Bone Tumors Of Femur Research Articles

Prediction of Femoral Bone Strength in the Presence of Tumors and Tumor-like Lesions Using Finite Element Analysis.

Patients with bone tumors in their femurs are at risk of developing pathological fractures. Tumors with high fracture risk, especially fragile malignant lesions, are treated surgically. However, it is difficult to estimate bone strength based on clinical and radiographic findings. This study aimed to determine whether finite element analysis (FEA) provides useful information on the bone strength of femurs with tumors and tumor-like lesions. Total femoral computed tomography (CT) data (slice thickness, 0.5 mm) were retrospectively obtained from 18 patients with femoral bone tumors. Three-dimensional FEA of femurs were developed using CT data. The virtual femoral head compression test and direct three-point bending test were performed on the femurs using FEA to predict bone strength and fracture location. The compression direction was parallel to the mechanical axis, whereas that of the three-point bending test was applied to the tumor itself. In the femoral head compression test using FEA, 13 out of 18 femurs with bone tumors fractured at the femoral head, while 14 out of 18 femurs fractured at the tumor site during the virtual direct three-point bending test. The median loads predicted using the femoral head compression test were significantly higher than those predicted by the direct three-point bending test. The FEA results indicated that pathological fractures are unlikely to occur during normal walking. Direct external forces applied to the tumor body may lead to fractures.

An enhanced AlexNet-Based model for femoral bone tumor classification and diagnosis using magnetic resonance imaging

ObjectiveBone tumors, known for their infrequent occurrence and diverse imaging characteristics, require precise differentiation into benign and malignant categories. Existing diagnostic approaches heavily depend on the laborious and variable manual delineation of tumor regions. Deep learning methods, particularly convolutional neural networks (CNNs), have emerged as a promising solution to tackle these issues. This paper introduces an enhanced deep-learning model based on AlexNet to classify femoral bone tumors accurately. MethodsThis study involved 500 femoral tumor patients from July 2020 to January 2023, with 500 imaging cases (335 benign and 165 malignant). A CNN was employed for automated classification. The model framework encompassed training and testing stages, with 8 layers (5 Conv and 3 FC) and ReLU activation. Essential architectural modifications included Batch Normalization (BN) after the first and second convolutional filters. Comparative experiments with various existing methods were conducted to assess algorithm performance in tumor staging. Evaluation metrics encompassed accuracy, precision, sensitivity, specificity, F-measure, ROC curves, and AUC values. ResultsThe analysis of precision, sensitivity, specificity, and F1 score from the results demonstrates that the method introduced in this paper offers several advantages, including a low feature dimension and robust generalization (with an accuracy of 98.34 %, sensitivity of 97.26 %, specificity of 95.74 %, and an F1 score of 96.37). These findings underscore its exceptional overall detection capabilities. Notably, when comparing various algorithms, they generally exhibit similar classification performance. However, the algorithm presented in this paper stands out with a higher AUC value (AUC=0.848), signifying enhanced sensitivity and more robust specificity. ConclusionThis study presents an optimized AlexNet model for classifying femoral bone tumor images based on convolutional neural networks. This algorithm demonstrates higher accuracy, precision, sensitivity, specificity, and F1-score than other methods. Furthermore, the AUC value further confirms the outstanding performance of this algorithm in terms of sensitivity and specificity. This research makes a significant contribution to the field of medical image classification, offering an efficient automated classification solution, and holds the potential to advance the application of artificial intelligence in bone tumor classification.

GHA-DenseNet prediction and diagnosis of malignancy in femoral bone tumors using magnetic resonance imaging

Background and objectiveDue to their aggressive nature and poor prognosis, malignant femoral bone tumors present considerable hurdles. Early treatment commencement is essential for enhancing vital and practical outcomes. In this investigation, deep learning algorithms will be used to analyze magnetic resonance imaging (MRI) data to identify bone tumors that are malignant. MethodologyThe study cohort included 44 patients, with ages ranging from 17 to 78 (22 women and 22 males). To categorize T1 and T2 weighted MRI data, this paper presents an improved DenseNet network model for the classification of bone tumor MRI, which is named GHA-DenseNet. Based on the original DenseNet model, the attention module is added to solve the problem that the deep convolutional model can reduce the loss of key features when capturing the location and content information of femoral bone tumor tissue due to the limitation of local receptive field. In addition, the sparse connection mode is used to prune the connection mode of the original model, so as to remove unnecessary and retain more useful fast connection mode, and alleviate the overfitting problem caused by small dataset size and image characteristics. In a clinical model designed to anticipate tumor malignancy, the utilization of T1 and T2 classifier output values, in combination with patient-specific clinical information, was a crucial component. ResultsThe T1 classifier's accuracy during the training phase was 92.88% whereas the T2 classifier's accuracy was 87.03%. Both classifiers demonstrated accuracy of 95.24% throughout the validation phase. During training and validation, the clinical model's accuracy was 82.17% and 81.51%, respectively. The clinical model's receiver operating characteristic (ROC) curve demonstrated its capacity to separate classes. ConclusionsThe proposed method does not require manual segmentation of MRI scans because it makes use of pretrained deep learning classifiers. These algorithms have the ability to predict tumor malignancy and shorten the diagnostic and therapeutic turnaround times. Although the procedure only needs a little amount of radiologists' involvement, more testing on a larger patient cohort is required to confirm its efficacy.

NUT carcinoma, an under-recognized malignancy: a clinicopathologic and molecular series of 6 cases showing a subset of patients with better prognosis and a rare ZNF532::NUTM1 fusion

NUT carcinoma (NC) is a rare malignancy with aggressive clinical behavior, defined by rearrangements involving the NUTM1 gene locus. This entity is often under-recognized and its diagnosis may be challenging. In this study, we describe a subset of patients that, despite the molecularly proven diagnosis of NC, show improved outcomes. In addition, we describe one case with the novel ZNF532::NUTM1 fusion. All cases of NC diagnosed from 2013 to 2022 in our department were retrieved. FISH using dual color bring-together probes and next-generation sequencing assay were performed to characterize the fusions involving NUTM1. Among6 patients identified, 5 were men with a median age of 35.6 years. Four patients had primary tumors in the head and neck region (2 ethmoid sinus, 1 parotid gland, and 1 lacrimal gland); 1 in the mediastinum, and another presented with a femoral bone tumor. In all cases, the initial diagnoses were not NC. The cases showed different morphological patterns, including monomorphic, rhabdoid, and pleomorphic appearances. One case showed a pseudopapillary pattern. By immunohistochemistry, all tumors showed squamous differentiation and ≥50% of neoplastic cells with nuclear positivity for NUT antibody. One case expressed WT1 (C-terminus) and other showed chromogranin positivity. Genetic study revealed a BRD4::NUTM1 fusion in all head and neck cases, BRD3::NUTM1 in mediastinum case, and ZNF532::NUTM1 fusion in the femur bone case. They were treated with surgical resection plus chemotherapy and radiotherapy. The median overall survival was 23.11 months (1.6-83.3months) and the median disease-free survival was 14.86 months (0-54.4months). The patients with longer overall survival were one with a lacrimal gland primary (83.3 months) and other with a parotid lesion (31.9 months). Both patients were primarily treated with complete surgical resection. Anatomic location may be directly related to the overall survival in NC cases. Resectability of the lesion is also an important factor related to survival. Pathologists should include NC in the differential diagnosis of any poorly differentiated and undifferentiated monomorphic malignancy, regardless of its anatomic location.

Clinical Application of Artificial Intelligence: Auto-Discerning the Effectiveness of Lidocaine Concentration Levels in Osteosarcoma Femoral Tumor Segment Resection.

Adolescents and children worldwide are threatened by osteosarcoma, a tumor that predominantly affects the long bone epiphysis. Osteosarcoma is the most common and highly malignant bone tumor in youngsters. Early tumor detection is the key to effective treatment of this disease. The discovery of biomarkers and the growing understanding of molecules and their complex interactions have improved the outcome of clinical trials in osteosarcoma. This article describes biomarkers of osteosarcoma with the aim of positively influencing the progress of clinical treatment of osteosarcoma. Femoral bone tumor is a typical condition of osteosarcoma. Due to the wide range of femoral stem types, complexities in the distal femur, and tumors in the rotor part of femur, physicians following the traditional clinical approach face difficulties in removing the lesion and fixing the femur with resection of the tumor segment. In this paper, the effect of small doses of different concentrations of lidocaine anesthesia in patients undergoing lumpectomy for osteosarcoma femoral tumor segments is investigated. A computer-based artificial intelligence method for automated determination of different concentration levels of lidocaine anesthesia and amputation of osteosarcoma femoral tumor segment is proposed. Statistical analysis is carried on the empirical data including intraoperative bleeding, intraoperative and postoperative pain scores, surgical operation time, postoperative complications, patient satisfaction, and local anesthetic dose. The results showed that the patients in the study group had low intraoperative bleeding, short operation time, low postoperative hematoma formation rate, high patient satisfaction, higher dosage of anesthetic solution, and low dosage of lidocaine. Results revealed that mean arterial pressure and heart rate in extubating and intubating were significantly lower in the observation group than in the control group, and a significant difference (P < 0.05) was observed between the two groups. This proves that the proposed algorithm can adequately reduce bleeding, alleviate postoperative pain, shorten operation time, reduce complications, accelerate recovery, and ensure better treatment results.

Clinical Outcomes of Artificial Total Hip Arthroplasty for Proximal Femoral Bone Tumors

Objective: To investigate the clinical outcome of artificial hip replacement for proximal femoral bone tumors. Methods: One hundred patients with proximal femur bone tumors admitted to the hospital for treatment from June 2018 to May 2020 were selected and divided into a control group and an experimental group of 50 patients each using central randomization. The control group received conventional treatment and the experimental group underwent artificial total hip arthroplasty, and the results of treatment were compared between the two groups. Results: The operative time and hospitalization time of the experimental group were shorter than that of the control group, and the blood loss was less than that of the control group; after the replacement surgery, the range of flexion and extension, internal and external rotation activity and abduction activity scores were better than those of the control group; and the total incidence of adverse reactions in the experimental group was 6.0%, which was significantly lower than that of the control group (14.0%). By comparing the treatment effects of the two groups, the differentiation was significant, and P&lt;0.05 was statistically significant. Conclusion: Artificial hip arthroplasty can effectively treat proximal femoral tumors, shorten operative time, hospitalization time and intraoperative bleeding, and alleviate patients' therapeutic pain, which has good promotion value in clinical practice.

Intralesional curettage versus prosthetic replacement for bone tumors — a finite element analysis case of limb salvage simulation in biomechanics

Background and objectivesTo compare mechanical properties of femoral tumor treatments so that better operative strategy for limb tumors surgery is optimized. MethodsFourteen femoral CT images were randomly selected to rebuild 3D models by MIMICS. They were then executed by reverse engineering softwares for simulative modes. Mode #1: Intralesional curettage with cement filled plus fixator; Mode #2: Distal femur resection with tumorous prosthesis replaced. Finally, the mechanical aspects such as stress and displacement were compared by finite element analysis. ResultsAnalyzed by AnSys, the observation indexes were measured as follows: for displacement of femurs, d=1.4762 (< a=3.9042 < c=3.9845 < b=4.1159) in mm is the most staple of all models; for displacement of implants (fixators or prostheses), it's similar to the behavior of femurs and with no significant difference; for stresses of femurs, no significant difference was found among all models; the stresses of implants (fixations and prostheses) were observed as d=39.6334 (< a=58.6206 < c=61.8150 < b=62.6626) in MPa correspondently, which is the least; for stresses of the general system, the average of peak values for integrated devices of all models are: d=40.8072 (< a=58.6206 < c=61.7831< b=62.6626) in MPa, which is also the least. As a final result, both maximum values for displacement and stress of mode 2 are lower than those of mode 1. ConclusionsOur finite element analysis of limb salvage simulation in biomechanics proved that, to treat distal femoral bone tumors, prosthetic replacement is more efficient than intralesional curettage.

A report of three cancer patients on opioid analgesia receiving spinal anesthesia: abrupt pain elimination without respiratory depression

BackgroundComplete removal of pain with regional anesthesia has been reported to cause fatal respiratory depression in opioid-dependent patients, which leads us to choose general anesthesia. We hereby report three cases of chronically opioid-treated cancer patients operated under spinal anesthesia without respiratory event.Case presentationCase 1: a 32-year-old female treated with high-dose morphine for her cancer pain was planned for cesarean section. Case 2: a 65-year-old female on moderate dose of oxycodone was planned for surgery of her femoral bone fracture. Case 3: a 65-year-old male on low-dose oxycodone was planned for intramedullary nailing for metastatic femoral bone tumor. In all three cases, spinal anesthesia was chosen. Continuous respiratory monitoring revealed no apnea or bradypnea.ConclusionSpinal anesthesia was safely performed without respiratory depression in chronic opioid users for cancer pain.

Clinical evaluations of diaphysis malignant tumors of femur and tibia treated with microwave ablation in situ

BackgroundThis study was designed to evaluate the clinical outcomes of patients with diaphysis malignant tumors of femur and tibia treated with microwave ablation (MWA) in situ.MethodsRetrospective study of 32 patients with diaphysis malignant bone tumors of femur or tibia have been treated by microwave ablation. Instead of en bloc resection, hyperthermia ablation in situ was carried out followed by strengthen procedure. The patients were followed up for a period ranging from 36 to 180 months.ResultsTwenty-five patients survived over 3 years and all of the patients alive have a satisfactory functional and cosmetic limb. The postoperative survival rate of MWA group was significantly higher than the amputation group in consecutive inclusions.ConclusionsMWA is a feasible and effective surgical method for limb salvage operation and it might offer an innovative and distinctive therapeutic alternative for diaphysis malignant bone tumors, which avoiding osteotomy or prosthesis replacement.Level of evidenceLevel IV, clinical cohort study

Fixed-hinge cemented modular implants: An effective reconstruction technique following primary distal femoral bone tumor resection. A 136-case multicenter series

BackgroundReconstruction by endoprosthesis is widespread after bone tumor resection. The design and type of fixation and of hinge remain a matter of debate. The aim of the present study was to assess survival, complications and functional results in a homogeneous series of adult patients undergoing bone defect reconstruction following distal femoral tumor resection, using a single model of fixed-hinge cemented endoprosthesis, at a minimum 5 years’ follow-up. HypothesisThe study hypotheses were that loosening and infection are the main causes of failure, and that this type of reconstruction is reliable following distal femoral resection. Patients and methodsAll patients aged over 17 years undergoing reconstruction using the Stanmore Mets® fixed-hinge cemented modular endoprosthesis following distal femoral resection for primary bone tumor in 4 French reference centers between 2004 and 2013 were included. Epidemiological data, MSTS functional score, clinical and radiological examination results, complications and survival with types of failure according to the Henderson classification were assessed. ResultsOne hundred and thirty-six patients (68 male, 68 female; mean age, 41.2 years [range, 17–77 years]) were included. Mean follow-up was 81 months [range, 61–134 months]. Thirty-two patients (38%) experienced a total 67 complications requiring surgical revision: mainly infection (n=28) or mechanical failure (n=26). Overall implant survival was 78% at 5 years. There were 30 implant failures on the Henderson classification. Mean MSTS score was 82%. DiscussionThe present results are comparable to those of the literature and for other types of reconstruction. Recent meta-analyses suggest that type of hinge and of stem fixation have little effect on implant survival. International comparative studies are needed to determine the exact role of each type of reconstruction according to the patient profile. Level of evidenceIV, multicenter retrospective series.

MRI examination of resected malignant bone tumor can be an option for assessment of the osseous surgical margin.

Confirming the surgical osseous margin of a resected malignant bone tumor macroscopically before reconstruction with a prosthesis is ideal. However, making the cut-surface of the femur specimen during surgery is difficult because of the hard bone tissue. In order to resolve this problem, the possibility of intraoperative MRI was considered. MRI was performed at the surgical unit for five malignant femoral bone tumors that included two osteosarcomas and one undifferentiated high-grade sarcoma, and two metastatic tumors immediately after the tumor resection. The specimens were prepared in plastic containers with saline. The osseous surgical margins were confirmed to be those planned pre-operatively in all cases without metal-induced artifacts. The T1 weighted image (WI) was useful for evaluation of the osseous surgical margin, whereas the T2WI was useful for confirmation of extraosseous soft-tissue. The MRI was performed post-operatively as a preliminary evaluation of the technique. However, a limited sequence (i.e. coronal T1WI) with short examination time could be performed during surgery for the sole purpose of assessing the osseous margin. MRI examination of a resected malignant bone tumor specimen has not been reported, and can be an option for assessment of the osseous surgical margin.

Long-Term Follow-Up in Tumoral Arthroplasty

Abstract Introduction. Efficient management of a segmental resection or major osteolysis in the distal femur secondary to a tumor formation remains a controversial problem. Available options include the use of a modular or customized megaprosthetic implant. Modularity allows versatility for reconstruction and avoids the delay required to make a customized implant. Hypothesis and type of study. Performing a clinical and radiological retrospective study that aims to evaluate long-term efficiency in the use of megaprostheses in segmental distal femur resections. Elaboration of patient selection criteria for modular prosthesis. Materials and methods. We followed retrospectively 33 patients for 5 years from the time of the first surgery. We evaluated the implant stability, the late complications rate, and the long-term functional recovery of patients with distal femoral tumors who underwent segmental resections and subsequently reconstructive arthroplasty. Results. Thirty of the 33 patients maintained a mobile knee joint. An intermediate staging was performed at 30 months, which determined tumor recurrence in 2 patients, aseptic degradation of the components in 3 of them, and septic degradation in two of the evaluated cases. Because a tumoral recurrence occurred on the 45th month, the need for amputation of the prosthetic limb was imposed. The degradation of the polyethylene component (in 5 cases) was observed in the 5-year assessment. The functional results were excellent with the Musculoskeletal Tumor Society Score of 88% and a Toronto Extremity Severity Scale Score of 94%. Conclusions. Patients with distal femoral bone tumors undergoing modular reconstruction prosthetic arthroplasty have excellent functional results with retaining the affected limb and knee mobility. There was a close correlation between correctly applying the selection criteria for patients undergoing prosthesis intervention and functional recovery results.

Primary arthroplasty in healed osteoarticular allograft in patients with history of primary femoral bone tumors

BackgroundRoughly 25–35% of patients who are treated with osteoarticular allograft for primary bone sarcomas or aggressive benign bone tumors require surgery in the long-term due to degenerative changes of the articular surface of the allograft. There are three established methods of reconstruction for this complication; a total hip arthroplasty (THA) or total knee arthroplasty (TKA) in the retained osteoarticular allograft, a proximal or distal endoprosthesis after removal of the allograft, and an allograft-prosthesis composite (APC). The aims of this study are 1) to determine the rate of complication and failure of THA/TKA in healed femoral allograft; 2) to compare the methods of revision for allograft degeneration; and 3) to compare the use of arthroplasty in healed allograft to that of arthroplasty in native bone. MethodsWe included all patients with primary bone sarcomas and locally aggressive primary benign bone tumors treated between 1984 and 2014 with an osteoarticular allograft followed by any subsequent arthroplasty technique as described above. Complications and reasons for failure are described following the classification of Henderson et al. Failure was defined as any complication leading to removal of the initial treatment construct. Failure rates of these groups were compared to primary arthroplasty in a live host bone (Control Group). ResultsComplications happened in 25 (61.0%) of the patients with a THA/TKA in the retained allograft, of these, 24 (58.5%) experienced failure, the most common being structural failure/type III (14, 58.3%). Thirteen patients (81.3%) with an endoprosthesis after removal of the allograft experienced complications, all of whom failed. The most common failure modes were aseptic loosening/type II (4, 30.8%) and infection/type IV (5, 38.5%). Complications in patients with an APC were experienced by 12 (85.7%) patients, 11 (78.6%) of whom failed. The most common failure mode was infection/type IV (4, 36.4%). Significantly (p < 0.001) fewer failures were observed in the control group compared to patients with an arthroplasty in a healed allograft. ConclusionsWe found no significant difference in the outcome of treating patients with allograft and subsequent degenerative bone disease with a THA/TKA in a retained allograft, an endoprosthesis after removal of the allograft, or a primary APC, although infection is a significantly greater cause of failure in the latter two. Primary arthroplasty in healed allografts is a less extensive surgery than removing the allograft and shows comparable complication and failure rates. Level of evidenceLevel III, Therapeutic Study.

Long-term Results of Osteoarticular Allograft Reconstruction in Children with Distal Femoral Bone Tumors.

There is no consensus regarding the best method of reconstruction in pediatric population following the wide resection of malignant bone tumors. More exploration of the complications of osteoarticular reconstruction leads to less existing controversy of this type of reconstruction, which is the main point of this article. Long-term outcomes and complications of osteoarticular allograft reconstruction of primary distal femoral bone sarcomas in 22 children with mean age of 10.7 years old were reviewed in this study. Musculoskeletal Tumor Society (MSTS) scoring system was used for functional evaluation of the allografts. With an average follow-up time of 81 months, the outcomes of 16 patients with allografts at the final follow up were evaluated. As expected, Limb length discrepancy (LLD) was observed in all patients (mean LLD= 2.73cm), which was significantly correlated to allograft survival time (P<0.001). Degenerative joint disease (DJD) was also seen in all patients and its grade was also significantly correlated to allograft survival time (P<0.001). The mean MSTS-score was 74% at the latest follow-up, ranging from 60% to 90%. Five and 10 year survival rate of allografts were found to be 93.3% and 62.2%, respectively. Osteoarticular allograft reconstruction could result in several complications including DJD. Despite its considerable biologic advantage over endoprosthesis, osteoarticular allograft reconstruction is a long-lasting but still a temporary solution before performing megaprosthesis. This allows patients to preserve their remaining physis for limb growth and become old enough for an adult megaprosthesis.

Hydroxyapatite-coated collars reduce radiolucent line progression in cemented distal femoral bone tumor implants.

Aseptic loosening of massive bone tumor implants is a major cause of prosthesis failure. Evidence suggests that an osteointegrated hydroxyapatite (HA)-coated collar would reduce the incidence of aseptic loosening around the cemented intramedullary stem in distal femoral bone tumor prostheses. Because these implants often are used in young patients with a tumor, such treatment might extend the longevity of tumor implants. Questions/purposes We asked whether (1) HA-coated collars were more likely to osteointegrate; (2) HA collars were associated with fewer progressive radiolucent lines around the stem-cement interface; and (3) HA-coated collars were associated with less bone loss at the bone-shoulder implant junction? Twenty-two patients were pair-matched to one of two groups--either (1) implants with a HA-coated ingrowth collar (HA Collar Group); or (2) implants without an ingrowth collar (Noncollar Group). Age, sex, and length of followup were similar in both groups. HA-coated collars were developed and used at our institution from 1992 to address the high failure rate attributable to aseptic loosening in patients with massive bone tumor implants. Before this, smooth titanium shafts were used routinely adjacent to bone at the transection site. The minimum followup was 2 years (mean, 7 years; range, 2-12 years). Radiographs obtained throughout the followup period were analyzed and osteointegration at the shaft of the implant quantified. Radiolucent line progression around the cemented stem was semi-quantitatively assessed and cortical bone loss at the bone-shoulder implant junction was measured during the followup period. Comparison of the most recent radiographs showed nine of 11 patients had osteointegrated HA collars, whereas only one patient in the Noncollar Group had osteointegration (p > 0.001). The radiolucent line score quantified around the cemented stem was lower in the HA Collar Group when compared with the Noncollar Group (p = 0.001). Results showed an increase in cortical bone loss at the bone-shoulder implant junction in the Noncollar Group when compared with the HA Collar Group (p < 0.001). Osteointegration at the implant collar resulted in fewer radiolucent lines adjacent to the intramedullary cemented stem and decreased cortical bone loss immediately adjacent to the transection site. These results suggest that the HA collar may help reduce the risk of aseptic loosening in patients with this type of implant, but longer followup and a larger prospective comparison series are necessary to prove this more definitively.

Modified technique using allograft-prosthetic composite in the distal femur after bone tumor resection

BackgroundThe purpose of this retrospective study was to analyze the results of treatment of bone tumor resection of the distal femur with the modified technique of allograft-prosthetic composite. MethodsTwelve patients with distal femoral bone tumors were treated with deep-frozen cortical allograft struts and allograft-prosthesis composites. There were five males and seven females with a median age of 29.5y. The minimum follow-up time was 12mo (median, 45.7mo; range, 12–81mo). Diagnoses included osteosarcoma in five patients, chondrosarcoma in three patients, giant cell tumors in three patients, and malignant fibrous histiocytoma in one patient. Five osteosarcoma patients were treated with adjuvant chemotherapy. ResultsAt the latest follow-up examination, 11 patients were alive with no evidence of disease, and the limb was preserved in nine patients. One patient died of pulmonary metastases with no evidence of local recurrence. Seven healed without complications. A surgical procedure was performed in four patients because of complications, which included a fracture (one patient), deep infection (one patient), instability (one patient), and local recurrence (one patient). ConclusionThe modified technique of allograft-prosthetic composite is an effective treatment for bone tumor resection of the distal femur. This technique has many advantages, including augmentation of the bone stock, minimizing the risk of allograft fracture and nonunion, and decreasing the need for revision operations.

Megaprosthesis versus Condyle-sparing Intercalary Allograft: Distal Femoral Sarcoma

Although functionally appealing in preserving the native knee, the condyle-sparing intercalary allograft of the distal femur may be associated with a higher risk of tumor recurrence and endoprosthetic replacement for malignant distal femoral bone tumors. We therefore compared the risk of local tumor recurrence between patients in these two types of reconstruction groups. We retrospectively reviewed 85 patients (mean age, 22 years; range, 4-82 years), 38 (45%) of whom had a condyle-sparing allograft and 47 (55%) of whom had endoprostheses. The minimum followup for both groups was 2 years (mean, 7 years; range, 2-19 years). Local recurrences occurred in 11% (five of 47) of the patients having implants versus 18% (seven of 38) of the patients having allografts. Using time to local recurrence as an end point, the Kaplan-Meier survivorship of the implant group was similar to that of the condyle-sparing allograft group at 2, 5, and 10 years (93% versus 87% at 2 years, 87% versus 81% at 5 years, and 87% versus 81% at 10 years, respectively). The condyle-sparing allograft procedure offers the potential advantage of retaining the native knee in a young patient population while incurring no greater risk of local recurrence as those offered the endoprosthetic procedure. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Experimental study of chemical embolus therapy combined with radiotherapy for VX2 bone tumors

Background. We conducted an experimental study, using a combination of coarse crystal cisplatin and radiotherapy for bone tumors, to evaluate the possibility of the clinical application of chemical embolus therapy in the field of orthopedic surgery. Methods. Experimental femoral bone tumors were produced, in rabbits, using VX2 carcinoma. The rabbits were allocated to five groups: untreated control, embolus, chemical embolus, irradiation alone, and chemical embolus and irradiation combination. These therapies were evaluated comparatively, in terms of local antitumor effects (including body weight, X-ray findings, angiography, and histopathology) and in terms of inhibition of pulmonary metastasis. Results. Local antitumor effects, as evaluated by all parameters, except for body weight, were significantly greater for the chemical and irradiation combination group than for the chemical embolus, irradiation alone, untreated control, and embolus groups. There was no significant difference in the inhibition of pulmonary metastasis among the chemical embolus and irradiation combination, chemical embolus, and irradiation alone groups. Conclusion. These findings demonstrated the synergistic effect of the combination of chemical embolus therapy and radiotherapy. In this study, however, no significant difference was found between the chemical embolus therapy alone and the combination therapy groups in the inhibitory effect on pulmonary tumor metastasis, suggesting the need to conduct combination therapy repeatedly in the clinical setting.

Disassembly of a Howmedica Modular Resection system

We report the postoperative disassociation of a Morse taper junction of a Howmedica Modular Resection system implanted after the resection of a malignant distal femoral bone tumor. The disassembly occurred without apparent trauma. This complication was managed by closed reduction under epidural anesthesia. This disassembly probably occurred because of decreased tension of the soft tissue around the prosthesis or an impaired locking mechanism.

Bony atrophy after mega total hip replacement for bone tumors. 11 cases followed for 3-15 years.

We followed 11 patients 3-15 years after a cemented mega total hip replacement for a proximal femoral bone tumor. 7/8 survivors had good function and only occasional pain. 1 hip had been revised because of deep infection and in 1 case the cup had been exchanged because of aseptic loosening. 2 patients had been operated on because of local recurrence of the tumor. At follow-up, 1 patient had radiographic signs of loosening of the stem after 7 years. There was in 8 cases a pronounced athropy of the femoral cortical bone, not correlated to loosening of the stem.