Modern treatment of unicameral and aneurysmatic bone cysts.

The best treatment of unicameral bone cyst and aneurismatic bone cyst (ABC) is debated in the literature. For simple bone cysts, multiple treatments were proposed from observation only to open curettage. The historical treatment with intraosseous injection of methylprednisolone acetate into the bone cysts nowadays is reduced due to the morbidity of multiple injections and the risk of multiple pathologic fractures until the healing. Different types of treatments for ABC are reported, including surgery, percutaneous treatments, and medical treatments; however, there is currently no consensus on the best approach. The association of curettage, bone graft, and elastic stable intramedullary nail (ESIN) had a success rate of over 85%. Decompressing the cyst wall is more critical for increasing the healing rate than the type of graft used to fill the cavity. In ABC, sclerotherapy offers the advantages of lower invasiveness and morbidity, associated with better functional scores and faster return to full weight-bearing. Moreover, they can be used in challenging locations. Selective arterial embolization is a complex procedure and often requires association with other treatments. Further studies are needed to confirm the effectiveness of denosumab and its side effects on skeletally immature patients. Curettage with adjuvants and autogenous bone grafting still shows promising results and can be used in larger, aggressive defects or superficial lesions. For simple bone cysts, the combination of curettage, bone graft, and ESIN showed the best results. Sclerotherapy for ABC also shows promising results.

Pediatric Hip Pain with Bone Lesion, Sepsis, and Occam's Razor = Brodie's Abscess Case Report.

Introduction: Brodie's abscess is one type of subacute osteomyelitis that can be difficult to diagnose because characteristic signs and symptoms can be subtle and non-specific. Up to 90% of Brodie's abscess cases are initially misdiagnosed, with a mean delay of 3 months to the correct diagnosis, with 50% of them misdiagnosed as tumors. Other conditions can also present quite similarly. Case Report: A 7-year-old male presented with complaints of hip pain and inability to bear weight. X-rays revealed Brodie's abscess in the proximal femur which was initially misdiagnosed as toxic synovitis with an incidental unicameral bone cyst (UBC). Conclusion: Brodie's abscess can be a diagnosis that is easily missed and should be included in the differential diagnosis when a child presents with a limp, inability to bear weight, or when a cortical lucency is seen on X-ray. There are no other cases in the literature of Brodie's abscess presenting like toxic synovitis. This case is relevant to pediatricians and orthopedists, particularly pediatric orthopedists.

As simple as it sounds? The treatment of simple bone cysts in the proximal femur in children and adolescents: Retrospective multicenter EPOS study of 74 patients.

Purpose: Simple bone cysts are among the most prevalent benign cystic tumor-like lesions in children. Proximal femoral simple bone cysts may require specific treatment because of increased fracture risk. With limited literature available on this specific localization, consensus regarding optimal treatment is lacking. We present a large international multicenter retrospective cohort study on proximal femoral simple bone cysts. Methods: All consecutive pediatric patients with proximal femoral simple bone cyst from 10 tertiary referral centers for musculoskeletal oncology were included (2000-2021). Demographics, primary treatment, complications, and re-operations were evaluated. Primary outcomes were time until full weight-bearing and failure-free survival. Results: Overall, 74 simple bone cyst patients were included (median age 9 years (range = 2-16), 56 (76%) male). Median follow-up was 2.9 years (range = 0.5-21). Index procedure was watchful waiting (n = 6), percutaneous procedure (n = 12), open procedure (n = 50), or osteosynthesis alone (n = 6). Median time until full weight-bearing was 8 weeks (95% confidence interval = 0.1-15.9) for watchful waiting, 9.5 (95% confidence interval = 3.7-15.3) for percutaneous procedure, 11 (95% confidence interval = -0.7 to 13.7) for open procedure, and 6.5 (95% confidence interval = 5.9-16.1) for osteosynthesis alone (p = 0.58). Failure rates were 33%, 58%, 29%, and 0%, respectively (p = 0.069). Overall failure-free survival at 1, 2, and 5 years was 77.8% (95% confidence interval = 68.2-87.4), 69.5% (95% confidence interval = 58.5-80.5), and 62.0% (95% confidence interval = 47.9-76.1), respectively. Conclusion: A preferred treatment for proximal femoral simple bone cysts remains unclear, with comparable failure rates and times until full weight-bearing. Watchful waiting may be successful in certain cases. If not feasible, osteosynthesis alone can be considered. Treatment goals should be cyst control, minimizing complications and swift return to normal activities. Therefore, an individualized balance should be made between undertreatment, with potentially higher complication risks versus overtreatment, resulting in possible larger interventions and accompanying complications. Level of evidence: Level IV, retrospective multicentre study.

Treatment of Unicameral Bone Cysts Utilizing the Sclerograft™ Technique.

PURPOSE: To evaluate the Sclerograft™ procedure, which is an image-guided, minimally invasive approach of chemical sclerotherapy followed by bone grafting of unicameral bone cysts (UBC). MATERIALS AND METHODS: A retrospective evaluation from August 2018 through August 2023 was performed at a single institution on patients that underwent the Sclerograft™ procedure for UBCs. Radiographic healing was evaluated utilizing the Modified Neer Classification. Two different regenerative grafts, CaSO4-CaPO4 and HA-CaSO4 were utilized. A total of 50 patients were evaluated with 41 patients grafted with CaSO4-CaPO4 and 9 patients grafted with HA-CaSO4. RESULTS: The average age of the patient was 12.1 years with an average radiographic follow-up of 14.5 months. Average cyst size was 5.5 cm in the largest dimension and average cyst volume was 20.2 cc. 42 out of 50 (84%) showed healed cysts (Modified Neer Class 1) on the most recent radiograph or MRI. Recurrences occurred on average at 7.2 months. Activity restrictions were lifted at 3-4.5 months post-procedure. Cyst stratification by size did not show a difference in recurrence rates (p = 0.707). There was no significant difference in recurrence rate between lesions abutting the physis compared to those that were not abutting the physis (p = 0.643). There were no major complications. CONCLUSIONS: The Sclerograft™ procedure is an image-guided approach to treating unicameral bone cysts, utilizing chemical sclerosis and regenerative bone grafting. The radiographic healing of cysts compares favorably to open curettage and grafting as determined utilizing previously published trials.

Percutaneous calcium sulfate injection versus localized scrape bone grafting: clinical effect comparison in titanium elastic nail treatment of pathological fracture of proximal humerus caused by unicameral bone cysts in children.

Objective: A retrospective study was conducted to compare the mid-term clinical efficacy between percutaneous calcium sulfate injection (PCSI) and localized scrape bone grafting (LSBG) in using titanium elastic nails treat humerus pathologic fractures caused by unicameral bone cysts in children. Methods: Humerus pathologic fracture patients with unicameral bone cysts in our pediatric orthopedic department from January 2015 to January 2020 were retrospectively analyzed. Patients were divided into two groups, namely the PCSI group and the LSBG group, based on the type of bone grafting material they received. Preoperative assessments were made in both groups using the Cyst Index and Cyst activity. During the perioperative phase, assessments were made regarding operative time, bleeding, postoperative VAS scores, and the frequency of reoperation within 2 years. Clinical outcomes were evaluated using the Capanna scale at the last follow-up, and the occurrence of re-fractures during the follow-up period. Results: A total of 22 patients were included, with a mean follow-up duration of 33.5 ± 5.8 months. No significant differences were found between the two groups in terms of Cyst Index and Cyst activity before the operation. The operative time, bleeding, and postoperative VAS scores in the PCSI group were found to be lower than those in the LSBG group (P < 0.05). The PCSI group also showed a higher frequency of reoperation within 2 years compared to the LSBG group (P < 0.05). However, no significant differences were observed between the two groups in terms of Capanna scale scores at the last follow-up and the incidence of re-fractures during follow-up. Conclusions: Both titanium elastic nails (TEN) combined with PCSI or LSBG were found to be safe and effective treatments for humerus pathologic fractures caused by unicameral bone cysts in children. PCSI is considered as a less invasive option with shorter operative times, less bleeding, and reduced postoperative pain, although it comes with the risk of multiple injections. On the other hand, LSBG is considered as a more invasive option for the treatment of active bone cysts but is associated with a lower recurrence rate.

Unicameral Bone Cysts: Review of Etiopathogenesis and Current Concepts in Diagnosis and Management.

Objective: This article aims to review the epidemiology, etio-pathogenesis and updates in clinical diagnostics and management of unicameral bone cysts (UBC). Methods: A computerized literature search using Cochrane database of systematic reviews, EMBASE and PubMed was performed. MeSH (Medical Subject Headings) terms used in searches included the following sub-headings: "unicameral bone cyst", "epidemiology", "etiology", "pathogenesis", "diagnosis", "management" and "surgery". Studies were analyzed based on clinical relevance for the practicing orthopedic surgeon. Results: UBC accounts for 3% of all bone tumors and is asymptomatic in most cases. Nearly 85% of cases occur in children and adolescents, with more than 90% involving the proximal humerus and proximal femur. Despite multiple theories proposed, the exact etiology is still unclear. Diagnosis is straightforward, with radiographs and MRI aiding in it. While non-surgical treatment is recommended in most cases, in those warranting surgery, combined minimal-invasive techniques involving decompression of cyst and stabilization have gained importance in recent times. Conclusion: There is variation in the diagnosis and treatment of UBCs among surgeons. Due to the vast heterogeneity of reported studies, no one method is the ideal standard of care. As most UBCs tend to resolve by skeletal maturity, clinicians need to balance the likelihood of successful treatment with morbidity associated with procedures and the risks of developing a pathological fracture. Study Design: Review Article.

Quistes óseos de localizacion inusual como causa de lumbalgia crónica en adultos / Bone cyst of unusual location as a cause of chronic back pain in adults

Se presenta el caso de un paciente con quistes en el hueso iliaco como causa atípica de lumbalgia crónica a la cual se puede enfrentar el reumatólogo, y se hará una revisión de la literatura sobre los tipos de quistes óseos y sus diagnósticos diferenciales. También se hará mención de sus opciones de tratamiento.

The case of a patient with cysts in the iliac bone is presented as an atypical cause of chronic low back pain that the rheumatologist may face, and a review of the literature on the types of bone cysts and their differential diagnoses will be made. Mention will also be made of your treatment options.

Evaluation of immediate and delayed surgery for pathological fracture due to unicameral bone cysts in children.

PURPOSE: Unicameral bone cysts (UBCs) are most often found when accompanied by a pathological fracture. In these cases, the doctor must determine the optimal timing for the surgery. The purpose of this study was to evaluate the outcome of immediate surgery as compared with delayed surgery in paediatric pathological fractures due to UBCs. METHODS: This retrospective study assessed the medical records of 65 patients between January 2012 and September 2016. Group A included 34 patients who underwent immediate surgery, including curettage, demineralized bone matrix and fixation with elastic stable intramedullary nailing. Group B included 31 patients who underwent the same surgery several months later. The outcome evaluations included the radiological changes, brace fixation time, cyst healing time, at the first-, third- and sixth month, and final visit. RESULTS: The mean brace fixation time was 26.3 days (sd 5.7) for group A and 53.8 days (sd .1) for group B (p = 0.012). According to radiological evaluations, 3/34 patients in group A and 5/31 in group B had recurrence after the first surgery. A second surgery was performed in all cases of recurrence, and all fractures were healed at the last visit. There was no significant difference in the recurrence rate between the two groups (p = 0.4631), and healing times were also similar (p = 0.6033). CONCLUSION: Both the immediate and delayed surgery were safe for the treatment of UBCs with fractures. We suggest immediate surgery for shorter fixation time and early activity. LEVEL OF EVIDENCE: IV.

Pediatric physeal slide-traction plate fixation for pathological distal femoral fracture caused by unicameral bone cyst in adolescents.

BACKGROUND: Most patients suffering from distal femoral unicameral bone cysts (UBCs) are adolescents that require an early return to normal activities, including school attendance and sports exercises. However, the optimal choice of implants for such patients remains controversial. This study evaluated the application of pediatric physeal slide-traction plate (PPSP) in the treatment of pathological distal femoral fracture caused by UBCs. METHODS: Between Jan 2014 and Jan 2016, 11 (male = 6, female = 5) patients were reviewed retrospectively. Age, sex, operative time, limb-length discrepancy (LLD), and valgus angulation were all recorded for every patient. RESULTS: The average age of 11 patients was 12.2 ± 1.1 years. The operating time was 94.8 ± 7.8 min. The postoperative hospital stay was 5 to 7 days. The epiphyseal morphology in the operative leg was nearly normal. The plate was removed in an average of 19.5 ± 3.1 months. The knee range of motion (ROM) was normal in 9 patients, whereas 2 female patients reported a loss of less than 10 degrees of ROM as compared to the contralateral knee joint. Breakage of plates or refracture did not occur in our cases. All patients had a follow-up of at least 24 months. At the latest follow-up visit, all patients walked without a limp. None of the patients manifested obvious LLD and valgus deformity. CONCLUSION: PPSP combined with curettage and bone grafting allows early mobilization and produces satisfactory outcomes for pathological fracture of distal femur secondary to UBCs in adolescents.

Cranial vault unicameral bone cyst.

Introduction: Unicameral bone cysts (UBC), also known as simple bone cysts, are common benign bone lesions filled with fluid, primarily occurring in children and adolescents. Although they can develop in any bone, UBCs usually affect the long bones.Materials & Methods: A 53 year old male patient was found incidentally to have a calvarian lesion in the parietal region overlying the superior sagittal sinus (SSS) (Figure 1). The differential diagnosis included a large arachnoid granulation, haemangioma of bone, a giant cell tumour or tuberculous infection. The patient was planned for elective surgery to remove the lesion and establish the diagnosis. Surgery was uneventful.Conclusion: To the best of our knowledge we describe the first case of UBC affecting the cranial vault. The patient underwent surgery.

Unicameral bone cyst in the pelvis: report of a case treated by placement of screws made from a composite of unsintered hydroxyapatite particles and poly-l-lactide.

Unicameral bone cysts are fluid-filled benign lesions that occur mostly in the long bones. Unicameral bone cysts in the pelvis are extremely rare. Continuous decompression using titanium or hydroxyapatite screws has been reported as a treatment. Screws made from a composite of unsintered hydroxyapatite particles and poly-l-lactide can be used for the treatment. An adolescent male patient presented with a unicameral bone cyst in the ilium extending to a region adjacent to the hip joint. As initial treatment, the cortex was fenestrated when the patient was 13 years old and ß-tricalcium phosphate implanted. The cyst first reoccurred when the patient was 15 years old and again when he was 17 years old. During the most recent treatment, unsintered hydroxyapatite particles and poly-l-lactide composite screws were placed, and no recurrence was observed during 2 years of follow-up. The slow biodegradability and absorbability of the screws may allow continuous drainage of unicameral bone cysts.

Inter-rater reliability of the radiographic assessment of simple bone cysts.

PURPOSE: To develop and evaluate the reliability of an explicit set of parameters and criteria for simple bone cysts (SBCs) and evaluate the reliability of single versus serial chronological reading methods. METHODS: Radiographic criteria were developed based on the literature and expert consensus. A single anteroposterior/lateral radiograph from 32 subjects with SBC were evaluated by three radiologists. A second reading was then conducted using revised criteria including a visual schematic. In the third reading the same images were assessed but radiologists had access to images from two additional time points. Inter-rater reliability was assessed after each reading using kappa (κ) and percentage agreement for categorical and binary parameters and intra-class correlation coefficient (ICC) for continuous parameters. RESULTS: Parameters that were revised with more explicit definitions including the visual schematic demonstrated consistent or improved inter-rater reliability with the exception of continuous cortical rim present and cyst location in the metaphysis and mid-diaphysis. Cortical rim displayed only slight reliability throughout (κ= -0.008 to 0.16). All other categorical parameters had a percentage agreement above 0.8 or a moderate (κ= 0.41 to 0.60), substantial (κ = 0.61 to 0.80) or almost perfect inter-rater reliability (κ = 0.81 to 1.0) in at least one reading. All continuous parameters demonstrated excellent inter-rater reliability (ICC > 0.75) in at least one reading with the exception of scalloping (ICC = 0.37 to 0.70). Inter-rater reliability values did not indicate an obviously superior method of assessment between single and serial chronological readings. CONCLUSION: Explicit criteria for SBC parameters used in their assessment demonstrated improved and substantial inter-rater reliability. Inter-rater reliability did not differ between single and serial chronological readings. LEVEL OF EVIDENCE: Not Applicable.

Free non-vascularized fibular graft reconstruction after resection of metacarpal unicameral bone cyst: A case report.

Unicameral bone cyst (UBC) or simple bone cyst (SBC) is a benign cystic lesion commonly found in the humerus and femur that is mainly encountered during childhood. The currently available treatments for UBC of the hand commonly involve curettage, bone grafting, partial resection with or without grafting, multiple drilling, fracture immobilization and observation alone, and steroid injection. We herein report a case treated with total resection of the cyst and non-vascularized fibular graft in a 9-year-old right-handed female patient. The patient presented with a chief complaint of a large, fast growing lump over the first metacarpal of the left hand. Flexion of the first metacarpophalangeal joint was limited. After the diagnosis was established with plain radiographs followed by biopsy, the cyst was completely removed by resecting the shaft of the metacarpal bone with preservation of the epiphyseal plate. A bone graft was obtained from the fibula and inserted in the gap, distally attached to the epiphyseal plate of the metacarpal and fixed with a Kirshner wire proximally. Radiographs revealed solid union of the bone graft to the epiphyseal plate at the head after 7 weeks, with improving function of the thumb. SBC or UBC of the metacarpal bone is very rare. A more aggressive method, such as in the case presented herein, may be necessary to treat this condition.

Healing bone lesion defects using injectable CaSO4 /CaPO4 -TCP bone graft substitute compared to cancellous allograft bone chips in a canine model.

CaSO4 /CaPO4 -TCP bone graft substitute has been shown to be effective for treatment of bone lesion defects, but its mechanical, histological, and radiographic characteristics have not been studied in direct comparison with a conventional treatment such as cancellous allograft bone. Thirteen canines had a critical-size axial defect created bilaterally into the proximal humerus. CaSO4 /CaPO4 -TCP bone graft substitute (PRO-DENSE™, Wright Medical Technology) was injected into the defect in one humerus, and an equal volume of freeze-dried cancellous allograft bone chips was placed in the contralateral defect. The area fraction of new bone, residual graft, and fibrous tissue and the compressive strength and elastic modulus of bone within the defects were determined after 6, 13, or 26 weeks and correlated with radiographic changes. The data were analyzed using Friedman and Mann-Whitney tests. There was more bone in defects treated with the CaSO4 /CaPO4 -TCP bone graft substitute compared to defects treated with cancellous bone allograft at all three time points, and the difference at 13 weeks was significant (p = 0.025). The new bone was significantly stronger and stiffer in defects treated with the CaSO4 /CaPO4 -TCP bone graft substitute compared to defects treated with cancellous bone allograft at 13 (p = 0.046) and 26 weeks (p = 0.025). At 26 weeks, all defects treated with CaSO4 /CaPO4 -TCP bone graft substitute demonstrated complete healing with new bone, whereas healing was incomplete in all defects treated with cancellous allograft chips. The CaSO4 /CaPO4 -TCP bone graft substitute could provide faster and significantly stronger healing of bone lesions compared to the conventional treatment using freeze-dried cancellous allograft bone. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 408-414, 2019.

Unicameral bone cysts: Current concepts.

Unicameral bone cysts (UBC) or simple/solitary bone cysts are benign fluid filled cavities that enlarge over time, resulting in thinning of the bone. Usually these cysts are reported in the metaphyseal areas of long bones with open physes. 85% of UBCs occur almost exclusively in children and adolescents. UBCs are more aggressive in the first decade of life and correspondingly the recurrence rate for these patients is four times that for adolescents. The proximal humerus and femur account for almost 90% of these cases. UBCs are classified as active when they are within 1 cm of the physis and latent as they progress to a diaphyseal location. Differential diagnoses for UBC include aneurysmal bone cyst, fibrous dysplasia, enchondroma, and intraosseous ganglia. By the time of skeletal maturity most UBCs tend to resolve. Nonoperative treatment may be a viable option for many patients with small or symptomatic lesions. Interventions include steroid injection, open curettage and bone grafting, decompression and percutaneous injection of marrow or graft substitutes.

Locking plate and fibular strut-graft augmentation in the reconstruction of unicameral bone cyst of proximal femur in the paediatric population.

PURPOSE: Several therapeutic strategies have been used for managing unicameral bone cyst (UBC) of the proximal femur. However, there is insufficient evidence to support one treatment over another, and the optimal treatment is controversial. This study aims at describing our experience with surgical reconstruction of paediatric UBCs of the proximal femur using a proximal locking plate and fibular strut allograft. METHODS: In total, 14 consecutive paediatric patients with Dormans types IB (four cases) and IIB (10 cases) UBC were assessed. Mean patient age was 8.6 ± 2.3 years, and mean follow-up period was 41.7 ± 29.8 months. Six patients (42.8%) were referred with a pathologic fracture. Clinical/radiological outcome and complication rates were evaluated at the final follow-up session. RESULTS: No cysts were Capanna's class III (recurrence) or IV (no response). Complete healing (Capanna's class I) was seen in ten cysts, while four other cysts healed with residual radiolucent areas (Capanna's class II). Mean healing period was 14.1 ± 5.1 (9-24 months). One patient had superficial infection, one heterotopic ossification, and one mild coxa vara, and mean Musculoskeletal Tumor Society (MSTS) score was 99.5%. CONCLUSION: According to our results, locking plate and fibular strut graft in Dormans classification types IB and IIB results in a favorable outcome in managing UBC of the proximal femur in the paediatric population.

Injection of Unicameral Bone Cysts with Bone Marrow Aspirate and Demineralized Bone Matrix Avoids Open Curettage and Bone Grafting in a Retrospective Cohort.

BACKGROUND: Many treatment options exist for unicameral bone cysts (UBC), without clear evidence of superiority. Meta-analyses have been limited by small numbers of patients in specific anatomic and treatment subgroups. The purpose of this study was to report the outcomes of injecting bone marrow aspirate and demineralized bone matrix (BMA/DBM) for the treatment of proximal humerus UBC. METHODS: Fifty-one patients with proximal humerus lesions treated by BMA/DBM injection were retrospectively reviewed from a single academic medical center. RESULTS: The mean number of injections performed per patient was 2.14 (range 1-5). Eleven patients underwent only one injection (22%), an additional 19 patients completed treatment after two injections (37%), four patients healed after three injections (8%), and one patient healed after four injections (2%). The cumulative success rate of serial BMA/DBM injections was 22% (11/51), 58% (30/51), 67% (34/51), and 69% (35/51). Eleven patients (22%) ultimately underwent open curettage and bone grafting, and five patients (10%) were treated with injection of calcium phosphate bone substitute. CONCLUSION: A BMA/DBM injection strategy avoided an open procedure in 78% of patients with a proximal humerus UBC. The majority of patients underwent at least 2 injection treatments. LEVEL OF EVIDENCE: Level IV retrospective cohort study.

An unusual case of proximal humeral simple bone cyst in an adult from secondary cystic change.

BACKGROUND: Simple bone cysts (SBC) have been documented to occur in adults with closed physeal plates, most commonly affecting the calcaneus in this patient subset. Although most authors theorize an association to trauma, etiology of simple bone cysts remains an enigma up to now. CASE PRESENTATION: A 26-year-old kickboxing coach sought consult for a painful right shoulder which on radiographs and magnetic resonance (MR) imaging showed a proximal humeral lesion with signs of ossification. The patient was lost to follow-up but again sought consult after 3 years for the recurring complaint. On repeat radiographs, computed tomography (CT) scan, and MR images, tumor enlargement with cystic findings typical of simple bone cyst were documented. Diagnostic aspiration of the lesion was firstly done, revealing straw-colored fluid. The patient then underwent intralesional curettage with alpha-tricalcium phosphate cement reconstruction of the lytic defect. No perioperative complications were incurred, and on latest follow-up at 3 years postoperatively, Musculoskeletal Tumor Society (MSTS) and visual analog scale (VAS) pain scores were 30/30 and 0/10, respectively. CONCLUSIONS: The authors believe their report provides support to a possible association to trauma of simple bone cysts occurring in the adult population with closed physes and suggest this subset of patients may require a different treatment approach from that for juvenile simple bone cysts.

Endoscopic resection and allografting for benign osteolytic lesions of the calcaneus.

BACKGROUND: Both unicameral bone cysts and intra-osseous lipoma of the calcaneus are rare entities which are mostly diagnosed due to unspecific heel pain, pathologic fracture or as an incidental finding. Minimally-invasive ossoscopy with endoscopic resection of the tumor followed by grafting can potentially minimize risks of open surgery and speed up convalescence. The objective of this study is to present a simple, safe and cost-effective surgical technique for endoscopic surgical treatment of benign osteolytic lesions of the calcaneus. DESCRIPTION OF TECHNIQUE: We present our modifications to previously described techniques of endoscopic curettage with a particular focus on intraosseous lipoma. The key point for grafting is the use of a funnel-shaped ear speculum facilitating the plombage with allogenic cancellous bone chips. PATIENTS AND METHODS: Between June 2013 and January 2015 ten consecutive patients underwent ossoscopy of the calcaneus. There were 4 cases of intraosseous lipoma and 6 cases of unicameral bone cyst. In a retrospective study, radiological results were analyzed using the Glutting-Classification, functional outcome was recorded with the AOFAS Hindfoot score. RESULTS: Radiographic follow-up and functional outcome showed good to excellent results. All lesions radiologically classified as "healed". AOFAS score (max. 100 pts) ranged from 74 to 100 (ø94.4 ± 9.3). CONCLUSIONS: This technique is a simple and safe procedure for benign osteolytic bone lesions of the calcaneus. Compared to its alternatives, grafting with allogenic cancellous bone might prove favourable in this localization for several reasons: Osteointegration, handling, availability and costs. Our preliminary investigations show promising results although further clinical and radiographic results are needed.