Total Knee Arthroplasty Implants Research Articles

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.

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 & 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< 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.
 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.
 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.
 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.

Preoperative predictors of implant size in patients undergoing total knee arthroplasty: a retrospective cohort study

BackgroundTraditionally, the size of total knee arthroplasty (TKA) components is predicted by preoperative radiographic templating, which is of limited accuracy. This study aimed to evaluate the role of demographic data and ankle volume in predicting implant size in TKA candidates.MethodsIn a retrospective study, 415 patients who underwent TKA at a single institution were included. The mean age of the patients was 67.5 ± 7.1 years. The mean BMI of the patients was 31.1 ± 4.7 kg/m2. TKA implants were Zimmer Biomet NexGen LPS-Flex Knee in all cases. The demographic data included age, sex, height, weight, BMI, ethnicity, and ankle volume. Ankle volume was assessed with the figure-of-eight method. Multivariate linear regression analysis was used for predicting factors of implant size.ResultsMultivariate linear regression analysis showed that the Sex (β:1.41, P < 0.001), height (β:0.058, P < 0.001), ankle volume (β:0.11, P < 0.001), and Age (β:0.017, P = 0.004) were significant predictors of tibial component size. Sex (β:0.89, P < 0.001), height (β:0.035, P < 0.001), and ankle volume(β:0.091, P < 0.001) were significant predictors of femoral component size in the multivariate analysis.ConclusionDemographic data, adjunct with the ankle volume, could provide a promising model for preoperative prediction of the size of tibial and femoral components in TKA candidates.

Rapid Estimation of Contact Stresses in Imageless Total Knee Arthroplasty

Total knee arthroplasty (TKA) is a surgical technique to replace damaged knee joints with artificial implants. Recently, the imageless TKA has brought a revolutionary improvement to the accuracy of implant placement and ease of surgical process. Based on key anatomical points on the knee, the software guides the surgeon during the TKA procedure. However, the number of revision surgeries is increasing due to malalignment caused by registration error, resulting in imbalanced contact stresses that lead to failure of the TKA. Conventional stress analysis methods involve time-consuming and computationally demanding finite element analysis (FEA). In this work, a machine-learning-based approach estimates the contact pressure on the TKA implants. The machine learning regression model has been trained using FEA data. The optimal preprocessing technique was confirmed by the data without preprocessing, data divided by model size, and data divided by model size and optimal angle. Extreme gradient boosting, random forest, and extra trees regression models were trained to determine the optimal approach. The proposed method estimates the contact stress instantly within 10 percent of the maximum error. This has resulted in a significant reduction in computational costs. The efficiency and reliability of the proposed work have been validated against the published literature.

Novel morphogenic knee implant delivers comparable mid-term outcomes as compared to conventional non-morphogenic implants.

Conventional total knee arthroplasty (C-TKA) implants have well-established mid- and long-term outcomes. The novel TKA (N-TKA) implants provide morphogenic implant components with smaller size increments to facilitate anatomical replication. The aim of the study is to evaluate if these advantages provides better clinical outcomes. Registry data prospectively collected within a single institution from 2014 to 2018 was reviewed and propensity score matching was performed to match C-TKA to N-TKA. 70 pairs of cruciate retaining (CR) TKA and 116 pairs of posterior stabilized (PS) TKA were identified. Range of motion, SF-36, Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS) and Oxford Knee Score (OKS) were assessed preoperatively, 6 and 24months postoperatively. Satisfaction was assessed 6 and 24months postoperatively. Independent T test was performed for parametric data, whereas Wilcoxon rank-sum analysis was performed for non-parametric data. Both C-TKA and N-TKA cohorts demonstrated statistically significant improvement for KSKS, KSFS, OKS and SF-36 at 6 and 24months postoperatively. C-TKA CR patients had better flexion at 6months as compared to N-TKA CR (108.7° versus 98.3°, respectively, p = 0.046). At 24months, there was no difference between C-TKA and N-TKA for range of motion, KSKS, KSFS, OKS and SF-36 PCS, regardless of insert type (p > 0.05). Both models showed great postoperative improvements in KSFS, KSKS, OKS and SF-36 and have comparable early and mid-term outcomes, suggesting that N-TKAs are suitable substitutes for C-TKA. Longer follow-up studies are required to evaluate the long-term outcomes of N-TKAs. lll.

Comparison of clinical outcomes among total knee arthroplasties using posterior-stabilized, cruciate-retaining, bi-cruciate substituting, bi-cruciate retaining designs: a systematic review and network meta-analysis.

Despite the advent of innovative knee prosthesis design, a consistent first-option knee implant design in total knee arthroplasty (TKA) remained unsettled. This study aimed to compare the clinical effects among posterior-stabilized (PS), cruciate-retaining (CR), bi-cruciate substituting (BCS), and bi-cruciate retaining designs for primary TKA. Electronic databases were systematically searched to identify eligible randomized controlled trials (RCTs) and cohort studies from inception up to July 30, 2021. The primary outcomes were the range of knee motion (ROM), and the secondary outcomes were the patient-reported outcome measures (PROMs) and complication and revision rates. Confidence in evidence was assessed using Confidence in Network Meta-Analysis. The Bayesian network meta-analysis was performed for synthesis. A total of 15 RCTs and 18 cohort studies involving 3520 knees were included. The heterogeneity and inconsistency were acceptable. There was a significant difference in ROM at the early follow-up when PS was compared with CR (mean difference [MD] = 3.17, 95% confidence interval [CI] 0.07, 7.18) and BCS was compared with CR (MD = 9.69, 95% CI 2.18, 17.51). But at the long-term follow-up, there was no significant difference in ROM in any one knee implant compared with the others. No significant increase was found in the PROMs and complication and revision rates at the final follow-up time. At early follow-up after TKA, PS and BCS knee implants significantly outperform the CR knee implant in ROM. But in the long run, the available evidence suggests different knee prostheses could make no difference in clinical outcomes after TKA with extended follow-up.

Do Patients With Hypoallergenic Total Knee Arthroplasty Implants for Metal Allergy Do Worse? An Analysis of Health Care Utilizations and Patient-Reported Outcome Measures

BackgroundMetal allergy is a rare and controversial cause of implant failure and poor outcomes following total knee arthroplasty (TKA). Few studies have investigated clinical and patient-reported outcome measures (PROMs) in patients treated with hypoallergenic implants. This investigation aimed to compare: (1) health care utilizations (eg, hospital length of stay, 90-day readmission rate, and incidence of nonhome discharge) and (2) 1-year PROMs between patients who received hypoallergenic and standard TKA implants. MethodsThis was a retrospective review of prospectively collected data from patients who underwent primary TKA between 2018 and 2019. Propensity score matching (3:1) was used to compare standard TKA patients with those who received hypoallergenic TKA implants, respectively. Knee injury and Osteoarthritis Outcome Score (KOOS) pain, KOOS Physical function Shortform (PS), and Veterans RAND 12-Item Health Survey Mental Component Score were collected preoperatively and at 1-year. After matching, 190 hypoallergenic and 570 standard TKAs were analyzed. ResultsNo differences were observed in length of stay (P = .98), 90-day readmission (P = .89), and nonhome discharge (P = .82). Additionally, there was no significant difference in change from preoperative to 1-year PROMs (KOOS pain, P = .97; KOOS PS, P = .88; Veterans RAND 12-Item Health Survey Mental Component Score, P = .28). Patient-reported satisfaction was similar at 1-year (P = .23). Patients achieved similar rates of Patient Acceptable Symptom State (PASS) and minimal clinically important difference (MCID) for KOOS pain (PASS, P = .77; MCID, P = .33) and KOOS PS (PASS, P = .44; MCID, P = .65). ConclusionPatients treated with hypoallergenic TKA implants for suspected metal allergy had similar outcomes compared to patients who had standard implants and no metal allergy.

Patellofemoral Arthroplasty.

Patellofemoral arthroplasty (PFA) as a treatment option for isolated patellofemoral disease continues to evolve. Enhancement in patient selection, surgical technique, implant design, and technology has led to improved short-term and midterm outcomes. Furthermore, in the setting of a younger patient with isolated patellofemoral arthritis, PFA represents an option for improved function with faster recovery times, bone preservation, maintenance of ligamentous proprioception, and the ability to delay total knee arthroplasty (TKA). The most common reason for revising PFA to a TKA is progression of tibiofemoral arthritis. In general, conversion of PFA to TKA leads to successful outcomes with minimal bone loss and the ability to use primary TKA implants and instrumentation. PFA seems to be a cost-effective alternative to TKA in appropriately selected patients with 5-, 10-PFA survivorships of 91.7% and 83.3%, respectively, and an annual revision rate of 2.18%; however, more long-term clinical studies are needed to determine how new designs and technologies affect patient outcomes and implant performance.

Short-term clinical and radiological comparisons between two Medial Pivot Total Knee Arthroplasty implants with different geometries.

Different total knee arthroplasty (TKA) implants were created for the treatment of severe symptomatic gonarthrosis and Medial Pivot TKA (MP TKA) seem to reproduce the normal kinematics of the knee. We compare two different prosthetic designs of MP TKA in order to identify whether there is a difference between the two in terms of degree of patient satisfaction. Methods: A total of 89 patients were analyzed. A group of 46 patients who benefited from a TKA with the Evolution® prosthesis and one of 43 patients who received a TKA with the Persona® prosthesis. KSS, OKS, FJS and the ROM were analyzed at follow up. The values of KSS and OKS were similar between the two groups (p>0,05). Our statistical analysis revealed a statistically significant increase (p <0.05) in ROM in the Persona® group and in FJS in the Evolution® group. No radiolucent lines were observed in both groups at the radiological final follow-up. Conclusions: MP TKA models analysed are a valuable tool to achieve satisfactory clinical outcomes. This study demonstrates that the FJS is an important score for the evaluation of patient's satisfaction: a ROM's limitation can be accepted by the patient in exchange for a more natural perceived knee.

Restoring Anatomical Features in Primary Total Knee Arthroplasty.

Today, the number of people affected by gonarthrosis symptoms is increasing proportionally. Total knee arthroplasty (TKA) is a successful intervention that aims to reduce pain and restore knee function. However, studies have shown that active young patients still have limitations in performing activities such as skiing, golfing, surfing, and dancing. Over the last few years, total knee arthroplasty has undergone significant changes. Most of the modern TKA implants are designed to reproduce the normal biomechanics of the knee joint, mimicking the physiological pattern with greater compliance in the medial compartment between the tibial insert and femoral condyle and less congruence on the lateral side. Unfortunately, functional outcomes are compromised in approximately half of TKA patients. This loss may be caused by the abnormal kinematics and inherent instability of many contemporary implants. The proper alignment of the femoral component during TKA is a crucial step that influences postoperative results. The position of the femoral component in the axial plane is responsible for flexion stability, knee joint kinematics, flexion alignment, and patellar tracking. The main goal when choosing a type of prosthesis is to achieve an adequate recovery that leads to an improvement in mobility and an increase in the efficiency of the quadriceps.

RWD68 Early Optimal Recovery As a Composite Outcome to Measure Value of Care in Patients Undergoing Primary Total Knee Arthroplasty with a New Implant Design

Many adjustments have been made to the design of Total Knee Arthroplasty (TKA) implants to improve outcomes. This study aims to investigate the impact of an innovative TKA implant design on a new composite outcome “early optimal recovery (EOR)”, an overall measure for value of care which combines early clinical outcomes and healthcare resource utilizations (HRU).