The hip in hereditary multiple exostoses

We defined the characteristics of dysplasia and coxa valga in hereditary multiple exostoses (HME) by radiological analysis of 24 hips in 12 patients. The degree and effect of the 'osteochondroma load' around the hip were quantified. We investigated the pathology of the labrum and the incidence of osteoarthritis and of malignant change in these patients. Coxa valga and dysplasia were common with a median neck-shaft angle of 156 degrees, a median centre-edge angle of 23 degrees and Sharp's acetabular angle of 44 degrees. There was overgrowth of the femoral neck with a significantly greater ratio of the neck/shaft diameter in HME than in the control hips (p < 0.05), as well as correlations between the proximal femoral and pelvic osteochondroma load (p < 0.05) and between the proximal femoral osteochondroma load and coxa valga (p < 0.01). Periacetabular osteochondromas are related to Sharp's angle as an index of dysplasia (p < 0.05), but not coxa valga. No correlation was found between dysplasia and coxa valga. These data suggest that HME may cause anomalies of the hip as a reflection of a generalised inherited defect, but also support the theory that osteochondromas may themselves precipitate some of the characteristic features of HME around the hip.     

Cervical myelopathy in hereditary multiple exostoses

Spinal cord compression due to cervical exostoses is a rare but recognized complication of hereditary multiple exostosis (HME), an autosomal dominant disorder. This disease, also called multiple osteochondromatosis, is characterised by osteocartilaginous exostoses, typically involving the juxtaepiphyseal regions of long bones. Complications such as transformation to sarcoma (1 to 5%) or neurological compression (of the spinal cord, 1 to 9%) can arise during the course of the disease. We report the case of a 64-year-old man with progressive difficulties in walking over many years, ascribed to congenital rachitism. A diagnosis of HME was not made until late in the disease course. Investigations revealed cervical myelopathy due to vertebral exostosis as well as multiple exostoses in other sites. His gait was not improved after surgical decompression. A better knowledge of this disease could have prevented this neurological complication.     

Subacromial impingement syndrome in hereditary multiple exostoses

An unusual cause of subacromial pain was observed in a 32-year-old woman with multiple exostoses. The pain was the direct result of the mechanical impingement syndrome from these exostoses. Hereditary multiple exostoses should be investigated systematically, because many other, more common pain-producing conditions are possible. Secondary malignant degeneration of one of the cartilaginous coverings of the exostoses is very rare.     

Popliteal artery pseudo-aneurysm and hereditary multiple exostoses

We describe a rare case of a 21-year-old man presenting with hereditary multiple exostosis and a pseudoaneurysm of the popliteal artery caused by femoral osteochondroma. Principles of management and surgical technique are discussed.     

Cervical spinal cord compression in hereditary multiple exostoses

Spinal cord compression is an extremely serious complication of hereditary multiple exostoses (HME). A case of HME with compression of the cervical spinal cord is reported. Complete recovery following surgery was achieved. A review of the relevant literature revealed 51 previous cases of HME with cord/cauda equina compression. Most patients were under 30 years of age with more men affected than women. The family history was positive in 60%. The cervical and thoracic areas were predominantly affected, with the symptoms usually developing slowly. Recovery following surgery is to be expected in the majority of cases. In patients with HME and suffering from neurological symptoms, the possibility of spinal cord compression should be considered. Prompt diagnosis and surgical excision provide the best prognosis.     

Acute spinal cord compression in hereditary multiple exostoses

Summary Osteocartilaginous exostoses are benign bone tumors frequently found in the metaphysis of long bones but rarely in the spine. Four patients with acute spinal cord decompensation due to vertebral exostoses spinal cord compression have been previously described in the literature. We report an additional case of rapidly evolving spinal cord compression due to a cervical osteochondroma in a patient with hereditary multiple exostoses (HME), also known as Bessel Hagen disease. Careful analysis of the 5 cases suggested to us that patients with HME should have a systematic spinal imaging screening, in order to prevent rapid neurological decompensation. A minimal risk surgical procedure can be performed at a time of election.     

Chondrosarcoma in a family with multiple hereditary exostoses

Multiple hereditary exostoses is an autosomal dominant skeletal disorder in which there are numerous cartilage-capped excrescences in areas of actively growing bone. The condition is genetically heterogeneous, and at least three genes, ext1, ext2 and ext3 are involved. The reported risk for malignant transformation to chondrosarcoma has been from 0.6% to 2.8%. We have reviewed six generations of a family with 114 living adult members, 46 of them with multiple exostoses. Four have had operations for chondrosarcoma, giving the risk for malignant transformation as 8.3% in this family. Clinical and radiological examination revealed two additional patients with a suspicion of malignancy, but in whom the histological findings were benign. Reported elsewhere in detail, genetic linkage analysis mapped the causative gene to chromosome 11 and molecular studies revealed a guanine-to-thymine transversion in the ext2 gene. Patients with multiple hereditary exostoses carry a relatively high risk of malignant transformation. They should be informed of this possibility and regularly reviewed.     

Spinal stenosis frequent in children with multiple hereditary exostoses

Purpose

Children with multiple hereditary exostoses (MHE) have numerous osteochondromas, with the most prominent lesions typically over the appendicular skeleton. A recent report noted a high rate of intracanal lesions in this patient population and recommended preventative spinal screening with magnetic resonance imaging (MRI) or computed tomography (CT). We sought to evaluate the prevalence of spinal stenosis from intracanal osteochondromas at our pediatric orthopedic center in order to evaluate if routine screening is warranted.

Methods

All pediatric patients treated for MHE were retrospectively identified. Records were reviewed to determine demographics, previous orthopedic surgery, and indication and results of axial spine imaging (CT or MRI). Imaging studies were reviewed to evaluate the presence of intracanal and compressive spinal lesions.

Results

Between 1990 and 2011, axial imaging was performed in nine patients with MHE due to concerns of pain, weakness, and/or dizziness. These patients had moderate disease involvement, with a mean of 4.9 previous orthopedic surgeries to address skeletal osteochondromas. Two patients with MHE had cervical spinal stenosis secondary to intracanal osteochondromas. Both children successfully underwent spinal decompression. Thus, of our MHE population undergoing axial imaging, 22 % were noted to have intracanal lesions.

Conclusions

Our experience reveals a >20 % rate of compressive intracanal osteochondromas in MHE patients undergoing spinal imaging. These two patients represent 5 % of the MHE patients treated at our center. These lesions may be slow growing, and significant consequences can occur if not identified promptly. Thus, we confer that routine axial screening of the spinal canal may be warranted in these children.     

Hemiepiphyseal stapling for ankle valgus in multiple hereditary exostoses

If left uncorrected, valgus ankle deformity in multiple hereditary exostoses can cause significant disability in skeletally immature children and in adults. Various management methods have been described, including hemiepiphyseal stapling, transphyseal screw placement, fibular-Achilles tenodesis, distal tibial osteotomy, and ablative epiphyseodesis. In this article, we report the cases of 3 skeletally immature children who had undergone hemiepiphyseal stapling of the medial distal tibial epiphysis for correction of valgus ankle deformity in multiple hereditary exostoses. Correction of the tibiotalar axis, in relation to chronological and bone age, was evaluated. Hemiepiphyseal stapling of the medial distal tibial epiphysis provides ipsilateral corrective potential while allowing staple removal for reversal of growth retardation. This procedure is useful in the management of ankle valgus in multiple hereditary exostoses.     

Spontaneous hemothorax in a patient with hereditary multiple exostoses

A case of spontaneous hemothorax in a 7-year-old child secondary to erosion of the diaphragm by an exostosis coming from the left sixth rib is reported. This rare case of hemothorax with hereditary multiple exostoses is made even rarer by the concomitant perforation of the diaphragm.     

Lengthening the ulna in patients with hereditary multiple exostoses

Deformity of the forearm is common in patients with hereditary multiple exostoses, producing cosmetic and functional impairment in which shortening of the ulna is a significant factor. The results of ulnar lengthening in 10 forearms of eight patients are reported. Lengthening was performed by osteotomy of the shaft followed immediately by a bone graft and internal fixation, or by gradual distraction with an external fixator. In all patients the appearance was improved and the range of radial deviation at the wrist was increased. In most patients forearm movement and radial head stability were improved. Partial recurrence of the deformity was seen during the follow-up of skeletally immature patients, but in general ulnar lengthening was found to be a useful operation.     

Acute cervical myelopathy from hereditary multiple exostoses: case report

A case of hereditary multiple exostoses with acute cervical myelopathy, tetraplegia, and apnea is reported. Neurological complications as a result of osteochondromas in hereditary multiple exostoses are rare. The majority of osteochondromas in the cervical spine arise from the neural arch. Magnetic resonance imaging and computed tomography are invaluable in localizing the origin of the lesion and its relationship to the spinal cord. Decompressive laminectomy usually results in excellent functional recovery. Where significant dorsal spinal cord compression exists without neurological deficit, prophylactic decompression can be recommended.     

Clinical outcome and genotype in patients with hereditary multiple exostoses

Hereditary multiple exostoses (HME) is an autosomal dominant skeletal disorder with a wide spectrum of clinical manifestations. In 52 out of 60 individuals from HME+ families, exostoses became clinically apparent. In this study, the clinical and radiological outcome of these 52 HME patients (19 families) was investigated by medical history, clinical examination, and radiographs. In addition to correlating phenotype with genotype, a linkage/exclusion analysis was performed in 35 HME patients. We found several correlations between HME genes (EXT1, EXT2) and phenotype. Compared to EXT2‐linkage, female individuals with EXT1‐linkage were smaller in stature. Patients with EXT1‐linkage and patients with undetermined linkage (EXT?) were more severely affected, underwent more surgeries, and showed a higher number of exostoses at follow‐up. Moreover, we found an increased phenotype risk for limb shortening for EXT1‐ and EXT?‐linkage. This study corresponds to data of other investigators who showed that EXT1 mutations are associated with a more severe phenotype than other EXT forms. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1541–1551, 2007