Quantitative radiographic analysis of fiber reinforced polymer composites

Carbon-fibre plates for traumatic and (impending) pathological fracture fixation: Where do we stand? A systematic review

BACKGROUND

Carbon-fibre (CF) plates are increasingly used for fracture fixation. This systematic review evaluated complications associated with CF plate fixation. It also compared outcomes of patients treated with CF plates versus metal plates, aiming to determine if CF plates offered comparable results. The study hypothesized that CF plates display similar complication rates and clinical outcomes as metal plates for fracture fixation.

METHODS

The study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The following databases were searched from database inception until June 2023: PubMed, MEDLINE, Embase, Web of Science, Cochrane Library, Emcare, Academic Search Premier and Google Scholar. Studies reporting on clinical and radiological outcomes of patients treated with CF plates for traumatic fractures and (impending) pathological fractures were included. Study quality was assessed, and complications were documented as number and percentage per anatomic region.

RESULTS

A total of 27 studies of moderate to very low quality of evidence were included. Of these, 22 studies (800 patients, median follow-up 12 months) focused on traumatic fractures, and 5 studies (102 patients, median follow-up 12 months) on (impending) pathological fractures. A total of 11 studies (497 patients, median follow-up 16 months) compared CF plates with metal plates. Regarding traumatic fractures, the following complications were mostly reported: soft tissue complications (52 out of 391; 13%) for the humerus, structural complications (6 out of 291; 2%) for the distal radius, nonunion and structural complication (1 out of 34; 3%) for the femur, and infection (4 out of 104; 4%) for the ankle. For (impending) pathological fractures, the most frequently reported complications were infections (2 out of 14; 14%) for the humerus and structural complication (6 out of 86; 7%) for the femur/tibia. Comparative studies reported mixed results, although the majority (7 out of 11; 64%) reported no significant differences in clinical or radiological outcomes between patients treated with CF or metal plates.

CONCLUSION

This systematic review did not reveal a concerning number of complications related to CF plate fixation. Comparative studies showed no significant differences between CF plates and metal plates for traumatic fracture fixation. Therefore, CF plates appear to be a viable alternative to metal plates. However, high-quality randomized controlled trials (RCTs) with long-term follow-up are strongly recommended to provide additional evidence supporting the use of CF plates.

LEVEL OF EVIDENCE

III, systematic review.

Complications of patients with bone tumors treated with carbon-fiber plates: an international multicenter study

Carbon-fiber (CF) plates are a promising alternative to metal plates. However, reported experience in orthopaedic oncology remains limited. The aim of this study was to identify complications of patients with bone tumors treated with CF plates. Between February 2015 and May 2021, 13 centers retrospectively registered patients with bone tumors that were reconstructed using CF plates. Complications were identified, and timing and etiology of complications were noted. Similar complications were tabulated and classified based on mechanical, non-mechanical and paediatric complications. Mechanical complications included: (1) aseptic loosening or graft-host non-union, and (2) structural complications. Non-mechanical complications included: (3) soft tissue complications, (4) infection and (5) tumor progression. Specific paediatric complications included (6) growth arrest resulting in longitudinal or angular deformity. Ninety-six patients were included with a median follow-up time of 35 months. In total, 22 (23%) patients had complications. Mechanical complications included: 1 (1%) aseptic loosening, 2 (2%) non-unions, and 7 (7%) structural complications. Non-mechanical complications included 1 (1%) soft tissue complication, 4 (4%) infections and 5 (5%) tumor progressions. Paediatric complications occurred in 2 (2%) patients. This study suggests CF plates are safe to use in demanding reconstructions after bone tumor resections, presenting a seemingly low complication profile.

Comparison between Areas of Bone Visualization Using Radiolucent Hybrid Fixator Frames and Graphically Simulated Metallic Frames: An Ex Vivo Study

The objective of this study is to evaluate the difference between the amount of bone visible with the superimposition of a radiolucent hybrid external fixator and a graphically simulated metallic frame. Eighteen frames were applied to eighteen bone specimens. The fracture area (FA), the radiolucent area (RLA) and the radiopaque area (ROA) inside the FA were calculated for each construct on both postoperative views. The ratio between the RLA and FA and between the ROA and FA was used to evaluate the amount of bone visible in the FA with a radiolucent and a radiopaque fixator, respectively. Finally, the areas of RLA and ROA were compared using the Wilcoxon test and Friedman test to evaluate the effect of the radiolucent material on the amount of bone visible. Differences were considered significant if p < 0.5. In every specimen p was <0.5. The amount of bone visible was significantly higher with the radiolucent frame compared to the radiopaque frame. Based on the results of this study, the use of radiolucent materials can be a valuable option for external fixation, in order to decrease the radiographic interference of the frame, allowing better assessment of fracture reduction and bone healing on postoperative radiographs.

Palmar plating of distal radius fractures : 3-year follow-up with titanium and PEEK plates give similar outcomes

A variety of different plate designs and materials are available to treat distal radius fractures. This study evaluates clinical results with a carbon fibre- reinforced (CFR)-polyether ether ketone (PEEK) plate in comparison to a standard titanium plate. Thirty-one distal radius fractures were included in this randomised controlled trial. Five fractures were classified as type A, 6 as type B and 20 as type C, in accordance with the AO classification. Patients were randomly allocated into two groups : 15 patients for titanium palmar plating (TPP) and 16 patients for PEEK palmar plating (PPP). Follow-up examinations were set at 2 weeks, 6 weeks, 3 months, 6 months and 3 years postop. In terms of wrist range of motion, radiological evaluation (alignment and fracture healing), DASH score (Disabilities of Arm, Shoulder and Hand), and VAS (visual analogue scale), no statistically significant differences were detected between the two groups, at all follow-up intervals. PEEK palmar plating and titanium plates give equivalent clinical and radiological outcomes up to 3 years follow-up.

Carbon fibre reinforced PEEK versus traditional metallic implants for orthopaedic trauma surgery: A systematic review

INTRODUCTION

There is no literature review comparing outcomes of fixation using carbon-fibre-reinforced polyetheretherketone (CFR PEEK) compared to metal implants used in orthopaedic extremity trauma surgery. A systematic review was performed to compare CFR PEEK to metal implants for clinically-important fracture outcomes.

METHODS

A search of the online databases of PubMed/Medline, EMBASE and Cochrane Database was conducted. A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A meta-analyses was performed for functional outcomes in proximal humerus fractures converting the score differences to standard mean difference units. GRADE approach was used to determine the level of certainty of the estimates.

RESULTS

Two prospective randomised controlled trials and seven comparative observational studies with a total of 431 patients were included. Of the nine studies included, four compared the use of CFR PEEK against metal plates in proximal humerus fractures. Aggregated functional scores across the proximal humerus studies, there was a small signal of better improvement with CFR PEEK (SMD 0.22, 95% CI -0.03 to 0.47, p = 0.08, low certainty). Greater odds of adverse events occurred in the metal group (OR 2.34, 95% CI 0.73 to 7.55, p = 0.15, low certainty).

CONCLUSIONS

Low to very low certainty evidence suggests a small improvement in functional recovery with CFR PEEK in proximal humerus fractures. This may be mediated through a small reduction in major adverse events related to fracture healing and stability. There is currently insufficient evidence to support the widespread use of CFR PEEK implants in fracture fixation.

LEVEL OF EVIDENCE

Level IV.

Evolution of materials for implants in metastatic spine disease till date - Have we found an ideal material?

"Metastatic Spine Disease" (MSD) often requires surgical intervention and instrumentation with spinal implants. Ti6Al4V is widely used in metastatic spine tumor surgery (MSTS) and is the current implant material of choice due to improved biocompatibility, mechanical properties, and compatibility with imaging modalities compared to stainless steel. However, it is still not the ideal implant material due to the following issues. Ti6Al4V implants cause stress-shielding as their Young's modulus (110 gigapascal [GPa]) is higher than cortical bone (17-21 GPa). Ti6Al4V also generates artifacts on CT and MRI, which interfere with the process of postoperative radiotherapy (RT), including treatment planning and delivery. Similarly, charged particle therapy is hindered in the presence of Ti6Al4V. In addition, artifacts on CT and MRI may result in delayed recognition of tumor recurrence and postoperative complications. In comparison, polyether-ether-ketone (PEEK) is a promising alternative. PEEK has a low Young's modulus (3.6 GPa), which results in optimal load-sharing and produces minimal artifacts on imaging with less hinderance on postoperative RT. However, PEEK is bioinert and unable to provide sufficient stability in the immediate postoperative period. This issue may possibly be mitigated by combining PEEK with other materials to form composites or through surface modification, although further research is required in these areas. With the increasing incidence of MSD, it is an opportune time for the development of spinal implants that possess all the ideal material properties for use in MSTS. Our review will explore whether there is a current ideal implant material, available alternatives and whether these require further investigation.

Can Polyether Ether Ketone Dethrone Titanium as the Choice Implant Material for Metastatic Spine Tumor Surgery?

Instrumentation during metastatic spine tumor surgery (MSTS) provides stability to the spinal column in patients with pathologic fracture or iatrogenic instability produced while undergoing extensive decompression. Titanium is the current implant material of choice in MSTS. However, it hinders radiotherapy planning and generates artifacts, with magnetic resonance imaging and computed tomography scans used for postoperative evaluation of tumor recurrence and/or complications. The high modulus of elasticity of titanium (110 GPa) results in stress shielding, which may lead to construct failure at the bone-implant interface. Polyether ether ketone (PEEK), a thermoplastic polymer, is an emerging alternative to titanium for use in MSTS. The modulus of elasticity of PEEK (3.6 GPa) is close to that of cortical bone (17-21 GPa), resulting in minimal stress shielding. Its radiolucent and nonmetallic properties cause minimal interference with magnetic resonance imaging and computed tomography scans. PEEK also causes low-dose perturbation for radiotherapy planning. However, PEEK has reduced bioactivity with bone and lacks sufficient rigidity to be used as rods in MSTS. The reduced bioactivity of PEEK may be addressed by 1) surface modification (introducing porosity or bioactive coating with hydroxyapatite [HA] or titanium) and 2) forming composites with HA/titanium. The mechanical properties of PEEK may be improved by forming composites with HA or carbon fiber. Despite these modifications, all PEEK and PEEK-based implants are difficult to handle and contour intraoperatively. Our review provides a comprehensive overview of PEEK and modified PEEK implants, with a description of their properties and limitations, potentially serving as a basis for their future development and use in MSTS.

Bilateral Atypical Femur Fractures Complicated by Carbon Fiber Cephalomedullary Nail Fracture: A Case Report

CASE

A 69-year-old woman with a history of breast cancer, on long-term antiresorptive medications, was treated with carbon fiber cephalomedullary nails for bilateral atypical femur fractures. Her thigh pain was presumed to be from metastatic lesions and was treated with radiation without standard imaging. The index procedure was complicated by a left nail fracture. The patient underwent exchange cephalomedullary nail fixation with plate augmentation. At 1 year, the patient was asymptomatic with radiographs demonstrating healing.

CONCLUSION

This case highlights the importance of appropriate imaging in all patients with thigh pain on antiresorptive therapy and features an uncommon complication of carbon fiber cephalomedullary nail fixation.

Volar PEEK plate for distal radius fracture: analysis of adverse events

BACKGROUND

The aim of the present retrospective study was to evaluate complications following carbon-fiber-reinforced polyetheretherketon (CFR-PEEK) volar plating in distal radius fracture in a large cohort of patients. As an alternative to conventional metallic devices, CFR-PEEK plates have been introduced over the last few years.

METHODS

We performed a retrospective study including all patients who were treated for distal radius fracture using a volar fixed-angle plate DiPHOS-RM (Lima Corporate, Udine, Italy). All CFR-PEEK plates implanted were reviewed between May 2012 and December 2017. Plate removal, second surgery and adverse events were collected by reviewing medical records. A total of 110 patients were included with a mean follow-up of 4 years.

RESULTS

Adverse side effects were observed in 9 cases (8%), developed during or after treatment. The most frequent complication was represented by intraoperative plate rupture (4%). Infection was reported in one case.

DISCUSSION

The rate of complications of PEEK volar plates seems to be similar to those occurring with plates of different materials. Advantages of PEEK plates are the absence of the cold-welding phenomenon and the absence of exuberant bone callus on the plate, ensuring an easy hardware removal. Intraoperative rupture remains the main complication correlated with PEEK material. These complications can be reduced with an accurate surgical technique, especially at the beginning of the learning curve.

LEVEL OF EVIDENCE

Therapeutic IV.

Carbon/PEEK nails: a case-control study of 22 cases

BACKGROUND

Interest around carbon/PEEK plates and nails has been raising. The elastic modulus close to the bone, the high load-carrying capacity and radiolucency make CFR/PEEK materials a potential breakthrough. In the literature, there are abundant data about CFR/PEEK plates in the treatment of proximal humerus, distal radius and distal fibula fractures. In patients affected by bone metastasis, CFR/PEEK nails were proved effective and safe with 12 months of follow-up. Very little is known about performances of CFR/PEEK nails in patients affected by other pathologies.

PURPOSES

The aim of the study was to evaluate safety and efficacy of CFR/PEEK nails in the treatment of various pathological conditions. It was also investigated whatever radiolucency of this nails could lead to a more objective evaluation of bone callus or disease site.

PATIENTS AND METHODS

In the study group were included 20 patients (22 bone segments) who underwent CFR/PEEK nail implantation (eight humerus, one tibia, nine femur and four knee arthrodesis). They were affected by pathological fractures, and in four cases, they required an arthrodesis of the knee. They were retrospectively evaluated considering nail failures and bone callus or disease progression (RUSH scores). Mean follow-up time was 11 months (min 6.8-max 20.3). In the control group were included patients treated with titanium nails in the same institution for the same pathologies. An interclass correlation coefficient (ICC) analysis was performed in both groups considering RUSH scores by two expert surgeon from two institution to assess whether radiolucency could lead to a more objective evaluation of disease or bone callus site.

RESULTS

The ICC of mean values between RUSH scores was 0.882 (IC 95%: 0.702-0.953) in the CFR/PEEK group, while it was 0.778 (IC 95%: 0.41-0.91) in the titanium group. Observers' evaluation showed a significantly higher obscuration by titanium nails than by CFR/PEEK nails. No osteosynthesis failures were reported in both groups.

CONCLUSIONS

Our results confirm the safety of CFR/PEEK nails in the short-medium term. The radiolucency of these materials led our observers to perform more objective evaluations of bone callus formation or disease progression compared to the titanium group given the higher ICC.

LEVEL OF EVIDENCE

III Case-control therapeutic study.

The use of Carbon-Peek volar plate after distal radius osteotomy for Kienbock's Disease in a volleyball athlete: a case report

Kienbock’s Disease, or lunatomalacia, has uncertain etiopathogenesis, it is more common in male from 20 to 45-year-old. The Lichtman’s classification is the most used by authors and it divides Kienbock’s Disease in 4 stages according to radiographic parameters. In early stages could be performed a conservative treatment, but failure rate is high; various surgical techniques are available in case of failure or higher stages. We report a case of a 26-year-old female volleyball player affected by stage I Kienbock’s Disease who underwent distal radius osteotomy core decompression synthesized with Carbon-Peek plate fixation. Follow-up was performed with clinical evaluation (ROM analysis, VAS score, Quick Dash Score), wrist radiographs and wrist MRI. (www.actabiomedica.it)

PEEK radiolucent plate for distal radius fractures: multicentre clinical results at 12 months follow up

INTRODUCTION

Open reduction and internal fixation (ORIF) with plate and screws represents the recommended treatment for unstable intra-articular distal radius fractures. Although significant progresses in surgical technique have been made, anatomical reconstruction of radio-carpal articular surface still represent a difficult task, especially in multifragmentary fractures. Available PEEK reinforced-carbon fiber composite radiolucent devices allow both an easier and more careful assessment of intra-operative reduction of the articular surface of distal radius and prompt correction of any residual step deformity.

MATERIALS AND METHODS

We retrospectively reviewed clinical and radiological multicentre results of 71 consecutive AO B and C fracture pattern of distal radius treated using the same PEEK reinforced-carbon fiber composite radiolucent plate.

RESULTS

Three patients lost at final follow up and 4 cases with incomplete radiological documentations were excluded from the study. 64 patients (38 females, 26 males) were available and formed the basis of this report. Fracture types included 9 patients with 23-B, 13 patients 23-B2,15 patients with 23-B3,10 patients with 23-C1, 7 patients with 23-C2 and 10 patients with 23-C3. Mean Modified Mayo wrist Score was on average 38.11 (SD 10.1; range 24-75, 95%CI 34.7-41.4), 67.22 (SD 9.6, range 50-90, 95%CI 64-70.4), 90.54 (SD 6.3, range 75-100, 95%CI 88.4-92.6) at one, two and twelve months of follow-up, respectively. A statistically significant difference was found between mean scores at different follow-up periods (p = 0.001). We noted 1 case of distal screw fixation aseptic loosening at 5 months post surgical intervention.

CONCLUSIONS

PEEK reinforced-carbon fiber composite radiolucent plate represents a useful device for treatment of complex distal radius fractures in the adult population. It possesses unique biomechanical properties and allows for an easier anatomical reduction during surgical intervention.

Carbon-fiber reinforced intramedullary nailing in musculoskeletal tumor surgery: a national multicentric experience of the Italian Orthopaedic Society (SIOT) Bone Metastasis Study Group

INTRODUCTION

Carbon fiber reinforced (CFR) implants have been proposed for the treatment of fractures or impending fractures of the long bones in the oncology patient. Aim of this study is to present the largest cohort of oncology patients operated by CFR nailing by the Italian Orthopaedic Society (SIOT) Bone Metastasis Study Group.

METHODS

53 adult oncology patients were operated on with a CFR-PEEK nail. All the data from adjuvants therapies were collected. Bone callus formation, response to radiotherapy, relapse or progression of the osteolysis were recorded. Hardware survival and failure, breakage and need for implant revision were also analysed.

RESULTS

Anatomical implantation of nails include humerus (n = 35), femur (n =11) and tibia (n = 7). The most frequent tumors affecting the bone were myeloma (n = 13), breast (n = 11), lung (n = 8), and renal cell cancer (n = 7). Acrylic cement reinforcement was used in 2 patients. One patient was subjected to electrochemotherapy after nail insertion. Intraoperative and early postoperative complications occurred in 13.2% and 7.54% of patients respectively. Eight patients had local progression and one developed a stress fracture proximally to the distal static screw. Radiographic union occurred in 14 patients; one screw loosening was recorded.

DISCUSSION

There is currently a lack of solid evidence on the clinical use of CFR nails in oncologic patients. This is the first and largest study of CFR nailing, with the longest available follow up.

CONCLUSIONS

Implant related complications and surgery-related morbidity should be taken into account in the decision-making process for the surgical management of these patients. These data can improve the surgeon-patient communication and guide further studies on patients' survival and complications with respect to surgery.

Comparison between Carbon-Peek volar locking plates and titanium volar locking plates in the treatment of distal radius fractures

INTRODUCTION

Unstable intra articular fractures of distal radius are frequently being managed with open reduction and internal fixation. Volar locking plate based on polyetheretherketon (PEEK) polymer has developed lately as an alternative to conventional metallic devices. The advantage of this kind of plates include the lack of metal allergies, radiolucency, low artefacts on MRI or imaging scans and the high resistance associated to loading forces. The aim of this study was to evaluate the clinical and radiological results using a new Carbon-PEEK volar locking plate compared with titanium volar locking plates for the treatment of distal radius fractures.

METHODS AND MATERIAL

Thirty patients were included in this study. They all underwent traumatic intra-articular distal radius fractures and were surgically treated with volar locking plates. The patients were randomly divided in two groups: In Group A (15 patients) the fracture was stabilized with a CarboFix volar locking plate whereas in group B (15 patients) with an Acu-Lock Volar Distal Radius Plate. Range of motion (ROM), grip strength, Disabilities of the Arm, Shoulder and Hand (DASH) score and X-rays were evaluated. The mean follow up was 12 months.

RESULTS

Analysis of Wrist ROM revealed that there was no statistical significant difference (p > 0.05) in regards to extension, flexion, ulnar deviation, radial deviation, supination and pronation comparing to the unaffected arm and between Group A and Group B. The mean score on the DASH was 15.3 in Group A and 13.2 in Group B (p > 0.05). Patients were able to return to their normal activities of daily living at an average of 4 weeks post-op in both Groups. Overall, the mean VAS score was 3.6 There were no statistically significant differences (p > 0.05) on X-Rays examination between two Groups in regards to alignment and fracture healing.

CONCLUSIONS

Volar locking plates represent the most common procedure for the treatment of displaced distal radius fractures. In our series Carbon-peek volar locking plates seems to be analogue to titanium volar locking plates in terms of radiographic parameters and functional outcome.

Carbon fiber intramedullary nails reduce artifact in postoperative advanced imaging

OBJECTIVE

This study assessed whether radiolucent carbon fiber reinforced-polyetheretherketone (CFR-PEEK) intramedullary nails decreased hardware artifact on magnetic resonance imaging (MRI) and computed tomography (CT) in vitro and in an oncologic patient population.

MATERIALS AND METHODS

In vitro and clinical evaluations were done. A qualitative assessment of metal artifact was performed using CFR-PEEK and titanium nail MRI phantoms. Eight patients with a femoral or tibial prophylactic CFR-PEEK nail were retrospectively identified. All patients had postoperative surveillance imaging by MRI, CT, and were followed for a median 20 months (range, 12-28 months). CFR-PEEK images were compared to images from a comparative group of patients with titanium femoral intramedullary nails who had a postoperative MRI or CT. A musculoskeletal-trained radiologist graded visualization of the cortex, corticomedullary junction, and bone-muscle interface, on T1-weighted (T1W), STIR, and contrast-enhanced T1-weighted fat-saturated (T1W FS) sequences of both groups with a five-point scale, performing independent reviews 4 months apart. Statistical analysis used the Wilcoxon rank-sum test and a weighted kappa.

RESULTS

Substantially less MRI signal loss occurred in the CFR-PEEK phantom than in the titanium phantom simulation, particularly as the angle increased with respect to direction of the static magnetic field. CFR-PEEK nails had less MRI artifact than titanium nails on scored T1W, STIR, and contrast-enhanced T1W FS MRI sequences (p ≤ 0.03). The mean weighted kappa was 0.64, showing excellent intraobserver reliability between readings.

CONCLUSIONS

CFR-PEEK intramedullary nail fixation is a superior alternative to minimize implant artifact on MRI or CT imaging for patients requiring long bone fixation.

A new volar plate made of carbon-fiber-reinforced polyetheretherketon for distal radius fracture: analysis of 40 cases

BACKGROUND

Implants based on the polyetheretherketon (PEEK) polymer have been developed in the last decade as an alternative to conventional metallic devices. PEEK devices may provide several advantages over the use of conventional orthopedic materials, including the lack of metal allergies, radiolucency, low artifacts on magnetic resonance imaging scans and the possibility of tailoring mechanical properties. The purpose of this study was to evaluate the clinical results at 12-month follow-up using a new plate made of carbon-fiber-reinforced polyetheretherketon for the treatment of distal radius fractures.

MATERIALS AND METHODS

We included 40 consecutive fractures of AO types B and C that remained displaced after an initial attempt at reduction. The fractures were classified according to the AO classification: 21 fractures were type C1, 9 were type C2, 2 were type C3, 2 were type B1 and 6 were type B2.

RESULTS

At a 12-month follow-up no cases of hardware breakage or loss of the surgically achieved fracture reduction were documented. All fractures healed, and radiographic union was observed at an average of 6 weeks. The final Disabilities of Arm, Shoulder and Hand score was 6.0 points. The average grip strength, expressed as a percentage of the contralateral limb, was 92 %. Hardware removal was performed only in one case, for the occurrence of extensor tenosynovitis.

CONCLUSION

At early follow-up this device showed good clinical results and allowed maintenance of reduction in complex, AO fractures.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

The outcomes of navigation-assisted bone tumour surgery: minimum three-year follow-up

We evaluated the oncological and functional outcome of 18 patients, whose malignant bone tumours were excised with the assistance of navigation, and who were followed up for more than three years. There were 11 men and seven women, with a mean age of 31.8 years (10 to 57). There were ten operations on the pelvic ring and eight joint-preserving limb salvage procedures. The resection margins were free of tumour in all specimens. The tumours, which were stage IIB in all patients, included osteosarcoma, high-grade chondrosarcoma, Ewing's sarcoma, malignant fibrous histiocytoma of bone, and adamantinoma. The overall three-year survival rate of the 18 patients was 88.9% (95% confidence interval (CI) 75.4 to 100). The three-year survival rate of the patients with pelvic malignancy was 80.0% (95% CI 55.3 to 100), and of the patients with metaphyseal malignancy was 100%. The event-free survival was 66.7% (95% CI 44.9 to 88.5). Local recurrence occurred in two patients, both of whom had a pelvic malignancy. The mean Musculoskeletal Tumor Society functional score was 26.9 points at a mean follow-up of 48.2 months (22 to 79). We suggest that navigation can be helpful during surgery for musculoskeletal tumours; it can maximise the accuracy of resection and minimise the unnecessary sacrifice of normal tissue by providing precise intra-operative three-dimensional radiological information.

Potential use of computer navigation in the treatment of primary benign and malignant tumors in children

The treatment of benign and malignant primary bone tumors has progressed over time from relatively simple practice to complex resection and reconstruction techniques. Recently, computer-assisted orthopaedic surgery (CAOS) has been used to assist surgeons to enhance surgical precision in order to achieve these goals. Initially, software developed for CT-based spinal applications was used to perform simple intraoperative point localization. With advances in technique and software design, oncology surgeons have now performed joint sparing complex multiplanar osteotomies using combined CT and MRI image data with precision and accuracy. The purpose of this paper is to provide a review of the clinical progress to date, the different types of navigation available, methods for error management, and limitations of CAOS in the treatment of pediatric benign and malignant primary bone tumors.

Application of carbon fibers to biomaterials: a new era of nano-level control of carbon fibers after 30-years of development

Carbon fibers are state-of-the-art materials with properties that include being light weight, high strength, and chemically stable, and are applied in various fields including aeronautical science and space science. Investigation of applications of carbon fibers to biomaterials was started 30 or more years ago, and various products have been developed. Because the latest technological progress has realized nano-level control of carbon fibers, applications to biomaterials have also progressed to the age of nano-size. Carbon fibers with diameters in the nano-scale (carbon nanofibers) dramatically improve the functions of conventional biomaterials and make the development of new composite materials possible. Carbon nanofibers also open possibilities for new applications in regenerative medicine and cancer treatment. The first three-dimensional constructions with carbon nanofibers have been realized, and it has been found that the materials could be used as excellent scaffolding for bone tissue regeneration. In this critical review, we summarize the history of carbon fiber application to the biomaterials and describe future perspectives in the new age of nano-level control of carbon fibers (122 references).

Direct application of MR images to computer-assisted bone tumor surgery

BACKGROUND

We describe a method for the direct application of MR images to navigation-assisted bone tumor surgery as an alternative to CT-MRI fusion.

METHOD

Six patients with an orthopedic malignancy were employed for this method during navigation-assisted tumor resection. Tumor types included osteosarcoma (4), high-grade chondrosarcoma (1), and adamantinoma (1). Mean patient age was 25.3 years (range 18-52 years). Mean duration of follow-up was 25.8 months (range 18-32 months). Resorbable pin placement and rapid 3-dimensional spoiled gradient echo sequences made the direct application of MR images to computer-assisted bone tumor surgery without CT-MR image fusion possible. A paired-point registration technique was employed for patient-image registration in all patients.

RESULTS

It took 20 min on average to set up the navigation (range 15-25 min). The mean registration error was 0.98 mm (range 0.4-1.7 mm). On histologic examination, distances from tumors to resection margins were in accord with preoperative plans. No patient had a local recurrence or distant metastasis at the last follow-up.

CONCLUSION

Direct patient-to-MRI registration is a very useful method for bone tumor surgery, permitting the application of MR images to intraoperative visualization without any additional costs or exposure of the patient to radiation from the preoperative CT scan.

The long-term mechanical integrity of non-reinforced PEEK-OPTIMA polymer for demanding spinal applications: experimental and finite-element analysis

Polyetheretherketone (PEEK) is a novel polymer with potential advantages for its use in demanding orthopaedic applications (e.g. intervertebral cages). However, the influence of a physiological environment on the mechanical stability of PEEK has not been reported. Furthermore, the suitability of the polymer for use in highly stressed spinal implants such as intervertebral cages has not been investigated. Therefore, a combined experimental and analytical study was performed to address these open questions. A quasi-static mechanical compression test was performed to compare the initial mechanical properties of PEEK-OPTIMA polymer in a dry, room-temperature and in an aqueous, 37 degrees C environment (n=10 per group). The creep behaviour of cylindrical PEEK polymer specimens (n=6) was measured in a simulated physiological environment at an applied stress level of 10 MPa for a loading duration of 2000 hours (12 weeks). To compare the biomechanical performance of different intervertebral cage types made from PEEK and titanium under complex loading conditions, a three-dimensional finite element model of a functional spinal unit was created. The elastic modulus of PEEK polymer specimens in a physiological environment was 1.8% lower than that of specimens tested at dry, room temperature conditions (P<0.001). The results from the creep test showed an average creep strain of less than 0.1% after 2000 hours of loading. The finite element analysis demonstrated high strain and stress concentrations at the bone/implant interface, emphasizing the importance of cage geometry for load distribution. The stress and strain maxima in the implants were well below the material strength limits of PEEK. In summary, the experimental results verified the mechanical stability of the PEEK-OPTIMA polymer in a simulated physiological environment, and over extended loading periods. Finite element analysis supported the use of PEEK-OPTIMA for load-bearing intervertebral implants.