Evaluation of complete and incomplete subscapularis tendon tear on preoperative magnetic resonance imaging.

Background: This study aims to evaluate the significance of preoperative magnetic resonance imaging findings to predict subscapularis tear confirmed at arthroscopic surgery.

Methods: Sixty-four consecutive shoulders that underwent preoperative magnetic resonance imaging examination and arthroscopic shoulder operations were retrospectively reviewed. Under arthroscopic examination, complete subscapularis tear was defined as a full-thickness tear and incomplete subscapularis tear as tendon detachment larger than 5 mm from the insertion on the joint side.

Is it possible to predict the final component gap in flexion before femoral posterior condylar osteotomy in cruciate-retaining and posterior-stabilized total knee arthroplasty?

Background: In total knee arthroplasty (TKA) with posterior condylar osteotomy using anatomical landmarks, predicting the final flexion gap is impossible, as it differs with the presence or absence of the posterior cruciate ligament. We compared the predicted flexion gap, based on pre-femoral posterior condylar osteotomy measurements, with the postsurgical final flexion gap in cruciate-retaining (CR) and posterior-stabilized (PS) TKA.

Methods: One hundred knees of patients with osteoarthritis were included: 35 underwent CR, and 65 PS TKA.

A Human Amnion-Derived Extracellular Matrix-Coated Cell-Free Scaffold for Cartilage Repair: In Vitro and In Vivo Studies.

Objective: Extracellular matrix (ECM) derived from human amniotic mesenchymal cells (HAMs) has various biological activities. In this study, we developed a novel HAM-derived ECM-coated polylactic-co-glycolic acid (ECM-PLGA) scaffold, examined its property on mesenchymal cells, and investigated its potential as a cell-free scaffold for cartilage repair.

Materials And Methods: ECM-PLGA scaffolds were developed by inoculating HAM on a PLGA.

Successful treatment of methicillin-resistant Staphylococcus aureus osteomyelitis with combination therapy using linezolid and rifampicin under therapeutic drug monitoring.

Linezolid is an effective antibiotic against most gram-positive bacteria including drug-resistant strains such as methicillin-resistant Staphylococcus aureus. Although linezolid therapy is known to result in thrombocytopenia, dosage adjustment or therapeutic drug monitoring of linezolid is not generally necessary. In this report, however, we describe the case of a 79-year-old woman with recurrent methicillin-resistant S.

Intraoperative measurements of femoral anterior tangent (FAT) line for determining the rotational alignment of femoral component of total knee arthroplasty.

Previously, we reported using CT images that the anterior surface of the femur immediately proximal to the trochlea and its tangent line (femoral anterior tangent line; FAT line) could be used as a good index of the femoral rotation. In this study, we developed a jig that allowed us to measure the FAT line during surgery, and we examine the relation between preoperative and intraoperative measurement values. The results indicated that the average intraoperative measurement value of the 'surgical' FAT line was 9.

Effects of kneeling on tibiofemoral contact pressure and area in posterior cruciate-retaining and posterior cruciate-sacrificing total knee arthroplasty.

The objective of this study was to measure the effect of kneeling on tibiofemoral contact following cruciate-retaining and posterior-stabilized total knee arthroplasty. Five cadaveric knees were tested on a custom testing system that allowed physiologic muscle loading. Three forces were used to simulate nonkneeling, double-stance kneeling, and single-stance kneeling at flexion angles of 90°, 105°, 120°, and 135°.

Effects on tibiofemoral biomechanics from kneeling.

Background: Repetitive kneeling in certain occupations, hobbies and cultures is associated with tibiofemoral joint osteoarthritis. The biomechanics of kneeling is therefore of interest. This cadaveric study investigated tibiofemoral joint contact areas, pressures, and kinematics in response to kneeling.

Femoral anterior tangent line of the osteoarthritic knee for determining rotational alignment of the femoral component in total knee arthroplasty.

Several reference axes have been used to establish femoral rotational alignment during total knee arthroplasty. The current study examined the configuration of the anterior surface of the femur immediately proximal to the trochlea as an alternative rotational landmark. An analysis of computed tomographic images of 150 knees with osteoarthritis indicated that the configuration of the surface is mostly flat or slightly depressed, and the line tangential to the surface (femoral anterior tangent line; FAT line) was consistently determined to be 12.

Biomechanical effects of patellar positioning on intraoperative knee joint gap measurement in total knee arthroplasty.

Background: Balancing both the lateral/medial and extension/flexion joint gaps is a prerequisite for soft tissue balance in total knee arthroplasty. The purpose of this study was to quantify the effects of patellar positioning and quadriceps load during total knee arthroplasty on knee joint gap measurements.

Methods: Eight fresh-frozen cadaveric knees ranging in age from 65 to 85 years old were used.

Activities of daily living after total hip arthroplasty. Is a 32-mm femoral head superior to a 26-mm head for improving daily activities?

Range of motion (ROM) of the hip joint after total hip arthroplasty (THA) could be increased by using a larger prosthetic femoral head, but it is not known whether the activities of daily living (ADL) are influenced by THA with different head sizes. Our objective was to compare postoperative ADL in patients who underwent THA using a head diameter of 26 mm or 32 mm. We assessed the range of motion and the mode of ADL after cementless primary THA.

Intraoperative patellar tendon strain: predicting the range of knee flexion after total knee arthroplasty.

Background: The preoperative range of motion is an important factor that influences the range of motion after total knee arthroplasty. Because the length and tightness of the extensor mechanism are extracapsular elements with an influence on knee flexion, it is reasonable to assume that the tension of the knee extensor mechanism during surgery has a considerable impact on the postoperative range of motion. The purpose of this study was to determine the influence of the tightness of knee extensor mechanism on postoperative knee flexion.

Joint gap changes with patellar tendon strain and patellar position during TKA.

Unlabelled: Balancing of the joint gap in extension and flexion is a prerequisite for success of a total knee arthroplasty. The joint gap is influenced by patellar position. We therefore hypothesized the state of the knee extensor mechanism (including the patellar tendon) would influence the joint gap.

Severe bone defects and reduced mineralization caused by massive metallosis after total knee arthroplasty: histopathologic and bone morphometric findings.

We encountered a patient who developed metallosis after total knee arthroplasty (TKA), resulting in loosening of the implant, bone resorption, reduced bone formation, and fracture. The implant was replaced with a NexGen modular revision TKA system after autologous bone and hydroxyapatite granule grafting. Histopathologic examination showed accumulation of metallic debris and tartrate-resistant acid phosphatase-positive cells around the trabecular and cortical bone.

Efficient gene delivery to articular cartilage using electroporation.

Abstract Effective in vivo gene transfer into articular cartilage has not yet been established. Since chondrocytes are embedded within a rich extracellular matrix, various gene transfer methods have failed to introduce genes into deeper layers of the articular cartilage. In this study, we developed new superfine pointed needle electrodes for in situ electroporation (EP), and investigated the efficiency of gene transfer into articular cartilage with different degrees of degeneration.

Quantitative analysis of the effect of lumbar orthosis on trunk muscle strength and muscle activity in normal subjects.

We studied the effect of lumbar orthosis on trunk muscle strength and muscle activity during flexion-extension bending of the trunk in 31 male volunteers. Trunk muscle strength was measured with a kinetic measurement system. Peak torque was calculated by using the mean torque of five repetitions.

Fixation of the NexGen HA-TCP-coated cementless, screwless total knee arthroplasty: comparison with conventional cementless total knee arthroplasty of the same type.

We performed a 12-month prospective study on 59 patients (92 knees) who underwent NexGen (Zimmer Inc, Warsaw, IN) cruciate-retaining total knee arthroplasty. In the control group, uncoated components were fixed using screws, whereas the hydroxyapatite-tricalcium phosphate (HA-TCP) group underwent screwless fixation of coated components. At 12 months postoperatively, there was a radiographic clear zone around the femoral and tibial components of 56.