Medial Gastrocnemius Myotendinous Junction Displacement and Plantar-Flexion Strength in Patients Treated With Immediate Rehabilitation After Achilles Tendon Repair

Exploration of muscle-tendon biomechanics one year after Achilles tendon rupture and the compensatory role of flexor hallucis longus

Achilles tendon (AT) rupture leads to long-term structural and functional impairments. Currently, the predictors of good recovery after rupture are poorly known. Thus, we aimed to explore the interconnections between structural, mechanical, and neuromuscular parameters and their associations with factors that could explain good recovery in patients with non-surgically treated AT rupture. A total of 35 patients with unilateral rupture (6 females) participated in this study. Muscle-tendon structural, mechanical, and neuromuscular parameters were measured 1-year after rupture. Interconnections between the inter-limb differences (Δ) were explored using partial correlations, followed by multivariable linear regression to find associations between the measured factors and the following markers that indicate good recovery: 1) tendon length, 2) tendon non-uniform displacement, and 3) flexor hallucis longus (FHL) normalized EMG amplitude difference between limbs. Δmedial gastrocnemius (MG) (β = -0.12, p = 0.007) and Δlateral gastrocnemius (β = -0.086, p = 0.030) subtendon lengths were associated with MG tendon Δstiffness. MG (β = 11.56, p = 0.003) and soleus (β = 2.18, p = 0.040) Δsubtendon lengths explained 48 % of variance in FHL EMG amplitude. Regression models for tendon length and non-uniform displacement were not significant. Smaller inter-limb differences in Achilles subtendon lengths were associated with smaller differences in the AT stiffness between limbs, and a smaller contribution of FHL muscle to the plantarflexion torque. In the injured limb, the increased contribution of FHL appears to partially counteract a smaller contribution from MG due to the elongated tendon, however the role of FHL should not be emphasized during rehabilitation to allow recovery of the TS muscles.

A systematic review of the patient reported outcome measures utilized in level 1 randomized controlled trials involving achilles tendon ruptures

BACKGROUND

Patient Reported Outcome Measures (PROMs) are utilized in level 1 randomized controlled trials involving Achilles tendon ruptures. However, the characteristics of these PROMs and current practices has not yet been reported. We hypothesize that there will be heterogeneous PROM usage in this context.

METHODS

A PubMed and Embase systematic review was performed including all dates up to July 27th, 2022, assessing Achilles tendon ruptures in level 1 studies using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines where applicable. Inclusion criteria were all randomized controlled clinical studies involving Achilles tendon injuries. Studies that: (1) were not level 1 evidence (including editorial, commentary, review, or technique articles), (2) omitted outcome data or PROMs, (3) included injuries aside from Achilles tendon ruptures, (4) involved non-human or cadaveric subjects, (5) were not written in English, and (6) were duplicates were excluded. Demographics and outcome measures were assessed in the studies included for final review.

RESULTS

Out of 18,980 initial results, 46 studies were included for final review. The average number of patients per study was 65.5. Mean follow up was 25 months. The most common study design involved comparing two different rehabilitation interventions (48 %). Twenty different outcome measures were reported including the Achilles tendon rupture score (ATRS) (48 %), followed by the American Orthopedic Foot and Ankle score Ankle-Hindfoot score (AOFAS-AH) (46 %), the Leppilahti score (20 %), and the RAND-36/Short Form (SF) - 36/SF-12 scores (20 %). An average of 1.4 measures were reported per study.

CONCLUSION

Significant heterogeneity exists in PROM usage among level 1 studies involving Achilles tendon ruptures, which prevents meaningful interpretation of these data across multiple studies. We advocate for usage of at least the disease-specific Achilles Tendon Rupture score and a global, quality of life (QOL) survey such as the SF-36/12/RAND-36. Future literature should provide more evidence-based guidelines for PROM usage in this context.

LEVEL OF EVIDENCE

Level IV; Systematic Review.

Distal overactivation of gastrocnemius medialis in persistent plantarflexion weakness following Achilles tendon repair

Structural alterations of the triceps surae and Achilles tendon (AT) can promote plantarflexion weakness one-year following an AT repair, influencing the activation strategies of the Gastrocnemius Medialis (GM) muscle. However, this is yet to be demonstrated. We aimed to determine whether patients with plantar flexion weakness one-year after AT repair show altered GM spatial activation. In this cross-sectional and case-control study, ten middle-aged men (age 34 ± 7 years old, and 12.9 ± 1.1 months post-surgery) with a high AT total rupture score who attended conventional physiotherapy for six months after surgery, and ten healthy control men (age 28 ± 9 years old), performed maximal and submaximal (40, 60 and 90%) voluntary isometric plantarflexion contractions on a dynamometer. The peak plantar flexor torque was determined by isokinetic dynamometry and the GM neuromuscular activation was measured with a linear surface-electromyography (EMG) array. Overall EMG activation (averaged channels) increased when the muscle contraction levels increased for both groups. EMG spatial analysis in AT repaired group showed an increased activation located distally at 85-99%, 75-97%, and 79-97% of the electrode array length for 40%, 60%, and 90% of the maximal voluntary isometric contractions, respectively. In conclusion, patients with persistent plantar flexion weakness after AT rupture showed higher distal overactivation in GM.

Rehabilitation following operative treatment of acute Achilles tendon ruptures: a systematic review and meta-analysis

Purpose

Methods

Results

Conclusion

Do the heel-rise test and isometric strength improve after Achilles tendon repair using Dresden technique?

BACKGROUND

Achilles' tendon ruptures result in impaired plantar flexion strength and endurance. It is interesting to know the plantar flexion strength, the number of heel-rise repetitions, and the maximal calf circumference following Achilles' tendon ruptures repair.

METHODS

Both the injured and non-injured legs of thirty male patients with Achilles' tendon ruptures treated with the percutaneous Dresden technique were compared with the ankle function of 30 healthy participants. Rehabilitation involved partial weight-bearing for three weeks and then increased to full weight-bearing and ankle exercises.

RESULTS

The injured legs had weaker plantar flexion strength (1.64 ± 0.17 Nm/kg) compared with the non-injured legs (1.91 ± 0.24 Nm/kg; p = 0.002) and the healthy participants' legs (1.93 ± 0.32 Nm/kg; p < 0.001). The non-injured leg had greater ability in doing heel-rise repetitions (39.4 ± 6.1 rep.) compared with the injured legs (37.2 ± 5.7 rep.; p < 0.023) and the healthy participants' legs (31.0 ± 13.0 rep.; p < 0.001).

CONCLUSIONS

The injured leg had not recovered full isometric strength but had improved heel-rise repetition.

Postoperative Rehabilitation Following Achilles Tendon Repair: A Systematic Review

The optimal postoperative management of Achilles tendon (AT) rupture remains unknown. The past 2 decades have witnessed a trend toward less rigid immobilization, earlier weightbearing, and accelerated functional rehabilitation postoperatively. The objective of this study was to identify all high-quality studies pertaining to rehabilitation after AT repair and characterize the various rehabilitation protocols that have been described. A systematic review of the English-language literature was performed according to PRISMA guidelines. All included studies represented level 1, 2, or 3 evidence and examined postoperative rehabilitation protocols following the repair of an acute AT rupture. A total of 1187 subjects were included. Surgical technique, rehabilitation protocol, and outcome assessment varied widely between studies. Early postoperative weightbearing with less rigid immobilization appears to accelerate short-term functional recovery. An aggressive rehabilitation program may also be advantageous in the short term, but further studies are needed to determine the long-term effects of these accelerated physical therapy and return-to-play protocols.

Non-uniform displacement within ruptured Achilles tendon during isometric contraction

The purpose of this study was investigate tendon displacement patterns in non-surgically treated patients 14 months after acute Achilles tendon rupture (ATR) and to classify patients into groups based on their Achilles tendon (AT) displacement patterns. Twenty patients were tested. Sagittal images of AT were acquired using B-mode ultrasonography during ramp contractions at a torque level corresponding to 30% of the maximal isometric plantarflexion torque of the uninjured limb. A speckle tracking algorithm was used to track proximal-distal movement of the tendon tissue at 6 antero-posterior locations. Two-way repeated measures ANOVA for peak tendon displacement was performed. K-means clustering was used to classify patients according to AT displacement patterns. The difference in peak relative displacement across locations was larger in the uninjured (1.29 ± 0.87 mm) than the injured limb (0.69 ± 0.68 mm), with a mean difference (95% CI) of 0.60 mm (0.14-1.05 mm, P < .001) between limbs. For the uninjured limb, cluster analysis formed 3 groups, while 2 groups were formed for the injured limb. The three distinct patterns of AT displacement during isometric plantarflexion in the uninjured limb may arise from subject-specific anatomical variations of AT sub-tendons, while the two patterns in the injured limb may reflect differential recovery after ATR with non-surgical treatment. Subject-specific tendon characteristics are a vital determinant of stress distribution across the tendon. Changes in stress distribution may lead to variation in the location and magnitude of peak displacement within the free AT. Quantifying internal tendon displacement patterns after ATR provides new insights into AT recovery.

Resistance Exercises in Early Functional Rehabilitation for Achilles Tendon Ruptures Are Poorly Described: A Scoping Review

OBJECTIVES

To (1) describe which resistance exercises are used in the first 8 weeks of treatment for acute Achilles tendon rupture and (2) assess the completeness of reporting of the exercise descriptions.

DESIGN

Scoping review.

LITERATURE SEARCH

We searched the MEDLINE, Embase, CINAHL, Cochrane Library, and Physiotherapy Evidence Database (PEDro) databases.

STUDY SELECTION CRITERIA

Randomized controlled trials, cohort studies, and case series (10 or more participants) that reported using resistance exercise in the immobilization period in the first 8 weeks of treatment for acute Achilles tendon rupture were included.

DATA SYNTHESIS

Completeness of exercise description was assessed with the Consensus on Exercise Reporting Template (CERT) and the Toigo and Boutellier exercise descriptor framework.

RESULTS

Thirty-eight studies were included. Fifty-one resistance exercises were extracted and categorized as isometric exercises (n = 20), heel raises (n = 6), strengthening with external resistance (n = 13), or unspecified (n = 12). A median of 8 (interquartile range, 6-10) of a possible 19 CERT items was reported. The amount of items described of the 13 Toigo and and Boutellier exercise descriptors ranged from 0 to 11.

CONCLUSION

A variety of resistance exercises targeted at the ankle plantar flexors were used as part of early functional rehabilitation after Achilles tendon rupture. However, most studies provided inadequate description of resistance exercise interventions. J Orthop Sports Phys Ther 2020;50(12):681-691. Epub 23 Oct 2020. doi:10.2519/jospt.2020.9463.

Correlation between ankle plantar flexor strength and leg extensor torque

[Purpose] The purpose of this study is to consider the correlation between ankle plantar flexor strength and leg extensor torque in order to investigate whether the leg extension torque can be expected to increase as the triceps surae muscle strength is increased. [Participants and Methods] Healthy adults of 30 males and 22 females were recruited. Hand Held Dynamometer was used to measure ankle plantar flexor strength. Strength Ergo 240 was used to measure leg extensor torque. After measurement, a correlation between these factors was investigated by gender. [Results] For both males and females, a significant positive correlation between the left and right ankle plantar flexor strength and leg extensor torque was observed. [Conclusion] Actively performing muscle strengthening exercises for ankle plantar flexor by physical therapists was found to be meaningful in increasing leg extensor torque.

Morphological and functional outcomes of operatively treated Achilles tendon ruptures

Objectives: Achilles tendon rupture leads to functional impairments and these may be underpinned by morphological changes in the muscle-tendon unit. The functional performance of the injured limb will be impaired regardless of time since surgery and these impairments occur alongside changes in muscle-tendon morphology. Methods: Following operative treatment of Achilles tendon rupture and short-term immobilization, 12 patients completed a battery of tests during a single visit to the laboratory (performed an average of 4.4 ± 2.6 years post-surgery). Patients completed the Achilles' tendon rupture score (ATRS), tests of the ankle and hip range of motion (ROM) and ultrasound measurements of muscle-tendon architecture. Data on isokinetic (30°/s, 60°/s) plantar flexion strength, jumping performance and walking-running were also collected on the same visit. Percentage deficits were expressed relative to the non-injured limb and determined for statistical significance (p < 0.05). Relationships between outcome measures and time since surgery were tested using Pearson's correlation coefficients (p < 0.05). Results: The repaired limb showed a shorter muscle fascicle length (12.1-19.6%), increased fascicle pennation (18.0 ± 22.14%) and reduced muscle thickness (9.1-20.1%) in the gastrocnemius and/or soleus along with greater tendon cross-sectional area (46.7 ± 34.47%). Functionally, the repaired limb displayed lower countermovement jump height (-12.6 ± 15.68%) and longer drop jump contact times (5.5 ± 5.7%). Also, the repaired limb showed reduced hip internal-external ROM (6.3 ± 8.2%) but no differences existed between limbs for plantar flexion ROM and strength or gait characteristics. Good ATRS outcomes were reported (mean: 87.9 ± 16.2, range: 43-100) which related to time since surgery (r = 0.79) but individual ATRS items did not correlate with corresponding objective measures. Conclusion: Plantar flexor atrophy following surgically treated Achilles tendon rupture is partially compensated for by remodeling of the fascicles; however, impairments may still persist many years into the postoperative period although these may be more pronounced in high-velocity activities.

Defining Components of Early Functional Rehabilitation for Acute Achilles Tendon Rupture: A Systematic Review

Background:

Early functional rehabilitation is frequently discussed in treating Achilles tendon rupture. A consistent definition of what constitutes early functional rehabilitation has not been established across the literature, despite studies supporting its efficacy. A standardized definition would be helpful to pool data across studies, allow for between-study comparisons, and ultimately work toward developing clinical guidelines.

Purpose:

To define early functional rehabilitation (including when it is initiated and what it entails) when used to treat Achilles tendon rupture and to identify outcome measures for evaluating the effect of treatment.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

Ovid MEDLINE, EMBASE, PEDro, CINAHL, and Cochrane databases were searched for relevant studies. Eligibility criteria for selecting studies consisted of randomized controlled trials, cohort studies, and case series (≥10 participants) including weightbearing or exercise-based interventions within 8 weeks after Achilles tendon rupture.

Results:

A total of 174 studies published between 1979 and 2018 were included. Studies were rated a median (interquartile range [IQR]) of 17 (15-20) on the Downs & Black checklist and included 9098 participants. Early functional rehabilitation incorporated weightbearing (95%), range of motion (73%), and isometric/strengthening exercises (50%). Weightbearing was initiated within the first week, whereas exercise (eg, ankle range of motion, strengthening, whole-body conditioning) was initiated in the second week. Initiation of exercises varied based on whether treatment was nonsurgical (mean, 3.0 weeks; IQR, 2.0-4.0 weeks) or simple (mean, 2.0 weeks; IQR, 0.0-2.3 weeks) or augmented surgical repair (mean, 0.5 weeks; IQR, 0.0-2.8 weeks) (P = .017). Functional outcomes including ankle range of motion (n = 84) and strength (n = 76) were reported in 130 studies. Other outcome domains included patient-reported outcomes (n = 89), survey-based functional outcomes (n = 50), and tendon properties (n = 53).

Conclusion:

Early functional rehabilitation includes weightbearing and a variety of exercise-based interventions initiated within the first 2 weeks after acute Achilles tendon rupture/repair. Because early functional rehabilitation has lacked a standardized definition, interventions and outcome measures are highly variable, and pooling data across studies should be done with attention paid to what was included in the intervention and how treatment was assessed.

Short-term functional assessment of gait, plantarflexor strength, and tendon properties after Achilles tendon rupture

BACKGROUND

Although early functional rehabilitation (EFR) has been suggested to yield rapid functional recovery after Achilles tendon rupture (ATR) compared to conventional rehabilitation (CR), most quantitative assessments occur long after rehabilitation has been completed. Few data exist regarding the short-term functional gains during the healing period post-ATR. It remains unclear if EFR allows for an objectively faster return to function. The aim of this study was to examine EFR's effect on gait, plantarflexor strength, and tendon properties in early post-operative follow-ups.

METHODS

Fourteen patients received either EFR (n = 6) or CR (n = 8) after percutaneous ATR repair. Functional gait analysis, maximal voluntary isometric contractions (MVICs), and Achilles tendon properties were assessed at 8 and 12 weeks post-op.

RESULTS

Comparison of EFR against CR yielded no statistically significant differences in ankle kinematics or kinetics, Achilles tendon properties or MVICs on the injured (INJ) ankle at either time point. During gait, only CR patients demonstrated significantly lower plantarflexion moments on INJ at 8 weeks (0.817 ± 0.151 N·m/kg vs. 1.172 ± 0.177 N·m/kg, p = 0.002). All patients exhibited deficits in plantarflexor moment at 8 weeks and eversion moment at 12 weeks on INJ during gait that had effect sizes of note when compared to CON.

SIGNIFICANCE

ATR patients, regardless of rehabilitation, exhibit deficits in gait, AT properties, and single-limb strength at 8 weeks. Though AT properties and single-limb plantarflexor isometric strength remain at a deficit at 12 weeks, bipedal plantarflexion moments are comparable between INJ and CON. Though effect size calculations suggested clinically significant differences, clear benefits of EFR compared to CR were not found.

Biomechanical properties of different techniques used in vitro for suturing mid-substance Achilles tendon ruptures

BACKGROUND

The Dresden technique preserves the paratenon during Achilles tendon repair and may improve the plantarflexor mechanism when combined with mobilization during early rehabilitation. However, the surgical repair design for Achilles tendon ruptures can affect rates of re-rupture or lengthening. Therefore, the aim of this study was to determine the biomechanical properties of the Krackow, Double-Kessler, Double-Dresden, and Triple-Dresden techniques used for repairing mid-substance Achilles tendon ruptures during cyclical and maximum traction.

METHODS

Sixty mid-substance bovine tendons repaired after transverse rupturing were divided randomly into four groups by repair technique: Krackow, Double-Kessler, Double-Dresden, and Triple-Dresden. Cyclical tractions of 4.7, 5.8, 7.9, and 11.7mm (equivalent to 5°, 8°, 10°, and 15° of dorsal flexion, respectively) were applied to determine gapping, tensile strength, nominal suture stress, repair deformation, and specimens with clinical failure (gap>5mm). Maximal traction was applied to measure maximum strength and failure type (i.e. suture, knot, or tendon).

FINDINGS

The Triple-Dresden technique resulted in decreased gapping, nominal suture stress, repair deformation, and quantity of specimens with clinical failure as compared to the other techniques. Furthermore, Triple-Dresden tendons showed greater comparative tensile and maximum strength. During maximal traction testing, this technique presented tendon failure, whereas the Krackow, Double-Kessler, and Double-Dresden techniques had suture failures.

INTERPRETATION

Triple-Dresden repair results in better cyclical and maximum traction strengths, suggesting that this technique might be more appropriate when performing early mobilization after mid-substance Achilles tendon rupture repair.