Tokifumi Majima

Intraoperative medial pivot affects deep knee flexion angle and patient-reported outcomes after total knee arthroplasty.

The aim of this study was to evaluate the relationship between clinical results including patient-reported outcomes and intraoperative knee kinematic patterns after total knee arthroplasty (TKA). A cross-sectional survey of forty consecutive medial osteoarthritis patients who had a primary TKA using a CT-based navigation system was conducted. Subjects were divided into two groups based on intraoperative kinematic patterns: a medial pivot group (n = 20) and a non-medial pivot group (n = 20). Subjective outcomes with the new Knee Society Score and clinical outcomes were evaluated. The functional activities, patient satisfaction and the knee flexion angle of the medial pivot group were significantly better than those of the non-medial pivot group. An intraoperative medial pivot pattern positively influences deep knee flexion and patient-reported outcomes.

Correlation Between Knee Kinematics and Patellofemoral Contact Pressure in Total Knee Arthroplasty

The aim of this study is to evaluate the relationship between patellofemoral contact stress and intraoperative knee kinematic patterns after mobile bearing total knee arthroplasty (TKA). Medial osteoarthritic knees of forty-six posterior-stabilized total knee prostheses were evaluated using a computed tomography-guided navigation system. Subjects were divided into two groups based on intraoperative knee kinematic patterns: the medial pivot group (n=19) and the non-medial pivot group (n=27). Mean intraoperative patello-femoral contact stress was significantly lower in the medial pivot group than in the non-medial pivot group (1.7MPa vs. 3.2MPa, P<0.05). An intraoperative medial pivot pattern results in reduced patello-femoral contact stress.

External rotation of the femoral component decreases patellofemoral contact stress in total knee arthroplasty

PurposeThe purpose of this study was to investigate the relationship between patellofemoral (PF) contact stress in vivo and the alignment of the femoral component in patients after total knee arthroplasty (TKA).MethodsThirty knees with medial compartment osteoarthritis that underwent mobile-bearing TKA with modified gap technique were evaluated. Surgery was performed using a subvastus approach to eliminate the effect of the approach to muscle balance, with a computed tomography-based navigation system (Vector Vision 1.61; Brain Lab, Heimstetten, Germany). PF contact stress was measured by a Flexiforce pressure sensor (Nitta Co., Ltd., Osaka, Japan) intraoperatively, and the results were compared with the alignment of the femoral component after TKA.ResultsThe PF contact stress was not correlated with sagittal and coronal alignment of the femoral component and patellar tracking, whereas rotational alignment of the femoral component was negatively correlated with PF contact stress (rxa0=xa0−0.718, pxa0<xa00.01).ConclusionsRegarding the alignment of the femoral component, only the rotational alignment of the femoral component was correlated with PF contact stress. PF contact stress decreased more as the femoral component rotated more externally.Level of evidenceCase control study, Level III.

Medial meniscal posterior root/horn radial tears correlate with cartilage degeneration detected by T1ρ relaxation mapping.

OBJECTIVEnThis study aimed to identify factors on routine pulse sequence MRI associated with cartilage degeneration observed on T1ρ relaxation mapping.nnnMATERIALS AND METHODSnThis study included 137 subjects with knee pain. T1ρ values were measured in the regions of interest on the surface layer of the cartilage on mid-coronal images of the femorotibial joint. Assessment of cartilage, subchondral bone, meniscus and ligaments was performed using routine pulse sequence MRI. Radiographic evaluation for osteoarthritis was also performed.nnnRESULTSnMultiple regression analysis revealed posterior root/horn tears to be independent factors increasing the T1ρ values of the cartilage in the medial compartment of the femorotibial joint. Even when adjusted for radiographically defined early-stage osteoarthritis, medial posterior meniscal radial tears significantly increased the T1ρ values.nnnCONCLUSIONSnThis study showed that posterior root/horn radial tears in the medial meniscus are particularly important MRI findings associated with cartilage degeneration observed on T1ρ relaxation mapping. Morphological factors of the medial meniscus on MRI provide findings useful for screening early-stage osteoarthritis.

Split Fracture of the Posteromedial Tubercle of the Talus: Case Report and Proposed Classification System

We describe a rare case of a fracture of the medial tubercle of the posterior process of the talus in a 16-year-old male athlete who fell during basketball practice. The patient presented to our orthopedic clinic when pain and swelling had persisted despite 2 weeks of anti-inflammatory medication and rest. Computed tomography and magnetic resonance imaging scans revealed a fracture of the posteromedial tubercle of the talus and a small amount of retained fluid in the joint. Immobilization with a below-the-knee cast and non-weightbearing for 4 weeks, with a gradual return to full activity, was successful. At the 1-year follow-up evaluation, the patient expressed no complaints. Fracture of the posteromedial tubercle of the talus will usually result in a misdiagnosis or delayed diagnosis owing to the insidious onset of symptoms. We believe the present fracture configuration resulted from the vertical compression force that occurred on landing by posterior medial ankle impingement in plantarflexion-supination, modifying the conventional concept of the posteromedial tubercle fracture. We also present a suggested classification with a flowchart diagram.

A pilot study comparing the efficacy of radiofrequency and microwave diathermy in combination with intra-articular injection of hyaluronic acid in knee osteoarthritis

[Purpose] This study aimed to compare the efficacy of radiofrequency diathermy with that of microwave diathermy in combination with intra-articular injection of hyaluronic acid into the knee of patients with osteoarthritis (OA). [Subjects] A total of 17 patients with knee OA were enrolled. The participants were randomly divided into two groups: a radiofrequency diathermy group (RF group, 9 subjects), and a microwave diathermy group (MW group, 8 subjects). [Methods] Subjects received radiofrequency or microwave thermal therapy 3 times at 1-week intervals. Intra-articular injection of hyaluronic acid was administered 10u2005min before every thermal therapy session. The outcome was evaluated using the Japan Orthopaedic Association (JOA) and the Lequesne Index (LI) at baseline, at weeks 1 (1 week after the first thermal therapy) and 3 (1 week after the last thermal therapy). [Results] The JOA scale increased significantly after three sessions of thermal therapy in the RF group, while no significant increase was observed in the MW group. LI decreased significantly after 3 weeks in the RF group. In the MW group, there was no significant difference in LI between the two time points. [Conclusion] This study revealed that symptom relief in patients with knee OA was greater with radiofrequency diathermy than with microwave diathermy with concurrent use of hyaluronic acid injection, presumably due to the different heating characteristics of the two methods.

AB0858 MRI Analysis of Knee Joints by T1Rho Mapping in Young and Middle-Aged Cases Without Radiological Osteoarthritis

Background Recently, some studies have reported that medial meniscal posterior horn tears often occur in aged people, and suggested that these tears could be related to the development of knee osteoarthritis (OA). However, limited data concerning this pathogenesis in young and middle-aged cases without radiological OA changes have been reported. T1rho (or T1 relaxation time in rotating frame)-weighted MRI has recently been proposed as a promising alternative biomarker to existing conventional morphological MRI. T1rho values are believed to reflect the condition of the extracellular matrix of articular cartilage, and particularly the proteoglycan concentration. Objectives The purpose of this study was to analyze the interaction between cartilage degradation depicted by T1rho mapping and meniscus injuries in the knees of cases under 50 years old without obvious radiological OA features. Methods This study included 87 subjects under 50 years old with knee pain (mean: 38.3 years old). We added another 10 healthy volunteers to be used as healthy controls (mean: 38.7 years old). Standard standing anteroposterior radiographs of the knee were obtained in all subjects. The Kellgren-Lawrence (KL) grade was determined by three experienced orthopaedic surgeons. MR examinations were performed using a 3.0T MR unit. 3D T1rho-weighted fast field echo imagingwas performed for T1rho quantification. After direct segmentation by referring to the proton density weighted (PDW) images, 12 regions of interest (ROIs) were manually drawn on the T1rho map of a single coronal image slice which showed a mid-body segment of the medial meniscus. Morphological MRI assessment of ligaments, menisci and subchondral bone was performed by sagittal/coronal fat-suppressed T2-weighted imaging and sagittal PDW imaging. Meniscal lesions were graded using a modified Whole Organ Magnetic Resonance Imaging Score (WORMS) of the knee. Results The study revealed that KL grade, the medial meniscus WORMS and the presence/absence of posterior root/horn radial tears in medial meniscus influenced the T1rho values in the medial femorotibial joint. A multivariate analysis corrected for age and the KL grade revealed that abnormal findings in the posterior segment of the medial meniscus independently increased the T1rho values in the ROIs of the medial compartment (P<0.01). Conclusions Our results demonstrated that morphological factors of the meniscus on normal MR images are useful for estimating the T1rho values in the cartilage. WORMS provides findings that are useful for screening for early-stage OA and pre-OA in routine medical care. Posterior root/horn radial tears in the medial meniscus depicted on routine MRI are particularly important findings associated with cartilage degeneration observed on T1rho relaxation mapping, even in patients under 50 years old without obvious radiological OA. In other words, abnormalities in the posterior segment of the medial meniscus on MR images indicate that degeneration of the medial femorotibial joint is already in progress, even in young patients, and even when plain radiographs show no abnormalities. Therefore, a programme for preventing future OA is needed for these patients. Disclosure of Interest None declared