Long-term outcomes after an initial experience of computer-navigated resection of primary pelvic and sacral bone tumours: soft-tissue margins must be adequate to reduce local recurrences.

AIMS: The aim of this study was to investigate the local recurrence rate at an extended follow-up in patients following navigated resection of primary pelvic and sacral tumours. PATIENTS AND METHODS: This prospective cohort study comprised 23 consecutive patients (nine female, 14 male) who underwent resection of a primary pelvic or sacral tumour, using computer navigation, between 2010 and 2012. The mean age of the patients at the time of presentation was 51 years (10 to 77). The rates of local recurrence and mortality were calculated using the Kaplan-Meier method. RESULTS: Bone resection margins were all clear and there were no bony recurrences. At a mean follow-up for all patients of 59 months (12 to 93), eight patients (34.8%) developed soft-tissue local recurrence, with a cumulative rate of local recurrence at six-years of 35.1% (95% confidence interval (CI) 19.3 to 58.1). The cumulative all-cause rate of mortality at six-years was 26.1% (95% CI 12.7 to 49.1). CONCLUSION: Despite the positive early experience with navigated-assisted resection, local recurrence rates remain high. With increasing knowledge of the size of soft-tissue margins required to reduce local recurrence and the close proximity of native structures in the pelvis, we advise against compromising resection to preserve function, and encourage surgeons to reduce local recurrence by prioritizing wide resection margins of the tumour. Cite this article: Bone Joint J 2019;101-B:484-490.

Author Correction: Chemotherapy with radiotherapy influences time-to-development of radiation-induced sarcomas: a multicenter study.

Since the publication of this paper, the authors noticed an error in Fig. 1. The X-axis on all the figure panels should read 'Time (years)', not 'Time (months)'. The corrected Fig. 1 is shown below.

Longer duration of symptoms at the time of presentation is not associated with worse survival in primary bone sarcoma.

Aims: The primary aim of this study was to determine the effect of the duration of symptoms (DOS) prior to diagnosis on the overall survival in patients with a primary bone sarcoma. Patients and Methods: In a retrospective analysis of a sarcoma database at a single institution between 1990 and 2014, we identified 1446 patients with non-metastatic and 346 with metastatic bone sarcoma. Low-grade types of tumour were excluded. Our data included the demographics of the patients, the characteristics of the tumour, and the survival outcome of patients. Cox proportional hazards analysis and Kaplan-Meier survival analysis were performed, and the survivorship of the non-metastatic and metastatic cohorts were compared. Results: In the non-metastatic cohort, a longer DOS was associated with a slightly more favourable survival (hazard ratio (HR) 0.996, 95% confidence interval (CI) 0.994 to 0.998, p < 0.001). In all types of tumour, there was no difference in survival between patients with a DOS of greater than four months and those with a DOS of less than four months (p = 0.566). There was no correlation between the year of diagnosis and survival (p = 0.741). A diagnosis of chondrosarcoma (HR 0.636, 95% CI 0.474 to 0.854, p = 0.003) had the strongest positive effect on survival, while location in the axial skeleton (HR 1.76, 95% CI 1.36 to 2.29, p < 0.001) had the strongest negative effect on survival. Larger size of tumour (HR 1.05, 95% CI 1.03 to 1.06, p < 0.001) and increased age of the patient (HR 1.02, 95% CI 1.01 to 1.03, p < 0.001) had a slightly negative effect on survival. Metastatic and non-metastatic cohorts had similar median DOS (16 weeks, p = 0.277), although the median survival (15.5 months vs 41 months) and rates of survival at one year (69% vs 89%) and five years (20% vs 59%) were significantly shorter in the metastatic cohort. Conclusion: A longer DOS prior to diagnosis is not associated with a poorer overall survival in patients with a primary bone sarcoma. Location in the axial skeleton remains the strongest predictor of a worse prognosis. This may be helpful in counselling patients referred for evaluation on a delayed basis. Cite this article: Bone Joint J 2018;100-B:652-61.

The role of grade in local recurrence and the disease-specific survival in chondrosarcomas.

Aims: The purpose of this study was to describe the effect of histological grade on disease-specific survival in patients with chondrosarcoma. Patients and Methods: A total of 343 patients with a chondrosarcoma were included. The histological grade was assessed on the initial biopsy and on the resection specimen. Where the histology showed a mixed grade, the highest grade was taken as the definitive grade. When only small focal areas showed higher grade, the final grade was considered as both. Results: The concordance between the highest preoperative biopsy grading and the highest final grading of the resection specimen in total was only 43% (146/343). In 102 specimens (30%), a small number of cells or focal areas of higher grade were observed in contrast to the main histology. The disease-specific survival, stratified according to the predominant histological grade, showed greater variation than when stratified according to the highest grade seen in the resection specimen. Conclusion: The diagnostic biopsy in chondrosarcoma is unreliable in assessing the definitive grade and the malignant potential of the tumour. When categorizing the grade of the resection specimen, the prognosis for local recurrence and disease-specific survival should be based on the highest grade seen, even when seen in only a few cells. Cite this article: Bone Joint J 2018;100-B:662-6.

The use of a non-invasive extendable prosthesis at the time of revision arthroplasty.

Aims: The use of a noninvasive growing endoprosthesis in the management of primary bone tumours in children is well established. However, the efficacy of such a prosthesis in those requiring a revision procedure has yet to be established. The aim of this series was to present our results using extendable prostheses for the revision of previous endoprostheses. Patients and Methods: All patients who had a noninvasive growing endoprosthesis inserted at the time of a revision procedure were identified from our database. A total of 21 patients (seven female patients, 14 male) with a mean age of 20.4 years (10 to 41) at the time of revision were included. The indications for revision were mechanical failure, trauma or infection with a residual leg-length discrepancy. The mean follow-up was 70 months (17 to 128). The mean shortening prior to revision was 44 mm (10 to 100). Lengthening was performed in all but one patient with a mean lengthening of 51 mm (5 to 140). Results: The mean residual leg length discrepancy at final follow-up of 15 mm (1 to 35). Two patients developed a deep periprosthetic infection, of whom one required amputation to eradicate the infection; the other required two-stage revision. Implant survival according to Henderson criteria was 86% at two years and 72% at five years. When considering revision for any cause (including revision of the growing prosthesis to a non-growing prosthesis), revision-free implant survival was 75% at two years, but reduced to 55% at five years. Conclusion: Our experience indicates that revision surgery using a noninvasive growing endoprosthesis is a successful option for improving leg length discrepancy and should be considered in patients with significant leg-length discrepancy requiring a revision procedure. Cite this article: Bone Joint J 2018;100-B:370-7.

Risk analysis factors for local recurrence in Ewing's sarcoma: when should adjuvant radiotherapy be administered?

AIMS: The aim of this study was to analyse a group of patients with non-metastatic Ewing's sarcoma at presentation and identify prognostic factors affecting the development of local recurrence, in order to assess the role of radiotherapy. PATIENTS AND METHODS: A retrospective review of all patients with a Ewing's sarcoma treated between 1980 and 2012 was carried out. Only those treated with chemotherapy followed by surgery and/or radiotherapy were included. Patients were grouped according to site (central or limb) for further analysis of the prognostic factors. RESULTS: A total of 388 patients were included in the study. Of these, 60 (15%) developed local recurrence at a mean median of 27 months (sd 24, range 7 to 150) and the five-year local recurrence-free survival (5yrLRFS) was 83%. For central tumours, the size of the tumour and histological response to chemotherapy were found to be significant factors for local recurrence. For limb tumours, local recurrence was affected by intralesional and marginal resections, but not by the histological response to chemotherapy. Radiotherapy in those with a marginal resection reduced the risk of local recurrence (5yrLRFS: 96% versus 81%, p = 0.044). CONCLUSION: Local recurrence significantly affects the overall survival in patients with a Ewing's sarcoma. For those with a tumour in a limb, radiotherapy reduced the risk of local recurrence, especially in those with a marginal margin of excision, but the effect in central tumours was less clear. Radiotherapy for those who have had a wide margin of resection does not reduce the risk of local recurrence, regardless of the histological response to chemotherapy. Cite this article: Bone Joint J 2018;100-B: 247-55.

Impact of specialist management on survival from radiation-associated angiosarcoma of the breast.

BACKGROUND: Radiation-associated angiosarcoma of the breast (RAAS) is a rare complication of adjuvant radiotherapy associated with poor survival. The British Sarcoma Group guidelines recommend that all angiosarcomas are referred to a sarcoma multidisciplinary team, although there is no recommendation that patients are managed within a sarcoma service. The aims of this study were to compare survival, complete excision rates and local recurrence rates of patients managed within a sarcoma service and those managed within local hospitals. METHODS: All patients with RAAS referred to a regional sarcoma service between 1998 and 2015 were identified from prospective databases. Patient records, and radiology, pathology and operation notes were reviewed retrospectively. RESULTS: Thirty-six patients were operated on with curative intent; 26 were managed by the sarcoma service (of whom 21 underwent radical excision of the irradiated field followed by chest wall reconstruction) and ten were managed locally. Median age was 69·5 (range 43-85) years. Disease-specific survival was significantly longer in patients managed by the sarcoma service than in those managed locally: median 91·1 (range 69·2-113·0) versus 48·8 (18·6-79·1) months respectively (P = 0·012). Overall survival rates were similar (P = 0·112). There was no difference in complete excision rate (18 of 26 in sarcoma service versus 5 of 10 in local services; P = 0·456), although the local recurrence rate was significantly lower among patients managed by the sarcoma service (9 of 26 versus 8 of 10; P = 0·015). CONCLUSION: Specialist management of RAAS leads to fewer local recurrences and improved disease-specific survival. Early referral and management within specialist units is recommended.

Malignant bone tumours of the foot.

Introduction Malignant osseous foot tumours are uncommon. Their oncological outcomes have been poorly documented in the literature so far. The aim of this study was to establish the incidence and to evaluate the oncological outcomes of such patients. Methods Our large orthopaedic oncology database was used to review 70 malignant osseous foot tumour patients. Results The age at diagnosis of malignant osseous foot tumours demonstrated a bimodal distribution peaking in the second and eighth decades of life. Overall, 55 primary malignant bone tumours of the foot (79%) were identified. The median duration from onset of symptoms to diagnosis was 52 weeks (interquartile range [IQR]: 17-104). Eight primary tumours (15%) underwent an accidental excision (ie intralesional excision of a malignant bone tumour where some of the tumour has been left behind, also known as a 'whoops procedure') prior to referral to our unit. Forty-six patients (84%) underwent surgery overall and thirteen of these developed recurrence or metastases. Seven of eight patients with a previous accidental excision underwent amputation. Fifteen osseous metastatic foot lesions were identified. The median length of foot symptoms to diagnosis was 24 weeks (IQR: 20-36 weeks). The median time to death following diagnosis of osseous foot metastases was 20.1 months (IQR: 11.3-27.8 months). Conclusions A high index of suspicion and awareness of clinical features of malignant osseous foot tumours are both essential to avoid diagnostic delays. Amputation is associated with a respectable outcome for patients who have undergone previous accidental excisions.

Bone metastases of the hand.

Introduction The aim of this study was to identify patients with malignant hand lesions, establish the proportions of those that were metastases and review their clinical course. Methods A retrospective search of a prospective tumour database was carried out to identify all patients treated at our unit with hand metastases. Patient demographics were recorded including site of primary malignancy, region of the hand involved, management of their metastasis and clinical outcome. Results Overall, 149 patients were identified with a malignant tumour of the hand. Ten had a metastatic lesion. There were 3 women and 7 men with a median age of 68 years (range: 28-91 years) at presentation. All presented with non-mechanical hand pain while four had pain and swelling. The median interval from symptom onset to diagnosis was eight weeks. The minimum follow-up duration was four months. Three patients had no history of malignancy. Of the remaining seven patients, three had other known metastases. Six patients underwent solely palliative radiotherapy. Three patients had amputation. One was treated with surgical excision and radiotherapy. One had an amputation and axillary node clearance. All but one patient had died by the time of the latest follow-up appointment. The median time to death following identification of acrometastases was 18 months. Sites of primary disease were skin (n=4), lung (n=3), kidney (n=2) and neuroendocrine system (n=1). The thumb was the most commonly affected location. Conclusions This study demonstrates that patients presenting with non-mechanical hand pain should be considered to have a malignant process until proved otherwise, particularly in patients with thumb symptoms and a history of prior malignancy.

Epithelioid sarcomas: How important is loco-regional control?

AIMS: To investigate the impact of the method of treatment on the oncological outcomes in patients with epithelioid sarcomas managed at two international speciality sarcoma centres. METHODS: The databases of two centres were used to identify patients treated for epithelioid sarcomas between 1985 and 2012. Patient, tumor, treatment and outcome data was collected. RESULTS: There were 36 males and 18 females with a mean age of 38.3 years (range 9-79). Of 49 patients who were treated surgically, limb salvage surgery was carried out in 38 patients (78%) and limb amputation in 11 (22%). Of 49 total patients who underwent surgery for ES, 48 (98%) with ES had negative margin resection and 24 (49%) received (neo) adjuvant radiotherapy. Regional lymph node metastases developed in 5 (13%) patients. The five-year risk of local recurrence was 14%. The overall survival rate at five and ten years was 70% and 66% respectively. In multivariate analysis of patients with localized disease and negative margins, survival and risk of metastases was worse in those treated by amputation. CONCLUSION: This series has shown that although the rate of local recurrence is not influenced by the type of surgery, the risk of metastases is higher following amputation. This finding is likely due to patients with larger, deeper and more locally advanced tumors requiring amputation. However, we could not prove that immediate amputation was likely to affect overall survival.

Reconstruction of the distal tibia following resection of aggressive bone tumours using a custom-made megaprosthesis.

OBJECTIVE: Largest, single-centre study of clinical and functional outcomes of patients who underwent endoprosthetic replacement (EPR) for aggressive distal tibial bone tumours. METHOD: Retrospective observational study of eight patients was undertaken. RESULTS: Median follow-up was 77 months (range 13-276). Cumulative five and ten year survival was 63% and 42% respectively. Three patients developed either disease recurrence or metastases post-surgery. One patient developed deep infection requiring washout and suppressive antibiotics. No patients required revision surgery. The median MSTS score at last follow up was 66%. CONCLUSIONS: EPR of the distal tibia is a viable option and provides good function outcomes.

Chemotherapy with radiotherapy influences time-to-development of radiation-induced sarcomas: a multicenter study.

BACKGROUND: An increasing number and proportion of cancer patients with apparently localised disease are treated with chemotherapy and radiation therapy in contemporary oncology practice. In a pilot study of radiation-induced sarcoma (RIS) patients, we demonstrated that chemotherapy was associated with a reduced time to development of RIS. We now present a multi-centre collaborative study to validate this association. METHODS: This was a retrospective cohort study of RIS cases across five large international sarcoma centres between 1 January 2000 to 31 December 2014. The primary endpoint was time to development of RIS. RESULTS: We identified 419 patients with RIS. Chemotherapy for the first malignancy was associated with a shorter time to RIS development (HR 1.37; 95% CI: 1.08-1.72; P=0.009). In the multi-variable model, older age (HR 2.11; 95% CI 1.83-2.43; P<0.001) and chemotherapy for the first malignancy (HR 1.61; 95% CI 1.26-2.05; P<0·001) were independently associated with a shorter time to RIS. Anthracyclines and alkylating agents significantly contribute to the effect. CONCLUSIONS: This study confirms an association between chemotherapy given for the first malignancy and a shorter time to development of RIS.

Resection of the ilium in patients with a sarcoma: should the pelvic ring be reconstructed?

AIMS: The aim of the study was to investigate the controversial issue of whether the pelvic ring should be reconstructed following resection of the sarcomas of the ilium. PATIENTS AND METHODS: From our database, we identified 64 patients who underwent excision of a tumour involving the ilium between 1976 and 2015. A total of 35 underwent complete resection, of whom 24 were reconstructed with a non-vascularised fibula graft, and four with extracorporeal irradiation and reimplantation. A total of 29 patients had a partial resection. The mean follow-up was 9.2 years (1.1 to 25.6). Functional outcomes were assessed using the Toronto Extremity Salvation Score (TESS) at final follow-up. In all, 32 patients (50%) had a chondrosarcoma. RESULTS: The mean TESS for all patients was 71.6% (17% to 100%). The mean TESS for those who underwent total resection with reconstruction was 72.0% (17% to 100%) and without reconstruction it was 53.3% (20% to 90%) and for those who underwent partial resection it was 76.3% (31.3% to 100%). The rate of local recurrence was 42.2% and this was more common in those treated by partial resection (p = 0.048). The risk of local recurrence was related to the margin achieved at resection. CONCLUSIONS: Given the high rate of local recurrence following excision of a tumour from the ilium, obtaining wide surgical margins should be a priority even if this requires more aggressive surgery. In young patients, where late recurrence may occur, more radical complete resection should be considered. When total resection of the ilium is considered, reconstruction should also be considered as it confers a higher functional outcome than total resection without reconstruction. Cite this article: Bone Joint J 2017;99-B:538-43.

Does osteofibrous dysplasia progress to adamantinoma and how should they be treated?

AIMS: The aim of this study was to identify any progression between benign osteofibrous dysplasia (OFD), OFD-like adamantinoma and malignant adamantinoma, and to investigate the rates of local recurrence, metastases and survival, in order to develop treatment algorithms for each. PATIENTS AND METHODS: A single institution retrospective review of all patients presenting with OFD, OFD-like adamantinoma and adamantinoma between 1973 and 2012 was undertaken. Complete data were available for 73 patients (42 with OFD; ten with an OFD-like adamantinoma and 21 with an adamantinoma). The mean follow-up was 10.3 years (3 to 25) for OFD, 9.2 years (3.0 to 26.3) for OFD-like and 11.6 years (0.25 to 33) for adamantinoma. RESULTS: The mean age at diagnosis for OFD was 13.5 years (1 to 49), 10.5 years (6 to 28) for OFD-like and 34 years (14 to 86) for adamantinoma. A total of 24 of the 42 patients with OFD (57%) have not required any treatment and have been managed with observation. A total of 18 of the 42 patients with OFD underwent surgery, 13 with curettage and five with resection. In all, three patients developed recurrence following curettage (23%) but none following resection. All these patients were cured with further limited surgery. A total of six patients initially diagnosed with OFD were subsequently found to have OFD-like adamantinoma. Of the ten patients initially diagnosed with OFD-like adamantinoma, three (30%) were managed with observation alone and seven underwent surgery, two with curettage and five with resection. Local recurrence arose in two patients, one each after curettage and resection. No patients with either OFD or an OFD-like adamantinoma developed metastases or had progression to adamantinoma. All patients with an adamantinoma were treated by surgery, three with curettage, six with amputation and 12 with excision. In all, two of the three treated with curettage developed local recurrence, requiring further surgery. Late development of both local recurrence and metastases led to a ten year disease specific survival of 93% which had dropped to 39% by 20 years. CONCLUSION: We found no evidence of progression from OFD to adamantinoma. Conservative management with observation or curettage is often successful for patients with OFD and OFD-like adamantinoma. Resection with clear margins is required for patients with adamantinoma. Late tumour recurrence is not uncommon in adamantinoma and prolonged follow-up should be considered. Cite this article: Bone Joint J 2017;99-B:409-16.

Is computer navigation when used in the surgery of iliosacral pelvic bone tumours safer for the patient?

AIMS: Due to the complex anatomy of the pelvis, limb-sparing resections of pelvic tumours achieving adequate surgical margins, can often be difficult. The advent of computer navigation has improved the precision of resection of these lesions, though there is little evidence comparing resection with or without the assistance of navigation. Our aim was to evaluate the efficacy of navigation-assisted surgery for the resection of pelvic bone tumours involving the posterior ilium and sacrum. PATIENTS AND METHODS: Using our prospectively updated institutional database, we conducted a retrospective case control study of 21 patients who underwent resection of the posterior ilium and sacrum, for the treatment of a primary sarcoma of bone, between 1987 and 2015. The resection was performed with the assistance of navigation in nine patients and without navigation in 12. We assessed the accuracy of navigation-assisted surgery, as defined by the surgical margin and how this affects the rate of local recurrence, the disease-free survival and the effects on peri-and post-operative morbidity. RESULTS: The mean age of the patients was 36.4 years (15 to 66). The mean size of the tumour was 10.9 cm. In the navigation-assisted group, the margin was wide in two patients (16.7%), marginal in six (66.7%) and wide-contaminated in one (11.1%) with no intralesional margin. In the non-navigated-assisted group; the margin was wide in two patients (16.7%), marginal in five (41.7%), intralesional in three (25.0%) and wide-contaminated in two (16.7%). Local recurrence occurred in two patients in the navigation-assisted group (22.2%) and six in the non-navigation-assisted group (50.0%). The disease-free survival was significantly better when operated with navigation-assistance (p = 0.048). The blood loss and operating time were less in the navigated-assisted group, as was the risk of a foot drop post-operatively. CONCLUSION: The introduction of navigation-assisted surgery for the resection of tumours of the posterior ilium and sacrum has increased the safety for the patients and allows for a better oncological outcome. Cite this article: Bone Joint J 2017;99-B:261-6.

Extraskeletal osteosarcoma: A European Musculoskeletal Oncology Society study on 266 patients.

PURPOSE: Prognosis of extraskeletal osteosarcoma (ESOS) is reported to be poorer than that of skeletal osteosarcoma. This multicenter retrospective study aimed to evaluate factors influencing ESOS prognosis. PATIENTS AND METHODS: Members of the European Musculoskeletal Oncology Society (EMSOS) submitted institutional data on patients with ESOS. RESULTS: Data from 274 patients treated from 1981 to 2014 were collected from 16 EMSOS centres; 266 patients were eligible. Fifty (18.7%) had metastases at diagnosis. Of 216 patients with localised disease, 211 (98%) underwent surgery (R0 = 70.6%, R1 = 27%). Five-year overall survival (OS) for all 266 patients was 47% (95% CI 40-54%). Five-year OS for metastatic patients was 27% (95% CI 13-41%). In the analysis restricted to the 211 localised patients who achieved complete remission after surgery 5-year OS was 51.4% (95% CI 44-59%) and 5-year disease-free survival (DFS) was 43% (95% CI 35-51%). One hundred twenty-one patients (57.3%) received adjuvant or neoadjuvant chemotherapy and 80 patients (37.9%) received radiotherapy. A favourable trend was seen for osteosarcoma-type chemotherapy versus soft tissue sarcoma-type (doxorubicin ± ifosfamide) regimens. For the 211 patients in complete remission after surgery, patient age, tumour size, margins and chemotherapy were positive prognostic factors for DFS and OS by univariate analysis. At multivariate analysis, patient age (≤40 years versus >40 years) (P = 0.05), tumour size (P = 0.0001) and receipt of chemotherapy (P = 0.006) were statistically significant prognostic factors for survival. CONCLUSION: Patient age and tumour size are factors influencing ESOS prognosis. Higher survival was observed in patients who received perioperative chemotherapy with a trend in favour of multiagent osteosarcoma-type regimen which included doxorubicin, ifosfamide and cisplatin.

Management of sarcomas possibly involving the knee joint when to perform extra-articular resection of the knee joint and is it safe?

We reviewed the oncological and functional outcomes of patients treated for a primary sarcoma possibly involving the knee joint and present an algorithm to guide treatment. The records of 76 patients who had a primary bone or soft tissue sarcoma possibly invading the knee between 1996 and 2012 were identified. Mean age and follow-up was 32 years (9-74) and 64 months (12-195), respectively. Patients were grouped according to the resection (Intra-articular [IAR] vs. Extra-articular [EAR] vs. Amputation/rotationplasty) for survival and functional outcomes. Overall 5 and 10 year survival was 61% and 53%, respectively. No differences in survival were found between the 3 groups (p = 0.55). Sixteen patients developed local recurrence with no difference between the groups. Mean MSTS score was 24.5 (12-30). Mean flexion at final follow-up was 106° (70-130°). We conclude that EAR of the knee allows for good oncologic and functional outcomes but with an increased risk of complications compared to IAR. Intra-operative assessment of joint involvement can be done in patients where joint infiltration by the tumour is not clear to avoid an unnecessary EAR. For chondrosarcoma patients with joint involvement, an EAR should be carefully considered because they present a significantly higher local recurrence risk.

What is the morbidity of a non-invasive growing prosthesis?

AIMS: Extendible endoprostheses have been available for more than 30 years and have become more sophisticated with time. The latest generation is 'non-invasive' and can be lengthened with an external magnetic force. Early results have shown a worryingly high rate of complications such as infection. This study investigates the incidence of complications and the need for further surgery in a cohort of patients with a non-invasive growing endoprosthesis. PATIENTS AND METHODS: Between 2003 and June 2014, 50 children (51 prostheses) had a non-invasive growing prosthesis implanted for a primary bone sarcoma. The minimum follow-up was 24 months for those who survived. Their mean age was 10.4 years (6 to 14). The incidence of complications and further surgery was documented. RESULTS: The mean follow-up was 64 months (20 to 145). The overall survivorship of the patients was 84% at three years and 70% at five years. Revision-free survival was 81.7% at three years and 61.6% at five years with competing risk analysis. Deep infection occurred in 19.6% of implants at a mean of 12.5 months (0 to 55). Other complications were a failure of the lengthening mechanism in five prostheses (9.8%) and breakage of the implant in two (3.9%). Overall, there were 53 additional operations (0 to 5 per patient). A total of seven patients (14%) underwent amputation, three for local recurrence and four for infection. Their mean limb length discrepancy was 4.3 mm (0 to 25) and mean Musculoskeletal Tumor Society Score functional score was 26.5 (18 to 30) at the final follow-up. CONCLUSIONS: When compared with previously published early results, this mid-term series has shown continued good functional outcomes and compensation for leg-length discrepancy. Infection is still the most common complication: post-operative wound healing problems, central line infection and proximal tibial location are the main risk factors. Cite this article: Bone Joint J 2016;98-B:1697-1703.

Non-Metastatic Pelvic Ewing's Sarcoma : oncologic outcomes and evaluation of prognostic factors.

We are reporting our experience on patients with -pelvic Ewing's Sarcoma treated in our unit. We retrospectively reviewed a series of patients with non-metastatic pelvic Ewing's sarcoma treated between 1977 and 2009. Patients were classified into three groups according to the local treatment received : Group 1. radiotherapy-chemo ; Group 2. surgery-chemo and Group 3. radiotherapy-surgery-chemo. Recurrence free and overall survival rates were calculated using the Kaplan-Meier method. Influence of various factors (age at diagnosis, gender, tumour site and size, chemotherapy response, surgical margins and type of treatment) on survival was assessed with a logistic regression model. A total of 85 patients were treated with a mean follow-up of 65.8 months and mean -tumour volume of 435ml. The 5-year survival for all patients was 40.7% decreased to 36.2% at 10 years. A significant prognostic factor identified was chemotherapy response only. There was a trend for improved survival and local control rates for patients who had chemotherapy and surgery and the results were apparent for all tumours irrespective of size but not statistically significant. Currently, the optimal management of pelvic Ewing's sarcoma is contro-versial but our study shows a trend for improved -survival for patients treated with chemotherapy and surgery.

Ewing's sarcoma: only patients with 100% of necrosis after chemotherapy should be classified as having a good response.

AIMS: The purpose of this study was to review a large cohort of patients and further assess the correlation between the histological response to chemotherapy in patients with Ewing's sarcoma with the overall (OS) and event-free survival (EFS). PATIENTS AND METHODS: All patients treated for Ewing's sarcoma between 1980 and 2012 were reviewed. Of these, 293 patients without metastases at the time of diagnosis and treated with chemotherapy and surgery were included. Patients were grouped according to the percentage of necrosis after chemotherapy: Group I: 0% to 50%, Group II: 51% to 99% and Group III: 100%. RESULTS: The mean age at diagnosis was 16 years (1 to 62) and the mean follow-up was 9.1 years (six months to 32.6 years). The OS and EFS for the series were 75% and 65% at five years. There were significant differences in survival between the groups of necrosis: 0% to 50% (OS: 49% and EFS: 45% at five years, respectively) compared with 51% to 99% (OS: 72% and EFS: 59% at five years, respectively) and 100% (OS: 94% and EFS: 81% at five years, respectively) (p < 0.001). There were no significant differences in survival between patients treated between 1980 and 1989 compared with those treated between 1990 and 1999, and those treated between 2000 and 2012 (p = 0.55). CONCLUSION: Only patients with 100% necrosis after chemotherapy should be classified as having a good response to chemotherapy because they have significantly better rates of survival compared with those with any viable tumour in the surgical specimen. Cite this article: Bone Joint J 2016;98-B:1138-44.