» Unicameral bone cysts (UBCs) can increase the risk of pathologic fractures of both long and short bones. Although multiple treatments exist, data are conflicting regarding optimal management.
» We sought to analyze treatment strategies for UBCs and their rates of successful treatment.
» Success rates were analyzed according to treatment modality, with emphasis on filling techniques and/or decompression associated with curettage, and injection compounds.
» Curettage with bone substitute and cyst decompression was identified as a highly successful technique for UBC treatment.
» Decompressing the cyst wall after injection, regardless of the specific compound used, had a greater potential to enhance healing rates.
» The management decision should be individually guided within the patient\'s context.

BACKGROUND: when faced with a chronic digital injury, the differential diagnosis between osteomyelitis or primary tumor is raised. Coexistence between osteomyelitis and epidermoid bone cyst is not uncommon.
METHODS: in this article, we describe two cases of epidermoid cysts in distal phalanx of the hand associated with osteomyelitis and a review of the literature is presented.
RESULTS: both osteomyelitis and epidermoid bone cyst have been related to the presence of previous trauma at the site of the lesion, nail alterations and chronic phlogotic signs, so it is important to reach a diagnosis of certainty through an anatomopathological study and to perform a good surgical debridement to ensure the healing of both entities.
CONCLUSIONS: surgical debridement associated with curettage and filling of the bone defect with bone substitute with antibiotic is a good therapeutic option in the treatment of these lesions.
UNASSIGNED: ante una herida crónica a nivel digital se plantea el diagnóstico diferencial entre osteomielitis o tumor primario. No es infrecuente la coexistencia entre osteomielitis y quiste óseo epidermoide.
UNASSIGNED: en este artículo describimos dos casos de quistes epidermoides en falange distal de la mano asociados a osteomielitis y se presenta una revisión de la literatura.
RESULTS: tanto la osteomielitis como el quiste óseo epidermoide se han relacionado con la presencia de un traumatismo previo en el sitio de la lesión, alteraciones ungueales y signos flogóticos crónicos, por lo que es importante llegar a un diagnóstico certero mediante un estudio anatomopatológico y realizar un buen desbridamiento quirúrgico que asegure la curación de ambas entidades.
CONCLUSIONS: el desbridamiento quirúrgico asociado a curetaje y relleno del defecto óseo con sustituto óseo por medio de antibiótico es una buena opción terapéutica en el tratamiento de estas lesiones.

Cysts of the bone are a common pathology that, although benign, are frequently treated because of their tendency to compromise the integrity of affected bone. Two common entities are unicameral bone cysts and aneurysmal bone cysts. Although these are two distinct pathologies, they are treated similarly and thus will be discussed in tandem. The optimal treatment of calcaneal bone cysts in pediatric patients has long been debated among orthopaedic surgeons because of the relatively small number of cases and varied results within the literature. Currently, there are three lines of thought regarding treatment: observation, injection, and surgical intervention. When considering which course of treatment is best for an individual patient, the surgeon must consider the fracture risk without treatment, the risk of complications with treatment, and the recurrence rate with each treatment approach. There are limited data on pediatric calcaneal cysts specifically. Still, there are much data concerning simple bone cysts of long bones in the pediatric population and calcaneal cysts in the adult population. Because of the lack of literature on the subject, there is a need for a review of the available literature and a consensus on the approach to treating calcaneal cysts in the pediatric population.

OBJECTIVE: Numerous approaches to the management of juvenile and aneurysmal bone cysts (ABC) are described in the specialist literature together with discussion of the associated healing and recurrence rates. Since there is currently no evidence-based treatment standard for these conditions, the aim of this systematic literature review with meta-analysis was to examine the different management approaches, evaluate the corresponding clinical outcomes and, as appropriate, to formulate a valid treatment recommendation.
METHODS: A systematic search on OVID Medline® based on a pre-existing search strategy returned 1333 publications. Having defined inclusion and exclusion criteria and analysis of the relevant full texts, 167 publications were included in the descriptive analysis and 163 in the meta-analysis. For this purpose, different subgroups were created, based on the type of cyst and the therapeutic procedure. Those subgroups were then analysed in relation to their healing rates, the number of recurrences and complication rates.
RESULTS: For aneurysmal bone cysts, both surgical removal and Doxycycline injection lead to excellent outcomes (98% healing) and low recurrence rates (6% and 11% resp.). Curettage (91% healing), including its combination with autologous cancellous bone graft (96% healing), showed very good healing rates but higher recurrence rates (22% and 15%, resp.), which were however improved by preoperative selective arterial embolization. A critical view must be taken of radiotherapy (90% healing) and the injection of alcohol (92% healing) because of their high complication rates (0.43/cyst and 0.42/cyst, resp.). In the management of juvenile bone cysts, surgical interventions like curettage and cancellous bone graft (87% healing) are far superior to non-surgical approaches (51% healing), furthermore, the application of autologous cancellous bone graft reduced the recurrence rate (3% recurrence) compared to curettage alone (20% recurrence). In subgroup analysis, treatment by ESIN was found to produce excellent outcomes (100% healing), though the patient collectives were small.
CONCLUSIONS: Surgical procedures to treat aneurysmal bone cysts appear to be the method of choice whereby Doxycycline injection may be an alternative. A surgical approach should be preferred in the treatment of juvenile bone cysts.

BACKGROUND: Solitary bone cysts in the calcaneus (calcaneal bone cysts) are often asymptomatic. Pathological fractures are rare, and few reports are available concerning its risk assessment. Therefore, the indication for operative interventions remains debatable, and further discussion on the treatment of symptomatic cysts and pathological fractures in calcaneal bone cysts is necessary.
METHODS: Clinical data of 21 patients with calcaneal bone cysts (16 men and five women) was retrospectively reviewed. The average age was 13.3 (range, 7-23) years. Clinical data, such as concerning symptoms, radiological findings, pathological findings and outcomes, were investigated, and the pathogenesis of symptomatic cysts was studied.
RESULTS: Thirteen cysts were symptomatic, and eight were incidentally discovered. Computed tomography revealed no fracture in 12 cases, microfracture in eight and complete fracture in one. The areas under the curves of the receiver operating characteristic curves calculated to establish an association between cyst size and symptoms and cyst size and pathological fractures (microfracture and complete fracture) were 0.78 and 0.71, respectively. Symptomatic cysts and pathological fractures were associated with the cyst ratio (cyst size/calcaneus ≥ 0.20). On magnetic resonance imaging (MRI), fluid levels were observed in 11 of 21 (52%) patients. At the time of surgery, blood from the haemorrhage was aspirated from 15 of 21 (71%) cysts.
CONCLUSIONS: Orthopaedic surgeons should be aware that the cyst ratio is associated with clinical symptoms and pathological fractures. MRI and gross findings revealed haemorrhage in the cystic fluid. In calcaneal bone cysts, repeated microfractures and spontaneous healing might occur.

UNASSIGNED: 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.

BACKGROUND This article presents a rare case of 2 separate intraosseous ganglion cysts of the talus in a 51-year-old man, treated with a unique technique of precise lesion targeting to avoid extensive bone loss and minimize articular chondral injury of the talus. CASE REPORT Two separate intraosseous ganglion cysts of the talus were diagnosed in a 51-year-old man with chronic ankle pain. A single straight-line incision with an entry point through the talonavicular joint was created to spare the precarious blood supply of the talus network. The 2 distinct subchondral lesions were approached under fluoroscopic control for curettage and autologous bone grafting using the anterior cruciate ligament tibial guide in a pair-of-compasses fashion. In almost 5 years of follow-up the patient has been asymptomatic. Magnetic resonance imaging has revealed no signs of degenerative changes in the ankle or the talonavicular joint, and the intraosseous edema has almost disappeared. CONCLUSIONS To the best of our knowledge, this case is the first report of 2 distinct intraosseous ganglion cysts of the talus. We recommend the precise targeting technique used in our case for treating intraosseous talar lesions with intact articular cartilage.

BACKGROUND: Intraosseous lipomatosis is a rare and uncommon entity with only a few cases reported in the literature.
METHODS: We report a severe case where post-traumatic radiographs showed multiple cystic osseous lesions and a pathological fracture. The findings were expanded with whole-body magnetic resonance imaging (MRI), which showed multiple osseous lesions with typical MRI characteristics of intraosseous lipomas.
CONCLUSIONS: Our case, together with very few other cases described in the literature, emphasizes that multiple intraosseous lipomatosis is an important differential diagnosis for multiple radiolucent lesions on plain radiographs. Multiple intraosseous lipomatosis can lead to pathological fractures and severe impairment of life quality. The presence of well-defined, osteolytic lesions in the bone calls for an MRI or computed tomography scan.

OBJECTIVE: To systematically review the literature to determine recurrence rates of percutaneous treatments for primary aneurysmal bone cysts (ABC).
METHODS: Search strategies were performed in the following databases: PubMed, SCIELO, LILACS and BVS, using terms in English, Spanish and Portuguese (PROSPERO Registration Number: CRD42020170340). Longitudinal studies, either observational or clinical trials, with at least five patients and with a mean of 18 months of follow-up were included. Studies had to use any type of percutaneous treatments and report the recurrence rates of primary ABC treatment. Studies selection, data extraction and risk of bias assessment were performed independently by two researchers. A global meta-analysis was carried out to assess the proportion of recurrence. Studies were categorized into two subgroups: selective arterial embolization and sclerotherapy.
RESULTS: Thirteen studies were included in the present study. The average success rate of percutaneous treatments for ABC was 91.11%, with a total of 37 lesions recurrences in the 416 patients. The sex ratio was 1:1. The subgroup of sclerotherapies presented a lower proportion of recurrence. The proportion of recurrence in the subgroup of selective arterial embolization was 19% (95%IC 12.11-27.54) and that of sclerotherapies was 6% (95%IC 3.65-9.19).
CONCLUSIONS: Both percutaneous treatments for ABC are effective, showing a lower rate of recurrence. Sclerotherapy treatments seem to be promising, but further clinical trials must be conducted with a longer follow-up.

Background: Calcaneal bone cysts rarely occur and most of them are known to be benign. Among them, simple bone cysts (SBCs) third most commonly occur in the calcaneus and of the many surgical treatment options, endoscopic curettage is recently gaining popularity among surgeons due to its advantages of minimal invasiveness and optimal visualization. As for portal placement for endoscopy, two lateral portals are considered a standard technique, but no rationale has been established for SBCs with abnormal geometry. This case report suggests an SBC with secondary aneurysmal change located outside the Ward\'s triangle, as well as an appropriate endoscopic approach. Case Presentation: An 18-year-old male high school student presented with a main complaint of pain at the hind foot level for the past one year, without significant improvement from conservative treatment. An endoscopic curettage through the lesion specific two posterior portals and bone graft using allogeneic cancellous bone were performed. SBC with a secondary aneurysmal bone cyst was diagnosed on pathology. At a one-year follow-up, the patient was painless and had returned to his regular activities. Physical and radiographic examinations revealed that the lesion was completely healed without any evidence of recurrence. Conclusion: For calcaneal bone cysts located at the posterior aspect of the calcaneus, eccentrically medial and abnormally long anterior-posteriorly, we suggest an endoscopic procedure using lesion specific portals such as two posterior portals.