Quadriceps Muscle Injuries:Quadriceps Muscle Injuries:An OverviewAn Overview

William E Garrett, MD, PhDWilliam E Garrett, MD, PhDDuke University Medical CenterDuke University Medical Center

IntroductionIntroduction

Muscle injuries are a major cause of Muscle injuries are a major cause of time lost to sporttime lost to sport

Yet they have received the least Yet they have received the least attention from research and clinical attention from research and clinical investigationinvestigation

Muscle Injury EpidemiologyMuscle Injury Epidemiology

Professional Football (Soccer)Professional Football (Soccer)•UEFA study of 51 teams /2299players/ 9yearsUEFA study of 51 teams /2299players/ 9years•Players averaged 0.6 injury/ yearPlayers averaged 0.6 injury/ year•31% of all injuries31% of all injuries•27% of missed time27% of missed time

Ekstrand et al., AJSM, 2011

Muscle Injury EpidemiologyMuscle Injury Epidemiology

92% of injuries affected 4 muscle groups92% of injuries affected 4 muscle groupsHamstrings 37%Adductors 23%Quadriceps 19%Calf 13%

Ekstrand et al., AJSM, 2011

Muscle Strain InjuriesMuscle Strain Injuries

Quadriceps muscle injuries in professional Quadriceps muscle injuries in professional soccer cause more time lost than any other soccer cause more time lost than any other

muscle injury (Ekstrand 2011)muscle injury (Ekstrand 2011)

Mechanism of InjuryMechanism of Injury• Indirect traumaIndirect trauma• Stretch is required with or without activation.Stretch is required with or without activation.• These injuries usually involve high speed athletic activities with eccentric These injuries usually involve high speed athletic activities with eccentric

contraction:contraction:–SprintingSprinting–KickingKicking

Mechanism of InjuryMechanism of Injury

• Experimental animal studies (Garrett et al.):Experimental animal studies (Garrett et al.):– Muscle maximally tetanically stimulated Muscle maximally tetanically stimulated lose force lose force

but no structural damage observed (force loss due to but no structural damage observed (force loss due to nerve injury?)nerve injury?)

– Role of stretching: 2 groups Role of stretching: 2 groups stretch + activation vs stretch + activation vs stretch alone:stretch alone:• Both injured with same amount of stretchBoth injured with same amount of stretch• Activated muscles that failed had only 15% more force at Activated muscles that failed had only 15% more force at

time of complete disruption.time of complete disruption.• Activated muscles absorbed more energyActivated muscles absorbed more energy

(strength)

(flexibility)

Mechanism of injuryMechanism of injury

Mechanism of injury:Mechanism of injury:Effect of Muscle Activation During StretchEffect of Muscle Activation During Stretch

Length-Tension Deformation

Force

Length

Greater Force of ContractionGreater Force of Contraction

More Energy Absorbed More Energy Absorbed Prior to FailurePrior to Failure

Implications for strength Implications for strength and fatigue effectsand fatigue effects

Mechanism of injuryMechanism of injury

Mechanism of InjuryMechanism of Injury• Stronger muscle (eccentriccally stretched) Stronger muscle (eccentriccally stretched)

absorb more energy before length for injury.absorb more energy before length for injury.• Flexible muscles Flexible muscles stretch further before stretch further before

injury point.injury point.• Flexible muscles Flexible muscles allow active muscle allow active muscle

forces to decelerate the joint before forces to decelerate the joint before excessive stretchingexcessive stretching

Mechanism of InjuryMechanism of Injury Injured muscles are:Injured muscles are:– Those that are slowing down or stopping motionThose that are slowing down or stopping motion– Activated or contractingActivated or contracting– Being lengthened Being lengthened

Implications:

–Flexibility: ability of muscle to be stretched without injury risk factor/preventive role

–Strenght: ability to absorb load while stretching risk factor/preventive role

Histological studiesHistological studiesThe tendon is not injured.The tendon is not injured. The muscle tearsThe muscle tears• Within the muscle fibersWithin the muscle fibers• Near the muscle-tendon Near the muscle-tendon

junction junction • Often small amount of muscle Often small amount of muscle

fiber still attached to the tendonfiber still attached to the tendon

Pathological ChangesPathological Changes

Regardless of muscle Regardless of muscle fiber architecturefiber architecture

Histological studiesHistological studies• Entire muscle fiber does not dieEntire muscle fiber does not die• Its membrane is sealed over near the point Its membrane is sealed over near the point

of rupture.of rupture.• Muscle stretched to beyond ultimate failure Muscle stretched to beyond ultimate failure

very short fibers left at the tendon portion very short fibers left at the tendon portion• Muscle mildly stretched Muscle mildly stretched only a few fibers only a few fibers

torn at the muscle/tendon junctiontorn at the muscle/tendon junction

Histological studiesHistological studies

• Injury usually occur at the proximal or distal Injury usually occur at the proximal or distal end of the muscle/tendon junctionend of the muscle/tendon junction

• Muscle fibers do not seem to tear away from Muscle fibers do not seem to tear away from the proximal or distal endsthe proximal or distal ends

Histological studiesHistological studies

• Damage near muscle/tendon junction Damage near muscle/tendon junction actually predicts failure at a lower amount of actually predicts failure at a lower amount of strain.strain.

• Small injuries Small injuries muscle at more risk for muscle at more risk for major injurymajor injury

• Small injuries Small injuries predict larger injuries predict larger injuries (previous injury as risk factor)(previous injury as risk factor)

Histological studiesHistological studies

• Incomplete or non-Incomplete or non-disruptive injuries (small disruptive injuries (small strains):strains):– TThe muscle is torn he muscle is torn

enough to be enough to be histologically abnormal histologically abnormal and be able to generate and be able to generate less forceless force

acute

Initial bleeding + inflammatory cells

Histological studiesHistological studies

48 hr7d

Macrophages and other inflammatory cells to debride the damaged tissue

Connective tissue reconnects the muscle fibers to the tendon

Recovery Following Non-Disruptive Injury Recovery Following Non-Disruptive Injury

Recovery of Recovery of contractile contractile function in function in

approximately approximately one weekone week

(rabbit model)(rabbit model) 0102030405060708090

100

0 hrs. 24 hrs. 48 hrs 7 days

Time After InjuryTime After Injury

Force Generation % of ControlForce Generation % of Control

70.570.5

51.151.1

74.574.592.592.5

Histological studiesHistological studies

Rectus Femoris InjuriesRectus Femoris Injuries• Rectus femoris injury is probably more Rectus femoris injury is probably more

common than is generally reportedcommon than is generally reported• The most common of quadriceps musclesThe most common of quadriceps muscles• BiarticularBiarticular• Stretched with hip extension and knee Stretched with hip extension and knee

flexion (kicking sports at start of accelerated flexion (kicking sports at start of accelerated hip flexion and knee extension).hip flexion and knee extension).

AnatomyAnatomy• Direct head:Direct head:

– AIISAIIS– Spreads out over the anterior surface of the muscleSpreads out over the anterior surface of the muscle

• Indirect head:Indirect head:– Edge of acetabulum and superior hip capsule.Edge of acetabulum and superior hip capsule.– Forms a tendon within the larger rectus femoris.Forms a tendon within the larger rectus femoris.– Muscle/tendon junctions arising from indirect head Muscle/tendon junctions arising from indirect head

often covered by muscle fibers arising from direct often covered by muscle fibers arising from direct head.head.

– Looks like a muscle strain in the middle of muscleLooks like a muscle strain in the middle of muscle– Bull’s eye sign = muscle tear around central tendonBull’s eye sign = muscle tear around central tendon

AnatomyAnatomy• Direct head:Direct head:

– AIISAIIS– Spreads out over the anterior surface of the muscleSpreads out over the anterior surface of the muscle

• Indirect head:Indirect head:– Edge of acetabulum and superior hip capsule.Edge of acetabulum and superior hip capsule.– Forms a tendon within the larger rectus femoris.Forms a tendon within the larger rectus femoris.– Muscle/tendon junctions arising from indirect head Muscle/tendon junctions arising from indirect head

often covered by muscle fibers arising from direct often covered by muscle fibers arising from direct head.head.

– Looks like a muscle strain in the middle of muscleLooks like a muscle strain in the middle of muscle– Bull’s eye sign = muscle tear around central tendonBull’s eye sign = muscle tear around central tendon

ANATOMY

DIRECTDIRECT

INDIRECTINDIRECT ****

**

**

**

ANT APONANT APON

INTRA MUSINTRA MUSTENDONTENDON

II DD

DEEPDEEP

AJSM23,4’95AJSM23,4’95

A MUSCLE WITHIN A MUSCLEA MUSCLE WITHIN A MUSCLE

Clinical presentationClinical presentation–pain in anterior thigh after high speed, pain in anterior thigh after high speed,

high force muscle actionhigh force muscle action–initial painful swellinginitial painful swelling–subsequent bulge with muscle activationsubsequent bulge with muscle activation–appearance of ruptured muscle-tendon appearance of ruptured muscle-tendon

unitunit

Clinical courseClinical course–prolonged improvementprolonged improvement–often near-complete recoveryoften near-complete recovery–some have persisting pain and asymmetrysome have persisting pain and asymmetry–some have question of a neoplasmsome have question of a neoplasm–Initially considered to be distal MTJ injuries Initially considered to be distal MTJ injuries

often avulsions due to mass effect “Popeye”often avulsions due to mass effect “Popeye”

MRIMRI

–high T2 signal in rectus femorishigh T2 signal in rectus femoris–only a portion of muscle involvedonly a portion of muscle involved–central portion of muscle is most central portion of muscle is most

involvedinvolved

TreatmentTreatment

–out of many injuries, very few out of many injuries, very few surgeriessurgeries

–symptoms are usually tolerable symptoms are usually tolerable without surgerywithout surgery

–a significant incisiona significant incision

TreatmentTreatment

Make every effort to treat these Make every effort to treat these conservativelyconservatively

Surgery is not easy or intuitiveSurgery is not easy or intuitive

SummarySummary–occur in high intensity and velocity occur in high intensity and velocity

situations: stretching +/- activation situations: stretching +/- activation (sprinting or kicking)(sprinting or kicking)

–almost always activated eccentricallyalmost always activated eccentrically–occur at muscle-tendon junctionoccur at muscle-tendon junction–conservative treatmentconservative treatment– flexibility/strength should help preventionflexibility/strength should help prevention