Purpose

Our goal was to assess the prevalence of ipsilateral distal femoral osteochondritis dissecans (OCD)-like lesions in children with Blount disease, including factors associated with this finding.

Materials and methods

Characteristics of patients with an OCD-like lesion on an imaging study [(X-ray and/or magnetic resonance imaging (MRI)] were compared with those without such a finding.

Results

Over a 12-year period, 6/63 (10%) skeletally immature patients (9/87 limbs) with Blount disease had an OCD-like lesion visible on plain radiographs. Based on available MRI, 7/37 (19%) patients or 10/53 (19%) limbs had an OCD-like distal femoral lesion. All lesions were noted in the posterior third of the weight-bearing portion of the medial femoral condyle with intact overlying articular cartilage. All patients with OCD-like lesions were followed for an average of 1.9 years (range: 1-2.6 years), and complete radiographic resolution of lesion was noted in 7/9 limbs (78%). There was no association of the presence of OCD-like lesion with early- vs late-onset disease, gender, age at imaging, laterality, magnitude of deformity [mean mechanical axis deviation (MAD) 63.3 vs 71.9 mm], mean mechanical lateral distal femoral angle (mLDFA; 91.3 vs 89.7°), and mean medial proximal tibial angle (MPTA; 71.7 vs 71.8°). Children with an OCD-like lesion tended to have a lower mean body mass index (BMI; 21 vs 36, p = 0.003).

Conclusion

The overall prevalence of OCD-like lesions in the medial femoral condyle in children with Blount disease lesions is 10% using plain radiographs and at least 19% on MRI. Based on the numbers available, we were unable to demonstrate any associations between the presence of such lesions and the patient's age, gender, or magnitude of varus deformity. Further research is needed to fully ascertain the aetiology and natural history of these benign appearing osteochondral imaging findings in children with Blount disease. Our current data support that these lesions do resolve with time and that no surgical intervention targeted at the femoral OCD-like lesion is warranted.

Level of evidence

Diagnostic study Level III.

How to cite this article

Edobor-Osula F, Wenokor C, Bloom T, et al. Ipsilateral Osteochondritis Dissecans-like Distal Femoral Lesions in Children with Blount Disease: Prevalence and Associated Findings. Strategies Trauma Limb Reconstr 2019;14(3):121-125.