High-risk tibial stress fracture in a young runner with low energy availability
Ms D, 19, is a national-level 1500 m runner. She has had 6 weeks of right shin pain, now focal over the distal tibia, and a recent MRI shows a grade 4A distal tibial stress fracture. She has been amenorrhoeic for 9 months, has a BMI of 18.1, and reports low energy availability after cutting dairy and carbohydrates. She runs 90 km per week and does two gym sessions. She wants to race the national championships in 10 weeks and asks if she can cross-train hard and keep her weight down. She has no history of eating disorder treatment but reports body dissatisfaction. Examination shows focal tenderness and no swelling, with normal neurovascular status.
1. How would you risk-stratify this injury and decide the return-to-run timeline?
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This is a high-risk stress fracture because it is distal tibial, grade 4A, and occurring in a runner with low energy availability and prolonged amenorrhoea. High-risk sites have a greater risk of delayed union, non-union, and complete fracture.
I would not allow running at 10 weeks simply because she wants to race. I would arrange same-week orthopaedic review for weight-bearing status and consider whether immobilisation or surgery is needed. Return to running would be conditional on:
- Clinical resolution of focal tenderness,
- Imaging evidence of healing if the orthopaedic team requests it,
- Normalising energy availability and restoring menses or at least addressing the endocrine picture,
- Pain-free hopping and progressive loading.
A realistic timeline is often 3–6 months, not 10 weeks. Cross-training may be permitted only within the weight-bearing restrictions set by orthopaedics; 'hard' cross-training could shear the fracture. The key reasoning is that the fracture is a symptom of a system problem, and racing would risk her long-term career.
2. What multidisciplinary management would you put in place, including nutrition and bone health?
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I would assemble a sports physician, orthopaedic team, physiotherapist, and dietitian with eating-disorder expertise, and involve her coach with her consent.
- Bone: ensure calcium and vitamin D intake are adequate, check vitamin D and consider DXA if amenorrhoea persists or fracture is recurrent. I would not rely on oral contraceptives to restore bone health; they do not reverse low energy availability.
- Nutrition: increase energy availability by adding carbohydrate and dairy or alternatives, and set a no-weight-loss agreement during recovery. A dietitian should assess eating behaviour and body image, not simply prescribe a calorie target.
- Training: replace running with permitted non-weight-bearing conditioning, but make clear that this is not a way to maintain a large energy deficit.
- Psychological: screen for disordered eating and refer early; body dissatisfaction is a risk marker.
I would document the plan and share it with the coach only with consent, explaining that performance will improve with restored energy availability, not with further weight loss.
3. She asks, 'Can I cross-train hard and keep my weight down?' How would you answer, and what would you document?
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I would answer directly: no, not 'hard' cross-training and not weight loss. The fracture needs protected healing, and hard cross-training can load the tibia or create a new injury. Weight loss in the presence of low energy availability worsens bone health, menstrual function, immunity, and performance.
I would explain the concept of relative energy deficiency in sport: when energy intake does not meet exercise and baseline needs, the body down-regulates reproduction and bone formation. Her amenorrhoea and stress fracture are clinical signs, not separate problems.
I would offer a negotiated plan: permitted cross-training according to orthopaedic advice, a dietitian-led increase in intake, and a review of body composition only if clinically indicated-not as a performance target. I would document the discussion, her understanding, the no-weight-loss agreement, and the safety-net plan. If she cannot accept the plan or shows escalating disordered eating, I would refer urgently to specialist eating-disorder services.