Outcomes of total hip arthroplasty using collared versus collarless uncemented HA-coated stems: a meta-analysis.

Purpose: to systematically review comparative studies reporting revision rates, clinical outcomes, or radiographic outcomes of total hip arthroplasty (THA) using collared versus collarless conventional-length uncemented hydroxyapatite (HA)-coated stems. Methods: In adherence with PRISMA guidelines, a literature search was performed on Medline, Embase, and Scopus. Comparative clinical studies were eligible if they reported outcomes of collared versus collarless uncemented HA-coated stems for primary THA. Two reviewers screened titles, abstracts, and full-texts to determine eligibility; then performed data extraction; and assessed the quality of studies according to Joanna Briggs Institute (JBI) checklist. Results: The search returned 972 records, 486 were duplicates, and 479 were excluded after title/abstract/full-text screening. Three further studies were included from the references of eligible studies and from discussions with subject matter experts, resulting in 11 included studies. The JBI checklist indicated six studies scored ≥7 points and four studies ≥4 points. Pooled data revealed collared stems had significantly lower revision rates (OR = 0.45; 95% CI = 0.31-0.64) and subsidence (MD = -1 mm; 95% CI = -1.6--0.3), but no significant difference in intraoperative complication rates (OR = 0.94; 95% CI = 0.67-1.32) in the short term to mid-term. Unpooled data indicated that collared stems provide equivalent survival, equivalent or better outcomes, and equivalent or lower complication rates. Conclusion: In comparative studies, collared stems have lower revision rates than collarless stems, as well as equivalent or better clinical and radiographic outcomes. Differences could be due to a protective effect that the collar offers against subsidence, particularly in undersized or misaligned stems. Further studies are warranted to confirm long-term results and better understand differences between registry data and clinical studies.

Survival and Clinical Outcomes at 30 to 35 Years Following Primary Total Hip Arthroplasty With a Cementless Femoral Stem Fully Coated With Hydroxyapatite.

BACKGROUND: The purpose of the present study was to update and report clinical outcomes and survival of primary total hip arthroplasty using a cementless double-tapered titanium fully hydroxyapatite-coated stem at a follow-up > 30 years. METHODS: The outcomes of this series of 347 primary total hip arthroplasties were already published at a follow-up > 25 years, during which only 12 stems were revised. Since then, there were two additional stem revisions, bringing the total to 14 stem revisions (all of which also required cup revision). Patients still living with the original stem were assessed using the modified Harris Hip Score and patient satisfaction (very satisfied, satisfied, dissatisfied, and very dissatisfied). Revision incidence was calculated using the Kaplan-Meier (KM) method and Cumulative Incidence Function (CIF) at 35 years. RESULTS: At a mean follow-up of 33 years (range, 31 to 35 years), 32 patients (34 hips) were still living with the original stem. Their mean modified Harris Hip Score was 86 points (range, 46 to 100) and all patients (100%) were very satisfied or satisfied with surgery. The revision incidence at 35 years considering (a) stem revision for any reason was 9.5% using KM and 4.5% using CIF; (b) stem revision for aseptic loosening was 3.1% using KM and 2.1% using CIF; and (c) reoperation or revision of any component for any reason was 45.3% using KM and 26.3% using CIF. CONCLUSION: The present study has demonstrated excellent survival at 35 years for a cementless double-tapered titanium fully hydroxyapatite-coated stem. LEVEL OF EVIDENCE: Level IV, Retrospective cohort study.

Long-term bone remodelling around 'legendary' cementless femoral stems.

Bone remodelling around a stem is an unavoidable long-term physiological process highly related to implant design. For some predisposed patients, it can lead to periprosthetic bone loss secondary to severe stress-shielding, which is thought to be detrimental by contributing to late loosening, late periprosthetic fracture, and thus rendering revision surgery more complicated.However, these concerns remain theoretical, since late loosening has yet to be documented among bone ingrowth cementless stems demonstrating periprosthetic bone loss associated with stress-shielding.Because none of the stems replicate the physiological load pattern on the proximal femur, each stem design is associated with a specific load pattern leading to specific adaptive periprosthetic bone remodelling. In their daily practice, orthopaedic surgeons need to differentiate physiological long-term bone remodelling patterns from pathological conditions such as loosening, sepsis or osteolysis.To aid in that process, we decided to clarify the behaviour of the five most used femoral stems. In order to provide translational knowledge, we decided to gather the designers' and experts' knowledge and experience related to the design rationale and the long-term bone remodelling of the following femoral stems we deemed 'legendary' and still commonly used: Corail (Depuy); Taperloc (Biomet); AML (Depuy); Alloclassic (Zimmer); and CLS-Spotorno (Zimmer). Cite this article: EFORT Open Rev 2018;3:45-57. DOI: 10.1302/2058-5241.3.170024.

Clinical and Radiographic Outcomes at 25-30 Years of a Hip Stem Fully Coated With Hydroxylapatite.

BACKGROUND: Little is known about the survival of total hip arthroplasty implants with bioactive coatings beyond the first 20 years. The authors aimed to report survival of a tapered hip stem fully coated with hydroxylapatite (HA) at follow-up of 25-30 years. METHODS: Of the original series of 320 patients (347 hips), 12 patients (12 hips) had stem and cup revisions, 54 patients (55 hips) had cup revisions, 17 patients (17 hips) had liner exchange. A total of 207 patients (225 hips) died with stems in place and 21 patients (24 hips) could not be reached. This left a cohort of 80 patients (86 hips) with their original stem for assessment. Survival was analyzed using the Kaplan-Meier (KM) method and cumulative incidence function (CIF). RESULTS: Considering stem revision as endpoint, the revision risk calculated using the KM method was 6.3%, whereas using the CIF it was 3.7%. Considering any reoperation as endpoint, the revision risk calculated using the KM method was 41.2%, whereas using the CIF it was 25.9%. The Harris Hip Score for 77 patients (18 hips) was 81.6 ± 15.2. Standard x-rays were available for 52 hips (49 patients), and 10 (19.2%) showed radiolucencies <2 mm thick. CONCLUSION: This study is the first to report outcomes of an HA-coated stem beyond 25 years. The survival of stem compares favorably with long-term survival of the Charnley cemented stem, and with shorter-term registry studies. The stem achieved its intended purpose of total osteointegration in the long-term, although the proximolateral region remains susceptible to radiolucencies.

Long-term Bone Remodeling in HA-coated Stems: A Radiographic Review of 208 Total Hip Arthroplasties (THAs) with 15 to 20 Years Follow-up.

We present a prospective study focused on radiographic long-term outcomes and bone remodeling at a mean of 17.0 years (range: 15 to 20) in 208 cementless fully HA-coated femoral stems (Corail, DePuy International Ltd, Leeds, UK). Total hip replacements in this study were performed by three members of the surgeon design group between 1986 and 1991. Radiographic evaluation focused on periprosthetic osteolysis, bone remodeling, osseous integration, subsidence, metaphyseal or diaphyseal load transfer, and femoral stress shielding. The radiographs were digitized and examined with contrast-enhancing software for analysis of the trabecular architecture. Radiographic signs of aseptic stem loosening were visible in two cases (1%). Three stems (1.4%) showed metaphyseal periprosthetic osteolysis in four of seven Gruen zones associated with eccentric polyethylene wear awaiting metaphyseal bone grafting and cup liner exchange. One stem (0.5%) was revised due to infection. No stem altered in varus or valgus alignment more than two degrees, and mean subsidence was 0.1 mm (range: 0 to 2 mm) after a mean of 17.0 years. A total of 5 stems (2.4%) required or are awaiting revision surgery. Trabecular orientation and micro-anatomy suggested main proximal load-transfer patterns in all except 3 cases (98.6%). Combined metaphyseal and diaphyseal osseointegration and bone remodeling were visible in 100 stems (48%). Diaphyseal stress shielding and cortical thickening were observed in 3 stems (1.4%). Other radiographic features are discussed in depth. This long-term study of 208 fully HA-coated Corail stems showed satisfactory osseointegration and fixation in 203 cases (97.6%) after a mean of 17.0 years follow-up. Stem failures were associated with extreme eccentric polyethylene wear.

Twenty-year results of the cementless Corail stem.

The concept of an extensive hydroxyapatite (HA) coating for the fixation of a tapered femoral stem (Corail®) was introduced 25 years ago in the hope that we could achieve durable biological fixation while preserving normal periprosthetic bone activity. The value of uncemented fixation using HA-coated implants is now widely admitted. However, the characteristics of implant coating and more specifically its extent still remain a subject of debate or even controversy. This prospective study conducted over a 20-year period has greatly contributed to demonstrating the reliability of the Corail® prosthesis, in terms of functional abilities, radiographic evidence and global survivorship. A full HA coating applied on a straight and proximally flared stem induces substantial short-, mid- and long-term benefits without any deleterious effects reported. Modifications of the bone pattern have been strictly limited: slight resorption at the calcar level, absence of cortical hypertrophy and alleged stress shielding. The radiological "silence" is one of the paramount facts clearly demonstrated.