Three-dimensional printed custom-made modular talus prosthesis in patients with talus malignant tumor resection.

BACKGROUND: Talar malignant tumor is extremely rare. Currently, there are several alternative management options for talus malignant tumor including below-knee amputation, tibio-calcaneal arthrodesis, and homogenous bone transplant while their shortcomings limited the clinical application. Three-dimensional (3D) printed total talus prosthesis in talus lesion was reported as a useful method to reconstruct talus, however, most researches are case reports and its clinical effect remains unclear. Therefore, the current study was to explore the application of 3D printed custom-made modular prosthesis in talus malignant tumor. METHODS: We retrospectively analyzed the patients who received the 3D printed custom-made modular prosthesis treatment due to talus malignant tumor in our hospital from February 2016 to December 2021. The patient's clinical data such as oncology outcome, operation time, and volume of blood loss were recorded. The limb function was evaluated with the Musculoskeletal Tumor Society 93 (MSTS-93) score, The American Orthopedic Foot and Ankle Society (AOFAS) score; the ankle joint ranges of motion as well as the leg length discrepancy were evaluated. Plain radiography and Tomosynthesis-Shimadzu Metal Artefact Reduction Technology (T-SMART) were used to evaluate the position of prosthesis and the osseointegration. Postoperative complications were recorded. RESULTS: The average patients' age and the follow-up period were respectively 31.5 ± 13.1 years; and 54.8 months (range 26-72). The medium operation time was 2.4 ± 0.5 h; the intraoperative blood loss was 131.7 ± 121.4 ml. The mean MSTS-93 and AOFAS score was 26.8 and 88.5 respectively. The average plantar flexion, dorsiflexion, varus, and valgus were 32.5, 9.2, 10.8, and 5.8 degree respectively. One patient had delayed postoperative wound healing. There was no leg length discrepancy observed in any patient and good osseointegration was observed on the interface between the bone and talus prosthesis in all subjects. CONCLUSION: The modular structure of the prosthesis developed in this study seems to be convenient for prosthesis implantation and screws distribution. And the combination of solid and porous structure improves the initial stability and promotes bone integration. Therefore, 3D printed custom-made modular talus prosthesis could be an alternative option for talus reconstruction in talus malignant tumor patients.

Is 3D-printed self-stabilizing endoprosthesis reconstruction without supplemental fixation following total sacrectomy a viable approach for sacral tumours?

PURPOSE: The spinopelvic reconstruction poses significant challenges following total sacrectomy in patients with malignant or aggressive benign bone tumours encompassing the entire sacrum. In this study, we aim to assess the functional outcomes and complications of an integrated 3D-printed sacral endoprostheses featuring a self-stabilizing design, eliminating the requirement for supplemental fixation. METHODS: We retrospectively analyzed patients with sacral tumours who underwent total sacrectomy followed by reconstruction with 3D-printed self-stabilizing endoprosthesis. Clinically, we evaluated functional outcomes using the 1993 version of the musculoskeletal tumour society (MSTS-93) score. Perioperative and postoperative complications were also documented. RESULTS: 10 patients met final inclusion criteria. The median age was 49 years (range, 31-64 years). The median follow-up time was 26.5 months (range, 15-47 months). Median postoperative functional MSTS-93 was 22.5 (range, 13-25). The median operation time was 399.5 min (305-576 min), and the median intraoperative blood loss was and 3200 ml (2400-7800 ml). Complications include wound dehiscence in one patient, bowel, bladder, and sexual dysfunction in four patients, cerebrospinal fluid leak in one patient, and tumour recurrence in one patient. There were no mechanical complications related to the endoprosthesis at the last follow-up. CONCLUSION: The utilization of 3D-printed self-stabilizing endoprosthesis proved to be a viable approach, yielding satisfactory short-term outcomes in patients undergoing total sacral reconstruction without supplemental fixation.

3D-Printed custom-made hemipelvic endoprosthetic reconstruction following periacetabular tumor resection: utilizing a novel classification system.

BACKGROUND: Customized 3D-printed pelvic implants with a porous structure have revolutionized periacetabular pelvic defect reconstruction after tumor resection, offering improved osteointegration, long-term stability, and anatomical fit. However, the lack of an established classification system hampers implementation and progress. METHODS: We formulated a novel classification system based on pelvic defect morphology and 3D-printed hemipelvis endoprostheses. It integrates surgical approach, osteotomy guide plate and prosthesis design, postoperative rehabilitation plans, and perioperative processes. RESULTS: Retrospectively analyzing 60 patients (31 males, 29 females), we classified them into Type A (15 patients: Aa = 6, Ab = 9), Type B (27 patients: Ba = 15, Bb = 12), Type C (17 patients). All underwent customized osteotomy guide plate-assisted tumor resection and 3D-printed hemipelvic endoprosthesis reconstruction. Follow-up duration was median 36.5 ± 15.0 months (range, 6 to 74 months). The mean operating time was 430.0 ± 106.7 min, intraoperative blood loss 2018.3 ± 1305.6 ml, transfusion volume 2510.0 ± 1778.1 ml. Complications occurred in 13 patients (21.7%), including poor wound healing (10.0%), deep prosthesis infection (6.7%), hip dislocation (3.3%), screw fracture (1.7%), and interface loosening (1.7%). VAS score improved from 5.5 ± 1.4 to 1.7 ± 1.3, MSTS-93 score from 14.8 ± 2.5 to 23.0 ± 5.6. Implant osseointegration success rate was 98.5% (128/130), with one Type Ba patient experiencing distal prosthesis loosening. CONCLUSION: The West China classification may supplement the Enneking and Dunham classification, enhancing interdisciplinary communication and surgical outcomes. However, further validation and wider adoption are required to confirm clinical effectiveness.

Advanced Pelvic Girdle Reconstruction with three dimensional-printed Custom Hemipelvic Endoprostheses following Pelvic Tumour Resection.

PURPOSE: Resection of pelvic bone tumours and subsequent pelvic girdle reconstruction pose formidable challenges due to the intricate anatomy, weight-bearing demands, and significant defects. 3D-printed implants have improved pelvic girdle reconstruction by enabling precise resections with customized guides, offering tailored solutions for diverse bone defect morphology, and integrating porous surface structures to promote osseointegration. Our study aims to evaluate the long-term efficacy and feasibility of 3D-printed hemipelvic reconstruction following resection of malignant pelvic tumours. METHODS: A retrospective review was conducted on 96 patients with primary pelvic malignancies who underwent pelvic girdle reconstruction using 3D-printed custom hemipelvic endoprostheses between January 2017 and May 2022. Follow-up duration was median 48.1 ± 17.9 months (range, 6 to 76 months). Demographic data, imaging examinations, surgical outcomes, and oncological evaluations were extracted and analyzed. The primary endpoints included oncological outcomes and functional status assessed by the Musculoskeletal Tumor Society (MSTS-93) score. Secondary endpoints comprised surgical duration, intraoperative bleeding, pain control and complications. RESULTS: In 96 patients, 70 patients (72.9%) remained disease-free, 15 (15.6%) had local recurrence, and 11 (11.4%) succumbed to metastatic disease. Postoperatively, function improved with MSTS-93 score increasing from 12.2 ± 2.0 to 23.8 ± 3.8. The mean operating time was 275.1 ± 94.0 min, and the mean intraoperative blood loss was 1896.9 ± 801.1 ml. Pain was well-managed, resulting in substantial improvements in VAS score (5.3 ± 1.8 to 1.4 ± 1.1). Complications occurred in 13 patients (13.5%), including poor wound healing (6.3%), deep prosthesis infection (4.2%), hip dislocation (2.1%), screw fracture (1.0%), and interface loosening (1.0%). Additionally, all patients achieved precise implantation of customized prosthetics according to preoperative plans. T-SMART revealed excellent integration at the prosthesis-bone interface for all patients. CONCLUSION: The use of a 3D-printed custom hemipelvic endoprosthesis, characterized by anatomically designed contours and a porous biomimetic surface structure, offers a potential option for pelvic girdle reconstruction following internal hemipelvectomy in primary pelvic tumor treatment. Initial results demonstrate stable fixation and satisfactory mid-term functional and radiographic outcomes.

Biomimetic design and clinical application of Ti-6Al-4V lattice hemipelvis prosthesis for pelvic reconstruction.

OBJECTIVE: This study aims to biomimetic design a new 3D-printed lattice hemipelvis prosthesis and evaluate its clinical efficiency for pelvic reconstruction following tumor resection, focusing on feasibility, osseointegration, and patient outcomes. METHODS: From May 2020 to October 2021, twelve patients with pelvic tumors underwent tumor resection and subsequently received 3D-printed lattice hemipelvis prostheses for pelvic reconstruction. The prosthesis was strategically incorporated with lattice structures and solid to optimize mechanical performance and osseointegration. The pore size and porosity were analyzed. Patient outcomes were assessed through a combination of clinical and radiological evaluations. RESULTS: Multiple pore sizes were observed in irregular porous structures, with a wide distribution range (approximately 300-900 µm). The average follow-up of 34.7 months, ranging 26 from to 43 months. One patient with Ewing sarcoma died of pulmonary metastasis 33 months after surgery while others were alive at the last follow-up. Postoperative radiographs showed that the prosthesis's position was consistent with the preoperative planning. T-SMART images showed that the host bone was in close and tight contact with the prosthesis with no gaps at the interface. The average MSTS score was 21 at the last follow-up, ranging from 18 to 24. There was no complication requiring revision surgery or removal of the 3D-printed hemipelvis prosthesis, such as infection, screw breakage, and prosthesis loosening. CONCLUSION: The newly designed 3D-printed lattice hemipelvis prosthesis created multiple pore sizes with a wide distribution range and resulted in good osteointegration and favorable limb function.

Advancements in Photothermal Therapy Using Near-Infrared Light for Bone Tumors.

Bone tumors, particularly osteosarcoma, are prevalent among children and adolescents. This ailment has emerged as the second most frequent cause of cancer-related mortality in adolescents. Conventional treatment methods comprise extensive surgical resection, radiotherapy, and chemotherapy. Consequently, the management of bone tumors and bone regeneration poses significant clinical challenges. Photothermal tumor therapy has attracted considerable attention owing to its minimal invasiveness and high selectivity. However, key challenges have limited its widespread clinical use. Enhancing the tumor specificity of photosensitizers through targeting or localized activation holds potential for better outcomes with fewer adverse effects. Combinations with chemotherapies or immunotherapies also present avenues for improvement. In this review, we provide an overview of the most recent strategies aimed at overcoming the limitations of photothermal therapy (PTT), along with current research directions in the context of bone tumors, including (1) target strategies, (2) photothermal therapy combined with multiple therapies (immunotherapies, chemotherapies, and chemodynamic therapies, magnetic, and photodynamic therapies), and (3) bifunctional scaffolds for photothermal therapy and bone regeneration. We delve into the pros and cons of these combination methods and explore current research focal points. Lastly, we address the challenges and prospects of photothermal combination therapy.

Biomechanical and clinical outcomes of 3D-printed versus modular hemipelvic prostheses for limb-salvage reconstruction following periacetabular tumor resection: a mid-term retrospective cohort study.

BACKGROUND: Debates persist over optimal pelvic girdle reconstruction after acetabular tumor resection, with surgeons grappling between modular and 3D-printed hemipelvic endoprostheses. We hypothesize superior outcomes with 3D-printed versions, yet scarce comparative research exists. This study fills the gap, examining biomechanics and clinical results retrospectively. METHODS: From February 2017 to June 2021, we retrospectively assessed 32 patients undergoing en bloc resection for malignant periacetabular tumors at a single institution. PRIMARY OUTCOME: limb function. SECONDARY OUTCOMES: implant precision, hip joint rotation center restoration, prosthesis-bone osteointegration, and complications. Biomechanical characteristics were evaluated through finite element analysis on pelvic defect models. RESULTS: In the 3D-printed group, stress distribution mirrored a normal pelvis, contrasting the modular group with elevated overall stress, unstable transitions, and higher stress peaks. The 3D-printed group exhibited superior functional scores (MSTS: 24.3 ± 1.8 vs. 21.8 ± 2.0, p < 0.05; HHS: 79.8 ± 5.2 vs. 75.3 ± 3.5, p < 0.05). Prosthetic-bone interface osteointegration, measured by T-SMART, favored 3D-printed prostheses, but surgery time (426.2 ± 67.0 vs. 301.7 ± 48.6 min, p < 0.05) and blood loss (2121.1 ± 686.8 vs. 1600.0 ± 505.0 ml, p < 0.05) were higher. CONCLUSIONS: The 3D-printed hemipelvic endoprosthesis offers precise pelvic ring defect matching, superior stress transmission, and function compared to modular endoprostheses. However, complexity, fabrication expertise, and challenging surgical implantation result in prolonged operation times and increased blood loss. A nuanced consideration of functional outcomes, complexity, and patient conditions is crucial for informed treatment decisions. LEVEL OF EVIDENCE: Level III, therapeutic study (Retrospective comparative study).

Revision for Solid-Body Breakage of the 3D-Printed Implant Following Joint-Sparing Surgery: A Technical Note.

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.

3D-Printed Personalized Lattice Implant as an Innovative Strategy to Reconstruct Geographic Defects in Load-Bearing Bones.

OBJECTIVE: Geographic defect reconstruction in load-bearing bones presents formidable challenges for orthopaedic surgeon. The use of 3D-printed personalized implants presents a compelling opportunity to address this issue. This study aims to design, manufacture, and evaluate 3D-printed personalized implants with irregular lattice porous structures for geographic defect reconstruction in load-bearing bones, focusing on feasibility, osseointegration, and patient outcomes. METHODS: This retrospective study involved seven patients who received 3D-printed personalized lattice implants for the reconstruction of geographic defects in load-bearing bones. Personalized implants were customized for each patient. Randomized dodecahedron unit cells were incorporated within the implants to create the porous structure. The pore size and porosity were analyzed. Patient outcomes were assessed through a combination of clinical and radiological evaluations. Tomosynthesis-Shimadzu metal artifact reduction technology (T-SMART) was utilized to evaluate osseointegration. Functional outcomes were assessed according to the Musculoskeletal Tumor Society (MSTS) 93 score. RESULTS: Multiple pore sizes were observed in porous structures of the implant, with a wide distribution range (approximately 300-900 um). The porosity analysis results showed that the average porosity of irregular porous structures was around 75.03%. The average follow-up time was 38.4 months, ranging from 25 to 50 months. Postoperative X-rays showed that the implants matched the geographic bone defect well. Osseointegration assessments according to T-SMART images indicated a high degree of bone-to-implant contact, along with favorable bone density around the implants. Patient outcomes assessments revealed significant improvements in functional outcomes, with the average MSTS score of 27.3 (range, 26-29). There was no implant-related complication, such as aseptic loosening or structure failure. CONCLUSION: 3D-printed personalized lattice implants offer an innovative and promising strategy for geographic defect reconstruction in load-bearing bones. This approach has the potential to match the unique contours and geometry of the geographic bone defect and facilitate osteointegration.

Pay Attention to the Osteochondromas in Fibrodysplasia Ossificans Progressiva.

BACKGROUND: Fibrodysplasia ossificans progressiva (FOP) is an extremely rare disease characterized by malformation of the bilateral great toes and progressive heterotopic ossification. The clinical features of FOP occur due to dysfunction of the bone morphogenetic protein (BMP) signaling pathway induced by the mutant activin A type I receptor/activin-like kinase-2 (ACVR1/ALK2) which contributes to the clinical features in FOP. Dysregulation of the BMP signaling pathway causes the development of osteochondroma. Poor awareness of the association between FOP and osteochondromas always results in misdiagnosis and unnecessary invasive operation. CASE PRESENTATION: In this study, we present a case of classical FOP involving osteochondroma. An 18-year-old male adolescent, born with deformity of bilateral big toes, complained multiple masses on his back for 1 year. The mass initially emerged with a tough texture and did not cause pain. It was misdiagnosed as an osteochondroma. After two surgeries, the masses became hard and spread around the entire back region. Meanwhile, extensive heterotopic ossification was observed around the back, neck, hip, knee, ribs, and mandible during follow-up. Osteochondromas were observed around the bilateral knees. No abnormalities were observed in the laboratory blood test results. Whole exome sequencing revealed missense mutation of ACVR1/ALK2 (c.617G > A; p.R206H) in the patient and confirmed the diagnosis of FOP. CONCLUSION: In summary, classical FOP always behaves as a bilateral deformity of the big toes, as well as progressive ectopic ossification and osteochondromas in the distal femur and proximal tibia. An understanding of the association between osteochondromas and FOP aids in diagnosis and avoids unnecessary invasive management in patients.

Reconstruction of the proximal radius with 3D-printed personalized prosthesis after tumor resection: case series.

BACKGROUND: Giant cell tumor of bone (GCTB) (Campanacci III) or malignant tumors extend to the epiphyseal region of the proximal radius, and intra-articular resection of the proximal radius is often needed. In the present study, we present the patients who underwent reconstruction of the proximal radius with 3D-printed personalized prosthesis after tumor resection, aiming to describe the prosthesis design and surgical technique and evaluate the clinical outcomes of this method. METHODS: Between November 2018 and January 2021, 9 patients received radial hemiarthroplasty with 3D-printed personalized prostheses after tumor resection. The pathologic diagnosis was GCTB (Campanacci III) in 7 patients, osteosarcoma (IIB) in 1 patient, and synovial sarcoma (IIB) in 1 patient. The range of motion (ROM) and strength in terms of elbow flexion/extension and forearm supination/pronation were evaluated. Pain was assessed by the visual analog scale (VAS) preoperatively and at each follow-up visit. To evaluate the functional outcome, the Mayo Elbow Performance Score (MEPS) system and the Musculoskeletal Tumor Society (MSTS) scoring system were administered at each follow-up visit. Complications and oncological outcomes were recorded. RESULTS: The patients were followed from 24 to 51 months, with a median follow-up of 35 months. No patients were lost to follow-up. During the follow-up, local recurrence and metastasis were not observed. The VAS score improved from a median of 5 points (range 4-7) preoperatively to 1 point (range 0-2) at the last follow-up visit. The mean MEPS score was 88.5% (83-93), and the mean MSTS score was 25.3 (24-27) at the last follow-up visit. No complications such as infection and aseptic loosening were detected. CONCLUSIONS: The implantation of a 3D-printed personalized prosthesis after proximal radial resection showed excellent oncologic outcomes and postoperative function at short-term follow-up and is a viable alternative method for reconstruction of the proximal radius bone defect after tumor resection.

Intercalary Prosthetic Reconstruction with Three-Dimensional-Printed Custom-Made Porous Component for Defects of Long Bones with Short Residual Bone Segments After Tumor Resection.

BACKGROUND: Intercalary reconstruction for patients with short residual bone segments remains challenging. Three-dimensional (3D)-printed custom-made porous implants are a promising technique for short-segment fixation in these patients. This study aims to evaluate the efficiency of 3D-printed custom-made porous components (3DCPCs) for short-segment fixation, focusing on prosthesis survivorship, radiographic results, and potential complications. METHODS: This retrospective study involved 39 patients who underwent intercalary prosthetic reconstruction with 3DCPCs after tumor resection of the femur, tibia, or humerus from June 2015 to October 2020. Segment bone loss involved the femur (n = 15), tibia (n = 16), and humerus (n = 8), leaving 78 residual bone segments. There were 46 short segments requiring 46 3DCPCs and 32 segments with the ability to accommodate 32 off-the-shelf standard uncemented stems for prosthesis fixation. Clinical and functional outcomes were evaluated. Prosthesis-overall survivorship and prosthesis-specific survivorship were analyzed using Kaplan-Meier survival analysis. Radiographic results and modes of failure of using this technique were also examined. RESULTS: The mean follow-up was 41 months. The prosthesis-overall survivorship was 87.2% and 84.6% at 2 and 5 years, respectively. The prosthesis-specific survivorship was 92.1% and 89.5% at 2 and 5 years, respectively. There was not a substantial difference in prosthesis survivorship among the femur, tibia, and humerus. The average MSTS score was 26.2, ranging from 22 to 28. The radiographic evaluation results revealed excellent or good interface (38/46) in most of the 46 porous components. A total of 38 of 46 bone segments' remolding demonstrated no change. In total, seven patients (16.3%) had complications requiring further surgery. CONCLUSION: The prosthesis survivorship of using 3DCPCs for short-segment fixation is similar or better compared to other studies involving intercalary prosthetic reconstruction with short-segment fixation. Radiographic evaluation revealed good osteointegration and avoidance of stress shielding. Overall, intercalary prosthetic reconstruction with 3DCPC is a feasible modality for patients with short residual bone segments after tumor resection.

The combination of baseline neutrophil to lymphocyte ratio and dynamic changes during treatment can better predict the survival of osteosarcoma patients.

Background: Osteosarcoma is a primary malignant bone tumor with a high metastatic potential that accounts for a significant proportion of all bone tumors. The prognosis for patients with metastatic or recurrence disease remains poor. The neutrophil-to-lymphocyte ratio (NLR) has become a potential prognostic biomarker for cancer. Recent evidence suggests that the dynamic changes in neutrophil-to-lymphocyte ratio (NLR) during treatment may be more informative in predicting patient prognosis, but the value of dynamic NLR in osteosarcoma has not yet been determined. Methods: This retrospective study retrospectively analyzed the clinical information of 251 osteosarcoma patients diagnosed and treated in West China Hospital of Sichuan University, explored the impact of baseline NLR and changes in NLR during treatment on the prognosis of osteosarcoma patients, and further combined baseline NLR with Delta NLR to build an NLR staging system. Results: The results showed that both baseline NLR and delta NLR had some predictive ability for the prognosis of osteosarcoma patients (P = 6.90e-4, P = 0.022). Patients with high baseline NLR were more likely to have a decrease in delta NLR (P = 1.24e-10). The NLR stage had a better predictive ability than baseline NLR and delta NLR, and was an independent prognostic factor for overall survival in osteosarcoma patients HR: 2.456 (1.625-3.710) (P = 1.97e-05). Conclusion: NLR has value in continuous monitoring, and continuous monitoring of NLR can better predict the survival of osteosarcoma patients compared to baseline NLR.

[Three-dimensional-printed hemi-pelvic prosthesis for revision of aseptic loosening or screw fracture of modular hemi-pelvic prosthesis].

Objective: To investigate the effectiveness of three-dimensional (3D)-printed hemi-pelvic prosthesis for revision of aseptic loosening or screw fracture of modular hemi-pelvic prosthesis. Methods: Between February 2017 and January 2020, 11 patients with aseptic loosening or screw fracture of modular hemi-pelvic prosthesis were revised using 3D-printed hemi-pelvic prostheses. There were 7 males and 4 females with an average age of 44 years (range, 25-60 years). In the first operation, all patients underwent total tumor resection, modular hemi-pelvic prosthesis reconstruction, and autologous femoral head transplantation. According to the Enneking pelvic partition system, 8 cases were resected in zones Ⅰ+Ⅱ and 3 cases in zones Ⅰ+Ⅱ+Ⅲ. The interval from the initial operation to this revision ranged from 14.3-66.2 months, with an average of 35.8 months. The operation time, the amount of intraoperative bleeding, and the occurrence of complications were recorded. At 6 months after the first operation, before revision, and at last follow-up, the American Musculoskeletal Tumor Society (MSTS) score and Harris score were used to evaluate the recovery of lower limb function. The pain-free walking distance of patients without brace assistance was recorded at last follow-up. X-ray films were taken at 1 month after the first operation, before revision, and at 1 month after revision, the acetabulum position was assessed by the differences in weight arm and cup height between bilateral hip joints. At last follow-up, the digital X-ray tomography was taken to evaluate the prosthesis-bone integration and the occurrence of aseptic loosening. Results: The operation time was 182.6-238.0 minutes (mean, 197.4 minutes). The amount of intraoperative bleeding was 400-860 mL (mean, 550.0 mL). All incisions healed by first intention with no infection, hip dislocation, nerve damage, or vascular-related adverse events. The MSTS score and Harris score at last follow-up were significantly higher than those at 6 months after the first operation and before revision ( P<0.05), while the score before revision was significantly lower than that at 6 months after the first operation ( P<0.05). At last follow-up, the patients were able to walk more than 1 000 meters painlessly without brace assistance. Imaging review showed that the difference of cup height at 1 month after revision was significantly lower than that at 1 month after the first operation and before revision, and at 1 month after the first operation than before revision operation, and the differences were significant ( P<0.05). There was no significant difference in the difference of weight arm among three time points ( P>0.05). All prostheses were well integrated, and no aseptic loosening of the prosthesis or screw fracture occurred. Conclusion: Revision with 3D-printed hemi-pelvic prostheses benefited in reconstructing stable pelvic ring and natural bodyweight transmission for patients encountering the aseptic loosening or screw fracture of modular hemi-pelvic prosthesis. Early postoperative rehabilitation training can maximize the recovery of patient limb function, reduce pain during walking, and reduce the incidence of complications.

[Long-term effectiveness of uncemented allograft-prosthesis composite for reconstruction of bone defects after proximal femur tumor resection].

Objective: To investigate the long-term effectiveness of uncemented allograft-prosthesis composite (APC) for reconstruction of bone defects after proximal femur tumor resection. Methods: Between June 2007 and March 2014, 21 patients who underwent uncemented APC reconstruction of proximal femur after tumor resection were retrospectively evaluated. There were 9 males and 12 females with an average age of 33.2 years (range, 19-54 years). There were 9 cases of giant cell tumor of bone, 5 cases of osteosarcoma, 4 cases of osteoblastic osteosarcoma, 2 cases of chondrosarcoma, and 1 case of undifferentiated pleomorphic sarcoma. Thirteen cases of benign bone tumors were all classified as stage 3 by Enneking staging; and 8 cases of malignant bone tumors were classified as grade ⅡB in 7 cases and grade ⅡA in 1 case according to the American Joint Committee on Cancer (AJCC) staging system. Among them, 7 patients underwent reoperation after recurrence, and the rest were primary operations; 8 patients presented with pathological fractures. The preoperative Harris hip score (HHS) and American Musculoskeletal Tumor Society (MSTS) score was 40 (30, 49) and 9.1±3.5, respectively. The length of osteotomy was 80-154 mm, with an average of 110 mm. At 1 year after operation and last follow-up, HHS and MSTS scores were utilized to evaluate the function of hip joint; the gluteus medius strength score was used to evaluation of the hip abduction function. Image examinations were taken at 1, 3, 6, 9, and 12 months after operation and every year thereafter to assess the union of allograft-host bone interfaces. Intra- and post-operative complications were also recorded. Results: All patients were followed up 84-163 months (mean, 123.5 months). At 1 year after operation and last follow-up, the HHS and MSTS scores significantly improved when compared with the preoperative scores ( P<0.05). However, there was no significant difference in the HHS score, MSTS score, and gluteus medius strength score between the two time points after operation ( P>0.05). Image examination showed that all allograft-host bone interfaces achieved union after 5-10 months (mean, 7.6 months). At last follow-up, all patients had bone resorption, including 11 severe cases, 4 moderate cases, and 6 mild cases; the bone resorption sites included Gruen 1, 2, and 7 regions. Complications included 10 fractures and 1 prosthetic fracture. Local recurrence occurred in 3 patients and pulmonary metastasis in 3 patients. Conclusion: Uncemented APC is a reliable method for the reconstruction of bone defects after proximal femur tumor resection. It has the good long-term effectiveness and possesses obvious advantages in the union at the bone-bone surface.

Pelvic-girdle reconstruction with three-dimensional-printed endoprostheses after limb-salvage surgery for pelvic sarcomas: current landscape.

Resection of pelvic bone tumors and the subsequent reconstruction of the pelvic girdle pose challenges due to complex anatomy, load-bearing demands, and significant defects. 3D-printed implants have revolutionized pelvic girdle reconstruction by offering customized solutions, porous surface structures for precise resection with custom guides, and improved integration. Many tertiary medical centers have adopted 3Dprinted hemipelvic endoprostheses, leading to enhanced outcomes. However, most studies are limited to single centers, with a small number of cases and short follow-up periods. Additionally, the design of these implants often relies heavily on individual experience, resulting in a lack of uniformity and significant variation. To provide a comprehensive assessment of this technology, we conducted an analysis of existing literature, encompassing tumor resection classification, various types of prosthesis design, reconstruction concepts, and post-reconstruction functional outcomes.

Clinical evaluation of the three-dimensional printed strut-type prosthesis combined with autograft reconstruction for giant cell tumor of the distal femur.

Propose: This study aimed to describe the design and surgical techniques of a three-dimensional (3D) printed strut-type prosthesis with a porous titanium surface for distal femur giant cell tumors of bone (GCTB) and evaluate the short-term clinical outcomes. Methods: From June 2018 to January 2021, 9 consecutive patients with grade I or II GCTB in the distal femur underwent extended intralesional curettage followed by 3D-printed strut-type prosthesis combined with autograft reconstruction were retrospectively reviewed to assess their clinical and radiographic outcomes. Results: All patients were followed up for 30.8 ± 7.5 months (18-42 months) after surgery. The mean affected subchondral bone percentage and the mean subchondral bone thickness before surgery was 31.8% ± 9.6% (range, 18.2% ~50.2%) and 2.2 ± 0.8 mm (range, 1.2-4.0 mm), respectively. At the final follow-up, all the patients were alive without local recurrence; no postoperative complications were observed. Patients had significant improvements in postoperative MSTS-93 score [(26.7 ± 2.4) vs. (18.8 ± 3.7), P < 0.05], and ROM [(122.8° ± 9.1°) vs. (108.3° ± 6.1°), P < 0.05] compared with their preoperative statuses. Furthermore, the mean subchondral bone thickness has increased to 10.9 ± 1.3 mm (range, 9.1-12.1 mm). Conclusion: 3D-printed strut-type prosthesis combined with autograft reconstruction provides acceptable early functional and radiographic outcomes in patients with grade I or II GCTB in distal femur due to the advantages of the prosthesis such as good biocompatibility, osseointegration capacity, and subchondral bone protection. If our early outcomes can be further validated in studies with more patients and sufficient follow-up, this method may be evaluated as an alternative for the treatment of grade I or II GCTB in the distal femur.

Computer-aided Design and 3D-printed Personalized Stem-plate Composite for Precision Revision of the Proximal Humerus Endoprosthetic Replacement: A Technique Note.

BACKGROUND: Aseptic loosening is considered to be a rather uncommon complication in proximal humerus endoprosthetic replacement (PHER). However, patients with aseptic loosening often suffer severe bone loss, which poses a great challenge in following revision. Under this situation, a standard stemmed endoprosthesis is unavailable for revision limb salvage. Computer-aided design and 3D-printed personalized implants are an emerging solution for reconstructing complex bone defects. CASE PRESENTATION: Here, we present a 67-year-old male who underwent PHER after tumor resection and developed aseptic loosening with severe periprosthetic osteolysis around the stem. Computer-aided design and 3D-printed personalized stem-plate composite was used for the precision revision of this patient. During the follow-up, encouraging results were observed, with good endoprosthetic stability and satisfactory limb function. CONCLUSION: Computer-aid design and 3D-printed personalized stem-plate composite used in the present case could help to achieve good endoprosthetic stability and satisfactory limb function. This 3D-printed personalized stem-plate composite seems to be an effective method for the precise revision of PHER in patients with severe periprosthetic osteolysis. In addition, it also provides a novel method for similar revision surgery of other joints or primary endoprosthetic replacement with severe bone defects.

Treatment of pelvic giant cell tumor by wide resection with patient-specific bone-cutting guide and reconstruction with 3D-printed personalized implant.

BACKGROUND: This study reports our experience in the treatment of aggressive pelvic GCT through wide resection assisted with patient-specific bone-cutting guides (PSBCGs) and subsequent reconstruction with 3D-printed personalized implants (3DPIs), aiming to present the operative technique of this method and evaluate its clinical efficacy. METHODS: We retrospectively analyzed seven patients who underwent wide resection of pelvic GCT followed by reconstruction with 3DPIs from August 2019 to February 2021. There were two males and five females, with a mean age of 43 years. PSBCGs and 3DPIs were prepared using 3D-printing technology. The operational outcomes, local recurrence, radiological results, and any associated complications of this technique were assessed. And the functional outcomes were assessed according to the Musculoskeletal Tumor Society (MSTS) 93 functional score. RESULTS: The mean follow-up time was 35.3 months (range 28-45 months). There was no intraoperative complication. Negative surgical margins were achieved in all patients. Postoperative pelvic radiographs showed that 3DPIs matched the shape and size of the bone defect. The anterior-posterior, inlet, and outlet pelvic radiograph demonstrated precise reconstruction consistent with the surgical planning. In addition, tomosynthesis-Shimadzu metal artifact reduction technology (T-SMART) showed good osseointegration at an average of three months after surgery (range 2-4 months). There was no local recurrence or tumor metastasis. The average MSTS score was 24.4 (range 23-27) at the last follow-up. Delayed wound healing was observed in one patient, and the wounds healed after debridement. Prosthesis-related complications were not detected during the follow-up, such as aseptic loosening or structure failure. CONCLUSIONS: The treatment of aggressive pelvic GCTs through wide resection assisted with PSBCGs and subsequent reconstruction with 3DPIs is a feasible method, which provides good clinical results and reasonable functional outcomes.