Zhuangzhuang Li

Introduction: Pulmonary metastasis in high‐grade conventional osteosarcoma remains a leading cause of treatment failure and mortality. Traditional monitoring methods are insufficient for early detection. This study aims to develop and validate an interpretable machine learning (ML) model using multi‐dimensional data from electronic medical records (EMR) to predict the early risk of pulmonary metastasis in high‐grade conventional osteosarcoma patients. Methods: This retrospective study included data from 522 high‐grade conventional osteosarcoma patients. After rigorous feature selection, 12 independent predictive factors were identified: prothrombin time (PT), international normalized ratio (INR), fibrinogen, globulin, prognostic nutritional index (PNI), eosinophil percentage, monocyte percentage, neutrophil percentage, monocyte count, maximum tumor diameter, gender, and amputation status. Eleven ML models were constructed and compared, with Shapley Additive Explanations (SHAP) analysis applied to enhance model interpretability and clinical transparency. Results: The gradient boosting model exhibited superior performance, achieving an area under the curve (AUC) of 0.891 in the training set and 0.742 in the independent test set. SHAP analysis revealed that tumor maximum diameter was the most influential predictor of pulmonary metastasis risk, while inflammation and coagulation‐related indicators also demonstrated significant contributions. Discussion: The gradient boosting model effectively predicts the early risk of pulmonary metastasis in high‐grade conventional osteosarcoma and provides interpretable risk factors. This model shows potential as a clinical decision support tool, facilitating personalized risk management and precision medicine, aiming to improve patient outcomes.

Background: Parosteal osteosarcoma (PAOS) is a rare and low‐grade primary bone malignant tumor that typically occurs in the distal femur. Traditional reconstruction options for distal femur PAOS include distal femoral replacement (DFR), autografts, and allografts, but issues such as functional sacrifice, insufficient mechanical strength, and low bone union rate limit their further clinical application. 3D‐printed prosthesis, due to the matching shape of various bone defects, could be a novel strategy to reconstruct the hemicortical defect after distal femur PAOS tumor resection. In this study, we designed a 3D‐printed strut‐type prosthesis (3DPSP) to repair the hemicortical defect and evaluated the mid‐term effect in distal femur PAOS. Methods: A retrospective analysis was conducted on patients diagnosed with PAOS at the distal femur between April 2018 and January 2021. Six patients received DFR and six patients received customized 3DPSP reconstruction. Clinical outcomes including oncology status, defect lengths, and ranges of motion of the knee, Musculoskeletal Tumor Society (MSTS) scores, and complications were recorded. X‐ray was performed to evaluate the position and stability of the prosthesis and T‐SMART was applied to assess the interface osteointegration between prosthesis and bone. Results: A total of 12 patients were enrolled in this study with an average follow‐up of 42.1 ± 11.8 months, ranging from 22 to 59 months. In the 3DPSP group, the average operation time was 2.3 ± 0.4 h; the intraoperative blood loss was 175.0 ± 82.2 mL. The average range of motion of the knee was 0°–123° and the mean MSTS score was 28.3 ± 1.6. Compared to the DFR group, the 3DPSP group exhibited significantly less intraoperative blood loss and superior functional recovery. Conclusions: In this study, we designed a novel 3DPSP to reconstruct the hemicortical defect after distal femur PAOS resection. The mid‐term follow‐up result demonstrated that this prosthesis could be an effective reconstruction option for distal femur PAOS patients because of the restored limb function and favorable bone‐prosthesis integration. Further observation of this novel prosthesis is needed.

Objective: Durable and biologically integrated fixation is critical for long‐term implant survival in patients with primary bone tumors. However, limited evidence exists regarding the long‐term outcomes of uncemented stem designs in this population. Specifically, we investigated: (1) the long‐term patient and implant survivorship rates; (2) the influence of factors such as resection length and patient age on implant survival; and (3) the incidence and types of complications, particularly those requiring implant removal or revision.Methods: We retrospectively reviewed 76 patients (49 males, 27 females; mean age 41 years, range 14–78 years) who underwent proximal femoral replacement with a modular uncemented endoprosthesis between 2015 and 2022. The mean follow‐up was 63.4 months (median: 60.5 months; range: 12–104 months). Functional outcomes were assessed using the Musculoskeletal Tumor Society (MSTS) score, while complications were classified based on the Henderson et al. system. Survivorship analyses were conducted using Kaplan–Meier methods.Results: The 5‐year patient survival rate was 88.0%, and the 5‐year implant survival rate was 90.4%. The mean MSTS score at final follow‐up was 25.6 (range 16–30), with 87.7% of patients achieving good to excellent functional outcomes. Younger patients (< 30 years) exhibited poorer implant survival, while resection length did not significantly impact outcomes. Complications occurred in 18.4% of cases, categorized into type 1 (soft tissue‐related, n = 3), type 2 (aseptic loosening, n = 2), type 3 (structural failure, n = 0), type 4 (infection, n = 3), type 5 (tumor recurrence, n = 3), and three cases of acetabular failure.Conclusions: Modular uncemented endoprostheses for proximal femoral replacement demonstrated promising survivorship and functional outcomes in patients with primary bone tumors. The low rate of aseptic loosening highlights the benefits of uncemented stem designs. However, younger age remains a risk factor for reduced implant longevity.

Objective: Type III hemipelvectomy and reconstruction are challenging. Several reconstruction options, including autologous soft tissue, prosthesis patch, autologous, or allograft, were reported, but a variety of shortcomings limited their application. Three‐dimensional (3D)‐printed prosthesis was designed to reconstruct the unilateral Type III pelvic defect and had favorable clinical outcomes. However, the reconstruction method for bilateral Type III pelvic defect was few reported. This study aims to design a bilateral pubis prosthesis and evaluate the early clinical outcomes and complications.Methods: We retrospectively collected patients receiving 3D‐printed bilateral pubis prosthesis reconstruction after malignant tumor resection between 2017 and 2021. Demographics, anatomic data, operation time, blood loss, and clinical outcomes of patients were analyzed. The Musculoskeletal Tumor Society‐93 (MSTS‐93) score was performed to evaluate the function and complications were recorded.Results: Four patients, including three for females and one for males, were enrolled in this study. Prosthesis was designed according to the pelvic anatomical data. The mean operation time and blood loss were 308.8 min (range, 240–400 min) and 655 mL (range, 400–1100 mL), respectively. The average follow‐up was 15.5 months (range, 12–16 months). The mean MSTS was 28.5 (28–29). One patient had incision necrosis postoperatively. No hernia, prosthesis displacement, or implant failure occurred during follow‐up. Four patients with 15 interfaces showed good osteointegration.Conclusions: 3D‐printed bilateral pubis prosthesis could restore the integrity and stability of pelvic ring and improve limb function. Meanwhile, this reconstruction option provided a rigid bony‐soft support to prevent the development of hernia. In all, 3D‐printed bilateral pubis prosthesis is recommended to be a favorable selection for Type III pelvic defect reconstruction.

Objective: Osteosarcoma at the first metacarpal is extremely rare. Reconstructing the metacarpal after tumor resection is essential, as the thumb accounts for approximately 40%–50% of hand function. Although autografts, arthroplasty, and transposition have been reported as reconstruction options, their use is limited by complications such as secondary injury, nonunion, and displacement. In this study, we present a case of a patient with first metacarpal osteosarcoma who underwent tumor resection followed by reconstruction with a 3D‐printed metacarpal prosthesis. We tend to introduce a novel strategy to reconstruct the first metacarpal and restore the hand function.Methods: A 30‐year‐old male with 5‐month history of first metacarpal swelling in the left hand was admitted to our center. Imaging examinations and incision biopsy confirmed a diagnosis of intramedullary well‐differentiated osteosarcoma. A 3D‐printed metacarpal prosthesis was then designed to achieve carpometacarpal (CMC) joint fusion and thumb metacarpophalangeal (MCP) joint reconstruction. Postoperative evaluations included X‐ray and tomosynthesis‐shimadzu metal artifact reduction technology (T‐SMART) imaging to assess bone‐prosthesis integration. Hand function was measured using the Musculoskeletal Tumor Society (MSTS) score and the Disabilities of the Arm, Shoulder, and Hand (DASH) score.Results: The tumor was completely resected, and a 3D‐printed metacarpal prosthesis was performed to reconstruct the tumor defect. Postoperative imaging showed that the interface between bone and prosthesis was integrated and that there was no loose, displacement, or fracture of the implant. At the last follow‐up, the patient had an MSTS score of 25/30 and a DASH score of 8/100. The range of motion on thumb MCP joint was 30° of flexion and 0° of extension. The Kapandji thumb opposition score was 4 points. The grip strength was 9 kg (compared to 30 kg on the contralateral side) and the key‐pinch strength was 3 kg (compared to 8 kg on the contralateral side).Conclusion: 3D‐printed metacarpal prosthesis could be an effective reconstruction option for patients with low‐grade malignant tumors. Themulti‐planar fixation achieved through 3D surgical planning helps maintain thumb function and restore overall hand function.

Background: Malignant tumors originating in the talus are rare and present significant challenges in reconstruction. Traditional treatments, such as below‐knee amputation or tbiocalcaneal fusion, often result in significant loss of ankle function. After tumor resection, reconstruction of the talus and calcaneus is necessary to preserve ankle function. However, the intricate anatomical structure and unique location of the talus and calcaneus present significant challenges for prosthetic reconstruction.Case Presentation: Here, we present the case of an 11‐year‐old adolescent patient diagnosed with Ewing's sarcoma of the talus, accompanied by suspected involvement of the calcaneus. Following a comprehensive evaluation, a 3D‐printed talus‐calcaneus prosthesis, which is composed of a ultrahigh‐molecular weight polyethylene (UHMWPE) part and a titanium alloy part, was designed for talus and calcaneus reconstruction. In addition, a porous structure was designed to promote the integration of bone–prosthesis interface. The lesion was completely resected and the prosthesis was precisely installed. After 12 months follow‐up, patients demonstrated favorable function results with the Musculoskeletal Tumor Society (MSTS) score was 27/30, and the American Orthopedic Foot and Ankle Society (AOFAS) score was 92/100. The range of motion for dorsiflexion, plantarflexion, inversion, and eversion of the right ankle joint was measured as 10° and 35°, 15°, and 10°, respectively. The postoperative radiograph showed a good position of the prosthesis. No narrowed joint space was observed. Tomosynthesis shimadzu metal artifact reduction technology (T‐SMART) revealed that integration between bone and prosthesis was good.Conclusion: In this case, we present a case of 3D‐printed talus‐calcaneal prosthesis reconstructing talus and calcaneus. Favorable postoperative function outcome and good integration of the interface were observed. Therefore, this case provides an alternative therapeutic option for the treatment invasive talus tumor accompanied by suspicious contamination of the calcaneus. Nevertheless, a larger cohort study and with longer follow‐up is needed to evaluate the effectiveness and potential complications of this novel prosthesis.

Objective: Periacetabular tumors, especially in young to middle‐aged patients with invasive benign tumors or low‐grade malignant tumors involving type II or II + III, present significant challenges due to their rarity and the complexity of the anatomical and biomechanical structures involved. The primary difficulty lies in balancing the need to avoid unfavorable oncological outcomes while maintaining postoperative hip joint function during surgical resection. This study aimed to evaluate the effectiveness and reliability of a surgical method involving partial weight‐bearing acetabular preservation combined with the use of an uncontaminated femoral head autograft to reconstruct the segmental bone defect after intra‐articular resection of the tumorous joint, providing a solution that ensures both oncological safety and functional preservation of the hip joint in these patients.Methods: We conducted a retrospective study with a follow‐up period of at least 36 months. From January 2010 to October 2020, we reviewed 20 cases of patients under 60 year of age with periacetabular invasive benign tumors or primary low‐grade malignant tumors. All patients underwent reconstruction of the tumorous joint using autologous femoral head grafts. Data collected included patient age, gender, tumor type, preoperative and postoperative visual analog scale (VAS) scores, Musculoskeletal Tumor Society (MSTS) scores, Harris Hip Scores (HHS), patient survival rates, postoperative tumor recurrence, and surgical complications. To analyze the data, we utilized various statistical methods, including descriptive statistics to summarize patient demographics and clinical characteristics, and paired sample t‐tests to compare preoperative and postoperative scores.Results: The study included 20 patients, and a total median follow‐up was 83 months. Their pathologic diagnoses comprised 13 giant cell tumors (GCTs), 5 chondrosarcomas, one chondroblastoma, and 1 leiomyosarcoma. Postoperatively, the median differences in vertical and horizontal center of rotation (COR) were 3.8 and 4.0 mm. Median limb length discrepancy (LLD) postoperatively was 5.7 mm (range, 2.3–17.8 mm). Two patients (10%) experienced delayed wound healing, resolved with antibiotics and early surgical debridement. One patient experienced dislocation 3 months postoperatively, which was promptly addressed under general anesthesia without further dislocation.Conclusion: Through multiplanar osteotomy with limited margins, femoral head autograft, and uncemented total hip replacement for pelvic segmental bone defects in selected patients in type II or II + III appears to be an encouraging limb‐sparing surgery worthy of consideration for carefully selected patients.

Objective: Management of extensive acetabular bone defects in total hip arthroplasty (THA) remains challenging. This study aims to investigate the feasibility and preliminary outcomes of 3D‐printed personalized porous acetabular components for the reconstruction of acetabular defects in primary THA.Methods: This retrospective study involved seven patients who received 3D‐printed acetabular components in primary THA between July 2018 and March 2021. Preoperatively, acetabular bone defects were evaluated by referencing the Paprosky classification. There were two "Paprosky type IIIA" defects and five "Paprosky type IIIB" defects. The acetabular components were custom‐made for each patient to reconstruct the extensive acetabular defects. The hip function was assessed according to the Harris hip score (HHS). Clinical and radiographic outcomes were assessed.Results: The average follow‐up period was 40 months, ranging from 26 to 57 months. There were no patients lost to follow‐up. The HHS improved from 44 (range: 33–53) before the operation to 88 (range: 79–93) at the final follow‐up. Postoperative X‐rays showed that the 3D‐printed personalized components were properly fitted with the acetabulum. The average center of rotation (COR) discrepancy was 2.3 mm horizontally and 2.1 mm vertically, respectively. Tomosynthesis‐Shimadzu metal artifact reduction technology images showed that the implant was in close contact with the host bone. Moreover, no complications were observed during the follow‐up period, including loosening, dislocation, or component protrusion.Conclusion: The implantation of 3D‐printed personalized acetabular components showed accurate reconstruction, stable mechanical support, and favorable function at short‐term follow‐up. This may be a viable alternative method for reconstructing extensive acetabular defects in THA.

Background: The advent of three‐dimensional (3D)‐printed custom‐made implants has revolutionized orthopaedic surgery, particularly in limb‐ and joint‐sparing surgeries. However, clinical experience in the revision for 3D‐printed implant breakage is lacking, and the revision surgery remains challenging. This study reported the revision of proximal tibial prosthetic reconstruction necessitated by solid‐body breakage of a 3D‐printed implant, aiming to detail the surgical techniques and evaluate postoperative outcomes.Case Presentation: A patient diagnosed with osteosarcoma underwent joint‐sparing surgery with a 3D‐printed implant, but implant breakage occurred during subsequent follow‐up. The initial implant was broken into two parts: the proximal implant breakage part (IBP) integrated with the host bone and the distal IBP left in the prosthetic component. Four revision protocols were devised, each based on one of the four hypothesis results of taking out the initial implant. A new custom‐made implant and a series of assistance devices (“positioning devices,” “drill devices,” “tap devices,” and “separator devices”) were specifically prepared for revision surgery. The proximal IBP was taken out from the host bone, but the distal IBP was not taken out from the initial prosthetic component. The patient received the new custom‐made implant for reconstruction, with the knee joint preserved. The patient recovered uneventfully after revision surgery and achieved satisfactory function. The Musculoskeletal Tumor Society was 28 at the last follow‐up. No complications were detected during the follow‐up period.Conclusion: Comprehensive preoperative planning and preparation, enabling the surgeon to effectively address intraoperative challenges, are crucial for the successful revision of 3D‐printed implant breakage. It is feasible to re‐implant a 3D‐printed custom‐made implant, demonstrating satisfactory clinical and functional results.