1. Slipped Capital Femoral Epiphysis

2. Introduction SCFE = misnomer neck displaces relative to the epiphysis
Usually, upward & anterior of neck
Rapid growth, weakening of physis, shearing stresses
                                                                                              

3. Femoral head in contact
with acetabulum
Femoral shaft and neck
rotate externally
Head moves posteriorly
Neck moves cephalad

4. Historical Perspective
? Pare first described SCFE
? Muller 1889
Schenkelhalsverbiegungen im Jungesalter
“bending of the femoral neck in adolescence”
Whitman osteotomies
Boyd stabilization with pins

5. Incidence/Epidemiology
Varies according to race, sex, geography
Estimated 2 per 100,000
Males > females left > right
During max skeletal growth
boys years, avg 14
girls years, avg 12
Bilateral 17-80% reported
most studies show 20-25%
 black males, eastern US
Varies less than1-7/100,000 depending on race and geographic location
Rarely occurs in girls after menarche

6. Classification Temporally, according to onset
acute, acute-on-chronic, chronic
Functionally, according to ability to WB
stable, unstable
Morphologically, according to extent of displacement
Extent of displacement estimated by measurement on XRAY or CT

7. Temporal Classification Acute
Sudden, dramatic, fracture-like episode
Prodromal symptoms for 3 weeks or less
Trauma too trivial to cause SH1
X-rays- little or no neck remodeling
AVN frequent, 17-47%
**R/O true Salter-Harris Type 1**
True SH1 will not have prodrome, severe trauma, often associated with concomitant hip dislocation

8. Temporal Classification Chronic
Most frequent form
Few months of vague groin/thigh pain, limp
X-rays- remodeling of neck
Can be missed as symptoms as often minor

9. Temporal Classification Acute-on-chronic
Prodrome for > 3 months with sudden exacerbation of pain
X-rays- displacement beyond remodeling

10. Functional Classification
Stable
able to WB on presentation
Unstable
not able to WB
Preferred classification
Clinically meaningful
different prognosis

11. Morphologic Classification
Degree of displacement of epiphysis on neck
Southwick femoral head-shaft angle
mild < 30°
moderate 30-60°
severe > 60°
(normal 145° on AP)
CT more accurate, not routinely used

12. Etiology Often unknown
Majority are normal by current endocrine work-up
Endocrine
Mechanical

13. Etiology Mechanical Factors
Predisposing features:
-thinning of perichondral ring complex
-retroversion of femoral neck
-change in inclination of prox femoral
physis relative to femoral neck/shaft
Blount’s disease, peroneal spastic flatfoot, Legg-Calve-Perthes disease
Cadaver studies

14. Etiology Mechanical Factors 1) Perichondral Ring Thinning
Fibrous band that encircles physis at cartilage-bone interface
Acts as limiting membrane, mechanical support to physis
Thins rapidly with maturation  strength

15. Etiology Mechanical Factors 2) Retroversion of Femoral Neck
Relative or femoral retroversion
? Physis more susceptible to AP shearing forces
3) Inclination
Increased slope of proximal femoral physis on both affected and non-affected sides

16. Etiology Endocrine Factors
Long suspected
Obesity, hypogonadal males (adiposogenital syndrome), growth spurt
No screening unless clinical suspicion
Known association with:
-hypothyroidism (treated or not)
-conditions with GH administration
-CRF
Prev pelvic XRT, Rubinstein-Taybi syndrome, Klinefelter’s syndrome, 1° hyperparathyroidism, panhypopituitism assoc with intrancranial tumours

17. Etiology Endocrine Factors
Hypothyroidism
prior to or during Rx
GH deficiency
during or after Rx
Bilateral slips….prophylactic pinning should be strongly considered

18. Endocrine Factors CRF
Thought to be due to uncontrolled 2° hyperparathyroidism
Goal of Rx: control hyperparathyroidism within 2/12 of slip sx
If not successful  surgical Rx
Monitor until skeletal maturity due to high incidence of slip progression

19. Pathology
Do not support or exclude endocrine or mechanical etiologic actors
? Changes 2° physeal disruption or endocrine influence
Weiss & Sponseller 1990
Normal iliac crest physeal Bx in pts with SCFE

20. Pathology Gross
Periosteum stripped from ant/inf surface of femoral neck
Area btw neck & post periosteum fills with callus & ossifies
Anterosuperior neck forms “hump”, can impinge on acetabular rim (remodel)
Acute slips will have hemarthrosis

21. Pathology Microscopic
Howorth slips treated open
“Preslip” stage
-widened physis without displacement
-edematous synovial membrane,
periosteum, capsule
Thicker proliferative & hypertrophic zones
- chondrocytes, organized in clumps

22. Clinical Picture Stable SCFE
History
vague or dull pain (groin, anteromedial thigh, knee)
Exacerbated by activity
Weeks to months
Physical Exam
Antalgic limp with  ER
Thigh atrophy
 hip ROM- loss of IR,ABD, flexion
Obligate ER with flexion, pain at extreme IR
Hip flexion contracture (chondrolysis)
No strenuous maneuvers, i.e. hopping/squatting

23. Clinical Picture Unstable SCFE
History
Sudden onset of severe pain
Minor fall or twisting injury
Physical Exam
Held in ER
Refusal to move hip
Moderate shortening

24. **Always examine hips in any child with knee pain
Matava et al. (1999) 106 slips
15% knee/distal thigh pain only
Carney (1991) 46% distal thigh/knee as only
presenting complaint
**Always examine/x-ray contralateral side
20% have evidence on initial presentation

25. Diagnostic Imaging Plain Radiographs
Often only imaging needed
Earliest sign = physeal widening/irregularity
Klein’s Lien (AP)
- line tangential to superior femoral neck
will intersect lateralmost portion
- with SCFE,  overlap or none =Trethowan’s
sign
Steel’s metaphyseal blanch sign (AP)
crescent-shaped area of density

26. Metaphyseal blanching

27. Diagnostic Imaging CT -useful in mgmt -confirm physeal closure
-severity of deformity
MRI
-detection of AVN
Bone Scan
- uptake for AVN
- uptake both sides for chondrolysis

28. Treatment
Goal: stabilize the epiphysis to the femoral neck to prevent further slippage
In situ fixation/pinning
Bone graft epiphysiodesis
Primary osteotomy
Spica Cast
Treatment Choice depends on type pf slip, severity, surgeon preference
                                                                                              

29. Treatment Initial Management
To radiology in wheelchair or stretcher
**Identify unstable slips**
Do not attempt frog-leg lateral in unstable slips
Admit with strict bedrest, until definitive Rx

30. Treatment Stable SCFE In Situ Pinning/Fixation
Many different philosophies
number/type of implant, physeal closure, position of screws
Current standard: one cannulated screw into femoral epiphysis from base of anterior neck for stable slips.
Two screws considered for unstable slips (additional stability, rotational control)

31. In Situ Fixation Fracture table Avoid excessive IR & manipulation
Guide-wire for screw placement
Ideal placement of screw is as close to centre of epiphysis & as  to physis as possible
**epiphysis is posterior, entry point must be at base of neck and screw directed posteriorly into centre
Avoid posterior femoral neck
                                                  
                                                  

32. In Situ Fixation

33. In Situ Fixation Post-operative Management
Protected partial weight-bearing with crutches for 6 weeks
No sports for 3 months
Clinical exam + x-rays every 3-6 months until skeletal maturity

34. In Situ Fixation Advantages Minimal scarring
No need to manipulate limb during surgery
Disadvantages
Difficult lateral view
Difficult guidewire placement if obese
Screw-related complications
perforation into joint, loss of fixation, failure,

35. Bone Graft Epiphysiodesis
Portion of residual physis is removed by drilling and curettage
Dowel or “peg” of autologous bone graft inserted across femoral neck
Supplementary internal fixation or cast for unstable slips
Indications
Stable slip that has progressed despite fixation
Severe slip

36. Bone Graft Epiphysiodesis

37. Bone Graft Epiphysiodesis

38. Primary Osteotomy Goals:
Correct symptomatic loss of motion, esp. flexion and IR
Improve biomechanics for healing
Improve longevity of the hip

39. Primary Osteotomy Dunn Procedure
Anterosuperior wedge of superior femoral neck, including residual physis
Femoral epiphysis is reduced on neck without tension
Secured with screws or pins
Best anatomic restoration
High risk of AVN

40. Primary Osteotomy Base-of Neck
Kramer & Barmada
Expose neck intra or extracapsularly
Anterosuperiorly based wedge from base of neck
Apex of wedge may be extracapsular posteriorly
Reduction and punning as in Dunn
Lower AVN risk

41. Primary Osteotomy Intertrochanteric
Southwick
Based on head-shaft angle
Anterolaterally based intertrochanteric
wedge
Corrects extension/varus deformity by flexion/abduction of distal fragment,
IR as needed
Low AVN risk
Chondrolysis 10-40%

42. Treatment Spica Cast Little indication for immobilization alone
Often used as adjunct to
surgical treatment
May be used if surgery
contraindicated or other treatments
have failed

43. Anterior & Valgus Slips
Valgus slip = superior and posterior displacement
Valgus  adduction, flexion
Anterior  extension, ER
Same treatments
watch for femoral neurovascular bundle
with valgus slip

44. Prophylactic Pinning of Contralateral Hip
20% present with bilateral involvement
Additional 25% will have symptomatic contralateral slip
Most develop within 6 months
Ongoing debate
Consider in CRF (95% bilateral), endocrinopathy-related slips, younger patients
If not done, educate parents and monitor every 6 months

46. Complications Chondrolysis
Incidence and etiology unknown (5-7%)
Stiffness, persistent groin or thigh pain
Painful ROM, flexion contracture
RF: pins, cast immobilization, severe, chronic
X-rays:  joint space
 50% loss or  3mm
Usually 6 weeks to 4 months after Rx, max within 6-12 months of onset
Treatment
Removal hardware
Supportive – activity modification, physio, NSAIDs (arthroplasty)

47. Complications AVN Most severe complication
RF: unstable (47%), severe, iatrogenic
Evident a few weeks to 1 year after slip
Total or partial
Poor long-term prognosis
Treatment
Prevention
avoid reduction, manipulation, Rx delay
Educate family & patient
Delay osteotomy until healed

48. AVN

49. Long-term Outcomes
Risk of OA directly related to severity of residual deformity
Significant potential for remodeling
delay treatment until skeletal maturity
Evidence that osteotomy alters the development of OA is lacking