Knee Arthroplasty Implants Research Articles

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.

CT Morphometric Analysis of the Medial Femoral Condyle in an Indian Population: A Comparative Study of Unicompartmental Knee Arthroplasty Implants.

Purpose The objective of this study was to evaluate the compatibility of the medial femoral condyle (MFC) dimensions in the Indian population with the standard femoral components of three commercially available unicompartmental knee arthroplasty (UKA) implants. Methods This analytical study utilized CTmorphometric data from 100 consecutive non-arthritic adult knees. MFC dimensions were measured to assess their compatibility with UKA prostheses. The proportion of knees that could be optimally replaced using three commercially available UKA femoral implant systems, Link, DePuy, and Smith & Nephew, was calculated. Results The study cohort comprised 56 males and 44 females, with a mean age of 43.28 ± 10.53 years. For the Link implant system, the 'small' size was the most compatible, fitting 43% (43) of the patients, followed by 'medium-small' (35%, n = 35) and 'medium' (16%, n = 16). For the DePuy Sigma Uni implant, the best fit was 'size 1' for 38% (38) of the patients, followed by 'size 3' (25%, n = 25), 'size 4' (13%, n = 13), 'size 2' (10%, n = 10), and 'size 5' (2%, n = 2). In the case of the Smith & Nephew system, 'size 2' was the best fit for 30% (30) of the knees, followed by 'size 3' (27%, n = 27), 'size 4' (15%, n = 15), 'size 1' (12%, n = 12), and 'size 5' (8%, n = 8). Overhang of the femoral component, due to the MFC being smaller than the smallest available femoral component size, was observed in 6% (6) of knees with Link implants, 12% (12) with DePuy implants, and 8% (8) with Smith & Nephew implants. Conclusion The findings indicate that the most suitable femoral component sizes for Indian knees were 'small' in the Link system (43%, n = 43), 'size 1' in the DePuy system (38%, n = 38), and 'size 2' in the Smith & Nephew system (30%, n = 30). The results suggest a need for implant manufacturers to consider developing customized components tailored to the Indian population to enhance fit and minimize the occurrence of femoral component overhang.

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.

The treatment of bacterial biofilms cultivated on knee arthroplasty implants using the bioelectric effect.

Introduction: The formation of bacterial biofilms on knee arthroplasty implants can have catastrophic consequences. The aim of this study was to analyze the effectiveness of the bioelectric effect in the elimination of bacterial biofilms on cultivated knee arthroplasty implants. Methods: A novel device was designed to deliver a bioelectric effect on the surface of knee arthroplasty implants. 4-femoral prosthetic implants were cultivated with a staphylococcus aureus inoculum for 15days. The components were divided into four different groups: A (not treated), B (normal saline 20-minutes), C (bioelectric effect 10-minutes), D (bioelectric effect 20-minutes). The implants were sonicated, and the detached colonies were quantified as the number of colony-forming unit (CFUs). The implants were sterilised and the process was repeated in a standardized manner four more times, to obtain a total of five samples per group. Results: The number of the CFUs after a 10-minute exposure to the bioelectric effect was of 208.2 ± 240.4, compared with 6,041.6 ± 2010.7 CFUs in group A, representing a decrease of 96.5% ± 4.3 (p = 0.004). And a diminution of 91.8% ± 7.9 compared with 2,051.0 ± 1,364.0 CFUs in group B (p = 0.109). The number of bacterial colonies after a 20-minute exposure to the bioelectric effect was 70 ± 126.7 CFUs, representing a decrease of 98.9% ± 1.9 (p = 0.000) compared with group A. And a decrease of 97.8% ± 3.0 (p = 0.019) compared with group B. Conclusions: The bioelectric effect was effective in the elimination of bacterial biofilm from knee arthroplasty implants. This method could be used in the future as part of conventional surgical procedures.

Target Organs of Metals Released from Metal-on-Polyethylene Knee and Hip Arthroplasty Implants: Implications for Tissue Metal Profiles

Target Organs of Metals Released from Metal-on-Polyethylene Knee and Hip Arthroplasty Implants: Implications for Tissue Metal Profiles

Valgus stress knee radiographs accurately anticipate the bone resection in medial unicompartmental knee arthroplasty: Protocol validation using an image-based robotic system.

The objective of this study was to describe a planning method for medial unicompartmental knee arthroplasty (UKA) implantation using preoperative stress radiographs to measure the thickness of tibial and femoral bone resectionsand to validate this method with data from an image-based robotic surgery system. Having such method for preoperative planning would be of interest for surgeons performing UKA in order to anticipate optimal bone resection on both tibia and femoral sides. A new planning method for medial UKA based on valgus stress knee radiographs validated it with an image-based robotic surgery system (Restoris MCK, MAKO®, Stryker Corporation) was proposed. This retrospective study involved radiographic measurements of 76 patients who underwent image-based robotic medial UKA between April 2022 and February 2023. Preoperative anteroposterior stress radiographs of the knee were used to simulate UKA implantation. The UKA technique was based on Cartier's angle and aimed at restoring the joint line. The total dimension measured was 14 mm (8 mm for minimal tibial component and polyethylene insert + 4 mm for femoral component + 2 mm for safety laxity). Bone resections were measured in the preoperative valgus stress radiographs and then against the intraoperative bone resection data provided by the robotic system. Inter- and intra-observer reliability was assessed using 25 measurements. The mean planned tibial resection measured in the radiographs was 4.3 ± 0.4 [2.9-5.8], while the mean robotic resection was 4.2 ± 0.5 [2.7-5.8] (mean difference = 0.15 mm, 95% confidence interval [CI] [-0.27 to 0.57]). There was a strong correlation between these two values (Pearson's rank R = 0.79, p < 0.001). Intra- and inter-observer reliability were also very strong (Pearson's rank R = 0.91, p < 0.001, and Pearson's rank R = 0.82, p < 0.001, respectively). The mean planned femoral bone resection measured in the radiographs was 2.7 ± 0.7 mm [1-4.5], while the mean robotic resection was 2.5 ± 0.9 [1-5] (mean difference = 0.21 mm, 95% CI [-0.66 to 1.08]). There was a strong correlation between these two values (Pearson's rank R = 0.82, p < 0.001). Intra- and inter-observer reliability were also strong (Pearson's rank R = 0.88, p < 0.001, and Pearson's rank R = 0.84, p < 0.001, respectively). This study describes and validates with robotic information a simple and reproducible preoperative planning method to determine femoral and tibial bone resection for medial UKA implantation using antero-posterior valgus stress knee radiographs, leaving a medial safety laxity of 2 mm. It represents a very valuable contribution to the understanding of UKA principles, which can serve to extend its indications and increase reproducibility of the surgical technique. III. Retrospective cohort study.

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.

Dealing with early complications in unicondylar knee arthroplasty-what works, what does not?

Complications in the early postoperative period following the implantation of aunicondylar knee arthroplasty (UKA) are both rare and rarely described in the literature. Often, only small case series or individual case reports are available. In this article, the most common complications of periprosthetic infection, periprosthetic tibial fracture, inlay dislocation and intra-articular cement residue in (loose bone cement body) are described and recommendations for conservative and surgical treatment are presented, including case examples. Ideally, surgical errors or an infection should be recognized at an early stage and revised as soon as possible.

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.

Navigation and robotics-current status and future implications

Both navigation systems and robotics enable greater precision in the implantation of an artificial knee joint. However, they do not improve clinical outcomes. We hypothesized that although implantation of atotal knee arthroplasty results in reconstruction of the alignment in the coronal plane, the variable rotational tibial and variable translational femoral and tibial component positioning lead to achange in the remaining alignment parameters of the lower extremity. However, these parameters could be determined using anavigation system or robot and could represent future implications for these systems. The kinematics and the position between femur and tibia before and after implantation of atotal knee arthroplasty were determined using anavigation system in nine healthy knee joints of Thiel-fixed whole-body cadavers. After arthroplasty, there was no change in the natural coronal alignment. In extension and the early degrees of flexion, the rotational position of the femur relative to the tibia was altered. This also led to achange in the positioning of the medial and lateral epicondyle in relation to the tibia; while both epicondyles were positioned more laterally in relation to the tibia after arthroplasty, the lateral epicondyle was significantly more lateral in relation to the tibia up to 20° of flexion. Following arthroplasty of aknee joint using the established technique, agood reconstruction of the coronal alignment was achieved with simultaneous changes in the alignment in both the rotational and translational directions between the femur and tibia. Using navigation as well as robotics, we would be able to quantify all alignment parameters and could achieve an alignment of the components or areconstruction of the overall alignment in all six degrees of freedom. We might also be able to achieve aclinical advantage or increase the service life even further.

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.

Kinematic Performance of Medial Pivot Total Knee Arthroplasty

BackgroundTotal knee arthroplasty (TKA) implants have continued to evolve to accommodate new understandings of knee mechanics. The medial-pivot implant is a newer design, which is intended to limit anterior-posterior translation in the medial compartment while allowing lateral compartment translation. However, evidence for a generalized medial-pivot characteristic across all activities is limited. The purpose of the study was to quantify and compare in vivo knee joint kinematics using high-speed stereo radiography during activities of daily living in patients who have undergone a TKA with a cruciate sacrificing medial-pivot implant to age-matched and sex-matched native controls. MethodsFifteen participants (7 patients, 4 women, mean age 70 years and 8 nonsymptomatic controls, 4 women, mean age 64 years) performed 6 functional tasks in high-speed stereo radiography: deep-knee lunge, chair rise, step down, gait, gait with 90° turn, and seated knee extension. Translational differences between groups (surgical versus control) were assessed for the medial and lateral condyle, while pivot location was normalized to subject-specific tibial plateau geometry. ResultsThe surgical cohort displayed a more constrained medial condyle that provided greater stability of the medial compartment and did not result in the paradoxical anterior translation at mid-flexion angles during weight-bearing activities, but was associated with less condylar translation than native knees. Additionally, the transverse tibial pivot location occurs most commonly in the middle third of the tibial plateau and secondarily on the medial third. ConclusionsSome variability in pivot location occurs between activities and is more in nonsymptomatic, native knee controls.

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.

Clinical investigations to evaluate high-risk orthopaedic devices: a systematic review of the peer-reviewed medical literature

Purpose The objective of this systematic review was to give an overview of clinical investigations regarding hip and knee arthroplasty implants published in peer-reviewed scientific medical journals before entry into force of the EU Medical Device Regulation in May 2021. Methods We systematically reviewed the medical literature for a random selection of hip and knee implants to identify all peer-reviewed clinical investigations published within 10 years before and up to 20 years after regulatory approval. We report study characteristics, methodologies, outcomes, measures to prevent bias, and timing of clinical investigations of 30 current implants. The review process was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results We identified 2912 publications and finally included 151 papers published between 1995 and 2021 (63 on hip stems, 34 on hip cups, and 54 on knee systems). We identified no clinical studies published before Conformité Européene (CE)-marking for any selected device, and no studies even up to 20 years after CE-marking in one-quarter of devices. There were very few randomized controlled trials, and registry-based studies generally had larger sample sizes and better methodology. Conclusion The peer-reviewed literature alone is insufficient as a source of clinical investigations of these high-risk devices intended for life-long use. A more systematic, efficient, and faster way to evaluate safety and performance is necessary. Using a phased introduction approach, nesting comparative studies of observational and experimental design in existing registries, increasing the use of benefit measures, and accelerating surrogate outcomes research will help to minimize risks and maximize benefits.

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.

Condylar constrained and rotating hinged implants in revision knee arthroplasty show similar survivorship and clinical outcome: a systematic review and meta-analysis.

In revision total knee arthroplasty (TKA) ligament instability and bone defects might require more constraint implants such as a condylar constrained knee (CCK) or rotating hinged knee (RHK). When both implants are suitable, the choice remains controversial. The purpose of this systematic review and meta-analysis was to compare the survivorship and clinical outcome between CCK and RHK in revision TKA. Systematic literature research was performed. Studies analysing the clinical outcome and/or survivorship of CCK and/or RHK in revision TKA were included. Clinical outcomes included the Knee Society Score, both clinical (KSCS) and functional (KSFS), range of motion (ROM) and reoperations. Survival was defined as the time free from removal or revision of the femoral and/or tibial component. A total of 40 articles analysing 4.555 knees were included. Survival did not differ between RHK and CCK implants (p = 0.6058), with, respectively, 91.6% and 89.8% survival after 5years. Postoperative KSCS and KSFS were, respectively, 79.2 (SD 10.7) and 61.1 (SD 21.8) for the CCK group. Similar scores were noted for the RHK group with a KSCS of 80.2 (SD 14.1) and KSFS of 58.5 (SD 17.3). Postoperative ROM was similar for CCK (105.3°, SD 17.1°) and RHK patients (104.1°, SD 16.9°). This meta-analysis revealed that both survivorship and clinical outcome are similar for CCK and RHK patients for whom both designs are technically suitable and indicated. IV.

Metal ion release after hip resurfacing arthroplasty and knee arthroplasty: a retrospective study of one hundred ninety-five cases.

Hip arthroplasty with metal-on-metal bearings like hip resurfacing results in the release of metallic ions. In parallel, like every metallic implant, knee arthroplasty implants undergo passive corrosion. We analyzed blood levels of cobalt and chromium ions in patients who have a hip resurfacing arthroplasty and compared them to patients who have undergone knee arthroplasty at a minimum follow-up of one year. The hypothesis was that there is no difference in the ion release between hip resurfacing and knee arthroplasty. Sixty-three patients who underwent knee arthroplasty were compared to a cohort of 132 patients who underwent hip resurfacing. The blood levels of cobalt and chromium ions were determined preoperatively and at six and 12 months postoperatively and then compared between groups. We analyzed the relationship between ion release and the change in clinical outcome scores (Harris Hip score, Oxford Hip score, Merle D'Aubigné Postel score, Oxford Knee score, International Knee Society score), the BMI, sex, physical activity, implant size and inclination of the acetabular implant (hip resurfacing patients only). Mixed linear models were used to assess the changes in ion blood levels over time. The cobalt blood levels were higher in the first 6 months in the resurfacing group (0.87 ug/L vs 0.67 ug/L; p = 0.011), while it was higher in the knee arthroplasty group at 12 months (1.20 ug/L vs 1.41 ug/L; p = 0.0008). There were no significant differences in chromium levels during the follow-up period. The increase in metal ion release after knee arthroplasty is as high as after hip resurfacing at the oneyear follow-up. The monitoring of this parameter probably should not be recommended in case of good clinicals outcomes.