Coxa Vara

 

 

Definition

 

Deformity of proximal femur with neck-shaft angle <110°

 

Issues

 

Limp / Trendelenberg gait

Stress fractures

Early osteoarthritis

 

Classification   

 

Developmental

 

Acquired

- Rickets / Hypothyrodism / Renal osteodystrophy / Hyperparathyroidism

- Perthes disease / SCFE

- infection

- trauma / early closure physis

 

Dysplasia

- MED / SED                 www.boneschool.com/multiple-epithelial-dysplasia

- Achondroplasia           www.boneschool.com/achondroplasia

- Fibrous Dysplasia        www.boneschool.com/fibrous-dysplasia

 

Achondroplasia                                                                 Multiple epithelia dysplasia

 

Developmental Coxa Vara

 

Epidemiology

 

Rare

Male = female

Bilateral in 1/3

 

Etiology

 

Unknown 

 

Clinical

 

Abnormal gait

Trendelenberg gait

Reduced ROM

 

Xray

 

 

Varus femoral neck	Inverted Y	Hilgenreiner's epiphyseal angle
Neck-shaft angle < 125°   Normal is 150° in infant	Inferior sclerotic metaphyseal triangle   Pathognomonic of developmental	Angle between Hilgenreiner's & physeal line   Normal < 25°

 

 

Management

 

Management based on Epiphyseal Angle

 

< 45 degrees	45 - 60 degrees	> 60 degrees
Unlikely to progress	Observe	Surgery
Observe	Surgery if progresses

 

Operative management

 

 

Valgus derotation subtrochanteric osteotomy

- overcorrect to 150˚

- epiphyseal angle < 40^o

- correct anteversion to 10^o

 

Results

 

Audisio et al J Orthop 2024

- systematic review of proximal femoral osteotomy in 192 hips with coxa vara

- success rate was 89%

- loss of correction 11%)

- deep infection 1%

- revision surgery 9%

 

Technique

 

 

Synthes Pediatric Proximal Femur Offset Plate Technique PDF

 

POSA proximal femoral osteotomy for coxa vara video

 

Lateral approach

- elevate / L shaped detachment of vastus lateralis

- mark distal and proximal with drill hole for rotation

- K wire in central head

- sub-trochanteric osteotomy with saw

- application of 150^o Synthes offset locking plate

- internal rotation of about 20° at time of osteotomy

 

May require

- adductor tenotomy

- femoral shortening

- greater torchanter transfer

 

Complications

 

 

Loss of correction  - related to undercorrection

 

Premature physeal closure - related to increased pressure 

 

Greater trochanter overgrowth  - associated with premature physeal closure

 

Acetabular dysplasia  - associated with premature physeal closure and undercorrection