Effects of early progressive eccentric exercise on muscle structure after anterior cruciate ligament reconstruction

Evidence Review for Preventing Osteoarthritis After an Anterior Cruciate Ligament Injury: An Osteoarthritis Action Alliance Consensus Statement

CONTEXT

The Osteoarthritis Action Alliance formed a secondary prevention task group to develop a consensus on secondary prevention recommendations to reduce the risk of osteoarthritis after a knee injury.

OBJECTIVE

Our goal was to provide clinicians with secondary prevention recommendations that are intended to reduce the risk of osteoarthritis after a person has sustained an anterior cruciate ligament injury. Specifically, this manuscript describes our methods, literature reviews, and dissenting opinions to elaborate on the rationale for our recommendations and to identify critical gaps.

DESIGN

Consensus process.

SETTING

Virtual video conference calls and online voting.

PATIENTS OR OTHER PARTICIPANTS

The Secondary Prevention Task Group consisted of 29 members from various clinical backgrounds.

MAIN OUTCOME MEASURE(S)

The group initially convened online in August 2020 to discuss the target population, goals, and key topics. After a second call, the task group divided into 9 subgroups to draft the recommendations and supportive text for crucial content areas. Twenty-one members completed 2 rounds of voting and revising the recommendations and supportive text between February and April 2021. A virtual meeting was held to review the wording of the recommendations and obtain final votes. We defined consensus as >80% of voting members supporting a proposed recommendation.

RESULTS

The group achieved consensus on 15 of 16 recommendations. The recommendations address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models.

CONCLUSIONS

This consensus statement reflects information synthesized from an interdisciplinary group of experts based on the best available evidence from the literature or personal experience. We hope this document raises awareness among clinicians and researchers to take steps to mitigate the risk of osteoarthritis after an anterior cruciate ligament injury.

Aspetar clinical practice guideline on rehabilitation after anterior cruciate ligament reconstruction

This guideline was developed to inform clinical practice on rehabilitation after anterior cruciate ligament reconstruction (ACLR) and was performed in accordance with the Appraisal of Guidelines for REsearch & Evaluation II (AGREE II) instrument and used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. A Guideline Development Group systematically searched and reviewed evidence using randomised clinical trials and systematic reviews to evaluate the effectiveness of rehabilitation interventions and guide clinicians and patients on the content of the optimal rehabilitation protocol after ACLR.The guideline targets patients during rehabilitation after ACLR and investigates the effectiveness of the available interventions to the physiotherapist, alone or in combination (eg, exercise, modalities, objective progression criteria). Exercise interventions should be considered the mainstay of ACLR rehabilitation. However, there is little evidence on the dose-response relationship between volume and/or intensity of exercise and outcomes. Physical therapy modalities can be helpful as an adjunct in the early phase of rehabilitation when pain, swelling and limitations in range of motion are present. Adding modalities in the early phase may allow earlier pain-free commencement of exercise rehabilitation. Return to running and return to training/activity are key milestones for rehabilitation after ACLR. However, there is no evidence on which progression or discharge criteria should be used.While there is a very low level of certainty for most components of rehabilitation, most of the recommendations provided in this guideline were agreed to by expert clinicians. This guideline also highlights several new elements of ACLR management not reported previously.

Effects of eccentric, concentric and eccentric/concentric training on muscle function and mass, functional performance, cardiometabolic health, quality of life and molecular adaptations of skeletal muscle in COPD patients: a multicentre randomised trial

Background

Chronic obstructive pulmonary disease (COPD) is the third cause of death worldwide. COPD is characterised by dyspnoea, limited exercise tolerance, and muscle dysfunction. Muscle dysfunction has been linked to dysregulation between muscle protein synthesis, myogenesis and degradation mechanisms. Conventional concentric cycling has been shown to improve several clinical outcomes and reduce muscle wasting in COPD patients. Eccentric cycling is a less explored exercise modality that allows higher training workloads imposing lower cardio-metabolic demand during exercise, which has shown to induce greater muscle mass and strength gains after training. Interestingly, the combination of eccentric and concentric cycling training has scarcely been explored. The molecular adaptations of skeletal muscle after exercise interventions in COPD have shown equivocal results. The mechanisms of muscle wasting in COPD and whether it can be reversed by exercise training are unclear. Therefore, this study aims two-fold: (1) to compare the effects of 12 weeks of eccentric (ECC), concentric (CONC), and combined eccentric/concentric (ECC/CONC) cycling training on muscle mass and function, cardiometabolic health, physical activity levels and quality of life in severe COPD patients; and (2) to examine the molecular adaptations regulating muscle growth after training, and whether they occur similarly in specific muscle fibres (i.e., I, IIa and IIx).

Methods

Study 1 will compare the effects of 12 weeks of CONC, ECC, versus ECC/CONC training on muscle mass and function, cardiometabolic health, levels of physical activity and quality of life of severe COPD patients using a multicentre randomised trial. Study 2 will investigate the effects of these training modalities on the molecular adaptations regulating muscle protein synthesis, myogenesis and muscle degradation in a subgroup of patients from Study 1. Changes in muscle fibres morphology, protein content, genes, and microRNA expression involved in skeletal muscle growth will be analysed in specific fibre-type pools.

Discussion

We aim to demonstrate that a combination of eccentric and concentric exercise could maximise the improvements in clinical outcomes and may be ideal for COPD patients. We also expect to unravel the molecular mechanisms underpinning muscle mass regulation after training in severe COPD patients.

Trial Registry: Deutshches Register Klinischer Studien; Trial registration: DRKS00027331; Date of registration: 12 January 2022. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00027331.

A Semi-recumbent Eccentric Cycle Ergometer Instrumented to Isolate Lower Limb Muscle Contractions to the Appropriate Phase of the Pedal Cycle

Eccentric (ECC) cycling is used in rehabilitation and sports conditioning settings. We present the construction and mode of operation of a custom-built semi-recumbent ECC cycle designed to limit the production of lower limb muscle activity to the phase of the pedal cycle known to produce ECC contractions. A commercially available semi-recumbent frame and seat (Monarch, 837E Semi-recumbent Bike, Sweden) were used to assemble the ergometer. An electrical drive train system was constructed using individual direct drive servo motors. To avoid active muscle activation occurring during the non-ECC pedaling phase of cycling, a “trip” mechanism was integrated into the drivetrain system using a servo-driven regenerative braking mechanism based on the monitoring of the voltage produced over and above a predetermined threshold produced by the motors. The servo drive internal (DC bus) voltage is recorded and internally monitored during opposing (OPP) and non-opposing (N-OPP) phases of the pedal cycle. To demonstrate that the cycle functions as desired and stops or “trips” when it is supposed to, we present average (of 5 trials) muscle activation patterns of the principal lower limb muscles for regular ECC pedal cycles in comparison with one pedal cycle during which the muscles activated outside the desired phase of the cycle for a sample participant. This semi-recumbent ECC cycle ergometer has the capacity to limit the occurrence of muscle contraction only to the ECC phase of cycling. It can be used to target that mode of muscle contraction more precisely in rehabilitation or training studies.

Use of rating of perceived exertion during anterior cruciate ligament reconstruction and knee osteoarthritis rehabilitation: a scoping review protocol

INTRODUCTION

Anterior cruciate ligament (ACL) tear and knee osteoarthritis (KOA) are the most prevalent musculoskeletal disorders of the knee. Rehabilitation with progressive resistance training is recommended for both disorders. Rating of perceived exertion (RPE) is widely used to prescribe, monitor, and control exercise load. However, the lack of detailed methodological description and variability in the use of RPE may hinder its validity. This scoping review summarises methodological aspects of the use of RPE in resistance exercises during ACL reconstruction and KOA rehabilitation. We also aim to identify possible methodological issues related to the use of RPE and provide recommendations for future studies.

METHODS AND ANALYSIS

This scoping review protocol was developed following the Joanna Briggs Institute and Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement extension for Scoping Reviews. The search will be conducted in Medline/PubMed, Embase, CINAHL, PEDro, Central and SPORTDiscus databases. The terms "anterior cruciate ligament rehabilitation", "knee osteoarthritis" and "resistance exercise" and their synonymous will be used isolated and combined (boolean operators AND/OR/NOT). Two reviewers will independently conduct title and abstract screening and evaluate full texts of potentially eligible articles. Data related to study design, sample, intervention characteristics and RPE outcomes will be extracted, summarised and qualitatively analysed.

ETHICS AND DISSEMINATION

The proposed scoping review does not require ethical approval since it will synthesise information from publicly available studies. Regarding dissemination activities, results will be submitted for publication in a scientific journal and presented at conferences in the field.

Should We Trust Perceived Effort for Loading Control and Resistance Exercise Prescription After ACL Reconstruction?

CONTEXT

The rating of perceived effort (RPE) is a common method used in clinical practice for monitoring, loading control, and resistance training prescription during rehabilitation after rupture and anterior cruciate ligament reconstruction (ACLR). It is suggested that the RPE results from the integration of the afferent feedback and corollary discharge in the motor and somatosensory cortex, and from the activation of brain areas related to emotions, affect, memory, and pain (eg, posterior cingulate cortex, precuneus, and prefrontal cortex). Recent studies have shown that rupture and ACLR induce neural adaptations in the brain commonly associated with the RPE. Therefore, we hypothesize that RPE could be affected because of neural adaptations induced by rupture and ACLR.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

RPE could be directly altered by changes in the activation of motor cortex, posterior cingulate cortex, and prefrontal cortex. These neural adaptations may be induced by indirect mechanisms, such as the afferent feedback deficit, pain, and fear of movement (kinesiophobia) that patients may feel after rupture and ACLR.

CONCLUSION

Using only RPE for monitoring, loading control, and resistance training prescription in patients who had undergone ACLR could lead to under- or overdosing resistance exercise, and therefore, impair the rehabilitation process.

STRENGTH-OF-RECOMMENDATION TAXONOMY

3C.

Interventions to prevent and treat sarcopenia in a surgical population: a systematic review and meta-analysis

BACKGROUND

The aim of this systematic review was to summarize the results of trials evaluating interventions for the reduction of sarcopenia in patients undergoing surgery.

METHODS

Searches were conducted using the Cochrane Central Register of Controlled Trials, MEDLINE and Embase. RCTs evaluating exercise, dietary or pharmacological interventions to address sarcopenia in the perioperative period were included. Treatment effect estimates were expressed as standardized mean differences (MDs) with confidence intervals, and heterogeneity was expressed as I2 values.

RESULTS

Seventy trials including 3402 participants were selected for the data synthesis. Exercise interventions significantly increased muscle mass (MD 0.62, 95 per cent c.i. 0.34 to 0.90; P < 0.001), muscle strength (MD 0.55, 0.39 to 0.71; P < 0.001), measures of gait speed (MD 0.42, 0.05 to 0.79; P = 0.03), and reduced time for completion of set exercises (MD -0.76, -1.12 to -0.40; P < 0.001) compared with controls. Subgroup analysis showed that interventions in the early postoperative period were more likely to have a positive effect on muscle mass (MD 0.71, 0.35 to 1.07; P < 0.001) and timed tests (MD -0.70, -1.10 to -0.30; P = 0.005) than preoperative interventions. Treatment effects on muscle mass (MD 0.09, -0.31 to 0.49; P = 0.66) and strength (MD 0.46, -0.01 to 0.92; P = 0.05) were attenuated by the presence of cancer. Results of analyses restricted to nine trials at low risk of allocation concealment bias and fourteen trials at low risk of attrition bias were comparable to those of the primary analysis. Risk-of-bias assessment showed that most trials were at high risk of incomplete outcome and attrition bias, thus reducing the estimate of certainty of the evidence according to the GRADE assessment tool.

CONCLUSION

Exercise interventions appear beneficial in reducing the impact of sarcopenia. Because of the high risk of bias and low certainty of the current evidence, large RCTs using standardized measures of muscle mass should be undertaken.

Hamstrings Muscle Morphology After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

BACKGROUND

Hamstrings muscle morphology is determinant of muscle function (i.e. strength). Among individuals with ACL reconstruction (ACLR), less cross-sectional area (CSA) and volume in the ACLR-limb are associated with muscle weakness, and may contribute to lower rates of return to preinjury activity level and an increased risk for long-term sequelae.

OBJECTIVES

To effectively treat muscular impairments, an accurate understanding of differences in hamstrings morphology following ACLR is needed. A systematic review and meta-analysis were undertaken to describe the morphology of the hamstring muscle complex after ACLR.

METHODS

We searched five databases for studies evaluating the difference between hamstrings size and architecture in individuals with ACLR. Two independent reviewers assessed each paper for inclusion and quality. Means and standard deviations were extracted from each included study to allow fixed-effect size meta-analysis calculations for comparison of results.

RESULTS

Twenty-four studies were included for final review. Eight categories of morphological outcomes were identified, and studies were grouped accordingly: (1) volume, (2) cross-sectional area (CSA), (3) muscle length, (4) muscle thickness, (5) fascicle length, (6) pennation angle, (7) fiber area, and (8) fiber type. Meta-analysis demonstrated lower hamstrings volume in the ACLR-limb in both contralateral and control group comparisons, and lower CSA, length, and thickness in the ACLR-limb in contralateral comparisons. The semitendinosus and gracilis were most profoundly impacted. Limited moderate evidence demonstrated greater biceps femoris pennation angle in the ACLR-limb.

CONCLUSIONS

Individuals with ACLR demonstrated large deficits in semitendinosus and gracilis muscle CSA and volume in the ACLR-limb compared contralaterally, with no differences observed in the biceps femoris or semimembranosus. Clinical implications regarding assessment and treatment of individuals with ACLR are discussed.

Lower Limb Muscle Size after Anterior Cruciate Ligament Injury: A Systematic Review and Meta-Analysis

BACKGROUND

Anterior cruciate ligament (ACL) injury is known to have a number of deleterious effects on lower limb muscle function. Alterations in muscle size are one such effect that have implications towards reductions in strength and functioning of the lower limbs. However, a comprehensive analysis of alterations in muscle size has yet to be undertaken.

OBJECTIVE

To systematically review the evidence investigating lower limb muscle size in ACL injured limbs.

DESIGN

Systematic review DATA SOURCES: Database searches of Medline, SPORTDiscus, Embase, Cinahl and Web of Science as well as citation tracking and manual reference list searching.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Individuals with ACL deficient or reconstructed limbs with an assessment of lower limb muscle size and control limb data (contralateral or uninjured control group) METHODS: Risk of bias assessment was completed on included studies. Data were extracted and where possible meta-analyses performed. Best evidence synthesis was also undertaken.

RESULTS

49 articles were included in this review, with 37 articles included in the meta-analyses. 66 separate meta-analyses were performed using various measures of lower limb muscle size. Across all measures, ACL deficient limbs showed lesser quadriceps femoris muscle size (d range = - 0.35 to - 0.40), whereas ACL reconstructed limbs showed lesser muscle size in the quadriceps femoris (d range = - 0.41 to - 0.69), vastus medialis (d = - 0.25), vastus lateralis (d = - 0.31), hamstrings (d = - 0.28), semitendinosus (d range = - 1.02 to - 1.14) and gracilis (d range = - 0.78 to - 0.99) when compared to uninjured limbs.

CONCLUSION

This review highlights the effect ACL injury has on lower limb muscle size. Regardless of whether an individual chooses a conservative or surgical approach, the quadriceps of the injured limb appear to have lesser muscle size compared to an uninjured limb. When undertaking reconstructive surgery with a semitendinosus/gracilis tendon graft, the harvested muscle shows lesser muscle size compared to the uninjured limb.

An Assessment of Randomized Controlled Trial Quality in The Journal of Bone & Joint Surgery: Update from 2001 to 2013

BACKGROUND

The quality of reporting of randomized controlled trials (RCTs) published in The Journal of Bone & Joint Surgery (JBJS) from 1988 to 2000 was previously analyzed. The purpose of this current study was to analyze the quality of reporting of RCTs published in JBJS from 2001 to 2013 to identify trends over time and potential areas of improvement for future clinical trials.

METHODS

A manual search of the JBJS database identified RCTs published between January 2001 and December 2013. Quality assessments, using the Detsky quality-of-reporting index (Detsky score), a modified Cochrane risk-of-bias tool, and abstraction of relevant data identifying predictors of quality, were conducted.

RESULTS

A total of 5,780 publications were identified in JBJS from 2001 to 2013, with 285 RCTs (4.9%), representing an increase from the prior 13-year period. The overall mean transformed Detsky score (and standard error) increased significantly (p < 0.001) from 68.1% ± 1.67% to 76.24% ± 0.72%. The percentage of multicenter RCTs decreased from 67% to 31%. The percentage of positive trials also decreased from 80% to 50.5%, as did the mean sample size (212 to 166). Regression analysis indicated that trials with an epidemiologist as the first author and nonsurgical trials were significantly associated (p = 0.001) with a higher overall trial quality score. The categories of the lowest mean methodology scores were randomization and concealment, eligibility criteria, and reasons for patient exclusion, as identified with the Detsky score, and patient and assessor blinding, as identified with the risk-of-bias assessment.

CONCLUSIONS

The quantity and quality of published RCTs in JBJS have increased in the 2001 to 2013 time period compared with the previous time period. Although these improvements are encouraging, trends to smaller, single-center trials were also observed. To efficiently determine the efficacy of orthopaedic treatments and limit bias, high-quality randomized trials of appropriate sample size and rigorous design are needed.

Implementing Eccentric Resistance Training-Part 2: Practical Recommendations

The purpose of this review is to provide strength and conditioning practitioners with recommendations on how best to implement tempo eccentric training (TEMPO), flywheel inertial training (FIT), accentuated eccentric loading (AEL), and plyometric training (PT) into resistance training programs that seek to improve an athlete's hypertrophy, strength, and power output. Based on the existing literature, TEMPO may be best implemented with weaker athletes to benefit positional strength and hypertrophy due to the time under tension. FIT may provide an effective hypertrophy, strength, and power stimulus for untrained and weaker individuals; however, stronger individuals may not receive the same eccentric (ECC) overload stimulus. Although AEL may be implemented throughout the training year to benefit hypertrophy, strength, and power output, this strategy is better suited for stronger individuals. When weaker and stronger individuals are exposed to PT, they are exposed to an ECC overload stimulus as a result of increases in the ECC force and ECC rate of force development. In conclusion, when choosing to utilize ECC training methods, the practitioner must integrate these methods into a holistic training program that is designed to improve the athlete's performance capacity.

Isokinetic eccentric training is more effective than constant load eccentric training for quadriceps rehabilitation following anterior cruciate ligament reconstruction: a randomized controlled trial

OBJECTIVE

To compare the effects of conventional (constant load) eccentric training and isokinetic eccentric training on quadriceps muscle mass, strength and functional performance in recreational athletes following anterior cruciate ligament (ACL) reconstruction.

METHODS

Thirty recreational male athletes (25 years old) undergoing ACL reconstruction received a standard rehabilitation program. Volunteers were randomized to conventional group (CG; n = 15) or isokinetic group (IG; n = 15) to be engaged in a 6-week (2 sessions/week) quadriceps eccentric training program at the extensor chair or at the isokinetic dynamometer, respectively. Assessments of quadriceps muscle mass (through magnetic resonance imaging), strength (through isokinetic dynamometry) and self-aware functionality (through questionnaire) were performed before and after the training programs. Single leg hop test performance was assessed only at post-training evaluation.

RESULTS

IG had significantly higher improvements than CG (p < 0.05) for all muscle mass outcomes (+17-23% vs. +5-9%), as well as for isometric (+34% vs. +20%) and eccentric (+85% vs. +23%) peak torques. There was no between-group difference (p > 0.05) for concentric peak torque, Lysholm score, and single leg hop test.

CONCLUSION

Isokinetic eccentric training promotes greater responses than conventional eccentric training on quadriceps muscle mass and strength of recreational athletes following ACL reconstruction.

Access to Physical Therapy for Pediatric and Adolescent Patients Following Orthopedic Surgery

The objective of this study was to evaluate the relationship between insurance status and access to physical therapy (PT). Masked telephone interviews with PT facilities in a major metropolitan area were conducted with researchers posing as parents of children. Each facility was called twice: once with a private insurer and once with a government insurer. Earliest available appointment, if the facility accepted insurance, and amount of time required to return a call were recorded. Fifty-four PT clinics responded. Clinics that accepted private insurance were significantly greater than the proportion that accepted government insurance (85.2% vs 14.8%, P < .001). There was no significant difference in time between initial call and first offered appointment, in the 2 insurance conditions (private: 8.09 days, government: 8.67 days, P = .33). There were no significant differences in appointment delays between both insurance conditions. Our study found there was a significantly lower rate of children with government-funded insurance that had access to postsurgical rehabilitation.

Muscle hypotrophy, not inhibition, is responsible for quadriceps weakness during rehabilitation after anterior cruciate ligament reconstruction

PURPOSE

Quadriceps weakness is common after anterior cruciate ligament reconstruction (ACLR). Limited neuromuscular activation may have a role in the weakness. The purpose of this study was to use peripheral magnetic stimulation to measure changes in quadriceps inhibition in patients during rehabilitation from ACLR.

METHODS

Ten patients (7M/3F; age 35 ± 8 years; BMI 26.0 ± 4.8 kg/m²) who had ACLR with patellar tendon autograft were recruited. At 3 and 6 months postoperatively, patients' knee extension peak torque was measured during maximum voluntary isometric contraction (MVIC), magnetic stimulation-evoked contraction, and MVIC augmented with superimposed burst magnetic stimulation to the femoral nerve. All tests were done bilaterally at 30° and 65° of knee flexion on a dynamometer. Central activation ratio was calculated by dividing the peak torque before stimulation by peak torque after stimulation.

RESULTS

Patients had marked deficits in MVIC, with improvement from 3 to 6 months that was more apparent at 65° versus 30° (P < 0.05). There was significant deficit in stimulation-evoked torque on the involved side that diminished over time, and this change occurred differently between the two angles (P < 0.05). Central activation ratio was lower on the involved side versus the noninvolved side and this effect was more prominent at 3 versus 6 months: combining the angles, mean central activation ratio on the involved and noninvolved sides, respectively, was 91.4 ± 7.6% and 97.5 ± 5.3% at 3 months, and 93.0 ± 7.8% and 95.8 ± 6.8% at 6 months.

CONCLUSIONS

At 3 and 6 months after ACLR, there were significant deficits in quadriceps strength and activation. Quadriceps activation levels were high (> 90%) for both sides at both time points. The substantial strength deficits at this postoperative period may be largely due to muscle atrophy with limited contribution from central inhibition. Rehabilitation interventions to normalize quadriceps strength should emphasize hypertrophic stimuli as opposed to neuromuscular activation strategies.

LEVEL OF EVIDENCE

II, prospective cohort study.

CORRELATION BETWEEN ECCENTRIC TRAINING AND FUNCTIONAL TESTS IN SUBJECTS WITH RECONSTRUCTED ACL

ABSTRACT Introduction: Eccentric training and jump tests are widely used to recover and measure deficits in knee strength and functionality after anterior cruciate ligament (ACL) reconstruction. Objective: To correlate knee extension and flexion torque generated by eccentric isokinetic training, with functional jump tests in subjects with reconstructed ACL. Method: Sixteen men with unilateral ACL reconstruction were assessed before and after 12 weeks of eccentric isokinetic training of knee flexors and extensors (3×10 MVC, 2x/week) at 30°/s for extension and flexion torque (isometric; concentric and eccentric at 30 and 120°/s) and functional jump tests (single, triple, cross and figure of 8). Inter- and intra-limb pre- and post-training mean peak torque (MPT), distance and jump test times were compared along with the correlations between these variables, considering P<0.05. Results: The affected limb (AL) showed significant gain of extension and flexion torque (P<0.01) in the different test categories and velocities evaluated. In the non-affected limb (NAL), this only occurred in the eccentric category (30 and 120°/s), in the extension (P<0.01) and flexion (P<0.05 and P<0.01) torques, respectively. In the jumps, there was an increase in distance (single and triple; P<0.05) and a decrease in time (crossed and figure of 8; P<0.01), however, MPT x Jump correlations were weak (r<0.3) in the pre and post-training period in both limbs. Conclusion: Despite the gain in knee extension and flexion torque and jumping performance, the expected correlation was not satisfactory, suggesting that knee functionality involves other variables inherent to motor control. Level of Evidence IV; Type of study: Case series.

Basic science and clinical use of eccentric contractions: History and uncertainties

The peculiar attributes of muscles that are stretched when active have been noted for nearly a century. Understandably, the focus of muscle physiology has been primarily on shortening and isometric contractions, as eloquently revealed by A.V. Hill and subsequently by his students. When the sliding filament theory was introduced by A.F. Huxley and H.E. Huxley, it was a relatively simple task to link Hill's mechanical observations to the actions of the cross bridges during these shortening and isometric contractions. In contrast, lengthening or eccentric contractions have remained somewhat enigmatic. Dismissed as necessarily causing muscle damage, eccentric contractions have been much more difficult to fit into the cross-bridge theory. The relatively recent discovery of the giant elastic sarcomeric filament titin has thrust a previously missing element into any discussion of muscle function, in particular during active stretch. Indeed, the unexpected contribution of giant elastic proteins to muscle contractile function is highlighted by recent discoveries that twitchin-actin interactions are responsible for the "catch" property of invertebrate muscle. In this review, we examine several current theories that have been proposed to account for the properties of muscle during eccentric contraction. We ask how well each of these explains existing data and how an elastic filament can be incorporated into the sliding filament model. Finally, we review the increasing body of evidence for the benefits of including eccentric contractions into a program of muscle rehabilitation and strengthening.

The Positive Benefits of Negative Movement Patterns Following Total Knee Arthroplasty

Introduction:

Eccentric (negative) resistance exercise of the legs using specialized machines has been reported to be useful and often superior to standard exercise following total knee arthroplasty (TKA). Movements that utilize body mass and gravity as a mode of eccentric resistance exercise in a more pragmatic rehabilitation paradigm may also be useful in reversing chronic muscle impairments observed years following surgery. This study explores whether an eccentrically biased, body mass resistance exercise induces greater magnitude of sagittal plane extensor angular impulse of the support torque and individual net joint torque contributions during both squatting and lunging movement patterns 6 weeks following TKA.

Methods:

Cross-sectional laboratory-based study design including 10 patients following primary unilateral TKA (6.5 ± 0.8 weeks.). All patients completed 3 trials of the squat and lunge movement pattern under both a concentric and an eccentric condition. Extensor angular impulse of the support torque and net joint torque contributions were calculated by integrating the joint torque versus time curves. A Two-way analysis of covariance was conducted and contracts of clinical interest were computed using Wald posttest. P Values for all pairwise comparisons were adjusted for multiplicity using Bonferroni multiple comparison procedure.

Results:

The eccentric condition, compared to the concentric condition, displayed larger magnitude of extensor angular impulse during both the squat (P < .001) and lunge (P < .001) movement patterns for the support torques. Similarly, the eccentric condition, compared to the concentric condition, displayed larger magnitude of extensor angular impulse of the hip, knee, and ankle (P < .001) during both movement patterns.

Conclusion:

Eccentrically biased, body mass movement exercises can produce higher levels of extensor angular impulse on the surgical limb in patients early after TKA. Patients in this study were able to tolerate the higher extensor angular impulse demands and performed the eccentrically biased conditions (without specialized machines) that could be beneficial in postoperative rehabilitation.

Hip abductor tendinitis after ACL reconstruction with patellar tendon graft in soccer players. A new clinical complication

 Although ACL reconstruction remains a complex procedure with possible complications, affecting mainly the knee function, but no complications affecting the hip function have been already mentioned in the literature. Here in, we discuss the demographics, clinical course and outcomes of a rare complication such as hip abductors tendinitis, developed in soccer amateur athletes after ACL reconstruction with patellar tendon graft.

Moderate Load Eccentric Exercise; A Distinct Novel Training Modality

Over the last 20 years a number of studies have been published using progressive eccentric exercise protocols on motorized ergometers or similar devices that allow for controlled application of eccentric loads. Exercise protocols ramp eccentric loads over an initial 3 weeks period in order to prevent muscle damage and delayed onset muscle soreness. Final training loads reach 400-500 W in rehabilitative settings and over 1200 W in elite athletes. Training is typically carried out three times per week for durations of 20-30 min. This type of training has been characterizes as moderate load eccentric exercise. It has also been denoted RENEW (Resistance Exercise via Negative Eccentric Work by LaStayo et al., 2014). It is distinct from plyometric exercises (i.e., drop jumps) that impose muscle loads of several thousand Watts on muscles and tendons. It is also distinct from eccentric overload training whereby loads in a conventional strength training setting are increased in the eccentric phase of the movement to match concentric loads. Moderate load eccentric exercise (or RENEW) has been shown to be similarly effective as conventional strength training in increasing muscle strength and muscle volume. However, as carried out at higher angular velocities of joint movement, it reduces joint loads. A hallmark of moderate load eccentric exercise is the fact that the energy requirements are typically 4-fold smaller than in concentric exercise of the same load. This makes moderate load eccentric exercise training the tool of choice in medical conditions with limitations in muscle energy supply. The use and effectiveness of moderate load eccentric exercise has been demonstrated mostly in small scale studies for cardiorespiratory conditions, sarcopenia of old age, cancer, diabetes type 2, and neurological conditions. It has also been used effectively in the prevention and rehabilitation of injuries of the locomotor system in particular the rehabilitation after anterior cruciate ligament surgery.

Evidence-based clinical practice update: practice guidelines for anterior cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus

AIM

The Royal Dutch Society for Physical Therapy (KNGF) instructed a multidisciplinary group of Dutch anterior cruciate ligament (ACL) experts to develop an evidence statement for rehabilitation after ACL reconstruction.

DESIGN

Clinical practice guideline underpinned by systematic review and expert consensus.

DATA SOURCES

A multidisciplinary working group and steering group systematically reviewed the literature and wrote the guideline. MEDLINE and the Cochrane Library were searched for meta-analyses, systematic reviews, randomised controlled trials and prospective cohort studies published between January 1990 and June 2015.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Included literature must have addressed 1 of 9 predetermined clinical topics: (1) preoperative predictors for postoperative outcome, (2) effectiveness of physical therapy, (3) open and closed kinetic chain quadriceps exercises, (4) strength and neuromuscular training, (5) electrostimulation and electromyographic feedback, (6) cryotherapy, (7) measurements of functional performance, (8) return to play and (9) risk for reinjury.

SUMMARY

Ninety studies were included as the basis for the evidence statement. Rehabilitation after ACL injury should include a prehabilitation phase and 3 criterion-based postoperative phases: (1) impairment-based, (2) sport-specific training and (3) return to play. A battery of strength and hop tests, quality of movement and psychological tests should be used to guide progression from one rehabilitation stage to the next. Postoperative rehabilitation should continue for 9-12 months. To assess readiness to return to play and the risk for reinjury, a test battery, including strength tests, hop tests and measurement of movement quality, should be used.

Effects of the belt electrode skeletal muscle electrical stimulation system on lower extremity skeletal muscle activity: Evaluation using positron emission tomography

BACKGROUND

Lower-extremity muscle weakness in athletes after lower limb trauma or surgery can hinder their return to sports, and the associated muscle atrophy may lead to deterioration in performance after returning to sports. Recently, belt electrode skeletal muscle electrical stimulation (B-SES) which can contract all the lower limb skeletal muscles simultaneously was developed. However, no study has evaluated skeletal muscle activity with B-SES. Since only superficial muscles as well as a limited number of muscles can be investigated using electromyography, we investigated whether positron emission tomography (PET) can evaluate the activity of all the skeletal muscles in the body simultaneously. The purpose of this study was to evaluate the effectiveness of the B-SES system using PET.

METHODS

Twelve healthy males (mean age, 24.3 years) were divided into two groups. The subjects in the control group remained in a sitting position for 10 min, and [(18)F] fluorodeoxyglucose (FDG) was intravenously injected. In the exercise group, subjects exercised using the B-SES system for 20 min daily for three consecutive days as a pre-test exercise. On the measurement day, they exercised for 10 min, received an injection of FDG, and exercised for another 10 min. PET-computed tomography images were obtained in each group 60 min after the FDG injection. Regions of interest were drawn in each lower-extremity muscle. We compared each skeletal muscle metabolism using the standardized uptake value.

RESULTS

In the exercise group, FDG accumulation in the gluteus maximus, gluteus medius, gluteus minimus, quadriceps femoris, sartorius, and hamstrings was significantly higher than the muscles in the control (P < 0.05).

CONCLUSION

Exercise with B-SES increased the skeletal muscle activity of the gluteal muscles as well as the most lower-extremity muscles simultaneously.

Physiological and Neural Adaptations to Eccentric Exercise: Mechanisms and Considerations for Training

Eccentric exercise is characterized by initial unfavorable effects such as subcellular muscle damage, pain, reduced fiber excitability, and initial muscle weakness. However, stretch combined with overload, as in eccentric contractions, is an effective stimulus for inducing physiological and neural adaptations to training. Eccentric exercise-induced adaptations include muscle hypertrophy, increased cortical activity, and changes in motor unit behavior, all of which contribute to improved muscle function. In this brief review, neuromuscular adaptations to different forms of exercise are reviewed, the positive training effects of eccentric exercise are presented, and the implications for training are considered.

Neuromuscular efficiency of the vastus lateralis and biceps femoris muscles in individuals with anterior cruciate ligament injuries

Objective

To analyze strength and integrated electromyography (IEMG) data in order to determine the neuromuscular efficiency (NME) of the vastus lateralis (VL) and biceps femoris (BF) muscles in patients with anterior cruciate ligament (ACL) injuries, during the preoperative and postoperative periods; and to compare the injured limb at these two times, using the non-operated limb as a control.

Methods

EMG data and BF and VL strength data were collected during three maximum isometric contractions in knee flexion and extension movements. The assessment protocol was applied before the operation and two months after the operation, and the NME of the BF and VL muscles was obtained.

Results

There was no difference in the NME of the VL muscle from before to after the operation. On the other hand, the NME of the BF in the non-operated limb was found to have increased, two months after the surgery.

Conclusions

The NME provides a good estimate of muscle function because it is directly related to muscle strength and capacity for activation. However, the results indicated that two months after the ACL reconstruction procedure, at the time when loading in the open kinetic chain within rehabilitation protocols is usually started, the neuromuscular efficiency of the VL and BF had still not been reestablished.

Deficits in Quadriceps Strength and Patient-Oriented Outcomes at Return to Activity After ACL Reconstruction: A Review of the Current Literature

Context:

Side-to-side quadriceps strength deficits are linked to hazardous lower extremity mechanics and reduced function at a time when individuals are returned to activity after anterior cruciate ligament (ACL) reconstruction. As a result, generalized criteria have emerged in the literature, wherein researchers are recommending that patients be cleared for participation once side-to-side differences in strength are ≤10% of the noninjured limb. Similar recommendations exist for patient-oriented outcomes (ie, self-reported function and hop tests), where deficits of ≤10% are considered ideal at return to activity. It is unclear how many studies actually achieve these clinically recommended results.

Evidence Acquisition:

Articles that reported quadriceps strength deficits as compared to the contralateral limb were collected from peer-reviewed sources available on Medline and Web of Science databases (1990 through August 2014). Search terms included the following: anterior cruciate ligament OR ACL AND muscle weakness, anterior cruciate ligament OR ACL AND strength; return-to-activity AND strength; anterior cruciate ligament OR ACL AND quadriceps.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Average side-to-side strength deficits at 6 months postreconstruction were 23% ± 8% (range, 3%-40%), while the average at 12 months postsurgery was found to be 14% ± 6% (range, 3%-28%). The average deficits in self-reported function at 6 months (mean, 14% ± 5%) and 12 months postsurgery (mean, 13% ± 6%) were also found to be >10%. Performance on hop tests was found to be less than optimal at 6 months postsurgery (mean, 11% ± 7%), but improved at 12 months postsurgery (mean, 1.3% ± 2%).

Conclusion:

This review provides an up-to-date account of the typical deficits in strength and patient-oriented outcomes that exist when formalized physical therapy concludes after ACL reconstruction. Based on the studies included, it seems pertinent that researchers and clinicians continue to investigate interventions capable of improving the recovery of quadriceps strength as well as patient-oriented outcomes as the majority of studies report levels that are well below clinical recommendations.

Combination of eccentric exercise and neuromuscular electrical stimulation to improve quadriceps function post-ACL reconstruction

BACKGROUND

Neuromuscular electrical stimulation (NMES) has been shown to reduce quadriceps activation failure (QAF), and eccentric exercise has been shown to lessen muscle atrophy post-ACL reconstruction. Given that these are two critical components of quadriceps strength, intervention combining these therapies may be effective at reinstituting quadriceps function post-reconstruction. Thus, the aim of this study was to evaluate the effectiveness of a combined NMES and eccentric exercise intervention to improve the recovery of quadriceps activation and strength post-reconstruction.

METHODS

Thirty-six individuals post-injury were placed into four treatment groups (N&E, NMES and eccentrics; E-only, eccentrics only; N-only, NMES-only; and STND, standard of care) and ten healthy controls participated. N&E and N-only received the NMES protocol 2× per week for the first 6 weeks post-reconstruction. N&E and E-only received the eccentric exercise protocol 2× per week beginning 6 weeks post-reconstruction. Quadriceps activation was assessed via the superimposed burst technique and quantified via the central activation ratio. Quadriceps strength was assessed via maximal voluntary isomeric contractions (Nm/kg). Data was gathered on three occasions: pre-operative, 12-weeks-post-surgery and at return-to-play.

RESULTS

No differences in pre-operative measures existed (P>0.05). E-only recovered quadriceps activation better than N-only or STND (P<0.05). N&E and E-only recovered strength better than N-only or the STND (P<0.05) and had strength values that were similar to healthy at return-to-play (P>0.05).

CONCLUSION

Eccentric exercise was capable of restoring levels of quadriceps activation and strength that were similar to those of healthy adults and better than NMES alone.

LEVEL OF EVIDENCE

Level 3, Parallel longitudinal study.

Clinical strategies for addressing muscle weakness following knee injury

Muscle strength is a determinate of physical function and increasing muscle strength is an important clinical goal for patients with knee injury. This article discusses the emerging evidence regarding a novel rehabilitation strategy that uses disinhibitory modalities to increase neuromuscular activation in conjunction with traditional muscle strengthening for the purpose of maximizing strength gains following acute knee injury or surgery and in patients with knee osteoarthritis. The use of disinhibitory modalities and specific types of neuromuscular training for clinically maximizing strength are discussed.

What can the first 2 months tell us about outcomes after anterior cruciate ligament reconstruction?

CONTEXT

Substantial research has been conducted on anterior cruciate ligament reconstruction (ACLR) to evaluate patient outcomes. However, little attention has been given to outcomes during the early phase of recovery and how early deficits affect both short- and long-term outcomes.

OBJECTIVE

To identify relationships between demographic (age, sex, and body mass index [BMI]) and intraoperative (isolated ACLR versus primary ACLR + secondary procedures), and postoperative (range-of-motion [ROM] and peak isometric knee-extension force [PIF]) variables during the first 2 months after ACLR using self-reported outcomes.

DESIGN

Cohort study.

SETTING

Outpatient orthopaedic hospital.

PATIENTS OR OTHER PARTICIPANTS

A total of 63 patients (38 men, 25 women; age = 33.0 ± 12.1 years; BMI = 26.3 ± 6.5 kg/m(2)) who underwent ACLR.

MAIN OUTCOME MEASURE(S)

Demographic, intraoperative, and postoperative variables were collected at 1 and 2 months after ACLR and were compared with International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form scores at 1, 2, and ≥12 months.

RESULTS

Significant relationships were identified between ≥12-month IKDC scores and the 1-month (Pearson correlation, r = 0.283, r(2) = 0.08; P = .025) and 2-month (r = 0.301, r(2) = 0.09; P = .017) IKDC scores. After controlling for other variables, we found that the PIF ratio measures at 1 and 2 months were positively associated with 1- and 2-month IKDC scores (P < .001) and BMI was negatively associated with both 1- and 2-month IKDC scores (P < .05). One-month IKDC scores were related to the 1-month difference in knee-flexion ROM (P = .04).

CONCLUSIONS

The IKDC scores during the first 2 months were positively correlated with patients' perceptions of function on long-term IKDC scores. It also appears that improvements in lower extremity strength and flexion ROM deficits were positively associated with short-term IKDC scores. Higher BMI was negatively associated with patients' perceptions of function on short-term IKDC scores.

Effects of isokinetic eccentric training on knee extensor and flexor torque and on gait of individuals with long term ACL reconstruction: A controlled clinical trial

This study investigated the effects of the isokinetic eccentric training (IET) on the knee extensor and flexor torque and kinematic gait parameters in individuals with ACL reconstruction. Sixteen men with ACL reconstructed (ACLr) whose torque and the gait were evaluated, before and after 12 weeks of IET, was compared to a control group (14 individuals). Student t, MANOVA and ANOVA tests were performed with 5% of significance. The training increased the isometric, concentric at 30 and 120º/s (p < .05) and eccentric at 30º/s (p < .01) extensor torque on the affected limb (AL), and eccentric at 30 and 120º/s (p < .01), on the non-affected limb (NAL). In the flexors, there was an increase on the torque: isometric, concentric at 30º/s and eccentric at 30 and 120º/s (p < .01) in AL and in eccentric at 30 (p < .05) and 120º/s (p< .01) in NAL. With respect to the angular and spatio-temporal variables gait, there was no difference between pre-and post-training in LCAr group. Compared to control group, the cycle time, in two members, was lower in LCAr group, and stride length and cadence were higher in the AL of the LCAr (p < .05). Moreover, the knee flexion-extension angles (minimum and maximum) remained lower in LCAr, pre- and post-training (p < .01). The torque gain associated with eccentric isokinetic training did not affect the kinematic parameters of gait in patients undergoing ACL reconstruction.

Principles of postoperative anterior cruciate ligament rehabilitation

It is known that anterior cruciate ligament (ACL) reconstruction needs to be combined with detailed postoperative rehabilitation in order for patients to return to their pre-injury activity levels, and that the rehabilitation process is as important as the reconstruction surgery. Literature studies focus on how early in the postoperative ACL rehabilitation period rehabilitation modalities can be initiated. Despite the sheer number of studies on this topic, postoperative ACL rehabilitation protocols have not been standardized yet. Could common, “ossified” knowledge or modalities really prove themselves in the literature? Could questions such as “is postoperative brace use really necessary?”, “what are the benefits of early restoration of the range of motion (ROM)?”, “to what extent is neuromuscular electrical stimulation (NMES) effective in the protection from muscular atrophy?”, “how early can proprioception training and open chain exercises begin?”, “should strengthening training start in the immediate postoperative period?” be answered for sure? My aim is to review postoperative brace use, early ROM restoration, NMES, proprioception, open/closed chain exercises and early strengthening, which are common modalities in the very comprehensive theme of postoperative ACL rehabilitation, on the basis of several studies (Level of Evidence 1 and 2) and to present the commonly accepted ways they are presently used. Moreover, I have presented the objectives of postoperative ACL rehabilitation in tables and recent miscellaneous studies in the last chapter of the paper.

Construction of an Isokinetic Eccentric Cycle Ergometer for Research and Training

Eccentric cycling serves a useful exercise modality in clinical, research, and sport training settings. However, several constraints can make it difficult to use commercially available eccentric cycle ergometers. In this technical note, we describe the process by which we built an isokinetic eccentric cycle ergometer using exercise equipment modified with commonly available industrial parts. Specifically, we started with a used recumbent cycle ergometer and removed all the original parts leaving only the frame and seat. A 2.2 kW electric motor was attached to a transmission system that was then joined with the ergometer. The motor was controlled using a variable frequency drive, which allowed for control of a wide range of pedaling rates. The ergometer was also equipped with a power measurement device that quantified work, power, and pedaling rate and provided feedback to the individual performing the exercise. With these parts along with some custom fabrication, we were able to construct an isokinetic eccentric cycle ergometer suitable for research and training. This paper offers a guide for those individuals who plan to use eccentric cycle ergometry as an exercise modality and wish to construct their own ergometer.

Eccentric exercise in rehabilitation: safety, feasibility, and application

This nonexhaustive mini-review reports on the application of eccentric exercise in various rehabilitation populations. The two defining properties of eccentric muscle contractions--a potential for high muscle-force production at an energy cost that is uniquely low--are revisited and formatted as exercise countermeasures to muscle atrophy, weakness, and deficits in physical function. Following a dual-phase implementation, eccentric exercise that induces rehabilitation benefits without muscle damage, thereby making it both safe and feasible in rehabilitation, is described. Clinical considerations, algorithms of exercise progression, and suggested modes of eccentric exercise are presented.

Rehabilitation after anterior cruciate ligament reconstruction: a systematic review

BACKGROUND

Rigorous rehabilitation after anterior cruciate ligament (ACL) reconstruction is necessary for a successful surgical outcome. A large number of clinical trials continue to assess aspects of this rehabilitation process. Prior systematic reviews evaluated fifty-four Level-I and II clinical trials published through 2005.

METHODS

Eighty-five articles from 2006 to 2010 were identified utilizing multiple search engines. Twenty-nine Level-I or II studies met inclusion criteria and were evaluated with use of the CONSORT (Consolidated Standards of Reporting Trials) criteria. Topics included in this review are postoperative bracing, accelerated strengthening, home-based rehabilitation, proprioception and neuromuscular training, and six miscellaneous topics investigated in single trials.

RESULTS

Bracing following ACL reconstruction remains neither necessary nor beneficial and adds to the cost of the procedure. Early return to sports needs further research. Home-based rehabilitation can be successful. Although neuromuscular interventions are not likely to be harmful to patients, they are also not likely to yield large improvements in outcomes or help patients return to sports faster. Thus, they should not be performed to the exclusion of strengthening and range-of-motion exercises. Vibration training may lead to faster and more complete proprioceptive recovery but further evidence is needed.

CONCLUSIONS

Several new modalities for rehabilitation after ACL reconstruction may be helpful but should not be performed to the exclusion of range-of-motion, strengthening, and functional exercises. Accelerated rehabilitation does not appear to be harmful but further investigation of rehabilitation timing is warranted.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

The use of eccentrically biased resistance exercise to mitigate muscle impairments following anterior cruciate ligament reconstruction: a short review

Background:

Novel interventions that can safely and effectively overload muscle early following anterior cruciate ligament reconstruction are needed to minimize atrophy and weakness that often becomes longstanding.

Evidence Acquisition:

Eccentrically induced forces can be safely applied during the early stages of rehabilitation following surgery and serve as a potent stimulus for increasing muscle size and strength.

Results:

Compared to a standard rehabilitation program, adding an early 12-week eccentric resistance-training program 3 weeks after anterior cruciate ligament reconstruction induces improvement in quadriceps and gluteus maximus volume at 15 weeks and at 1 year after surgery. Likewise, those who performed an eccentrically biased rehabilitation program also achieved greater improvements in quadriceps strength and hopping ability measured at 15 weeks and at 1 year after surgery.

Clinical Relevance:

There is potential to safely and feasibly perform eccentric contractions as part of a formal rehabilitation program following anterior cruciate ligament reconstruction.

Functional and muscle morphometric effects of ACL reconstruction. A prospective CT study with 1 year follow-up

Computed tomography (CT) was used to explore if changes in muscle cross-sectional area and quality after anterior cruciate ligament (ACL) injury and reconstruction would be related to knee function. Fourteen females and 23 males (16-54 years) underwent clinical tests, subjective questionnaires, and CT 1 week before and 1 year after ACL surgery with semitendinosus-gracilis (STG) graft and rehabilitation. Postoperatively, knee laxity was decreased and functional knee measures and subjective patient scores improved. The most obvious remaining deficit was the quadriceps atrophy, which was significantly larger if the right leg was injured. Right-leg injury also tended to cause larger compensatory hypertrophy of the combined knee flexor and tibial internal rotator muscles (preoperatively). The quadriceps atrophy was significantly correlated with the scores and functional tests, the latter also being related to the remaining size of the gracilis muscle. Biceps femoris hypertrophy and, in males only, semimembranosus hypertrophy was observed following the ACL reconstruction. The lack of semimembranosus hypertrophy in the women could, via tibial internal rotation torque deficit, contribute to the less favorable functional and subjective outcome recorded for the women. The results indicate that the quadriceps, the combined knee flexor/tibial internal rotator muscles, side of ACL injury, and sex are important to consider in rehabilitation after STG graft.

An Eccentrically Biased Rehabilitation Program Early after TKA Surgery

Rehabilitation services are less-studied aspects of the management following total knee arthroplasty (TKA) despite long-term suboptimal physical functioning and chronic deficits in muscle function. This paper describes the preliminary findings of a six-week (12 session) eccentrically-biased rehabilitation program targeted at deficits in physical function and muscle function, initiated one month following surgery. A quasiexperimental, one group, pretest-posttest study with thirteen individuals (6 female, 7 male; mean age 57 ± 7 years) examined the effectiveness of an eccentrically-biased rehabilitation program. The program resulted in improvements in the primary physical function endpoints (SF-36 physical component summary and the six-minute walk test) with increases of 59% and 47%, respectively. Muscle function endpoints (knee extension strength and power) also increased 107% and 93%, respectively. Eccentrically-biased exercise used as an addition to rehabilitation may help amplify and accelerate physical function following TKA surgery.

Does Vitamin E and C Supplementation Improve the Recovery From Anterior Cruciate Ligament Surgery?

Muscular (quadriceps) weakness is a predominant impairment that follows anterior cruciate ligament injury and surgery. This continued weakness impairs activities of daily living and could predispose patients to adverse conditions later in life, such as knee osteoarthritis. Vitamins E and C have potent antioxidant and anti-inflammatory activity. Herein, the authors summarize the state-of-the science and suggest directions for future research endeavors regarding the therapeutic influence of vitamins E and C, or other antioxidants, on the recovery from anterior cruciate ligament injury and surgery.

Effect of early implementation of electrical muscle stimulation to prevent muscle atrophy and weakness in patients after anterior cruciate ligament reconstruction

OBJECTIVE

Following anterior cruciate ligament (ACL) reconstruction, restricted weight bearing and immobilization results in thigh and calf muscle atrophy and weakness. The purpose of this study was to assess the effect of electrical muscle stimulation (EMS) on prevention of muscle atrophy in patients during the early rehabilitation stage after ACL reconstruction.

METHODS

Twenty patients with acute ACL tears were divided into two groups randomly. The control group (CON group) participated in only the usual rehabilitation program. In addition to this protocol, the electrical muscle stimulation group (EMS group) received EMS training using the wave form of 20 Hz exponential pulse from the 2nd post-operative day to 4 weeks after the surgery.

RESULTS

Muscle thickness of vastus lateralis and calf increased significantly 4 weeks after surgery in the EMS group, while it decreased significantly in the CON group. The decline of knee extension strength was significantly less in the EMS group than in the CON group at 4 weeks after the surgery, and the EMS group showed greater recovery of knee extension strength at 3 months after surgery.

CONCLUSIONS

EMS implemented during the early rehabilitation stage is effective in maintaining and increasing muscle thickness and strength in the operated limb.

Periodization: current review and suggested implementation for athletic rehabilitation

BACKGROUND

Clinicians are constantly faced with the challenge of designing training programs for injured and noninjured athletes that maximize healing and optimize performance. Periodization is a concept of systematic progression-that is, resistance training programs that follow predictable patterns of change in training variables. The strength training literature is abundant with studies comparing periodization schemes on uninjured, trained, and untrained athletes. The rehabilitation literature, however, is scarce with information about how to optimally design resistance training programs based on periodization principles for injured athletes. The purpose of this review is to discuss relevant training variables and methods of periodization, as well as periodization program outcomes. A secondary purpose is to provide an anecdotal framework regarding implementation of periodization principles into rehabilitation programs.

EVIDENCE ACQUISITION

A Medline search from 1979 to 2009 was implemented with the keywords periodization, strength training, rehabilitation, endurance, power, hypertrophy, and resistance training with the Boolean term AND in all possible combinations in the English language. Each author also undertook independent hand searching of article references used in this review.

RESULTS

Based on the studies researched, periodized strength training regimens demonstrate improved outcomes as compared to nonperiodized programs.

CONCLUSIONS

Despite the evidence in the strength training literature supporting periodization programs, there is a considerable lack of data in the rehabilitation literature about program design and successful implementation of periodization into rehabilitation programs.

Update on rehabilitation following ACL reconstruction

As anterior cruciate ligament (ACL) reconstruction has evolved to less invasive, more anatomical approaches, rehabilitation of the injured athlete has likewise become more progressive and innovative, with a sound understanding of graft and fixation strength and biologic healing-remodeling constraints. This review discusses these innovations including specific considerations before surgery, when planning rehabilitation timetables, and the importance of reestablishing nonimpaired active and passive knee range of motion and biarticular musculotendinous extensibility in positions of function. Concepts of self-efficacy or confidence and reestablishing the “athlete role” are also addressed. Since ACL injury and reinjury are largely related to the influence of structure-form-function on dynamic knee joint stability, the interrelationships between sensorimotor, neuromuscular, and conventional resistance training are also discussed. Although pivot shift “giving way” relates to function loss following ACL injury, anterior translational laxity often does not. Although there is growing evidence that progressive eccentric training may benefit the patient following ACL reconstruction, there is less evidence supporting the use of functional ACL knee braces. Of considerable importance is selecting and achieving a criteria-based progression to sports-specific training, reestablishing osseous homeostasis and improved bone density, blending open and closed kinetic chain exercises at the appropriate time period, and appreciating the influence of the trunk, upper extremities, and sports equipment use on knee loads. We believe that knee dysfunction and functional recovery should be considered from a local, regional, and global perspective. These concepts are consolidated into our approach to prepare patients for return to play including field testing and maintenance training.

Osseous deficits after anterior cruciate ligament injury and reconstruction: a systematic literature review with suggestions to improve osseous homeostasis

PURPOSE

This systematic review was performed to improve our understanding of the current evidence regarding the influence of anterior cruciate ligament (ACL) injury and reconstruction on involved lower extremity apparent bone mineral density, bone content, or bone area mass (bone integrity).

METHODS

Two independent reviewers performed a Medline search from 1966 to January 2010 using the terms "anterior cruciate ligament" or "ACL" combined with "wound" or "injury" and "bone density" or "osteoporosis." Study inclusion criteria were English-language human studies. Reference sections of selected studies were also reviewed.

RESULTS

Ten studies were identified that met our inclusion criteria. Eight studies performed ACL reconstruction with bone-patellar tendon-bone autografts and interference screw fixation. One study performed ACL reconstruction by use of Achilles tendon allografts with interference screw and staple fixation. Two ACL injury studies either did not involve ACL reconstruction or attempted primary repair with sutures. All studies reported varying levels of decreased bone mineral density, bone content, or bone area mass (bone integrity) at the involved lower extremity after ACL injury that did not return to premorbid levels even with ACL reconstruction and rehabilitation. Sites of reduced bone integrity included the proximal and distal femur, proximal tibia, patella, and calcaneus. Bone loss was increased with limited weight bearing and prolonged disuse or immobilization; however, significant improvements were not observed with accelerated rehabilitation. Some studies reported relations between Lysholm, Tegner, International Knee Documentation Committee survey, or function scores and bone integrity, whereas others reported no or poor relations.

CONCLUSIONS

Involved lower extremity bone integrity is decreased after ACL injury. Current evidence suggests that premorbid bone integrity is not re-established after ACL reconstruction even when accelerated rehabilitation is performed. Recommendations to improve osseous homeostasis and bone health after ACL injury and reconstruction are provided.