Objectives. We evaluated the accuracy of augmented reality (AR)-based navigation assistance through simulation of bone tumours in a pig femur model. Methods. We developed an AR-based navigation system for bone tumour resection, which could be used on a tablet PC. To simulate a bone tumour in the pig femur, a cortical window was made in the diaphysis and bone cement was inserted. A total of 133 pig femurs were used and tumour resection was simulated with AR-assisted resection (164 resection in 82 femurs, half by an orthropaedic oncology expert and half by an orthopaedic resident) and resection with the conventional method (82 resection in 41 femurs). In the conventional group, resection was performed after measuring the distance from the edge of the condyle to the expected resection margin with a ruler as per routine clinical practice. Results. The mean error of 164 resections in 82 femurs in the AR group was 1.71 mm (0 to 6). The mean error of 82 resections in 41 femurs in the conventional resection group was 2.64 mm (0 to 11) (p < 0.05, one-way analysis of variance). The probabilities of a surgeon obtaining a 10 mm surgical margin with a 3 mm tolerance were 90.2% in AR-assisted resections, and 70.7% in conventional resections. Conclusion. We demonstrated that the accuracy of tumour resection was satisfactory with the help of the AR navigation system, with the tumour shown as a virtual template. In addition, this concept made the navigation system simple and available without additional cost or time. Cite this article: H. S. Cho, Y. K. Park, S. Gupta, C. Yoon, I. Han, H-S. Kim, H. Choi, J. Hong. Augmented reality in bone tumour resection: An experimental study. Bone Joint Res 2017;6:137–143

INTRODUCTION. Bone tumour resection and subsequent reconstruction remains challenging for the surgeon. Obtaining adequate margins is mandatory to decrease the risk of local recurrence. Improving surgical margins quality without excessive resection, reducing surgical time and increasing the quality of the reconstruction are the main goals of today's research in bone tumour surgical management. With the outstanding improvements in imaging and computerised planning, it is now a standard. However, surgical accuracy is essential in orthopaedic oncologic surgery (Grimmer 2005). Patient specific instruments (PSI) may greatly improve the surgeon's ability to achieve the targeted resection. Thanks to its physical support, PSI can physically guide the blade yielding to a better control over the cutting process (Wong, 2014). Surgical time might significantly be reduced as well when compared to conventional method or navigated procedure. Finally, reconstruction may gain in rapidity and quality especially when allograft is the preferred solution as PSI can be designed as well for allograft cutting (Bellanova, 2013). Since 2011, PSI have systematically been used in our institution for bone tumour resection and when applicable allograft reconstruction. This paper reports the mid- to long-term medical outcomes on a large series. MATERIALS AND METHODS. Between 2011 and 2016, we systematically used PSI to remove bone tumours in 30 patients. The pre-operative planning involved the tumour delineation drawn on MRI by the surgeon. The MRI and obtained tumour volume were transferred to the CT-scan by image fusion (co- registration). Cutting planes were positioned around the tumour including a safe margin. The PSI were designed to ensure a sufficient stability but kept thin enough to limit the bone exposure. The PSI was manufactured by 3D-printing in a biocompatible and sterilisable material. PSI has been intraoperatively to cut the bone with predetermined margins. Medical files were reviewed for large data collection: type, size and site of the tumour, pre-and post-operative metastatic status, bone and soft tissues resection margins, local recurrence, use of an allograft and a PSI for graft adjustment or not for the reconstruction, the fusion of the allograft when applicable, the follow-up time and early/late complications. RESULTS. Over a period of 5 years, 30 patients were operated on with PSI (10 osteosarcomas, 4 chondrosarcomas, 10 Ewing sarcomas and 6 other types of bone tumours). Mean follow-up was 27±20 months. 18 cases out of 30 have more than 2 years follow-up and 13 out of 30 have more than 3 years of follow-up. Mean operating time was 6h02±3h44. Mean size of the tumours was 8,4±4,7cm and location was the upper limb in 5 cases, inferior limb in 15 cases and the pelvis in 10 occurrences. Metastatic disease developed postoperatively in 5 patients. Surgical margins in the bone were R0 in all cases but one case where a R1 surgery was planned to preserve a nerve root. We did not observe any local recurrence in the bone. Within soft tissues, margins were classified as R0 in 28 patients and R1 in 2 patients. In 26 cases, an allograft was used to reconstruct the bone defect. In 23 of those patients, the allograft was selected by CT scan and cut using a PSI. In the 3 allografts cut free-handily, only one demonstrated a fusion. Of the 23 cut with a guide, 12 fused completely, 2 demonstrated a partial fusion and 9 were not fused at the last follow-up. At the last follow-up, 2 patients were dead of disease, 5 were alive with metastatic disease and 23 were alive without disease. DISCUSSION. Oncology is probably the field where PSI can bring the largest advantage when compared to the conventional procedure. Several papers have reported the use of PSI for bone tumour resection. All of them have shown very promising results on in-vitro experiments (Cartiaux 2014), cadaver experiment (Wong 2012) or small clinical series (Bellanova 2013, Gouin, 2014). None of these papers report a large patient series associated with a clinically relevant follow-up. This series is the first mid- to long-term follow-up series involving PSI tumour surgery. These results are showing strong evidences of clinical improvements. It comes into contradiction with PSI for total knee arthroplasty where controversial results on the patient's outcome has been reported (Thienpont 2014). R0 margin has been systematically obtained for all bone cuttings, and local recurrence has been strongly decreased (3%) when compared to the usual recurrence rates published in the literature (from 15% to 35% according to the location). Allograft fusion seems improved as well thanks to the shape-matching of the selected allograft and a close contact between host and allograft at bony junctions. With a longer follow-up, these evidences should be stronger to definitely make PSI the best option for bone tumour resection

Resecting bone tumours within the pelvis is highly challenging and requires good cutting accuracy to achieve sufficient margins. Computer-assisted technologies such as intraoperative navigation have been developed for pelvic bone tumour resection. Patient-specific instruments have been transposed to tumour surgery. The present study reports a series of 11 clinical cases of PSI-assisted bone tumour surgery within the pelvis, and assesses how accurately a preoperative resection strategy can be replicated intraoperatively with the PSI.

The patient series consisted in 11 patients eligible for curative surgical resection of primary bone tumor of the pelvis. Eight patients had a bone sarcoma of iliac bone involving the acetabulum, two patients had a sacral tumor, and one patient had a chondrosarcoma of proximal femur with intra-articular hip extension. Resection planning was preoperatively defined including a safe margin defined by the surgeon from 3 up to 15 mm. PSI were designed using a computer-aided design software according to the desired resection strategy and produced by additive manufacturing technology. Intraoperatively, PSI were positioned freehand by the surgeon and fixed on the bone surface using K-wires. The standard surgical approach has been used for each patient. Dissection was in accordance with the routine technique. There was no additional bone exposure to position the PSI. Histopathological analysis of the resected tumor specimens was performed to evaluate the achieved resection margins. Postoperative CT were acquired and matched to the preoperative CT to assess the local control of the tumor. Two parameters were measured: achieved resection margin (minimum distance to the tumor) and location accuracy (maximum distance between achieved and planned cuttings; ISO1101 standard).

PSI were quick and easy to use with a positioning onto the bone surface in less than 5 minutes for all cases. The positioning of the PSI was considered unambiguous for all patients. Histopathological analysis classified all achieved resection margins as R0 (tumor-free), except for two patients : R2 because of a morcelised tumour and R1 in soft tissues. The errors in safe margin averaged −0.8 mm (95% CI: −1.8 mm to 0.1 mm). The location accuracy of the achieved cut planes with respect to the desired cut planes averaged 2.5 mm (95% CI: 1.8 to 3.2 mm).

Results in terms of safe margin or the location accuracy demonstrated how PSI enabled the surgeon to intraoperatively replicate the resection strategies with a very good cutting accuracy. These findings are consistent with the levels of bone-cutting accuracy published in the literature. PSI technology described in this study achieved clear bone margins for all patients. Longer follow-up period is required but it appears that PSI has the potential to provide clinically acceptable margins.

Purpose of the study: Transfer of a vascularised fibular is an option after tumour resection to save the limb.

Material and methods: Thirty-eight consecutive cases of malignant bone tumours located in the shaft of long bones of the lower limb were treated with a free transfer of a vascularised fibula. There were 30 femoral localisations and 8 tibial localisations, 32 first-intention transfers and six transfers after failure of an allograft. Mean age at transfer was 11.8 years (range 4.33–22.57). Adapted chemotherapy was associated. The Musculo-skeletal Tumour Society score was noted for the functional assessment. Healing was considered achieved when there was a bone bridge between the transplant and the recipient bone associated with disappearance of the osteotomy line. Outcome was expressed as mean or percentage with the 95% confidence interval. P< 0.05 was considered significant.

Results: Mean follow-up for the 38 patients was 7.56 years (range 0.37–18.4). The mean MSTS was 27.2 (range 20–30).. This mean score was significantly higher (S t = 2.11> 2.04) for vascularised fibular transfer surgery immediately after tumour resection (27.4) than after revision surgery (25.4). The healing rate was 89%. The rate of healing failure of the vascularised free transfer was significantly greater (p=0.005< 0.05) after revision (33%) than after immediate transfer (6%). The rate of good results in the Boer classification was significantly higher for tibial than femoral reconstructions (p=0.006< 0.05), for immediate surgery than revision surgery (p=0.005< 0.05), and for Ewing tumours than for osteosarcoma (p=0.0019< 0.05).

Discussion: Free transfer of a vascularised fibula is a reliable reconstruction technique for bone shaft loss of the lower limb after resection of a malignant bone tumour in children. This is a mutilating surgery with frequent complications but which can save the limb. This reconstruction surgery should be done at the same time as the resection. Healing of the vascularised fibular transplant is more difficult to achieve for femoral reconstructions than tibial reconstruction and there are more complications in the femoral localisation. Femoral reconstructions using a vascularised fibular transplant should be associated with an allograft.

Background

In certain clinical situations, complex local anatomy and limitations of surgical exposure can make adequate and bone tumor ablation, resection and reconstruction very challenging. We wished to review our clinical experience and accuracy achieved with entirely virtually planned single stage tumor ablation/resection and reconstructions.

In order to investigate the efficacy of free vascularised fibular graft (VFG) after bone intercalary tumour resection in tibia, we present our results with a minimum follow-up of 2 years. From 1988 to 2001, 47 patients affected by high-grade tibial sarcoma in 31 cases (66%), and low-grade diesease in 16 cases (34%) were treated in our department. Average age was 19 years (range 5–60 years), with a male/female ratio of 1.35. The average length of tibial resection was 15 cm, while the average length of the fibular graft was 19 cm. In 11 cases (21%) VFG was assembled alone, while in 36 cases (79%) a massive bone allograft was associated to the fibula. Three patients developed a deep infection, treated by amputation in two cases and by graft removal and an Ilizarov device in one case. Minor complications occurred in 28 cases (55%) (stress fractures, wound slough, osteosynthesis breakage), all healed by minor surgery or conservative treatment. At an average follow-up of 108 months (range 24 to 185 months), four patients had died of disease and three were lost to follow-up. Regarding the overall results, the combined group of fibula plus massive allograft showed to be more effective than the group of fibula alone in terms of early weight bearing (6 versus 12 months), while VFG showed intrinsic efficacy in achieving early bony fusion at the osteotomy lines and hypertrophy of the graft in both groups. Furthermore, using the combined assembly the articular surface could be spared in all the trans-epiphyseal resections, while VFG alone appeared to be electively indicated for infected or irradiated fields.

In conclusion, despite the demanding surgical technique, VFG appears to be a long-lasting and definitive biological reconstruction procedure after intercalary tibial resection.

Objectives. Deep bone and joint infections (DBJI) are directly intertwined with health, demographic change towards an elderly population, and wellbeing. The elderly human population is more prone to acquire infections, and the consequences such as pain, reduced quality of life, morbidity, absence from work and premature retirement due to disability place significant burdens on already strained healthcare systems and societal budgets. DBJIs are less responsive to systemic antibiotics because of poor vascular perfusion in necrotic bone, large bone defects and persistent biofilm-based infection. Emerging bacterial resistance poses a major threat and new innovative treatment modalities are urgently needed to curb its current trajectory. Materials and Methods. We present a new biphasic ceramic bone substitute consisting of hydroxyapatite and calcium sulphate for local antibiotic delivery in combination with bone regeneration. Gentamicin release was measured in four setups: 1) in vitro elution in Ringer’s solution; 2) local elution in patients treated for trochanteric hip fractures or uncemented hip revisions; 3) local elution in patients treated with a bone tumour resection; and 4) local elution in patients treated surgically for chronic corticomedullary osteomyelitis. Results. The release pattern in vitro was comparable with the obtained release in the patient studies. No recurrence was detected in the osteomyelitis group at latest follow-up (minimum 1.5 years). Conclusions. This new biphasic bone substitute containing antibiotics provides safe prevention of bone infections in a range of clinical situations. The in vitro test method predicts the in vivo performance and makes it a reliable tool in the development of future antibiotic-eluting bone-regenerating materials. Cite this article: M. Stravinskas, P. Horstmann, J. Ferguson, W. Hettwer, M. Nilsson, S. Tarasevicius, M. M. Petersen, M. A. McNally, L. Lidgren. Pharmacokinetics of gentamicin eluted from a regenerating bone graft substitute: In vitro and clinical release studies. Bone Joint Res 2016;5:427–435. DOI: 10.1302/2046-3758.59.BJR-2016-0108.R1

Introduction. Clear operative oncological margins are the main target in malignant bone tumour resections. Novel techniques like patient specific instruments (PSIs) are becoming more popular in orthopaedic oncology surgeries and arthroplasty in general with studies suggesting improved accuracy and reduced operating time using PSIs compared to conventional techniques and computer assisted surgery. Improved accuracy would allow preservation of more natural bone of patients with smaller tumour margin. Novel low-cost technology improving accuracy of surgical cuts, would facilitate highly delicate surgeries such as Joint Preserving Surgery (JPS) that improves quality of life for patients by preserving the tibial plateau and muscle attachments around the knee whilst removing bone tumours with adequate tumour margins. There are no universal guidelines on PSI designs and there are no studies showing how specific design of PSIs would affect accuracy of the surgical cuts. We hypothesised if an increased depth of the cutting slot guide for sawblades on the PSI would improve accuracy of cuts. Methods. A pilot drybone experiment was set up, testing 3 different designs of a PSI with changing cutting slot depth, simulating removal of a tumour on the proximal tibia (figure 1). A handheld 3D scanner (Artec Spider, Luxembourg) was used to scan tibia drybones and Computer Aided Design (CAD) software was used to simulate osteosarcoma position and plan intentioned cuts (figure 1). PSI were designed accordingly to allow sufficient tumour. The only change for the 3 designs is the cutting slot depth (10mm, 15mm & 20mm). 7 orthopaedic surgeons were recruited to participate and perform JPS on the drybones using each design 2 times. Each fragment was then scanned with the 3D scanner and were then matched onto the reference tibia with customized software to calculate how each cut (inferior-superior-vertical) deviated from plan in millimetres and degrees (figure 3). In order to tackle PSI placement error, a dedicated 3D-printed mould was used. Results. Comparing actual cuts to planned cuts, changing the height of the cutting slot guide on the designed PSI did not deviate accuracy enough to interfere with a tumour resection margin set to maximum 10mm. We have obtained very accurate cuts with the mean deviations(error) for the 3 different designs were: [10mm slot: 0.76±0.52mm, 2.37±1.26°], [15mm slot: 0.43±0.40mm, 1.89±1.04°] and [20mm: 0.74±0.65mm, 2.40±1.78°] respectively, with no significant difference between mean error for each design overall, but the inferior cuts deviation in mm did show to be more precise with 15mm cutting slot (p<0.05) (figure 2). Discussion. Simulating a cut to resect an osteosarcoma, none of the proposed designs introduced error that would interfere with the tumour margin set. Though 15mm showed increased precision on only one parameter, we concluded that 10mm cutting slot would be sufficient for the accuracy needed for this specific surgical intervention. Future work would include comparing PSI slot depth with position of knee implants after arthroplasty, and how optimisation of other design parameters of PSIs can continue to improve accuracy of orthopaedic surgery and allow increase of bone and joint preservation. For figures/tables, please contact authors directly.

The use of massive endoprostheses following bone tumour resection is well recognised. Where possible, joint salvage rather than joint replacement is usually attempted. However cases arise where there is insufficient bone following tumour resection to allow adequate fixation of a joint sparing prosthesis. We reporta series of 4 patients (aged 4–12), treated between 1994 and 2008, in which irradiated autologous bone has been combined with a diaphyseal or distal femoral replacement in order to preserve the native hip joint. There were 3 cases of osteosarcoma and 1 case of Ewing‘s sarcoma. After a mean follow-up of 53.5 months (range 9–168), all four patients are alive without evidence of local recurrence or metastases. One implant was revised after 14 years following fracture of the extending component of the growing endoprosthesis. There have been no cases of loosening or periprosthetic fracture. This is the first report of irradiated autologous bone with joint sparing endoprostheses in skeletally immature patients

Aims and methods. We present a review of our use of the Ilizarov apparatus in a non-acute NGO hospital in Cambodia specialising in limb reconstruction. Frames are applied without on table image intensification. A retrospective case-note analysis of Ilizarov apparatus use for all indications was conducted. 53 frames were applied between November 2005 and October 2011. Indications for application were chronic open fracture, osteomyelitis, fracture malunion, infective and non-infective non-union, bone lengthening, primary bone tumour resection, ankle fusion, congenital deformity or pseudarthrosis, chronic hip dislocation, or a combination of the above. Results. Median delay in presentation was 104 weeks for all indications (range 4–864). Median treatment length was 21 weeks (3–76). The most frequent complication was pin-site infection. This occurred in 18 patients (34%). Return to theatre occurred in 21 patients (40%). Indications were frame adjustment, pin addition or removal, addition of bone graft or re-osteotomy. Failure of union occurred in three patients. These rates are comparable with those published in both Asian and Western literature. Conclusions. Our data demonstrate the versatility of the Ilizarov apparatus and its importance in limb reconstruction in a developing world setting. Our centre relies on it as a cost-effective tool for traditional and novel indications. In our centre the apparatus is applied without x-ray control and is maintained without a dedicated outreach pin-site care programme. Despite this our complication rates are comparable with western literature. We therefore recommend it as a safe and cost-effective tool for use in other developing world settings

The aim of this project is to test the parameters of Patient Specific Instruments (PSIs) and measuring accuracy of surgical cuts using sawblades with different depths of PSI cutting guide slot. Clear operative oncological margins are the main target in malignant bone tumour resections. Novel techniques like patient specific instruments (PSIs) are becoming more popular in orthopaedic oncology surgeries and arthroplasty in general with studies suggesting improved accuracy and reduced operating time using PSIs compared to conventional techniques and computer assisted surgery. Improved accuracy would allow preservation of more natural bone of patients with smaller tumour margin. Novel low-cost technology improving accuracy of surgical cuts, would facilitate highly delicate surgeries such as Joint Preserving Surgery (JPS) that improves quality of life for patients by preserving the tibial plateau and muscle attachments around the knee whilst removing bone tumours with adequate tumour margins. There are no universal guidelines on PSI designs and there are no studies showing how specific design of PSIs would affect accuracy of the surgical cuts. We hypothesised if an increased depth of the cutting slot guide for sawblades on the PSI would improve accuracy of cuts. A pilot drybone experiment was set up, testing 3 different designs of a PSI with changing cutting slot depth, simulating removal of a tumour on the proximal tibia. A handheld 3D scanner (Artec Spider, Luxembourg) was used to scan tibia drybones and Computer Aided Design (CAD) software was used to simulate osteosarcoma position and plan intentioned cuts. PSI were designed accordingly to allow sufficient tumour. The only change for the 3 designs is the cutting slot depth (10mm, 15mm & 20mm). 7 orthopaedic surgeons were recruited to participate and perform JPS on the drybones using each design 2 times. Each fragment was then scanned with the 3D scanner and were then matched onto the reference tibia with customized software to calculate how each cut (inferior-superior-vertical) deviated from plan in millimetres and degrees. In order to tackle PSI placement error, a dedicated 3D-printed mould was used. Comparing actual cuts to planned cuts, changing the height of the cutting slot guide on the designed PSI did not deviate accuracy enough to interfere with a tumour resection margin set to maximum 10mm. We have obtained very accurate cuts with the mean deviations(error) for the 3 different designs were: [10mm slot: 0.76 ± 0.52mm, 2.37 ± 1.26°], [15 mm slot: 0.43 ± 0.40 mm, 1.89 ± 1.04°] and [20 mm: 0.74 ± 0.65 mm, 2.40 ± 1.78°] respectively, with no significant difference between mean error for each design overall, but the inferior cuts deviation in mm did show to be more precise with 15 mm cutting slot (p<0.05). Simulating a cut to resect an osteosarcoma, none of the proposed designs introduced error that would interfere with the tumour margin set. Though 15mm showed increased precision on only one parameter, we concluded that 10mm cutting slot would be sufficient for the accuracy needed for this specific surgical intervention. Future work would include comparing PSI slot depth with position of knee implants after arthroplasty, and how optimisation of other design parameters of PSIs can continue to improve accuracy of orthopaedic surgery and allow increase of bone and joint preservation

The use of massive endoprostheses following bone tumour resection is well recognised. Where possible, joint salvage rather than joint replacement is usually attempted. However cases arise where there may be insufficient bone stock following tumour resection to allow fixation of a joint sparing prosthesis. We report a series of 4 patients (age4–12) treated between 1994 and 2008, in which irradiated autologous bone has been combined with a diaphyseal or distal femoral replacement in order to preserve the native hip joint. There were 3 cases of osteosarcoma and 1 cases of Ewings sarcoma. After a mean follow up of 53 months (range 9–168) all patients had survived without evidence of local recurrence or metastases. One implant was revised after 14 years following fracture of the extending component of the growing endoprosthesis. There have been no cases of loosening or peri-prosthetic fracture. This is the first report of irradiated autologous bone with joint sparing endoprostheses in the skeletally immature patient. Introduction: Reconstruction of segmental skeletal defects after malignant bone tumour removal has been a topic of much debate. Autoclaved or irradiated autologous bone used in the treatment of malignant bone tumours of the proximal femur in skeletally mature patients has been well reported with a high incidence of fracture and non-union. On follow up, our series of skeletally immature patients showed excellent osteo-integration with native bone and allowed preservation of the native hip joint. Results: We review survival of the patient, implant, any complication and the presence of disease progression

Introduction. Following bone tumour resection, lower limb reconstruction results in leg-length discrepancy in skeletally immature patients. Previously, minimally invasive endoprostheses have been associated with a high risk of complications including joint stiffness, nerve injury, aseptic loosening and infection. The purpose of this study was to examine the outcome of the Stanmore non-invasive extendible endoprostheses used in our institution between 2002 and 2009 and compare them with implants used in the past. Methods. Fifty-five children with a mean age of 11.4 years (5 to 16) underwent limb reconstruction with thirty-three distal femoral, two total femoral, eight proximal femoral and twelve proximal tibial implants. Forty-six endoprostheses were lengthened in clinic without anaesthesia using the principle of electromagnetic induction. Patients were assessed using the Musculoskeletal Tumour Society Score (MSTS) and the Toronto Extremity Salvage Score (TESS). Results. Ten children (18.2%) died of disseminated disease. One child underwent amputation for infected prosthesis. Forty-four patients were reviewed after a mean follow-up of 41 months (16 to 98). The mean MSTS score was 80.7% (26.7-100) and the TESS score was 92.3% (55.2-99). There was no local tumour recurrence. Complications developed in sixteen patients (29.1%). Seven patients (12.7%) underwent ten revision procedures. The mean length gained per patient was 38.6mm (3.5 to 161.5) requiring a mean of 11.3 (1-40) extensions. Ten component exchanges were performed in nine patients (16.4%) after attaining the maximum lengthening capacity of the implant. Eleven patients (20%) were skeletally mature at follow-up, of which ten had equal leg-lengths and nine had full range of hip and knee movement. Overall our outcomes compared favourably with minimal endoprostheses and other non-invasive designs. Discussion. This is the largest reported series of non-invasive extendible endoprostheses, demonstrating good functional outcome with prevention of limb-length discrepancy at skeletal maturity

Introduction. Primary bone tumours of the distal radius are rare, while it remains the third commonest site for primary lesions and recurrences of Giant Cell Tumours (GCT). The functional demands on the hand make reconstruction of the wrist joint following the excision of distal radius, particularly challenging. Methods. A single-centre retrospective study, reporting the functional and oncological outcomes of six patients (4 males, 2 females - mean age of 53 (22 to 79)) who underwent a custom-made endoprosthetic replacement of the distal radius with arthrodesis at our institution, during 1999 - 2010. Five patients were diagnosed with primary bone sarcoma of the distal radius (4 GCTs, 1 osteosarcoma) and another had a metastatic lesion from a primary renal cell carcinoma. The diagnosis was confirmed by needle biopsy in all cases. We assessed the patients' functional outcomes using the Musculoskeletal Tumour Society scoring system (MSTS) and the Toronto Extremity Salvage Score (TESS). Results. The mean follow-up was 3 years (up to 9.5 years). One patient died of unrelated medical causes, age 89, and one patient succumbed to renal carcinoma, age 53 (9.5 and 4 years post-operatively). All prostheses remained clinically and radiologically stable. One-year radiographs confirmed bone remodelling and osseointegration at the bone-prosthesis interface. There were no cases of local recurrence, metastases, infection or wound complications post-operatively. The mean functional outcome scores were: MSTS 73% (71 to 78), TESS 75% (73 to 79). Pain-free hand movements were restored in all cases. Discussion. Reconstruction options include curettage with/without grafting or cementing, ulna translocation, autografts (vascularised or non-vascularised ⊞/⊟ arthrodesis), allografts, custom-made megaprostheses. Custom-made endoprosthetic reconstruction of the distal radius with wrist arthrodesis following bone tumour resection represents a viable and versatile treatment option. Satisfactory outcomes are achieved with acceptable risks and functional outcomes; especially when considering the nature of the diagnosis and alternative treatment options

Introduction. Three-dimensional preoperative planning and bone tumour resection by navigation have been used in the past ten years. According to literature this workflow increases the surgical “accuracy”. However, there are a few and not completely clear reports describing accuracy in preoperative planning and navigation. The objective of this preliminary study was to determine the accuracy of osteotomies planned and guided by navigation in pelvis tumour resection. We assume that the surgical specimen scanned and 3D reconstructed is an acceptable method to determine the accuracy qualitatively and quantitatively of a virtual planning and navigation surgical workflow. Materials and Methods. A total of four patients were evaluated between May 2010 and February 2011, age range: 6–38, 17.4 mean; 2 males and 2 females. There were 4 malignant tumours: Malignant Schwannoma (1), Ewing's tumor (1) and Chondrosarcoma (2). All anatomic regions compromised by the tumour were preoperatively CT scanned (Mutislice 64, Aquilion, Toshiba Medical Systems, Otawara, Japan). Magnetic resonance images (MRI) of the corresponding region were acquired using a 1.5-T unit (Magnetom Avanto, Siemens Medical Solutions, Erlangen, Germany). Image fusion was applied to CT and MRI studies in order to determine the bone cortex and the intra-extraosseous soft tissues tumour extension. Once the fusion was obtained osteotomies were planned, taking into account the tumour extension in a three-dimensional virtual scenario. All patients were planned for two uniplanar osteotomies (intercalary resection). The minimal margin was determined in each plane by measuring the closest distance between malignant tumour and osteotomy plane. These studies allowed the visualisation of the tumour and the application of a virtual osteotomy. The simulation was carried out by using a computer-aided design (CAD) software, Mimics (Materialise, Leuven, Belgium). Three-dimensional preoperative planning was obtained in CAD format. Next, 3D models were exported to CT data sets in Digital Imaging and Communications in Medicine (DICOM) format and uploaded to the navigation system (3D OrthoMap navigation software v1.0, Stryker Navigator, Freiburg, Germany). Using the standard navigation tools (navigated pointer, camera and infrared tracker devices applied to the patient) the surgeon was able to establish a correspondence in a computer monitor between 3D images and real bone. Once osteotomies were performed, the tumour surgical specimen obtained was CT scanned and 3D reconstructed similarly to what was done previously to surgery to CT images acquired with the preoperative protocol in patients. Results. The correlation between the osteotomies preoperatively planned and the osteotomies achieved by navigation was in a global mean of 0.73 millimeters (SD: 3.14) in a total of 6 planes evaluated. Conclusion. According to clinical relevance, this work shows an acceptable accuracy in preoperative planning and navigation. Furthermore, we demonstrate the usefulness of three-dimensional models of surgical specimens when surgeons need to determine quantitative and qualitative accuracy of 3D planning and navigation procedures

The reconstruction of a skeletal defect after resection of a bone tumour represents a challenge for the orthopaedic surgeon. Age, site of the lesion and extension of the disease often limit the choice of surgical technique for a conservative procedure, but several options are available, mainly modular, composite or custom prostheses, massive bone allografts with or without autologous vascularised fibular grafts (AVF), and arthrodeses. An interesting reconstructive technique uses the AVF graft, with microsurgical technique, alone or associated with a massive allograft. The association of a fibular transplant with an allograft increases the mechanical strength of the reconstruction, also promoting more rapid integration. The fibula is a cortical bone and it may provide mechanical strength in the reconstruction of a large segmental bony defect if employed as a viable biological rod. In the present paper the authors discuss their experience with 17 patients treated at the Oncological Orthopaedic Unit of the G.Pini Orthopaedic Institute, for bone tumour resection and reconstruction using AVF graft, almost always combined with a bone allograft. No treatments were performed as augmentation in osteoarticular massive allografts. Subjects’ ages ranged from 7 to 66 years (mean 25.2 years). Most of the patients were referred for a diagnosis of malignancy (15 of 17 cases) and in only two patients were the tumours not aggressive. In 11 patients the AVF was transplanted immediately after tumour resection, while in the others it was used after problems of previous reconstruction. The authors report two cases of deep infection and four mechanical fractures (all healed after a period of cast immobilisation with or without bone bridging). All the AVF survived and healed with a good functional result for the patients except for two recurrences that required an amputation

Minimally invasive placement of iliosacral screws (SI-screw) is becoming the standard surgical procedure for sacrum fractures. Computer navigation seems to increase screw accuracy and reduce intraoperative radiation compared to conventional radiographic placement. In 2012 an interdisciplinary hybrid operating theatre was installed at the University of Ulm. A floor-based robotic flat panel 3D c-arm (Artis zeego, Siemens, Germany) is linked to a navigation system (BrainLab Curve, BrainLab, Germany). With a single intraoperative 3D scan the whole pelvis can be visualised in CT-like quality. The aim of this study was to analyse the accuracy of SI-screws using this hybrid operating theater. 32 SI-screws (30 patients) were included in this study. Indications ranged from bone tumour resection with consecutive stabilisation to pelvic ring fractures. All screws were implanted using the hybrid operating theatre at the University of Ulm. We analysed the intraoperative 3D scan or postoperative computed tomography and classified the grade of perforation of the screws in the neural foramina and the grade of deviation of the screws to the cranial S1 endplate according to Smith et al. Grade 0 stands for no perforation and a deviation of less than 5 °. Grade 1 implies a perforation of less than 2 mm and a deviation of 5–10°, grade 2 a perforation of 2–4 mm and a deviation of 10–15° and grade 3 a perforation of more than 4 mm and a deviation of more than 15°. All patients were tested for intra- and postoperative neurologic complications and infections. The statistical analysis was executed using Microsoft Excel 2010. 32 SI-screws were implanted in the first 20 months after the hybrid operating theatre had been established in 2012. All 30 patients were included in this study (15 men, 15 women). The mean age was 59 years ±23 (13–95 years). 20 patients received a single screw in S1 (66.7%), 1 patient 2 unilateral screws in S1 and S2 (3.3%), one patient 2 bilateral screws in S1 (3.3%) and 8 patients a single screw stabilising both SI-joints (26.7%). 27 screws showed no perforation (84.4%), 1 screw a grade 1 perforation (3.1%) and 4 screws a grade 2 perforation (12.5%). There was no grade 3 perforation. Furthermore there was no perforation of the neural foramina or the ventral cortex in the axial plane of the SI-screws stabilising one SI-joint (24 screws). Only single SI-screws bridging both SI joints showed a perforation of the neural foramina (37% grade 0, 12.5% grade 1, 50% grade 2, 0% grade 3). In the frontal plane 23 screws (71.9%) showed a deviation of less than 5°. In 5 screws a grade 1 deviation (15.6%) and in 4 screws a grade 2 deviation (12.5%) could be found. There was no grade 3 deviation. There were no infections or neurological complications. The high image quality and large field of view in combination with an advanced navigation system is a great benefit for the surgeon. All SI-screws stabilising only one joint showed completely intraosseous placement. Single SI-screws bridging 2 SI-joints intentionally perforated the neural foramina ventrally in 5 cases because of dysmorphic sacral anatomy. This makes image-guided implantation of SI-screws in a hybrid operating theatre a very safe procedure

Aims: Massive allografts have been widely employed to replace skeletal defects after bone tumour resection. They have major advantages but the major concern is the long term behaviour of the implant. The aim of the present study was to evaluate the incidence of complications in allograft reconstruction and to describe the new techniques to decrease their rate. Methods: The present series includes 68 patients with 70 massive allografts operated from 1996 to 2002. 35 were males and 35 females with an average age of 31 years (4–79). The massive allograft was used as osteoarticular reconstruction in 28 cases, composite in 28, intercalary in 10, knee arthrodesis reconstruction in 3 and scapular replacement in one case. In 7 cases a vascularized fibula was associated. The femur was involved in 23 cases, the humerus in 16 and the tibia in 17, the pelvis in 7, the radius in 3, the scapula in 2 and patella and a finger in 1 case. Results: Infection rate on 68 cases was 6% (4 cases). All infections healed after surgical revision. Two patients were lost at fu and 10 patients have less than 12 months of fu. The 58 patients left have an average fu of 34 months (12–71). Among these patients 45% had one or more complications treated surgically and 2/3 of the cases healed. Non union rate was 12% and fracture rate 5%. Conclusion: Allograft reconstruction showed a high rate of complications. Almost half of the patients (45%) presented one or more complications which required surgery in 40% of cases. Aggressive antibiotic perioperative regimen and adequate soft tissue coverage of the graft may reduce the risk of infections. Biologic augmentation with vascularized grafts, bone marrow and/or growth factors may reduce non union rate. Cement filling of the graft and composite implant (with prosthesis association) have been introduced in order to decrease the risk of diaphyseal and articular fractures

Purpose: The bifoliated vascularised fibula graft is an attractive alternative for reconstruction of large bone segments. The purpose of this work was to evaluate mid-term results and the usefulness of two surgical techniques: skin island flap monitoring and the arterio-venous loop. Material and methods: This retrospective analysis included fourteen patients (eleven men and three women) treated between 1992 and 2002. Mean age was 30 years (10–54). Indications were complications of open fractures in nine patients, major bone loss in two, septic nonunion in four, and aseptic nonunion in three. Reconstruction was performed after bone tumour resection in five patients involving immediate reconstruction after failure of an infected massive allograft in four of them. Localisations were: tibia (n=6), femur (n=5), humerus (n=2), and pelvis (n=1). Average bone loss was 10 cm (7–15 cm). Minimal pinning, cerclage or screwing was used to stabilise the flap completed by internal fixation in four patients and external fixation in ten. A monitoring skin island was used for twelve patients (the island was technically impossible in two patients). Vascular anastomoses were performed in seven patients using an arteriovenous loop, performed as a preliminary measure in six. Results: Mean follow-up was 35 months. One patient died early from tumour progression. Among the seven patients who had an arteriovenous loop, one required revision for a vascular complication. For the seven “classical” bypasses, there were three intraoperative or early complications requiring revision of the anastomoses. Nonunion developed despite early revision in the four patients whose monitoring skin island suffered. Consolidation was achieved without revision in all patients who skin island did not suffer; time to bone healing was eleven months for seven of them. Conclusion: Bone healing was related to the quality of graft vacularisation. Clinical observation of the monitoring island was the best way to identify vascular complications early and initiate treatment. Use of a preliminary arteriovenous loop decreased the risk of vascular insufficiency inherent with long bypasses and shortened operative time

Various kinds of bone have been used as a donor for vascularised bone grafts (VGF) to the upper extremities; among them the fibula has been widely used because of its structural characteristics and low donor site morbidity. Vascularised fibular graft is indicated in patients with large bone defects, bone tumour resection, established or infected non-union, congenital pseudarthrosis, avascular necrosis or bone defects surrounded by scarred, infected and poorly vascularised soft tissue or failure of conventional techniques. Between 1994 and 2003 nine patients were treated with vascularised fibular graft (VFG) and five for reconstruction of upper extremities defects, following trauma of the forearm with failure of conventional treatments. Four were male and one were female; the mean age was 32 years; the reconstructed sites were four radius and one ulna. The mean lengths of the bone defect was 9 cm. All patients were evaluated pre-operatively with angiography and/or magnetic resonance imaging. Two patients had a concomitant arthrodesis of the wrist. The bone graft was stabilised with plates (AO/LCP), screws, K-wires and the forearm was immobilised in plaster or with external fixation for several months. Cancellous iliac bone graft was packed about the proximal and distal junctions. In two recent cases autologous platelet gel was added at the sites of fixation. Bone healing was assessed clinically by the absence of pain and mobility on stress, and radiologically. Patients’ satisfaction and function results were assessed by the DASH questionnaire. After an average duration of follow-up of 48 months (from December 1996 to December 2003), all but one of the patients had radiographic evidence of osseous union of both bone junctions. All wounds healed primarily and no patient had problems related to the donor leg. Three patients had returned to their pre-injury occupation. Vascularised fibula transfer is a valuable technique for the reconstruction of extensive long-bone defects in the upper extremities. The fibula allows a transfer of a bone that is structurally similar to the radius and is of sufficient length for the reconstruction of most skeletal defects in the forearm. In these serious forearm injuries, rapidity of fracture healing is not the primary issue, but rather control of infection and bone stability. The only disadvantage of VFG is that it is more costly; because more technical expertise is required for the microvascular work and the operating time is extended. The reliability and the value of vascularised fibula transfer will increase, with further experience, careful patient selection and appropriate pre and post-operative technical details