The Absence of Hydroxyapatite Coating on Cementless Acetabular Components Does Not Affect Long-Term Survivorship in Total Hip Arthroplasty

Head, acetabular liner composition, and rate of revision and wear in total hip arthroplasty: a Bayesian network meta-analysis

Total hip arthroplasty (THA) is a common procedure for patients suffering from hip pain e.g. from osteoarthritis, osteonecrosis, or hip fractures. The satisfaction of patients undergoing THA is influenced by the choice of implant type and material, with one key factor being the selection of the appropriate material combination for the bearing surface. In this Bayesian network meta-analysis, we investigated the impact of material combinations for the bearing surface on the longevity of hip implants. The wear penetration rate per year and the total wear penetration in the liner resulting from different material combinations, as well as the survival rate at last follow-up, were examined. We analyzed a total of 663,038 THAs, with 55% of patients being women. Mean patient age was 59.0 ± 8.1 years and mean BMI 27.6 ± 2.6 kg/m2. The combination of an aluminium oxide (Al2O3) head and an Al2O3 liner demonstrated the lowest wear penetration at last follow-up and the lowest rate of wear penetration per year. Additionally, the combination of a crosslinked polyethylene (XLPE) liner and a zircon oxide (ZrO2) head demonstrated the lowest rate of revision at last follow-up. These findings underscore the importance of careful material selection for hip implant bearing surfaces to optimize their longevity and patient satisfaction after THA.

Risk factors for liner wear and head migration in total hip arthroplasty: a systematic review

Total hip arthroplasty (THA) is a successful orthopaedic surgical procedure, and its longevity depends on bearing components and implant fixation. Optimizing polyethylene and ceramics has led to improved wear parameters and contributed to improved long-term outcomes. The present systematic review investigated whether time span from implantation, patient characteristics and performance status exert an influence on liner wear and head migration in THA. This study was conducted in conformity to the 2020 PRISMA guidelines. All the clinical investigations which reported quantitative data on the amount of liner wear and head migration in THA were considered. Only studies which reported quantitative data at least on one of the following patient characteristics were suitable: mean age, mean BMI (kg/m2), sex, side, time span between the index THA and the last follow-up (months) were eligible. A multiple linear model regression analysis was employed to verify the association between patient characteristics and the amount of liner wear and/or head migration. The Pearson Product-Moment Correlation Coefficient was used to assess the association between variables. Data from 12,629 patients were considered. The mean length of the follow-up was 90.5 ± 50.9 months. The mean age of patients at surgery was 58.4 ± 9.4 years, and the mean BMI was 27.2 ± 2.5 kg/m2. 57% (7199 of 12,629 patients) were women, and in 44% (5557 of 12,629 patients) THAs were performed on the left. The mean pre-operative Harris hip score was 46.5 ± 6.0 points. There was evidence of a moderate positive association between the amount of liner wear and the time elapsed between the index surgery to the follow-up (P = 0.02). There was evidence of a moderate positive association between the amount of head migration and the time elapsed between the index surgery to the follow-up (P = 0.01). No further statistically significant association was found. The time elapsed between the index surgery to the follow-up was the most important factor which influence the head migration and liner wear in THA. Patients' characteristics and preoperative physical activity did not influence the amount of head migration and liner wear.

There Are over 60 Ways to Produce Biocompatible Calcium Orthophosphate (CaPO4) Deposits on Various Substrates

A The present overview describes various production techniques for biocompatible calcium orthophosphate (abbreviated as CaPO4) deposits (coatings, films and layers) on the surfaces of various types of substrates to impart the biocompatible properties for artificial bone grafts. Since, after being implanted, the grafts always interact with the surrounding biological tissues at the interfaces, their surface properties are considered critical to clinical success. Due to the limited number of materials that can be tolerated in vivo, a new specialty of surface engineering has been developed to desirably modify any unacceptable material surface characteristics while maintaining the useful bulk performance. In 1975, the development of this approach led to the emergence of a special class of artificial bone grafts, in which various mechanically stable (and thus suitable for load-bearing applications) implantable biomaterials and artificial devices were coated with CaPO4. Since then, more than 7500 papers have been published on this subject and more than 500 new publications are added annually. In this review, a comprehensive analysis of the available literature has been performed with the main goal of finding as many deposition techniques as possible and more than 60 methods (double that if all known modifications are counted) for producing CaPO4 deposits on various substrates have been systematically described. Thus, besides the introduction, general knowledge and terminology, this review consists of two unequal parts. The first (bigger) part is a comprehensive summary of the known CaPO4 deposition techniques both currently used and discontinued/underdeveloped ones with brief descriptions of their major physical and chemical principles coupled with the key process parameters (when possible) to inform readers of their existence and remind them of the unused ones. The second (smaller) part includes fleeting essays on the most important properties and current biomedical applications of the CaPO4 deposits with an indication of possible future developments.

Comparison of early femoral bone remodeling and functional outcome after total hip arthroplasty using the SL-PLUS MIA stem with and without hydroxyapatite coating

BACKGROUND

Few reports have evaluated the use of hydroxyapatite (HA) coating in SL-MIA-type stems in total hip arthroplasty (THA). Here, we compared early femoral bone remodeling after total hip arthroplasty using the SL-PLUS MIA stem with and without hydroxyapatite coating.

METHODS

From February 2012 to March 2017, 132 patients (150 hips) (HA group: 48 patients [52 hips], non-HA group: 84 patients [98 hips]) underwent THA with an SL-PLUS MIA stem. The mean follow-up duration was 3.7 years (standard deviation 1.2, range: 1.0-6.1). The Harris Hip Score (HHS), postoperative bleeding volume measurements and plain radiographs were used for clinical and radiological follow-up evaluations. Peri-prosthetic bone mineral density changes were measured by dual-energy X-ray absorptiometry.

RESULTS

At 1 year, the HHS improved from 44.4 points preoperatively to 89.2 points postoperatively and from 44.5 points to 89.7 points in the HA and non-HA groups, respectively. At 1 year postoperatively, subsidence (≧ 3 mm) occurred in 0% and 8.2% of the HA and non-HA groups, respectively. Stress shielding (≧ Grade 3) occurred in 0% and 6% of the HA and non-HA groups, respectively. The radiolucent line was significantly smaller in the HA than in the non-HA group. There was no significant difference in the bone mineral density distribution in the two groups.

CONCLUSION

Addition of HA to the SL-MIA stem can help enhance the initial fixation and early osseointegration. Further studies are required on the long-term effects of adding HA to reduce stress shielding of the proximal area of the stem.

Bioinspired surface modification of orthopedic implants for bone tissue engineering

Biomedical implants have been widely used in various orthopedic treatments, including total hip arthroplasty, joint arthrodesis, fracture fixation, non-union, dental repair, etc. The modern research and development of orthopedic implants have gradually shifted from traditional mechanical support to a bioactive graft in order to endow them with better osteoinduction and osteoconduction. Inspired by structural and mechanical properties of natural bone, this review provides a panorama of current biological surface modifications for facilitating the interaction between medical implants and bone tissue and gives a future outlook for fabricating the next-generation multifunctional and smart implants by systematically biomimicking the physiological processes involved in formation and functioning of bones.

Bone ongrowth of a cementless silver oxide-containing hydroxyapatite-coated antibacterial acetabular socket

BACKGROUND

The silver oxide-containing hydroxyapatite-coated socket (KYOCERA, Osaka, Japan) is a cementless antibacterial implant that has both the osteoconductivity of the HA and the antibacterial activity of silver. The silver oxide-containing hydroxyapatite coating was shown to have good osteoconductivity and new bone formation in vitro and in vivo. However, the histological bone ongrowth of this implant has not been proven in a clinical study.

METHODS

We analyzed bone ongrowth using two silver oxide-containing hydroxyapatite-coated sockets that were removed in revision total hip arthroplasty for recurrent dislocation. A histomorphometric analysis was performed using a scanning electron microscope (SEM) connected to a CCD camera and an elemental analysis was performed by energy-dispersive elemental spectrometry (EDS).

RESULT

A white structure thought to be osseous tissue was attached to the retrieved socket surface macroscopically, and histological bone ongrowth of the silver oxide-containing hydroxyapatite coating of the socket was confirmed by SEM. In addition, the presence of silver in the silver oxide-containing hydroxyapatite coating was confirmed in an elemental analysis by EDS.

CONCLUSION

Histologically, the silver oxide-containing hydroxyapatite-coated socket presented bone ongrowth in this clinical study.

Does hydroxyapatite coating of uncemented cups improve long-term survival? An analysis of 28,605 primary total hip arthroplasty procedures from the Nordic Arthroplasty Register Association (NARA)

OBJECTIVE

It is unclear whether hydroxyapatite (HA) coating of uncemented cups used in primary total hip arthroplasty (THA) improves bone ingrowth and reduces the risk of aseptic loosening. We therefore investigated survival of different uncemented cups that were available with or without HA coating.

METHOD

We investigated three different cup types used with or without HA coating registered in the Nordic Arthroplasty Register Association (NARA) database that were inserted due to osteoarthritis (n = 28,605). Cumulative survival rates and adjusted hazard ratios (HRs) for the risk of revision were calculated.

RESULTS

Unadjusted 13-year survival for cup revision due to aseptic loosening was 97.9% (CI: 96.5-99.4) for uncoated and 97.8% (CI: 96.3-99.4) for HA-coated cups. Adjusted HRs were 0.66 (CI 0.42-1.04) for the presence of HA coating during the first 10 years and 0.87 (CI 0.14-5.38) from year 10-13, compared with uncoated cups. When considering the endpoint cup revision for any reason, unadjusted 13-year survival was similar for uncoated (92.5% [CI: 90.1-94.9]) and HA-coated (94.7% [CI: 93.2-96.3]) cups. The risk of revision of any component due to infection was higher in THA with HA-coated cups than in THA with uncoated cups (adjusted HR 1.4 [CI 1.1-1.9]).

CONCLUSIONS

HA-coated cups have a similar risk of aseptic loosening as uncoated cups, thus the use of HA coating seems to not confer any added value in terms of implant stability. The risk of infection seemed higher in THA with use of HA-coated cups, an observation that must be investigated further.