scholarly journals Using MRI Measurement to Improve Accuracy of Femoral Component Sizing in Oxford Unicompartmental Knee Arthroplasty

2021 ◽  
Vol 10 (18) ◽  
pp. 4284
Author(s):  
Cheng-Pang Yang ◽  
Ying-Chieh Lai ◽  
Chen-Te Wu ◽  
Kung-Tseng Hung ◽  
Yi-Sheng Chan ◽  
...  
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Measurement Method ◽  
Lateral View ◽  
Phase Iii ◽  
Component Size ◽  
Unicompartmental Knee ◽  
Significant Difference ◽  
Magnetic Resonance Imaging Mri

Unicompartmental knee arthroplasty (UKA) can achieve better kinematics and faster recovery than total knee arthroplasty. The Phase III Oxford UKA system has five sizes of femoral components to approximate the normal knee geometry. However, these different sizes may also induce problems, such as the misselection of component size. Different criteria have been proposed to predict the ideal size preoperatively. However, no single method can be applied universally. Therefore, this study aimed to develop a preoperative measurement using knee magnetic resonance imaging (MRI) to predict femoral component size. A total of 68 patients who underwent UKA were investigated from June 2019 to April 2020. 16 knees using a different MRI protocol were excluded. We developed an MRI measurement method to determine femoral size instead of gender- and height-based methods. The accuracy of different methods was compared using postoperative true lateral view radiographs. Three different kinds of gender- and height-based criteria, preoperative templating and intraoperative spoon measurement were compared. The accuracy of MRI measurement was 90.3%. Therefore, a significant difference was found between MRI measurements and all other methods, such as templating or gender- and height-based methods. In conclusion, the MRI measurement method can be concluded to accurately predict femoral component size in UKA. This method could be used regardless of different ethnic groups, individual knee geometry, or soft tissue tension.

scholarly journals Does new instrument for Oxford unicompartmental knee arthroplasty improve short-term clinical outcome and component alignment? A meta-analysis

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiao Wei Sun ◽  
Fei Fan Lu ◽  
Kun Zou ◽  
Mao Hong ◽  
Qi Dong Zhang ◽  
...  
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Revision Rate ◽  
Meta Analysis ◽  
Phase Iii ◽  
Cochrane Library ◽  
Radiological Assessment ◽  
Short Term ◽  
Unicompartmental Knee

Abstract Background The Microplasty (MP) instrumentation designed for the Phase III Oxford mobile-bearing unicompartmental knee arthroplasty (UKA) system is considered a better option to achieve more accurate component positioning and alignment. In the present study, we focused on short-term clinical and radiological outcomes to determine whether the MP instrumentation can reduce the short-term revision rate and occurrence of outliers of metallic components. Methods The literature in PubMed, Embase, the Cochrane Library, and Web of Science was searched up to May 2020. Studies were scrutinized by two independent authors, and the revision rate, complication spectrum, and radiological assessment with outlier rates were specifically analyzed. RevMan 5.3 was used for the statistical analysis. Results Seven studies were included in the meta-analysis. Four studies reported both clinical and radiological outcomes, two reported only radiological outcomes, and one reported only clinical outcomes. The pooled analysis showed that the revision rate in the MP instrumentation group was 0.866 per 100 component years, while that in the control group was 1.124 (odds ratio, 0.77; p < 0.05). The subgroup analysis of the bearing dislocation rate showed a significantly greater reduction in the Korean population than in the populations of other countries (p < 0.05). The radiological assessment showed that the alignment of the femoral component was significantly improved (p < 0.05), while that of the tibial component was not (p > 0.05). Conclusion The newly developed MP instrumentation for Oxford UKA significantly reduced the revision rate of this treatment. The positioning of the femoral component was also proven to be better by radiological assessments.

Robot-Assisted Unicompartmental Knee Arthroplasty: Increasing Surgical Accuracy? A Cadaveric Study

2019 ◽  
Author(s):  
Magaly Iñiguez ◽  
Roberto Negrín ◽  
Jaime Duboy ◽  
Nicolás O. Reyes ◽  
Rodrigo Díaz
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Functional Results ◽  
Tibial Slope ◽  
Clinical Results ◽  
Robot Assisted ◽  
Post Surgery ◽  
Unicompartmental Knee ◽  
Significant Difference

AbstractUnicompartmental knee arthroplasty (UKA) represents 10% of knee arthroplasties. Advantages are better functional results, quicker recovery, shorter hospitalization time, and lower blood loss, among others. However, revision rates are larger than total knee arthroplasty. Among the most important factors that explain this are the implant position and alignment, and the correct surgical indication. Greater accuracy in the implant placement may improve clinical results and increase the rate of implant survival. The objective of this study is to evaluate the precision of the Navio robot-assisted system in the position and alignment of medial UKA compared with the conventional technique. This is an experimental pilot study. Twenty-six cadaveric models were randomized into 2 groups: Robot-Assisted surgery (R) and Conventional Surgery (C). Radiological study was performed pre- and post-surgery, evaluating the medial distal femoral angle (MDFA), medial proximal tibial angle (MPTA), tibial slope, tibiofemoral angle (TFA), sagittal femoral angle (SFA), and size of the femoral and tibial components. The main result measurement was the change in postoperative angulation. The results of this study are MDFA median of 1.07° (0.19–4.5) for group R and 0.12° (0.03–10.4) with a significant difference in variances; a Welch t-test of p = 0.013; and an MPTA of 1.28° (0.05–5.87) for R and 1.3°(0.08–14.1) for C with significantly different variances (p = 0.0064). Size of the femoral component has a difference of p < 0.05 between groups. No differences for dispersion of TFA nor for the size of the tibial component were observed. In conclusion, using robot-assisted UKA allows for greater accuracy in the positioning of the implants and in the prediction of the size of the femoral component.

scholarly journals Radiographic and Clinical Evolution of the Oxford Unicompartmental Knee Arthroplasty

2021 ◽  
Author(s):  
Riccardo D'Ambrosi ◽  
Manuel J. de S.V. da Silva ◽  
João L. M. Moura ◽  
Ilaria Mariani ◽  
Luca D. Serrao ◽  
...  
Keyword(s):  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Oxford Knee Score ◽  
Tibial Slope ◽  
Phase Iii ◽  
Positive Correlation ◽  
Tibial Resection ◽  
Unicompartmental Knee ◽  
Significant Difference ◽  
Oxford Unicompartmental Knee Arthroplasty

AbstractThe aim of the study is to evaluate whether the use of the new instrumentation Microplasty (MP) improves component positioning and the reliability of the surgical technique, reducing the implant outliers from the recommended range and providing a more accurate resection, while avoiding insufficient or excessive tibial resection and clinical scores. We prospectively analyzed clinical and radiographic outcomes of three consecutive cohorts for a total of 227 implants at a minimum follow-up of 36 months. The first cohort consisted of 67 Oxford unicompartmental knee arthroplasty (OUKA), using the phase III (Ph-III). The second cohort consisted of 136 OUKA, with the MP instrumentation. The third cohort consisted of 24 hypoallergenic OUKA, using the MP instrumentation (TiNbN). Postoperative alignment of the knee in the coronal and sagittal plane was measured using radiographs. No clinical differences were found among the three groups (p > 0.05). A significant difference was found on the slope between Ph-III and MP (p = 0.0005). Moreover, a significant difference was found in tibial angle and in tibial slope in arthroplasty with femoral size small (S), compared with size medium (M) or large (Ly) (tibia varus/valugs angle: p = 0.0484; tibial slope: p = 0.04). Similar results were found between small (AA, A, B) tibial size and large (C, D, E, F) tibial size for tibial varus/valgus (p = 0.03) angle and tibial slope (p = 0.003). A significant difference was found between Ph-III and MP in tibial slope in patients with body mass index (BMI) ≥25 kg/m2 (p = 0.0003). A positive correlation was noted between the femoral and tibial sizes and the tibial angle and the slope, and a negative correlation between weight and the tibial slope; furthermore, a positive correlation was found between Oxford knee score and radiographic angles. The MP instrumentation seems to be effective in determining the tibial cut and, particularly, improving the tibial slope, compared with Ph-III. The tibial slope is directly affected by the weight and measurements of the components, regardless of the instruments or the number of pegs, while clinical outcomes are correlated with implant position. This prospective comparative study reflects level of evidence II.

scholarly journals Oxford Phase 3 Unicompartmental Knee Arthroplasty in Thailand: Distribution of Prosthetic Size and Height Based on Gender Distribution of Femoral Component Size

2021 ◽  
Author(s):  
Pakpoom Ruangsomboon ◽  
Jirayu Paugchawee ◽  
Rapeepat Narkbunnam ◽  
Keerati Chareancholvanich ◽  
Chaturong Pornrattanamaneewong
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Statistical Significance ◽  
Patient Characteristics ◽  
Continuous Variables ◽  
Phase 3 ◽  
Gender Distribution ◽  
Component Size ◽  
Unicompartmental Knee

Abstract Introduction: Survivorship of Oxford phase 3 unicompartmental knee arthroplasty (OUKA) is strongly influenced by the size of the femoral component (Fc) and the tibial component (Tc) that are selected. The distribution of prosthetic size, and guidelines to determine the ideal Fc size have been mainly studied in Western population. The aim of this study was to determine the distribution of OUKA prosthetic size, and to investigate the factors that significantly influence the selection of Fc size in Thai patients.Methods: This retrospective study included 773 OUKA that were performed using Oxford Microplasty® Instrumentation during 2003-2019. Patient age, gender, side, body weight (BW), height, body mass index (BMI), size of femoral and tibial components, and the matching between components were recorded. The distribution of implant size and their matching was analyzed. Patient characteristics were compared among the Fc sizes. Area under the receiver operating characteristic (AuROC) curve was calculated to measure the performance of significant continuous variables for determining Fc size.Results: The distribution of Fc size was extra-small (XS) 6.5%, small (S) 65.7%, medium (M) 20.6%, large (L) 7.2%, and extra-large (XL) 0%. The distribution of Tc size included AA 20.2%, A 31.6%, B 24.3%, C 16.3%, D 6.0%, E 1.7%, and F 0%. The most common Fc and Tc sizes in females was S and A, respectively, and in males M and C, respectively. The most common matching pattern used in females and males was S-A (32.3%) and M-C (27.6%), respectively. Concerning factors that influence Fc prediction, we found significant differences in gender, BW, height, and BMI among the Fc sizes. After calculating the AuROC for BW, height, and BMI, we found height to have the highest AuROC with statistical significance. Height based on gender distribution was also analyzed.Conclusion: In Thai patients, the predominant size of Fc was S for females, and M for males. The predominant size of Tc was A for females, and C for males. The most common matching pattern was S-A for females, and M-C for males. Gender and height were identified as the factors that most strongly influence the prediction of Fc size.

Patient-acceptable symptom state for reporting outcomes following unicompartmental knee arthroplasty

2021 ◽  
Vol 103-B (8) ◽  
pp. 1367-1372
Author(s):  
Kevin D. Plancher ◽  
Jasmine E. Brite ◽  
Karen K. Briggs ◽  
Stephanie C. Petterson
Keyword(s):  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Cruciate Ligament ◽  
Intact Group ◽  
Unicompartmental Knee ◽  
Significant Difference ◽  
Patient Acceptable Symptom State ◽  
Acl Deficient ◽  
Deficient Group

Aims The patient-acceptable symptom state (PASS) is a level of wellbeing, which is measured by the patient. The aim of this study was to determine if the proportion of patients who achieved an acceptable level of function (PASS) after medial unicompartmental knee arthroplasty (UKA) was different based on the status of the anterior cruciate ligament (ACL) at the time of surgery. Methods A total of 114 patients who underwent UKA for isolated medial osteoarthritis (OA) of the knee were included in the study. Their mean age was 65 years (SD 10). No patient underwent a bilateral procedure. Those who had undergone ACL reconstruction during the previous five years were excluded. The Knee injury Osteoarthritis Outcome Score Activities of Daily Living (KOOS ADL) function score was used as the primary outcome measure with a PASS of 87.5, as described for total knee arthroplasty (TKA). Patients completed all other KOOS subscales, Lysholm score, the Western Ontario and McMaster Universities Osteoarthritis Index, and the Veterans Rand 12-item health survey score. Failure was defined as conversion to TKA. Results Survivorship at ten years was 97% in both the ACL-deficient and ACL-intact groups. The mean survival was 16.1 years (95% confidence interval (CI) 15.3 to 16.8) for the ACL-deficient group and 15.6 years (95% CI 14.8 to 16.361) for the ACL-intact group (p = 0.878). At a mean of nine years (SD 3.5) in the ACL-deficient group, 32 patients (87%) reached the PASS for the KOOS ADL. In the ACL-intact group, at a mean of 8.6 years (SD 3) follow-up, 63 patients (85%) reached PASS for the KOOS ADL. There was no significant difference in the percentage of patients who reached PASS for all KOOS subscales and Lysholm between the two groups. Conclusion PASS was achieved in 85% of all UKAs for KOOS ADL, similar to reports for TKA. Fixed-bearing, medial, non-robotically-assisted UKA resulted in 97% survival at ten years in both the ACL-deficient and ACL-intact groups. There was no significant difference in all outcomes between the two groups. Understanding PASS will allow better communication between surgeons and patients to improve the surgical management of patients with single compartment OA of the knee. This study provides mid- to long-term data supporting the use of PASS to document outcomes following UKA. PASS was met in more than 85% of patients with no differences between ACL-deficient and ACL-intact knees at a mean follow-up of nine years. Cite this article: Bone Joint J 2021;103-B(8):1367–1372.

scholarly journals Complications, Reasons for Reoperation, and 5-Year Prosthesis Survival Compared Between the Cemented and Cementless Oxford Unicompartmental Knee Arthroplasty Fixation Techniques at Thailand’s Largest National Tertiary Referral Center

2021 ◽  
Author(s):  
Jirayu Paugchawee ◽  
Chaturong Pornrattanamaneewong ◽  
Pakpoom Ruangsomboon ◽  
Rapeepat Narkbunnam ◽  
Keerati Chareancholvanich
Keyword(s):  
Knee Osteoarthritis ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Cox Proportional Hazards Model ◽  
Implant Survival ◽  
Unicompartmental Knee ◽  
Prosthesis Survival ◽  
Significant Difference ◽  
Oxford Unicompartmental Knee Arthroplasty

Abstract Background: Oxford unicompartmental knee arthroplasty (OUKA) yields favorable outcomes in patients with medial compartmental knee osteoarthritis; however, it remains unknown whether cemented or cementless OUKA fixation delivers better outcomes in Asian population. Accordingly, this study aimed to investigate the complications, reasons for reoperation, and 5-year prosthesis survival compared between cemented and cementless OUKA in Thai patients.Methods: A total of 466 cemented and 36 cementless OUKA that were performed during 2011-2015 with a minimum follow-up of five years were included. With reoperation for any reason as the endpoint, Kaplan-Meier analysis was performed to compare 5-year implant survival between groups. Complications, reasons for reoperation, and 90-day morbidity and mortality were compared between groups. Cox proportional hazards model was used to identify independent predictors of implant survival.Results: There was no significant difference in 5-year implant survival between the cemented and cementless groups (96.4% vs. 94.4%, p=0.375). The mean implant survival time was 113.0±0.8 and 70.8±1.9 months in the cemented and cementless groups, respectively (p=0.383). The most common reason for reoperation was bearing dislocation, and only one patient had 90-day morbidity. There was no significant difference between groups for complications or reasons for reoperation. No independent predictors of implant survival were identified in multivariate analysis.Conclusions: OUKA was shown to be a safe and durable reconstructive procedure in Thai patients with medial compartmental knee osteoarthritis. There was no significant difference in implant survival between the cemented and cementless groups during the 5-year follow-up, and no independent predictors of implant survival were identified. Trial registration: Thai Clinical Trials Registry, TCTR20200427004. Registered 27 April 2020 – Retrospectively registered.

scholarly journals Reduction in tibiofemoral conformity in lateral unicompartmental knee arthroplasty is more representative of normal knee kinematics

2019 ◽  
Vol 8 (12) ◽  
pp. 593-600 ◽  
Author(s):  
Yong-Gon Koh ◽  
Jin-Ah Lee ◽  
Hwa-Yong Lee ◽  
Hyo-Jeong Kim ◽  
Hyun-Seok Chung ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Femoral Component ◽  
Knee Arthroplasty ◽  
Unicompartmental Knee Arthroplasty ◽  
Tibial Plateau ◽  
Knee Kinematics ◽  
Lateral Tibial Plateau ◽  
Unicompartmental Knee ◽  
Tibial Insert ◽  
Femoral Rollback

Aims Commonly performed unicompartmental knee arthroplasty (UKA) is not designed for the lateral compartment. Additionally, the anatomical medial and lateral tibial plateaus have asymmetrical geometries, with a slightly dished medial plateau and a convex lateral plateau. Therefore, this study aims to investigate the native knee kinematics with respect to the tibial insert design corresponding to the lateral femoral component. Methods Subject-specific finite element models were developed with tibiofemoral (TF) and patellofemoral joints for one female and four male subjects. Three different TF conformity designs were applied. Flat, convex, and conforming tibial insert designs were applied to the identical femoral component. A deep knee bend was considered as the loading condition, and the kinematic preservation in the native knee was investigated. Results The convex design, the femoral rollback, and internal rotation were similar to those of the native knee. However, the conforming design showed a significantly decreased femoral rollback and internal rotation compared with that of the native knee (p < 0.05). The flat design showed a significant difference in the femoral rollback; however, there was no difference in the tibial internal rotation compared with that of the native knee. Conclusion The geometry of the surface of the lateral tibial plateau determined the ability to restore the rotational kinematics of the native knee. Surgeons and implant designers should consider the geometry of the anatomical lateral tibial plateau as an important factor in the restoration of native knee kinematics after lateral UKA. Cite this article: Bone Joint Res 2019;8:593–600.

scholarly journals Fracture of the Femoral Component Caused by Insufficient Crimping after Modern Unicompartmental Knee Arthroplasty

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Yoichi Ishibashi ◽  
Tasuku Mashiba ◽  
Masaki Mori ◽  
Tetsuji Yamamoto
Keyword(s):  
Femoral Component ◽  
Knee Arthroplasty ◽  
Revision Surgery ◽  
Unicompartmental Knee Arthroplasty ◽  
Radiolucent Line ◽  
Cement Mantle ◽  
Metallic Component ◽  
Postoperative Course ◽  
Unicompartmental Knee ◽  
First Case

Fracture of a femoral component after modern unicompartmental knee arthroplasty is very rare. Although this is not the first case on this subject, no study has reported insufficient crimping as the cause of femoral component loosening that led to breakage of a metallic component. A 69-year-old man underwent medial unicompartmental knee arthroplasty for right medial knee osteoarthritis. His early postoperative course was good; however, the 1-year postoperative radiograph showed an apparent radiolucent line around the femoral component, and he occasionally had right knee pain. However, he had been followed up conservatively because he had been doing well even while doing heavy agricultural work. At 8 years after surgery, because breakage of the femoral component was found, revision surgery was performed using bicruciate-retaining total knee arthroplasty. The removed fractured femoral component revealed a thick cement mantle detached from the bone surface. The postoperative course of the patient after the revision surgery was excellent. We suggest that the causes of femoral component breakage include early implant loosening caused by uneven cement crimping of the femoral component to the bone and excessive loading stress as a result of heavy labour.

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