Patient-specific implants made of 3D printed bioresorbable polymers at the point-of-care: material, technology, and scope of surgical application.

BACKGROUND: Bioresorbable patient-specific additive-manufactured bone grafts, meshes, and plates are emerging as a promising alternative that can overcome the challenges associated with conventional off-the-shelf implants. The fabrication of patient-specific implants (PSIs) directly at the point-of-care (POC), such as hospitals, clinics, and surgical centers, allows for more flexible, faster, and more efficient processes, reducing the need for outsourcing to external manufacturers. We want to emphasize the potential advantages of producing bioresorbable polymer implants for cranio-maxillofacial surgery at the POC by highlighting its surgical applications, benefits, and limitations. METHODS: This study describes the workflow of designing and fabricating degradable polymeric PSIs using three-dimensional (3D) printing technology. The cortical bone was segmented from the patient's computed tomography data using Materialise Mimics software, and the PSIs were designed created using Geomagic Freeform and nTopology software. The implants were finally printed via Arburg Plastic Freeforming (APF) of medical-grade poly (L-lactide-co-D, L-lactide) with 30% ß-tricalcium phosphate and evaluated for fit. RESULTS: 3D printed implants using APF technology showed surfaces with highly uniform and well-connected droplets with minimal gap formation between the printed paths. For the plates and meshes, a wall thickness down to 0.8 mm could be achieved. In this study, we successfully printed plates for osteosynthesis, implants for orbital floor fractures, meshes for alveolar bone regeneration, and bone scaffolds with interconnected channels. CONCLUSIONS: This study shows the feasibility of using 3D printing to create degradable polymeric PSIs seamlessly integrated into virtual surgical planning workflows. Implementing POC 3D printing of biodegradable PSI can potentially improve therapeutic outcomes, but regulatory compliance must be addressed.

In-house 3D-printed custom splints for non-operative treatment of distal radial fractures: a randomized controlled trial.

We compared patient satisfaction and clinical effectiveness of 3D-printed splints made of photopolymer resin to conventional fibre glass casts in treating distal radial fractures. A total of 39 patients with minimally displaced distal radius fractures were included and randomized. Of them, 20 were immobilized in a fibre glass cast and 19 in a 3D-printed forearm splint. The 3D-printed splints were custom-designed based on forearm surface scanning with a handheld device and printed in-house using digital light processing printing technology. Patient satisfaction and clinical effectiveness were assessed with questionnaires 1 and 6 weeks after the initiation of immobilization. Fracture healing, pain, range of motion, grip strength and the DASH and PRWE scores were assessed up to 1-year follow-up. 3D-printed splints proved to be equally well tolerated by the patients and equally clinically effective as conventional fibre glass casts although there was a higher rate of minor complications. 3D-printed splints present a safe alternative, especially in young, active patients, for non-operative treatment of distal radial fractures.Level of evidence: I.

Extension osteotomy of the metacarpal I and ligamentoplasty of the trapeziometacarpal joint for the treatment of early-stage osteoarthritis and instability of the trapeziometacarpal joint.

Osteoarthritis (OA) is a common disease of the first carpo-metacarpal (CMC I) joint. Biomechanical factors promoting OA are the shape of the CMC I-joint, being a biconcave-convex saddle joint with high mobility and the increased instability caused by joint space narrowing, ligamentous laxity, and direction of force transmission of the abductor pollicis longus (APL) tendon during adduction. The closing wedge osteotomy of the base of the first metacarpal is joint preserving treatment option. We combine this closing wedge osteotomy with a ligamentoplasty to stabilize the joint. In this manuscript, we provide a detailed description of the indication, discuss biomechanical aspects and the surgical technique in detail.

Artificial intelligence in patient-specific hand surgery: a scoping review of literature.

PURPOSE: The implementation of artificial intelligence in hand surgery and rehabilitation is gaining popularity. The purpose of this scoping review was to give an overview of implementations of artificial intelligence in hand surgery and rehabilitation and their current significance in clinical practice. METHODS: A systematic literature search of the MEDLINE/PubMed and Cochrane Collaboration libraries was conducted. The review was conducted according to the framework outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews. A narrative summary of the papers is presented to give an orienting overview of this rapidly evolving topic. RESULTS: Primary search yielded 435 articles. After application of the inclusion/exclusion criteria and addition of supplementary search, 235 articles were included in the final review. In order to facilitate navigation through this heterogenous field, the articles were clustered into four groups of thematically related publications. The most common applications of artificial intelligence in hand surgery and rehabilitation target automated image analysis of anatomic structures, fracture detection and localization and automated screening for other hand and wrist pathologies such as carpal tunnel syndrome, rheumatoid arthritis or osteoporosis. Compared to other medical subspecialties the number of applications in hand surgery is still small. CONCLUSION: Although various promising applications of artificial intelligence in hand surgery and rehabilitation show strong performances, their implementation mostly takes place within the context of experimental studies. Therefore, their use in daily clinical routine is still limited.

Distance mapping in three-dimensional virtual surgical planning in hand, wrist and forearm surgery: a tool to avoid mistakes.

PURPOSE: Three-dimensional planning in corrective surgeries in the hand and wrist has become popular throughout the last 20 years. Imaging technologies and software have improved since their first description in the late 1980s. New imaging technologies, such as distance mapping (DM), improve the safety of virtual surgical planning (VSP) and help to avoid mistakes. We describe the effective use of DM in two representative and frequently performed surgical interventions (radius malunion and scaphoid pseudoarthrosis). METHODS: We simulated surgical intervention in both cases using DM. Joint spaces were quantitatively and qualitatively displayed in a colour-coded fashion, which allowed the estimation of cartilage thickness and joint space congruency. These parameters are presented in the virtual surgical planning pre- and postoperatively as well as in the actual situation in our cases. RESULTS: DM had a high impact on the VSP, especially in radius corrective osteotomy, where we changed the surgical plan due to the visualization of the planned postoperative situation. The actual postoperative situation was also documented using DM, which allowed for comparison of the VSP and the achieved postoperative situation. Both patients were successfully treated, and bone healing and clinical improvement were achieved. CONCLUSION: The use of colour-coded static or dynamic distance mapping is useful for virtual surgical planning of corrective osteotomies of the hand, wrist and forearm. It also allows confirmation of the correct patient treatment and assessment of the follow-up radiological documentation.

Radiological, Clinical, and Functional Outcomes of Combined Dorsal and Volar Locking Plate Osteosynthesis for Complex Distal Radius Fractures.

PURPOSE: The purpose of this study was to assess the short- to mid-term radiologic, clinical, and functional outcomes of patients treated with combined dorsal and volar locking plating for internal fixation of complex, comminuted, intra-articular, distal radius fractures. METHODS: We performed a retrospective review of 34 patients treated with combined dorsal and volar locking plates for the internal fixation of complex, comminuted, intra-articular distal radius fractures. Radiographic and clinical parameters were recorded at a mean of 48 months after surgery. Activities of daily living and quality of life were assessed by the Disabilities of the Arm, Shoulder, and Hand and Patient-Rated Wrist Evaluation questionnaires. RESULTS: Compared with the contralateral wrist, the treated wrist regained 73% of flexion, 81% of extension, 86% of ulnar deviation, 90% of radial deviation, 98% of pronation, 99% of supination, and 93% of grip strength. Mean Disabilities of the Arm, Shoulder, and Hand and Patient-Rated Wrist Evaluation scores were 11 (range, 0-78) and 11 (range, 0-77), respectively. Radial height and radial inclination were restored anatomically in 24% and 41% of patients, respectively, while volar tilt and ulnar variance were restored in 68% of patients. CONCLUSION: The overall functional and radiologic outcome of patients with comminuted intra-articular complex distal radius fractures treated with the combined dorsovolar plate osteosynthesis was good to excellent. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Cold ablation robot-guided laser osteotomy in hand, wrist and forearm surgery-A feasibility study.

INTRODUCTION: Traditional bone surgery using saws and chisels is associated with direct contact of instruments with the bone causing friction, heat and pressure and hence, damaging the bone and the surrounding soft tissues. METHOD: Cold ablation laser osteotomy offers new possibilities to perform corrective osteotomies in the field of bone surgery. We introduce the technology of navigated cold ablation robot-guided laser osteotomy, present potential applications, and preliminary pre-clinical cadaver test results in the field of hand-, wrist- and forearm surgery. RESULTS: The cadaver tests showed first promising results for corrections in all planes and axes using different cutting patterns. CONCLUSION: Cold ablation laser osteotomy seems to be a feasible new method to perform osteotomies in the field of hand-, wrist- and forearm surgery. Primary osseous stability could be achieved using various cutting patterns which could lead to reduction of the amount of hardware required for osteosynthesis. Further tests are required to proof the latter and precision.

Dorsal Plate Osteosynthesis in Simple and Complex Fractures of the Distal Radius: A Radiological Analysis of 166 Cases.

Background To report the radiologic outcome and rate of complications of open reduction and internal fixation (ORIF) using a dorsal plate fixation of simple and complex distal radius fractures in adult patients. Methods Patients treated with dorsal ORIF of simple and complex distal radius fractures between December 2008 and April 2013 were included in this single-center retrospective study. Type of fracture, radiographic measurements, and complications were documented. Results One-hundred and sixty-six patients/fractures were included. Restoration of radial inclination (22° ± 3°) was achieved in 38%. Radial height (14 ± 1 mm) was least likely to be restored to normal values postoperative in 25%. Normal ulnar variance (0.7 ± 1.5 mm) could be observed in 60% and adequate volar tilt (11° ± 5°) was achieved in 50% at final follow-up. We observed one loss of reduction in an AO type C2 fracture and a total of 15 nonimplant-related minor clinical complications. Conclusion Our radiographic findings after dorsal plating are comparable to those published on volar plating. The changes in radial height and volar tilt could be attributed to projection-related differences in the radiographs and did not signify a loss of reduction in all cases. Clinical Relevance Dorsal plating of distal radius fractures is safe and remains an important approach in the treatment of complex distal radius fractures. Complications in our study were even less compared to those reported in the literature. Type of Study/Level of Evidence This is a Type IV study. Level of Experience of Surgeons The level of experience of surgeons is III-V.

Quantitative Assessment of Point-of-Care 3D-Printed Patient-Specific Polyetheretherketone (PEEK) Cranial Implants.

Recent advancements in medical imaging, virtual surgical planning (VSP), and three-dimensional (3D) printing have potentially changed how today's craniomaxillofacial surgeons use patient information for customized treatments. Over the years, polyetheretherketone (PEEK) has emerged as the biomaterial of choice to reconstruct craniofacial defects. With advancements in additive manufacturing (AM) systems, prospects for the point-of-care (POC) 3D printing of PEEK patient-specific implants (PSIs) have emerged. Consequently, investigating the clinical reliability of POC-manufactured PEEK implants has become a necessary endeavor. Therefore, this paper aims to provide a quantitative assessment of POC-manufactured, 3D-printed PEEK PSIs for cranial reconstruction through characterization of the geometrical, morphological, and biomechanical aspects of the in-hospital 3D-printed PEEK cranial implants. The study results revealed that the printed customized cranial implants had high dimensional accuracy and repeatability, displaying clinically acceptable morphologic similarity concerning fit and contours continuity. From a biomechanical standpoint, it was noticed that the tested implants had variable peak load values with discrete fracture patterns and failed at a mean (SD) peak load of 798.38 ± 211.45 N. In conclusion, the results of this preclinical study are in line with cranial implant expectations; however, specific attributes have scope for further improvements.

A Multi-Criteria Assessment Strategy for 3D Printed Porous Polyetheretherketone (PEEK) Patient-Specific Implants for Orbital Wall Reconstruction.

Pure orbital blowout fractures occur within the confines of the internal orbital wall. Restoration of orbital form and volume is paramount to prevent functional and esthetic impairment. The anatomical peculiarity of the orbit has encouraged surgeons to develop implants with customized features to restore its architecture. This has resulted in worldwide clinical demand for patient-specific implants (PSIs) designed to fit precisely in the patient's unique anatomy. Material extrusion or Fused filament fabrication (FFF) three-dimensional (3D) printing technology has enabled the fabrication of implant-grade polymers such as Polyetheretherketone (PEEK), paving the way for a more sophisticated generation of biomaterials. This study evaluates the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the relevant design, biomechanical, and morphological parameters. The performance of the implants is studied as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predict the high durability of the implants, and the maximum deformation values were under one-tenth of a millimeter (mm) domain in all the implant profile configurations. The circular patterned implant (0.9 mm) had the best performance score. The study demonstrates that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor.

Overview of In-Hospital 3D Printing and Practical Applications in Hand Surgery.

Three-dimensional (3D) printing is spreading in hand surgery. There is an increasing number of practical applications like the training of junior hand surgeons, patient education, preoperative planning, and 3D printing of customized casts, customized surgical guides, implants, and prostheses. Some high-quality studies highlight the value for surgeons, but there is still a lack of high-level evidence for improved clinical endpoints and hence actual impact on the patient's outcome. This article provides an overview over the latest applications of 3D printing in hand surgery and practical experience of implementing them into daily clinical routine.

A Rare Case of Cutaneous Trichophyton verrucosum of the Forearm in a 51-Year-Old Cattle Farmer.

Trichophyton verrucosum is a pathogen causing superficial mycoses in cattle worldwide and is one of the few zoophilic dermatophytes. Farmers and veterinarians are at a higher risk for infection owing to frequent direct animal contact. An increase in cases among humans has been observed in the past few years. We report a rare case of T verrucosum of the forearm in a 51-year-old cattle farmer, who after initial treatment with antibiotics and surgery, and in whom diagnosis was delayed, was finally successfully treated with terbinafine and itraconazole.

In-Hospital 3D Printed Scaphoid Prosthesis Using Medical-Grade Polyetheretherketone (PEEK) Biomaterial.

Recently, three-dimensional (3D) printing has become increasingly popular in the medical sector for the production of anatomical biomodels, surgical guides, and prosthetics. With the availability of low-cost desktop 3D printers and affordable materials, the in-house or point-of-care manufacturing of biomodels and Class II medical devices has gained considerable attention in personalized medicine. Another projected development in medical 3D printing for personalized treatment is the in-house production of patient-specific implants (PSIs) for partial and total bone replacements made of medical-grade material such as polyetheretherketone (PEEK). We present the first in-hospital 3D printed scaphoid prosthesis using medical-grade PEEK with fused filament fabrication (FFF) 3D printing technology.

In-hospital professional production of patient-specific 3D-printed devices for hand and wrist rehabilitation.

The reported use of 3D printing in hand and wrist rehabilitation has been mostly limited to feasibility studies and case series so far. Some of the reasons are the lack of purpose-built scanning applications, complicated digital design software, and lengthy and error-prone printing processes. We propose a multidisciplinary workflow for in-hospital mass production of patient-specific 3D-printed devices for hand and wrist rehabilitation.

[Implant arthroplasty in the metacarpophalangeal and proximal interphalangeal finger joints]. / Übersicht über die Endoprothetik an den Fingergrund- und Mittelgelenken.

BACKGROUND: Osteoarthritic changes in the finger joints are common, especially in the elderly population. Without adequate treatment, these changes can lead to pain, joint deformity, instability or impaired motion. Operative treatment options can be divided into prosthetic joint replacement, joint fusion and denervation. PATIENTS/MATERIAL AND METHOD: During the last decades, various prosthetic implant designs have appeared on the market. This article provides an overview of implant evolution, current implants, clinical results and promising technical novelties. RESULTS: Due to favourable clinical long-term results, low revision rates and low costs, the proven silicone spacer has been the gold standard since the 1960 s. In the index and middle finger, lateral stability is crucial to providing a counter bearing to the thumb for a strong key pinch. Medullary-anchored prostheses and modular surface replacement designs have a higher intrinsic stability and may thus be advantageous in the index and middle finger. These implants show promising clinical medium-term results. CONCLUSION: In the past, technical novelties from big joint replacements could not automatically be translated to the finger joints and other parts of the hand. However, new trends such as customised or 3D-printed prosthetic implants are slowly beginning to gain importance in hand surgery.

[Implant Arthroplasty in the Hand and Wrist]. / Endoprothetik an der Hand und am Handgelenk.

Implant Arthroplasty in the Hand and Wrist Abstract. The first implant arthroplasties were conducted as early as the end of the 19th century. After a few decades, during which surgeons focused on the hip and knee, research on joint arthroplasty of the hand and wrist was intensified. Today, it is possible to implant a prosthesis in nearly every joint of the hand and wrist, giving us an alternative to joint fusion in severe joint destruction. The main advantage of arthroplasty is the preservation of motion. In the metacarpophalangeal and proximal interphalangeal joint every new implant is rivaled by the silicone spacer which has proven its value over decades. Further, no implant in the thumb carpometacarpal joint was able to outmatch the time-tested trapezectomy with LRTI (ligament reconstruction and tendon interposition) due to high implant-loosening rates in the past. In wrist arthroplasty, studies have shown good results concerning pain reduction, function and grip strength. Complication rates however are still higher compared to joint fusion. The results improved with the latest implant designs, yet long-term outcomes, especially for the young, high-demand patients, are missing.

Quality Characteristics and Clinical Relevance of In-House 3D-Printed Customized Polyetheretherketone (PEEK) Implants for Craniofacial Reconstruction.

Additive manufacturing (AM) of patient-specific implants (PSIs) is gradually moving towards in-house or point-of-care (POC) manufacturing. Polyetheretherketone (PEEK) has been used in cranioplasty cases as a reliable alternative to other alloplastic materials. As only a few fused filament fabrication (FFF) printers are suitable for in-house manufacturing, the quality characteristics of the implants fabricated by FFF technology are still under investigated. This paper aimed to investigate PEEK PSIs fabricated in-house for craniofacial reconstruction, discussing the key challenges during the FFF printing process. Two exemplary cases of class III (Group 1) and class IV (Group 2) craniofacial defects were selected for the fabrication of PEEK PSIs. Taguchi's L9 orthogonal array was selected for the following nonthermal printing process parameters, i.e., layer thickness, infill rate, number of shells, and infill pattern, and an assessment of the dimensional accuracy of the fabricated implants was made. The root mean square (RMS) values revealed higher deviations in Group 1 PSIs (0.790 mm) compared to Group 2 PSIs (0.241 mm). Horizontal lines, or the characteristic FFF stair-stepping effect, were more perceptible across the surface of Group 1 PSIs. Although Group 2 PSIs revealed no discoloration, Group 1 PSIs displayed different zones of crystallinity. These results suggest that the dimensional accuracy of PSIs were within the clinically acceptable range; however, attention must be paid towards a requirement of optimum thermal management during the printing process to fabricate implants of uniform crystallinity.

Failure of Osseointegration of a Semiconstrained Finger Prosthesis in a Post-traumatic Metacarpophalangeal Joint Defect: A Case Report.

CASE: Post-traumatic defects of the metacarpophalangeal joint (MCPj) remain challenging for hand surgeons. Restoration of stability and motion are difficult to achieve because of the complex anatomy and kinematics. The Robert Mathys (RM) semiconstrained prosthesis offers good intrinsic stability and mobility and therefore seems suitable. We report on a patient where the RM prosthesis was used for a traumatic destroyed ring finger MCPj reconstruction but failed because of aseptic loosening. We discuss possible reasons in light of the current literature on post-traumatic MCPj arthroplasties and the RM prosthesis in particular. CONCLUSION: The RM proximal interphalangeal prosthesis does not seem suitable for post-traumatic replacement of the MCPj.

Biohackers and Self-Made Problems: Infection of an Implanted RFID/NFC Chip: A Case Report.

CASE: We describe the case of a 26-year-old man with an infected Radio-Frequency-Identification/Near Field Communication (RFID/NFC) chip in the middle finger. The RFID/NFC chip was removed, the soft tissue debrided, and a pan-sensitive staphylococcus aureus was detected by sonication of the RFID/NFC chip. The patient was postoperatively treated with amoxicillin and clavulanic acid (24 hours iv, total 11 days) and an intrinsic plus splint which led to complete recovery. CONCLUSION: Modern body modifications can lead to infections which shouldn't be underestimated. Interdisciplinary treatment is a key to success.