Aim. External fixator knee arthrodesis is a salvage procedure mainly used in cases of end-stage infected total knee replacement (iTKR). A stable fixation combined with bone-ends compression is basic to achieve knee fusion in such a scenario but providing enough stability can be challenging in the presence of severe bone loss after multiple previous procedures. Compared with monoplanar configuration, a biplanar frame achieves improved coronal stiffness, while providing the advantages of good access to the wound and allowance of early ambulation. Our primary hypothesis stated that a biplanar frame would achieve higher and quicker fusion rate than a monolateral configuration. Method. We conducted a retrospective cohort study examining patients managed with biplanar external fixator knee fusion due to non-revisable iTKR between 2014 and 2018. We compared this group of patients with a historical cohort-control patient who had been previously published by our unit in 2013, since we switched from a monoplanar to a biplanar configuration for the management of this kind of complex end-stage iTKR. Primary end-points were fusion rate, time to achieve bone fusion and infection eradication rate. Limb-length discrepancy, pain level, patient satisfaction, and health-related quality of life were also evaluated. Results. A total of 29 cases were finally included; 8 patients were managed with a bilateral external fixator and 21 patients were managed with a monoplanar external fixator. In the biplanar configuration group, infection was eradicated in 100% of the patients, and fusion was achieved in all cases after 5.24 months on average. In comparison, in the monolateral configuration group, infection was eradicated in 18 (86%) out of 21, whereas fusion was achieved in 17 (81%) of the patients after a mean of 10.3 months (range, 4–16). Such difference was statistically significant (p<0.05). In both groups, postoperative pain was mild (VAS score 2,25 and 3,4, respectively) and patients expressed a high degree of satisfaction once fusion was achieved. Conclusions. External fixation knee fusion is a useful limb-salvage procedure in end-stage cases of knee PJI. According to our data, the use of a biplanar configuration allows us to reduce in half (10.3 vs 5.2 months, p<0.05) the time needed to achieve the solid bone fusion in such a complex scenario. In this cohort of previously multi-operated patients, the satisfaction is high, and the level of pain is low if a solid bone fusion free of infection is achieved

Paediatric bone sarcomas around the knee are often amenable to either endoprosthetic reconstruction or rotationplasty. Cosmesis and durability dramatically distinguish these two options, although patient-reported functional satisfaction has been similar among survivors. However, the impact on oncological and surgical outcomes for these approaches has not been directly compared. We retrospectively reviewed all wide resections for bone sarcoma of the distal femur or proximal tibia that were reconstructed either with an endoprosthesis or by rotationplasty at our institution between June 2004 and December 2014 with a minimum two year follow-up. Pertinent demographic information, surgical and oncological outcomes were reviewed. Survival analysis was performed using the Kaplan-Meier method with statistical significance set at p<0.05. Thirty eight patients with primary sarcomas around the knee underwent wide resection and either endoprosthetic reconstruction (n=19) or rotationplasty (n=19). Groups were comparable in terms of demographic parameters and systemic tumour burden at presentation. We found that selection of endoprosthetic reconstruction versus rotationplasty did not impact overall survival for the entire patient cohort but was significant in subgroup analysis. Two-year overall survival was 86.7% and 85.6% in the endoprosthesis and rotationplasty groups, respectively (p=0.33). When only patients with greater than 90% chemotherapy-induced necrosis were considered, overall survival was significantly better in the rotationplasty versus endoprosthesis groups (100% vs. 72.9% at two years, p=0.013). Similarly, while event-free survival was not affected by reconstruction method (60.2% vs. 73.3% at two years for endoprosthesis vs rotationplasty, p=0.27), there was a trend towards lower local recurrence in rotationplasty patients (p=0.07). When surgical outcomes were considered, a higher complication rate was seen in patients that received an endoprosthesis compared to those who underwent rotationplasty. Including all reasons for re-operation, 78.9% (n=15) of the endoprosthesis patients required a minimum of one additional surgery compared with only 26.3% (n=5) among rotationplasty patients (p=0.003). The most common reasons for re-operation in endoprosthesis patients were wound breakdown/infection (n=6), limb length discrepancy (n=6) and periprosthetic fracture (n=2). Excluding limb length equalisation procedures, the average time to re-operation in this patient population was 5.6 months (range 1 week to 23 months). Similarly, the most common reason for a secondary procedure in rotationplasty patients was wound breakdown/infection, although only two patients experienced this complication. Average time to re-operation in this group was 23.8 months (range 5 to 49 months). Endoprosthetic reconstruction and rotationplasty are both viable limb-salvage options following wide resection of high-grade bony sarcomas located around the knee in the paediatric population. Endoprosthetic reconstruction is associated with a higher complication rate and may negatively impact local recurrence. Study of a larger number of patients is needed to determine whether the reconstructive choice affects survival

Background. Distal femoral replacements (DFR) are used in children for limb-salvage procedures after bone tumor surgery. These are typically modular devices involving a hinged knee axle that has peripheral metal-on-polyethylene (MoP) and central metal-on-metal (M-M) articulations. While modular connections and M-M surfaces in hip devices have been extensively studied, little is known about long-term wear or corrosion mechanisms of DFRs. Retrieved axles were examined to identify common features and patterns of surface damage, wear and corrosion. Methods. The cobalt chromium alloy axle components from 13 retrieved DFRs were cleaned and examined by eye and with a stereo microscope up to 1000× magnification. Each axle was marked into 6 zones for visual inspection: the proximal and distal views, and the middle (M-M) and 2 peripheral (MoP) zones. The approximate percentage of the following features were recorded per zone: polishing, abrasion or scratching, gouges or detectable wear, impingement wear (i.e. from non- intentional articulation), discoloration and pitting. Results. In each case, the middle M-M zones showed more damage features compared with peripheral MoP zones. Brown discoloration, presumably due to tribofilm deposits, was the predominant M-M area feature, particularly at the junction between the MoP and M-M zones. Higher magnification showed areas of polishing underlying the discoloration, suggesting repetitive removal of the surface metal and re-deposition of tribofilms (Fig 2B). 9 cases demonstrated reflective patches resembling “thumbprint” or “fish scale” markings, which, under higher magnification, showed signs of scratching and grooving in a radial pattern (Figs 2D, 3A). Pits were occasionally present but appeared to be from third-body damage as signs of corrosion were absent. Features that resembled carbides, sometimes with associated “comet” patterns of scratching were apparent under higher magnification in some areas. The MoP zones showed variable scratching, abrasion and wear polishing. The MoP to M-M junctional areas were demarcated by a distinct band corresponding, in some cases, to a narrow wear groove or gouge. 3 axles showed evidence of severe impingement wear on one proximal end. Discussion. This study of retrieved axle components demonstrated varying types of surface wear damage but no clear evidence of corrosion. This is presumably because these parts are in nearly constant motion during gait. Third-body damage may have resulted from the breakdown of surface carbides, leading to scratching, abrasion and wear polishing under high contact stress. Severe impingement wear presumably occurred after catastrophic damage to the polyethylene bushings, allowing eccentric loading and extensive metal wear. The components were revised for a range of clinical reasons including aseptic loosening and the need to expand the prosthesis during growth. With the exception of the few cases with severe impingement, it is unlikely that the wear features seen here contributed to the need for revision. While it was reassuring that corrosion was not a prominent feature of these modular M-M articulations, retrieval analysis of DFR components should be continued to confirm this finding, better document the in vivo wear processes and point to design features that might be improved for future patients. For any figures or tables, please contact the authors directly

Biological reconstruction techniques after diaphyseal tumour resection have increased in popularity in recent years. High complication and failure rates have been reported with intercalary allografts, with recent studies questioning their role in limb-salvage surgery. We developed a technique in which large segment allografts are augmented with intramedullary cement and fixed using compression plating. The goal of this study was to evaluate the survivorship, complications and functional outcomes of these intercalary reconstructions. Forty-two patients who had reconstruction with an intercalary allograft following tumour resection between 1989 and 2010 were identified from our prospectively collected database. Allograft survival, local recurrence-free, disease-free and overall survival were assessed using the Kaplan-Meier method. Patient function was assessed using the Musculoskeletal Tumour Society (MSTS) scoring system and the Toronto Extremity Salvage Score (TESS). The 23 women and 19 men had a mean age of 33 years (14–77). The most common diagnoses were osteosarcoma (n=16) and chondrosarcoma (n=9). There were 9 humerus, 18 femur and 15 tibia reconstructions. At a mean follow-up of 95 months (5–288), 31 patients were alive without disease, 10 were dead of disease and 1 was deceased of other causes. There were 4 local recurrences and 11 patients developed metastatic disease. 5-year local recurrence free survival was 92%, 5-year disease-free survival was 70% and overall survival was 75%. Fourteen of 42 patients (33%) experienced complications: 5 wound healing complications, 4 infections, 2 non-unions, 2 fractures and 1 nerve palsy. Four allografts (9.5%) were revised for complications and 2 (5%) for local recurrence. Mean allograft survival was 85 months (4–288). Mean time to union was 8.2 (3–36) months for the proximal osteotomy site and 8.1 (3–23) months for the distal osteotomy site. The mean score for MSTS 87 was 29.4 (+/− 4.4), MSTS 93 was 83.7 (+/−14.8) and TESS was 81.6 (+/−16.9). An intercalary allograft augmented with intramedullary cement and compression plate fixation provides a reliable and durable method of reconstruction after tumour resection. Complication rates are comparable to the literature and are associated with high levels of patient function and satisfaction

The purpose of this study is to present a series of soft tissue sarcomas requiring complex vascular reconstructions, and to describe their management and outcomes. Soft tissue sarcomas are rare mesodermal malignancies accounting for approximately 1% of all cancers diagnosed annually. Sarcomas involving the pelvis and extremities are of particular interest to the orthopaedic surgeon. Tumours that encase and invade large calibre vascular structures present a major surgical challenge in terms of safety of excision with acceptability of surgical margins. Technical advances in the fields of both orthopaedic and vascular surgery have resulted in a trend towards limb salvage with vascular reconstruction in preference to amputation. Limb-salvage surgery is now feasible due to the variety of reconstructive options available to the surgeon. Nevertheless, surgery with concomitant vascular reconstruction is associated with higher rates of complications including infection and amputation. We present a case series of soft tissue sarcomas with vascular compromise, requiring resection and vascular reconstruction. We treated four patients (n = 4, three females, and one male) with soft tissue masses, which were found to involve local vascular structures. Histology revealed leiomyosarcoma (n = 2) and alveolar soft part sarcomas (n = 2). Both synthetic graft and autogenous graft (long saphenous vein) techniques were utilised. Arterial reconstruction was undertaken in all cases. Venous reconstruction was performed in one case. One patient required graft thrombectomy at one month post-operatively for thrombosis. We present a series of complex tumour cases with concomitant vascular reconstructions drawn from our institution's experience as a national tertiary referral sarcoma service

Aims. Present the outcomes of those patients diagnosed with Ewing's Sarcoma of the foot within the past 10 years and treated at the Royal National Orthopaedic Hospital's Bone Tumour Unit, Stanmore. Methods. Retrospective study of the cases identified from the pathology database. Notes reviewed for presentation, treatment and follow up. TESS (Toronto Extremity Salvage Score) and MSTS (Musculoskeletal tumour score) were calculated. Results. 6 patients identified with positive diagnosis of Ewing's Sarcoma of the Foot. Male:Female ratio of 5:1. Age range 15–31 (Mode 25). 4 cases skeletal, 2 extra skeletal. All cases reviewed by supra-regional MDT and received adjuvant and neo-adjuvant chemotherapy. All except one patient underwent limb-salvage surgery. The MDT decision for the remaining patient was that amputation was the only viable surgical option but the patient and his parents requested radiotherapy without surgical treatment. Mean survival 40 months (15–107 months). All patients survive at time of submission. Mean MSTS/TESS scores 93% (80–100%) and 94.6% (85–100) respectively. Discussion. All patients reported a delay between first presentation and referral to the sarcoma unit. This experience is common across the literature for this rare pathology. Lowest scores were submitted by the two patients who had amputation of their great toe. All patients are happy with their outcome and decision to salvage their limb. All patients scored themselves as “not at all disabled” and two stated this would not have been their response if they had lost their foot. Conclusion. Amputation is psychologically difficult to accept and patients are more receptive to limb salvage surgery. Our patients demonstrate good functional outcome. Our experience at Stanmore suggests that limb salvage surgery with adequate MDT surveillance for Ewing's Sarcoma of the Foot can be a viable alternative to amputation

Introduction. Historically, amputation or rotationplasty were the treatment of choice in skeletally immature patients. The introduction of expandable endoprostheses in the late 1980s offered the advantages of limb-salvage and limb length equality at skeletal maturity and a promising alternative with improved cosmetic results and immediate weight bearing. Objective. to describe the Rizzoli experience in reconstruction with three different types of expandable prostheses in growing children with malignant bone tumors of the femur, assess the outcome of limb salvage in these patients, analyze survival and complications related to these prostheses used over time. Materials and Methods. Between 1996 and 2010, 39 expandable implants were used in 32 children (16 boys and 16 girls; mean age, 9 years at initial surgery) with bone sarcomas of the femur treated with limb salvage using expandable prostheses. The most common diagnosis was osteoblastic osteosarcoma; all children were classified as having a stage IIB lesion and had preoperative and postoperative chemotherapy. The minimally invasive Kotz Growing prosthesis was used in 17 cases (10 primary implant and 7 revision after failure of non-invasive Repiphysis®), the non-invasive Repiphysis® in 15 cases and Stanmore® expandable prostheses in 7 cases. The mean follow-up was 48 months. Functional evaluation and survival analysis of the children and implants were performed. Results. The rate of implant-related complications was 51.3%; 9 prostheses (23%) were revised because of aseptic loosening, infection and breakage. The mean total lengthening was 26 mm (4 to 165 mm) achieved by 78 procedures (2.4 procedures/patient). Three of the nine children who reached skeletal maturity had limb length equality and six discrepancy of 15–30 mm. The survival of the children was 94% and 76% at 24 and 72 months. The survival of the primary prostheses was 90% and 70% at 24 and 72 months. Survival was significantly higher only for the Kotz compared to the Repiphysis® prostheses (p= 0.026). The mean MSTS score was excellent (79%) without a significant difference between the type of prostheses (p= 0.934). Conclusions. In the growing children expandable prostheses are viable reconstruction options with good and excellent oncological and functional outcome, and limb-length equality at skeletal maturity. Mechanical failures including aseptic loosening and breakage, dysfunction of the expansion mechanism, contractures especially around the knee, dislocation and infection were the most common; some designs have been associated with an unacceptably high inherent risk of complications. However, the non-invasive systems are associated with high complications and failure rates. Early experience is promising, but further study is warranted to determine long-term structural integrity of these newer designs