Unilateral Achilles Tendon Rupture Research Articles

No detectable loss of myonuclei from human muscle fibers after six weeks of immobilization following an Achilles tendon rupture.

Muscle disuse has rapid and debilitating effects on muscle mass and overall health, making it an important issue from both scientific and clinical perspectives. However, the myocellular adaptations to muscle disuse are not yet fully understood, particularly those related to the myonuclear permanence hypothesis. Therefore, in this study, we assessed fiber size, number of myonuclei, satellite cells, and capillaries in human gastrocnemius muscle after a period of immobilization following an Achilles tendon rupture. Six physically active patients (5M/1F, 43 {plus minus} 15 years) were recruited to participate after sustaining an acute unilateral Achilles tendon rupture. Muscle biopsies were obtained from the lateral part of the gastrocnemius before and after six weeks of immobilization using a plaster cast and orthosis. Muscle fiber characteristics were analyzed in tissue cross-sections and isolated single fibers using immunofluorescence and high-resolution microscopy. Immobilization did not change muscle fiber type composition nor cross-sectional area of type I or type II fibers, but muscle fiber volume tended to decline by 13% (p=0.077). After immobilization, the volume per myonucleus was significantly reduced by 20% (p=0.008). Myonuclei were not lost in response to immobilization but tended to increase in single fibers and type II fibers. No significant changes were observed for satellite cells or capillaries. Myonuclei were not lost in the gastrocnemius muscle after a prolonged period of immobilization, which may provide support to the myonuclear permanence hypothesis in human muscle. Capillaries remained stable throughout the immobilization period, whereas the response was variable for satellite cells, particularly in type II fibers.

Prognosis of Nonconcurrent Bilateral Achilles Tendon Rupture Is Worse Than Unilateral Achilles Tendon Rupture: Patient-Reported Outcomes at Minimum 2-Year Follow-up.

Approximately 5%-7% of patients who have had Achilles tendon rupture (ATR) suffer from contralateral ATR. However, no studies have evaluated the clinical outcomes of contralateral ATR in patients with an existing ATR. Therefore, in this study, we aimed to investigate patient-reported ankle function and activity levels in patients with nonconcurrent bilateral ATR. We retrospectively reviewed the data of 222 patients with an acute ATR who presented at our 2 institutions between 2005 and 2017. All patients had a minimum 2-year follow-up period, with no other major injuries to the ankle joint. Of these patients, 17 patients had nonconcurrent bilateral ATR. Patient-reported outcomes were assessed by telephone interview, using the Achilles tendon Total Rupture Score (ATRS), the ankle activity score, and a patient satisfaction questionnaire. Telephonic interviews were conducted by 2 authors, using a prepared script to minimize bias owing to individual interviewers. The mean age of the patients was 45.1 ± 9.8 years, and 89% were men. Patients with nonconcurrent bilateral ATR had significantly lower values in terms of ATRS, ankle activity score, and satisfaction with current activity level, compared to patients who had unilateral ATR (p < 0.001, p = 0.027, and p = 0.012, respectively). Patients with nonconcurrent bilateral ATR had poorer ankle function, activity levels, and satisfaction than those with unilateral ATR in terms of patient-reported outcome measures with an intermediate-term result and a 2-year minimum follow-up period. These results emphasize the importance of the impact of contralateral injury on the prognosis of patients with ATR and the need for efforts to prevent contralateral rupture.

Tendon length estimates are influenced by tracking location

PurposeMeasurement 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.MethodsDisplacement 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).ResultsIn 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.ConclusionTracking 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.

Clinical Outcomes and Complications With Open vs Minimally Invasive Achilles Tendon Repair.

Background:There is no current consensus on whether to use an open or minimally invasive (MIS) approach for Achilles tendon repair after acute rupture. We hypothesized that patients in both open and MIS groups would have improved patient-reported outcome scores using the PROMIS system postoperatively, but that there would be minimal differences in these scores and complication rates between operative techniques.Methods:A total of 185 patients who underwent surgery for an acute, unilateral Achilles tendon rupture between January 2016 and June 2019, with minimum 1-year follow-up were included in the cohort studied. The minimally invasive group was defined by use of a commercially available minimally invasive device through a smaller surgical incision (n=118). The open repair group did not use the device, and suture repair was performed through larger surgical incisions (n=67). Postoperative protocols were similar between groups. Preoperative and postoperative PROMIS scores were collected prospectively through our institution’s registry. Demographics and complications were recorded.Results:PROMIS scores overall improved in both study groups after operative repair. No significant differences in postoperative PROMIS scores were observed between the open and MIS repair groups. There were also no significant differences in complication rates between groups. Overall, 19.5% of patients in the MIS group had at least 1 postoperative complication (8.5% deep vein thrombosis [DVT], 3.3% rerupture, 1.7% sural nerve injury, 2.5% infection), compared to 16.4% in the open group (9.0% DVT, 1.5% rerupture, 1.5% sural nerve injury, 0% infection).Conclusion:Patients undergoing either minimally invasive or open Achilles tendon repair after acute rupture have similar PROMIS outcomes and complication types and incidences.Level of Evidence:Level III, retrospective cohort study.

Structural and mechanical properties of the Achilles tendon in senior badminton players: Operated vs. non-injured tendons

BackgroundThe aim of this study was to describe the differences in structural and mechanical properties between operated and non-injured Achilles tendons in senior badminton players who had had Achilles tendon surgery and had returned to play. MethodsEighteen players (age = 48.9(10.0)years), assigned to the unilateral Achilles tendon rupture group and 177 non-injured players (age = 55.4(9.4)years), assigned to the control group. A Logiq®S8 ultrasound was used to study tendon structure and elastography index values and a Myoton®PRO hand-held myotonometer was used to record the stiffness of the Achilles tendon. FindingsIn Achilles tendon rupture group, operated tendons showed higher values than non-injured ones in thickness (Operated = 9.03(2.67)mm vs. non-injured = 5.88(0.88)mm; P < 0.001), width (Operated = 18.44(3.20)mm vs. non-injured = 16.80(1.97)mm; P = 0.039), cross sectional area (Operated = 140.33(60.29)mm2 vs. non-injured = 74.40(17.09)mm2; P < 0.001) and elastography index (Operated = 2.05(1.35)A.U. vs. non-injured = 1.47(0.62)A.U.; P = 0.025). The bilateral differences shown by the Achilles tendon rupture group were greater than the bilateral differences shown by the control group for thickness (P < 0.001), width (P = 0.001), cross sectional area (P < 0.001), tone (P = 0.006) and dynamic stiffness (Achilles tendon rupture group = 10.85(23.90)N∙m−1. vs. control group = 0.18(18.83)N∙m−1; P = 0.031). InterpretationSurgery on the Achilles tendon and adaptation to the mobilisation and strength training during rehabilitation could provoke structural and mechanical differences compared to the non-injured tendon. Furthermore, the differences between both Achilles tendons in the Achilles tendon rupture group was higher than the asymmetry observed between dominant and non-dominant Achilles tendons in the control group. In addition, the higher logarithmic decrement values showed by non-injured tendons in the Achilles tendon rupture group could be a tendinous injury risk factor.

Muscle Fascicles Exhibit Limited Passive Elongation Throughout the Rehabilitation of Achilles Tendon Rupture After Percutaneous Repair.

Achilles tendon rupture (ATR) results in long-term functional and structural deficits, characterized by reduced ankle mobility and plantarflexor muscle atrophy. However, it remains unclear how such functional impairments develop after surgical repair. While it is known that this injury negatively affects the tendon’s function, to date, limited work has focused on the short-term effect of ATR on the structure of the muscles in series. The aim of this study was to characterize changes in medial gastrocnemius architecture and its response to passive lengthening during the post-surgical rehabilitative period following ATR. Both injured and contralateral limbs from 10 subjects (1 female, BMI: 27.2 ± 3.9 kg/m2; age: 46 ± 10 years) with acute, unilateral ATR were assessed at 8, 12, and 16 weeks after percutaneous surgical repair. To characterize the component tissues of the muscle-tendon unit, resting medial gastrocnemius muscle thickness, fascicle length, and pennation angle were determined from ultrasound images with the ankle in both maximal plantarflexion and dorsiflexion. The ankle range of motion (ROM) was determined using motion capture; combined ultrasound and motion capture determined the relative displacement of the musculotendinous junction (MTJ) of the AT with the medial gastrocnemius. The ATR-injured gastrocnemius muscle consistently exhibited lower thickness, regardless of time point and ankle angle. Maximal ankle plantarflexion angles and corresponding fascicle lengths were lower on the injured ankle compared to the contralateral throughout rehabilitation. When normalized to the overall ankle ROM, both injured fascicles and MTJ displacement exhibited a comparably lower change in length when the ankle was passively rotated. These results indicate that when both ankles are passively exposed to the same ROM following ATR surgery, both ipsilateral Achilles tendon and gastrocnemius muscle fascicles exhibit limited lengthening compared to the contralateral MTU tissues. This appears to be consistent throughout the rehabilitation of gait, suggesting that current post-operative rehabilitative exercises do not appear to induce muscle adaptations in the affected MTU.

Case Study: Shear Wave Tensiometry Detects Asymmetry In Achilles Loading During Gait After Unilateral Rupture

Achilles tendon ruptures are debilitating injuries that lead to long-term functional deficits in two thirds of patients. Shear wave tensiometry is a non-invasive technique for measuring tendon loading during functional activities by inducing waves traveling along the tendon and measuring their propagation speed. Tensiometers have the potential to be implemented in clinical settings to objectively track tendon loading to assist in clinical decision-making. PURPOSE: To determine whether shear wave tensiometry can detect abnormalities in tendon loading during recovery following Achilles tendon rupture and repair. METHODS: Tensiometers were placed bilaterally on the Achilles tendons of one subject who had undergone surgical repair of a unilateral Achilles tendon rupture 14 weeks prior (M, 87.6 kg, 193 cm) and two control subjects (M, 75.0 kg, 188 cm; M, 100.0 kg, 185 cm). Each subject first performed isometric ankle plantarflexion contractions while wave speed and joint torque were measured. Tendon force was estimated from torque by assuming a normative 5 cm Achilles moment arm. Isometric data were used to calibrate a linear model for predicting tendon force from wave speed squared. The subject then walked on a treadmill (patient: 1.25 m/s; controls: 1.50 m/s) while Achilles tendon wave speed was recorded bilaterally. Plantarflexor impulse was calculated by integrating predicted tendon force over each stance phase. RESULTS: We estimate that the patient produced a 40% lower plantarflexor impulse on the injured side (4.8 ± 0.4 N·s·kg-1; mean ± SD) compared to the healthy side (8.0 ± 1.0 N·s·kg-1), while the side-to-side differences for control subjects were 5% (8.4 ± 0.4 N·s·kg-1 vs. 8.0 ± 0.2 N·s·kg-1) and 2% (10.7 ± 0.7 N·s·kg-1 vs. 10.5 ± 1.0 N·s·kg-1), respectively. CONCLUSION: Tensiometer data show that the patient adopted a gait pattern that underloaded the healing tendon. This is important to consider given that early loading exposure may be an important determinant of long-term healing and structure of the repaired tissue. This study establishes the feasibility of using shear wave tensiometry to quantify tendon load during clinical assessments of patients with tendon injuries, which is an unmet clinical need. Supported by the Thomas B. and Jeannette E. Laws McCabe Fund and the Wisconsin Alumni Research Foundation.

Prognosis of elite basketball players after an Achilles tendon rupture

ObjectiveProfessional Basketball players are at high risk of Achilles tendon rupture. Despite this, there remains limited research into the factors affecting rehabilitation and the long term outcomes of these players. Our aim is to quantify the effect of a player’s Achilles tendon rupture on their post-injury performance, and also to explore for correlations between their recovery timeline and pre-injury characteristics. Creation of an injury timeline of past incidents will allow injured players to better track their progress and also inform them about the probable impact on their careers. HypothesisPlayers with Achilles tendon rupture injury will exhibit decreased performance compared to their pre-injury self and their non-injured peers after recovery. MethodsProfessional basketball players who sustained a unilateral Achilles tendon rupture from 1992 to 2016 were collected. 12 players met our inclusion criteria and their Player Efficiency Ratings (PER) were obtained as primary outcome measures; matched controls were chosen based on the PER, Age and playing position. The players’ index season PER was compared against the PER during the 10 games immediately following the players’ return and the PER of their post-injury peak performing season. The same data analysis was performed against their control group. To investigate the factors affecting the recovery and long-term consequences of their injury, we correlated the variables of Age, BMI, Time of Injury and pre-injury PER with the player’s time to return to play and their post-injury PER. Results2 out of 12 players failed to return to playing in the elite professional league following an Achilles Tendon Rupture, others returned after a mean recovery time of 10 months. When compared to players’ index PER, the mean PER reduction during the 10 games immediately following the players’ return was 7.15 (P < .000). Players on average took 1.8 seasons to reach their post-injury peak performance, with only 1 player returning to his pre-injury performance. Others suffered a mean PER reduction of 3.5 (P = .004) when compared to their index PER and 5.4 (P = .045) against their matched controls. ConclusionAchilles tendon rupture can be a career-ending injury for professional basketball players. They are expected to miss 10 months for rehabilitation and reach their post-injury peak performance level at the 2nd season back. The post-injury peak performance is significantly worse than the pre-injury level, but is similar to matched non-injured players.

Impact of seated and standing positions on triceps surae muscle activation in unilateral Achilles tendon rupture.

Heel-rises are commonly used in the rehabilitation of individuals following Achilles tendon rupture, however, the impact of tendon elongation on triceps surae activation in seated versus standing positions has not been investigated. The purpose of this study was to investigate changes in triceps surae activation during seated compared to standing heel-rises in individuals with Achilles tendon rupture and its relationship to tendon elongation. Ten individuals with a history of Achilles tendon rupture were included in this study. Muscle activity using electromyography was examined during a heel-rise task in seated (unilateral) and standing (bilateral) positions. Soleus activity was not significantly different between sitting and standing on both the ruptured and uninjured side. On the ruptured, side there were no differences in medial or lateral gastrocnemius activity between sitting and standing; however, on the uninjured side medial and lateral gastrocnemius activity was lower in sitting compared to standing. The results of this study suggest that neuromuscular changes in triceps surae activation occur following Achilles tendon rupture. The seated heel-rise position can be used to strengthen all muscles of the triceps surae and is useful when the patient is unable to perform a standing heel-rise.

Muscle activation during maximum voluntary contraction and m-wave related in healthy but not in injured conditions: Implications when normalizing electromyography

BackgroundElectromyography signal amplitude is influenced by a variety of factors. Normalization strategies aimed at decreasing signal variability include using peak electromyography signal during a maximum voluntary contraction and peak-to-peak M-wave amplitude. However, whether these normalization methods are comparable has not been investigated in injured populations. This study investigated the relationship between peak signal during maximum voluntary contraction and M-wave amplitude in individuals with a unilateral Achilles tendon rupture. Secondarily, we observed whether the two normalizations strategies would yield similar results when evaluating between limb differences in muscle activity during a jump task. MethodsEleven individuals 1–3 years after a unilateral Achilles tendon rupture were included in this study. Surface electromyography was used on the medial and lateral gastrocnemii bilaterally. Peak maximum voluntary contraction, M-wave amplitude, and electromyography during a jumping task were collected. FindingsA strong relationship was observed between peak maximum voluntary contraction and M-wave amplitude on the uninjured (r = 0.71–0.88, P < 0.05) but not on the ruptured side (r = 0.41–0.44, P > 0.05). The two normalization techniques did not produce different results when comparing the uninjured and ruptured sides. InterpretationThe findings of this study suggest that M-wave normalization yields similar results as peak maximum voluntary contraction-normalized electromyography in uninjured conditions. M-wave normalization may be a useful strategy in an injured population where a maximal muscle contraction is unsafe or impaired.

Gait Abnormality and Asymmetry Analysis After 18–24 Months Surgical Repair of Unilateral Achilles Tendon Rupture

Gait Abnormality and Asymmetry Analysis After 18–24 Months Surgical Repair of Unilateral Achilles Tendon Rupture

Speckle tracking in healthy and surgically repaired human Achilles tendons at different knee angles-A validation using implanted tantalum beads

The exact injury mechanism of Achilles tendinopathy remains unknown, but sliding of fascicles relative to each other during loading may be an important factor. This study validated the motion of ultrasound speckles against actual tendon movement using tantalum beads as reference markers. In addition, the effect of different knee joint angles (ie, muscle activation) on tendon tissue shear and displacement during a single heel rise was investigated. The 10 male participants had tantalum beads inserted in the tendon during surgery for a unilateral Achilles tendon rupture at least 1 year prior to the study. Ultrasound speckle displacement in the tissue surrounding the bead correlated strongly with displacement of the bead (R2 ≥ .9987). Speckle tracking systematically underestimated the displacement of the tendon tissue with a typical error of 1.1%-2.7%. There was a significant difference in displacement between the superficial and deep tendon layer for the 3 exercises in the healthy, but not in the surgically repaired Achilles tendon. The displacement difference was significantly greater when performing heel rises with the knee flexed 100° compared to knee flexed 40°. In conclusion, speckle tracking appears to be a valid approach to investigate intratendinous displacement.

Achilles Tendon Resting Angle Relates to Tendon Length and Function.

Following Achilles tendon rupture, tendon elongation leads to long term deficits in calf function. A surrogate measure of Achilles tendon length, Achilles tendon resting angle (ATRA), has been described but has not been validated against length measured using ultrasound. Therefore, the purpose of this study was to validate the ATRA against ultrasound. Secondarily, this study aimed to identify the relationship of other factors (tendon mechanical properties, heel-rise test performance) to the ATRA. Individuals following unilateral Achilles tendon rupture were included. ATRA was measured in knee flexed and extended positions. Tendon elongation was measured using extended field of view ultrasound imaging. Continuous shear wave elastography quantified tendon mechanical properties. The relationship between variables was tested using Spearman's ρ. Subgroup analysis was used to compare subjects with less then or greater than 1 year following rupture. A total of 42 participants (with a mean of 18.2 months following rupture [SD = 35.9]) were included. Tendon elongation related with relative ATRA with knee flexed (ρ = .491, P = .001) and knee extended (ρ = 0.501, P = .001) positions. In individuals greater than 1 year following rupture, relative ATRA with the knee flexed related to shear modulus (ρ = .800, P = .01) and total work on the heel-rise test (ρ = -.782, P = .008) relative to the uninjured side. Relative ATRA in both knee flexed and knee extended positions has a moderate relationship to tendon elongation within the first year following rupture. After 1 year, the relative ATRA with knee flexed may be a better indicator of tendon elongation and also related to tendon mechanical properties and heel-rise test performance. Level III, case-control study.

Use of ankle resting angle as a surrogate for tendon elongation in individuals following Achilles tendon rupture

Category: Ankle, Sports Introduction/Purpose: Tendon elongation is associated with poor functional outcome in individuals after Achilles tendon rupture. While imaging modalities are reliable to measure Achilles tendon length, alternative time- and cost-effective measures are of interest. The resting angle of the ankle in prone both with knee extended1 and knee flexed2 have been used in the literature as surrogates for measuring Achilles elongation, however, their relationship to tendon length is not well-established. The purpose of this study is to validate the ankle resting angle as a measure of tendon elongation and examine the relationship of ankle resting angle to tendon elongation and calf strength. Methods: Individuals following unilateral Achilles tendon rupture, treated surgically, were included in this cross-sectional study. Individuals were excluded if they had deep wound infection or lumbar radiculopathy affecting the ankle plantar flexors. Ankle resting angle with knee extended and knee flexed to 90 degrees was measured using a digital inclinometer positioned on the lateral, plantar surface of the foot. Relative resting angle was calculated by subtracting the uninjured from the injured side. Tendon length to gastrocnemius was measured using B mode, extended field of view ultrasound imaging3 (tendon elongation = ruptured- uninjured). Calf strength was measured using the heel-rise test4. Limb symmetry indexes (LSI) were calculated (ruptured/uninjured sidex100) for total work performed on the heel-rise test. Results: Twenty-five individuals, a mean(SD) age of 44.2(13.6) years and mean(SD) of 22.5(39.1) months post-rupture, were included in this study. Mean(SD) relative resting angle with knee flexed was -5.4(6.4)° and mean (SD) relative resting angle with knee extended was -6.7(8.8)°. Mean(SD) tendon elongation was 1.56(1.20)cm. Mean(SD) heel-rise test work LSI was 45.8(23.8)%. Ankle resting angle with knee flexed related to elongation (r = -0.452, p = 0.027) and heel-rise test work LSI (r = 0.591, p=0.006). Ankle resting angle with knee extended related to elongation (r=-0.528, p=0.008) (Figure 1) but not heel-rise test work LSI. Conclusion: The results of this study suggest that ankle resting angle with knee extended and flexed are related to tendon elongation, however, calf strength also has a relationship to resting angle with knee flexed. This suggests that the ability of the calf to put passive tension on the foot is also a component of resting angle. The relationship between tendon elongation and resting angle with knee flexed may have been limited by methodological concerns, as tendon length was measured with the participant positioned with knees extended.

Management of acute Achilles tendon rupture with tendon-bundle technique.

Objective*These authors contributed equally to this work.To explore tendon-bundle technique for treating Achilles tendon rupture with no defects.MethodsPatients with full unilateral Achilles tendon rupture with no defects were included. The Achilles tendon medial edge surgical repair approach was used, revealing horsetail-like rupture bundles. Tendon bundles were anatomically realigned and repaired end-to-end using 5-0 sutures. Patients were followed-up for 1 year, and assessed for differences between the repaired versus healthy limb.ResultsOut of 24 patients (18 male, 6 female; aged 19–56 years) at 1 year following surgery, mean American Orthopaedic Foot and Ankle Society score was 92.4 ± 5.9; mean differences between the surgically repaired versus contralateral side in dorsiflexion and plantarflexion angle were 3.5 ± 2.3° and 5.6 ± 3.2°, respectively; mean difference in calf circumference between the two sides was 0.9 ± 0.5 cm; and mean increase in Achilles tendon width versus the healthy side was 0.8 ± 0.2 cm. By 1 year post-surgery, there were no significant between-side differences in dorsiflexion and plantarflexion angle, or calf circumference.ConclusionsTendon-bundle surgery resulted in good ankle function restoration and low complication rates. Tendon-bundle surgery may reduce blood supply destruction and maximally preserve Achilles tendon length, and may be effective for treating Achilles tendon rupture with no defects.

Neuromechanical Modulation of the Achilles Tendon During Bilateral Hopping in Patients with Unilateral Achilles Tendon Rupture, Over 1 Year After Surgical Repair.

Patients who have had an Achilles tendon (AT) rupture repaired are potentially at higher risk for re-rupture than those without previous rupture. Little attention has been given to the neuromechanical modulation of muscle-tendon interaction and muscle activation profiles during human dynamic movements after AT rupture repair. The purpose of this study was to examine muscle-tendon behavior and muscle activation during bilateral hopping. We enrolled nine subjects who had undergone surgical repair of unilateral AT rupture within the past 1-2years. Subjects performed bilateral hopping while we took ultrasound, kinematic, and electromyogram recordings and measurements. AT behaviors were also recorded. We then compared responses between values obtained from the ruptured AT leg (LEGATR) and non-ruptured AT leg (LEGNOR). During hopping, the AT stretching amplitudes were greater in the LEGATR than in the LEGNOR, although the peak AT force and stiffness were smaller in the LEGATR than in the LEGNOR. The AT negative mechanical work did not show any significant differences between both legs. However, positive works were significantly lower in the LEGATR than in the LEGNOR. Electromyogram patterns in both soleus and tibialis anterior muscles clearly differed after ground contact for the LEGATR and the LEGNOR. These results suggest that the repaired ruptured AT can be compliant and have insufficient Young's modulus, which can influence mechanical responses in muscle activities. The modulation of agonist-antagonist muscle activities corresponding to the different levels of stiffness between the LEGATR and the LEGNOR may not be fully functioning during the pre-activation phase.

Percutaneous repair of acute Achilles tendon rupture: a functional evaluation study with a minimum 10-year follow-up.

The purpose of this study was to present the functional outcomes of percutaneous tenorrhaphy of the Achilles tendon with a minimum follow-up of 10 years. The medical records of patients who underwent percutaneous surgery for acute unilateral Achilles tendon rupture between 2000 and 2004 were retrospectively reviewed. A total of 11 male patients met the inclusion criteria and were followed for a mean of 12.6 years (range: 10-13 years). The average age at the time of surgery was 39.3 years (range: 29-53 years). Patients returned to work at an average of 2.7 months (range: 1-4 months) after surgery and to normal daily activities (NDA) at an average of 4.1 months (range: 3-6 months) postoperatively. The mean strength ratio between the injured and normal sides was 90%. Compared with the contralateral normal side, the thickness of the operated tendon increased by a mean of 0.7 cm, while the circumference of the affected calf diminished by a mean of 1.1 cm. No difference in active and passive range of motion (ROM) was recorded between the affected and the contralateral normal ankle joints. Isometric plantar flexion was 87% of normal. Sensory impairment in the territory of the sural nerve was identified in 1 patient immediately after surgery. The sensory defect had completely resolved by 6 months postoperatively. Long-term outcomes of our series support the effectiveness of percutaneous tenorrhaphy in Achilles function rehabilitation of patients with acute ruptures.

Long-term biomechanical outcomes after Achilles tendon ruptures

The ideal treatment for Achilles tendon ruptures is still unknown. Biomechanical were correlated to radiological and clinical parameters to study outcomes. In this retrospective, assessor-blinded multi-centre cohort study, 52 patients with unilateral Achilles tendon rupture were assessed, each at least 3 years after injury. Patients underwent open surgery, percutaneous surgery or non-surgical treatment of Achilles tendon rupture. Both legs underwent plantar pressure distribution and isokinetic measures. Demographic parameters, maximum calf circumference (MCC) and clinical scores (American Orthopaedic Foot and Ankle Society, Achilles tendon rupture score, Hannover) were also evaluated. Complications were not assessed. Peak plantar flexion torque (PPFT) was significantly weaker on the treated side compared to the untreated leg [80.4 ± 29.7 Nm (mean ± SD) vs. 92.1 ± 27.4 Nm, p < 0.0001]. PPFT and push-off force (POFF) were not different between treatment groups nor was there a leg difference in POFF alone. There was only a weak correlation of clinical scores and PPFT or POFF, respectively. MCC correlated significantly with both PPFT (R (2) = 0.21, p = 0.01) and POFF (R (2) = 0.29, p < 0.0001). POFF appeared to be a predictor of PPFT (R (2) = 0.31, p < 0.0001). Open surgery outperformed non-surgical treatment in terms of centre-of-pressure line (p = 0.007), torque per muscle volume (p = 0.04) and relative POFF per body weight (p = 0.02) and relative in side comparison (p = 0.03). Clinical scores do not predict biomechanical outcomes. Clinically measured MCC is a good predictor of PPFT and POFF and can easily be used in clinical practice. Relative POFF in side comparison as well as per body weight favours surgical treatment.

Long-term outcomes of muscle volume and Achilles tendon length after Achilles tendon ruptures

The best treatment for Achilles tendon (AT) ruptures remains controversial. Long-term follow-up with radiological and clinical measurements is needed. In this retrospective multicentre cohort study, patients (n = 52) were assessed at a mean of 91 months follow-up after unilateral AT rupture treated by open, percutaneous or conservative (non-surgical) treatment. Demographic parameters, time off work, maximum calf circumference and clinical scores (ATRS, Hannover, AOFAS) were evaluated. Muscle volume and cross-sectional area of the calf and AT length were measured on MR images and were compared between groups and to each patient's healthy contralateral leg. Reduced muscle volume was found across all groups with a higher muscle volume in the conservative (729.9 ± 130.3 cm(3)) compared to the percutaneous group (675.9 ± 207.4 cm(3), p = 0.04). AT length was longer in the affected leg (198.4 ± 24.1 vs. 180.6 ± 25.0 mm, p < 0.0001) without difference in subgroup analysis. Clinically measured ankle dorsiflexion showed poor correlation with AT length (R (2) = 0.07, p = 0.008). Muscle volume strongly correlated with the cross-sectional area (R (2) = 0.6, p < 0.0001) but showed a weak correlation with the Hannover score (R (2) = 0.08, p = 0.048). Maximum calf circumference correlated with muscle volume (R (2) = 0.42, p < 0.0001). No significant difference between the treatment groups was found in muscle volume, AT length, clinical measures or days off work. Cross-sectional area and maximum calf circumference are cost-effective measurements and a good approximation of muscle volume and can thus be used in a clinical setting while clinical dorsiflexion should not be used.

Analysis of achilles tendon vascularity with second‐generation contrast‐enhanced ultrasound

To compare morphological, power Doppler, and contrast-enhanced ultrasound (CEUS) features of the Achilles tendon between asymptomatic athletes and athletes who had undergone surgical repair of a previous rupture. Twenty-four athletes were divided in two groups (A and B). Group A included 14 patients with a median age of 32 years (range 27 to 47 years) who had undergone surgical repair for unilateral Achilles tendon rupture. Group B (control group) included 10 subjects with a median age of 34 years (range 27 to 40 years) with no previous or present history of tendinopathy. All patients were evaluated with ultrasound, power Doppler, and CEUS with second-generation contrast agent. We studied the uninjured Achilles tendon in athletes of group A and either the left or the right Achilles tendon of the athletes in group B. CEUS showed a significantly greater ability to detect a greater number of vascular spots within the uninjured tendon of group A compared to group B (<0.05). In athletes who had suffered a tear of an Achilles tendon, CEUS detected small vessels that were not identified by power Doppler ultrasound in the uninjured contralateral Achilles tendon. CEUS is useful to evaluate vascularity not detected by other imaging techniques. Vascularity in the uninjured tendon seems to be increased in patients who had a previous rupture.