Ulnar focal cortical indentation: a progressive, deforming variant of focal fibrocartilaginous dysplasia

Case report: Distraction osteogenesis of focal fibrocartilaginous dysplasia and literature review

INTRODUCTION AND IMPORTANCE

Focal fibrocartilaginous dysplasia (FFCD) is a rare disease of the ulna that requires early surgical intervention.

CASE PRESENTATION

We present a juvenile case and the outcomes of a corrected deformity. The fibrotic band that adhered to the ulna was resected, the ulna was osteotomized, and then an external fixator was placed for lengthening. The ulna's distal physis line was extended by 18 mm so that it would be the same length as the distal physis line of the radius. Full functional recovery occurred within three months.

CLINICAL DISCUSSION

There have been 22 cases of ulnar FFCD reported in the literature. Our patient is the oldest reported thus far who developed radial head subluxation, but no dislocation occurred.

CONCLUSION

FFCD is a broad-spectrum disease. Although its course is generally poor for patients with a late diagnosis, it is possible to obtain good results with correction procedures.

State of the art review: The pathogenesis and management of Madelung deformity

Madelung deformity remains a fascinating yet unresolved challenge. There is an increasing awareness for early diagnosis by healthcare providers with improvement in diagnostic modalities, however, the exact mechanisms for the development of the deformity have still to be clarified. While some corrective procedures have been described to effectively address an established deformity, the existing literature lacks clear and evidence-based treatment guidelines on how to proceed in daily practice. This review article aims to summarize the current best evidence on this topic, including particular areas of controversy and areas with need for future research.

Diagnosis and treatment of focal fibrocartilaginous dysplasia of the distal ulna

Focal fibrocartilaginous dysplasia (FFCD) of the distal ulna is a rare benign lesion resulting in progressive radiocapitellar dislocation, limb deformity and limitation in function. This study reported our experience with 10 cases and it aimed to determine a reasonable strategy for diagnosis and treatment. Ten cases treated from 2010 to 2018 in our department were retrospectively reviewed. The diagnosis was based on imaging features. All patients underwent lesion excision in the early stage and five patients required ulna lengthening in the second stage. The radiographic and functional outcomes were analyzed and reported. The median age at diagnosis was 32 months (range, 6-36 months). The median age at the time of surgery was 34 months (range, 10-40 months). The median clinical and radiographic follow-up period was 37 months (range, 24-50 months). The ulna was shortened by an average of 31 mm (range, 27-35 mm). There was no new radial head dislocation after lesion excision. For five cases of radial head dislocation, the median elbow varus angle before ulnar lengthening was 20° and it decreased to 5° after ulnar lengthening. Supination and pronation of the elbow increased from 50°-10° to 70°-30°. We believe that early excision of the lesion can prevent radiocapitellar joint dislocation in patients with FFCD of the ulna. Ulna lengthening can correct limb deformity and improve the range of motion.

Magnetic resonance imaging of focal fibrocartilaginous dysplasia - findings derived from a three-dimensional gradient echo sequence

BACKGROUND

Focal fibrocartilaginous dysplasia is a rare benign bone lesion of young children that causes deformities in the extremities. However, the pathogenesis and treatments have not been defined and the MR manifestations have been less well described.

OBJECTIVE

To describe the MR manifestations of focal fibrocartilaginous dysplasia, especially on the T1-W three-dimensional (3-D) volumetric interpolated breath-hold examination (VIBE) sequence.

MATERIALS AND METHODS

In this retrospective study, the authors reviewed the MR and radiographic images, pathology and medical records of 21 cases of focal fibrocartilaginous dysplasia. All cases were evaluated by spin-echo MRI sequence. Among them, 17 cases were evaluated by T1-W 3-D VIBE sequence.

RESULTS

The cohort consisted of 13 boys and 8 girls ages 4-75 months. In 14 cases, focal fibrocartilaginous dysplasia was located in the tibia, 3 in the femur and 4 in the ulna. MRI 3-D VIBE sequence findings showed all cases had hypointense fiber band structures in the bone defect areas. The fibrous bands in the lower extremities ended in the epiphysis or epiphyseal plate, and in the upper extremities the epiphysis or carpal bone. Ten cases had hyperintensities that might represent cartilage composition. Four cases had cartilage signals that were continuous with the epiphyseal cartilage. MR spin-echo sequence findings showed that bone marrow edema of the adjacent joint was observed in eight cases, enlargement of the epiphyseal plate in three cases and medial meniscus injury in five cases.

CONCLUSION

The 3-D VIBE sequence reveals useful details in focal fibrocartilaginous dysplasia.