Biomechanical behavior of the plantar flexor muscle-tendon unit after an Achilles tendon rupture

No effects of early functional mobilization on gait patterns after acute Achilles tendon rupture repair

This study aimed to compare recovery of gait patterns in patients treated with early functional mobilization (EFM) or standard treatment (ST) after Achilles tendon rupture repair. Second, this study aimed to explore associations between gait patterns and tendon elongation and calf muscle atrophy, respectively. Forty-seven patients (12 females), mean age 38.7 (7.3) years, were included. Patients were postoperatively randomized to EFM (n = 29), including immediate weightbearing and ankle motion for 6 weeks, or ST (n = 18), with 2 weeks of unloading in a plaster cast followed by 4 weeks of weightbearing in an orthosis. Three-dimensional gait analyses were performed at 8 weeks and 6 months postoperatively to evaluate ankle and knee kinematics and kinetics. Ultrasound imaging was performed to assess tendon length and calf muscle atrophy. At 8 weeks, there were no significant group differences in ankle and knee kinematics and kinetics, while side-to-side differences between injured and uninjured side were present within both groups. At 6 months, the ST group exhibited higher generating ankle power and greater peak moments in ankle and knee compared to the EFM group. In both groups, peak ankle dorsiflexion angle was greater on the injured side compared to the uninjured side. No correlations were found between ankle joint gait deviations and degree of tendon elongation or muscle atrophy. Clinical significance: The accelerated rehabilitation regimen with EFM did not result in a more symmetrical gait pattern. The gait pattern deviations in the ankle joint were not related to the degree of muscle atrophy or tendon elongation.

The Intelligent Phenotypic Plasticity Platform (IP3) for Precision Medicine-Based Injury Prevention in Sport

The best predictor of future injury is previous injury and this has not changed in a quarter century despite the introduction of evidence-based medicine and associated revisions to post-injury treatment and care. Nearly nine million sports-related injuries occur annually, and the majority of these require medical intervention prior to clearance for the athlete to return to play (RTP). Regardless of formal care, these athletes remain two to four times more likely to suffer a second injury for several years after RTP. In the case of children and young adults, this sets them up for a lifetime of negative health outcomes. Thus, the initial injury is the tipping point for a post-injury cascade of negative sequelae exposing athletes to more physical and psychological pain, higher medical costs, and greater risk of severe long-term negative health throughout their life. This chapter details the technologies and method that make up the automated Intelligent Phenotypic Plasticity Platform (IP3)-a revolutionary new approach to the current standard of post-injury care that identifies and targets deficits that underly second injury risk in sport. IP3 capitalizes on the biological concept of phenotypic plasticity (PP) to quantify an athlete's functional adaptability across different performance environments, and it is implemented in two distinct steps: (1) phenomic profiling and (2) precision treatment. Phenomic profiling indexes the fitness and subsequent phenotypic plasticity of an individual athlete, which drives the personalization of the precision treatment step. IP3 leverages mixed-reality technologies to present true-to-life environments that test the athlete's ability to adapt to dynamic stressors. The athlete's phenotypic plasticity profile is then used to drive a precision treatment that systematically stresses the athlete, via a combination of behavioral-based and genetic fuzzy system models, to optimally enhance the athlete's functional adaptability. IP3 is computationally light-weight and, through the integration with mixed-reality technologies, promotes real-time prediction, responsiveness, and adaptation. It is also the first ever phenotypic plasticity-based precision medicine platform, and the first precision sports medicine platform of any kind.

Recovery from Achilles Tendon Repair: A Combination of Postsurgery Outcomes and Insufficient Remodeling of Muscle and Tendon

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.

Assessment of the Maximal Range of Motion from Initial Sensation of Stretching to the Limits of Tolerance

The aim of this study was to determine whether the first sensation of stretching (ROM_FSS) may predict the maximum range of motion (ROM_MAX) in male (N = 37) and female (N = 32) volunteer subjects, and to assess the reliability of the ROM perceived by subjects in relation to a pre-determined ROM (ROM_50%). Subjects attempted three experimental sessions with 48 hours between sessions 1 and 2 and 28 days between sessions 1 and 3. Within each session, five trials were performed with isokinetic equipment to assess posterior thigh muscle flexibility. The results revealed a strong and significant correlation between ROM_MAX and ROM_FSS for both sexes, females (r = 0.96, p < 0.001, R ² = 0.92) and males (r = 0.91, p < 0.001; R ² = 0.82). The accuracy of the model verified by the standard error of estimate (SEE) was high in the equations proposed for both female (SEE = 4.53%) and male (SEE = 5.45%). Our results revealed that ROM_FSS may predict the ROM_MAX for both male and female subjects. The ROM_FSS may contribute to the development of evaluation methods that do not subject the individuals to conditions that may include unnecessary risk of injury and is well suited to monitor the training process of stretching exercises with submaximal loads.

Changes of Material Elastic Properties during Healing of Ruptured Achilles Tendons Measured with Shear Wave Elastography: A Pilot Study

Therapy options for ruptured Achilles tendons need to take into account the right balance of timing, amount and intensity of loading to ensure a sufficient biomechanical resilience of the healing tendon on the one hand, and to enable an adequate tensile stimulus on the other hand. However, biomechanical data of human Achilles tendons after rupture during the separate healing stages are unknown. Shear wave elastography is an ultrasound technique that measures material elastic properties non-invasively, and was proven to have a very good correlation to biomechanical studies. Taking advantage of this technology, 12 patients who suffered from an acute Achilles tendon rupture were acquired and monitored through the course of one year after rupture. Nine of these patients were treated non-operatively and were included for the analysis of biomechanical behaviour. A significant increase of material elastic properties was observed within the first six weeks after trauma (up to 80% of baseline value), where it reached a plateau phase. A second significant increase occurred three to six months after injury. This pilot study suggests a time correlation of biomechanical properties with the biological healing phases of tendon tissue. In the reparative phase, a substantial amount of biomechanical resilience is restored already, but the final stage of biomechanical stability is reached in the maturation phase. These findings can potentially be implemented into treatment and aftercare protocols.

Strength Measurement After Achilles Tendon Repair

The goal of treatment after Achilles tendon rupture (ATR) is to restore appropriate tension to the tendon, so that normal baseline strength and functional soft-tissue length can be achieved. The assessment of plantarflexion strength has shown widespread variability. The purpose of this study is to document variations in strength assessment after the treatment of ATR in the literature. A comprehensive literature review was performed. In total, 2758 articles were found on Achilles tendon rupture and Achilles tendon strength measurement. The full text of articles including strength as a functional outcome measurement in the abstract were assessed. All objective strength measurements performed were reviewed and recorded for comparison. One-hundred articles were included in our study. In 78 articles, a dynamometer was used to measure strength, whereas in 22 articles, an endurance test (n=14) or formal gait assessment (n=8) was applied. When a dynamometer was used, there was wide variability in the various methods used including the incorporation of both isokinetic (n = 65) and isometric (n = 29) exercises utilizing varying degrees of knee flexion and patient testing position. Furthermore, the number of measurements at certain angular velocities varied. This study illustrates that no general consensus exists regarding an optimal method for measuring strength after ATR. The variability creates difficulty and challenges medical professionals' ability to formulate consistent conclusions when determining functional performance outcomes. A more uniform way of measuring strength after ATR may allow for better comparisons between studies in the literature, potentially leading to a better understanding of strength. Levels of Evidence: Therapeutic, Level II.

Long-Term Results With the Use of Modified Percutaneous Repair of the Ruptured Achilles Tendon Under Local Anaesthesia (15-Year Analysis With 270 Cases)

Controversy regarding the optimal treatment of fresh total Achilles tendon rupture remains. This article presents results with the use of modified percutaneous Achilles tendon repair under local anesthesia performed from January 1991 to December 2005 with a 2- to 10-year follow-up. There were 270 procedures in 247 male patients (92.51%) and 20 female patients (7.49%), mean ± SD age 38.7 ± 11.56 (range 20 to 83) years, in all consecutively treated patients within 7 days after acute total rupture; 3 patients sustained ruptures on both sides in different periods. Postoperative care consisted of wearing a cast or soft cast or functional immobilization for 6 weeks. The procedure was well tolerated in all patients. There were 3 (1.11%) complete and 5 (1.85%) partial repeat ruptures (8 [2.96%] altogether). Fourteen patients (5.18%) developed transient sural neuritis that spontaneously resolved in 2 to 10 months. One case (0.3%) of deep venous thrombosis was successfully treated. There were 25 (9.36%) major and minor complications altogether, with no cases of increased postoperative dorsiflexion, deep infection, or necrosis. Forty-four patients (16.48%) had a slightly decreased range of ankle motion, and 216 (80.89%) patients, including all high-caliber athletes, resumed all their previous activities. The mean American Orthopedic Foot and Ankle Society hindfoot-ankle score was 96.10 points. Long-term results of the analyzed modified method suggest a reasonable treatment option for acute total Achilles tendon ruptures, with a low number of complications and repeat rupture rate and return to preinjury activities comparable to those of open procedures.

Achilles tendon elastic properties remain decreased in long term after rupture

PURPOSE

Rupture of the Achilles tendon results in inferior scar tissue formation. Elastography allows a feasible in vivo investigation of biomechanical properties of the Achilles tendon. The purpose of this study is to investigate the biomechanical properties of healed Achilles tendons in the long term.

MATERIALS AND METHODS

Patients who suffered from Achilles tendon rupture were recruited for an elastographic evaluation. Unilateral Achilles tendon ruptures were included and scanned in the mid-substance and calcaneal insertion at least 2 years after rupture using shear wave elastography. Results were compared to patients' contralateral non-injured Achilles tendons and additionally to a healthy population. Descriptive statistics, reliability analysis, and correlation analysis with clinical scores were performed.

RESULTS

Forty-one patients were included in the study with a mean follow-up-time of 74 ± 30; [26-138] months after rupture. Significant differences were identified in shear wave elastography in the mid-substance of healed tendons (shear wave velocity 1.2 ±1.5 m/s) compared to both control groups [2.5 ±1.5 m/s (p < 0.01) and 2.8 ±1.6 m/s (p < 0.0001) contralateral and healthy population, respectively]. There was no correlation between the measurements and the clinical outcome.

CONCLUSIONS

This study shows that the healed Achilles tendon after rupture has inferior elastic properties even after a long-term healing phase. Differences in elastic properties after rupture mainly originate from the mid-substance of the Achilles tendon, in which most of the ruptures occur. Elastographic results do not correspond with subjective perception. Clinically, sonoelastographical measurements of biomechanical properties can be useful to provide objective insights in tendon recovery.

Mini open versus open repair techniques in Achilles tendon rupture: clinical and isokinetic evaluation

Background

The aim of the study was to compare the mini-open to the classic open repair techniques for Achilles tendon ruptures.

Methods

We retrospectively evaluated at a minimum of 2 years follow-up 32 subcutaneous Achilles tendon ruptures; 17 underwent mini-open surgery (Group A) and 15 the open technique (Group B).

Results

No difference in Achilles Tendon Total Rupture Score and in modified Leppillahti score was observed. With respect to the contralateral side the width of the operated Achilles tendon was 4.07 mm thicker in Group A and 7.67 mm in Group B (p<.05); the calf circumference reduction was respectively 10 mm and 23.75 mm (p<.05). Iso-kinetic peak force measurement of the calf muscle strength showed a loss of 8.21% in Group A versus 17.25% in Group B (p <.05). The mean Patient Satisfaction Score was 96.76 in Group A and 88.67 in Group B (p<.01); respectively 82.3% vs 66.7% of patients were able to return to previous levels of sporting activity. There were two post-operative complications in Group B and one in Group A.

Conclusion

Mini-open technique minimizes the risk of complications, leads to an improved tendon healing process and functional recovery with higher patient satisfaction.

Level of evidence

IV.

Myotonometry Reliably Measures Muscle Stiffness in the Thenar and Perineal Muscles

Purpose: The authors investigated the reliability of myotonometry-measured muscle tone in the thenar and perineal muscles. Methods: Participants were women aged 18-50 years who were asymptomatic for thumb and pelvic floor dysfunction (interrater study n=20; intrarater study n=43) or who were symptomatic for vulvodynia (interrater study n=14; intrarater study n=32). Mechanical properties (stiffness, frequency, decrement, relaxation time, and creep) of the muscles were measured using a myotonometer (MyotonPRO) while the muscles were in a relaxed state. Measures were performed twice by two assessors. Intra- and interrater reliability were determined using intra-class correlation coefficients (ICCs) and absolute reliability using the standard error of measurement and a minimum detectable change. Results: The primary property of interest, muscle stiffness, showed very good interrater (ICC 0.85-0.86) and intrarater (ICC 0.82-0.88) reliability in the thenar eminence. In the perineal muscles, reliability results ranged from good to very good for interrater (ICC 0.70-0.86) and intrarater (ICC 0.80-0.91) reliability for muscle stiffness. Absolute reliability was confirmed, with all measures showing minimal variance. Conclusions: Muscle stiffness of the smaller muscles of the body can be reliably measured using the MyotonPRO. The device could be used as a reference standard in the development of a digital palpation scale that would facilitate accurate diagnosis of muscle tone.

Passive stiffness of the ankle and plantar flexor muscle performance after Achilles tendon repair: a cross-sectional study

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The surgical ankle presented lower stiffness values than the non-surgical ankle in the same subject.

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The surgical ankle presented lower stiffness than the non-surgical group.

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The SU group had greater absolute asymmetry of ankle stiffness.

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The SU group had greater absolute asymmetry of plantar flexor muscle work.

Background

Deficits in ankle muscle strength and ankle stiffness may be present in those subjects who underwent surgical treatment for an Achilles tendon rupture. The presence of these long-term deficits may contribute to a lower performance during daily activities and may be linked to future injuries.

Objective

To compare the ankle passive stiffness and the plantar flexor muscle performance in patients who underwent unilateral surgical treatment of Achilles tendon rupture with nonsurgical subjects.

Method

Twenty patients who underwent unilateral surgical treatment of Achilles tendon rupture [surgical (SU) group], and twenty nonsurgical subjects [non-surgical (NS) group] participated in this study. The ankle passive stiffness was evaluated using a clinical test. The concentric and eccentric plantar flexors performance (i.e. peak torque and work) was evaluated using an isokinetic dynamometer at 30°/s.

Results

The surgical ankle of the surgical group presented lower stiffness compared to the non-surgical ankle (mean difference = 3.790; 95%CI = 1.23–6.35) and to the non-dominant ankle of the non-surgical group (mean difference = −3.860; 95%CI = −7.38 to −0.33). The surgical group had greater absolute asymmetry of ankle stiffness (mean difference = −2.630; 95%CI = −4.61 to −0.65) and greater absolute asymmetry of concentric (mean difference = −8.3%; 95%CI = −13.79 to −2.81) and eccentric (mean difference = −6.9%; 95%CI = −12.1 to −1.7) plantar flexor work compared to non-surgical group. There was no other difference in stiffness and plantar flexor performance.

Conclusion

Patients who underwent surgical repair of the Achilles tendon presented with long-term (1 year or more) deficits of ankle stiffness and asymmetries of ankle stiffness and plantar flexor work in the affected ankle compared to the uninjured side in the surgical group and both sides on the nonsurgical group.

The structural and mechanical properties of the Achilles tendon 2 years after surgical repair

BACKGROUND

Acute ruptures of the Achilles tendon affect the tendon's structural and mechanical properties. The long-term effects of surgical repair on these properties remain unclear.

PURPOSE

To evaluate effects of early mobilization versus traditional immobilization rehabilitation programs 2 years after surgical Achilles tendon repair, by comparing force-elongation and stress-strain relationships of the injured tendon to those of the uninjured tendon.

METHODS

A group of males with previous Achilles tendon rupture (n=18) and a group of healthy male controls (n=9) participated. Achilles tendon rupture group consisted of patients that had received early mobilization (n=9) and patients that had received traditional immobilization with a plaster cast (n=9). Comparisons of tendon structural and mechanical properties were made between Achilles tendon rupture and healthy control groups, and between the uninjured and injured sides of the two rehabilitation groups in Achilles tendon rupture group. Ultrasound was used to determine bilaterally tendon cross-sectional area, tendon resting length, and tendon elongation as a function of torque during maximal voluntary plantar flexion. From these data, Achilles tendon force-elongation and stress-strain relationships were determined.

FINDINGS

The Achilles tendon rupture group uninjured side was not different from healthy control group. Structural and mechanical parameters of the injured side were not different between the Achilles tendon rupture early mobilization and the immobilization groups. Compared to the uninjured side, the injured side showed a reduction in stress at maximal voluntary force, in Young's modulus and in stiffness.

INTERPRETATION

Two years post-surgical repair, the Achilles tendon mechanical properties had not returned to the uninjured contralateral tendon values.

Nonoperative, dynamic treatment of acute achilles tendon rupture: influence of early weightbearing on biomechanical properties of the plantar flexor muscle-tendon complex-a blinded, randomized, controlled trial

Acute Achilles tendon rupture alters the biomechanical properties of the plantar flexor muscle-tendon complex that can affect functional performance and the risk of repeat injury. The purpose of the present study was to compare the biomechanical properties of the plantar flexor muscle-tendon complex in patients randomized to early weightbearing or non-weightbearing in the nonoperative treatment of Achilles tendon rupture. A total of 60 patients were randomized to full weightbearing from day 1 of treatment or non-weightbearing for 6 weeks. After 6 and 12 months, the peak passive torque at 20° dorsiflexion, the stiffness during slow stretching, and the maximal strength were measured in both limbs. The stiffness of the plantar flexor muscle-tendon complex in the terminal part of dorsiflexion was significantly increased (p = .024) in the non-weightbearing group at 12 months. The peak passive torque was significantly lower for the affected limb at 6 months (91%; p = .01), and the stiffness was significantly lower for the affected limb during the early part of dorsiflexion at 6 (67%; p < .001) and 12 (77%; p < .001) months. In conclusion, an increased stiffness of the plantar flexor muscle-tendon complex in the terminal part of dorsiflexion was found in the non-weightbearing group. The altered stiffness and strength in the affected limb could affect the coordination of gait and running.

Mini-open tenorrhaphy of acute Achilles tendon ruptures: medium-term follow-up of 100 cases

BACKGROUND

The high incidence of soft tissue complications related to open Achilles repair has driven enthusiasm for developing minimally invasive surgical procedures. The Dresden procedure, which reduces wound-healing issues and avoids sural nerve damage, has recently been published and shows good functional results.

OBJECTIVE

To evaluate medium-term clinical results of procedures using the Dresden mini-open technique on acute Achilles tendon ruptures.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective analysis was performed on 100 consecutive patients with a mean follow-up of 42.1 months. At follow-up, the American Orthopaedic Foot and Ankle Society (AOFAS) score, time to return to work and sports, subjective satisfaction, and complications were registered. An isokinetic test was performed on the first 21 patients of this series at 1 year postoperatively.

RESULTS

The mean time to return to work was 56.0 days, and the mean time to return to sports was 18.9 weeks. The mean AOFAS score was 97.7; 98% of patients were satisfied. No complications regarding soft tissues and sural nerve damage were reported. Two reruptures and 5 cases of deep venous thrombosis were observed. The isokinetic evaluation showed good recovery of the involved muscles.

CONCLUSION

The excellent functional and satisfaction results, ease of the procedure, and avoidance of sural nerve damage make the mini-open technique a very attractive alternative for acute, spontaneous Achilles tendon ruptures.

Effects of peripheral injury in athletes with long-term-exercise participation in modern pentathlons

This study was conducted to verify the effect of the ankle injury of athletes who attended the modern pentathlon for a long-term basis on ankle muscle’s strength and proprioceptive sensory function. For this, 10 athletes of the modern pentathlon, with experience of having damaged one side of their ankles within 6 months, and 10 healthy male college students, who have similar personal characteristics, such as height, age, and weight and have no experience of participating in regular sports for 3 or more times a week. The experimental subject was divided into 3 groups in all. After the flexor power of the plantar and dorsal side and the muscle strength of the varus and valgus for an ankle were measured by the Biodex System III at an angular velocity of 60°/sec and 120°/sec, it was documented as the maximum couple of force per body weight. Also, specified receptive senses were measured by the Biodex System III using the stop button to find the position (angle) of the joint. As a result of the conclusive research, participation in modern pentathlons for a long-term basis has caused an increase in valgus muscle strength and flexor power of the plantar side of the ankle when compared to general college students. Sports-related injury of the ankle was also found to result into the weakening of the flexor power on the plantar side and valgus muscle strength and a decrease of the proprioceptive sensory function.

Three-Dimensional Gait Analysis Following Achilles Tendon Rupture With Nonsurgical Treatment Reveals Long-Term Deficiencies in Muscle Strength and Function

Background:

Precise long-term assessment of movement and physical function following Achilles tendon rupture is required for the development and evaluation of treatment, including different regimens of physical therapy.

Purpose:

To assess intermediate-term (<10 years by conventional thinking) objective measures of physical function following Achilles tendon rupture treated nonsurgically and to compare these with self-reported measures of physical function.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Two to 5 years after Achilles tendon rupture, 9 women and 43 men (mean age, 49.2 years; range, 26-68 years) were assessed by physical examination, performance of 1-legged jumps, and 3-dimensional gait analysis (including calculation of muscle work). Self-reported scores for foot function (Achilles tendon rupture score) and level of physical activity were collected. Twenty age- and sex-matched controls were assessed in the same manner.

Results:

Physical examination of patients with the knee extended revealed 11.1° of dorsiflexion on the injured side and 9.2° on the uninjured side (P = .020), indicating gastrocnemius muscle lengthening. The 1-legged jump distance was shorter on the injured side (89.5 vs 96.2 cm; P < .001). Gait analysis showed higher peak dorsiflexion (14.3° vs 13.3°; P = .016) and lower concentric (positive) plantar flexor work (16.6 vs 19.9 J/kg; P = .001) in the ankle on the uninjured side. At the same time, eccentric (negative) dorsiflexor work was higher on the injured side (13.2 vs 11.9 J/kg; P = .010). Self-perceived foot function and physical activity were lower in patients than in healthy controls (mean Achilles tendon rupture score, 78.6 and 99.8, respectively).

Conclusion:

Nonsurgically treated patients with Achilles tendon rupture showed signs of both anatomic and functional lengthening of the tendon. Attenuated muscle strength and function were present during walking as long as 2 to 5 years after rupture, as determined by 3-dimensional gait analysis. More extensive future studies involving patients having both surgical and nonsurgical treatment could provide additional valuable information.

Biomechanical properties of the plantar flexor muscle-tendon complex 6 months post-rupture of the Achilles tendon

We compared the effects of a non-weight bearing protocol (NWB) and a weight bearing (WB) protocol on energy stored, stiffness, and shock absorption in the plantar flexor muscle-tendon unit of patients managed non-operatively following an Achilles tendon rupture. Thirty-eight subjects were randomized to a WB cast fitted with a Bohler iron or a traditional non-weight-bearing cast. At a 6-month follow-up, a biomechanical assessment utilizing an isokinetic dynamometer allowed measurement of peak passive torque, energy stored, shock absorption, and stiffness. The WB group had greater peak passive torque (≈ 20%). Irrespective of group, peak passive torque in unaffected legs was greater (≈ 26%) than affected legs. Across the groups, energy stored in the NWB group was 74% of the WB group. The energy stored in affected legs was 80% of that in unaffected legs. Shock absorption was not significantly different across legs or groups. Irrespective of group, affected legs had significantly less stiffness (20-40%). While the augmentation of plaster with a Bohler iron to allow increased weight bearing had positive effects, deficits in affected compared to unaffected legs irrespective of group were notable, and should be addressed prior to participation in vigorous physical activities.

Physiological Achilles tendon length and its relation to tibia length

OBJECTIVE

The optimal intraoperative Achilles tendon length (ATL) adjustment is crucial for the physiological functioning of the musculotendinous unit. To date, the resting ATL and its relation to tibia length (TL) have never been defined in healthy subjects. We thus performed metric measurements of the ATL and TL.

DESIGN

Case series.

SETTING

Clinical and radiological measurements.

PARTICIPANTS

Fifty-two subjects placed in a 3-T magnetic resonance imaging with the ankle in neutral position.

MAIN OUTCOME MEASURES

Unilateral ATL measured from the calcaneal insertion to the beginning of the medial gastrocnemius muscle, TL measured from the intercondylar eminence to the center of the ankle, and qualitative tendon parameters in T2 sequences and human parameters were noted; results were correlated with age, gender, body height, weight, body mass index (BMI), and side of the AT and TL.

RESULTS

The mean ATL was 180.6 ± 25.0 mm and the mean TL was 371.9 ± 25.4 mm with an ATL:TL ratio of 49 ± 5%. Achilles tendon length correlated significantly with body height (R = 38%, P < 0.0001) and with TL (R = 41%, P < 0.0001) but did not correlate with age, BMI, and side of the AT. Tibia length correlated with body height (R = 83%, P < 0.0001) and in multivariate linear regression, TL was the only independent predictor of ATL following the algorithm, ATL (mm) = 0.6 × TL (mm) - 53 (R = 41%).

CONCLUSIONS

We defined a new way to measure the ATL in a consistent way in healthy subjects and showed correlations between ATL, TL and body height and defined an algorithm of ATL based on TL. The ATL and the ATL-algorithm might be important in patients with impaired tendons such as AT ruptures.

A meta-analysis of randomised controlled trials comparing conventional to minimally invasive approaches for repair of an Achilles tendon rupture

Achilles tendon ruptures are a common injury afflicting predominantly the young male occasional sportsman. Previous studies have shown that outcome is better with surgical repair for the young active patient. There is no consensus as to whether there is a difference in outcome between open and percutaneous minimally invasive surgery (MIS). A meta-analysis was undertaken to compare the clinical outcomes of MIS with conventional open surgical repair. Six randomised controlled trials of 277 Achilles tendon repairs were eligible for review. This included 136 minimally invasive repairs and 141 conventional open repairs. On analysis, there was no significant difference between the two surgical approaches in respect to the incidence of re-rupture, tissue adhesion, sural nerve injury, deep infection and deep vein thrombosis (p>0.05). However, MIS had a significantly reduced risk of superficial wound infection, with three times greater patient satisfaction for good to excellent results compared with conventional open surgical approaches.

In-shoe plantar pressures within ankle-foot orthoses: implications for the management of achilles tendon ruptures

BACKGROUND

Advances in the management of Achilles tendon rupture have led to the development of immediate weightbearing protocols. These vary regarding which ankle-foot orthoses (AFOs) are used and the number of inserted heel wedges used within them.

PURPOSE

This study was conducted to evaluate plantar pressure measurements and temporal gait parameters within different AFOs, using different numbers of heel wedges.

STUDY DESIGN

Controlled laboratory study.

METHODS

Fifteen healthy participants were evaluated using 3 different AFOs, with 4 different levels of inserted heel wedges. Therefore, a total of 12 conditions were evaluated, in a sequence that was randomly allocated to each participant. Pressure and temporal gait parameters were measured using an in-shoe F-Scan pressure system, and range of movement was measured using an electrogoniometer.

RESULTS

Ankle-foot orthoses that were restrictive in design, combined with a higher number of inserted heel wedges, reduced forefoot pressures, increased heel pressures, and decreased the amount of time spent in the terminal stance and preswing phase of the gait cycle (P = .029, .002, and .001).

CONCLUSION

The choice of AFO design and the number of inserted heel wedges have a significant effect on plantar pressure measurements and temporal gait parameters. The implications of these changes need to be applied to the clinical management of acute Achilles tendon ruptures. This clinical management requires a balance between protected weightbearing and functional loading, requiring further research within a clinical context.

CLINICAL RELEVANCE

The biomechanical data from this research imply that a carbon-fiber AFO, with 1 heel raise, protects against excessive dorsiflexion while facilitating the restoration of near-normal gait parameters. This could lead to an accelerated return to function, avoiding the effects of disuse atrophy. This is in contrast to the rigid rocker-bottom AFO design with a greater number of heel-wedge inserts. However, research within a clinical context would be required to ascertain if these biomechanical advantages translate into a functional benefit for patients. The results should also be considered in relation to the amount of force a healing Achilles tendon can withstand.

Morphology of hamstring torque-time curves following ACL injury and reconstruction: mechanisms and implications

The purposes of this study were (i) to examine the effects of anterior cruciate ligament (ACL) status on hamstring force steadiness, peak hamstring strength, quadriceps (antagonist) activation, and physical performance, and (ii) to evaluate the associations of physical performance with hamstring steadiness and hamstring strength. Thirteen subjects with unilateral deficiency of the ACL (ACLD), 39 matched subjects with unilateral reconstructed ACL (ACLR; n = 25 with bone-patella tendon-bone (ACLR-PT) graft and n = 14 with combined semitendinosus and gracilis tendon (ACLR-STGT) graft) and 33 control subjects participated. Each subject performed maximal-effort isokinetic knee flexion repetitions at 180° s(-1) with electromyography (EMG) electrodes attached to their medial and lateral quadriceps muscles. Physical performance was assessed using the single-limb long hop for distance. Wavelet-derived mean instantaneous frequency (Mif) of flexor torque-time curves was significantly (p < 0.05) higher (i.e., less smooth) in ACLR-STGT subjects compared to the ACLD, ACLR-PT and control subjects. No significant differences existed for peak hamstrings strength (i.e., peak torque produced) or quadriceps antagonist EMG activity. Positive correlations were identified between hamstrings force steadiness and quadriceps antagonist activity for ACLD (r =  0.797), ACLR-PT (r = 0.467), and ACLR-STGT (r = 0.628) subjects. For ACLR-STGT subjects, reduced hamstrings force steadiness associated with poorer long-hop performance (r = -0.695). Reduced steadiness amongst ACLR-STGT subjects may reflect motor output variability of the antagonist (i.e., quadriceps dyskinesia) and/or agonist musculature-a maladaptive feature which potentially contributes to poorer single-limb hop performance. Measures of hamstring force steadiness in combination with traditional measures of peak hamstring strength provide valuable clinical information regarding knee joint function following ACL injury/ACLR.

The influence of early weight-bearing compared with non-weight-bearing after surgical repair of the Achilles tendon

BACKGROUND

The optimal rehabilitation protocol after surgical repair of an Achilles tendon rupture has not been well defined. The objective of this randomized study was to compare the effect of early weight-bearing with that of non-weight-bearing on early postoperative recovery following repair of an acutely ruptured Achilles tendon.

METHODS

Between October 2003 and May 2006, 110 patients with a surgically repaired Achilles tendon rupture were enrolled from one of two major trauma-care tertiary hospitals. All patients were non-weight-bearing for the first two weeks postoperatively. At the two-week postoperative visit, patients were randomized to either weight-bearing or non-weight-bearing for an additional four weeks. Compliance was measured with a pressure sensor in the fixed-hinge ankle-foot orthosis given to each patient. Follow-up assessments were performed at six weeks, three months, and six months postoperatively. The primary outcome was health-related quality of life assessed with use of the RAND 36-Item Health Survey (RAND-36). Secondary outcomes were activity level, calf strength, ankle range of motion, return to sports and work, and complications.

RESULTS

Ninety-eight patients (89%) completed the six-month follow-up. At six weeks, the weight-bearing group had significantly better scores than the non-weight-bearing group in the RAND-36 domains of physical functioning, social functioning, role-emotional, and vitality scores (p < 0.05). Patients in the weight-bearing group also reported fewer limitations of daily activities at six weeks postoperatively (p < 0.001). At six months, no significant differences between the groups were seen in any outcome, although both groups had poor endurance of the calf musculature. No rerupture occurred in either group.

CONCLUSIONS

Early weight-bearing after surgical repair of an acute Achilles tendon rupture improves health-related quality of life in the early postoperative period and has no detrimental effect on recovery.

Mechanical evaluation of different techniques for Achilles tendon repair

INTRODUCTION

One aim of the surgical treatment of acute Achilles tendon ruptures is to obtain a maximum primary stability of the sutured tendon. Therefore, we investigated the primary stability of sutured human Achilles tendons depending on different applied techniques.

METHODS

The strength of 60 repaired cadaveric human Achilles tendons was tested depending on either the suture technique (Bunnell or Kessler), the suture material (PDS-thread or PDS-cord) or an additional plantaris tendon augmentation (PDS-thread with or without augmentation). Following anatomic reconstruction the repaired specimens were loaded to failure.

RESULTS

The use of Bunnell's technique resulted in a stronger primary suture stability compared to Kessler's technique. Sutures carried out with a PDS-thread were of lower strength than those accomplished with a PDS-cord (Bunnell: thread 139 N +/- 29.8; cord 291 N +/- 55.2/Kessler: thread 137 N +/- 37.3; cord 180 N +/- 41.1). Sutures performed according to Bunnell's technique with a PDS-thread and an additional autologous plantaris tendon augmentation reached the highest primary stability (326 N +/- 124.9).

CONCLUSIONS

The findings identify the Achilles tendon suture with a PDS-cord according to Bunnell's technique as a mechanically strong method. A plantaris tendon augmentation in addition to a PDS-thread can even add more stability to the Achilles tendon suture.

Effect of Static and Ballistic Stretching on the Muscle-Tendon Tissue Properties

PURPOSE

Many studies have been undertaken to define the effects of static and ballistic stretching. However, most researchers have focused their attention on joint range-of-motion measures. The objective of the present study was to investigate whether static- and ballistic-stretching programs had different effects on passive resistive torque measured during isokinetic passive motion of the ankle joint and tendon stiffness measured by ultrasound imaging.

METHODS

Eighty-one healthy subjects were randomized into three groups: a static-stretch group, a ballistic-stretch group, and a control group. Both stretching groups performed a 6-wk stretching program for the calf muscles. Before and after this period, all subjects were evaluated for ankle range of motion, passive resistive torque of the plantar flexors, and the stiffness of the Achilles tendon.

RESULTS

The results of the study reveal that the dorsiflexion range of motion was increased significantly in all groups. Static stretching resulted in a significant decrease of the passive resistive torque, but there was no change in Achilles tendon stiffness. In contrast, ballistic stretching had no significant effect on the passive resistive torque of the plantar flexors. However, a significant decrease in stiffness of the Achilles tendon was observed in the ballistic-stretch group.

CONCLUSION

These findings provide evidence that static and ballistic stretching have different effects on passive resistive torque and tendon stiffness, and both types of stretching should be considered for training and rehabilitation programs.

Relationship between recovery of calf-muscle biomechanical properties and gait pattern following surgery for achilles tendon rupture

BACKGROUND

The relationship between ankle plantar flexor biomechanical properties and gait pattern following surgery for acute rupture of the Achilles tendon has not yet been fully investigated.

METHODS

Forty-nine young adults (27 men and 22 women) who underwent surgical repair of a complete Achilles tendon rupture were evaluated at 3, 6, 12 and 24 months by clinical assessment, biomechanical evaluation and gait analysis.

FINDINGS

Ankle range of motion, plantar flexor passive stiffness and concentric strength were recovered within 12 months. Gait abnormalities related to these factors took longer to disappear owing to the presence of anomalous muscle patterns. At 24 months, a deficit in calf-muscle eccentric strength was still present, determining adaptive changes in gait strategy that involved ankle motion and coordinated muscular activity.

INTERPRETATION

Improvement of gait pattern is slower than recovery of plantar flexor mechanical properties. Persisting mechanical impairment resulting in gait adaptations may be detrimental to the healing structures by increasing stress on the Achilles tendon. Restoration of calf-muscle eccentric strength and coordinated antagonist muscle activity should be key points in postoperative rehabilitation following surgical repair of Achilles tendon rupture.

Bilateral Achilles tendon rupture: a case report

Bilateral Achilles tendon rupture is a rare injury. We present a case of a 59-year-old gentleman who sustained a bilateral Achilles tendon rupture when the tendon was subjected to normal physiological load. He was treated operatively with V-Y plasty and repair of the tendon with post-operative plaster immobilisation.

An outcome study of chronic Achilles tendinosis after excision of the Achilles tendon and flexor hallucis longus tendon transfer

BACKGROUND

A number of operative techniques, including decompression with debridement and flexor hallucis longus (FHL) tendon augmentation, have been described for chronic degenerative Achilles tendinosis. Decompression with debridement has been shown to be effective; however, pain and functional limitation can persist in individuals with more severe tendon involvement. Augmentation with the FHL tendon can add mechanical support; however, difficulty in achieving proper tendon tensioning and the potential to leave behind painful diseased tendon are disadvantages of the technique. The purpose of this study was to present the results of a modified technique in which the Achilles tendon is completely excised and the FHL tendon is transferred.

METHODS

Fifty-six surgeries using this modified technique were done between October, 1994, and March, 2002, for patients with chronic degenerative Achilles tendinosis. Forty-four patients with and average age of 58.2 (SD 10.1) years and an average time of followup of 3.4 (SD 1.9) years were available for testing. All subjects were mailed a packet of standardized questionnaire information that included the Self-Reported Health Related Quality of Life measures Short Form (SF-36) and the subjective component of the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle and Hindfoot Score. Nineteen patients returned to the clinic for objective assessment. Statistical analysis tested for a difference in the SF-36 scores between our subjects and the general United States population and for a difference in strength and range of motion between the involved and uninvolved lower extremities.

RESULTS

Pain decreased in 95.5% (n = 42) patients, and 86.4% (n = 38) patients were satisfied with the result. There was no significant difference (p > .05) between the SF-36 scores obtained by our sample compared to the general United States population. The average AOFAS score for the 19 patients was 91.6 (SD 7.7). Dorsiflexion range of motion was not significantly different (p = 0.17); however, significant deficits were found in plantarflexion range of motion (p = 0.001) and plantarflexion strength (p < 0.025). Strength deficits were 30% on average; however, all but one patient could do a heel raise.

CONCLUSION

Complete Achilles tendon excision reduces pain while preserving functional status. Although strength deficits persisted, these deficits did not seem to affect the functional status in this sample of patients.

Isokinetic strength and endurance after percutaneous and open surgical repair of Achilles tendon ruptures

BACKGROUND

Reports on complete spontaneous Achilles tendon ruptures and associated treatment have become more frequent in the literature in the past two decades, as has the request for treatments that enable the finest possible functional recovery. The best available treatment is a matter of considerable controversy in the literature. The purpose of this study was to compare the isokinetic strength and endurance of the plantarflexor muscle-tendon unit in subjects who sustained rupture of the Achilles tendon and underwent either open surgery or closed percutaneous repair of the Achilles tendon.

METHODS

Twenty patients (18 males, 2 females) with spontaneous ruptures of the Achilles tendon were included in this study. Ten patients were treated by open surgery, and 10 patients were treated percutaneously. All patients had ruptured their Achilles tendon more than 6 months before the study, and all of the ruptures occurred 3.5 years or less before the day of the testing. All patients underwent an oriented physical examination. An isokinetic Biodex dynamometer (Biodex Medical System, Shirley, NY) was used to measure ankle joint angle, and in plantarflexion to calculate the torque at the ankle joint (Newton/meter), and the average work (jouls) for both maximal power and endurance. Each measurement was compared to the normal ankle.

RESULTS

Biodex dynamometer evaluations at 90 deg/sec demonstrated a significant difference of maximal voluntary plantarflexor torque, endurance performance and range of motion at the ankle joint between the involved and uninvolved sides in patients treated by either mode of treatment. Yet, no statistically significant differences were revealed for the parameters mentioned above between the subjects that were treated either percutaneously or by an open surgery.

CONCLUSIONS

In functional terms, the biomechanical outcomes of open surgery and percutaneous repair for acute ruptures of the Achilles tendon are both effective.

Functional efficacy of tendon repair processes

Despite various attempts to repair and replace injured tendon, an understanding of the repair processes and a systematic approach to achieving functional efficacy remain elusive. In this review the epidemiology of tendon injury and repair is first examined. Using a traditional paradigm for repair assessment, the biology and biomechanics of normal tendon, natural healing, and repair are then explored. New treatment strategies such as functional tissue engineering are discussed, including a functional approach to treatment that involves the development of in vivo functional design parameters to judge the acceptability of a repair outcome. The paper concludes with future directions.

Ankle joint proprioception and passive mechanical properties of the calf muscles after an Achilles tendon rupture: a comparison with matched controls

OBJECTIVE

To examine if ankle joint proprioception, passive stiffness, and torque relaxation responses of the involved and uninvolved limbs of persons with a previous history of an Achilles tendon rupture were different from matched controls.

DESIGN

Quasi-experimental mixed design.

BACKGROUND

The influence of an Achilles tendon rupture on the proprioceptive and kinetic performance of the involved and uninvolved ankle is not known.

METHODS

Twenty persons (mean age, 44.8 years) with a unilateral rupture and 20 matched controls (mean age, 44.2 years) volunteered. Proprioception was tested with a position-matching protocol from which absolute errors were quantified. A dynamometer was used to measure ankle joint angle and passive torque from which stiffness and torque relaxation were calculated.

RESULTS AND CONCLUSIONS

Proprioception absolute errors for the involved and uninvolved limbs of the experimental group were 27% and 31% greater respectively, than values for the control group. Torque relaxation values were greater in the involved limb versus the uninvolved limb or the control group (P=0.003-0.04). In conclusion, participants with a previous history of an Achilles tendon rupture display proprioception deficits in both limbs and greater torque relaxation in the involved limb in comparison to matched controls.

RELEVANCE

Bilateral deficits in ankle joint proprioception, as reported in this study, suggest the uninvolved limb may not serve as an effective control and because proprioception deficits influence some functional tests, Achilles tendon rupture patients may benefit from proprioception training.

Diagnosis and Management of the Painful Ankle/Foot. Part 2: Examination, Interpretation, and Management

Diagnosis, interpretation, and subsequent management of ankle/foot pathology can be challenging to clinicians. A sensitive and specific physical examination is the strategy of choice for diagnosing selected ankle/foot injuries and additional diagnostic procedures, at considerable cost, may not provide additional information for clinical diagnosis and management. Because of a distal location in the sclerotome and the reduced convergence of afferent signals from this region to the dorsal horn of the spinal cord, pain reference patterns are low and the localization of symptoms is trustworthy. Effective management of the painful ankle/foot is closely linked to a tissue-specific clinical examination. The examination of the ankle/foot should include passive and resistive tests that provide information regarding movement limitations and pain provocation. Special tests can augment the findings from the examination, suggesting compromises in the structural and functional integrity of the ankle/foot complex. The weight bearing function of the ankle/foot compounds the clinician's diagnostic picture, as limits and pain provocation are frequently produced only when the patient attempts to function in weight bearing. As a consequence, clinicians should consider this feature by implementing numerous weightbearing components in the diagnosis and management of ankle/foot afflictions. Limits in passive motion can be classified as either capsular or non-capsular patterns. Conversely, patients can present with ankle/foot pain that demonstrates no limitation of motion. Bursitis, tendopathy, compression neuropathy, and instability can produce ankle/foot pain that is challenging to diagnose, especially when they are the consequence of functional weight bearing. Numerous non-surgical measures can be implemented in treating the painful ankle/foot, reserving surgical interventions for those patients who are resistant to conservative care.

Achilles tendinopathy

Achilles tendon injury (tendinopathy) and pain occur in active individuals, when the tendon is subject to high or unusual load. Achilles tendinopathy can be resistant to treatment, and symptoms may persist despite both conservative and surgical intervention. The pathology of overuse tendinopathy is non-inflammatory, with a degenerative or failed healing tendon response. The diagnosis of Achilles tendinopathy requires excellent differential diagnosis and an understanding of the role of tendon imaging. Conservative treatment must include exercise, with a bias to eccentric contractions. Surgical treatment is effective after complete tendon rupture, but may not assist recovery from overuse tendinopathy. Further research into the clinical aspects of Achilles tendinopathy is required.