Tension vs Compression | MRI Gold Standard | Surgical Emergency if Tension Side
FEMORAL NECK STRESS FRACTURE TYPES
Critical Must-Knows
- Tension side (superior cortex) requires prophylactic surgical fixation - high displacement risk
- Compression side (inferior cortex) can be managed conservatively with non-weight bearing
- MRI is gold standard - X-rays often negative initially
- Female athlete triad - amenorrhea, low energy availability, low BMD
- Military recruits and runners are highest risk populations
Clinical Pearls
- "Groin pain in young athlete/military recruit = stress fracture until proven otherwise
- "X-rays often negative for 2-4 weeks - MRI for early diagnosis
- "Superior cortex involvement = surgical emergency (high displacement risk)
- "Return to sport requires MRI evidence of healing
Clinical Imaging
Imaging Gallery




Critical Femoral Neck Stress Fracture Exam Points
Tension vs Compression
This is THE exam question. Tension side (superior cortex) = surgical fixation required. Compression side (inferior cortex) = conservative management possible. Get this wrong and you fail.
MRI is Gold Standard
X-rays are often negative for 2-4 weeks. MRI shows bone marrow edema early. Always order MRI if clinical suspicion high and X-rays negative.
Female Athlete Triad
Low energy availability, menstrual dysfunction, low BMD. Must screen female athletes with stress fractures. Endocrine referral if triad suspected.
High-Risk Location
Femoral neck is a high-risk stress fracture location due to displacement potential and AVN risk. More aggressive management than tibial stress fractures.
Femoral Neck Stress Fracture Management Algorithm
| Fracture Type | Location | Treatment |
|---|---|---|
| Tension-side stress fracture | Superior cortex involvement | SURGICAL - prophylactic screw fixation |
| Compression-side stress fracture | Inferior cortex only | Non-weight bearing 6-8 weeks, serial imaging |
| Displaced fracture | Complete with displacement | Urgent surgical fixation (cannulated screws or DHS) |
| Compression side - not healing | Progressive symptoms at 6 weeks | Convert to surgical fixation |
| Bilateral stress reaction | Both hips affected | Address underlying cause, extended rest |
TENSION - STENSION - Superior Side Management
| T | Top of femoral neck (superior) Tension forces on superior cortex |
| E | Emergency surgical referral High displacement risk |
| N | Non-weight bearing while awaiting surgery Prevent displacement |
| S | Screw fixation (prophylactic) Cannulated screws |
| I | Imaging with MRI confirms Gold standard diagnosis |
| O | Osteonecrosis risk if displaced AVN complication |
| N | No delay in treatment Urgent surgical management |
| T | Top of femoral neck (superior) Tension forces on superior cortex | S | Screw fixation (prophylactic) Cannulated screws | N | No delay in treatment Urgent surgical management |
| E | Emergency surgical referral High displacement risk | I | Imaging with MRI confirms Gold standard diagnosis | ||
| N | Non-weight bearing while awaiting surgery Prevent displacement | O | Osteonecrosis risk if displaced AVN complication |
Hook:TENSION side = Top side = T for TROUBLE - needs surgery!
COMPRESSION - ICOMPRESSION - Inferior Side Management
| C | Conservative management possible Non-operative option |
| O | Off weight bearing 6-8 weeks Protected mobilization |
| M | MRI for monitoring healing Serial imaging |
| P | Progressive return to activity Gradual loading |
| R | Risk stratify for female triad Address underlying cause |
| E | Evaluate bone health DEXA, vitamin D |
| S | Surgery if fails or progresses Conversion to surgery |
| S | Serial clinical and imaging review Close follow-up |
| C | Conservative management possible Non-operative option | P | Progressive return to activity Gradual loading | S | Surgery if fails or progresses Conversion to surgery |
| O | Off weight bearing 6-8 weeks Protected mobilization | R | Risk stratify for female triad Address underlying cause | S | Serial clinical and imaging review Close follow-up |
| M | MRI for monitoring healing Serial imaging | E | Evaluate bone health DEXA, vitamin D |
Hook:COMPRESS = Can usually Conservative Manage if only inferior cortex
TRIAD - FTRIAD - Female Athlete Risk
| T | Training excessive (overload) Too much too soon |
| R | Reduced energy availability Caloric deficit |
| I | Irregular menses (amenorrhea) Hormonal dysfunction |
| A | Absent periods red flag Screen all female athletes |
| D | Decreased BMD Osteopenia/osteoporosis |
| T | Training excessive (overload) Too much too soon | A | Absent periods red flag Screen all female athletes |
| R | Reduced energy availability Caloric deficit | D | Decreased BMD Osteopenia/osteoporosis |
| I | Irregular menses (amenorrhea) Hormonal dysfunction |
Hook:TRIAD in female athletes = Think stress fracture and bone health
FULLERTON - CFULLERTON - Classification
| F | First degree - MRI only findings Periosteal edema |
| U | Usually conservative If early stage |
| L | Line visible on imaging Higher grade |
| L | Location matters (tension vs compression) Determines treatment |
| E | Endosteal involvement More advanced |
| R | Radiographic fracture line Grade 3-4 |
| T | Treatment based on grade and location Algorithm-driven |
| O | Operative if tension side or high grade Surgical indication |
| N | Non-operative if compression and low grade Conservative option |
| F | First degree - MRI only findings Periosteal edema | L | Location matters (tension vs compression) Determines treatment | T | Treatment based on grade and location Algorithm-driven |
| U | Usually conservative If early stage | E | Endosteal involvement More advanced | O | Operative if tension side or high grade Surgical indication |
| L | Line visible on imaging Higher grade | R | Radiographic fracture line Grade 3-4 | N | Non-operative if compression and low grade Conservative option |
Hook:FULLERTON classification guides treatment decisions
Overview and Epidemiology
Femoral neck stress fractures are overuse injuries occurring from repetitive submaximal loading, most common in endurance athletes and military recruits. They represent a high-risk stress fracture location due to displacement potential and AVN risk.
Historical context:
- First described in military populations
- Recognition of tension vs compression distinction critical
- Female athlete triad identified as major risk factor
High-Risk Location
Femoral neck stress fractures are classified as high-risk stress fractures due to the risk of displacement leading to AVN and nonunion. They require more aggressive management than low-risk stress fractures (tibial shaft, metatarsal).
Epidemiology:
- Femoral neck stress fractures account for approximately 3% of all sport-related stress fractures (Robertson & Wood 2017)
- Distance/marathon runners are the commonest athletic population affected; military recruits in basic training are the other key high-risk group
- Female predominance, strongly linked to the female athlete triad / RED-S; in mixed surgical military cohorts roughly half of operatively treated cases are women (Shaw 2022)
- Ballet dancers and other high-volume, leanness-emphasis athletes are also over-represented
- Across military basic training, the baseline incidence of stress fracture of any site is several percent over an 8-week cycle (5.9% per 8 weeks in the female Navy recruit RCT; Lappe 2008) — the femoral neck is a small but high-consequence subset
Risk factors:
- Training errors (too much, too soon)
- Female athlete triad (low energy availability, amenorrhea, low BMD)
- Low vitamin D
- Smoking
- Previous stress fracture
- Rapid increase in activity
Pathophysiology and Mechanisms
Femoral neck anatomy:
The femoral neck is vulnerable to stress fractures due to:
- High bending loads during weight-bearing activities
- Limited blood supply (risk of AVN)
- Thin cortical bone especially superiorly
Biomechanics of loading:
Superior cortex - TENSION forces:
During single-leg stance, the femoral neck experiences bending moments:
- Superior cortex is under TENSION (pulling apart)
- Inferior cortex is under COMPRESSION (pushing together)
Tension forces cause:
- Cracks to propagate rather than close
- Higher risk of complete fracture
- Potential for sudden displacement
This is why tension-side stress fractures are surgical emergencies - the crack can propagate and displace suddenly.
Stress fracture pathophysiology:
- Bone remodeling imbalance: Resorption exceeds formation
- Microdamage accumulation: Repetitive loading
- Stress reaction: Bone edema without fracture line
- Stress fracture: Fracture line develops
- Complete fracture: Full-thickness propagation
Early detection at stress reaction stage allows conservative management.
Classification Systems
Tension vs Compression:
| Type | Location | Risk | Treatment |
|---|---|---|---|
| Tension | Superior cortex | HIGH - displacement risk | Surgical fixation |
| Compression | Inferior cortex | Lower | Conservative possible |
| Complete | Both cortices | Highest | Surgical - urgent |
Location is THE key factor in management decisions. Always determine if the fracture involves the superior (tension) or inferior (compression) cortex.
Clinical Assessment
History:
Typical presentation:
- Young athlete or military recruit
- Insidious onset groin pain
- Activity-related symptoms
- Pain worse with impact activities
- May have preceding prodromal ache
Key history questions:
- Training history (recent increases?)
- Menstrual history (females)
- Dietary intake and RED-S screening
- Previous stress fractures
- Medication history (steroids, bisphosphonates)
RED-S Screening
In any athlete with stress fracture, screen for Relative Energy Deficiency in Sport (RED-S) - the updated term for female athlete triad. This includes low energy availability, menstrual dysfunction, and bone health issues.
Physical examination:
Key tests:
| Test | Technique | Finding |
|---|---|---|
| Gait assessment | Observe walking | Antalgic gait |
| Log roll | Passive rotation in extension | Groin pain |
| Hop test | Single leg hop | Pain reproduction |
| Fulcrum test | Femur over forearm as fulcrum | Pain with loading |
| FABER/FADIR | Hip ROM tests | Groin pain, reduced ROM |
Hop test:
- Should NOT be performed if high clinical suspicion
- Risk of displacing an incomplete fracture
- Use clinical judgment
Hop Test Caution
The single-leg hop test can reproduce pain but risks displacing an incomplete fracture. If clinical suspicion is high, proceed directly to imaging rather than provocative testing.
Differential diagnosis of activity-related groin/hip pain in the young athlete:
Differential Diagnosis - Athletic Groin/Hip Pain
| Diagnosis | Discriminating features | Key investigation |
|---|---|---|
| Femoral neck stress fracture | Insidious load-related groin pain, worse with impact; pain on log roll/axial loading; high-risk population | MRI (bone marrow oedema, fracture line, tension vs compression) |
| Femoroacetabular impingement / labral tear | Sharp anterior groin pain with flexion-rotation; positive FADIR; clicking/catching | MRI arthrogram; X-ray for cam/pincer morphology |
| Adductor / hip flexor tendinopathy or muscle strain | Pain on resisted adduction or hip flexion; localised tenderness; acute onset | Clinical; ultrasound/MRI if persistent |
| Athletic pubalgia / sportsman's groin | Lower abdominal and adductor-origin pain; pain on resisted sit-up and Valsalva | MRI of pubic symphysis and rectus/adductor aponeurosis |
| Pubic ramus / sacral stress fracture | Groin or buttock pain in runner; tender pubic ramus or sacrum | MRI of pelvis |
| Avascular necrosis of femoral head | Groin pain, steroid/alcohol history; pain on extremes of rotation | MRI (subchondral crescent, double-line sign) |
| Septic arthritis / transient synovitis | Rest pain, fever, marked ROM restriction, raised inflammatory markers | Bloods, aspiration; MRI/US for effusion |
Investigations
Clinical Imaging



Imaging approach:
Plain radiographs:
- Often negative for 2-4 weeks
- May show sclerotic line, periosteal reaction
- Full-length views recommended
- Compare to contralateral side
MRI (Gold Standard):
- Detects stress reaction before fracture line visible
- Shows bone marrow edema (T2/STIR hyperintense)
- Identifies fracture line if present
- Determines tension vs compression involvement
- Essential for early diagnosis
MRI Findings
MRI shows bone marrow edema (bright on T2/STIR, dark on T1) in stress reactions. A fracture line appears as low signal on all sequences. Location of findings determines if tension or compression side involved.
When to order MRI:
- Clinical suspicion with negative X-rays
- Early diagnosis critical (athletes in-season)
- Determine extent and location
- Monitor healing progress
CT scan:
- Better for visualizing cortical fracture lines
- Less sensitive for early stress reaction
- Useful if MRI contraindicated or equivocal
Bone scan:
- Highly sensitive but less specific
- Shows focal uptake at fracture site
- Less commonly used now due to MRI availability
- Cannot distinguish tension vs compression
Laboratory investigations:
- Vitamin D level
- Calcium
- TSH (if RED-S suspected)
- Consider DEXA for BMD (if triad/RED-S)
Management
SURGICAL MANAGEMENT REQUIRED:
Tension-side (superior cortex) stress fractures have high displacement risk and require prophylactic fixation.
Surgical options (implant choice matters):
- Multiple cannulated screws (typically 3, inverted triangle) — historically standard in young athletes with good bone
- Sliding hip screw (SHS) or cephalomedullary nail — increasingly favoured, especially in poorer bone, larger fractures or non-compliant patients; a fixed-angle device better resists varus and the implant choice may reduce the subtrochanteric stress-riser risk seen after isolated cannulated screws (Hwang 2022)
- Valgus osteotomy or arthroplasty reserved for salvage/non-union/AVN
Surgical technique:
- Supine on fracture table
- Image intensifier guidance
- 3 cannulated screws in inverted triangle, or SHS as above
- Ensure no screw in weight-bearing dome
- Avoid a low (distal) starting point that creates a subtrochanteric stress riser
Postoperative:
- Protected weight bearing initially
- Progress as healing confirmed
- Return to sport when united and pain-free
Do not delay surgery for tension-side fractures.
Surgical Technique
Patient positioning:
- Supine on fracture table or radiolucent table
- Image intensifier access for AP and lateral
- Slight internal rotation of leg
- Unaffected leg in lithotomy position
Preparation:
- Confirm fracture location on imaging
- Mark skin incision
- Ensure adequate fluoroscopy images
- Prepare for closed vs open approach
Most cases can be done percutaneously with fluoroscopic guidance.
Complications
Complications of Femoral Neck Stress Fractures
| Complication | Risk Factors | Prevention/Management |
|---|---|---|
| Displacement | Tension side, delayed diagnosis | Early surgery for tension side, non-weight bearing |
| Avascular necrosis | Displacement, delayed fixation | Urgent treatment, anatomic reduction |
| Nonunion | Displacement, inadequate fixation, metabolic factors | Revision surgery, bone grafting |
| Hardware failure | Inadequate fixation, early loading | Proper technique, protected weight bearing |
| Recurrence | Failure to address risk factors | Treat underlying causes, gradual return |
| Delayed union | Metabolic factors, inadequate rest | Extended non-weight bearing, optimize bone health |
Avascular necrosis:
- Most feared complication
- Risk increases with displacement
- Time to treatment matters
- May occur despite optimal care
- Monitor long-term
Nonunion:
- More common if displaced
- Risk factors: smoking, metabolic bone disease, poor fixation
- Treatment: revision with bone graft, valgus osteotomy, or arthroplasty
AVN Risk
AVN risk is directly related to degree of displacement and time to treatment. Tension-side fractures have higher AVN risk because they are more likely to displace. Urgent surgical fixation minimizes this risk.
Postoperative Care and Rehabilitation
Postoperative protocol:
- Protected weight bearing (toe-touch or partial)
- Hip ROM exercises
- Core and upper body conditioning
- Aquatic therapy when wound healed
- Serial X-rays at 2 and 6 weeks
- Progress weight bearing as healing allows
- X-ray to confirm early union
- Stationary bike
- Progressive hip strengthening
- Continue cross-training
- Full weight bearing when united
- Progress to impact activities
- Running progression (if athlete)
- Sport-specific training
- Final MRI to confirm healing
Return to sport criteria:
- Union confirmed on imaging
- Full, pain-free ROM
- Strength symmetry
- Functional testing passed
- Underlying risk factors addressed
Timeline for return:
- Compression side (conservative): 3-4 months
- Tension side (surgical): 4-6 months
- Displaced fracture: 6-12 months (depends on AVN)
Outcomes and Prognosis
Prognostic factors:
| Factor | Better Prognosis | Worse Prognosis |
|---|---|---|
| Location | Compression side | Tension side |
| Diagnosis | Early (stress reaction) | Late (complete fracture) |
| Displacement | Non-displaced | Displaced |
| Treatment timing | Urgent appropriate care | Delayed treatment |
| Underlying factors | Addressed | Unaddressed |
Expected outcomes by type (figures are approximate; outcome is dominated by displacement and time-to-diagnosis):
Compression-side (non-operative):
- High union rate with compliant non-weight bearing and serial imaging
- Return to sport typically 3-4 months
- Long-term prognosis excellent once healed, provided RED-S/metabolic drivers are corrected
Tension-side (operative):
- Good union with timely fixation
- Return to sport typically 4-6 months
- AVN risk increases with any displacement or delay
Displaced fractures:
- Markedly worse: high AVN and non-union risk; sporting outcomes considerably worse once displaced (Robertson & Wood 2017)
- May require arthroplasty if AVN develops
Outcomes are population-dependent — quote the evidence carefully
Athletic case series report encouraging return-to-sport rates when FNSF is caught early. However, in operatively treated military trainees, 58% were ultimately separated from service despite surgery, and 39% showed fracture-line progression (Shaw 2022). The lesson for the viva: outcome hinges on early diagnosis before displacement, the demand of the population, and correcting the underlying cause — not on the operation alone.
Prevention and Return to Sport
Primary prevention:
Training principles:
- Gradual load progression (10% rule)
- Adequate rest days
- Cross-training to reduce impact
- Proper footwear
- Appropriate running surfaces
Nutritional factors:
- Adequate caloric intake
- Calcium: 1000-1500mg daily
- Vitamin D: maintain greater than 75 nmol/L
- Avoid relative energy deficiency
Female athlete screening:
- Menstrual history in all female athletes
- RED-S screening questionnaire
- Low threshold for endocrine referral
- Bone health assessment if abnormalities
Secondary prevention:
- Address all modifiable risk factors
- Gradual return to sport
- Cross-training during recovery
- Long-term bone health monitoring
Evidence Base
Fullerton & Snowdy — Original Classification and Treatment Series
- 54 femoral neck stress fractures identified prospectively over 4 years
- Generated the tension / compression / displaced treatment classification
- Notably reported NON-progression of tension-side fractures under careful protocols, but displacement remains the catastrophic risk that justifies fixation
Robertson & Wood — Current Concepts Review (Sport)
- FNSF ~3% of sport-related stress fractures
- MRI is the key second-line investigation when radiographs are normal
- Delayed diagnosis drives displacement; sporting outcomes are considerably worse once displaced
- Early detection yields good return-to-sport rates
Shaw et al. — Operative FNSF in Military Trainees (CORR)
- Surgical threshold used: complete, tension-sided, or compression-sided involving more than 50% of neck width
- 39% showed fracture-line progression on repeat imaging
- T1 oedema extent plus effusion predicted final fracture size
- 58% separated from military service despite surgery
Hwang et al. — Implant Choice and Stress-Riser Risk
- Cannulated screws can create a subtrochanteric stress riser, particularly with low starting points or poor bone
- Sliding hip screw or cephalomedullary nail recommended over cannulated screws in many cases
- Mandatory metabolic work-up for all FNSF patients
Lappe et al. — Calcium and Vitamin D RCT (Stress-Fracture Prevention)
- Large double-blind RCT (n=5,201)
- 20% relative reduction in stress-fracture incidence with calcium + vitamin D
- Supports nutritional optimisation in high-risk loading populations
Barrack et al. — Cumulative Female Athlete Triad Risk (AJSM)
- BSI incidence scales with the NUMBER of Triad risk factors
- Single factor ~15-20%; combined factors 30-50%
- Low BMD + high training volume: OR 5.1
- Cumulative-risk model underpins the Triad Cumulative Risk Assessment
Roche/Nattiv et al. — Triad Risk and Trabecular-Rich BSI
- High Triad risk: 4.40x trabecular-rich BSI (e.g. femoral neck)
- Each 1-point Triad CRA increase: +26% trabecular-rich BSI risk
- Trabecular-rich sites are especially sensitive to biological/energy risk factors
AAOS / BOA / consensus guidance on high-risk stress fractures
- Femoral neck (tension side) is a recognised HIGH-RISK stress-fracture site
- High-risk sites warrant earlier imaging, protected weight-bearing and a lower surgical threshold
- Guidance is consistent across major societies on the tension/compression operative split
Exam Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Scenario 1: Young Runner with Groin Pain
"A 22-year-old female marathon runner presents with 4 weeks of activity-related groin pain. She has increased her training significantly in the past 2 months. X-rays are negative. How do you proceed?"
Scenario 2: Tension-Side Stress Fracture
"MRI shows bone marrow edema involving the superior cortex with a fracture line. How do you manage this?"
Scenario 3: Failed Conservative Management
"A 25-year-old male military recruit was diagnosed with compression-side femoral neck stress fracture and has been non-weight bearing for 6 weeks. Follow-up imaging shows fracture line progression. What do you do?"
MCQ Practice Points
Tension vs Compression
Q: Which side of the femoral neck requires prophylactic fixation? A: The tension side (superior cortex). It carries a high risk of progression and displacement with subsequent AVN, so prophylactic fixation is advised even when minimally displaced. Compression side (inferior cortex) fractures are more stable and can often be managed conservatively with close imaging follow-up.
MRI Sensitivity
Q: What is the gold standard imaging for suspected stress fracture with negative X-rays? A: MRI. It has 100 percent sensitivity and detects bone marrow edema weeks before a fracture line is visible on X-ray (which has only 10-40 percent sensitivity early on).
Female Athlete Triad
Q: What are the components of the Female Athlete Triad? A: Low energy availability, menstrual dysfunction, and low bone mineral density. This increases stress fracture risk by 2-4x and must be screened for in all female athletes.
Surgical Configuration
Q: What is the recommended screw configuration for femoral neck fixation? A: Three cannulated screws in an inverted triangle pattern. This provides optimal stability. Screws must assume a position along the calcar and avoid the weight-bearing dome.
Vitamin D Target
Q: What is the target Vitamin D level for stress fracture healing? A: Greater than 75 nmol/L. Levels below this impair bone healing and increase recurrence risk. Supplementation is part of standard management.
AVN Risk
Q: which factor most strongly correlates with AVN risk? A: Displacement. The degree of displacement and time to reduction/fixation determines the risk of vascular disruption to the femoral head.
Guidelines, Registries & Global Practice
Femoral neck stress fracture (FNSF) is a globally consistent diagnosis with a single overriding management principle — location (tension vs compression) and displacement drive treatment — that holds across every major board and health system.
Global epidemiology:
| Population | Setting | Relative risk / notes |
|---|---|---|
| Long-distance / marathon runners | Athletic | Commonest civilian group; FNSF approximately 3% of sport-related stress fractures (Robertson & Wood 2017) |
| Military recruits (basic training) | Occupational | High-volume new loading; baseline all-site stress fracture ~5-6% per training cycle (Lappe 2008); FNSF a high-consequence subset |
| Female athletes with RED-S / triad | Athletic | Risk rises with cumulative triad factors; high-risk runners ~4.4x trabecular-rich BSI (Roche 2023, Barrack 2014) |
| Ballet / leanness-emphasis sports | Athletic | Over-represented via low energy availability |
| Middle-aged / older with metabolic bone disease | General | Insufficiency-type FNSF; consider osteomalacia, osteoporosis, coxa vara (Tomar 2020) |
Major guidance, side by side:
| Body | Position on FNSF | Evidence basis |
|---|---|---|
| AAOS / US sports medicine | Femoral neck (tension side) classed as a HIGH-RISK stress fracture: image early, low threshold for fixation; tension-sided and displaced → surgery | Expert consensus + cohort data (Level III-IV) |
| BOA / BOAST (UK) | Treat as fragility/at-risk presentation where relevant; urgent senior review and theatre for displaced neck fractures; metabolic work-up | Consensus / standards |
| AO Foundation | Fixation principles: stable internal fixation for unstable/tension or displaced patterns; fixed-angle implants where bone quality is poor | Mechanistic + cohort |
| IOC / international RED-S consensus | Mandatory screening and treatment of low energy availability in any athlete with a bone stress injury | Consensus (Level II-III supporting data) |
There is no genuine international disagreement on the core algorithm: the tension/compression split and the imperative to fix tension-sided and displaced injuries are universal. Practice variation lies mainly in implant choice (cannulated screws vs sliding hip screw / cephalomedullary nail) and in the surgical threshold for compression-sided injuries — a commonly cited operative trigger is involvement of more than ~50% of the neck width or any fracture-line progression (Shaw 2022).
Registry note: FNSF is not separately tracked in arthroplasty registries (NJR, AJRR, AOANJRR, SHAR), but those registries do inform salvage outcomes when AVN or non-union leads to arthroplasty in a young patient — generally good implant survival but a high revision burden over a long expected lifespan, reinforcing the priority of joint-preserving early fixation.
Global practice variation:
- High-resource settings: ready MRI access enables early diagnosis at the stress-reaction stage; multidisciplinary RED-S pathways (sports physician, dietitian, endocrinologist).
- Limited-resource settings: reliance on radiographs and bone scan delays diagnosis, increasing displacement and AVN; a higher index of suspicion and earlier protected weight-bearing partly offset limited cross-sectional imaging.
Multidisciplinary pathway (universal): sports/orthopaedic assessment → urgent MRI → operative vs protected non-operative care by location → metabolic and RED-S work-up → staged return to load with bone-health optimisation.
Exam Cheat Sheet
Femoral Neck Stress Fractures
Clinical summary
Key Decision - Tension vs Compression
- •TENSION (superior cortex) = SURGERY
- •COMPRESSION (inferior cortex) = Conservative possible
- •Tension side: high progression/displacement risk - fix even if minimally displaced
- •Compression side: more stable - non-weight bearing with serial imaging
- •Surgical threshold for compression side: progression or involvement of more than half the neck width
- •This is THE exam question - get it right!
Diagnosis
- •MRI is gold standard (X-rays often negative)
- •Bone marrow edema on T2/STIR (early sign)
- •Fracture line visible in higher grades
- •Full-length femur X-ray to rule out shaft involvement
- •Determine tension vs compression involvement
Surgical Technique
- •Three cannulated screws (6.5-7.3mm)
- •Inverted triangle configuration
- •Fluoroscopic guidance (AP and Lateral)
- •No screw in weight-bearing dome
- •Posterior cortex engagement essential
Female Athlete Triad/RED-S
- •Low energy availability (dietary)
- •Menstrual dysfunction (amenorrhea)
- •Low bone mineral density (osteopenia)
- •Screen ALL female athletes with stress fractures
- •involve sports dietitian and endocrinologist
Complications
- •AVN - related to displacement degree
- •Nonunion - metabolic factors/smoking
- •Recurrence - if risk factors not addressed
- •Hardware failure if early weight bearing
- •Coxa vara deformity if reduction lost
Return to Sport
- •Union confirmed on imaging (MRI/CT)
- •Pain-free with activity and hop test
- •Underlying causes addressed (Vitamin D)
- •Gradual return with cross-training
- •Typically 3-6 months depending on severity