Three-year clinical and radiological results of a cruciate-retaining type of the knee prosthesis with anatomical geometry developed in Japan

A Comparative Study of Clinical Outcomes Between Cruciate-Retaining and Posterior-Stabilized Total Knee Arthroplasty: A Propensity Score-Matched Cohort Study

INTRODUCTION

We investigated a comparison of clinical outcomes between cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty. However, it is still controversial which design leads to better clinical results. In clinical settings, choosing either CR or PS is likely based on the surgeon's preferences. In this study, short-term clinical outcomes between CR and PS in patients who received a single knee prosthesis were compared using propensity score matching.

METHODS

Two hundred and twelve CR and 43 PS of a single knee prosthesis were enrolled in this study. After propensity score matching, 34 knees each in the CR and PS groups were chosen and were without significant differences in age at operation, gender, BMI, preoperative range of motion (ROM), preoperative femorotibial angle (FTA), and presence or absence of patellar replacement. Clinical scores, including ROM, Knee Society score (KSS), knee injury and osteoarthritis outcome score (KOOS), except for the sports subscale, were compared between the CR and PS groups preoperatively and two years postoperatively.

RESULTS

Postoperatively, there were no significant differences in FTA, ROM, or KSS. Preoperative scores for the KOOS except for the pain subscale were comparable between the groups. Postoperatively, however, the PS group had a significantly higher score in the ADL subscale compared to the CR group (PS: 89.5 vs. CR: 80.8, p = 0.017). The KOOS subscales other than activities of daily living (ADL) were comparable between the groups.

CONCLUSIONS

In this propensity score-matched cohort study, PS showed a better outcome for the ADL than the CR design. These findings suggest that choosing either CR or PS should not depend on the surgeon's preferences. A PS design may be preferable to CR for elderly patients.

Difference in implant design affects midflexion rotational laxity in cruciate-retaining total knee arthroplasty: a computer navigation study

PURPOSE

This study aimed to compare midflexion rotational laxity between two different design concept models of cruciate-retaining total knee arthroplasty: symmetrical surface design of neutral joint line obliquity and asymmetrical surface design of varus joint line obliquity.

METHODS

Sixty-three knees that underwent cruciate-retaining total knee arthroplasty were evaluated. Manual maximum passive rotational stress without acceleration was applied to the knees under navigation monitoring. Pre-operative and post-operative internal and external rotational angles were measured at 30°, 45°, 60°, and 90° knee flexion.

RESULTS

The post-operative internal rotational laxity was significantly increased compared with pre-operative levels at 30°, 45°, 60°, and 90° flexion among all subjects (mean 9.7° vs 11.1°, 10.6° vs 11.6°, 11.2° vs 12.9°, and 13.2° vs 14.9°; p = 0.01, 0.04, 0.001, and 0.008, respectively). The post-operative external rotational laxity was significantly decreased compared to pre-operative levels at 30°, 45°, 60°, and 90° flexion among all subjects (mean 10.8° vs 6.8°, 12.5° vs 9.4°, 12.8° vs 10.0°, and 11.3° vs 9.5°; p < 0.0001, < 0.0001, < 0.0001, and 0.0008, respectively). The post-operative total rotational laxity significantly decreased, compared with pre-operative levels, at 30° and 45° flexion among all subjects (mean 20.4° vs 17.9°, and 23.1° vs 21.1°; p = 0.002 and 0.04, respectively). The post-operative total rotational laxity was significantly smaller in asymmetrically designed total knee arthroplasty than in symmetrically designed total knee arthroplasty at 30°, 45°, and 60° flexion (mean 19.3° vs 15.8°, 22.8° vs 18.7°, and 24.4° vs 20.8°; p = 0.03, 0.03, and 0.02, respectively), whereas no significant difference was observed at 90° flexion.

CONCLUSION

Compared to symmetrical surface design, asymmetrical surface design resulted in lower rotational laxity at the midflexion range in cruciate-retaining total knee arthroplasty.

LEVEL OF EVIDENCE

III.

The impact of postoperative inclination of the joint line on clinical outcomes in total knee arthroplasty using a prosthesis with anatomical geometry

The goal of this study was to investigate the impact of postoperative inclination of the joint line on clinical results after total knee arthroplasty (TKA) using a prosthesis with anatomical geometry. This study included 145 primary cruciate-retaining type of knee prosthesis with anatomical geometry. Three years postoperatively, clinical outcomes including the patient-reported outcomes (PROs) were recorded. Limb alignment was evaluated by the hip-knee-ankle (HKA) axis and inclination of the joint line was assessed by the joint line orientation angle (JLOA). Knees were divided into two groups according to the HKA: in-range (- 3 to 3°) and outlier group (< - 3° or > 3°) or the JLOA: in-range (2-4°) and outlier group (< 2° or > 4°), and clinical outcomes were compared between the groups. Postoperative Knee Society Function Score (KS-FS) was significantly higher in the HKA in-range group than the outlier group (p = 0.01). The Knee Society Knee Score and all subscales of the Knee injury Osteoarthritis Outcome Score were comparable between the groups. A multivariate analysis revealed a significant association between age at operation and postoperative KS-FS > of 80 points. Neither HKA in-range nor JLOA in-range were associated with the higher knee function. In conclusion, TKA-postoperative inclination of the joint line was not relevant to the short-term PROs. Treatment strategies that attempt to make joint line inclination in order to improve postoperative PROs should be avoided, and alignment goals such as kinematic alignment should be considered carefully.

Lateral shift of the femoral condyle after total knee arthroplasty: simulation using 2D-templates of the medial pivot design on knee radiographs of young Japanese patients

Background

Total knee arthroplasty (TKA) is an established surgical treatment for advanced knee osteoarthritis by which patients can expect improvement of knee pain and function. Although many surgeons have investigated limb alignment after TKA, changes in coronal positional relation between the femur and tibia are not known well.

Methods

Radiographs of 105 knees of young Japanese patients between 20 and 49 years-old (60 men and 45 women) without osteoarthritic changes who received arthroscopic surgeries at our hospital were used in this study. Using 2D-templates of the medial pivot design (the FINE total knee), we simulated TKA on a SYNAPSE-PACS software. First, the femoral component was placed in normal knee alignment and then was merged to the medial concave of the insert where the tibial component was placed in neutral alignment. The length of the mediolateral shift of the femoral component was measured as an estimate of lateral shift of the femoral condyle, of which association with radiographic parameters including the femorotibial angle (FTA), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA) was analyzed. Subjects were classified into three groups according to the femoral component size that was chosen in simulation of TKA, and the lateral shift of the femoral condyle was compared between groups.

Results

The estimated mean lateral shift of the femoral condyle was 5.99 ± 1.98 mm and was greater in males than females (p < 0.05). Also, it was most highly correlated with the medial proximal tibial angle (MPTA) (r = − 0.553, p < 0.01). A group receiving larger component sizes significantly shifted more laterally compared with a group receiving smaller component sizes (p < 0.01).

Conclusions

These results suggest that the coronal positional relation between the femur and tibia is altered and subsequent ligament imbalance may occur after mechanically aligned TKA using the medial pivot design.

Safety and Efficacy of Single Condylar Knee Prosthesis When Treating Knee Single Compartment Osteoarthritis: A Prospective, Case-Randomized Controlled Study

Objective. The aim of this study is to explore the safety and efficacy of single condylar knee prosthesis when treating knee single compartment osteoarthritis by measuring the decrease of hemoglobin, total postoperative blood loss, maximum reduction of HCT, and knee joint activity. Methods. A total of 80 patients with knee joint single compartment osteoarthritis treated in our hospital from January 2020 to December 2021 were studied. They were randomly assigned to a study group (n = 40) and a control group (n = 40). The study group was treated with total knee prosthesis, while the control group was treated with simple knee prosthesis. The decrease rate of hemoglobin, the amount of bleeding, and the maximum decrease of hematocrit were compared after treatment. The range of motion of knee joint was evaluated by the Fugl-Meyer motor function scale (FM-B) and Berg balance scale (BBS). Results. The decrease of hemoglobin in the study group at 24 hours, 36 hours, and 48 hours after treatment was remarkably lower ( $P$  < 0.05). The total blood loss and the maximum reduction of hematocrit(HCT) in the study group were lower ( $P$  < 0.05). The range of motion (ROM) of the knee joint in the study group at 6 and 12 months after treatment was remarkably higher than that before treatment and remarkably higher compared to the control group ( $P$  < 0.05). The FM-B scale and BBS scale of the studied cohort at 6 and 12 months after treatment were remarkably higher than those before treatment and were remarkably higher compared to the control’s ( $P$  < 0.05). Conclusion. The unicondylar knee prosthesis is safer and more effective in the treatment of noncompartmental osteoarthritis of the knee, facilitating less trauma and perioperative blood loss and enhancing the patient’s motion and balance.

Traditional Chinese-Hong Kong version of Forgotten Joint Score-12 (FJS-12) for patients with osteoarthritis of the knee underwent joint replacement surgery: cross-cultural and sub-cultural adaptation, and validation

Background

A patient-reported outcome (PRO) tool which reflects the outcomes of patients underwent total knee arthroplasty (TKA) are important to be “ceiling effect free” which commonly used PRO tools face. Forgotten joint score-12 (FJS-12) has been proved to reduce or even free from ceiling effect. FJS-12 has been translated to different languages. The objectives of this study are to validate FJS-12 in Traditional Chinese-Hong Kong language and look for the goodness of FJS-12 still exist in this language adapted FJS-12 version.

Methods

FJS-12 was administered to 75 patients whose majority was obese underwent TKA between September 2019 and March 2020. Patients completed 3 sets of questionnaires (FJS-12, Oxford Knee Score (OKS), and Numeric Rating Scale (NRS)) twice, 2 weeks apart. Reliability, internal consistency, responsiveness, test–retest agreement and discriminant validity were evaluated.

Results

Reliability of FJS-12 showed moderate to excellent internal consistency (Cronbach’s α = 0.870). Test–retest reliability of FJS-12 was good (ICC = 0.769). Bland–Altman plot showed good test–retest agreement. Construct validity in terms of correlations between FJS-12 and OKS, and FJS-12 and NRS were moderate at baseline (Pearson’s coefficient r = 0.598) and good at follow-up (r = 0.879). Smallest detectable change (Responsiveness) was higher than MIC. Floor effect was none observed, and ceiling effect was low. Discriminant validity was found to have no significance. BMI (obesity) did not affect FJS-12 outcomes.

Conclusions

The Traditional Chinese-Hong Kong version of FJS-12 showed good test–retest reliability, validity, responsiveness, BMI non-specific, with no floor and low ceiling effects for patients who underwent TKA. Sub-culture differences in individual PRO tools should be considered in certain ethnicities and languages.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05156-5.