Finally, a step forward in nomenclature of subchondral nonneoplastic bone lesions.

This paper is a commentary on the article entitled "Nomenclature of Subchondral Nonneoplastic Bone.Lesions1" by Gorbachova, Amber, Beckmann, Bennett, Chang, Davis, Gonzalez, Hansford, Howe, Lenchik, Winalski, and Bredella. The purpose of this commentary is to provide an orthopaedic perspective on the aforementioned article and critique their analysis and proposal regarding nomenclature of subchondral bone lesions. It provides an overview and a section by section evaluation of a well-designed and executed article.

Treatment of simple bone cysts of the humerus by intramedullary nailing and steroid injection.

BACKGROUND: Simple bone cysts (SBCs) are common benign lytic bone lesions in children. This study focused on exploring a clinical treatment method, minimally invasive intramedullary decompression and drainage with elastic stable intramedullary nailing (ESIN) combined with intralesional injections of steroids, and evaluated its effectiveness, complications and morbidity through functional and radiographic outcomes. METHODS: The postoperative recovery of 18 children who suffered from SBCs of humerus was evaluated (mean follow-up, 40 months) from January 2009 to December 2016. These patients (11 males, 7 females; 8 in the left, 10 in the right; mean age, 10.9 years old) were treated with minimally invasive intramedullary decompression and drainage with ESIN combined with intralesional injections of steroids. The diagnosis was based on not only pre-operative typical medical images (X-rays/CT/MRI) but also surgical findings and pathological diagnosis. Radiological and functional outcomes were evaluated according to Capanna and Musculoskeletal Tumor Society (MSTS) score. The interclass differences were analyzed by t-test. RESULTS: According to Capanna and MSTS criteria, after treatment, 14 patients made full recoveries which was presented by all the cysts filled with bone tissue, and 4 patients made partially recoveries, which were presented by cystic spaces partially filled with low density bone. All the cysts responded to treatment method, and there was no cyst recurrence. All except 2 patients had good functional results. One of the two patients had irritation of the end of the nail and one patient had a valgus deformity. CONCLUSIONS: Treatment for SBCs of humerus by minimally invasive intramedullary decompression and drainage with ESIN combined with intralesional injections of steroids is safe, effective and convenient. The clinical effect is satisfactory and worth popularizing.

Understanding Unicameral and Aneurysmal Bone Cysts.

Bone cysts in the pediatric population are often found incidentally on radiographs or after a cyst has created cortical weakness leading to a pathologic fracture. Most bone cysts are benign, are pain free, and resolve spontaneously. The most common bone cyst is unicameral 1-chamber bone cyst, also known as simple bone cyst. General practice pediatricians may be the first to encounter these lesions, and this article aims to help elucidate their incidence, etiology, clinical findings, radiologic findings, and modern treatment approaches. The other differential diagnoses that should be considered, specifically, aneurysmal bone cyst, are also explored. This summary is not all inclusive, and it is recommended that all patients be referred to a pediatric orthopedist.

Peri-prosthetic bone cysts after total ankle replacement. A systematic review and meta-analysis.

BACKGROUND: Periprosthetic cystic osteolysis is a well-known complication of total ankle replacement. Several theories have been proposed for its aetiology, based on individual biomechanical, radiological, histopathology and outcome studies. METHODS: Studies that met predefined inclusion/exclusion criteria were analysed to identify literature describing the presence of peri-prosthetic ankle cystic osteolysis. Quantitative data from the selected articles were combined and statistically tested in order to analyse possible relations between ankle peri-prosthetic bone cysts and specific implant characteristics. RESULTS: Twenty-one articles were elected, totalizing 2430 total ankle replacements, where 430 developed peri-prosthetic cystic osteolysis. A statistically significant association (P<.001) was found between the presence of bone cysts and non-anatomic implant configuration, hydroxyapatite-coating, mobile-bearing and non tibial-stemmed implants. No significant association existed between the type of constraining and the presence of cysts (P>.05). CONCLUSIONS: Non-anatomic, mobile-bearing, hydroxyapatite-coated and non tibial-stemmed total ankle replacements are positively associated with more periprosthetic bone cysts.

TREATMENT OF UNICAMERAL BONE CYSTS IN CHILDREN: A COMPARATIVE STUDY.

Unicameral bone cysts (UBC) are benign bone tumor-like lesions. Mostly they are located in the metaphyseal-diaphyseal region of long bones in children and adolescents. The etiology of UBC is still unclear. There is no consensus about the protocol of UBC treatment. The aim of this study was to evaluate the effectiveness of three different techniques for the treatment of UBC. This study included 129 pediatric patients with UBC treated at University Children's Hospital in Belgrade during the 8-year period. The mean follow up was 7.14 years. The following parameters were observed: gender, age, site, length of cyst, cyst index, cortical thickness, presentation of pathologic fracture, healing of cyst, treatment complications and length of hospitalization. These parameters were correlated to three treatment modalities, i.e. intracystic methylprednisolone acetate injection (group 1), curettage with bone grafting (group 2) and osteoinductive procedure using demineralized bone matrix (group 3). We found statistically significant differences in healing of the cysts and length of hospital treatment between groups 1 and 2, and between groups 2 and 3. In conclusion, complete healing of UBC can be achieved only using open surgery procedure. Intracystic methylprednisolone acetate instillation can be considered a good option for initial treatment of UBC.

Cystic bone tumors of the foot and ankle.

Bone tumors are relatively rare in the foot and ankle region. Many of them present as cystic lesions on plain films. Due to the relative rarity of these lesions and the complex anatomy of the foot and ankle region, identification of such lesions is often delayed or they get misdiagnosed and mismanaged. This review discusses the most common cystic tumors of the foot and ankle including their radiographic features and principles of management.

Epiphyseal pseudotumor of the tibia:an uncommon presentation of osteoarthritis.

Epiphyseal pseudotumor secondary to osteoarthritis are rare in patients under 50 years. We report here the case of a 48-year-old woman who complained of pain in the medial side of the left knee for three years. X-rays of the left knee showed a large lytic lesion containing multiple septae, with sclerotic margins at the upper end of the tibia, associated with knee osteoarthritis. An epiphyseal tumor of the left tibia was suspected. CT scan of the left knee concluded in a giant subchondral cyst secondary to osteoarthritis. Subchondral cysts or geodes are a common finding in patients with knee osteoarthritis. Nevertheless, some unusual aspects of the lesions may lead to diagnosis difficulties.

Simple and aneurysmal bone cyst: Aspects of jaw pseudocysts based on an experience of Brazilian pathology service during 53 years.

BACKGROUND: Jaw pseudocysts are benign osseous lesions of unclear etiology. Among these, the simple bone cyst (SBC) and aneurysmal bone cyst (ABC) are intriguing bone pathologies still rarely studied together. This retrospective study aimed to present the long-term case series of patients with jaw pseudocysts focusing on the clinical, radiographic, and transoperative aspects. MATERIAL AND METHODS: A retrospective case series of patients with SBC and ABC was performed. Clinical, radiographic, and transoperative aspects of both pseudocysts were reviewed from the histopathological archives of 20,469 cases between 1959-2012. All descriptive data were summarized. RESULTS: Of 354 (15.25%) bone pathologies, 54 cases of jaw pseudocysts were found, with 42 (11.86%) SBC and 12 (3.39%) ABC cases. For both lesions, most of the sample were young Caucasian women with an asymptomatic posterior mandible lesion with undetermined time of evolution and none trauma history. A unique radiolucent scalloped lesion presenting an empty cavity were also observed for both conditions. However, some atypical findings were found for SBC including: the expansion of bone cortical, tooth resorption, displacement of the mandibular canal, and recurrence. The absence of painful symptoms and the lack of classical blood-filled cavity were observed in some cases of ABC. CONCLUSIONS: The SBC and ABC are bone pathologies with few retrospective studies, no previous studies on the two conditions, varied nomenclature, and atypical aspects in some cases. Therefore, the knowledge of clinical, imaging, and transoperative features of such pseudocysts are clinically valuable as diagnosis hypothesis of radiolucent lesions of the jaws.

Traumatic bone cyst of an anterior mandible with previous symphyseal fracture in a pediatric patient: a rare finding and etiopathologic correlation.

Traumatic bone cysts (TBCs) are uncommon intraosseous lesions, classified as pseudocysts because they lack an epithelial membrane lining. The etiology of a pseudocyst has not been determined. Various hypotheses have been put forward to explain its pathogenesis, of which the traumatic-hemorrhagic theory is the most commonly accepted. Minor trauma, insufficient to cause fracture or iatrogenic injury, is commonly implicated as the stimulus initiating cyst formation. A TBC presenting after jaw fracture has been rarely reported in the literature. This article presents a case of a TBC of the anterior mandible in a child with a previous history of trauma and fracture of the symphysis. The article also reviews the literature to corroborate the possible role of major trauma in the pathogenesis of TBC.

[A solitary, defined radiolucency on a panoramic radiograph; cyst or no cyst?] / Een solitaire, begrensde radiolucentie op de panoramische röntgenopname; wel of geen cyste?

Sharply defined radiolucencies on a panoramic radiograph are often interpreted as cystic laesions. In some cases, however, it appears to be another condition, or an anatomical variation. In the present case, involving 2 healthy patients, 1 or more sharply defined lucencies were seen in the lateral parts of the mandible. After exploration, in both cases, an empty cavity was found without epithelial lining, which is pathognomonic for a simple bone cyst. Multiple occurrences are uncommon.

Florid osseous dysplasia associated with multiple simple bone cysts: a patient with 22 years of follow-up.

Florid osseous dysplasia (FOD) has been described as a condition that typically affects the jaws of middle-aged women of African descent and usually presents as multiple radiopaque masses distributed throughout the jaws. The diagnosis is generally based on clinical and radiographic presentation, often involving various regions of the jaws without evident bone expansion. This article describes the course of FOD in a 27-year-old African-American woman during 22 years of follow-up, emphasizing the dynamic radiographic characteristics of this entity and unusual co-occurrence with multiple simple bone cysts. These data reinforce the importance of long-term follow-up in patients diagnosed with FOD.

Cartilage Thickness and Cyst Volume Are Unchanged 10 Years After Periacetabular Osteotomy in Patients Without Hip Symptoms.

BACKGROUND: Periacetabular osteotomy (PAO) may affect cartilage thickness and cyst volume in patients with hip dysplasia. However, as no studies randomizing patients to either PAO or conservative treatment have been performed, to our knowledge, it is unknown if PAO directly affects the development or progression of osteoarthritis in patients with hip dysplasia. QUESTIONS/PURPOSES: We investigated (1) changes of cartilage thickness in the hip after PAO; (2) how many patients had subchondral bone cysts in the acetabulum or femoral head; (3) changes in cyst volume; and (4) patients' hip function and pain after PAO. PATIENTS AND METHODS: In this prospective study, 26 patients (22 women and four men) with hip dysplasia were enrolled with the goal of having MRI of the hip before undergoing PAO and again at 1, 2½, and 10 years after PAO. Of the 26 patients, 17 (65%) underwent complete followup 10 years after PAO, whereas nine could not be included. Of those nine, three had undergone THA, three had substantial hip symptoms, and three were lost to followup. Thickness of acetabular and femoral cartilage and volume of subchondral bone cysts were estimated in the remaining 17 patients. Ten years postoperatively, the patients' Hip disability and Osteoarthritis Outcome Scores (HOOS) were collected. RESULTS: Preoperatively, the mean thickness of the acetabular cartilage was 1.38±0.14 mm compared with 1.43±0.07 mm 10 years postoperatively (p=0.73). The mean thickness of the femoral cartilage preoperatively was 1.37±0.20 mm compared with 1.30±0.07 mm 10 years postoperatively (p=0.24). Seven patients had an increase in cyst volume, six had a decrease, and four had no cysts to start with and remained without cysts. Preoperatively, the median total cyst volume per patient was 6.0 cm3 (range, 1.6-188.3 cm3) compared with 2.9 cm3 (range, 0.7-8.2 cm3) (p=0.18) at 10 years followup. At 10 years, the mean subscores for the HOOS were: pain, 79±16; symptoms, 73±17; activities of daily living, 85±14; sport/recreation, 68±22; and quality of life, 61±19. CONCLUSIONS: Ten years after PAO, approximately 25% of the patients who have the procedure will have substantial hip pain and/or undergo hip arthroplasty. Of the patients who do not have substantial hip pain or an arthroplasty, cartilage thickness appears to be preserved. Future studies are needed to help us decide which patients are most likely to succeed with PAO at long-term followup. LEVEL OF EVIDENCE: Level II, therapeutic study.

Bilateral diaphyseal bone cysts of the tibia mimicking shin splints in a young professional athlete--a case report and depiction of a less-invasive surgical technique.

BACKGROUND: Medial tibial stress syndrome is one of the most common causes of exertional leg pain in runners whereas musculoskeletal tumors and tumor-like lesions are rare encounters in orthopedic sports medicine practice. Unicameral (simple) bone cyst is a well-known tumor-like lesions of the bone typically affecting children and adolescents. Bilateral occurrence is very rare though and has never been reported before in both tibiae. Failing to accurately diagnose a tumorous lesion can entail far-reaching consequences for both patients and physicians. CASE PRESENTATION: We report the case of large bilateral unicameral bone cysts of the diaphyseal tibiae mimicking medial tibial stress syndrome in a 17-year old professional athlete. This is the first report of symmetric tibial unicameral bone cysts in the literature. The patient complained about persisting shin splint-like symptoms over 5 months despite comprehensive conservative treatment before MRI revealed extensive osteolytic bone lesions in both diaphyseal tibiae. The patient-tailored, less-invasive surgical procedure, allowing the patient to return to his competitive sports level symptom-free 3 months after surgery and to eventually qualify for this years Biathlon Junior World Championships, is outlined briefly. Pathogenesis and various treatment options for this entity will be discussed. CONCLUSION: This report will help to raise awareness for musculoskeletal tumors as differential diagnosis for therapy-refractory symptoms in young athletes and encourage medical staff involved in sports medicine and athlete support to perform early high quality imaging and initiate sufficient surgical treatment in similar cases. Moreover, our less-invasive surgical procedure aiming for a fast return to sports might be an optimal compromise between traditional open curettage with low risk of recurrence and a soft tissue-saving and bone-sparing minimal-invasive technique.

Unicameral Bone Cyst in the Calcaneus of Mirror Image Twins.

Unicameral bone cysts (UBCs) are benign tumor-like lesions that commonly occur in the diaphyseal or metaphyseal region of the long bones within the first 2 decades of life. Until today, the pathogenesis of UBC has been unclear, but mechanisms such as vascular occlusion or a response to trauma have been supposed. During the past decade, in particular, the genetic aspects of the development of this rare lesion have been discussed. We present the first case of mirror image monozygotic twins with a mirror image UBC of the calcaneus. Our findings reinforce the importance of additional studies to understand the significance of cytogenetic factors in the etiology of UBC.

Unusual localizations of unicameral bone cysts and aneurysmal bone cysts: A retrospective review of 451 cases.

Unicameral bone cysts (UBC) and aneurysmal bone cysts (ABC) are benign cystic lesions of bone which are easily diagnosed. However, unusual locations may lead to a false diagnosis. Therefore the aim of this retrospective study was to determine the frequency of unusual localizations. The authors studied 451 cases with histopathologically confirmed diagnosis of UBC or ABC, seen between 1981 and 2012. In the UBC group (352 cases) humerus, femur and calcaneus were found to be the most common sites, while acetabulum, scapula, scaphoid, lunatum, metacarpals, metatarsals, toe phalanges and ulna each accounted for less than 1%. In the ABC group (99 cases) the most common sites of involvement were femur, humerus and tibia, while finger phalanges, ilium, acetabulum, pubis, calcaneus, cuboid, and toe phalanges each accounted for only 1%. The differential diagnosis of cystic bone lesions should include both UBC and ABC. Pain complaints plead for the latter, except in case of fracture.

Development and reliability of a multi-modality scoring system for evaluation of disease progression in pre-clinical models of osteoarthritis: celecoxib may possess disease-modifying properties.

OBJECTIVE: We sought to develop a comprehensive scoring system for evaluation of pre-clinical models of osteoarthritis (OA) progression, and use this to evaluate two different classes of drugs for management of OA. METHODS: Post-traumatic OA (PTOA) was surgically induced in skeletally mature rats. Rats were randomly divided in three groups receiving either glucosamine (high dose of 192 mg/kg) or celecoxib (clinical dose) or no treatment. Disease progression was monitored utilizing micro-magnetic resonance imaging (MRI), micro-computed tomography (CT) and histology. Pertinent features such as osteophytes, subchondral sclerosis, joint effusion, bone marrow lesion (BML), cysts, loose bodies and cartilage abnormalities were included in designing a sensitive multi-modality based scoring system, termed the rat arthritis knee scoring system (RAKSS). RESULTS: Overall, an inter-observer correlation coefficient (ICC) of greater than 0.750 was achieved for each scored feature. None of the treatments prevented cartilage loss, synovitis, joint effusion, or sclerosis. However, celecoxib significantly reduced osteophyte development compared to placebo. Although signs of inflammation such as synovitis and joint effusion were readily identified at 4 weeks post-operation, we did not detect any BML. CONCLUSION: We report the development of a sensitive and reliable multi-modality scoring system, the RAKSS, for evaluation of OA severity in pre-clinical animal models. Using this scoring system, we found that celecoxib prevented enlargement of osteophytes in this animal model of PTOA, and thus it may be useful in preventing OA progression. However, it did not show any chondroprotective effect using the recommended dose. In contrast, high dose glucosamine had no measurable effects.

Bone cysts in patients with afibrinogenaemia: a literature review and two new cases.

Afibrinogenaemia is an autosomal recessive disease with an estimated prevalence of approximately one in a million. The most common symptoms of afibrinogenaemia are umbilical cord bleeding, bleeding into skin, mouth, muscles, gastrointestinal and genitourinary tracts and the central nervous system. Other recognized complications include; haemarthroses, spontaneous splenic rupture, epistaxis, menorrhagia, recurrent abortion and venous and arterial thromboembolism. Bone cysts have also been described as a rare complication of afibrinogenaemia. The aim of this study was to conduct a systematic literature review, summarize the reported cases and to report two new cases. Three electronic databases were searched for relevant publications: PubMed, Medline and EMBASE. The following search criteria were used: '(bone cysts OR intraosseous haematoma OR intraosseous haemorrhage) AND (afibrinogenaemia OR fibrinogen deficiency)'. The reference lists of the selected papers were searched for more relevant literature. In total, eight patients had bone cysts as complication of afibrinogenaemia and six of them suffered from pain in their extremities. Bone cysts were primarily located in the vicinity of the cortex or trabeculae in the diaphysis of the long bones, especially in the femora, tibiae and humeri. Some were regressive, probably due to reactive bone remodelling. A number of cysts were filled with serosanguinous fluid. It might be useful to check for bone cysts when patients with congenital afibrinogenaemia complain of 'rheumatic' pains in their extremities. Whole body magnetic resonance imaging is the diagnostic imaging technique of choice. Recurrent episodes of pain, but not radiological deterioration, appear to benefit from prophylactic therapy with fibrinogen concentrate.

Benign bone tumors.

Benign bone lesions are a broad category that demonstrates a spectrum of activities from latent to aggressive. Differentiating the various tumors is important in order to properly determine necessary intervention. This chapter focuses on the presentation, imaging, diagnostic features, and treatment of the most common benign bone tumors in order to help guide diagnosis and management.

Imaging evaluation of musculoskeletal tumors.

In this chapter, we review different imaging modalities, including radiography, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and nuclear medicine scintigraphy, and their application to musculoskeletal neoplasm. Advantages and limitations of each modality are reviewed, and suggestions for imaging approach are provided.