Baxter
- Department of Orthopedic Surgery, University of Pennsylvania, Philadelphia, PA 19104, USA
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Hullfish TJ, O'Connor KM, Baxter JR. Medial gastrocnemius muscle remodeling correlates with reduced plantarflexor kinetics 14 weeks following Achilles tendon rupture. J Appl Physiol (1985) 2019; 127:1005-1011. [PMID: 31589091 DOI: 10.1152/japplphysiol.00255.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Deficits in plantarflexor kinetics are associated with poor outcomes in patients following Achilles tendon rupture. In this longitudinal study, we analyzed the fascicle length and pennation angle of the medial gastrocnemius muscle and the length of the Achilles tendon using ultrasound imaging. To determine the relationship between muscle remodeling and deficits in plantarflexor kinetics measured at 14 wk after injury, we correlated the reduction in fascicle length and increase in pennation angle with peak torque measured during isometric and isokinetic plantarflexor contractions. We found that the medial gastrocnemius underwent an immediate change in structure, characterized by decreased length and increased pennation of the muscle fascicles. This decrease in fascicle length was coupled with an increase in tendon length. These changes in muscle-tendon structure persisted throughout the first 14 wk following rupture. Deficits in peak plantarflexor torque were moderately correlated with decreased fascicle length at 120 degrees per second (R2 = 0.424, P = 0.057) and strongly correlated with decreased fascicle length at 210 degrees per second (R2 = 0.737, P = 0.003). However, increases in pennation angle did not explain functional deficits. These findings suggest that muscle-tendon structure is detrimentally affected following Achilles tendon rupture. Plantarflexor power deficits are positively correlated with the magnitude of reductions in fascicle length. Preserving muscle structure following Achilles tendon rupture should be a clinical priority to maintain plantarflexor kinetics.NEW & NOTEWORTHY In our study, we found that when the Achilles tendon ruptures due to excessive biomechanical loading, the neighboring skeletal muscle undergoes rapid changes in its configuration. The magnitude of this muscle remodeling explains the amount of ankle power loss demonstrated by these patients once their Achilles tendons are fully healed. These findings highlight the interconnected relationship between muscle and tendon. Isolated injuries to the tendon stimulate detrimental changes to the muscle, thereby limiting joint-level function.
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Affiliation(s)
- Todd J Hullfish
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kathryn M O'Connor
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Josh R Baxter
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
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