Patient-specific Instrumentation Research Articles

Patient-specific instrumentation in primary total shoulder arthroplasty: a meta-analysis of clinical outcomes.

The introduction of patient-specific instrumentation (PSI) in total shoulder arthroplasty (TSA) has improved implant positioning accuracy. However, whether PSI yields additional clinical benefit compared to standard instrumentation (SI) in the setting of primary TSA (anatomic and reverse) remains unclear. PubMed, Cochrane, Embase, and Google Scholar were queried through August 2024. Inclusion criteria consisted of studies that compared PSI to SI in TSA (anatomic and reverse). Key outcomes analyzed included adverse events, patient-reported outcomes, and discrepancies between planned and achieved implant positioning. Five retrospective studies, three randomized controlled trials, and one prospective study met the inclusion criteria. There was no difference in complications (odds ratio [OR], 1.00; 95% CI, 0.16 to 6.10; P=1.00), reoperation (OR, 1.35; 95% CI, 0.37 to 4.91; P=0.65), American Shoulder and Elbow Surgeons score (mean difference [MD], 1.61; 95% CI, -4.08 to 7.30; P=0.58), Constant-Murley Score (MD, 3.06; 95% CI, -3.68 to 9.81; P=0.37), version error (MD, -0.76; 95% CI, -2.51 to 0.99; P=0.40), and inclination error (MD, -2.89; 95% CI, -5.82 to 0.05; P=0.05) between the two groups. This study found no significant differences in patient-reported outcomes, complication rates, or implant positioning accuracy between PSI and SI in primary TSA. Future randomized controlled trials comparing these two types of instrumentation would be useful to assess whether a benefit exists for PSI in the setting of primary TSA. Level of evidence: III.

Patient-Specific total knee arthroplasty for valgus osteoarthritis results in the use of minimal thickness polyethylene liners in low constraint implants.

Correction of valgus knee deformity during total knee arthroplasty (TKA) can present numerous challenges. This study assessed the ability of a patient-specific knee design to allow easier intraoperative balancing of valgus knees in primary TKA. This study utilized a database consisting of de-identified computed tomography (CT) scans, low constraint knee designs (CR or PS), tibial and femoral implant dimensions, and implanted polyethylene (PE) thickness for all patients who underwent primary TKA with a patient-specific knee design provided by Conformis Inc. (Boston, MA, US). Data were analyzed for knee design, coronal deformity, native posterior and distal femoral offset, and PE thickness. A total of 26,227 cases were included, of which 25% had valgus deformity. In the PS group, the thinnest available PE (6mm) was used for 64% of varus cases and 68% of valgus cases (P = 0.004). There was no difference in the distribution of thin (≤ 8mm) and thick (> 8mm) PE between varus or valgus knees with 0-5 degrees or > 10 degrees of deformity. Knees with varus deformity of 5-10 degrees were more likely to receive a thick PE than knees with valgus deformity of 5-10 degrees. For the CR group, the thinnest available PE (6mm) was used in 77% of varus cases and 76% of valgus cases (P = 0.12). There was no difference in the distribution of thin and thick PE between varus or valgus knees regardless of deformity. Over 99% of CR knees received PE with thicknesses 8mm or less, regardless of degree of preoperative varus or valgus deformity. These results indicate that patient-specific instrumentation in TKA can facilitate valgus deformity correction without requiring increased PE thickness to achieve balancing. Patient-specific knee designs may reduce the difficulty of valgus knee correction while allowing the use of minimal thickness PEs in low constraint TKA implants.

Patient specific implants and instruments in orthopaedic trauma: 3D prints and implants in perlvic and hip fractures

Modern pelvic surgery is essentially influenced by technological innovations. One of the most impressive advances in this field is the integration of 3D printing and the associated possibility for the production of 1:1 models of the pelvic skeleton. Using these models, conventional pelvic implants can preoperatively be more exactly and patient-specifically contoured. The use of this technology has the potential to substantially improve the quality of care and simultaneously to optimize the surgical results. By the use of 3D-printed implants, which are individually adapted to the anatomical conditions of the patient, operations can not only be carried out more quickly and efficiently but also with a greater accuracy and potentially fewer complications. This article presents two instructive cases. Case 1 demonstrates how a proximal femoral fracture with a pre-existing deformity of the femur can be treated with a patient-specific implant. Treatment with conventional intramedullary or extramedullary implants was not possible. Case 2 illustrates the treatment of a pelvic ring fracture and the advantage of 3D printing for the preoperative patient-specific contouring of conventional plate systems.

Learning curve of augmented reality surgical application for reverse shoulder arthroplasty.

Accurate positioning of the glenoid component in reverse total shoulder arthroplasty is important since it reduces prosthesis-related complications. Conventional instrumentation is still the gold standard. However, patient-specific instrumentation using 3-D printed guides, as well as computer-assisted navigation, is gaining more and more importance. Augmented reality has been established to enable the surgeon to have more precision in the positioning and inclination of the glenoid component. A new technique called "NextAR" (©Medacta) supports the surgeon during operation by guidance on bone preparation, instrument navigation, and implant placement, using virtual reality goggles or displays. The aim of this study was to determine a learning curve for reversed total shoulder arthroplasty by a high-volume single shoulder surgeon using the NextAR system. We performed retrospective data analysis of the first 20 cases of one high-volume single shoulder surgeon performing reversed total shoulder arthroplasty using the NextAR system. Parameters such as anesthesia time, surgical time, length of hospital stay, classification of the American Society of Anesthesiologists, body mass index, intraoperative blood loss, and complications were analyzed. We found significant decreases in measures like surgery time (p = 0,001), amount of blood loss during surgery (p = 0,005), and anesthesia time (p = 0,08). A remarkable turning point of blood loss occurs within the fifteenth surgery. A significant reduction of the operation time is shown at the fourteenth operation. Looking at blood loss and operation time together using a standardized cumulative curve, a significant reduction of the cumulative score is found within the fifteenth surgery. Significance was found in surgery time as well as in the amount of blood loss. However, these results may not be generalizable since they depend on further conditions. Future studies could provide information about other outcome parameters and learning curves of several surgeons performing reversed total shoulder arthroplasty with augmented reality applications.

Enabling technology in adult spinal deformity.

Enabling technology in adult spinal deformity.

More Precision, So Greater TKA Longevity? Not Yet: Commentary on an article by M.M. Farhan-Alanie, MRCS, et al.: "The Effects of Computer Navigation and Patient-Specific Instrumentation on Risk of Revision, PROMs, and Mortality Following Primary TKR. An Analysis of National Joint Registry Data".

More Precision, So Greater TKA Longevity? Not Yet: Commentary on an article by M.M. Farhan-Alanie, MRCS, et al.: "The Effects of Computer Navigation and Patient-Specific Instrumentation on Risk of Revision, PROMs, and Mortality Following Primary TKR. An Analysis of National Joint Registry Data".

Effects of femoral de-rotation on lower limb alignment using patient-specific guides with reliance on EOS scan, a retrospective study

The aim of this study is to evaluate the effects of midshaft femoral derotation surgery on the alignment of the lower limbs in the coronal and sagittal planes, as well as its impact on pelvic parameters in patients with significant femoral anteversion or retroversion.A retrospective review was conducted on patients who underwent femoral derotation procedures using a minimally invasive patient-specific external guide system from January 2014 to January 2022 at Macquarie University Hospital. The surgery was done using preoperative 3D modeling and patient-specific external guides. Inclusion criteria comprised patients presenting with hip, knee, or patellofemoral symptoms due to high femoral anteversion who had complete EOS scans performed preoperatively and postoperatively. The EOS imaging system was utilized for accurate assessment and comparative analysis of alignment changes following the femoral derotation.There were 22 limbs from 15 patients with an average age at operation of 30.41 ± 10.14 years (range 16.77–47.50). The average preoperative 3D EOS measurement of the femoral version in anteversion and retroversion groups were 32.84 ± 7.53° and − 22.67 ± 13.32°, respectively. The postoperative femoral version in anteversion and retroversion groups were 13.39 ± 12.90° and 3.67 ± 9.29° having p < 0.001 and p < 0.014, respectively. Paired t-test was employed to calculate statistical values. Other parameters, including Hip-knee-shaft (HKS) angle, knee angle, pelvic tilt, pelvic incidence, mechanical lateral distal femoral angle (mLDFA), and coronal plane alignment of the knee, were not statistically significant differences.This study provides evidence that femoral midshaft derotation surgery using patient-specific instrumentation (PSI) guides is an effective approach for correcting femoral anteversion and retroversion with no significant impact on coronal and sagittal lower limb alignment except femoral neck offset.

Patient-specific instrumentation technology enhances clinical outcomes in total elbow arthroplasty

ObjectiveTo evaluate and compare the outcomes of utilizing patient-specific instrumentation (PSI) technology, which incorporates personalized three-dimensional (3D) preoperative planning and customized 3D printing (3DP) osteotomy guides, against those achieved with traditional instruments in total elbow arthroplasty (TEA).MethodsA retrospective study was conducted to analyze the clinical data of 20 patients diagnosed with elbow arthritis who underwent TEA at the Center for Joint Surgery, The First Hospital Affiliated to Army Medical University, China, between January 2010 and July 2023. Patients were categorized into two groups according to the surgical techniques employed: 9 patients underwent personalized preoperative 3D planning and used customized 3DP osteotomy guides for TEA (3DP group); another 11 patients underwent TEA using traditional instruments and experience-based techniques (traditional group). The intraoperative fluoroscopy frequency, Mayo elbow performance score (MEPS), and Mayo elbow score before and after surgery in both groups were recorded. Additionally, in the 3DP group, changes in the imaging indicators such as the angle between the axis of humerus medullary cavity and the hinge axis of elbow (H-H angle), the angle between the axis of middle ulna medullary cavity and the hinge axis of elbow (MU-H angle), the angle between the axis of proximal ulna medullary cavity and the hinge axis of elbow (PU-H angle) were assessed before and after surgery.ResultsNo significant differences were observed in the baseline characteristics between the 3DP group and the traditional group (P > 0.05). We followed all patients for a period ranging from 12 to 36 months, with an average follow-up duration of 14.8 months. When comparing the two groups, the 3DP group required fewer intraoperative fluoroscopic view (P < 0.01). Postoperatively, the 3DP group showed notable improvements in the H-H angle, MU-H angle, and PU-H angle, all of which were significantly better than those in the traditional group (P < 0.01). Despite these advantages, the postoperative MEPS and Mayo elbow function scores did not differ significantly between the 3DP and traditional groups (P > 0.05).ConclusionCompared with traditional surgical methods, the use of PSI technology with preoperative 3D planning and customized 3DP osteotomy guides can significantly reduce the number of intraoperative fluoroscopies, which enhances both the efficiency and safety of TEA. PSI technology facilitates more accurate angle correction during elbow arthroplasty, ensuring precise osteotomies and effective correction of joint deformities.

Comparison of patient-specific instrumentation (PSI) versus conventional instrumentation (CI) in shoulder arthroplasties: A Meta-Analysis and Systematic Review.

Comparison of patient-specific instrumentation (PSI) versus conventional instrumentation (CI) in shoulder arthroplasties: A Meta-Analysis and Systematic Review.

Pre-operative planning with X-PSI™ compared to MRI-based patient-specific instrumentation in total knee arthroplasty.

Pre-operative planning with X-PSI™ compared to MRI-based patient-specific instrumentation in total knee arthroplasty.

Patient-specific instrumentation improved clinical outcome and implant survival but is not superior compared to conventional total knee arthroplasty: Ten years follow-up of a multicenter double-blind randomized controlled trial.

Patient-specific instrumentation (PSI) is a commonly used technique designed to improve mechanical alignment in total knee arthroplasty (TKA) and was therefore believed to lead to better clinical outcome and implant survival rates compared with conventional instruments (CIs). To date, long-term results comparing these two techniques are not available. This study is a 10-year follow-up of a previous double-blind multicenter randomized controlled trial where PSI was compared with CI. Patients with osteoarthritis of the knee who were candidates for TKA were included. Exclusion criteria were metal near the knee-, ankle- or hip joint, patients with contra-indications for a magnetic resonance imaging (MRI) scan and patients who had previous knee surgery (except arthroscopic meniscectomy). Clinical outcomes were assessed using patient-reported outcome measures (PROMs), and the analysis was performed with a general linear mixed model for repeated measurements. Kaplan-Meier curves were used to compare revision rates. X-rays were obtained and examined by two individual reviewers for any signs of loosening of the components. At a mean follow-up of 10.1 (SD 0.1) years, 129 patients (loss to follow-up 23%) were analysed in this trial. No statistically significant difference between the two groups were found for any of the PROMs and revision rates were comparable, six in the PSI group and three in the CI group (p = 0.29). Two X-rays in the PSI group showed a radiolucent line of the femoral component. At 10-year follow-up, PSI does not lead to better clinical outcome or survival of the prosthesis compared with CI. Level 1.

Femoral resection accuracy and precision in manual caliper-verified kinematic alignment total knee arthroplasty.

The accuracy and precision of bone resections in total knee arthroplasty (TKA) are essential to avoid poor implant positioning, which can lead to component wear, pain, and instability, reducing patient satisfaction and implant survivorship. Technology-assisted TKA techniques aim to improve accuracy but come with added costs, increased operative time, and varying success in clinical outcomes. Caliper-verified kinematic alignment (KA) attempts to restore the joint line by precisely measuring resections to equal implant thickness. We evaluated the accuracy and precision of caliper-verified KA-TKA performed with manual instruments. We hypothesised that this technique would achieve high accuracy and precision, with an average absolute difference between actual and target distal and posterior femoral resection measurements of ≤ 0.5 mm. 385 consecutive patients underwent primary unrestricted caliper-verified KA-TKA with manual instrumentation. The thickness of the distal medial (DM), distal lateral (DL), posterior medial (PM) and posterior lateral (PL) femoral condyle resections were measured with a caliper and compared to a target determined by the degree of cartilage loss, saw blade kerf, and femoral component thickness. The mean differences between the resected and target thicknesses for DM, DL, PM and PL femoral resections were 0.1 ± 0.2 mm, 0.1 ± 0.3 mm, 0.3 ± 0.5 mm and 0.2 ± 0.4 mm, respectively (mean ± std. dev.). Most femoral resections were within 0.5 mm of the target-97.7%, 94.5%, 85.7% and 89.4% of DM, DL, PM and PL resections, respectively. Manual caliper-verified KA-TKA achieved highly accurate and precise femoral resections with absolute differences from target that averaged 0.175 mm. This simple, logical, efficient, and reproducible surgical technique may be an option for surgeons contemplating the use of technology-assisted options, such as patient-specific instrumentation or robotic arm-assisted TKA, and surgeons without access to such technologies. Level II.

Accuracy of total knee arthroplasty using hospital-based 3D printed Patient-specific instrumentation: A radiology research

Accuracy of total knee arthroplasty using hospital-based 3D printed Patient-specific instrumentation: A radiology research

Three-Dimensional-Planned Patient-Specific Guides for Scaphoid Reconstruction: A Comparative Study of Primary and Revision Nonunion Cases.

Background: Scaphoid reconstruction after an established non- or malunion is challenging and recent developments have shown the feasibility to reconstruct it with 3D-planned and -printed patient-specific instrumentation. Methods: Our study compared the clinical outcome of computer assisted 3D-reconstructions of the scaphoid using patient-specific guides for primary and revision reconstructions of scaphoid nonunion regarding clinical outcome. Therefore, 39 patients with primary scaphoid nonunion or malunion and 15 patients with nonunion or malunion after a previous operative treatment were treated with patient-specific guides and followed up for a mean of 10.5 months. The consolidation was assessed with a CT-scan, and the time to consolidation was recorded. Pain level, satisfaction, wrist range of motion, and grip strength were measured and compared. Results: The wrist range of motion and grip strength of the two groups were similar, except for the wrist extension, which was significantly reduced in the revision group. Consolidation was observed in 36/39 patients (92%) in the primary group and in 13/15 patients (87%) in the revision group. Our results showed similar clinical results postoperatively between primary reconstructions and revision surgery. Conclusions: The use of 3D-planned and -printed patient-specific instrumentation proves to be similarly effective in revision surgeries for the reconstruction of the scaphoid as it is in primary surgeries.

Applications and Effectiveness of 3D Printing in Various Ankle Surgeries: A Narrative Review.

Technological advancements have made three-dimensional printing prevalent in orthopedic surgery. It facilitates the production of customized implants and tailored patient instruments, enhancing surgical planning and results. This review focuses on the uses and effectiveness of patient-specific products manufactured using three-dimensional printing in ankle surgery. A search of databases-PubMed, Embase, Cochrane Library, and Google Scholar-yielded 41 articles for review. Total talus replacement offers a viable alternative to standard treatments like arthrodesis and total ankle arthroplasty. Custom implants and patient-specific instrumentation in total ankle arthroplasty procedures guarantee a tailored fit and accurate alignment. For arthrodesis, three-dimensional printing enables the production of cages, effectively solving issues associated with conventional bone grafts, such as poor bone quality, significant defects, and nonunion. Additionally, patient-specific instrumentation facilitates the swift and accurate placement of Kirschner wires at the correct sites. When performing supramalleolar osteotomy, patient-specific instrumentation leads to shorter operation times, reduced blood loss, and less radiation exposure. Three-dimensional printing is increasingly employed in ankle surgeries, and as technology advances, it is anticipated to become critical for addressing complex ankle issues.

Advancements and applications of 3D printing in pediatric orthopedics: A comprehensive review.

Preoperative planning is crucial for successful surgical outcomes. 3D printing technology has revolutionized surgical planning by enabling the creation and manufacturing of patient-specific models and instruments. This review explores the applications of 3D printing in pediatric orthopedics, focusing on image acquisition, segmentation, 3D model creation, and printing techniques within specific applications, including pediatric limb deformities, pediatric orthopedic oncology, and pediatric spinal deformities. 3D printing simultaneously enhances surgical precision while reducing operative time, reduces complications, and improves patient outcomes in various pediatric orthopedic conditions. 3D printing is a transformative technology in pediatric orthopedics, offering significant advantages in preoperative planning, surgical execution, and postoperative care.

Current concepts and treatment options for complex glenoid bone defects : Patient-specific instrumentation and custom-made implants

Glenoid bone defects are frequent and the etiology is multifactorial. To prevent increased loosening rates of the glenoid component in total shoulder arthroplasty (TSA), various techniques are available to address the loss of glenoid bone. When corrective reaming and bone grafting techniques are no longer sufficient, patient-specific instrumentation (PSI) and custom-made implants have become core strategies for managing these defects. Following precise planning based on computed tomography (CT) imaging and three-dimensional reconstruction of the bony surface, an individualized guide can be used to accurately position the implant. When the limits of bone reconstruction have been reached, specially prepared (custom-made) implants can be used to compensate for the bony defect. Patients often require minimal postoperative immobilization of the shoulder joint. The currently limited literature describes favorable clinical outcomes, although these findings are almost exclusively limited to reverse shoulder arthroplasty.

Rejection rate, modifications, and turnaround time for patient specific instrumentation plans in total ankle replacement.

Rejection rate, modifications, and turnaround time for patient specific instrumentation plans in total ankle replacement.

Do patient-specific cutting guides for pelvic and sacral tumour resection provide tumour-free bone margins?

Do patient-specific cutting guides for pelvic and sacral tumour resection provide tumour-free bone margins?

Distal tibial osteophytes are more accurate than medial malleolar anatomy when using patient specific instrumentation in total ankle replacement.

Distal tibial osteophytes are more accurate than medial malleolar anatomy when using patient specific instrumentation in total ankle replacement.