Background: Soft tissue sarcomas (STS) in children, adolescents, and young adults are rare and biologically heterogeneous, and prognostic factors for local recurrence, metastasis, and survival remain incompletely defined. This study aimed to characterize oncological outcomes and to explore clinical, surgical, and treatment-related factors associated with these endpoints at a tertiary sarcoma center. Methods: This retrospective single-center cohort study included 42 consecutive patients aged ≤25 years with histologically confirmed STS who underwent definitive surgery between June 2018 and November 2025. Local recurrence-free (LRFS), metastasis-free (MFS), event-free (EFS), and overall survival (OS) were estimated by the Kaplan-Meier method with competing-risks sensitivity analyses. Given the limited number of events, pre-specified univariable comparisons (log-rank, Fisher exact, Mann-Whitney U) were performed and regarded as exploratory. Results: The median age was 16.7 years and 26 patients (61.9%) were female. A microscopically complete (R0) resection was achieved in 35 of 41 patients with assessable margins (85.4%), and limb preservation in 38 (90.5%). Over a median follow-up of 23.1 months, the 24- and 60-month estimates were LRFS 85.7% and 79.6%, MFS 93.3% and 84.8%, EFS 82.3% and 64.7%, and OS 96.0% and 81.5%, respectively. Metastatic disease at diagnosis was the only variable associated with metastatic status at last follow-up (p = 0.035). No factor was robustly associated with local recurrence; anatomical site (p = 0.68), resection-margin status (p = 0.23), and tumor volume (p = 0.97) were not significant, and an apparent association with a sub-millimeter margin rested on a single event (complete separation). Conclusions: Metastatic disease at diagnosis emerged as the most important prognostic factor for MFS in our cohort. Despite the complexity of treatment in this young patient population, high rates of complete resection and limb preservation were achieved, highlighting the value of multidisciplinary management in specialized sarcoma centers. While the limited cohort size did not allow the identification of further statistically significant prognostic factors for local recurrence, such associations may become detectable in larger multicenter studies.

Wound-healing complications (WHCs) remain a significant challenge in soft tissue sarcoma (STS) surgery, contributing to increased morbidity, prolonged hospitalisation, and impaired functional outcomes. This study aimed to identify predictors of WHC development in STS patients to improve therapeutic strategies and patient recovery. We conducted a single-institution, retrospective analysis of 318 STS patients treated between April 2019 and June 2021. Variables assessed included demographic data, tumour characteristics, treatment modalities, surgical interventions, and follow-up outcomes. Statistical analyses used chi-square tests, Kaplan-Meier estimates, and multivariate regression. WHCs occurred in 30.8% of patients. Significant negative predictors included high tumour grade (p = 0.018), presence of metastasis (p < 0.001), bone tissue resection (p = 0.005), number of revision procedures (p < 0.001), secondary wound closure (p < 0.001), and tumour relapse frequency (p = 0.012). WHCs were also associated with increased risk of death (p = 0.004) and longer initial hospitalisation (p < 0.001). Chemotherapy showed a protective effect when stratified by tumour grade. Patients with high-grade tumours and multiple surgical interventions represent a high-risk group for WHC development. These findings highlight the importance of ongoing treatment reevaluation and suggest that chemotherapy may offer beneficial outcomes in selected cases.

Background: The use of augmented reality (AR) in orthopaedics is growing rapidly but is mainly limited to pre-operative planning and teaching. This study is one of the first to describe the intraoperative application within revision arthroplasty for the positioning of customised partial pelvic replacements. Methods: In a proof-of-concept study an AR environment was used during surgery in 11 cases to enhance implant positioning. Postoperatively, a voxel-based CT deviation analysis was carried out to determine the COR deviation and the cup plane deviation angle. Additionally, digital implant superimposition was conducted. Results: Implantation was possible in all cases with a mean COR deviation vector of 4.2 (SD 2.5; 1.2-9.3) mm and a cup plane deviation angle of 4.4 (SD 2.5; 0.7-8.1)°. The implant analysis showed a superimposition of 0.69 (SD 0.15; 0.38-0.88) (Dice-Score calculation). Conclusions: This study is able to report promising results for AR in orthopaedic surgery, showing improved intraoperative feedback in complex operations, resulting in increased accuracy. However, the integration of AR poses a new challenge to the surgical team, especially because the AR users are facing a significantly increased level of intraoperative stress. Further development of this auspicious tool, as well as a conceivable combination with navigation, is necessary to facilitate broader usage.

Background/Objectives: The growing incidence of acetabular revisions has highlighted the importance of achieving reliable fixation to the remaining bone. Proximal transiliac fixation (TIF) of pelvic implants is becoming an increasingly common approach for managing extensive bone defects. This study seeks to provide guidance on TIF implantation by analyzing the optimal screw placement in partial pelvic replacements for acetabular defects. Methods: Between 2014 and 2024, a cohort of 96 consecutive patients (65 females and 31 males) who underwent customized partial pelvic replacement (PPR) with transiliac fixation (TIF) were examined. The angle and entry point of the ideal TIF were determined using preoperative three-dimensional planning and compared with potential influencing factors. Results: All PPRs were successfully implanted, with an average TIF length of 77 mm. The mean anteroposterior angle for TIF was 18° medially and 27° dorsally. Conclusions: Analysis of the entry point showed concentration around the second radius and between the eleven o’clock and one o’clock positions. The AP angle is notably affected by gender and height. Considering the precision of human judgment, a recommendation for TIF placement would be 20° medial and 30° dorsal deviation, with the entry point around the twelve o’clock position and the second ring from the center of the cup.

While the usual etiology of slipped capital femoral epiphysis (SCFE) is idiopathic, there are many other factors that increase the predisposition to slippage. Chemotherapy can be one of them. In this article, we report a rare case of acute SCFE after tumor prosthesis implantation in a patient who received chemotherapy. A 10-year-old girl with osteosarcoma of the right distal femur underwent (neo-) adjuvant chemotherapy, wide tumor resection, and reconstruction using a growing tumor prosthesis and a short non-cemented femoral stem. Half a year after implantation, she developed aseptic loosening. Revision surgery was performed using a hydroxyapatite (HA)-coated cementless femoral stem. Postoperative plain radiographs revealed SCFE that was treated by closed reduction and screw fixation. The patient recovered without complications, and unaffected hip showed no radiographic signs of slippage on follow-up. The forces of implanting a tumor prosthesis, particularly with a non-cemented stem, can increase the risk of an acute SCFE. The controversy over prophylactic pinning of the uninvolved hip in chemotherapy-associated SCFE is unresolved. Pinning can be considered only in the presence of abnormal prodromal radiological findings.

BACKGROUND:Off-the-shelf stems offer a wide variety of fixation methods for revision arthroplasty and intercalary tumour implants. However, in extensive defects or needed resection with minimal bone stock left, solid fixation is often not feasible with these implants. Custom-made stem solutions (CSS) offer a viable alternative in these cases to achieve joint preservation. METHODS:Between 2017 and 2024 14 patients (15 implants) were treated in a single-centre study. CSS were indicated if the remaining bone stock was deemed insufficient for normal stem fixation due to tumour resection or previous operations. Postoperative analysis was conducted to evaluate the functional outcome as well as revision rates. RESULTS:Implantation was possible in all cases, during the follow-up of 30 (SD 18; 6-66) months revision was needed in five cases; with one aseptic loosening, one screw loosening and three PJI cases. Mean MSTS score was 24 (SD 5; 17-30). CONCLUSION:Custom-made stem solutions show promising results in extreme cases. Especially as a preservation of the joint is possible, this treatment algorithm should be considered on a case-by-case basis.

Complications of transcutaneous osseointegrated prosthetic systems (TOPS) focus on the metal-cutaneous interface at the stoma. Besides pain due to scare tissue as well as undefined neuropathic disorders, there is high evidence that the stoma presents the main risk causing hypergranulation and ascending infection. To restore the cutaneous barrier function in this functional area, soft-tissue on- or in-growth providing a vital and mechanically stable bio-artificial conjunction is considered a promising approach. In this study we assessed viability and proliferation of adult human dermal fibroblasts (HDFa) on modifications of a standard prosthetic titanium surface. Un-coated (TiAl6V4) as well as a titanium-nitrite (TiN) coated additive manufactured porous three-dimensional surface structures (EPORE®) were seeded with HDFa and compared to plain TiAl6V4 and polystyrene surfaces as control. Cell viability and proliferation were assessed at 24 h and 7 days after seeding with a fluorescence-based live-dead assay. Adhesion and cell morphology were analyzed by scanning electron microscopy at the respective measurements. Both EPORE® surface specifications revealed a homogenous cell distribution with flat and spread cell morphology forming filopodia at both measurements. Proliferation and trend to confluence was seen on un-coated EPORE® surfaces with ongoing incubation but appeared substantially lower on the TiN-coated EPORE® specification. While cell viability on both EPORE® specifications was comparable to plain TiAL6V4 and polystyrene controls, cell proliferation and confluence were less pronounced when compared to controls. The EPORE® topography allows for fibroblast adhesion and viability in both standard TiAl6V4 and – to a minor degree - TiN-coated specifications as a proof of principle.

Background. Ewing sarcoma (EwS) is a rare and highly malignant bone tumor primarily affecting children, adolescents, and young adults. The pelvis, trunk, and lower extremities are the most common sites, while EwS of the sacrum as a primary site is very rare, and only few studies focusing on this location are published. Due to the anatomical condition, local treatment is challenging in sacral malignancies. We analyzed factors that might influence the outcome of patients suffering from sacral EwS. Methods. We retrospectively analyzed data of the GPOH EURO-E.W.I.N.G 99 trial and the EWING 2008 trial, with a cohort of 124 patients with localized or metastatic sacral EwS. The study endpoints were overall survival (OS) and event-free survival (EFS). OS and EFS were calculated using the Kaplan–Meier method, and univariate comparisons were estimated using the log-rank test. Hazard ratios (HRs) with respective 95% confidence intervals (CIs) were estimated in a multivariable Cox regression model. Results. The presence of metastases (3y-EFS: 0.33 vs. 0.68; P<0.001; HR = 3.4, 95% CI 1.7 to 6.6; 3y-OS: 0.48 vs. 0.85; P<0.001; HR = 4.23, 95% CI 1.8 to 9.7), large tumor volume (≥200 ml) (3y-EFS: 0.36 vs. 0.69; P=0.02; HR = 2.1, 95% CI 1.1 to 4.0; 3y-OS: 0.42 vs. 0.73; P=0.04; HR = 2.1, 95% CI 1.03 to 4.5), and age ≥18 years (3y-EFS: 0.41 vs. 0.60; P=0.02; HR = 2.6, 95% CI 1.3 to 5.2; 3y-OS: 0.294 vs. 0.59; P=0.01; HR = 2.92, 95% CI 1.29 to 6.6) were revealed as adverse prognostic factors. Conclusion. Young age seems to positively influence patients` survival, especially in patients with primary metastatic disease. In this context, our results support other studies, stating that older age has a negative impact on survival. Tumor volume, metastases, and the type of local therapy modality have an impact on the outcome of sacral EwS. Level of evidence: Level 2. This trial is registered with NCT00020566 and NCT00987636.

Resection margin adequacy plays a critical role in the local control of sarcomas. Fluorescence-guided surgery has increased complete resection rates and local recurrence-free survival in several oncological disciplines. The purpose of this study was to determine whether sarcomas exhibit sufficient tumor fluorescence (photodynamic diagnosis (PDD)) after administration of 5-aminolevulinic acid (5-ALA) and whether photodynamic therapy (PDT) has an impact on tumor vitality in vivo. Sixteen primary cell cultures were derived from patient samples of 12 different sarcoma subtypes and transplanted onto the chorio-allantoic membrane (CAM) of chick embryos to generate 3-dimensional cell-derived xenografts (CDXs). After treatment with 5-ALA, the CDXs were incubated for another 4 h. Subsequently accumulated protoporphyrin IX (PPIX) was excited by blue light and the intensity of tumor fluorescence was analyzed. A subset of CDXs was exposed to red light and morphological changes of both CAMs and tumors were documented. Twenty-four hours after PDT, the tumors were excised and examined histologically. High rates of cell-derived engraftments on the CAM were achieved in all sarcoma subtypes and an intense PPIX fluorescence was observed. PDT of CDXs resulted in a disruption of tumor-feeding vessels and 52.4% of CDXs presented as regressive after PDT treatment, whereas control CDXs remained vital in all cases. Therefore, 5-ALA mediated PDD and PDT appear to be promising tools in defining sarcoma resection margins (PDD) and adjuvant treatment of the tumor bed (PDT).

AbstractPurpose: The phase III, open-label, prospective, multicenter, randomized Ewing 2008R1 trial (EudraCT2008-003658-13) was conducted in 12 countries to evaluate the effect of zoledronic acid (ZOL) maintenance therapy compared with no add-on regarding event-free survival (EFS, primary endpoint) and overall survival (OS) in standard-risk Ewing sarcoma (EWS). Patients and Methods: Eligible patients had localized EWS with either good histologic response to induction chemotherapy and/or small tumors (<200 mL). Patients received six cycles of VIDE induction and eight cycles of VAI (male) or eight cycles of VAC (female) consolidation. ZOL treatment started parallel to the sixth consolidation cycle. Randomization was stratified by tumor site (pelvis/other). The two-sided adaptive inverse–normal four-stage design (planned sample size 448 patients, significance level 5%, power 80%) was changed after the first interim analysis using the Müller–Schäfer method. Results: Between April 2010 and November 2018, 284 patients were randomized (142 ZOL/142 no add-on). With a median follow-up of 3.9 years, EFS was not significantly different between ZOL and no add-on group in the adaptive design (HR, 0.74; 95% CI, 0.43–1.28, P = 0.27, intention-to-treat). Three-year EFS rates were 84.0% (95% CI, 77.7%–90.8%) for ZOL vs. 81.7% (95% CI, 75.2%–88.8%) for no add-on. Results were similar in the per-protocol collective. OS was not different between groups. The 3-year OS was 92.8% (95% CI, 88.4%–97.5%) for ZOL and 94.6% (95% CI, 90.9%–98.6%) for no add-on. Noticeable more renal, neurologic, and gastrointestinal toxicities were observed for ZOL (P < 0.05). Severe renal toxicities occurred more often in the ZOL arm (P = 0.003). Conclusions: In patients with standard-risk localized EWS, there is no additional benefit from maintenance treatment with ZOL.

Introduction: As survival rates associated with the multimodal treatment of malignant bone cancer (osteosarcoma and Ewing's sarcoma) are satisfactory, health-related quality of life and the return to activity and sports by the affected patients have attracted increasing attention in recent years. Nowadays, limbs can be salvaged for most patients using modular endoprostheses. Such patients are typically adolescents and young adults who have high activity levels and thereby high demands for multimodal cancer treatment. This study aimed to evaluate the activity levels and sporting proficiencies that can be attained after modular endoprosthetic treatment of bone sarcomas as well as the extent to which physiotherapeutic and sports interventions influence functional outcome and activity levels. Methods: This non-systematic review of the literature focused on the return to activity and sports after modular endoprosthetic treatment of lower extremities bone sarcomas in adolescents and young adults. The electronic database PubMed was screened for relevant publications on this issue. A treatment algorithm for return to activity and sports in tumor orthopaedics is proposed. Results and Discussion: The objective activity level (gait cycles per day and gait intensities) in patients treated for bone sarcomas is reduced in short- and long-term follow-ups compared with healthy controls and patients with other cancers (leukaemia). Although a negative impact is observed in terms of motor performance, it shows improvement over time. Functional assessment at 12 postoperative months is sensible as neoadjuvant chemotherapy is completed by then. In long-term followup, patients with bone sarcomas can achieve high sports activity levels, i. e., type of sport, frequency/week and UCLA score, after modular endoprosthetic reconstruction. The maximum level is attained at 5 years postoperatively. Nevertheless, there is a shift from high- and intermediate- to low-impact sports. Only 20% of the patients participate in school sports regularly without limitations. The localisation of bone sarcoma, but not the rate of postoperative complications, influences the postoperative activity level. Individualised sports-related interventions during and after multimodal treatment can improve the short-term activity levels; moreover, "serious games" can improve motor performance and postural control. There is no evidence that intense activity levels leads to early loosening of the endoprosthesis. There is insufficient valid data on activity and sports after modular endoprosthetic treatment of bone sarcomas of the upper extremities. Conclusion: High preoperative activity levels of young patients with bone sarcomas must be considered in tumour orthopaedics. Limitations on sports activities have a significant negative impact on the quality of life and mental health of such patients. Therefore, tumour orthopaedic treatment has to focus on preserving an improvement in these factors. The overall existing evidence concerning this issue is weak. Additional studies to evaluate the ability to return to specific sports activities are desirable, as well as prospective interventional studies.

Supra-acetabular bone loss close beyond the sciatic notch is one of the most challenging defect types for stable anatomical reconstruction in revision arthroplasty. Using reconstruction strategies from tumour orthopaedic surgery, we adapted tricortical trans-iliosacral fixation options for custom-made implants in revision arthroplasty. The aim of the present study was to present the clinical and radiological results of this extraordinary pelvic defect reconstruction. Between 2016 and 2021, 10 patients with a custom-made pelvic construct using tricortical iliosacral fixation (see Fig. 1) were included in the study. Follow-up was 34 (SD 10; range 15–49) months. Postoperatively CT scans evaluating the implant position were performed. Functional outcome and the clinical results were recorded. Implantation was possible as planned in all cases in 236 (SD 64: range 170–378) min. Correct centre of rotation (COR) reconstruction was possible in nine cases. One sacrum screw crossed a neuroforamen in one case without clinical symptoms. During the follow-up period, four further operations were required in two patients. There were no individual implant revisions or aseptic loosening recorded. The Harris Hip Score increased significantly from 27 Pts. to 67 Pts. with a mean improvement of 37 (p < 0.005). EQ-5D developed from 0.562 to 0.725 (p = 0.038) as a clear improvement in quality of life. Custom-made partial pelvis replacement with iliosacral fixation offers a safe solution in “beyond Paprosky type III defects” for hip revision arthroplasty. Due to meticulous planning, precise implantation with good clinical outcome can be achieved. Furthermore, the functional outcome and patient satisfaction increased significantly showing promising early results with a relatively low complication rate.

Purpose:Radiation therapy (RT) is an integral part of Ewing sarcoma (EwS) therapy. The Ewing 2008 protocol recommended RT doses ranging from 45 to 54 Gy. However, some patients received other doses of RT. We analyzed the effect of different RT doses on event-free survival (EFS) and overall survival (OS) in patients with EwS. Methods and Materials:The Ewing 2008 database included 528 RT-admitted patients with nonmetastatic EwS. Recommended multimodal therapy consisted of multiagent chemotherapy and local treatment consisting of surgery (S&RT group) and/or RT (RT group). EFS and OS were analyzed with uni- and multivariable Cox regression models including known prognostic factors such as age, sex, tumor volume, surgical margins, and histologic response. Results:S&RT was performed in 332 patients (62.9%), and 145 patients (27.5%) received definitive RT. Standard dose ≤ 53 Gy (d1) was admitted in 57.8%, high dose of 54 to 58 Gy (d2) in 35.5%, and very high dose ≥ 59 Gy (d3) in 6.6% of patients. In the RT group, RT dose was d1 in 11.7%, d2 in 44.1%, and d3 in 44.1% of patients. Three-year EFS in the S&RT group was 76.6% for d1, 73.7% for d2, and 68.2% for d3 (P = .42) and in the RT group 52.9%, 62.5%, and 70.3% (P = .63), respectively. Multivariable Cox regression revealed age ≥ 15 years (hazard ratio [HR], 2.68; 95% confidence interval [CI], 1.63-4.38) and nonradical margins (HR, 1.76; 95% CI, 1.05-2.93) for the S&RT group (sex, P = .96; histologic response, P = .07; tumor volume, P = .50; dose, P = .10) and large tumor volume (HR, 2.20; 95% CI, 1.21-4.0) for the RT group as independent factors (dose, P = .15; age, P = .08; sex, P = .40). Conclusions:In the combined local therapy modality group, treatment with higher RT dose had an effect on EFS, whereas higher dose of radiation when treated with definitive RT was associated with an increased OS. Indications for selection biases for dosage were found. Upcoming trials will assess the value of different RT doses in a randomized manner to control for potential selection bias.

BACKGROUND:Local treatment is a crucial element in the standard of care for Ewing sarcoma (EWS). While systemic treatment is improved in randomised clinical trials, local treatment modalities are discussed controversially. We analysed the association between local therapy and event-free survival (EFS), overall survival (OS), and local recurrence (LR) in prospectively collected data of patients with localised EWS. PATIENTS AND METHODS:We analysed data from the international Ewing 2008 study registered between 2009 and 2019 in 117 centres. After induction chemotherapy, patients received surgery, radiotherapy, or a combination thereof. We performed Cox regression, conducted propensity score-weighted sensitivity analysis, and performed subgroup analyses. Hazard ratios (HRs) and 95% confidence intervals are reported. RESULTS:We included 863 patients with localised EWS (surgery alone: 331, combination therapy: 358, definitive radiotherapy: 174). In patients treated with combination therapy compared to surgery alone, EFS HR was 0.84 (0.57-1.24; p = 0.38), OS HR was 0.84 (0.57-1.23; p = 0.41), and LR HR was 0.58 (0.26-1.31; p = 0.19). Hazards of any event were increased in patients treated with definitive radiotherapy compared to surgery only, HR 1.53 (1.02-2.31; p = 0.04). Patients with poor responses to chemotherapy benefitted from combination therapy over definitive surgery with an EFS HR 0.49 (0.27-0.89; p = 0.02). Patients with pelvic tumours benefitted from combination therapy over surgery only regarding LR, HR 0.12 (0.02-0.72; p = 0.02). CONCLUSION:Patients with poor responses to chemotherapy benefitted from radiotherapy added to surgery. In the whole group, radiotherapy alone as opposed to surgery alone increased the hazards of any event.

Background: While off-the-shelf cones and sleeves yield good results in AORI type 2 and 3 defects in revision knee surgery, massive longitudinal defects may require a proximal tibia replacement. To achieve the best anatomical as well as biomechanical reconstruction and preserve the tibial tuberosity, we developed custom-made metaphyseal sleeves (CMSs) to reconstruct massive defects with a hinge knee replacement. Methods: Between 2019 and 2022, 10 patients were treated in a single-center study. The indication for revision was aseptic loosening in five cases and periprosthetic joint infection in five cases. The mean number of previous revisions after the index operations was 7 (SD: 2; 4–12). A postoperative analysis was conducted to evaluate the functional outcome as well as the osteointegrative potential. Results: Implantation of the CMS in rTKA was carried out in all cases, with a mean operation time of 155 ± 48 (108–256) min. During the follow-up of 23 ± 7 (7–31) months, no CMS was revised and revisions due to other causes were conducted in five cases. Early radiographic evidence of osseointegration was recorded using a validated method. The postoperative OKS showed a significant increase (p < 0.001), with a mean score of 24 (SD: 4; range: 14–31). Conclusion: Custom-made metaphyseal sleeves show acceptable results in extreme cases. As custom-made components become more and more common, this treatment algorithm presents a viable alternative in complex rTKA.

Background: The cortical desmoid (DFCI) of the posteromedial femoral condyle is considered an asymptomatic incidental finding in adolescents without clinical relevance. The aim of this study was to evaluate the clinical relevance of DFCI from both a tumor orthopedic and sports medicine point of view. Methods: n = 23 patients (13.74 ± 2.74 years; nineteen female, four male) with DFCI of the posteromedial femoral condyle were included. A localized posteromedial knee pain on exertion was differentiated from non-specific knee pain. Symptom duration, additional pathologies, number of MRIs, sports activity and training intensity, downtime, therapeutic modalities, and relief/remission of symptoms were documented. The Tegner activity scale (TAS) and Lysholm score (LS) were collected. The influence of specific posteromedial pain, MRI presence of paratendinous cysts, sports level as well as physiotherapy on downtime and LS/TAS was statistically analyzed. Results: 100% reported knee symptoms at initial presentation. A localized posteromedial pain was documented in 52%. In 16/23 (70%) additional functional pathologies were diagnosed. Patients were physically highly active with high training intensities (6.52 ± 5.87 h/week) and performance level (65% competitive vs. 35% recreational). Patients underwent 1.91 ± 0.97 MRIs (max four). Symptom duration was 10.48 ± 11.02 weeks. A follow-up examination was performed after 12.62 ± 10.41 months (n = two lost to follow-up). 17/21 had physiotherapy, on average 17.06 ± 13.33 units. Overall downtime was 13.39 ± 12.50 weeks, the return-to-sports (RTS) rate 81%. 100%/38% reported a relief/remission of complaints. LS was 93.29 ± 7.95, median TAS before onset of knee complaints/at follow-up 7 (6–7)/7 (5–7). Specific posteromedial pain, presence of paratendinous cysts, sports level and physiotherapy had no significant influence on downtime and outcome parameters (n.s.). Conclusions: DFCI as a pathognomonic finding is recurrently encountered in the MRIs of children and adolescents. This knowledge is essential to spare patients from overtreatment. Contrary to the literature, the present results implicate a clinical relevance of DFCI particularly in those who are physically highly active with localized pain on exertion. Structured physiotherapy as basic treatment is recommended.

BACKGROUND:The classic type of epithelioid sarcoma (ES) is a rare, aggressive soft tissue neoplasm that most commonly affects the distal upper extremities of young patients. This study aimed to assess clinical features and provide a long-term report of the oncological outcome.METHODS:We retrospectively analyzed our clinical database for patients with ES of the distal upper extremities.RESULTS:Twenty-three patients with ES of the distal upper extremity were treated surgically between January 1990 and August 2018. ES affected most commonly the palmar side of young patients. The most common site affected by a sarcoma was the wrist in 47.8% of cases, followed by metacarpals and fingers with 34.8% and 17.4%, respectively. Most of the patients were treated according to the protocols of interdisciplinary tumor boards with multimodal therapy. A local recurrence was observed in 7 patients (30.4%). The 5 - and 10-year recurrence-free survival was 80.4% (95% confidence interval [CI]: 68.6-76.8) and 60.9% (95% CI: 53.5-68.3), respectively. The 5- and 10-years disease-specific survival was 89.9% (95% CI: 87-92.8) and 61.9% (95% CI: 56.5-67.3), respectively. Five patients (21.7%) had metastasis in regional lymph nodes.CONCLUSION:The classic type of ES represents a group of high-grade sarcomas, which affect the dominantly distal upper extremity. Specific clinical, diagnostic, and oncological characteristics make it difficult to diagnose and therapy. Wide tumor resection as a part of multimodal therapy remains a more viable and common treatment option for patients with ES on distal extremities. High rates of lymph node metastasis are typical for ES.

IntroductionMegaendoprosthesis offer a viable treatment in complex revision arthroplasty cases with good functional outcome. In the context of a neoplastic indication, the diagnosis-related group (DRG) I95A is usually assigned with a relative weight of 4.906 (2021). In contrast, in revision arthroplasty, the appropriate DRG is assigned, depending on the joint replacement. The additional costs compared to the invoiced DRG are to be compensated by agreeing on hospital-specific individual fees. These complex revision arthroplasties set high technical and operative demands and are mainly performed in specialised departments. We conducted a cost-benefit analysis of the use of the megaendoprosthesis in revision cases in a specialised orthopaedic clinic, as a single centre study. The question we sought to answer was: Is cost recovery possible in the modified German DRG system (aG-DRG)?Materials and MethodsA retrospective single centre analysis of treatment costs was performed. From 2018 to 2020, 113 patients treated with a megaendoprosthesis reconstruction in a referral centre due to extensive bone loss after aseptic or septic revision of a hip or knee prosthesis were included in the study. Relevant case-related cost drivers of the aG-DRG matrix (including staff and material costs of the operating theatre area and the ward) were taken into account. The actual costs were determined according to the specifications of the calculation manual published by the German institute for the remuneration system in hospitals (InEK). For each case, the contribution margin was calculated by relating the hospital's internal costs to the corresponding cost pool of the aG-DRG matrix.ResultsAccording to the DRG system 2021, 17 different DRGs were used for billing - in 70% based on a patient clinical complexity level (PCCL) >= 4. Compared with the InEK calculation, there is a deficit of -2,901 (sic) per case in the examined parameters. The costs of physicians show a shortfall in both the operating theatre and on the ward. Implant costs, which were supposed to be compensated by hospital-specific additional charges, show a hospital-specific shortage of -2,181 (sic). When analysing the risk factors for cost recovery, only these showed a significant difference.ConclusionImplantation of the megaendoprosthesis in revision arthroplasty is often the last option to preserve limb function. At present, despite a high degree of specialisation and process optimisation, this treatment cannot be provided cost-effectively even in tertiary care. The politically desired specialised department structure requires sufficient reimbursement for complex cases. The economic outcome of each treatment case is often unpredictable, however the surgeon is confronted with these cases and is expected to treat them. The high standard deviation indicates large differences in the cost/revenue situation of each individual case. Our results show for the first time a realistic cost analysis for megaprosthesis in revision arthroplasty and underline the importance of an adequate hospital-specific charge, individually agreed by the funding units. The calculation should include not only the implant costs, but also the increased staff costs (increased, complex planning effort, quality management, surgery time, etc.).

11531 Background: In patients with Ewing Sarcoma (EWS), adjuvant radiotherapy is often performed after surgery that could not obtain wide margins or after poor histological response to surgery. However, the benefit of adjuvant radiotherapy needs further investigation. Therefore, we compared event-free survival (EFS) between surgery (SX) alone and SX combined with radiation therapy (RT), performed a subgroup analysis and identified independent prognostic factors. Methods: The data from localized EWS patients with tumors at the extremities that were treated in the Ewing 2008 trial from 2009-2018 were included in this analysis. Patients received induction chemotherapy according to the protocol and then underwent local therapy. Patients receiving SX or adjuvant RT (combined SX/RT) were included in this analysis. Hazard ratios (HRs) (95% Confidence Intervals (CIs)) were calculated using Cox regression. Results: 360 out of 863 patients (41.7%) presented with an EWS at the extremities with 81 tumors at the upper extremity, and 279 tumors at the lower extremity. Most patients were treated with surgery only (223, 61.94%), while 125 patients (34.72%) were treated with SX plus RT. Adjuvant radiotherapy was conducted after a median time of 69 days (1st quartile, 3rd quartile; 54, 109). Median EFS at 5-years for all patients was 0.74 (0.69, 0.80), 0.76 (0.70, 0.83) for patients after surgery only, and 0.73 (0.64, 0.83) after combined RT/SX. After adjusting for sex, age, tumor volume, histological response and surgical margins, the HR for combined RT/SX vs SX alone was 0.69 (0.37, 1.26), p = 0.22. In patients with poor histological response to surgery (≥10% vital tumor cells) and with high tumor volume (≥ 200mL), additional radiotherapy did not decrease the hazards of any event, HR 0.72 (0.25, 2.06), p = 0.54. We identified high tumor volume, poor histological response to surgery as well as intralesional resection of the tumor as independent prognostic factors after adjusting for other known prognostic factors with HRs of 1.73 (1.04, 2.90), p = 0.03; 2.79 (1.69, 4.62), p < 0.0001 and 215.9 (13.17, 3538.61), p = 0.0002, respectively. Surgical complication was not a prognostic factor after adjusting for above mentioned variables, HR 0.85 (0.31, 2.34), p = 0.75. Conclusions: In our cohort, adjuvant radiotherapy was not superior compared to surgery alone in all patients with localized EWS at the extremities and neither in a subgroup of patients with high-risk factors. Poor histological response, intralesional tumor resection as well as high tumor volume were identified as independent negative prognostic factors. Clinical trial information: NCT00987636.