Stress fracture: Causes, Investigation, Diagnosis, Treatment

Stress/Fatigue fractures are discussed in detail. Their causes, most common sites, investigation, management.

1. STRESS FRACTURES

2. TOPICS DEFINITION EPIDEMIOLOGY PATHOGENESIS RISK FACTORS CLINICAL FEATURES EXAMINATION INVESTIGATION DIFFERENTIAL DIAGNOSIS PREVENTION TREATMENT DISCUSSING INDIVIDUAL SITES

3. DEFINITION Stress fractures/Fatigue fractures: Normal bone is subjected to repeated episodes of stress, less severe than that necessary to produce an acute fracture Different from Insufficiency fractures

4. EPIDEMIOLOGY Common in elite athletes & military recruits. 1% incidence in athletes, 20% in runners. Weight bearing lower limb bone prone Tibia – [50%] most common Neck femur, Tarsals & metatarsals Females are more prone Female athlete triad- eating disorder, amenorrhea/oligo, decreased bone mineral density

5. PATHOGENESIS Rapid increases in the frequency, duration, or intensity of an athletic activity without adequate periods of rest Disrupts normal bone remodeling Osteoclast-mediated bone resorption in the haversian canals and interstitial lamellae Small cracks appear at the cement lines of the haversian systems, which propagate into microfractures New bone formation occurs as a result of increased periosteal osteoblastic activity.

6. RISK FACTORS Extrinsic risk factors Training regimen Training surface Intrinsic risk factors Malalignment*, Limb length discrepency Nutrition Overweight Smoking Non-steroidal anti-inflammatory drugs *Malalignment: Anatomic and alignment factors such as tibia vara , pronation, cavus , limited joint motion, and decreased vascularity may be contributing factors in stress fractures of the lower leg and foot

7. CLINICAL FEATURES History of unaccustomed & repeated activity. Pain on exertion is the hallmark (worsens with activity and improves with rest) General health, medications, diet, and menstrual history in women Increase in training volume or intensity, a change in technique or surface, or an alteration of footwear

8. EXAMINATION Limb biomechanics - leg length discrepancy, or muscle imbalance, excessive subtalar pronation . Tenderness Pain often can be elicited by percussion over a distant site of the involved bone. Soft-tissue swelling can be seen(esp.-foot) Inaccessible sites – femoral neck - movts

9. INVESTIGATION X Ray Scintigraphy MRI CT Scan

10. X- RAY Normal – 1 st 2-3 wks after the onset of symptoms Periosteal response – 3 months after onset of symptoms. Periosteal bone formation, sclerosis, endosteal callus, and a frank fracture line.

11. Tibia Stress Fracture

12. Femur Neck Stress Fracture

13. March fractures

14. Scintigraphy Sensitive method It detects the osteoblastic activity associated with remodelling . Acute stress fractures are depicted as discrete, localized, areas of increased uptake of a Tc-99m Lacks specificity.

15. MRI Both sensitive and specific It is extremely sensitive in the detection of pathophysiological soft-tissue, bone and marrow changes associated with stress fractures Soft tissue- collection in infection, mass in tumor can be well visualised

16. CT-scan Disruption in normal cortical pattern is better seen then xray Less sensitive then MRI or Bone scan

17. DIFFERENTIAL DIAGNOSIS Periostitis , Bursitis, infection Avulsion injuries, muscle strain Neoplasm Exertional compartment syndrome

18. PREVENTION Training errors - most frequent culprit and should be corrected. Assessment of the type and condition of the running shoes Viscoelastic insoles, may help reduce the incidence of lower-extremity stress fractures. Education – parents, coaches, military personnel – periodic rest. Female athletes – alerted , eating disorders, hormonal abnormalities.

19. TREATMENT Rest Surgical treatment is needed for certain fractures

20. DISCUSSING INDIVIDUAL SITES Femoral neck Tibia Metatarsal Navicular

21. FEMORAL NECK Complaint of groin pain associated with activity Pain with movement of the hip and often a reduction in range of motion. T/t is based on the prevention of displacement. If displacement occurs, nonunion, varus deformity, and osteonecrosis can result.

22. Treatment The Stable Compression-type Fracture Avoid weight bearing Serial radiographs to ensure that displacement is not occurring and that healing is progressing. Fracture healing may require up to 2 months from the time of diagnosis. Return to activity requires - resolution of pain, - a full range of motion of the hip, restoration of muscle strength and endurance, radiographic evidence of a healed fracture. Fracture on tensile surface Internal fixation with CCS

23. TIBIA Progress to nonunion or complete fracture despite rest BECAUSE-tensile forces and hypovascularity Treatment : Electrical stimulation is combined with immobilization Non- wt bearing for 8-12 wks Monitor clinically, radiologically for healing If this regimen is unsuccessful, and the patient remains symptomatic, surgical treatment is indicated. If a single fracture exists, excision of the fracture site with cancellous bone grafting can be used, but for multiple fracture lines, intramedullary nailing is preferred

24. METATARSAL FRACTURES Treatment: Strict avoidance of weight bearing for 6 to 8 weeks. Limb elevation Ice fomentation Cycling / aquatic therapy Once healed- increase intensity of exercise gradually (10% per week)

25. Treatment Dancer and jones usually present as acute traumatic event but usually has h/o pain prior to traumatic incident A vulsion injuries usually heal without the need for surgical treatment, Fracture of the proximal diaphysis often requires operative treatment, especially in the active patient.

26. TARSAL NAVICULAR The initial treatment of non-displaced navicular stress fractures is avoidance of weight bearing and immobilization in a short leg cast for 8 weeks. Surgical treatment is indicated for fractures that are displaced at initial presentation or fail to heal with immobilization. The preferred method of surgical treatment is open reduction and internal fixation with lag screws.