Is it feasible and effective to provide faculty development programs online for clinical teachers? / 한국의학교육

Purpose@#Seoul National University College of Medicine operates a faculty development program for clinical teachers at multiple affiliated teaching hospitals. In 2020, the program was moved online due to coronavirus disease 2019. The purpose of this study was to determine whether it is feasible and effective to provide faculty development programs online in terms of clinical teachers’ participation and satisfaction in comparison with offline programs. @*Methods@#Clinical teachers participated in the clinical teaching methods programs offline in 2019 and online in 2020. We analyzed participation rate and satisfaction level. All surveys items were rated on a 5-point Likert scale. We also interviewed instructors about the advantages and drawbacks of the online program. @*Results@#The participation rate of the online program (89.5%) was significantly higher than that of the offline program (67.8%). The overall satisfaction level for the online program (4.37) was similar to that for the offline program (4.50). @*Conclusion@#Faculty development programs online are feasible and effective in medical education. We need to design training content that fits online programs, consider various online training methods to reinforce the strengths of online programs, and support participants to make good use of these programs.

Is it feasible and effective to provide faculty development programs online for clinical teachers? / 한국의학교육

Purpose@#Seoul National University College of Medicine operates a faculty development program for clinical teachers at multiple affiliated teaching hospitals. In 2020, the program was moved online due to coronavirus disease 2019. The purpose of this study was to determine whether it is feasible and effective to provide faculty development programs online in terms of clinical teachers’ participation and satisfaction in comparison with offline programs. @*Methods@#Clinical teachers participated in the clinical teaching methods programs offline in 2019 and online in 2020. We analyzed participation rate and satisfaction level. All surveys items were rated on a 5-point Likert scale. We also interviewed instructors about the advantages and drawbacks of the online program. @*Results@#The participation rate of the online program (89.5%) was significantly higher than that of the offline program (67.8%). The overall satisfaction level for the online program (4.37) was similar to that for the offline program (4.50). @*Conclusion@#Faculty development programs online are feasible and effective in medical education. We need to design training content that fits online programs, consider various online training methods to reinforce the strengths of online programs, and support participants to make good use of these programs.

Delta-like Factor 1 as a Possible Therapeutic Target for Sarcomas

Background@#Cancer stem cells (CSCs) are cells characterized by their self-renewal and tumorigenic potential. The purpose of this study was to discover the role of the delta-like factor 1 (DLK1) in sarcoma. @*Methods@#mRNA expression of DLK1 from 13 sarcoma cell lines was examined. Isolated CSCs from the tumors were examined using fluorescence-activated cell sorting (FACS) with CD133, the CSC marker, or sphere-forming assay. The relationship between DLK1 and CSCs in sarcoma was examined using cell proliferation and cell invasion assays after they were treated with DLK1 short interfering RNA (siRNA). @*Results@#A high expression of DLK1 mRNA was observed in all sarcoma cell lines. However, CSCs were isolated from over expressed sarcomas of the DLK1 gene, and they have shown to be expressed lower than the wild type. The anti-cancer effects of DLK1 siRNA inhibited cell proliferation and invasion in U2OS, A204, and sw872. In addition, treatment with DLK1 siRNA inhibited cell invasion in sw872 CSCs. DLK1 gene induces tumorigenesis in various sarcoma cells and regulates the invasiveness of liposarcoma. These results suggest that DLK1 could serve as a possible therapeutic target for sarcoma. @*Conclusions@#Our study showed that the DLK1 gene induces tumorigenesis in various sarcomas and is associated with invasive mechanism in sarcoma. These results suggest DLK1 could serve as a possible therapeutic target in a variety of sarcomas.

Factors Associated with Disease Stabilization of Desmoid-Type Fibromatosis

BACKGROUND: Spontaneous disease stabilization of desmoid-type fibromatosis (DF) has been demonstrated in many reports, and the watchful waiting approach without any frontline treatment is becoming popular as an initial management strategy. In this study, we aimed to assess the disease stabilization rate and identify predictive factors for disease stabilization of DF in patients with conservative treatment.METHODS: We reviewed 76 patients with sporadic extra-abdominal DF who were managed with frontline conservative treatment in our institute. The minimum follow-up was 12 months. Stabilization was defined as radiological evidence of no change or continuous decrease in size of the tumor for six months or more. The primary endpoint was stabilization of DF. Possible patient-, disease-, and treatment-related factors predictive of disease stabilization were analyzed with multivariate analysis.RESULTS: At final follow-up, 54 of the 76 tumors (71%) were stable, and mean time to stabilization was 30.4 months (range, 7 to 112 months). On Kaplan-Meier survival analysis, the spontaneous stabilization rate was 25.4% at one year, 52.7% at two years, and 70.9% at three years. The mean time to spontaneous stabilization was longer in patients with ≤ 40 years of age (p = 0.022) or recurrence (p = 0.041). On multivariate analysis with the Cox proportional hazard method, recurrence (hazard ratio [HR], 1.79; p = 0.041) and younger age (HR, 2.04; p = 0.022) were identified as independent prognostic factors for longer time to disease stabilization.CONCLUSIONS: Frontline conservative treatment seems to be the optimal treatment for most patients with DF. Younger patients or those with recurrence may require longer time to spontaneous disease stabilization.

Survival outcomes after adjuvant radiotherapy for aggressive fibromatosis depend on time frame and nuclear β-catenin

PURPOSE: To identify prognostic factors influencing progression-free survival (PFS) of aggressive fibromatosis (AF) after postoperative radiotherapy (PORT) and assess correlations between immunohistochemistry (IHC) features of β-catenin/smooth muscle actin (SMA) and PFS. MATERIALS AND METHODS: Records of 37 patients with AF treated by PORT from 1984 to 2015 were retrospectively reviewed. Fifteen patients underwent wide excision for AF and 22 patients received debulking operation. The median total dose of PORT was 59.4 Gy. IHC staining results of β-catenin and SMA were available for 11 and 12 patients, respectively. RESULTS: The median follow-up duration was 105.9 months. Five-year PFS rate was 70.9%. Tumor size or margin status was not related to PFS in univariate analysis (p = 0.197 and p = 0.716, respectively). Multivariate analysis showed that increased interval from surgery to PORT (>5.7 weeks) was a marginal risk factor for PFS (p = 0.054). Administration of PORT at the initial diagnosis resulted in significantly improved PFS compared to deferring PORT after recurrence (p = 0.045). Patient with both risk factors of deferring PORT after recurrence and interval from surgery to PORT >5.7 weeks had significantly lower 5-year PFS than patients without risk factor (34.1% vs. 100.0%; p = 0.012). Nuclear β-catenin intensity tended to inversely correlate with 5-year PFS, although it did not reach statistical significance (62.5% at low vs. 100.0% at high; p = 0.260). SMA intensity was not related to PFS (p = 0.700). CONCLUSION: PORT should be performed immediately after surgery irrespective of margin status or tumor size especially in recurrent case. Nuclear β-catenin staining intensity of IHC might correlate with local recurrence.

Role of Nonsteroidal Anti-inflammatory Drug in Treatment of Extra-abdominal Desmoid Tumors

BACKGROUND: We retrospectively reviewed the outcomes of patients who had been treated with meloxicam for the extra-abdominal desmoid tumors and evaluated the correlation between clinical outcome and clinic pathological variables. METHODS: Twenty patients treated with meloxicam were followed up every 3 to 6 months. Meloxicam administration was planned at 15 mg/day orally for 6 months. RESULTS: Of the 20 patients evaluated, according to Response Evaluation Criteria in Solid Tumors criteria, there were five patients with partial response (25.0%), eight with stable disease (40.0%), and seven with tumor progression (35.0%). The cumulative probability of dropping out from our nonsurgical strategy using meloxicam was 35.0% at 1 year and 35.0% at 5 years. CONCLUSIONS: The present study suggests that conservative treatment would be a primary treatment option for this perplexing disease even though we were not able to determine that the use of a cyclooxygenase-2 inhibitor would have an additional influence on the natural course of a desmoid tumor.

Role of CD74 and Its Relationship with Macrophage Migration Inhibitory Factor in Osteosarcoma Tumorigenesis / 대한정형외과학회잡지

PURPOSE: CD74 (cluster of differentiation 74) is a type II transmembrane protein that associates with MHC-II (major histocompatibility complex-II) molecules and binds with the macrophage migration inhibitory factor (MIF), which is known to be associated with tumorigenesis. The purpose of this study was to examine the relationship between CD74 with MIF and the role of CD74 in osteosarcoma tumorigenesis. MATERIALS AND METHODS: A correlation between CD74 with MIF was examined using immunohistochemistry (IHC) of tissues from patients with osteosarcoma (n=45). The mRNA expression of CD74 from patient-derived primary cells of osteosarcoma (n=22) was examined by a real-time polymerase chain reaction. The role of CD74 and in cisplatin-resistance of osteosarcoma was examined using WST-1 and colony forming assay. RESULTS: Of the 45 patients, 25 patients (55.6%) had a high level of expression in both CD74 and MIF by IHC. High level of MIF expression was observed in 40 patients (88.9%). We detected that mRNA expression of CD74 was higher in cells of all osteosarcoma patients (n=22) examined than in the control cells (hFOb 1.19). After cisplatin treatment, the inhibition of cell proliferation and suppression of colony formation were reduced in osteosarcoma cells expressing CD74. Interestingly, the effect of inhibiting anchorage independent growth was activated after cisplatin treatment in the cells with very high expression CD74 mRNA. CONCLUSION: This study suggests that the level of CD74 expression correlates with that of MIF expression. Moreover, CD74 might have a role in cisplatin resistance of osteosarcoma.

Secondary Chondrosarcoma from an Osteochondroma of the Proximal Tibia Involving the Fibula

There are few reports on the surgical treatment of secondary malignancy arising from an osteochondroma on the lateral side of the proximal tibia. From March 2008 to December 2011, 3 patients were treated for a secondary chondrosarcoma from an osteochondroma of the proximal tibia involving the fibula. The operative procedure can be summed up as follows: (1) resection of the tumor including the fibula; (2) preservation of the peroneal nerve and the fibular head; and (3) arthrodesis of the proximal tibiofibular joint. Serial radiological studies showed successful fusion in the proximal tibiofibular joint in all patients. The Musculoskeletal Tumor Society functional scores were excellent in all 3 patients. No patients showed instability of the ipsilateral knee joint in any direction. All 3 patients could return to sports activities. Until the last follow-up, there was no evidence of disease recurrence. We suggest that the operative procedure described in this article would provide satisfactory oncological and functional outcomes.

Outcome after Surgery for Metastases to the Pelvic Bone: A Single Institutional Experience

BACKGROUND: The pelvic bone is the most common site of bone metastases following the axial skeleton. Surgery on the pelvic bone is a demanding procedure. Few studies have been published on the surgical outcomes of metastasis to the pelvic bone with only small numbers of patients involved. This study sought to analyze the complications, local progression and survival after surgery for metastasis to the pelvic bone on a larger cohort of patients. METHODS: We analyzed 83 patients who underwent surgery for metastases to the pelvic bone between the years 2000 and 2015. There were 41 men and 42 women with a mean age of 55 years. Possible factors that might be associated with complications, local progression and survival were investigated with regard to patient demographics and disease-related and treatment-related variables. RESULTS: The overall complication rate was 16% (13/83). Advanced age (> 55 years, p = 0.034) and low preoperative serum albumin levels (≤ 39 g/L, p = 0.001) were associated with increased complication rates. In patients with periacetabular disease, the complication rate was higher in those who underwent total hip replacement arthroplasty (THR) than those who did not (p = 0.030). Local progression rate was 46% (37/83). The overall median time to local progression was 26 ± 14.3 months. The median time from local progression to death was 13 months (range, 0 to 81 months). The local progression-free survival was 52.6% ± 6.4% at 2 years and 36.4%± 7.6% at 5 years, respectively. Presence of skip lesions (p = 0.017) and presence of visceral metastasis (p = 0.027) were found to be significantly associated with local progression. The median survival of all patients was 24 months. The 2-year and 3-year survival rates were 52.5% ± 5.9% and 35.6% ± 6%, respectively. Metastasis from the kidney, breast, or thyroid or of hematolymphoid origin (p = 0.014), absence of visceral metastasis (p = 0.017) and higher preoperative serum albumin levels (p = 0.009) were associated with a prolonged survival. CONCLUSIONS: Advanced age and low serum albumin levels were associated with high complication rates. Local progression after surgery for metastases to the pelvic bone was affected by the presence of skip lesions, not by surgical margins. Primary cancer type, serum albumin level and visceral metastasis influenced survival.

Intramedullary Nailing for Pathological Fractures of the Proximal Humerus

BACKGROUND: Endoprosthetic reconstruction is widely applied for pathological fractures of the proximal humerus; however, functional impairment is usually unsatisfactory. The aims of the current study are to evaluate the reliability of interlocking intramedullary (IM) nailing with cement augmentation as a fixation method in proximal humeral lesions and to assess functional outcomes. METHODS: We reviewed 32 patients with pathological fractures of the proximal humerus who underwent interlocking IM nailing and cement augmentation. Functional scores and pain relief were assessed as outcomes. RESULTS: The mean follow-up period was 14.2 months. The mean Musculoskeletal Tumor Society functional score and Karnofsky performance status scale score were 27.7 and 75.6, respectively. Improvement of pain assessed using the visual analogue scale was 6.2 on average. Thirty-one patients (97%) experienced no pain after surgery. The mean ranges of forward flexion and abduction were 115° and 112.6°, respectively. All patients achieved stability and had no local recurrence without failure of fixation until the last follow-up. CONCLUSIONS: Proximal interlocking IM nailing with cement augmentation appears to be a reliable treatment option for pathological or impending fractures of the proximal humerus in selected patients with metastatic tumors, even with extensive bone destruction.

Radiation-Induced Sarcoma: A 15-Year Experience in a Single Large Tertiary Referral Center / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study is to report on the incidence and the experience in management of radiation-induced sarcoma (RIS) at a large single center in Korea for 15 years. MATERIALS AND METHODS: We retrospectively reviewed the sarcoma registry of a large institution from January 2000 to April 2014. RESULTS: Out of the 3,674 patients listed in the registry, 33 patients (0.9%) diagnosed with RIS were identified. The median latency of RIS was 12.1 years. The number of cases of RIS increased from four cases in the years 2000-2003 to 14 cases in the years 2012-2014. The most common histology was osteosarcoma (36.4%). The median follow-up period was 23.1 months, the median overall survival (OS) of all patients was 2.9 years, and their 5-year survival rate was 44.7%. Univariate and multivariate analyses showed association of the age at diagnosis (p=0.01) and the treatment aim (p=0.001) with the OS. The median OS and the 5-year survival rate of patients treated with curative surgery (n=19) were 9.6 years and 65%, respectively, and of the conservatively treated patients, 0.7 years and 0% (n=14). Re-irradiation was delivered to nine patients, and radiation toxicity was observed in five patients. CONCLUSION: In this study, RIS accounted for 0.9% of the cases of sarcoma, with increasing incidence. Despite the association of curative resection with increased survival, it could be applied to only 58% of the patients. Considering the limited treatment options for RIS, conduct of a genetic study to identify the underlying mechanism of RIS is needed.

Incidence and Treatment Pattern of Extremity Soft Tissue Sarcoma in Korea, 2009-2011: A Nationwide Study Based on the Health Insurance Review and Assessment Service Database / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: We conducted a nationwide study to assess the incidence and treatment patterns of extremity soft tissue sarcoma (STS) in South Korea. MATERIALS AND METHODS: The nationwide incidence and treatment patterns of extremity STS were assessed using two nationwide databases, the Korea National Cancer Incidence (KNCI) database and the Health Insurance Review and Assessment Service (HIRA) database. RESULTS: A total of 1,236 patients were newly diagnosed with extremity STS during the 3-year study period, from 2009 to 2011. The annual incidence of extremity STS in the Korean population was approximately 0.9 per 100,000 people with a male bias that increased with age and was especially pronounced amongst individuals aged > 80 years. Approximately 7% of patients did not receive any treatment, and surgical excision was performed for 85% of those who were treated. CONCLUSION: This is the first nationwide study of the incidence and treatment patterns of extremity STS in Korea using two national databases (KNCI and HIRA), which include the entire Korean population. The results of this study may be useful for future planning and management of STS, at the national level.

Distinct Clinical Characteristics of Unplanned Excision in Synovial Sarcoma

BACKGROUND: We aimed to describe the clinical characteristics and outcomes of unplanned excisions of synovial sarcomas. METHODS: In total, 90 patients with synovial sarcomas in the extremities were retrospectively reviewed. Patients were divided into unplanned excision (n = 38) and planned excision (n = 52) groups. The average follow-up period was 6 years. The clinicopathological characteristics and oncologic outcomes were compared. RESULTS: The unplanned excision group showed longer duration of symptoms before diagnosis (p = 0.023), smaller lesion dimensions (p = 0.001), superficial location (p = 0.049), and predilection in the upper extremities (p = 0.037). Synovial sarcomas were most commonly misdiagnosed as neurogenic tumors (56%) in the upper extremities or as cystic masses (47%) in the lower extremities. Oncological outcomes, including disease-specific survival, metastasis-free survival, or local recurrence were not significantly different between the 2 groups (p = 0.159, p = 0.444, and p = 0.335, respectively). Repeated unplanned excision (p = 0.012) and delayed re-excision (p = 0.038) were significant risk factors for local recurrence in the unplanned excision group. CONCLUSIONS: Synovial sarcomas treated with unplanned excision had distinct characteristics. These findings are important for developing diagnostic and therapeutic strategies for synovial sarcoma.

Long-term Outcome of Chondrosarcoma: A Single Institutional Experience / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The prognostic factors of chondrosarcoma remain uncertain as only a few large studies with long-term follow-up have been reported. The aim of this study was to analyze oncological outcomes and prognostic factors. MATERIALS AND METHODS: A retrospective review of oncological outcomes and prognostic factors was performed on 125 consecutive chondrosarcoma patients who underwent surgery at our institution. RESULTS: Overall survival was 91.6%+/-2.5%, 84.1%+/-3.8%, and 84.1%+/-3.8% at 5, 10, and 15 years respectively. Among the histological types, dedifferentiated type showed the worst survival (p < 0.001). As for conventional type chondrosarcoma, histologic grade and anatomical location predicted outcome, with high-grade with axial location having the worst outcome (p < 0.001). In contrast, low-grade chondrosarcoma of appendicular skeleton could be treated safely by intralesional curettage. CONCLUSION: Histological type was significantly associated with the outcome of chondrosarcoma. For the conventional type, histologic grade and anatomical location predicted outcome, with high-grade with axial location having the worst outcome.

Comorbidity is Independently Associated with Poor Outcome in Extremity Soft Tissue Sarcoma

BACKGROUND: Comorbidity has not been examined as an independent prognostic factor in soft tissue sarcoma (STS). We examined the prognostic impact of comorbidity on oncologic outcome in STS with an adjustment for possible confounding factors. METHODS: A retrospective review was performed on 349 patients who had undergone surgery for high-grade localized STS of extremity at our institute. Conditions known to alter the risk of mortality, as defined in the Charlson comorbidity index, were classified as comorbidities and 43 patients (12%) had at least one comorbidity at the time of surgery. The association of comorbidity and oncologic outcomes of local recurrence-free survival (LRFS) and disease-specific survival (DSS) were tested with adjustment for confounding factors. RESULTS: Comorbidity was associated with old age, high tumor grade, and large tumor size. The presence of comorbidity was independently associated with poor LRFS and DSS, even after adjusting for confounding factors including age and treatment variables. CONCLUSIONS: Our data suggest that the presence of comorbidity is an independent prognostic factor for extremity STS.

Common Benign Bone Tumors in Clinic / 대한정형외과학회잡지

Benign bone tumors can be found in the following clinical situations: 1) incidental findings on chest radiograph for health screening without symptoms or radiographs after traffic accident; 2) radiographs for other orthopedic problems, such as osteoarthritis; and 3) pain caused by the tumor. Knowledge of various diseases and their clinical characteristics is required for diagnosis of benign bone tumors. In addition, one should consider carefully whether or not the lesion has the characteristics of benign bone tumor or possibility of malignancy so that proper treatment can be decided. In case the diagnosis cannot be confirmed, even though benign bone tumor is suspected on radiography, follow-up radiographs should be taken to rule-out malignant bone tumors.

The Role of CTGF in Osteosarcoma Progression / 대한골관절종양학회지

PURPOSE: To examine the expression of Connective Tissue Growth Factor (CTGF) in osteosarcoma and to evaluate its role in osteosarcoma invasion and proliferation. MATERIALS AND METHODS: The mRNA expression of CTGF from 23 patient-derived osteosarcoma cell lines was examined, and the role of CTGF in cell invasion and proliferation was examined using siRNA transfection. RESULTS: The over-expression of CTGF mRNA was observed in 17 cell lines (74%). CTGF-specific siRNA transfection into SaOS-2 and MG63 cell lines resulted in efficient knockdown of CTGF expression on Western blot analysis. siRNA transfected cells showed decreased migration on Matrigel invasion assay and decreased cell proliferation on WST-1 assay. CONCLUSION: These results indicated that the CTGF expression may play an important role in osteosarcoma progression, and may be a therapeutic target of osteosarcoma.

Non-Spine Bone Metastasis as an Initial Manifestation of Cancer in Korea

Non-spine bone metastasis accounts for approximately 20% of all skeletal metastases, but little data have been published that focused on bone metastasis to the pelvis and extremities as an initial manifestation of cancer. We determined 1) clinicopathologic characteristics of patients who presented with non-spine bone metastasis of unknown primary malignancy, and 2) process by which the diagnosis of primary cancer was made. We retrospectively reviewed 84 patients with bone metastasis of unknown primary cancer site at the time of presentation. The study population consisted of 56 men and 28 women, with a mean age of 59.1 yr (17.5-85.6 yr). The average follow-up period was 20.8 months (1-120 mo). Primary cancer site was identified in 79 patients (94.0%), and was determined to be the lung (46.4%), kidney (13.1%), liver (9.5%), thyroid (8.3%), and prostate (4.8%). Five-year overall survival rate was 28.0%. Multiple bone metastases, distant organ metastasis, and multiple bone with organ metastases were the significant prognostic factors in univariate analysis. Multiple bone metastases remained significant after multivariate analysis (P = 0.008). Lung cancer is the most common site of primary cancer, and patients with multiple bone metastases have a poor prognosis, possibly due to disseminated cancer and a greater tumor burden.

Navigation-Assisted Orthopedic Surgery in Bone Tumor / 대한정형외과학회잡지

The usefulness and accuracy of computer-assisted surgery have been evaluated clinically in many orthopedic fields, including joint replacement arthroplasty, pedicle screw placement, and cruciate ligament reconstruction of the knee joint. Since several preliminary reports on application of navigation to bone tumor resection and reconstruction surgery have recently been issued, navigation-assisted surgery for bone tumors has received significant attention with regard to its usefulness. In particular, navigation can be helpful during surgery for musculoskeletal tumors, because it can maximize the accuracy of resection and minimize the unnecessary sacrifice of normal tissue by providing precise intraoperative three-dimensional radiological information. In addition, it is helpful in prosthetic reconstruction, because preoperative virtual simulation makes it possible to estimate size and location of bone defect to be left after tumor resection. Surgeons should recognize that use of navigation systems in bone tumor surgery has some hidden pitfalls. Here, based on our clinical results, we describe the surgical techniques that we have used and include some cautionary notes.

Intercalary Allograft Reconstruction after Malignant Tumor Resection around the Knee / 대한정형외과학회잡지

PURPOSE: We aimed to assess the treatment outcomes and factors affecting bone union of intercalary allograft reconstruction after primary malignant bone tumor resection around the knee. MATERIALS AND METHODS: Twenty-one patients who underwent intercalary allograft reconstruction after resection of a malignant tumor of femur or tibia were retrospectively reviewed. The average follow-up period was 46.4 months. Location of the tumor was as follows: femur in 12 cases and tibia in 9. Osteosarcoma was the most common tumor (12 cases). Intercalary allograft was internally fixed with an intramedullary (IM) nail in 3 cases, with a plate in 12 cases and with an IM nail combined with a plate in 6 cases. The survival of the grafts and functional outcomes were evaluated. Factors affecting bone union and complications were assessed. RESULTS: All allografts survived without removal. The average Musculoskeletal Tumor Society functional score was 27. The mean length of the allograft was 16.7 cm and bony union took 10.9 months, in average. Nonunion occurred in 6 cases: at the diaphyseal side in 3, and the remaining 3 at the metaphyseal side. The graft length was shorter than average in all the diaphyseal side nonunion cases and longer than average in all the metaphyseal side nonunion cases. All cases of nonunion obtained bone union after additional operations (autologous bone graft alone: 1, bone graft with hardware change: 5). CONCLUSION: Survival and functional outcomes of intercalary allograft were satisfactory. Long allograft showed a tendency of fracture or nonunion at the metaphyseal side. Nonunion could be managed with additional operation without allograft removal.