Level of evidence (LOE) determination is a reliable tool to assess the strength of research based on study design. Improvements in LOE are necessary for the advancement of evidence-based clinical care. The objectives of this study were to determine if the LOE presented at the Musculoskeletal Tumour Society (MSTS) annual meeting has improved over time and to determine how the LOE presented at MSTS annual meetings compares to that of the Orthopaedic Trauma Association (OTA) annual meetings. We reviewed abstracts from the MSTS and OTA annual meeting podium presentations from 2005 to 2014. Three independent reviewers evaluated a total of 1222 abstracts for study type and LOE. Changes in the distributions of study type and LOE over time were evaluated by Pearson Chi-Squared test. There were a total of 577 podium abstracts from the MSTS and 645 from the OTA. Of the MSTS therapeutic studies, 0.5% (2/376) were level I, while 75% (281/376) were level IV. There was a seven-fold higher proportion of level I studies (3.4% [14/409]) and less than half as many level IV studies (32% [130/409]) presented at OTA. There was no improvement in the MSTS LOE for all study types (p=0.13) and therapeutic study types (p=0.36) over the study decade. In contrast, the OTA LOE increased significantly over this time period for all study types (p<0.01). The proportion of controlled therapeutic studies (LOE I through III) versus uncontrolled studies (LOE IV) increased significantly over time at the OTA (p<0.021), but not at the MSTS (p=0.10). Uncontrolled case series continue to dominate the MSTS scientific program, whereas over the past decade, higher-level studies and more modern study methodology has been employed by members of the OTA

Functional outcomes are commonly reported in studies of musculoskeletal oncology patients undergoing limb salvage surgery; however, interpretation requires knowledge of the smallest amount of improvement that is important to patients – the minimally important difference (MID). We established the MIDs for the Musculoskeletal Tumor Society Rating Scale (MSTS) and Toronto Extremity Salvage Score (TESS) in patients with bone tumors undergoing lower limb salvage surgery. This study was a secondary analysis of the recently completed PARITY (Prophylactic Antibiotic Regimens in Tumor Surgery) study. This data was used to calculate: (1) the anchor-based MIDs using an overall function scale and a receiver operating curve analysis, and (2) the distribution-based MIDs based on one-half of the standard deviation of the change scores from baseline to 12-month follow-up, for both the MSTS and TESS. There were 591 patients available for analysis. The Pearson correlation coefficients for the association between changes in MSTS and TESS scores and changes in the external anchor scores were 0.71 and 0.57, indicating “high” and “moderate” correlation. Anchor-based MIDs were 12 points and 11 points for the MSTS and TESS, respectively. Distribution-based calculations yielded MIDs of 16-17 points for the MSTS and 14 points for the TESS. The current study proposes MID scores for both the MSTS and TESS outcome measures based on 591 patients with bone tumors undergoing lower extremity endoprosthetic reconstruction. These thresholds will optimize interpretation of the magnitude of treatment effects, which will enable shared decision-making with patients in trading off desirable and undesirable outcomes of alternative management strategies. We recommend anchor-based MIDs as they are grounded in changes in functional status that are meaningful to patients

Traditional staging systems for high grade osteosarcoma (Enneking, MSTS) are based largely on gross surgical margins and were developed before the widespread use of neoadjuvant chemotherapy. It is now well known that both microscopic margins and chemotherapy are predictors of local recurrence. However, neither of these variables are used in the traditional surgical staging and the precise safe margin distance is debated. Recently, a novel staging system utilizing a 2mm margin cutoff and incorporating precent necrosis was proposed and demonstrated improved prognostic value for local recurrence free survival (LRFS) when compared to the MSTS staging system. This staging system has not been validated beyond the original patient cohort. We propose to analyze this staging system in a cohort of patients with high-grade osteosarcoma, as well as evaluate the ability of additional variables to predict the risk of local recurrence and overall survival. A retrospective review of a prospectively collected database of all sarcoma patients between 1985 and 2020 at a tertiary sarcoma care center was performed. All patients with high-grade osteosarcoma receiving neo-adjuvant chemotherapy and with no evidence of metastatic disease on presentation were isolated and analyzed. A minimum of two year follow up was used for surviving patients. A total of 225 patients were identified meeting these criteria. Univariate analysis was performed to evaluate variable that were associated with LRFS. Multivariate analysis is used to further analyze factors associated with LRFS on univariate analysis. There were 20 patients (8.9%) who had locally recurrent disease. Five-year LRFS was significantly different for patients with surgical margins 2mm or less (77.6% v. 93.3%; p=0.006) and those with a central tumor location (67.9 v. 94.4; <0.001). A four-tiered staging system using 2mm surgical margins and a percent necrosis of 90% of greater was also a significant predictor of 5-year LRFS (p=0.019) in this cohort. Notably, percent necrosis in isolation was not a predictor of LRFS in this cohort (p=0.875). Tumor size, gender, and type of surgery (amputation v. limb salvage) were also analyzed and not associated with LRFS. The MSTS surgical margin staging system did not significantly stratify groups (0.066). A 2mm surgical margin cutoff was predictive of 5-year LRFS in this cohort of patients with localized high-grade osteosarcoma and a combination of a 2mm margin and percent necrosis outperformed the prognostic value of the traditional MSTS staging system. Utilization of this system may improve the ability of surgeons to stage thier patients. Additional variables may increase the value of this system and further validation is required

Functional outcomes are important for patients with bone tumors undergoing lower extremity endoprosthetic reconstruction; however, there is limited empirical evidence evaluating function longitudinally. The objective of this study was to determine the changes in function over time in patients undergoing endoprosthetic reconstructions of the proximal femur, distal femur and proximal tibia. We conducted a secondary analysis of functional outcome data from the Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY) trial. Patient function was assessed with the Musculoskeletal Tumor Society Score 93 (MSTS) and the Toronto Extremity Salvage Score (TESS), which were administered preoperatively and at 3, 6 and 12 months postoperatively. Both instruments are scored from 0-100, with higher scores indicated greater function. Mean functional scores were evaluated over time and we explored for differences among patients undergoing proximal femur reconstructions (PFR), distal femur reconstructions (DFR) and proximal tibia reconstructions (PTR). The patient-importance of statistically significant differences in function was evaluated utilizing the minimally important difference (MID) of 12 for the MSTS and 11 for the TESS. We explored for differences in change scores between each time interval with paired t-tests. Differences based on endoprosthetic reconstruction undertaken were evaluated by analysis of variance and post-hoc comparisons using the Tukey test. A total of 573 patients were included. The overall mean MSTS and TESS scores were 77.1(SD±21) and 80.2(SD±20) respectively at 1-year post-surgery, demonstrating approximately a 20-point improvement from baseline for both instruments. When evaluating change scores over time by type of reconstruction, PFR patients experienced significant functional improvement during the 3-6 and 6-12 month follow-up intervals, DFR patients demonstrated significant improvements in function at each follow-up interval, and PTR patients reported a significant decrease in function from baseline to 3 months, and subsequent improvements during the 3-6 and 6-12 month intervals. On average, patients undergoing endoprosthetic reconstruction of the lower extremity experience important improvements in function from baseline within the first year. Patterns of functional recovery varied significantly based on type of reconstruction performed. The results of this study will inform both clinicians and patients about the expected rehabilitation course and functional outcomes following endoprosthetic reconstruction of the lower extremity

Abstract. Background. Reconstruction following resection of sarcomas of the upper extremity with methods described in the prevalent literature may not be possible in few selected cases. We describe Surgical Phocomelia or Phoco-reduction as a method of limb salvage in such cases of extensive sarcomas of the upper limb with its functional and oncological outcomes. Methods. Evaluation of functional and oncological outcomes was performed for 11 patients who underwent surgical phocomelia or phocoreduction for extensive sarcomas of the upper limb between 2010 and 2019. Results. Mean follow-up period in the study was27.8 months. Five patients required a segmental resection including the entire humerus while 6 patients underwent segmental resection around the elbow with a mean resection length of 21.5 cm. Mean MSTS 93 score was 22 depicting a good functional outcome. Mean hand grip strength on the operated side was 62% of the contralateral side with preservation of useful hand function. Mean time to humero-ulnar union was 6.7 months. Radial nerve palsy and implant failure occurred in 1 patient each. No patient developed local recurrence while 3 patients died of metastasis. Conclusion. Surgical phocomelia is a prudent alternative to severely incapacitating amputations in situations where other reconstruction methods are not feasible

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

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

Objective. was to review the experience of the Rizzoli with megaprosthetic reconstruction of the extremities in musculoskeletal oncology. Material and methods. Between April 1983 and December 2007, 1036 modular uncemented megaprostheses of the lower limbs were implanted in 605 males and 431 females: 160 KMFTR(r), 633 HMRS(r) prostheses, 68 HMRS(r) Rotating Hinge and 175 GMRS(r). Sites: distal femur 659, proximal tibia 198, proximal femur 145, total femur 25, distal femur and proximal tibia 9. Histology showed 612 osteosarcomas, 113 chondrosarcomas, 72 Ewing's sarcoma, 31 metastatic carcinomas, 89 GCT, 36 MFH,68 other diagnoses. Between 1975 and 2006 at Rizzoli 344 reconstructions of the humerus using prosthetic devices (alone or in association with allografts) were performed: 289 MRS(r), 37 HMRS(r), 2 Osteobridge(r), 4 composite prostheses, 8 Coonrad-Morrey(r), 4 custom made prostheses. Sites of reconstruction were: proximal humerus 311, distal humerus 19, diaphysis 5, total humerus 9. Histology showed 146 osteosarcomas, 56 chondrosarcomas, 23 Ewing's sarcoma, 67 metastatic carcinomas, 14 GCT, 10 MFH, 28 other diagnoses. Patients were followed periodically in the clinic. Information were obtained from clinical charts and imaging studies with special attention to major complications requiring revision surgery. Major prostheses-related complications were analysed and functional results evaluated according to the MSTS system. Univariate analysis by Kaplan-Meier actuarial curves was used for studying implant survival to major complications. Results. Major complications causing implants failure in lower limbs were 80 infections (7.7%), 64 aseptic loosening (6.2%) and 33 breakages (3.2%). In lower limbs infection occurred in 18 KMFTR(r), 47 HMRS(r), 5 HMRS(r) Rotating Hinge, 10 GMRS(r). Breakage of the prosthetic reconstruction occurred in 16 KMFTR(r), 16 HMRS(r), 1 HMRS(r) Rotating Hinge. Aseptic loosening occurred in 15 KMFTR(r), 28 HMRS(r), 18 HMRS(r) Rotating Hinge, 3 GMRS(r). Major complications causing implants failure in upper limbs were 15 infections (4.3%), 8 aseptic loosening (2.3%) and 4 breakages (1.2%). In upper limbs infection occurred in 14 MRS(r) and 1 Coonrad-Morrey(r). Aseptic loosening in 8 cases MRS(r). Breakage in 4 cases MRS(r) prostheses. Most patients in both lower and upper extremities series showed satisfactory function (good or excellent) according to the MSTS evaluation system. Implant survival to all major complications of lower limb megaprostheses evaluated with Kaplan-Meier curve was 80% at 10 years and 60% at 20 years. Implant survival for the newer designs (GMRS(r)) available only at middle term follow up showed an implant survival to major complications at about 90% at 5 years. Implant survival to all major complications was over 80% at 10 years and 78% at 20 years. Conclusions. Megaprostheses are the most frequently used type of reconstruction after resection of the extremities, since they provide good function and a relatively low incidence of major complications. Both function and implant survival improved in the last decades with the introduction of newer designs and materials

Navigation-assisted surgery has been reported to enhance resection accuracy in bone sarcoma surgery. Patient-specific instruments (PSIs) have been proposed as a simpler alternative with fewer setup facilities. We investigated the use of 3D surgical planning and PSI in realising computer planning of complex resections in bone sarcoma patients with regards to surgical accuracy, problems, and early clinical results. We retrospectively studied twelve patients with bone sarcoma treated surgically by PSIs with 3D planning. The procedure was planned using engineering software. The resection accuracy was accessed by comparing CT images of tumour specimens with the planned in seven patients. Mean age was 30.9 (9 – 64). Mean follow-up was 3.1 year (0.5 – 5.3). 31 planes of bone resections were successfully performed using the technique and were considered accurate. The mean time required for placing PSIs was 5.7 minutes (1 – 10) and performing bone osteotomies with the assistance of PSIs was 4.7 minutes (2 – 7). The mean maximum deviation error was 1.7mm (0.5 – 4.4). One PSI was broken during bone resection, and one patient needed re-resection using the same PSI. One pelvic patient died of local recurrence and lung metastases six months postoperatively. One patient developed a soft tissue local recurrence and lung metastasis at 20 months after surgery. The mean MSTS functional score was 27.9 (21 – 30). There were no complications related to 3D planning and PSIs. In selected patients, 3D surgical planning and PSIs replicate complex bone resections and reconstructions in bone sarcoma surgery. Comparative studies with conventional or navigation- assisted resections are required

Introduction and Purposes. Custom made acetabular prosthesis are a valid option for the reconstruction after the resection of pelvic tumors. They should guarantee a stable and reliable reconstruction for the expected survival of the patient. Nevertheless in many cases periacetabular metastatic lesions have been compared to high grade (IIIA-B) Paprosky defects, but treated with low or intermediate longevity implants. Some complex post-traumatic scenarios or total hip arthroplasty (THA) multiple failures need a reconstruction according to oncologic criteria to fill in the huge defect and to obtain an acceptable function. The aim of the study is to compare 3D custom-made implants for tumors and for THA failures. Materials and Methods. Three custom-made implants after tumor resection (group A: 1 chondroblastic osteosarcoma, 1 bifasic synovialsarcoma, 1 high grade chondrosarcoma) were evaluated and compared to 3 acetabular complex reconstructions after non-oncologic bone defect (group B: 3 cases of aseptic loosening after at least 2 revisions). All the implants were case-based designed, 3D printed, and realized with porous or trabecular surfaces on a Titanium base prosthesis. Age range 16–70 ys in oncologic patients and 60–75 ys in non-oncologic patients. The bone defect to be reconstructed after tumor resection was classified according to Enneking zones (1 type 1-2-3 resection, 1 type 2 resection, 1 partial type 2 resection). Non-oncologic cases were comparable in term of remaining bone stock and classified according to Paprosky classification for acetabular defects as 1 type IIIA an 2 type IIIB. Complications, MSTS functional score, necessity of walking-aids were evaluated at minimum follow up of 1 year. Results. In both groups, good functional results were obtained (MSTS score 25/30 in both groups). No cases of aseptic loosening and no infection occured. After 3 months of partial or no weight-bearing on the operated limb, 3 patients were able to walk unaided and 3 walked with one cane or crutch. No limb length discrepancy (major than 2 cm) were observed. Limping was present in oncologic cases due to muscle resection. Overall better results in term of satisfaction and quality of life were obtained in younger (oncologic) patients. Conclusions. Complex THA revision cases can sometimes be considered for a reconstruction with oncologic criteria. Even if indications are limited an acceptable functional results can be obtained. In the past for these cases a Girldestone resection was the only option. A collaboration among orthopaedic oncologist and hip arthroplasty surgeons is advisable in major orthopaedic centers to improve the prosthetic design and the functional results

Hypothesis. Cartilage defects pretreated with marrow stimulation techniques will have an increased failure rate. The first 321 consecutive patients treated at one institution with autologous chondrocyte implantation for full-thickness cartilage defects that reached more than two years of follow-up were evaluated by prospectively collected data. Patients were grouped based on whether they had undergone prior treatment with a marrow stimulation technique. Outcomes were classified as complete failure if more than 25% of a grafted defect area had to be removed in later procedures because of persistent symptoms. Results. There were 522 defects in 321 patients (325 joints) treated with autologous chondrocyte implantation. On average, there were 1.7 lesions per patient. Of these joints, 111 had previously undergone surgery that penetrated the subchondral bone; 214 joints had no prior treatment that affected the subchondral bone and served as controls. Within the marrow stimulation group, there were 29 (26%) failures, compared with 17 (8%) failures in the control group. Conclusion. Defects that had prior treatment affecting the subchondral bone failed at a rate three times that of nontreated defects. The failure rates for drilling (28%), abrasion arthroplasty (27%), and microfracture (20%) were not significantly different—possibly because of the lower number of microfracture patients in this cohort (25 of 110 marrow-stimulation procedures). The data demonstrate that marrow stimulation techniques have a strong negative effect on subsequent cartilage repair with autologous chondrocyte implantation and, therefore, should be used judiciously in larger cartilage defects that could require future treatment with autologous chondrocyte implantation. Unlike coventional wisdom, MSTs do ‘burn bridges’

Objectives. A defect following resection of Giant Cell Tumour of the distal radius (GCT-DR) is reconstructed by either vascularised free fibular transfer (VFF) or non-vascularised structural iliac crest transfer (NIC). The purpose of this study was to compare these procedures. Methods. Twenty-seven patients at two centres were identified, 14 underwent VFF and 13 NIC. The two groups were comparable for age, sex, and tumour grade. Functional outcomes were assessed with TESS, MSTS, and DASH. In the VFF group, ankle joint morbidity was assessed with the Ankle Osteoarthritis Scale. In the NIC group, iliac crest morbidity was assessed with a short questionnaire. Results. Two local recurrences occurred in the VFF group and one in the NIC group. Following the index surgery, three patients in the VFF group underwent surgery for cosmesis, hardware removal or tendon release, and one is scheduled for tendon release. In the NIC group two infections required debridement, one of which went on to free fibular transfer, but there were no re-operations for union or donor site morbidity. The surgical time was significantly shorter for NIC. Functional scores showed no differences between the groups on any of the parameters studied for the upper limb (Mann-Whitney test). The Anke OA scale and the iliac crest morbidity questionnaire revealed only a few mild problems with donor site morbidity in either group. Conclusion. Both VFF and NIC are effective surgical techniques that result in a well-functioning wrist arthrodesis. VFF should be considered when there is a significant skin defect, as it allows the inclusion of a vascularised skin paddle, or when the osseous defect is too long for NIC. We were unable to demonstrate any difference in functional scores between VFF and NIC. As the re-operation rate is less for NIC and surgical time is shorter, we recommend NIC whenever possible

Purpose. of this study is to analyze the results of a modular reconstructive tumor prosthesis for the lower limb (GMRS. (r). ) with a comparative statistical analysis of primary and secondary implants. Material and methods. From October 2003 to September 2007 at Rizzoli 161 GMRS. (r). prostheses were implanted, most after resection of osteosarcoma (94 cases, 58%). It is a modular system with a rotating hinge mechanism for the knee, cemented and uncemented stems, in titanium and chromium-cobalt-molybdenum, curved and straight-fluted, with or without hydroxyapatite coating. Moreover adaptors are available to revise HMRS. (r). implants. This series includes 88 males and 73 females ranging in age from 9 to 80 years. Sites of reconstruction were 109 distal femurs, 19 proximal femurs, 1 total femur and 32 proximal tibias. There were 149 oncologic and 12 non oncologic diagnoses, including 96 primary reconstructions and 65 revisions after failure of previous implant. A retrospective analysis of imaging and complications was performed and functional results assessed according to MSTS system. Statistical analysis with Kaplan-Meier curves was used to study implant survival. Results. At a mean follow up of 2 yrs. 106 patients are continuously NED, 31 are NED after treatment of one or more local recurrence or metastasis, 7 AWD, 5 DWD. There were 10 major complications: 8 infections (4,7%) (5 in primary and 3 in secondary implants, 2 previously infected) and 2 aseptic loosening (1,2%) (1 each). There were 9 minor complications (4 wound sloughs, 1 stiff joint, 3 disrupted extensor apparatus,1 patellar instability) requiring revision. Comparative statistical analysis of primary and secondary implants survival at major complications shows no statistically significant difference. Functional results were good or excellent in 95% of the evaluated patients, without any poor. Conclusions. Middle term results are promising: good function, very low incidence of major complications, no breakage of implant components. This prosthetic reconstruction is indicated in oncological cases as well as in selected in some non oncological settings, such as challenging revisions of prosthetic failures with massive bone loss or post-radiation non unions or allografts failures. Although a higher incidence of complications was expected in secondary implants, statistical analysis shows similar survival

Objective. of this study was to analyse results of two stage revisions in infected megaprostheses in lower limb. Material and methods. Between April 1983 and December 2007, 1036 modular uncemented megaprostheses were implanted in 605 males and 431 females with mean age 33.5 yrs: 160 KMFTR. (r). , 633 HMRS. (r). prostheses, 68 HMRS. (r). Rotating Hinge and 175 GMRS. (r). Sites: distal femur 659, proximal tibia 198, proximal femur 145, total femur 25, distal femur and proximal tibia 9. Histology showed 612 osteosarcomas, 113 chondrosarcomas, 72 Ewing's sarcoma, 31 metastatic carcinomas, 89 GCT, 36 MFH,68 other diagnoses. Infection occurred in 80 cases (7.7%) at mean time of 4 yrs (min 1 month, max 19 yrs) in 18 KMFTR. (r). , 47 HMRS. (r). , 5 HMRS. (r). Rotating Hinge, 10 GMRS. (r). Sites: 51 distal femurs, 21 proximal tibias, 6 proximal femurs, 1 total femur and 1 extrarticular knee resection. Most frequent bacteria causing infection were: Staphilococcus Epidermidis (39 cases), Staphilococcus Aureus (17) and Pseudomonas Aeruginosa (5). Infection occurred postoperatively within 4 weeks in 9 cases, early (within 6 months) in 12 cases, late (after 6 months) in 59 cases. Usual surgical treatment was “two stage” (removal of implant, one or more cement spacers with antibiotics, new implant), with antibiotics according with coltures. One stage treatment was used for immediate postoperative infections, only since 1998. Functional results after treatment of infection were assessed using the MSTS system. Results. A two stage revision was attempted in 73 pts (91.2%): in 58 cases a new prostheses was implanted (with negative laboratory tests for infection) at mean time of 5 months (min 2, max 16 months), but in 3 pts infection recurred and they were amputated; 4 pts died before implanting a new prosthesis; 11 pts were amputated after several spacers since infection did not heal. One stage revision was performed in 4 of the 9 immediate postoperative infections, with successful results. In 3 cases an amputation was primarily performed, to proceed with chemotherapy. Revisions for infection were successful in 63 pts (79%), while 17 pts were amputated (21%). Functional results evaluated in 53 revised cases were good or excellent in 43 (81.1%). Conclusions. Two stage treatment of infected megaprostheses is successful in most cases. One stage has selected indications, mainly in postoperative immediate infections