A comparative study for the treatment of simple bone cysts of the humerus: open curettage and bone grafting either without instrumentation or with intramedullary nailing

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.

Simple bone cysts of the proximal humerus presented with limb length discrepancy: A case report

BACKGROUND

Simple bone cysts (SBC) are benign tumor-like bone lesions typically identified in children. While SBC may lead to growth disturbances or growth arrest, such cases are uncommon. The mechanisms behind these observations remain unclear. Additionally, research on the etiology of SBC remains inconclusive, and there has been no consensus on the appropriate timing and methodology for treatment.

CASE SUMMARY

Here, we present our experience in the successful surgical management of a 10-year-old girl with SBC, who presented with a pathological fracture complicated by malunion of the displaced fracture, varus deformity, and limb length discrepancy. We hypothesized two possible etiologies for the patient's growth arrest and subsequent humerus varus deformity: (1) Direct disruption of the physis by fluid from the cyst itself; and (2) damage to the epiphysis due to repetitive pathological fractures associated with SBC. In addressing this case, surgical intervention was undertaken to correct the proximal humerus varus deformity. This approach offered the advantages of simultaneously correcting angular abnormalities, achieving mild limb lengthening, providing definitive SBC treatment, and reducing the overall treatment duration.

CONCLUSION

As per current literature, acute correction of acute angular deformity in proximal humeral SBC is not well comprehended. However, in this specific case, acute correction was considered an optimal solution.

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.

Results of Allografts and Synthetic Grafts in Humeral Simple Bone Cysts

PURPOSE OF THE STUDY

Simple bone cysts (SBCs) are the most common benign bone lesions in childhood. There are many different methods in the treatment of SBCs. There is no consensus on which method to use in the treatment. In this study, we compared the results of allogeneic bone graft or synthetic bone graft in addition to fl exible intramedullary nail (FIN) for SBC located in the humerus.

MATERIAL AND METHODS

This retrospective study comparing the data of 19 (group 1: 8 curettage, allograft and FIN; group 2: 11 curettage, synthetic graft and FIN) patients with a mean age of 11.4 (6 to 26; seven female, twelve male) who were surgically treated in our hospital for humeral SBC between April 2014 and January 2020. Patient data included age, sex, anatomical side, stage of the cyst, pathological fracture, previous treatments and complications.

RESULTS

The mean follow-up period was 33.7 months (12 to 61). The average last follow-up Musculoskeletal Tumor Society functional scores for groups 1 and 2 were 27.8 (20 to 30) and 28.6 (21 to 30) (P > 0.05). Complete or signifi cant partial radiographic healing rates were achieved in group 1 (75%) compared with group 2 (81.9%). The reoperation rates for groups 1 and 2 were 62.5% (5/8; three for nails removed, two for recurrence) and 36.3% (4/11; two for nails removed, two for recurrence). One patient in group 2 had a 15° varus deformity due to recurrence. No other complications were observed.

CONCLUSIONS

The combination of curettage-grafonage FIN is a common treatment method in recent years, as it provides early cyst healing and limb mobilization in SBCs located in the upper extremity. For defects after curettage of the bone cysts, allogeneic or synthetic grafts (granule b-tricalcium phospate) which have similar results in terms of healing can be used as an alternative to each other.

KEY WORDS

allografts, bone cysts, bone nails, synthetic grafts, humerus.

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.

MR angiography facilitates the differentiation of aneurysmal from unicameral bone cysts

OBJECTIVES

The objective of this work was to evaluate the incremental value of MR angiography over plain radiographs and MRI for the differentiation of aneurysmal bone cysts (ABCs) from unicameral bone cysts (UBCs).

METHODS

Thirty-six juvenile patients with histologically secured primary ABCs or UBCs were included in this retrospective study. Two radiologists assessed all obtained images in a blinded fashion using a catalog of previously suggested imaging findings. A second readout with supplementary MR angiography images was performed after 8 weeks to prevent observer recall bias. Diagnostic accuracy parameters were calculated for individual imaging findings, and overall diagnostic accuracy and diagnostic confidence were assessed for all readouts. Receiver operating characteristic (ROC) curve comparison was used to determine the incremental value of MR angiography.

RESULTS

Of 16 imaging features, only abnormal vascularization in MR angiography provided sufficient diagnostic accuracy for the identification of ABCs. Other imaging features such as fluid-fluid levels and internal septations were insufficient for the differentiation of UBCs from ABCs. Availability of MR angiography images significantly increased diagnostic accuracy (94.4 vs 75.0% and 83.3 vs 69.4%, respectively, p < 0.05) and diagnostic confidence (4.5 vs 3.7, p < 0.05) of reading radiologists.

CONCLUSION

The presence of arterial feeders in MR angiography can accurately discriminate primary ABCs from UBCs and increases the diagnostic accuracy and diagnostic confidence of reporting radiologists.

ADVANCES IN KNOWLEDGE

Radiographic differentiation of cystic bone lesions such as ABCs and UBCs remains challenging. We demonstrate that MR angiography provides incremental value and suggest inclusion in standard examination protocols.

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

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

Current strategies for the treatment of solitary and aneurysmal bone cysts: A review of the literature

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SBCs can mostly be treated conservatively.

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In ABCs a biopsy is compulsory.

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ABCs can be treated by polidocanol instillations adequately.

This review of the literature aims to compare the etiology, the pathogenesis, the clinical diagnostics and the relevant treatment options of two different types of cystic bone lesions: the solitary bone cyst (SBC) and the aneurysmal bone cyst (ABC). Whereas the clinical symptoms and the radiographic appearance can be similar, the diagnostic pathway and the treatment options are clearly different.

The solitary bone cyst (SBC) represents a tumor-like bone lesion, occurring most frequently in the humerus and femur in children and adolescents. Pain caused by intercurrent pathological fractures is often the first symptom, and up to 87% of the cysts are associated with pathological fractures. In the majority of cases SBCs can be treated conservatively, especially in the upper extremity. However, if a fracture is completely dislocated, joint affecting, unstable or open, surgical treatment is necessary. Pain under weight bearing or regaining the ability to mobilize after fracture timely can necessitate surgical treatment in SBCs affecting the lower extremity. Spontaneous resolution can be seen in rare cases.

The aneurysmal bone cyst (ABC) is a benign, locally aggressive tumor that occurs in childhood and early adulthood. It usually affects the metaphysis of long bones but can also occur in the spine or the pelvis. ABC can be primary but also secondary to other bone pathologies. The diagnosis has to be confirmed by biopsy and histopathological examinations. With cytogenetic studies and the detection of specific translocations of the ubiquitin-specific protease (USP) 6 gene primary ABCs can be differentiated from secondary ABCs and other bone lesions. Among various modalities of treatment i.e. en bloc resection, intralesional curettage with adjuvants, embolization or the systemic application of denosumab, intralesional sclerotherapy using polidocanol is an effective and minimally invasive treatment of primary ABCs.

Comparative efficacy and safety profile for the treatment of humeral bone cysts in children: curettage and mixed bone grafting either with or without elastic intramedullary nailing

Purpose

The primary aim of our study was to evaluate the comparative efficacy and safety profile of curettage and mixed bone grafting without instrument or with elastic intramedullary nailing in the treatment of humeral bone cyst in children.

Methods

Our retrospective study included a total of 48 children harboring humeral bone cyst in our hospital from August 2012 to February 2019. The patients enrolled were divided into elastic nailing group with the application of elastic intramedullary nailing (n = 25) and control group without using instrument (n = 23) during the management of curettage and mixed bone grafting. The following medical outcomes of the two groups were monitored and recorded: the amount of intraoperative blood loss, operation time and postoperative full weight-bearing time, in addition to postoperative clinical effects after 1 year, the function and pain level of shoulder joint before and 1, 3, 6, 9, 12, and 16 months after operation. Follow-up radiographic outcomes were reviewed to observe bone healing, local recurrence and internal fixation loosening, and other postoperative complications.

Results

The clinical curative effect of the elastic nailing group was higher than that of the control group 16 months after operation (96.00% > 73.91%, P < 0.05). The intraoperative blood loss and postoperative full weight-bearing time in the elastic nailing group were less than those in the control group (P < 0.05), but the operation time was statistically insignificant between the two groups (P > 0.05). Before operation, the shoulder joint function of the two groups was comparable (P > 0.05), while the function showed remarkably better outcome in the elastic nailing group than control group 1 to 16 months after operation (P < 0.05). Before operation, the pain level of the two groups was comparable (P > 0.05), while 1 to 16 months after operation, the pain level of the elastic nailing group was significantly lower than that of the control group (P < 0.05). Patients in both groups were followed up for 16 months. Mixed bone grafting fusion was indicated by imaging CT and X-ray during the follow-up period, with an average fusion time of 11.3 ± 1.2 months (range, 8–16 months). Three months after operation, there was 1 case of incomplete pathological fracture in the control group, while no related complications occurred in the elastic nailing group. Moreover, no tumor recurrence was observed in the two groups. The two groups were comparable in terms of the incidence of complications (P > 0.05).

Conclusion

Children with humeral cyst treated with curettage and mixed bone grafting with the additional use of elastic intramedullary nailing exerted superior results to those without using instrument as there are beneficial outcomes and safety profile and no complications.

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.

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

Background

Simple bone cysts (SBCs) are common benign lytic bone lesions in children. This study focused on exploring a clinical treatment method, minimally invasive intramedullary decompression and drainage with elastic stable intramedullary nailing (ESIN) combined with intralesional injections of steroids, and evaluated its effectiveness, complications and morbidity through functional and radiographic outcomes.

Methods

The postoperative recovery of 18 children who suffered from SBCs of humerus was evaluated (mean follow-up, 40 months) from January 2009 to December 2016. These patients (11 males, 7 females; 8 in the left, 10 in the right; mean age, 10.9 years old) were treated with minimally invasive intramedullary decompression and drainage with ESIN combined with intralesional injections of steroids. The diagnosis was based on not only pre-operative typical medical images (X-rays/CT/MRI) but also surgical findings and pathological diagnosis. Radiological and functional outcomes were evaluated according to Capanna and Musculoskeletal Tumor Society (MSTS) score. The interclass differences were analyzed by t-test.

Results

According to Capanna and MSTS criteria, after treatment, 14 patients made full recoveries which was presented by all the cysts filled with bone tissue, and 4 patients made partially recoveries, which were presented by cystic spaces partially filled with low density bone. All the cysts responded to treatment method, and there was no cyst recurrence. All except 2 patients had good functional results. One of the two patients had irritation of the end of the nail and one patient had a valgus deformity.

Conclusions

Treatment for SBCs of humerus by minimally invasive intramedullary decompression and drainage with ESIN combined with intralesional injections of steroids is safe, effective and convenient. The clinical effect is satisfactory and worth popularizing.

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

BACKGROUND

A variety of treatment methods have so far been described for unicameral bone cysts (UBC). However, to the best of our knowledge, no particular consensus has yet been reached on when to operatively treat a patient with a humeral UBC. Therefore, members of the European Pediatric Orthopedic Society (EPOS) and Pediatric Orthopedic Society of North America (POSNA) were surveyed to characterize current treatment preferences.

METHODS

An online electronic questionnaire was sent out to all registered EPOS and POSNA members. The survey comprised 45 questions related to the diagnosis, treatment, and follow-up characteristics of patients with UBCs of the humerus. Particular questions related to the nonoperative or surgical treatment of pathologic proximal humerus and humeral shaft fractures were also included.

RESULTS

In total, 444 participants (132 EPOS and 292 POSNA members) responded, of whom 400 were actively involved in UBC treatment. The preferred diagnostic modalities to confirm the diagnosis of a UBC in the humerus were radiographs (88%), MRI in cases of questionable diagnosis (58%) or CT scan (8%). For painless UBCs 67% prefer no treatment at all except when the fracture risk is deemed high (then 53% recommend surgery); 71% of respondents would treat painful UBCs with surgery. Most common surgical techniques comprise curettage (45%), artificial bone substitutes (37%), corticosteroid injection (29%), or intramedullary stabilization (eg, rodding; 24%).Fractured, nondisplaced and mildly displaced proximal humerus UBCs and mildly displaced pathologic humerus shaft fractures are all preferably treated nonoperatively (94%, 91%, 83%, respectively). Severely displaced pathologic proximal humerus fractures are treated less often conservatively (36%) than surgically (40%), and severely displaced humerus shaft fractures are preferably treated surgically (63%) by intramedullary stabilization (60%).

CONCLUSIONS

There is great variation among EPOS and POSNA members with regards to the diagnosis and treatment of UBCs in the humerus. Although some consensus on general treatment principles is seen, specific surgical treatment indications vary.Prospective randomized-controlled studies are needed to evaluate the outcomes of the different surgical approaches compared with nonoperative strategies.

LEVEL OF EVIDENCE

Level V-expert opinion.

Comparison of curettage and bone grafting combined with elastic intramedullary nailing vs curettage and bone grafting in the treatment of long bone cysts in children

To compare the efficacy of curettage and bone grafting combined with elastic intramedullary nailing (EIN) vs curettage and bone grafting in the treatment of long bone cysts in children and to clarify the necessity of using EIN in the treatment of bone cysts.Sixty-two patients were involved in this study from Jan. 2009 to Sept. 2017 (43 males, 19 females; 27 humeri, 35 femurs); the patients were assigned to an EIN group, comprising 30 patients who underwent curettage and bone grafting combined with EIN, or to a non-elastic intramedullary nailing (NEIN) group, comprising 32 patients who underwent curettage and bone grafting alone. The prognosis of the 2 groups was assessed with reference to the standard of Capanna.No statistically significant differences in sex, age, location, activity, pathological fracture, cyst volume, operative time and intraoperative blood loss were found between the 2 groups (P > .05). The effective rate was 90.0% in the EIN group and 68.8% in the NEIN group, and the difference was statistically significant (P < .05).Compared to simple curettage and bone grafting, curettage and bone grafting combined with EIN treatment can significantly improve the prognosis of children with bone cysts. It is recommended that EIN be added to bone cyst curettage and bone grafting.

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.