Electromyographic Evidence of Excessive Achilles Tendon Elongation During Isometric Contractions After Achilles Tendon Repair

Objectives: It has been proposed that increased tendon elongation after Achilles tendon repair contributes to selective weakness in end-range plantar flexion (Mullaney et al 2006). Excessive tendon elongation during maximum voluntary contraction (MVC) means greater muscle fiber shortening. Since mean frequency (MF) of the electromyogram (EMG) increases with muscle fiber shortening, it was hypothesized that during isometric plantar flexor MVCs MF would be higher on the involved versus non-involved side. Therefore, the purpose of this study was to examine MF during isometric MVCs in patients with Achilles tendon repairs. Methods: Maximum isometric plantar flexion torque was measured at 20° and 10° dorsiflexion, neutral, and 10° and 20° plantar flexion in 17 patients (mean±SD age, 39±9 years; 15 men, 2 women) 43±24 months after surgery (range, 9 months to 8 years). Surface EMG signals were recorded during strength tests. MF was calculated from Fast Fourier Transforms of medial gastroc (MG) lateral gastroc (LG) and soleus (S) EMG signals. Effect of weakness on MF was assessed using analysis of variance. Based on reported plantar flexor MF values it was estimated that with 17 subjects there would be 80% power to detect a 16% difference in MF between involved and noninvolved legs at P<0.05. Results: Patients had marked weakness in 20° plantar flexion (deficit 28±18%, P<0.01; 14 of 17 deficit >20%) but no significant weakness in 20° dorsiflexion (deficit 8±15%, P=0.20; 4 of 17 deficit >20%). MF increased moving from dorsiflexion to plantar flexion (P<0.001) but overall was not different between involved and noninvolved sides (P=0.22). However, differences in MF between the involved and noninvolved sides were apparent in the patients with marked weakness. At 10° plantar flexion 8 of 17 patients had marked weakness (>20% deficit). MF at 10° plantar flexion was significantly higher on involved versus noninvolved side in patients with weakness but this was not apparent in patients with no weakness (side by group P=0.014; Table 1). MF at 10° plantar flexion average across the 3 muscles was 13% higher on the involved versus noninvolved side in patients with weakness (P=0.012) versus 3% lower in patients with no weakness (P=0.47). Conclusion: Higher MF on the involved versus noninvolved side in patients with significant plantar flexion weakness is consistent with greater muscle fiber shortening. This indicates that weakness was primarily due to excessive lengthening of the repaired Achilles tendon. If weakness were simply due to atrophy, a lower MF would have been be expected and patients would have had weakness throughout the range of motion. Surgical and rehabilitative strategies are needed to prevent excessive tendon elongation and weakness in end-range plantar flexion after Achilles repair. [Table: see text]

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Electromyographic Evidence of Excessive Achilles Tendon Elongation During Isometric Contractions After Achilles Tendon Repair

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119883357 ◽

2019 ◽

Vol 7 (11) ◽

pp. 232596711988335

Author(s):

Malachy P. McHugh ◽

Karl F. Orishimo ◽

Ian J. Kremenic ◽

Julia Adelman ◽

Stephen J. Nicholas

Keyword(s):

Achilles Tendon ◽

Muscle Fiber ◽

Fourier Transforms ◽

Maximum Voluntary Contraction ◽

Tendon Repair ◽

Case Series ◽

Medial Gastrocnemius ◽

Level Of Evidence ◽

Achilles Tendon Repair ◽

Tendon Elongation

Background: Weakness in end-range plantarflexion has been demonstrated after Achilles tendon repair and may be because of excessive tendon elongation. The mean frequency (MNF) of surface electromyogram (EMG) data during isometric maximum voluntary contraction (MVC) increases with muscle fiber shortening. Hypothesis: During isometric plantarflexion, MNF during MVCs will be higher on the involved side compared with the uninvolved side after Achilles tendon repair because of excessive tendon elongation and greater muscle fiber shortening. Study Design: Case series; Level of evidence, 4. Methods: Isometric plantarflexion MVC torque was measured at 20° and 10° dorsiflexion, neutral, and 10° and 20° plantarflexion in 17 patients (15 men, 2 women; mean age, 39 ± 9 years) at a mean 43 ± 26 months after surgery. Surface EMG signals were recorded during strength tests. MNF was calculated from fast Fourier transforms of medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (SOL) EMG signals. Results: Patients had marked weakness on the involved side versus the uninvolved side in 20° plantarflexion (deficit, 28% ± 18%; P < .001) but no significant weakness in 20° dorsiflexion (deficit, 8% ± 15%; P = .195). MNF increased when moving from dorsiflexion to plantarflexion ( P < .001), but overall, it was not different between the involved and uninvolved sides ( P = .195). However, differences in MNF between the involved and uninvolved sides were apparent in patients with marked weakness. At 10° plantarflexion, 8 of 17 patients had marked weakness (>20% deficit). MNF at 10° plantarflexion was significantly higher on the involved side versus the uninvolved side in patients with weakness, but this was not apparent in patients with no weakness (side by group, P = .012). Mean MNF at 10° plantarflexion across the 3 muscles was 13% higher on the involved side versus the uninvolved side in patients with weakness ( P = .012) versus 3% lower in patients with no weakness ( P = .522). Conclusion: Higher MNF on the involved side versus the uninvolved side in patients with significant plantarflexion weakness is consistent with greater muscle fiber shortening. This indicates that weakness was primarily because of excessive lengthening of the repaired Achilles tendon. If weakness was simply because of atrophy, a lower MNF would have been expected and patients would have had weakness throughout the range of motion. Surgical and rehabilitative strategies are needed to prevent excessive tendon elongation and weakness in end-range plantarflexion after Achilles repair.

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Arthroscopically-Asissted Achilles Tendon Repair; Long-Term Results

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967114s00222 ◽

2014 ◽

Vol 2 (11_suppl3) ◽

pp. 2325967114S0022

Author(s):

Akın Turgut ◽

Mert Zeynel Asfuroğlu

Keyword(s):

Achilles Tendon ◽

Range Of Motion ◽

Sural Nerve ◽

Plantar Flexion ◽

Tendon Repair ◽

Long Term Results ◽

Calf Circumference ◽

Achilles Tendon Repair ◽

Arthroscopically Assisted

Objectives: The ruptures of the Achilles tendon (AT) are relatively common. Since there is no consensus on the best method of the repair of the AT; the treatment is determined on the preference of the surgeon and the patient. The study evaluating the cadaveric and short term clinical results done by our clinic in 2002, has shown us that arthroscopically Achilles tendon repair can be good choise in achilles tendon ruptures. Methods: Fortyfour patients who underwent arthroscopically assisted achilles tendon repair during 1997-2011 in Osmangazi University Orthopaedics and Traumatology Department were retrospectively observed. The mean follow-up time was 69,7 months. One of patients had bilateral rupture. The diagnosis was based on loss of plantar flexion strength, palpation of the gap in the tendon, and a positive Thompson test. MRI and USG were used when needed. The ruptures were left-sided in nineteen patients and right-sided in twentysix. The cause of the rupture was recreational sports activity in thirtyeight, fall from height in four, missing a step in a staircase in two. Return the regular activity, ankle range of motion as compared with the opposite side, calf circumference, and ability to walk and stand tiptoe were recorded. All patients were operated on within 2-32 days after the rupture. Thirtysix operations were performed under spinal anesthesia and eight operations were performed under general anesthesia. Tourniquet was always used. Before starting the procedure, the rupture site and location of the gap are marked. Using the common videoarthroscopic instruments, a 70 degrees scope was inserted into the AT through the stab incision made previously, and the torn ends of the tendon were visualized with plantar flexion an extension of the ankle. After the visualization of the torn ends of the tendon and repair by the technique of Ma and Griffith care was focused to contact the ends of the tendon anatomically; then the sutures were knotted. A short leg circular cast with the ankle in slight plantar flexion was applied. American Orthopaedics Foot-Ankle Society (AOFAS) score was used to evaluate the long-term results.. Results: All patients had satisfactory results that no reruptures had occurred. No significant difference in range of motion of the ankle and calf circumference between the opposite sides was observed in any patient. All patients could walk and stand on tiptoe. AOFAS mean score was 94.5 (65-100). The interval from injury to return to regular work and activities was 8-10 weeks. All the patients were able to return back to their activity level before surgery. In three patients temporary sural hypoestesia, in one patient permanent sural hipoestesia and in one patient wound enfection appeared. No sensory deficit was detected in the temporary sural hypoestesia patients after postoperative second year controls. Medical care was supported to the patient with the wound enfection and the enfection was under control in the early stages. Conclusion: In summary; arthroscopically-assisted percutaneous repair of AT appears to overcome some certain problems of open, conservative and percutaneous techniques; but the neurovascular structure damage risk especially the sural nerve remains a potent problem. Accurate knowledge of the anatomy appears to be a solution. Novel percutaneous repairs have been promising to minimize the risk of sural nerve damage.

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Achilles Tendon Mechanical Properties After Both Prolonged Continuous Running and Prolonged Intermittent Shuttle Running in Cricket Batting

Journal of Applied Biomechanics ◽

10.1123/jab.29.4.453 ◽

2013 ◽

Vol 29 (4) ◽

pp. 453-462 ◽

Cited By ~ 5

Author(s):

Laurence Houghton ◽

Brian Dawson ◽

Jonas Rubenson

Keyword(s):

Achilles Tendon ◽

Elastic Energy ◽

Plantar Flexion ◽

Maximum Voluntary Contraction ◽

Voluntary Contraction ◽

Force Transmission ◽

Before And After ◽

Tendon Force ◽

Force Displacement ◽

Tendon Properties

Effects of prolonged running on Achilles tendon properties were assessed after a 60 min treadmill run and 140 min intermittent shuttle running (simulated cricket batting innings). Before and after exercise, 11 participants performed ramp-up plantar flexions to maximum-voluntary-contraction before gradual relaxation. Muscle-tendon-junction displacement was measured with ultrasonography. Tendon force was estimated using dynamometry and a musculoskeletal model. Gradients of the ramp-up force-displacement curves fitted between 0–40% and 50–90% of the preexercise maximal force determined stiffness in the low- and high-force-range, respectively. Hysteresis was determined using the ramp-up and relaxation force-displacement curves and elastic energy storage from the area under the ramp-up curve. In simulated batting, correlations between tendon properties and shuttle times were also assessed. After both protocols, Achilles tendon force decreased (4% to 5%,P< .050), but there were no changes in stiffness, hysteresis, or elastic energy. In simulated batting, Achilles tendon force and stiffness were both correlated to mean turn and mean sprint times (r= −0.719 to −0.830,P< .050). Neither protocol resulted in fatigue-related changes in tendon properties, but higher tendon stiffness and plantar flexion force were related to faster turn and sprint times, possibly by improving force transmission and control of movement when decelerating and accelerating.

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Influence of static stretching on viscoelastic properties of human tendon structures in vivo

Journal of Applied Physiology ◽

10.1152/jappl.2001.90.2.520 ◽

2001 ◽

Vol 90 (2) ◽

pp. 520-527 ◽

Cited By ~ 206

Author(s):

Keitaro Kubo ◽

Hiroaki Kanehisa ◽

Yasuo Kawakami ◽

Tetsuo Fukunaga

Keyword(s):

Viscoelastic Properties ◽

Plantar Flexion ◽

Maximum Voluntary Contraction ◽

Voluntary Contraction ◽

Medial Gastrocnemius ◽

Static Stretching ◽

Tendon Elongation ◽

Before And After ◽

Human Tendon

The purpose of this study was to investigate the influences of static stretching on the viscoelastic properties of human tendon structures in vivo. Seven male subjects performed static stretching in which the ankle was passively flexed to 35° of dorsiflexion and remained stationary for 10 min. Before and after the stretching, the elongation of the tendon and aponeurosis of medial gastrocnemius muscle (MG) was directly measured by ultrasonography while the subjects performed ramp isometric plantar flexion up to the maximum voluntary contraction (MVC), followed by a ramp relaxation. The relationship between the estimated muscle force (Fm) of MG and tendon elongation ( L) during the ascending phase was fitted to a linear regression, the slope of which was defined as stiffness of the tendon structures. The percentage of the area within the Fm- L loop to the area beneath the curve during the ascending phase was calculated as an index representing hysteresis. Stretching produced no significant change in MVC but significantly decreased stiffness and hysteresis from 22.9 ± 5.8 to 20.6 ± 4.6 N/mm and from 20.6 ± 8.8 to 13.5 ± 7.6%, respectively. The present results suggest that stretching decreased the viscosity of tendon structures but increased the elasticity.

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Twelve-years’ experience in minimal invasive Achilles tendon repair using a suture-guiding device

Journal of Orthopaedics Trauma and Rehabilitation ◽

10.1177/2210491719837815 ◽

2019 ◽

Vol 26 (2) ◽

pp. 89-94

Author(s):

Prisca Yeung ◽

Lok Pong Man ◽

Wing Hang Angela Ho

Keyword(s):

Minimally Invasive ◽

Achilles Tendon ◽

Plantar Flexion ◽

Achilles Tendon Rupture ◽

Operating Time ◽

Tendon Repair ◽

Minimal Invasive ◽

Achilles Tendon Repair ◽

Invasive Method ◽

The Mean

Introduction: Minimal invasive Achilles tendon repair is becoming more and more popular recently. We have evaluated our results in Achilles tendon repair using minimally invasive method by a suture-guiding device. Methods: This is a retrospective review of patients with acute Achilles tendon rupture, which was repaired using minimally invasive method namely the suture-guiding device, that was performed during 2003 to 2015 in our department. Outcome parameters were the incidence of re-rupture, other complications, and the functional outcome. Results: There were 36 men (90%) and 4 women (10%) in this study. Mechanisms of injury were basketball (28%), football (15%), squash (15%), and trauma (13%). The mean operating time was 59 min (range 30–90 min). The mean follow-up time was 8 months (range 3–35 months). The mean duration with casting was 7 weeks. The mean range of movement at 3 months was 8° dorsiflexion and 33° plantar flexion. There was no major complication necessitating surgical re-interventions such as re-ruptures and infections. No patient suffered from dysfunction of the sural nerve or delay wound healing. Conclusion: Minimally invasive Achilles tendon repair using suture-guiding device is a safe and quick procedure with a low rate of re-rupture and a satisfactory short-term and long-term recovery. Level of evidence: IV.

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Can Weakness in End-Range Plantar Flexion After Achilles Tendon Repair Be Prevented?

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967118774031 ◽

2018 ◽

Vol 6 (5) ◽

pp. 232596711877403 ◽

Cited By ~ 2

Author(s):

Karl F. Orishimo ◽

Sidse Schwartz-Balle ◽

Timothy F. Tyler ◽

Malachy P. McHugh ◽

Benjamin B. Bedford ◽

...

Keyword(s):

Achilles Tendon ◽

Plantar Flexion ◽

Tendon Repair ◽

Joint Stiffness ◽

Case Series ◽

Neutral Position ◽

Passive Stiffness ◽

Force Transmission ◽

Passive Joint ◽

Achilles Tendon Repair

Background: Disproportionate end-range plantar flexion weakness, decreased passive stiffness, and inability to perform a heel rise on a decline after Achilles tendon repair are thought to reflect increased tendon compliance or tendon lengthening. Since this was first noted, we have performed stronger repairs and avoided stretching into dorsiflexion for the first 12 weeks after surgery. Hypothesis: Using stronger repairs and avoiding stretching into dorsiflexion would eliminate end-range plantar flexion weakness and normalize passive stiffness. Study Design: Case series; Level of evidence, 4. Methods: Achilles repairs with epitendinous augmentation were performed on 18 patients. Plantar flexion torque, dorsiflexion range of motion (ROM), passive joint stiffness, and standing single-legged heel rise on a decline were assessed at 43 ± 24 months after surgery (range, 9 months to 8 years). Maximum isometric plantar flexion torque was measured at 20° and 10° of dorsiflexion, neutral position, and 10° and 20° of plantar flexion. Passive dorsiflexion ROM was measured with a goniometer. Passive joint stiffness was computed from the increase in passive torque from 10° to 20° of dorsiflexion. Tendon thickness was measured by use of digital calipers. Plantar flexion electromyographic (EMG) data were recorded during strength and functional tests. Analysis of variance and chi-square tests were used to assess weakness and function. Results: Marked weakness was evident on the involved side at 20° of plantar flexion (deficit, 26% ± 18%; P < .001), with no weakness at 20° of dorsiflexion (deficit, 6% ± 17%; P = .390). Dorsiflexion ROM was decreased 5.5° ± 8° ( P = .015), and tendon width was 8 ± 3 mm greater on the involved side ( P < .001). Passive joint stiffness was similar between the involved and noninvolved sides. Only 2 of 18 patients could perform a decline heel rise on the involved side compared with 18 of 18 on the noninvolved side ( P = .01). No difference in EMG amplitude was found between the involved and noninvolved sides during the strength or heel rise tests. Conclusion: The use of stronger repair techniques and attempts to limit tendon elongation by avoiding dorsiflexion stretching did not eliminate weakness in end-range plantar flexion. EMG data confirmed that end-range weakness was not due to neural inhibition. Physiological changes that alter the force transmission capability of the healing tendon may be responsible for this continued impairment. This weakness has implications for high-demand jumping and sprinting after Achilles tendon repair.

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Difference in aftereffects following prolonged Achilles tendon vibration on muscle activity during maximal voluntary contraction among plantar flexor synergists

Journal of Applied Physiology ◽

10.1152/japplphysiol.00613.2004 ◽

2005 ◽

Vol 98 (4) ◽

pp. 1427-1433 ◽

Cited By ~ 45

Author(s):

Junichi Ushiyama ◽

Kei Masani ◽

Motoki Kouzaki ◽

Hiroaki Kanehisa ◽

Tetsuo Fukunaga

Keyword(s):

Achilles Tendon ◽

Muscle Activity ◽

Maximal Voluntary Contraction ◽

Plantar Flexion ◽

Voluntary Contraction ◽

High Threshold ◽

Plantar Flexor ◽

Afferent Activity ◽

Ia Afferent ◽

Before And After

It has been suggested that a suppression of maximal voluntary contraction (MVC) induced by prolonged vibration is due to an attenuation of Ia afferent activity. The purpose of the present study was to test the hypothesis that aftereffects following prolonged vibration on muscle activity during MVC differ among plantar flexor synergists owing to a supposed difference in muscle fiber composition. The plantar flexion MVC torque and surface electromyogram (EMG) of the medial head of gastrocnemius (MG), the lateral head of gastrocnemius (LG), and the soleus (Sol) were recorded in 13 subjects before and after prolonged vibration applied to the Achilles tendon at 100 Hz for 30 min. The maximal H reflexes and M waves were also determined from the three muscles, and the ratio between H reflexes and M waves (H/Mmax) was calculated before and after the vibration. The MVC torque was decreased by 16.6 ± 3.7% after the vibration ( P < 0.05; ANOVA). The H/Mmax also decreased for all three muscles, indicating that Ia afferent activity was successfully attenuated by the vibration in all plantar flexors. However, a reduction of EMG during MVC was observed only in MG (12.7 ± 4.0%) and LG (11.4 ± 3.9%) ( P < 0.05; ANOVA), not in Sol (3.4 ± 3.0%). These results demonstrated that prolonged vibration-induced MVC suppression was attributable mainly to the reduction of muscle activity in MG and LG, both of which have a larger proportion of fast-twitch muscle fibers than Sol. This finding suggests that Ia-afferent activity that reinforces the recruitment of high-threshold motor units is necessary to enhance force exertion during MVC.

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