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Ulnar focal cortical indentation: a previously unrecognised form of ulnar dysplasia
K Kazuki1, K Hiroshima, K Kawahara
1Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan. kkazuki@med.osaka-cu.ac.jp
Insights
A previously unrecognized forearm deformity caused by focal cortical indentation of the ulna has been identified in children. Surgical intervention involving ulnar lengthening and osteotomy showed promising results in correcting the deformity.
Area of Science:
- Orthopedic surgery
- Pediatric orthopedics
- Developmental biology
Background:
- Forearm deformities can arise from various conditions affecting ulnar growth.
- Ulnar deficiency, multiple hereditary exostoses, and neurofibromatosis are known causes.
- A novel form of ulnar deformity, focal cortical indentation, is presented.
Observation:
- Five children (3 female, 2 male) presented with this deformity.
- Deformity onset was around age two, with gradual progression.
- Radiological findings consistently showed distal ulnar indentation, anteromedial bowing, dysplasia, and posterolateral radial head dislocation.
Findings:
- Histological examination revealed a periosteum-like tissue fold impeding enchondral ossification at the indentation site.
- Ulnar lengthening via external fixator and osteotomy successfully corrected ulnar deformity.
- Two patients experienced successful reduction of the dislocated radial head following surgical correction.
Implications:
- This study identifies and characterizes a new cause of pediatric forearm deformity.
- Surgical management involving ulnar lengthening and osteotomy offers a viable treatment option.
- Understanding the mechanism of impaired ossification is crucial for future therapeutic strategies.
Abstract:
Deformity of the forearm due to growth disturbance of the ulna occurs in a number of conditions such as ulnar deficiency, multiple exostoses, and neurofibromatosis. We report a previously unrecognised form, caused by focal cortical indentation. We have treated five children with this condition, three girls and two boys; the mean age at presentation was 5 years (2 to 8). The deformity was first recognised about the age of two years, and progressed gradually. The radiological findings were the same in all cases. The focal cortical indentation was seen at the distal end of the ulna with anteromedial bowing and dysplasia. The radial head was dislocated posterolaterally. In one patient the histological findings at the site of indentation were of a fold of tissue resembling periosteum, which interfered with enchondral ossification. Treatment by ulnar lengthening using an external fixator and osteotomy which corrected both the ulnar deformity and reduced the dislocated radial head in two cases gave the best results.
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