Thigh and knee pain in an obese 10 year old

1. Thigh and knee pain in an obese 10 year old Pediatric Case Presentation By Annerie Hattingh 28 October 2009

2. History • 10 yr old boy presents to ED with 1 week history of ® thigh + knee pain. • He states that the pain is mainly in the thigh, but radiates down to his knee. • He was playing soccer when he collided with another player + fell. • Noted severe pain in his thigh + had to limp home on his left leg. • Since then, he has been complaining of pain in his ® thigh when bearing weight.

3. History • The pain would subside when lying down. • He did not improve much + was brought to ED. • He had no history of fever, rash, chest discomfort or pains in other joints.

4. Examination • Vitals: Temp 37’C (oral) PR 66 RR 20 BP 112/65 • Weight: 59.3kg (>>95th percentile) • Height: 152cm (> 95th percentile) • Alert, cooperative + in no distress when lying down. • Obese + large for age.

5. Examination • CVS: HR regular (-) murmurs • Lungs: clear • Abdo: Round contour Soft Non-tender

6. Examination • Musculoskeletal: • ® lower extremity: - Moderate tenderness in the upper ant. thigh - Severely tender hip, restricted ROM - Pubic symphysis non tender - Knee, tib-fib + foot non tender, normal ROM - No joint swelling noted

7. Examination • Musculoskeletal: • (L) lower extremity: - Mild tenderness of the hip on palpation - Mild tenderness on ROM testing - Rest unremarkable • NOTE: Although his chief complaint is thigh pain, the hip and knee joints should also be examined. • Hip injuries often present with knee pain.

8. Special investigations • X-rays of the hips are ordered.

9. Diagnosis • History of collision + fall suggests an acute injury such as a non-displaced #. • An obese child with hip pain in this age group should always raise the possibility of a SLIPPED FEMORALEPIPHYSIS. • The X-ray shows a slipped capital femoral epiphysis on the ®. • The left hip appears to be normal, however an early slip on the left is difficult to rule out.

10. Management • He is hospitalized and bed rest ordered. • After a few hours of bed rest, his left hip is no longer tender. • He is referred to the orthopedic surgeon + taken to the OR for internal fixation of his ® femoral epiphysis.

11. Discussion • Radiographic dx of slipped femoral epiphysis can be subtle. • Clinical suspicion very important.

12. Discussion • In this case, the physis appears to be wider + more lucent in the ® hip, compared to the left.

13. Discussion • The position of the femoral head epiphysis should resemble a cap over the physis. • Subtle cases may just show a slight malpositioning of the epiphysis.

14. Discussion • Examine the following diagram of the pt’s hips:

15. Discussion • The lines drawn along the superior border of the prox. femur metaphysis (the Klein line) should intersect part of the prox. femoral epiphysis.

16. Discussion • The pt’s ® hip ( left on the screen ) shows the line just touching the lateral margin of the epiphysis.

17. Discussion • This is abnormal, indicating that the femoral epiphysis has slipped inferiorly + medially.

18. Discussion • The normal left hip (right on the screen) shows the line intersecting the lateral part of the femoral epiphysis.

19. Discussion • View this obvious case:

20. Discussion • No line needs to be drawn here to appreciate that the pt’s left hip is abnormal. • Severe left slipped femoral epiphysis.

21. Discussion • The slipped epiphysis on the ® may not be so obvious. • Bilat. SFE is present, severe on the L + moderately severe on the R.

22. Discussion • SCFE is a Dx that will occasionally present to the ED with an acute, sub acute or chronic pain in the hip, thigh or knee. • The Dx is not difficult if it is considered!! • Vague symptoms may be present • Degree of pain may range from severe to non-existent. • Ambulatory ability may range from non-weight bearing to normal gait.

23. Discussion • Often wrongly diagnosed as: - pulled muscle - hip bruise - hip/knee sprain • Patients tend to keep their hip externally rotated with inability to fully internally rotate the hip.

24. Discussion • Risk factors: • Cause is unknown. • 3-4 x more common in males than females. • Average age 10 – 16 years. • Pt’s are overweight for height/obese. • Associated with endocrine disorders like hypothyroidism, pituitary tumors + low growth hormone levels. • May be associated with minor fall or trauma

25. Discussion • Radiographic diagnosis: • Obvious cases - epiphysis obviously displaced • Subtle cases - epiphyseal plate (physis) may be widened / irregular compared to the other side. • A line drawn along the sup. border of the metaphysis ( the Klein line ) may intersect less of the epiphysis compared to the normal side. • The epiphysis may appear to be thinner + occur if the slip is posteriorly.

26. Discussion • Radiographic diagnosis: • Early slips difficult to detect on XR. • AP views only detect inferior + medial slips. • Posterior slips seen on lateral views ( but difficult to obtain ). • CT scans helpful to orthopedic surgeon - rarely done in Emergency Department. • MRI scanning not useful.

27. Discussion • Treatment: • Responsibility of Orthopedic surgeon. • Prevent further slipping with internal fixation. • Important to make diagnosis on initial presentation! • Missed diagnosis may worsen slip and the future outcome.

28. Discussion • Complications: • Avascular necrosis - most NB! • Premature osteoarthritis • Chondrolysis - loss of articular cartilage of the hip joint - causes hip to stifffen with permanent loss of motion, flexion contracture + pain.

29. The End

30. References • MEDSCAPE pediatric trauma case studies • Online CME: Pediatrics • Rosen’s Emergency Medicine Online: Pediatric Trauma