Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study

Hand-held dynamometer identifies asymmetries in torque of the quadriceps muscle after anterior cruciate ligament reconstruction

PURPOSE

To verify the validity and diagnostic accuracy of the hand-held dynamometer (HHD) with the isokinetic dynamometer for evaluating the quadriceps strength of subjects who have undergone ACL reconstruction (ACLR).

METHODS

This validity and diagnostic accuracy study was conducted prospectively by examining 70 consecutive participants who had undergone ACLR at least 6 months previously. All participants performed strength evaluation of the quadriceps muscle using the HHD and isokinetic dynamometer.

RESULTS

The HHD presented high test-retest reliability [intraclass correlation coefficient (ICC) = 0.98], moderate to good validity with the isokinetic dynamometer when compared for the quadriceps strength (r = 0.62), 100% perfect specificity [LR + infinity, 95% confidence interval (CI) 81.4%-100%] to identify those with LSI > 10%, and a sensitivity of 63.4% (48.9%-76.3%).

CONCLUSION

The HHD is an instrument valid and reliable of low cost and easy handling compared to the isokinetic dynamometer to evaluate the quadriceps torque and the limb symmetry index after the ACLR with high diagnostic accuracy.

LEVEL OF EVIDENCE

I.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Functional electrical stimulation following anterior cruciate ligament reconstruction: a randomized controlled pilot study

Background

Inadequate quadriceps strength following anterior cruciate ligament reconstruction (ACLR) often results in alterations in gait pattern that are usually reported during loading response. Neuro-muscular electrical stimulation (NMES) is frequently used to overcome this quadriceps weakness. Despite the beneficial effects of NMES, persistent deficits in strength and gait are reported. The aim of this study was to investigate the feasibility of applying quadriceps functional electrical stimulation (FES) during walking in addition to standard rehabilitation, in the initial stage of ACLR rehabilitation.

Methods

Subjects were randomized to quadriceps FES synchronized with walking group (n = 10) or quadriceps NMES (duty cycle of 10 s on/10 s off) group (n = 13). Both interventions were performed for 10 min three days a week, in addition to a standard rehabilitation program. Assessments were performed up to 2 weeks before the ACLR (pre-ACLR), and 4 weeks postoperatively. Outcomes measured were gait speed, single limb stance gait symmetry, quadriceps isometric peak strength ratio (peak strength at 4 weeks/peak strength pre-ACLR) and peak strength inter-limb symmetry. Gait outcomes were also assessed 1-week post-surgery.

Results

Subjects in both groups regained pre-ACLR gait speed and symmetry after 4 weeks of rehabilitation, with no difference between groups. However, although pre-ACLR quadriceps peak strength was similar between groups (FES - 205 Nm, NMES − 225 Nm, p = 0.605), subjects in the FES group regained 82% of their pre-quadriceps strength compared to 47% in the NMES group (p = 0.02). In addition, after 4 weeks, the FES group had significantly better inter-limb strength symmetry 0.63 ± 0.15 vs. 0.39 ± 0.18 in the NMES group (p = 0.01).

Conclusions

Quadriceps FES combined with traditional rehabilitation is a feasible, early intervention treatment option, post-ACLR. Furthermore, at 4 weeks post-surgery, FES was more effective in recovering quadriceps muscle strength than was NMES. While spatiotemporal gait parameters did not differ between groups, kinetic and kinematic studies may be useful to further understand the effects of quadriceps FES post-ACLR. The promising results of this preliminary investigation suggest that such studies are warranted.

Trial registration

ISRCTN 02817399. First posted June 29, 2016.

Wearable inertial sensors and pressure MAT detect risk factors associated with ACL graft failure that are not possible with traditional return to sport assessments

Introduction

Anterior cruciate ligament reconstruction (ACLR) is associated with poor return to sport and high graft re-rupture rates. This study explored the use of a wearable inertial sensor (ViMove) that incorporates an accelerometer and gyroscope, and MatScan pressure sensing mat (TekScan, South Boston, Massachusetts, USA) to provide objective return-to-sport measures.

Methods

Three cohorts’ ACLR patients, non-athletic controls and elite athletes (Australian seven’s rugby Olympic Gold medallist). Patients performed biometric and functional tests (thigh circumference and triple hop) and the ViMove knee module (consisting of single and double leg squats, hops and box drops) for lower limb alignment assessment, concurrently with force plate.

Results

Elite athletes had less varus/valgus (VV) movement during ViMove exercises compared with the ACLR cohort, who in turn had less VV malalignment than controls. When analysing side-to-side differences, single leg squats and box drop were asymmetrical in the ACL group, with greater malalignment in the reconstructed leg (p<0.05). Subgroup analysis failed to differentiate who passed or failed current return to sport assessment. TekScan pressure plate detected differences in double leg landing and flight time while hopping not detected with ViMove, suggesting ACL patients compensate by offloading the reconstructed leg to improve coronal alignment during double leg activity.

Conclusion

The inertial sensor detected differences in motion for patients following ACLR, which are known to be associated with graft rupture and were not detected with functional return to sport testing. Coupling the device with data from a pressure plate provides a powerful assessment tool detecting alignment differences known to be associate with graft failure only previously detected in formal gait analysis.

Horizontal jumping biomechanics among elite male handball players with and without anterior cruciate ligament reconstruction. An inertial sensor unit-based study

OBJECTIVES

Anterior cruciate ligament (ACL) tears are one of the most devastating injuries that any handball player can suffer during landing and pivoting actions. The aim of this study was to analyze the horizontal jumping biomechanics among male elite handball players with or without previous ACLR.

DESIGN

Descriptive study.

SETTING

Spanish elite male handball players.

PARTICIPANTS

Twenty-six male participants (6 ACL-R and 20 uninjured controls) were recruited.

MAIN OUTCOME MEASURES

Two horizontal hopping tasks were evaluated using an inertial sensor unit (ISU)-based technology to assess jumping biomechanics through a direct mechanics-based approach.

RESULTS

Non-significant differences were found in relation to any of the biomechanical or performance related analyzed variables.

CONCLUSIONS

Previously ACL-R elite male handball players who have returned to the top level of sports participation do not seem to possess lasting biomechanical and/or performance deficits 6 years after the original surgical ligament repair.

Return to sports and re-rupture rate following anterior cruciate ligament reconstruction in amateur sportsman: long-term outcomes

BACKGROUND

The aim of this study was to retrospectively evaluate patient satisfaction, the return-to-sport rate and activity level at a long-term follow-up in a large cohort of amateur sportsmen who underwent primary anterior cruciate ligament (ACL) reconstruction.

METHODS

A total of 218 patients who underwent primary ACL reconstruction between 2004 and 2011, were successfully recontacted and retrospectively reviewed at an average follow-up of 10.5 years (range, 7 to 14 years). All surgeries were performed by one single surgeon. All of them underwent primary ACL reconstruction with autogenous hamstring tendon grafts. Assessment included Knee Osteoarthritis Outcome Score (KOOS) score, International Knee Documentation Committee (IKDC) Subjective Knee Form, Tegner activity level. Patients were also asked what kind of injury they sustained (either direct or indirect trauma), what kind of sport they were performing when they got injured, at what time they did return to sports and which sport they practised before and after surgery.

RESULTS

Fourteen patients underwent re-rupture. In 11 cases, this was due to a new trauma occurring at an average time of 22.9 (SD 23.8) months following primary surgery. In 3 cases rupture occurred during rehabilitation period. Mean postoperative KOOS score was 88.5 (SD 8.5), while mean IKDC subjective score was 87.5 (SD 10.9). At the time of follow-up, most patients (214 subjects, 98%) were participating in sport. 156 subjects returned to pre-injury level (71.6%).

CONCLUSIONS

The study reported long-term favourable subjective outcomes in amateur sportsman following ACL reconstruction, with a low re-rupture rate and a high percentage of subjects (93.6%) returning to sports participation 12 months after surgery. Most patients (71.6%) were able to return to their preprimary level of activity and sport. Younger age at the time of ACL reconstruction positively affected return to sports; however, younger patients were significantly more likely than older patients to undergo re-rupture.

Hamstring Muscle Activity After Primary Anterior Cruciate Ligament Reconstruction-A Protective Mechanism in Those Who Do Not Sustain a Secondary Injury? A Preliminary Study

BACKGROUND

Individuals who experience a subsequent ipsilateral anterior cruci (cruciate)ate ligament (ACL) reinjury may use hazardous muscle activation strategies after primary ACL reconstruction (ACLR). The purpose of this study was to compare electromyograms (EMGs) of the quadriceps, hamstrings, and gastrocnemius muscles during a dynamic hopping task among individuals with a single ACL injury (ACLx1), individuals who went on to have secondary ipsilateral ACL injury (ACLx2), and individuals who have never sustained an ACL injury (ACLx0).

HYPOTHESIS

We expected that individuals who went on to experience a secondary ACL injury would use less quadriceps muscle activity as compared with individuals who experienced a single ACL injury.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Fourteen individuals that were returned to play post-ACLR and 7 non-ACL-injured individuals participated. Individuals who had undergone an ACLR were placed into groups depending on whether they had experienced a secondary ipsilateral ACL reinjury postprimary ACLR. EMG data of the vastus lateralis, biceps femoris, and lateral gastrocnemius were measured during 2 phases of a single-leg dynamic hopping task: preactivity (100 ms prior to ground contact) and reactivity (250 ms post-ground contact). Processed EMG data were compared across groups using 1-way analyses of variance, with post hoc independent t tests where appropriate (P ≤ 0.05).

RESULTS

At preactivity, ACLx1 (0.48% ± 0.2%max) was found to use significantly more hamstring activity than ACLx2 (0.20% ± 0.1%max, P = 0.018), but not than ACLx0 (0.38% ± 0.1%max, P > 0.05). At reactivity, both ACL groups were found to use less quadriceps activity than ACLx0 (ACLx1: 0.38% ± 0.1%max, P = 0.016; ACLx2: 0.40% ± 0.1%max, P = 0.033; ACLx0: 0.58% ± 0.1%max), but not than each other (P > 0.05).

CONCLUSION

Quadriceps muscle activity during landing was diminished in all ACL participants as compared with participants who had never sustained an ACL injury. Individuals who did not experience a secondary ipsilateral ACL reinjury (ACLx1) used greater levels of hamstring activity prior to landing.

CLINICAL RELEVANCE

The higher hamstring activity in patients who did not experience a secondary injury may be interpreted as a protective mechanism that is used to dynamically stabilize the reconstructed limb.

Time before return to play for the most common injuries in professional football: a 16-year follow-up of the UEFA Elite Club Injury Study

Objectives

The objective was to describe the typical duration of absence following the most common injury diagnoses in professional football.

Methods

Injuries were registered by medical staff members of football clubs participating in the Union of European Football Association Elite Club Injury Study. Duration of absence due to an injury was defined by the number of days that passed between the date of the injury occurrence and the date when the medical team allowed the player to return to full participation. In total, 22 942 injuries registered during 494 team-seasons were included in the study.

Results

The 31 most common injury diagnoses constituted a total of 78 % of all reported injuries. Most of these injuries were either mild (leading to a median absence of 7 days or less, 6440 cases = 42%) or moderate (median absence: 7–28 days, 56% = 8518 cases) while only few (2% = 311 cases) were severe (median absence of >28 days). The mean duration of absence from training and competition was significantly different (p < 0.05) between index injuries and re-injuries for six diagnoses (Achilles tendon pain, calf muscle injury, groin adductor pain, hamstring muscle injuries and quadriceps muscle injury) with longer absence following re-injuries for all six diagnoses

Conclusions

The majority of all time loss due to injuries in professional football stems from injuries with an individual absence of up to 4 weeks. This article can provide guidelines for expected time away from training and competition for the most common injury types as well as for its realistic range.

How should clinicians rehabilitate patients after ACL reconstruction? A systematic review of clinical practice guidelines (CPGs) with a focus on quality appraisal (AGREE II)

OBJECTIVES

To summarise recommendations and appraise the quality of international clinical practice guidelines (CPGs) for rehabilitation after ACL reconstruction.

DESIGN

Systematic review of CPGs (PROSPERO number: CRD42017020407).

DATA SOURCES

Pubmed, EMBASE, Cochrane, SPORTDiscus, PEDro and grey literature databases were searched up to 30 September 2018.

ELIGIBILITY CRITERIA

English-language CPGs on rehabilitation following ACL reconstruction that used systematic search of evidence to formulate recommendations.

METHODS

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to report the systematic review. Two appraisers used the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument to report comprehensiveness, consistency and quality of CPGs. We summarised recommendations for rehabilitation after ACL reconstruction.

RESULTS

Six CPGs with an overall median AGREE II total score of 130 points (out of 168) and median overall quality of 63% were included. One CPG had an overall score below the 50% (poor quality score) and two CPGs scored above 80% (higher quality score). The lowest domain score was 'applicability' (can clinicians implement this in practice?) (29%) and the highest 'scope and purpose' (78%) and 'clarity of presentation' (75%). CPGs recommended immediate knee mobilisation and strength/neuromuscular training. Early full weight-bearing exercises, early open and closed kinetic-chain exercises, cryotherapy and neuromuscular electrostimulation may be used according individual circumstances. The CPGs recommend against continuous passive motion and functional bracing.

CONCLUSION

The quality of the CPGs in ACL postoperative rehabilitation was good, but all CPGs showed poor applicability. Immediate knee mobilisation and strength/neuromuscular training should be used. Continuous passive motion and functional bracing should be eschewed.

Strength and Function Across Maturational Levels in Young Athletes at the Time of Return to Sport After ACL Reconstruction

BACKGROUND

The impact of maturation on lower extremity strength and function after anterior cruciate ligament reconstruction (ACLR) may help guide future studies of age-specific rehabilitation.

HYPOTHESIS

Pediatric ACLR patients would demonstrate higher thigh strength symmetry and knee-related function at return to sport (RTS) compared with adolescent and young adult participants who underwent traditional ACLR.

STUDY DESIGN

Prospective cohort study.

LEVEL OF EVIDENCE

Level 2.

METHODS

A total of 144 young athletes at the time of RTS clearance post-ACLR were classified into 3 maturational groups (pediatric, n = 16 with physeal-sparing ACLR [mean age = 12.3 years; range = 9.2-14.6 years]; adolescent, n = 113 [mean age = 16.5 years; range = 14.1-19.8 years]; young adult, n = 15 [mean age = 22.0 years; range = 20.5-24.9 years]). Quadriceps and hamstring strength were measured using an electromechanical dynamometer. Knee-related function was measured using the International Knee Documentation Committee (IKDC) subjective form and single-leg hop tests. The Limb symmetry Index (LSI) was used in calculations for hop and strength tests. Group differences were compared with Kruskal-Wallis tests and Mann-Whitney U post hoc tests. Proportions of participants meeting literature-recommended RTS criterion cutoffs were compared among the groups using chi-square tests.

RESULTS

The pediatric group demonstrated higher quadriceps LSI (P = 0.01), IKDC scores (P < 0.01), single-hop LSI (P < 0.01), and crossover-hop LSI (P = 0.02) compared with the young adult group. In addition, the pediatric group demonstrated higher IKDC scores (P < 0.01) and single-hop LSI (P = 0.02) compared with the adolescent group. The adolescent group demonstrated higher IKDC scores (P < 0.01), single-hop LSI (P = 0.02), and crossover-hop LSI (P = 0.03) compared with the young adult group. The proportions of participants meeting all RTS criterion cutoffs were highest in the pediatric group and lowest in the young adult group (P = 0.03).

CONCLUSION

Young athletes at RTS clearance after pediatric ACLR demonstrated higher quadriceps strength symmetry and knee-related function than adolescents and young adults after traditional ACLR.

CLINICAL RELEVANCE

These findings demonstrate the need for further study regarding the impact of these group differences on longitudinal outcomes after ACLR, including successful RTS and risk of second ACL injury.

The validity and reliability of the Vail Sport Test™ as a measure of performance following anterior cruciate ligament reconstruction

OBJECTIVES

To determine the validity and inter-session reliability of the Vail Sport Test™.

DESIGN

Cohort study-exploratory methodological research design.

SETTING

Clinical Research Laboratory.

PARTICIPANTS

Forty-eight participants who underwent ACL-R.

MAIN OUTCOME MEASURE

Participants performance on the Vail Sport Test™ was graded by an experienced rater in real-time, and simultaneously recorded by a three-dimensional (3D) motion capture system. Construct validity was assessed using the reference standards of the camera system and the IKDC short form. To determine the between-day reliability, a subset of participants returned to repeat the test.

RESULTS

There were no significant difference between the scores collected in real-time and from the kinematic data on the involved limb (p = 0.222). There was a significant difference for the uninvolved limb (p = 0.015). There was no significant difference between the scores collected in real time and those of the IKDC (p = 0.885). Good inter-session reliability (ICC = 0.787) was found for the involved limb.

CONCLUSION

The results of this study showed good reliability and partially support the validity of the Vail Sport Test as a measure of readiness to return to play.

The use of allograft tendons in primary ACL reconstruction

PURPOSE

Graft choice in primary anterior cruciate ligament (ACL) reconstruction remains controversial. The use of allograft has risen exponentially in recent years with the attraction of absent donor site morbidity, reduced surgical time and reliable graft size. However, the published evidence examining their clinical effectiveness over autograft tendons has been unclear. The aim of this paper is to provide a current review of the clinical evidence available to help guide surgeons through the decision-making process for the use of allografts in primary ACL reconstruction.

METHODS

The literature in relation to allograft healing, storage, sterilisation, differences in surgical technique and rehabilitation have been reviewed in addition to recent comparative studies and all clinical systematic reviews and meta-analyses.

RESULTS

Early reviews have indicated a higher risk of failure with allografts due to association with irradiation for sterilisation and where rehabilitation programs and post-operative loading may ignore the slower incorporation of allografts. More recent analysis indicates a similar low failure rate for allograft and autograft methods of reconstruction when using non-irradiated allografts that have not undergone chemically processing and where rehabilitation has been slower. However, inferior outcomes with allografts have been reported in young (< 25 years) highly active patients, and also when irradiated or chemically processed grafts are used.

CONCLUSION

When considering use of allografts in primary ACL reconstruction, use of irradiation, chemical processing and rehabilitation programs suited to autograft are important negative factors. Allografts, when used for primary ACL reconstruction, should be fresh frozen and non-irradiated. Quantification of the risk of use of allograft in the young requires further evaluation.

LEVELS OF EVIDENCE

III.

How Is Psychological Outcome Related to Knee Function and Return to Sport Among Adolescent Athletes After Anterior Cruciate Ligament Reconstruction?

BACKGROUND

Adult patients who succeed in returning to their preinjury levels of sport after anterior cruciate ligament (ACL) reconstruction have been characterized by a more positive psychological response. It is not known whether this relationship is valid for adolescent athletes.

PURPOSE

To investigate psychological readiness to return to sport, knee-related self-efficacy, and motivation among adolescent (15-20 years old) and adult (21-30 years old) athletes after ACL reconstruction. A further aim was to compare athletes (15-30 years old) who had recovered their muscle function and returned to sport with athletes who had not.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were extracted from a rehabilitation-specific register 8 and 12 months after ACL reconstruction. Athletes previously involved in knee-strenuous sport who had undergone primary ACL reconstruction were included. Data comprised psychological patient-reported outcomes and results from 5 tests of muscle function. Comparisons were performed between age groups, between athletes who had and had not recovered their muscle function, and between patients who had returned to sport and not.

RESULTS

In all, 384 (50% females) and 271 athletes (52% females) were included at the 8- and 12- month follow-ups, respectively. Enhanced self-efficacy was reported at both follow-ups by adolescents and by athletes who had recovered their muscle function. Athletes who had recovered their muscle function reported higher ( P = .0007) motivation to achieve their goals. Subgroup analyses on patient sex revealed findings similar to those in the main analyses for females but not for males. Moreover, adolescent and adult athletes who had returned to sport reported significantly higher levels on the Knee Self-Efficacy Scale and the ACL-Return to Sport After Injury scale at both follow-ups.

CONCLUSION

Adolescent athletes, especially females, perceived enhanced self-efficacy, had a higher return-to-sport rate, and were more motivated to reach their goals after ACL reconstruction compared with adults. Regardless of age, athletes who had returned to sport and athletes with more symmetrical muscle function had a stronger psychological profile.

Comparison of Short-term Biodex Results After Anatomic Anterior Cruciate Ligament Reconstruction Among 3 Autografts

Background:

An individualized approach to anterior cruciate ligament reconstruction (ACLR) typically includes criteria-based postoperative rehabilitation. However, recent literature has suggested residual quadriceps weakness up to 12 months after ACLR, especially with a quadriceps tendon (QT) autograft.

Hypothesis:

The QT would have poorer quadriceps strength symmetry at 5 to 8 months compared with the hamstring tendon (HS) and patellar tendon (BPTB), but there would be no significant difference at 9 to 15 months among all 3 groups.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients who underwent anatomic primary ACLR with an autograft were reviewed retrospectively. Isometric quadriceps and hamstring strength measurements were obtained clinically at 5 to 8 months and 9 to 15 months postoperatively. Return-to-running and return-to-play criteria included greater than 80% and 90% quadriceps strength symmetry, respectively.

Results:

A total of 73 patients with 5- to 8-month follow-up were identified, and 52 patients had 9- to 15-month data. The QT group had a significantly lower quadriceps index at 5 to 8 months (69.5 ± 17.4) compared with the BPTB (82.8 ± 14.6; P = .014) and the HS (86.0 ± 18.6; P = .001) groups. More patients with an BPTB autograft met criteria for return to running and return to play (60% and 47%, respectively) compared with the QT group (26% and 13%, respectively) at 5 to 8 months. Given the sample sizes available, we observed no significant difference in the quadriceps index and return-to-play and return-to-running criteria at 9 to 15 months among those undergoing ACLR with a QT, BPTB, or HS graft.

Conclusion:

Patients undergoing ACLR with a QT graft demonstrated clinically meaningful quadriceps asymmetry at 5 to 8 months and 9 to 15 months postoperatively. Additionally, fewer patients in the QT group met criteria for return to play and running at 5 to 8 months than the BPTB and HS groups. These data suggest that a longer time to return to play and specific rehabilitation protocols that emphasize quadriceps strengthening may be necessary because of residual quadriceps weakness after ACLR with a QT graft.

When Is It Safe to Return to Sport After ACL Reconstruction? Reviewing the Criteria

CONTEXT

There is an ever-increasing trend toward sports, fitness, and recreation activities, so the incidence of anterior cruciate ligament sports injuries has increased. Perhaps the greatest challenge for sports clinicians is to return the injured athlete back to his/her original sport at an even greater level of functional ability than preinjury. For this, rigorous and well-researched criteria are needed.

EVIDENCE ACQUISITION

Using medical subject headings and free-text words, an electronic search was conducted up to October 2018. Subject-specific search was based on the terms return to play and return to sport in combination with guidelines, criteria, and anterior cruciate ligament reconstruction.

STUDY DESIGN

Descriptive review.

LEVEL OF EVIDENCE

Level 2.

RESULTS

Five principal criteria were found, including psychological factors, performance/functional tests, strength tests, time, and modifiable and nonmodifiable risk factors.

CONCLUSION

The psychological readiness of the player is a major factor in successful safe return to sport (SRTS) decision making. Although strength, performance, and functional tests presently form the mainstay of SRTS criteria, there exists very little scientific evidence for their validity. More protection should be provided to athletes with known risk factors. Movement quality is important, if not more important than the quantifiable measures. As a result of the significantly high rerupture rate in young individuals, delayed SRTS should be considered preferably beyond 9 months postsurgery.

Anterior Cruciate Ligament Reconstruction Rehabilitation Clinical Practice Patterns: A Survey of the PRiSM Society

Background:

Recovery after anterior cruciate ligament (ACL) reconstruction (ACLR) requires extensive postoperative rehabilitation. Although no ideal rehabilitation procedure exists, most experts recommend a fusion of time and strength and functional measures to guide decision making for activity progression during rehabilitation. This process is often directed by surgeon protocols; however, the adoption of contemporary rehabilitation recommendations among surgeons is unknown.

Purpose:

To understand the current landscape of surgeon practice as it relates to ACLR rehabilitation recommendations in adolescent athletes.

Study Design:

Cross-sectional study.

Methods:

An online survey was distributed among members of the Pediatric Research in Sports Medicine (PRiSM) Society in January 2017. The survey was designed to identify clinical practice patterns during 3 key transitional points of rehabilitation after ACLR: progression to jogging, modified sports activity, and unrestricted return to sports.

Results:

Responses from 60 orthopaedic surgeons were analyzed. While 80% of surgeons agreed upon initiating jogging within a 1-month range (3-4 months postoperatively), similar levels of agreement were only captured when including a wider 4-month (4-8 months) and 6-month range (6-12 months) for modified sports activity and unrestricted return to sports, respectively. All respondents (100%) reported using knee strength as a determinant to progress to modified sports activity; however, the mode of testing varied, with most using manual muscle testing (60%), followed by isokinetic (28%) or isometric (12%) testing. Most surgeons (68%) reported using some form of functional testing to return to modified sports activity, but the mode of testing and required progression criteria varied considerably among all reported testing procedures. The use of patient-reported outcome measures was limited to 20% of the sample, and no respondents reported using fear or self-efficacy questionnaires. Upon completion of rehabilitation, 73% recommended injury prevention programs, and 50% recommended the use of a functional ACL brace.

Conclusion:

Rehabilitation progression practices in adolescent athletes are variable and become more inconsistent as the time from surgery increases. While the majority of the sample considered strength and functional testing important, the mode of testing and criteria thresholds for activity advancement varied considerably.

Back to Normal Symmetry? Biomechanical Variables Remain More Asymmetrical Than Normal During Jump and Change-of-Direction Testing 9 Months After Anterior Cruciate Ligament Reconstruction

BACKGROUND

After anterior cruciate ligament reconstruction (ACLR), athletes have demonstrated performance asymmetries as compared with healthy cohorts, but little research has investigated if biomechanical asymmetries are also different during jump and change-of-direction (CoD) tasks between groups.

PURPOSE

To identify if differences in magnitude of asymmetry of biomechanical and performance variables exist between these groups.

STUDY DESIGN

Controlled laboratory study.

METHODS

Analysis was conducted between 156 male patients 9 months after surgery and 62 healthy participants. Three-dimensional motion capture and analysis were carried out on a double-legged drop jump, a single-legged drop jump, a single-legged hop for distance, and planned and unplanned CoD. Asymmetry between limbs was calculated for each variable with root mean square difference between limbs. Statistical parametric mapping was used to identify the between-group differences in magnitude of asymmetry of performance and biomechanical variables.

RESULTS

There were differences in asymmetry of biomechanical variables across all jump and CoD tests, with greater asymmetries in the ACLR group. The majority of differences between groups were in the sagittal and frontal planes, with more differences found in the jump than CoD tests. The single-legged drop jump demonstrated large differences in performance asymmetry (effect size, 0.94) with small differences for both CoD tests (0.4) and none for the single-legged hop for distance.

CONCLUSION

This study demonstrated greater asymmetry of biomechanical variables 9 months after ACLR as compared with healthy participants across all tests, suggesting insufficient rehabilitation.

CLINICAL RELEVANCE

This study highlights the importance of including biomechanical as well as performance variables when assessing rehabilitation status after ACLR.

REGISTRATION

NCT02771548 ( ClinicalTrials.gov identifier).

Strength Training Effects on Muscular Regeneration after ACL Reconstruction

PURPOSE

Protracted quadriceps muscle atrophy is observed after anterior cruciate ligament reconstruction (ACL-R). The aim of this study was to assess if quadriceps strength training with eccentric overload (CON/ECC) is more efficient to induce muscle regeneration after ACL-R than conventional concentric/eccentric (CON/ECC) strength training.

METHODS

Biopsies from the vastus lateralis muscle were obtained from 37 recreational athletes after 12 wk of regular rehabilitation after ACL-R and again after 12 wk with twice a week of either conventional CON/ECC (n = 16) or CON/ECC (n = 21) one-legged supervised leg-press training. Immunohistochemical analyses were used to determine satellite cell (SC) number (Pax7); activated SC number (Pax7/MyoD); fibers expressing myosin heavy-chain (MHC) I and II, MHC neonatal, and fiber cross-sectional area. Magnetic resonance imaging was performed to measure quadriceps cross-sectional area and isokinetic testing for the measurement of quadriceps strength.

RESULTS

CON/ECC induced a significantly (P = 0.002) greater increase in quadriceps cross-sectional area than did CON/ECC. There also was a significant increase in the fiber cross-sectional areas of all fiber types and in quadriceps strength, but without significant difference between training groups. Only CON/ECC training led to a significant (P < 0.05) increase in percent type I fibers. After training, the number of MHC I/MHCneo fibers was significantly (P < 0.05) greater in the CON/ECC than after in the CON/ECC group. The proportion of hybrid fibers tended to decrease in both groups; percent type II fibers, SC number, and activated SC number remained unchanged.

CONCLUSIONS

CON/ECC leads to significantly greater muscle hypertrophy compared with CON/ECC, but without the hypothesized enhancing effect on SC activation. At the same time, CON/ECC+ induces a less favorable slower muscle phenotype for strong and fast movements.

A pragmatic approach to prevent post-traumatic osteoarthritis after sport or exercise-related joint injury

Lower extremity musculoskeletal injuries are common in sport and exercise, and associated with increased risk of obesity and post-traumatic osteoarthritis (PTOA). Unlike other forms of osteoarthritis, PTOA is common at a younger age and associated with more rapid progression, which may impact career choices, long-term general health and reduce quality of life. Individuals who suffer an activity-related joint injury and present with abnormal joint morphology, elevated adiposity, weak musculature, or become physically inactive are at increased risk of PTOA. Insufficient exercise therapy or incomplete rehabilitation, premature return-to-sport and re-injury, unrealistic expectations, or poor nutrition may further elevate this risk. Delay in surgical interventions in lieu of exercise therapy to optimize muscle strength and neuromuscular control while addressing fear of movement to guarantee resumption of physical activity, completeness of rehabilitation before return-to-sport, education that promotes realistic expectations and self-management, and nutritional counseling are the best approaches for delaying or preventing PTOA.

Knee Function, Strength, and Resumption of Preinjury Sports Participation in Young Athletes Following Anterior Cruciate Ligament Reconstruction

BACKGROUND

Following anterior cruciate ligament reconstruction (ACLR), young athletes demonstrate deficits in knee function and strength whose association with successful return to preinjury sports participation is not well understood.

OBJECTIVES

To examine differences in knee function and strength at the time of return-to-sport clearance between young athletes who successfully resumed preinjury sports participation, those who did not resume preinjury sports participation, and those who sustained a second anterior cruciate ligament (ACL) injury by 1 year following return-to-sport clearance.

METHODS

This prospective cohort study collected data in 124 young athletes (mean ± SD age, 17.1 ± 2.4 years) at the time of return-to-sport clearance post ACLR. Measures included the Knee injury and Osteoarthritis Outcome Score (KOOS), single-leg hop tests, isokinetic quadriceps and hamstring strength, and limb symmetry during hop tests and strength tests. Participants were allocated to 3 groups: resumed preinjury sports participation (Tegner score), did not resume preinjury sports participation, or sustained a second ACL injury. Group differences were compared using Kruskal-Wallis tests and Mann-Whitney U post hoc tests.

RESULTS

Seventy (56%) participants successfully resumed preinjury sports participation and 26 (21%) sustained a second ACL injury by 1 year post return-to-sport clearance. Participants who successfully resumed preinjury sports participation demonstrated greater absolute performance at return-to-sport clearance in the involved and uninvolved limbs on the triple hop (P = .007 and P = .004, respectively) and the crossover hop (P = .033 and P = .037, respectively), and in the involved limb on the single hop (P = .043), compared to those who did not (n = 28). Participants who sustained a second ACL injury demonstrated greater absolute performance at return-to-sport clearance in the involved and uninvolved limbs on the triple hop (P = .034 and P = .027, respectively) compared to those who did not resume preinjury sports participation. There were no group differences between those who successfully resumed preinjury levels of sports participation and those who sustained a second ACL injury.

CONCLUSION

Following ACLR, the small proportion of young athletes who successfully resumed preinjury levels of sports participation 1 year after return to sport demonstrated greater absolute functional performance at the time of return-to-sport clearance. No differences were identified between those who successfully resumed preinjury sports participation and those who sustained a second ACL injury. Measures of limb symmetry did not differ among any of the groups.

LEVEL OF EVIDENCE

Prognosis, level 2b. J Orthop Sports Phys Ther 2019;49(3):145-153. doi:10.2519/jospt.2019.8624.

Adductor Canal Nerve Versus Femoral Nerve Blockade for Pain Control and Quadriceps Function Following Anterior Cruciate Ligament Reconstruction With Patellar Tendon Autograft: A Prospective Randomized Trial

PURPOSE

To compare femoral nerve blockade (FNB) versus adductor canal nerve blockade (ACB) for postoperative pain control and quadriceps muscle function in patients undergoing anterior cruciate ligament (ACL) reconstruction with patellar tendon autograft.

METHODS

A randomized therapeutic trial of 90 patients undergoing ACL reconstruction with patellar tendon autograft was conducted comparing ACB versus FNB at 24 hours, 2 and 4 weeks, and 6 months postsurgery. Early outcome measures included average pain score and morphine equivalent units (milligrams) consumed, quadriceps surface electromyography, straight leg raise, and ability to ambulate without assistive devices. The 6-month outcome measures included knee range of motion (ROM), isokinetic knee extension peak torque, single-leg squat, and single-leg hop performance. Complications were recorded throughout the study for the development of anterior knee pain, knee extension ROM loss, deep vein thrombosis, and graft failure. Mixed-model analysis of variance and Mann-Whitney U tests were performed using an alpha of .05.

RESULTS

Quadriceps surface electromyography deficits were higher for FNB at 24 hours (P < .001) and 2 weeks (P < .001) when compared with the ACB group. There were no between-groups difference for subjective pain (P = .793) or morphine consumption (P = .358) within the first 24 hours of surgery. A higher percentage of patients in the ACB group met the full ambulation criteria at 4 weeks compared with the FNB group (100% vs 84.2%, P < .001). No between-group differences were observed at 6 months; however, the rate of knee extension ROM loss was higher for the FNB group versus the ACB group (21.1% vs 5.0%, P = .026), respectively.

CONCLUSIONS

ACB was as effective as FNB at providing pain control while eliciting fewer quadriceps muscle activation deficits and fewer postoperative complications. Based on previous evidence and the results of this study, we recommend the use of ACB over FNB for the analgesic management of patients undergoing ACL reconstruction with patellar tendon autograft.

LEVEL OF EVIDENCE

Level I, prospective randomized controlled trial.

Communication quality between the medical team and the head coach/manager is associated with injury burden and player availability in elite football clubs

OBJECTIVES

We investigated medical staff interpretations and descriptions of internal communication quality in elite football teams to determine whether internal communication was correlated with injuries and/or player availability at training and matches.

METHODS

Medical staff from 36 elite football clubs across 17 European countries produced 77 reports at four postseason meetings to provide their perceptions of internal communications in their teams. They also recorded data on individual players' exposure to football and time-loss injuries.

RESULTS

The injury burden and incidence of severe injuries were significantly higher in teams with low quality of communication between the head coach/manager and the medical team (scores of 1-2 on a 5-point Likert scale) compared with teams with moderate or high-quality scores (scores of 3-5; p=0.008 for both). Teams with low scores had 4%-5% lower training attendance (76% vs 83%, p=0.001) and less availability at matches (82% vs 88%, p=0.004) compared with teams with moderate or high communication quality scores.

CONCLUSIONS

The quality of internal communication within a team was correlated with injury rates, training attendance and match availability.

Demographic and surgical factors affect quadriceps strength after ACL reconstruction

PURPOSE

To investigate the effects of graft source, time since surgery, age, and sex on unilateral and symmetry-based measures of knee extension strength among individuals with ACL reconstruction (ACLR).

METHODS

Three hundred and eight individuals aged 13-40 years old with primary, unilateral ACLR in the last 60 months were enrolled in this multi-site clinical measurement study. Participants completed bilateral knee extension maximal voluntary isometric contraction (MVIC) torque assessments which were normalized to body mass (Nm/kg) and limb symmetry indices (LSI) were calculated. The effects of graft source (patellar tendon autograft; hamstring tendon autograft), time since surgery (≤ 12 months; >12 mo.), age (≤ 18 years; >18 years), and sex were evaluated using separate ANCOVAs.

RESULTS

A significant interaction was present between time since surgery and graft source for LSI (P = 0.01) as participants with patellar tendon autografts ≤ 12 months post-ACLR experienced the greatest asymmetry (LSI = 69.2 ± 24.5%). Significant interactions were present between time since surgery and sex for involved limb (P = 0.01) and uninvolved limb MVIC torque (P = 0.05) with females ≤ 12 months post-ACLR being weakest (involved MVIC = 1.81 ± 0.70 N m/kg; uninvolved MVIC = 2.40 ± 0.68 N m/kg). Participants ≤ 18-year-old displayed weaker involved limb (P < 0.001) and contralateral limb (P < 0.001) MVIC torque as compared to participants > 18-year-old during the first year after ACLR.

CONCLUSIONS

Graft source, sex, age, and time since surgery effect quadriceps strength and symmetry after ACLR. Surgical and demographic factors should be considered when developing treatment approaches to optimize quadriceps function prior to re-integration into pre-injury levels of physical activity.

LEVEL OF EVIDENCE

IV.

Contact times of change-of-direction manoeuvres are influenced by age and the type of sports: a novel protocol using the SpeedCourt® system

PURPOSE

Side-to-side asymmetry in side-cutting manoeuvres is a known risk factor for severe knee injury. Potential leg asymmetry during ground contact times of different change-of-direction manoeuvres was evaluated in athletes by means of the recently developed SpeedCourt^® system. The hypotheses were that ground contact times and the limb symmetry index are affected by age and the type of sports.

METHODS

One-hundred and sixty-five athletes (149 men, 16 women, age 16.5 ± 5.1) of popular team sports such as football, team handball and baseball were assessed by means of three different tests [side-hop, lateral change-of-direction (COD) and diagonal COD] using the SpeedCourt^® system. Analysis included the factors age, sex, type of sports, ground contact time, leg symmetry index and limb dominance.

RESULTS

During lateral but not diagonal COD tests, football players had shorter contact times than players of team handball (p = 0.026) and baseball (p = 0.015) of the same age group. The side-hop tests yielded differences in the leg symmetry index between players < 16 years and players > 16 years (p < 0.01). Mean ground contact time differed in each of the side-hop, lateral COD and diagonal COD tests (143.5 ± 20.0 vs. 256.2 ± 66.1 vs. 320.4 ± 55.0). Contact times and test durations of side-hop, lateral COD and diagonal COD tests were shorter for older players (p < 0.01).

CONCLUSIONS

Ground contact times of side-hop and change-of-direction manoeuvres are influenced by age, the type of sports and limb dominance. Such information is fundamental for future sports medicine research and needs to be considered in pre-season screening or when used as a criterion for return-to-competition of players with previous severe knee injury. Assessment of change-of-direction manoeuvres should be included in future return-to-competition test batteries.

LEVEL OF EVIDENCE

III.

Knee strength, hop performance and self-efficacy at 4 months are associated with symmetrical knee muscle function in young athletes 1 year after an anterior cruciate ligament reconstruction

Objectives

We investigated whether patient demographics, 4-month patient-reported outcomes (PRO) and muscle function predicted young athletes regaining symmetrical muscle function in five tests of muscle function 1 year after ACL reconstruction.

Methods

We extracted data on patient demographics, PROs and the results of five tests of muscle function from a rehabilitation-specific register. Athletes were 15–30 years of age, involved in knee-strenuous sport and had undergone a primary ACL reconstruction. The primary outcome was achieving a Limb Symmetry Index of ≥90% for the battery of tests 1 year after ACL reconstruction. Patient demographics, muscle-function data and results for PROs at the 4-month follow-up were analysed.

Results

In all, 237 athletes (59% female; mean age 22±4 years) were included in the study. One year after ACL reconstruction, 26% (62/237) of the included athletes had achieved symmetrical muscle function. Univariable analysis showed that symmetrical muscle function was associated with present self-efficacy, OR 1.28 (95% CI 1.04 to 1.58, p=0.011), knee-extension strength, OR 1.73 (95% CI 1.28 to 2.34), knee-flexion strength, OR 1.39 (95% CI 1.07 to 1.81), vertical hop, OR 1.77 (95% CI 1.27 to 2.45), single-leg hop for distance, OR 1.98 (95% CI 1.24 to 3.17) and side hop, OR 1.64 (95% CI 1.15 to 2.33).

Conclusion

Symmetrical knee-extension and knee-flexion strength, a more symmetrical hop performance and higher present self-efficacy at an early stage all increased the odds of achieving symmetrical muscle function in young athletes 1 year after ACL reconstruction.

Evidence-based recommendations for the management of anterior cruciate ligament (ACL) rupture

Anterior cruciate ligament (ACL) rupture occurs most commonly in young and active individuals and can have negative long-term physical and psychological impacts. The diagnosis is made with a combination of patient's history, clinical examination, and, if appropriate, magnetic resonance imaging. The objectives of management are to restore knee function, address psychological barriers to activity participation, prevent further injury and osteoarthritis, and optimize long-term quality of life. The three main treatment options for ACL rupture are (1) rehabilitation as first-line treatment (followed by ACL reconstruction (ACLR) in patients, who develop functional instability), (2) ACLR and post-operative rehabilitation as the first-line treatment, and (3) pre-operative rehabilitation followed by ACLR and post-operative rehabilitation. We provide practical recommendations for informing and discussing management options with patients, and describe patient-related factors associated with a worse ACL-rupture outcome. Finally, we define evidence-based rehabilitation and present phase-specific rehabilitation recommendations and criteria to inform return to sport decisions.

Corticospinal excitability can discriminate quadriceps strength indicative of knee function after ACL-reconstruction

PURPOSE

To investigate relationships between quadriceps strength and neural activity, and to establish a clinical threshold of corticospinal excitability able to discriminate between patients with quadriceps strength indicative of satisfactory and unsatisfactory knee function after ACLR.

METHODS

A total of 29 patients following primary, unilateral ACL-reconstruction (11 female, 23.2 ± 8.1 years of age, 7.3 ± 2.5 months since surgery) participated. Subjective knee function was quantified using the International Knee Documentation Committee (IKDC) subjective evaluation. Peak isokinetic knee extensor torque was assessed at 90°/s. Quadriceps corticospinal excitability was quantified via active motor threshold (AMT, %2-Tesla) using transcranial magnetic stimulation during a 5% maximal voluntary isometric contraction of the quadriceps. Pearson's r correlations were used to assess the relationship between peak knee extensor torque and AMT. Receiver operating characteristic (ROC) curves were used to establish a threshold of (a) mass-normalized peak knee extensor torque to discriminate satisfactory knee function (IKDC ≥ 75.9%), and (b) AMT to discriminate quadriceps strength indicative of satisfactory knee function. Likelihood ratios (LR) and the magnitude of change in pre-post-test probability were calculated for each threshold.

RESULTS

Active motor threshold was negatively correlated with mass-normalized peak knee extensor torque (r = -0.503, P = 0.005). Knee extensor torque ≥1.23 Nm/kg was an excellent discriminator of satisfactory knee function (AUC = 0.890, P = 0.002; (+)LR = 9.56). An AMT ≤50.5% was an excellent discriminator of quadriceps strength indicative of satisfactory knee function following ACLR (AUC = 0.839, P = 0.005; (+)LR = 23.75).

CONCLUSION

Lower corticospinal excitability was associated with lower quadriceps strength. An AMT above 50.5% was found to decrease the probability of having satisfactory knee strength by over 62%.

Quadriceps Torque, Peak Variability and Strength Endurance in Patients after Anterior Cruciate Ligament Reconstruction: Impact of Local Muscle Fatigue

We tested if ACL-reconstructed participants show a decreased quadriceps torque, a lower muscle endurance capacity and a higher peak torque variability compared to unimpaired control participants prior to and following local muscle fatigue. Participants (n = 19, 10 women; 25 ± 5yrs.) with unilateral hamstrings autograft ACL-reconstruction and a matched unimpaired control group were recruited. Participants performed two maximal isometric voluntary force (MIVF) contractions of the knee extensors. In between, standardized local muscle fatigue was induced. ACL-reconstructed knees display a lower peak torque of the knee extensors in comparison to the contralateral limb (3.2 ± .3Nm/kg vs. 3.5 ± .3 Nm/kg). Peak torque variability and fatigue resistance were not affected by local muscle fatigue (p > .05). Participants with ACL-reconstructed knees show a persistent quadriceps muscle dysfunction. This dysfunction and lower limb side asymmetries might be risk factors for ACL re-ruptures.

Relationship Between Physical Therapy Characteristics, Surgical Procedure, and Clinical Outcomes in Patients After ACL Reconstruction

Context: Postoperative rehabilitation is critical to optimize outcomes after anterior cruciate ligament reconstruction (ACLR). However, the relationship between physical therapy (PT) and clinical outcomes is unclear. Objective: To describe PT characteristics following ACLR and to assess the relationships between PT characteristics, surgical procedure, and clinical outcomes. Design: Cross-sectional. Setting: Laboratory. Patients (or Other Participants): A total of 60 patients (31 females/29 males, age = 22.4 [9.2] y, height = 171.7 [9.9] cm, and mass = 70.2 [14.7] kg) with a history of primary unilateral ACLR (53.6% patellar tendon and 46.4% hamstring) participated. Intervention(s): Patients completed a performance assessment and rated subjective knee function prior to physician clearance (mean = 6.3 [1.3] mo postoperatively) and were contacted within 6 months of clearance to complete a PT questionnaire. Main Outcome Measures: PT questionnaire item response, knee extension maximum voluntary isometric contraction (MVIC) torque, peak isokinetic knee extension torque, single leg hop distance, and International Knee Documentation Committee were measured. Correlations assessed relationships between PT quantity and clinical outcomes. Independent t tests compared PT quantity and clinical outcomes based on return-to-sport status, readiness to return to sport, and surgical procedure. Results: Patients completed regular PT (2 d/wk, 25 wk, 58 visits) and were most likely to conclude when discharged by the therapist (68.3%). More than half (56.7%) returned to sport, yet most (73.3%) felt unready at discharge. Isokinetic torque was correlated with days of PT/week (r = .29, P = .03). Isokinetic torque and hop symmetry were reduced in patients who returned to sport (P < .05). Patients who felt ready to return completed fewer weeks of PT (P < .05). Patients with a patellar tendon graft completed more days of PT/week and total visits, but demonstrated lower MVIC torque, MVIC symmetry, and isokinetic symmetry (P < .05). Conclusions: Many patients felt unready to return to sport at PT discharge. PT frequency was associated with isokinetic torque, yet this relationship was small. Outcomes were reduced in patients who returned to sport, suggesting premature resumption of preinjury activity.

Greater knee flexion excursion/moment in hopping is associated with better knee function following anterior cruciate ligament reconstruction

PURPOSE

Individuals with impaired knee function after anterior cruciate ligament reconstruction (ACLR) may be at greater risk of developing knee osteoarthritis related to abnormal knee joint movement and loading. The aim of this study was to assess the association between knee biomechanics and knee laxity during hopping and clinically assessed knee function (i.e., patient-reported knee function and hop tests) following ACLR.

METHODS

Sixty-six participants (23 women, mean age 28 ± 6 years, mean 18 ± 3 months following ACLR) completed a standardized single-leg hopping task. Three-dimensional movement analysis was used to assess knee flexion excursion and body weight/height normalized knee flexion moments during landing for the involved limb. Anterior-posterior knee laxity was assessed with a KT-1000 knee arthrometer. Participants then completed a patient-reported knee function questionnaire and three separate hop tests (% of uninvolved limb) and were divided into poor and satisfactory knee function groups (satisfactory: ≥85% patient-reported knee function and ≥ 85% hop test symmetry). Associations between knee function and hop biomechanics/knee laxity were assessed using logistic regression and interquartile range scaled odds ratios (OR^IQR).

RESULTS

Greater knee flexion excursion (OR^IQR 2.9, 95%CI 1.1-7.8), greater knee flexion moment (OR^IQR 4.9, 95%CI 1.6-14.3) and lesser knee laxity (OR^IQR 4.7, 95%CI 1.5-14.9) were significantly associated with greater odds of having satisfactory knee function (≥ 85% patient-reported knee function and ≥ 85% hop test symmetry).

CONCLUSION

Greater knee flexion excursion/moment during hop-landing and lesser knee laxity is associated with better patient-reported knee function and single-leg hop test performance following ACLR. Patients with lower levels of knee function following ACLR demonstrated hop-landing biomechanics previously associated with early patellofemoral osteoarthritis. Therefore, interventions aimed at improving hop landing biomechanics in people with poor knee function are likely required.

LEVEL OF EVIDENCE

III, Cross-sectional study.

The Association Between Passing Return-to-Sport Criteria and Second Anterior Cruciate Ligament Injury Risk: A Systematic Review With Meta-analysis

BACKGROUND

There is no consensus on the components of return-to-sport (RTS) testing following anterior cruciate ligament (ACL) reconstruction or whether passing RTS criteria can reduce a patient's risk of reinjury.

OBJECTIVES

To determine whether impartial, criteria-based RTS decisions are associated with less risk of a second ACL injury (either graft failure or contralateral ACL injury).

METHODS

In this systematic review with meta-analysis, the authors conducted an electronic literature search in PubMed/MEDLINE, Embase, CINAHL, SPORTDiscus, and ProQuest Dissertations and Theses Global using database-specific vocabulary related to ACL reconstruction and return to sport. Individual study quality was assessed using the modified Downs and Black checklist, and overall quality of evidence was determined with the Grading of Recommendations Assessment, Development and Evaluation scale. Pooled risk difference (passed versus failed RTS criteria), injury incidence proportion, and the diagnostic accuracy of each RTS criterion were calculated.

RESULTS

Four studies met the selection criteria. Overall, 42.7% (95% confidence interval [CI]: 18%, 69%) of patients passed RTS criteria, and 14.4% (95% CI: 8%, 21%) of those who passed experienced a second ACL injury (graft rupture or contralateral ACL injury). There was a nonsignificant 3% reduced risk of a second ACL injury after passing RTS criteria (risk difference, -3%; 95% CI: -16%, 10%; I² = 74%, P = .610). The evidence rating of the Grading of Recommendations Assessment, Development and Evaluation scale was "very low quality," due to imprecision and heterogeneity of the pooled risk difference estimate.

CONCLUSION

Passing RTS criteria did not show a statistically significant association with risk of a second ACL injury. The quality-of-evidence rating prevents a definitive conclusion on this question and indicates an opportunity for future research.

LEVEL OF EVIDENCE

Prognosis, Level 2a-. J Orthop Sports Phys Ther 2019;49(2):43-54. Epub 30 Nov 2018. doi:10.2519/jospt.2019.8190.

RESTORING KNEE EXTENSOR STRENGTH AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION: A CLINICAL COMMENTARY

One of the main priorities of rehabilitation after anterior cruciate ligament reconstruction (ACLR) surgery is the restoration of knee extensor muscle strength. Residual deficits in knee extensor muscle size and strength after injury are linked to poor biomechanics, reduced knee function, increased knee osteoarthritis risk, as well as heightened risk of re-injury upon return to sport. Most studies indicate that knee extensor muscle strength is typically not resolved prior to return to sport. This clinical commentary discusses strategies to optimize and accelerate the recovery of knee extensor strength post-surgery, with the purpose to support the clinician with evidence-based strategies to implement into clinical practice. Principally, two strategies exist to normalize quadriceps strength after surgery, 1) limiting strength loss after injury and surgery and 2) maximizing and accelerating the recovery of strength after surgery. Optimal preparation for surgery and a focused attempt to resolve arthrogenic muscle inhibition are essential in the pre and post-operative period prior to the inclusion of a periodized strength training program. Often voluntary strengthening alone is insufficient to fully restore knee extensor muscle strength and the use of electrical stimulation and where necessary the use of blood flow restriction training with low loads can support strength recovery, particularly in patients who are significantly load compromised and experience pain during exercise. Resistance training should employ all contraction modes, utilize open and closed kinetic chain exercise of both limbs, and progress from isolated to functional strength training, as part of a periodized approach to restoring neuromuscular function. Furthermore, thinking beyond the knee musculature and correcting core and hip dysfunction is also important to ensure an optimal knee extension strengthening program. The purpose of this clinical commentary is to provide a series of evidenced based strategies which can be implemented by clinicians responsible for the rehabilitation of patients after ACLR.

LEVEL OF EVIDENCE

5.

Cross-education does not improve early and late-phase rehabilitation outcomes after ACL reconstruction: a randomized controlled clinical trial

PURPOSE

Limited evidence suggests that cross-education affords clinical benefits in the initial 8 weeks after anterior cruciate ligament (ACL) reconstruction, but it is unknown if such cross-education effects are reproducible and still present in later phases of rehabilitation. We examined whether cross-education, as an adjuvant to standard therapy, would accelerate the rehabilitation up to 26 weeks after ACL reconstruction by attenuating quadriceps weakness.

METHODS

ACL-reconstructed patients were randomized into experimental (n = 22) and control groups (n = 21). Both groups received standard care after ACL reconstruction. In addition, the experimental group strength trained the quadriceps of the non-operated leg during weeks 1-12 after surgery (i.e., cross-education). Self-reported knee function was assessed with the Hughston Clinic Knee score as the primary outcome. Secondary outcomes were maximal quadriceps and hamstring strength and single leg hop distance. All outcomes were measured 29 ± 23 days prior to surgery, as a reference, and at 5-week, 12-week, and 26-week post-surgery.

RESULTS

Both groups scored 12% worse on self-reported knee function 5-week post-surgery (95% CI 7-17) and showed 15% improvement 26-week post-surgery (95% CI - 20 to - 10). No cross-education effect was found. Interestingly, males scored 8-10% worse than females at each time point post-surgery. None of 33 secondary outcomes showed a cross-education effect. At 26-week post-surgery, both legs improved maximal quadriceps (5-14%) and hamstring strength (7-18%), and the non-injured leg improved 2% in hop distance. The ACL recovery was not affected by limb dominance and age.

CONCLUSION

26 weeks of standard care improved self-reported knee function and maximal leg strength relative to pre-surgery and adding cross-education did not further accelerate ACL recovery.

LEVEL OF EVIDENCE

I.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION

This randomized controlled clinical trial is registered at the Dutch trial register ( http://www.trialregister.nl ) under NTR4395.

A research update on the state of play for return to sport after anterior cruciate ligament reconstruction

Most athletes who undergo anterior cruciate ligament (ACL) reconstruction surgery plan to return to some level of sporting activity. However, rates of return to pre-injury sport are often less than might be expected and many factors influence whether individuals return to sport after this surgery. They include surgical and rehabilitation factors as well as social, psychological and demographic characteristics. The fate of the younger athlete who sustains an ACL injury is a topic that has received recent attention due to accumulating evidence that younger athletes are at considerable risk for not only one, but multiple ACL injuries. 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. The notion that a set of return to sport criteria can be applied to reduce the risk of further injury has become popular with many different criteria proposed. Another risk of returning to sport following ACL reconstruction is that of sustaining injury to the menisci or articular surfaces, which may in turn increase the risk of developing osteoarthritis. Although there is some evidence that ACL reconstruction reduces the risk of osteoarthritis there is stronger evidence that it does little to protect the knee from long term degeneration. Therefore, it should be recognized that return to sport following ACL reconstruction is associated with a risk of further injury and potential development of osteoarthritis.Level of evidence: V.

Quadriceps Strength and Volitional Activation After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

Context:

Quadriceps function is a significant contributor to knee joint health that is influenced by central and peripheral factors, especially after anterior cruciate ligament reconstruction (ACLR).

Objective:

To assess differences of unilateral quadriceps isometric strength and activation between the involved limb and contralateral limb of individuals with ACLR and healthy controls.

Data Sources:

Web of Science, SportDISCUS, PubMed, CINAHL, and the Cochrane Database were all used during the search.

Study Selection:

A total of 2024 studies were reviewed. Twenty-eight studies including individuals with a unilateral history of ACLR, isometric knee extension strength normalized to body mass, and quadriceps activation measured by central activation ratios (CARs) through a superimposed burst technique were identified for meta-analysis. The methodological quality of relevant articles was assessed using a modified Downs and Black scale. Results of methodological quality assessment ranged from low to high quality (low, n = 10; moderate, n = 8; high, n = 10).

Study Design:

Meta-analysis.

Level of Evidence:

Level 2.

Data Extraction:

Means, standard deviations, and sample sizes were extracted from articles, and magnitude of between-limb and between-group differences were evaluated using a random-effects model meta-analysis approach to calculate combined pooled effect sizes (ESs) and 95% CIs. ESs were classified as weak (d < 0.19), small (d = 0.20-0.49), moderate (d = 0.50-0.79), or large (d > 0.80).

Results:

The involved limb of individuals with ACLR displayed lower knee extension strength compared with the contralateral limb (ES, –0.78; lower bound [LB], –0.99; upper bound [UB], –0.58) and healthy controls (ES, –0.76; LB, –0.98; UB, –0.53). The involved limb displayed a lower CAR compared with healthy controls (ES, –0.84; LB, –1.18; UB, –0.50) but not compared with the contralateral limb (ES, –0.15; LB, –0.37; UB, 0.07). The ACLR contralateral limb displayed a lower CAR (ES, –0.73; LB, –1.39; UB, –0.07) compared with healthy control limbs but similar knee extension strength (ES, –0.24; LB, –0.68; UB, –0.19).

Conclusion:

Individuals with ACLR have bilateral CAR deficits and involved limb strength deficits that persist years after surgery. Deficits in quadriceps function may have meaningful implications for patient-reported and objective outcomes, risk of reinjury, and long-term joint health after ACLR.

Systematic Selection of Key Logistic Regression Variables for Risk Prediction Analyses: A Five-Factor Maximum Model

GENERAL AND CRITICAL REVIEW FORMAT

The evolution of clinical practice and medical technology has yielded an increasing number of clinical measures and tests to assess a patient's progression and return to sport readiness after injury. The plethora of available tests may be burdensome to clinicians in the absence of evidence that demonstrates the utility of a given measurement.

OBJECTIVE

Thus, there is a critical need to identify a discrete number of metrics to capture during clinical assessment to effectively and concisely guide patient care.

DATA SOURCES

The data sources included Pubmed and PMC Pubmed Central articles on the topic. Therefore, we present a systematic approach to injury risk analyses and how this concept may be used in algorithms for risk analyses for primary anterior cruciate ligament (ACL) injury in healthy athletes and patients after ACL reconstruction.

MAIN RESULTS

In this article, we present the five-factor maximum model, which states that in any predictive model, a maximum of 5 variables will contribute in a meaningful manner to any risk factor analysis.

CONCLUSIONS

We demonstrate how this model already exists for prevention of primary ACL injury, how this model may guide development of the second ACL injury risk analysis, and how the five-factor maximum model may be applied across the injury spectrum for development of the injury risk analysis.

Editorial Commentary: Put Me Back Into The Game Coach! It's Time, I'm Ready: Time Is of No Essence After An Anterior Cruciate Ligament Reconstruction

Retear after an anterior cruciate ligament reconstruction is unavoidable. Many variables contribute to graft failure after anterior cruciate ligament reconstruction. Time from surgery to return to play is not the sole determinant. Graft maturation and symmetrical return of function need to be more carefully evaluated to reduce the risk of reinjury.