Patient-specific Instrumentation Research Articles

Surgical strategy and complication management of osteotomy around the painful degenerative varus knee: ESSKA Formal Consensus Part II.

The purpose of the European consensus was to provide recommendations for the treatment of patients with a painful degenerative varus knee using a joint preservation approach. Part II focused on surgery, rehabilitation and complications after tibial or femoral correction osteotomy. Ninety-four orthopaedic surgeons from 24 countries across Europe were involved in the consensus, which focused on osteotomies around the knee. The consensus was performed according to the European Society for Sports Traumatology, Knee Surgery and Arthroscopy consensus methodology. The steering group designed the questions and prepared the statements based on the experience of the experts and the evidence of the literature. The statements were evaluated by the ratings of thepeer-review groups before a final consensus was released. The ideal hinge position for medial opening wedge high tibial osteotomy (MOW HTO) should be at the upper level of the proximal tibiofibular joint, and for lateral closing wedge distal femoral osteotomy (LCW DFO) just above the medial femoral condyle. Hinge protection is not mandatory. Biplanar osteotomy cuts provide more stability and quicker bony union for both MOW HTO and LCW DFO and are especially recommended for the latter. Osteotomy gap filling is not mandatory, unless structural augmentation for stabilityis required. Patient-specific instrumentation should be reserved for complex cases by experienced hands. Early full weight-bearing can be adopted after osteotomy, regardless of the technique. However, extra caution should be exercised in DFO patients. Osteotomy patients should return to sports within 6 months. Clear recommendations for surgical strategy, rehabilitation and complications of knee osteotomies for the painful degenerative varus kneewere demonstrated. In Part 2of the consensus, high levels of agreement were reached by experts throughout Europe, under variable working conditions. Where science islimited, the collated expertise of the collaborators aimed at providing guidance for orthopaedic surgeons developing an interest in the fieldand highlighting areas for potential future research. Level II, consensus.

Improving standard volar plate fixation in 3D-guided corrective osteotomy of the distal radius: evaluation of a shim instrument.

Standard volar plates often do not fit the surface of the malunited distal radius after osteotomy, necessitating an offset angle for accurate volar tilt correction. The correction can be achieved if the plate is held at the correct angle when the distal screws are locked. With the advantage of 3D surgical planning and patient-specific instruments, we developed a shim instrument to assist the surgeon in securing the plate at the intended angle when locking the distal screws, and evaluated radiological results. Five female patients aged 63-74 with dorsally angulated extra-articular malunions underwent surgery using 3D-printed guides and the shim instrument. The plate position, drilling guide alignment, screw placements, and distal radius correction on postoperative CTs were compared with the surgical plans. Errors were measured using an anatomical coordinate system, and standard 2D radiographic measures were extracted. Preoperative dorsal tilt ranged from 16° to 35°, and postoperative volar tilt from 1° to 11°. 3D analysis revealed mean absolute correction errors of 6.1° in volar tilt, 1.6° in radial inclination, and 0.6 mm in ulnar variance. The volar tilt error due to the shim instrument, indicated by the mean angle error of the distal screws to the plate, was 2.1° but varied across the five patients. Settling of the distal radius, due to tension during and after reduction, further contributed to a mean loss of 3.5° in volar tilt. The shim instrument helped with securing plates at the intended angle; however, further correction improvements should consider the tension between the fragments of osteoporotic bone.

Use of Computed Tomography for Shoulder Arthroplasty: A Systematic Review

IntroductionThe prevalence of total shoulder arthroplasties is on the rise annually. Improvements in implant quality, construct stability, and surgical techniques have notably enhanced post-operative results, prompting an expansion of indications for shoulder arthroplasty. Despite its high success rate, opportunities for enhancement remain, especially in preoperative planning and intraoperative execution. Advanced imaging technologies offer significant potential in optimizing implant placement, thus improving the longevity of the procedure. To our knowledge, a comprehensive review examining the impact of advanced imaging on shoulder arthroplasty has yet to be conducted. This systematic review aims to investigate the benefits of advanced imaging technologies in this context, focusing on their application in preoperative planning, osteoarthritis assessment, intraoperative adjustments, patient-specific instrumentation, and navigational aids. MethodsThis review utilized a comprehensive search of PubMed to identify relevant studies published from 2000 to 2024, focusing on the application of various imaging techniques in shoulder arthroplasty. The search was conducted by two authors and centered on plain radiography, CT scans, and MRI. The selection criteria included availability of full-text articles, English language, direct comparison of imaging techniques, and a focus on patient outcomes, including discussions on broader applications such as intraoperative navigation and patient-specific instrumentation development. ResultsEnhanced imaging techniques, particularly CT scans and MRIs, have been shown to significantly improve outcomes in shoulder arthroplasty. While plain radiographs remain standard, CT scans provide superior bony detail, crucial for evaluating glenoid wear and determining augmentation needs. Preoperative CT imaging has been demonstrated to enhance implant placement accuracy. Moreover, intraoperative technologies based on CT imaging, such as patient-specific instrumentation and navigation systems, contribute to better surgical results. ConclusionThe benefits of CT imaging in shoulder arthroplasty significantly outweigh the associated costs. Current literature strongly supports the adoption of CT imaging in these procedures, particularly when used alongside modern operative technologies.

Does patient-specific instrumentation in primary total knee arthroplasty improve long-term satisfaction or function? A randomized trial with a 9-year follow-up

Background: Patient-specific instrumentation (PSI) aims to increase the accuracy of total knee arthroplasty (TKA). However, the long-term benefit compared to conventional instrumentation (CI), is still controversial. This randomized controlled trial compares the long-term outcomes between PSI and CI in TKA. Methods: Patients submitted to PSI or CI TKA with a minimum follow-up of 8 years were evaluated. Satisfaction levels, forgotten joint score (FJS) and Western Ontario and McMaster university osteoarthritis index (WOMAC) scores were compared. Regarding descriptive statistics, mean, standard deviation and frequencies were obtained. For inferential statistics we used the t test for independent samples the Mann-Whitney test and the Wilcoxon Test. Results: A total of 50 TKA were included (48% CI; 52% PSI) with an average follow-up time of 9.3 years. At the final follow-up the WOMAC score was similar between groups (p=0.846; CI:26.8±22.5; PSI:26.8±25.3). Similarly, no differences were seen for the FJS (p=0.785; CI:59.6±35.1; PSI:57.1±36.2) or satisfaction (p=0.486; CI:8.1±2.8; PSI:9.1±1.4). However, at the final follow-up, the total WOMAC score had worse results when compared to the previous evaluations (p=0.013 for CI group; p=0.009 for PSI group). No significant differences in the satisfaction levels were detected regarding the initial and final evaluations (p=0.581 for CI group; p=0.936 for PSI group). Conclusions: Nine years after TKA, PSI and CI patients reported similar levels of satisfaction and functioning. Both groups achieved similar results concerning the WOMAC, FJS scores and satisfaction levels. This study suggests that long-term satisfaction and functioning levels are similar in both PSI and CI.

High-Temperature Polylactic Acid Proves Reliable and Safe for Manufacturing 3D-Printed Patient-Specific Instruments in Pediatric Orthopedics-Results from over 80 Personalized Devices Employed in 47 Surgeries.

(1) Background: Orthopedic surgery has been transformed by 3D-printed personalized instruments (3DP-PSIs), which enhance precision and reduce complications. Hospitals are adopting in-house 3D printing facilities, using cost-effective methods like Fused Deposition Modeling (FDM) with materials like Polylactic acid (PLA) to create 3DP-PSI. PLA's temperature limitations can be overcome by annealing High-Temperature PLA (ann-HTPLA), enabling steam sterilization without compromising properties. Our study examines the in vivo efficacy of ann-HTPLA 3DP-PSI in pediatric orthopedic surgery. (2) Methods: we investigated safety and efficacy using ann-HTPLA 3DP-PSI produced at an "in-office" 3D-printing Point-of-Care (3DP-PoC) aimed at correcting limb deformities in pediatric patients. Data on 3DP-PSI dimensions and printing parameters were collected, along with usability and complications. (3) Results: Eighty-three ann-HTPLA 3DP-PSIs were utilized in 33 patients (47 bone segments). The smallest guide used measured 3.8 cm3, and the largest measured 58.8 cm3. Seventy-nine PSIs (95.2%; 95% C.I.: 88.1-98.7%) demonstrated effective use without issues. Out of 47 procedures, 11 had complications, including 2 infections (4.3%; 95% CI: 0.5-14.5%). Intraoperative use of 3DP-PSIs did not significantly increase infection rates or other complications. (4) Conclusions: ann-HTPLA has proven satisfactory usability and safety as a suitable material for producing 3DP-PSI in an "in-office" 3DP-PoC.

Fluoroscopically calibrated 3D-printed patient-specific instruments improve the accuracy of osteotomy during bone tumor resection adjacent to joints

BackgroundInadequate surface matching, variation in the guide design, and soft tissue on the skeletal surface may make it difficult to accurately place the 3D-printed patient-specific instrument (PSI) exactly to the designated site, leading to decreased accuracy, or even errors. Consequently, we developed a novel 3D-printed PSI with fluoroscopy-guided positioning markers to enhance the accuracy of osteotomies in joint-preserving surgery. The current study was to compare whether the fluoroscopically calibrated PSI (FCPSI) can achieve better accuracy compared with freehand resection and conventional PSI (CPSI) resection.MethodsSimulated joint-preserving surgery was conducted using nine synthetic left knee bone models. Osteotomies adjacent to the knee joint were designed to evaluate the accuracy at the epiphysis side. The experiment was divided into three groups: free-hand, conventional PSI (CPSI), and fluoroscopically Calibrated PSI (FCPSI). Post-resection CT scans were quantitatively analyzed. Analysis of variance (ANOVA) was used.ResultFCPSI improved the resection accuracy significantly. The mean location accuracy is 2.66 mm for FCPSI compared to 6.36 mm (P < 0.001) for freehand resection and 4.58 mm (P = 0.012) for CPSI. The mean average distance is 1.27 mm compared to 2.99 mm (p < 0.001) and 2.11 mm (p = 0.049). The mean absolute angle is 2.16° compared to 8.50° (p < 0.001) and 5.54° (p = 0.021). The mean depth angle is 1.41° compared to 8.10° (p < 0.001) and 5.32° (p = 0.012). However, there were no significant differences in the front angle compared to the freehand resection group (P = 0.055) and CPSI (P = 0.599) group. The location accuracy observed with FCPSI was maintained at 4 mm, while CPSI and freehand resection exhibited a maximum deviation of 8 mm.ConclusionThe fluoroscopically calibrated 3D-printed patient-specific instruments improve the accuracy of osteotomy during bone tumor resection adjacent to joint joints compared to conventional PSI and freehand resection. In conclusion, this novel 3D-printed PSI offers significant accuracy improvement in joint preserving surgery with a minimal increase in time and design costs.

Is AI 3D-printed PSI an accurate option for patients with developmental dysplasia of the hip undergoing THA?

BackgroundIn traditional surgical procedures, significant discrepancies are often observed between the pre-planned templated implant sizes and the actual sizes used, particularly in patients with congenital hip dysplasia. These discrepancies arise not only in preoperative planning but also in the precision of implant placement, especially concerning the acetabular component. Our study aims to enhance the accuracy of implant placement during Total Hip Arthroplasty (THA) by integrating AI-enhanced preoperative planning with Patient-Specific Instrumentation (PSI). We also seek to assess the accuracy and clinical outcomes of the AI-PSI (AIPSI) group in comparison to a manual control group.MethodsThis study included 60 patients diagnosed with congenital hip dysplasia, randomly assigned to either the AIPSI or manual group, with 30 patients in each. No significant demographic differences between were noted the two groups. A direct anterior surgical approach was employed. Postoperative assessments included X-rays and CT scans to measure parameters such as the acetabular cup anteversion angle, acetabular cup inclination angle, femoral stem anteversion angle, femoral offset, and leg length discrepancy. Functional scores were recorded at 3 days, 1 week, 4 weeks, and 12 weeks post-surgery. Data analysis was conducted using SPSS version 22.0, with the significance level was set at α = 0.05.Results and conclusionThe AIPSI group demonstrated greater prosthesis placement accuracy. With the aid of PSI, AI-planned THA surgery provides surgeons with enhanced precision in prosthesis positioning. This approach potentially offers greater insights and guidelines for managing more complex anatomical variations or cases.

Factors Causing Unintended Sagittal and Axial Alignment Changes in High Tibial Osteotomy: Comparative 3-Dimensional Analysis of Simulation and Actual Surgery

Background: Unintended secondary changes in the posterior tibial slope (PTS) and tibial torsion angle (TTA) may occur after medial open-wedge high tibial osteotomy (MOWHTO). In surgical procedures using patient-specific instruments (PSIs), it is essential to reproduce the PTS and TTA that were planned in simulations. Purpose: To analyze the factors causing unintended sagittal and axial alignment changes after MOWHTO. Study Design: Case series; Level of evidence, 4. Methods: Overall, 63 patients (70 knees) who underwent MOWHTO using a PSI between June 2020 and June 2023 were retrospectively reviewed. Preoperative and postoperative computed tomography scans were 3-dimensionally reconstructed. Simulated osteotomy was performed so that the weightbearing line could pass through the target point. A PSI gapper was 3-dimensionally printed to fit the posteromedial corner of the osteotomy gap in the simulated HTO model. After MOWHTO using the PSI gapper, the actual postoperative model was compared with the preoperative or simulation model. This assessment included PTS, TTA, hinge axis, and osteotomy-related parameters. Cortical breakage around the lateral hinge was evaluated to assess stability. Results: The mean PTS and TTA did not change in the simulation. However, significant changes were observed in the actual postoperative PTS and TTA (change, –2.4°± 2.2° and −3.9°± 4.7°, respectively). The PTS was reduced, while the TTA decreased with internal rotation of the distal fragment. The difference in the axial hinge axis angle (AHA) between the simulation and actual surgery was the factor most correlated with the difference in the PTS (r = 0.625; P < .001). In regression analysis, the difference in the AHA was the only factor associated with the difference in the PTS (β = 0.558; P = .001), and there were no factors that showed any significant associations with the difference in the TTA. In subgroup analyses for the change in the TTA, the correction angle and anterior osteotomy angle were significantly higher in the more internal rotation group (P = .023 and P = .010, respectively). The TTA change was significantly higher in the unstable group with lateral cortical breakage (P = .018). The unstable group was more likely to show an internal rotation of ≥5° (odds ratio, 5.0; P = .007). Conclusion: The AHA was associated with a difference in the PTS between the simulation and actual surgery. The change in the TTA was caused by a combination of multiple factors, such as a large correction angle and anterior osteotomy angle, but mainly by instability of the lateral cortical hinge.

Single-Center, Early Experience with the First 3D-Printed Surface, Fixed Bearing, Total Ankle Arthroplasty: A Minimum of 2-Year Follow-Up

Introduction/Purpose: As the fourth generation of total ankle arthroplasty (TAA) implants evolve, treatment solutions for end- stage ankle arthritis continue to improve. Technological advancements in CT guided planning and 3-D printing offers surgeons the ability to perform TAA with patient specific instrumentation and implants. 3-D printed components are designed to act as scaffold in hopes to facilitate early in-growth, to increase implant stability, to support long-term survivorship, and ultimately to improve the quality of life our patients. We present our early experience at a single academic center with a minimum of 2-year follow up data on the first 3-D printed, fixed bearing, TAA in the United States. We hypothesize that 3-D printed technology will demonstrate improved long-term survival and increased bony in-growth on the implant-bone interface. Methods: A retrospective review was performed on patients who underwent TAA with a minimum of 2-year clinical and radiographic data in which this 3-D printed TAA was utilized at our single academic center. Patient demographic, radiographic, and functional outcome scores were collected preoperatively, at 6 months, 1 year, and 2 years. The severity of ankle arthritis and associated deformities in patients were stratified using the COFAS classification. The primary outcomes of this study were implant survivorship, comparative analysis of preoperative and postoperative Patient Reported Outcomes Measurement Information System (PROMIS) physical function scores, VAS pain scores, radiographic development of linear radiolucency &gt;2 mm, cystic radiolucency &gt; 5mm, subsidence, and adverse events within 2 years of surgery. Results: Thirty patients were included with a median follow-up of 26 months (range, 24-36 months). Implant survival rate was 90%. One patient was revised to a stemmed TAA secondary to tibial subsidence. One patient required a TTC fusion secondary to Charcot collapse. One patient was revised to a staged ankle fusion secondary to periprosthetic joint infection. Two patients (6.7%) experienced linear radiolucency &gt;2mm with tibial subsidence in which one patient required a revision TAA (mentioned above) and another who was asymptomatic. No significant cystic radiolucency &gt;5 mm were identified. Five patients required re-operation from complications unrelated to the implant. VAS scores decreased significantly from 6 (IQR, 4-8) to 1 (IQR, 2-4) (P &lt;.001; r=0.55). PROMIS Physical scores increased significantly from 43.6 (IQR, 33-47.7) to 50.8 (44.8-57.7)(P &lt;.001; r=0.60). Conclusion: The utilization of this new 3-D printed, fixed bearing TAA demonstrated a ninety percent overall implant survival rate in our small cohort of patients. Further data will be required to determine the long term efficacy of this new 3-D printed implant on patient outcomes. Our early experience and complications presented in our study demonstrate that this 3-D printed TAA implant is safe and effective in the treatment of end-stage ankle arthritis.

Computer-based pre- and intra-operative planning modalities for Total Knee Arthroplasty: A comprehensive review

Introduction Since the introduction of total knee arthroplasty (TKA) into modern medicine, many types of digital pre- and intra-operative planning methods have been introduced. Due to the abundance of planning modalities for TKA, physicians are posed with the challenge of which type to implement into their daily practice. In the current fast-paced and research-driven medical environment it is important to understand the differences between the computer-based pre- and intra-operative planning modalities for TKA. Materials and methods The following databases were searched: MedLine, EMBASE, Web of Science, and the Cochrane Library. All articles were independently reviewed by the two reviewers (DS, ID). The following data were extracted, if available: study ID, country of conduction, type of planning modality or modalities, and the use and explanation of historical and currently employed pre- and intra-operative planning modalities for TKA. Results 39 studies were included into the systematic review. Computer assisted surgery (CAS) represents a surgical concept where computer technology is used for surgical planning. CAS for TKA was introduced in the late 1980s. Subsequently, three different types of CAS were developed to plan TKA. The first type of CAS, computer integrated instruments, also known as CAS navigation, provides a real-time view of anatomy and marked surgical instruments intra-operatively. For the second type of CAS, rapid prototyping, or 3D printing, was derived from CAS technology in which the development of patient specific instrumentation (PSI) for TKA followed. Furthermore, CAS aided the evolution of the third type of CAS for TKA: robotics. Conclusion With a high demand for TKA surgery, the challenge to achieve more accurate alignment, improved prosthesis survival, and improved patient satisfaction rates is a very topical one. Planning modalities for TKA were developed to address this demand. This comprehensive systematic review showed that the monumental development of digital planning modalities for TKA has led to a vast amount of well-researched options that surgeons can choose from and use in daily practice.

Feel, move, or walk? Which has a greater contribution to functioning in total knee arthroplasty? A comparative study between two instrumentations based on a classification and regression tree

Background: This study aimed to know which variables most contribute to the functioning acquired in the third month using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and a multivariate analysis through classification and regression tree (CRT), comparing the conventional instrumentation (CI), and patient-specific instrumentation (PSI). Methods: This is an observational and retrospective study. The sample consisted of 252 patients, 68 receiving CI (27.0%) and 184 receiving PSI (73.0%). The functional variables of the study were: knee pain, passive flexion and extension, gait distance and the domains of the WOMAC index. Results: The CRT method identified that the only explanatory variable that contributed to the highest functioning in the CI group (13.2 in the WOMAC) was pain in the third month with a value ≤2.5 in the visual analog scale (VAS). In the PSI group, the variable that best explained functioning was pain in the first postoperative month (VAS ≤4.5), with the best functional result (2.8 in WOMAC) referring to the patients who walked &gt;320.5 m in the 6-minute walk test in the first month and who had flexion of &gt;112.5 in the third month. Conclusions: Feeling pain is the variable with the most significant explanatory power for the results achieved in functioning at the third month, regardless of the arthroplasty instrumentation employed. Moving the knee in higher flexion ranges and obtaining higher mean values of gait speed also positively influences functioning in patients subjected to PSI.

First long-term analysis of survival and clinical outcome in patient-specific instrumentation for total knee arthroplasty: follow-up of a prospective cohort study.

Patient-specific instrumentation (PSI) was introduced to improve post-operative alignment, and consequently the revision rate and clinical results after total knee arthroplasty (TKA). Short- to mid-term data are conflicting regarding these theoretical advantages of PSI. The purpose of this retrospective analysis was to evaluate the survival rate and clinical outcome in PSI TKA 8.4 years after initial surgery. To our knowledge, no other study investigated long-term follow-up of TKA procedures using PSI. From a total cohort of 184 consecutive patients (200 TKA) 136 patients (144 TKA, 72%) were prospectively analysed at a mean follow-up of 8.4 years (±0.4). A survival analysis with all-cause revision of TKA as endpoint was performed. Patient-reported outcome measures (PROMs) were obtained preoperatively and after 1-, 2-, 5-, and 8.4-years of follow-up. Differences between these moments of follow-up were analysed. At final follow-up, 4 TKAs (2%) had undergone revision, all between 2-4 years after primary surgery. Reasons for revision were late infection, aseptic loosening, instability and polyethylene insert breakage. The median score of certain PROMs (WOMAC, VAS, EQ-index, EQ-VAS) decreased compared to previous follow-up scores but were significantly higher than preoperative scores. After 8.4 years of follow-up, no additional revision surgery was performed compared to 5-years postoperatively. Certain PROMs at 8.4-year follow-up decreased compared to earlier moments of follow-up, but all PROMs improved compared to preoperative PROMs.

Financial Conflicts of Interest and Industry Funding are Associated With Conclusions Favorable to New Technologies: A Review of Published Economic Analyses in Hip and Knee Arthroplasty

BackgroundNew technologies in hip and knee arthroplasty are commonly evaluated using cost-effectiveness analyses and similar economic assessments. There is a wide variation in the methodology of these studies, introducing the potential for bias. The purpose of this study was to evaluate associations between potential financial conflicts of interest (COI) and the outcomes of economic analyses. We hypothesized that authors’ COI and industry funding would be associated with conclusions favorable to a new technology. MethodsEconomic analyses making cost-effectiveness or economic implementation claims on patient-specific instrumentation, robotics, and implants used in hip and knee arthroplasty published from 2010 to 2022 were identified. Papers were evaluated to determine if conclusions were favorable to the new technology being studied. Fisher’s exact test was utilized to determine the relationship between the presence of COI and an article’s conclusions. ResultsOf 43 eligible articles, 76.7% were cost-effectiveness analyses, 23.2% were cost analyses, and 67.4% of articles had conclusions favorable to a technology. Of the 29 articles with favorable conclusions, 26 had an author with a financial COI (89.7%), and 14 had industry funding (48.3%). Of the 33 articles with a financial COI, 26 (78.8%) had favorable conclusions, and of the 16 articles with industry funding, 14 (87.5%) had favorable conclusions. Fisher’s exact test revealed a statistically significant association between an article having favorable conclusions and the presence of an author’s COI or industry funding (odds ratio, 13.5; 95% CI [confidence interval], 2.3 to 79.9; P = .003). ConclusionsFinancial COIs were present in 79.1% of lower extremity arthroplasty economic analyses on technologies and were associated with an article having conclusions favorable to the new technology. Surgeons and decision-makers should be aware of the variability and assumptions in these studies and the potential bias of the conclusions.

Foot &amp; Ankle

The February 2024 Foot &amp; Ankle Roundup360 looks at: Survival of revision ankle arthroplasty; Tibiotalocalcaneal nail for the management of open ankle fractures in the elderly patient; Accuracy of a patient-specific total ankle arthroplasty instrumentation; Fusion after failed primary ankle arthroplasty: can it work?; Treatment options for osteochondral lesions of the talus; Managing hair tourniquet syndrome of toe: a rare emergency; Ultrasound-guided collagenase therapy for recurrent plantar fibromatosis: a promising line of therapy?.

Oncology

The February 2024 Oncology Roundup360 looks at: Does primary tumour resection improve survival for patients with sarcomas of the pelvis with metastasis at diagnosis?; Proximal femur replacements for an oncologic indication offer a durable endoprosthetic reconstruction option: a 40-year experience; The importance of awaiting biopsy results in solitary pathological proximal femoral fractures: do we need to biopsy solitary pathological fractures?; Effect of radiotherapy on local recurrence, distant metastasis, and overall survival in 1,200 extremity soft-tissue sarcoma patients; What to choose in bone tumour resections? Patient-specific instrumentation versus surgical navigation; Optimal timing of re-excision in synovial sarcoma patients: immediate intervention versus waiting for local recurrence; Survival differences of patients with resected extraskeletal osteosarcoma receiving two different (neo) adjuvant chemotherapy regimens; Solitary versus multiple bone metastases in the appendicular skeleton: should the surgical treatment be different?.

Internal hemipelvectomy: A single institution's learning curve and longitudinal experience.

Wide margin resection for pelvic tumors via internal hemipelvectomy is among the most technically challenging procedures in orthopedic oncology. As such, surgeon experience and technique invariably affect patient outcomes. The aim of this clinical study was to assess how an individual surgeon's experiences and advancements in technology and techniques in the treatment of internal hemipelvectomy have impacted patient outcomes at our institution. This study retrospectively examined a single tertiary academic institution's consecutive longitudinal experience with internal hemipelvectomy for primary sarcoma or pelvic metastases over a 26-year period between the years 1994 and 2020. Outcomes were assessed using two separate techniques. The first stratified patients into cohorts based on the date of surgery with three distinct "eras" ("early," "middle," and "modern"), which reflect the implementation of new techniques, including three-dimensional (3D) computer navigation and cutting guide technology into our clinical practice. The second method of cohort selection grouped patients based on each surgeon's case experience with internal hemipelvectomy ("inexperienced," "developing," and "experienced"). Primary endpoints included margin status, complication profiles, and long-term oncologic outcomes. Whole group multivariate analysis was used to evaluate variables predicting blood loss, operative time, tumor-free survival, and mortality. A total of 72 patients who underwent internal hemipelvectomy were identified. Of these patients, 24 had surgery between 1994 and 2007 (early), 28 between 2007 and 2015 (middle), and 20 between 2016 and 2020 (modern). Twenty-eight patients had surgery while the surgeon was still inexperienced, 24 while developing, and 20 when experienced. Evaluation by era demonstrated that a greater proportion of patients were indicated for surgery for oligometastatic disease in the modern era (0% vs. 14.3% vs. 35%, p = 0.022). Fewer modern cases utilized freehand resection (100% vs. 75% vs. 55%, p = 0.012), while instead opting for more frequent utilization of computer navigation (0% vs. 25% vs. 20%, p = 0.012), and customized 3D-printed cutting guides (0% vs. 0% vs. 25%, p = 0.002). Similarly, there was a decline in the rate of massive blood loss observed (72.2% vs. 30.8% vs. 35%, p = 0.016), and interdisciplinary collaboration with a general surgeon for pelvic dissection became more common (4.2% vs. 32.1% vs. 85%, p < 0.001). Local recurrence was less prevalent in patients treated in middle and modern eras (50% vs. 15.4% vs. 25%, p = 0.045). When stratifying by case experience, surgeries performed by experienced surgeons were less frequently complicated by massive blood loss (66.7% vs. 40% vs. 20%, p = 0.007) and more often involved a general surgeon for pelvic dissection (17.9% vs. 37.5% vs. 65%, p = 0.004). Whole group multivariate analysis demonstrated that the use of patient-specific instrumentation (PSI) predicted lower intraoperative blood loss (p = 0.040). However, surgeon experience had no significant effect on operative time (p = 0.125), tumor-free survival (p = 0.501), or overall patient survival (p = 0.735). While our institution continues to utilize neoadjuvant and adjuvant therapies following current guideline-based care, we have noticed changing trends from early to modern periods. With the advent of new technologies, we have seen a decline in freehand resections for hemipelvectomy procedures, and a transition to utilizing more 3D navigation and customized 3D cutting guides. Furthermore, we have employed the use of an interdisciplinary team approach more regularly for these complicated cases. Although our results do not demonstrate a significant change in perioperative outcomes over the years, our institution's willingness to treat more complex cases likely obscures the benefits of surgeon experience and recent technological advances for patient outcomes.

The efficacy and safety of patient-specific instrumentation versus conventional instrumentation for unicompartmental knee arthroplasty: Evidence from a meta-analysis.

The aim of this study was to compare the efficacy and safety of patient-specific instrumentation (PSI) and conventional instrumentation (CI) for unicompartmental knee arthroplasty. Our hypothesis was that the PSI would be superior to CI in improving implant positioning and clinical function. We searched electronic databases (PubMed, Web of Science, Embase, and Cochrane) to identify relevant studies published before July 1, 2023 that met our inclusion criteria. The identified reports at least included one of the following outcome variables: coronal component alignment, sagittal component alignment, number of outliers, hip-knee-ankle angle, postoperative complications, operative time and knee joint functional evaluation. For dichotomous variables, we calculated the risk ratio and its 95% confidence interval (CI). For continuous variables, we calculated the mean difference (MD) and its 95% CI. Heterogeneity of the included studies was assessed using the standard chi-square test. Meta-analyses were performed using RevMan 5.4. software. The meta-analysis was registered with PROSPERO (No. CRD42023454160). A total of 9 articles were included in the analysis, consisting of 4 randomized controlled trials and 5 cohort studies. The study population comprised 494 patients, with 262 in the PSI group and 232 in the CI group. Our findings demonstrate that the PSI group exhibits superior tibial component coronal alignment compared to the CI group (MD = -0.66, 95% CI: -1.21 to -0.12, P = .02). Conversely, the CI group demonstrates better femoral component coronal alignment than the PSI group (MD = 0.89, 95% CI: 0.17-1.60, P = .01). No significant between 2 groups differences were observed in tibial component sagittal alignment, femoral component sagittal alignment, tibial coronal axis outliers, tibial sagittal axis outliers, femoral coronal axis outliers, femoral sagittal axis outliers, postoperative complications, operative time, hip-knee-ankle angle, and postoperative knee joint function score. Our study findings suggest that the PSI confer an advantage in achieving superior tibial component coronal alignment, whereas the CI associated with better femoral component coronal alignment. However, no significant differences were observed between the groups in terms of other parameters. Future studies with larger sample sizes are needed to validate these findings.

Flexion contracture can cause component mismatch in the Prophecy® preoperative patient-specific instrumentation for Evolution® medial-pivot knee system.

Patient-specific instrumentation (PSI) systems are used to conduct total knee arthroplasty. PSI reduces operative time, is less invasive and easier to use, and minimizes the risk of errors by providing precise measurements and reducing operating room turnover time. However, a study on the accuracy of Prophecy Evolution PSI (Microport Inc., Arlington, TN, USA) reported that 94% were below the error margin of 1.5mm and 90% had error margins of 1mm. This study aimed to evaluate the accuracy of the Prophecy Evolution PSI system in terms of the thickness of "total" bony resection required to achieve adequate extension/flexion gaps and the component match ratio between preoperative planning and actual component size inserted. Comparisons were made between the sizes of femoral and tibial components planned with PSI and those inserted. The primary outcome was the average preoperative range of motion with and without matched femoral/tibial components. The study further analyzed the proportions of cases in which both the femoral and tibial components matched, neither matched, and only one of the femoral or tibial components matched. The ratio of the same sizes between the PSI planning and those inserted was 50.8% (33 patients) for both the femoral and tibial components. For the femoral component alone, the ratio was 84.6% (55 patients), and for the tibial component, it was 58.4% (38 patients). A receiver-operating characteristic curve analysis indicated that flexion contracture greater than 20° was a significant prognostic factor for the PSI component match group versus the mismatch group. Flexion contracture may cause PSI mismatch. Notably, flexion contracture greater than 20° was a significant risk factor for the PSI component match group versus the mismatch group. During preoperative planning for a patient with flexion contracture, surgeons should prepare for the possibility of inserting an undersized tibial component.

The coronal alignment differs between two-dimensional weight-bearing and three-dimensional nonweight bearing planning in total knee arthroplasty.

The goal of this study is (1) to assess differences between two-dimensional (2D) weight-bearing (WB) and three-dimensional (3D) nonweight-bearing (NWB) planning in total knee arthroplasty (TKA) and (2) to identify factors that influence intermodal differences. Retrospective single-centre analysis of patients planned for a TKA with patient-specific instruments (PSI). Preoperative WB long-leg radiographs and NWB computed tomography were analysed and following radiographic parameters included: hip-knee-ankle angle (HKA) (+varus/-valgus), joint line convergence angle (JLCA), femorotibial subluxation and bony defect classified according to Anderson. Preoperative range of motion was also considered as possible covariate. Demographic factors included age, sex, and body mass index. A total of 352 knees of 323 patients (66% females) with a mean age of 66 ± 9.7 years were analysed. The HKA differed significantly between 2D and 3D planning modalities; varus knees (n = 231): 9.9° ± 5.1° vs. 6.7° ± 4°, p < 0.001; valgus knees (n = 121): -8.2° ± 6° vs. -5.5° ± 4.4°, p < 0.001. In varus knees, HKA (β = 0.38; p < 0.0001) and JLCA (β = 0.14; p = 0.03) were associated with increasing difference between 2D/3D HKA. For valgus knees, HKA (β = -0.6; p < 0.0001), JLCA (β = -0.3; p = 0.0001) and lateral distal femoral angle (β = -0.28; p = 0.03) showed a significant influence on the mean absolute difference. The coronal alignment in preoperative 3D model for PSI-TKA significantly differed from 2D WB state and the difference between modalities correlated with the extent of varus/valgus deformity. In the vast majority of cases, the 3D NWB approach significantly underestimated the preoperative deformity, which needs to be considered to achieve the planned correction when using PSI in TKA. Level III.

Artificial intelligence- and computer-assisted navigation for shoulder surgery.

Background: Over the last few decades, shoulder surgery has undergone rapid advancements, with ongoing exploration and the development of innovative technological approaches. In the coming years, technologies such as robot-assisted surgeries, virtual reality, artificial intelligence, patient-specific instrumentation, and different innovative perioperative and preoperative planning tools will continue to fuel a revolution in the medical field, thereby pushing it toward new frontiers and unprecedented advancements. In relation to this, shoulder surgery will experience significant breakthroughs. Main body: Recent advancements and technological innovations in the field were comprehensively analyzed. We aimed to provide a detailed overview of the current landscape, emphasizing the roles of technologies. Computer-assisted surgery utilizing robotic- or image-guided technologies is widely adopted in various orthopedic specialties. The most advanced components of computer-assisted surgery are navigation and robotic systems, with functions and applications that are continuously expanding. Surgical navigation requires a visual system that presents real-time positional data on surgical instruments or implants in relation to the target bone, displayed on a computer monitor. There are three primary categories of surgical planning that utilize navigation systems. The initial category involves volumetric images, such as ultrasound echogram, computed tomography, and magnetic resonance images. The second type is based on intraoperative fluoroscopic images, and the third type incorporates kinetic information about joints or morphometric data about the target bones acquired intraoperatively. Conclusion: The rapid integration of artificial intelligence and deep learning into the medical domain has a significant and transformative influence. Numerous studies utilizing deep learning-based diagnostics in orthopedics have remarkable achievements and performance.