BRYAN CLARY, PABLO ALVAREZ, DAN HANSON, ANDY GEAN

Athletic ACL Injury Management

- Prehab

- Rehab

- Performance

- Prevention

Center for Sports Medicine and Orthopaedics

22 Physicians

9 Physician Assistants

2 Nurse Practitioners

42 Physical and Occupational Therapists

11 Athletic Trainers

375 total employees

10 Locations

Incidence and Impact of Injury

Growing Prevalence

1994 – 86,687

2013 – 148,714

$32,00-$50,000

Female Risk

2.3 – 9.7x higher incidence rate

Why Female?

Not Anthropometric

No increase in hip width

No correlation to notch width

Ligament Dominance

Quad Dominance

Leg Dominance

Sport Specialization? (DiCesare, 2019)

ACL Anatomy

Restricts anterior translation of

tibia on femur and extreme

tibial rotation

2 bundles

Anteromedial

Hyperextension

Full Flexion

Posterolateral

Hyperextension

Bundle strain vary

http://www.orthonet.pitt.edu/content/DoubleBundle.htm

Pathomechanics of Rupture

Non- Contact Knee valgus/internal tibial rotation on

relatively straight knee

Cutting, Single-leg landing, deceleration

Contact Hyperextension or valgus external

forces http://maxpotentialsports.files.wordpress.com/2013/06/acl-tear_valgus1.png

40 ms

70% N

on

–C

on

ta

ct I

nju

ry

Dynamic Q-Angle

Proximally

Femoral Adduction

Femoral IR

Distally

Pronation

Tibial internal Rotation

Associated Injuries

Ligament

Injuries

Articular

Cartilage

Injury

Bone

Bruise

Capsular

Injury

Meniscal

Injury

15% - 40% incidence with acute ACL

Higher rate of osteoarthritis

100% with meniscectomy

50% without meniscectomy (Jomha NM, 1999)

No convincing evidence that arthrosis can be

prevented by ACL reconstruction

Articular Cartilage

Injury

80% of ACL injuries have lateral compartment bone bruise

Hopeful resolvement by 6 months

Articular cartilage thinning possible

No correlation with pain level (Boks, 2007)

MCL reconstruction not advocated

Minimal separation = usually heals adequately Ligament

Injuries

Posterolateral corner injuries rare with ACL injury

Preoperative considerations

Standard is to achieve “quiet knee” (AJSM 2016)

Full ROM (Heijne)

No Pain

Quad Activation

Minimal Effusion

Bone bruise on the Lateral Femoral Condyle only predictor of delay in full extension (Gage 2019)

When to operate?

18 days (AJSM 1991)

3 weeks (AJSM 1992)

28 days (OJSM 2018)

“Prehab”

Phase 1 – Achieve quiet knee

Phase 2 – Restore muscle strength and neuromuscular

response

• Compared the patients of the Delaware-Oslo ACL Cohort to the MOON Cohort

• Athletes who underwent vigorous prehabilitationreturned to preinjury sport significantly higher (72%) than those in MOON, who did not. (63%)

Allograft vs Autograft - Stability

Sun et al. 2009.

86 BPTB autograph vs 86 BPTB allograft

Average follow up 5.6 years

No difference in stability found in Lachman test, pivot-shift, mean laxity with arthometer testing, or percentage of knees >3mm laxity

Most studies low level secondary to allograft sterilization techniques

45% rupture rate at 6 years with gamma irradiation (Gorschewsky et al, 2005)

Relatively equivalent stability

Autograft Stability – BPTB vs HS vs QT

Meta-Analysis of 6 RCT’s comparing HT vs BPTB at 2 years = No statistical difference in Lachman’s

BPTB – significantly decreased risk of positive pivot-shift

Spindler et al, 2004. Systematic review of 7 RCT’s

3 showed increased laxity with HS

2 of 3 used 2 strand HS graft

4 showed no difference

No significant difference between QT vs BPTB

Failure Rate – Allograft vs. Autograft

Kaeding et al. 2011.

allograft and younger age found to significantly increase risk of graft failure in first 2 years

7% more safe per year (Maletis et al, 2013)

Foster et al. 2010.

IKDC similar between allograft vs autograft

Allograft 8.2 per 100 failure vs 4.7 per 100 failure Autograft

Maletis, et al. 2013

9817 patients

Revision rates BPTB (1.18%) vs HS (1.56%) vs Allograft (1.74%)

98% vs 96.9% vs 96% survival at 2.7 years

What Graft for a 20 y/o Division 1 or NFL running back?

Criteria for running back return to play?

How long until return to play for running back?

Single bundle or double bundle for running back?

Knee brace?

What Graft for 25 y/o recreational athlete?

What Graft for 35 y/o recreational athlete?

(Erickson et al. 2014)

Running back?

86.1% BPTB.

99.3% autograft only

25 y/o recreational athlete?

49% BPTB

43% 4-strand HS

35 y/o recreational athlete?

45% 4-strand HS

What criteria for return to sport?

74.5% passed return to play testing

56.9% also require normal

ROM/pain/strength

Single vs Double?

99.3% Single

Brace?

64% say No

References

Beynnon, B. D. "Treatment Of Anterior Cruciate Ligament Injuries, Part I". American Journal of Sports Medicine 33.10 (2005): 1579-

1602. Web.

Wilk, K. (2015). Anterior Cruciate Ligament Injury Prevention and Rehabilitation: Let's Get It Right. Journal of Orthopaedic &

Sports Physical Therapy, 45(10), pp.729-730.

DiCesare, C., Montalvo, A., Barber Foss, K., Thomas, S., Ford, K., Hewett, T., Jayanthi, N., Stracciolini, A., Bell, D. and Myer, G. (2019). Lower Extremity Biomechanics Are Altered Across Maturation in Sport-Specialized Female Adolescent Athletes. Frontiers

in Pediatrics, 7.

Failla, M., Logerstedt, D., Grindem, H., Axe, M., Risberg, M., Engebretsen, L., Huston, L., Spindler, K. and Snyder-Mackler, L. (2016). Does Extended Preoperative Rehabilitation Influence Outcomes 2 Years After ACL Reconstruction?. The American Journal of

Sports Medicine, 44(10), pp.2608-2614.

Heijne A, Ang BO, Werner S. Predictive factors for 12-month outcome after anterior cruciate ligament reconstruction. Scand J

Med Sci Sports. 2009;19(6):842-849.

Gage, A., Kluczynski, M., Bisson, L. and Marzo, J. (2019). Factors Associated With a Delay in Achieving Full Knee Extension Before Anterior Cruciate Ligament Reconstruction. Orthopaedic Journal of Sports Medicine, 7(3), p.232596711982954.

Shelbourne KD, Wilckens JH, Mollabashy A, DeCarlo M. Arthrofibrosis in acute anterior cruciate ligament reconstruction: the

effect of timing of reconstruction and rehabilitation. Am J Sports Med. 1991; 19(4):332-336.

Harner CD, Irrgang JJ, Paul J, Dearwater S, Fu FH. Loss of motion after anterior cruciate ligament reconstruction. Am J Sports

Med. 1992;20(5):499-506.

References

Huleatt J, Gottschalk M, Fraser K, et al. Risk factors for manipulation under anesthesia and/or lysis of adhesions after anterior cruciate ligament reconstruction. Orthop J Sports Med. 2018;6(9): 2325967118794490.

Eitzen, I., Moksnes, H., Snyder-Mackler, L. and Risberg, M. (2010). A Progressive 5-Week Exercise Therapy Program Leads to Significant Improvement in Knee Function Early After Anterior Cruciate Ligament Injury. Journal of Orthopaedic & Sports Physical Therapy, 40(11), pp.705-721.

Kaeding C, Aros B, Pedroza A, et al. Allograft versus autograft anterior cruciate ligament reconstruction: predictors of failure from a MOON prospective longitudinal cohort. Sports Health. 2011;3(1):9.

Foster TE, Wolfe BL, Ryan S, Silvestri L, Kaye EK. Does the graft source really matter in the outcome of patients undergoing anterior cruciate ligament reconstruction? An evaluation of autograft versus allograft reconstruction results: A systematic review. Am J Sports Med 2010

Maletis GB, Inacio MC, Desmond JL, Funahashi TT. Reconstruction of the anterior cruciate ligament: association of graft choice with increased risk of early revision. Bone Joint J 2013; 95-B: 623-628 [PMID: 23632671 DOI: 10.1302/0301-620 X.95B5.30872

Sun K, Tian SQ, Zhang JH, Xia CS, Zhang CL, Yu TB. Anterior cruciate ligament reconstruction with bone-patellar tendon-bone autograft versus allograft. Arthroscopy. 2009;25(7):750-759.

Spindler KP, Kuhn JE, Freedman KB, Matthews CE, Dittus RS, Harrell FE Jr. Anterior cruciate ligament reconstruction autograft choice: bone-tendonbone versus hamstring: does it really matter? A systematic review. Am J Sports Med. 2004;32(8):1986-1995.

BEYOND PROTOCOLS

PABLO ALVAREZ, PT, MSPT

ACL REHABILITATION

FOR THE ATHLETE

OBJECTIVES

•Whole Body Approach

•Minimizing Compensations

•Cardiovascular Demands

•Dynamic Readiness

•Nutrition

•Psychological Implications

•Restoring Strength

Whole Body Approach

Clear joint above and below…….but

then what?

Core/Trunk Control

TS and UE

Mobility and Flexibility

Cardiovascular Demands

Increase Blood Flow

Caloric Demands

Maintain Conditioning

TUNNEL VISION

Minimize Compensations

• How do you identify Compensations?

• Easy to hide for Athletes

• FMS/SFMA

• Do you know how to evaluate and

correct a Squat?

• Coach every repetition!!!

Dynamic Readiness

What does it

mean to by

Dynamic?

Early

Introduction

Hand eye

coordination

Nutritional Considerations

Eating for Rehab

Cleveland Clinic – Our bodies need more calories, protein, vitamins to promote healing

Foods that control Inflammation

Pre and Post Therapy Nutrition

Weight Control

Both losing and gaining weight can be a problem

Hydration

MUST “Have The Talk”

Coordinate with a Nutritionist /Dietician

Psychological Considerations

Negative Consequences

of dealing with an Injury

• Anxiety

• Stress

• Depression

Intervention Techniques

▪ Effective Communication

▪ Goal Setting

▪ Relaxation and Breathing Techniques

▪ Motivation

▪ Create a positive environment for your athletes

Restoring Strength

Early quad activation

Early Extension Vital

OCK vs CKC

JOSPT (2018)

Flemming et al. 2005

BFR

Sudo et al. 2017

BFR induces muscle fiber hypertrophy

Slysz et al. 2016

Low Load w/ BFR = exaggerated response

Restoring Strength

Periodization

Appropriate Progression

3 Sets of 10…….WHY???

Strength vs Power vs Hypertrophy

Therapy Done…Now What?

Transition to Performance Training

References

Sudo, M., Ando, S., & Kano, Y. (2017) Repeated BFR induces muscle fiber hypertrophy. Muscle Nerve, 55(2) 274-276

Slysz, J., Stultz, J. & Burr, J.F. (2016). The efficacy of blood flow restricted exercise: A systematic review & meta-analysis. J Sci Med Sport 19(8), 669-675

Keylock, K., Young, H. (2010). Delayed would healing: Can exercise accelerate it? Int J Exercise Science. 2010; 3(3): 70-78

Craft, LL., Perna, F., The benefits of exercise of the clinically depressed. Prim Companion J Clin Psychiatry. 2004;6(3): 104-11

https://my.clevelandclinic.org/health/articles/11111-nutrition-guidelines-to-improve-wound-healing

FLEMING, B.C., H. OKSENDAHL, and B.D. BEYNNON. Open- or closed-kinetic chain exercises after anterior cruciate ligament reconstruction? Exerc. Sport Sci. Rev., Vol. 33, No. 3, pp. 134–140, 2005.

THANK YOU!

CSCS, USAW-L1

SPORTS PERFORMANCE COACH

Dan Hanson

Fundamentals of Strength Training

Strength ≠ Hypertrophy

- Work Capacity (early)

- High repetition (15-20)

- Metabolic conditioning : can be integrated w/ deceleration +

linear speed training

- Deceleration/landing exercises are relatively low intensity + higher

volume

Strength Phase

- :Phasic Potentiation

- : heavy compound lifts (trap bar deadlift/BB Squat)

*heavy is relative!

- : 3-8 reps/3-5 sets per exercise (*don’t live in 3x10)

- : complimented with unilateral eccentric accessories (maintaining

secondary/retaining load – hypertrophy)

- : more aggressive deceleration/landing exercises with lower

volume

Strength Training Post-Rehab

“While squat progressions are well known (yet

amazingly still under-utilized), very few protocols

incorporate deadlifts and if they do, it is often in a

single-leg platform with a balance emphasis.

Additionally, hamstring weakness when matched

to their male counterparts, as opposed to

quadriceps weakness, may be a bigger predictor

for ACL injury and subsequent re-injury in females

(G.D. Myer, 2009).”

Strength Training Post-Rehab (cont.)

“The deadlift (and barbell squat)

addresses core strength to a greater

extent than conventional “core”

exercises (Hamlyn N, 2007).”

Speed (linear vs. COD)

Deceleration = Eccentric Quad Strength + Isometric Post. Chain

Strength

Bilateral Deceleration + Unilateral Deceleration (w/ support)

1) Linear Speed (straight line – Jog vs Run vs Walk)

2) Lateral Linear Speed (shuffling and/or running straight line)

3) Linear COD (sprint/shuffle/backpedal straight line)

4) Multi-Directional COD

Closed → Open

Closed → Open : Change of Direction

“Closed” Directional Movement

- used early in training process

- ex: T-Drill, Pro Agility (5-10-5), Square Drill

“Open” Directional Movement

- advanced drills in training process

- variety of coaches cues

: verbal (clap/whistle/”go!”)

: visual (point/ball toss/partner reaction)

Jumping/Landing

Lots of small landing success early on (fwd, bilateral)

Creating Force vs Absorbing Force

Mio Jumps – “Short and successful!”

Later expand to different directions

: Bilateral Landing + Rotation, Bilateral Broad Jump

: Unilateral Skater, Unilateral 45 deg Skater

: Advanced Stages – add perturbation

*these can be done with limited space and little to no

equipment

“what I need to see to feel good

about you returning to sport”

Linear Speed (can you sprint?)

Deceleration (can you decelerate from a full sprint?)

Open COD (can you change direction with an open cue?)

ROM (can you squat full ROM? *excluding other limiting factors)

Core Stability (Horizontal Trunk Hold/Elbow Plank *strength vs endurance)

RTS – “Assessments should be

descriptive, not predictive.”

90%??

Unilateral Jump/Land

“Eye Test”

What are the demands of sport? The ultimate goal of

performance training is to prepare the athlete for the

demands of sport.

ANDY GEAN, PT, DPT, OCS, COMT

Evidence for

Return to Sport

Decision-Making

The Question

One of the most complex questions in

sports medicine

When?

Based on what criteria?

Relevant factors?

Level of “readiness”?

Inherent risks?

When can I play

again?

Athlete

Parent

CoachATC

Parent

When Athletes Do Return…

Clin J Sports Med 2012

63 patients < 25 y.o.

25.4% risk of susequent ACL Injury within 12 mos of RTS

15x greater risk than controls

Females:

4x greater ipslilat, 6x greater contralat injury likelihood than males

Am J Sports Med 2016

242 patients <18 y.o.

31% risk for subsequent injury

2nd Injury

First 12 months post-ACLR: 50% of graft ruptures occur during this time

Age < 20: Graft rupture and contralat injury more common

BJSM 2014

Meta-Analysis 7556 individuals, 69 studies

81% returned to any sport

65% returned to pre-injury level of sport

55% returned to pre-injury competitive level (production/performance)

Return to Sport

Factors Age

Gender (?)

Sport

Competitive Level

Timing of season

Psychological readiness

External factors

Concomitant Procedure

Minimal Criteria

Full joint motion

No swelling

Joint stability

KT-1000

<3 mm side to side difference

Return to Sport:

Progressive, multi-level continuum of

assessment

The Return-to-Sport Question:

What objective, qualitative data do I need to consider in assisting with the RTS decision?

Does objective data aid in making an informed decision?

A Proposed RTS Checklist

Hewett & Webster CJSM 2017

Kinesthesia, Balance, Proprioception

Movement Biomechanics

Laxity, Graft, Bone Bruise, Anthropometrics

Strength, Power, (and Fatigue?)

Psychological Factors and Demographics

CSMO ACL RTS Checklist:• FMS, YBT: 12 weeks

• Strength Testing: 4+

months

• Hop Testing: 5+ months

• Normalization of jump,

landing biomechanics

• Field Tests• OFR→RTT→RTC→RTP

Kinesthesia, Balance, Propropception• Y Balance Test (Star Excursion Balance

Test)

• Objective, single leg motor control

• “Functional goniometer”

• Thresholds:• Anterior (<4 cm difference)

• Posterior medial (<6 cm)

• Posterior lateral (<6cm)

• Composite: >90-95% relative to limb

length

• Performance on YBT at 12 wks post-ACLR

correlated with passing hop tests at 6

mos• Garrison et al. IJSPT

• Statistically significant relationship

between anterior reach and knee

extensor deficits• Myers et al. IJSPT

Strength

Post-op deficits: debilitating, ubiquitous

Strength: Must quantify and normalize

90% of contralateral (or greater)

Knee flexors and extensors

Deficits vary by graft

Extensors: quad, BPTB grafts

Flexors: HS graft

Goals:

Minimize extensor deficits

Females: Commonly “quad dominant” →Restore Q:HS ratio

Objective Strength Measures:

Isokinetic

Peak flexor, extensor force at 60, 120, 180 deg/s

Quad:HS ratio

Peak torque:Body weight

Hand Held Dynamometry

Rep Max: 1 RM, 10 RM

Commonly assessed at 3 (?), 6, 9, 12+ months

Restory Limb Symmetry

Many movements remain asymmetric, abnormal several months post-ACLR

LSI commonly utilized post ACLR

Strength

Hop tests

Double limb squat

Video, pressure sensor mat (ex. Boditrak): L/R symmetry

Single limb squat

Quality reps to fatigue

Double limb vertical jump

Video, pressure sensor mat (Boditrak): L/R take off, landing symmetry

Single limb vertical jump

Jump mat L vs R

App

Single limb hop test

Single hop for distance, triple hop for distance, triple crossover

Restoring Limb Symmetry: Hop Tests

Most Researched

Single limb hop test

Single

Triple

Triple-cross

6 m time

Variations

Less researched

Timed lateral hop: 30 sec, two lines 40 cm apart, record number of side to side hops

Medial rotation hop: 90 deg medial rot→hop for distance

Restoring Limb

Symmetry: Hop

Tests

Single limb hop test

Single

Triple

Triple-cross

Timed lateral hop

Medial rotation hop:

Movement Quality

Body weight x 1: Functional

Movement Screen

Screen - NOT Predictive

Identify dysfunctional and/or painful

movements

7 Fundamental movement patterns

Double and single limb

Upper extremity

Core

Symmetric and asymmetric patterns

Jump/Landing Tasks:

Paterno et al: Landing mechanics

associated w/ 2nd injury

Assessment: Double, single leg

landing/jumps

Ground Reaction Force: 2-6x BW

Most accurately measured on force

plates

Video analysis correlates with force

plate measures

Clinical Tool: Landing Error Scoring

System (LESS)

Functional Movement Screen

4.7x greater injury rate if score <17

Letafatkar IJSPT 2014

Female collegiate athletes: 4x greater chance of LE injury if score < 14

SN:0 0.58, SP: 0.74

Chorba NAJSPT 2010

Professional Football: Score of <15 →Associated with serious LE injury

SN: 0.54, SP: 0.91

Kiesel NAJSPT 2007

LESS (Landing Error Scoring System)

Clinical Tool: Landing

Error Scoring System

Double leg drop

jump

Video assessment

19 Items scored: 0

(Good), 1

(Deduction)

Lower risk: <5, Higher

risk: >5

Landing Mechanics & 2nd Injury

Variables Predictive of 2nd

injury:

Net Hip IR (dynamic valgus)

moment at landing

Unequal sagittal (L/R) knee

moment at landing

2-D frontal plane (valgus)

knee excursion

56 female athletes: 13 2nd

ACL injury with 1 year

SN: 0.92, SP: 0.88

RTS Batteries

• Do RTS batteries have clinical utility?

• Hewett & Webster Sports Med2019

• Meta-Analysis • Passing RTS criteria reduced risk

graft rupture by 60%• Only 23% passed RTS criteria

• Increased the risk of contralateral ACL rupture by 235%

• Questionable Inclusion Criteria

RTS Batteries

• Re-analysis: Passing RTS batteries• Decreased risk of further knee injury by

72% • Decreased odds of any ACL injury by

75%• Decreased odds of ACL graft rupture by

78%

• High risk• Younger• Higher activity level• Earlier return to sport

Biological Factors

Nagelli Sports Med 2016

Younger population: majority of reinjury within 2 years of ACLR

Relative risk may decrease thereafter

Biological: Allow restoration of baseline joint homeostasis

Resolution of bone bruises (5-12 mos)

Allow graft maturation (HSG 12-24 mos, PTG 6-12)

Neuromuscular improvements up to 24 mos post-ACLR

Psychological Readiness

Factors Associated With Psychological Readiness to Return to Sport After Anterior Cruciate Ligament Reconstruction Surgery.

Webster AJSM 2018

Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI) Scale

6 Item=12 Item Form

Higher score → Greater subjective readiness

Greater Readiness

Males

Younger

Shorter interval between injury, surgery

Higher frequency pre-injury sport participation

Higher subjective knee scores (IKDC)

Greater limb symmetry

Lower Readiness

Females

Lower subjective knee scores (IKDC)

Psychological Readiness and 2nd ACL

Injury

Psychological Readiness to Return

to Sport Is Associated With Second

Anterior Cruciate Ligament

Injuries.

McPherson AJSM 2019

ACL-RSI

Before surgery

12 months after surgery

329 patients, 52 second ACL injury

Results:

Higher Risk

Younger

Lower ACL-RSI Scale Scores

Lower Risk

90% Sensitivity: 76.7%

RTP

• 4.32x higher re-injury for athletes returning to level 1 sports

• Reinjury rates were “significantly reduced by 51% for each month RTS was

delayed until 9 months after surgery

• Reinjury Rates:

• Failed to pass RTS battery: 38.2% re-injury rate

• Passed all RTS (strength >90%, hop tests): 5.6% re-injury rate.

• More symmetric quadricep strength (>90% symmetry) associated with

lower re-injury rates

Field Tests

T Test

Pro-Agility

Reference:

Preseason

performance

Normative

Data

Returning to the Field

Buckthorpe JOSPT

2019

OFR •On-Field Rehab

RTT •Return to Training

RTC•Return to Competition

RTP •Return to Performance

Secondary “Prevention”

1st Injury: Devastating → 2nd Injury: Life-Changing

What Can I Do? Modify the Modifiable!

Strength

Neuromuscular Re-training

Calculated RTS Timing

Recognize Additional Factors:

Psychological

Concomitant Procedure

Meniscal, Cartilaginous, MLKI

Progressive, graduated rehab & RTP progression

Coordinated, collaborative RTS/RTP decision-making with stakeholders

Primary Prevention

Programs: Sportsmetrics, FIFA 11, 11+, Prevent Injury and Enhance Performance (PEP)

Recommendations: <18 yo male & FEMALE, preseason, multiple times/wk, typically 6+ weeks

Components: strength, proximal control, and plyometric

Conclusion

RTS Testing Battery:

Improve “readiness”, reduce risk

Progressive battery of test most commonly

utilized and supported by evidence

Timing of RTS

Early, Younger: Greater risk

Delaying Factors:

Biological Factors

Psychological Factors

Modify the modifiable

Build a solid foundation

References Webster KE, Nagelli CV, Hewett TE, Feller JA. Factors Associated With Psychological Readiness to Return to Sport After Anterior Cruciate Ligament Reconstruction Surgery. Am J Sports Med. 2018 Jun;46(7):1545-1550.

McPherson AL, Feller JA, Hewett TE, Webster KE. Psychological Readiness to Return to Sport Is Associated With Second Anterior Cruciate Ligament Injuries. Am J Sports Med. 2019 Mar;47(4):857-862.

Amelia J.H. Arundale, Mario Bizzini, Airelle Giordano, Timothy E. Hewett, David S. Logerstedt, Bert Mandelbaum, David A. Scalzitti, Holly Silvers-Granelli, and Lynn Snyder-Mackler Exercise-Based Knee and Anterior Cruciate Ligament Injury Prevention. Journal of Orthopaedic& Sports Physical Therapy 2018 48:9, A1-A42 .

Capin JJ, et al. Keep calm and carry on testing: a substantive reanalysis and critique of ‘what is the evidence for and validity of return-to-sport testing after anterior cruciate ligament reconstruction surgery? A systematic review and metaanalysis’. Br J Sports Med 2019 Editorial.

Webster KE, Hewett TE. What is the Evidence for and Validity of Return-to-Sport Testing after Anterior Cruciate Ligament Reconstruction Surgery? A Systematic Review and Meta-Analysis. Sports Med. 2019 Jun;49(6):917-929.

Nagelli CV, Hewett TE. Should Return to Sport be Delayed Until 2 Years After Anterior Cruciate Ligament Reconstruction? Biological and Functional Considerations. Sports Med. 2017 Feb;47(2):221-232.

Grindem H, Snyder-Mackler L, Moksnes H, Engebretsen L, Risberg MA. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. Br J Sports Med. 2016 Jul;50(13):804-8.

Garrison JC, Bothwell JM, Wolf G, Aryal, Thigpen CA. Y BALANCE TEST™ ANTERIOR REACH SYMMETRY AT THREE MONTHS IS RELATED TO SINGLE LEG FUNCTIONAL PERFORMANCE AT TIME OF RETURN TO SPORTS FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION. Int J Sports Phys Ther. 2015 Oct; 10(5): 602–611.

Myers H, Christopherson Z, Butler RJ. RELATIONSHIP BETWEEN THE LOWER QUARTER Y-BALANCE TEST SCORES AND ISOKINETIC STRENGTH TESTING IN PATIENTS STATUS POST ACL RECONSTRUCTION. Int J Sports Phys Ther. 2018 Apr; 13(2): 152–159.

Ardern CL, Taylor NF, Feller JA, et al Fifty-five per cent return to competitive sport following anterior cruciate ligament reconstruction surgery: an updated systematic review and meta-analysis including aspects of physical functioning and contextual factors British Journal of Sports Medicine 2014;48:1543-1552.

Lai CCH, Ardern CL, Feller JA, et al Eighty-three per cent of elite athletes return to preinjury sport after anterior cruciate ligament reconstruction: a systematic review with meta-analysis of return to sport rates, graft rupture rates and performance outcomes British Journal of Sports Medicine 2018;52:128-138.

Wiggins AJ, Grandhi RK, Schneider DK, Stanfield D, Webster KE, Myer GD. Risk of Secondary Injury in Younger Athletes After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis. Am J Sports Med. 2016;44(7):1861–1876. doi:10.1177/0363546515621554.

Morgan, M. D., Salmon, L. J., Waller, A., Roe, J. P., & Pinczewski, L. A. (2016). Fifteen-Year Survival of Endoscopic Anterior Cruciate Ligament Reconstruction in Patients Aged 18 Years and Younger. The American Journal of Sports Medicine, 44(2), 384–392. https://doi.org/10.1177/0363546515623032

Timothy E. Hewett, Kate E. Webster, Wendy J. Hurd. Systematic Selection of Key Logistic Regression Variables for Risk Prediction Analyses: A Five Factor Maximum Model. Clin J Sport Med. 2019 Jan; 29(1): 78–85. doi: 10.1097/JSM.0000000000000486

Paterno, MV, Schmitt, LC, Ford, KR. Biomechanical measures during landing and postural stability predict second anterior cruciate ligament injury after anterior cruciate ligament reconstruction and return to sport. Am J Sports Med. 2010;38(10):1968–1978.

Buckthorpe M, Della Villa F, Della Villa S, Roi GS. On-field Rehabilitation Part 1: 4 Pillars of High-Quality On-field Rehabilitation Are Restoring Movement Quality, Physical Conditioning, Restoring Sport-Specific Skills, and Progressively Developing Chronic Training Load. J OrthopSports Phys Ther. 2019 Aug;49(8):565-569. doi: 10.2519/jospt.2019.8954. Epub 2019 Jul 10.