Five-Year Follow-Up of Distal Tibia Bone and Foot and Ankle Trauma Treated with a 3D-Printed Titanium Cage

Cortico-cancellous osseointegration into additively manufactured titanium implants using a load-bearing femoral ovine model

Introduction: Titanium-based implants can be used to fill voids in bone reconstruction surgery. Through additive manufacturing (AM), it is possible to produce titanium implants with osteoconductive properties such as high porosity and low stiffness. AM facilitates a level of design flexibility and personalization that is not feasible with traditional techniques. Methods: In this study, osseointegration into titanium alloy (Ti-6Al-4V) lattices was investigated for 12 weeks post-implantation using a novel bicortical load-bearing ovine model. The objective was to assess the safety and efficacy of AM-fabricated implants using two lattice structures of contrasting stiffness spanning the full width of the femoral condyle. Results: This was achieved by evaluating implant osseointegration and bone-implant contact properties by histomorphometry, scoring local implant tissue responses via histopathology, and micro-computed tomography reconstruction. Discussion: We found that Ti-6Al-4V implants facilitated widespread and extensive osseointegration, with bone maturation ongoing at the conclusion of the trial period. Following the implantation period, no adverse clinical indications that could be directly ascribed to the presence of the implanted device were identified, as determined by macroscopic and microscopic observation.

3D-printed titanium porous prosthesis combined with the Masquelet technique for the management of large femoral bone defect caused by osteomyelitis

BACKGROUND

The treatment of infected bone defects remains a clinical challenge. With the development of three-dimensional printing technology, three-dimensional printed implants have been used for defect reconstruction. The aim of this study was to investigate the clinical outcomes of three-dimensional printed porous prosthesis in the treatment of femoral defects caused by osteomyelitis.

METHODS

Eleven patients with femoral bone defects following osteomyelitis who were treated with 3D-printed porous prosthesis at our institution between May 2017 and July 2021, were included. Eight patients were diagnosed with critical-sized defects, and the other three patients were diagnosed with shape-structural defects. A two-stage procedure was performed for all patients, and the infection was eradicated and bone defects were occupied by polymethylmethacrylate spacer during the first stage. The 3D-printed prosthesis was designed and used for the reconstruction of femoral defects in the second stage. Position of the reconstructed prostheses and bone growth were measured using radiography. The union rate, complications, and functional outcomes at the final follow-up were assessed.

RESULTS

The mean length of the bone defect was 14.0 cm, union was achieved in 10 (91%) patients. All patients showed good functional performance at the most recent follow-up. In the critical-sized defect group, one patient developed a deep infection that required additional procedures. Two patients had prosthetic dislocations. Radiography demonstrated good osseous integration of the implant-bone interface in 10 patients.

CONCLUSION

The 3D printed prostheses enable rapid anatomical and mechanically stable reconstruction of extreme femur bone defects, effectively shortens treatment time, and achieves satisfactory clinical outcomes.

Orthopaedic Advances: Use of Three-Dimensional Metallic Implants for Reconstruction of Critical Bone Defects After Trauma

Multiple successful strategies exist for the management of critical-sized bone defects. Depending on the location and etiology of an osseous defect, there are nuances that must be considered by the treating surgeon. The induced membrane technique and various modifications of the Ilizarov method (bone transport by distraction osteogenesis) have been the most common methods for biologic reconstruction. Despite the versatility and high union rates reported, they may not be practical for every patient. The rapid expansion of three-dimensional printing of medical devices has led to an increase in their use within orthopaedic surgery, specifically in the definitive treatment of critical bone defects. This article proposes indications and contraindications for implementation of this technology and reviews the available clinical evidence on the use of custom nonresorbable implants for the treatment of traumatic bone loss. Clinical cases are presented to illustrate the scenarios in which this approach is viable.

A modified hybrid transport technique combined with a retrograde tibiotalocalcaneal arthrodesis nail for the management of distal tibial periarticular osteomyelitis and associated defects

BACKGROUND

This paper aimed to propose a modified technique of bone transport. An annular frame combined with a retrograde tibiotalocalcaneal arthrodesis nail was used in this novel technique for treating large distal tibial periarticular osteomyelitis and associated defects.

METHODS

Our team conducted a retrospective research. Forty-three patients with large distal tibial periarticular bone loss were involved in this study. Sixteen patients were treated using the modified hybrid transport technique (MHT group) while 27 were subjected to traditional bone transport (BT group). The mean bone loss was 7.8 ± 2.4 cm in the MHT group and 7.6 ± 2.6 cm in the BT group. The external fixation index, time in transport frame, self-rating anxiety scale, bone healing results and postoperative complications were recorded.

RESULTS

The mean time in frame for the MHT group was 3.6 ± 1.5 months, while that of the BT group was 10.3 ± 2.7 months (p < 0.05). The mean external fixation index of MHT group was 0.46 ± 0.08 months/cm versus 1.38 ± 0.24 months/cm of the BT group (p < 0.05). There was no statistical difference for the bone healing results between the MHT and BT groups (p = 0.856). The self-rating anxiety scale and total complication incidence of the MHT group were significantly lower than that of BT patients (p < 0.05).

CONCLUSION

Compared to the traditional BT technique, our modified hybrid transport technique showed better clinical outcomes for treating large distal tibial periarticular bone loss, including less time in transport frame, lower external fixation index and complication incidence. Therefore, this modified technique should be further promoted and developed.

Treatment of an Infected Tibial Shaft Non-Union Using a Novel 3D-Printed Titanium Mesh Cage: A Case Report

Treating large bone defects resulting from trauma, tumors, or infection can be challenging, as current methods such as external fixation with bone transport, bone grafting, or amputation often come with high costs, high failure rates, high requirements for follow-up, and potential complications. In this case report, we present the successful treatment of a complicated, infected tibial shaft non-union by using a personalized three-dimensional (3D)-printed titanium mesh cage. This case adds to the existing body of literature by demonstrating successful integration of bone into a titanium implant and a demonstration of immediate postoperative weight bearing in the setting of suboptimal operative and psychosocial conditions. Futhermore, this report highlights the flexibility of 3D-printing technology and its ability to allow for continued limb salvage, even after a planned bone transport procedure has been interrupted. The use of 3D-printed implants customized to the patient's specific needs offers a promising new avenue for treating complex tibial pathologies, and the technology's versatility and ability to be tailored to individual patients makes it a promising tool for addressing a wide range of bone defects.

Three-Year Follow-Up of a Traumatic Critical-Sized Tibial Bone Defect Treated with a 3D Printed Titanium Cage: A Case Report

CASE

We report a case involving a 21-year-old woman who sustained a Grade III open pilon fracture of the left ankle during a motor vehicle accident that resulted in a 12-cm critical-sized bone defect (CSD) that was successfully treated with a three-dimensional (3D) printed titanium alloy (Ti-6Al-4V) cage, a tibiotalocalcaneal intramedullary nail, and autogenous and allograft bone. The patient's reported outcome measures were comparable with those reported for non-CSD injuries at 3-year follow-up. The authors conclude that 3D printed titanium cages offers a unique approach to traumatic limb salvage for tibial CSD.

CONCLUSIONS

3D printing offers a novel solution to CSDs. To the best of our knowledge, this case report details the largest 3D printed cage, to date, used to treat tibial bone loss. This report describes a unique approach to traumatic limb salvage with favorable patient-reported outcomes and evidence of radiographic fusion at a 3-year follow up.

Repair of critical diaphyseal defects of lower limbs by 3D printed porous Ti6Al4V scaffolds without additional bone grafting: a prospective clinical study

The repair of critical diaphyseal defects of lower weight-bearing limbs is an intractable problem in clinical practice. From December 2017, we prospectively applied 3D printed porous Ti6Al4V scaffolds to reconstruct this kind of bone defect. All patients experienced a two-stage surgical process, including thorough debridement and scaffold implantation. With an average follow-up of 23.0 months, ten patients with 11 parts of bone defects were enrolled in this study. The case series included three females and seven males, their defect reasons included seven parts of osteomyelitis and four parts of aseptic nonunion. The bone defects located at femur (five parts) and tibia (six parts), with an average defect distance of 12.2 cm. Serial postoperative radiologic follow-ups displayed a continuous process of new bone growing and remodeling around the scaffold. One patient suffered tibial varus deformity, and he underwent a revision surgery. The other nine patients achieved scaffold stability. No scaffold breakage occurred. In conclusion, the implantation of 3D printed Ti6Al4V scaffold was feasible and effective to reconstruct critical bone defects of lower limbs without additional bone grafting. Graphical abstract.

Influence of different fixation modes on biomechanical conduction of 3D printed prostheses for treating critical diaphyseal defects of lower limbs: A finite element study

Background

Applying 3D printed prostheses to repair diaphyseal defects of lower limbs has been clinically conducted in orthopedics. However, there is still no unified reference standard for which the prosthesis design and fixation mode are more conducive to appropriate biomechanical conduction.

Methods

We built five different types of prosthesis designs and fixation modes, from Mode I to Mode V. Finite element analysis (FEA) was used to study and compare the mechanical environments of overall bone-prosthesis structure, and the maximum stress concentration were recorded. Additionally, by comparing the maximum von Mises stress of bone, intramedullary (IM) nail, screw, and prosthesis with their intrinsic yield strength, the risk of fixation failure was further clarified.

Results

In the modes in which the prosthesis was fixed by an interlocking IM nail (Mode I and Mode IV), the stress mainly concentrated at the distal bone-prosthesis interface and the middle-distal region of nail. When a prosthesis with integrally printed IM nail and lateral wings was implanted (Mode II), the stress mainly concentrated at the bone-prosthesis junctional region. For cases with partially lateral defects, the prosthesis with integrally printed wings mainly played a role in reconstructing the structural integrity of bone, but had a weak role in sharing the stress conduction (Mode V). The maximum von Mises stress of both the proximal and distal tibia appeared in Mode III, which were 18.5 and 47.1 MPa. The maximum peak stress shared by the prosthesis, screws and IM nails appeared in Mode II, III and I, which were 51.8, 87.2, and 101.8 MPa, respectively. These peak stresses were all lower than the yield strength of the materials themselves. Thus, the bending and breakage of both bone and implants were unlikely to happen.

Conclusion

For the application of 3D printed prostheses to repair diaphyseal defects, different fixation modes will lead to the change of biomechanical environment. Interlocking IM nail fixation is beneficial to uniform stress conduction, and conducive to new bone regeneration in the view of biomechanical point. All five modes we established have reliable biomechanical safety.

Mechanical Distribution and New Bone Regeneration After Implanting 3D Printed Prostheses for Repairing Metaphyseal Bone Defects: A Finite Element Analysis and Prospective Clinical Study

Critical metaphyseal bone defects caused by nonunion and osteomyelitis are intractable to repair in clinical practice owing to the rigorous demanding of structure and performance. Compared with traditional treatment methods, 3D printing of customized porous titanium alloy prostheses offer feasible and safe opportunities in repairing such bone defects. Yet, so far, no standard guidelines for optimal 3D printed prostheses design and fixation mode have been proposed to further promote prosthesis stability as well as ensure the continuous growth of new bone. In this study, we used a finite element analysis (FEA) to explore the biomechanical distribution and observed new bone regeneration in clinical practice after implanting 3D printed prostheses for repairing metaphyseal bone defects. The results reflected that different fixation modes could result in diverse prosthesis mechanical conductions. If an intramedullary (IM) nail was applied, the stress mainly conducted equally along the nail instead of bone and prosthesis structure. While the stress would transfer more to the lateral bone and prosthesis’s body when the printed wing and screws are selected to accomplish fixation. All these fixation modes could guarantee the initial and long-term stability of the implanted prosthesis, but new bone regenerated with varying degrees under special biomechanical environments. The fixation mode of IM nail was more conducive to new bone regeneration and remodeling, which conformed to the Wolff’s law. Nevertheless, when the prosthesis was fixed by screws alone, no dense new callus could be observed. This fixation mode was optional for defects extremely close to the articular surface. In conclusion, our innovative study could provide valuable references for the fixation mode selection of 3D printed prosthesis to repair metaphyseal bone defect.

Advances in the Application of Three-dimensional Printing for the Clinical Treatment of Osteoarticular Defects

As a promising manufacturing technology, three-dimensional (3D) printing technology is widely used in the medical field. In the treatment of osteoarticular defects, the emergence of 3D printing technology provides a new option for the reconstruction of functional articular surfaces. At present, 3D printing technology has been used in clinical applications such as models, patient-specific instruments (PSIs), and customized implants to treat joint defects caused by trauma, sports injury, and tumors. This review summarizes the application status of 3D printing technology in the treatment of osteoarticular defects and discusses its advantages, disadvantages, and possible future research strategies.

Treatment of Severe Avascular Necrosis of the Talus Using a Novel Keystone-Shaped 3D-Printed Titanium Truss Implant

BACKGROUND

Avascular necrosis (AVN) of the talus most commonly occurs secondary to trauma. Significant bone loss and collapse in severe talar AVN remains an operative challenge. Tibiotalocalcaneal arthrodesis (TTC) using femoral head allograft is at risk of collapse and subsidence. The use of a void-filling titanium truss can mitigate against this. This study describes the use of a novel keystone shaped 3D-printed titanium truss for treatment of severe talar AVN.

METHODS

Three patients with end-stage AVN of the talus were included. Each patient underwent a TTC arthrodesis with a custom-made, 3D-printed, keystone-shaped, truss implant in conjunction with a hindfoot intramedullary nail. Modified patient American Orthopaedic Foot & Ankle Society (AOFAS) scores were recorded at the preoperative, 6-month, 12-month, and annual postoperative timepoints.

RESULTS

All patients progressed to satisfactory radiological union by one year. Mean follow up time was 32 months (24-48 months). Mean preoperative modified AOFAS score was 5. There was progressive improvement in AOFAS scores from 6 months postoperatively. Mean modified AOFAS score improved from 28 at 6 months to 37 at 2 years postoperatively.

CONCLUSION

Custom-made 3D-printed titanium trusses provide promising outcomes for treating severe AVN of the talus. The "keystone" design is advantageous as it allows for bone stock preservation and conforms to the shape of the native calcaneum. All patients showed progressive improvements in outcomes at sequential time intervals postoperatively. The implant provides a strong mechanical structure resisting collapse and subsidence during the arthrodesis process.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

From Patient to Procedure: The Process of Creating a Custom 3D-Printed Medical Device for Foot and Ankle Pathology

Three-dimensional (3D) printing technology has advanced greatly over the past decade and is being used extensively throughout the field of medicine. Several orthopaedic surgery specialties have demonstrated that 3D printing technology can improve patient care and physician education. Foot and ankle pathology can be complex as the 3D anatomy can be challenging to appreciate. Deformity can occur in several planes simultaneously and bone defects either from previous surgery or trauma can further complicate surgical correction. Three-dimensional printing technology provides an avenue to tackle the challenges associated with complex foot and ankle pathology. A basic understanding of how these implants are designed and made is important for surgeons as this technology is becoming more widespread and the clinical applications continue to grow within foot and ankle surgery.Levels of Evidence: Level V.