Management of knee deformity in hereditary multiple exostoses: a case report

This article discusses a case of hereditary multiple exostoses suffered by a female patient. The typical clinical and radiographic signs and symptoms are presented. Particular attention is focused on management of a specific knee complaint caused by this condition and the epidemiology of lower limb dysfunction associated with multiple exostoses. Knee deformity in patients with multiple hereditary exostoses presents primarily as genu valgum caused by valgus angulation of the tibia. Changes in ratio of the fibular length to the tibial length are also evident in such patients. The natural history of these deformities is progression with variable weakness, functional impairment, and cosmetic deformity of the extremity. Since malignant degeneration of exostoses to chondrosarcoma is a possibility, management of biomechanical complaints requires continued re-evaluation, rehabilitative techniques and surgical referral if indicated.     

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.     

The association between ulnar length and forearm movement in patients with multiple osteochondromas

PURPOSE: To determine the relationship between the length of the ulna as a proportion of height (proportional ulnar length [PUL]), forearm and wrist ranges of motion, and degree of observable deformity in people with hereditary multiple exostoses. METHODS: One hundred forty-two people with hereditary multiple exostoses were examined; 35 were under the age of 15 years and therefore were presumed to be skeletally immature. Elbow, forearm, and wrist motion were measured, and the radius and ulna were palpated for osteochondromas. Ulnar length was estimated as a proportion of height (PUL) in skeletally immature subjects. The relationships between total active motion, number of palpable osteochondromas, and proportional length were examined for one randomly selected limb from each subject. RESULTS: A negative correlation was found between the number of palpable osteochondromas and range of forearm rotation. The degree of forearm motion in those under the age of 15 years was directly related to PUL and indirectly related to the number of palpable osteochondromas. Children whose PUL is within the normal range have a normal range of motion. CONCLUSIONS: In a child with hereditary multiple exostoses affecting the forearm, the PUL is associated with the range of movement and deformity, and it can be a useful adjunct in deciding the appropriate management.     

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.     

Spontaneous hemothorax in multiple exostoses: a case report and review of literature

Abstract Multiple hereditary exostoses is a rare autosomal dominant disorder characterized by the growth of multiple osteochondromas. We describe the thoracoscopic remodeling of a spiculated costal exostotic lesion responsible for spontaneous recurrent hemothoraces in a 17-year-old male patient with multiple hereditary exostoses.     

What is the Proportion of Patients With Multiple Hereditary Exostoses Who Undergo Malignant Degeneration?

Background

Multiple hereditary exostoses is an autosomal-dominant skeletal disorder that has a wide-ranging reported risk of malignant degeneration to chondrosarcoma.

Questions/purposes

The aims of our study were to use a large, web-based survey approach to characterize (1) the demographic distribution of patients with multiple hereditary exostoses, (2) the number of surgeries performed related to one’s diagnosis of multiple hereditary exostoses, and (3) the proportion of survey respondents who described experiencing malignant degeneration in a large international, heterogeneous cohort of patients with multiple hereditary exostoses.

Methods

An anonymous web-based survey was distributed to several online support groups and social media networks designed to support and educate patients with multiple hereditary exostoses and their families. The survey collected demographic and epidemiologic data on 779 respondents. Data were recorded to assess respondents’ disease burden and the rate of malignant degeneration.

Results

Females represented a slightly greater proportion of those with multiple hereditary exostoses who responded (56% female; 419 of 742 patients). Median age for all respondents was 28 years (range, < 1–85 years). Median age for males was 25 years (range, < 1–85 years), while median age for females was 29 years (range, < 1–82 years). The mean age at diagnosis of male and female respondents was in the mid-first decade (5.4 years ± 7.2 years). The mean number of surgeries a patient had undergone was 7.3 (± 7.1 surgeries). The proportion of respondents who experienced malignant transformation was 2.7% (21 of 757 respondents), at a mean age of 28.6 years (± 9.3 years). The most common sites of malignant change from benign exostoses included the pelvis (eight of 21 respondents) and scapula (four of 21 respondents).

Conclusions

In the largest and most geographically diverse study of patients with multiple hereditary exostoses of which we are aware, we found the proportion of patients with multiple hereditary exostoses who have undergone malignant degeneration to be consistent with those reported in prior studies. Our study perhaps more accurately assessed the proportion of patients who undergo malignant transformation of multiple hereditary exostoses. As with prior studies on this topic, the proportion of malignant change may be expected to represent a high-end estimate as recruitment and selection bias likely predisposes for patients with more severe disease, whereas patients with lesser disease may be unaware of their diagnosis. In discussing the sequelae of multiple hereditary exostoses, clinicians perhaps might use this study to offer an unspecific statement of risk of malignant degeneration of multiple hereditary exostoses among the population at large.

Level of Evidence

Level IV, prognostic study.     

Selective Computed Tomography-guided Perisciatic Injection as a Diagnostic Tool in Multiple Hereditary Exostoses

Multiple osteochondromas, also known as multiple hereditary exostoses, is an autosomal-dominant disease. Multiple osteochondromas are characterized by the development of cartilage-capped bony tumors, known as osteochondromas. Osteochondromas can cause limb deformities, limb-length discrepancies, angular deformations, bursitis, and impingement of adjacent tendons or neurovascular structures. They have also been reported as a cause of sciatic pain. Sometimes, more than 1 location of neural compression exists, thereby presenting a difficult diagnostic challenge for treating physicians.This article describes a patient with multiple hereditary exostoses and accompanying severe sciatic pain who was referred for a revision decompressive spine surgery. The patient's functional impairment was such that he was unable to sit for a few minutes. A selective computed tomography-guided perisciatic nerve injection was performed to differentiate between lateral spinal stenosis and peripheral nerve compression or impingement by an existing large pelvic osteochondroma. The patient reported substantial relief and regained the ability to sit pain free immediately postoperatively. Excision of a proximal femur osteochondroma was performed based on the results of a selective perisciatic nerve injection, resulting in successful resolution of his sciatic pain and functional impairment.The current case is an example of the diagnostic challenge in treating patients with multiple anatomic lesions that can cause symptoms and demonstrate how selective computed tomography-guided perisciatic nerve injection can aid clinicians in obtaining an accurate diagnosis and choosing the most appropriate surgical management.     

Tibial osteochondroma causing foot pain mimicking tarsal tunnel syndrome: A case report

Nerve entrapment syndromes of the lower extremity are relatively rare in patients with multiple hereditary osteochondromatosis. A case of tarsal tunnel like symptoms in a 52-year-old woman with a distal tibial osteochondroma is presented. This case emphasizes that the possibility of nerve compression needs to be considered in a patient with multiple hereditary osteochondromatosis and that tibial osteochondromas can be a cause of tarsal tunnel-like symptoms.     

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.     

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.     

Manifestations of hereditary multiple exostoses

The solitary osteochondroma, a common pediatric bone tumor, is a cartilage-capped exostosis. Hereditary multiple exostosis is an autosomal dominant disorder manifested by the presence of multiple osteochondromas. Linkage analysis has implicated mutations in the EXT gene family, resulting in an error in the regulation of normal chondrocyte proliferation and maturation that leads to abnormal bone growth. Although exostoses are benign lesions, they are often associated with characteristic progressive skeletal deformities and may cause clinical symptoms. The most common deformities include short stature, limb-length discrepancies, valgus deformities of the knee and ankle, asymmetry of the pectoral and pelvic girdles, bowing of the radius with ulnar deviation of the wrist, and subluxation of the radiocapitellar joint. For certain deformities, surgery can prevent progression and provide correction. Patients with hereditary multiple exostosis have a slight risk of sarcomatous transformation of the cartilaginous portion of the exostosis.     

Metachondromatosis: more than just multiple osteochondromas

Introduction

Metachondromatosis is a rare genetic disease of osteochondroma and enchondroma formation, caused by loss of function of the PTPN11 gene. It is distinct from other similar conditions such as multiple osteochondromas and hereditary multiple exostoses by the distribution and orientation of lesions, and pattern of inheritance. Lesions typically occur in hands, feet, femora, tibiae and the pelvis. Lesions are typically reported to regress in adulthood.

Methods

We reviewed the current literature on metachondromatosis, and present four new cases in a family with metachondromatosis.

Results

Long-term follow up data reveal spontaneous regression of lesions by skeletal maturity. Complications may include nerve palsy due to the mass effect of lesions, avascular necrosis of the femoral head and angular deformity of long bones. Histopathological analysis has demonstrated that lesions in metachondromatosis are a mix of osteochondromas and enchondromas; however, one case of chondrosarcoma has been reported.

Conclusion

Lesions associated with metachondromatosis may cause a variety of complications due to mass effects; however, they are often asymptomatic, cause cosmetic concerns and, importantly, most regress spontaneously. Regular clinical review with selective imaging to monitor for such complications is appropriate, but uncomplicated lesions are unlikely to require surgical intervention.     

Correction and lengthening for deformities of the forearm in multiple cartilaginous exostoses

Background Multiple cartilaginous exostoses cause various deformities of the epiphysis. In exostoses of the ulna, the ulna is shortened and the radius acquires varus deformity, which may lead to dislocation of the radial head. In this study, we present the results of exostoses resection, with correction and lengthening with external fixators for functional and cosmetic improvement, and prevention of radial head dislocation. Methods We retrospectively reviewed seven forearms of seven patients who had deformities of the forearm associated with multiple cartilaginous exostoses. One patient had dislocation of the radial head. Operative technique was excision of osteochondromas from the distal ulna, correction of the radius, and ulnar lengthening with external fixation up to 5 mm plus variance. We evaluated radiographs and the range of pronation and supination. Furthermore, we conducted a follow-up of ulnar length after the operation. Results Dislocation of the radial head of one patient was naturally reduced without any operative intervention. At the most recent follow-up, six of the seven patients showed full improvement in pronation–supination. Ulnar shortening recurred with skeletal growth of four skeletally immature patients; however, it did not recur in one skeletally mature patient. Overlength of 5 mm was negated by the recurrence of ulnar shortening about 1.5 years after the operation. Conclusions We treated seven forearms of seven patients by excision of osteochondromas, correction of radii, and gradual lengthening of ulnas with external fixators. The results of the procedure were satisfactory, especially for function of the elbow and wrist. However, we must consider the possible recurrence of ulnar shortening within about 1.5 years during skeletal growth periods in immature patients.     

Spinal cord compression secondary to a thoracic vertebral osteochondroma

The authors describe a case of spinal cord compression due to an osteochondroma arising from the T-6 vertebral body in a patient with hereditary multiple exostoses. This 16-year-old boy presented with spastic paraparesis. Surgical decompression was followed by resolution of the neurological impairments. Osteochondroma is the most common bone tumor. The distribution of osteochondromas greatly favors the extremities and these lesions rarely arise in the vertebral column. Osteochondromas occur in 2 distinct clinical settings--as solitary or multiple tumors, the latter being often associated with hereditary multiple exostoses. Osteochondromas are more commonly found in the posterior elements of the vertebrae. Intraspinal presentation of these tumors is usually limited to the cervical regions, with few tumors reported in the thoracic vertebrae. Based on the presented case and literature review, the authors conclude that osteochondromas of the thoracic spine that cause myelopathy usually arise from the vertebral body and pedicle. Prompt and systematic radiological investigations are important in planning surgical management. Surgical excision usually yields good results.     

Spinal cord compression due to vertebral osteochondroma: report of two cases

Osteochondroma, or exostosis, is the most common of all benign bone tumors. Spinal osteochondromas are uncommon but may cause neurological compromise. We report two cases of spinal cord compression by osteochondromas. One patient was a 17-year-old man with hereditary multiple exostoses who was presented with spastic paraparesis, a sensory level at T3-T4, and a pyramidal syndrome. Vertebral exostosis was suspected by magnetic resonance imaging and confirmed by histological examination. Surgical decompression was followed by complete resolution of the neurological impairments. The other patient was a 19-year-old man with spastic paralysis of the right lower limb and a pyramidal syndrome. Whereas magnetic resonance imaging suggested a neurofibroma, histological features were those of osteochondroma. Nine months elapsed from symptom onset to surgery. This delay led to residual neurological impairments, which resolved almost completely after rehabilitation therapy. Vertebral osteochondromas contribute only 1.3-4.1% of all osteochondromas. The lesion may be solitary or a manifestation of hereditary multiple exostosis. Magnetic resonance imaging shows the exact location of the lesion, most notably with relation to neighboring neurological structures. Spinal cord compression is uncommon and usually has a favorable outcome provided surgical decompression is performed before major neurological damage develops.     

Hand involvement in multiple hereditary exostosis

In summary, patients with multiple hereditary exostosis often inherit hand involvement but rarely show hand deformity. The principal area of involvement appears to be around the MCP joint but the PIP joint is the most common area of deformity. Metacarpal shortening usually does not cause functional problems and need not be treated. Angular deformity, though rare, does cause problems and needs surgical treatment. Unfortunately, there is no evidence that prevention of deformity is possible by early excision of osteochondromas. Treatment, therefore, requires both osteochondroma excision and closing-wedge corrective osteotomy.     

Multiple hereditäre Exostosen am Schultergürtel

Osteochondromas develop due to an improper regulation of chondrocyte differentiation. About 15?% of the patients show multilocular tumor appearance. Multiple hereditary exostoses (MHE) as an autosomal dominant disorder characterized by multiple osteochondromas have an incidence rate of 2:100,000. Tumor manifestation at the side of the clavicle and at the processus coracoideus is rarely described. We report a case of symptomatic MHE of the shoulder girdle as a rare reason for an extrinsic mechanical irritation of the rotator cuff compromising the axillary vessel-nerve cord.     

Severity of disease and risk of malignant change in hereditary multiple exostoses. A genotype-phenotype study

We performed a prospective genotype-phenotype study using molecular screening and clinical assessment to compare the severity of disease and the risk of sarcoma in 172 individuals (78 families) with hereditary multiple exostoses. We calculated the severity of disease including stature, number of exostoses, number of surgical procedures that were necessary, deformity and functional parameters and used molecular techniques to identify the genetic mutations in affected individuals. Each arm of the genotype-phenotype study was blind to the outcome of the other. Mutations EXT1 and EXT2 were almost equally common, and were identified in 83% of individuals. Non-parametric statistical tests were used. There was a wide variation in the severity of disease. Children under ten years of age had fewer exostoses, consistent with the known age-related penetrance of this condition. The severity of the disease did not differ significantly with gender and was very variable within any given family. The sites of mutation affected the severity of disease with patients with EXT1 mutations having a significantly worse condition than those with EXT2 mutations in three of five parameters of severity (stature, deformity and functional parameters). A single sarcoma developed in an EXT2 mutation carrier, compared with seven in EXT1 mutation carriers. There was no evidence that sarcomas arose more commonly in families in whom the disease was more severe. The sarcoma risk in EXT1 carriers is similar to the risk of breast cancer in an older population subjected to breast-screening, suggesting that a role for regular screening in patients with hereditary multiple exostoses is justifiable.     

Acetabular dysplasia associated with hereditary multiple exostoses. A case report

Hereditary multiple exostoses is an autosomal dominant disorder characterised by multiple osteochondromata, most commonly affecting the forearm, knee and ankle. Osteochondromata of the proximal femur have been reported to occur in 30% to 90% of affected patients with coxa valga in 25%. Acetabular dysplasia is rare but has been described. This is the first report of a patient requiring surgical intervention. A girl was seen at the age of nine with hereditary multiple exostoses and when 12 developed bilateral pain in the groin. Radiographs showed severely dysplastic acetabula with less than 50% coverage of the femoral heads and widening of the medial joint space. Large sessile osteochondromata were present along the medial side of the femoral neck proximal to the lesser trochanter, with associated coxa valga. The case illustrates the importance of obtaining initial skeletal surveys in children with hereditary multiple exostoses to identify potential problems such as acetabular dysplasia and subluxation of the hip.