Bone stress injuries Flashcards
Epidemiology
Difficult diagnosis- mimic other overuse injury + not often findings on x-ray
Majority of sports overuse injuries in track and field
20-60% incidence
Main 3 locations for overuse bone stress injuries
tibia
metatarsals
navicular
State the locations of the low risk bone stress injuries
LOW RISK
- posteromedial border of tibia
- femur
- 1-4th metatarsals
- ribs
- ulnar
State the locations of the high risk bone stress injuries
HIGH RISK
- anterior edge of tibia
- neck of femur
- navicular
- 5th metatarsal
What are the issues associated with high risk bone stress injuries?
- Delayed diagnosis
- Delayed Tx
Leading to:
- increased healing time
- non-union
- surgery
Role of Hx in BSI Dx
- Sport
- Event
- Training intensity
- Previous BSI
What specific questions should you ask about symptoms for a bone stress injury?
- exercise related
- progressively worse
- intermediate
- night pain
How are BSIs graded according to Sx frequency?
Grade 1: end of training
Grade 2: mid-training
Grade 3: whole training
Grade 4: Daily ctivities
What clinical tests are used for LL BSI
- one leg hop test
DDx for BSI
- bone contusion
- osteomyelitis
- neoplasm (lymphoma, leukaemia)
First line investigation for suspected BSI
Therapeutic USS
Most symptomatic point spotted at 2w/cm2 and decreased if painful by 0.1w/cm
80% sensitivity and 67% specificity
Second line Investigations for BSI
If therapeutic USS is positive –> MRI
If therapeutic USS negative –> x-ray
Gold standard investigation for bone stress injuries
MRI
Sensitive and specific, can be used to grade
MRI BSI grading system
Grade 0 = normal Grade 1 = endosteal marrow oedema Grade 2 = periosteal and endosteal marrow oedema Grade 3= Grade 2 and soft tissue oedema Grade 4 = fracture line
What grade of BSI does the following MRI show
Grade 1: endosteal marrow oedema
What grade of BSI does the following MRI show
endoteal and periosteal marrow oedema
What grade of BSI does the following MRI show?
Grade 3- endosteal, periosteal and soft tissue oedema
What grade of BSI does the following MRI show?
Grade 4: stress fracture
Main objective assessment tool in the diagnosis of BSI
Diagnostic imaging
Limitations of radiographs for BSI
often appear normal despite clinical Sx and signs suggestive of BSI
what are the benefits and negatives of radioisotope bone scanning in diagnosis of BSI?
very high sensitivity 84-100%
HOWEVER:
- low specificity (high false positive)
- high radiation dose
How does diagnosis and severity of BSI correlate with regards to Sx onset?
Mx of BSI
- Majority is conservative
- Modify training- not rest
- Medication
- Physio modalities
- Rehabilitation + dealing with predisposing factors
Extrinsic risk factors for BSI
mileage
number of training cycles
inadequate recovery periods and training fatigued muscles
pace
downhill running
sports- track, basketball, gymnastics, running
harder running surface
Intrinsic risk factors for BSI
External rotation of LL
Bony anatomy: leg length discrepancy, femoral anteversion, genu varum/valgum, narrow tibia
Muscle- small calf girth
Female Nutrition- low calcium/vit D, calorie deficit Older age >20 aerobic fitness + sporting experience Previous BSI Smoking FHx
Phase 1 Mx BSI- Grade 1-3
- control pain
- NWB- swimming, core, stability
- Local Tx- low intensity pulsed TUS
TILL AT LEAST ONE WEEK WITHOUT PAIN WALKING
Phase 2 Mx BSI- Grade 1-3
Training modification:
- local Tx- low intensity pulsed TUS- EWST
- cycling, XT, stair stepper
- deal with modifiable RF
Phase 3 Mx BSI- Grade 1-3
Functional- RTP
- Functional rehab
- Sport specific
- 10% increase every 10 days
aim to be free of symptoms on therapeutic USS
Which stress fractures are low risk of non-union?
- Femoral neck fractures of medial cortex
- Tibial shaft fractures of the posteromedial cortex
- distal 2-4 metatarsals
- calcaneal fractures
- fractures of fibula
- fractures of pubic ramus
Mx low risk stress fractures
conservative management
increase impact loading once ambulation and dat to day activity are pain free
treat underlying RF and modify training regimen
Which stress fractures are at high risk of non-union?
- femoral neck
- tibial shaft anterior cortex
- navicular
- talus/medial malleolus/sesamoids
How are stress fractures with high risk managed?
- often require operative management
- risk of non-union or delayed union
What grade BSI does this MRI show and what is the Mx?
Grade 3 BSI
fracture of navicular bone
Start conservative: non-weight bearing cast 6 weeks, then depends on pain- 86% rate of healing + boot
If this fails, surgical Mx
Sx femoral stress fractures
pain in anterior inguineal area
How are femoral stress fractures diagnosed?
70% with the hop test
How are femoral stress fractures managed?
Compression-type fractures: conservative (RTP 8-16wks)
Tension-type fractures/displaced: internal fixation
Mx of metatarsal fractures
2nd-4th:
- 20% all lower extremity BSF
- 4-6wks limited activities or casting 4-6wks
5th:
- 6-8wks non-weight bearing cast
- 70% healing without surgical fixation
what is the highest demographic affected by tibial stress fractures
40-50% in athletes
Mx tibial stress fractures
Can be posteromedial or anterior
1) conservative (ant)
2) aircast splinting if more severe Sx /not resolved conservatively
3) casting for mid-shaft fracture until pain free and radiographic evidence of healing
4) Surgery (intramedullary nailing +/- grafting) if no improvement after 6 months
BSI grade and time to RTP
Grade 1: 3-4 weeks
Grade 2: 5-8 weeks
Grade 3: 9-16 weeks
Grade 4: 16+ weeks
prophylaxis BSI
training is key prevention
- periodisation- inc training over 3 weeks and follow with 1 week relative rest, allowing met adaptation
- monitor loading and intensity
- deal with modifiable RF
- optimal nutriotion calcium vit D
Summary BSI points
