Functional knee phenotypes: A helpful classification tool for visualizing potential femoral varus in restricted kinematic alignment total knee arthroplasty in Japan.

Purpose: Restricted kinematic alignment (rKA) is a modified technique of kinematically aligned total knee arthroplasty (TKA) within a safe alignment range for long-term implant survivorship. The purpose of this study was to clarify (1) the distribution of functional knee phenotypes in patients who underwent TKA in Japan and (2) whether the application of this classification results in anatomically neutral alignment after rKA TKA.

Methods: Overall, 114 TKA surgeries (mechanical alignment [MA]: 49; rKA: 65) were performed.

Effects of Unrestricted Kinematically Aligned Total Knee Arthroplasty with a Modified Soft-Tissue Respecting Technique on the Deformity of Limb Alignment in Japanese Patients.

: Unrestricted kinematic alignment total knee arthroplasty (KA-TKA) with a soft-tissue respecting technique (STRT) is a soft-tissue-dependent tibial resection entailing the restoration of the original soft-tissue tension using ligamentotaxis after resurfacing the femur, based on the concept of restoring the native or pre-osteoarthritis alignment in each patient. However, there is no consensus on the indications of unrestricted KA-TKA with the STRT. We modified the STRT, followed by an investigation of the effects of surgery on the postoperative hip-knee-ankle angle (HKAA).

Closed-leg standing long leg radiographs can be a useful tool to assess whether the joint line is parallel to the ground in restricted kinematic alignment total knee arthroplasty.

Purpose: Restricted kinematic alignment (rKA) is a modified technique of kinematic alignment (KA) total knee arthroplasty (TKA) for patients with an outlier or atypical knee anatomy, striving to preserve the native knee joint line parallel to the ground in a bipedal stance. This study aimed to evaluate the accuracy of rKA TKA with a computed tomography (CT)-based patient-specific instrument (PSI) to achieve the preoperative plan with the joint line parallel to the ground level.

Methods: Using a CT-based PSI, 74 closed-leg standing long-leg radiographs were obtained before and after rKA TKA.

Agreement and accuracy of radiographic assessment using a decision aid for medial Oxford partial knee replacement: multicentre study.

Background: Indication for mobile-bearing partial knee replacement (PKR) is made on the basis of a radiological decision aid. This study aimed to reveal the inter-rater reproducibility and accuracy of the decision aid when used by experienced surgeons.

Patients And Methods: Anonymised radiographic image sets (anteroposterior, lateral, varus/valgus stress in 20° knee flexion, and skyline views) from 20 consecutive patients who underwent knee replacement were assessed by 12 experienced surgeons.

Tibial shape and size predicts the risk of tibial plateau fracture after cementless unicompartmental knee arthroplasty in Japanese patients.

Aims: Cementless unicompartmental knee arthroplasty (UKA) has advantages over cemented UKA, including improved fixation, but has a higher risk of tibial plateau fracture, particularly in Japanese patients. The aim of this multicentre study was to determine when cementless tibial components could safely be used in Japanese patients based on the size and shape of the tibia.

Methods: The study involved 212 cementless Oxford UKAs which were undertaken in 174 patients in six hospitals.

Mucoid degeneration of the cruciate ligaments in osteoarthritis under primary total knee arthroplasty.

Mucoid degeneration of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) with osteoarthritis is rarely reported. We experienced two knee osteoarthritic patients who had symptomatic mucoid degeneration of their ACL, and their PCL was also diagnosed as mucoid degeneration in histological evaluation. Preoperative radiological evaluation could not reveal precisely whether the degeneration had extended to the PCL.

Comparison of an Accelerometer-Based Portable Navigation System, Patient-Specific Instrumentation, and Conventional Instrumentation for Femoral Alignment in Total Knee Arthroplasty.

Purpose: The KneeAlign2 (KA2, OrthoAlign Inc.) accelerometer-based portable navigation system and patient-specific instrumentation (PSI; Signature, ZimmerBiomet) are widely used for ideal femoral component alignment in total knee arthroplasty (TKA). However, there has been no comparative study of the KA2 system, PSI, and conventional intramedullary instrumentation (CON).

Arthroscopic Scar Resection for the Treatment of Anteromedial Knee Pain after Oxford Unicompartmental Knee Arthroplasty: A Case Report.

Introduction: It has been reported that the unicompartmental knee arthroplasty has good long-term outcomes for Western and Japanese patients. Alternatively, several reports have described reoperations after unicompartmental knee arthroplasty because of post-operative knee pain and sometimes it is difficult to diagnose the cause of pain.

Case Report: We treated a patient with anteromedial knee pain caused by intra-articular scar tissue that contained residual cement fragments on the anterior surface of a femoral implant following Oxford unicompartmental knee arthroplasty.