James A. D’Antonio

Ceramic bearings for total hip arthroplasty have high survivorship at 10 years.

BackgroundCeramic bearings were introduced to reduce wear and increase long-term survivorship of total hip arthroplasty. In a previous study comparing ceramic with metal-on-polyethylene at 5 to 8 years, we found higher survivorship and no osteolysis for the ceramic bearings.Questions/PurposesWe asked whether ceramic bearings have equal or superior survivorship compared with that for metal-on-polyethylene at longer followup; we also determined survivorship of the implant systems, the presence or absence of radiographic osteolysis, and incidence of device squeaking.MethodsFive surgeons at five sites have followed 189 patients (216 hips) for a minimum of 10 years and average of 10.3 years (range, 10–12.4 years) comparing alumina ceramic bearings (144 hips) with cobalt chrome-on-polyethylene bearings (72 hips). We determined Kaplan-Meier survivorship of the bearing surface and implant systems and collected radiographic and clinical data.ResultsWe observed no difference between the control metal-on-polyethylene and the alumina-bearing couple cohorts with regard to bearing-related failures (98.9% versus 99.1%). Revisions for any reason occurred in 10.5% of the control patients and 3.1% of the patients with alumina bearings. All femoral implants remain well fixed (100%), whereas one acetabular component (1%) is unstable in the control group. Osteolysis occurred in 26% of the control patients and in none of the patients with alumina bearings. Squeaking occurred in two of 144 hips (1.4%) of the patients with ceramic bearings.ConclusionsPatients receiving the ceramic-on-ceramic bearings had fewer revisions for any reason and less osteolysis than the control metal-on-polyethylene at 10 years. Our data suggest ceramic bearings continue to provide an option for the young and more active patient and provide for a measure to compare other new alternative bearings that are currently available.Level of EvidenceLevel I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Ceramic/Ceramic Total Hip Replacement: The American Experience with Stryker Implants

A major challenge for total hip arthroplasty is to minimize wear and osteolysis in young, active patients. Alumina ceramic bearings have shown superior wear resistance and lubrication and do not carry the risk of ion release. In a prospective randomized study (ABC), 514 hips were implanted. All patients (average age, 53 years) received the same press-fit hydroxyapatite coated femoral stem; two thirds (345 hips) received alumina ceramic bearings, and one third (169 hips) received a cobalt-chrome-on-polyethylene bearing. A fourth arm (Trident) was included involving use of a metal-backed acetabular component implanted in 209 patients. At a mean follow-up of 35.2 months (range, 24–48 months), there was no significant difference in clinical performance between the patient cohorts. The cohort of patients included in the ABC, Trident, and extended access portion of the study represents a population of 2313 patients with no device related failures attributable to the ceramic on ceramic articulation used in these patients. This new experience involves the use of improved ceramic materials and new design considerations that eliminate the risks and complications of past experiences with ceramic implants and provides a safe bearing option for young patients.

CORR Insights®: Wear and Osteolysis of Highly Crosslinked Polyethylene at 10 to 14 Years: The Effect of Femoral Head Size

P olyethylene has been in use as a bearing surface for hip arthroplasty for more than 60 years and many past attempts to alter its structure and improve performance have been met with complications and controversy. Increased wear of conventional polyethylene, associated periprosthetic bone loss, and the need for revision surgery peaked in the 1990s. This was in part due to younger and more active patients receiving THA, the use of larger diameter femoral heads, and also related to issues with first-generation cementless sockets. It has been generally accepted that reducing liner wear below 0.1 mm and volumetric wear below 80 cubic mm per year reduces the risk of osteolysis and can increase the longevity of hip arthroplasty. First-generation highly crosslinked polyethylenes (HXLPEs) were developed to increase abrasive wear resistance and address these issues. The major controversies and concerns with these new materials include decreased polyethylene fatigued strength, potential for in vivo oxidation, implant fracture with thin or mapositioned liners, the use of larger diameter femoral heads, and polyethylene particulate size and shape. While simulator studies predicted substantial wear reductions, including low wear for larger diameter femoral heads, the ultimate test for implant performance and survivorship remains in vivo analysis.

CORR Insights®: Primary Ceramic-on-ceramic Total Hip Arthroplasty Using a 32-mm Ceramic Head with a Titanium-alloy Sleeve

C eramic-on-ceramic bearings have become a popular alternative to conventional polyethylene in THA. The major advantages of ceramic bearings for THA include their scratch resistance, low coefficient of friction, less-reactive particulate debris, and superior wear resistance. Dating back to the 1970s, ceramic bearing failures were primarily related to aseptic implant loosening and catastrophic ceramic fractures [1]. In the 1990s, a new generation of alumina ceramic bearings became available with higher quality and greater burst strength [3]. They were also mated with implants that had excellent fixation records and high taper tolerances. Despite these advances, ceramic fracture, neck socket impingement, and squeaking remain a current concern. Fracture risk is increased with smaller diameter femoral heads, malpositioned sockets, and the presence of trunnion debris and/or damage. Impingement and squeaking are typically related to implant position, design, and material properties. A more recent concern is the use of larger diameter femoral heads on smaller trunnions. Larger-diameter femoral heads carry a greater risk of fretting corrosion and adverse local tissue responses (ALTRs). Retrievals and in vitro studies [4] have found less fretting corrosion at the head neck junction with ceramic femoral heads compared to metal heads. The addition of a Ti sleeve within the ceramic head decreases the potential risks of fracture from trunnion debris and or damage. However, the metal sleeve raises some concern regarding the potential of fretting corrosion and ALTRs. In the current study, Lim and colleagues reviewed alumina ceramic bearings utilizing a titanium alloy sleeve within the modular ceramic femoral head with a minimum 5-year followup. Currently, clinical studies utilizing alumina ceramic bearings without Ti sleeves have minimum 10-year followup [2, 5]. The principal issues to compare are survivorship revision for any reason, ceramic fracture, and incidence of osteolysis. The authors reported a 97% survivorship for revision for any reason. This is similar to survivorships ranging from 95% to 99% found by others [2, 5]. This CORR Insights is a commentary on the article ‘‘Primary Ceramic-on-Ceramic Total Hip Arthroplasty Using a 32-mm Ceramic Head with a Titanium-alloy Sleeve’’ by Lim and colleagues available at: DOI:10.1007/ s11999-015-4374-y. The author certifies that he, or any member of his immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/ licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR or The Association of Bone and Joint Surgeons. This CORR Insights comment refers to the article available at DOI:10.1007/s11999-0154374-y. J. A. D’Antonio MD (&) Greater Pittsburgh Orthopaedic Associates, 725 Cherrington Parkway, Suite 200, Moon Township, PA 15108, USA e-mail: dantonioja@me.com CORR Insights Published online: 20 June 2015 The Association of Bone and Joint Surgeons1 2015

The “Frequently Asked Questions” About Hydroxyapatite Coatings

For the past fifteen years, similar questions have been asked about HA-coated implants. We asked our advisory board to respond to five common questions about the use of hydroxyapatite in orthopaedics.