What it is

Stress fractures of the femoral neck or acetabulum are small cracks in bone caused by repetitive load that exceeds the bone’s current capacity. They are high-consequence injuries that need prompt assessment.

Groin pain rises with running or hopping and may persist at night. Femoral neck tension-side injuries are particularly risky.

What happens when it occurs

Bone remodels in response to load. When breakdown outpaces repair, microdamage accumulates and a stress fracture forms. Ongoing loading risks a complete fracture.

Common causes and risk factors

  • Rapid mileage increases and hard surfaces
  • Low energy availability, menstrual disturbance, or low vitamin D
  • Poor sleep and recovery, footwear or technique changes

Who is most affected

Distance runners, triathletes, football codes in pre-season, and military trainees.

Typical symptoms

  • Deep groin pain with running and hopping
  • Pain on single-leg stance or heel strike
  • Night pain in more advanced cases

When to seek care

Immediate assessment is needed when groin pain prevents running or hopping or disturbs sleep. Avoid running until reviewed.

How we diagnose

Clinical tests reproduce pain with hopping and single-leg stance. MRI confirms the injury and defines risk level. X-rays may be normal early.

Management

  • Non-weight bearing or partial weight bearing for high-risk patterns
  • Graduated return after pain settles and imaging improves
  • Address nutrition, training load, sleep, and footwear
  • Surgical fixation for tension-side femoral neck or displaced fractures

Rehabilitation milestones

Phase 1 weeks 0 to 6: unload with crutches as advised, pain-free daily tasks, cross-training without impact.

Phase 2 weeks 6 to 12: progressive weight bearing, strength for hips and calves, walk programme.

Phase 3 months 3 to 4: return-to-run programme with careful progressions.

Phase 4 months 4 to 6: build speed, hills, and sport-specific drills.

Readiness to progress

  • Pain-free walking distance and hopping
  • Hip and calf strength within 90 percent
  • MRI or clinical signs of healing for high-risk patterns

Prevention

  • Gradual training progressions and rest days
  • Adequate energy availability and vitamin D sufficiency
  • Technique review and appropriate footwear

Australia snapshot

  • Seen in distance runners and football codes during pre-season build-ups
  • Female athletes and athletes with low energy availability are at higher risk
  • Fast access to MRI in cities speeds diagnosis and planning

Latest insights

This is a manage-the-risk injury. Protect the bone early and correct the load-recovery imbalance.

Nutrition and training planning reduce recurrence.

Frequently Asked Questions

A stress reaction is earlier bone overload without a visible crack. It can heal quickly when load is corrected.

Yes for suspected femoral neck or acetabular stress injury. MRI guides risk and return planning.

When you can walk and hop pain-free and your team clears progression. Many return to running between 8 and 16 weeks depending on severity.

Yes if pain-free. These maintain fitness while bone heals.

Rapid training spikes, low energy availability, menstrual disturbance, low vitamin D, poor sleep, or abrupt footwear or surface changes.

Comfortable shoes that suit your stride help. A technique and footwear review is part of the plan.

Risk is low when nutrition, training progressions, and recovery are well managed.