Total Knee Arthroplasty Implants Research Articles

Translated article] Use of semi-constrained total knee arthroplasty in gonarthrosis with collateral ligament insufficiency: Clinical and functional outcomes

Achieving stability in total knee arthroplasty (TKA) is crucial for long-term implant survival. In cases of severe deformity or ligament laxity, constrained implants may be required. Traditionally, increasing constraint involved intramedullary stems. However, there are intermediary alternatives, including employing a constrained polyethylene insert without stems, thereby avoiding complications related to them. The study aims to evaluate our experience with a non-modular constrained (NMC) implant in primary TKA. We conducted a retrospective review of the clinical and radiographic outcomes of 108 non-stemmed primary TKAs performed at our institution between 2013 and 2021 in patients with at least 10° deformity or 10 mm ligament laxity. Data included demographics, preoperative and postoperative deformities, clinical outcomes and revision rates. A total of 103 patients (108 knees) with a mean age of 74 were followed up for a minimum of 2 years. The mean postoperative range of motion was 105°/0°. The median Oxford Knee Score, Knee Society Score and Knee Society Function Score were 43.5, 92 and 90, respectively. 17 knees had varus deformity (mean tibiofemoral angle of 2.7°), and 87 knees had excessive valgus deformity (mean tibiofemoral angle of 15.1°). The remaining 4 knees had a neutral alignment. The mean postoperative tibiofemoral angle was 6.8°. The overall revision rate was 6.5% (7 patients): 3 deep periprosthetic infections, 2 patellar dislocations, 1 stiffness and 1 aseptic loosening. Our experience demonstrates favorable mid-term outcomes with the NMC implant, providing a safe alternative to stemmed implants in primary TKA, particularly in cases of severe deformity or ligament laxity.

Safety notices and registry outlier data measure different aspects of safety and performance of total knee implants: a comparative study of safety notices and register outliers.

Safety notices for medical devices such as total knee arthroplasty (TKA) implants may indicate problems in their design or performance that require corrective action to prevent patient harm. Safety notices are often published on national Ministries of Health or regulatory agencies websites. It is unknown whether problems triggering safety notices identify the same implants as those identified by registries as "outlier." We aimed to assess the extent to which safety notices and outlier identification in registries signal the same or different TKA implants. The CORE-MD tool, an automated web scraper tool, was used to collect safety notices related to TKA implants on 13 national Ministries of Health websites and regulatory agencies. Safety notices were defined according to the Medical Device Regulation (MDR) as "a communication sent by a manufacturer to users or customers in relation to a field safety corrective action." Identified TKA outliers, defined as having a significantly higher revision risk than other comparable TKA implants, were extracted from registry reports. 787 safety notices for 38 TKA implants and 35 TKA outliers were identified, together identifying 47 unique TKA implants. 26 (55%) TKA implants had safety notices and were also outliers, 12 (26%) TKA implants had only safety notices, and 9 (19%) were outliers only. TKA implants with safety notices only had similar types of problems to TKA outliers with safety notices, with "Manufacturing/Packaging/Shipping" problems being most frequent (44%). Cumulative revision risks (1/5/10 years) were lower for TKA implants with safety notices only than for TKA outliers with safety notices. 55% of the TKA with a safety notice were identified as outliers in the registry, whereas around 25% of TKA outliers are not the subject of publicly released safety notices, with safety notices pointing to TKA implants not identified by registries as potentially having a higher risk of failure. This suggests that safety notices and registry outlier data measure different aspects of safety and performance.

Will Mobile-Bearing Total Knee Arthroplasty Be Lost to History? A Comparative Study of Long-Term Follow-Up.

Mobile-bearing (MB) total knee arthroplasty (TKA) implants were introduced as an alternative to fixed-bearing (FB) implants because of their theoretical advantages related to femorotibial rotational mismatch. The purpose of this study is to compare the clinical and radiologic outcomes of MB and FB TKA after approximately 13 years of follow-up. We compared the results of 88 patients with a mean age of 66 years who had received a rotating platform MB implant or a FB implant. The mean follow-up was 13.6 years. The patients were assessed clinically (VAS, ROM, KSS, WOMAC scores) and radiographically before and 13 years after operation. There were no statistically significant differences between the FB and MB groups in terms of clinical outcomes and radiological outcomes (p > 0.05 for all). Although the incidence of complications was higher in the MB group, the findings were not statistically significant compared to the FB group (p > 0.05 for all). Although there were no significant differences in the clinical and radiologic outcomes between the FB and MB groups, the possible higher risk of osteolysis or aseptic loosening in the MB group could be an important clinical implication when selecting the TKA implant.

Long-Term Comparison Safety and Outcomes of Simultaneous, Staggered, and Staged Bilateral Total Knee Arthroplasty

BackgroundThe purpose of this study was to determine the safety and the clinical outcome of simultaneous, bilateral, and staged bilateral total knee arthroplasty (TKA) performed by a single surgeon at one academic institute. MethodsWe prospectively followed and retrospectively compared the results of 7,155 patients (14,310 knees) who had simultaneous bilateral TKA, 6,671 patients (13,342 knees) who had staggered bilateral TKA, and 4,501 patients (9,002 knees) who had staged bilateral TKA. The mean age of the patients was 67, 65, and 69 years, respectively. The mean follow-up was 15.5, 15.3, and 16.1 years, respectively. The prevalence of mortality and complications were assessed in each group. In addition, patients were assessed clinically and radiographically at each follow-up. ResultsThe mortality rate (14 patients, 0.2%) of the patients who underwent simultaneous bilateral TKA was similar to those who underwent staggered bilateral TKA (19 patients, 0.3%) and those who underwent staged bilateral TKA (18 patients, 0.4%) (P > 0.05). The major complication (except death) rate (0.8, 0.5, and 0.4%, respectively) and the minor complication rate (20.7, 19, and 19.6%, respectively) were not significantly different among the three groups (P > 0.05). There was no significant difference in the clinical outcomes, radiographic results, revision rate, or survivorship of TKA implants among the three groups (P > 0.05). Transfusion requirements were different among the three groups (10% in the simultaneous bilateral TKA group, 12% in the staggered bilateral TKA group, and 2% in the staged bilateral TKA group). ConclusionsWe found no significant differences among the simultaneous, staggered, and staged bilateral TKA groups, with regard to the mortality, major complication, minor complication, and revision rates; the survival of TKA implants; and clinical and radiographic results after a mean follow-up of 15.5, 15.3, and 16.1 years, respectively.

Survivorship and Functional Outcomes After Complex Primary Total Knee Arthroplasty With Contemporary Rotating-Hinge Implants

Background: Initial fixed-bearing hinge designs for primary total knee arthroplasty (TKA) had high rates of aseptic loosening. There are limited data on contemporary rotating-hinge implants. Purpose: We sought to determine survivorship and functional outcomes of contemporary rotating-hinge implants used in primary TKA. Methods: Retrospective review identified 54 primary rotating-hinge TKAs implanted in 49 patients from 2014 to 2018 at a single institution. Patients identified were 76% women, the mean body mass index was 29 kg/m2, the mean age was 65 years, and the mean follow-up was 3 years. The primary diagnosis for TKA in all cases was severe instability and ligamentous compromise. Secondary diagnoses included post-traumatic osteoarthritis (11, 20%), neurologic disease (10, 19%), inflammatory arthritis (10, 19%), connective tissue disease (3, 6%), valgus deformity (16, 30%), varus deformity (2, 4%), and recurvatum (2, 4%). Preoperative, postoperative (within 6 weeks), and most recent radiographs were reviewed. In this study, we collected preoperative, 1-year, and 2-year patient-reported outcome measures (PROMs) for patients with primary rotating-hinge TKA. Patient-reported outcome measures were prospectively collected, including the Knee Injury and Osteoarthritis Outcome Survey for Joint Replacement (KOOS JR) scores and the Mental (MCS) and Physical Component Scores (PCS) of the Veterans RAND 12-Item Health Survey (VR-12). Kaplan-Meier analysis was used to determine implant survivorship. Results: Reoperation was required in 6% (3/54); indications included periprosthetic joint infection (1), peripatellar fibrosis (1), and periprosthetic femur fracture (1). At both 2 and 5 years, survivorship free from all-cause reoperation was 95% and from revision for aseptic loosening was 100%. Mean KOOS JR scores increased from 47 preoperatively to 65 at 2 years postoperatively. On radiographic review, there were no progressive radiolucent lines consistent with aseptic loosening at final follow-up. Conclusion: The findings of this single-center, multi-surgeon retrospective case series on the use of rotating-hinge implants for primary TKA suggest excellent 2-year survivorship free from reoperation and no revisions for aseptic loosening. We report modest improvement in a variety of PROMs at 1-year and 2-year follow-up. Despite improvement, clinical outcomes were poor for a primary implant. Longer-term follow-up is required to monitor the durability of primary hinges.

Low UKA implantation volume, comorbidities, male sex, and implantation of constrained TKA are risk factors for septic revision after knee arthroplasty implantation : A register-based study from the German Arthroplasty Register

Periprosthetic joint infection (PJI) is one of the main causes of revision surgeries after total knee arthroplasty (TKA) and unicondylar knee replacement. Patient- and hospital-related risk factors must be evaluated to prevent PJI. This study identifies influencing factors and differences in infection rates between various types of implant. The basis for the data is the German Arthroplasty Register (EPRD). Septic revisions were calculated with the aid of Kaplan-Meier estimates, with septic revision surgery defined as the primary endpoint. Patients with constrained and unconstrained TKA or UKA were analysed using the Holm multiple log-rank test and the Cox proportional hazard model. The 300,998 cases of knee arthroplasty analysed included 254,144 (84.4%) unconstrained TKA, 9993 (3.3%) constrained TKA and 36,861 (12.3%) UKA, with a maximum follow-up of 7 years. After 1 year, the PJI rate was 0.5% for UKA and 2.8% for TKA, whereas after 7 years it was 4.5% for UKA and 0.9% for TKA (p < 0.0001). In constrained TKA, the PJI rate was significantly increased compared with unconstrained TKA (p < 0.0001). After 1 year, the PJI rate was 2.0% for constrained TKA and 0.8% for unconstrained TKA, as well as 3.1% and 1.4% respectively after 7 years. Implantation of a constrained TKA (HR = 2.55), male sex (HR = 1.84), an increased Elixhauser Comorbidity Index score (HR = 1.18-1.56) and an implantation volume of less than 25 UKA per year (HR = 2.15) were identified as risk factors for revision surgeries; an Elixhauser Comorbidity Index score of0 (HR = 0.80) was identified as a preventive factor. A reduced implantation volume and constrained knee arthroplasty are linked to a higher risk of PJI. Comorbidities (increased Elixhauser Comorbidity Index score), male sex and a low UKA-implantation volume were identified as risk factors for PJI. Patients who fulfil these criteria need specific infection prevention measures. Further analyses are required to investigate the potential influence of prevention and risk factor modification. III.

Low implantation volume, comorbidities, male sexand implantation of constrained TKA identified as risk factors for septic revision in knee arthroplasty:A register-based study from the German Arthroplasty Registry.

Periprosthetic joint infection (PJI) is a major cause of revision surgery after total knee arthroplasty (TKA) and unicondylar knee arthroplasty (UKA). Patient- and hospital-related risk factors need to be assessed to prevent PJI. This study identifies influential factors and differences in infection rates between different implant types. Data were obtained from the German Arthroplasty Registry. Septic revisions were calculated using Kaplan-Meier estimates with septic revision surgery as the primary endpoint. Patients with constrained and unconstrained TKA or UKA were analysed using Holm's multiple log-rank test and Cox's proportional hazards ratio. The 300,998 cases of knee arthroplasty analysed included 254,144 (84.4%) unconstrained TKA, 9993 (3.3%) constrained TKA and 36,861 (12.3%) UKA with a maximum follow-up of 7 years. At 1 year, the PJI rate was 0.5% for UKA and 2.8% for TKA, whereas at 7 years, the PJI rate was 4.5% for UKA and 0.9% for TKA (p < 0.0001). The PJI rate significantly increased for constrained TKA compared to unconstrained TKA (p < 0.0001). The PJI rate was 2.0% for constrained TKA and 0.8% for unconstrained TKA at 1 year and 3.1% and 1.4% at 7 years. Implantation of a constrained TKA (hazard ratio [HR] = 2.55), male sex (HR = 1.84), increased Elixhauser score (HR = 1.18-1.56) and implant volume of less than 25 UKA per year (HR = 2.15) were identified as risk factors for revision surgery; an Elixhauser score of 0 (HR = 0.80) was found to be a preventive factor. Reduced implant volume and constrained knee arthroplasty are associated with a higher risk of PJI. Comorbidities (elevated Elixhauser score), male sex and low UKA implant volume have been identified as risk factors for PJI. Patients who meet these criteria require specific measures to prevent infection. Further research is required on the potential impact of prevention and risk factor modification. Level III.

Total knee arthroplasty: Quality assurance and improved longevity costs less

BackgroundThere is an accepted variation in the financial cost of total knee arthroplasty (TKA) implants but it is not known whether this cost is reflected by the evidence in support of their use. A cost analysis study was carried out to determine the total cost of consumables of a TKA, and whether this was related to the supporting evidence and survivorship data. MethodsIntra-operative data for all unilateral, cemented, primary TKA over a 13 month period at a high-volume Orthopaedic Centre was collected. Level of evidence for each model was taken from the Orthopaedic Data Evaluation Panel (ODEP) website, and data from the UK National Joint Registry was used to assign survivorship (failure rates). Correlation was calculated using the Spearman rank correlation (r). ResultsA total of 1301 TKA were performed at the study centre during the data collection period. The mean cost of consumables for a TKA with patella resurfacing (n = 816) was £1969.08 (range of £1061.46 and £5143.89), and without resurfacing (n = 485) was £1846.62 (range of £1118.98 and £4196.81). There was a negative correlation between price of implant and ODEP rating (r = −0.47), with increasing level of evidence being associated with a lower cost. There was a positive correlation between price of implant and rate of implant failure at the1-, 3- and 5-year time-points (r = 0.55, 0.44, 0.28 respectively), with increasing cost being associated with a higher failure rate. ConclusionHigher financial cost of TKA prostheses was associated with a weaker level of supporting evidence and a higher failure rate. The increased financial cost of new implants may be justified as more data and evidence becomes available to support an advantage in its use over currently established implants.

Use of semi-constrained total knee arthroplasty in gonarthrosis with collateral ligament insufficiency: Clinical and functional outcomes

IntroductionAchieving stability in total knee arthroplasty (TKA) is crucial for long-term implant survival. In cases of severe deformity or ligament laxity, constrained implants may be required. Traditionally, increasing constraint involved intramedullary stems. However, there are intermediary alternatives, including employing a constrained polyethylene insert without stems, thereby avoiding complications related to them. The study aims to evaluate our experience with a non-modular constrained (NMC) implant in primary TKA. Material and methodsWe conducted a retrospective review of the clinical and radiographic outcomes of 108 non-stemmed primary TKAs performed at our institution between 2013 and 2021 in patients with at least 10° deformity or 10mm ligament laxity. Data included demographics, preoperative and postoperative deformities, clinical outcomes and revision rates. ResultsA total of 103 patients (108 knees) with a mean age of 74 were followed up for a minimum of 2 years. The mean postoperative range of motion was 105°/0°. The median Oxford Knee Score, Knee Society Score and Knee Society Function Score were 43.5, 92 and 90, respectively. 17 knees had varus deformity (mean tibiofemoral angle of 2.7°), and 87 knees had excessive valgus deformity (mean tibiofemoral angle of 15.1°). The remaining 4 knees had a neutral alignment. The mean postoperative tibiofemoral angle was 6.8°. The overall revision rate was 6.5% (7 patients): 3 deep periprosthetic infections, 2 patellar dislocations, 1 stiffness and 1 aseptic loosening. ConclusionOur experience demonstrates favorable mid-term outcomes with the NMC implant, providing a safe alternative to stemmed implants in primary TKA, particularly in cases of severe deformity or ligament laxity.

Knee

The February 2024 Knee Roundup360 looks at: Do patients with hypoallergenic total knee arthroplasty implants for metal allergy do worse? An analysis of healthcare utilizations and patient-reported outcome measures; Defining a successful total knee arthroplasty; Incidence, microbiological studies, and factors associated with periprosthetic joint infection after total knee arthroplasty; A modified Delphi consensus statement on patellar instability; Cause for concern? Significant cement coverage in retrieved metaphyseal cones after revision total knee arthroplasty; Prevalence of post-traumatic osteoarthritis after anterior cruciate ligament injury remains high despite advances in surgical techniques; Cost-effectiveness of arthroscopic partial meniscectomy versus physical therapy for traumatic meniscal tears in patients aged under 45 years.

[Translated article] Study of femoral component malrotation as a cause of pain after total knee arthroplasty

IntroductionThe total knee arthroplasty (TKA) has been shown to be a successful and cost-benefit procedure in terms of pain improvement in patient with symptomatic knee osteoarthritis. However, almost a 20% of the patients are not satisfied with the result of the surgery. Material and methodWe have carried out a transversal unicentric cases controls study with clinical cases of the own hospital, obtained by a clinical records revision. A total of 160 patients with a TKA with at least 1 year of follow-up were selected. Demographic variables, functional scales (WOMAC and VAS) and rotation of the femoral component through the analysis of the images obtained by CT scan were collected. ResultsThe total was 133 patients that was divided in two groups. A control group and pain group. The Control group was made up of 70 patients with a mean age of 69.59 years (23 men and 47 women) and the pain group was made up of 63 patients with a mean age of 69.48 years (13 men and 50 women). We didn’t find difference regarding the analysis of the rotation of the femoral component. In addition, we were not found significant differences when applying a stratification by sex. And, the analysis of the malrotation of the femoral component, previously defining limits of value rotation considered as extreme, in any of the case did not show significant differences. ConclusionThe results of the study confirm that malrotation of the femoral component had no influence on the presence of pain at a minimum of one year of follow-up after TKA implantation.

Concept of coronal alignment in total knee arthroplasty

Total knee arthroplasty (TKA) is one of the most performed orthopedic surgeries worldwide. For many years, TKA implants were positioned according to a systematic approach known as mechanical alignment, which prioritized implant survival over the restoration of a more physiological knee. A high dissatisfaction rate of 20% after knee prosthesis has led to a rethinking of coronal alignment and a move towards a more personalized approach. With improved instrumentation, new-generation implants and the advent of robotic surgery, it is now possible to better restore the patient's anatomy, to position implants more accurately and to optimize ligament balance in extension and flexion. The aim is to achieve greater patient satisfaction and the perception of a normal or forgotten knee after surgery, while preserving the long-term survival of implants.

Periprosthetic Osteolysis (PPOL) Following Total Knee Arthroplasty (TKA) Treated with Hybrid Semiconstrained Prosthetic Revision: A Case Report

Periprosthetic Osteolysis (PPOL) is a significant complication following total knee arthroplasty (TKR), often leading to the need for surgical revisions. The precise etiology of aseptic loosening and PPOL remains unclear, but it is a growing problem due to an aging population and increased demand for TKR implants. A 70-year-old female presented with left knee pain following a fall. She had previously undergone left and right TKR due to osteoarthritis. X-rays revealed a dislodged femoral prosthesis component and bone lysis, indicating PPOL. The patient had poor bone quality and was at risk for further complications. Due to insurance limitations, a hybrid revision technique was chosen, preserving the tibial component and enhancing the femoral aspect with a new augmented implant. Periprosthetic osteolysis is complex, and treatment options can be limited by financial constraints, such as insurance coverage. In this case, the decision to perform an isolated femoral component revision was made to reduce costs, with close follow-up and rehabilitation planned to prevent complications. Hybrid revision requires careful monitoring. PPOL restoration necessitates immediate action and rehabilitation to promote optimal joint function. This case highlights the importance of balancing medical judgment and financial constraints, and the potential for hybrid revision in specific cases. It also emphasizes the need for a harmonious relationship between healthcare professionals and healthcare management for patient safety and satisfaction. Keywords: Complication; Hybrid revision; Periprosthetic osteolysis; Total knee arthroplasty.

Development of patient-specific 3D printed implants for total knee arthroplasty

Aim: Arthritis is a degenerative condition characterized by the progressive deterioration of the knee joint, leading to aches, rigidity, and decreased mobility. Total knee arthroplasty (TKA) surgery is performed to alleviate pain for restoring activity in these patients. TKA is carried out due to natural wear of the cartilage and meniscus or by sudden impact at the knee joint area. The surgical procedure involves careful planning, precise bone cuts, and insertion of artificial components made of metal alloys and high-density polyethylene. However, conventional manufacturing of customized knee implants involves time and cost. This work aims to present the application of three-dimensional (3D) printing for developing individualized knee implants for TKA and the challenges faced during it. Methods: Morphometry of the knee joint varies among different populations, including Indian and Western, which pose challenges during the surgery as accurate alignment and implant sizing are crucial for optimal outcomes. A female patient’s pre-surgery computed tomography (CT) scan is considered to identify the disease and to find region of interest (ROI) such as knee joint. Process involves converting scanned data to a file format for 3D printing via computer-aided design (CAD). Results: The patient’s CT scan data is processed to obtain the CAD models of knee joint and standard triangulation language (STL) file. Additional geometries and noise present near the region are removed to get ROI. Open loops and overlapping triangles are rectified in the STL file. Based on the morphometry of the bone, resection is done to obtain the CAD models of knee implants. 3D printing of the knee joint and implant prototypes is then obtained using fused deposition modelling (FDM). Line layers on the printed implant prototype are seen. Conclusions: Patient-specific 3D printed knee joint implant prototypes are successfully obtained using FDM. Challenges faced during the work are successfully worked out.

Satisfactory Short‑Term Outcomes of Condylar‑Constrained Knee Implants in Primary Total Knee Arthroplasty

Background: This research set out to assess the functional prognosis of constrained condylar knee (CCK) in patients with severe intraoperative instability and/or coronal deformity undergoing primary total knee arthroplasty (TKA). Materials and methods: A prospective cohort study including 25 knees (21 cases) who underwent primary TKA using CCK implants. Senior surgeon operated all patients during 2020/2021 and followed clinically and radiographically at three, six and 12 months and 2 years postoperative. All cases were implanted with a single-design, second-generation CCK implant with a mean follow-up of 2 years. Results: The current research involved 25 knees (21 patients) with mean age 62.8 ± 12.2 years and most of the included patients were females (19; 76%). Preoperatively, valgus was demonstrated in six patients (24%) while varus was reported in 19 patients (76%) with mean preoperative Valgus/Varus angle 24.4 ± 9.9. Mean preoperative Knee Society Score (KSS) was 13.2 ± 2.7, mean preoperative functional KSS was 23.8 ± 19.2 and mean preoperative range of movement (ROM) was 107 ± 19.2. After 6 months, mean values of KSS was 86.2 ± 7.59. After 1 year, 2 years &amp; over 2 years, mean values of KSS were 86.2 ± 7.6, 86.2 ± 7.5, 86.3 ± 7.7 respectively. Degree of change in KSS before and after the operation was 69.1 ± 20.9. Mean values of late functional KSS was 62.5 ± 23.3. Degree of change in functional KSS before and after the operation was 36.8 ± 19.1. Postoperative ROM mean value was 120 ± 6.9 with degree of change 12.8 ± 6.3. Three cases reported postoperative complications; one cellulitis, one anterior femoral notching and one peroneal nerve injury. KSS increased from baseline to early postoperative with statistically significant variances (p&lt; 0.001) however, no statistically significant changes were discovered in KSS from early postoperatively to 2 years of follow up. Conclusion: Primary TKA utilizing CCK implants in cases with severe coronal abnormalities and/or intraoperative instability had a good short-term survival rate, on par with less limited implants. With positive clinical and radiological results, CCK implants can be thought of as a good alternative in some instances. It is important to exercise caution while utilizing an elevated level of restraint, since less restricted implants should be preferred.

The sensitivity of the stiffness and thickness of a titanium inlay in a cementless PEEK femoral component to the micromotions and bone strain energy density

Polyetheretherketone (PEEK) has been proposed as alternative material for total knee arthroplasty implants due to its low stiffness, which may reduce stress-shielding. In cementless fixation, a proper primary fixation is required for long-term fixation. Previous research showed that the lower stiffness of a cementless PEEK femoral component results in larger micromotions at the implant-bone interface compared to a cobalt-chrome femoral component. A titanium inlay on the PEEK implant surface may improve the primary fixation while maintaining the favourable stiffness properties. Therefore, the effect of thickness and stiffness of a titanium inlay on the primary fixation and stress-shielding was investigated. A finite element model of the femur and femoral component was created with five titanium inlay variants. The micromotions and strain energy density (SED) were quantified as outcome measures. The distal thin – proximal thick variant showed the largest resulting micromotions (51.2 µm). Relative to the all-PEEK femoral component, the addition of a titanium inlay reduced the micromotions with 30 % to 40 % without considerably affecting the stress-shielding capacity (strain energy difference of 6 % to 10 %). Differences in micromotions (43.0–51.2 µm) and SED between the variants were relatively small. In conclusion, the addition of a titanium inlay could lead to a reduction of the micromotions without substantially affecting the SED distribution.

No clinical advantage with customized individually made implants over conventional off-the-shelf implants in total knee arthroplasty: a systematic review and meta-analysis.

Total knee arthroplasty (TKA) can be performed with either conventional off-the-shelf (OTS) or customized individually-made (CIM) implants. The evidence for CIM implants is limited and variable, and the aim of this review was to compare clinical and radiological outcomes between CIM and OTS implants. A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines. Studies reporting on clinical, radiological, or alignment outcomes for CIM and OTS implants were selected. The studies were appraised using the Methodical index for non-randomized studies tool. Twenty-three studies fulfilled the inclusion criteria. The studies comprised 2856 CIM and 1877 OTS TKAs. Revision rate was higher with CIM (5.9%) compared to OTS (3.7%) implants [OR 1.23(95% CI 0.69-2.18)]. Manipulation under anesthesia (MUA) was higher in CIM (2.2%) compared to OTS (1.1%) group [OR 2.95(95% CI 0.95-9.13)] and complications rate was higher in CIM (5%) vs. OTS (4.5%) [OR 1.45(95% CI 0.53-3.96)] but neither reached statistical significance. Length of stay was significantly shorter in CIM group 2.9days vs. 3.5days [MD -0.51(95% CI -0.82 to -0.20)]. Knee Society Score showed no difference between CIM and OTS groups for Knee 90.5 vs. 90.6 [MD -0.27(95% CI -4.27 to 3.73)] and Function 86.1 vs. 83.1 [MD 1.51(95% CI -3.69 to 6.70)]. CIM implants in TKA have theoretical benefits over OTS prostheses. However, in this present review, CIM implants were associated with higher revisions, MUA, and overall complication rates. There was no difference in outcome score and CIM implants did not improve overall target alignment; however, more CIM TKAs were found to be in the HKA target zone compared to OTS TKAs. The findings of this review do not support the general utilization of CIM over OTS implants in TKA.

Patient specific implants versus conventional implants in primary total knee arthroplasty: No significant difference in patient reported outcomes at 5 years

BackgroundPatient specific implants (PSI) represent a novel innovation aimed to improve patient satisfaction and function after total knee arthroplasty (TKA); however, longitudinal patient reported outcome measures (PROMs) for PSI are not well described. We sought to primarily evaluate PROMs of patients undergoing TKA with either PSI or off-the-shelf (OTS) implants at mid-term follow-up. MethodsA retrospective review was performed on a prospectively collected cohort of 43 primary, cruciate-retaining TKAs performed with PSI (n = 23) and OTS implants (n = 20) by a single surgeon. Patient demographics, operative characteristics, range of motion (ROM) return, reoperations, and outcomes [Patient-Reported Outcomes Measurement Information System (PROMIS) T-score, Knee Injury and Osteoarthritis outcome score (KOOS), and Knee Society Score-Function (KSS-F)] were compared. Mean follow-up was 5 years. ResultsTKA performed with either PSI and OTS implants demonstrated no difference in obtaining ROM by 3 months (extension 3° short of full extension vs. 0°, p = 0.16) or flexion (114° vs. 115°, p = 0.99) and final ROM was identical [0° extension to 120° flexion (p = 1)]. Although not significant (p = 0.42), 5 (22%) PSI TKA and 2 (10%) OTS implant patients required manipulation under anesthesia. KSS-F and PROMIS T-scores were higher in the PSI versus OTS TKA patients, respectively (90 vs. 73, p = 0.002; 51.6 vs. 44.5, p = 0.01). However, after multivariable analysis, none of these continuous outcome measures were significantly different (p = 0.28 for KSS and p = 0.45 for PROMIS T-score) between the groups. ConclusionIn a series of TKAs performed with PSI, no difference existed in postoperative ROM, reoperations, or patient-reported outcomes compared to OTS implants at 5 years. Surgeons may utilize the equivocal midterm results during TKA preoperative patient discussion of implant technologies.

Can artificial intelligence algorithms recognize knee arthroplasty implants from X-ray radiographs?

Aims: This study aimed to investigate the use of a convolutional neural network (CNN) deep learning approach to accurately identify total knee arthroplasty (TKA) implants from X-ray radiographs.&#x0D; Methods: This retrospective study employed a deep learning CNN system to analyze pre-revision and post-operative knee X-rays from TKA patients. We excluded cases involving unicondylar and revision knee replacements, as well as low-quality or unavailable X-ray images and those with other implants. Ten cruciate-retaining TKA replacement models were assessed from various manufacturers. The training set comprised 69% of the data, with the remaining 31% in the test set, augmented due to limited images. Evaluation metrics included accuracy and F1 score, and we developed the software in Python using the TensorFlow library for the CNN method. A computer scientist with AI expertise managed data processing and testing, calculating specificity, sensitivity, and accuracy to assess CNN performance.&#x0D; Results: In this study, a total of 282 AP and lateral X-rays from 141 patients were examined, encompassing 10 distinct knee prosthesis models from various manufacturers, each with varying X-ray counts. The CNN technique exhibited flawless accuracy, achieving a 100% identification rate for both the manufacturer and model of TKA across all 10 different models. Furthermore, the CNN method demonstrated exceptional specificity and sensitivity, consistently reaching 100% for each individual implant model.&#x0D; Conclusion: This study underscores the impressive capacity of deep learning AI algorithms to precisely identify knee arthroplasty implants from X-ray radiographs. It highlights AI’s ability to detect subtle changes imperceptible to humans, execute precise computations, and handle extensive data. The accurate recognition of knee replacement implants using AI algorithms prior to revision surgeries promises to enhance procedure efficiency and outcomes.

Distal Femur Morphological Discrepancy Compared with Total Knee Arthroplasty Implants in Indonesia

Distal Femur Morphological Discrepancy Compared with Total Knee Arthroplasty Implants in Indonesia