Thigh muscle size and strength after anterior cruciate ligament reconstruction and rehabilitation

Beyond weakness: Exploring intramuscular fat and quadriceps atrophy in ACLR recovery

Muscle weakness following anterior cruciate ligament reconstruction (ACLR) increases the risk of posttraumatic osteoarthritis (OA). However, focusing solely on muscle weakness overlooks other aspects like muscle composition, which could hinder strength recovery. Intramuscular fat is a non-contractile element linked to joint degeneration in idiopathic OA, but its role post-ACLR has not been thoroughly investigated. To bridge this gap, we aimed to characterize quadriceps volume and intramuscular fat in participants with ACLR (male/female = 15/9, age = 22.8 ± 3.6 years, body mass index [BMI] = 23.2 ± 1.9, time since surgery = 3.3 ± 0.9 years) and in controls (male/female = 14/10, age = 22.0 ± 3.1 years, BMI = 23.3 ± 2.6) while also exploring the associations between intramuscular fat and muscle volume with isometric strength. Linear mixed effects models assessed (I) muscle volume, (II) intramuscular fat, and (III) strength between limbs (ACLR vs. contralateral vs. control). Regression analyses were run to determine if intramuscular fat or volume were associated with quadriceps strength. The ACLR limb was 8%-11% smaller than the contralateral limb (p < 0.05). No between-limb differences in intramuscular fat were observed (p = 0.091-0.997). Muscle volume but not intramuscular fat was associated with strength in the ACLR and control limbs (p < 0.001-0.002). We demonstrate that intramuscular fat does not appear to be an additional source of quadriceps dysfunction following ACLR and that muscle size only explains some of the variance in muscle strength.

The optimal window for reconstruction of the anterior cruciate ligament (ACL) with respect to quadriceps atrophies lies within 21 to 100 days

PURPOSE

The study's objective was to determine the optimal window for anterior cruciate ligament (ACL) reconstruction with respect to quadriceps atrophies and clinical outcome.

METHODS

For this retrospective, comparative study, 115 patients aged under 35 were included, who received an ACL reconstruction between 2011 and 2016. They were divided into four groups, depending on the time to surgery, to determine the optimal window for reconstruction: (group 1: ≤21 d, group 2: <21d-56d≥, group 3: >56d-100d≥, group 4: >100d). Follow-up was performed one month postoperatively, after a mean of 4.9 (±5.3) months, and after a mean of 3.5 (±1.4) years. Primary endpoints included quadriceps muscle status, range of motion (ROM), pain, swelling, the International Knee Documentation Committee Subjective Knee Form (IKDC), the Lysholm-Score, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the Tegner-Activity-Scale (TAS).

RESULTS

Significantly more quadriceps atrophies were observed in group 1 and group 4, representing reconstructions earlier than 21 and later than 100 days (29% and 41% vs. 9%; p = 0.032). The measurements of knee extension (p = 0.082) and ROM (p = 0.123) were comparable in all groups. Group 1 showed the least pain (0% vs. 15%; p = 0.285) and swelling (0% vs. 23%; p = 0.077) compared to all other groups one month postoperatively. A comparison of postoperative clinical scores revealed no significant differences, with group 1 exhibiting the lowest TAS levels.

CONCLUSION

In patients who underwent ACL reconstruction within three weeks or after more than 100 days, a significantly higher incidence of quadriceps atrophy was observed, possibly attributable to the initial inflammatory phase or the delayed reconstruction affecting quadriceps function. However, this impairment may not be observable in elite athletes who undergo reconstruction within hours of the injury.

Clinical Utility of Ultrasound Imaging for Measuring Anterior Thigh Thickness after Anterior Cruciate Ligament Injury in an Individual Patient to Assess Postsurgery Outcome

The present study investigated the clinical utility of ultrasound imaging (USI) for assessing changes in an individual's quadriceps muscle and subcutaneous fat (SF) thickness of the anterior thigh and their relative proportions. A patient was studied prior to and after anterior cruciate ligament reconstruction (ACLR) surgery and during rehabilitation. This case study involved an 18-year-old female recreational athlete with a complete tear of the anterior cruciate ligament (ACL). Tissue thickness (SF and quadriceps muscle) was measured from transverse USI of the anterior thigh before surgery, at weekly intervals during 12 weeks of postsurgery, and then every 2 weeks for the following 12 weeks (total of 21 measurement sets). Statistically significant differences presurgery to postrehabilitation were found for muscle thickness (p = 0.04) and SF tissue thickness (p = 0.04) measurements. There was no difference in muscle to fat ratio (p = 0.08). Changes in measurements greater than the reported minimal detectable change (MDC) demonstrate the sensitivity of the USI technique as an objective tool to assess clinically useful changes in an individual's anterior thigh muscle thickness post-ACLR surgery and during rehabilitation.

Clinic and Home-Based Exercise with Blood Flow Restriction Resolves Thigh Muscle Atrophy after Anterior Cruciate Ligament Reconstruction with the Bone-Patellar Tendon-Bone Autograft: A Case Report

Anterior cruciate ligament reconstruction (ACLR) results in thigh muscle atrophy. Of the various interventions proposed to mitigate thigh muscle atrophy, exercise with blood flow restriction (BFR) appears safe and effective. Some literature suggests daily exposure to exercise with BFR may be indicated during the early phase of ACLR rehabilitation; this case report outlines the methodology utilized to prescribe clinic- and home-based BFR within an outpatient rehabilitation program. A 15-year-old male soccer player suffered a left knee injury involving the anterior cruciate ligament and both menisci. He underwent ACLR and completed exercise with BFR as part of his clinic- and home-based rehabilitation program, which included practical blood flow restriction during home-based rehabilitation. After 16 weeks of rehabilitation, surgical limb thigh girth values were objectively larger than the non-surgical limb (surgical, 52.25 cm; non-surgical 50 cm), as well as the multi-frequency bioelectrical impedance analysis of his lower-extremity lean body mass (surgical limb, 10.37 kg; non-surgical limb, 10.02 kg). The findings of this case report suggest that the inclusion of clinic- and home-based BFR within an outpatient rehabilitation program may be indicated to resolve thigh muscle atrophy early after ACLR.

The temporal and spatial effects of reconstructive surgery on the atrophy of hindlimb muscles in anterior cruciate ligament transected rats

After anterior cruciate ligament (ACL) injury, a decrease in muscle strength associated with muscle atrophy is frequently observed. The temporal and spatial effects of reconstructive surgery on muscle atrophy have not been examined in detail. This study aimed to 1) reveal the short and mid-term effects of reconstructive surgery on muscle atrophy, and 2) investigate the differences in the degree of atrophy after ACL reconstruction in the hindlimb muscles. ACL transection with or without reconstructive surgery was performed unilaterally on the knees of rats. Untreated rats were used as controls. At one or four weeks post-surgery, the relative muscle wet weights (wet weight/body weight) of the hindlimb muscles were calculated to assess atrophy. At one week post-surgery, muscle atrophy was induced by ACL transection and further aggravated by reconstructive surgery. Reconstructive surgery facilitated recovery from muscle atrophy in some muscles compared with those without reconstructive surgery (ACL transection alone) at four weeks post-surgery. Muscle atrophy after ACL reconstruction was greater in the rectus femoris and plantar flexors than in the semitendinosus and plantar extensors at one week post-surgery. These results indicate that reconstructive surgery exacerbates muscle atrophy in the first week post-surgery, while facilitating recovery between the first and fourth week post-surgery. After reconstructive surgery, muscle atrophy was observed not only in the quadriceps and hamstrings, but also in the lower leg muscles, suggesting the need for muscle strengthening interventions for the lower leg muscles as well as the quadriceps and hamstrings.

Tourniquet Use Improves Intraoperative Parameters, Leading to Similar Postoperative Outcomes Compared With No Tourniquet Use in Anterior Cruciate Ligament Reconstruction: A Prospective, Double-Blind, Randomized Clinical Trial

PURPOSE

To examine the effect of tourniquet use in arthroscopic anterior cruciate ligament reconstruction in terms of: (1) intraoperative visualization with operative time and consumption of sterile saline, and (2) intra- and postoperative blood loss, postoperative pain, opioid consumption, swelling, serum creatine phosphokinase (CPK) and hemoglobin (Hb) concentrations, clinical outcomes, and graft healing.

METHODS

In this prospective randomized clinical trial, patients were assigned to tourniquet inflation (tourniquet-up) or tourniquet deflation (tourniquet-down) groups. Primary outcomes were intraoperative visualization with operative time and sterile saline consumption. Secondary outcomes were intra- and postoperative blood loss, postoperative pain, opioid consumption, swelling, serum CPK, Hb concentration, subjective and objective functional scores, and graft healing.

RESULTS

Intraoperative visualization was satisfactory in 100 of 100 cases in the tourniquet-up group and 64 of 100 cases in the tourniquet-down group (P < .05). The mean operative time was 58.4 ± 5.7 minutes in the tourniquet-up group and 72.5 ± 8.6 minutes in the tourniquet-down group (P < .05). The mean sterile saline consumption was 6.4 ± 2.5 L in the tourniquet-up group and 8.7 ± 4.6 L in the tourniquet-down group (P < .05). The respective amounts of estimated intraoperative and postoperative blood loss were 95.3 ± 25.1 mL and 240.3 ± 44.5 mL in the tourniquet-up group and 230.2 ± 22.3 mL and 75.6 ± 15.3 mL in the tourniquet-down group (P < .05). Our results showed no significant difference in postoperative pain, opioid consumption, percentage of patients using opioids, swelling, mean serum CPK and Hb levels, subjective and objective functional scores, or graft healing (P > .05) between the 2 groups.

CONCLUSIONS

Tourniquet use during anterior cruciate ligament reconstruction significantly improves intraoperative visualization, shortens operative time, and decreases intraoperative sterile saline consumption and blood loss without serious adverse events or greater complication rates based on early postoperative outcomes.

LEVEL OF EVIDENCE

Level I, randomized controlled trial.

Effects of low-intensity resistance exercise with blood flow restriction after high tibial osteotomy in middle-aged women

BACKGROUND

High tibial osteotomy (HTO) is an effective surgical method for treating medial compartment osteoarthritis. However, in most cases after surgery, muscle strength is decreased, and rapid muscle atrophy is observed. Therefore, the purpose of this study is to verify the effects of low-intensity resistance exercise (LIE) with blood flow restriction (BFR) on the cross-sectional area (CSA) of thigh muscles, knee extensor strength, pain, and knee joint function and investigate proper arterial occlusion pressure (AOP) in middle-aged women who underwent HTO.

METHOD

This study was designed as a prospective randomized controlled trial. Forty-two middle-aged women who underwent HTO were randomly divided into three groups and participated in LIE with (40% or 80% AOP applied) or without BFR. The main outcome was the measurement of the CSA of thigh muscles (at 30% and 50% distal length of the femur) before and 12 weeks after treatment. Additionally, knee extension muscle strength, pain, and joint function were evaluated before and 6 and 12 weeks after treatment.

RESULTS

CSA of thigh muscles at 30% and 50% distal length of the femur decreased in the AOP 40% and control groups and was the largest in the AOP 80% group 12 weeks after treatment. Knee extension strength increased in all groups and was the highest in the AOP 80% group 6 and 12 weeks after treatment. Pain improved in all groups, with no intergroup differences. Knee joint function improved in all groups and was superior in the 80% AOP group 12 weeks after treatment.

CONCLUSION

LIE with BFR at 80% AOP was effective in preventing atrophy of the thigh muscle, increasing muscle strength, and improving function. BFR at 40% AOP had no difference in the results when compared with the group in which BFR was not applied. Therefore, LIE with an AOP of 80% is recommended for patients undergoing HTO.

Personalized volumetric assessment of lower body muscles in patients with knee injuries: A descriptive case series

BACKGROUND

Patients with knee joint pathology present with variable muscular responses across the muscles of the lower limb and pelvis. Conventional approaches to characterizing muscle function are limited to gross strength assessments that may overlook subtle changes both in the thigh, hip and shank musculature.

PURPOSE

To describe individualized patterns of lower extremity muscle volumes in patients with knee pathologies.

METHODS

This was a retrospective case series performed in a University medical center. Nine patients diagnosed with meniscus tear recommended to undergo meniscectomy volunteered. Participants underwent 3.0 Tesla magnetic resonance imaging (MRI) of the lower extremities. Thirty-five MRI-derived muscle volumes were compared between limbs and expressed as percentage asymmetry. For additional context, z-scores were also calculated for mass- and height-normalized muscles and pre-determined muscle groupings relative to a normative database.

RESULTS

There were no consistent patterns observed when considering between-limb asymmetries among all patients. The ankle musculature (dorsiflexors, plantar flexors, and invertors) was the only muscle group to be consistently smaller than normal for all patients, with the psoas major and flexor hallucis longus being the only individual muscles. The severity or chronicity of injury and presence of surgical intervention did not appear to have a clear effect on muscle volumes.

CONCLUSION

Patients with a history of meniscal pathology demonstrate inconsistent patterns of lower extremity muscle volumes about the hip, knee, and ankle between limbs and in comparison to uninjured individuals. These data support the need for individualized assessment and intervention in this population.

Anabolic Androgenic Steroids in Orthopaedic Surgery: Current Concepts and Clinical Applications

Despite the well-documented effects of testosterone and its synthetic derivatives—collectively termed anabolic androgenic steroids (AASs)—on the musculoskeletal system, the therapeutic use of these agents has received limited investigation within the field of orthopaedic surgery. In the last 2 decades, preclinical and clinical research has started to identify promising applications of the short-term use of AASs in the perioperative period. There is evidence to suggest that AASs may improve postoperative recovery after anterior cruciate ligament reconstruction and total joint arthroplasty. In addition, AASs may augment the biological healing environment in specific clinical scenarios including muscle injury, fracture repair, and rotator cuff repair. Current literature fails to present strong evidence for or against the use of AASs in orthopaedics, but there is continuous research on this topic. The purpose of this study was to provide a comprehensive overview of the current status of AAS applications in orthopaedic surgery, with an emphasis on preclinical data, clinical studies, and future directions.

Ultrasound Measurement of the Transverse Abdominis, Internal Oblique, and External Oblique Muscles Associated with Forward Head Posture and Reduced Cranio-Vertebral Angle

Background

Abnormal posture can affect the alignment of the cervical spine, which can lead to various physical problems. There are many ways to solve the problem by limiting the area around the neck to restore abnormal neck condition. However, there is a need to look at these problems from an enlarged perspective through the relationship between the cervical spine and trunk. This study aimed to investigate the significance of the thickness of the transverse abdominis, internal oblique, and external oblique muscles in patients with forward head posture and reduced cranio-vertebral angle.

Material/Methods

We included 24 healthy adult males in their 20s without lower back pain. The cranio-vertebral angle (CVA) in all the subjects was measured with the help of pictures taken in the sagittal plane using a digital camera. The thickness of muscles, including transverse abdominis (TrA), internal oblique (IO), and external oblique (EO), was measured using a diagnostic ultrasound device. Pearson’s correlation analysis was used to identify the correlation between the variables measured.

Results

CVA showed a statistically significant correlation with TrA thickness (r=0.506/p=0.012), and among the abdominal muscles, there was a significant correlation between IO and EO thickness (r=0.663/p=0.000).

Conclusions

A reduced CVA due to FHP was significantly associated with reduced TrA thickness. Therefore, increasing the bulk of the abdominal muscles with restoration of the abnormal CVA is a potential treatment approach and requires further study.

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.

A SYSTEMATIC REVIEW OF THE EFFECTS OF BLOOD FLOW RESTRICTION TRAINING ON QUADRICEPS MUSCLE ATROPHY AND CIRCUMFERENCE POST ACL RECONSTRUCTION

Background

ACL reconstruction often results in an extended period of muscle atrophy and weakness. Blood flow restriction (BFR) training is a technique that has been shown to decrease muscle atrophy in a variety of populations.

Purpose

The purpose of this systematic review was to analyze the research presented on the effect of blood flow restriction training on quadriceps muscle atrophy and circumference post ACL reconstruction.

Study Design

Systematic Review.

Methods

Articles were reviewed using the databases Google Scholar, PubMed, and EBSCO. Keywords included blood flow restriction training, ACL reconstruction, and quadriceps.

Inclusion criteria included

English language, peer-reviewed journals; randomized control trials; and articles including blood flow restriction and measurement of quadriceps atrophy and circumference post ACL reconstruction. Exclusion criteria included non-English language publications; studies without a control group; and articles without sufficient data to evaluate the methodology. Four studies met the selection criteria and were assessed using the GRADE scale, which analyzes the strength of a study based on study limitations, precision, consistency, directness, and publication bias. After a GRADE designation was assigned, the following information was extracted from and compared across the studies: participant demographics, cuff used, graft used during ACL reconstruction, tool used to assess muscle atrophy, protocol used, and conclusions.

Results

Three out of four studies showed some amount of an increase in femoral muscle cross sectional area after the use of BFR combined with low-intensity resistance training (LIRT). The strength of all four studies was moderate when assessed using the GRADE scale.

Conclusion

This review of the available evidence yields promising results regarding the use of BFR and LIRT in the remediation of femoral muscle atrophy after an ACL reconstruction. Further research is necessary before BFR can be recommended for use in clinical settings.

Level of evidence

3a.

Ultrasound measurements of superficial and deep masticatory muscles in various postures: reliability and influencers

Masticatory muscle thickness provides objective measurements of the oral motor function, which may change in patients with oral myofascial pain. In this study, we aimed to establish a reliable ultrasound (US) protocol for imaging the superficial and deep masticatory muscles and to identify the potential influencers of the measurements. Forty-eight healthy participants without orofacial pain were enrolled. The intra-and inter-rater reliabilities of US measurements for masseter, temporalis, and lateral pterygoid muscles were assessed. Intraclass correlation coefficients for all muscles were greater than 0.6. The generalised estimating equation was used to analyse the impact of age, gender, laterality, and body mass index on the measurements, whereby age and body mass index were likely to be associated with an increase in masticatory muscle thickness. The thickness tended to be lesser in females. Laterality seemed to exert minimal influence on masticatory muscle thickness. Our study shows acceptable reliability of US in the evaluation of superficial and deep masticatory muscle thickness. Future studies are warranted to validate the usefulness of US imaging in patients with oral myofascial pain syndrome.

Muscle Atrophy After ACL Injury: Implications for Clinical Practice

CONTEXT

Distinct from the muscle atrophy that develops from inactivity or disuse, atrophy that occurs after traumatic joint injury continues despite the patient being actively engaged in exercise. Recognizing the multitude of factors and cascade of events that are present and negatively influence the regulation of muscle mass after traumatic joint injury will likely enable clinicians to design more effective treatment strategies. To provide sports medicine practitioners with the best strategies to optimize muscle mass, the purpose of this clinical review is to discuss the predominant mechanisms that control muscle atrophy for disuse and posttraumatic scenarios, and to highlight how they differ.

EVIDENCE ACQUISITION

Articles that reported on disuse atrophy and muscle atrophy after traumatic joint injury were collected from peer-reviewed sources available on PubMed (2000 through December 2019). Search terms included the following: disuse muscle atrophy OR disuse muscle mass OR anterior cruciate ligament OR ACL AND mechanism OR muscle loss OR atrophy OR neurological disruption OR rehabilitation OR exercise.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

We highlight that (1) muscle atrophy after traumatic joint injury is due to a broad range of atrophy-inducing factors that are resistant to standard resistance exercises and need to be effectively targeted with treatments and (2) neurological disruptions after traumatic joint injury uncouple the nervous system from muscle tissue, contributing to a more complex manifestation of muscle loss as well as degraded tissue quality.

CONCLUSION

Atrophy occurring after traumatic joint injury is distinctly different from the muscle atrophy that develops from disuse and is likely due to the broad range of atrophy-inducing factors that are present after injury. Clinicians must challenge the standard prescriptive approach to combating muscle atrophy from simply prescribing physical activity to targeting the neurophysiological origins of muscle atrophy after traumatic joint injury.

Monitoring changes in knee surface morphology after anterior cruciate ligament reconstruction surgery using 3Dsurface scanning

STUDY DESIGN

Prospective case series.

BACKGROUND

After surgical reconstruction of the anterior cruciate ligament, recovery to pre-injury levels of knee function is challenging. Postoperative edema and muscle atrophy are common roadblocks to full function and are evident in changes to the surface morphology of the knee. There are currently few accessible objective tools to accurately track these morphological changes.

OBJECTIVES

We aimed to determine if 3D surface scanning can be used to monitor changes in the external shape of the knee after surgery and throughout the rehabilitation process.

METHODS

Thirty participants had 3D surface scans taken of their knee, along with questionnaire-based functional outcomes prior to surgery (baseline), and at two-week, six-week, 12-week, and 26-week timepoints post-surgery. Volumetric changes relative to pre-op were assessed using generalized linear growth models for key anatomical regions and correlated with functional outcomes.

RESULTS

Significant swelling of the patella region compared to baseline was evident immediately after surgery (14%, p < 0.001), before returning to pre-operative levels. Changes in volume at this region were significantly associated with patient-reported functional outcomes. Reductions in volume of the regions corresponding to the vastus medialis and lateralis muscles were significant at 12 weeks post-surgery (p = 0.018 and 0.01 respectively) but returned to baseline levels at six months.

CONCLUSION

We demonstrate the use of 3D surface scanning as a method for capturing detailed measurements of knee surface morphology after surgery. Significant changes in external morphology are evident during the rehabilitation process.

Quadriceps Neuromuscular Impairments after Arthroscopic Knee Surgery: Comparison between Procedures

Quadriceps neuromuscular function remains impaired in the short- and long-term following knee arthroscopy for meniscal surgery and/or anterior cruciate ligament (ACL) reconstruction. The aim of this study was to compare quadriceps neuromuscular impairments in patients following meniscal surgery with and without ACL reconstruction. Thirty patients were tested six months after meniscal surgery with (n = 15) and without (n = 15) ACL reconstruction. We bilaterally assessed knee extension maximal voluntary contraction (MVC) torque using dynamometry, vastus lateralis thickness using ultrasound, quadriceps voluntary activation and evoked knee extension torque with transcutaneous electrical stimulation. Patient-reported outcomes were evaluated with the Knee Injury and Osteoarthritis Outcome Score (KOOS). Compared with meniscus patients, ACL patients demonstrated larger asymmetries in MVC torque (15% vs. 5%, p = 0.049) and vastus lateralis thickness (6% vs. 0%, p = 0.021). In ACL patients, asymmetries in MVC torque correlated with asymmetries in evoked torque (r = 0.622, p = 0.013). In meniscus patients, asymmetries in muscle activation correlated with KOOS quality of life (r = 0.619, p = 0.018). Patients demonstrated persistent quadriceps muscle weakness six months after ACL reconstruction, but not after isolated meniscal surgery. Quantitative and/or qualitative muscular changes likely underlie quadriceps muscle weakness in ACL patients, whereas activation failure is associated with poor quality of life in some meniscus patients.

Quadriceps Recovery After Anterior Cruciate Ligament Reconstruction With Quadriceps Tendon Versus Patellar Tendon Autografts

Background

Quadriceps tendon (QT) autografts are being increasingly used for anterior cruciate ligament reconstruction (ACLR). A paucity of studies exist that compare QT autografts with alternative graft options. Additionally, concerns exist regarding quadriceps recovery after graft harvest insult to the quadriceps muscle-tendon unit.

Purpose/Hypothesis

The purpose of this study was to compare quadriceps recovery and functional outcomes in patients with QT versus bone-patellar tendon-bone (BPTB) autografts. The hypothesis was that those with QT autografts would demonstrate superior outcomes.

Study Design

Cohort study; Level of evidence, 3.

Methods

Active patients with a history of primary, unilateral ACLR with soft tissue QT or BPTB autografts participated. Quadriceps recovery was quantified using variables of strength, muscle size, and activation. Knee extensor isometric and isokinetic strength was measured bilaterally with an isokinetic dynamometer and normalized to body weight. Quadriceps activation was measured with the superimposed burst technique. The maximal cross-sectional area of each quadriceps muscle was measured bilaterally using magnetic resonance imaging. Assessors of muscle size were blinded to the graft type and side of ACLR. Functional tests included hop tests and step length symmetry during walking, measured via spatiotemporal gait analysis. Self-reported function was determined with the International Knee Documentation Committee (IKDC) questionnaire. Neuromuscular and functional outcomes were expressed as limb symmetry indices (LSIs: [surgical limb/nonsurgical limb]*100%). Wilcoxon rank-sum tests were used to compare the LSIs and IKDC scores between groups.

Results

There were 30 study participants (19 male, 11 female; median age, 22 years [range, 14-41 years]; median time since surgery, 8 months [range, 6-23 months]), with 15 patients in each group. There were no significant between-group differences in demographic variables or outcomes. LSIs were not significantly different between the QT versus BPTB group, respectively: knee extensor isokinetic strength at 60 deg/s (median, 70 [range, 41-120] vs 68 [range, 37-83]; P = .285), activation (median, 95 [range, 85-111] vs 92 [range, 82-105]; P = .148), cross-sectional area of the vastus medialis (median, 79 [range, 62-104] vs 77 [range, 62-95]; P = .425), single-leg hop test (median, 88 [range, 35-114] vs 77 [range, 49-100]; P = .156), and step length symmetry (median, 99 [range, 93-104] vs 98 [range, 92-103]; P = .653). The median IKDC scores between the QT and BPTB groups were also not significantly different: 82 (range, 67-94) versus 83 (range, 54-94); respectively (P = .683).

Conclusion

Patients with QT autografts demonstrated similar short-term quadriceps recovery and postsurgical outcomes compared with patients with BPTB autografts.

The Role of Blood Flow Restriction Therapy Following Knee Surgery: Expert Opinion

Blood flow restriction (BFR) therapy is becoming increasingly popular in musculoskeletal injury rehabilitation. In particular, this form of therapy is being utilized more often in the postoperative setting following knee surgery, including anterior cruciate ligament reconstruction. BFR therapy provides patients and clinicians an alternative treatment option to standard muscle strengthening and hypertrophy guidelines in the setting of postoperative pain, weakness, and postoperative activity restrictions that contribute to muscle atrophy. The ability to complete exercise in a low load environment and achieve similar physiological adaptations as high-intensity strength training makes this modality appealing. With poor patient-related outcomes associated with continued muscle atrophy, pain, and muscle weakness, some researchers have investigated BFR training postoperatively following arthroscopic knee surgery with promising results. However, owing to the current paucity of research studies, inconsistency among reported protocols, and mixed results, it may be some time before a mass adoption of BFR therapy is made into the world of orthopaedic rehabilitation. Although the current data is inconclusive, we choose to utilize BFR in postoperative knee patients, regardless of weight-bearing status, for whom maintenance of existing muscle mass or improvement of decreased postoperative strength levels is important. Therefore, the purpose of this expert opinion is to review the background of BFR, describe the clinical evidence of BFR following knee surgery, and report the authors' current recommendations for application of BFR postoperatively.

Comparison of the large muscle group widths of the pelvic limb in seven breeds of dogs

Orthopaedic diseases are common in the pelvic limbs of dogs, and reference values for large muscle groups of the pelvic limb may aid in diagnosis such diseases. As such, the objective of this study was to compare the large muscle groups of the pelvic limb in seven breeds of dogs. A total of 126 dogs from different breeds were included, and the widths of the quadriceps, hamstring and gastrocnemius muscles were measured from images of the lateral radiographies. The width of the quadriceps was not different between the breeds, but the widths of the hamstring and gastrocnemius muscles were significantly different between the breeds. The widest hamstring and gastrocnemius muscles were seen in the Rottweilers and the Boxers, respectively. The narrowest hamstring and gastrocnemius muscles were seen in the Belgian Malinois and the Golden retrievers, respectively. All ratios between the measured muscles differed significantly between the breeds. Doberman pinschers and Belgian Malinois had the highest ratio of gastrocnemius width:hamstring width. Doberman pinschers had also the highest ratio of quadriceps width:hamstring width. German shepherds had the highest ratio of gastrocnemius width:quadriceps width. The lowest ratios of quadriceps width:hamstring width were determined in the German shepherds. The ratios of the muscle widths may be used as reference values to assess muscular atrophy or hypertrophy in cases of bilateral or unilateral orthopaedic diseases of the pelvic limbs. Further studies are required to determine the widths and ratios of the large muscle groups of the pelvic limbs in other dog breeds.

Enhanced skeletal muscle regrowth and remodelling in massaged and contralateral non-massaged hindlimb

KEY POINTS

Muscle fibre cross sectional area is enhanced with massage in the form of cyclic compressive loading during regrowth after atrophy. Massage enhances protein synthesis of the myofibrillar and cytosolic, but not the mitochondrial fraction, in muscle during regrowth. Focal adhesion kinase activation and satellite cell number are elevated in muscles undergoing massage during regrowth. Muscle fibre cross sectional area and protein synthesis of the myofibrillar fraction, but not DNA synthesis, are elevated in muscle of the contralateral non-massaged limb. Massage in the form of cyclic compressive loading is a potential anabolic intervention during muscle regrowth after atrophy.

ABSTRACT

Massage, in the form of cyclic compressive loading (CCL), is associated with multiple health benefits, but its potential anabolic effect on atrophied muscle has not been investigated. We hypothesized that the mechanical activity associated with CCL induces an anabolic effect in skeletal muscle undergoing regrowth after a period of atrophy. Fischer-Brown Norway rats at 10 months of age were hindlimb unloaded for a period of 2 weeks. The rats were then allowed reambulation with CCL applied at a 4.5 N load at 0.5 Hz frequency for 30 min every other day for four bouts during a regrowth period of 8 days. Muscle fibre cross sectional area was enhanced by 18% with massage during regrowth compared to reloading alone, and this was accompanied by elevated myofibrillar and cytosolic protein as well as DNA synthesis. Focal adhesion kinase phosphorylation indicated that CCL increased mechanical stimulation, while a higher number of Pax7+ cells likely explains the elevated DNA synthesis. Surprisingly, the contralateral non-massaged limb exhibited a comparable 17% higher muscle fibre size compared to reloading alone, and myofibrillar protein synthesis, but not DNA synthesis, was also elevated. We conclude that massage in the form of CCL induces an anabolic response in muscles regrowing after an atrophy-inducing event. We suggest that massage can be used as an intervention to aid in the regrowth of muscle lost during immobilization.

Perioperative Testosterone Supplementation Increases Lean Mass in Healthy Men Undergoing Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial

Background:

Rehabilitation after repair of the anterior cruciate ligament (ACL) is complicated by the loss of leg muscle mass and strength. Prior studies have shown that preoperative rehabilitation may improve muscle strength and postoperative outcomes. Testosterone supplementation may likewise counteract this muscle loss and potentially improve clinical outcomes.

Purpose:

The purpose was to investigate the effect of perioperative testosterone administration on lean mass after ACL reconstruction in men and to examine the effects of testosterone on leg strength and clinical outcome scores. It was hypothesized that testosterone would increase lean mass and leg strength and improve clinical outcome scores relative to placebo.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

Male patients (N = 13) scheduled for ACL reconstruction were randomized into 2 groups: testosterone and placebo. Participants in the testosterone group received 200 mg of intramuscular testosterone weekly for 8 weeks beginning 2 weeks before surgery. Participants in the placebo group received saline following the same schedule. Both groups participated in a standard rehabilitation protocol. The primary outcome was the change in total lean body mass at 6 and 12 weeks. Secondary outcomes were extensor muscle strength, Tegner activity score, and Knee injury and Osteoarthritis Outcome Score.

Results:

There was an increase in lean mass of a mean 2.7 ± 1.7 kg at 6 weeks postoperatively in the testosterone group compared with a decrease of a mean 0.1 ± 1.5 kg in the placebo group (P = .01). Extensor muscle strength of the uninjured leg also increased more from baseline in the testosterone group (+20.8 ± 25.6 Nm) compared with the placebo group (–21.4 ± 36.7 Nm) at 12 weeks (P = .04). There were no significant between-group differences in injured leg strength or clinical outcome scores. There were no negative side effects of testosterone noted.

Conclusion:

Perioperative testosterone supplementation increased lean mass 6 weeks after ACL reconstruction, suggesting that this treatment may help minimize the effects of muscle atrophy associated with ACL injuries and repair. This study was not powered to detect differences in strength or clinical outcome scores to assess the incidence of testosterone-related adverse events.

Clinical Relevance:

Supraphysiological testosterone supplementation may be a useful adjunct therapy for counteracting muscle atrophy after ACL reconstruction. Further investigation is necessary to determine the safety profile and effects of perioperative testosterone administration on leg strength and clinical outcomes after surgery.

Registration:

NCT01595581 (ClinicalTrials.gov).

Quadriceps function relates to muscle size following ACL reconstruction

It remains unclear what role reduced volume and cross-section area (CSA) of individual quadriceps muscles may play in persistent quadriceps weakness and more global dysfunction following ACL reconstruction (ACLR). The purpose of this investigation was to establish the relationship between cross-sectional area of the quadriceps muscle group and measures of knee related and quadriceps function following ACLR. Thirty participants with a history of primary, unilateral ACLR experiencing persistent quadriceps activation failure participated in this cohort study. Clinical factors including International Knee Documentation Committee (IKDC) score, normalized knee extension MVIC torque (Nm/kg) and quadriceps central activation ratio (CAR, %) were assessed in addition to CSA. Quadriceps CSA was measured via magnetic resonance imaging (MRI; Siemens Avanto 1.5T). Quadriceps CSA (cm(2) ) and quadriceps volume (cm(3) ) as well as individual muscle estimates were identified within a 10 cm mid-thigh capture area. Pearson's product-moment correlation coefficients (r) established relationships between CSA and all other variables. Stepwise linear regression established which CSA factors were able to successfully predict clinical factors. Knee extension MVIC torque was strongly correlated with Vastus Intermedius (VI; r =  0.857, p < 0.001) CSA as well as partial VI (r = 0.849, p < 0.001) and quadriceps (r = 0.830, p < 0.001) volume. Partial VI (r = 0.365, p = 0.047) volume was weakly correlated with IKDC score. Knee extension MVIC torque was strongly predicted using VI CSA alone (R(2)  = 0.725) or in combination with Vastus Medialis CSA (VM; R(2)  = 0.756). Statement of Clinical Significance: Atrophy of the VI and VM muscles negatively impacts knee extension strength following ACLR. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1656-1662, 2016.

An Assessment of Rehabilitation Protocols following Anterior Cruciate Ligament Reconstruction: A Systematic Review

The present study provided a systematic review with meta-analysis of randomized controlled trials involving the effectiveness of various rehabilitation methods that have been implemented for the treatment of anterior cruciate ligament reconstruction (ACLR). The review of the literature revealed the following as evidence for effective ACLR rehabilitation: early intervention strategy focused on restoring range of motion, muscle strength, and ligament stability with the utilization of closed kinetic chain exercises. The literature supports the use of dynamic intraligamentary stabilization, which should also be implemented in the rehabilitation protocol within the first three months after surgery. The research suggests that the patient should undergo at least 30-90 minutes of cryotherapy immediately following ACLR surgery. There is also some evidence regarding the effectiveness of neuromuscular rehabilitation training programs, but further investigations are needed. Future research should consider the timing of rehabilitation as well as supplemental rehabilitation exercises to continue to improve the quality of care delivered to patients following ACLR.

The effectiveness of pre-operative exercise physiotherapy rehabilitation on the outcomes of treatment following anterior cruciate ligament injury: a systematic review

OBJECTIVE

To evaluate the effectiveness of pre-operative exercise physiotherapy rehabilitation on the outcomes of treatment following anterior cruciate ligament injury.

METHODS

The following databases were searched: PubMed, Ovid, The Cochrane Library and Web of Science. Studies published between the inception of the databases and December 2015 were sought using appropriate keywords in various combinations. This search was supplemented with a manual search of the references of selected studies. Studies were assessed for methodological quality using the Physiotherapy Evidence Database scale.

RESULTS

A total of 500 studies were identified, of which eight studies met the inclusion criteria and were included in the present review. The average Physiotherapy Evidence Database score for the studies included was 5.8, which reflects an overall moderate methodological quality. The eight studies investigated a total of 451 subjects of which 71% ( n=319) were males. The age of the participants in the eight studies ranged from 15 to 57 years. The duration of the intervention in the studies ranged from 3 to 24 weeks. This review found that pre-operative physiotherapy rehabilitation is effective for improving the outcomes of treatment following anterior cruciate ligament injury, including increasing knee-related function and improving muscle strength. However, whilst there was a significant improvement in quality of life from baseline following intervention, no significant difference in quality of life was found between the control and intervention groups.

CONCLUSIONS

There is evidence to suggest that pre-operative physiotherapy rehabilitation is beneficial to patients with anterior cruciate ligament injury.

Intermittent blood flow restriction does not reduce atrophy following anterior cruciate ligament reconstruction

BACKGROUND

A previous study has reported a 50% reduction in disuse atrophy of the quadriceps during the first 14 days after anterior cruciate ligament (ACL) reconstruction. A follow-up trial is needed to confirm these promising results. The present study aims to investigate the effect of an occlusion stimulus on quadriceps atrophy after ACL reconstruction.

METHODS

A total of 24 subjects participated in the study. They were randomized into two groups. Starting the 2nd day after surgery, the occlusion group received an occlusion stimulus for 5 min, followed by removal of the occlusive pressure for 3 min. This was repeated five times in one training session, twice daily. During the period of occlusive stimulus, the subjects performed 20 low load exercises for the quadriceps. The control group followed the same exercise protocol, but without the occlusion stimulus. Changes in quadriceps anatomical cross section area (ACSA) were measured using axial magnetic resonance (MR) images at 40% and 50% of the length of the femur.

RESULTS

Both groups had a significant reduction of quadriceps ACSA from 2 days before surgery to 16 days after surgery. During the intervention period, the occlusion group lost 13.8% ± 1.1% (mean ± SEM) and the control group lost 13.1% ± 1.0% of their quadriceps ACSA, respectively. There was no significant difference between the occlusion and control groups with regards to atrophy of the quadriceps muscles.

CONCLUSION

In conflict with other studies using a similar protocol, application of blood flow restriction the first 14 days after ACL reconstruction did not reduce quadriceps ACSA muscle atrophy measured by MR in a population of athletes.

Enhanced knee joint function due to accelerated rehabilitation exercise after anterior cruciate ligament reconstruction surgery in Korean male high school soccer players

This study was conducted on Korean male high school soccer players who underwent anterior cruciate ligament reconstruction (ACLR) to identify the effects of an accelerated rehabilitation exercise (ARE) program on knee joint isometric strength, thigh circumference, Lysholm score, and active balance agility. We assigned eight test participants each to a physical therapy group (PTG) and an accelerated rehabilitation exercise group (AREG), and compared differences between the groups. Both the PTG and AREG showed significant increases in 30° away and 60° toward isometric strength after treatment. In addition, significant differences were observed in these strength tests between the two groups. Both groups also showed significant increases in thigh circumference, Lysholm score, and active balance agility after treatment, but no significant differences were observed between the two groups. We conclude that the ARE treatment was more effective for improving isometric strength of the knee joint than that of physical therapy, and that an active rehabilitation exercise program after ACLR had positive effects on recovery performance of patients with an ACL injury and their return to the playing field.

Use of B-mode ultrasonography for measuring femoral muscle thickness in dogs

Assessment of muscle mass is important for evaluating muscle function and rehabilitation outcomes. Ultrasound has recently been successfully used to estimate muscle mass in humans by measuring muscle thickness. This study attempted to standardize procedures for measuring femoral muscle thickness ultrasonographically, as well as quantify the reliability and validity of ultrasound evaluations of muscle thickness compared to measurements made by magnetic resonance imaging (MRI) in dogs. We evaluated the quadriceps femoris (QF), biceps femoris (BF), semitendinosus (ST) and semimembranosus (SM) muscles of 10 clinically healthy Beagle dogs. Scans were taken in 5 different sections divided equally between the greater trochanter and proximal patella. MRI was performed, followed by T1-weighted and contrast-enhanced T1-weighted imaging. Muscle cross-sectional area (CSA) was measured with MRI, and muscle thickness was measured with MRI and ultrasonography. The thickness of the QF, BF and ST muscles as measured by ultrasound at slices 1–3 (from the proximal end to the middle of the femur), 2–4 (middle of the femur) and 2 (more proximal than the middle of the femur), respectively, was correlated with muscle thickness and CSA as measured by MRI. These sites showed a flat interface between muscle and transducer and were situated over belly muscle. No correlation between measurement types was seen in SM muscle. We must confirm this assessment method for various breeds, sizes, ages and muscle pathologies in dogs, thereby confirming that muscle thickness as measured ultrasonographically can reflect muscle function.

Effect of knee angle on quadriceps strength and activation after anterior cruciate ligament reconstruction

Quadriceps strength and activation deficits after anterior cruciate ligament (ACL) injury or surgery are typically evaluated at joint positions that are biomechanically advantageous to the quadriceps muscle. However, the effect of knee joint position and the associated changes in muscle length on strength and activation is currently unknown in this population. Here, we examined the effect of knee angle on quadriceps strength, activation, and electrically evoked torque in individuals with ACL reconstruction. Furthermore, we evaluated whether knee angle mediated the relationship between quadriceps weakness and functional performance after ACL reconstruction. Knee strength and activation were tested bilaterally at 90° and 45° of knee flexion in 11 subjects with ACL reconstruction using an interpolated triplet technique. The magnitude of electrically evoked torque at rest was used to quantify peripheral muscle contractile property changes, and the single-leg hop for distance test was used to evaluate functional performance. The results indicated that although quadriceps strength deficits were similar between knee angles, voluntary activation deficits were significantly higher in the reconstructed leg at 45° of knee flexion. On the contrary, the side-to-side evoked torque at rest ratio [i.e., (reconstructed/nonreconstructed) × 100] was significantly lower at 90° than at 45° of knee flexion. The association between quadriceps strength and functional performance was stronger at 45° of knee flexion. The results provide novel evidence that quadriceps activation is selectively affected at 45° of knee flexion and emphasize the importance of assessing quadriceps strength and activation at this position when feasible because it better captures activation deficits.

Serum cytokines and muscle strength after anterior cruciate ligament surgery are not modulated by high-doses of vitamins E (α- and γ-tocopherol's) and C

The purpose of this investigation was to identify if supplemental vitamin E (consisting of α- and γ-tocopherol's) and C modulate serum cytokine and muscle strength following an ACL injury and surgery. Subjects were randomly assigned to one of two groups: (1) placebo (n=14) or (2) vitamins E (α-[600m g RRR-α-tocopherol, αT] and γ-[600 mg of RRR-γT]) and C (1000 mg ascorbic acid, AA) (EC; n=15). Supplements were taken daily starting ∼2-wk prior to and concluding 16-wk after surgery. Fasting blood samples were obtained and single-leg peak isometric force measurements were performed at baseline (prior to supplementation), before surgery (∼120-min - blood draw only), and 8-wk, 12-wk, and 16-wk after surgery. αT, γT, AA, and cytokines were measured in each blood sample, and peak isometric force was measured on the injured and non-injured legs separately at each testing session. An exercise protocol consisting of repetitive knee and hip extension and flexion contractions to exhaustion was performed on the injured limb at 16-wk. Vitamin E and C supplementation significantly (all p<0.05) increased plasma αT (∼40%), γT (∼160%), and AA (∼50%) concentrations. Serum cytokine concentrations, peak isometric force, and time to exhaustion during the exercise protocol were not significantly different between groups. Based on these findings, we conclude that vitamin E and C supplementation increases their endogenous levels without minimizing muscular weakness or modulating serum cytokine concentrations after ACL surgery.

Agent-based computational model investigates muscle-specific responses to disuse-induced atrophy

Skeletal muscle is highly responsive to use. In particular, muscle atrophy attributable to decreased activity is a common problem among the elderly and injured/immobile. However, each muscle does not respond the same way. We developed an agent-based model that generates a tissue-level skeletal muscle response to disuse/immobilization. The model incorporates tissue-specific muscle fiber architecture parameters and simulates changes in muscle fiber size as a result of disuse-induced atrophy that are consistent with published experiments. We created simulations of 49 forelimb and hindlimb muscles of the rat by incorporating eight fiber-type and size parameters to explore how these parameters, which vary widely across muscles, influence sensitivity to disuse-induced atrophy. Of the 49 muscles modeled, the soleus exhibited the greatest atrophy after 14 days of simulated immobilization (51% decrease in fiber size), whereas the extensor digitorum communis atrophied the least (32%). Analysis of these simulations revealed that both fiber-type distribution and fiber-size distribution influence the sensitivity to disuse atrophy even though no single tissue architecture parameter correlated with atrophy rate. Additionally, software agents representing fibroblasts were incorporated into the model to investigate cellular interactions during atrophy. Sensitivity analyses revealed that fibroblast agents have the potential to affect disuse-induced atrophy, albeit with a lesser effect than fiber type and size. In particular, muscle atrophy elevated slightly with increased initial fibroblast population and increased production of TNF-α. Overall, the agent-based model provides a novel framework for investigating both tissue adaptations and cellular interactions in skeletal muscle during atrophy.

Randomized control trial to evaluate the effects of acute testosterone administration in men on muscle mass, strength, and physical function following ACL reconstructive surgery: rationale, design, methods

Background

The anterior cruciate ligament (ACL) is one of four major ligaments in the knee that provide stability during physical activity. A tear in the ACL is characterized by joint instability that leads to decreased activity, knee dysfunction, reduced quality of life and a loss of muscle mass and strength. While rehabilitation is the standard-of-care for return to daily function, additional surgical reconstruction can provide individuals with an opportunity to return to sports and strenuous physical activity. Over 200,000 ACL reconstructions are performed in the United States each year, and rehabilitation following surgery is slow and expensive. One possible method to improve the recovery process is the use of intramuscular testosterone, which has been shown to increase muscle mass and strength independent of exercise. With short-term use of supraphysiologic doses of testosterone, we hope to reduce loss of muscle mass and strength and minimize loss of physical function following ACL reconstruction compared to standard-of-care alone.

Methods/design

This study is a double-blinded randomized control trial. Men 18–50 years of age, scheduled for ACL reconstruction are randomized into two groups. Participants randomized to the testosterone group receive intramuscular testosterone administration once per week for 8 weeks starting 2 weeks prior to surgery. Participants randomized to the control group receive a saline placebo intramuscularly instead of testosterone. Lean mass, muscle strength and physical function are measured at 5 time points: 2 weeks pre-surgery, 1 day pre-surgery, and 6, 12, 24 weeks post-surgery. Both groups follow standard-of-care rehabilitation protocol.

Discussion

We believe that testosterone therapy will help reduce the loss of muscle mass and strength experienced after ACL injury and reconstruction. Hopefully this will provide a way to shorten the rehabilitation necessary following ACL reconstruction. If successful, testosterone therapy may also be used for other injuries involving trauma and muscle atrophy.

Trial registration

NTC01595581, Registration: May 8, 2012

Documentation of strength training for research purposes after ACL reconstruction

PURPOSE

The purpose of this systematic literature review was to evaluate strength training protocol documentation during rehabilitation after anterior cruciate ligament (ACL) reconstruction. The aim was further to present recommendations concerning what components (i.e. methods, principles and training variables) could be considered vital to document when it comes to strength training for research purposes after ACL reconstruction.

METHODS

A search of the PUBMED/MEDLINE, CINAHL and SportDiscus databases was made of relevant literature relating to strength training after ACL reconstruction. The database search was based on relevant medical subject headings terms (strength/resistance/weight training, anterior cruciate ligament reconstruction/rehabilitation). The literature was reviewed regarding the way methods and variables were documented in strength training protocols during rehabilitation after ACL reconstruction in peer-reviewed original prospective articles.

RESULTS

The systematic literature search identified 139 citations published between January 1983 and May 2012. Six studies contained a strength training programme-part of the rehabilitation protocol after ACL reconstruction that met the inclusion criteria. Basic information (i.e. training frequency, intensity, volume, progression or the duration of the training period) regarding the strength training protocols used during rehabilitation after ACL reconstruction was not documented in full in four of the studies.

CONCLUSION

The results clearly indicate the need of a more standardised and detailed way of documenting strength training for research purposes after ACL reconstruction in order to increase the value of future studies on this subject. This review gives recommendations on strength training protocol documentation after ACL reconstruction to facilitate this goal.

LEVEL OF EVIDENCE

IV.

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.

Muscle strength and hop performance criteria prior to return to sports after ACL reconstruction

PURPOSE

The purpose of this article is to present recommendations for new muscle strength and hop performance criteria prior to a return to sports after anterior cruciate ligament (ACL) reconstruction.

METHODS

A search was made of relevant literature relating to muscle function, self-reported questionnaires on symptoms, function and knee-related quality of life, as well as the rate of re-injury, the rate of return to sports and the development of osteoarthritis after ACL reconstruction. The literature was reviewed and discussed by the European Board of Sports Rehabilitation in order to reach consensus on criteria for muscle strength and hop performance prior to a return to sports.

RESULTS

The majority of athletes that sustain an (ACL) injury do not successfully return to their pre-injury sport, even though most athletes achieve what is considered to be acceptable muscle function. On self-reported questionnaires, the athletes report high ratings for fear of re-injury, low ratings for their knee function during sports and low ratings for their knee-related quality of life.

CONCLUSION

The conclusion is that the muscle function tests that are commonly used are not demanding enough or not sensitive enough to identify differences between injured and non-injured sides. Recommendations for new criteria are given for the sports medicine community to consider, before allowing an athlete to return to sports after an ACL reconstruction.

Do changes in dynamic plantar pressure distribution, strength capacity and postural control after intra-articular calcaneal fracture correlate with clinical and radiological outcome?

Fractures of the calcaneus are often associated with serious permanent disability, a considerable reduction in quality of life, and high socio-economic cost. Although some studies have already reported changes in plantar pressure distribution after calcaneal fracture, no investigation has yet focused on the patient's strength and postural control.

METHOD

60 patients with unilateral, operatively treated, intra-articular calcaneal fractures were clinically and biomechanically evaluated >1 year postoperatively (physical examination, SF-36, AOFAS score, lower leg isokinetic strength, postural control and gait analysis including plantar pressure distribution). Results were correlated to clinical outcome and preoperative radiological findings (Böhler angle, Zwipp and Sanders Score).

RESULTS

Clinical examination revealed a statistically significant reduction in range of motion at the tibiotalar and the subtalar joint on the affected side. Additionally, there was a statistically significant reduction of plantar flexor peak torque of the injured compared to the uninjured limb (p<0.001) as well as a reduction in postural control that was also more pronounced on the initially injured side (standing duration 4.2±2.9s vs. 7.6±2.1s, p<0.05). Plantar pressure measurements revealed a statistically significant pressure reduction at the hindfoot (p=0.0007) and a pressure increase at the midfoot (p=0.0001) and beneath the lateral forefoot (p=0.037) of the injured foot. There was only a weak correlation between radiological classifications and clinical outcome but a moderate correlation between strength differences and the clinical questionnaires (CC 0.27-0.4) as well as between standing duration and the clinical questionnaires. Although thigh circumference was also reduced on the injured side, there was no important relationship between changes in lower leg circumference and strength suggesting that measurement of leg circumference may not be a valid assessment of maximum strength deficits. Self-selected walking speed was the parameter that showed the best correlation with clinical outcome (AOFAS score).

CONCLUSION

Calcaneal fractures are associated with a significant reduction in ankle joint ROM, plantar flexion strength and postural control. These impairments seem to be highly relevant to the patients. Restoration of muscular strength and proprioception should therefore be aggressively addressed in the rehabilitation process after these fractures.

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.

Fratura de patela com ruptura do tendão patelar em um cão: relato de caso

Relatou-se a ocorrência de fratura patelar associada à ruptura do tendão patelar em um cão sem raça definida, macho, atendido em um hospital veterinário escola. A técnica utilizada foi a combinação de fixação óssea com fio de Kirschner e aplicação de banda de tensão, recomendada em fraturas transversais da patela. Para reparar a lesão do tendão patelar, realizou-se a sutura tipo Kessler modificada com fio de náilon 0,80mm. No retorno do paciente, 150 dias após o procedimento cirúrgico, havia processo cicatricial ósseo avançado da patela. Concluiu-se que as medidas adotadas para reparação da lesão foram eficazes

Vitamin E and C supplementation does not ameliorate muscle dysfunction after anterior cruciate ligament surgery

Muscle atrophy and weakness are predominant impairments after anterior cruciate ligament (ACL) surgical repair. We tested the hypothesis that vitamin E and C supplementation will improve recovery from ACL injury. Men undergoing elective ACL surgery were randomly assigned to twice-daily supplements of either antioxidants (AO; vitamins E and C, n=10) or matching placebos (n=10) from 2 weeks before until 3 months after surgery. Each subject provided several fasting blood draws, two muscle biopsies from the thigh muscle of the injured limb, and strength and thigh circumference measurements of the lower limbs. Muscle atrophy was apparent in both groups before and several days after surgery. Compared with baseline measurements, peak isometric force of the injured limb increased significantly (P<0.05) by 3 months postsurgery in both treatment groups; however, AO supplementation did not augment these strength gains. By contrast, baseline plasma ascorbic acid concentrations correlated (r=0.59, P=0.006) with subsequent improvement in the strength of the injured limb. In summary, vitamin E and C supplementation was ineffective in potentiating the improvement in force production by the injured limb; however, baseline vitamin C status was associated with beneficial outcomes in strength, suggesting that long-term dietary habits are more effective than short-term supplements.

3D-patient-specific geometry of the muscles involved in knee motion from selected MRI images

Patient-specific muscle geometry is not only an interesting clinical tool to evaluate different pathologies and treatments, but also provides an essential input data to more realistic musculoskeletal models. The protocol set up in our study provided the 3D-patient-specific geometry of the 13 main muscles involved in the knee joint motion from a few selected magnetic resonance images (MRIs). The contours of the muscles were identified on five to seven MRI axial slices. A parametric-specific object was then constructed for each muscle and deformed to fit those contours. The 13 muscles were obtained within 1 h, with less than 5% volume error and 5 mm point-surface error (2RMS). From this geometry, muscle volumes and volumic fractions of asymptomatic and anterior cruciate ligament deficient subjects could easily be computed and compared to previous studies. This protocol provides an interesting precision/time trade-off to obtain patient-specific muscular geometry.