Rehabilitation after anterior cruciate ligament reconstruction: criteria-based progression through the return-to-sport phase

Effect of plyometric training on lower limb biomechanics in females

OBJECTIVE

To verify the effects of plyometric training on lower limb kinematics, eccentric hip and knee torques, and functional performance.

DESIGN

Cohort study.

SETTING

Research laboratory.

PARTICIPANTS

Thirty-six females were divided into a training group (TG; n = 18) that carried out the plyometric training for 8 weeks, and a control group (CG; n = 18) that carried out no physical training.

INTERVENTIONS

Twenty-four plyometric training sessions during approximately 8 weeks with 3 sessions per week on alternate days.

MAIN OUTCOMES MEASURES

Lower limb kinematics (maximum excursion of hip adduction, hip medial rotation, and knee abduction during the single leg squat), eccentric hip (abductor, adductor, medial, and lateral rotator) isokinetic peak torques and knee (flexor and extensor) isokinetic peak torques, and functional performance (triple hop test and the 6-m timed hop test).

RESULTS

After 8 weeks, only the TG significantly reduced the values for the maximum excursion of knee abduction (P = 0.01) and hip adduction (P < 0.001). Similarly, only the TG significantly increased the eccentric hip abductor (P < 0.001) and adductor (P = 0.01) torques. Finally, only the TG significantly increased the values in the triple hop test (P < 0.001) and significantly decreased the values in the 6-m timed hop test (P < 0.001) after intervention.

CONCLUSION

Plyometric training alters lower limb kinematics and increases eccentric hip torque and functional performance, suggesting the incorporation of these exercises in preventive programs for ACL injuries.

Assessment of Kinematic Asymmetry for Reduction of Hamstring Injury Risk

Context:

Kinematic asymmetry is believed to be associated with elevated risk for muscle injury, but little is known about the links between hamstring injuries and asymmetry of sprinting mechanics.

Objective:

To evaluate the value of kinematic analysis of sprinting for the detection of injury-related asymmetry in athletes with a history of hamstring strain.

Participants:

Six sub-elite male sprinters, including two who sustained a hamstring strain injury.

Outcome Measures:

Absolute differences between left and right symmetry indices and symmetry angles were both calculated for ground contact time and selected angular displacements. Measurements were acquired at foot strike, during the stance phase, and at toe-off.

Results:

At toe-off, injured athletes exhibited greater knee flexion and less hip extension for the injured extremity compared to the uninjured extremity. Symmetry indices for these variables markedly exceeded an established 15% threshold for clinically relevant asymmetry. Each of the uninjured athletes exhibited a high degree of symmetry for all parameters, with mean values for symmetry indices significantly lower than the 15% threshold (P < 0.05).

Conclusions:

Kinematic analysis of sprinting asymmetry appears to be valuable for identification of elevated risk for hamstring injury.

Neuromuscular training to target deficits associated with second anterior cruciate ligament injury

SYNOPSIS

Successful return to previous level of activity following anterior cruciate ligament (ACL) reconstruction is not guaranteed, and the prevalence of second ACL injury may be as high as 30%. In particular, younger athletes who return to sports activities within the first several months after ACL reconstruction may be at significantly greater risk of a second ACL rupture compared to older, less active individuals. Significant neuromuscular deficits and functional limitations are commonly identified in athletes following ACL reconstruction, and these abnormal movement and neuromuscular control profiles may be both residual of deficits existing prior to the initial injury and exacerbated by the injury and subsequent ACL reconstruction surgery. Following ACL reconstruction, neuromuscular deficits are present in both the surgical and nonsurgical limbs, and accurately predict second-ACL injury risk in adolescent athletes. While second ACL injury in highly active individuals may be predicated on a number of modifiable and nonmodifiable factors, clinicians have the greatest potential to address the modifiable postsurgical risk factors through targeted neuromuscular interventions. This manuscript will (1) summarize the neuromuscular deficits commonly identified at medical discharge to return to sport, (2) provide the evidence underlying second-ACL injury risk factors, (3) propose a method to assess the modifiable deficits related to second-ACL injury risk, and (4) outline a method of intervention to prevent second ACL injury. The program described in this clinical commentary was developed with consideration for the modifiable factors related to second-injury risk, the principles of motor learning, and careful selection of the exercises that may most effectively modify aberrant neuromuscular patterns. Future validation of this evidence-based, late-phase rehabilitation program may be a critical factor in maximizing return-to-activity success and reduction of second-injury risk in highly active individuals.

LEVEL OF EVIDENCE

Therapy, level 5.

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.

Gait patterns differ between ACL-reconstructed athletes who pass return-to-sport criteria and those who fail

BACKGROUND

The current standard of practice for an athlete to return to sport after anterior cruciate ligament (ACL) reconstruction is varied. Attempt to return to activity is typically advised 6 months after surgery, but functional performance deficits and gait abnormalities are often still evident and may have important implications on future function.

HYPOTHESIS

When comparing the involved and uninvolved limbs, patients who failed return-to-sport (RTS) criteria would demonstrate (1) smaller peak knee angles, extensor moments, and peak power absorption at the knee of the involved limb and (2) larger peak hip angles, extensor moments, and peak power generation of the involved limb.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 42 patients completed functional and biomechanical gait assessment 6 months after ACL reconstruction. Functional testing involved an isometric quadriceps strength test, 4 single-legged hop tests, and 2 self-report questionnaires. Three-dimensional motion analysis was used to measure sagittal plane kinematics and kinetics of the hip and knee. A mixed-model analysis of variance and post hoc t tests were used to compare the limb symmetry of those who passed and those who did not pass RTS criteria. Minimal clinically important differences were calculated from healthy gait data and used to further define meaningful limb asymmetries.

RESULTS

Twenty of the 42 (48%) patients passed RTS criteria 6 months after ACL reconstruction. Patients who did not pass the criteria demonstrated statistically significant differences between limbs on all kinematic and kinetic variables at the knee (P ≤ .027). Clinically meaningful asymmetries at the hip were also identified in this group. Only kinetic asymmetries at the knee were identified in the patients who passed RTS criteria.

CONCLUSION

Athletes who demonstrate superior functional performance 6 months after ACL reconstruction may have fewer abnormal and asymmetrical gait behaviors than their poorer performing counterparts. Patients who did not pass RTS criteria not only demonstrated larger kinematic and kinetic asymmetries between limbs but also appeared to use a gait strategy more closely aligned with athletes early after ACL rupture.

CLINICAL RELEVANCE

Poor performance on a battery of functional performance measures may be related to the presence of movement asymmetries in athletes after ACL reconstruction. Objective RTS criteria have the potential to provide information to clinicians who determine when these athletes return to activity, and may aid in the prescription of targeted rehabilitation to address underlying movement asymmetry.

A pivoting elliptical training system for prevention and rehabilitation of musculoskeletal injuries

Knee injuries often occur in pivoting activities but most existing training and rehabilitation devices mainly allow sagittal movements. Thus, a pivoting elliptical training system (PETS) was developed to train and evaluate neuromuscular control in pivoting directions, pivoting neuromuscular control, for prevention and rehabilitation of musculoskeletal injuries. PETS included capabilities of controlling two footplates individually or simultaneously through servomotor controls so that the footplates behaved like two torsional springs, created a slippery surface, or perturbed. Feasibility of PETS to improve pivoting neuromuscular control and neuromechanical properties was demonstrated through experiments on selected healthy individuals. They improved pivoting neuromuscular control in terms of pivoting instability, and reduced reaction time and proprioceptive acuity following training. Thus, PETS can potentially be used as a therapeutic and research tool to investigate underlying mechanisms of pivoting-related injuries and to train human subjects to improve neuromuscular control during risky pivoting movements.

Lessons learned from the last 20 years of ACL-related in vivo-biomechanics research of the knee joint

PURPOSE

Technological advances in recent years have allowed the easy and accurate assessment of knee motion during athletic activities. Subsequently, thousands of studies have been published that greatly improved our understanding of the aetiology, surgical reconstruction techniques and prevention of anterior cruciate ligament (ACL) injuries. The purpose of this review is to summarize the evidence from biomechanical studies on ACL-related research.

METHODS

High-impact articles that enhanced understanding of ACL injury aetiology, rehabilitation, prevention and adaptations after reconstruction were selected.

RESULTS

The importance of restoring internal tibial rotation after ACL reconstruction has emerged in several studies. Criteria-based, individualized rehabilitation protocols have replaced the traditional time-based protocols. Excessive knee valgus, poor trunk control, excessive quadriceps forces and leg asymmetries have been identified as potential high risk biomechanical factors for ACL tear. Injury prevention programmes have emerged as low cost and effective means of preventing ACL injuries, particularly in female athletes.

CONCLUSION

As a result of biomechanical research, clinicians have a better understanding of ACL injury aetiology, prevention and rehabilitation. Athletes exhibiting neuromuscular deficits predisposing them to ACL injury can be identified and enrolled into prevention programmes. Clinicians should assess ACL-reconstructed patients for excessive internal tibial rotation that may lead to poor outcomes.

Symmetry restoration and functional recovery before and after anterior cruciate ligament reconstruction

PURPOSE

The aims of this study were to evaluate the functional recovery before and after ACL reconstruction and to evaluate the sensitivity to change in performance-based and self-reported outcomes prior to and after ACL reconstruction and to determine whether these changes represent clinically relevant improvement.

METHODS

Eighty-three athletes participated in this study. Athletes were tested after an ACL injury, after preoperative training, and 6 and 12 months after ACL reconstruction. Athletes completed quadriceps strength testing, hop testing, and self-reported questionnaires for knee function (International Knee Documentation Committee subjective knee form, Knee Outcome Survey-Activities of Daily Living Scale, and the Global Rating Scale of Perceived Function) at each testing period.

RESULTS

A significant interaction of limb by time was seen in normalized quadriceps strength, and single, triple, and 6-m timed hop, where the involved limb improved more than the uninvolved limb over time. A main effect of time was noted for performance-based limb symmetry indexes and self-reported measures.

CONCLUSION

Limb-to-limb asymmetries are reduced, and normal limb symmetry is restored after perturbation training and aggressive quadriceps strengthening and returned to similar levels 6 months after reconstruction. Performance-based values on the involved limb and self-reported outcomes are sensitive to change over time, and these were clinically relevant improvements.

Anterior cruciate ligament- specialized post-operative return-to-sports (ACL-SPORTS) training: a randomized control trial

Background

Anterior cruciate ligament reconstruction (ACLR) is standard practice for athletes that wish to return to high-level activities; however functional outcomes after ACLR are poor. Quadriceps strength weakness, abnormal movement patterns and below normal knee function is reported in the months and years after ACLR. Second ACL injuries are common with even worse outcomes than primary ACLR. Modifiable limb-to-limb asymmetries have been identified in individuals who re-injure after primary ACLR, suggesting a neuromuscular training program is needed to improve post-operative outcomes. Pre-operative perturbation training, a neuromuscular training program, has been successful at improving limb symmetry prior to surgery, though benefits are not lasting after surgery. Implementing perturbation training after surgery may be successful in addressing post-operative deficits that contribute to poor functional outcomes and second ACL injury risk.

Methods/Design

80 athletes that have undergone a unilateral ACLR and wish to return to level 1 or 2 activities will be recruited for this study and randomized to one of two treatment groups. A standard care group will receive prevention exercises, quadriceps strengthening and agility exercises, while the perturbation group will receive the same exercise program with the addition of perturbation training. The primary outcomes measures will include gait biomechanics, clinical and functional measures, and knee joint loading. Return to sport rates, return to pre-injury level of activity rates, and second injury rates will be secondary measures.

Discussion

The results of this ACL-Specialized Post-Operative Return To Sports (ACL-SPORTS) Training program will help clinicians to better determine an effective post-operative treatment program that will improve modifiable impairments that influence outcomes after ACLR.

Trial registration

Randomized Control Trial NIH 5R01AR048212-07. ClinicalTrials.gov: NCT01773317

Asymmetries in functional hop tests, lower extremity kinematics, and isokinetic strength persist 6 to 9 months following anterior cruciate ligament reconstruction

STUDY DESIGN

Within-subject and between-subject cross-sectional study.

OBJECTIVES

To investigate symmetry in hop-test performance, strength, and lower extremity kinematics 6 to 9 months following anterior cruciate ligament reconstruction (ACLR).

BACKGROUND

Despite the extensive body of literature involving persons following ACLR, no study has comprehensively evaluated measures of strength, lower extremity kinematics, and functional performance of functional hop tests in this population.

METHODS

The subjects were 22 men (mean ± SD age, 28.8 ± 11.2 years) who had ACLR using a bone-patellar tendon-bone autograft 6 to 9 (7.01 ± 0.93) months previously and 22 healthy male controls (age, 24.8 ± 9.1 years). Participants completed a self-report questionnaire and underwent isokinetic strength testing and functional and kinematic assessment of the single-, triple-, and crossover-hop tests. Two-way analyses of variance were used to test for differences between the ACLR group and the control group, and between the 2 lower extremities of the ACLR group.

RESULTS

Compared to the control group, the ACLR group had greater isokinetic knee extension torque deficits at all speeds (P ≤.001) and greater performance asymmetry for all 3 hop tests (P<.001). Compared to the noninvolved lower extremity, the involved lower extremity of the ACLR group exhibited less ankle dorsiflexion and knee flexion in the phases of propulsion (P ≤.014) and landing (P ≤.032). When compared to the control group, the involved lower extremity exhibited less ankle dorsiflexion in the propulsion phase (P<.001) but higher hip flexion in the landing phase (P = .014).

CONCLUSION

Six to 9 months following ACLR, patients continue to demonstrate functional hop and isokinetic knee extension deficits, as well as kinematic differences, during the propulsion and landing phases of the hop tests.

Augmented feedback supports skill transfer and reduces high-risk injury landing mechanics: a double-blind, randomized controlled laboratory study

BACKGROUND

There is a current need to produce a simple, yet effective method for screening and targeting possible deficiencies related to increased anterior cruciate ligament (ACL) injury risk.

HYPOTHESIS

Frontal plane knee angle (FPKA) during a drop vertical jump will decrease upon implementing augmented feedback into a standardized sport training program.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-seven female participants (mean ± SD: age, 14.7 ± 1.5 years; height, 160.9 ± 6.8 cm; weight, 54.5 ± 7.2 kg) were trained over 8 weeks. During each session, each participant received standardized training consisting of strength training, plyometrics, and conditioning. They were also videotaped running on a treadmill at a standardized speed and performing a repeated tuck jump for 10 seconds. Study participants were randomized into 2 groups and received augmented feedback on either their jumping (AF) or sprinting (CTRL) form. Average (mean of 3 trials) and most extreme (trial with greatest knee abduction) FPKA were calculated from 2-dimensional video captured during performance of the drop vertical jump.

RESULTS

After testing, a main effect of time was noted, with the AF group reducing their FPKA average by 37.9% over the 3 trials while the CTRL group demonstrated a 26.7% reduction average across the 3 trials (P < .05). Conversely, in the most extreme drop vertical jump trial, a significant time-by-group interaction was noted (P < .05). The AF group reduced their most extreme FPKA by 6.9° (pretest, 18.4° ± 12.3°; posttest, 11.4° ± 10.1°) on their right leg and 6.5° (pretest, 16.3° ± 14.5°; posttest, 9.8° ± 10.7°) on their left leg, which represented a 37.7% and 40.1% reduction in FPKA, respectively. In the CTRL group, no similar changes were noted in the right (pretest, 16.9° ± 14.3°; posttest, 14.0° ± 12.3°) or left leg (pretest, 9.8° ± 11.1°; posttest, 7.2° ± 9.2°) after training.

CONCLUSION

Providing athletes with augmented feedback on deficits identified by the tuck jump assessment has a positive effect on their biomechanics during a different drop vertical jump task that is related to increased ACL injury risk. The ability of the augmented feedback to support the transfer of skills and injury risk factor reductions across different tasks provides exciting new evidence related to how neuromuscular training may ultimately cross over into retained biomechanics that reduce ACL injuries during sport.

CLINICAL RELEVANCE

The tuck jump assessment's ease of use makes it a timely and economically favorable method to support ACL prevention strategies in young girls.

Return to sport following anterior cruciate ligament reconstruction

Rates of return to pre-injury sport following anterior cruciate ligament (ACL) reconstruction are less than might be expected from standard outcome measures and there appears to be a rapid decline in sporting participation after two to three years. There are many factors that influence whether an individual will return to sport following this type of surgery. They include not only surgical details and rehabilitation, but also social and psychological factors, as well as demographic characteristics. Age is of particular importance with older patients being less likely to resume their pre-injury sport. It is important that future research clearly identify the pre-injury characteristics of the study cohort when investigating return to sport, and also that there is consistent and precise terminology used to report rates of return to sporting activities. Little is known about how to determine when it is safe to return to sport following ACL reconstruction or how to predict whether an athlete will be able to successfully return to sport. Finally, it needs to be recognised that return to sport following ACL reconstruction is associated with a risk of further injury and the development of osteoarthritis.

Current concepts for injury prevention in athletes after anterior cruciate ligament reconstruction

Ligament reconstruction is the current standard of care for active patients with an anterior cruciate ligament (ACL) rupture. Although the majority of ACL reconstruction (ACLR) surgeries successfully restore the mechanical stability of the injured knee, postsurgical outcomes remain widely varied. Less than half of athletes who undergo ACLR return to sport within the first year after surgery, and it is estimated that approximately 1 in 4 to 1 in 5 young, active athletes who undergo ACLR will go on to a second knee injury. The outcomes after a second knee injury and surgery are significantly less favorable than outcomes after primary injuries. As advances in graft reconstruction and fixation techniques have improved to consistently restore passive joint stability to the preinjury level, successful return to sport after ACLR appears to be predicated on numerous postsurgical factors. Importantly, a secondary ACL injury is most strongly related to modifiable postsurgical risk factors. Biomechanical abnormalities and movement asymmetries, which are more prevalent in this cohort than previously hypothesized, can persist despite high levels of functional performance, and also represent biomechanical and neuromuscular control deficits and imbalances that are strongly associated with secondary injury incidence. Decreased neuromuscular control and high-risk movement biomechanics, which appear to be heavily influenced by abnormal trunk and lower extremity movement patterns, not only predict first knee injury risk but also reinjury risk. These seminal findings indicate that abnormal movement biomechanics and neuromuscular control profiles are likely both residual to, and exacerbated by, the initial injury. Evidence-based medicine (EBM) strategies should be used to develop effective, efficacious interventions targeted to these impairments to optimize the safe return to high-risk activity. In this Current Concepts article, the authors present the latest evidence related to risk factors associated with ligament failure or a secondary (contralateral) injury in athletes who return to sport after ACLR. From these data, they propose an EBM paradigm shift in postoperative rehabilitation and return-to-sport training after ACLR that is focused on the resolution of neuromuscular deficits that commonly persist after surgical reconstruction and standard rehabilitation of athletes.

Intra and inter-tester reliability of the tuck jump assessment

OBJECTIVE

To assess the inter-tester and intra-tester reliability of the tuck jump test.

DESIGN

Repeated measures.

SETTING

University Human Performance laboratory.

PARTICIPANTS

Five male and 5 female athletes undertook the Tuck jump test which was then assessed by two independent assessors.

MAIN OUTCOME MEASURES

Score from the video assessment of the tuck jump test by two independent assessors on two separate occasions.

RESULTS

Average percentage of exact agreement (PEA) between the two testers across all scoring criteria for all subjects was 93% (range 80-100%). Both testers were in absolute 100% agreement in 5 out of 10 subjects for all of the scoring criteria. The kappa measure of agreement was k = 0.88 which is very good/excellent. The intra-tester PEA ranged 87.2%-100%, with kappa values of k = 0.86-1.0.

CONCLUSION

The study showed very good-excellent intra-tester and inter-tester reliability for both examiners when comparing their individual scores of the tuck jump test across two analysis sessions. These findings indicate that the proposed tuck jump assessment is reliable to identify abnormal landing mechanics.

Recent advances following anterior cruciate ligament reconstruction: rehabilitation perspectives : Critical reviews in rehabilitation medicine

Injuries to the anterior cruciate ligament are common. Surgical reconstruction is more prevalent than ever. This review article discusses treatment of the patient following surgical reconstruction of the anterior cruciate ligament. Various phases of rehabilitation are discussed with emphasis on early return of passive motion, early weight bearing, bracing, kinetic chain exercises, neuromuscular electrical stimulation and accelerated rehabilitation. Although evidence exists for the treatment of the surgically reconstructed cruciate ligament, more is needed to better define specific timeframes for advancement. Evidence exists that many of these young individuals are not fully returning to unlimited high level activities. This review article presents some of the latest evidence regarding anterior cruciate ligament rehabilitation in an attempt to help the busy clinician understand and relate basic and clinical research to rehabilitation of a patient following reconstruction.

Return to sport following hip injury

Returning to both recreational and competitive sport requires the patient demonstrate the ability to perform their activity without pain, without compensation and without apprehension. The primary focus of this article will be to provide progressive weight bearing phased treatment solutions and both objective and empirical return to play testing suggestions. In addition to satisfactorily completing the test battery with maximum effort, the patient must demonstrate the ability to meet the demands for competing within their respective sport specific environment. Returning to competition will most likely include early phase movement screening and clinical clearance followed by late phase athletic and field testing. Hip structure will and must influence training program design. It is therefore important to recognize that indications for return to play must not focus on a single rehabilitation or exercise variable, but rather a combination of clinical, functional and sport specific demands.

The 2012 ABJS Nicolas Andry Award: The sequence of prevention: a systematic approach to prevent anterior cruciate ligament injury

BACKGROUND

ACL injuries are common, often devastating injuries that lead to short-term disability and long-term sequelae, many of which lack effective treatment, such as osteoarthritis. Therefore, prevention of ACL injury is currently the only effective intervention for these life-altering sequelae, while much of the literature has a rehabilitative focus.

QUESTIONS/PURPOSES

The primary long-term purpose of our multidisciplinary collaborative research team has been to develop ACL injury prevention programs by determining which factors related to ACL injury should be altered, followed by how and when they should be altered.

METHODS

Our primary study objectives were to determine: (1) modifiable risk factors; (2) how these factors can best be modified; and (3) when is the best time to diminish these risk factors. Throughout the course of various studies, we determined the modifiable factors related to increased ACL injury risk. Our research team then focused on exploring numerous ways to augment these factors to maximize prevention efforts. We developed a sequence of prevention models that provide a framework to monitor progress toward the ultimate goal of preventing ACL injuries.

RESULTS

The modifiable factors shown in our work include biomechanical and neuromuscular functionality. When targeted in physical training, we have determined that these factors can be enhanced to effectively aid in the prevention of ACL injuries. Preliminary data have shown that childhood and early adolescence may be valuable periods to implement such training.

CONCLUSIONS

Current evidence has led to the evolution of clinical assessment tools for high-risk athletes and interventions for large populations and specific high-risk individuals. Targeted intervention implemented at the specified developmental stage of highest risk may be the final step toward the maximal reduction of ACL injury risk in young athletes.

No association of time from surgery with functional deficits in athletes after anterior cruciate ligament reconstruction: evidence for objective return-to-sport criteria

BACKGROUND

Release for full activity and return to sport after anterior cruciate ligament reconstruction (ACLR) is often dictated by time from surgery and subjective opinion by the medical team. Temporal guidelines for return to sport may not accurately identify impaired strength and neuromuscular control, which are associated with increased risk for second injury (contralateral and/or ipsilateral limb) after ACLR in athletes.

HYPOTHESES

Athletes undergoing ACLR and returning to sport would demonstrate functional deficits that would not be associated with time from surgery.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-three male (n = 10) and female (n = 23) athletes with unilateral ACLR, who were cleared by a physician to return to their sport after surgery and rehabilitation, performed the single-legged vertical hop test for 10 seconds on a portable force plate. Matched teammates of each patient were recruited to serve as sex-, sport-, and age-matched controls (CTRL; n = 67). Maximum vertical ground-reaction force (VGRF) was measured during each single-limb landing. Single-limb symmetry index (LSI) was calculated as the ratio of the involved divided by uninvolved limb, expressed as a percentage.

RESULTS

The single-limb vertical jump height LSI was reduced in the ACLR group, 89% (95% confidence interval [CI], 83%-95%), compared with the matched CTRL group, 101% (95% CI, 96%-105%; P < .01). The LSI for VGRF normalized to potential energy achieved during flight of the hop was increased in ACLR at 112% (95% CI, 106%-117%) relative to the CTRL group at 102% (95% CI, 98%-106%; P < .01). Linear regression analysis indicated that time from surgery was not associated with limb symmetry deficits in the ACLR group (P > .05; R (2) = .002-.01).

CONCLUSION

Deficits in unilateral force development (vertical jump height) and absorption (normalized VGRF) persist in an athlete's single-limb performance after ACLR and full return to sports. These symmetry deficits appear to be independent of time after reconstruction.

CLINICAL RELEVANCE

On the basis of these results, clinicians should consider assessment of single-limb power performance in the decision-making process for return-to-sport release. Persistent side-to-side asymmetries may increase the risk of contralateral and/or ipsilateral injury.

Single-legged hop tests as predictors of self-reported knee function after anterior cruciate ligament reconstruction: the Delaware-Oslo ACL cohort study

BACKGROUND

Single-legged hop tests are commonly used functional performance measures that can capture limb asymmetries in patients after anterior cruciate ligament (ACL) reconstruction. Hop tests hold potential as predictive factors of self-reported knee function in individuals after ACL reconstruction.

HYPOTHESIS

Single-legged hop tests conducted preoperatively would not and 6 months after ACL reconstruction would predict self-reported knee function (International Knee Documentation Committee [IKDC] 2000) 1 year after ACL reconstruction.

STUDY DESIGN

Cohort study (prognosis); Level of evidence, 2.

METHODS

One hundred twenty patients who were treated with ACL reconstruction performed 4 single-legged hop tests preoperatively and 6 months after ACL reconstruction. Self-reported knee function within normal ranges was defined as IKDC 2000 scores greater than or equal to the age- and sex-specific normative 15th percentile score 1 year after surgery. Logistic regression analyses were performed to identify predictors of self-reported knee function within normal ranges. The area under the curve (AUC) from receiver operating characteristic curves was used as a measure of discriminative accuracy.

RESULTS

Eighty-five patients completed single-legged hop tests 6 months after surgery and the 1-year follow-up with 68 patients classified as having self-reported knee function within normal ranges 1 year after reconstruction. The crossover hop and 6-m timed hop limb symmetry index (LSI) 6 months after ACL reconstruction were the strongest individual predictors of self-reported knee function (odds ratio, 1.09 and 1.10) and the only 2 tests in which the confidence intervals of the discriminatory accuracy (AUC) were above 0.5 (AUC = 0.68). Patients with knee function below normal ranges were over 5 times more likely of having a 6-m timed hop LSI lower than the 88% cutoff than those with knee function within normal ranges. Patients with knee function within normal ranges were 4 times more likely to have a crossover hop LSI greater than the 95% cutoff than those with knee function below normal ranges. No preoperative single-legged hop test predicted self-reported knee function within normal ranges 1 year after ACL reconstruction (all P > .353).

CONCLUSION

Single-legged hop tests conducted 6 months after ACL reconstruction can predict the likelihood of successful and unsuccessful outcome 1 year after ACL reconstruction. Patients demonstrating less than the 88% cutoff score on the 6-m timed hop test at 6 months may benefit from targeted training to improve limb symmetry in an attempt to normalize function. Patients with minimal side-to-side differences on the crossover hop test at 6 months possibly will have good knee function at 1 year if they continue with their current training regimen. Preoperative single-legged hop tests are not able to predict postoperative outcomes.

Clinical Outcomes and Return-to-Sports Participation of 50 Soccer Players After Anterior Cruciate Ligament Reconstruction Through a Sport-Specific Rehabilitation Protocol

Background:

Rehabilitation of soccer players after anterior cruciate ligament reconstruction is usually performed without sport-specific guidelines, and the final phases are often left to the team coaches. The possibility of changing this approach has not yet been investigated.

Study Design:

Case series.

Hypothesis:

A specific rehabilitation protocol for soccer players, with direct control of the last on-field rehabilitation phases, may lead to complete functional recovery.

Methods:

Fifty competitive soccer players who followed a sport-specific rehabilitation protocol for soccer were evaluated during the recovery period until their return to competition. The assessment of the functional outcomes was performed using the Knee Outcome Survey–Sports Activity Scale and isokinetic and aerobic fitness tests.

Results:

The average start of on-field rehabilitation was 90 ± 26 days after surgery; the average time to return to the competitions was 185 ± 52 days. The improvement in the Knee Outcome Survey–Sports Activity Scale during on-field rehabilitation was significant (P < 0.01; from 79 ± 15% to 96 ± 7%). The isokinetic and aerobic fitness tests showed a significant improvement of muscle strength (knee extensors, +55%, P < 0.01; knee flexors, +86%, P < 0.01) and aerobic threshold (+23%, P < 0.01) from the beginning to the end of on-field rehabilitation.

Conclusions:

Adding on-field rehabilitation to the traditional protocols after anterior cruciate ligament reconstruction may safely lead to complete functional recovery in soccer players.

The anatomy of the ACL and its importance in ACL reconstruction

The anterior cruciate ligament (ACL) anatomy is very significant if a reconstruction is attempted after its rupture. An anatomic study should have to address, its biomechanical properties, its kinematics, its position and anatomic correlation and its functional properties. In this review, an attempt is made to summarize the most recent and authoritative tendencies as far as the anatomy of the ACL, and its surgical application in its reconstruction are concerned. Also, it is significant to take into account the anatomy as far as the rehabilitation protocol is concerned. Separate placement in the femoral side is known to give better results from transtibial approach. The medial tibial eminence and the intermeniscal ligament may be used as landmarks to guide the correct tunnel placement in anatomic ACL reconstruction. The anatomic centrum of the ACL femoral footprint is 43 % of the proximal-to-distal length of lateral, femoral intercondylar notch wall and femoral socket radius plus 2.5 mm anterior to the posterior articular margin. Some important factors affecting the surgical outcome of ACL reconstruction include graft selection, tunnel placement, initial graft tension, graft fixation, graft tunnel motion and healing. The rehabilitation protocol should come in phases in order to increase range of motion, muscle strength and leg balance, it should protect the graft and weightbearing should come in stages. The cornerstones of such a protocol remain bracing, controlling edema, pain and range of motion. This should be useful and valuable information in achieving full range of motion and stability of the knee postoperatively. In the end, all these advancements will contribute to better patient outcome. Recommendations point toward further experimental work with in vivo and in vitro studies, in order to assist in the development of new surgical procedures that could possibly replicate more closely the natural ACL anatomy and prevent future knee pathology.

Rate of force development as an adjunctive outcome measure for return-to-sport decisions after anterior cruciate ligament reconstruction

STUDY DESIGN

Descriptive, prospective, longitudinal single-cohort study.

OBJECTIVE

To investigate the rate of force development to 30% (RFD(30)), 50% (RFD(50)), and 90% (RFD(90)) of maximal voluntary isometric contraction (MVIC) as an adjunct outcome measure for determining readiness for return to sport following an anterior cruciate ligament (ACL) reconstruction.

BACKGROUND

One criterion of full recovery following an ACL reconstruction is the ability to achieve 85% or 90% of the maximal strength of the contralateral limb. However, the time required to develop muscular strength in many types of daily and sports activities is considerably shorter than that required to achieve maximal strength. Therefore, in addition to maximal strength, neuromuscular functions such as RFD should also be considered in the definition of recovery.

METHODS

Forty-five male professional soccer players who underwent an ACL reconstruction were recruited. Assessment with the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Tegner score, and KT1000 instrumented arthrometer was performed postinjury/prereconstruction and at 6 and 12 months after ACL reconstruction. MVIC, RFD(30), RFD(50), and RFD(90) testing was performed preinjury, as part of standard preseason assessment, and at 6 and 12 months post-ACL reconstruction.

RESULTS

The average MVIC value 6 months postreconstruction was 97% of the preinjury average value. In contrast, at 6 months, the RFD(30), RFD(50), and RFD(90) values were 80% (P = .04), 77% (P = .03), and 63% (P = .007), respectively, of the preinjury values. The mean RFD values for the reconstructed knee attained or exceeded 90% of the preinjury mean values only at the 12-month post-ACL reconstruction assessment (RFD(30), P = .86; RFD(50), P = .51; RFD(90), P = .56).

CONCLUSION

Despite the near recovery of MVIC strength to preinjury levels, there were still significant deficits in RFD at 6 months post-ACL reconstruction. An RFD similar to the preinjury RFD was achieved at 12 months post-ACL reconstruction, following a rehabilitation program focusing on muscle power. These results suggest that, following an ACL reconstruction, RFD criteria may be a useful adjunct outcome measure for the decision to return athletes to sports. J Orthop Sports Phys Ther 2012;42(9):772-780, Epub 19 July 2012. doi:10.2519/jospt.2012.3780.

Desempenho dos membros inferiores após reconstrução do ligamento cruzado anterior

O desempenho dos membros inferiores em tarefas dinâmicas pode auxiliar no entendimento do controle motor em indivíduos submetidos à reconstrução do LCA. Os objetivos do presente estudo foram investigar o déficit bilateral e a simetria entre os membros inferiores de sujeitos submetidos à reconstrução do LCA e comparar com sujeitos não lesionados. Vinte adultos jovens foram divididos em dois grupos (LCA e controle). A tarefa consistiu na execução do exercício Leg Press (unilateral direita e esquerda e bilateral). O número de repetições máximas (RM) foi quantificado e então o déficit bilateral e o índice de assimetria foram calculados. Os resultados mostraram assimetria no número de RM realizada entre membros no grupo LCA (p=0,005) e apenas o grupo controle apresentou déficit bilateral (p=0,004). Conclui-se que indivíduos que realizaram a reconstrução do LCA apresentaram assimetrias entre membros, sem a presença de déficit bilateral.

Evaluation and management of posterior cruciate ligament injuries

BACKGROUND

Posterior cruciate ligament injuries are increasingly recognized, the result of various sports activities, and while most athletes return to sports the development degenerative joint changes is common.

OBJECTIVE

To provide a synopsis of the current best evidence regarding the recognition and treatment of posterior cruciate ligament injuries.

DESIGN

Structured narrative review.

METHODS

Keyword search of Medline, CINAHL, and PEDro databases for studies published in English from January 1975 to July 2011. Additionally, the reference lists from articles obtained were manually searched for relevant literature.

SUMMARY

The manuscript provides an overview of posterior cruciate ligament injury, discusses diagnostic methods to include radiographic examination techniques, and presents information on surgical and conservative management of PCL injuries.

CONCLUSION

Understanding the mechanism of injuries and most effective examination methods can aide in effective early recognition of PCL injuries. Appropriate management of the patient with PCL deficiency or reconstructed knee will optimize outcomes and potentially affect long term knee function.

Improving lower limb weight distribution asymmetry during the squat using Nintendo Wii Balance Boards and real-time feedback

Weight-bearing asymmetry (WBA) may be detrimental to performance and could increase the risk of injury; however, detecting and reducing it is difficult in a field setting. This study assessed whether a portable and simple-to-use system designed with multiple Nintendo Wii Balance Boards (NWBBs) and customized software can be used to evaluate and improve WBA. Fifteen elite Australian Rules Footballers and 32 age-matched, untrained participants were tested for measures of WBA while squatting. The NWBB and customized software provided real-time visual feedback of WBA during half of the trials. Outcome measures included the mean mass difference (MMD) between limbs, interlimb symmetry index (SI), and percentage of time spent favoring a single limb (TFSL). Significant reductions in MMD (p = 0.028) and SI (p = 0.007) with visual feedback were observed for the entire group data. Subgroup analysis revealed significant reductions in MMD (p = 0.047) and SI (p = 0.026) with visual feedback in the untrained sample; however, the reductions in the trained sample were nonsignificant. The trained group showed significantly less WBA for TFSL under both visual conditions (no feedback: p = 0.015, feedback: p = 0.017). Correlation analysis revealed that participants with high levels of WBA had the greatest response to feedback (p < 0.001, ρ = 0.557). In conclusion, WBA exists in healthy untrained adults, and these asymmetries can be reduced using real-time visual feedback provided by an NWBB-based system. Healthy, well-trained professional athletes do not possess the same magnitude of WBA. Inexpensive, portable, and widely available gaming technology may be used to evaluate and improve WBA in clinical and sporting settings.

Kinematic predictors of subjective outcome after anterior cruciate ligament reconstruction: an in vivo motion analysis study

PURPOSE

The purpose of this study was to test whether rotational knee kinematics during dynamic pivoting activities are predictive of subjective functional outcome (IKDC, Lysholm), objective laxity scores (KT max), and activity levels (Tegner) in patients after anterior cruciate ligament reconstruction (ACLR).

METHODS

Thirty-one patients with single-bundle ACLR were evaluated prospectively with 3D-motion analysis during (1) descending a stairway and pivoting and (2) landing from a jump and pivoting. The side-to-side difference of tibial rotation range of motion (SSDTR) between the ACLR and the contralateral intact knee was calculated for the pivoting phase of each task. Linear regression models were applied with SSDTR, for each task predictors of the subjective IKDC score, Lysholm score, anterior tibial translation, and Tegner activity level.

RESULTS

SSDTR for descending and landing were predictive of the IKDC subjective score (R(2) = 0.46, p < 0.001 and R(2) = 0.40, p < 0.001, respectively) with "medium" effect sizes and of the Lysholm score (R(2) = 0.13, p < 0.05 and R(2) = 0.09, n.s.) with "small" to "none" effect sizes. SSDTR was not predictive of anterior translation or Tegner activity level (n.s.).

CONCLUSIONS

Restoring rotational kinematics during dynamic pivoting activities after ACLR is predictive of functional outcome. The ability of the athlete after ACLR to control tibial rotation during pivoting activities may be predictive of functional outcome.

LEVEL OF EVIDENCE

Case series study. Level IV.

Suggestions from the field for return to sports participation following anterior cruciate ligament reconstruction: American football

Returning an American football player to sport after an anterior cruciate ligament reconstruction is challenging on several fronts. First, there are approximately 15 different positions a football player could play, depending on how specifically you define the positions on the field. Each of these positions has specific demands for optimal size, strength, power, body composition, cardiovascular fitness, and movement. Understanding all of these factors is paramount to returning a football player not only to his sport but also to his specific position. Second, the chaotic, contact-rich nature of the sport requires that heavy demands be placed on the lower extremities to attenuate external contact forces from other players and from ground reaction forces associated with accelerating, decelerating, quick stops and starts, and changing direction. Finally, return to a competitive level of performance is further influenced by playing surface, shoe selection, the equipment the player wears, and various potential psychosocial factors. It is the responsibility of the clinician to provide a progressive and systematic rehabilitation program by first introducing preprogrammed movements that, once mastered, are progressed with elements of more reactive and random movement patterns. The precise nature of this systematic progression of advanced rehabilitation is key in developing return-to-play criteria and, ultimately, in readying an American football player for eventual return to sport and a particular position.

Suggestions from the field for return to sports participation following anterior cruciate ligament reconstruction: soccer

Successful return to play remains a challenge for a soccer player after anterior cruciate ligament reconstruction. In addition to a successful surgical intervention, a soccer-specific functional rehabilitation program is essential to achieve this goal. Soccer-like elements should be incorporated in the early stages of rehabilitation to provide neuromuscular training specific to the needs of the player. Gym-based and, later, field-based drills are gradually intensified and progressed until the player demonstrates the ability to return to team practice. In addition to the recovery of basic attributes such as mobility, flexibility, strength, and agility, the surgically repaired knee must also regain soccer-specific neuromuscular control and conditioning for an effective return to sports. The individual coaching of the player by the sports physiotherapist and compliance with the training program by the player are key factors in the rehabilitation process. To minimize reinjury risk and to maximize the player's career, concepts of soccer-specific injury prevention programs should be incorporated into the training routine during and after the rehabilitation of players post-ACL reconstruction.

Suggestions from the field for return to sports participation following anterior cruciate ligament reconstruction: basketball

The purpose of this paper is to outline the final, functional phases of rehabilitation that address exercises, drills, and return-to-play criteria for the sport of basketball, following anterior cruciate ligament (ACL) reconstruction. ACL injuries can be debilitating and affect the quality of life for recreational and elite athletes alike. Tears of the ACL are common in both male and female basketball players, with a higher incidence rate in females. Incidence of a retear to the existing graft or contralateral knee within 5 years of ACL reconstruction with patellar tendon autograft in young (less than 18 to 25 years of age), active basketball players can be as high as 52%. Reducing the number of ACL injuries or reinjury, of which there are an estimated 80 000 per year at an associated cost of over a billion dollars, can have significant potential long-term fiscal and health benefits. Following surgical reconstruction of the ACL, implementing a tailored rehabilitation protocol can ensure a successful return to sport. When searching the literature for such protocols, clinicians may struggle to find specific exercises, drills, and return-to-play criteria for particular sports. The intent of this manuscript is to present such a rehabilitation protocol for basketball.

Current concepts for rehabilitation and return to sport after knee articular cartilage repair in the athlete

Articular cartilage injury is observed with increasing frequency in both elite and amateur athletes and results from the significant acute and chronic joint stress associated with impact sports. Left untreated, articular cartilage defects can lead to chronic joint degeneration and athletic and functional disability. Treatment of articular cartilage defects in the athletic population presents a therapeutic challenge due to the high mechanical demands of athletic activity. Several articular cartilage repair techniques have been shown to successfully restore articular cartilage surfaces and allow athletes to return to high-impact sports. Postoperative rehabilitation is a critical component of the treatment process for athletic articular cartilage injury and should take into consideration the biology of the cartilage repair technique, cartilage defect characteristics, and each athlete's sport-specific demands to optimize functional outcome. Systematic, stepwise rehabilitation with criteria-based progression is recommended for an individualized rehabilitation of each athlete not only to achieve initial return to sport at the preinjury level but also to continue sports participation and reduce risk for reinjury or joint degeneration under the high mechanical demands of athletic activity.

Isokinetic muscle strength and knee function associated with double femoral pin fixation and fixation with interference screw in anterior cruciate ligament reconstruction

PURPOSE

Intensive scheduling in sports requires athletes to resume physical activity shortly after injury. The purpose of this study was to investigate early isokinetic muscle strength and knee function on bone-patellar tendon-bone (BPTB) ACL reconstruction with double femoral pin fixation or interference screw technique.

METHODS

A prospective study was conducted from 2008 to 2009, with 48 athletes who received femoral BPTB fixation with interference screw (n = 26) or double pin (n = 22). Clinical (IKDC objective score and hop test) and isokinetic muscle strength (peak torque (PT), PT/body weight and flexion/extension rate (F/E) in 60 and 240°/s) were analyzed at 6 months of follow-up.

RESULTS

Analysis at baseline showed no differences between groups before surgery related to age, gender, associated injury, Tegner or Lysholm score; thus showing that groups were similar. During follow-up, however, there were significant differences between the two groups in some of the isokinetic muscle strength: PT/BW 60°/s (Double Pin = 200% ± 13% vs. Interference Screw = 253% ± 16%*, *P = 0.01); F/E 60°/s (Double Pin = 89% ± 29%* vs. Interference Screw = 74% ± 12%, *P = 0.04). No statistical differences between groups were observed on IKDC objective score, hop test and complications.

CONCLUSION

The significant muscle strength outcome of the interference screw group found in this study gives initial evidence that this fixation technique is useful for athletes that may need accelerated rehabilitation. Early return to sports ability signaled by isokinetic muscle strength is of clinical relevance as it is one of the main goals for athletes' rehabilitation.

Scientific Evidence Base for Cartilage Injury and Repair in the Athlete

Soccer players and athletes in high-impact sports are frequently affected by knee injuries. Injuries to the anterior cruciate ligament and menisci are frequently observed in soccer players and may increase the risk of developing an articular cartilage lesion. In high-level athletes, the overall prevalence of knee articular cartilage lesions has been reported to be 36% to 38%. The treatment for athletic patients with articular cartilage lesions is often challenging because of the high demands placed on the repair tissue by impact sports. Cartilage defects in athletes can be treated with microfracture, osteochondral grafting, and autologous chondrocyte implantation. There is increasing scientific evidence for cartilage repair in athletes, with more extensive information available for microfracture and autologous chondrocyte implantation than for osteochondral grafting. The reported rates and times to return to sport at the preinjury level are variable in recreational players, with the best results seen in younger and high-level athletes. Better return to sport is consistently observed for all repair techniques with early cartilage repair. Besides minimizing sensorimotor deficits and addressing accompanying pathologies, the quality of the repair tissue may be a significant factor for the return to sport.

Return to preinjury sports participation following anterior cruciate ligament reconstruction: contributions of demographic, knee impairment, and self-report measures

STUDY DESIGN

Cross-sectional cohort.

OBJECTIVES

(1) To examine differences in clinical variables (demographics, knee impairments, and self-report measures) between those who return to preinjury level of sports participation and those who do not at 1 year following anterior cruciate ligament reconstruction, (2) to determine the factors most strongly associated with return-to-sport status in a multivariate model, and (3) to explore the discriminatory value of clinical variables associated with return to sport at 1 year postsurgery.

BACKGROUND

Demographic, physical impairment, and psychosocial factors individually prohibit return to preinjury levels of sports participation. However, it is unknown which combination of factors contributes to sports participation status.

METHODS

Ninety-four patients (60 men; mean age, 22.4 years) 1 year post-anterior cruciate ligament reconstruction were included. Clinical variables were collected and included demographics, knee impairment measures, and self-report questionnaire responses. Patients were divided into "yes return to sports" or "no return to sports" groups based on their answer to the question, "Have you returned to the same level of sports as before your injury?" Group differences in demographics, knee impairments, and self-report questionnaire responses were analyzed. Discriminant function analysis determined the strongest predictors of group classification. Receiver-operating-characteristic curves determined the discriminatory accuracy of the identified clinical variables.

RESULTS

Fifty-two of 94 patients (55%) reported yes return to sports. Patients reporting return to preinjury levels of sports participation were more likely to have had less knee joint effusion, fewer episodes of knee instability, lower knee pain intensity, higher quadriceps peak torque-body weight ratio, higher score on the International Knee Documentation Committee Subjective Knee Evaluation Form, and lower levels of kinesiophobia. Knee joint effusion, episodes of knee instability, and score on the International Knee Documentation Committee Subjective Knee Evaluation Form were identified as the factors most strongly associated with self-reported return-to-sport status. The highest positive likelihood ratio for the yes-return-to-sports group classification (14.54) was achieved when patients met all of the following criteria: no knee effusion, no episodes of instability, and International Knee Documentation Committee Subjective Knee Evaluation Form score greater than 93.

CONCLUSION

In multivariate analysis, the factors most strongly associated with return-to-sport status included only self-reported knee function, episodes of knee instability, and knee joint effusion.

Current concepts for anterior cruciate ligament reconstruction: a criterion-based rehabilitation progression

The management of patients after anterior cruciate ligament reconstruction should be evidence based. Since our original published guidelines in 1996, successful outcomes have been consistently achieved with the rehabilitation principles of early weight bearing, using a combination of weight-bearing and non-weight-bearing exercise focused on quadriceps and lower extremity strength, and meeting specific objective requirements for return to activity. As rehabilitative evidence and surgical technology and procedures have progressed, the original guidelines should be revisited to ensure that the most up-to-date evidence is guiding rehabilitative care. Emerging evidence on rehabilitative interventions and advancements in concomitant surgeries, including those addressing chondral and meniscal injuries, continues to grow and greatly affect the rehabilitative care of patients with anterior cruciate ligament reconstruction. The aim of this article is to update previously published rehabilitation guidelines, using the most recent research to reflect the most current evidence for management of patients after anterior cruciate ligament reconstruction. The focus will be on current concepts in rehabilitation interventions and modifications needed for concomitant surgery and pathology.

LEVEL OF EVIDENCE

Therapy, level 5.

Effects of sex on compensatory landing strategies upon return to sport after anterior cruciate ligament reconstruction

STUDY DESIGN

Controlled laboratory, cross-sectional, cohort design.

OBJECTIVE

To determine if a sex-specific pattern of lower limb asymmetries is present during a drop vertical jump (DVJ) maneuver at the time of return to sport after anterior cruciate ligament (ACL) reconstruction.

BACKGROUND

A high incidence of second ACL injury is reported after reconstruction; however, the underlying mechanisms of this injury are unclear. While asymmetrical dynamic loading patterns predictive of primary ACL injury in healthy female athletes were observed in female athletes 2 years after ACL reconstruction, it is unknown if similar asymmetries are present in male athletes after ACL reconstruction at the time of return to sport.

METHODS

A total of 98 participants were included in the study, 56 of whom had unilateral ACL reconstruction (35 female, 21 male) and had been released to return to unrestricted level 1 and 2 sports, and 42 of whom were uninjured, activity-matched control participants (29 female, 13 male). Lower extremity kinetic data were analyzed during a bilateral drop vertical jump maneuver from a 31-cm box. Peak vertical ground reaction force (VGRF) was calculated during the landing phase of the drop vertical jump and normalized to body weight (BW). A 2-by-2-by-2 analysis of variance was used to determine differences between side (involved versus uninvolved), group (ACL reconstruction versus control), and sex (female versus male) for the peak VGRF.

RESULTS

A significant side-by-group interaction for peak VGRF (P = .002) was observed during the landing phase of the drop vertical jump in the entire cohort. The involved limb of the ACL reconstructed group displayed significantly lower VGRF (mean ± SD, 1.77 ± 0.35 BW) than the uninvolved limb (2.2 ± 0.4 BW, P<.001) and both the preferred limb (2.0 ± 0.4 BW, P = .002) and nonpreferred limb (2.09 ± 0.42 BW, P<.001) in the control group. No effect of sex was noted.

CONCLUSION

After ACL reconstruction, both male and female participants at the time of return to sport demonstrated involved limb asymmetries in peak VGRF during landing from a bipedal task. These deficits, which persist at the time of return to sport, may increase the risk of future injury and indicate that rehabilitation after ACL reconstruction may require more targeted interventions to address involved limb biomechanical deficits in athletes of both sexes prior to return to sport participation.

Quadriceps strength and weight acceptance strategies continue to improve two years after anterior cruciate ligament reconstruction

The anterior cruciate ligament (ACL) is the most commonly-injured knee ligament during sporting activities. After injury, most individuals experience episodes of the knee giving way during daily activities (non-copers). Non-copers demonstrate asymmetrical quadriceps strength and movement patterns, which could have long-term deleterious effects on the integrity of the knee joint. The purpose of this study was to determine if non-copers resolve their strength and movement asymmetries within two years after surgery. 26 Non-copers were recruited to undergo pre-operative quadriceps strength testing and 3-dimensional gait analysis. Subjects underwent surgery to reconstruct the ligament followed by physical therapy focused on restoring normal range of motion, quadriceps strength, and function. Subjects returned for quadriceps strength testing and gait analysis six months and two years after surgery. Acutely after injury, quadriceps strength was asymmetric between limbs, but resolved six months after surgery. Asymmetric knee angles, knee moments, and knee and hip power profiles were also observed acutely after injury and persisted six months after surgery despite subjects achieving symmetrical quadriceps strength. Two years after surgery, quadriceps strength in the involved limb continued to improve and most kinematic and kinetic asymmetries resolved. These findings suggest that adequate quadriceps strength does not immediately resolve gait asymmetries in non-copers. They also suggest that non-copers have the capacity to improve their quadriceps strength and gait symmetry long after ACL reconstruction.

Utilization of modified NFL combine testing to identify functional deficits in athletes following ACL reconstruction

STUDY DESIGN

Case control.

OBJECTIVES

To use modified NFL Combine testing methodology to test for functional deficits in athletes following anterior cruciate ligament (ACL) reconstruction following return to sport.

BACKGROUND

There is a need to develop objective, performance-based, on-field assessment methods designed to identify potential lower extremity performance deficits and related impairments in this population.

METHODS

Eighteen patients (mean ± SD age, 16.9 ± 2.1 years; height, 170.0 ± 8.7 cm; body mass, 71.9 ± 21.8 kg) who returned to their sport within a year following ACL reconstruction (95% CI: 7.8 to 11.9 months from surgery) participated (ACLR group). These individuals were asked to bring 1 or 2 teammates to serve as control participants, who were matched for sex, sport, and age (n = 20; mean ± SD age, 16.9 ± 1.1 years; height, 169.7 ± 8.4 cm; body mass, 70.1 ± 20.7 kg). Functional performance was tested using the broad jump, vertical jump, modified long shuttle, modified pro shuttle, modified agility T-test, timed hop, triple hop, single hop, and crossover hop tests. A 1-way multivariate analysis of variance (MANOVA) was used to evaluate group differences for dependent performance variables.

RESULTS

The functional performance measurements of skills requiring bilateral involvement of both lower extremities showed no group differences between the ACLR and control groups (P>.05). An overall group difference (P = .006) was observed for the combined limb symmetry index (LSI) measures. However, the modified double-limb performance tasks (long shuttle, modified agility T-test, and pro shuttle) were not, independently, sufficiently sensitive to detect limb deficits in individuals with ACL reconstruction. Conversely, the LSI on the distance measures of the single-limb performance tasks all provided moderate to large effect sizes to differentiate between the ACLR and control groups, as the individuals who had ACL reconstruction demonstrated involved limb deficits on all measures (P<.05). Finally, the LSI for the timed hop test was not different between groups (P>.05).

CONCLUSIONS

These findings indicate that, while unilateral deficits are present in individuals following ACL reconstruction, they may not be evident during bipedal performance or during modified versions of double-limb performance activities. Isolation of the involved limb with unilateral hopping tasks should be used to identify deficits in performance.

Real-time assessment and neuromuscular training feedback techniques to prevent ACL injury in female athletes

Some athletes may be more susceptible to at-risk knee positions during sports activities, but the underlying causes are not clearly defined. This manuscripts synthesizes in vivo, in vitro and in-silica (computer simulated) data to delineate likely risk factors to the mechanism(s) of non-contact ACL injuries. From these identified risk factors, we will discuss newly developed real-time screening techniques that can be used in training sessions to identify modifiable risk factors. Techniques provided will target and correct altered mechanics which may reduce or eliminate risk factors and aid in the prevention of non-contact ACL injuries in high risk athletes.

The influence of graft choice on isokinetic muscle strength 4-24 months after anterior cruciate ligament reconstruction

PURPOSE

Regaining adequate strength of the quadriceps and hamstrings after anterior cruciate ligament (ACL) reconstruction is important for maximizing functional performance. However, the outcome of muscle strength after either BPTB or hamstrings autograft is unclear given the plethora of published studies that report post-operative muscle strength. The purpose of this study was to systematically compare the muscle strength of patients who have undergone ACL reconstruction using either Bone Patellar Tendon Bone (BPTB) or Hamstrings (HST) autograft.

METHODS

The databases of MEDLINE, Cinahal and EMBASE were systematically searched for articles that report muscle strength outcome following ACL reconstruction. The quality of the studies was evaluated and a meta-analysis of the muscle strength outcomes was conducted on reported data.

RESULTS

Fourteen studies were included in this systematic review: eight Randomized Control Studies (RCT) and six non-Randomized Control Studies (non-RCT). A meta-analysis was performed involving eight of the included studies (4 RCTs & 3 non-RCTs). At 60°/s and 180°/s, patients with BPTB graft showed a greater deficit in extensor muscle strength and lower deficit in flexor muscle strength compared with patients with HST.

CONCLUSION

This systematic review of Level III evidence showed that isokinetic muscle strength deficits following ACL reconstruction are associated with the location of the donor site. These deficits appear to be unresolved up to 2 years after ACL reconstruction.

LEVEL OF EVIDENCE

III.

A systematic review of sensorimotor function during adolescence: a developmental stage of increased motor awkwardness?

BACKGROUND

Although adolescent motor awkwardness and increased injury susceptibility have often been speculated and researched, studies regarding adolescent regressions in motor control have yielded inconsistent conclusions. Thus, the relationship between adolescent maturation and injury risk remains unclear. The purpose of this study was to systematically review the literature relative to two questions: (1) Which sensorimotor mechanisms are not fully mature by the time children reach adolescence? and (2) Is adolescence a period when children exhibit delays or regressions in sensorimotor mechanisms?

METHODS

Systematic searches for keywords were performed in February 2010 using PubMed MEDLINE (from 1966), CINAHL (from 1982) and SPORTDiscus (from 1985) databases. Articles were reviewed relative to predetermined criteria, and the methodological quality of each included study was assessed.

RESULTS

The search identified 2304 studies, of which 33 studies met the inclusion criteria. All 33 identified studies provided results associated with Question 1, 6 of which also yielded results pertaining to Question 2. The search results indicated that many aspects of sensorimotor function continue to mature throughout adolescence, and at least some children experience delays or regressions in at least some sensorimotor mechanisms. The results also exposed several significant weaknesses in our knowledge base.

CONCLUSION

The identified knowledge gaps are critical barriers because they hinder methods for identifying children at high risk and diminish the efficacy of targeted prevention programmes. Implications regarding research on adolescent injury risk are discussed and recommendations for future research such as improved methodological designs and integration of non-linear analyses are provided.

ACL injury and reconstruction: Clinical related in vivo biomechanics

Several researchers including our group have shown that knee joint biomechanics are impaired after anterior cruciate ligament (ACL) injury, in terms of kinematics and neuromuscular control. Current ACL reconstruction techniques do not seem to fully restore these adaptations. Our research has demonstrated that after ACL reconstruction, excessive tibial rotation is still present in high-demanding activities that involve both anterior and rotational loading of the knee. These findings seem to persist regardless of the autograft selection for the ACL reconstruction. Our results also suggest an impairment of neuromuscular control after ACL reconstruction, although muscle strength may have been reinstated. These abnormal biomechanical patterns may lead to loading of cartilage areas, which are not commonly loaded in the healthy knee and longitudinally can lead to osteoarthritis. Muscle imbalance can also influence patients' optimal sports performance exposing them to increased possibility of knee re-injury. In this review, our recommendations point towards further experimental work with in vivo and in vitro studies, in order to assist in the development of new surgical procedures that could possibly replicate more closely the natural ACL anatomy and prevent future knee pathology.

The relationship between functional levels and fear-avoidance beliefs following anterior cruciate ligament reconstruction

Background

The purpose of this study is to assess the relationship between functional levels in activities of daily living and sports and fear-avoidance beliefs in patients with a history of anterior cruciate ligament reconstruction (ACLR), after controlling for injury-related variables and physical impairment measures.

Patients and methods

Forty-eight subjects (34 men, 14 women; age 20.6 ± 1.2 years), at a mean of 31.7 ± 16.2 months following ACLR, participated in this study. Functional levels in activities of daily living and sports were assessed with the Knee Outcome Survey (KOS) Activities of Daily Living Scale (ADLS) and Sports Activity Scale (SAS). Fear-avoidance beliefs were assessed with the physical activity subscale of the fear-avoidance beliefs questionnaire (FABQ), which was adapted for use in patients with knee pathology. Injury-related variables included whether or not additional knee surgery was performed after the initial ACLR and the number of months from the most recent ACLR to participation in this study. Physical impairment measures included single-leg hop capabilities, quadriceps strength, and anterior knee joint laxity.

Results

Hierarchical linear regression analysis revealed that scores on the physical activity subscale of the FABQ contributed significantly to KOS ADLS and SAS scores after accounting for injury-related variables and physical impairment measures. The final regression model accounted for 61% of the variance in KOS ADLS and SAS scores (P < 0.001).

Conclusion

These results suggest that fear-avoidance beliefs following ACLR can potentially adversely influence functional levels in activities of daily living and sports.