http://upload.orthobullets.com/topic/4130/images/windswept pelvis.jpg
http://upload.orthobullets.com/topic/4130/images/at risk.jpg
http://upload.orthobullets.com/topic/4130/images/dislocation.jpg
http://upload.orthobullets.com/topic/4130/images/reimers.jpg
Introduction
  • Cerebral Palsy General 
  • Epidemiology
    • progressive hip subluxation occurs in up to 50% of children with spastic quadriparesis (cerebral palsy)
  • Pathoanatomy
    • subluxation
      • strong tone in hip adductor and flexors lead to scissoring and predisposes to hip subluxation and dislocation
    • dislocation
      • dislocation is typically posterior and superior (>95%)
    • degeneration
      • in time, dysplastic and erosive changes in the cartilage of the femoral head can develop and lead to pain
  • Prognosis
    • grade of hip subluxation is correlated with the GMFCS level 
      • minimal in level I and up to 90% in level V
    • natural history studies have shown that hips will dislocate in the absence of treatment if Reimers index >60-70%
Classification

Stages of Hip Deformity in Cerebral Palsy
Hip at risk
  • Hip abduction of <45° with partial uncovering of the femoral head on radiographs
  • Reimers index <33%
  • Botox A into spastic muscles (age <3) to delay surgery
  • Attempt to prevent dislocation with adductor release, psoas release, hamstring lengthening (age 3-4)
  • Avoid obturator neurectomy 
Hip subluxation
  • Reimers index >33%
  • Disrupted Shenton's line
  • Treat with adductor tenotomy if abduction is restricted.
  • If persistent subluxation, proximal femur varus derotational osteotomy (age 5-6)
  • Do pelvic osteotomies (Dega, Pemberton, Salter, PAO or Chiari) if significant acetabular insufficiency is present
Spastic dislocation
  • Frankly dislocated hip 
  • Reimers index >100%
  • Open reduction with varus derotational osteotomy, + femoral shortening, and pelvic osteotomies
Windswept hips
  • Abduction of one hip with adduction of the contralateral hip
  • Brace adducted hip with or without tenotomy and release abduction contracture of abducted hip
 
Comparison of Spastic Hip Dysplasia and Developmental Dysplasia of the Hip
Factor Spastic Developmental
Findings at birth Hip usually normal Hip usually abnormal
Age at risk Usually normal in 1st year of life; recognized after age 2yr Most often recognized in 1st year of life
Detection Radiographs needed in most cases Physical exam in most cases
Etiology Spastic muscles drive femoral head out of normal acetabulum, pelvic obliquity Mechanical factors (breech), ligamentous laxity, abnormal acetabular growth
Childhood progression Progressive subluxation common Progressive subluxation rare
Natural history Pain in many subluxated/dislocated hips by 2nd or 3rd decade Pain in many subluxated hips by 4th or 5th decade
Acetabular deficiency Usually posterosuperior Usually anterior
Early measures Muscle lengthening Pavlik harness or closed reduction
Missed or failed early measures Hip osteotomies, often without open reduction Closed or open reduction, often without osteotomies (before 18mth of age)
Salvage Castle resection-interposition arthroplasty  Usually total hip arthroplasty
 
Presentation
  • Symptoms
    • hip and/or groin pain
    • difficulty with sitting
    • difficulty with perineal care/hygiene
  • Physical exam
    • unreliable diagnostic assessment if used alone
    • decreased hip ROM
    • pain with hip motion
    • gait difficulty due to lever arm dysfunction
      • hip subluxation/dislocation rare in ambulatory patients
    • thigh length discrepancy (hard to evaluate in setting of adductor contracture) may be seen - sometimes referred to as a "pseudogalleazi sign"
Evaluation
  • Radiographs
    • AP and frog lateral (if possible)
      • Hip abduction of <45° with partial uncovering of the femoral head on radiographs represents an at risk hip
    • Reimers migration index 
      • percent of femoral head with no acetabular coverage
      • most accurate method to identify and monitor hip stability
      • < 33% = at risk
      • > 33% = subluxated hip
  • CT Scan
    • More useful for operative planning rather than diagnosis
    • 3d rendering can help plan acetabular correction
    • CT scanogram can be helpful to measure femoral version if planning a derotational osteotomy
Treatment
  • Nonoperative
    • observation
      • mild cases
    • Physical therapy never shown to prevent hip subluxation
    • Abduction bracing alone does not reduce dislocations and may cause windswept deformity
  • Operative - soft tissue procedures
    • Hip adductor and psoas release with abduction bracing
      • indications 
        • children < 4 years and Reimers index > 40% 
          • this is one exception to the general rule of avoiding surgery in CP patient < 3 years of age
          • Consider for "at risk" hips, too (see chart above)
        • any evidence of progressive subluxation if less than 8-year-old
      • contraindicated in children > 4 years if bony reconstruction is needed due to the severity of the disease
  • Operative - reconstuctive procedures
    • proximal femoral osteotomy with shelf-producing (Dega) osteotomy and soft-tissue release
      • indications
        • children > 4 years old or Reimers index > 60% 
      • best to treat all pathology at single stage if the patient has a severely dysplastic CP hip
  • Operative - salvage procedures
    • valgus support osteotomy (femoral head resection + valgus subtrochanteric femoral osteotomy (e.g McHale Technique)  
      • indication
        • salvage technique for symptomatic and chronically dislocated hips in cerebral palsy
    • Castle resection-interposition arthroplasty
      • indications
        • chronically dislocated hips, especially in the adult CP population
        • unable to walk, stand to transfer (GMFCS 5)
    • total hip arthroplasty
      • indications
        • ambulatory patients and wheelchair bound who can stand to transfer
      • results
        • 85% 10 year survival in CP patients
    • hip arthrodesis
      • indications
        • young patients
        • ambulatory patients and wheelchair bound who can stand to transfer
    • Girdlestone procedure
      • indications
        • no longer performed because uniformly causes pain
          • caused by lack of interposition of soft tissue between cut femur and acetabulum leads to proximal femoral migration
Techniques
  • Hip adductor and psoas release with abduction bracing
    • goals of treatment
      • prevent hip subluxation and dislocation
      • maintain comfortable seating
      • facilitate care and hygiene
      • >45 degrees of hip abduction after releases
    • technique
      • begin with tenotomy of the adductor longus, sequentially release gracilis and adductor brevis as needed
      • release the psoas tendon either at the level of the insertion (non-ambulatory patients) or proximally at the pelvic brim in the myotendonous junction (ambulatory patients)
    • complications
      • careful of obturator nerve if brevis release is needed
        • a neurectomy of the obturator nerve can cause an abduction contraction
  • Proximal femoral osteotomy and soft-tissue release, possible acetabular osteotomy
    • goals of treatment
      • hip containment in the severely dysplastic hip with progressive subluxation
      • single-stage osteotomies may have improved outcome
    • technique
      • shortening varus derotational osteotomy to correct increased valgus and anteversion
      • may need pelvic osteotomy to correct acetabular dysplasia; the indications to combine pelvic osteotomy remains controversial
      • may need salvage acetabular procedures to obtain coverage once triradiates are closed (i.e. Chiari, Dega/Shelf) 
        • acetabular undercoverage is typically postero-superior (as opposed to anterosuperior in DDH), and osteotomies should provide more lateral coverage
  • Valgus support osteotomy (femoral head resection + valgus subtrochanteric femoral osteotomy (e.g McHale Technique)  
    • non-anatomic arthroplasty that relieves pain and improves hip abduction
    • technique
      • anterolateral approach to remove femoral head and neck leaving ligamentum teres attached to acetabulum
      • perform a closing wedge subtrochanteric valgus-producing osteotomy and fix with lateral plate
      • attach ligamentum teres to psoas tendon or anterior capsule
      • the lesser trochanter will articulate with the dome of the acetabulum
    • successfully relieves pain despite non-anatomic articulation
  • Castle resection-interposition arthroplasty
    • technique
      • resect proximal femur at the level of lesser trochanter (note the difference from a Girdlestone)
      • oversew vastus over cut proximal femoral end
      • oversew abductors, psoas and hip capsule over acetabulum
      • this interposes a large mass of soft tissue between the acetabulum and proximal femur
Complications
  • Osteonecrosis of femoral head
    • incidence 1-11%
  • Heterotopic Ossification
    • prevention
      • radiation on the second or third postoperative day more effective than anti-inflammatory medications
  • Insufficiency factures
    • incidence
      • ranges from 4-29%
    • may be seen in distal femur following postoperative Spica casting
  • Abduction contracture
    • may occur with neurectomy of anterior branch of obturator nerve during adductor releases
 

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Questions (2)

(OBQ12.201) A 15-year-old, non-ambulatory patient with cerebral palsy who is unable to maintain an upright head position against gravity, has pain while sitting in his wheelchair. An AP pelvis radiograph is shown in Figure A and attempted frogleg lateral view in Figure B. A preoperative CT scan (Figure C) demonstrates significant femoral head flattening. What is the most accurate Gross Motor Function Classification System level, and what is the most appropriate surgical intervention? Review Topic

QID:4561
FIGURES:
1

GMFCS V: Open reduction with varus derotational osteotomy, femoral shortening, psoas release, and pelvic osteotomy

28%

(567/2029)

2

GMFCS I: Hip adductor and psoas release plus abduction bracing

5%

(101/2029)

3

GMFCS V: Open reduction with varus derotational osteotomy

8%

(170/2029)

4

GMFCS V: Proximal femoral resection

54%

(1094/2029)

5

GMFCS I: Open reduction with femoral varus derotational and pelvic osteotomy

4%

(82/2029)

Select Answer to see Preferred Response

PREFERRED RESPONSE 4

This patient would classify as a Gross Motor Function Classification System Level (GMFCS) V. Proximal femoral resection is indicated in a nonambulatory patient with cerebral palsy that has pain while sitting in his wheelchair.

The Gross Motor Function Classification System Level (GMFCS) is commonly used for cerebral palsy. Level V is characterized by physical impairment which restricts voluntary control of movement and the ability to maintain antigravity head and trunk postures. Children have no means of independent mobility and are transported. Hip instability is uncommon in the ambulatory CP patient, but it is very common in the nonambulatory CP patient. 50% to 75% of dislocated hips will become painful in CP patients.

Muthusamy et al. performed a Level 4 review of 27 CP patients that were followed for nearly 8 years following a proximal femoral resection. They found that hip pain, range of motion, activities of daily living, and quality of life after surgery were all improved.

Leet et al. also conducted a Level 4 review of patients that underwent femoral head resection with traction or a McHale procedure (femoral head resection and valgus osteotomy). They found that the McHale group had a shorter length of stay in the hospital, less postoperative superior migration, and lower surgical and medical complications. However, both groups had increased sitting tolerance and decreased pain, and overall satisfaction with the surgical outcome.

Figure A demonstrates a dislocated left hip. Illustration A shows the Gross motor function classification system (GMFCS) for patients aged 6-12 years with cerebral palsy. Illustration B demonstrates the Mchale procedure consisting of femoral head resection and valgus osteotomy.

Incorrect Answers:
Answer 1, 3, and 5: Open reduction is relatively contraindicated in the setting of a flattened head. Reducing a degenerative femoral head may cause hip pain.
Answer 2: Soft tissue releases and bracing would be unlikely to obtain a sustainable reduction.

ILLUSTRATIONS:

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(OBQ09.208) The parents of a wheelchair-bound 8-year-old boy with cerebral palsy present with difficulty during diaper changes and with hygiene care. His physical exam demonstrates 5° of hip abduction on the left hip and 15° on the right. An AP pelvis radiograph is shown in figure A. What is the most appropriate treatment? Review Topic

QID:3021
FIGURES:
1

Bilateral botox injections and physical therapy

16%

(97/617)

2

Nighttime Pavlik harness

2%

(10/617)

3

Bilateral abductor release and valgus femoral osteotomies

12%

(74/617)

4

Bilateral adductor release, varus femoral osteotomies and acetabuloplasties

66%

(410/617)

5

Observation with repeat radiograph in 6 months

4%

(24/617)

Select Answer to see Preferred Response

PREFERRED RESPONSE 4

Children with spastic cerebral palsy develop hip subluxation as the result of long term muscle imbalance. Subluxation can progress to hip dislocation with resulting difficulties in seating, hygiene or personal care, and/or hip pain. The patient has bilateral dislocated/near dislocated hips with acetabular dysplasia.

Flynn and Miller provide a thorough review of hip disorders in patients with cerebral palsy including etiology, physical exam and treatment guidelines. Recommendations included hip reconstruction for children over 4 years of age with severe subluxation or dislocation if severe degenerative changes are absent. Hip reconstruction consists of a one-stage soft-tissue lengthening with varus derotational femoral osteotomy and possible acetabuloplasty.

Spiegel and Flynn also have provided a comprehensive review of hip dysplasia in patients with cerebral palsy. The article discusses early intervention to prevent complications associated with subsequent hip dislocations. Surgical intervention in patients older than 4 years with hip dislocations was once again hip reconstruction with soft-tissue lengthening, femoral osteotomies and acetabuloplasties in patients in patients with marked acetabular abnormalities.


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