Objectives

The purpose of this study was to clarify the appearance of the reparative tissue on the articular surface and to analyse the properties of the reparative tissue after hemicallotasis osteotomy (HCO) using MRI T1ρ and T2 mapping.

Introduction

Highly cross-linked polyethylene (HXLPE) was developed to reduce the wear of articular-bearing surfaces in total hip arthroplasty (THA). This study aimed to compare the mean linear wear of HXLPE with a 22.225 mm diameter zirconia head with that of conventional polyethylene (CPE) with a 22.225 mm diameter ortron head.

Introduction

Antibiotic-loaded acrylic cement (ALAC) is employed in the treatment or prevention of infected total hip arthroplasty (THA). We have administered vancomycin (VCM) as the ALAC for the treatment of THAs with methicillin-resistant Staphylococcus aureus, or for the prevention of THAs with high risks. This study aimed to evaluate the serum concentration of VCM from ALAC in THA or cement beads.

We report the long-term outcome of 33 patients (37 knees) who underwent proximal tibial open-wedge osteotomy with hemicallotasis (HCO) for medial osteoarthritis of the knee between 1995 and 2000. Among these, 29 patients with unilateral HCO were enrolled and 19 were available for review at a mean of 14.2 years (10 to 15.7) post-operatively. For these 19 patients, the mean Hospital for Special Surgery knee score was 60 (57 to 62) pre-operatively and 85 (82 to 87) at final follow-up (p < 0.001; paired t-test). The femorotibial angle and tibial inclination angle (IA) were measured at short-term follow-up, one to four years post-operatively, and showed no significant subsequent changes. The clinical scores and radiological measurements showed little change over time. One patient required conversion to total knee replacement during this time. These results suggest that the coronal angle achieved at operation is maintained at long-term follow up after HCO without alteration of the IA, providing a good long-term clinical outcome.

Cite this article: Bone Joint J 2014;96-B:467–72.

Introduction:

The diagnosis of implant-associated infections is challenging, and the conventional culturing of periprosthetic tissue has been the gold standard for diagnosis of implant-associated infections. However, conventional diagnostic tests are inaccurate because the pathogenesis of implant-associated infection is related to microorganisms growing in biofilms. We compared culture of samples obtained by sonication of explanted implants to dislodge adherent bacteria from implants with conventional culture of periprosthetic tissue. The purpose of this study is to evaluate the results of sonication that is microbiological diagnostic method for implant-associated infections.

Introduction

It is still controversial whether one or two-stage revision should be indicated for deeply infected hip prosthesis, and there are no scoring systems for the decision of them. An assessment system for the treatment of deeply infected hip prosthesis was evaluated for the patients who had undergone one or two-stage revision total hip arthroplasty (THA).

Total knee arthroplasty (TKA) increasingly is utilized to treat younger, more physically active, or more culturally diverse patients who desire the ability to perform activities with high knee flexion. As a result, many implant manufacturers have modified designs or introduced new ones to better facilitate deep knee flexion. To date, a mix of studies has reported superior or equivalent flexion performance comparing high-flexion and traditional implant designs. Importantly, many of these studies are conducted with the patient supine in non-weightbearing postures, not in functional postures where differences in joint mechanics are better manifest. The goal of this study was to evaluate weightbearing kneeling and lunging knee kinematics in patients with bilateral TKA of two types.

Nine high functioning patients from the American Southwest provided informed consent to participate in this single-surgeon study. The subjects averaged 74 years of age and included three females. Each subject received a traditional cruciate-retaining TKA in one knee and a flexion-enhanced cruciate-retaining (7 knees) or posterior-stabilized (2 knees) TKA in the other. The traditional knees were an average of 84 months postoperative and had combined Knee Society Scores averaging 183. The knees with new TKA designs were an average of 31 months postoperative and had combined Knee Society scores averaging 188. Subjects were observed performing a weight-bearing lunge to maximum comfortable flexion and partially weightbearing kneeling to maximum comfortable flexion using lateral fluoroscopy. Model-image registration techniques were used to quantify the 3D translations and rotations of the tibial and femoral components.

There were no differences in maximum knee flexion during lunging (115°±12° versus 118°±7°) or kneeling (120°±14° versus 120°±10°) for the traditional and flex-ionenhanced TKA’s. Tibial internal rotation and abduction were not different. The locations of the medial and lateral condyles were significantly more posterior in the traditional design for both activities (p< 0.05).

This study examined maximum flexion knee kinematics in clinically excellent, high performing subjects with bilateral TKA of two types. No clinically important functional differences were observed. Although flexion-enhanced designs may provide improved flexion for patients who demand it, older patients living a Western lifestyle appear to do equally well with the traditional and flexion-enhanced TKA designs.