01Approach to the Critical Patient/attcp49

Triage and immediate threats

›High-risk stress injury screen

›Unbearable pain at rest or night pain

›Rapidly worsening pain over hours to days

›Inability to bear weight for 4 steps

›Visible deformity or acute swelling after a specific injury

›Fever or systemic symptoms

›New neurologic deficit

›Cool, pale foot or diminished distal pulses

›Severe pain out of proportion to exam

Limb threat priorities

›Neurovascular status

›Dorsalis pedis pulse

›Posterior tibial pulse

›Capillary refill time

›Foot temperature and color

›Peroneal nerve motor

›Ankle dorsiflexion

›Great toe extension

›Tibial nerve motor

›Ankle plantarflexion

›Toe flexion

›Sensation

›Dorsum of foot

›Plantar foot

›Doppler signal if pulses equivocal

›Compartment syndrome pathway

›Key features

02History/hx61

Symptom and training timeline

›Timeline and progression

›Onset date

›Gradual onset with activity

›Pain at start of run then improves

›Pain that persists after activity

›Pain at rest or night pain

›Training load

›Recent mileage increase

›Change in intensity or terrain

›New shoes or worn shoes

›Running on cambered surfaces

›Recent marching or military training

›Functional limitation

›Ability to bear weight

›Ability to hop on affected leg

›Gait change or limp

Injury and co-injury context

›Specific trauma alternative

›Twist, fall, direct blow

›Audible crack or sudden pain

›Location specificity

›Posteromedial tibial pain

›Anterior tibial pain

›Fibular lateral pain

›Distal third fibula pain

›Prior fractures

›Prior tibial stress fracture

03Physical Exam/exam41

Focused lower leg exam

›Localization

›Point tenderness over tibial cortex

›Point tenderness over fibula

›Diffuse posteromedial tibial tenderness

›Palpable bony swelling

›Functional testing

›Hop test pain

›Single-leg heel raise pain

›Gait assessment

›Skin and soft tissue

›Swelling extent

›Ecchymosis pattern

›Erythema warmth

›Wound or ulcer

Joint above and below

›Knee

›Effusion

›Ligament stability if trauma history

›Ankle

›Lateral malleolus tenderness

›Syndesmosis pain

›Peroneal tendon tenderness

Neurovascular and compartment exam

›Distal perfusion

›Dorsalis pedis pulse

›Posterior tibial pulse

›Cap refill

04Differential Diagnosis/ddx41

Primary and common mimics

›Stress fracture of tibia

›ICD-10 M84.36

›SNOMED CT concept stress fracture of tibia

›Stress fracture of fibula

›ICD-10 M84.37

›SNOMED CT concept stress fracture of fibula

›Medial tibial stress syndrome

›ICD-10 M76.80

›Chronic exertional compartment syndrome

›ICD-10 M79.A

›Periostitis

›ICD-10 M86.8

›Tendinopathy

›Peroneal tendinopathy

›Posterior tibial tendinopathy

›Muscle strain

›Soleus strain

›Tibialis anterior strain

High-stakes alternatives

›Acute tibial fracture

›ICD-10 S82.20

›Acute fibular fracture

›ICD-10 S82.40

›Osteomyelitis

›ICD-10 M86.1

›Bone tumor or pathologic fracture

›ICD-10 M84.5

05Laboratory Tests/lt28

Low-risk typical presentation

›Minimal lab strategy

›No routine labs in uncomplicated, afebrile, low-risk stress fracture

›Pregnancy test if imaging with ionizing radiation and pregnancy possible

Infection or inflammatory concern

›Infection screen

›CBC for fever or systemic symptoms

›Leukocytosis supports infection but nonspecific

›CRP for osteomyelitis concern

›Elevated CRP supports inflammatory or infectious process

›ESR for osteomyelitis concern

›Elevated ESR supports inflammatory or infectious process

Metabolic bone risk evaluation

›Bone health labs when recurrent, high-risk, or delayed healing

›25-OH vitamin D

›Deficiency risk for stress injury recurrence

›Calcium

›Hypocalcemia suggests endocrine or nutritional issues

›Phosphate

›Low phosphate suggests osteomalacia risk

›PTH

›Elevated PTH suggests secondary hyperparathyroidism

›TSH

›Hyperthyroidism increases bone turnover risk

›Ferritin if low energy availability suspected

›Low ferritin supports under-fueling risk pattern

Rhabdomyolysis or crush concern

›Muscle injury screen

06Diagnostic Tests/dt59

Scoring Systems

›MRI-based tibial stress injury grading

›Fredericson grading concept

›Grade 1

›Periosteal edema on T2

›Normal T1

›Grade 2

›Periosteal edema

›Marrow edema on T2

›Normal T1

›Grade 3

›Periosteal edema

›Marrow edema on T2

›Marrow edema on T1

›Grade 4

›Fracture line present

›Extensive marrow edema

›Prognostic use

›Higher grade associated with longer return-to-run time

›Fracture line supports high-risk management pathway

Radiographs

›Plain radiograph strategy

›Views

›Tibia-fibula AP and lateral

›Include knee joint

›Include ankle joint

›Expected yield

›Early sensitivity low

07Disposition/dispo34

Risk stratification

›Low-risk stress fracture disposition

›Posteromedial tibial cortex pattern

›Fibular shaft pattern without fracture line progression

›Intact neurovascular exam

›Pain controlled with oral meds

›Safe mobility with crutches if needed

›High-risk stress fracture disposition

›Anterior tibial cortex pattern

›Stress fracture with visible fracture line

›Recurrent stress fracture at same site

›Suspected complete fracture progression

›High-risk patient factors

›Eating disorder risk

›Severe vitamin D deficiency risk

›Osteoporosis risk

Discharge criteria

›Safe outpatient plan

›Reliable follow-up within 1 week

›Clear weight-bearing instructions

›Return precautions reviewed

›Immobilization plan in place when indicated

Admission or transfer criteria

›Admission triggers

›Uncontrolled pain despite ED regimen

›Inability to ambulate safely despite aids

›Concern for compartment syndrome

›Suspected pathologic fracture needing urgent workup

08Treatment/t81

Immediate life-saving interventions

›Limb-threatening complication response

›If compartment syndrome suspected, immediate ortho consult

›If pulseless or cool foot, immediate vascular evaluation and transfer

›If systemic infection concern, sepsis pathway and imaging for osteomyelitis

Immobilization and Splinting

›Immobilization approach

›Low-risk tibial or fibular stress fracture

›Activity modification without rigid immobilization when tolerated

›Walking boot if pain with walking

›High-risk tibial stress fracture

›Walking boot

›Non-weight-bearing until specialist assessment

›Splint options

›Posterior short leg

›Posterior long leg when knee involvement or severe pain

›Knee immobilizer when proximal tibial pain pattern with guarding

›Principles

›Swelling-phase avoidance of circumferential casting

›Neurovascular reassessment after immobilization

Reduction

›Reduction not typical for stress fracture

›If acute displaced fracture identified, fracture reduction pathway

›If deformity present, treat as acute fracture until proven otherwise

Open fracture medications and timing

›Open fracture pathway not typical for stress fracture

›If skin breach overlying bone, open fracture protocol

›Cefazolin IV within 60 minutes if feasible

›Tetanus prophylaxis per immunization status

›Urgent ortho consult

DVT prophylaxis when relevant

›Immobilization thrombosis risk assessment

›Risk factors

›Prior VTE

›Active malignancy

›Estrogen therapy

›Major immobility

›Recent surgery

›If high VTE risk and lower limb immobilization, follow local prophylaxis protocol

›If low VTE risk, routine pharmacologic prophylaxis often not indicated

Analgesia and symptom control

›Pain regimen

›Acetaminophen

›1000 mg PO every 6 to 8 hours as needed

›Maximum 3000 mg per 24 hours typical outpatient target

›NSAID option

›Ibuprofen 400 mg PO every 6 to 8 hours as needed

›Avoid in CKD, GI bleed risk, anticoagulation, pregnancy third trimester

›Bone healing effect uncertainty noted in counseling

›Opioid rescue if severe pain

›Hydromorphone 1 mg PO every 6 hours as needed

›Short course only

›Constipation prophylaxis consideration

Activity modification and rehab

›Relative rest strategy

›Stop impact loading

›Pain-free cross-training

›Swimming

›Cycling

›Deep water running

›Return progression

›Pain-free walking baseline

›Gradual run-walk program

›Avoid load jumps greater than 10% per week

›Risk factor correction

›Footwear review

›Gait and biomechanics assessment

›Strength work

›Hip abductors

›Calf complex

›Core stability

Bone health optimization

›Nutrition support

›Adequate caloric intake

›Protein adequacy

›Calcium intake target

›1000 to 1300 mg per day depending on age

›Vitamin D supplementation if low or risk high

›Typical maintenance 1000 to 2000 IU per day

›Repletion plan per local protocol if deficient

›Endocrine and menstrual health referral when indicated

›RED-S evaluation pathway

›Eating disorder services if suspected

Evidence and guideline framing

›Imaging recommendation level

›MRI preferred for suspected stress fracture with negative radiographs

›Class I recommendation in many sports medicine pathways for high-risk sites

›Return-to-sport decision principle

›Symptom-guided progression over time-only progression

›High-risk sites require specialist clearance

09Special Populations/sp28

Pregnancy

›Pregnancy considerations

›Radiation minimization

›Radiographs with shielding when needed

›MRI without gadolinium preferred for definitive diagnosis

›Analgesia choices

›Acetaminophen preferred

›NSAID avoidance in third trimester

›Thrombosis risk

›Pregnancy hypercoagulability with immobilization risk review

Geriatric

›Geriatric considerations

›Osteoporosis risk context

›Fragility fracture alternative if minimal load triggers pain

›Fall risk assessment

›Medication risks

›NSAID renal and GI toxicity higher risk

›Opioid delirium risk

›Workup escalation

›Pathologic fracture evaluation threshold lower

Pediatrics

›Pediatric considerations

›Growth plate and apophysis alternatives

›Osgood-Schlatter disease mimic

›Tibial tubercle apophysitis

›Salter-Harris injury alternative if trauma component

›Imaging approach

›Radiographs first

10Background/b26

Epidemiology

›Epidemiology overview

›Stress fractures common in runners and military recruits

›Tibia among most common stress fracture sites in running populations

›Fibula less common and usually lower risk than tibia

›Higher incidence with rapid training load increases

Pathophysiology

›Pathophysiology overview

›Bone remodeling imbalance

›Microdamage accumulation exceeds repair

›Load factors

›Repetitive impact loading

›Torsional stress with uneven terrain

›Site risk rationale

›Anterior tibial cortex tensile side risk for delayed union

›Posteromedial tibial cortex compressive side typically better healing

Therapeutic Considerations

›Nonoperative rationale

›Load reduction restores remodeling balance

›Pain-guided progression reduces refracture risk

›High-risk site rationale

›Anterior tibial cortex higher nonunion risk

›Earlier immobilization and specialist involvement favored

›Imaging rationale

›MRI detects early marrow and periosteal edema before cortical changes

›Radiographs useful for ruling out acute fracture and later healing signs

›Medication rationale

›Acetaminophen avoids platelet and renal risks

11Patient Discharge Instructions/pdi27

copy discharge instructions

›Discharge instructions

›Diagnosis

›Suspected stress fracture of tibia or fibula

›Activity

›No running or jumping until cleared

›Walking only as tolerated

›Use crutches if limping

›Immobilization

›Wear walking boot if provided

›Remove boot only for hygiene if allowed

›Elevation and swelling

›Elevate leg when resting

›Ice 15 to 20 minutes up to 4 times daily

›Pain control

›Acetaminophen as directed

›Avoid NSAIDs if pregnant, kidney disease, or ulcer history

›Follow-up

›Appointment within 7 to 10 days

›Earlier follow-up in 48 to 72 hours if high-risk site suspected

›Return to ED now

›Increasing pain despite rest

›New numbness or weakness

›Foot becomes cold, pale, or blue

›Severe swelling or tightness

›Fever or spreading redness

›Inability to bear weight that worsens

›New calf swelling or shortness of breath

12References/r9

Clinical guidelines and evidence sources

›Guidelines and consensus sources

›AAOS guidance on evaluation of suspected fracture and bone health considerations

›ACSM guidance on stress fracture risk modification and return-to-running principles

›Sports medicine consensus statements on high-risk stress fracture sites and MRI-first pathways

›ACR Appropriateness Criteria for suspected stress fracture imaging selection

›Evidence and reviews

›Systematic reviews comparing MRI, bone scan, CT, and radiographs for stress fracture diagnosis

›Cohort studies linking MRI grade to return-to-sport timelines

›Reviews on RED-S and bone stress injury prevention

Evidence & Review

Evidence & Review