Developmental pattern of the hip in patients with hereditary multiple exostoses

A Healed Intertrochanteric Femur Fracture, Shoulder, and Rib Fractures in an Ancient Nubian Female: An Osteoarchaeological Perspective

This report is a case of a healed proximal intertrochanteric femur fracture nonunion in an ancient Nubian adult female, approximately 58 years old at the time of death, from the Tombos archaeological site in present day northern Sudan. Tombos was founded as an Egyptian colonial town during the New Kingdom Period (14001070 BC). The individual was radiocarbon dated to 1114-910 BC and also exhibited healed fractures of the left proximal humerus and ribs. There was shortening and mild atrophy of the right femur compared to the left; radiographs demonstrated a varus deformity of the proximal femur with associated retroversion. Bone density analysis revealed that the tissue mineral density z-score for this individual was -0.798, with the z-score for Tombos females 15-24 years old being 0.396, or a total difference of 1.194. This indicates that the individual was osteopenic but not osteoporotic prior to demise. This is an important case as it occurred approximately 3000 years ago and is the oldest known reported case of a healed intertrochanteric hip fracture in the archaeological literature. Archaeological cases of intertrochanteric hip fractures are rare, with none previously reported from the BC era. The timing of these multiple fractures is unknown, but all healed before the demise of the individual. Thus, there must have been considerable care afforded to such an individual to minimize the morbidities associated with nonoperative care of such a fracture. If all these fractures occurred at the same time due to a traumatic, accidental injury, the Modified Injury Severity Score (MISS) would be 25. Modern day trauma resuscitation and orthopaedic care gives an estimated mortality for such a MISS score of 28% for those <50 years old. It is likely that this individual's high socioeconomic status allowed for intensive nursing care which likely decreased the morality risk.

Guided Growth Improves Coxa Valga and Hip Subluxation in Children With Hereditary Multiple Exostoses

BACKGROUND

In children with severe hereditary multiple exostoses (HME), coxa valga, and hip subluxation are common deformities. The literatures related to surgical management and prevention of hip joint subluxation in HME are scarce. In this study, we aimed to investigate the efficacy of guided growth procedure to correct coxa valga and hip subluxation in HME patients.

METHODS

We retrospectively retrieved 12 patients who received guided growth procedures for coxa valga and hip subluxation in HME patients with proximal femur exostoses with a minimum follow-up time of 2 years between 2012 and 2019. Radiographic parameters include head-shaft angle, Hilgenreiner-epiphyseal angle, acetabular index, Reimer migration percentage, center-edged angle, articulo-trochanteric distance, and femoral neck length for comparison between preoperative and latest follow-up results. It was conducted statistically by paired t test and Wilcoxon signed rank test.

RESULTS

In this study, the mean difference between preoperative and latest follow-up was significant in head-shaft angle (12±5 degrees; CI, 10-14; P<0.001), Hilgenreiner-epiphyseal angle (12±5 degrees; CI, 10-15; P<0.001), and MP (7%±8%; CI, 3-11; P=0.001). There was a low revision rate (4 of 21, 19%) and no complication in our study. Compared with previous studies on guided growth in children with cerebral palsy and developmental dysplasia of the hip, our study showed good comparable outcomes.

CONCLUSION

The results indicated that guided growth improves the hip radiographic parameters of children with HME and may prevent coxa valga and hip subluxations. It is a safe procedure and provides predictable results.

LEVEL OF EVIDENCE

Level IV; therapeutic, case series.

A Case Report of Trevor's Disease in a Pediatric Patient with Hereditary Multiple Exostoses Disease

Introduction

Hereditary multiple exostoses (HME) disease is hallmarked by cartilaginous osteochondromas secondary to an autosomal dominant mutation within the exostosin gene family. These outgrowths predominantly occur around the long bone physis. An associated disease is dysplasia epiphysealis hemimelica also known as Trevor's disease. Trevor's disease is hallmarked by intra-articular osteochondromas. While the two diseases are similar, they are not genetically related and often have differing patient presentations.

Case Report

We report on a case of a 7-year-old female with a familial history significant for HME that presented with an isolated chief complaint of elbow extension block secondary to osteochondromas found both intra-articular and at the olecranon fossa. We present what could be one of the first cases of coexisting HME and Trevor's disease of the upper extremity.

Conclusion

Our patient's unique presentation of an intra-articular osteochondroma speculated to be a result of Trevor's disease, in the presence of an established HME diagnosis. Management for this patient did not deviate heavily from the established approach for HME which entails conservative observation until symptomatic. Due to the substantial loss of range of motion (ROM), surgical intervention took place in the form of exostoses removal and necessary reconstruction of the fossa. The patient's ROM subsequently was restored to near normal.

An update on the imaging of diaphyseal aclasis

Solitary osteochondromas are common, benign hyaline cartilage-capped exostoses that primarily arise from the metaphyses of long and flat bones. Diaphyseal aclasis is an autosomal dominant condition resulting from EXT1 or EXT2 gene mutations and is characterized by multifocal osteochondromas. These can result in a wide spectrum of complications, such as skeletal deformity, neurological and vascular complications, adventitial bursa formation, fracture, and rarely malignant transformation to peripheral chondrosarcoma. In this review, we outline in detail the multimodality imaging features of DA and its associated complications.

Osteochondromas: An Updated Review of Epidemiology, Pathogenesis, Clinical Presentation, Radiological Features and Treatment Options

Osteochondroma, the most common benign bone tumor, is a projection on the external surface of the bone, which can be sessile or pedunculated. 85% of osteochondromas present as solitary lesions, while 15% occur in the context of hereditary multiple exostoses (HME), a genetic disorder that is inherited in an autosomal dominant manner. Although often asymptomatic, symptoms may eventuate from compression of adjacent vessels or nerves, fractures, osseous deformities, bursa formation, or malignant transformation. Cartilage cap thickness >2 cm in adults or >3 cm in children as well as new onset of pain or growth, or rapid growth of the lesion, especially after the closure of the growth plate, might reflect cancerous transformation. Surgical resection is indicated for symptomatic lesions, complications, cosmetic reasons or malignant transformation. Excision of the tumor with free margin is the treatment of choice. Local recurrence is less than 2% if complete resection is achieved.

Total Hip Arthroplasty for Secondary Coxarthrosis in Patients with Hereditary Multiple Exostoses: Minimum 5-Year Follow-up Results and Surgical Considerations

Background

Hereditary multiple exostoses (HME) is an autosomal dominant disorder. The lesion in the proximal femoral metaphysis can bring about hip dysplasia and subsequent degenerative arthritis. Due to its rare prevalence, there have been a few case reports of total hip arthroplasty (THA) for osteoarthritis secondary to HME. The aim of this study was to report mid- to long-term outcomes of THA in HME patients and discuss special considerations that should be taken into account during surgery.

Methods

We retrospectively evaluated the clinical and radiological results of THA for osteoarthritis secondary to HME in 11 hips of 9 patients after a minimum follow-up of 5 years (mean, 9.9 years). There were 3 men (3 hips) and 6 women (8 hips), with a mean age of 53.6 years (range, 46.8–58 years) at the index surgery in this study. Harris hip score (HHS) was used for clinical outcome assessment, and radiologically, implant stability, radiolucent lines, liner wear, and any sign of osteolysis or implant loosening were evaluated. Postoperative complications including infection, deep vein thrombosis, and dislocations were also investigated.

Results

Cemented stems and cementless cups with the conventional polyethylene liner were used in bilateral hips of a single patient. In the other cases, cementless implants were used with ceramic-on-ceramic bearings. The mean HHS improved from 34.8 preoperatively to 92.5 postoperatively. Polyethylene liner wear and osteolysis were observed in 1 patient with cemented stems. Radiolucent lines were observed in 2 different cases. However, the femoral stems remained stable. There were no surgery-related complications except heterotopic ossification during follow-up.

Conclusions

Despite the several surgical considerations, the mid- to long-term clinical and radiological outcomes of THA in HME patients were satisfactory. The abnormal, wide mediolateral diameter of the proximal metaphysis should be considered in selecting and inserting the stem with adequate anteversion. Leg length discrepancy was also common, so teleradiographs should be obtained before surgery. Intraoperative leg length evaluation might be difficult due to the morphologic changes in the proximal femur after mass excision and individual bone length differences.

Radiographic characteristics of the hip joint in skeletally mature patients with multiple hereditary exostoses

OBJECTIVE

To elucidate the radiological characteristics of the hips, especially in proximal femur, of skeletally mature patients with multiple hereditary exostoses (MHE).

MATERIALS AND METHODS

Fifty eligible patients (100 hips) were included in the study and assigned to the MHE group. The control group included age- and sex-matched individuals, and the radiographs of 100 hips were used as controls. We examined the anatomical characteristics of the acetabulum and the proximal femur, including the acetabular depth-width ratio (ADR), Sharp's angle, femoral neck-shaft angle (NSA), Wiberg's centre-edge angle (CEA), femoral neck axis length (FNAL), femoral head diameter, (FHD), femoral neck width (FNW), femoral shaft width (FSW), femoral neck-shaft angle (NSA), and femoral head-neck ratio (FHNR = FHD/FNW). p value < 0.05 was considered significant.

RESULTS

Osteochondroma was frequently observed in the medial femoral neck (79%), but it was rarely found in the femoral head (1%). ADR and Sharp's angle were not significantly different between the MHE and control groups (p = 0.2056, p = 0.5025). CEA was significantly different between the two groups (p < 0.0001). FNW was significantly larger in the MHE group than in the control group (p < 0.0001). FHNR was significantly different between the two groups (p < 0.0001). NSA was significantly larger than the MHE group (141.8° ± 9.7° vs 129.5° ± 5.6°, p < 0.0001).

CONCLUSIONS

Hip dysplasia in the pelvic side was not commonly observed in skeletally mature MHE patients. However, they showed femoral neck widening and coxa valga. The occurrence of osteochondroma around the femoral neck affects the degree of valgus deformity. These facts could be useful for orthopaedic surgeons treating MHE patients.

Hereditary Multiple Exostoses: Current Insights

Hereditary multiple exostoses (HME), also called hereditary multiple osteochondromas, is a rare genetic disorder characterized by multiple osteochondromas that grow near the growth plates of bones such as the ribs, pelvis, vertebrae and especially long bones. The disease presents with various clinical manifestations including chronic pain syndromes, restricted range of motion, limb deformity, short stature, scoliosis and neurovascular alteration. Malignant transformation of exostosis is rarely seen. The disease has no medical treatment and surgery is only recommended in symptomatic exostoses or in cases where a malignant transformation is suspected. HME is mainly caused by mutations and functional loss of the EXT1 and EXT2 genes which encode glycosyltransferases, an enzyme family involved in heparan sulfate (HS) synthesis. However, the peculiar molecular mechanism that leads to the structural changes of the cartilage and to osteochondroma formation is still being studied. Basic science studies have recently shown new insights about altering the molecular and cellular mechanism caused by HS deficiency. Pediatricians, geneticists and orthopedic surgeons play an important role in the study and treatment of this severe pathology. Despite the recent significant advances, we still need novel insights to better specify the role of HS in signal transduction. The purpose of this review was to analyze the most relevant aspects of HME from the literature review, give readers an important tool to understand its clinical features and metabolic-pathogenetic mechanism, and to identify an effective treatment method. We focused on the aspects of the disease related to clinical management and surgical treatment in order to give up-to-date information that could be useful for following best clinical practice.

Radiographic Analysis of the Pediatric Hip Patients With Hereditary Multiple Exostoses (HME)

BACKGROUND

This study aimed to report the radiographic presentation of involved hips in children with hereditary multiple exostoses (HME). This included radiographic hip measurements, osteochondromas location, and relationship with hip subluxation.

METHODS

Anteroposterior pelvis radiographs of children with HME, seen between 2003 and 2014, were retrospectively reviewed. Only patients who were skeletally immature at the first visit were included. One radiograph per patient per year was reviewed. Radiographs were examined for the presence of osteochondromas and their locations. Different parameters were evaluated: femoral neck-shaft angle, Reimer migration percentage (MP), Sharp acetabular angle, Wiberg angle, femoral head-neck ratio (coronal plane), and Shenton line. All measured radiographs were divided into 3 age groups:≤8,>8 and <13, and ≥13 years. Differences of the measured parameters with age were evaluated. Children with hip subluxation were identified and any relationship with osteochondromas locations, as well as MP changes over time, was recorded. Radiographs of children with a minimum 2-year follow-up were identified and changes of their hip measurements and osteochondromas' presence over time were recorded.

RESULTS

A total of 51 children (102 hips) with HME were identified. In most locations, there was an overall increase of the occurrence of osteochondromas in the older age groups. However, in the medial femoral neck, a significantly less numbers of osteochondromas were found after 13 years of age (P=0.018). There was a decrease in MP with age (P<0.05). There was also an increase in Sharp and Wiberg angles in the older patients (P<0.05). Hips with broken Shenton line decreased in number with age (P 0.028). Hip subluxation was encountered in 23 hips. No specific location of osteochondromas was found to have a relationship with subluxation. Thirty-six children had a minimum follow-up of 2 years (mean age at first visit 8.5 y and at last visit 13.1 y). In these children, an increased occurrence of lesions was found in medial femoral neck and ischium (P<0.05) between the first and the last visit.

CONCLUSIONS

In children with HME, radiographic evaluation of the hip is necessary based on the high percentage of hip involvement. When hip osteochondromas are found, radiographic surveillance is recommended to detect hip subluxation. Surgery may certainly be necessary for symptomatic osteochondromas. However, given the possibility of improvement in hip parameters with age, early surgical treatment to improve hip longevity does not seem to be warranted.

LEVEL OF EVIDENCE

Level IV-prognostic study.

Magnetic Resonance Imaging in Symptomatic Children With Hereditary Multiple Exostoses of the Hip

BACKGROUND

Magnetic resonance imaging (MRI) is useful in evaluating nontraumatic hip pain. It provides information about associated injuries like labral/chondral tears or ischiofemoral impingement (IFI). However, in hereditary multiple exostoses (HME) there has been no report about MRI findings in symptomatic children with hip involvement.

METHODS

Records of children with HME and hip osteochondromas, who had hip MRI/magnetic resonance arthrography, were reviewed. The presence of chondral lesions and labral tears, as well the presence of IFI, was recorded. IFI was defined as edema or fatty replacement/atrophy in the quadratus femoris muscle or decrease of the space for this muscle between the ischium and the proximal femur. The measurements used to determine the space included the ischiofemoral space, the quadratus femoris space, and the minimum ischiofemoral space (MIFS). All measurements were performed on axial T1-weighted images.

RESULTS

Ten children were included (4 males, 6 females). In 2 patients, MRI was unilateral, therefore a total of 18 hips were analyzed. The indication for MRI was hip pain. Mean age, when MRI was performed, was 11.7 years. Labral tears were found in 44% (8/18) and chondral lesions in 33% (6/18) of the hips. The mean ischiofemoral space was 17.2 mm (SD, 7.3), the mean quadratus femoris space was 14.9 mm (SD, 5.3), and the mean MIFS was of 12.8 mm (SD, 5.9). IFI was seen in 44% (8/18) of hips. Two patients had bilateral IFI. MIFS was <10 mm in all hips with IFI (8/8). Of these hips, 88% (7/8) had edema of the quadratus femoris muscle and 38% (3/8) had fatty replacement/atrophy in the muscle. Osteochondromas were seen in the lesser trochanter in all hips with IFI (8/8) and in the ischium in 50% of them (4/8).

CONCLUSIONS

In symptomatic children with HME of the hip, MRI is helpful in detecting the source of pain. A high percentage of these children have IFI and intra-articular lesions. These findings can play an important role in the indication and planning of the surgical approach.

LEVEL OF EVIDENCE

Level IV-diagnostic study.

Hereditary Multiple Exostoses: New Insights into Pathogenesis, Clinical Complications, and Potential Treatments

PURPOSE OF REVIEW

Hereditary multiple exostoses (HME) is a complex musculoskeletal pediatric disorder characterized by osteochondromas that form next to the growth plates of many skeletal elements, including long bones, ribs, and vertebrae. Due to its intricacies and unresolved issues, HME continues to pose major challenges to both clinicians and biomedical researchers. The purpose of this review is to describe and analyze recent advances in this field and point to possible targets and strategies for future biologically based therapeutic intervention.

RECENT FINDINGS

Most HME cases are linked to loss-of-function mutations in EXT1 or EXT2 that encode glycosyltransferases responsible for heparan sulfate (HS) synthesis, leading to HS deficiency. Recent genomic inquiries have extended those findings but have yet to provide a definitive genotype-phenotype correlation. Clinical studies emphasize that in addition to the well-known skeletal problems caused by osteochondromas, HME patients can experience, and suffer from, other symptoms and health complications such as chronic pain and nerve impingement. Laboratory work has produced novel insights into alterations in cellular and molecular mechanisms instigated by HS deficiency and subtending onset and growth of osteochondroma and how such changes could be targeted toward therapeutic ends. HME is a rare and orphan disease and, as such, is being studied only by a handful of clinical and basic investigators. Despite this limitation, significant advances have been made in the last few years, and the future bodes well for deciphering more thoroughly its pathogenesis and, in turn, identifying the most effective treatment for osteochondroma prevention.

Hereditary Multiple Exostoses: a review of clinical appearance and metabolic pattern

Hereditary multiple exostoses (HME) is an inherited genetic condition characterized by the presence of multiple exostoses (osteochondromas). MHE is a relatively rare autosomal dominant disorder, mainly caused by loss of function mutations in two genes: exostosin-1 (EXT1) and exostosin-2 (EXT2). These genes are linked to heparan sulfate (HS) synthesis, but the specific molecular mechanism leading to the disruption of the cartilage structure and the consequent exostoses formation is still not resolved. The aim of this paper is to encounter the main aspects of HME reviewing the literature, in order to improve clinical features and evolution, and the metabolic-pathogenetic mechanisms underlying. Although MHE may be asymptomatic, a wide spectrum of clinical manifestations is found in paediatric patients with this disorder. Pain is experienced by the majority of patients, even restricted motion of the joint is often encountered. Sometimes exostoses can interfere with normal development of the growth plate, giving rise to limb deformities, low stature and scoliosis. Other many neurovascular and associated disorders can lead to surgery. The most feared complication is the malignant transformation of an existing osteochondroma into a secondary peripheral chondrosarcoma, during adulthood. The therapeutic approach to HME is substantially surgical, whereas the medical one is still at an experimental level. In conclusion, HME is a complex disease where the paediatrician, the geneticist and the orthopaedic surgeon play an interchangeable role in diagnosis, research and therapy. We are waiting for new studies able to explain better the role of HS in signal transduction, because it plays a role in other bone and cartilage diseases (in particular malignant degeneration) as well as in skeletal embryology.