MRI radiomics-based machine learning for classification of deep-seated lipoma and atypical lipomatous tumor of the extremities.

PURPOSE: To determine diagnostic performance of MRI radiomics-based machine learning for classification of deep-seated lipoma and atypical lipomatous tumor (ALT) of the extremities. MATERIAL AND METHODS: This retrospective study was performed at three tertiary sarcoma centers and included 150 patients with surgically treated and histology-proven lesions. The training-validation cohort consisted of 114 patients from centers 1 and 2 (n = 64 lipoma, n = 50 ALT). The external test cohort consisted of 36 patients from center 3 (n = 24 lipoma, n = 12 ALT). 3D segmentation was manually performed on T1- and T2-weighted MRI. After extraction and selection of radiomic features, three machine learning classifiers were trained and validated using nested fivefold cross-validation. The best-performing classifier according to previous analysis was evaluated and compared to an experienced musculoskeletal radiologist in the external test cohort. RESULTS: Eight features passed feature selection and were incorporated into the machine learning models. After training and validation (74% ROC-AUC), the best-performing classifier (Random Forest) showed 92% sensitivity and 33% specificity in the external test cohort with no statistical difference compared to the radiologist (p = 0.474). CONCLUSION: MRI radiomics-based machine learning may classify deep-seated lipoma and ALT of the extremities with high sensitivity and negative predictive value, thus potentially serving as a non-invasive screening tool to reduce unnecessary referral to tertiary tumor centers.

CT-guided radiofrequency ablation of painful intra-articular osteoid osteoma in children: Is there a concern for cartilage damage?

OBJECTIVE: To evaluate the safety and efficacy of computed tomography-guided percutaneous radiofrequency ablation (PRFA) in the management of uncommon and technically challenging intra-articular osteoid osteoma in children. MATERIAL AND METHODS: From December 2018 to September 2022, 16 children with intra-articular osteoid osteoma, including ten boys and six girls, were treated at two tertiary centers with percutaneous CT-guided RF ablation using a straight monopolar electrode. The procedures were carried out under general anesthesia. Post-procedural clinical outcomes and adverse events were assessed through clinical follow-up. RESULTS: Technical success was achieved in all of the participating patients. Clinical success with relief of symptomatology throughout the period of follow-up was achieved in 100% of the patients. No persistence or recurrence of pain occurred during the follow-up period. No immediate or delayed adverse effects were observed. CONCLUSION: PRFA is shown to be technically feasible. Clinical improvement can be achieved with a high rate of success in the treatment of children with difficult-to-treat intra-articular osteoid osteomas.

Role of percutaneous CT-guided radiofrequency ablation in treatment of intra-articular, in close contact with cartilage and extra-articular osteoid osteomas: comparative analysis and new classification system.

PURPOSE: We investigated procedural safety, technical and clinical outcomes of the percutaneous image-guided radiofrequency ablation (PRFA) of intra-articular (IA), intra-articular close to cartilage (IACC), and extra-articular (EA) osteoid osteomas (OO). We proposed a new radiologic classification for osteoid osteoma depending on the degree and location of sclerosis which may correlate with technical failure and/or difficulties. MATERIAL AND METHODS: According to the inclusion criteria, we enrolled consecutive patients who were referred to the investigation center from June 2018 to January 2022. After clinical and CT imaging features were suggestive for the diagnosis of OO, all the patients were treated by percutaneous CT-guided RFA with a standardized technique. Biopsy of the lesion was not performed in all patients. A retrospective analysis was conducted to assess the procedure's technical, primary clinical, and secondary clinical successes, recurrence rate, and complications. We classified all the OOs according to a new proposed classification of the site and the amount of sclerosis. RESULTS: A total number of 55 patients were enrolled in our study according to the inclusion criteria. The mean age of the enrolled patients was 24.07 ± 14.71 years (ranges from 7 to 57 years). The M/F ratio was roughly 2:1. The mean follow-up was 20.18 ± 12.60 months (ranges from 2 to 44 months). EA group included 36 patients, IA included 5 and IACC included 14 patients. Technical success was achieved in all cases of IA and IACC groups. Technical success in the EA group was 97.22% (1 technical failure). Primary clinical success was 100%, 92.85%, and 91.66% for IA, IACC, and EA groups, respectively. Accordingly, the recurrence rate was 5.88% in EA, and 7.14% in IACC, while no recurrence occurred in the IA group. No complications occurred. The secondary success rate of the 3 cases of recurrence was 100%. CONCLUSIONS: PRFA proved to be a safe procedure with a high rate of success for OO treatment even in intra-articular lesions in close contact with cartilage. This study showed that the results in terms of technical and clinical success are comparable for IA OO, IACC OO, and EA OO, even if the recurrence rate was higher in EA OO. Our proposed new classification of the degree and location of sclerosis may correlate to technical failure, but further studies with a larger number of patients are needed for validation.

Atypical diaphyseal femoral fractures: Considerations on surgical technique.

In the last two decades bisphosphonates (BP) has become the mainstream therapy for osteoporosis and the benefit in reducing the incidence of fractures has been well demonstrated in several studies, together with the drug long term (5-10 years) efficacy and safety. A complication of the long-term use of bisphosphonates is a low-energy stress fractures located in the sub-trochanteric region and the femoral shaft called atypical femur fracture (AFF). These stress fractures can be seen on plain radiographs as simple transverse patterns, with unicortical beaking and hypertrophy of the diaphyseal lateral cortex. Usually a localized thigh pain in the prodromal phase may precede the fracture by months. The current surgical treatment of choice for AFFs is intramedullary nailing (IMN). However, the treatment of AFFs is associated with a higher rate of intra-operative and post-surgical complications. This is related to anatomical e biomechanical reasons. Iatrogenic fractures, deformities, medial gap opening, eccentric position of the distal nail tip with anterior cortex perforation, delayed or non-union are frequent complications of this procedure and healing rate of AFFs. The average healing time of almost 8 months for AFFs appeared to be longer than that for typical femoral fractures, which heal at an average of 3-6 months. The purpose of this study is to analyze the different surgical devices and techniques and to advance some considerations that can be useful to diminish the rate of failure and/or complications in the treatment of AFFs in both oncologic and osteoporotic patients.

Carbon-fiber reinforced intramedullary nailing in musculoskeletal tumor surgery: a national multicentric experience of the Italian Orthopaedic Society (SIOT) Bone Metastasis Study Group.

INTRODUCTION: Carbon fiber reinforced (CFR) implants have been proposed for the treatment of fractures or impending fractures of the long bones in the oncology patient. Aim of this study is to present the largest cohort of oncology patients operated by CFR nailing by the Italian Orthopaedic Society (SIOT) Bone Metastasis Study Group. METHODS: 53 adult oncology patients were operated on with a CFR-PEEK nail. All the data from adjuvants therapies were collected. Bone callus formation, response to radiotherapy, relapse or progression of the osteolysis were recorded. Hardware survival and failure, breakage and need for implant revision were also analysed. RESULTS: Anatomical implantation of nails include humerus (n = 35), femur (n =11) and tibia (n = 7). The most frequent tumors affecting the bone were myeloma (n = 13), breast (n = 11), lung (n = 8), and renal cell cancer (n = 7). Acrylic cement reinforcement was used in 2 patients. One patient was subjected to electrochemotherapy after nail insertion. Intraoperative and early postoperative complications occurred in 13.2% and 7.54% of patients respectively. Eight patients had local progression and one developed a stress fracture proximally to the distal static screw. Radiographic union occurred in 14 patients; one screw loosening was recorded. DISCUSSION: There is currently a lack of solid evidence on the clinical use of CFR nails in oncologic patients. This is the first and largest study of CFR nailing, with the longest available follow up. CONCLUSIONS: Implant related complications and surgery-related morbidity should be taken into account in the decision-making process for the surgical management of these patients. These data can improve the surgeon-patient communication and guide further studies on patients' survival and complications with respect to surgery.

Catastrophic metallosis after tumoral knee prosthesis failure: A case report.

INTRODUCTION: Metallosis is a condition characterized by an infiltration of periprosthetic soft tissues and bone by metallic debris resulting from wear or failure of joint arthroplasties. PRESENTATION OF CASE: Authors describe a case of a 45-year-old man treated for an osteosarcoma of the distal femur with a modular prosthesis when he was 18 years old, he developed massive metallosis with skin dyspigmentation after 17 years. His medical\surgical history was remarkable for a left tumoral knee prosthesis implanted 21 years ago. Two years before revision, the patient had a car accident with a two-points prosthesis breakage and despite the surgeon's advice, the patient refused surgery. In two years, prosthesis malfunction caused a progressive catastrophic soft tissues infiltration of metallic debris. DISCUSSION AND CONCLUSION: Authors suggest that if prosthesis fracture is detected, revision surgery should be attempted as earlier as possible.

Infective complications in tumour endoprostheses implanted after pathological fracture of the limbs.

INTRODUCTION: Pathological fractures represent an adverse prognostic factor in primary and metastatic bone tumours. The purpose of this study was to evaluate the results of tumour silver-coated prosthesis implanted after pathological fractures. MATERIALS AND METHODS: A retrospective analysis was conducted on 30 patients with pathological limb fracture after primary or metastatic bone tumours treated by the same surgeon with wide margin resection and tumour prosthesis implant between 2005 and 2015. Silver-coated prostheses were implanted in 17 patients and uncoated prostheses were implanted in 13 patients. The primary outcome of the study was to evaluate the infective risk, the secondary outcomes were survival and functional level (visual analogue scale [VAS], 36-Item Short Form Health Survey [SF 36], and Musculoskeletal Tumour Society [MSTS] score) obtained at the longest follow-up available. A multivariate analysis was performed considering age, sex, tumour histology, grading and location, resection size, concomitant radiotherapy/chemotherapy, use of mesh for soft tissue reconstruction and local complications (dislocation, relapse, implant breakage). Scanning electron microscopy (SEM) analysis of explanted prosthesis was performed to study the residual silver-coating. RESULTS: The average age of patients in the study was 56.2 years (range 12-78 years). Silver-coated prostheses were implanted in 56.7% of patients, and uncoated tumour prostheses were used in the remaining 43.3%. The mean follow-up was 40.7 months. A total of 26.7% of patients died at a median time of 28.6 months after surgery. The overall rate of complications was 30%, with 16.7% due to infection. A total of 11.8% of the patients treated with silver-coated implants developed infection compared with 23.1% of the patients treated with uncoated tumour prostheses. There were no cases of early infection in the silver-coated prosthesis group, whereas early infection occurred in 66.7% of patients in the uncoated prosthesis group. All the functional outcomes were significantly improved after surgery. None of the other parameters analysed can be considered a significant negative prognostic factor for infection. The SEM analyses showed severe silver-coating degradation 2 years after first implant. No case of silver toxicity was demonstrated. DISCUSSION: There are few papers in the literature about infective complications in tumour prosthesis after pathological fracture. Silver-coated implants showed a protective action against early infection. Late infection rate was similar between the groups, thereby indicating a reduction of antimicrobial activity for the silver-coating over time. CONCLUSIONS: Silver-coated prostheses are a protective factor against early infections in limb salvage surgery after pathological fractures, so may represent the first-choice of implants in this type of surgery.

Fractures in bone tumour prosthesis.

PURPOSE: The aim of the present narrative review is to report the different aspects related to the fractures around tumour prosthetic implants in terms of technical and medical issues. METHODS: A non systematic literature review on the topic was performed. RESULTS: Given the increased rate of limb salvage procedures and megaprostheses implanted for bone tumours, the increased number of osteoporotic periprosthetic fractures, and the burden of revision arthroplasty, the number of surgeries using endoprosthetic implants is likely to increase in the near future. Surgeons will face more frequently the complications related to tumour endoprosthetic implant. Endoprosthetic reconstruction has a higher risk of intra-operative and post-operative complications compared to conventional prosthetic replacement. CONCLUSIONS: Very rare reports and recommendations are available in literature regarding the treatment of periprosthetic fractures after megaprosthesis, and there is currently no consensus about which should be the standard management for periprosthetic fractures in this population of patients.

Bone metastases of unknown origin: epidemiology and principles of management.

UNLABELLED: Metastases are the most common malignancies involving bone; breast, prostate, lung and thyroid are the main sites of primary cancer. However, up to 30 % of patients present with bone metastases of unknown origin, where the site of the primary neoplasm cannot be identified at the time of diagnosis despite a thorough history, physical examination, appropriate laboratory testing and modern imaging technology (CT, MRI, PET). Sometimes only extensive histopathological investigations on bone specimens from biopsy can suggest the primary malignancy. At other times, a bone lesion can have such a highly undifferentiated histological appearance that a precise pathological classification on routine hematoxylin-eosin-stained section is not possible. The authors reviewed the relevant literature in an attempt to investigate the epidemiology of the histological primaries finally identified in patients with bone metastases from occult cancer, and a strategy of management and treatment of bone metastases from occult carcinomas is suggested. Lung, liver, pancreas and gastrointestinal tract are common sites for primary occult tumors. Adenocarcinoma is the main histological type, accounting for 70 % of all cases, while undifferentiated cancer accounts for 20 %. Over the past 30 years, lung cancer is the main causative occult primary for bone metastases and has a poor prognosis with an average survival of 4-8 months. Most relevant literature focuses on the need for standardized diagnostic workup, as surgery for bone lesions should be aggressive only when they are solitary and/or the occult primaries have a good prognosis; in these cases, identification of the primary tumor may be important and warrants special diagnostic efforts. However, in most cases, the primary site remains unknown, even after autopsy. Thus, orthopedic surgery has a mainly palliative role in preventing or stabilizing pathological fractures, relieving pain and facilitating the care of the patient in an attempt to provide the most appropriate therapy for the primary tumor as soon as possible. LEVEL OF EVIDENCE: 5.

Impending fracture: A difficult diagnosis.

INTRODUCTION: The concept of impending fracture has been developed to help address this difficult skeletal-related problem. There is no consensus on the subject in the literature and a specific definition of impending fracture has not been outlined. DISCUSSION: There is disagreement in the literature on the best criteria for the diagnosis of impending fracture. A method of discrimination for patients who need preventative treatment for a metastatic lesion has not yet been established. CONCLUSIONS: Current score systems consider variables like size, location and treatment response and are easy to remember. However, these score systems have never been evaluated prospectively and rigorously, their sensitivity is low and they do not take into account potentially relevant factors that can influence patient prognosis. A consistent tool to evaluate impending fractures would be of great value to guide the treatment of metastatic bone disease.

Management of long bone metastases: recommendations from the Italian Orthopaedic Society bone metastasis study group.

The purpose of this article is to outline the current approach to patients affected by metastasis to the long bones and to present a clinical and surgical algorithm available for clinicians and for future research. A modern approach to patients affected by long bone metastasis in fact requires a multidisciplinary contest where oncologists, radiotherapists, surgeons and physical therapists cooperate with a shared vision, in order to provide the best possible integrated treatments available. The authors of this article constitute the Bone Metastasis Study Group of the Italian Orthopaedic Society (SIOT): a national group of orthopedic tumor surgeons who are dedicated to studying the approach, techniques and outcomes of surgery for metastatic tumours of the musculoskeletal system.

Intramedullary nailing for treatment of pathologic femoral fractures due to metastases.

Pathologic fractures of the femur because of bone metastases seriously affect the quality of life of cancer patients. Different surgical options are indicated to achieve a durable and solid fixation, depending on several clinical, prognostic and mechanical factors. Locked intramedullary nailing is currently used to treat pathologic femoral fractures in patients with multiple metastases when the trochanteric region or shaft is mainly involved. This study evaluates intramedullary nailing for treatment of patients with pathologic femoral fractures, focussing on complications, clinical and functional outcomes and survival rates. The series included 80 pathologic fractures treated with a titanium alloy Proximal Nail (Standard or Antirotation) or Lateral Anterograde Femoral Nail (PFN, PFNA or LAFN, Synthes) inserted in a locked static mode. Acrylic cement was used to fill the bone cavity after nail insertion in eight patients; percutaneous cementoplasty was simultaneously performed in 11 cases of severe ipsilateral acetabular osteolysis. Postoperative outcomes focussed on pain relief, postoperative mobility and quality of life and they were analysed retrospectively using QOL-ACD and ECOG. Eleven patients (13.75%) suffered from non-fatal DVT post-surgery, with no pulmonary embolism. Six patients (7.5%) developed superficial wound infections and two patients (2.5%) developed pnaeumonia. There was no loss of reduction, breakage, screw pull out, or hardware or implant failure that required component substitution or revision. Lung histotype and the contemporary presence of cerebral and visceral metastases appeared to be predisposing factors in reducing survival time. All patients attained satisfactory pain relief, early deambulation and a marked clinical improvement during the first 6-10 postoperative months, with gradual worsening thereafter from deterioration of their general condition due to cancer progression. The patients' survival rate was 40% at 1 year, 25% at 2 years and 15% at 3 years. Results confirm that multiple factors related to patients and primary cancer may affect survival rate after femoral fracture. Intramedullary nailing should be indicated for pathologic fractures at femoral diaphysis and metaphysis when cancer is in an advanced stage. This procedure offers good and durable stability, and enables pain relief, early postoperative mobilisation and weight-bearing, thus improving the quality of life of cancer patients.

A case of parosteal osteosarcoma with a rare complication of myositis ossificans.

We report the case of a parosteal osteosarcoma of the distal ulna, treated with wide resection without reconstruction. The patient developed lung metastasis and a mass in the interosseus membrane of the forearm proximally to the osteotomy. The lung mass was found to be a metastasis from parosteal osteosarcoma and the biopsy of the forearm mass revealed a myositis ossificans. The suspicion of a recurrence of parosteal osteosarcoma, already metastatic, led to a second wide resection with no reconstruction. A slice of the radial cortex was taken during this second procedure. From a histological point of view, good margins were achieved and diagnosis of myositis ossificans was confirmed. Two months later, a radius fracture occurred and a synthesis, with plate and screws, as added with poly(methyl methacrylate) (PMMA) to reconstruct the bone loss, was performed. Indication of the reconstructive technique and the complication after distal ulna resection in oncologic surgery are discussed in this paper.

Synovial hemangiohamartoma presenting as knee pain, swelling and a soft tissue mass: a case report.

INTRODUCTION: We present a case of a patient with juxtaarticular hemangiohamartoma with a synovial extension associated with hemorrhagic synovitis and recurrent spontaneous hemarthrosis. CASE PRESENTATION: A 21-year-old Caucasian woman was admitted to our hospital complaining of pain and swelling at her knee for 6 months. In the magnetic resonance imaging, T2-weighted and fat-suppressed scans revealed a mass with high signal intensity just posterior to the patellar tendon. We performed an excisional biopsy of the mass through an anterior longitudinal incision. Excised material included arterial and venous vascular structures, which were found to be spread among the fat, connective and peripheral nerve tissues microscopically. CONCLUSION: Although hemangiohamartomas are not true neoplasms, they may cause knee pain, swelling and hemarthrosis that warrant surgical resection. This lesion, although rare, should be considered in the differential diagnosis, especially in teenagers and young adults.

Physiopathology of Bone Modifications in ß-Thalassemia.

ß-thalassemia major (ßTM) or Cooley anemia is characterized by significantly reduced or absent synthesis of ß-globin chains, which induces important pathologic consequences including hemolytic anemia, altered erythropoiesis, and bone marrow overstimulation. The pathogenesis of bone changes in patients with ßTM is not yet completely understood. However, an unbalance in bone mineral turnover resulting from increased resorption and suppression of osteoblast activity has been detected in ßTM patients. The abnormal regulation of bone metabolism may be related to hormonal and genetic factors, iron overload and iron chelation therapy, nutritional deficits, and decreased levels of physical activity. Here, we review the most recent findings on the physiopathology of bone abnormalities in ßTM. Clinical presentation and radiological features of ßTM-related bone changes are also discussed.

Clinical management and surgical treatment of distal fibular tumours: a case series and review of the literature.

PURPOSE: Study reports clinical and functional outcomes of surgical treatment in a case series of nine patients with distal fibular tumours. METHODS: Nine patients with distal fibular tumours were observed between 2005 and 2010. A PubMed search was performed using the terms "fibula", "lower limb tumour [cancer]", "sarcoma", "Ewing", "peroneal", "fibular metastasis", and "limb-salvage surgery". RESULTS: In all our patients, lesions were unilateral. All patients complained of pain; limping was present in 5 of 9 tumours. Patients were managed surgically, except one who underwent local radiotherapy. In six patients, a benign or tumor-like lesion was detected. Malignancies consisted of metastatic lung adenocarcinoma (two cases) or multifocal mesenchymal cancer (one case). Non-malignant lesions were treated by curettage and filling, followed by internal fixation when needed. In malignant or locally aggressive lesions, metadiaphyseal fibular resection was performed. The literature search retrieved either case reports or small case series, reflecting the rarity of distal fibular tumours. Surgical treatment was successful in all patients with benign lesions, whereas the rate of success was 40-100 % in case of malignancies. CONCLUSIONS: Given the low incidence of distal fibular tumours, controversies exist about the optimal surgical management. Clinical observation and imaging should be reserved to asymptomatic benign lesions. In non-malignant tumours causing pain, limping, and pathological fractures; in malignancies, surgery is recommended. Finally, in patients with asymptomatic lesions of uncertain nature, biopsy and histological examination should be performed to plan appropriate management.

Physiopathology of spine metastasis.

The metastasis is the spread of cancer from one part of the body to another. Two-thirds of patients with cancer will develop bone metastasis. Breast, prostate and lung cancer are responsible for more than 80% of cases of metastatic bone disease. The spine is the most common site of bone metastasis. A spinal metastasis may cause pain, instability and neurological injuries. The diffusion through Batson venous system is the principal process of spinal metastasis, but the dissemination is possible also through arterial and lymphatic system or by contiguity. Once cancer cells have invaded the bone, they produce growth factors that stimulate osteoblastic or osteolytic activity resulting in bone remodeling with release of other growth factors that lead to a vicious cycle of bone destruction and growth of local tumour.