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In children under the age of five, is bracing as effective as surgery at correcting Blount's disease (tibial varum) and preventing future musculoskeletal impairments?

Kristin Hamrick & Brandy HirschBellarmine University DPT Class of 2015

Background

Blount’s Disease

Uncommon growth disorder usually seen in children and adolescents as a result of internal rotation of the proximal tibia immediately below the knee Although Blount’s disease is idiopathic, biomechanical factors are still considered to be a large contributor of the pathological cycle [7]

Presents as excessive varus angulation at the knee Progressive (gets worse, not better) [1]

3 Categories [2]

1. infantile tibia vara: before 4 years of age• Typically bilateral• MD angle > 16 degrees• 5x more common than adolescent form

2. juvenile tibia vara: between 4-10 years3. adolescent tibia vara: after 10 years

• Typically unilateral

Associated clinical characteristics [1,3,6]

• Early walkers• Obese• African Americans• F > M• M > F in adolescent

Treatment depends on age and severity: [1]

• Spontaneously resolves by age 3• Bracing/orthotic• Surgery

Typical treatment course: [1]

Observe bracing osteotomy last resort

Surgical Intervention

Non-operative Intervention Outcomes & Conclusion

Clinical Relevance

Literature Cited

Theory: shifting the pressure from the medial surface of the tibia to the lateral surface will cause a pull on the medial aspect of the knee, increasing joint space and allowing the medial tibia to grow, resulting in correction. [7]

Indications: [3,7]

• Children < 3 years (especially if unilateral)• Stages I-II• MD angles > 16 degrees• MD angles between 9-16 degrees with presence of ligamentous laxity or obesity• If successful, improvement should occur in 1 year• Bracing must continue for approximately 2 years for resolution of bony changes

Risk factors for failure of bracing: [3,8]

• Obesity• Varus thrust• > 3 years at initial treatment• Bilateral disease• Stage III or greater deformity

Gold standard: Corrective Osteotomy Procedure: cut tibia just below knee joint to correct alignment and use plate or external device to facilitate bone healing in a straightened position Goals: relieve pain and correct limb alignment Not recommended under age 2 Indications: [1,2]

• Severe cases (Langenskiöld stage III or IV)• Bracing/orthotics fail• Unresolved deformity by age 4• Adolescent tibia vara In the infantile population, the osteotomy must be performed while sparing both the tibial physis and apophysis of the tibial tubercle [3]

Surgery: Potential motor weakness and/or sensory deficits secondary to damaged fibular nerve [5]

Not recommended before age 2 [5]

Definitive surgery for infantile Blount's disease is most successful before age 5 to prevent recurrence [2]

The use of external fixation has better outcomes than internal fixation [2]

Good prognosis if: under age 3, normal weight, Langenskiold stage I or II, ADA angle < 18 [6]

MPS most significant : MPS angle = or < 59 degrees [6]

Bracing: Bracing appears to be effective in stages I & II infantile Blount's disease, specifically in cases with unilateral involvement [3]

Children with bilateral disease or age greater than 4 are more likely to require surgical intervention [3]

Research suggests that daytime, ambulatory bracing can correct tibial vara in patients < 3 years of age [7]

Overall, outcome depends on patient’s age and severity of deformity at the time of intervention [3]

Ultimately, if implemented early, bracing is an effective and less invasive treatment for Blount’s disease, especially infantile form stages I & II [8]

Classification

Langenskiold Classification – six roentenographic stages depending on degree of skeletal maturation and upper end bone development [4]

I: under 3 yrs., medial and distal beaking of metaphysis with irregularity of entire metaphysis II: age 2.5-4 yrs., sharp anteromedial depression and ossification line of wedge-shaped medial metaphysis III: age 4-6 yrs., deepening of metaphyseal beak IV: 5-10 yrs., enlargement of epiphysis V: 9-11 yrs., cleft in epiphysis, appearance of double epiphysis VI: 10-13 yrs., closure of medial proximal tibial physis

Catonne Classification – six stages based on progressive radiographic change [4]

a.I: 2-3 yrs., asymmetry of tibial epiphysisb.II: 3-5 yrs., sloped epiphysis & uneven metaphyseal shapec.III: 5-8 yrs., vertical medial epiphysis and metaphysis, medial calcifications

a.IV: 8-11 yrs., small medial bony bridgeb.V: medial bony bridgec.VI: adult aspect of physis

Bracing with KAFO KAFO: above knee, ambulatory orthotic that: [7]

• maintains full extension• places isolated valgus force on proximal medial tibia to unload bone• controls knee lateral shift• allows DF but limits PF to 90°• prevents hyperextension of knee• can be released at the knee for sitting

The key to successful treatment of Blount’s disease in the clinic is early identification of the type (i.e. infantile) and stage of the disease. Understanding what treatment options are indicated for each stage will help clinicians make the most appropriate and conservative choice for each patient. Recognizing the time frames when bracing or surgery are most successful is crucial in correcting Blount’s disease and preventing further musculoskeletal impairments.

1. Boyce PT, EdD, OCS, ECS. Bellarmine University. (2009). Pediatric Orthopedics. [PowerPoint]. Retrieved by blackboard.bellermine.edu

2. Davidson R.S., Shirley E.D. Surgical Management of Blount's Disease. Inc: Wiesel S.W. Operative Techniques in Orthopaedic Surgery. Volume II. Lippincott Williams & Wilkins; 2012: Chapter 30.

3. Doyle BS, Volk AG, Smith CF. Infantile Blount disease: long-term follow-up of surgically treated patients at skeletal maturity. J Pediatr Orthop. Jul-Aug 1996;16(4):469-76. Medline.

4. Ducou le Pointe H, Mousselard A, Rudelli A, Montagne J.P, Filipe G. Blount's disease: magnetic resonance imaging. Pediatric radiology. 1995;25;12-14. http://link.springer.com/article/10.1007%2FBF02020831#page-1 Accessed November 15, 2013.

5. Jahangiri FR. Multimodality neurophysiological monitoring during tibial/fibular osteotomies for preventing peripheral nerve injuries. The Neurodiagnostic journal. 2013;53(2):153–68. Available at: http://www.ncbi.nlm.nih.gov/pubmed/23833842

6. Kaewpornsawan K, Tangsataporn S, Jatunarapit R. Early proximal tibial valgus osteotomy as a very important prognostic factor in Thai children with infantile tibia vara . Journal of the Med Association of Thailand. 2005;5:72-79.

7. Marshall JG. Orthotic Treatment of the Toddler with Bowed Legs. Pediatric Portal. Nov 2010; 4-6. O&P Business News.

8. Orthotic Treatment of Infantile Tibial Vara. Medscape Orthopedics. 1999; 3(6): www.medscape.com

[7]

Bilateral [1]Unilateral [1]

[4]

Importance of Intervention

Some musculoskeletal impairments can be prevented by early identification & treatment of Blount’s disease, including: arthritis & joint degeneration foot deformities: excessive pronation/medial collapse weakened ligaments & knee instability medial knee pain gait abnormalities