Weight Bearing Vs Non-Weight Bearing Exercises for Anterior
Cruciate Ligament (ACL) Injuries
G. Kelley Fitzgerald, PT, PhD, OCSG. Kelley Fitzgerald, PT, PhD, OCS
Department of Physical TherapyDepartment of Physical TherapySchool of Health and Rehabilitation SciencesSchool of Health and Rehabilitation Sciences
University of PittsburghUniversity of Pittsburgh
Weight Bearing Vs Non-Weight Bearing Exercises for ACL Injuries
nn Safety IssuesSafety Issuesuu ACL StrainACL Strain
uu Patellar Tendon Patellar Tendon AutograftAutograft Donor SiteDonor Site
nn Review of Randomized Clinical TrialsReview of Randomized Clinical Trials
Safety Issues: Excessive Strain on Graft?
nnNWB place excessive strain on the NWB place excessive strain on the graftgraft
nnWB involves less anterior shear, WB involves less anterior shear, therefore less strain on grafttherefore less strain on graft
nnWB results in greater joint WB results in greater joint compression, adding stability to the compression, adding stability to the joint during exercisejoint during exercise
Henning, et al, Am J Sports Med. 1985
nn Measured strain in ant. bundle of Measured strain in ant. bundle of partially torn ACL(N=2)partially torn ACL(N=2)
nn Strain measured during NWB Strain measured during NWB and WB activitiesand WB activities
nn Strain measurements normalized Strain measurements normalized to 80lb Lachman testto 80lb Lachman test
nn NWB leg extensions through full NWB leg extensions through full ROM may be harmful to graftROM may be harmful to graft
Henning, et al, Am J Sports Med. 1985
nn Strain behavior in Strain behavior in injured ACL and injured ACL and ACL graft may not ACL graft may not be samebe same
nn Large variability in Large variability in strain between 2 strain between 2 subjectssubjects
nn Data has limited Data has limited valuevalue 0 20 40 60 80 100 120 140
half squat
walking
ext 0-20
iso q 45
iso q 22
subj 1 subj 2
Anterior Tibial Translation As Indirect Measure of ACL Strain
nn Howell, Howell, AM J Sports Med, 1990AM J Sports Med, 1990
nn Yack, et al, Yack, et al, AM J Sports Med, 1993AM J Sports Med, 1993
nn Jenkins, et al, Jenkins, et al, JOSPT, 1997JOSPT, 1997
Howell, AM J Sports Med, 1990
nn Measured tibial translation during quad Measured tibial translation during quad MVIC at 15°,30°,45°,60°, and 75° of knee flexMVIC at 15°,30°,45°,60°, and 75° of knee flex
nn 22 controls, 10 ACL deficient, 10 ACL 22 controls, 10 ACL deficient, 10 ACL reconstructed kneesreconstructed knees
nn Translation occurred at 15 Translation occurred at 15 -- 60 for all groups60 for all groups
nn Significantly less when compared to 89N Significantly less when compared to 89N and Max Manual KT 1000 testingand Max Manual KT 1000 testing
nn Amount of tibial translation during quad Amount of tibial translation during quad MVIC may not be clinically relevant.MVIC may not be clinically relevant.
Yack, et al, AM J Sports Med, 1993
nn 11 subjects with ACLD11 subjects with ACLDnn Measured anterior tibial translationMeasured anterior tibial translationnn Leg extension vs squatLeg extension vs squatnn Greater anterior tibial translation with Greater anterior tibial translation with
leg extension exercise at knee leg extension exercise at knee flexion angles less than 64°flexion angles less than 64°
Jenkins, et al, JOSPT, 1997
nn Measured ant tibial translation Measured ant tibial translation isometric leg extension and leg press isometric leg extension and leg press at 30° and 60° of knee flexionat 30° and 60° of knee flexion
nn 19 ACL deficient knees19 ACL deficient kneesnn Greater anterior tibial translation Greater anterior tibial translation
during isometric leg extension at 30°during isometric leg extension at 30°
Anterior Translation Vs ACL Strain?
nn Based on evidence, translation may Based on evidence, translation may be minimized if quad contractions be minimized if quad contractions are performed at angles greater than are performed at angles greater than 60°60°
nn Increased translation does not Increased translation does not necessarily translate to harmful ACL necessarily translate to harmful ACL or ACL Graft strainor ACL Graft strain
Beynnon BD, Johnson RJ, Fleming BC. The Science of Anterior Cruciate Ligament Rehabilitation. Clin Orthop. 2002;402:9-20
nn Review of a series of experimental studies Review of a series of experimental studies measuring Inmeasuring In--Vivo ACL strain during a variety Vivo ACL strain during a variety of WB and NWB activitiesof WB and NWB activities
nn Strain Strain guageguage inserted into anteriorinserted into anterior--medial medial bundle of intact ACL during arthroscopybundle of intact ACL during arthroscopy
nn Strain measures were referenced to Strain measures were referenced to differential length of ACL between unloaded differential length of ACL between unloaded and 200N anterior shear loadand 200N anterior shear load
Beynnon BD, Johnson RJ, Fleming BC. The Science of Anterior Cruciate Ligament Rehabilitation. Clin Orthop. 2002;402:9-20
18182.7%2.7%NWBNWBIsometric Quad , Isometric Quad , 3030°°°° flexion, 30 Nmflexion, 30 Nm
552.1%2.1%WBWBStair ClimbingStair Climbing
883.6%3.6%WBWBSquattingSquatting
663.5%3.5%NWBNWBIsometric Isometric GastrGastr, 15, 15°°°°flexion, 15 Nmflexion, 15 Nm
884.0%4.0%WBWBSquatting with Squatting with Sport CordSport Cord
884.4%4.4%NWBNWBIsometric Quad , Isometric Quad , 1515°°°° flexion, 30 Nmflexion, 30 Nm
# Subjects# SubjectsPeak StrainPeak StrainTypeTypeRehab ActivityRehab Activity
Beynnon BD, Johnson RJ, Fleming BC. The Science of Anterior Cruciate Ligament Rehabilitation. Clin Orthop. 2002;402:9-20
88NWBNWB 0.0%0.0%
88NWBNWB 0.0%0.0%
Quad/Hamstring CoQuad/Hamstring Co--Contraction, 60 and Contraction, 60 and 9090°°°°
880.4%0.4%NWBNWBQuad/Hamstring CoQuad/Hamstring Co--Contraction, 30Contraction, 30°°°°
660.2%0.2%NWBNWBIsometric Isometric GastrGastr, 30, 30°°°°flexion, 15 Nmflexion, 15 Nm
Isometric Hamstring, Isometric Hamstring, 3030°°°° , 60, 60°°°° , 90, 90°°°° , 10Nm, 10Nm
880.6%0.6%NWBNWBIsometric Hamstring, Isometric Hamstring, 1515°°°° , 10Nm, 10Nm
880.0%0.0%NWBNWBIsometric Quad , 60Isometric Quad , 60°°°°and 90 and 90 °°°° flexion, 30 flexion, 30 NmNm
# Subjects# SubjectsPeak StrainPeak StrainTypeTypeRehab ActivityRehab Activity
Fleming BC, Renstrom PA, Beynnon BD, et al. The effect of weightbearing and external loading on anterior cruciate ligament strain. J of Biomech. 2001;34:163-170
nn Strain Strain guageguage inserted into anterior medial inserted into anterior medial bundle of ACL in 11 subjects bundle of ACL in 11 subjects
nn Compression load of 40% body weight to Compression load of 40% body weight to simulate bilateral stance loadsimulate bilateral stance load
nn Compared ACL strain between compression Compared ACL strain between compression vsvs nonnon--compression condition for:compression condition for:uu AnteriorAnterior--Posterior ShearPosterior Shear
uu Internal and External Rotation TorquesInternal and External Rotation Torques
uu VarusVarus and and ValgusValgus TorquesTorques
Fleming BC, Renstrom PA, Beynnon BD, et al. The effect of weightbearing and external loading on anterior cruciate ligament strain. J of Biomech. 2001;34:163-170
Fleming BC, Renstrom PA, Beynnon BD, et al. The effect of weightbearing and external loading on anterior cruciate ligament strain. J of Biomech. 2001;34:163-170
Fleming BC, Renstrom PA, Beynnon BD, et al. The effect of weightbearing and external loading on anterior cruciate ligament strain. J of Biomech. 2001;34:163-170
Fleming BC, Renstrom PA, Beynnon BD, et al. The effect of weightbearing and external loading on anterior cruciate ligament strain. J of Biomech. 2001;34:163-170
Fleming BC, Renstrom PA, Beynnon BD, et al.The effect of weightbearing and external loading on anterior cruciate ligament strain. J of Biomech. 2001;34:163-170
nn Weight bearing may not be as Weight bearing may not be as protective as we think.protective as we think.
nn The rationale that weight bearing The rationale that weight bearing protects the ACL for supporting the use protects the ACL for supporting the use of WB exercise may be in error.of WB exercise may be in error.
Implications from the Data
nn The level of strain recorded in the The level of strain recorded in the various activities do not seem to be very various activities do not seem to be very highhigh
nn Greater external loads will result in Greater external loads will result in greater straingreater strain
nn Differences in ACL strain between WB Differences in ACL strain between WB and NWB may not be meaningfuland NWB may not be meaningful
nn With properly placed ACL graft, strain With properly placed ACL graft, strain patterns between WB and NWB patterns between WB and NWB exercise may be similarexercise may be similar
nn WB activities may not really reduce the WB activities may not really reduce the strain in the ACL when other combined strain in the ACL when other combined loads are appliedloads are applied
Should The Absence of Strain Really Be The Goal?
nn Some tension and strain may Some tension and strain may actually enhance the histological actually enhance the histological quality and tensile strength of the quality and tensile strength of the healing ligamenthealing ligament
nn What is not known is the critical What is not known is the critical value between helpful vs harmful value between helpful vs harmful strainstrain
Safety Issues: B-PT-B Donor Site
Sharkey, et al. Patellar strain and patellofemoral contact after bone-patellar-bone tendon harvest for anterior cruciate ligament reconstruction. Arch Phys Med Rehab, 1997.
Implications in Post-op B-PT-B Autograft Reconstruction Rehabnn Careful not to overload the quadriceps in Careful not to overload the quadriceps in
positions of greater knee flexion (>60 positions of greater knee flexion (>60 degrees) in early stages of rehab following degrees) in early stages of rehab following BB--PTPT--B B autograftautograft..
nn Donor site may need about 6Donor site may need about 6--8 weeks to heal 8 weeks to heal before it can tolerate aggressive loadingbefore it can tolerate aggressive loading
nn Can initiate resistance exercises early but Can initiate resistance exercises early but provide enough time for donor site healing provide enough time for donor site healing before aggressive progression is initiatedbefore aggressive progression is initiated
Clinical Trials Comparing WB and NWB Exercise in Post ACL Reconstruction Rehabilitation
Bynum, et al, 1995Bynum, et al, 1995
Morrissey, et al, 2000Morrissey, et al, 2000
MikkelsenMikkelsen, et al, 2000, et al, 2000
Bynum BE, Barrack RL, Alexander AH. Open Vs Closed Chain Kinetic Exercises After ACL Reconstruction. Am J Sports Med. 1995;23:401-406.
nn 97 Subjects, B97 Subjects, B--PTPT--B, B, autograftautograft
nn Randomly assigned to NWB (N = 47) or Randomly assigned to NWB (N = 47) or WB (N = 50) group.WB (N = 50) group.
nn 1 year follow1 year follow--upup
nn Laxity, Laxity, LysholmLysholm and and TegnerTegner Scores, Scores, Knee Motion, Knee Motion, PatellofemoralPatellofemoral Pain, Pain, Satisfaction RatingSatisfaction Rating
Bynum BE, Barrack RL, Alexander AH. Open Vs Closed Chain Kinetic Exercises After ACL Reconstruction. Am J Sports Med. 1995;23:401-406.
SideSide--toto--Side jumping Side jumping against against SportcordSportcord
Unrestricted Quadriceps Unrestricted Quadriceps PRE’sPRE’s
12 weeks12 weeks
-- Knee bends, Leg PressKnee bends, Leg Press-- Hamstring curlsHamstring curls-- Low resistance cyclingLow resistance cycling-- ProprioceptiveProprioceptiveTraining?Training?-- Fwd/Fwd/BwdBwd walking walking against against -- SportcordSportcord-- Slow motion jogging Slow motion jogging against against SportcordSportcord
-- CocontractionCocontraction isomisom-- Low resistance leg extLow resistance leg ext-- Low resistance cyclingLow resistance cycling-- IsokineticIsokinetic hamstringshamstrings-- ProprioceptiveProprioceptiveTraining ?Training ?
00--8 weeks8 weeks
WBWBNWBNWB
Bynum BE, Barrack RL, Alexander AH. Open Vs Closed Chain Kinetic Exercises After ACL Reconstruction. Am J Sports Med. 1995;23:401-406.
-- Sport specific Sport specific exercises with exercises with SportcordSportcord
-- Treadmill joggingTreadmill jogging-- Fwd/Fwd/BwdBwd running, running, -- Single leg deep knee Single leg deep knee bendsbends
16 weeks16 weeks
-- Progressive running Progressive running and Sport specific and Sport specific trainingtraining
-- IsokineticIsokinetic quadsquads24 weeks24 weeks
-- Unrestricted ActivityUnrestricted Activity-- Unrestricted activityUnrestricted activity12 months12 months
-- NonNon--cutting, jumping, cutting, jumping, pivoting sportspivoting sports
-- NonNon--cutting, jumping, cutting, jumping, pivoting sportspivoting sports
9 months9 months
WBWBNWBNWB
Bynum BE, Barrack RL, Alexander AH. Open Vs Closed Chain Kinetic Exercises After ACL Reconstruction. Am J Sports Med. 1995;23:401-406.
Bynum BE, Barrack RL, Alexander AH. Open Vs Closed Chain Kinetic Exercises After ACL Reconstruction. Am J Sports Med. 1995;23:401-406.
Bynum BE, Barrack RL, Alexander AH. Open Vs Closed Chain Kinetic Exercises After ACL Reconstruction. Am J Sports Med. 1995;23:401-406.
nn Sooner than expected return to Sooner than expected return to ADLsADLs was only was only item on survey favoring WB training. Return to item on survey favoring WB training. Return to sport not different between groupssport not different between groups
nn Training programs, by design, not equivalent in Training programs, by design, not equivalent in progressing functional retraining. Progression progressing functional retraining. Progression favored WB. Might explain survey result.favored WB. Might explain survey result.
nn No difference in functional outcome measuresNo difference in functional outcome measures
nn Concluded there was more laxity in OKC group Concluded there was more laxity in OKC group but data did not indicate any real change in laxity but data did not indicate any real change in laxity from early rehab to 1 year. Variable subject from early rehab to 1 year. Variable subject numbers also minimize credibility of datanumbers also minimize credibility of data
Morrissey MC, Hudson ZL, Drechsler WI, et al. Effects of open Vs closed kinetic chain training on knee laxity in the early period after ACL reconstruction. Knee Surg, Sports Traumatol, Arthrosc. 2000;8:343-348.
nn 36 subjects, B36 subjects, B--PTPT--B B autograftautograftnn Randomly assigned to NWB or WB Randomly assigned to NWB or WB
groupgroupnn Groups differed in type of hip and knee Groups differed in type of hip and knee
strengthening exercisestrengthening exercisenn Laxity measured with Knee Signature Laxity measured with Knee Signature
System System arthrometerarthrometer after 4 weeks of after 4 weeks of trainingtraining
Morrissey MC, Hudson ZL, Drechsler WI, et al. Effects of open Vs closed kinetic chain training on knee laxity in the early period after ACL reconstruction. Knee Surg, Sports Traumatol, Arthrosc. 2000;8:343-348.
nn WB group: Leg Press, supine position, WB group: Leg Press, supine position, 9090°° to 0to 0°°, no description of load amount, no description of load amount
nn NWB group: Leg extensions, hip NWB group: Leg extensions, hip extensions, cuff extensions, cuff wghtswghts, machines, no , machines, no description of load amountsdescription of load amounts
nn Balance and Balance and proprioceptionproprioception in both in both groups, no description of the activitiesgroups, no description of the activities
nn Both groups allowed stationary cyclingBoth groups allowed stationary cycling
Morrissey MC, Hudson ZL, Drechsler WI, et al. Effects of open Vs closed kinetic chain training on knee laxity in the early period after ACL reconstruction. Knee Surg, Sports Traumatol, Arthrosc. 2000;8:343-348.
9.98mm9.98mm9.87mm9.87mmWBWB
10.25mm10.25mm9.46mm9.46mmNWBNWB
PostPostPrePre
Morrissey MC, Hudson ZL, Drechsler WI, et al. Effects of open Vs closed kinetic chain training on knee laxity in the early period after ACL reconstruction. Knee Surg, Sports Traumatol, Arthrosc. 2000;8:343-348.
nn No difference in laxity between groupsNo difference in laxity between groups
nn Not certain if intensity of exercise was Not certain if intensity of exercise was what is typically done in clinical practicewhat is typically done in clinical practice
nn Pain and Function scores not reported Pain and Function scores not reported in this studyin this study
nn Stated no difference in these variables, Stated no difference in these variables, cited other unpublished workcited other unpublished work
Mikkelsen C, Werner S, Eriksson E. Closed kinetic chain alone compared to combined open and closed kinetic chain exercises for quadriceps strengthening after ACL reconstruction with respect to return to sports: a prospective matched follow-up study. Knee Surg, Sports Traumatol, Arthrosc. 2000;8:337-342.
nn 44 subjects, B44 subjects, B--PTPT--B B autograftsautograftsnn Randomized to WB Vs WB+NWBRandomized to WB Vs WB+NWBnn Following randomization, matched Following randomization, matched
based on age, gender, activity levelbased on age, gender, activity levelnn Laxity with KTLaxity with KT--1000, 1000, isokineticisokinetic quad quad
and hamstring strengthand hamstring strengthnn Proportion of subjects returning to preProportion of subjects returning to pre--
injury activity levelinjury activity level
Mikkelsen C, Werner S, Eriksson E. Knee Surg, Sports Traumatol, Arthrosc. 2000;8:337-342.
Mikkelsen C, Werner S, Eriksson E. Knee Surg, Sports Traumatol, Arthrosc. 2000;8:337-342.
nn WB + NWB groupWB + NWB groupuu isokineticisokinetic concentric/eccentric leg concentric/eccentric leg
extensions, 90extensions, 90°°--4545°°, initiated 6 weeks , initiated 6 weeks following surgeryfollowing surgery
uu progress to progress to 9090°°--1010°° over 6 week periodover 6 week period
Mikkelsen C, Werner S, Eriksson E. Knee Surg, Sports Traumatol, Arthrosc. 2000;8:337-342.
Mikkelsen C, Werner S, Eriksson E. Knee Surg, Sports Traumatol, Arthrosc. 2000;8:337-342.
79.579.569.869.8EccEcc: 120/sec: 120/sec
79.779.772.272.2Con: 120/secCon: 120/sec
83.283.265.765.7EccEcc: 30/sec: 30/sec
78.878.865.765.7Con: 30/secCon: 30/sec
WB + NWBWB + NWBWBWB
Quadriceps Strength Index (% of uninvolved Quadriceps Strength Index (% of uninvolved limb), 6 months postlimb), 6 months post--opop
Mikkelsen C, Werner S, Eriksson E. Knee Surg, Sports Traumatol, Arthrosc. 2000;8:337-342.
10101212
(7.5 months)(7.5 months)
WB + NWBWB + NWB
171755
(9.5 months)(9.5 months)
WBWB
NoNoYesYes
Number of Subjects Returning to PreNumber of Subjects Returning to Pre--injury injury Level of Sports ActivityLevel of Sports Activity
X2 test significant, p < .05, NNT = 3
Summary of RCT’s
nn Adding NWB exercises do not appear to increase Adding NWB exercises do not appear to increase laxity or cause injurylaxity or cause injuryuu Manner in which NWB exercise is applied may Manner in which NWB exercise is applied may
be a factor (delay aggressive resistance, use be a factor (delay aggressive resistance, use protected ranges)protected ranges)
nn Two studies do not report differences in outcome Two studies do not report differences in outcome measures between groupsmeasures between groups
nn MikkelsenMikkelsen indicates that adding NWB resistance indicates that adding NWB resistance training in a controlled manner to a well rounded training in a controlled manner to a well rounded WB and functional retraining program can improve WB and functional retraining program can improve quad strength and return to prequad strength and return to pre--injury sports injury sports activity without increasing laxityactivity without increasing laxity