# CIM Case: Calcaneal Stress Fracture ## Clinical Scenario **Patient:** 29-year-old male competitive runner **Presentation:** 6-week history of insidious onset left heel pain, worse with continuous exercise, improving with rest **Relevant history:** Marathon training, increased running volume from 30km to 50km per week over past 3 months, no history of trauma **Exercise pattern:** Runs 6 days per week, minimal cross-training, recently transitioned to minimalist footwear **Examination findings:** - Point tenderness over the medial and plantar aspect of the calcaneus - Positive calcaneal squeeze test - No visible swelling or bruising - Full range of ankle and subtalar motion - Normal gait when walking, antalgic when jogging - No signs of hyperpronation or cavovarus foot - Neurovascularly intact --- ## Investigations Provided ### Laboratory Results | Test | Result | Normal Range | Interpretation | |------|--------|--------------|----------------| | Vitamin D | 38 nmol/L | 50-150 nmol/L | Low - insufficiency | | Calcium | 2.35 mmol/L | 2.15-2.55 mmol/L | Normal | | Phosphate | 1.1 mmol/L | 0.8-1.5 mmol/L | Normal | | PTH | 5.2 pmol/L | 1.6-6.9 pmol/L | Normal | | TSH | 1.8 mU/L | 0.4-4.0 mU/L | Normal | ### Imaging **Image 1: Weight-bearing Lateral Foot Radiograph** **Radiological features:** - Normal calcaneal trabecular pattern - No visible fracture line - No periosteal reaction - No sclerosis - Normal Bohler's angle (28°) - No degenerative changes at subtalar joint **Image 2: MRI Left Foot (T1 and STIR sequences)** **MRI findings:** - Linear hypointense line within the posterior calcaneal tuberosity on T1 - Extensive surrounding bone marrow oedema on STIR - No complete cortical breach - Oedema extends from medial to lateral tuberosity - No soft tissue mass or fluid collection - Plantar fascia normal - Achilles tendon normal ## Questions & Model Answers **Diagnosis: Calcaneal Stress Fracture (High-Grade Bone Stress Injury)** This is a classic presentation of a calcaneal stress fracture in an endurance athlete. **Clinical Features Supporting Diagnosis:** | Feature | This Patient | Significance | |---------|--------------|--------------| | **Insidious onset** | Yes (6 weeks) | Typical of stress fracture, not acute injury | | **Activity-related pain** | Yes (worse with running) | Loading-dependent pain | | **Training overload** | Yes (30→50km in 3 months) | >10% weekly increase is risk factor | | **Positive squeeze test** | Yes | Sensitive for calcaneal stress fracture | | **Point tenderness** | Yes (medial/plantar) | Localised to fracture site | | **No acute trauma** | Yes | Excludes acute fracture | **Calcaneal Squeeze Test:** - Bilateral compression of the calcaneal tuberosity - Positive when reproduces patient's pain - Sensitivity ~80% for calcaneal stress fracture **Risk Factors in This Patient:** 1. Rapid training escalation (66% increase over 3 months) 2. Transition to minimalist footwear (alters loading) 3. Running on hard surfaces 4. Vitamin D insufficiency 5. Minimal cross-training (repetitive loading) > **Consultant Tip:** The combination of insidious heel pain in a runner with positive squeeze test should prompt investigation for calcaneal stress fracture even if X-ray is normal. **Why Plain Radiographs Are Normal:** Plain radiographs have poor sensitivity for early stress fractures: | Timing | Radiograph Sensitivity | Reason | |--------|------------------------|--------| | **0-2 weeks** | 10-15% | No visible changes | | **2-4 weeks** | 30-50% | Early periosteal reaction may appear | | **4-8 weeks** | 70-80% | Callus, sclerosis become visible | | **>8 weeks** | >90% | Established healing changes | **Why MRI is the Investigation of Choice:** | Modality | Sensitivity | Specificity | Advantages | Disadvantages | |----------|-------------|-------------|------------|---------------| | **MRI** | 99-100% | 80-100% | Gold standard, no radiation, grades severity | Cost, availability | | **Bone scan** | 95-100% | 30-70% | Sensitive | Poor specificity, radiation | | **CT** | 40-70% | 85-95% | Shows cortical detail | Radiation, misses early stress | | **X-ray** | 15-50% | 95% | Cheap, accessible | Poor early sensitivity | **MRI Grading (Fredericson Classification - Modified for Calcaneus):** | Grade | T1 Finding | STIR/T2 Finding | Management | |-------|------------|-----------------|------------| | **Grade 1** | Normal | Periosteal oedema only | Modify activity 2 weeks | | **Grade 2** | Normal | Bone marrow oedema on STIR | Modify activity 3-4 weeks | | **Grade 3** | Marrow abnormality | Bone marrow oedema | Protected weight bearing 4-6 weeks | | **Grade 4** | Visible fracture line | Bone marrow oedema | Non-weight bearing 6-8 weeks | **This Patient's MRI:** Grade 4 - Linear fracture line with extensive marrow oedema, requires 6-8 weeks non-weight bearing. > **Consultant Tip:** A normal X-ray does NOT exclude a stress fracture. MRI is the gold standard for diagnosis and grading severity. **Risk Factors for Stress Fractures:** **Extrinsic Factors (Training-Related):** | Factor | This Patient | Risk Level | |--------|--------------|------------| | **Rapid training escalation** | Yes (66% increase) | High | | **High weekly mileage** | Yes (50km/week) | High | | **Running surface** | Not specified | Moderate | | **Footwear change** | Yes (minimalist) | High | | **Single sport focus** | Yes (running only) | Moderate | | **Insufficient recovery** | Yes (6 days/week) | High | **Intrinsic Factors:** | Factor | Significance | |--------|--------------| | **Low bone density** | Major risk | | **Vitamin D deficiency** | This patient has insufficiency | | **Female athlete triad/RED-S** | Energy deficiency, menstrual dysfunction, low BMD | | **Previous stress fracture** | 2-5x increased risk | | **Anatomical variants** | Pes planus, cavus foot | | **Biomechanical abnormalities** | Leg length discrepancy | **Assessment for Underlying Metabolic Issues:** **Baseline Investigations:** 1. Vitamin D (25-OH) 2. Calcium, phosphate 3. PTH 4. TSH 5. Full blood count **In Female Athletes - Additional:** - Menstrual history (RED-S/Female Athlete Triad) - DEXA bone density - Oestrogen levels - Nutritional assessment - LEA (Low Energy Availability) screening **In Recurrent Stress Fractures:** - DEXA scan regardless of sex - Comprehensive metabolic workup - Sports dietitian referral - Endocrinology review **This Patient:** - Vitamin D = 38 nmol/L (insufficient, target >50) - Should supplement with cholecalciferol 2000-4000 IU daily - Consider DEXA if recurrent fractures > **Consultant Tip:** Always check Vitamin D in stress fractures. Insufficiency is common in athletes despite outdoor training. **Management of Grade 4 Calcaneal Stress Fracture:** **Phase 1: Acute Management (Weeks 0-6)** | Component | Recommendation | |-----------|----------------| | **Activity modification** | Complete cessation of impact activities | | **Weight bearing** | Non-weight bearing or protected weight bearing in CAM boot | | **CAM boot** | Consider for 4-6 weeks to offload calcaneus | | **Crutches** | Until pain-free walking | | **Cross-training** | Pool running, swimming, upper body (when pain allows) | **Phase 2: Progressive Loading (Weeks 6-12)** | Week | Activity | Progression Criteria | |------|----------|---------------------| | **6-8** | Pain-free walking, start cycling | No tenderness, pain-free walking | | **8-10** | Increase cycling, elliptical | Pain-free 30 mins walking | | **10-12** | Pool running, begin walk-run | Negative squeeze test | **Phase 3: Return to Running (Weeks 12+)** | Week | Running Programme | |------|-------------------| | **12** | Walk-run intervals (1 min run : 4 min walk) | | **13** | Progress intervals (2:3) | | **14** | Progress intervals (3:2) | | **15** | Continuous easy running 15-20 min | | **16+** | 10% weekly mileage increase maximum | **Adjunct Management:** | Intervention | This Patient | |--------------|--------------| | **Vitamin D** | Cholecalciferol 2000-4000 IU daily (target >75 nmol/L) | | **Calcium** | 1000-1200 mg daily if dietary intake inadequate | | **Physiotherapy** | Hip/core strengthening, gait retraining | | **Footwear** | Transition back to structured running shoes | | **Training plan** | Sports medicine/coach review for periodisation | **Monitoring:** - Clinical review every 2-4 weeks - Repeat Vitamin D at 3 months - Consider repeat MRI only if symptoms persist beyond 12 weeks > **Consultant Tip:** The 10% rule - never increase running volume by more than 10% per week. This patient increased by 66% in 3 months. **Differential Diagnosis of Heel Pain in Athletes:** **1. Bone Pathology:** | Condition | Features | Distinguishing Factors | |-----------|----------|----------------------| | **Calcaneal stress fracture** | Insidious onset, squeeze test positive | MRI shows fracture line | | **Calcaneal bone bruise** | Impact injury, squeeze test positive | MRI shows oedema, no fracture line | | **Sever's disease** | Adolescent, posterior heel pain | Open apophysis on X-ray | **2. Plantar Fasciitis:** | Feature | Plantar Fasciitis | Stress Fracture | |---------|-------------------|-----------------| | **Location** | Medial tubercle/plantar aponeurosis | Posterior tuberosity | | **First step pain** | Classic feature | Less common | | **Squeeze test** | Negative | Positive | | **Windlass test** | Positive | Negative | | **MRI** | Fascial thickening, no bone oedema | Bone marrow oedema ± fracture | **3. Achilles Pathology:** | Condition | Features | |-----------|----------| | **Insertional Achilles tendinopathy** | Posterior heel, at tendon insertion | | **Retrocalcaneal bursitis** | Posterior heel, prominent superior tuberosity | | **Haglund's deformity** | Bony prominence, shoe irritation | **4. Nerve Entrapment:** | Condition | Features | |-----------|----------| | **Baxter's nerve (first branch lateral plantar)** | Burning pain, sensory changes | | **Tarsal tunnel syndrome** | Tinel's positive, night pain | | **Medial calcaneal nerve** | Altered sensation heel pad | **5. Other:** | Condition | Features | |-----------|----------| | **Heel pad syndrome** | Atrophy of fat pad, direct plantar tenderness | | **Inflammatory arthropathy** | Enthesitis, bilateral, systemic features | | **Tumour (rare)** | Night pain, rest pain, systemic symptoms | **This Patient:** Positive squeeze test, insidious onset in runner with training overload, and MRI fracture line confirms calcaneal stress fracture. > **Consultant Tip:** Plantar fasciitis has first-step morning pain; stress fracture has load-related pain during exercise. **Prognosis for Return to Sport:** **Expected Outcomes for Calcaneal Stress Fracture:** | Outcome | Grade 4 (This Patient) | |---------|------------------------| | **Time to pain-free walking** | 4-6 weeks | | **Time to return to running** | 12-16 weeks | | **Time to full training** | 16-20 weeks | | **Return to competition** | 20-24 weeks | | **Full recovery rate** | >95% with appropriate management | **Factors Affecting Recovery:** | Favourable | Unfavourable | |------------|--------------| | Complete rest compliance | Continued training through pain | | Normal bone health | Metabolic abnormality | | Single first fracture | Recurrent stress fractures | | Addressing risk factors | Unchanged training errors | **Prevention of Recurrence:** **Training Modifications:** | Principle | Implementation | |-----------|----------------| | **10% rule** | Maximum weekly volume increase | | **Periodisation** | Build-taper cycles, recovery weeks | | **Cross-training** | Include non-impact activities | | **Rest days** | Minimum 1-2 per week | | **Surface variation** | Avoid continuous hard surface running | | **Gradual footwear changes** | 10-14 day transition period | **Biomechanical Assessment:** | Component | Intervention | |-----------|--------------| | **Gait analysis** | Address overstriding, increase cadence | | **Footwear** | Appropriate for foot type and surface | | **Orthoses** | Consider for biomechanical issues | | **Strength training** | Hip, core, calf complex | **Metabolic Optimisation:** | Target | This Patient | |--------|--------------| | **Vitamin D** | Target >75 nmol/L, recheck at 3 months | | **Calcium** | 1000-1200 mg/day | | **Energy availability** | Ensure adequate caloric intake for training | | **Sleep** | 8+ hours for recovery | **Long-term Monitoring:** - Annual metabolic bloods if history of stress fracture - DEXA if recurrent fractures - Regular training load monitoring > **Consultant Tip:** Address ALL modifiable risk factors - training load, nutrition, sleep, and biomechanics. One missed factor increases recurrence risk. --- ## Key Teaching Points ### Pattern Recognition **This pattern suggests Calcaneal Stress Fracture:** - Endurance athlete with high training volume - Insidious onset heel pain worse with exercise - Positive calcaneal squeeze test - Normal X-ray in early presentation - MRI shows bone oedema and fracture line **Comparison - Stress Fracture vs Plantar Fasciitis:** | Feature | Stress Fracture | Plantar Fasciitis | |---------|-----------------|-------------------| | Pain pattern | Activity-related | First-step morning pain | | Squeeze test | Positive | Negative | | Windlass test | Negative | Positive | | Tenderness | Posterior/medial tuberosity | Medial tubercle | | MRI | Bone marrow oedema | Fascial thickening | ### Critical Management Points 1. **Normal X-ray does NOT exclude stress fracture** - MRI is gold standard 2. **Grade severity using MRI** - guides treatment duration 3. **Protected weight bearing for Grade 4** - 6-8 weeks 4. **Address metabolic factors** - Vitamin D, calcium, energy availability 5. **Gradual return to sport** - 10% rule 6. **Prevention is key** - address training errors and risk factors --- ## Common Examiner Follow-ups **Q: "What if this was a female athlete with amenorrhea?"** This would suggest Relative Energy Deficiency in Sport (RED-S), formerly known as Female Athlete Triad: | Component | Features | |-----------|----------| | **Low energy availability** | Inadequate caloric intake for exercise expenditure | | **Menstrual dysfunction** | Amenorrhea or oligomenorrhea | | **Low bone density** | Z-score ≤-2.0 | Management: - Multidisciplinary team (sports medicine, dietitian, psychologist) - Increase energy availability - May require reduced training load - Endocrinology referral for severe cases - DEXA scan mandatory --- **Q: "What are high-risk vs low-risk stress fracture sites?"** | High-Risk Sites | Low-Risk Sites | |-----------------|----------------| | Femoral neck (tension side) | Calcaneus | | Anterior tibial cortex | Posterior tibial cortex | | Navicular | Fibula | | 5th metatarsal base (Jones) | 2nd-4th metatarsal shafts | | Talus | Pubic rami | | Patella | Sacrum | High-risk sites require more aggressive treatment (often non-weight bearing, sometimes surgery) due to risk of complete fracture, delayed union, or non-union. --- **Q: "When would you consider surgical intervention for a calcaneal stress fracture?"** Surgical intervention is rarely indicated but may be considered for: - Non-union despite 6+ months conservative treatment - Complete displaced fracture - High-level athlete with time-sensitive return requirements (controversial) Most calcaneal stress fractures heal with conservative management. --- ## Related Topics - Navicular Stress Fracture - 5th Metatarsal Stress Fractures (Jones Fracture) - Female Athlete Triad / RED-S - Plantar Fasciitis - Bone Stress Injury Continuum - Vitamin D and Bone Health