Update on aneurysmal bone cyst: pathophysiology, histology, imaging and treatment.

Aneurysmal bone cyst (ABC) is a benign but locally aggressive lesion that predominantly affects children and young adults. ABC, which accounts for approximately 70% of the cases, is now recognized to be a true neoplasm, whereas ABC-like changes associated to other bone neoplasms (also referred in the literature as secondary ABC) accounts for the remaining 30%. The solid variant of ABC is also considered a true neoplasm but is rare. ABC can involve any bone in the body, and although it has a metaphyseal preference, it can involve any part of a bone and soft tissues. As with any bone tumor, the initial evaluation of ABCs should be done with radiographs followed by magnetic resonance imaging or less frequently computed tomography for further characterization. The imaging appearance of ABC is variable; however, a lytic and expansile lesion with fluid-fluid levels is the most common presentation. The main differential diagnosis of an ABC in the pediatric population is unicameral bone cyst (UBC) and telangiectatic osteosarcoma, therefore a biopsy is recommended before treatment. The therapeutic options of ABC range from curettage with or without adjuncts such as phenol, liquid nitrogen, argon laser and bone grafting or bone substitutes to more recently employed alternatives such as image-guided sclerotherapy with various sclerosing agents and monoclonal antibodies (e.g., Denosumab).

Outcomes of Surgical Management of Intraosseous Ganglia of the Carpal Bones: A Case Series.

BACKGROUND: Intraosseous ganglia of the carpal bones are uncommon with sparse publications to guide treatment. The purpose of this study was to review a single-institution experience to determine the outcomes of patients with surgically treated intraosseous carpal ganglia. METHODS: Skeletally mature patients with intraosseous carpal ganglia between 1995 and 2016 treated operatively were identified. Demographic information, clinical data, and radiographic studies were evaluated. RESULTS: Thirty-three ganglia in 31 patients were identified. Intraosseous ganglia were located in the lunate (23), scaphoid (9), and trapezoid (1). Patients who presented with pathologic fracture or collapse had larger intraosseus ganglia than those presenting with pain alone. Surgery significantly improved pain. Patients treated with debridement with autograft bone graft had a higher consolidation rate compared with allograft bone but no difference in pain. CONCLUSIONS: Patients with large or symptomatic lesions can be treated successfully with curettage and debridement, which leads to relief of pain. The use of bone grafting remains controversial.

Evaluation of different treatment modalities for fractured and non-fractured simple bone cyst: A single-center review of 68 patients.

ABSTRACT: Simple bone cysts (SBCs) occur most frequently in the proximal aspect of the humerus and femur in growing age and are associated with intercurrent pathological fractures in up to 87%. Therapeutic management of SBCs remains controversial. The aim of this study was to examine the outcome of conservative and various surgical treatment modalities considering the specific anatomic location and integrity of the SBC.In this retrospective study, we analyzed 68 cases of SBCs who underwent a conservative or surgical treatment between 2009 and 2020 with a mean follow-up of 30.1 months. The epidemiological characteristics, complications, clinical, and radiographic outcome after conservative or surgical treatment were assessed.The study includes 50 male (73.5%) and 18 female (26.5%) patients with a mean age of 9.1 years. The most common locations were the proximal humerus (69.2%, n = 47) and femur (16.2%, n = 11). In 43 cases (63.2%; upper limb n = 40, lower limb n = 3) a pathological fracture occurred. Fifty patients (73.5%; upper limb n = 40, lower limb n = 10) underwent a conservative treatment. In 11 cases (16.2.1%; upper limb n = 4, lower limb n = 7) an intralesional curettage and defect reconstruction with bone substitute without stabilization were performed. Five patients (7.3%; upper limb n = 4, lower limb n = 1) received an osteosynthesis, in two cases (2.9%; upper limb 1; lower limb 1) combined with an intralesional curettage and defect reconstruction with bone substitute. All 32 pathological fractures treated conservatively (upper limb n = 31, lower limb n = 1) healed within 6 weeks; 17/43 patients (39.5%) suffered at least one second fracture. After intralesional curettage and defect reconstruction with bone substitute local recurrence was observed in 5/13 cases (38.5%). Spontaneous consolidation, at least partially, was observed in three cases (4.4%) following conservative treatment after fracture. No relevant secondary angular or torsional deformity was observed after treatment.The majority of SBCs can be treated conservatively, especially in the upper extremity. However, if a fracture is completely dislocated, joint affecting, unstable or open, surgical treatment is necessary. Load-dependent pain or the inability to mobilize timely after fracture can necessitate surgical treatment in SBCs affecting the lower extremity. Spontaneous resolution, especially after fracture, can be seen in rare cases.

Calcaneal Bone Tumors.

Bone tumors of the foot are an uncommon finding. Most tumors are found incidentally on imaging and are benign. Care must be taken although due to the aggressive nature of malignant bone tumors that can occur in the calcaneus. Malignant lesions will more commonly present with symptoms of pain and swelling. Often misdiagnosed as soft tissue injuries, it is critical to be able to diagnose and treat these lesions early. Imaging plays an important role with plain films and advanced imaging. Surgical treatments can range from curettage with grafting to amputation for more aggressive lesions.

SIRT1+ Adipose Derived Mesenchymal Stromal Stem Cells (ASCs) Suspended in Alginate Hydrogel for the Treatment of Subchondral Bone Cyst in Medial Femoral Condyle in the Horse. Clinical Report.

Stem cell based therapy are now commonly applied in human and veterinary medical practice especially in orthopaedics. Mesenchymal stromal stem cells isolated from adipose tissue (ASC) are first choice option due to relatively non-invasive and safe procedure of tissue harvesting. However, ASC therapeutic potential strongly rely on patients general health condition, age and life-style. For that reason, to enhance therapeutic potential of cells, they are modified in vitro using different approaches. Previous studies have shown, that ASC treated with resveratrol, herein called SIRT+, are characterised by decreased senescence, increased proliferation rate and improved clinical outcome in autologous therapies. Herein, SIRT + cells in alginate hydrogel were applied to 5 years old warm breed mare was clinically evaluated due to the left hind lameness due to subchondral bone cyst. The therapeutic effect was assessed by the analysis of lameness score and radiological evaluation. This case report demonstrates the therapeutic potential of SIRT + cells in the treatment of orthopaedics disorders in horses as complete bone remodelling occurred after therapy and horse came back to training.

Treatment of simple bone cyst with bone marrow concentrate and equine-derived demineralized bone matrix injection versus methylprednisolone acetate injections: A retrospective comparative study.

OBJECTIVE: The aim of this study was to compare the outcome of intra-lesional autologous bone marrow concentrate (BMC) and equine derived demineralized bone matrix (EDDBM) injections with methylprednisolone acetate injections in patients with simple bone cyst. METHODS: Clinical records and radiographs of 53 consecutive patients (37 females,and 16 males; mean age: 10.6±1.53 years) treated between 2006 and 2016 were retrospectively reviewed. Healing was assessed by an independent radiologist according to Neer scoring system. Functional outcome was assessed with the Activity Scale for Kids (ASK). Thirty-four cysts were in the humerus, 13 in the femur and 6 in other locations. Twenty-nine patients were included in Steroid Group and treated with 3 cycles of injections of methylprednisolone acetate, while 24 patients were treated with injection of autologous bone marrow concentrate and equine derived demineralized bone matrix (BMC+ EDDBM Group). The two groups were homogenous for the mean age, sex distribution, cysts location and their clinical presentation. RESULTS: At a minimum follow-up of 24 months, success rate (Neer/Cole score 3 and 4) was higher in EDDBM+BMC group (83.3% vs 58.6%; p=0.047). Female patients had higher healing rates in both groups (p=0.002). No association was found between healing and age (p=0.839), cyst activity (p=0.599), cyst localization (p=0.099) and clinical presentation (p=0.207). BMC+EDDBM group showed higher ASK score (p=0.0007). CONCLUSION: Treatment with BMC+EDDBM injections may provide better results with a single procedure than 3 methylprednisolone acetate injections and represent an interesting alternative for the treatment of unicameral bone cysts. LEVEL OF EVIDENCE: Level III, Therapeutic Study.

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.

Current Trends and Variations in the Treatment of Unicameral Bone Cysts of the Humerus: A Survey of EPOS and POSNA Members.

BACKGROUND: A variety of treatment methods have so far been described for unicameral bone cysts (UBC). However, to the best of our knowledge, no particular consensus has yet been reached on when to operatively treat a patient with a humeral UBC. Therefore, members of the European Pediatric Orthopedic Society (EPOS) and Pediatric Orthopedic Society of North America (POSNA) were surveyed to characterize current treatment preferences. METHODS: An online electronic questionnaire was sent out to all registered EPOS and POSNA members. The survey comprised 45 questions related to the diagnosis, treatment, and follow-up characteristics of patients with UBCs of the humerus. Particular questions related to the nonoperative or surgical treatment of pathologic proximal humerus and humeral shaft fractures were also included. RESULTS: In total, 444 participants (132 EPOS and 292 POSNA members) responded, of whom 400 were actively involved in UBC treatment. The preferred diagnostic modalities to confirm the diagnosis of a UBC in the humerus were radiographs (88%), MRI in cases of questionable diagnosis (58%) or CT scan (8%). For painless UBCs 67% prefer no treatment at all except when the fracture risk is deemed high (then 53% recommend surgery); 71% of respondents would treat painful UBCs with surgery. Most common surgical techniques comprise curettage (45%), artificial bone substitutes (37%), corticosteroid injection (29%), or intramedullary stabilization (eg, rodding; 24%).Fractured, nondisplaced and mildly displaced proximal humerus UBCs and mildly displaced pathologic humerus shaft fractures are all preferably treated nonoperatively (94%, 91%, 83%, respectively). Severely displaced pathologic proximal humerus fractures are treated less often conservatively (36%) than surgically (40%), and severely displaced humerus shaft fractures are preferably treated surgically (63%) by intramedullary stabilization (60%). CONCLUSIONS: There is great variation among EPOS and POSNA members with regards to the diagnosis and treatment of UBCs in the humerus. Although some consensus on general treatment principles is seen, specific surgical treatment indications vary.Prospective randomized-controlled studies are needed to evaluate the outcomes of the different surgical approaches compared with nonoperative strategies. LEVEL OF EVIDENCE: Level V-expert opinion.

Allergic reaction to platelet-rich plasma (PRP): Case report.

RATIONALE: In the recent years, growing interest is focused on the use of platelet-rich plasma (PRP) in wound healing and tissue regeneration. There are a number of papers regarding the usefulness of PRP in the healing of ulcerations, skin injures, bone loss or distraction osteogenesis. Most authors emphasize the safety of PRP usage due to its authogenic nature. PATIENT CONCERNS: We present a case of a 14 -year-old boy admitted to our department due to simple bone cyst of the distal tibia, qualified for injection of PRP into the cyst. PRP was separated with the use of Magellan Autologous Platelet Separator System (Arteriocyte Medical Systems Hopkington, MA) according to the manufacturers' manual. Immediately after separation during short-term IV anaesthesia, 3 mL of PRP was installed to the bone cyst under image intensifier control. DIAGNOSES: Within the first 24 hours after exposure to PRP, the skin rash appeared. Physical examination revealed the small red papular, regionally purpuric eruptions, mainly concentrated on the upper extremities and on more warmed regions of skin, in association with pharyngitis, tonsillar enlargement, mucopurulent discharge in the posterior pharynx and swelling of the eyelids. INTERVENTIONS: As the patient received calcium citrate with the PRP injection additional calcium citrate test were performed. Skin prick testing (negative) was and an intradermal test was positive (10×13 mm). Treatment included Claritine (Loratidinum) and Clemastin (Clemastinum)-both antihistaminic drugs. OUTCOMES: All symptoms withdrew and the patient was released home after 4 days. The patient is in 6 years follow-up without any symptoms of allergic disease. LESSONS: Our case shows that safety of use of PRP is not absolutely sure. The pure autologous tissue is safe, but preparation for its use can substantially decrease this safety. In our patient, only limited skin reaction to calcium citrate was observed, but general reaction leading to anaphylactic shock cannot be excluded. In order to reduce the risk of side effects skin test should be performed but as there were no records of allergic diseases on family and patients medical history this should apply to all patients.

Bone Marrow Aspirate in Cystic Maxillofacial Bony Defects.

Autogenous or alloplastic bone grafts are routinely applied for reconstruction of cystic bone defects. Addition of mesenchymal bone marrow stem cell in osteoconductive alloplastic bone makes it osteoinductive and osteogenic. The purpose of this study was to evaluate the role of bone marrow aspirate in regenerating new bone with hydroxyapatite collagen scaffold in patients with large cystic maxillofacial defects. This prospective randomized study had random allocation of 15 patients with large cystic maxillofacial bony defects in each of the 2 groups. Group I patients received hydroxyapatite granules and bone marrow aspirate in collagen sponge and group II received hydroxyapatite granules only. Clinical and radiologic assessment showed the time taken in bone healing. In group I, the bone defect volume reduction was statistically significant at 3 and 6 months, the postoperative pain and swelling was less, and there was no tooth mobility at 3 months. The authors concluded that use of hydroxyapatite granules with bone marrow aspirate in collagen sponge in maxillofacial bone defects provided early bone regeneration, and faster wound healing. However, to arrive at a definitive conclusion a long-term study with a larger sample size is required.

Humeral Simple Bone Cysts: Observational Versus Interventional Management.

AIMS: Our study aims to review the outcomes of conservative and interventional management of simple bone cysts (SBC) in the humerus. METHODS: We retrospectively reviewed our center's prospectively collected database. All patients with a diagnosis of a humeral SBC and a minimum of 1-year follow-up or complete healing and discharge within the first year were included. Cyst radiographic measurements were collected for all patients with available radiographs. A successful outcome included fully or partially healed cysts with persistent and recurrent cysts marked as unsuccessful. RESULTS: In total, 91 patients were included in the study. Within the observational group, 44 patients (95.7%) achieved a successful outcome versus 38 patients (84.4%) in the interventional group. The 15/61 (25%) patients who were treated with observation at presentation required intervention at a later stage. The 9/30 (30%) of patients who had intervention at presentation required further additional intervention. Seven patients (11%) presenting with a fracture through a SBC went on to complete consolidation of the cystic lesion following the injury at a mean of 92.9 days (maximum, 176 d). CONCLUSIONS: We observed similar outcomes with conservative and interventional management in our retrospective series. We recommend observational management when a radiologic diagnosis is possible with intervention reserved for cases of diagnostic uncertainty and intrusive symptoms. LEVEL OF EVIDENCE: Level III-a retrospective case comparison study.

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.

Scaphoid Cysts: Literature Review of Etiology, Treatment, and Prognosis.

Background: Cystic lesions of the carpal bones are rare entities that are infrequently reported in the literature. Scaphoid intraosseous cystic lesions represent a rare subset of carpal bone cysts. This review aims to summarize the available evidence on the evaluation and treatment of scaphoid cystic lesions to help guide clinical management. Methods: Systematic electronic searches were performed using PubMed, Ovid, and Embase databases. Studies included were graded for their risk of bias. Pooled descriptive statistics were performed on incidence, etiology, physical exam findings, treatment, and follow-up. Results: A total of 38 patients representing 41 scaphoid cystic lesions were pooled from 27 articles. Patients presented with wrist pain without fracture (n = 27), pathological fracture (n = 9), swelling only (n = 1), or were asymptomatic (n = 4). Cystic lesions of the scaphoid were initially revealed on imaging with radiographs alone (n = 22), radiographs in combination with computed tomography (CT) (n = 10) or magnetic resonance imaging (n = 6), CT alone (n = 1), or using all 3 modalities (n = 2). Intraosseous ganglia were identified most frequently (n = 31), followed by "bone cyst-like pathological change" (n = 3), unicameral bone cysts (n = 2), aneurysmal bone cysts (n = 2), primary hydatid cysts (n = 2), and cystic like changes post fall (n = 1). Treatment modalities included curettage and bone graft (n = 39) or below-elbow cast (n = 2). On follow-up (average of 21.3 months; n = 40), all patients improved clinically after treatment and were found to have full wrist range of motion without pain (n = 31), slightly reduced grip strength (n = 3), limited range of motion (n = 2), or persistent mild discomfort (n = 2). Conclusions: Scaphoid cystic lesions are most commonly intraosseous ganglia, but can include other etiologies as well. The main presenting symptom is radial wrist pain that usually resolves after treatment. The presence of intracarpal cystic lesions should be considered in the differential diagnosis of wrist pain.

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.

Subchondral bone cyst surgical treatment using the application of stem progenitor cells combined with alginate hydrogel in small joints in horses.

One of the most common reasons for horse lameness is subchondral bone cysts (SBCs), which are especially evident in young horse athletes. It is believed that SBC development is strongly associated with an individual's bone growth and/or bone microstructure impairment. Current methods of SBC treatment include pharmacological treatment or surgical procedures which may allow the bone within the cyst to rebuild and be restored to properly developed bone tissue. Thus, we propose filling the SBCs with a 3D complex of alginate hydrogel and autologous adipose derived mesenchymal stem cells (ASCs). We have observed at the in vitro level, that this hydrogel complex induces osteogenic and chondrogenic differentiation potential through the upregulation of bone morphogenetic protein, osteopontin, collagen type I and aggrecan mRNA levels. Moreover, we detected the creation of a 3D extracellular matrix (EM). To investigate the complex in vivo, we chose 8 horses of varying age suffering from SBC, which resulted in lameness, to undergo experimental surgery. We documented the horses' clinical appearance, lameness and radiographic appearance, to determine that there was clinical improvement in 87.75% of the patients (n=7, out of 8 horses) 6 months postoperatively and 100% (n=8, out of 8 horses) a year after surgery. These results are promising for the potential of this procedure to become the standard in SBC treatment.

Conservative treatment of a pathologic fracture of the scaphoid bone in a child: A case report.

RATIONALE: Tumors of the scaphoid are rare, and some can cause pathological fractures. No cases of pathological fractures of the scaphoid have been reported in children. The most common treatment for pathologic fractures of the scaphoid bone associated with a benign lesion in adults is surgical, with intralesional curettage associated with autologous bone grafting and internal fixation. PATIENT CONCERNS: A 10-year-old boy presented with wrist pain after falling from his height. DIAGNOSES: X-ray, CT-scan and MRI showed a pathological undisplaced fracture of the scaphoid on a benign lytic lesion. INTERVENTIONS: The arm was immobilized in a below-elbow cast. OUTCOMES: The fracture healed within 4 months of immobilization. 3 years after the fracture, the functional status was normal, and the lytic lesion could not be seen on radiographs. LESSONS: Retrospectively, the most probable etiology was a ganglion cyst. Our case suggests that some pathological fractures of the scaphoid may not need surgery, especially not in children.

[Bone cysts-differential diagnosis and therapeutic approach]. / Knochenzysten ­ Differenzialdiagnose und therapeutisches Vorgehen.

The differential diagnosis of cystic lesions of the skeleton is multifarious. Besides patient age, the localization and radiologic morphology provide important information for a closer differentiation. Juvenile and aneurysmal bone cysts represent two frequent entities in growing patients. The fluid content of the cysts helps in distinguishing between juvenile and aneurysmal bone cysts. Whereas juvenile bone cysts contain clear fluid, the content of aneurysmal bone cysts consists of blood combined with solid tissue. With respect to progression, aneurysmal bone cysts show a higher activity than solitary bone cysts. The treatment of juvenile bone cysts usually consists of curettage including filling with bone replacement material. For aneurysmal bone cysts the additional use of adjuvants is recommended. Bone cement is preferably used for filling. It shows favorable properties for prophylaxis of recurrence and facilitates the recognition of relapses. Both juvenile and aneurysmal bone cysts often show recurrences.

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.

Intraosseous ganglion cyst of the distal tibia: a rare entity in a rarer location.

Intraosseous ganglion cysts are rare entities, even rarer in the subchondral region of the distal tibia. A 20-year-old male presented to us with complaints of pain and limp in the right ankle joint, which was diagnosed as an intraosseous ganglion cyst of the right distal tibia and was successfully treated with curettage and bone cement with no recurrence seen even after a year.