COXA MAGNA DEFORMITY
B. J. Manaster, MD, PhD, FACR
DIFFERENTIAL DIAGNOSIS
Common
Developmental Dysplasia Hip (DDH)
Less Common
Slipped Capital Femoral Epiphysis (SCFE)
Legg-Calvé-Perthes (LCP)
Rare but Important
Septic Hip
Hip/Femur Trauma
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Coxa magna: Short, broad femoral head sitting on short, broad femoral neck
Results in limb length discrepancy
Relatively proximal displacement of greater and lesser trochanters
Coxa magna is secondary to insult to femoral head or epiphysis
Helpful Clues for Common Diagnoses
Developmental Dysplasia Hip (DDH)
Lack of coverage of femoral head during development due to deficient acetabulum
Without coverage, head cannot develop spherical shape
Head becomes short, broad
With head and neck shortening, limb becomes short, with proximal displacement of both trochanters
Congenital abnormality
Severe DDH develops coxa magna
Subtle DDH does not show coxa magna but seen as ↓ center-edge angle of Wiberg
Hint: Shallow acetabulum distinguishes coxa magna of DDH from other etiologies of coxa magna
Helpful Clues for Less Common Diagnoses
Slipped Capital Femoral Epiphysis (SCFE)
Femoral capital epiphysis slips medially and posteriorly
As head slips, appears short and broad, on short and broad neck
Most frequently occurs 8-14 years of age
Hint: Position of femoral head on neck and a normal acetabulum distinguish coxa magna of SCFE from other etiologies
Legg-Calvé-Perthes (LCP)
Avascular necrosis of femoral head in child, generally 4-8 years of age
Flattening of head leads to coxa magna deformity
Hint: Head remains centered on femoral neck and acetabulum is normal, distinguishing this etiology of coxa magna from others
Helpful Clues for Rare Diagnoses
Septic Hip
Chronic hip infection during childhood
Hyperemia results in overgrowth of femoral head and neck
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
