Total hip arthroplasty (THA) is one of the most successful surgical procedures; several bearing technologies have been used, however none of these is optimal. Metal on polycarbonate-urethane (PCU) is a new bearing technology with several potential advantages: PCU is a hydrophilic soft pliable implant quite similar in elasticity to human cartilage, offers biostability, high resistance to hydrolysis, oxidation, and calcification, no biodegradation, low wear rate and high corrosion resistance and can be coupled with large metal heads (Tribofit Hip System, THS). The aim of this prospective study was to report the survivorship and the clinical and radiographic outcomes and the metal ions dosage of a group of patients operated with metal on PCU arthroplasty featuring large metal diameter heads, at 5 years from surgery. 68 consecutive patients treated with the THS were included. The patients have been contacted by phone call and invited to return to our centre for clinical (Oxford Hip Score, OHS, and Harris Hip Score, HHS), radiographic exam and metal ion levels evaluation. All the patients were operated with uncemented stems.Objectives
Study Design & Methods
The aim of this study is to analysis the ability of these patients, treated with MOMHR, to resume sport activities by gait analysis and clinical evaluations. Metal on metal hip resurfacing (MOMHR) is indicated to treat symptomatic hip osteoarthritis in young active patients. These patients require a high level of function and desire to resume sport activities after surgery. 30 consecutive male patients playing high impact sports with unilateral hip osteoarthritis and normal contralateral hip were included in the study, they were treated with MOMHR by the same surgeon. No patients were lost to follow. The mean age at operation was 39.1 years (range 31 to 46). Primary diagnosis was osteoarthritis. OHS, HHS, UCLA activity score were completed at pre-operative time, six months and one year after surgery. Functionally, gait analysis was performed in all patients 6 months and one year after surgery. A stereophotogrammetric system (Smart-DX, BTS, Milano, Italy, 10 cameras, 250Hz) and two platforms (9286BA Kistler Instrumente AG, Switzerland) were used. Cluster of 4 markers were attached on the skin of each bone segment, a number of anatomical landmarks were calibrated and segment anatomical frames defined, markers were positioned by the same operator. Walking, running and squat jump were analyzed and strength and range of movement of the hips and knees were calculated.Background
Study Design & Methods
The aim of this study was to analyze the results of our series of female patients treated with <48 mm MOMHR devices at a minimum follow-up of 5 years, to understand which is the most important aspects affecting the results and to define if the metal ions dosage has to be indicated as a routinely follow-up. This is a retrospective clinical study; the cohort included 198 consecutive MOMHR implanted in 181 female patients (17 bilateral procedures). All operations were performed between 2002 and 2011. All operations were performed by the senior surgeon. Indications to MOMHR included primary or secondary osteoarthritis (OA), rheumatoid arthritis and avascular necrosis. Contraindications included poor proximal femoral bone stock (T-score<−2.5sd in BMD of the femoral neck) or severely distorted hip anatomy. All patients were advised to underwent clinical and radiological review with the operating surgeon at 5 weeks, 3, 6 and 12 months postoperatively and then every subsequent 2 years.182 patients answered to our phone calls; 4 patients died (one of them was operated bilaterally) for causes not related to the study, and in 11 cases the phone number was expired. The minimum follow-up was 5.0 years (mean 7.5, maximum 13.2, sd 0.11).Introduction
Methods
Metal-on-polycarbonate urethane (MPU) is a cutting-edge new bearing technology for hip arthroplasty. The acetabular component consists of a 2.7mm-thick polycarbonate-urethane liner inserted into a specially manufactured uncemented titanium shell coated with hydroxyapatite [(HA) Fig. 1]. The liner is pliable and biomechanically mimics human cartilage. In vitro studies have shown minimal wear, fluid film lubrication, physiological load transmission and shock absorption capacity equal to the normal hip. This system includes prosthetic heads of a diameter 12mm less than the socket diameter. The aim of this study was to clinically assess patients treated with this novel technology in a retrospective single centre study. Twenty-seven patients with osteoarthritis treated with MPU bearing arthroplasty were included. Mean patient age was 67.9±10.35 years (44–84). Sixteen patients were female and 11 were male. Twenty-four of these had an uncemented HA-coated stem while 3 had a hip resurfacing metal femoral component. All patients were operated on by a single surgeon using a postero-lateral approach.Introduction
Methods
A retrospective single-center review has been performed to gather clinical data on the use of polycarbonate-urethane (PCU) as an articulating bearing material inside a cobalt-chrome (Co-Cr) press-fit acetabular shell. As of January 2010, the Co-Cr shell and PCU liner have been implanted into 25 total hip patients which were retrospectively followed. The indications for use were in 24 cases of osteoarthritis, and 1 revision case. No patient was lost to follow-up. The average follow-up time was 17.6 months (range 8-27). The average age of these patients was 67.9 (range 44-84), the sex distribution was 14 female and 11 male patients, of whom 15 were right and 10 left side. 24 patients received a total hip replacement with the metal acetabular system and a cementless femoral stem and 1 patient received the metal acetabular shell coupled to a cemented resurfacing head. None of the cases has had a dislocation, revision, dislodgement, or infection. At follow-up, the mean Harris hip score was 98 points (80-99). X-rays showed good bone-implant contact without any osteolysis or bone rarefaction. A detailed review of the clinical data of these patients shows that a PCU liner inserted into a Co-Cr acetabular shell is as safe and effective as other commonly used acetabular shells in other total hip systems currently available. No new or unintended adverse or device-related events were discovered with the clinical use of PCU in a Co-Cr acetabular shell.
