Hip 716 articles
Highly crosslinked and thermally treated polyethylenes were clinically introduced to reduce wear and osteolysis. Although the crosslinking process improves the wear performance, it also introduces free radicals into the polymer that can subsequently oxidize. Thermal treatments have been implemented to reduce oxidation; however, the efficacy of these methods with regard to reducing in vivo oxidative degradation remains to be seen. Polyethylene oxidation is a concern because it can compromise the ultimate strength and ductility of the material.
Methicillin-resistant hip infections are increasingly common. Reports of the surgical management of these patients using two-stage THA show variable control of infection, but all reports used static spacers.
Do Tissues From THA Revision of Highly Crosslinked UHMWPE Liners Contain Wear Debris and Associated Inflammation?
Polyethylene wear debris is a major contributor to inflammation and the development of implant loosening, a leading cause of THA revisions. To reduce wear debris, highly crosslinked ultrahigh-molecular-weight polyethylene (UHMWPE) was introduced to improve wear properties of bearing surfaces. As highly crosslinked UHMWPE revision tissues are only now becoming available, it is possible to examine the presence and association of wear debris with inflammation in early implant loosening.
Ultrahigh-molecular-weight polyethylene (UHMWPE) is used as an articulating surface in prosthetic devices. Its failure under various mechanisms after oxidation is of utmost concern. Free radicals formed during the sterilization process using high-energy irradiation result in oxidation. Europium, an element of the lanthanide family, has a unique electron configuration with an unusual lack of preference for directional bonding and notable bonding to oxygen. Because of this, it currently is used in studies for stabilization of polymers such as polyvinyl chloride.
The iliocapsularis muscle is a little known muscle overlying the anterior hip capsule postulated to function as a stabilizer of dysplastic hips. Theoretically, this muscle would be hypertrophied in dysplastic hips and, conversely, atrophied in stable and well-constrained hips. However, these observations have not been confirmed and the true function of this muscle remains unknown.
Conversion of hip arthrodesis to a THA reportedly provides a reasonable solution, improving function, reducing back and knee pain, and slowing degeneration of neighboring joints associated with a hip fusion. Patients generally are satisfied with conversion despite the fact that range of mobility, muscle strength, leg-length discrepancy (LLD), persistence of limp, and need for assistive walking aids generally are worse than those for conventional primary THA.
Various clinical and biomechanical studies suggest certain acetabular positions may be associated with higher wear and failure rates in modern metal-on-metal hip resurfacing arthroplasties. However, there are no widely available, reliable, and cost-effective surgical techniques that ensure surgeons are able to place an acetabular component within the safe range of inclination angles after hip resurfacing surgeries.
The direct anterior approach (DAA) for hip resurfacing arthroplasty is a technically difficult approach but theoretically reduces the soft tissue trauma to the hip because it does not require muscle detachments from the bone. Furthermore, the patient is in the supine position facilitating fluoroscopy to control component placement. However, the complications associated with the learning curve and functional outcome scores are not well defined in the literature.
Metal ions released from arthroplasty devices are largely cleared in urine, leading to high exposure in renal tissues. Validated early markers of renal damage are routinely used to monitor workers in heavy metal industries, and renal risk can be quantified in these industries. It is unclear if the ion levels in patients with metal-on-metal hips are sufficient to cause renal damage.
Restoration of hip offset and leg length during THA is often limited by available implant geometries. The recent introduction of femoral components with a modular junction at the base of the neck (two modular junction components) has expanded the options to restore femoral offset and leg length.