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

Osseointegration of a hydroxyapatite-coated stem in femoral neck fractures in the over-80 s

PURPOSE

In the over-80 s, femoral bone is often osteoporotic and unlikely to be conducive to periprosthetic bone rehabitation. This observation often leads to cemented fixation for hemiarthroplasty in femoral neck fracture. Hydroxyapatite is a bioactive coating that has already demonstrated its osteoinductive properties. Our hypothesis is that hydroxyapatite enables prosthetic osseointegration in patients over 80, as well as periprosthetic cortical thickening. The objective was to evaluate the osseointegration of a hydroxyapatite-coated femoral stem in femoral neck fractures in the over-80 s, and the evaluation of the periprosthetic bone regeneration permitted by hydroxyapatite.

METHODS

This was a retrospective study. Osseointegration and periprosthetic bone regeneration were assessed on pre-operative, immediate post-operative and last follow-up radiographs with Engh score, O-SS score, cortical index, Canal Bone Ration (CBR) and Canal Fill Ratio (CFR).

RESULTS

One hundred and forty-six patients were included. At last follow-up, 99.3% (n = 145) of stems were osseointegrated. The mean Engh score was 19.9 [SD 3.1]. The mean O-SS score was 19.1 [SD 2.4], corresponding to very good osseointegration. The mean CBR at last follow-up was 0.48 [SD 0.07], corresponding to a non-osteoporotic femur. There was a significant difference with pre-operative CBR (p < 0,001). The pre-operative cortical index and the index at the last follow-up were significantly different for all levels of measurement (p < 0,001). The CFR at last follow-up was also significantly different with the post-operative CFR (p < 0,001).

CONCLUSION

This study shows the value of using a hydroxyapatite-coated stem on senile, osteoporotic bone to improve cortical thickness along the entire length of femoral bone.

Total hip arthroplasty using an alkali- and heat-treated titanium Zweymüller stem with no trochanteric shoulder: results at 5-year follow-up

BACKGROUND

A trochanteric shoulder is 1 of the characteristics of the original Zweymüller femoral stem for total hip arthroplasty (THA). There have been few clinical reports of THA using recently available versions of Zweymüller-type stems with eliminated trochanteric shoulder.

METHODS

82 consecutive THAs with a Zweymüller-type stem without trochanteric shoulder were analyzed. The stem was made of alkali- and heat-treated titanium, straight, tapered, with rectangular cross-section. Survivorship was estimated with the Kaplan-Meier method.

RESULTS

76 of 82 hips (92.7%) were followed for more than 5 years or until revision. 35 of 82 hips (42.7%), were revised and the predominant reason for revision was aseptic loosening of the femoral stem (34 of 35 hips, 97.1%). Survival with revision for any reason as the endpoint was 71.3% (95% CI, 51.8% to 80.1%) at 5 years.

CONCLUSIONS

The survival of the modified Zweymüller-type stem with no trochanteric shoulder was unacceptably low.

Effect of femoral stem surface coating on clinical and radiographic outcomes of cementless primary total hip arthroplasty: a patient-matched retrospective study

PURPOSE

This study aims to determine whether changing the stem coating grants superior outcomes at a minimum follow-up of five years.

METHODS

Retrospective review of a consecutive series of primary total hip arthroplasties (THAs) operated by direct anterior approach between 01/01/2013 and 31/12/2014. Two stems were compared, which were identical except for their surface coating; "the Original stem" was fully coated with hydroxyapatite (HA), while "the ProxCoat stem" was proximally coated with plasma-sprayed titanium and HA. Matching was performed. Clinical assessment included modified Harris hip score (mHHS), Oxford hip score (OHS), and forgotten joint score (FJS). Radiographic assessment evaluated alignment, subsidence, pedestal formation, heterotopic ossification, radiolucent lines ≥ 2 mm, spot welds, cortical hypertrophy, and osteolysis.

RESULTS

232 hips received the Original stem and 167 the ProxCoat stem, from which respectively five hips (2.2%) and no hips (0%) underwent revision. Matching identified two groups of 91 patients, with comparable patient demographics. At > five years follow-up, there were no differences in OHS (16 ± 6 vs 15 ± 5; p = 0.075) nor FJS (81 ± 26 vs 84 ± 22; p = 0.521), but there were differences in mHHS (89 ± 15 vs 92 ± 12; p = 0.042). There were no differences in alignment, subsidence, pedestal formation, heterotopic ossification, cortical hypertrophy, and osteolysis. There were differences in prevalence of proximal radiolucent lines (12% vs 0%; p < 0.001) and distal spot welds (24% vs 54%; p < 0.001).

CONCLUSION

At a minimum follow-up of five years, this study on matched patients undergoing primary THA found that ProxCoat stems results in significantly fewer radiolucent lines, more spot welds, and less revisions than Original stems, thus suggesting better bone ingrowth.

Neuro-bone tissue engineering: Multiple potential translational strategies between nerve and bone

Numerous tissue regeneration paradigms show evident neurological dependence, including mammalian fingertip, skin, and bone regeneration. The mature skeleton is innervated by an abundant nervous system that infiltrates the developing axial and appendicular bones and maintains the stability of the systemic skeletal system by controlling blood flow, regulating bone metabolism, secreting neurotransmitters, and regulating stem cell behavior. In recent years, neurotization in tissue-engineered bone has been considered as a promising strategy to effectively overcome the challenge of vascularization and innervation regeneration in the central zone of "critical-sized bone defects" that conventional tissue-engineered scaffolds are unable to handle, however, further validation is needed in relevant clinical applications. Therefore, this study reviews the mechanisms by which the nervous system regulates bone metabolism and regeneration through a variety of neurogenic or non-neurogenic factors, as well as the recent progress and design strategies of neuralized tissue-engineered bone, to provide new ideas for further studies on subsequent neural bone tissue engineering. STATEMENT OF SIGNIFICANCE: The interaction of nerve and bone tissue during skeletal development and repair has attracted widespread attention, with emerging evidences highlighting the regulation of bone metabolism and regeneration by the nervous system, but the underlying mechanisms have not been elucidated. Thus, further applications of neuro-bone tissue engineering still needs careful consideration. In this review, we summarize the numerous neurogenic and non-neurogenic factors which are involved in bone repair and regeneration, and further explore the current status of their application and biomaterial design in neuro-bone tissue engineering, and finally discuss the challenge and prospective for neuro-bone tissue engineering to facilitate its further development.

Influence of Hydroxyapatite Coating for the Prevention of Bone Mineral Density Loss and Bone Metabolism after Total Hip Arthroplasty: Assessment Using 18F-Fluoride Positron Emission Tomography and Dual-Energy X-Ray Absorptiometry by Randomized Controlled Trial

Background

Hydroxyapatite- (HA-) coated implants tend to achieve good osteoinductivity and stable clinical results; however, the influence of the coating on the prevention of bone mineral density (BMD) loss around the implant is unclear. The purpose of this randomized controlled trial was to evaluate the effectiveness of HA-coated implants for preventing BMD loss and to determine the status of bone remodeling after total hip arthroplasty (THA), making comparisons with non-HA-coated implants.

Methods

A total of 52 patients who underwent primary THA were randomly allocated to HA and non-HA groups. BMD was measured by dual-energy X-ray absorptiometry (DEXA) at 1 week postoperation to form a baseline measurement, and then 24 weeks and 48 weeks after surgery. The relative change in BMD was evaluated for regions of interest (ROIs) based on the Gruen zone classifications. ¹⁸F-fluoride positron emission tomography (PET) was performed at 24 weeks postsurgery, and the maximum standardized uptake values (SUV_max) were evaluated in the proximal (HA-coated) and distal (non-HA-coated) areas in both groups.

Results

There were significant differences in BMD loss in ROIs 3 and 6 (p = 0.03), while no significant difference was observed in ROI 7 at either 24 or 48 weeks postsurgery. There was no significant correlation between PET uptake and BMD (24 or 48 weeks) in either group.

Conclusion

The influence of a HA coating in terms of BMD preservation is limited. No significant correlation was found between BMD and SUV_max measured by PET, either with or without the use of a HA coating.