Fracture Patterns and Mortality in Osteopetrosis: A 7-year Retrospective Analysis from Türkiye's National Registry

BACKGROUND

The aim of this study is to determine the demographic data, fracture treatment methods, and medical treatments of patients diagnosed with osteopetrosis in the national registry.

METHODS

Patients with International Classification of Diseases (ICD)-10 code Q78.2 for osteopetrosis between January 1, 2016 and April 11, 2023 were retrospectively reviewed. Data on sex, age at time of diagnosis, fracture history, mortality, and use of medications were evaluated for all patients. In addition, open reduction and internal fixation, closed reduction and internal fixation, closed reduction and casting, and conservative treatment methods were noted. The number of patients requiring deformity surgery was determined. The incidence and prevalence of osteopetrosis were also calculated in this cross-sectional study.

RESULTS

A total of 476 patients diagnosed with osteopetrosis were identified. The mean age at time of diagnosis of these patients was 5.79 ± 5.43 years. A total of 101 patients died. As the age at diagnosis decreased, the mortality rate of the patients increased with statistical significance ( P <0.001). A total of 192 fractures were seen in 121 osteopetrosis patients in this study. Femur fractures were most common among these patients with osteopetrosis. A history of fracture was statistically significantly less common in patients using a combination of vitamin D + calcium compared with patients not using such medication ( P <0.001). In this 7-year cross-sectional study, the incidence was found to be 1 in 416,000 and the prevalence was 0.00199% in the population under 18 years of age.

CONCLUSION

Younger age at diagnosis is associated with higher mortality in patients with osteopetrosis. In addition, the combination of vitamin D and calcium were associated with lower fracture incidence.

LEVEL OF EVIDENCE

Prognostic Level II.

Successful complete oral rehabilitation of a patient with osteopetrosis with extensive pre-treatments, bone grafts, dental implants and fixed bridges: a multidisciplinary case report

BACKGROUND

Osteopetrosis comprises a group of inherited disorders that are rare and result in abnormal bone structure. Bone remodeling is extremely inhibited because osteoclasts are nonfunctional or lacking. This condition causes overgrowth of bone with disappearance of the bone marrow, leading to aplastic anemia; obstruction of nerve passages in the skull leads to blindness and often hearing impairment. In most cases, osteopetrosis results in oral complications such as tooth deformation, hypomineralization, and delayed or absent tooth eruption. The only curative treatment is hematopoietic stem cell transplantation (HSCT). The main treatment of the oral complications during childhood and adolescence consists in protecting the erupted teeth against caries disease through prophylactic treatment aimed at optimal oral hygiene through frequent regular dental visits throughout life. Many patients with osteopetrosis require major oral rehabilitation to treat complications of the disease. Improved results of HSCT increase the likelihood that dental professionals will encounter patients with osteopetrosis.

CASE PRESENTATION

In this case report, we show that individuals with osteopetrosis who have severe oral complications can be treated successfully if they are treated for osteopetrosis at an early age. The boy had his dental care in pedodontics, and regular multidisciplinary meetings were held for future treatment planning. At the age of 15, he was then referred for rehabilitation. The initial evaluations revealed no further growth in the alveolar bone. The rehabilitation was done stepwise, with extraction of malformed and malpositioned teeth. Initially, the patient received a removable partial denture followed by reconstruction of the width of the alveolar process, titanium implants, temporary fixed bridges, and finally screw-retained titanium-ceramic bridges with titanium frames for the upper and lower jaws.

CONCLUSIONS

The three-year follow-up after loading indicated a stable marginal bone level and optimal oral hygiene as a result of frequent professional oral hygiene care. The patient showed no signs of symptoms from the temporomandibular joint and has adapted to the new jaw relation without any functional or phonetical issues.

Prosthetic Management of Albers-Schönberg Disease with Osteomyelitis: A 10-Year Follow-up Case Report

Albers-Schönberg disease is a rare bone syndrome characterized by increased bone density and infectious complications after dental extraction or minor surgery. The prosthodontic management of such edentulous patients with osteomyelitis is very challenging and requires special strategies due to a high risk of failure and worsening of the condition. This clinical report describes the rehabilitation of a 31-year-old edentulous woman presenting with Albers-Schönberg disease, secondary chronic osteomyelitis, maxillary hypoplasia, compromised oral conditions, temporomandibular disorders, and psychologic distress. The treatment included a mandibulectomy and removable prostheses. A crucial element for the successful long-term treatment and quality of life improvement observed in this patient was the 1-year transitional phase with interim dentures and frequent follow-up appointments. The complications and management proposed during a 10-year follow-up are presented. Int J Prosthodont 2023;36:642-648.

Maxillary osteomyelitis in a young female with osteopetrosis: unveiling an uncommon connection

Osteopetrosis encompasses a spectrum of conditions marked by heightened bone density due to faulty osteoclast-mediated bone resorption, leading to an accumulation of immature bone and thickened cortical structures. This condition gives rise to bone fragility, blood cell irregularities, nerve entrapment and growth challenges, all stemming from disrupted bone remodelling. Craniofacial distinctiveness, encompassing anomalies in the skull and jaw, is a frequent occurrence. Osteopetrosis presents a range of clinical signs, including facial and dental anomalies. The diagnostic process involves thorough clinical and radiological assessments, often obviating the need for genetic testing. Interestingly, few prior reports have delved into the specifics of craniofacial and dental issues in osteopetrosis. The presented case showcases rare occurrence of maxillary osteomyelitis. The diagnosis was established through a combination of history, clinical, radiographic and laboratory findings. The patient declined surgical intervention, leading to the implementation of conservative management involving regular irrigation alongside systemic antibiotic therapy.

Case Report: Osteosclerotic metaphyseal dysplasia with optic nerve involvement and progressive osteonecrosis of the jaw due to a novel LRRK1 mutation

Background

Osteosclerotic metaphyseal dysplasia (OSMD, OMIM 615198) is an extremely rare autosomal recessive osteopetrosis disorder resulting in a distinctive pattern of osteosclerosis of the metaphyseal margins of long tubular bones. To date, only thirteen cases have been reported (eight molecularly confirmed). Five homozygous sequence variants in the leucine-rich repeat kinase 1 (LRRK1) gene have been identified to cause OSMD. We present two male siblings with OSMD with a novel LRRK1 variant.

Cases

The index case, now aged 6 years, was referred aged 9 months when diffuse sclerosis of the ribs and vertebral bodies, suggestive of osteopetrosis, was incidentally identified on a chest radiograph for suspected lower respiratory tract infection. Parents were consanguineous and of Pakistani origin. Further evaluation revealed developmental delay, nystagmus with bilateral optic nerve hypoplasia and severe visual impairment. Skeletal survey confirmed typical changes of OSMD, with widespread diffuse sclerosis and Erlenmeyer flask deformity of long bones. His older sibling, now aged 12 years, was 7 years at the time of referral and had similar clinical course and skeletal findings. Additionally, he had a chronic progressive osteonecrosis of the left mandible that required debridement, debulking and long-term antibiotics. Skeletal survey revealed findings similar to his sibling. Neither sibling had significant skeletal fractures or seizures. Unlike most previous reports suggesting sparing of the skull and lack of visual impairment, our patients had evidence of osteosclerosis of the cranium. Genetic screening for the common autosomal recessive and dominant pathogenic variants of osteopetrosis was negative. Whole Exome Sequencing (WES) followed by Sanger sequencing, identified a novel homozygous LRRK1 c.2506C>T p. (Gln836Ter) nonsense variant predicted to result in premature truncation of LRRK1 transcript.

Conclusion

Our cases confirm the autosomal recessive inheritance and expand the spectrum of genotype and phenotype of OSMD reported in the literature. Increasing reports of LRRK1 variants in this phenotype raise the question of whether LRRK1 should be included in targeted osteopetrosis panels. Bone histology in previous cases has shown this to be an osteoclast rich form of osteopetrosis raising the possibility that haematopoietic stem cell transplantation may be an appropriate treatment modality.

Osteopetrosis with Arnold Chiari malformation type I

Osteopetrosis is a rare genetic disorder resulting in increased bone density and decreased bone remodelling. Bone expansion results in the crowding of neural foramina causing cranial nerve compression. Here, we describe a female infant in her mid infancy presented with no eye contact since birth, and abdominal distension for 2 months. On CT evaluation, sclerotic bones with bilateral optic canal narrowing were present. A crowded posterior fossa with Arnold Chiari type I malformation was seen on MRI evaluation, suggesting a rare association of osteopetrosis with Arnold Chiari's malformation.

Pediatric patient with a bilateral Salter-Harris II fracture and slipped capital femoral epiphysis secondary to autosomal recessive osteopetrosis

Treatment of femoral neck fractures secondary to osteopetrosis is an uncertain and puzzled decision. Experience in the treatment, especially in the pediatric population, is scarcely reported. The duration of conservative treatment is prolonged and poses the risks of non-union and development of coxa vara deformity. The recommended treatment is closed reduction and internal fixation; however, surgery on osteopetrotic bone is challenging due to defective bone marrow function, delayed consolidation and higher risk of intraoperative fractures. Slipped capital femoral epiphysis secondary to osteopetrosis is very rarely reported. This article presents the case of a 5-year-old female patient with rapidly deteriorating physical function due to bilateral proximal femoral Salter-Harris type II fractures with associated slippage of the growth plates secondary to confirmed autosomal recessive osteopetrosis. Operative treatment was performed in a tertiary level orthopedic center with closed reduction and internal fixation with cannulated screws. A loss of fixation with coxa vara deformity was seen on the left side 7 months postoperatively with increasing pain. A revision surgery with reosteosynthesis and a valgus osteotomy was thus performed which showed good subjective and objective results 1 year postoperatively with complete bony union.

Malignant infantile osteopetrosis in a 3-year-old Yemeni child: a case report

Infantile malignant osteopetrosis (IMOP) is a rare bone resorptive disorder with an autosomal recessive inheritance pattern. It is characterized by increased bone density due to osteoclastic failure in differentiation or function. The clinical manifestations of IMOP start at birth or infancy with varied rings according to the type and degree of osteopetrosis. We presented a 3-year-old female patient referred to us due to chronic anaemia six months ago. The physical examination revealed hepatosplenomegaly, axial hypotonia, and visual impairment. Blood investigation revealed pancytopenia and hypocalcemia. Radiologic studies revealed a generalized increase in bone density, abnormal metaphyseal remodelling, and rain atrophy. The bone marrow aspiration (BMA) shows dry tap and hypocellularity of all cell lines. IMOP was diagnosed depending on clinical, radiologic, and BMA results. In conclusion, IMOP is relatively uncommon. Accurate diagnosis should be made through clinical, BMA, and radiologic investigations, especially in a resource-limited setting, as performed in our case.

[A rare case of bilateral femoral neck fracture in a 5-year-old girl with autosomal dominant osteopetrosis type 2]

The rare case of a 5‑year-old girl with autosomal dominant osteopetrosis type 2, who suffered metaphyseal fractures of the femoral neck on both sides within 6 months is described. On the right side, the diagnosis was made 3 months after the onset of symptoms, so that a coxa vara occurred. The treatment was surgically treated through a valgus osteotomy with fixation of the femoral head with K‑wires. Three months after the operation, the girl complained of a painful restriction of movement on her left side. Radiologically, a metaphyseal femoral neck fracture without coxa vara was diagnosed and in situ fixated with 2 K wires. Two months after the second operation, there was a symmetrical free range of motion of the hips with no symptoms. The metaphyseal femoral neck fracture with verticalization of the growth plate is a serious disease in autosomal dominant osteopetrosis due to the development of a coxa vara, which, if diagnosed at an early stage, can be treated well with in situ fixation. If the coxa vara has already developed, a valgus osteotomy should be performed despite the risk of delayed bone healing.

Neonatal hydrocephalus: an atypical presentation of malignant infantile osteopetrosis

PURPOSE

Autosomal recessive osteopetrosis has a variable presentation, most commonly including failure to thrive, hypocalcemia, seizures, hepatosplenomegaly, hydrocephalus, vision or hearing loss, and cytopenias. Multiple symptoms are usually seen at presentation. The variability of presentation often delays diagnosis and subsequent treatment. Here, we present a case of an infant with this condition who initially presented with triventricular hydrocephalus with Chiari I malformation. This alone is not a common presentation of this disease, and we present this case to highlight autosomal recessive osteopetrosis as a potential diagnosis in infants presenting with hydrocephalus and discuss the other associated symptoms, management, and prognosis of this condition.

CASE REPORT

The patient was a full-term infant with a routine newborn period. At 6 months, the infant had macrocephaly and frontal bossing with a bulging fontanelle. She was found to have hydrocephalus with moderate ventriculomegaly involving the third and lateral ventricles with an associated Chiari 1 malformation. The infant was asymptomatic at the time. The infant was promptly referred to neurosurgery and underwent an uncomplicated ventriculoperitoneal shunt placement. Post-operative X-rays showed increased density of the skull with other bone changes suggestive of autosomal recessive osteopetrosis. Subsequent lab work and imaging studies were consistent with this condition. The diagnosis was confirmed by genetic testing, and the patient has undergone treatment with hematopoietic stem cell transplant.

CONCLUSION

Hydrocephalus is a common feature of this condition, typically seen in conjunction with other systemic symptoms and laboratory findings. Our patient had a limited initial presentation of triventricular hydrocephalus with Chiari I malformation and was otherwise clinically asymptomatic. There is limited literature of such a presentation, and we highlight this case to increase awareness, as timely diagnosis of these patients is critical for treatment and future outcomes.

Surgical-orthodontic treatment for severe malocclusion in a patient with osteopetrosis and bilateral cleft lip and palate

Orthognathic surgery in patients with craniofacial osteopetrosis, a condition associated with osteoclast dysfunction, is usually avoided because of the risk of osteomyelitis. A 19-year-old woman presented with the chief complaint of severe malocclusion and anterior crossbite. After radiographic evaluation, craniofacial osteopetrosis was diagnosed. Surgical-orthodontic treatment was performed after meticulous history taking and verification of normal bone turnover using bone-metabolism markers for endocrine evaluation. Favorable esthetic and functional outcomes were achieved.

Total Hip Arthroplasty in Patients With Osteopetrosis

BACKGROUND

Osteopetrosis is an inherited bone disease associated with high risk of osteoarthritis and fracture non-union, which can lead to total hip arthroplasty (THA). Bone quality and morphology are altered in these patients, and there are limited data on results of THA in these patients. The goals of this study were to describe implant survivorship, clinical outcomes, radiographic results, and complications in patients with osteopetrosis undergoing primary THA.

METHODS

We identified 7 patients (9 hips) with osteopetrosis who underwent primary THA between 1970 and 2017 utilizing our total joint registry. The mean age at index THA was 48 years and included two males and five females. The mean follow-up was 8 years.

RESULTS

The 10-year survivorship free from any revision or implant removal was 89%, with 1 revision and 1 resection arthroplasty secondary to periprosthetic femoral fractures. The 10-year survivorship free from any reoperation was 42%, with 4 additional reoperations (2 ORIFs for periprosthetic femoral fractures, 1 sciatic nerve palsy lysis of adhesions, 1 hematoma evacuation). Harris hip scores significantly increased at 5 years (P = .04). Five hips had an intraoperative acetabular fracture, and 1 had an intraoperative femur fracture. All postoperative femoral fractures occurred in patients with intramedullary diameter less than 5 mm at a level 10 cm distal to the lesser trochanter.

CONCLUSION

Primary THA in patients with osteopetrosis is associated with good 10-year implant survivorship (89%), but a very high reoperation (58%) and periprosthetic femoral fracture rate (44%). Femoral fractures appear associated with smaller intramedullary diameters.

Further understanding on osteopetrotic femoral fractures: a case report and literature review

BACKGROUND

Osteopetrosis is a genetic disease characterized by defects in osteoclast formation and function. There were a few cases of subtrochanteric femur fractures treated with dynamic hip screw (DHS) in patients with osteopetrosis, but unfortunately the healing outcome was rather poor.

CASE PRESENTATION

We present our experience for treating a patient with intermediate autosomal recessive osteopetrosis (IRO) suffering from subtrochanteric femur fracture. In this case, we successfully used dynamic hip screw (DHS) internal fixation through meticulous preoperative planning and postoperative care, as well as application of surgical techniques. The patient displayed stable internal fixation with no limitation of activities during follow-up for 15 months. In addition to this case, a review of previous case reports showed an increasing number of case reports demonstrating that surgical treatment-related complications could be avoided preoperatively, intraoperatively, and postoperatively.

CONCLUSION

DHS for this patient, who suffered from subtrochanteric fractures with osteopetrosis, was successfully implemented. In the light of a comprehensive literature review, preoperative planning, surgical techniques, and postoperative rehabilitation care can significantly reduce the complications.

A Homozygous Mutation in 5' Untranslated Region of TNFRSF11A Leading to Molecular Diagnosis of Osteopetrosis Coinheritance With Wiskott-Aldrich Syndrome

Wiskott-Aldrich syndrome (WAS) and osteopetrosis are 2 different, rare hereditary diseases. Here we report clinical and molecular genetics investigations on an infant patient with persistent thrombocytopenia and prolonged fever. He was clinical diagnosed as osteopetrosis according to clinical presentation, radiologic skeletal features, and bone biopsy results. Gene sequencing demonstrated a de novo homozygous mutation in 5'-untranslated region of TNFRSF11A, c.-45A>G, which is relating to osteopetrosis. Meanwhile, a hemizygous transition mutation in WAS gene, c.400G>A diagnosed the infant with WAS. This is the first clinical report for the diagnosis of osteopetrosis coinheritance with WAS in a single patient.

Intramedullary nailing for subtrochanteric fracture in autosomal dominant Type II osteopetrosis: Case report of 2 patients

RATIONALE

Autosomal dominant type II (AD II) osteopetrosis is a rare inheritable metabolic bone disease characterized by hard but brittle bone and a narrow medullary canal. Intramedullary nailing (IMN) is a difficult but attractive option for the treatment of subtrochanteric fractures in patients with AD II osteopetrosis.

PATIENT CONCERNS AND DIAGNOSIS

Two patients with AD II osteopetrosis sustained subtrochanteric fractures after a fall.

INTERVENTIONS

IMN was performed through the sequential use of instruments such as a 4.9-mm drill bit, small reamer, and larger reamer for over-reaming.

OUTCOMES

In the first case, IMN left some gap at the fracture site. Dynamization was performed to treat the delayed union at 6 months postoperatively. The fracture healed at 10 months after the dynamization. In the second case, IMN was successful without a gap, and the fracture healed at 8 months.

LESSONS

Although IMN is difficult to perform owing to partial obliteration of the medullary canal in AD II osteopetrosis, it can be performed with sequential widening of the medullary canal using various instruments. In addition, the fracture gap should not be left uncorrected during IMN to attain fracture union.

Pleomorphic Sarcoma in a Patient with Osteopetrosis

Osteopetrosis comprises a rare, heterogeneous group of heritable conditions that are characterized by a defect in bone resorption by osteoclasts. We report the case of a 53-year-old woman with previously undiagnosed osteopetrosis who presented with a pathologic proximal humeral fracture secondary to pleomorphic sarcoma, which is previously undescribed in the English literature. Management of the primary lesion necessitated ablative surgery, but the malignancy nonetheless was associated with rapidly progressive metastatic disease.

Osteomyelitis of the mandible secondary to malignant infantile osteopetrosis in an adult

Malignant infantile osteopetrosis (MIOP), an autosomal-recessive disorder, is extremely rare, presenting early in life with extreme sclerosis of the skeleton and reduced activity of osteoclasts. It was first described by Albers Schonberg in 1904. Disease manifestations include compensatory extramedullary haematopoiesis at sites such as the liver and spleen, hepatosplenomegaly, anaemia and thrombocytopaenia. Neurological manifestations can also occur due to narrowing of osseous foramina resulting in visual impairment, hearing loss, facial palsy and hydrocephalus. In addition, growth retardation and recurrent infections requiring long-term antibiotic use are common. The incidence of MIOP is 1/2 000 000 and if untreated, then it has a fatal outcome, with the majority of cases occurring within the first 5 years of life. At present, the only potentially curative option is a haematopoietic stem cell transplant. We present a 21-year-old woman, diagnosed with malignant infantile osteopetrosis, due to a mutation in the T-cell immune regulator 1 gene when aged 6 weeks, presenting with chronic osteomyelitis of her left mandible. As malignant infantile osteopetrosis has a high mortality in infancy, we felt it prudent to report this rare case in a patient surviving to adulthood.

Bilateral endoscopic optic nerve decompression in an infant with osteopetrosis

Osteopetrosis is a rare disorder of bone remodeling characterized by defective resorption leading to excessive skeletal mass including optic canal. Compression of the optic nerve from the narrowed optic canal is the most common cause of vision loss in children with osteopetrosis. We report the case of a 6-month old girl with osteopetrosis who underwent bilateral optic canal decompression via endoscopic transcaruncular approach for progressive deterioration of visual function secondary to compressive optic neuropathy from narrowed optic canals. The patient showed improvement in visual function postoperatively.

Comparison of Optic Canal Diameter in Children With Malignant Infantile Osteopetrosis and Normal Children and the Effects of Hematopoietic Stem Cell Transplantation on the Optic Canal Diameter

PURPOSE

To investigate the difference in the optic canal diameter between children with autosomal recessive malignant infantile osteopetrosis and normal children, and to assess the influence of hematopoietic stem cell transplantation on the optic canal diameter.

METHODS

Twenty pediatric patients with malignant infantile osteopetrosis and 22 normal control children were included in this study. Eleven patients with malignant infantile osteopetrosis underwent hematopoietic stem cell transplantation. The measurements included optical canal diameter and flash visual evoked potential. Comparisons of these measurements between patients with malignant infantile osteopetrosis and normal controls as well as before and after hematopoietic stem cell transplantation were performed. The correlation between age and optic canal diameter was analyzed using Pearson correlation analysis.

RESULTS

The mean optic canal diameter before hematopoietic stem cell transplantation was 1.65 ± 0.54 mm in patients with malignant infantile osteopetrosis and 3.38 ± 0.60 mm in the control group (P < .001). The mean optic canal diameter after hematopoietic stem cell transplantation was 2.72 ± 0.66 mm, which was significantly different from the pre-transplantation measurement (P < .001). The P2 latency for the flash visual evoked potential after hematopoietic stem cell transplantation (152.3 ± 36.4 ms) was significantly less than that before transplantation (165.5 ± 27.7 ms; P = .051). Pearson correlation analysis revealed a significant correlation between age and optic canal diameter (r = 0.722, P < .001).

CONCLUSIONS

The optic canal was narrower in pediatric patients with malignant infantile osteopetrosis than in age-matched normal controls. This condition can be relieved through hematopoietic stem cell transplantation and the impaired conductibility of the optic nerve can be improved in some cases. [J Pediatr Ophthalmol Strabismus. 2019;56(1):35-42.].

The Use of Distraction Osteogenesis and a Taylor Spatial Frame in the Treatment of a Tibial Shaft Nonunion and Deformity in a Pediatric Patient with Osteopetrosis: A Case Report

CASE

Osteopetrosis is a heritable disease that causes brittle bones that are prone to fracture. Furthermore, these brittle bones have a poor healing response and a high risk of subsequent refracture. Many treatment strategies have been described for initial fracture stabilization; however, there is a paucity of literature describing treatment of refractures and subsequent deformity. We present the long-term results of a unique case in which we used a circular external fixator, the TAYLOR SPATIAL FRAME (Smith & Nephew), to correct a deformity in a patient with osteopetrosis who suffered multiple refractures of the tibia.

CONCLUSION

We propose the potential use of distraction osteogenesis as an option for fracture and deformity treatment in patients with osteopetrosis.

Effects of hypothalamic leptin gene therapy on osteopetrosis in leptin-deficient mice

Impaired resorption of cartilage matrix deposited during endochondral ossification is a defining feature of juvenile osteopetrosis. Growing, leptin-deficient ob/ob mice exhibit a mild form of osteopetrosis. However, the extent to which the disease is (1) self-limiting and (2) reversible by leptin treatment is unknown. We addressed the first question by performing histomorphometric analysis of femurs in rapidly growing (2-month-old), slowly growing (4-month-old) and skeletally mature (6-month-old) wild-type (WT) and ob/ob male mice. Absent by 6 months of age in WT mice, cartilage matrix persisted to varying extents in distal femur epiphysis, metaphysis and diaphysis in ob/ob mice, suggesting that the osteopetrotic phenotype is not entirely self-limiting. To address the second question, we employed hypothalamic recombinant adeno-associated virus (rAAV) gene therapy to restore leptin signaling in ob/ob mice. Two-month-old mice were randomized to one of the three groups: (1) untreated control, (2) rAAV-Leptin or (3) control vector rAAV-green fluorescent protein and vectors injected intracerebroventricularly. Seven months later, rAAV-leptin-treated mice exhibited no cartilage in the metaphysis and greatly reduced cartilage in the epiphysis and diaphysis. At the cellular level, the reduction in cartilage was associated with increased bone turnover. These findings (1) support the concept that leptin is important for normal replacement of cartilage by bone, and (2) demonstrate that osteopetrosis in ob/ob mice is bone-compartment-specific and reversible by leptin at skeletal sites capable of undergoing robust bone turnover.

Decompressive Cranioplasty in a Patient with Osteopetrosis

BACKGROUND

Osteopetrosis is a heterogeneous group of uncommon congenital disorders that causes bony sclerosis and remodeling. Patients who are symptomatic can show significant neurologic consequences with the involvement of cranial nerves and symptoms of increased intracranial pressure (ICP).

CASE DESCRIPTION

We report an unusual case of a 26-year-old woman with an autosomal-dominant type of osteopetrosis who presented with headache and severe visual deterioration, both attributed to increased ICP. A hemicranioplasty was preformed, resulting in the resolution of her symptoms of ICP and stabilization of her vision. Postoperative imaging showed expansion of the ventricles and the subarachnoid spaces with an improvement of the associated cerebellar herniation.

CONCLUSIONS

In conclusion, in patients with symptomatic osteopetrosis, cranioplasty can be considered as an option to treat high ICP-related symptoms.

Successful open reduction and internal fixation for displaced femoral fracture in a patient with osteopetrosis: Case report and lessons learned

RATIONALE

Osteopetrosis is a rare disease that predominantly occurs in descendants of inbreeding families. In the case of fractures happen in patients with osteopetrosis, the choice between operative or conservative treatment is still controversial. Open reduction and internal fixation (ORIF) is a conventional treatment for fractures, and it possesses more applicability than conservative treatment. During this surgical treatment, ensure that bone union in the right way is pivotal to success and simultaneously prevents refracture and displacement after the operation. Herein, we present a case of femoral fracture of a patient with osteopetrosis via open reduction and internal fixation. To illustrate successful factors during the treatment process, we discuss experience combined with literature review following case report.

PATIENT CONCERNS

A 67-year-old man who has diagnosed with osteopetrosis over 20 years ago suffered from pain in the left hip last for more than 1 month and he was incapable of walking recently. Before this incident, he had sustained 4 femoral fractures that treated insufficiently by open reduction surgery.

DIAGNOSIS

Physical, radiological, and biological examinations indicated a femoral subtrochanteric fracture that was overlapping displacement between fracture ends.

INTERVENTIONS AND OUTCOMES

Treated with surgery by open reduction with internal fixation and osteotomy, the fracture united in 12 months, and he returned to walk with full weight bearing, during which no complication occurred.

LESSONS

Open reduction and internal fixation is also suitable for the patient with osteopetrosis, and they have similar union ability to the normal. To guarantee successful treatment, specific strategies of operation and rehabilitation program are necessary.

Phenotypic severity of autosomal dominant osteopetrosis type II (ADO2) mice on different genetic backgrounds recapitulates the features of human disease

Autosomal dominant osteopetrosis type II (ADO2) is a heritable osteosclerotic bone disorder due to dysfunctional osteoclast activity. ADO2 is caused by missense mutations in the chloride channel 7 (CLCN7) gene characterized by osteosclerosis with multiple fractures. ADO2 can result in osteomyelitis, visual loss and bone marrow failure. Currently, there is no cure for ADO2, and until recently no appropriate animal model of ADO2 existed to understand better the pathogenesis of this disease and to test new therapies. Therefore, we created ADO2 knock-in mouse model with a G213R (human homolog of G215R) missense mutation in the Clcn7 gene on 129S1 background, and demonstrated that this mouse model phenocopies human ADO2. As ADO2 gives rise to incomplete penetrance (66%) in human and marked phenotypic variability is observed among patients with the same mutation, we hypothesized that the severity and penetrance of ADO2 will also vary in mouse models on different genetic backgrounds. To test this, we created ADO2 mouse models in DBA/D2, C57BL/6J/B6 and Balb/c strains, and compared bone phenotypes and performed serum biochemical analysis between strain- and age-matched wild-type (WT) and ADO2 mice. At 3months of age, whole body aBMD was higher (4-7% in male; 1-5% in female) in the ADO2 mice compared to their wild-type littermates. In addition, ADO2 male mice on 129 background displayed highest percent increase of BV/TV (106%), followed by D2 (92%), B6 (46%), and Balb/c (33%) compared to strain-matched wild-type mice. We observed similar differences for BV/TV between ADO2 and wild-type mice on different genetic backgrounds in female: 129 (96%)>D2 (73%)>Balb/c (39%) and B6 (36%). Serum calcium, phosphorus, alkaline phosphatase and P1NP levels were similar in the WT and ADO2 mice on all genetic backgrounds but TRAP was higher (76% to 220% in male; 33-95% in female) and CTX/TRAP ratio was lower (39-65% in male and 3-41% in female) in the ADO2 mice compared to their strain-matched wild-type littermates. We also found that young (3months) ADO2 mice on 129S1 background exhibited 200% higher trabecular BV/TV whereas old (18months) ADO2 mice displayed 400-700% higher BV/TV compared to their age-matched wild-type controls. In summary, phenotypic severity in ADO2 mice varied markedly on different genetic backgrounds (129>D2>Balb/c>B6) and became more pronounced with age, which resembles the wide variations in phenotype observed in ADO2 patients. These mouse models will help us to identify genes/factors that influence severity and penetrance of ADO2, and test innovative therapies to treat this disease.

Dealing with sub-trochanteric fracture in a child with osteopetrosis : A case report

Osteopetrosis is a rare hereditary condition which may have autosomal recessive or autosomal dominant inheritance. Patients tend to present most commonly with fractures but involvement of cranial nerves and hematopoetic system is not uncommon. Patients with infantile and intermediate type tend to present more often with problems other than orthopaedic problems. While diagnosis can be made on the basis of radiographs, management needs to be customized for every patient. Non operative and operative management both have their advantages and disadvantages. We are here reporting a case of sub-trochanteric fracture in an eight-year-old child which was managed successfully with a dynamic hip screw (DHS). Surgery could be performed successfully by taking precautions during reduction, drilling and screw placement. At the latest follow up, which was after one and half years of surgery, the fracture had united well and the child faced no limitations of activities. Thus, open reduction and fixation with DHS can be considered as an effective management modality for pediatric sub-trochanteric fractures in osteopetrosis.

Disabling Osteopetrosis in an Young Lady

Osteopetrosis is a rare disorder of osteoclastic bone resorption leading to hyperostosis. Albers-Schonberg disease, an autosomal dominant variant of osteopetrosis occurs in young adults and has a benign course. A 17 year old female presented with generalized weakness and pallor for last two months. She had insidious onset and gradually progressive loss of vision and hearing for last two years. Plain x-ray of skull revealed increased radio-opacity of skull bones specially in the base, severe under-pneumatization of frontal and sphenoidal sinuses. Maxillary and ethmoid sinuses were also opaque and under-pneumatised. Bone scintigraphy with technetium-99m methylene diphosphonate showed diffusely increased uptake in whole skull. Bone marrow biopsy revealed a reactive marrow with areas of fibrosis without any evidence of granuloma or malignancy. The case had cranial entrapment neuropathies and severe anaemia due to osteopetrosis. High level of awareness is needed to diagnose the case properly and to help the patient to cope with the disabling features of the disease.

Ultrastructural Analyses of Alveolar Bone in a Patient With Osteomyelitis Secondary to Osteopetrosis: A Review of the Literature

Osteopetrosis is a generic term for generalized sclerotic conditions caused by rare genetic disorders. Decreased osteoclastic activities disturb bone remodeling, resulting in greater mineral density and greater compressive strength; therefore, bone fracture is a major physical symptom of osteopetrosis. Osteomyelitis of the maxilla or mandible is a common and well-documented complication of osteopetrosis. Local infection, such as odontogenic infection, is more likely to lead to osteomyelitis, and treatment strategies can be challenging. However, detailed ultrastructural analyses of bone from patients with osteopetrosis and odontogenic infection are limited. This report describes a case of osteomyelitis of the maxilla and mandible secondary to osteopetrosis in an adult patient and presents ultrastructural data of alveolar bone tissue analyzed by contact microradiography, electron probe microanalysis, and x-ray diffraction. Cases of osteomyelitis of the jaw secondary to osteopetrosis also are reviewed.

Dental implants and osteomyelitis in a patient with osteopetrosis

Osteopetrosis (OP) is a rare genetic metabolic bone disorder characterized by osteoclast dysfunction impairing bone resorption. Together with normal osteoblastic activity this dysfunction promotes intense bone sclerosis with reduction of marrow spaces as well as bone turnover. Maxillofacial complications are common after tooth extraction. Osteomyelitis (OM) of the mandible occurs in around 10% of the cases with OP. The purpose of this paper is to report the fi rst case of OP treated with dental implants, and to describe the protocol used to treat OM that developed after failure of one implant. The treatment of OM included long-term use of antibiotics and marginal bone resection with a piezoelectric device. Similar cases to confirm the efficacy of this treatment are required.

Infantile osteopetrosis associated with osteomyelitis

Osteopetrosis is a rare inherited disorder characterised by the inability to reabsorb and remodel bone due to an osteoclast dysfunction. An increase in bone mass and density results in severe skeletal malformation and bone marrow failure, which may be fatal. The aim of this study was to report a case of infantile osteopetrosis in a 6-year-old boy, who primarily complained of dental problems. The patient developed an osteomyelitis after a primary tooth extraction. We also reviewed the literature about this genetic bone disease, since the management of dental problems of these patients can be a challenge to the dentist. The diagnosis, clinical and radiographic features and treatment of the case were discussed in this work.

[Femoral neck fracture in a patient with osteopetrosis]

Osteopetrosis is a rare hereditary bone disease characterized by increased bone density. Patients with adult osteopetrosis are often diagnosed incidentally by X-ray or on the presence of recurrent fractures. Internal fixations of fractures in patients with osteopetrosis are challenging due to the increased bone density, and special surgical equipment is often necessary. Non-union and malunion occur frequently making close post-operative monitoring important. We present a case of adult osteopetrosis with a femoral neck fracture.

Osteopetrosis: a Case of 'Hostile Chest' Associated with Symptomatic Aortic Valve Stenosis

Osteopetrosis is a heterogeneous group of heritable conditions in which there is a defect in bone resorption by osteoclasts. It is associated with an increased skeletal mass due to abnormally dense, but brittle, bones. Osteopetrosis varies greatly in severity, and fracture treatment remains a matter of controversy due to altered responses to fixation and the risk of osteomyelitis. The fate of sternotomy in this condition is unknown, and osteopetrosis could represent a situation of 'hostile chest'. Here, the case is described of a patient with osteopetrosis and concomitant symptomatic aortic valve stenosis and coronary artery disease.

A Practical Approach to Hypocalcaemia in Children

Hypocalcaemia is one of the commonest disorders of mineral metabolism seen in children and may be a consequence of several different aetiologies. These include a lack of secretion or function of parathyroid hormone, disorders of vitamin D metabolism and abnormal function of the calcium-sensing receptor. A practical approach to the investigation, diagnosis and subsequent management of hypocalcaemic disorders is presented.

ClC-7 expression levels critically regulate bone turnover, but not gastric acid secretion

Mutations in the 2Cl(-)/1H(+)-exchanger ClC-7 impair osteoclast function and cause different types of osteoclast-rich osteopetrosis. However, it is unknown to what extent ClC-7 function has to be reduced to become rate-limiting for bone resorption. In osteoclasts from osteopetrosis patients expression of the mutated ClC-7 protein did not correlate with disease severity and resorption impairment. Therefore, a series of transgenic mice expressing ClC-7 in osteoclasts at different levels was generated. Crossing of these mice with Clcn7(-/-) mutants rescued the osteopetrotic phenotype to variable degrees. One resulting double transgenic line mimicked human autosomal dominant osteopetrosis. The trabecular bone of these mice showed a reduction of osteoblast numbers, osteoid, and osteoblast marker gene expression indicative of reduced osteoblast function. In osteoclasts from these mutants ClC-7 expression levels were 20 to 30% of wildtype levels. These reduced levels not only impaired resorptive activity, but also increased numbers, size and nucleus numbers of osteoclasts differentiated in vitro. Although ClC-7 was expressed in the stomach and PTH levels were high in Clcn7(-/-) mutants loss of ClC-7 did not entail a relevant elevation of gastric pH. In conclusion, we show that in our model a reduction of ClC-7 function by approximately 70% is sufficient to increase bone mass, but does not necessarily enhance bone formation. ClC-7 does not appear to be crucially involved in gastric acid secretion, which explains the absence of an osteopetrorickets phenotype in CLCN7-related osteopetrosis.

Association of possible osteopetrosis with acute myeloid leukaemia in a child

Osteopetrosis is a rare disease characterised by an increase in bone mass, skeletal malformations and bone marrow failure due to defective bone resorption. We report a 3-month-old male child presented with chest infections, failure to thrive and hepatosplenomegaly and diagnosed with osteopetrosis associated with acute myeloid leukaemia M3 type (AML-M3). The patient died on day 7 of admission due to respiratory failure. To our knowledge, this is the first case where both osteopetrosis and AML is diagnosed in a patient.

Simple reproducible technique in treatment for osteopetrotic fractures

Osteopetrosis is a rare skeletal condition first described by German radiologist Heinrich Albers-Schonberg. The most important technical difficulty is drilling due to hard bone in patients with osteopetrosis; recommendations have been made to use high-speed electric drill bits. But, the unavailability of this special drill bit in most of the centres makes the job more difficult. The study was conducted from 2009 to 2012; the cases are selected from Outpatients Department of Postgraduate Institute of Medical Education and Research. The patients were in the age group of 10-50 years with a mean age of 26 years. Five cases were included in the study: four patients had subtrochanteric fractures, and one had segmental fracture of the humerus. Open reduction and internal fixation was done in all the fractures using metal-cutting drill bit. The use of metal-cutting drill bit in osteopetrosis not only made our job easy but also prevented thermal necrosis of the bone to a large extent. The union rate was 100 % in our series, and there was no infection in any of our cases. In the treatment for fractures in osteopetrosis, the use of a metal-cutting drill bit along with careful attention to drilling technique can help avoid bit breakage and thermal bone injury that may produce ring sequestrum or destroy the already scant osteogenic cells.

Infantile malignant osteopetrosis: report of 2 cases with osteomyelitis of the jaws

Infantile malignant osteopetrosis (IMO) is an uncommon autosomal recessive disease characterized by dense, brittle, sclerotic, radiopaque bones, which generally results in neurological and hematological abnormalities. In general, IMO is fatal, as patients fail to grow and expire due to complications of the disease such as severe chronic anemia, bleeding, and/or infections. In children with IMO, the development of the dentition is seriously disturbed. Patients with infantile osteopetrosis have a variety of signs and symptoms, including osteomyelitis of the jaws, which frequently and generally resists treatment. Infections may eventually become lethal; hence, jaw infection control is an important aspect of the disease for dentists and oral surgeons to consider. The purpose of this case report was to present 2 rare cases of pediatric patients (one of them died due to respiratory failure at 10 years old) diagnosed with osteopetrosis complicated by osteomyelitis of the jaw.

Successful staged hip replacement in septic hip osteoarthritis in osteopetrosis: a case report

BACKGROUND

Osteopetrosis is a rare, inherited, bone disorder, characterized by osteosclerosis, obliteration of the medullary cavity and calcified cartilage. The autosomal dominant form is compatible with a normal life span, although fractures often result from minimal trauma, due to the pathologic nature of bone. Osteomyelitis is common in patients with osteopetrosis because of a reduced resistance to infection, attributed to the lack of marrow vascularity and impairment of white cell function. Only one case of osteomyelitis of the proximal third of the femur has been previously reported, treated with several repeated debridements and finally with femoral head resection. Here we present for the first time a case of a staged implant of a cementless total hip prosthesis for the treatment of a septic hip in femoral neck nonunion in osteopetrosis.

CASE PRESENTATION

A 36-years-old woman, affected by autosomal dominant osteopetrosis was referred to our department because of a septic hip arthritis associated with femoral neck septic non-union, with draining fistulas. The infection occurred early after a plate osteosynthesis for a closed perthrocanteric fracture of the femur and persisted in spite of osteosynthesis removal, surgical debridement and external fixation. In our hospital the patient underwent accurate debridement, femoral head and greater trochanter resection, preparation of the diaphyseal intramedullary canal and implant of an antibiotic-loaded cement spacer. The spacer was exchanged after one month, due to infection recurrence and four months later, a cementless total hip arthroplasty was implanted, with no clinical and laboratory signs of infection recurrence at two years follow-up.

CONCLUSIONS

In case of hip septic arthritis and proximal femur septic non-union, femoral head resection may not be the only option available and staged total hip arthroplasty can be considered.

Oligodontia associated with osteopetrosis: a rare case report

Osteopetrosis is a descriptive term that refers to a group of rare hereditary disorders of the skeleton characterized by increased density of the bones. It was first described in 1904 by Albers-Schonberg, a German radiologist. This disease varies greatly in its presentation and severity ranging from neonatal onset with life threatening conditions such as bone marrow failure to incidental finding of osteopetrosis on radiographs. Dental abnormality may be attributed to pathological changes in the bone. Dentists should be aware of patients with the disease because of its effect on osteoclast function which results in impaired wound healing. This paper presents the case of a five-year-old girl exhibiting oligodontia associated with osteopetrosis.

Dental management in autosomal recessive (intermediate) osteopetrosis: a case report

Osteopetrosis (Albers-Schonberg disease) is the name given to a group of diseases that affect the growth and remodeling of bones. It is characterized by overgrowth and sclerosis of bone, resulting in thickening and narrowing of the marrow cavities throughout the skeleton. The exact cause is unknown, although failure of bone resorption related to defective osteoclasts is considered to be the basis of the problem. These patients present a significant challenge to the dentist for management of jaw and dental problems, as the disease process demands special strategies which are often at variance with conventional dentistry. The purpose of this paper was to report the management and follow-up of a child with intermediate autosomal recessive osteopetrosis who primarily complained of dental problems.

Dysosteosclerosis presents as an "osteoclast-poor" form of osteopetrosis: comprehensive investigation of a 3-year-old girl and literature review

Dysosteosclerosis (DSS), an extremely rare dense bone disease, features short stature and fractures and sometimes optic atrophy, cranial nerve palsy, developmental delay, and failure of tooth eruption in infancy or early childhood consistent with osteopetrosis (OPT). Bone histology during childhood shows unresorbed primary spongiosa from deficient osteoclast action. Additionally, there is remarkable progressive flattening of all vertebrae and, by adolescence, paradoxical metaphyseal osteopenia with thin cortical bone. Reports of consanguinity indicate autosomal recessive inheritance, yet more affected males than females suggest X-linked recessive inheritance. We investigated a nonconsanguineous girl with DSS. Osteosclerosis was discovered at age 7 months. Our studies, spanning ages 11 to 44 months, showed weight at approximately 50th percentile, and length diminishing from approximately 30th percentile to -2.3 SD. Head circumference was +4 SD. The patient had frontal bossing, blue sclera, normal teeth, genu valgum, and unremarkable joints. Radiographs showed orbital and facial sclerosis, basilar thickening, bone-in-bone appearance of the pelvis, sclerotic long bone ends, and fractures of ribs and extremities. Progressive metaphyseal widening occurred as vertebrae changed from ovoid to flattened and became beaked anteriorly. A hemogram was normal. Consistent with OPT, serum parathyroid hormone (PTH) concentrations reflected dietary calcium levels. Serum bone alkaline phosphatase, osteocalcin, and TRACP-5b were subnormal. The iliac crest contained excessive primary spongiosa and no osteoclasts. No mutations were identified in the splice sites or exons for the genes encoding chloride channel 7, T-cell immune regulator 1, OPT-associated transmembrane protein 1, and monocyte colony-stimulating factor (M-CSF) and its receptor C-FMS, ANKH, OPG, RANK, and RANKL. Genomic copy-number microarray was unrevealing. Hence, DSS is a distinctive OPT of unknown etiology featuring osteoclast deficiency during early childhood. How osteopenia follows is an enigma of human skeletal pathobiology.

[Albers-Schönberg's disease with ocular manifestation]

Albers-Schönberg's disease is a rare disease (one case in 100,000 inhabitants), asymptomatic in the majority of cases. It belongs to the four clearly individualized forms of human osteopetrosis and has an autosomal dominant transmission. It induces generalized osteosclerosis, and most symptoms result from complications such as fractures following mild injury, compression of cranial nerves, especially the optic nerve, by stenosis of extracranial ostia, but also osteomyelitis of the lower maxilla. The treatment of Albers-Schönberg's disease is disappointing and only symptomatic, although the responsible genetic anomaly was recently identified. We report here the case of a 54-year-old woman, whose diagnosis of the disease has been known since adolescence, who presented with unilateral loss of vision and perimetric deficit due to papilla edema resulting from stenosis of the optic canal and benign intracranial hypertension.

Osteopetrosis--a challenge for the orthopaedic surgeon

Osteopetrosis (OP) is a rare heterogeneous group of inherited skeletal dysplasias characterised by osteoclast dysfunction, impaired bone resorption and poor bone remodelling. Three groups can be categorised on the basis of clinical findings. These include neurological symptoms, haematological abnormalities and renal tubular acidosis in the first group. Increased bone density, osteomyelitis and frequent fractures are the clinical findings in the second group, and the third group have normal life expectancy but may develop cranial nerve compression and osteomyelitis. Fractures in patients with OP are common and require appropriate pre-, peri- and postoperative management. The long bones are most frequently affected, fractures of the femoral neck and proximal (upper third) shaft being particularly common. This case report proposes possible operative fracture treatment in a patient with OP and highlights the potential perioperative pitfalls in this rare surgical population.

"Challenges in the management of fractures in osteopetrosis"! Review of literature and technical tips learned from long-term management of seven patients

Osteopetrosis is a metabolic disorder with diminished bone resorption due to osteoclastic abnormality. It causes hard and brittle marble bone which fractures easily. Most of these fractures can be treated conservatively. Operative intervention when needed presents with unique technical challenges. While osteopetrotic hard bone may be penetrated with a drill bit; high friction and prolonged drilling can make the drill bit blunt. The heat generated can cause bone necrosis and break the drill bit. Besides this, brittleness of bones can cause intra-operative fractures. Due to the difficulties during the operation, the operative time may be prolonged thereby increasing the risk of post-operative infection. There is also a risk of delay in consolidation and non-union owning to impaired bone remodelling. We present an account of seven patients treated for various fracture related problems occurring throughout their life due to this disease. Difficulties encountered during their treatment prompted us to present some general management principles.

Maxillomandibular osteomyelitis in osteopetrosis. Report of a case and review of the literature

INTRODUCTION

Osteopetrosis is a rare hereditary group of bony displasias. They range from a devastating metabolic disease (including severe malignant infantile osteopetrosis) to other conditions with a more benign phenotype (autosomal dominant osteopetrosis I and II).

CASE REPORT

Several case reports have been published of infectious complications affecting the mandible but maxillary affectation is quite rare. We present the case of a 23-year-old woman with a malignant recessive form of osteopetrosis complicated by repeated episodes of osteomyelitis (caused by actinomyces) of the mandible and maxilla.