bowing legs.pptx

Bow Legs is a common clinical encounter often with parental anxiety - One must know whats normal and when to think abnormal

1. Bow Legs – Physiological Vs Pathological Dr. VANNALA RAJU Asst. Prof - pediatrics

2. Learning Objective Approach to a child presenting with bowing of legs To differentiate between Physiological and pathological bowing

3. INDEX CASE

4. HISTORY OF PRESENT ILLNESS… Bowing of legs noticed by parents since the child started walking for last 5 months. Present in both the legs, no progression normal walking pattern No h/o pain No h/o delay in walking Gaining wt adequately No h/o polyuria , polydipsia , recurrent loose stools.

5. Past history: Not significant, no h/o any chronic illness Family history: No h/o similar complaint in other family members. Birth history: FT Emg LSCS (Transverse lie), 3.5 kg cried immediately

6. Developmental history : Normal Gross: standing with support at 10 mnths standing without support at 11 mnths walking without support by 14 mnths since then noticed bowing of legs Immunization: complete for age according to NIS BCG,OPV,DPT,HiB (3 doses+booster ), HepB (3 doses), Measles, MMR.

7. Dietary history: Exclusively breast fed for 6 months and then complementary feeding started but breast feeding was continued and not started on top feeds . Now on predominant breast feeding +home based food.

8. General Examination Anthropometry Wt 12 kg (0 to +2 Z score) Length 83 cm (0 to +1 Z score) OFC 48 cm( +1 to +2 Z score )

9. ON EXAMINATION… No pallor, icterus , clubbing, lymphadenopathy B/l genu varum (bowing of legs) Ant Fontanelle closed No other signs s/o rickets No other skeletal deformity systemic examination : Abdomen: no Organomegaly,BS + CVS: S1 S2 normal, no murmur Resp : B/L Equal air entry, NVBS, No added sounds CNS: Normal

10. ON EXAMINATION… Musculoskeletal system: B/L genu varum , symmetrical Intercondylar distance: 4.5cm (Abnormal >6cm) Joints: Normal

11. Clinical Impression: Physiological Genu Varum (Bowing of legs) ?to r/o Vitamin D Deficiency

12. GENU VARUM Genu Varum is a Latin term used to describe bow legs. It is a common pediatric deformity. It can be physiological (most common) or pathological. Lower Extremity bowing is often a normal physiological process that commonly occurs in walking children below the age of 2 years and spontaneously resolves with time. Nelson 19 th Ed.

13. Physiological bowing of legs The constraint of space within the uterus during gestation forces the lower extremity to lie in a position with flexion of the hips and knees and internal rotation of the tibia and feet. This birth position causes contracture of the medial knee capsule. This internal rotation contracture of the knee leads to external rotation of the entire lower limb and the clinical genu varum posture of the infant.

14. Physiological bowing of legs These contractures stretch, and spontaneous resolution of this “physiologic” bowing is seen. This usually occurs between 18 to 22 months of age. The correction continues over the next 2 to 3 years. Overcorrection to a maximum genu valgum is noted between 3.5 and 4 years of age . The valgus angle decreases and reaches the adult 5° to 8° of valgus by the age of 7 years.  Clinical & Radiological Ev of bow legs .   Curr Opin Pediatr   2001

15. J Pediatr Orthop   2001

16. Salenius and Vankka’s graphic chart demonstrating the changes in tibiofemoral angles from time of birth until early adolescence Pathology falls two SD from these norms. J Bone Joint Surg Am 57:259-261

17. Classification of Genu Varum (bow legs) Physiological Pathological Asymmetric Growth: Tibia Vara ( Blounts disease) Physical injury Trauma Infection Tumor Metabolic disorders Vitamin D Def(Nutritional rickets) Vitamin D resistant rickets Hypophosphatasia Skeletal Dysplasias Metaphyseal dysplasias Achondroplasia Enchondramatosis

18. Pathological Genu Varum Patients usually are over the age of 2 -3 years Demonstrate significant amounts of residual bowing measured by the tibiofemoral angles that are 2 or more SD from normal. Pathologic deformities tend to occur more unilaterally /asymmetry. Derotation maneuvers of the tibia will not demonstrate correction of the varus deformity at the knee. Clinically they also present with a lateral thrust due to varus instability at the knee.

19. Clinical Evaluation… History: nutritional status, Developmental milestones, Family history Examination: Stature, nutritional status Specific Examination for bowed legs: Derotation test : Tibia is externally rotated to match the externally rotated femur—if deformity disappears—Physiological

20. Clinical Evaluation.. Intercondylar distance: >6cm—abnormal Davids et al,J Pediatr Orthop,2000

21. Radiographic evaluation of bowed legs… Tibiofemoral Angle : Curr Opin Pediatr   2001;

22. Radiographic evaluation of bowed legs… Tibial Metaphyseal-Diaphyseal angle: Cut off: >11 in >2yrs of age and >16 in <2 yrs of age is pathological Given by Levine and Drennan ( Drennan’s angle) J Pediatr Orthop, Vol. 21, No. 2, 2001

23. Radiographic evaluation of bowed legs… Mechanical Axis: Cut-off >30 Larger value indicates a greater Varum deformity J Pediatr Orthop, Vol. 21, No. 2, 2001

24. Physiological genu varum Age<2-3 yrs Gentle and symmetric deformity Bilateral and less severe,painless No significant lateral thrust Derotation test: deformity disappears Intercondylar distance<6cm M-D angle<11 Pathological genu varum Age >2 yrs Asymmetric,abrupt , sharp angulation Unilateral/bilateral and increased severity, pain Significant lateral thrust Derotation test – ve Intercondylar distance >6cm M-D angle >11 History/ Ex:Vit D Def, Short stature,skeletal dysplasias . Trauma.

25. Indication of Radiograph: Full-length standing bilateral anteroposterior Radiographs From Hip To Ankle Should Be Obtained To Assist With Evaluation Of The Mechanical axis Age >2-3 years Unilaterality , increased severity ( tibiofemoral angle>2 S.D), pain, knee instability Progressive deformity, lack of spontaneous resolution History/examination s/o pathological type of genu varum

26. Treatment of Physiological bowing of legs.. Reassurance and Observation Re-evaluate 3-6 mnthly for spontaneous resolution of the deformity. For the overly concerned parent, “treatment” to expedite this natural resolution consists of daily knee stretches Curr Opin Pediatr   2001;

27. INVESTIGATIONS: X-Ray of the Index case

28. X-Rays

29. Biochemical : Ca - 10.4 Ph - 6.2 ALP - 335 U/L (>420) Vitamin D levels: 9.6 (deficient) Mother’s Vitamin D levels :12.4 (deficient)

30. Final Diagnosis: Physiological Genu Varum with Hypovitaminosis D

31. Management in the index case… Reassurance Dietary advice Vitamin D and Ca supplement: 1000 IU/Day Mother treated with Vitamin D and Calcium supplements Plan :To follow up 3 mnthly to look for resolution .

32. Take home message…. Genu varum is part of the normal development of the lower extremity in young children . Most common cause of bowed legs in infancy is physiological. Persistence of bowing of legs>2-3 yrs is pathological Evaluating a child with bow legs: look for subtle differences in history, examination and radiographic findings to differentiate between physiological and pathological Genu varum .

33. THANK YOU