Treatment of unicameral bone cyst: systematic review and meta analysis

Conventional vs. endoscopic-assisted curettage of benign bone tumours. An experimental study

BACKGROUND

This experimental study aimed at directly comparing conventional and endoscopic-assisted curettage towards (1) amount of residual tumour tissue (RTT) and (2) differences between techniques regarding surgical time and surgeons' experience level.

METHODS

Three orthopaedic surgeons (trainee, consultant, senior consultant) performed both conventional (4x each) and endoscopic-assisted curettages (4x each) on specifically prepared cortical-soft cancellous femur and tibia sawbone models. "Tumours" consisted of radio-opaque polyurethane-based foam injected into prepared holes. Pre- and postinterventional CT-scans were carried out and RTT assessed on CT-scans. For statistical analyses, percentage of RTT in relation to total lesion's volume was used. T-tests, Wilcoxon rank-sum tests, and Kruskal-Wallis tests were applied to assess differences between surgeons and surgical techniques regarding RTT and timing.

RESULTS

Median overall RTT was 1% (IQR 1 - 4%). Endoscopic-assisted curettage was associated with lower amount of RTT (median, 1%, IQR 0 - 5%) compared to conventional curettage (median, 4%, IQR 0 - 15%, p = 0.024). Mean surgical time was prolonged with endoscopic-assisted (9.2 ± 2.9 min) versus conventional curettage (5.9 ± 2.0 min; p = 0.004). No significant difference in RTT amount (p = 0.571) or curetting time (p = 0.251) depending on surgeons' experience level was found.

CONCLUSIONS

Endoscopic-assisted curettage appears superior to conventional curettage regarding complete tissue removal, yet at expenses of prolonged curetting time. In clinical practice, this procedure may be reserved for cases at high risk of recurrence (e.g. anatomy, histology).

Minimally invasive treatment of benign osteolytic bone lesions with a Hartmann ear speculum: A surgical technique

This study introduces a novel and simple minimally invasive technique for treating benign osteolytic bone lesions. The standard treatment involves lesion removal and cavity filling with various materials. Minimally invasive approaches, including arthroscopy and CT-guided injection, have been described, but they pose challenges such as X-ray exposure and expansiveness. In this study, a new minimally invasive technique using a Hartmann ear speculum is presented. The technique was successfully applied in 10 patients with various benign tumors, demonstrating full healing and no recurrence at one-year follow-up. The presented approach combines simplicity, cost-effectiveness, and minimal invasiveness, making it a promising alternative option for treating benign bone lesions with low complication rates and surgical site morbidity. LEVEL OF EVIDENCE: IV.

Outcomes and complications of surgical treatment modalities for simple bone cysts of the humerus in children and adolescents

PURPOSE

The aim of this study was to evaluate and compare different surgical treatment modalities for simple bone cysts (SBC) of the humerus regarding their effectiveness and recurrence rate.

METHODS

In this retrospective study, patients who received surgical treatment for previously untreated primary SBCs of the humerus were analyzed. Demographic data, cyst-specific as well as treatment-specific parameters, complications, treatment failures, and recurrence rates were collected and correlated with different treatment modalities. Observed procedures were categorized as open procedure (n=20) or osteosynthesis alone (n=3). For the open procedure group, four subgroups could be defined.

RESULTS

Twenty-three patients were included. The mean age at diagnosis was 11.6 ± 2.5 years, and the mean postoperative follow-up was 3.9 ± 2.6 years (range 1.0-10.3). After surgical intervention, a total of five (21.7%) patients showed at least one recurrence. Fracture occurred in three (13.0%) cases. The incidence of treatment failure was significantly higher in the curettage, allograft, adjuvants group, with five (83.3%) of six cases showing recurrence, than in the other subgroups (≤ 25.0%) including the osteosynthesis alone group (p=.024). For the open procedure group, the failure-free survival rates were 80.0% after two years and 50.4% after five years. For the three cases treated by osteosynthesis alone, no failures were observed.

CONCLUSION

Open procedures showed similar failure rates except for the subgroup using curettage, allograft, and adjuvants which showed significantly higher treatment failure. Promising results were observed in the group which received solely osteosynthesis without cyst excision or filling, as no treatment failure was observed here.

Factors which can influence elastic stable intramedullary nailing removal in healed bone cysts in children

Elastic stable intramedullary nailing (ESIN) internal fixation is used clinically to treat pathological fractures of bone cysts in children. However, one of the most important complications was removal difficulty. In this study, we aim to analyse the factors which can influence ESIN removal in healed bone cysts in children. From April 2014 to November 2020, the clinical data of 49 children who underwent elastic stable intramedullary nail removal for pathological fractures of the bone cysts in our hospital were retrospectively analysed. The following data, including age, sex, pathological fracture site, with bone graft, number of ESINs, ESIN indwelling time, and extraosseous length of ESIN were collected, and univariate analysis and logistic regression analysis was performed. The frequency of difficulty in ESIN extraction was 44.90% (22/49). The univariate logistic regression analysis showed that age,ESIN indwelling time,with bone garft and extraosseous length of ESIN may be correlated with the difficulty in removing ESIN (P < 0.05), while sex, pathological fracture site, number of ESIN may not be correlated with the difficulty in removing ESIN (P > 0.05).The multivariate logistic regression analysis showed that the ESIN indwelling time was the independent influencing factor for difficulty in removing ESIN (P < 0.05). The factors influencing the ESIN removal in healed bone cysts in children include over 11.79 years old, the long indwelling time of the ESIN(over 10.5 months),with bone graft and short extraosseous length of ESIN(≤ 0.405 cm). These factors influencing ESIN removal in healed bone cysts in children should be considered.

Surgical management of proximal femoral unicameral bone cyst in children

Aims

The aim of this study is to evaluate the surgical treatment with the best healing rate for patients with proximal femoral unicameral bone cysts (UBCs) after initial surgery, and to determine which procedure has the lowest adverse event burden during follow-up.

Methods

This multicentre retrospective study was conducted in 20 tertiary paediatric hospitals in France, Belgium, and Switzerland, and included patients aged < 16 years admitted for UBC treatment in the proximal femur from January 1995 to December 2017. UBCs were divided into seven groups based on the index treatment, which included elastic stable intramedullary nail (ESIN) insertion with or without percutaneous injection or grafting, percutaneous injection alone, curettage and grafting alone, and insertion of other orthopaedic hardware with or without curettage.

Results

A total of 201 patients were included in the study. The mean age at diagnosis was 8.7 years (SD 3.9); 77% (n = 156) were male. The mean follow-up was 9.4 years (SD 3.9). ESIN insertion without complementary procedure had a 67% UBC healing rate after the first operation (vs 30% with percutaneous injection alone (p = 0.027), 43% with curettage and grafting (p = 0.064), and 21% with insertion of other hardware combined with curettage (p < 0.001) or 36% alone (p = 0.014)). ESIN insertion with percutaneous injection presented a 79% healing rate, higher than percutaneous injection alone (p = 0.017), curettage and grafting (p = 0.028), and insertion of other hardware combined with curettage (p < 0.001) or alone (p = 0.014). Patients who underwent ESIN insertion with curettage had a 53% healing rate, higher than insertion of other hardware combined with curettage (p = 0.009). The overall rate of postoperative complications was 25% and did not differ between groups (p = 0.228). A total of 32 limb length discrepancies were identified.

Conclusion

ESIN insertion, either alone or combined with percutaneous injection or curettage and grafting, may offer higher healing rates than other operative procedures. Limb length discrepancy remains a major concern, and might be partly explained by the cyst's location and the consequence of surgery. Therefore, providing information about this risk is crucial.

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.

Pathological fracture increases the risk of unsatisfactory functional results and avascular necrosis in children with proximal femur simple bone cysts

INTRODUCTION

Proximal femur simple bone cysts (SBCs) are rare in children, but with a risk of pathological fractures and the associated poor outcomes. This study aimed to evaluate the functional and radiographic outcomes of children with proximal femur SBCs.

PATIENTS AND METHODS

38 children with proximal femur SBCs treated surgically at our department, West China hospital, were enrolled in the study. Patients were divided into two groups according to whether pathological fractures presented before treatment. The non-fracture group received treatment of open curettage, cavity electrocauterization, bone grafting, and fixation (proximal femoral plate, intramedullary nail or Kirschner wire). The pathological fracture group received the same procedures of curettage, electrocauterization, grafting, and fixation. Autogenous iliac bone grafting was done in all cases, and the artificial bone was used as a supplementary based on the size of the cavity. Postoperatively, all patients underwent hip spica or similar orthosis immobilization for six weeks and received the same rehabilitation program after the removal of hip spica. Patients were evaluated by two independent observers, including the functional results based on the Ratliff's criteria, avascular necrosis, healing rate based on the Neer scoring system, coxa vara, and premature physeal arrest. We described the good outcome in Ratliff's criteria as "Satisfactory results", and fair and poor outcomes as "Unsatisfactory results." Grade 1 and grade 2 Neer results were termed as failures in treatment, and grades 3 and 4 were considered successes and healing.

RESULTS

38 patients with 38 hips (18 on the left side and 20 on the right side) were evaluated, including 9 females and 29 males, with a mean age of 9.0±2.6 years old (range, 5 to 14 years). There was no significant difference between these two groups in the baseline data of gender, age, side, grafting, staging, and fixation methods. The rate of unsatisfactory functional results in the pathological fractures group was 56.3% (9/16), significantly higher than that in patients without fracture (22.7%, 5/22. p= 0.047). There was also a significant difference in avascular necrosis of the femoral head between the pathological fractures group (7/16) and the group without fracture (2/22, p=0.021). Thirty cases presented with healing, including 13 in the fractures group and 17 in the non-fracture group (p=1.000), and eight cases were graded as failures (2 cases of grade 1 and 6 cases of grade 2). There were also no significant differences between these two groups in premature physeal arrest (2 in fracture group and 1 in non-fracture group, P=0.562), and Coxa vara (3 in the fracture group and 0 in non-fracture group, P=0.066).

CONCLUSIONS

Pathological fracture significantly increases the risk of unsatisfactory functional results and avascular necrosis of the femoral head in patients with femoral neck SBCs. Prophylactic treatment and fixation of SBCs in weight bearing proximal femur region is better to manage without complications than managing with pathological fractures.

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.

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.

Treatment and Outcomes of 4,973 Unicameral Bone Cysts: A Systematic Review and Meta-Analysis

» 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.

Benign Bone Tumors Beyond Osteoid Osteoma: Percutaneous Minimally Invasive Image-Guided Interventions

Painful benign bone tumors often adversely influence quality of life primarily due to skeletal-related events such as unremittable pain, pathologic fracture, neurologic deficit, as well as skeletal growth disturbance. Substantial advances in percutaneous minimally invasive interventions for treatment of painful benign bone tumors beyond osteoid osteoma have been established as safe, efficacious, and durable treatments to achieve definitive cure. This article details the available armamentarium and most recent advances in minimally invasive percutaneous interventions and the role of radiologists for the management of patients with benign bone tumors beyond osteoid osteoma.

Treatment of a calcaneal unicameral bone cyst by percutaneous CT-guided cement injection using a double-needle technique: A case report

Simple bone cysts (SBCs) are benign cavitary lesions that most commonly affect adolescent males in the first 2 decades of life. They are mainly asymptomatic but can manifest with pain or pathological fractures. Despite numerous proposed methods for managing calcaneal SBCs, the optimal approach toward these lesions remains controversial. Herein, we report a case of a 16-year-old girl with a calcaneal SBC. On local examination, tenderness was the only noteworthy sign. In an outpatient setting, under conscious sedation, 2 interosseous needles were simultaneously inserted into the cyst under the guidance of CT fluoroscopy. Without aspiration, a radiopaque bone cement mixture was injected into the cyst from 1 needle until serosanguineous fluid efflux from the second needle ceased. Over a 2-year follow-up period, the patient recovered without any complications. This novel technique has the potential to be used as a feasible and minimally invasive approach in the management of symptomatic unicameral calcaneal bone cysts.

Successful treatment of a benign, non-infected cyst in a dog by bone marrow injections

Bone cysts are rare orthopaedic problems in dogs. There are no clear treatment guidelines. A young male Shih Tzu was referred to Small Animal Clinic with fifth-degree lameness (5/5) of the left thoracic limb, and with swelling and deformation of the distal humeral region. The radiological assessment revealed an enlargement of the distal brachium and an extensive hypodense osteolytic lesion in the distal metaphyseal region of the humerus. Diagnosis of the bone cyst was formulated and treated with a mini-invasive method using autologous non-concentrated bone marrow injections. The treatment was successful, and at the three weeks, the cyst significantly changed its structure. The follow-up at 12 weeks after the first injection, and at one year revealed complete recovery. To our knowledge, this is the first evidence of a bone cyst in a young dog successfully treated with a minimally-invasive method by using a non-concentrated autologous bone marrow injection.

Allogenic Cancellous Bone versus Injectable Bone Substitute for Endoscopic Treatment of Simple Bone Cyst and Intraosseous Lipoma of the Calcaneus and Is Intraosseous Lipoma a Developmental Stage of a Simple Bone Cyst?

Simple bone cysts (SBCs) and intraosseous lipoma (IOL) of the calcaneus are rare tumor entities that are primarily diagnosed due to unspecific heel pain, incidental findings, or rarely due to pathological fractures. Compared to traditional open tumor resections, endoscopic resection of these benign tumors aims to minimize surgical morbidity and maximize surgical efficiency without compromising safety. Grafting is regularly performed to reduce the risk of recurrence and stimulate osseous consolidation of the lytic lesion. As the incidence is low and treatment strategies are heterogeneous, there is no clear consensus for the treatment of simple cysts or intraosseous lipomas of the calcaneus. The objectives of this study are (a) to present medium to long-term results after endoscopic resection and grafting with allogenic cancellous bone or bioresorbable hydroxyapatite and calcium sulfate cement, and (b) to add further evidence to the discussion of whether calcaneal SBC and IOL are the same entity at different developmental stages. Between 2012 and 2019, a total of 25 benign bone tumors consisting of 17 SBCs and 8 IOLs were treated by A.T. with endoscopic resection and grafting, comprising the largest cohort to date. For grafting, 12 patients received allogenic cancellous bone (group A) and 13 patients received injectable bone substitute (group B). Pre- and postoperative imaging using plain X-rays and MRI was retrospectively analyzed with a mean follow-up time of 24.5 months to assess tumor size, osseous consolidation (modified Neer classification), and tumor recurrence. A retrospective chart analysis focusing on adverse intra- and perioperative events and other complications associated with the surgical procedure was performed using the modified Clavien-Dindo classification (CD1-3). A total of 12/13 cases with allogenic bone grafting showed a Neer Type 1 osseous healing of the tumorous lesion after endoscopic resection, whereas only 5/11 cases with injectable bone substitute showed sufficient healing (types 1 and 2). There were three recurrent cysts (Neer 4) and two persistent cysts (Neer 3) after using injectable bone substitute. Two CD1 complications were observed in group A (prolonged wound drainage, sural neuritis) and eight complications were observed in group B (6× CD1, 2× CD3). At least two IOLs diagnosed preoperatively using MRI were ultimately identified as SBCs upon histopathologic examination. Allogenic cancellous bone grafting after endoscopic resection of calcaneal SBC or IOL showed a very low rate of complications and no tumor recurrence in our series. On the other hand, depending on the material used, injectable bone substitute showed a high rate of "white-out" (excessive drainage), resulting in multiple complications such as prolonged wound healing, insufficient permanent defect filling, recurrence, and revision surgery. Over time, calcaneal SBC may transform into IOL, exhibiting distinct features of both entities simultaneously during ossoscopy and histopathological analysis.

Allograft Versus Bioactive Glass (BG-S53P4) in Pediatric Benign Bone Lesions: A Randomized Clinical Trial

BACKGROUND

Benign bone cysts in children have a high risk of recurrence after bone grafting. The optimal treatment and filling material for these lesions are currently unknown.

METHODS

We compared cyst recurrence after intralesional curettage and filling with allograft versus bioactive glass (BG-S53P4; Bonalive) in a randomized clinical trial. The volume of recurrent cyst at 2-year follow-up was the primary outcome.

RESULTS

Of 64 eligible children, 51 (mean age, 11.1 years) were randomized to undergo filling of the cyst using morselized allograft (26) or bioactive glass (25). Twelve (46%) of the children in the allograft group and 10 (40%) in the bioactive glass group developed a recurrence (odds ratio [OR] for bioactive glass = 0.79, 95% confidence interval [CI] = 0.25 to 2.56, p = 0.77). The size of the recurrent cyst did not differ between the allograft group (mean, 3.3 mL; range, 0 to 13.2 mL) and the bioactive glass group (mean, 2.2 mL; range, 0 to 16.6 mL, p = 0.43). After adjusting for the type of lesion (aneurysmal bone cyst versus other), bioactive glass also did not prevent larger (>1 mL) recurrent cysts (adjusted OR = 0.42, 95% CI = 0.13 to 1.40, p = 0.16). The Musculoskeletal Tumor Society score improved significantly (p ≤ 0.013) from preoperatively to the 2-year follow-up in both groups (to 28.7 for bioactive glass and 29.1 for bone graft). Four (15%) of the children in the allograft group and 6 (24%) in the bioactive glass group required a reoperation during the follow-up (OR for bioactive glass = 1.74, 95% CI = 0.43 to 7.09, p = 0.50).

CONCLUSIONS

Filling with bioactive glass and with allograft in the treatment of benign bone lesions provided comparable results in terms of recurrence and complications.

LEVEL OF EVIDENCE

Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Pathological fracture of a solitary bone cyst in the calcaneus: a case series and literature review

INTRODUCTION

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.

MATERIALS AND 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.

Benign Bone Tumors: State of the Art in Minimally Invasive Percutaneous Interventions

Painful benign bone tumors most commonly affect pediatric patients and young adults. They may be associated with skeletal-related events such as intractable pain, pathologic fracture, neurologic deficit as a consequence of nerve or spinal cord compression, as well as growth disturbance. Consequently, they often result in diminished activity and adversely affect quality of life. There have been substantial recent advances in percutaneous minimally invasive image-guided interventions for treatment of painful benign bone tumors including thermal ablation (radiofrequency ablation, cryoablation, microwave ablation, laser photocoagulation, and high-intensity focused US ablation), chemical (alcohol) ablation, cementoplasty, and intralesional injections. The safety, efficacy, and durability of such interventions have been established in the recent literature and as such, the role of musculoskeletal interventional radiologists in the care of patients with benign bone lesions has substantially expanded. The treatment goal of minimally invasive musculoskeletal interventions in patients with benign bone tumors is to achieve definitive cure. The authors detail the most recent advances and available armamentarium in minimally invasive image-guided percutaneous interventions with curative intent for the management of benign bone tumors. ^© RSNA, 2022.

High tartrate-resistant acid phosphatase (TRACP 5b) level in cystic fluid is a significant prognostic marker for postoperative recurrence in solitary bone cysts

PURPOSE

The pathogenesis of cystic fluid storage in solitary bone cysts remains unclear. We aimed to compare the results of the biochemical analysis of cystic fluid with clinical findings. We identified a significant marker of postoperative recurrence.

METHODS

Twenty-seven male and eight female patients were studied; the median age at diagnosis was 11 (5-23) years. The mean follow-up period was 60 months (range: 14-146 months). Clinical information including sex, age, affected site, radiological findings of phase (active or latent), surgical procedure, outcome, and biochemical analysis of serum and cystic fluid was obtained.

RESULTS

The 5-year healing rate was 64.0%. Biochemical analysis revealed that total protein and albumin values in the cystic fluid were significantly lower, compared to those in the serum. Levels of bone turnover markers, such as alkaline phosphatase, bone-specific alkaline phosphatase, and tartrate-resistant acid phosphatase 5b were remarkably elevated in the cystic fluid than in the serum. R values were 0.127, 0.076, and 0.095 for alkaline phosphatase, bone-specific alkaline phosphatase, and tartrate-resistant acid phosphatase 5b, respectively. Areas under the receiver operating characteristic curves, calculated to assess the association of alkaline phosphatase, bone-specific alkaline phosphatase, and tartrate-resistant acid phosphatase 5b levels in the cystic fluid with postoperative recurrence, were 0.57, 0.51, and 0.70, respectively.

CONCLUSIONS

No clear correlation of bone turnover marker levels between the serum and cystic fluid was observed. The high tartrate-resistant acid phosphatase 5b level in the cystic fluid was associated with postoperative recurrence. The bone resorption caused by osteoclasts is considered to affect postoperative recurrence.

LEVEL OF EVIDENCE

Level IV.

Outcomes in Unicameral Bone Cyst Management Utilizing a Decision Tree Algorithm Approach

OBJECTIVE

To determine if utilization of a decision tree algorithm could improve the healing rate of unicameral bone cysts (UBCs).

METHODS

Creation of the decision tree algorithm was based on previous literature and assessment of our clinical practice. Demographic, treatment, and radiographic data were collected retrospectively. Radiographic healing was determined using the Neer classification. Healing rate, as well as clinical/radiographic characteristics, were compared based on adherence to the treatment algorithm.

RESULTS

Forty-seven subjects were included. Mean age at initial surgery was 10.0 ± 3.3 years in children following the algorithm and 9.1 ± 3.2 years in those deviating from the algorithm (p = 0.393). Follow-up was found to be similar among those following the algorithm (37.5 ± 15.8 months) and those deviating from the algorithm (45.2 ± 24.6 months), p = 0.38. Children who followed the algorithm healed at a rate of 75%, while children who deviated from the algorithm healed at a rate 67% (p = 0.552).

CONCLUSIONS

Although we reject our hypothesis that a decision tree algorithm for the management of UBCs in the pediatric population could improve the healing rate, we believe that we uncovered some utility in applying an algorithm to this pathology. Our algorithm was designed to minimize risk to the child and maximize healing with the least number of surgical events. Treating surgeons should consider this proposed pathway to determine the best treatment and to help families understand that these lesions rarely heal with a single-event surgery.

Are Fibular Allograft Struts Useful for Unicameral Bone Cysts of the Proximal Humerus in Skeletally Mature Patients?

BACKGROUND

Although most unicameral bone cysts (UBCs) are either successfully treated or have healed by the time of skeletal maturity, a small proportion of patients will have persistent UBCs beyond the age of skeletal maturity. More reliable methods are needed to treat persistent UBCs in the humerus because these cysts are associated with a high risk of fracture due to thinning of the humeral cortex. In this study, we evaluated whether inserting a fibular strut allograft into the humerus would be associated with healing of the cyst and union of associated pathologic fractures in skeletally mature patients with a UBC of the proximal humerus.

QUESTIONS/PURPOSES

(1) How effective is inserting a fibular strut allograft in the healing of proximal humerus UBCs in skeletally mature patients with bone cysts and associated fractures? (2) What are the functional results of this procedure? (3) What complications are associated with this procedure?

METHODS

Between 2005 and 2018, we surgically treated 23 skeletally mature patients with persistent humeral UBCs and any of the following indications: a progressive cyst that was not responsive to aspiration and 2 to 3 steroid injections, a cyst with a pathologic fracture, and a cyst at high risk of fracture. Of those, patients with a cyst located in the proximal humerus and a defect length more than 6 cm (n = 18) were considered eligible to be treated with insertion of a fibular strut allograft through a hole created in the greater tuberosity. A further two patients were excluded because they were treated by other surgical methods. From the remaining 16 patients, two patients were lost to follow-up before 2 years and could not be analyzed in this study. Another two patients had incomplete datasets, leaving 12 for analyses in this retrospective study. Three patients presented with a pathologic fracture. Complete filling of the cysts with bone within 24 months was regarded as healing, and after 24 months it was classified as delayed healing. Cyst consolidation with small residual areas of osteolysis was considered healed with residual radiographic appearance. Fracture union was determined by the clear observation of at least three of four cortical views bridged by bone in the radiographic follow-up 3 months after the operation. Fractures in which the cortices were not bridged by bone after 3 months were regarded as a delayed union. The functional outcome of the patients was assessed by the Musculoskeletal Tumor Society (MSTS) scoring system, with a total score ranging from 0 to 30. A higher score was indicative of less pain and better function. MSTS scores were obtained through a chart review by an orthopaedist who was not involved in the care administered.

RESULTS

At a median (range) follow-up of 57 months (33 to 87), the cyst was completely healed in nine patients and healed with residual cyst in the remaining three. Union was observed within 3 months in all patients who presented with a pathologic fracture. The median MSTS score of the patients was 30 (28 to 30). No postoperative complications such as persistent pain or re-fracture were observed.

CONCLUSION

The primary goal of treating a UBC of the proximal humerus is to prevent fracture of the affected bone; insertion of a fibular strut graft in this study met this goal. Therefore, we believe a fibular strut allograft insertion is worth consideration when treating proximal humeral UBCs in skeletally mature patients. Further studies will be needed to determine whether this approach has benefits compared with other treatment options.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

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.

Percutaneous Curettage and Local Autologous Cancellous Bone Graft: A Simple and Efficient Method of Treatment for Benign Bone Cysts

BACKGROUND

Several treatment modalities have been reported to minimize the recurrence after surgical treatment of benign bone cysts. In this study, we evaluated local tumor control, recurrence rate, and bone healing of benign bone cysts after treatment with a simple technique, percutaneous curettage and a local autologous cancellous bone graft.

METHODS

Retrospective analysis of the records of 16 patients diagnosed with benign bone cysts between 2003 and 2010. We documented the demographic data, radiographic signs of healing (progressive decrease in radiolucency, remineralisation, ossification, consolidation of the cyst, and reconstitution of the bone), healing rate, postoperative complications, and recurrence.

RESULTS

Seven of the 16 patients (43.75%) were diagnosed with a simple bone cyst (SBC), while nine (56.25%) had an aneurysmal bone cyst (ABC). On average, radiographic signs of healing were present within 3-6 months, but in two patients these signs presented after 16 months. During the follow-up period, there was no difference in the healing rate between patients with SBC and ABC; no signs of deep or superficial wound infection, no postoperative fracture, and no recurrence in any case over an average of 6.3 years of follow-up.

CONCLUSION

Treatment of benign bone cysts (SBC/ABC) with minimally invasive percutaneous curettage and a local autologous cancellous bone graft is a simple and effective modality with a promising outcome in the local control of recurrence and in enhancing bony consolidation.

Minimally Invasive Treatment for Unicameral Bone Cysts with Chemical Sclerosis and Bone Graft Substitute: A Preliminary Report

PURPOSE

Unicameral bone cysts (UBCs) are benign lesions that primarily occur in childhood and can present with pain, pathologic fracture and growth disturbances. Existing treatment approaches for the management of UBCs are highly variable and recurrence is not uncommon. This study seeks to evaluate near-term outcomes of an image-guided, minimally invasive combination of chemical sclerotherapy and synthetic grafting as a novel outpatient management treatment option for UBCs.

MATERIALS AND METHODS

Retrospective evaluation from August 2018 to July 2020 of fourteen pediatric patients, ages 5-14 years, undergoing treatment for a UBC, at a single institution. All UBCs were treated in a single, minimally invasive, image-guided procedure using percutaneous needle access into the UBC followed by chemical sclerotherapy and injection of regenerative synthetic graft. Patients were followed clinically and with serial radiographs to evaluate for healing and complications, with an average follow-up of 13.7 months. Descriptive statistics were performed.

RESULTS

Twelve of 14 (85.7%) patients showed Modified Neer classification class 1 or 2 healed cysts at their most recent follow-up. There were two recurrences. All patients were pain-free and returned to normal physical activity on average within 2.0 months, and all patients with healed cysts remained asymptomatic at the most recent follow-up. There were no complications related to the procedures.

CONCLUSIONS

Image-guided chemical sclerosis and bone grafting is a minimally invasive treatment option for unicameral bone cysts and compares favorably to other existing treatment options. The preliminary findings of this technique are promising as an alternative management option for UBCs.

Steroid Injection and Biomarker Levels in the Treatment of Unicameral Bone Cysts: Can we Estimate the Result?

BACKGROUND

Steroid injection is a common method in the treatment of unicameral bone cysts (UBC). In this study, the relationship between the clinical results and inflammatory molecules' levels in the cyst fluid was evaluated after three repeated steroid injections in UBC subjects.

METHODS

Twenty-one patients diagnosed with UBC were treated with methylprednisolone acetate (MPA) injections. Patients were given three injections, each containing MPA, 6-8 weeks apart. Plain radiographs were obtained and cyst healing was evaluated according to modified Neer classification. Cyst fluid samples were taken. Samples were taken at first and last operations and were studied using the ELISA method to examine IL-1β, PGE2, MMP-1, and VEGF-A levels.

RESULTS

There were 17 and 4 cases localized to the humerus and femur, respectively. The mean follow-up period was 36.9 months. Complete recovery was achieved in 13 patients (61.9%) receiving MPA. Four patients (19%) recovered with residual lesions. One patient (4.7%) did not respond to steroid injections at all. In three patients (14.2%) the cyst recurred. Results were satisfactory in 17 patients (80.9%) and totally unsuccessful in 4 patients (19%). IL-1β, PGE2, and MMP-1 levels in cyst fluid were not affected by injection (p > 0.05), but VEGF-A levels decreased significantly with cyst healing (p = 0.01).

CONCLUSION

Steroid injection is a good choice in the treatment of UBC because of its less aggressive and relatively good outcome. It may be considered to evaluate the response to treatment by performing biomarker monitoring especially VEGF-A in repeated injections.

LEVEL OF EVIDENCE

Level II study.

Limb Length Discrepancy and Angular Deformity due to Benign Bone Tumors and Tumor-like Lesions

Benign bone tumors and tumor-like lesions are frequently diagnosed in children and adolescents. The immature skeleton is at risk for growth disturbances and deformity because of the effects of the lesions on normal bone architecture and the physis. The development, manifestation, and severity of the limb length inequality and deformity differs between the various bone pathologies. Distraction osteogenesis, osteotomy, and guided growth are key tools in the treatment of limb inequality and deformity using a combination of external and internal fixation devices.

Case Report: First Evidence of a Benign Bone Cyst in an Adult Teckel Dog Treated With Shark Teeth-Derived Bioapatites

Bone cysts are a very rare orthopedic pathology in veterinary medicine, the general prevalence of which is unknown. A unicameral bone cyst was diagnosed in an adult female Teckel dog with a limp that was treated surgically by filling the defect with marine bioapatites. The treatment was effective and at 8 weeks the defect had remodeled 50.24%. Eighteen months after surgery, the defect had remodeled 94.23%. The limp disappeared after surgery, and functional recovery was good in all stages after surgery. No adverse reactions were observed at the local or systemic level. This is the first report of a benign bone cyst in an lame adult female Teckel successfully treated with a novel marine bioapatite.

Elastic intramedullary nailing combined with methylprednisolone acetate injection for treatment of unicameral bone cysts in children: a retrospective study

PURPOSE

The aetiology of unicameral bone cysts (UBCs) is unclear. This study aims to evaluate the feasibility of elastic intramedullary nailing (EIN) combined with injections of methylprednisolone acetate (MPA) for the treatment of UBCs in children.

METHODS

We retrospectively analyzed 53 children with UBCs in our hospital between January 2010 and April 2016. A total of 24 patients (Group A) were treated by EIN and MPA, whilst 29 patients (Group B) were treated by curettage, bone grafts and EIN fixation. The radiographs of the UBCs were evaluated following the Capanna criteria. All patients were followed-up on the third, sixth, 12th, 24th and 36th months. Fixation time, hospitalization time and complications were evaluated.

RESULTS

In Group A, the mean number of MPA injections was 1.8 (1 to 3). Based on radiographic evaluation, eight patients were healed (Capanna grade I), 14 were healed with residual cysts (Capanna grade II), one showed recurrence (Capanna grade III) and one showed no response to the treatment (Capanna grade IV). In Group B, 11 patients were evaluated as Capanna grade I, 12 as Capanna grade II, three as Capanna grade III and three as Capanna grade IV. There was significant difference in the early postoperative function activity (p < 0.001), hospitalization time (p = 0.028), blood loss during surgery (p < 0.001) and surgery time (p < 0.001).

CONCLUSION

The combination of EIN and MPA for the treatment of UBCs in children is feasible, has little operative trauma, short surgery time, short hospitalization time, less blood loss and a low risk of incision infection.

LEVEL OF EVIDENCE

III.

Efficacy of Lesion Specific Portals in Endoscopic Treatment of Calcaneal Bone Cyst: A Case Report and Literature Review

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.

Comparison of three treatment methods for simple bone cyst in children

BACKGROUND

The unicameral bone cyst (UBC) is a kind of benign tumor whose clinical treatments and efficacy are controversial. The purpose of this study was to evaluate the efficacy of the elastic stable intramedullary nail (ESIN), the injection of autologous bone marrow (ABM), and the combination of ESIN and ABM in the treatment of bone cyst in children.

METHODS

Eighty-three cases with simple bone cyst were analyzed retrospectively. Twenty-eight cases were treated with ABM. Twenty-eight cases were treated with ESIN. Twenty-seven cases were treated with ABM and ESIN. All cases were diagnosed through X-ray, CT, or MRI scans. For the suspicious ones, the pathological biopsy was performed for an accurate diagnosis. X-ray examinations were carried out for the postoperative follow-up. Capanna criteria for bone cyst was used for postoperative evaluation of three methods.

RESULTS

All cases accomplished the follow-up. The effective rate of the ABM + ESIN group was significantly higher than that of the ABM group (P < 0.05), and the cure rates of the ESIN group and the ABM + ESIN group were higher than that of the ABM group (P < 0.05, respectively). The cure time in the ESIN group was lower than that of the other two groups (P < 0.05, respectively). The times for admission were 2.0 ± 0.0 in the ESIN group, 5.7 ± 1.9 in the ABM group, and 4.7 ± 2.4 in the ABM + ESIN group (P < 0.05 when compared with each other).

CONCLUSIONS

The method of ABM combined with ESIN for children's bone cyst has the highest effective rate and curative rate. For the individual method, ESIN has a higher effective rate and curative rate than that of ABM. Meanwhile, it has the fewest time of hospitalization.

FUS-NFATC2 or EWSR1-NFATC2 Fusions Are Present in a Large Proportion of Simple Bone Cysts

A simple bone cyst (SBC) is a benign bone lesion of unknown etiology. It can be differentiated from an aneurysmal bone cyst (ABC) by radiologic and histopathologic features, as well as by the absence of fusions of the USP6 gene characteristic of an ABC. In an attempt to differentiate between ABC and SBC in a recurrent bone cyst, we performed targeted RNA sequencing and found an EWSR1-NFATC2 fusion and no fusion of the USP6 gene. We subsequently analyzed additional 10 cysts, consistent with SBCs after radiologic-pathologic correlation, for the presence of an NFATC2 gene fusion, by targeted RNA sequencing, reverse-transcription polymerase chain reaction (RT-PCR) and Sanger sequencing, and fluorescent in situ hybridization. Targeted RNA sequencing showed a FUS-NFATC2 fusion in 4 of 11 SBCs and an EWSR1-NFATC2 fusion in 2 of 11 SBCs. No fusion was identified in 3 SBCs and the analysis was not successful in 2 SBCs because of the low quantity or poor quality of isolated RNA. All the 6 fusions detected by targeted RNA sequencing were confirmed by RT-PCR and Sanger sequencing, and 5 of the 6 fusions by fluorescent in situ hybridization. An additional FUS-NFATC2 fusion was identified by RT-PCR, Sanger sequencing, and fluorescent in situ hybridization in 1 of the 3 cases negative for fusions by targeted RNA sequencing. At least a large subset of SBCs represents cystic neoplasms characterized by FUS-NFATC2 or EWSR1-NFATC2 fusions, which also define a group of distinct, rare "Ewing-like" sarcomas that predominantly arise in long bones. Our results provide additional evidence of the existence of benign lesions with FUS-NFATC2 or EWSR1-NFATC2 fusions. Although they can recur locally in a nondestructive manner, their clinical course and possible relation to sarcoma with EWSR1-NFATC2 or FUS-NFATC2 fusion remains to be elucidated.

Which one of the benign tumors and tumor-like lesions located in long bones needs prophylactic fixation during surgery?

Objectives

This study aims to define the simultaneous prophylactic fixation indications of benign tumors and tumor-like lesions located in long bones that were treated by curettage and grafting/cementing.

Patients and methods

Fifty-six patients (33 males, 23 females; mean age 30.9±15.9; range, 15 to 65 years) who were treated by curettage and grafting or cementation for their benign tumors or tumor-like lesions in long bones between January 2013 and June 2016 were retrospectively analyzed. Age, sex, anamnesis and physical examination findings, histopathologic diagnosis, lesion localization, pre- and postoperative imaging results and follow-up data were all analyzed. The patients were divided into two groups as those with and without postoperative fracture.

Results

The most common localization was femur (38%). The mean tumor diameter was 6.8±2.2 (range, 2.6 to 12.6) cm and volume was 58.3±45.0 (range, 6 to 177) cm³. Postoperative fracture occurred in 14 patients. The lesion diameter and volume of the patients in postoperative fracture group were significantly higher compared to group without postoperative fracture (p=0.034 and p=0.004, respectively). A volume value greater than 67 cm³ and ages over 35 years were found to be associated with a higher rate of fracture for all lesions.

Conclusion

In the postoperative period, patients with benign tumors or tumor-like lesions of long bones had a higher fracture risk if the volume value was greater than 67 cm³ and the age was over 35 years. Prophylactic fixation may be suggested for these patients.

Predictive Effect of Helicobacter pylori in Gastric Carcinoma Development: Systematic Review and Quantitative Evidence Synthesis

Helicobacter pylori (H. pylori) is a bacterial pathogen implicated in gastritis, gastric ulceration, and gastric carcinoma. This study aimed to synthesize literature in providing evidence on the causative role of H. pylori in gastric carcinoma development. This study is based on assessing public literature using an applied meta-analysis, namely, quantitative evidence synthesis (QES). The analytic procedure uses DerSimonian-Laird, including assessing heterogeneity. The QES also utilizes meta-regression and the environmental effect associated with H. pylori in gastric cancer development. Eighteen studies are included in the QES. There is increased prevalence of H. pylori exposure among the cases. The heterogeneity between the CES and individual effect sizes is also significant. Despite controlling for the confoundings, there is increased exposure to H. pylori among the gastric cancer cases, regardless of the differences in the geographic location. H. pylori in this synthesized literature illustrates the contributory role of this microbe in gastric carcinoma. Additionally, regardless of geographic locale, namely, South Korea or Spain, H. pylori is implicated in gastric cancer development.

Synthetic Bone Graft Substitute for Treatment of Unicameral Bone Cysts

BACKGROUND

Treatments for unicameral bone cysts (UBCs) have high documented failure rates (27% to 63%) because of recurrence or persistence of the cyst, similar to nonoperative management. Recent evidence suggests that filling of the defect with a synthetic bone graft substitute (SBGS) supports the weakened cortex and promotes new bone growth. A calcium sulfate, brushite, calcium phosphate, composite graft material (PRODENSE, Wright Medical, Memphis, TN) has been evaluated as a substitute for autogenous or allogenous graft in animal and human studies. The purpose of this study was to compare the rates of revision surgery in patients treated for UBCs with an SBGS compared with historical treatments with allograft or autologous bone marrow aspirate.

METHODS

The authors reviewed 27 of 33 patients (age, 6 months to 21 years) an average of 121 months (range, 32 to 228) after filling of a UBC with an injection of SBGS (n=18) versus allograft or autologous bone marrow aspirate (n=9) between June 2008 and December 2017. Six patients with no follow-up were excluded. Groups did not differ in age at surgery, sex (19/27 male), history of pathologic fracture (22/27), or previous treatments (11/27). The primary outcome was the rate of revision surgery. Secondary outcomes included revision surgery-free survival as evaluated by the log-rank test, rate of postoperative fracture, persistent cysts, continued pain, and/or growth disturbance at the final follow-up.

RESULTS

Seven of 9 patients treated with allograft or autograft underwent revision surgery for postoperative pathologic fracture (n=2) or resorption of the graft (n=5) compared with 2 of 18 patients injected with the SBGS, both treated for graft resorption. The use of SBGS was associated with a decreased need for revision surgery over all time periods (hazard ratio, 0.14; 95% confidence interval, 0.03-0.05). There was no significant difference between postoperative fracture (2/18 vs. 2/9), persistent cyst (7/18 vs. 5/9), pain (0/18 vs. 2/9), or growth disturbance (1/18 vs. 3/9).

CONCLUSIONS

Treatment of UBCs with SBGS may decrease reoperation rates. Initial radiographic appearance after SBGS treatment shows solid structural support, followed by new bone formation. This appearance may lead to a less aggressive approach in considering revision surgery.

LEVEL OF EVIDENCE

Level III-retrospective comparative study investigating the results of treatment.

Possible pathogenesis of calcaneal bone cysts

INTRODUCTION

Recent literature indicates that calcaneal bone cysts have different clinical features compared to long bone cysts. Yet, previous studies have mainly focused on pathogenesis of long bone cysts. In this study, the pathogenesis of calcaneal bone cysts was investigated from radiological and pathological findings.

MATERIALS AND METHODS

Patients comprised 18 males and 6 females diagnosed with calcaneal bone cysts at a median age ± standard deviation of 13.0 ± 3.6 years. Plain radiographs, computed tomography, magnetic resonance imaging, cystography, bone scintigraphy, and pathology were reviewed.

RESULTS

All cysts occupied the central triangular area of the bone, with six extending posteriorly and two developing anteriorly. Fifteen of 20 cases (75%) showed the expanded foramen structures at the anterior margin of the posterior facet. According to cystography, four cysts showed absence of leakage to subtalar joint. Cystic fluid caused chronic haemorrhaging in 18 cases and pathologically detected cholesterol clefts were noted in 14 cases.

DISCUSSION

The location of the expanded foramen structures was consistent with the nutrient foramens of the sinus tarsi artery in the unaffected population. Hence, initial cysts may originate from the collapse of the sinus tarsi artery. Subsequent haemorrhage may extend into the central triangle area, which is biomechanically free of stress. Because of poor bone remodelling, degenerative change of the haemorrhage is prolonged. The results of this study showed that circulation collapse of the sinus tarsi artery and mechanical factors are important in the formation of calcaneal bone cysts.

A Preliminary Study on the Mechanical Reliability and Regeneration Capability of Artificial Bone Grafts in Oncologic Cases, With and Without Osteosynthesis

Several bone grafts are available for clinical use, each with their own peculiar biological and mechanical properties. A new bone graft was obtained by combining mineral structures from natural bovine bones with bioresorbable polymers and cellular nutrients. The study aims to evaluate the clinical, biological and structural properties of this bone graft and its reliability in orthopedic oncology. 23 adult patients (age range 18–85 years) were treated between October 2016 and December 2018; the oncologicdiagnoses were heterogeneous. After surgical curettage and bone grafting, a clinical-radiological follow up was conducted. Radiographs were used to evaluate graft integration according to the usual bone healing and oncologic follow up. Local complications (infection, local recurrence, wound dehiscence, fracture or early reabsorption) were evaluated. The mean followup was of 18.34 ± 4.83 months. No fracture or infection occurred. One case of patellar Giant Cell Tumor (GCT) and one of proximal tibia low-grade chondrosarcoma recurred after about one year. Two wound dehiscences occurred (one required a local flap). Follow-up X-rays showed good to excellent graft integration in most patients (20 out of 21). The investigated graft has a mechanical and structural function that can allow early weight-bearing and avoid a preventive bone fixation (only needed in four patients in this series). The graft blocks are different for shapes and dimensions, but they can be customized by the producer or sawcut by the surgeon in the operating theatre to fit the residual bone cavity. The complication rate was low, and a rapid integration was observed with no inflammatory reaction in the surrounding tissues. Further studies are mandatory to confirm these promising results.

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.

Percutaneous cyst aspiration with injection of two different bioresorbable bone cements in treatment of simple bone cyst

INTRODUCTION

Simple bone cysts (SBCs) are common in children and adolescents. The risk of refracture and the probability of spontaneous healing in SBCs are mainly dependent on the activity of the cyst and can be quantified with the Cyst-Index. Avoiding pathological fractures is the primary goal. Our study presents a comparison of two different bioresorbable bone graft substitutes (BGSs) in the minimally-invasive treatment of SBC in the active stage by percutaneous cyst aspiration and injection.

METHODS

Between 2006 and 2017, 38 patients (aged two to 37 years; mean age 12.4 (sd 5.6)) were treated with percutaneous cyst aspiration and refilled with bioresorbable BGSs in three hospitals. The cysts of 21 patients (11 humerus, five femur, four calcaneus, one fibula) were refilled with porous beta-tricalcium phosphate (PB-TP group) (ChronOS Inject) and of 17 patients (nine humerus, six femur, one calcaneus, one fibula) with hydroxyapatite/calcium sulphate (H/CS group) (CERAMENT|BONE VOID FILLER). There were 13 (62%) preceding fractures in the PB-TP group and eight (47%) in the H/CS group. The follow-up of all patients was at least two years. During follow-up, radiological healing (modified Neer classification), activity level, refracture rates, recurrence rates, resorption period and complications were analyzed.

RESULTS

In all, 21 patients treated with PB-TP group experienced 27 operations (one refracture, three recurrences and one persistent cyst). A total of 17 patients treated with H/CS experienced 20 operations (one refracture and one recurrence). After six weeks, 95% in the PB-TP group returned to unrestricted activity with one refracture in the femur due to insufficient biomechanical stability and all returned to unrestricted activity in the H/CS group. Partial or complete radiological response was observed in 81% after 13 months (sd 3.4). Three recurrences (14%) occurred in the PB-TP group and one recurrence (6%) occurred in the H/CS group. The refracture rates were similar in both groups; one (5%) in the PB-TP group and one (6%) in the H/CS group. All H/CS treated cysts showed completed resorption after two years, whilst in PB-TP treated cysts no resorption occurred in five cases (25%) (p = 0.031). Two (10%) wound infections occurred in the PB-TP group and no infections occurred in the H/CS group.

CONCLUSION

Both PB-TP and H/CS can provide stability and prevent refracture in patients with single bone cysts at the upper extremity or the foot. For the proximal femur, additional stabilization is necessary, due to the weight-bearing and associated high refracture rate. The H/CS bone graft substitute has a better resorption rate than the PB-TP graft.

LEVEL OF EVIDENCE

III.

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.

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.

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 β-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.

Calcium Sulfate/Calcium Phosphate Bone Void Filler in the Treatment of Bilateral Adolescent Unicameral Calcaneal Bone Cysts: 36-Month Follow-Up

A 36-month follow-up of the management of bilateral adolescent unicameral bone cysts in a high school gymnast treated with a calcium sulfate/calcium phosphate (CSCP) bone void filler (BVF) is presented. The more developed left calcaneal cyst was managed with a traditional, open approach consisting of allogenic bone graft, CSCP BVF mixed with platelet-rich plasma. The less developed right calcaneal cyst was managed with a less used approach, a percutaneous bone cortex incision with only the CSCP BVF. The rationale for the selection between the open and percutaneous approaches, long-term BVF incorporation, and positive patient outcome allowing a quick return to athletics are presented.

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.

Comparison of three surgical treatment options for unicameral bone cysts in humerus

Treatment of unicameral bone cysts (UBC) in the humerus with drainage screws is scarcely reported in the literature. The aim of this retrospective study was to compare drainage screws and alternative treatment methods with respect to the number of required surgical procedures to achieve sufficient UBC healing, postoperative fractures/recurrences/complications, and radiological outcome. Medical archives of two tertiary orthopedic referral centers were screened for all patients who were treated surgically for humeral UBC in the period 1991-2015 with a histologically/cytologically confirmed diagnosis. Sex, age, all surgical procedures, fractures, complications, recurrences, and the final radiological outcome were compared between patients treated with drainage screws, elastic intramedullary nails, or curettage with optional grafting. The study included 106 operated patients with a mean age of 10.3 years, with a mean follow-up of 5.7 years. The average number of UBC-related surgical procedures in sex-matched and age-matched treatment groups was 2.7 with drainage screws, 2.8 with intramedullary nails, and 3.5 with curettage/grafting (P=0.54). Intramedullary nails (odds ratio 0.20) and older age (odds ratio for each year 0.83) predicted a lower risk of postoperative UBC recurrence. Patients with drainage screws had the highest UBC recurrence rates and the lowest rates of changed initial treatment method. There was no difference between the treatment groups in the postoperative fracture rate, complications, or the final radiological outcome. UBC treatment in the humerus therefore requires approximately three surgical procedures, irrespective of the treatment modality chosen. Adding an elastic intramedullary nail to a humeral UBC cyst may reduce recurrence risk and prevent further fractures. Level of Evidence: Level III - therapeutic retrospective comparative study.

Cartilage-sparing Arthroscopic Technique for Curettage and Bone Grafting of Cystic Lesion of Talus -A Case Report

INTRODUCTION

True cysts in talar body are extremely rare lesions and their treatment options are yet undefined. The standard of care for a large symptomatic talar bone cyst comprises debridement and bone grafting, often requiring extensive soft tissue dissection, damaging talar cartilage, and sometimes, malleolar osteotomy. Alternatively, an arthroscopic debridement of the cyst cavity with bone grafting may be performed, sparing talar cartilage. Here, we describe such a case of a talar body cyst treated successfully by arthroscopic technique.

CASE REPORT

A 12-year-old boy presented with unicameral bone cyst in the body of talus, with fracture of the subchondral bone. Radiological evaluation suggested a simple bone cyst (SBC). Thereafter, posterior ankle arthroscopy was performed and the cyst was approached through posteriortalar process. Debridement of the cystic lesion was done along with curettage, sparing a thin rim of surrounding subchondral bone. The articular cartilage was found intact on both superior and inferior aspects. Subsequently, the defect was filled arthroscopically with cancellous bone graft harvested from the ipsilateral calcaneum through osteochondral autograft transfer system.

CONCLUSION

Outcome of the procedure was assessed clinically as well as radiologically. The histopathological report confirmed the lesion to be a SBC. The child was asymptomatic and resumed sports in school by 6 months. The cystic lesion of talus healed completely by 8 months. According to the modified Neer classification, the lesion had 'healed' radiologically.

Pathological Fracture of Distal Humerus due to a Simple Bone Cyst Managed with Fibula Grafting and Osteosynthesis

INTRODUCTION

Simple bone cyst (SBC) is the most common cause of pathological fracture in children. The most common sites are proximal humerus and proximal femur. There is no specific protocol in the management of pathological fractures with SBC. Treatment options include intralesional injection of steroids and bone marrow aspirate, percutaneous or open curettage of the lesion with or without bone grafting.

CASE REPORT

We report a case of pathological fracture of distal humerus due to SBC in a 16-year-old male. The fracture was treated surgically. Open reduction was done; curettage of cyst wall followed by non-vascularized fibula strut grafting was done and fixed with bicolumnar plating. Early post-operativemobilization was started. The patient had good outcome with incorporation of graft and healing of fracture and lesion.

CONCLUSION

Unstable pathological fractures due to SBC require osteosynthesis and curettage of lesion with bone grafting. Stable fractures can be managed conservatively.

Simple Bone Cyst of Rib

Simple bone cyst is a benign lytic lesion usually encountered in children and adolescents. It is a cystic, fluid-filled lesion that usually involves the metaphysis of the long bones. Simple bone cyst of the rib is very rare, with few cases reported in the literature. Here we describe an interesting case of a simple bone cyst of the sixth rib in a 15-year-old girl that was managed successfully with surgical excision.