Abstract 3696: RNAseq of patient-derived cancer stem-like cells and exosomes provides new insights into Ewing's sarcoma

Background

Cancer stem-like cells (CSCs) are responsible for disease progression and relapse (Schatton et al, Bioessays 2009, 31:1038-49). Therefore, the eradication of Ewing's sarcoma (ES)-CSCs is expected to improve outcome for patients. Since the transfer of exosome cargo between cells drives ES progression (Ventura et al, Oncogene, 2016, 35:3944-54) or can be exploited as biomarker (Miller et al, Biology of the Cell 2013, 105:289-303; Tsugita et al, PLoS ONE 2013, 8:e77416) we have characterized primary patient-derived ES, paired ES-CSCs, and the exosomal cargo from these cultures to identify potential prognostic biomarkers of risk and targets for the development of new treatments.

Methods

ES taken at diagnosis and resection were collected following patient consent (GenoEwing; IRAS-167880). ES-CSCs were isolated using a functional self-renewing assay. EWSR1 translocations were confirmed by FISH using a break-apart probe and RT-PCR. Exosomes were collected after incubation of cultures in serum-free media for 48h, isolated using exoEasy Maxi kit (Qiagen) and characterized by Nanoparticle tracking, Western blot and flow cytometry. The expression of the ES-marker CD99 was investigated by immunocytochemistry, Western blot and flow cytometry. RNA was extracted from ES cells and paired exosomes using the miRNeasy Micro kit (Qiagen) and RNA quality confirmed employing the Agilent Bioanalyser. Total RNA libraries were prepared and sequenced using the HiSeq3000 (Illumina®). Reads were processed using fqtools (Droop, Bioinformatics 2016, 32:1883-4), aligned by STAR (Dobin et al, Bioinformatics 2013, 29:15-21) and differential expression was determined by DESeq2 (Anders et al, Genome Biology 2010, 11:R106). Genes were ranked on adjusted p value and log2 fold change; candidates were validated by RTqPCR.

Results

ES patient-derived cells expressed CD99 and contained an EWSR1 gene translocation (23/23). The median size of isolated ES exosomes was 84nm (range 32-132nm). Exosomes were enriched for small RNA (53±5% in exosomes vs 12±3% in cells). The optimal protein panel to identify ES exosomes is CD81, CD63 and TSG-101; CD9 was not detected. Consistent with the exosomal cell of origin, expression of CD99 was detected in 71-79% of isolated vesicles.

The RNA profile of parental cultures and daughter ES-CSCs was compared and two genes with increased expression in ES-CSCs were validated by RTqPCR (p<0.0001). Using a novel experimental approach in ES, we have sequenced the total RNA profile of paired exosomes from patient-derived ES cultures and confirmed the expression of CD99 and one putative ES-CSC biomarker in exosomes.

Conclusions

For the first time, we have sequenced paired exosomes and patient-derived ES cells to identify a potential prognostic biomarker and novel target for therapy.

Work funded by University of Leeds, Ewing's Sarcoma Research Trust (ESRT) and Bone Cancer Research Trust (BCRT).

Citation Format: Mariona Chicón Bosch, Elizabeth A. Roundhill, Alastair P. Droop, Michael Parry, Lee Jeys, Susan A. Burchill. RNAseq of patient-derived cancer stem-like cells and exosomes provides new insights into Ewing's sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3696.

Vascularized fibular epiphyseal transfer for proximal humeral reconstruction in children with a primary sarcoma of bone

Aims

Preserving growth following limb-salvage surgery of the upper limb in children remains a challenge. Vascularized autografts may provide rapid biological incorporation with the potential for growth and longevity. In this study, we aimed to describe the outcomes following proximal humeral reconstruction with a vascularized fibular epiphyseal transfer in children with a primary sarcoma of bone. We also aimed to quantify the hypertrophy of the graft and the annual growth, and to determine the functional outcomes of the neoglenofibular joint.

Patients and Methods

We retrospectively analyzed 11 patients who underwent this procedure for a primary bone tumour of the proximal humerus between 2004 and 2015. Six had Ewing’s sarcoma and five had osteosarcoma. Their mean age at the time of surgery was five years (two to eight). The mean follow-up was 5.2 years (1 to 12.2).

Results

The overall survival at five and ten years was 91% (confidence interval (CI) 95% 75% to 100%). At the time of the final review, ten patients were alive. One with local recurrence and metastasis died one-year post-operatively. Complications included seven fractures, four transient nerve palsies, and two patients developed avascular necrosis of the graft. All the fractures presented within the first postoperative year and united with conservative management. One patient had two further operations for a slipped fibular epiphysis of the autograft, and a hemi-epiphysiodesis for lateral tibial physeal arrest. Hypertrophy and axial growth were evident in nine patients who did not have avascular necrosis of the graft. The mean hypertrophy index was 65% (55% to 82%), and the mean growth was 4.6 mm per annum (2.4 to 7.6) in these nine grafts. At final follow-up, the mean modified functional Musculoskeletal Tumour Society score was 77% (63% to 83%) and the mean Toronto Extremity Salvage Score (TESS) was 84% (65% to 94%).

Conclusion

Vascularized fibular epiphyseal transfer preserves function and growth in young children following excision of the proximal humerus for a malignant bone tumour. Function compares favourably to other limb-salvage procedures in children. Longer term analysis is required to determine if this technique proves to be durable into adulthood. Cite this article: Bone Joint J 2018;100-B:535–41.

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.

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.

Best practices for the management of local-regional recurrent chordoma: a position paper by the Chordoma Global Consensus Group

Chordomas are rare, malignant bone tumors of the skull-base and axial skeleton. Until recently, there was no consensus among experts regarding appropriate clinical management of chordoma, resulting in inconsistent care and suboptimal outcomes for many patients. To address this shortcoming, the European Society of Medical Oncology (ESMO) and the Chordoma Foundation, the global chordoma patient advocacy group, convened a multi-disciplinary group of chordoma specialists to define by consensus evidence-based best practices for the optimal approach to chordoma. In January 2015, the first recommendations of this group were published, covering the management of primary and metastatic chordomas. Additional evidence and further discussion were needed to develop recommendations about the management of local-regional failures. Thus, ESMO and CF convened a second consensus group meeting in November 2015 to address the treatment of locally relapsed chordoma. This meeting involved over 60 specialists from Europe, the United States and Japan with expertise in treatment of patients with chordoma. The consensus achieved during that meeting is the subject of the present publication and complements the recommendations of the first position paper.

Navigation in Musculoskeletal Oncology: An Overview

Navigation in surgery has increasingly become more commonplace. The use of this technological advancement has enabled ever more complex and detailed surgery to be performed to the benefit of surgeons and patients alike. This is particularly so when applying the use of navigation within the field of orthopedic oncology. The developments in computer processing power coupled with the improvements in scanning technologies have permitted the incorporation of navigational procedures into day-to-day practice. A comprehensive search of PubMed using the search terms "navigation", "orthopaedic" and "oncology" yielded 97 results. After filtering for English language papers, excluding spinal surgery and review articles, this resulted in 38 clinical studies and case reports. These were analyzed in detail by the authors (GM and JS) and the most relevant papers reviewed. We have sought to provide an overview of the main types of navigation systems currently available within orthopedic oncology and to assess some of the evidence behind its use.

Minimising aseptic loosening in extreme bone resections: custom-made tumour endoprostheses with short medullary stems and extra-cortical plates

AIMS

Following the resection of an extensive amount of bone in the treatment of a tumour, the residual segment may be insufficient to accept a standard length intramedullary cemented stem. Short-stemmed endoprostheses conceivably have an increased risk of aseptic loosening. Extra-cortical plates have been added to minimise this risk by supplementing fixation. The aim of this study was to investigate the survivorship of short-stemmed endoprostheses and extra-cortical plates.

PATIENTS AND METHODS

The study involved 37 patients who underwent limb salvage surgery for a primary neoplasm of bone between 1998 and 2013. Endoprosthetic replacement involved the proximal humerus in nine, the proximal femur in nine, the distal femur in 13 and the proximal tibia in six patients. There were 12 primary (32%) and 25 revision procedures (68%). Implant survivorship was compared with matched controls. The amount of bone that was resected was > 70% of its length and statistically greater than the standard control group at each anatomical site.

RESULTS

The mean follow-up was seven years (one to 17). The mean length of the stem was 33 mm (20 to 60) in the humerus and 79 mm (34 to 100) in the lower limb. Kaplan-Meier analysis of survival of the implant according to anatomical site confirmed that there was no statistically significant difference between the short-stemmed endoprostheses and the standard stemmed controls at the proximal humeral (p = 0.84), proximal femoral (p = 0.57), distal femoral (p = 0.21) and proximal tibial (p = 0.61) sites. In the short-stemmed group, no implants with extra-cortical plate osseointegration suffered loosening at a mean of 8.5 years (range 2 to 16 years). Three of ten (30%) without osseointegration suffered aseptic loosening at a mean of 7.7 years (range 2 to 11.5 years).

CONCLUSION

When extensive resections of bone are required in the surgical management of tumours, and in revision cases, the addition of extra-cortical plates to short medullary stems has shown non-inferiority to standard length medullary stems and minimises aseptic failure. Cite this article: Bone Joint J 2017;99-B:1689-95.

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.

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.

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.

Angiomatoid fibrous histiocytoma: A case of local recurrence and metastases to loco-regional lymph nodes that responded to chemotherapy

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumour with intermediate malignant potential. We report the case of a patient with local recurrence of AFH in two locations and lymph node metastases 18 months after primary surgical excision. The patient was treated with six cycles of ifosfamide and doxorubicin chemotherapy and a further three courses of ifosfamide monotherapy. Reassessment imaging showed a good response to chemotherapy with reduction in size of the two tumours of local recurrence and the lymph node metastases. This case demonstrates that AFH can respond to chemotherapy, even though it is rarely used.

Surgical Innovation in Sarcoma Surgery

The field of orthopaedic oncology relies on innovative techniques to resect and reconstruct a bone or soft tissue tumour. This article reviews some of the most recent and important innovations in the field, including biological and implant reconstructions, together with computer-assisted surgery. It also looks at innovations in other fields of oncology to assess the impact and change that has been required by surgeons; topics including surgical margins, preoperative radiotherapy and future advances are discussed.

Suspended Manufacture of Biological Structures

A method for the production of complex cell-laden structures is reported, which allows high-levels of spatial control over mechanical and chemical properties. The potential of this method for producing complicated tissues is demonstrated by manufacturing a complex hard/soft tissue interface and demonstrating that cell phenotype can be maintained over four weeks of culture.

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.

Hypotensive Epidural Anesthesia Reduces Blood Loss in Pelvic and Sacral Bone Tumor Resections

BACKGROUND

Resection of pelvic and sacral tumors can cause severe blood loss, complications, and even postoperative death. Hypotensive epidural anesthesia has been used to mitigate blood loss after elective arthroplasty, but to our knowledge, it has not been studied as an approach that might make resection of pelvic and sacral tumors safer.

QUESTIONS/PURPOSES

The purposes of this study were (1) to compare the blood loss and blood product use for patients undergoing pelvic and sacral tumor surgery under standard anesthesia or hypotensive epidural anesthesia; (2) to assess the frequency of end-organ damage with the two techniques; and (3) to compare 90-day mortality between the two techniques.

METHODS

Between 2000 and 2014, 285 major pelvic and sacral resections were performed at one center. A total of 174 (61%) had complete data sets for analysis of blood loss, transfusion use, complications, and mortality at 90 days. Of those, 102 (59%) underwent hypotensive epidural anesthesia, whereas the remainder received standard anesthetic care. The anesthetic approach was determined by the anesthetists in charge of the case with hypotensive epidural anesthesia exclusively performed by one of two subspecialty trained anesthetists as their routine for major pelvic or sacral surgery. The groups were comparable in terms of potential confounding variables such as age, gender, tumor volume, and operation performed. Hypotensive epidural anesthesia was defined as a technique using an extensive epidural block up to T2-3 dermatome, peripherally administered low-concentration intravenous adrenaline infusion, and using unimpeded spontaneous respiration to achieve controlled hypotension, precise rate control of the heart, and enhanced velocity of venous return, all aggregated thus to minimize blood loss during pelvic surgery while preserving vital perfusion. The groups were assessed for perioperative blood loss calculated from pre- and postsurgery hemoglobin and transfusion use as well as postoperative complications, morbidity, and mortality at 90 days.

RESULTS

There was less mean blood loss in the hypotensive epidural anesthesia group (1457 mL, SD 1721, 95% confidence interval [CI], 1114-1801 versus 2421 mL, SD 2297, 95% CI, 1877-2965; p = 0.003). Patients in the hypotensive epidural anesthesia group on average received fewer packed red cell transfusions (2.7 units, SD 2.9, 95% CI, 2.1-3.2 versus 3.9 units, SD 4.4, 95% CI, 2.9-5.0; p = 0.03). There were no differences in the proportions of patients experiencing end-organ injury (7%, n = seven of 102 versus 6%, n = four of 72; p = 0.72). With the numbers available, there was no difference in 90-day mortality rate between groups (1.9%, n = two of 102 versus 1.3%, n = one of 72; p = 0.77).

CONCLUSIONS

We found that hypotensive epidural anesthesia resulted in less blood loss, fewer transfusions, and no apparent increase in serious complications in pelvic and sacral tumor surgery performed in the setting of a high-volume tertiary sarcoma referral hospital. We recommend that further collaborative studies be undertaken to confirm our results with hypotensive epidural anesthesia in surgery for pelvic tumors.

LEVEL OF EVIDENCE

Level III, therapeutic study.

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.

Very long-term outcomes after endoprosthetic replacement for malignant tumours of bone

AIMS

The aim of this study was to establish what happens to patients in the long term after endoprosthetic replacement for a primary malignant tumour of bone.

PATIENTS AND METHODS

We conducted a retrospective analysis of a prospectively maintained database to identify all patients who had undergone an endoprosthetic replacement more than 25 years ago and who were still alive. Their outcomes were investigated with reference to their complications and need for further surgery. A total of 230 patients were identified. Their mean age at diagnosis was 20.7 years (five to 62). The most common diagnosis was osteosarcoma (132). The most common site was the distal femur (102).

RESULTS

The mean follow-up was 29.4 years (25 to 43). A total of 610 further operations were undertaken, an average of 2.7 further operations per patient. A total of 42 patients (18%) still had the original prosthesis in place. The risk of amputation was 16% at 30 years (31 patients). Those without infection had a mean of 2.1 further operations (one to nine) while those with infection had a mean of 4.6 further operations (two to 11). The risk of infection persisted throughout the life of the prosthesis with a mean of 1% per year becoming infected. Of the 60 patients who developed an infection, 21 (35%) developed this following the primary procedure at a mean of 50 months, but another 19 developed this within a year of another surgical procedure. The risk of infection after any further surgery was 2.7%. The site with the highest risk of infection was the proximal tibia (43.3%).

TAKE HOME MESSAGE

This study highlights the inevitable need for further surgery following first-generation endoprosthetic reconstruction, although in most cases, limb salvage is maintained. Late complications, especially infection, continue for the lifetime of the implant. Cite this article: Bone Joint J 2016;98-B:857-64.

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.

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.

Extra-axial chordomas

INTRODUCTION

A chordoma is a slow growing malignant tumour of notochordal origin. A tumour with histological features that are identical to those of a chordoma may arise outside the axial skeleton. To date, there is little in the literature documenting their clinical course.

METHODS

Our large orthopaedic oncology database was used to document the clinical course of extra-axial chordoma.

RESULTS

Over a 30-year period, 131 patients diagnosed with a chordoma were treated at our unit. Only three (2.3%) of these cases were extra-axial chordomas: one in the femur, one in the ulna and one in the proximal fibula. All underwent surgical resection.

CONCLUSIONS

In view of the rarity of this tumour and the difficulty in confirming its diagnosis, we suggest that any suspected case is discussed with a specialist sarcoma multidisciplinary team so that the correct diagnosis can be achieved and treatment tailored accordingly.

Osteosarcoma of the pelvis

Aims

Osteosarcoma of the pelvis is a particularly difficult tumour to treat as it often presents late, may be of considerable size and/or associated with metastases when it presents, and is frequently chondroid in origin and resistant to chemotherapy. The aim of this study was to review our experience of managing this group of patients and to identify features predictive of a poor outcome.

Patients and Methods

Between 1983 and 2014, 121 patients, (74 females and 47 males) were treated at a single hospital: 74 (61.2%) patients had a primary osteosarcoma and 47 (38.8%) had an osteosarcoma which was secondary either to Paget’s disease (22; 18.2%) or to previous pelvic irradiation (25; 20.7%). The mean age of those with a primary osteosarcoma was 29.3 years (nine to 76) and their mean follow-up 2.9 years (0 to 29). The mean age of those with a secondary sarcoma was 61.9 years (15 to 85) and their mean follow-up was one year (0 to 14). A total of 22 patients with a primary sarcoma (52.4%) and 20 of those with a secondary sarcoma (47.6%) had metastases at the time of presentation.

Results

The disease-specific survival at five years for all patients was 27.2%. For those without metastases at the time of diagnosis, the five-year survival was 32.7%. Factors associated with a poor outcome were metastases at diagnosis and secondary tumours. In primary osteosarcoma, sacral location, surgical margin and a diameter > 10 cm were associated with a poor outcome.

Conclusion

In this, the largest single series of patients with an osteosarcoma of the pelvis treated in a single hospital, those with secondary tumours and those with metastases at presentation had a particularly poor outcome. For those with a primary sarcoma, sacral location, an intralesional margin and a diameter of > 10 cm were poor prognostic indicators. Cite this article: Bone Joint J 2016;98-B:555–63.

Resectable extra-pleural and extra-meningeal solitary fibrous tumours: A multi-centre prognostic study

BACKGROUND

Extra-pleural and extra-meningeal solitary fibrous tumour (SFT) is a rare sarcoma histotype curable with surgery in the majority of patients. The behaviour of these tumours ranges from indolent/very low grade to malignant/high grade but it is still not possible to accurately predict prognosis after surgery. We have investigated a multi-centre series to stratify the risk of recurrence to patients with SFTs.

METHODS

We retrospectively analysed the data from 243 patients who underwent surgery (2002-2011) at four sarcoma referral centres.

RESULTS

Upon univariate analysis, hypercellularity, atypia, necrosis, high mitotic rate (ie >4 mitoses/10 HPF) were associated with both disease-free and overall survival. Surgical margins were a significant prognostic factor for disease-free (P = 0.007) but not for overall survival. Unexpectedly, larger tumour size was associated with a better prognosis (P = 0.038) and fewer recurrences (P = 0.024). Upon multivariable analysis, high mitotic rate (hazard ratio, HR = 2.85, P = 0.002), cellular atypia (HR = 1.62, P = 0.015) and hypercellularity (HR = 1.82, P = 0.031) were significantly associated with recurrences. A SFT recurrence score has been provided to stratify risk of recurrence.

CONCLUSION

This study provides a prognostic model to stratify risk of recurrence in patients with resectable SFTs. This allows clinician to decide on an optimal follow-up strategy and to select patients that may benefit from adjuvant treatments.

Megaprostheses in the management of trauma of the knee

OBJECTIVE

Review the outcome of patients with complex fractures around the knee treated with megaprosthesis.

METHOD

Retrospective observational study of 10 patients was undertaken.

RESULTS

Six patients were treated with a distal femoral endoprosthesis (DEFPR) and four with an augmented rotating hinge knee replacement (RHK). The mean post-operative Toronto Extremity Salvage Score (TESS) was 62.5 for the whole cohort (RHK group 79.3, compared with 49.2 in the DFEPR group (p = 0.038), peri-prosthetic fracture group was 46.3, compared with 75.6 in native knee fracture group (p = 0.04)).

CONCLUSION

A megaprosthesis is a viable option in complex fractures around the knee.

The prognostic and therapeutic factors which influence the oncological outcome of parosteal osteosarcoma

The aim of this study was to evaluate the prognostic and therapeutic factors which influence the oncological outcome of parosteal osteosarcoma.

A total of 80 patients with a primary parosteal osteosarcoma were included in this retrospective study. There were 51 females and 29 males with a mean age of 29.9 years (11 to 78).

The mean follow-up was 11.2 years (1 to 40). Overall survival was 91.8% at five years and 87.8% at ten years. Local recurrence occurred in 14 (17.5%) patients and was associated with intralesional surgery and a large volume of tumour. On histological examination, 80% of the local recurrences were dedifferentiated high-grade tumours. A total of 12 (14.8%) patients developed pulmonary metastases, of whom half had either a dedifferentiated tumour or a local recurrence. Female gender and young age were good prognostic factors. Local recurrence was a poor prognostic factor for survival. Medullary involvement or the use of chemotherapy had no impact on survival.

The main goal in treating a parosteal osteosarcoma must be to achieve a wide surgical margin, as inadequate margins are associated with local recurrence. Local recurrence has a significant negative effect on survival, as 80% of the local recurrences are high-grade dedifferentiated tumours, and half of these patients develop metastases.

The role of chemotherapy in the treatment of parosteal osteosarcoma is not as obvious as it is in the treatment of conventional osteosarcoma. The mainstay of treatment is wide local excision.

Cite this article: Bone Joint J 2015;97-B:1698–1703.

Genome-wide DNA methylation profiling of recurrent and non-recurrent chordomas

Chordomas are an aggressive rare type of malignant bone tumors arising from the remnant of the notochord. Chordomas occur mainly in vertebral bones and account for 1-4% of malignant bone tumors. Management and treatment of chordomas are difficult as they are resistant to conventional chemotherapy; therefore, they are mainly treated with surgery and radiation therapy. In this study, we performed DNA methylation profiling of 26 chordomas and normal nucleus pulposus samples plus UCH-1 chordoma cell line using the Illumina Infinium HumanMethylation450 BeadChips. Combined bisulfite restriction analysis and bisulfite sequencing was used to confirm the methylation data. Gene expression was analyzed using RT-PCR before and after 5-aza-2'-deoxycytidine (5-azaDC) treatment of chordoma cell lines. Analysis of the HumanMethylation450 BeadChip data led to the identification of 8,819 loci (2.9%) that were significantly differentially methylated (>0.2 average β-value difference) between chordomas and nucleus pulposus samples (adjusted P < 0.05). Among these, 5,868 probes (66.5%) were hypomethylated, compared to 2,951 (33.5%) loci that were hypermethylated in chordomas compared to controls. From the 2,951 differentially hypermethylated probes, 33.3% were localized in the promoter region (982 probes) and, among these, 104 probes showed cancer-specific hypermethylation. Ingenuity Pathway Analysis indicates that the cancer-specific differentially methylated loci are involved in various networks including cancer disease, nervous system development and function, cell death and survival, cellular growth, cellular development, and proliferation. Furthermore, we identified a subset of probes that were differentially methylated between recurrent and non-recurrent chordomas. BeadChip methylation data was confirmed for these genes and gene expression was shown to be upregulated in methylated chordoma cell lines after treatment with 5-azaDC. Understanding epigenetic changes in chordomas may provide insights into chordoma tumorigenesis and development of epigenetic biomarkers.

An In Vitro Comparison of the Incorporation, Growth, and Chondrogenic Potential of Human Bone Marrow versus Adipose Tissue Mesenchymal Stem Cells in Clinically Relevant Cell Scaffolds Used for Cartilage Repair

AIM

To compare the incorporation, growth, and chondrogenic potential of bone marrow (BM) and adipose tissue (AT) mesenchymal stem cells (MSCs) in scaffolds used for cartilage repair.

METHODS

Human BM and AT MSCs were isolated, culture expanded, and characterised using standard protocols, then seeded into 2 different scaffolds, Chondro-Gide or Alpha Chondro Shield. Cell adhesion, incorporation, and viable cell growth were assessed microscopically and following calcein AM/ethidium homodimer (Live/Dead) staining. Cell-seeded scaffolds were treated with chondrogenic inducers for 28 days. Extracellular matrix deposition and soluble glycosaminoglycan (GAG) release into the culture medium was measured at day 28 by histology/immunohistochemistry and dimethylmethylene blue assay, respectively.

RESULTS

A greater number of viable MSCs from either source adhered and incorporated into Chondro-Gide than into Alpha Chondro Shield. In both cell scaffolds, this incorporation represented less than 2% of the cells that were seeded. There was a marked proliferation of BM MSCs, but not AT MSCs, in Chondro-Gide. MSCs from both sources underwent chondrogenic differentiation following induction. However, cartilaginous extracellular matrix deposition was most marked in Chondro-Gide seeded with BM MSCs. Soluble GAG secretion increased in chondrogenic versus control conditions. There was no marked difference in GAG secretion by MSCs from either cell source.

CONCLUSION

Chondro-Gide and Alpha Chondro Shield were permissive to the incorporation and chondrogenic differentiation of human BM and AT MSCs. Chondro-Gide seeded with BM MSCs demonstrated the greatest increase in MSC number and deposition of a cartilaginous tissue.

Chemical shift MRI can aid in the diagnosis of indeterminate skeletal lesions of the spine

OBJECTIVES

To evaluate the role of chemical shift MRI in the characterisation of indeterminate skeletal lesions of the spine as benign or malignant.

METHODS

Fifty-five patients (mean age 54.7 years) with 57 indeterminate skeletal lesions of the spine were included in this retrospective study. In addition to conventional MRI at 3 T which included at least sagittal T1WI and T2WI/STIR sequences, patients underwent chemical shift MRI. A cut-off value with a signal drop-out of 20 % was used to differentiate benign lesions from malignant lesions (signal drop-out <20 % being malignant).

RESULTS

There were 45 benign lesions and 12 malignant lesions. Chemical shift imaging correctly diagnosed 33 of 45 lesions as benign and 11 of 12 lesions as malignant. In contrast, there were 12 false positive cases and 1 false negative case based on chemical shift MRI. This yielded a sensitivity of 91.7 %, a specificity of 73.3 %, a negative predictive value of 97.1 %, a positive predictive value of 47.8 % and a diagnostic accuracy of 82.5 %.

CONCLUSIONS

Chemical shift MRI can aid in the characterisation of indeterminate skeletal lesions of the spine in view of its high sensitivity in diagnosing malignant lesions. Chemical shift MRI can potentially avoid biopsy in a considerable percentage of patients with benign skeletal lesions of the spine.

KEY POINTS

• Differentiating benign from malignant skeletal lesions of the spine can be challenging. • Utility of chemical shift MRI in characterising indeterminate spinal lesion is unreported. • This study demonstrates sensitivity 91.7 %, specificity 73.3 %, diagnostic accuracy 82.5 % for CSI. • CSI is useful in differentiating benign from malignant skeletal spine lesions. • Biopsy can potentially be avoided in some patients with benign skeletal lesions.

Can local recurrence of a sacral chordoma be treated by further surgery?

The purpose of this study was to evaluate the long-term outcome of patients with a sacral chordoma and the surgical management of locally recurrent disease.

Between October 1990 and August 2013 we operated on 54 consecutive patients with a sacral chordoma. There were 34 men and 20 women with a mean age of 60 years (25 to 86). The mean maximum diameter of the tumour was 9.3 cm (3 to 20).

The mean follow-up was 7.8 years (2 months to 23.4 years). The disease-specific survival was 82% at five years, 57% at ten years and 45% at 15 years. The local recurrence-free survival was 49% at five years, 37% at ten years and 20% at 15 years. Local recurrence occurred in 30 patients (56%) at a mean of 3.8 years (3 months to 13 years) post-operatively.

Survival after the treatment of recurrence was 89% at two years, 56% at five years and 19% at ten years. Of nine patients who had complete resection of a recurrence, one died after 72 months and eight remain disease-free. Incomplete resection of recurrent disease resulted in a survival of 54% at two years and 36% at five years.

For 12 patients with a local recurrence who were treated palliatively, survival was 81% at two years and 31% at five years.

A wide margin of resection gave the best chance of long-term survival and complete resection of local recurrence the best chance of control of disease.

Cite this article: Bone Joint J 2015;97-B:711–15.

Retrospective evaluation of the incidence of early periprosthetic infection with silver-treated endoprostheses in high-risk patients: case-control study

We conducted a case-control study to examine the merit of silver-coated tumour prostheses. We reviewed 85 patients with Agluna-treated (silver-coated) tumour implants treated between 2006 and 2011 and matched them with 85 control patients treated between 2001 and 2011 with identical, but uncoated, tumour prostheses. In all, 106 men and 64 women with a mean age of 42.2 years (18.4 to 90.4) were included in the study. There were 50 primary reconstructions (29.4%); 79 one-stage revisions (46.5%) and 41 two-stage revisions for infection (24.1%). The overall post-operative infection rate of the silver-coated group was 11.8% compared with 22.4% for the control group (p = 0.033, chi-square test). A total of seven of the ten infected prostheses in the silver-coated group were treated successfully with debridement, antibiotics, and implant retention compared with only six of the 19 patients (31.6%) in the control group (p = 0.048, chi-square test). Three patients in the silver-coated group (3.5%) and 13 controls (15.3%) had chronic periprosthetic infection (p = 0.009, chi-square test). The overall success rates in controlling infection by two-stage revision in the silver-coated group was 85% (17/20) compared with 57.1% (12/21) in the control group (p = 0.05, chi-square test). The Agluna-treated endoprostheses were associated with a lower rate of early periprosthetic infection. These silver-treated implants were particularly useful in two-stage revisions for infection and in those patients with incidental positive cultures at the time of implantation of the prosthesis. Debridement with antibiotic treatment and retention of the implant appeared to be more successful with silver-coated implants.

Knee salvage procedures: The indications, techniques and outcomes of large osteochondral allografts

The overall incidence of osteochondral defect in the general population is estimated to be 15 to 30 per 100000 people. These lesions can become symptomatic causing pain, swelling and decreased function of the knee, and may eventually progress to osteoarthritis. In the young and active population, partial or total knee arthroplasty (TKA) is rarely the treatment of choice due to risk of early failure. Osteochondral allograft transplantation has been demonstrated to be a safe and effective treatment of large osteochondral and chondral defects of the knee in appropriately selected patients. The treatment reduces pain, improves function and is a viable limb salvage procedure for patients, especially young and active patients for whom TKA is not recommended. Either large dowels generated with commercially available equipment or free hand shell allografts can be implanted in more posterior lesions. Current recommendations for fresh allografts stored at 4C advise implantation within 21-28 d of procurement for optimum chondrocyte viability, following screening and testing protocols. Higher rates of successful allograft transplantation are observed in younger patients, unipolar lesions, normal or corrected malalignment, and defects that are treated within 12 mo of symptom onset. Patients with bipolar lesions, uncorrectable malalignment, advanced osteoarthritis, and those over 40 tend to have less favourable outcomes.

Does total humeral endoprosthetic replacement provide reliable reconstruction with preservation of a useful extremity?

BACKGROUND

Controversy exists regarding the ideal method of reconstruction after proximal humeral resection and several reconstructive techniques have been reported. The reconstructive options are very limited when resection of the entire humerus is required. One option is endoprosthetic reconstruction, but there have been few published studies on the outcome of total humeral endoprosthetic reconstruction.

QUESTIONS/PURPOSES

The purposes of this study were (1) to assess the longevity of total humerus prostheses in those patients who survived their disease; (2) to review the complications associated with this prosthesis; and (3) to assess the Musculoskeletal Tumor Society functional score in survivors.

METHODS

Thirty-four patients (10 males, 24 females) with a mean age of 26 years (range, 7-86 years) were included in this study. Histological diagnosis was osteosarcoma in 15 patients, chondrosarcoma in seven, Ewing's sarcoma in seven, metastatic carcinoma in three, liposarcoma in one, and giant cell tumor of bone in one remaining patient. Twenty-nine patients had their total humeral endoprosthetic replacement for primary reconstruction, whereas the remaining five patients received their implants for failures with other reconstructive techniques. At a minimum followup of 3 months (mean, 8.2 years; range, 3 months to 29 years), 16 patients were alive with no evidence of disease, whereas 13 of the remaining 18 died with metastatic disease. Local recurrence was seen in five patients and all eventually died of disease progression.

RESULTS

According to the Kaplan-Meier survival analysis, the cumulative 10-year implant survival rate was 90%. Periprosthetic infection was seen in four patients, postoperative radial nerve palsy in one, and proximal migration of the prosthesis in three, whereas three patients needed a change of the articular elbow bushings at a mean of 16 years after the implant insertion. The mean Musculoskeletal Tumor Society functional score of the 28 patients who survived their disease for more than 12 months after the index procedure and could therefore be functionally assessed was 83% (range, 60%-93%).

CONCLUSIONS

From this small, preliminary report, we suggest that total humeral endoprosthetic replacement may be a reasonable option of reconstruction after tumor resection. We have shown that this prosthesis preserves the function of the hand. The local recurrence rate observed suggests that careful selection of patients is crucial. Infection was our most common surgical complication, but we showed that in those who survived their tumor, this prosthesis offers a method to preserve a functional upper extremity in some patients. Further study with more patients is necessary to confirm the value of this reconstruction method.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Mesenchymal chondrosarcoma: prognostic factors and outcome in 113 patients. A European Musculoskeletal Oncology Society study

BACKGROUND

Mesenchymal chondrosarcoma (MCS) is a distinct, very rare sarcoma with little evidence supporting treatment recommendations.

PATIENTS AND METHODS

Specialist centres collaborated to report prognostic factors and outcome for 113 patients.

RESULTS

Median age was 30 years (range: 11-80), male/female ratio 1.1. Primary sites were extremities (40%), trunk (47%) and head and neck (13%), 41 arising primarily in soft tissue. Seventeen patients had metastases at diagnosis. Mean follow-up was 14.9 years (range: 1-34), median overall survival (OS) 17 years (95% confidence interval (CI): 10.3-28.6). Ninety-five of 96 patients with localised disease underwent surgery, 54 additionally received combination chemotherapy. Sixty-five of 95 patients are alive and 45 progression-free (5 local recurrence, 34 distant metastases, 11 combined). Median progression-free survival (PFS) and OS were 7 (95% CI: 3.03-10.96) and 20 (95% CI: 12.63-27.36) years respectively. Chemotherapy administration in patients with localised disease was associated with reduced risk of recurrence (P=0.046; hazard ratio (HR)=0.482 95% CI: 0.213-0.996) and death (P=0.004; HR=0.445 95% CI: 0.256-0.774). Clear resection margins predicted less frequent local recurrence (2% versus 27%; P=0.002). Primary site and origin did not influence survival. The absence of metastases at diagnosis was associated with a significantly better outcome (P<0.0001). Data on radiotherapy indications, dose and fractionation were insufficiently complete, to allow comment of its impact on outcomes. Median OS for patients with metastases at presentation was 3 years (95% CI: 0-4.25).

CONCLUSIONS

Prognosis in MCS varies considerably. Metastatic disease at diagnosis has the strongest impact on survival. Complete resection and adjuvant chemotherapy should be considered as standard of care for localised disease.

Outcomes of a metal-on-metal total hip replacement system

INTRODUCTION

High short-term failure rates have been reported for a variety of metal-on-metal (MoM) total hip replacements (THRs) owing to adverse reactions to metal debris (ARMD). This has led to the withdrawal of certain poorly performing THRs. This study analysed the outcomes of a MoM THR system.

METHODS

Between 2004 and 2010, 578 uncemented MoM THRs (511 patients, mean age: 60.0 years) were implanted at one specialist centre. The THR system used consisted of the Corail(®) stem, Pinnacle(®) cup, Ultamet(®) liner and Articul/eze(®) femoral head (all DePuy, Leeds, UK). All patients were recalled for clinical review with imaging performed as necessary.

RESULTS

The mean follow-up duration was 5.0 years (range: 1.0-9.1 years). Overall, 39 hips (6.7%) in 38 patients (all 36 mm femoral head size) underwent revision at a mean time of 3.5 years (range: 0.01-8.3 years) from the index THR with 30 revisions (77%) performed in women. The cumulative eight-year survival rate for all THRs was 88.9% (95% confidence interval [CI]: 78.5-93.4%), with no difference (p=0.053) between male (95.2%, 95% CI: 84.2-98.7%) and female patients (85.3%, 95% CI: 70.2-92.1%) at eight years. Seventeen revisions (44%) were performed for ARMD. There was no significant difference in absolute postoperative Oxford hip scores between men and women (p=0.608). The mean acetabular inclination in unrevised THRs was 44.0°. Forty-seven non-revised THRs (8.7%) had blood metal ion concentrations above recommended thresholds (seven had periprosthetic effusions).

CONCLUSIONS

Although this MoM THR system has not failed as dramatically as other similar designs, we recommend against continued use and advise regular clinical surveillance to identify ARMD early.

Delayed diagnosis in metastatic lesions of the foot

INTRODUCTION

Pedal acrometastases are a rare complication of disseminated malignancy. To date, there is little in the literature documenting their clinical course.

METHODS

Our large orthopaedic oncology database was used to review the clinical course of symptomatic pedal acrometastases.

RESULTS

A total of 15 cases of pedal acrometastases were identified from 2,595 patients with metastases. The median age at presentation was 64.5 years (range: 14-83 years) and the median length of foot symptoms (predominantly pain and swelling) prior to diagnosis of metastasis was 16 weeks (range: 6-104 weeks). The median survival following diagnosis was 4.6 months (range: 2.3-104.5 months).

CONCLUSIONS

This study suggests that 0.58% of all osseous metastases involve the foot, and that symptoms of foot pain and swelling are often misdiagnosed, leading to delays in treatment. A high index of suspicion is required to diagnose pedal acrometastases early, thereby allowing early treatment so that the patient's quality of life can be maintained prior to death.

Osteosarcomas in the upper distal extremities: are their oncological outcomes similar to other sites?

AIMS

To investigate whether the oncological outcomes of patients with osteosarcomas in the upper distal extremity are similar to other sites and assess if limb-salvage surgery is safe in this location.

METHODS

The centre database was used to identify all patients with osteosarcomas in the lower humerus and distally between 1985 and 2012. Patient, tumor, treatment and outcome data was collected.

RESULTS

Twenty-six patients were included in this study. There were 9 males and 17 females with a mean age of 33 years (9-90). Seventeen osteosarcomas were located in the forearm bones (65%), six in the distal humerus (23%), and three (12%) in the hand. The three most common sub-diagnoses were parosteal 7/21 (33%), fibroblastic 4/21 (19%) and osteoblastic osteosarcomas 3/21 (14%). 2 patients (8%) had Paget's disease and 19 patients (73%) had high-grade tumors. Local excision was carried out in 12 patients (48%), 4 patients underwent endoprosthetic replacement (16%) and 9 underwent amputation (36%). The overall risk of local recurrence was 4% in our series. The five-year overall survival rate was 67%, with low tumor grade and parosteal type of osteosarcoma being positive predictors of survival.

CONCLUSION

This series has shown that patients with high-grade osteosarcomas of the upper distal extremities have a higher amputation risk than other limb sites but have favorable outcomes with limb-salvage surgery, comparable to other anatomical sites. Parosteal osteosarcomas in particular have a good prognosis.

The use of extracorporeally irradiated autografts in pelvic reconstruction following tumour resection

The aim of this study was to evaluate the functional and oncological outcome of extracorporeally irradiated autografts used to reconstruct the pelvis after a P1/2 internal hemipelvectomy.

The study included 18 patients with a primary malignant bone tumour of the pelvis. There were 13 males and five females with a mean age of 24.8 years (8 to 62). Of these, seven had an osteogenic sarcoma, six a Ewing’s sarcoma, and five a chondrosarcoma. At a mean follow-up of 51.6 months (4 to 185), nine patients had died with metastatic disease while nine were free from disease. Local recurrence occurred in three patients all of whom eventually died of their disease. Deep infection occurred in three patients and required removal of their graft in two while the third underwent a hindquarter amputation for extensive flap necrosis.

The mean Musculoskeletal Tumor Society functional score of the 16 patients who could be followed-up for at least 12 months was 77% (50 to 90). Those 15 patients who completed the Toronto Extremity Salvage Score questionnaire had a mean score of 71% (53 to 85).

Extracorporeal irradiation and re-implantation of bone is a valid method of reconstruction after an internal hemipelvectomy. It has an acceptable morbidity and a functional outcome that compares favourably with other available reconstructive techniques.

Cite this article: Bone Joint J 2014;96-B:1404–10

Desmoplastic fibroma of bone: A rare bone tumour

We identified thirteen patients with desmoplastic fibroma of bone treated at our institute over a 30 year period. The patients had a mean age of 25.9 years; eight were female. The incidence of desmoplastic fibroma of bone in all patients with benign bone tumours in our population is 0.003%. Surgical treatment ranged from primary amputation to intra-lesional curettage. The incidence of local recurrence was 15.4%. All cases of local recurrence after curettage or marginal excision demonstrated soft-tissue extension of their tumours on initial presentation suggesting that extra-osseous extension requires more radical surgery to control the disease.

This study presents the largest single centre series of desmoplastic fibroma of bone with a mean follow-up time of 8 years. We recommend wide surgical excision, particularly if the lesion can be resected without significant loss of function, as the treatment modality of choice with the lowest rate of recurrence. Patients undergoing intra-lesional or marginal resection need to be advised of the possibility of local recurrence and the need for long-term surveillance.

Diaphyseal osteosarcomas have distinct clinical features from metaphyseal osteosarcomas

AIMS

The aim of this study was to clarify the clinical features and outcomes of diaphyseal osteosarcoma.

METHODS

Patients with newly-diagnosed high-grade osteosarcoma occurring in the long bone were eligible for this retrospective study. Clinicopathological information was collected from our database and compared with 36 diaphyseal, 405 proximal and 519 distal metaphyseal, and 14 whole bone osteosarcoma patients. Additionally, case-control study matching by age, gender, site, and metastatic status at diagnosis with 1:3 ratio of 36 diaphyseal to 108 metaphyseal osteosarcomas patients was also conducted.

RESULTS

Five-year overall survival and metastasis-free survival of the three groups including diaphyseal, metaphyseal, and whole bone osteosarcoma patients showed significant difference (P = .029 and P = .013, respectively), although there is no difference for the survivals between proximal and distal metaphyseal osteosarcoma patients. Case-control study showed that patients with diaphyseal osteosarcomas had a significantly larger tumour (mean 13.5 cm vs 10 cm, P = .026), and demonstrated higher pathologic fracture rate (28% vs 12%, P = .033), superior 5-year metastasis-free survival (74% vs 40%, P = .0068), and slightly better 5-year overall survival (68% vs 46%, P = .074). Prognostic factor analysis showed that a pathologic fracture significantly decreased the survival of the patients with diaphyseal osteosarcoma.

CONCLUSIONS

The current study showed that diaphyseal osteosarcoma has distinct clinical features from metaphyseal osteosarcoma having an increased risk of pathologic fractures but with favorable survival outcome.

Is limb salvage surgery safe for bone sarcomas identified after a previous surgical procedure?

Bone sarcomas are rare cancers and orthopaedic surgeons come across them infrequently, sometimes unexpectedly during surgical procedures. We investigated the outcomes of patients who underwent a surgical procedure where sarcomas were found unexpectedly and were subsequently referred to our unit for treatment. We identified 95 patients (44 intra-lesional excisions, 35 fracture fixations, 16 joint replacements) with mean age of 48 years (11 to 83); 60% were males (n = 57). Local recurrence arose in 40% who underwent limb salvage surgery versus 12% who had an amputation. Despite achieving local control, overall survival was worse for patients treated with amputation rather than limb salvage (54% vs 75% five-year survival). Factors that negatively influenced survival were invasive primary surgery (fracture fixation, joint replacement), a delay of greater than two months until referral to our oncology service, and high-grade tumours. Survival in these circumstances depends mostly on factors that are determined prior to definitive treatment by a tertiary orthopaedic oncology unit. Limb salvage in this group of patients is associated with a higher rate of inadequate marginal surgery and, consequently, higher local recurrence rates than amputation, but should still be attempted whenever possible, as local control is not the primary determinant of survival.

Cite this article: Bone Joint J 2014;96-B:665–72.

Synovial chondrosarcoma arising in synovial chondromatosis

Primary synovial chondromatosis (SC) is a rare proliferative disorder that causes pain, swelling, and restriction of movement to the joints it affects. The disease frequently runs a protracted course, often requiring multiple surgical procedures to obtain some control. Few reports exist detailing the natural history of SC, although malignant transformation to synovial chondrosarcoma (CHS) is recognized to be a rare event. The aim of our study was to review a large orthopaedic oncology database in order to evaluate the incidence of CHS arising from SC. We identified 78 patients who have presented to our centre with primary synovial chondromatosis (SC). Of those patients, 5 went on to develop malignant change. This represents a 6.4% incidence of developing synovial chondrosarcoma (CHS) within preexisting primary synovial chondromatosis. The patients had a mean age of 28 years at first diagnosis with synovial chondromatosis with the median time from original diagnosis to malignant transformation being 20 years (range 2.7-39 yrs).

The outcome of surgical treatment for peri-acetabular metastases

We reviewed the outcome of patients who had been treated operatively for symptomatic peri-acetabular metastases and present an algorithm to guide treatment. The records of 81 patients who had been treated operatively for symptomatic peri-acetabular metastases between 1987 and 2010 were identified. There were 27 men and 54 women with a mean age of 61 years (15 to 87). The diagnosis, size of lesion, degree of pelvic continuity, type of reconstruction, World Health Organization performance status, survival time, pain, mobility and complications including implant failure were recorded in each case. The overall patient survivorship at five years was 5%. The longest lived patient survived 16 years from the date of diagnosis. The mean survival was 23 months (< 1 to 16 years) and the median was 15 months. At follow-up 14 patients remained alive. Two cementoplasties failed because of local disease progression. Three Harrington rods broke: one patient needed a subsequent Girdlestone procedure. One 'ice-cream cone' prosthesis dislocated and was subsequently revised without further problems. We recommend the 'ice-cream cone' for pelvic discontinuity and Harrington rod reconstruction for severe bone loss. Smaller defects can be safely managed using standard revision hip techniques.

Giant cell tumour of the proximal femur

The purpose of this study was to assess whether the use of a joint-sparing technique such as curettage and grafting was successful in eradicating giant cell tumours of the proximal femur, or whether an alternative strategy was more appropriate.

Between 1974 and 2012, 24 patients with a giant cell tumour of the proximal femur were treated primarily at our hospital. Treatment was either joint sparing or joint replacing. Joint-sparing treatment was undertaken in ten patients by curettage with or without adjunctive bone graft. Joint replacement was by total hip replacement in nine patients and endoprosthetic replacement in five. All 11 patients who presented with a pathological fracture were treated by replacement.

Local recurrence occurred in five patients (21%): two were treated by hip replacement, three by curettage and none with an endoprosthesis. Of the ten patients treated initially by curettage, six had a successful outcome without local recurrence and required no further surgery. Three eventually needed a hip replacement for local recurrence and one an endoprosthetic replacement for mechanical failure. Thus 18 patients had the affected joint replaced and only six (25%) retained their native joint. Overall, 60% of patients without a pathological fracture who were treated with curettage had a successful outcome.

Cite this article: Bone Joint J 2014;96-B:127–31.

Can computer navigation-assisted surgery reduce the risk of an intralesional margin and reduce the rate of local recurrence in patients with a tumour of the pelvis or sacrum?

We hypothesised that the use of computer navigation-assisted surgery for pelvic and sacral tumours would reduce the risk of an intralesional margin. We reviewed 31 patients (18 men and 13 women) with a mean age of 52.9 years (13.5 to 77.2) in whom computer navigation-assisted surgery had been carried out for a bone tumour of the pelvis or sacrum. There were 23 primary malignant bone tumours, four metastatic tumours and four locally advanced primary tumours of the rectum. The registration error when using computer navigation was < 1 mm in each case. There were no complications related to the navigation, which allowed the preservation of sacral nerve roots (n = 13), resection of otherwise inoperable disease (n = 4) and the avoidance of hindquarter amputation (n = 3). The intralesional resection rate for primary tumours of the pelvis and sacrum was 8.7% (n = 2): clear bone resection margins were achieved in all cases. At a mean follow-up of 13.1 months (3 to 34) three patients (13%) had developed a local recurrence. The mean time alive from diagnosis was 16.8 months (4 to 48). Computer navigation-assisted surgery is safe and has reduced our intralesional resection rate for primary tumours of the pelvis and sacrum. We recommend this technique as being worthy of further consideration for this group of patients.