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Blount's Disease
SectionMusculoskeletal system
Case TypeClinical Cases
Authors
Gorianov V, Bayne GJ, Clarke NMP.
Department of Children's Orthopaedics, Southampton General Hospital
Hampshire, United Kingdom
Connected authors
6 years, female
Clinical History
This 6 year old girl presented with bilateral mild knee discomfort and bowing of the legs.
Imaging Findings
This six year old girl presented with long standing mild knee discomfort and deteriorating genu varum deformity. Initial radiographs demonstrated varus deformity bilaterally with significant medial metaphyseal beaking in keeping with Blount's disease. The varus deformity progressed despite management with Knee-Ankle-Foot Prosthetic braces. Subsequent radiographs showed increasing fragmentation of the proximal left tibial metaphysis medially. The patient underwent bilateral medial femoral 8-plate insertion and proximal tibial osteotomies. After immobilisation in plaster post-operatively she recovered well.
Discussion
Blount's Disease was described by Walter Putnam Blount, an American orthopaedist, in 1937. He reported 13 children with a form of bow legs which he termed "osteochondrosis deformans tibiae". The condition was the consequence of deformation of the upper medial tibial epiphyses and metaphyses but the aetiology was unknown.
The differential diagnosis of Blount's Disease includes physiological bowing, congenital bowing, rickets, Ollier's Disease, trauma, osteomyelitis and metaphyseal chondroplasia. Unlike in Blount's disease where the bowing occurs immediately below the medial metaphyseal beak producing a metaphyseal-diaphyseal angle greater than 11 degrees, in physiological bowing the deformity is the result of a gradual curve involving both the femur and tibia. With congenital bowing the angulation often occurs in the middle portion of the tibia with a normal appearing distal femur and proximal tibia. Olliers disease can produce tibial bowing but is distinguished on radiographs by the presence of enchondromas. Trauma can injure the proximal tibia growth plate which may produce a deformity resembling tibia vara, as can osteomyelitis. In metaphyseal chondroplasia, multiple metaphyseal deformities are seen, as is short stature.
Magnetic resonance imaging (MRI) can be useful for the diagnosis of difficult cases. It's use is limited in that the patient cannot be in the erect position for the procedure (which may mask the severity of deformity).
It affects toddlers as well as older children. Bow-leggedness is the most common presentation. Physiological bowing of the knees is common in toddlers, but if it has not corrected by the age of two years the possibility of Blount's disease should be explored. It is often associated with internal tibial torsion and in-toeing. The incidence of Blount's disease is higher with female sex, African-American race, obesity, and early age of walking. Between 9-43% of affected children have a positive family history.
The aetiology of Blount's remains unclear, although it is believed that the interplay of genetic, environmental and mechanical factors is responsible. Once present, the bow-leggedness is self-perpetuating by placing even greater stress on the medial portion of the epiphysis. This will progress without early treatment.
The differential diagnosis of Blount's Disease includes physiological bowing, congenital bowing, rickets, Ollier's Disease, trauma, osteomyelitis and metaphyseal chondroplasia. Unlike in Blount's disease where the bowing occurs immediately below the medial metaphyseal beak producing a metaphyseal-diaphyseal angle greater than 11 degrees, in physiological bowing the deformity is the result of a gradual curve involving both the femur and tibia. With congenital bowing the angulation often occurs in the middle portion of the tibia with a normal appearing distal femur and proximal tibia. Olliers disease can produce tibial bowing but is distinguished on radiographs by the presence of enchondromas. Trauma can injure the proximal tibia growth plate which may produce a deformity resembling tibia vara, as can osteomyelitis. In metaphyseal chondroplasia, multiple metaphyseal deformities are seen, as is short stature.
Magnetic resonance imaging (MRI) can be useful for the diagnosis of difficult cases. It's use is limited in that the patient cannot be in the erect position for the procedure (which may mask the severity of deformity).
It affects toddlers as well as older children. Bow-leggedness is the most common presentation. Physiological bowing of the knees is common in toddlers, but if it has not corrected by the age of two years the possibility of Blount's disease should be explored. It is often associated with internal tibial torsion and in-toeing. The incidence of Blount's disease is higher with female sex, African-American race, obesity, and early age of walking. Between 9-43% of affected children have a positive family history.
The aetiology of Blount's remains unclear, although it is believed that the interplay of genetic, environmental and mechanical factors is responsible. Once present, the bow-leggedness is self-perpetuating by placing even greater stress on the medial portion of the epiphysis. This will progress without early treatment.
Differential Diagnosis List
Blount's Disease
Final Diagnosis
Blount's Disease
Case information
| URL: | https://www.eurorad.org/case/6853 |
| DOI: | 10.1594/EURORAD/CASE.6853 |
| ISSN: | 1563-4086 |
Figure 2
Figure 1
Presentation radiograph showing bilateral bowing of the legs with medial metaphyseal beaking in the tibia
Figure 3
Figure 3
Right leg Post operative AP radiograph with 8 plate on medial distal femoral epiphysis and proximal tibial osteotomy
Right leg Post operative lateral radiograph with 8 plate on medial distal femoral epiphysis and proximal tibial osteotomy
Left leg Post operative AP radiograph with 8 plate on medial distal femoral epiphysis and proximal tibial osteotomy
Left leg Post operative lateral radiograph with 8 plate on medial distal femoral epiphysis and proximal tibial osteotomy
Figure 1
Presentation radiograph showing bilateral bowing of the legs with medial metaphyseal beaking in the tibia
Figure 3
Right leg Post operative AP radiograph with 8 plate on medial distal femoral epiphysis and proximal tibial osteotomy
Right leg Post operative lateral radiograph with 8 plate on medial distal femoral epiphysis and proximal tibial osteotomy
Left leg Post operative AP radiograph with 8 plate on medial distal femoral epiphysis and proximal tibial osteotomy
Left leg Post operative lateral radiograph with 8 plate on medial distal femoral epiphysis and proximal tibial osteotomy