HAMSTRING INJURY
The accuracy of MRI in predicting recovery and
recurrence of hamstring muscle strains
Dr N Gibbs Dr T Cross Mr M Cameron Dr M Houang
J Sci Med Sport. 2004 Jun
1. Introduction
2. Literature review
3. Methods
4. Results and Discussion
5. Conclusions
6. Questions??
Clinical Scenario
e.g.. Posterior thigh pain 7 days before World Cup Final
Can he play??
1. Introduction
Objective
1. To describe the MRI findings of a series of acute hamstring muscle strains (i.e. “posterior thigh pain”)
2. Do these MRI findings help
1. Predict the PROGNOSIS
2. Predict The RECURRENCE RATE
Setting
Sydney Swans Football Club
1 of 16 clubs
in the National competition
Design
Prospective study over 5 years (1999-2003):
Both in-season and pre-season periods
Patients
40 professional footballers
Consent from Club and individual players
Australian Rules Football
“Athletes at risk”
Repetitive sprinting efforts Repetitive kicking Repetitive jumping &
landing Game time approximately
100 minutes
Australian Rules Football
Ideal sport ( “outdoor laboratory”) to study muscle strain injury
Australian Rules Football
Hamstring strain is the most significant injury in ARF
(Quadriceps strain in top 10)
Motivation for research
To better understand/diagnose Hamstring muscle strains
To better manage/rehabilitate Hamstring muscle strains
Motivation for research
To make an EARLY ACCURATE PROGNOSIS
(i.e. we were unable to clinically differentiate benign from serious Hamstring strains)
Motivation for research
To better understand which “hamstring” injuries recur
2. Literature Review
Anatomy
Hamstrings, an “at-risk muscle”
Acts eccentrically
Crosses two joints
High % fast twitch fibres
Function
Main Function during sprintingAnd kicking is to deceleration of knee extension and hip flexion
AFL injury database
Cause 20% of all missed AFL games
Recurrence rate 34%
Literature review
Pomeranz (1993)
• Retrospective study of Hamstring strains
• n=14
• Prognosis associated with size (cross-sectional area%) of muscle strain injury on MRI scan
3. Methods
Methods
Inclusion criteria
1. History
acute onset of posterior thigh pain/ache or tightness while training or playing
2. Examination : tenderness over the posterior thigh: other signs elicited but not the subject of this study
Methods
Exclusion criteria
1. History of trauma to posterior thigh (Contusion)
2. Delayed onset of posterior thigh pain (DOMS)
3. Recurrence of posterior thigh pain in ipsilateral thigh in same season
Methods
MRI within 24-72 hours
• T1,T2 with fat suppression, STIR
• Axial, coronal planes (both thighs imaged)
(Axial T2 with fat suppression most useful images)
Methods
Muscle strain injury= high signal on T2 weighted images
Methods
MRI diagnosis
Location (MRI category)
1. Which Hamstring muscle (s) injured
2. Location of injury with respect to known musculotendinous junctions
Methods
MRI diagnosis
Size
1. Cross sectional area % (CSA)
2. Length (cm)
Methods
CSA% estimation (“dot” method)
Estimation of Length
Methods
MRI diagnosis: miscellaneous features…
• T2 hyper intensity
• muscle fibre disruption
• Perifascial fluid
• Scarring/fibrosis
Methods
What if more than one muscle injured? (i.e. double injury etc.)
1. Primary muscle injured= greatest CSA%
2. Secondary muscle injury= smaller CSA%
Methods (rehabilitation phase)
No universally accepted rehabilitation regimen exists for muscle strain injuries
Methods (rehabilitation phase)
Rehabilitation was standardised
Phase 1 : Acute management
RICE/crutches first 48 hours
Intensive Physiotherapy
• soft tissue therapy• flexibility• strengthening
Methods (rehabilitation phase)
Phase 2: Remodeling phase
Eligible to start running program when,
Full pain free ROM
Complete 3 x 10 repetitions of single leg hops pain free
4 Stage running/kicking program (sport specific to ARF) was designed at beginning of study
Methods (rehabilitation phase)
4 stage running/kicking program
Run alternate days Physiotherapist/Sports Scientist supervision Combined with intensive physiotherapy
5 minute jog warm up/cool down
Stage 1 : jog 10 mins x 2
Stage 2 : 80m intervals ( 40-60 %) 3x 5 repetitions
Stage 3: 80m intervals (90-100%) 3 x 5 repetitions (staged kicking program commenced)
Stage 4: 80m intervals (sport specific drills at 90-100%) 3 x 5 repetitions
Integrate into team training
Methods (rehabilitation phase)
4 stage running/kicking programs
• Some advanced rapidly
• Others delayed by symptoms of high grade posterior thigh pain, weakness and dysfunction
Decision to return to Full Training : Collaborative
Rehabilitation interval (RI)
RI= time from the injury to the return to full training (measured in days)
2. Results and Discussion
Results of acute MRI images
31 acute clinical HAMSTRING strains were imaged
Authors were not blinded to these MRI’s
Clinical Hamstring strains“Posterior thigh pain”
N=31
MRI positiveN=1755%
MRI negativeN=1445%
Single muscleN=12
Double musclen=5
All involving BF as primary injury
Biceps femorisN=8
ST and SMN=2 each
Recurrent hamstring injury
Of the 17 MRI positive cases (“hamstring muscle strains”)
N= 6 recurred within same season!!
35% recurrence rate
Size of muscle strain injury (length &/or CSA%) did NOT predict risk of recurrence
Recurrent hamstring injury
Of the 14 MRI negative cases
None recurred within same season!!
0 % recurrence rate
Statistical analysis
Statistician analyzed data
t-tests independent samples (dependent vs. independent variables)
Two-way analysis of variance
Results: Statistical analysis
02468
101214161820
MRI Diagnosis
MRIpositive(mean=20,range 12-33 days )MRI negative (mean6.6, range 2-12)
RI
(days)
MRIPositive
MRINegative
MRI Positive
n=17
Mean RI=20.2 days
significantly longer RI (p=0.001)
Results: Statistical analysis
0
5
10
15
20
25
30
MRI Diagnosis
Length > 12cmLength 7-12 cmLength < 7cm
RI
(days)
MRI & Prognosis
Length of intra-muscular signal correlates best with RI r=0.84, p<0.001
CSA% & RI r=0.78
Size really does matter
0
5
10
15
20
25
0 10 20 30 40
Rehab Interval (days)
leng
th (c
m)
MRI negative cases
n=14
Mean RI= 6.6 days (benign injury)
MRI negative cases
Hypotheses
MRI done too early
Strain injury too small to resolve
Other causes of “Posterior thigh pain”
Other causes of posterior thigh pain
Somatic Referred pain
Lumbosacral spine Pelvis
Other causes of posterior thigh pain
Neuromeningeal tethering
Nerve root ( “radiculopathy”)
Piriformis syndrome Hamstring syndrome Within HS muscles
Other causes of posterior thigh pain
Intrinsic Muscle causes
Tender points Trigger points Adhesions/fibrosis/
scarring Tendinopathy/bursitis
Other causes of posterior thigh pain
“Not to be missed”
Avulsion Fractures Complete rupture proximal
HS Stress Fractures Compartment syndromes Tumours (benign and
malignant) Infections (bone/soft
tissue) Rheumatologic
CONCLUSIONS
Conclusions
MRI defines muscle strain injury objectively:
“probe beneath the surface of the skin”
Conclusions
Posterior Thigh Pain
MRI Positive“Hamstring strain injury
MRI NegativeNumerous other DDx’s
Somatic referredNeuromeningeal
Etc.
Conclusions
All 17 MRI positive cases of muscle strain injury occurred about known muscle-tendon junctions
(This concurs with basic science studies)
Conclusions
The Biceps femoris was the most commonly injured muscle (8 single, 5 “double” injuries)
Conclusions
Tenderness over the posterior thigh does not always = muscle strain injury
Concept of “MRI NEGATIVE” diagnosis
Conclusions
02468
101214161820
MRI Diagnosis
MRIpositive(mean=20,range 12-33 days )MRI negative (mean6.6, range 2-12)
RI
(days)
MRIPositive
MRINegative
Conclusions
Size ( LENGTH and CSA%) of muscle strain injury is also predictive of RI
0
5
10
15
20
25
30
MRI Diagnosis
Length > 12cmLength 7-12 cmLength < 7cm
Conclusions
Indications for MRI
Acute MRI for elite athletes
Soccer World Cup 2002
e.g. Posterior thigh pain 7 days before Final
Can he play??
YES : if MRI negative
NO: if MRI positive
Conclusions
If no MRI available? Suspect MRI positive if troubled by high grade posterior thigh pain in rehabilitation
Indications for MRI
Thank-you
Questions?
MRI findings determine type & pace of rehab
Positive vs Negative Entirely different
management Length
Predict return to play Set stages of rehab
Other markers Tendon involvement Fluid around sciatic
n.
REHABILITATION Promote healing
Regeneration > Scarring Restore flexibility of injured region
Prevent shortening Common finding in retrospective studies
Restore strength of hamstring group Retraining of hip extension & knee flexion Prevent shortening of angle of peak torque Brockett et al 2002
More prone to damage with eccentric ex Due to injury or rehab or inherent
Running Re-Training Correct contributing factors if possible
RUNNING RETRAINING
Formalised by G. Reid – Hockey background Allows return to competitive sport prior to complete healing of
injury site Involves:
Running early – when stair walking pain-free Running is progressed in stages of speed increments Jog then Fartlek Running 90m intervals EZ
5 stages till sprinting Controlled sport specific drills prior to returning to training
Possible mechanism
Retraining of muscles responsible for the hip extensor & knee flexor torque during running
BF-S & L, ST, SM, Glut, AM, Gastroc Change in relative contribution of each muscle Any change in recruitment yet to be determined Sufficient slack in the system
Inhibit the injured muscle Facilitate remaining muscles
Observations1. Large single hamstring strains exhibit obvious inhibition
Lower resting tone on palpation Poor recruitment during isometric contraction
2. Double hamstring muscle strains 14 BF & ST injuries – 9 recurred within rehab or within
12/12 64% recurrence rate – double the norm May reflect an inability of the system to adequately
compensate for the injured muscle
Role of dual channel biofeedback Early or later stages of rehab
Similar effect as suggested by Sherry & Best
Sherry & Best 2004 JOSPT
RCT of 2 programmes 24 grade 1-2 hamstring injuries Stretch & Strength (11)
Stat bike, static & C-R stretches, isometric to conc to ecc strength X’s with cuff wts, T/B & BW
Progressive Agility & Trunk Stabilisation (13) Sidestepping, grapevines, fwd & bwd steps while
sidestepping, balance exercises, jogging on spot, trunk stabilisation X’s
Progressive intensity
Both programmes involved sport practice when pain- free
Sherry & Best 2004 JOSPT
STST - mean RTS 37.4 days (10-95, sd 27.6)
PATS - mean RTS 22.2 days (10-35, sd 8.3)
p=0.2455
Recurrence rates STST 54.5% at 2 wks, 70% at 1yr PATS 0% at 2 wks, 7.7% at 1 yr p=0.003
Allows regeneration > scar Better prevention of atrophy Better trunk stability, co-ordination or motor control
Contributing Factors
Strength L/R balance, H/Q balanceBurkett 1970, Yamamoto 1993, Orchard et
al 1997, Cameron et al 2003 Inadequate strength for function required
Eg. Running & bending or jumping Determine mechanism
Specific Flexibility Bennell et al 2003 Ankle Dorsiflexion < 10cm p=0.036 Hip Flexors – MTT > 0degs p=0.051
Contributing Factors Other injuries and Gluteal Function
Previous calf injury Orchard 2001 Previous knee injury or osteitis pubis Verrall et al 2001
Altered biomechanical factors - inherent or due to injury Ankle sprain ↓ glut function Bullock-Saxton et al 1994
Poor lower limb motor control Cameron et al 2003
Summary – Hammy Rehab
Diagnosis Muscle strain or posterior thigh pain (PTP)
MRI & clinical testing Extent of strain injury - MRI
Re-training Programme
Pre-disposing factors