Comparison of Porous Tantalum Acetabular Implants and Harrington Reconstruction for Metastatic Disease of the Acetabulum

Safety and efficacy of combined acetabular reconstruction and microwave ablation in the treatment of periacetabular metastatic disease: a retrospective clinical evaluation

Introduction

The periacetabular bone defects caused by metastatic disease often necessitate acetabular reconstruction and various techniques have been employed with varying degrees of success. The purpose of this study was to evaluate the efficacy and safety of acetabular reconstruction in conjunction with adjuvant microwave ablation as a surgical intervention for patients with periacetabular metastases.

Methods

Between January 2019 and September 2023, 17 consecutive patients with different tumor subtypes required surgical intervention for periacetabular metastases. The acetabular reconstruction was performed by utilizing an acetabular reconstructive cage and cement total hip arthroplasty with microwave ablation. A retrospective review was performed to assess pain relief, intraoperative details and postoperative complications. Functional status following procedures was determined by the 1993 Musculoskeletal Tumor Society (MSTS) score and the overall survival of patients was estimated by Kaplan-Meier analysis.

Results

In total, 8 males and 9 females were included with an average age of 48.6 years (range 34-66). Patients reported a significant improvement in the level of pain and the mean VAS score declined from 7.7 preoperatively to 2.2 postoperatively. Of the 17 patients, 16 could ambulate either independently (6 patients) or using a walking aid (10 patients) with a mean MSTS score of 18.9. The median follow-up was 9.0 months. Nine patients were alive at the most recent follow-up with overall survival of 40.9% at 12 months and 30.7% at 36 months, respectively.

Conclusion

In selected patients with periacetabular metastasis, the utilization of an acetabular cage and cement total hip arthroplasty presents a less invasive reconstruction technique. The incorporation of adjuvant microwave ablation has shown promise in providing long-lasting pain relief, reducing intraoperative bleeding, and improving local tumor control. However, further research and extended follow-up are necessary to establish the effectiveness of this procedure.

Management of metastatic bone disease of the pelvis: current concepts

PURPOSE

Metastatic disease of the pelvis is frequently associated with severe pain and impaired ambulatory function. Depending on the patient's characteristics, primary tumor, and metastatic pelvic disease, the treatment choice may be varied. This study aims to report on the current management options of metastatic pelvic disease.

METHODS

We comprehensively researched multiple databases and evaluated essential studies about current concepts of managing a metastatic bone disease of the pelvis, focusing on specific indications as well as on the result of treatment.

RESULTS

Pelvic metastases not in the periacetabular region can be managed with modification of weight-bearing, analgesics, bisphosphonates, chemotherapy and/or radiotherapy. Minimally invasive approaches include radiofrequency ablation, cryoablation, embolization, percutaneous osteoplasty, and percutaneous screw placement. Pathological or impending periacetabular fracture, excessive periacetabular bone defect, radioresistant tumor, and persistent debilitating pain despite non-surgical treatment and/or minimally invasive procedures can be managed with different surgical techniques. Overall, treatment can be divided into nonoperative, minimally invasive, and operative based on specific indications, the expectations of the patient and the lesion.

CONCLUSION

Different treatment modalities exist to manage metastatic pelvic bone disease. Decision-making for the most appropriate treatment should be made with a multidisciplinary approach based on a case-by-case basis.

Artificial intelligence assisted preoperative planning and 3D-printing guiding frame for percutaneous screw reconstruction in periacetabular metastatic cancer patients

Background

The percutaneous screw reconstruction technique, known as the "Tripod Technique," has demonstrated favorable clinical outcomes in the management of metastatic periacetabular lesions, as evidenced by our prior investigations and corroborated by independent studies. Nevertheless, there is a steep learning curve in handling this technique, with possible complications such as intraarticular screw placement.

Methods

Preoperative pelvic CT scans were acquired before surgery and utilized for the guiding frame design. A convolutional neural network model was trained with annotated data to identify the starting point and trajectory of each potential screw. A model boundary intersection detection technology was used to determine the optimal diameter and length of each screw. A non-rigid registration technology was matched with a prefabricated model of the body surface to design personalized anchoring skin pads. Finally, a polylactic acid-based guiding frame for intraoperative was custom-made with a 3D printer.

Results

12 patients underwent a guiding frame-assisted Tripod procedure for treatment of periacetabular metastatic lesions. An intraoperative CT scan was performed in all cases to confirm screw trajectories. Among 36 screws that were implanted, 26 screws were implanted as designed. The remaining ten screws drifted, but all remained within the intra-osseous conduit without any complications. The mean surgical time was 1.22 h with the guiding frame compared with 2.3 h without the guiding frame. Following the surgical procedure, a noteworthy enhancement in pain management, as evidenced by a reduction in scores on the visual analog scale (p < 0.01), and an improvement in functional status, as assessed through the Eastern Cooperative Oncology Group score (p < 0.01), were observed when compared to the patient's pre-operative condition.

Conclusion

This proof-of-concept investigation demonstrates that the amalgamation of AI-assisted surgical planning and additive manufacturing can improve surgical accuracy and shorten surgical duration. While access to this technology is currently constrained during its early stages of development, it is anticipated that these limitations will diminish as the potential of AI and additive manufacturing in facilitating complex orthopedic procedures becomes more evident, leading to a surge in interest and adoption of this approach.

Assessing Pain and Functional Outcomes of Percutaneous Stabilization of Metastatic Pelvic Lesions via Photodynamic Nails: A Bi-Institutional Investigation of Orthopaedic Outcomes

Background

Minimally invasive surgical interventions for metastatic invasion of the pelvis have become more prevalent and varied. Our group hypothesized that the use of percutaneous photodynamic nails (PDNs) would result in decreased pain, improved functional outcomes and level of ambulation, and decreased use of opioid pain medication.

Methods

We performed a retrospective chart review of patients with metastatic pelvic bone disease undergoing stabilization with PDNs (IlluminOss Medical) at 2 institutions. Functional outcome measures assessed include the Combined Pain and Ambulatory Function (CPAF), Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function, and PROMIS Global Health-Physical. Pain was assessed using a visual analog scale (VAS). Outcomes were assessed preoperatively and at 6 weeks, 3 months, 6 months, and 1 year following surgery.

Results

A total of 39 patients treated with PDNs were included. No cases of surgical site infection or implant failure were identified. The median pain VAS score decreased from 8 preoperatively to 0 at the 6-week time point (p < 0.0001). The median CPAF score improved from 5.5 points preoperatively to 7 points at the 3-month mark (p = 0.0132). A significant improvement in physical function was seen at 6 months in the PROMIS Physical Function (p = 0.02) and at both 6 months (p = 0.01) and 1 year (p < 0.01) for the PROMIS Global Health-Physical. The rate of patients prescribed opioid analgesia dropped from 100% preoperatively to 20% at 6 months following surgery (p < 0.001). By 6 weeks, all patients were fully weight-bearing and able to walk independently with or without assistive devices.

Conclusions

Percutaneous stabilization of metastatic periacetabular defects using PDNs is a safe and effective palliative procedure that has been shown to improve patient mobility and provide early pain relief.

Level of Evidence

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Modified Harrington Procedure for Metastatic Peri-Acetabular Bone Lesion Using a Novel Highly Porous Titanium Revision Shell with Long Lever Arm Screw

Background and Objectives: Peri-acetabular metastases often lead to significant pain and functional impairment. Surgical interventions, including the Harrington procedure, aim to address these challenges. This study evaluates a modified Harrington procedure using the MUTARS® PRS® (Pelvic Revision Shell) with an 8 mm fixation screw for severe acetabular defects resulting from metastatic lesions. Materials and Methods: Retrospective analysis of 12 patients treated between January 2020 and December 2023 was conducted. The procedure involved using the novel MUTARS® PRS® with an 8 mm in diameter dome screw (length 70-100 mm). Outcome measures included implant positioning changes, complication rates, functional outcomes, implant longevity, and patient survival. Radiological assessments were performed postoperatively, with follow-ups at 3, 6, 12 months, and annually thereafter. Results: Average follow-up was 15 ± 11 months, with 67% patient survival at 1 year and 44% at 2 years. Implant survivorship remained 100%. Harris Hip Score improved significantly from 37 ± 22 preoperatively to 75 ± 15 at the last follow-up. No revisions involving implant components were reported. Complications occurred in 5 of 12 patients. Overall, PRS® demonstrates effective osseous ingrowth, high primary stability, immediate full weight-bearing, and low complication rates. Conclusions: PRS® integrates facilitating osseous ingrowth for preferable long-term outcomes, while efficiently transmitting the weight-bearing load to the intact aspect of the pelvis using a long 8 mm lever screw, enhancing the primary stability of the construct. It proves to be an effective and reproducible technique for managing destructive metastatic lesions of the acetabulum and peri-acetabular region, even in irradiated bone.

Progress of research on the surface functionalization of tantalum and porous tantalum in bone tissue engineering

Tantalum and porous tantalum are ideal materials for making orthopedic implants due to their stable chemical properties and excellent biocompatibility. However, their utilization is still affected by loosening, infection, and peripheral inflammatory reactions, which sometimes ultimately lead to implant removal. An ideal bone implant should have exceptional biological activity, which can improve the surrounding biological microenvironment to enhance bone repair. Recent advances in surface functionalization have produced various strategies for developing compatibility between either of the two materials and their respective microenvironments. This review provides a systematic overview of state-of-the-art strategies for conferring biological functions to tantalum and porous tantalum implants. Furthermore, the review describes methods for preparing active surfaces and different bioactive substances that are used, summarizing their functions. Finally, this review discusses current challenges in the development of optimal bone implant materials.

Trabecular Metal Augments During Complex Primary Total Hip Arthroplasty

Background

Trabecular metal augments (TMAs) have been extensively used in revision total hip arthroplasty (THA) to address acetabular bone defects. However, limited data exists regarding TMA utilization during primary THA. This study aims to assess the clinical and radiographic outcomes of TMAs used during primary THA.

Methods

A single-institution retrospective case series of primary THA patients treated with TMA between 2010 and 2019 was performed. Patient demographics, complications, and revisions were recorded. Cup position, center of rotation, leg length, and radiolucent lines were assessed radiographically. The Kaplan-Meier method was used to compute implant survivorship.

Results

Twenty-six patients (30 hips) were included with average age of 52.6 ± 15.3 years (range: 22-78) and mean follow-up of 4.1 ± 2.1 years (range: 2.0-8.9). Most TMAs were indicated for developmental dysplasia of the hip (n = 18; 60.0%). On average, hip center of rotation was lowered 1.5 ± 1.3 cm and lateralized 1.2 ± 1.5 cm, while leg length and global offset were increased by 2.4 ± 1.2 cm and 0.4 ± 1.0 cm, respectively. At final follow-up, 3 hips (10.0%) required revision: one (3.3%) for aseptic loosening and 2 (6.7%) for instability. No patients had progressive radiolucent lines at final follow-up. Five-year survival with aseptic loosening and all-cause revision as endpoints was 100% (95% confidence interval: 90.0%-100.0%) and 92.1% (95% confidence interval: 81.3%-100.0%), respectively. One patient required revision for aseptic loosening after the 5-year mark.

Conclusions

Trabecular metal augmentation during primary THA demonstrates satisfactory early to mid-term outcomes. TMA is a viable option for complex primary THA when bone loss is encountered or secondary support is required.

Level of Evidence

Level IV.

Preparation, biological activity and antibacterial properties of tantalum surface-doped Ca2+/Zn2+nanorods

In this research, we utilize porous tantalum, known for its outstanding elastic modulus and biological properties, as a base material in biomedical applications. The human skeletal system is rich in elements like Ca and Zn. The role of Zn is crucial for achieving a spectrum of sterilizing effects, while Ca is known to effectively enhance cell differentiation and boost cellular activity. The focus of this study is the modification of porous tantalum using a hydrothermal method to synthesize Ca2+/Zn2+-doped Ta2O5nanorods. These nanorods are subjected to extensive characterization techniques to confirm their structure and composition. Additionally, their biological performance is evaluated through a range of tests, including antibacterial assessments, MTT assays, and bacteria/cell scanning electron microscopy (SEM) analyses. The objective is to determine the most effective method of surface modification for porous tantalum, thereby laying a foundational theoretical framework for its surface enhancement.

Hip Reconstruction In Situ with Screws and Cement (HiRISC) construct to treat large acetabular bone defects

Aims

Large bone defects resulting from osteolysis, fractures, osteomyelitis, or metastases pose significant challenges in acetabular reconstruction for total hip arthroplasty. This study aimed to evaluate the survival and radiological outcomes of an acetabular reconstruction technique in patients at high risk of reconstruction failure (i.e. periprosthetic joint infection (PJI), poor bone stock, immunosuppressed patients), referred to as Hip Reconstruction In Situ with Screws and Cement (HiRISC). This involves a polyethylene liner embedded in cement-filled bone defects reinforced with screws and/or plates for enhanced fixation.

Methods

A retrospective chart review of 59 consecutive acetabular reconstructions was performed by four surgeons in a single institution from 18 October 2018 to 5 January 2023. Cases were classified based on the Paprosky classification, excluding type 1 cases (n = 26) and including types 2 or 3 for analysis (n = 33). Radiological loosening was evaluated by an orthopaedic surgeon who was not the operating surgeon, by comparing the immediate postoperative radiographs with the ones at latest follow-up. Mean follow-up was 557 days (SD 441; 31 to 1,707).

Results

Out of the 33 cases analyzed, six (18.2%) constructs required revision, with four revisions due to uncontrolled infection, one for dislocation, and one for aseptic loosening. Among the 27 non-revised constructs, only one showed wider radiolucencies compared to immediate postoperative radiographs, indicating potential loosening. Patients who underwent revision (n = 6) were significantly younger and had a higher BMI compared to those with non-revised constructs (p = 0.016 and p = 0.026, respectively). Sex, race, ethnicity, American Society of Anesthesiologists grade, infection status (patients with postoperative PJI diagnosis (septic) vs patients without such diagnosis (aseptic)), and mean follow-up did not significantly differ between revised and non-revised groups.

Conclusion

The HiRISC technique may serve as a feasible short-term (about one to two years) alternative in patients with large acetabular defects, particularly in cases of PJI. Longer follow-up is necessary to establish the long-term survival of this technique.

Recent Advances in Minimally Invasive Management of Osteolytic Periacetabular Skeletal Metastases

Painful skeletal osteolytic metastases, impending pathological fractures, and nondisplaced fractures present as a devastating clinical problem in advanced stage cancer patients. Open surgical approaches provide excellent mechanical stabilization but are often associated with high complication rates and slow recovery times. Percutaneous minimally invasive interventions have arisen as a pragmatic and logical treatment option for patients with late-stage cancer in whom open surgery may be contraindicated. These percutaneous interventions minimize soft tissue dissection, allow for the immediate initiation or resumption of chemotherapies, and present with fewer complications. This review provides the most up-to-date technical and conceptual framework for the minimally invasive management of osseous metastases with particular focus on periacetabular lesions. Fundamental topics discussed are as follows: (1) pathogenesis of cancer-induced bone loss and the importance of local cytoreduction to restore bone quality, (2) anatomy and biomechanics of the acetabulum as a weight-bearing zone, (3) overview of ablation options and cement/screw techniques, and (4) combinatorial approaches. Future studies should include additional studies with more long-term follow-up to better assess mechanical durability of minimally invasive interventions. An acetabulum-specific functional and pain scoring framework should be adopted to allow for better cross-study comparison.

Does Perioperative Radiation Affect Implant Survivorship of Primary Total Hip Arthroplasty in the Setting of Metastatic Bone Disease?

Background

Metastatic bone disease (MBD) commonly affects the hip and surgical intervention including total hip arthroplasty (THA) is often indicated to treat the joint and improve function. Patients with metastatic cancer often receive radiotherapy, and orthopaedic oncologists must consider surgical risks with operating on irradiated bone and soft tissue. We evaluated surgical outcomes and implant survival (IS) of titanium acetabular components and femoral components in patients treated for MBD in the setting of perioperative radiation.

Methods

This was a retrospective review of patients who underwent THA for MBD at 3 institutions between 2017 and 2021. Outcomes included rates of reoperation, complications, IS, and overall survival.

Results

Forty-six patients who received primary THA for MBD were included in the study. Twenty patients (43.5%) received perioperative radiation for MBD. Six postoperative complications including one superficial wound infection, 2 dislocations, 2 pathologic fractures, and one aseptic acetabular component loosening led to 5 reoperations. There were no significant differences in postoperative outcomes, reoperation after THA, and IS based on radiotherapy status.

Conclusions

To our knowledge, this is the first paper evaluating primary THA outcomes and IS between patients who receive perioperative radiation for MBD to the hip and those who do not. As surgical management is a crucial part of the treatment in alleviating pain and disability in patients with MBD, we continue to recommend THA for patients who received radiation at the operative site.

Functional outcomes after open reconstruction or nonoperative management of 81 pathologic acetabular fractures from metastatic bone disease

Background

Pathologic acetabular fracture secondary to skeletal metastasis may result in debilitating pain, inability to ambulate, and impaired quality of life, which may mark the first period of dependent care in cancer patients. Acetabular reconstruction may involve morbid procedures with increased complication rates. This study aimed to evaluate the evolution of pain, performance status, and ambulation following nonoperative management or open reconstruction of pathologic acetabular fractures.

Methods

A retrospective cohort of 2630 adult patients with osseous metastatic disease treated at a high-volume cancer center between 2005 and 2021 was screened for pathologic fractures of the acetabulum. The study outcomes were pain, performance status, and the ability to ambulate. We identified 78 patients (median age, 60 years; 37 female patients [46%]) with 81 fractures. Of these, treatment consisted of open reconstruction (n = 34) or nonoperative management alone (n = 47). The mean follow-up in surviving patients was 3.4 years.

Results

Open reconstruction was performed more frequently for displaced fractures (P < 0.01), Harrington class III or IV acetabula (P < 0.01), and patients with a performance status ≥3 at hospitalization (P = 0.00). Open reconstruction was associated with clinically meaningful improvements in pain (adjusted odds ratio [aOR], 8.3; 95% CI, 1.4-50.6; P = 0.02) and performance status (aOR, 10.9; 95% CI, 1.7-71.0; P = 0.01) at discharge and a restoration of ambulation (aOR, 7.5; 95% CI, 1.9-29.8; P < 0.01) at final follow-up.

Conclusions

In patients with pathologic acetabular fracture due to osseous metastatic disease, functional improvements in pain, performance status, and ambulation were observed following open acetabular reconstruction in carefully selected patients, with no impact on survival, while noninferior improvements were observed in patients receiving nonoperative management when considering their larger clinical context.

Level of evidence

Level III, therapeutic study.

Improving osteoinduction and osteogenesis of Ti6Al4V alloy porous scaffold by regulating the pore structure

Titanium alloy scaffolds with a porous structure have attracted much attention in bone defect repair. However, which pore structure is more beneficial to bone defect repair is controversial. In the present research, the Ti6Al4V alloy porous scaffolds with gradient pore sizes were designed and fabricated. The microstructure characterization, tests of mechanical properties, and in vitro and in vivo experiments have been performed to systematically evaluate the effect of pore size on osteoinduction and osteogenesis. The results revealed that the contact angle with water, compressive strength, and elastic modulus of the Ti6Al4V alloy porous scaffolds decreased gradually with the increase of pore size. However, there were obvious drops when the pore size of the porous scaffold was around 600 μm. As the pore size increased, the proliferation and integrin β1 of RAW 264.7 macrophages seeded on Ti6Al4V alloy porous scaffolds increased at first, reaching a maximum value at a pore size of around 600 μm, and then decreased subsequently. The proliferation, integrin β1, and osteogenic gene-related expressions of Bone marrow mesenchymal stem cells (BMSCs) seeded on Ti6Al4V alloy porous scaffolds with different pore sizes all exhibited similar variations which rose with increased pore size firstly, obtaining the maximum value at pore size about 600 μm, and then declined. The in vivo experiments confirmed the in vitro results, and the Ti6Al4V alloy porous scaffold with a pore size of 600 μm possessed the better capability to induce new bone formation. Therefore, for the design of Ti6Al4V alloy with a regular porous scaffold, the surface morphology, porosity, strength, and elastic modulus should be considered systematically, which would determine the capability of osteoinduction and osteogenesis.

Minimally invasive management of pathologic fractures of the pelvis and sacrum: Tumor ablation and fracture stabilization

BACKGROUND

Pathologic fractures of the pelvis/sacrum due to metastatic bone disease (MBD) cause pain and dysfunction due to mechanical instability of the pelvic ring. This study presents our multi-institutional experience with percutaneous stabilization of pathologic fractures and osteolytic lesions from MBD throughout the pelvic ring.

METHODS

The records of patients undergoing this procedure from 2018 to 2022 were reviewed retrospectively from two institutions. Surgical data and functional outcomes were recorded.

RESULTS

Fifty-six patients underwent percutaneous stabilization, with a median operative duration of 119 min (interquartile range [IQR]: 92.8, 167) and median estimated blood loss of 50 mL (IQR: 20, 100). The median length of stay was 3 days (IQR: 1, 6), and 69.6% (n = 39) of patients were discharged home. Early complications included one partial lumbosacral plexus injury, three acute kidney injuries, and one case of intra-articular cement extravasation. Late complications included two infections and one revision stabilization procedure for hardware failure. Mean Eastern Cooperative Oncology Group (ECOG) scores improved from 3.02 (SD 0.8) preoperatively to 1.86 (SD 1.1) postoperatively (p < 0.001). Ambulatory status also improved (p < 0.001).

CONCLUSIONS

Percutaneous stabilization of pathologic fractures and osteolytic defects of the pelvis and sacrum is a procedure that improves patient function, ambulatory status and is associated with a limited complication profile.

Operative management of metastatic disease of the acetabulum: review of the literature and prevailing concepts

Metastatic disease of the periacetabular region is a common problem in orthopaedic oncology, associated with severe pain, decreased mobility, and substantial decline of the quality of life. Conservative management includes optimisation of pain management, activity modification, and radiation therapy. However, patients with destructive lesions affecting the weight-bearing portion of the acetabulum often require reconstructive surgery to decrease pain and restore mobility. The goal of surgery is to provide an immediately stable and durable construct, allowing immediate postoperative weight-bearing and maintaining functional independence for the remaining lifetime of the patient. A variety of surgical techniques have been reported, most of which are based upon cemented total hip arthroplasty, but also include porous tantalum implants and percutaneous cementoplasty. This review discusses the various reconstructive concepts and options, including their respective indications and outcome. A reconstructive algorithm incorporating different techniques and strategies based upon location and quality of remaining bone is also presented.

A novel biomimetic trabecular bone metal plate for bone repair and osseointegration

Fracture is one of the most common traumatic diseases in clinical practice, and metal plates have always been the first choice for fracture treatment because of their high strength. However, the bone plates have high elastic modulus and do not match the biomechanics of human bone, which adversely affects callus formation and fracture healing. Moreover, the complex microenvironment in the human body can induce corrosion of metallic materials and release toxic ions, which reduces the biocompatibility of the bone plate, and may necessitate surgical removal of the implant. In this study, tantalum (Ta) was deposited on porous silicon carbide (SiC) scaffolds by chemical vapor deposition technology to prepare a novel porous tantalum (pTa) trabecular bone metal plate. The function of the novel bone plate was evaluated by implantation in an animal fracture model. The results showed that the novel bone plate was effective in fracture fixation, without breakage. Both X-ray and microcomputed tomography analysis showed indirect healing by both pTa trabecular bone metal plates and titanium (Ti) plates; however, elastic fixation and obvious callus formation were observed after fixation with pTa trabecular bone metal plates, indicating better bone repair. Histology showed that pTa promoted the formation of new bone and integrated well with the host bone. Therefore, this novel pTa trabecular bone metal plate has good prospects for application in treating fractures.

Surgical robot-assisted tripod percutaneous reconstruction technique combined with bone cement filling technique for the treatment of acetabular metastasis

Background: Acetabular metastasis is a type of metastatic bone cancer, and it mainly metastasizes from cancers such as lung cancer, breast cancer, and renal carcinoma. Acetabular metastasis often causes severe pain, pathological fractures, and hypercalcemia which may seriously affect the quality of life of acetabular metastasis patients. Due to the characteristics of acetabular metastasis, there is no most suitable treatment to address it. Therefore, our study aimed to investigate a novel treatment technique to relieve these symptoms. Methods: Our study explored a novel technique to reconstruct the stability of the acetabular structure. A surgical robot was used for accurate positioning and larger-bore cannulated screws were accurately inserted under the robot's guidance. Then, the lesion was curetted and bone cement was injected through a screw channel to further strengthen the structure and kill tumor cells. Results: A total of five acetabular metastasis patients received this novel treatment technique. The data relating to surgery were collected and analyzed. The results found that this novel technique can significantly reduce operation time, intraoperative bleeding, visual analogue score scores, Eastern Cooperative Oncology Group scores, and postoperative complications (e.g., infection, implant loosening, hip dislocation) after treatment. Follow-up time ranged from 3 months to 6 months, and the most recent follow-up results showed that all patients survived and no acetabular metastasis progressed in any of the patients after surgery. Conclusion: Surgical robot-assisted tripod percutaneous reconstruction combined with the bone cement filling technique may be a novel and suitable treatment in acetabular metastasis patients. Our study may provide new insights into the treatment of acetabular metastasis.

Augmenting Pathologic Acetabular Bone Loss With Photodynamic Nails to Support Primary Total Hip Arthroplasty

Background

Pathologic acetabular defects can undermine the stability and osseointegration of a primary total hip arthroplasty (THA) acetabular component. Our service has used photodynamic nails (PDNs) in a modified Harrington technique to provide space-filling stability to a primary acetabular implant without impeding local osseointegration. Here we describe our experience with PDN-augmented THAs.

Methods

An institutional review board-approved retrospective analysis of all patients who underwent PDN-augmented THA in the management of severe (Harrington class II or III) acetabular defects from September 1, 2020 to May 1, 2021 with at least 6 months of follow-up was performed. The primary outcome was implant survivorship. Comparisons between preoperative and 6-week postoperative visual analogue pain scores were made using the Mann-Whitney U test.

Results

Six patients were included in this case series, 5 with metastatic cancer and 1 with pelvic discontinuity and avascular necrosis following failed attempted acetabular fixation. The mean follow-up duration was 10.3 ± 4.3 months. The mean age was 75.5 ± 4.7 years, mean body mass index 27.3 ± 5.6, and 5 patients were female. All but 1 patient was American Society of Anesthesiologists (ASA) class III. Two patients required acetabular revisions, one for aseptic loosening and a second for a pathologic fracture secondary to disease progression. One patient passed away 90 days after the procedure. The mean visual analogue pain score significantly improved from 7.8 ± 1.6 to 2.0 ± 1.4 six weeks after surgery (P = .008).

Conclusions

PDN augmentation of the periacetabular bone of patients with large pelvic defects yields durable pain relief and function in vulnerable hosts. PDN should be considered a part of the reconstructive surgeon’s armamentarium.

Skeletal metastatic disease of the acetabulum: historical and evolving techniques for management

The skeleton is the third most common organ system to be involved in the spread of metastatic carcinomas. More options for systemic therapies, surgeries and adjuvant treatments are providing longer survival for patients with known metastatic carcinoma to the bone. This means more patients are living with metastatic skeletal disease than ever before. If metastatic disease results in enough bone loss it can cause significant pain and dysfunction for patients. The acetabulum and pelvis are common sites of metastatic disease. The complex anatomy of the bony pelvis and acetabulum, as well as its proximity to important neurovascular and pelvic structures, can make surgical management of acetabular metastatic disease technically difficult. Decision making for patients with symptomatic skeletal metastatic disease is complex, and multidisciplinary teams can be helpful in providing appropriate care for these patients. Systemic chemotherapies, immunotherapies or targeted therapies may not adequately treat large areas of metastatic disease in the hip and pelvis. Radiation therapy is not successful for all patients. Fortunately, there are evolving therapies that are giving patients and providers more options for treatment. This review article will cover some of those new therapies and their outcomes, focusing on newer ablative, minimally invasive and surgical reconstruction techniques for metastatic disease involving the acetabulum. Decision making in the management of a patient's metastatic acetabular disease is still made on a case by case basis. This review article hopefully will remind clinicians of the variety of treatments available to these patients.

Outcomes of Hip Reconstruction for Metastatic Acetabular Lesions: A Scoping Review of the Literature

(1) Background: Management of metastatic periacetabular lesions remains a challenging area of orthopaedics. This study aims to evaluate and summarize the currently available reconstructive modalities, including their indications and outcomes. (2) Methods: A scoping review was carried out in accordance with PRISMA guidelines. Medline, EMBASE, and Cochrane were searched for relevant articles. (3) Results: A total of 18 papers met inclusion criteria encompassing 875 patients. The most common primary malignancy was breast (n = 230, 26.3%). Reconstruction modalities used were total hip arthroplasty (n = 432, 49.1%), the Harrington procedure (n = 374, 42.5%), modular hemipelvic endoprotheses (n = 63, 7.2%) and a reverse ice-cream cone prosthesis (n = 11, 1.25%). (4) Conclusions: Advances in implant design including use of dual mobility or flanged cups, tantalum implants, and modular hemipelvic endoprostheses allow for larger acetabular defects to be addressed with improved patient outcomes. This armamentarium of reconstruction options allows for tailoring of the procedure performed depending on patient factors and extent of periacetabular disease.

Reconstruction with a cage outlives patients with metastatic disease involving the acetabulum

AIM

The aim of this study was to determine whether patients treated with a caged reconstruction for metastatic acetabular disease would have a construct survival superior to that of their life expectancy.

PATIENTS AND METHODS

We undertook a retrospective study, in a single centre in the United Kingdom, reviewing outcomes for 19 patients (20 hips) treated with a cage reconstruction for metastatic disease of their acetabulum over 6 years. Inclusion criteria were those with an impending fracture of the acetabulum, metastatic dissociation, fracture of the acetabulum and or femur and those whose life expectancy was considered by the oncology team to be >6 months.

RESULTS

In all patients the Restoration GAP II acetabular cage (Stryker, Howmedica Osteonics Corp, NJ, USA) was used in conjunction with a cemented acetabular cup and cemented femoral stem. The mean age at the time of surgery was 68 (44-87) years with breast cancer being the most common primary malignancy (31%) followed by prostate cancer (26%).Radiological survivorship estimates were 94.1% (95% CI, 99.2-65.0) at 12 and 24 months, 70.6% (95% CI, 93.6-16.0) at 36 months and 35.3% (95% CI, 78.2-1.2) at 48 months. There were 3 radiological failures of the implant due to disease progression. Complications occurred in 3 patients with 2 developing deep infection which was treated with suppressive antibiotic therapy following aspiration of the hip. 1 patient suffered a hip dislocation following trauma which was successfully reduced closed and no further intervention was required.

CONCLUSIONS

This study represents the first published case series of the use of the GAP II cage in patients with metastatic acetabular disease. The construct generally outlives the patient and hence is suitable for the treatment of acetabular metastases.

The Harrington Plus Reconstruction for Pelvic and Acetabular Metastases

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The Harrington Plus reconstruction is a modification of the original Harrington rod technique for reconstruction of extensive periacetabular metastases. This procedure was developed in our institution.

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An intrapelvic suprapectineal plate is used, with the aim of reconstructing a disrupted anterior column and reducing the risk of failure in cases where there is extensive medial bone loss.

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This paper describes the outcomes of patients who have undergone this procedure to date.

Background

Surgical management of periacetabular bone metastases is challenging. The Harrington Plus reconstruction is a modification of the original Harrington rod technique. An intrapelvic suprapectineal plate is used, with the aim of reconstructing a disrupted anterior column and reducing the risk of failure in cases where there is extensive medial bone loss.

Methods

A retrospective review of the 13 patients who have undergone the Harrington Plus procedure to date was performed. Mobility status, EQ5D and Oxford Hip scores were assessed.

Results

There was a significant improvement in mobility status, EQ5D and Oxford Hip Scores at 6 months postoperatively (p < 0.05). Two patients returned to theatre for debridement of infection. There were no postoperative dislocations, cup medialisation or cases of loosening of the prosthesis. No patient required revision arthroplasty surgery.

Conclusion

The Harrington Plus procedure produces a reliable construct that allows patients with extensive periacetabular metastatic defects to fully weight-bear. Careful patient selection and multidisciplinary management is essential.

What's new in the management of metastatic bone disease

Metastatic bone disease is a common complication of malignant tumours. As cancer treatment improves the overall survival of patients, the number of patients with bone metastases is expected to increase. The treatments for bone metastases include surgery, radiotherapy, and bone-modifying agents, with patients with a short expected prognosis requiring less invasive treatment. Patients with metastatic bone disease show greatly varying primary tumour histology, metastases sites and numbers, and comorbidities. Therefore, randomised clinical trials are indispensable to compare treatments for these patients. This editorial reviews recent findings on the diagnosis and prognosis prediction and discusses the current treatment of patients with metastatic bone disease.

Influence of porous tantalum scaffold pore size on osteogenesis and osteointegration: A comprehensive study based on 3D-printing technology

The emerging role of porous tantalum (Ta) scaffold for bone tissue engineering is noticed due to its outstanding biological properties. However, it is controversial which pore size and porosity are more conducive for bone defect repair. In the present work, porous tantalum scaffolds with pore sizes of 100-200, 200-400, 400-600 and 600-800 μm and corresponding porosities of 25%, 55%, 75%, and 85% were constructed, using computer aided design and 3D printing technologies, then comprehensively studied by in vitro and in vivo studies. We found that Ta scaffold with pore size of 400-600 μm showed stronger ability in facilitating cell adhesion, proliferation, and osteogenic differentiation in vitro. In vivo tests identified that porous tantalum scaffolds with pore size of 400-600 μm showed better performance of bone ingrowth and integration. In mechanism, computational fluid dynamics analysis proved porous tantalum scaffolds with pore size of 400-600 μm hold appropriate permeability and surface area, which facilitated cell adhesion and proliferation. Our results strongly indicate that pore size and porosity are essential for further applications of porous tantalum scaffolds, and porous tantalum scaffolds with pore size 400-600 μm are conducive to osteogenesis and osseointegration. These findings provide new evidence for further application of porous tantalum scaffolds for bone defect repair.

Current Overview of Treatment for Metastatic Bone Disease

The number of patients with bone metastasis increases as medical management and surgery improve the overall survival of patients with cancer. Bone metastasis can cause skeletal complications, including bone pain, pathological fractures, spinal cord or nerve root compression, and hypercalcemia. Before initiation of treatment for bone metastasis, it is important to exclude primary bone malignancy, which would require a completely different therapeutic approach. It is essential to select surgical methods considering the patient’s prognosis, quality of life, postoperative function, and risk of postoperative complications. Therefore, bone metastasis treatment requires a multidisciplinary team approach, including radiologists, oncologists, and orthopedic surgeons. Recently, many novel palliative treatment options have emerged for bone metastases, such as stereotactic body radiation therapy, radiopharmaceuticals, vertebroplasty, minimally invasive spine stabilization with percutaneous pedicle screws, acetabuloplasty, embolization, thermal ablation techniques, electrochemotherapy, and high-intensity focused ultrasound. These techniques are beneficial for patients who may not benefit from surgery or radiotherapy.

Bone screws of porous silicon carbide coated with tantalum improve osseointegration and osteogenesis in goat femoral neck fractures

Traditional metal materials, such as stainless steel and titanium (Ti) alloys, are still the gold standards for fracture fixation. However, the elastic moduli of these materials differ from that of human cortical bone, and the stress shielding effect affects fracture healing, leading to secondary fractures. Herein, a new porous Ta coated SiC (pTa-SiC) scaffold using in internal fixation devices with good mechanical and biological properties was prepared based on porous silicon carbide (SiC) scaffold and tantalum (Ta) metal. The osteogenic and osseointegration properties of the pTa-SiC scaffold were investigated by bothin vitroandin vivotests. The results showed that compared with porous titanium (pTi), the pTa-SiC promoted the proliferation, migration, and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells. Moreover, the internal fixation tests were carried out in a goat load-bearing femoral neck fracture model. Histological results showed good osseointegration around the pTa-SiC screws. And the acid etching results showed that bone cells grew tightly on the pTa-SiC throughout bone canaliculi, and the growth mode was contact osteogenesis, which indicated good biological fixation effects. Therefore, it is reasonable to be expected that the new pTa-SiC scaffold with excellent mechanical and biological properties could be a promising candidate for bone implant field.

Emerging Concepts in the Surgical Management of Peri-Acetabular Metastatic Bone Disease

The pelvis is a common site of metastatic bone disease. Peri-acetabular lesions are particularly challenging and can cause severe pain, disability and pathologic fractures. Surgical management of these lesions has historically consisted of cementoplasty for contained lesions and Harrington reconstructions for larger, more destructive lesions. Due to the limitations of these procedures, a number of novel procedures have been developed to manage this challenging problem. Percutaneous techniques—including acetabular screw fixation and cementoplasty augmented with screws—have been developed to minimize surgical morbidity. Recent literature has demonstrated a reliable reduction in pain and improvement in function in appropriately selected patients. Several adjuncts to the Harrington procedure have been utilized in recent years to reduce complication rates. The use of constrained liners and dual mobility bearings have reduced the historically high dislocation rates. Cage constructs and porous tantalum implants are becoming increasingly common in the management of large bony defects and destructive lesions. With novel and evolving surgical techniques, surgeons are presented with a variety of surgical options to manage this challenging condition. Physicians must take into account the patients’ overall health status, oncologic prognosis and anatomic location and extent of disease when developing an appropriate surgical plan.

Investigation of Cytotoxicity, Oxidative Stress, and Inflammatory Responses of Tantalum Nanoparticles in THP-1-Derived Macrophages

Tantalum (Ta) is gaining attention as a biomaterial in bone tissue engineering. Although the clinical advantage of Ta-based implants for primary and revision total joint replacement (TJA) has been well documented, few studies investigated the effect of wear products of Ta implants on peri-implant cells, and their potential contribution to aseptic implant loosening. This study is aimed at examining the cytotoxicity, oxidative stress, and proinflammatory potential of Ta and TiO₂ nanoparticles (NPs) on macrophages in vitro. NPs were characterized using scanning electron microscopy, dynamic light scattering, and energy-dispersive X-ray. To test the NP-mediated cellular response in macrophages, THP-1-derived macrophages were challenged with both NPs, and cytotoxicity was analyzed using CCK-8 and LDH assays. Flow cytometry was used to investigate particle uptake and their internalization routes. NP-mediated oxidative stress was investigated by measuring the production of reactive oxygen species, and their proinflammatory potential was determined by quantifying the production of TNFα and IL-1β in cell culture supernatants using ELISA. We found that both Ta and TiO₂ NPs were taken up through actin-dependent phagocytosis, although TiO₂ NPs did also show some involvement of macropinocytosis and clathrin-mediated endocytosis. Ta NPs caused no apparent toxicity, while TiO₂ NPs demonstrated significant cytotoxicity at a concentration of over 100μg/mL at 24 h. Ta NPs induced negligible ROS generation and proinflammatory cytokines (TNFα, IL-1β) in macrophages. In contrast, TiO₂ NPs markedly induced these effects in a dose-dependent manner. Our findings indicate that Ta NPs are inert, nontoxic, and noninflammatory. Therefore, Ta could be considered an excellent biomaterial in primary and revision joint arthroplasty implants.

Hip Arthroplasty Following Subtotal Sacrectomy for Chordoma

BACKGROUND/AIM

Chordomas often affect the sacrum with a high predilection for local-regional recurrence. Patients typically retain their ability to ambulate, and the development of metastatic disease in the periacetabular region can have significant morbidity and pain with ambulation. The purpose of the study was to describe the outcome of patients undergoing a hip arthroplasty following resection of a sacral chordoma.

PATIENTS AND METHODS

From 1990 to 2015, 84 patients underwent sacrectomy for chordoma, while four of these (5%) patients underwent hip arthroplasty. The most common level of nerve root sacrifice was S2-5 (n=2). The mean time between sacrectomy and hip arthroplasty was 7 years. Indications for arthroplasty included metastatic disease (n=3) and coxarthrosis (n=1).

RESULTS

Postoperatively two patients ambulated with a gait aid, and no patient had a Trendelenburg gait. The mean Harris Hip Score significantly improved from 49 to 80 postoperatively (p=0.02).

CONCLUSION

The results of this study indicate that hip arthroplasty is a durable treatment option for patients with metastatic disease or coxarthrosis following subtotal sacrectomy for chordoma.