Aims. Surgical limb sparing for knee-bearing paediatric bone sarcoma is considered to have a clinically significant influence on postoperative function due to complications and leg-length discrepancies. However, researchers have not fully evaluated the long-term postoperative functional outcomes. Therefore, in this study, we aimed to elucidate the risk factors and long-term functional prognosis associated with paediatric limb-sparing surgery. Methods. We reviewed 40 patients aged under 14 years who underwent limb-sparing surgery for knee bone sarcoma (15 cases in the proximal tibia and 25 in the distal femur) between January 2000 and December 2013, and were followed up for a minimum of five years. A total of 35 patients underwent reconstruction using artificial materials, and five underwent biological reconstruction. We evaluated the patients’ postoperative complications, survival rate of reconstruction material, and limb, limb function, and leg-length discrepancy at the final follow-up, as well as the risk factors for each. Results. Complications were observed in 55% (22/40) of patients. The limb survival and reconstruction material rates at five and ten years were 95% and 91%, and 88% and 66%, respectively. Infection was the only risk factor in both survivals (p < 0.001, p = 0.019). In the 35 patients with limb preservation, the median International Society of Limb Salvage (ISOLS) score at the final follow-up was 80 (47% to 97%). Younger age (p = 0.027) and complications (p = 0.005) were poor prognostic factors. A negative correlation was found between age and leg-length discrepancy (R = −0.426; p = 0.011). The ISOLS scores were significantly lower in patients with a leg-length discrepancy of more than 5 cm (p = 0.005). Conclusion. Young age and complications were linked to an unfavourable functional prognosis. Leg-length correction was insufficient, especially in very young children, resulting in decreased function of the affected limb. Limb-sparing surgery for these children remains a considerable challenge. Cite this article: Bone Jt Open 2024;5(10):868–878

There is more than one option for proximal humerus reconstruction after oncological resection but we believe osteochondral allografts provide a good biological solution for these defects. We report three cases with different histological diagnoses and different results following such reconstruction. The aim is to highlight the advantages and disadvantages of this surgical procedure. The first case report concerns a 15-year-old boy (M.P.) with Ewing’s sarcoma of the proximal humerus. The gleno-humeral articulation and most of the rotator cuff were not involved by the disease. An allograft was used for the reconstruction after satisfactory resection. This allowed good restoration of the function quickly. At 12 months there was a fatigue fracture in the allograft, which required revision with a modular prosthesis. In another patient, a young woman (E.C.), a proximal humeral defect was reconstructed following resection of a benign lesion, fibrous dysplasia. She does not have complete restoration of function but there are no complications at 3 year follow up. The last case is a 49-year-old woman (M.M.), who had osteochondral allograft reconstruction of the proximal humerus after resection of a completely destroyed head by a giant cell tumour. She had good initial results but required revision surgery with Kuntscher nail and vancomycin was added to the cement due to infection. The biological articular reconstruction after oncological wide resection allows good functional results when rotator cuff tendons are available and allografts permit a good and fitting reinsertion. The reported early restoration of function in the young boy (case 1) has to be considered in the stress-fracture genesis. The authors consider that the lack of motion in case 2 was due to a non-aggressive and careful rehabilitation: a quite poor functional result to avoid complications. The case 3 failure is due to an infection, one of most frequent complications in allograft implants. The choice of using an osteochondral allograft must be considered as a useful alternative with prosthetic replacements

Giant cell tumor of bone is a benign lesion that is ‘locally aggressive and potentially malignant’. The most common specific location of ‘GCT’ is about the knee (50–65%), followed by the distal radius (10–12%), sacrum (4–9%) and proximal humerus (3%–8%). The pelvis is recognized as an infrequent site of involvement accounting for as few as 2% to 3% of all giant cell tumors. Giant cell tumors often can reach an alarming size in the pelvis jeopardizing the surrounding structures.

Treatment options described in literature for pelvic giant cell tumors include radiation therapy; surgery with intralesional margin; surgery with an intralesional margin and physical adjuvants, and surgery with wide margins.

Following Type II (Periacetabular) resections the two preferred modes of reconstruction are either Saddle Prosthesis or Ilio femoral fusion. But, in patients with extensive periacetabular involvement with tumor extension into ilium the type II resection has to be combined with a Type I (Ilial) resection. This may result in insufficient ilium being available for reconstruction to consider either a iliofemoral fusion or a saddle prosthesis. In such situations we recommend Sacroiliofemoral fusion as a novel variation of iliofemoral arthrodesis.

We present two cases of GCT of pelvis with significant periacetabular involvement treated by Sacroiliofemoral fusion. A follow up at 2 years in both cases showed no recurrences, mean MSTS of 21 & TESS of 70.

This paper discusses the various treatment options for such extensive periacetbular giant cell tumors, operative technique for sacroiliofemoral fusion, outcome evaluation after 2 years by MSTS & Toronto Extremity Salvage scores.

We reviewed 25 patients who had undergone resection of a primary bone sarcoma which extended to within 5 cm of the knee with reconstruction by a combination of a free vascularised fibular graft and a massive allograft bone shell. The distal femur was affected in four patients and the proximal tibia in 21. Their mean age at the time of operation was 19.7 years (5 to 52) and the mean follow-up period 140 months (28 to 213). Three vascularised transfers failed. The mean time to union of the fibula was 5.6 months (3 to 10) and of the allograft 19.6 months (10 to 34). Full weight-bearing was allowed at a mean of 21.4 months (14 to 36). The mean functional score at final follow-up was 27.4 (18 to 30) using a modfied 30-point Musculoskeletal Tumour Society rating system. The overall limb-salvage rate was 88%. The results of our study suggest that the combined use of a vascularised fibular graft and allograft is of value as a limb-salvage procedure for intercalary reconstruction after resection of bone tumours around the knee, especially in skeletally immature patients.

The purpose of this study was to assess the outcome of 15 patients (mean age 13.6 years (7 to 25)) with a primary sarcoma of the tibial diaphysis who had undergone excision of the affected segment that was then irradiated (90 Gy) and reimplanted with an ipsilateral vascularised fibular graft within it.

The mean follow-up was 57 months (22 to 99). The mean time to full weight-bearing was 23 weeks (9 to 57) and to complete radiological union 42.1 weeks (33 to 55). Of the 15 patients, seven required a further operation, four to obtain skin cover. The mean Musculoskeletal Society Tumor Society functional score at final follow-up was 27 out of 30 once union was complete. The functional results were comparable with those of allograft reconstruction and had a similar rate of complication.

We believe this to be a satisfactory method of biological reconstruction of the tibial diaphysis in selected patients.

The December 2023 Oncology Roundup. 360. looks at: A single osteotomy technique for frozen autograft; Complications, function, and survival of tumour-devitalized autografts used in patients with limb-sparing surgery; Is liquid nitrogen recycled bone and vascular fibula the biological reconstruction of choice?; Solitary pulmonary metastases at first recurrence of osteosarcoma; Is a radiological score able to predict resection-grade chondrosarcoma in primary intraosseous lesions of the long bones?; Open versus core needle biopsy in lower-limb sarcoma – current practice patterns and patient outcomes; Natural history of intraosseous low-grade chondroid lesions of the proximal humerus; Local treatment modalities and event-free survival in patients with localized Ewing’s sarcoma; Awaiting biopsy results in solitary pathological proximal femoral fractures

Aims. Reconstruction after osteoarticular resection of the proximal ulna for tumours is technically difficult and little has been written about the options that are available. We report a series of four patients who underwent radial neck to humeral trochlea transposition arthroplasty following proximal ulnar osteoarticular resection. Methods. Between July 2020 and July 2022, four patients with primary bone tumours of the ulna underwent radial neck to humeral trochlea transposition arthroplasty. Their mean age was 28 years (12 to 41). The functional outcome was assessed using the range of motion (ROM) of the elbow, rotation of the forearm and stability of the elbow, the Musculoskeletal Tumor Society score (MSTS), and the nine-item abbreviated version of the Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH-9) score. Results. All patients were available for follow-up at a mean of 33 months (25 to 43) and were disease-free. The mean flexion arc was 0° to 105°. Three patients had complications. One had neuropraxia of the ulnar nerve. The symptoms resolved after three months. In one patient, the screw used for fixation of the triceps tendon became exposed and was removed, six months postoperatively. One patient with wound dehiscence required a local flap for soft-tissue cover, four months postoperatively. At a mean follow-up of 33 months (25 to 43), the mean flexion arc was 0° to 105°. All patients had full supination (85°) but none had any pronation. The mean MSTS score was 23.5 (23 to 24) and mean QuickDASH-9 score was 26.13 (16.5 to 35.75). Three patients had varus-valgus instability on examination, although only one had a sense of instability while working. Conclusion. Radial neck to humeral trochlea transposition offers a satisfactory and cost-effective biological reconstructive option after osteoarticular resection of the proximal ulna, in the short term. It provides good elbow function and, being a biological reconstruction option using native bone, is likely to provide long-term stability and durability. Cite this article: Bone Joint J 2024;106-B(11):1301–1305

Aims. The use of frozen tumour-bearing autograft combined with a vascularized fibular graft (VFG) represents a new technique for biological reconstruction of massive bone defect. We have compared the clinical outcomes between this technique and Capanna reconstruction. Methods. From June 2011 to January 2016 a retrospective study was carried out of patients with primary osteosarcoma of lower limbs who underwent combined biological intercalary reconstruction. Patients were categorized into two groups based on the reconstructive technique: frozen tumour-bearing autograft combined with concurrent VFG (Group 1) and the Capanna method (Group 2). Demographics, operating procedures, oncological outcomes, graft union, limb function, and postoperative complications were compared. Results. A total of 23 patients were identified for analysis: eight in Group 1 and 15 in Group 2. There was no difference in the demographics (age, sex, and affected site) and operating procedures (resection length, duration of surgery, and blood loss) between the two groups. No significant difference was found in local recurrence in Group 1 versus Group 2 (p = 0.585). Mean union time for the frozen autograft-host junction was 8.4 months (7.0 to 11.0), significantly earlier than for the allograft-host junction in Group 2 (mean 14.1 months (10.0 to 28.0); p < 0.001). Mean Musculoskeletal Tumor Society scores in groups 1 and 2 were 90.3% (SD 7.4%) and 88.0% (SD 9.0%), respectively, with no significant statistical difference (p = 0.535). In terms of complications, infection (n = 1, 6.7%) and delayed union (n = 2, 13.3%) occurred in Group 2, but no such complications were observed in Group 1. Conclusion. Frozen tumour-bearing autograft in combination with VFG can be used as an alternative to the Capanna reconstruction in properly selected patients with osteosarcoma. Cite this article: Bone Joint J 2020;102-B(5):646–652

Abstract. Introduction. Active, middle-aged patients with symptomatic cartilage or osteochondral defects can find themselves in a treatment gap when they have failed conservative measures but are not yet eligible for conventional arthroplasty. Data from various cohort studies suggests that focal knee resurfacing implants such as HemiCAP, UniCAP, Episealer or BioBoly are cost-effective solutions to alleviate pain, improve function and delay or eliminate the need for conventional replacement. A systematic review and meta-analysis were conducted in order to(i) evaluate revision rates and implant survival of focal resurfacing; (ii) explore surgical complications; and (iii) evaluate various patient reported clinical outcome measures. Methodology. PubMED, Cochrane Library and Medline databases were searched in February 2022 for prospective and retrospective cohort studies evaluating any of the available implant types. Data on incidence of revision, complications and various patient reported outcome measures was sourced. Results. A total of 24 unique studies were identified with a total of 1465 enrolled patients. A revision rate of 12.97% over a 5.9 year weighted mean follow-up period was observed across all implant types. However, in one series a Kaplan-Meir survival as high as 92.6% at a 10-year follow-up period was noted. A statistically significant improvement was documented across multiple subjective clinical outcomes scores. There was a low reported incidence of post-operative complications such as aseptic loosening or deep wound infection. Conclusions. Focal femoral resurfacing appears to be a viable treatment option for focal symptomatic chondral lesions in patients beyond biological reconstruction, with low revision rates and high patient satisfaction

In the last years, 3d printing has progressively grown and it has reached a solid role in clinical practice. The main applications brought by 3d printing in orthopedic surgery are: preoperative planning, custom-made surgical guides, custom-made im- plants, surgical simulation, and bioprinting. The replica of the patient's anatomy, starting from the elaboration of medical volumetric images (CT, MRI, etc.), allows a progressive extremization of treatment personalization that could be tailored for every single patient. In complex cases, the generation of a 3d model of the patient's anatomy allows the surgeons to better understand the case — they can almost “touch the anatomy” —, to perform a more ac- curate preoperative planning and, in some cases, to perform device positioning before going to the surgical room (i.e. joint arthroplasty). 3d printing is also commonly used to produce surgical cutting guides, these guides are positioned intraoperatively on given landmarks to guide the surgeon to perform a specific surgical act (bone osteotomy, bone resection, implant position, etc.). In total knee arthroplasty, custom-made cutting guides have been developed to help the surgeon align the femoral and tibial components to the pre-arthritic condition with- out the use of the intramedullary femoral guide. 3d printed custom-made implants represent an emerging alternative to biological reconstructions especially after oncologic resection surgery or in case of complex arthroplasty revision surgery. Custom-made implants are designed to re- place the original shape and size of the patient's bone and they allow an extreme personalization of the treatment for every single patient. Patient-specific surgical simulation is a new frontier that promises great benefits for surgical training. a solid 3d model of the patient's anatomy can faithfully reproduce the surgical complexity of the patient and it allows to generate surgical simulators with increasing difficulty to adapt the difficulties of the course with the level of the trainees performing structured training paths: from the “simple” case to the “complex” case

Parosteal osteosarcoma is an uncommon tumour. Different methods of surgical treatment have been reported. Aim of this study was to investigate differences in outcome after biological and prosthetic reconstruction. Since August 1969, 28 patients have been treated at our institution. Average age was 26 years, range 15 to 59 years. Patient data was retrospectively reviewed within the prospective database of the Vienna Tumour Registry. Average follow-up was 133.9 months, range 8.4 to 382.6 months. Two patients died of disease 8.4 and 81.4 months after operation, respectively, another patient died due to unrelated causes 330.4 months postoperatively. All surviving patients were followed for a minimum of 3.6 months. Location of the lesion was the distal femur (19), proximal humerus (four), proximal tibia (three), mid-diaphyseal and proximal femur (one each). In 12 patients endoprosthetic reconstruction was indicated. Biological reconstruction was performed in 11 patients. Three patients underwent rotationplasty, two patients were amputated. Eight of 12 patients with endoprostheses have been revised, five have had multiple revisions. Causes for revision were bushing wear (four), aseptic loosening (four), infection (three) and periprosthetic fracture (one). There was no local recurrence in the endoprosthetic group. Two of 11 patients with biological reconstruction underwent revision due to pseudarthrosis and femoral fracture, respectively. There were two cases of local recurrence requiring secondary amputation. Two patients with rotationplasty underwent revision for wound healing disturbance and thrombectomy, respectively. Three patients developed lung metastases, leading to death of disease in two cases of amputation and rotationplasty. One patient with endoprosthetic reconstruction was alive 129.0 months after pulmonary metastasectomy. Functional outcome was satisfactory in all patients; there were no significant differences between patients with endoprosthetic or biological reconstruction. Biological reconstruction showed less revisions compared to endoprostheses, however, exact preoperative planning is required to obtain clear margins of resection

Aims. After intercalary resection of a bone tumour from the femur, reconstruction with a vascularized fibular graft (VFG) and massive allograft is considered a reliable method of treatment. However, little is known about the long-term outcome of this procedure. The aims of this study were to determine whether the morbidity of this procedure was comparable to that of other reconstructive techniques, if it was possible to achieve a satisfactory functional result, and whether biological reconstruction with a VFG and massive allograft could achieve a durable, long-lasting reconstruction. Patients and Methods. A total of 23 patients with a mean age of 16 years (five to 40) who had undergone resection of an intercalary bone tumour of the femur and reconstruction with a VFG and allograft were reviewed clinically and radiologically. The mean follow-up was 141 months (24 to 313). The mean length of the fibular graft was 18 cm (12 to 29). Full weight-bearing without a brace was allowed after a mean of 13 months (seven to 26). Results. At final follow-up, the mean Musculoskeletal Tumor Society Score of 22 evaluable patients was 94% (73 to 100). Eight major complications, five fractures (21.7%), and three nonunions (13%) were seen in seven patients (30.4%). Revision-free survival was 72.3% at five, ten, and 15 years, with fracture and nonunion needing surgery as failure endpoints. Overall survival, with removal of allograft or amputation as failure endpoints, was 94.4% at five, ten, and 15 years. Discussion. There were no complications needing surgical revision after five years had elapsed from surgery, suggesting that the mechanical strength of the implant improves with time, thereby decreasing the risk of complications. In young patients with an intercalary bone tumour of the femur, combining a VFG and massive allograft may result in a reconstruction that lasts a lifetime. Cite this article: Bone Joint J 2018;100-B:378–86

The October 2015 Children’s orthopaedics Roundup. 360 . looks at: Radiographic follow-up of DDH; When the supracondylar goes wrong; Apophyseal avulsion fractures; The ‘pulled elbow’; Surgical treatment of active or aggressive aneurysmal bone cysts in children; Improving stability in supracondylar fractures; Biological reconstruction may be preferable in children’s osteosarcoma; The paediatric hip fracture

Aims. We retrospectively report our experience of managing 30 patients with a primary malignant tumour of the distal tibia; 25 were treated by limb salvage surgery and five by amputation. We compared the clinical outcomes of following the use of different methods of reconstruction. Patients and Methods. There were 19 male and 11 female patients. The mean age of the patients was 19 years (6 to 59) and the mean follow-up was 5.1 years (1.25 to 12.58). Massive allograft was used in 11 patients, and autograft was used in 14 patients. The time to union, the survival time of the reconstruction, complication rate, and functional outcomes following the different surgical techniques were compared. The overall patient survival was also recorded. Results. Out of 14 patients treated with an autograft, 12 (86%) achieved union at both the proximal and distal junctions. The time to union at both junctions of the autograft was significantly shorter than in those treated with an allograft (11.1 vs 17.2 months, p = 0.02; 9.5 vs 16.2 months, p = 0.04). The complication rate of allograft reconstruction was 55%. The five patients treated with an amputation did not have a complication. Out of the 25 patients who were treated with limb salvage, three (12%) developed local recurrence and underwent amputation. The mean functional Musculoskeletal Tumor Society (MSTS) score after autograft reconstruction was higher than after allograft reconstruction (81% vs 67%; p = 0.06), and similar to that after amputation (81% vs 82%; p = 0.82). The two- and five-year overall rates of survival were 83% and 70%, respectively. Conclusions. This consecutive case series supports the safety of limb salvage and the effectiveness of biological reconstruction after the resection of a primary tumour of the distal tibia. Autograft might be a preferable option. In some circumstances, below-knee amputation remains a valid option

We report our experience of using a computer navigation system to aid resection of malignant musculoskeletal tumours of the pelvis and limbs and, where appropriate, their subsequent reconstruction. We also highlight circumstances in which navigation should be used with caution. We resected a musculoskeletal tumour from 18 patients (15 male, three female, mean age of 30 years (13 to 75) using commercially available computer navigation software (Orthomap 3D) and assessed its impact on the accuracy of our surgery. Of nine pelvic tumours, three had a biological reconstruction with extracorporeal irradiation, four underwent endoprosthetic replacement (EPR) and two required no bony reconstruction. There were eight tumours of the bones of the limbs. Four diaphyseal tumours underwent biological reconstruction. Two patients with a sarcoma of the proximal femur and two with a sarcoma of the proximal humerus underwent extra-articular resection and, where appropriate, EPR. One soft-tissue sarcoma of the adductor compartment which involved the femur was resected and reconstructed using an EPR. Computer navigation was used to aid reconstruction in eight patients. Histological examination of the resected specimens revealed tumour-free margins in all patients. Post-operative radiographs and CT showed that the resection and reconstruction had been carried out as planned in all patients where navigation was used. In two patients, computer navigation had to be abandoned and the operation was completed under CT and radiological control. The use of computer navigation in musculoskeletal oncology allows accurate identification of the local anatomy and can define the extent of the tumour and proposed resection margins. Furthermore, it helps in reconstruction of limb length, rotation and overall alignment after resection of an appendicular tumour. . Cite this article: Bone Joint J 2015;97-B:258–64

The surgical management of musculoskeletal tumours is a challenging problem, particularly in pelvic and diaphyseal tumour resection where accurate determination of bony transection points is extremely important to optimise oncologic, functional and reconstructive options. The use of computer assisted navigation in these cases could improve surgical precision. We resected musculoskeletal tumours in fifteen patients using commercially available computer navigation software (Orthomap 3D). Of the eight pelvic tumours, three underwent biological reconstruction with extra corporeal irradiation; three endoprosthetic replacement (EPR) and two required no bony reconstruction. Four diaphyseal tumours had biological reconstruction. Two patients with proximal femoral sarcoma underwent extra-articular resection and EPR. One soft tissue sarcoma of the adductor compartment involving the femur was resected with EPR. Histological examination of the resected specimens revealed tumour free margins in all cases. Post-operative radiographs and CT show resection and reconstruction as planned in all cases. Several learning points were identified related to juvenile bony anatomy and intra-operative registration. The use of computer navigation in musculoskeletal oncology allows integration of local anatomy and tumour extent to identify resection margins accurately. Furthermore, it can aid in reconstruction following tumour resection. Our experience thus far has been encouraging

The surgical management of musculoskeletal tumours is a challenging problem, particularly in pelvic and diaphyseal tumour resection where accurate determination of bony transection points is extremely important to optimise oncologic, functional and reconstructive options. The use of computer assisted navigation in these cases could improve surgical precision and achieve pre-planned oncological margins with improved accuracy. We resected musculoskeletal tumours in ten patients using commercially available computer navigation software (Orthomap 3D, Stryker UK Ltd). Of the five pelvic tumours, two underwent biological reconstruction with extra corporeal irradiation, two endoprosthetic replacement (EPR) and one did not require bony reconstruction. Three tibial diaphyseal tumours had biological reconstruction. One patient with proximal femoral sarcoma underwent extra-articular resection and EPR. One soft tissue sarcoma of the adductor compartment involving the femur was resected with EPR. Histological examination of the resected specimens revealed tumour free margins in all cases. Post-operative radiographs and CT show resection and reconstruction as planned in all cases. Several learning points were identified related to juvenile bony anatomy and intra-operative registration. The use of computer navigation in musculoskeletal oncology allows integration of local anatomy and tumour extent to identify resection margins accurately. Furthermore, it can aid in reconstruction following tumour resection. Our experience thus far has been encouraging. Further clinical trials are required to evaluate its long-term impact on functional & oncological outcomes

Background. The surgical management of musculoskeletal tumours is a challenging problem, particularly in pelvic and diaphyseal tumour resection where accurate determination of bony transection points is extremely important to optimise oncologic, functional and reconstructive options. The use of computer assisted navigation in these cases could improve surgical precision. Materials and methods. We resected musculoskeletal tumours in fifteen patients using commercially available computer navigation software (Orthomap 3D). Results. Of the eight pelvic tumours, three underwent biological reconstruction with extra corporeal irradiation, three endoprosthetic replacement (EPR) and two required no bony reconstruction. Four diaphyseal tumours had biological reconstruction. Two patients with proximal femoral sarcoma underwent extra-articular resection and EPR. One soft tissue sarcoma of the adductor compartment involving the femur was resected with EPR. Histological examination of the resected specimens revealed tumour free margins in all cases. Post-operative radiographs and CT show resection and reconstruction as planned in all cases. Several learning points were identified related to juvenile bony anatomy and intra-operative registration. Discussion. The use of computer navigation in musculoskeletal oncology allows integration of local anatomy and tumour extent to identify resection margins accurately. Furthermore, it can aid in reconstruction following tumour resection. Our experience thus far has been encouraging

The outcome for patients with Ewing's sarcoma recurrence is poor. Local recurrences occur in 8%-25%of these patients. The aim of the study was to analyze the patients who had a local recurrence to identify factors predicting the local recurrence and if it could be prevented. Methods. A retrospective analysis of 650 patients who had a diagnosis of Ewing's sarcoma treated between 1975 and 2009 at a single institution was performed and 64 patients (10%) who had a local recurrence were identified and analysed. Results. Fifteen patients had metastases at diagnosis.20 patients had chemotherapy and radiotherapy only while 44 had chemotherapy and surgery +/− post op radiotherapy. Thirteen patients who were suitable for post –operative radiotherapy could not receive the treatment due to various reasons like biological reconstruction. The estimated 5 years survival for the patients was 15%. The risk of local recurrence is higher if the tumour is located in the axial skeleton, treatment with chemotherapy and radiotherapy alone [location and size of the tumour precluding surgery]. The risk of local recurrence is higher if the tumour was in the fibula or radius. One out of three patients who have good response to chemotherapy still went on to develop a LR. The use of biological reconstruction and younger age group often resulted in deferral of post-operative radiotherapy. Location and type of treatment can predict LR. Surgery with clear margins and post-operative radiotherapy given when indicated may reduce the incidence of LR

Introduction. The use of computer navigation has a potential to allow precise tumour resection and accurate reconstruction of the resultant defect. This can be useful in difficult areas such as pelvis, diaphyseal (intercalary) resections and geometric bony resections. Methods. We have carried out resections of musculoskeletal tumours in 7 patients using an existing commercial computer navigation system (Orthomap 3D). CT & MRI scans of each patient were fused preoperatively using navigation software and the tumour margins were marked. The planes of tumour resection were defined on the 3D image generated. During surgery, trackers were attached to bone with tumour and registration performed. Instruments attached to navigation tracker were then used to identify the predetermined resection points. Of the 4 pelvic tumours, 1 had biological reconstruction with extra corporeal irradiation, 3 had endoprosthetic replacement & 1 did not need any bony reconstruction. 1 patient with proximal femur tumour needing extraarticular resection had endoprosthetic replacement. The 2 tibial diaphyseal tumours had biological reconstruction. Results. Examination of the resected specimens revealed tumour free margins. Postoperative radiographs showed resection and reconstruction as planned in all cases. In the patient with extraarticular proximal femur resection the hip joint was inadvertently exposed whilst making the acetabular osteotomy & in one patient with pelvic tumour the intra-operative registration could not be accurately performed as she was overweight and a real time matching of anatomy & virtual images was not achieved. Discussion and Conclusion. The use of computer navigation in musculoskeletal oncology allows integration of local anatomy and tumour extent and thus resection margins can be identified accurately. Our experience so far has been encouraging. Further clinical trials (multicentre) are required to evaluate its long term impact including functional & oncological outcomes