Ten-year follow-up of an anatomical hydroxyapatite-coated total hip prosthesis

Influence of different CCD angles on osseointegration and radiological changes after total hip arthroplasty of a triple wedge shape cementless femoral stem: a prospective cohort study

PURPOSE

The purpose of this study was to evaluate the osseointegration and radiological outcomes in patients after total hip arthroplasty, hypothesizing different load patterns with one cementless stem design and different CCD angles (CLS Spotorno femoral stem 125° vs 135°).

METHODS

All cases of degenerative hip osteoarthritis fulfilling strict inclusion criteria were treated with cementless hip arthroplasty between 2008 and 2017. Ninety-two out of one hundred six cases were clinically and radiologically examined three and 12 months after implantation. Two groups with each 46 patients were rendered prospectively and compared in clinical (Harris Hip Score) and radiological outcome.

RESULTS

At final follow-up, no significant difference regarding Harris Hip Score was detected between the two groups (mean 99.2 ± 3.7 vs. 99.3 ± 2.5; p = 0.73). Cortical hypertrophy was found in none of the patients. Stress shielding was seen in a total of 52 hips (n = 27 vs. n = 25; 57% of the 92 hips). No significant difference regarding stress shielding was detected when comparing both groups (p = 0.67). Significant bone density loss was detected in Gruen zone one and two in the 125° group. The 135° group showed significant radiolucency in Gruen zone seven. No overall radiological loosening or subsidence of the femoral component was observed.

CONCLUSION

According to our results, the use of a femoral component with a 125° CCD angle versus a 135° CCD did not result in a different osseointegration and load transfer with a clinically relevant significance.

Electrophoretic deposition of collagen-reinforced HA/CTS biocomposite coatings

In this study, the biomimetic approach described as reverse engineering by trying to copy the excellent concepts of nature and taking nature as a model has been used. In order to mimic the structure of natural bone, hydroxyapatite (HA), chitosan (CTS) and collagen have been combined as a novel type of biocomposite coating. HA/CTS/collagen biocomposite coatings have been successfully electrophoretically deposited on Ti6Al4V biomedical implants. A novel type of a polyelectrolyte consisting of ethanol, water and isopropyl alcohol has been used for the electrophoretic deposition process. The effect of collagen concentration on the structural and corrosion protection performance of the biocomposite coatings has been investigated by X-ray diffraction, field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, potentiodynamic polarization (Tafel extrapolation) and electrochemical impedance spectroscopy techniques. The electrophoretically deposited HA/CTS/collagen biocomposite coatings have exhibited corrosion protection against simulated physiological body fluid up to five times better than that of bare Ti6Al4V alloy.

Efficacy of risedronate in improving bone mineral density in patients undergoing total hip arthroplasty: A meta-analysis of randomized controlled trials

BACKGROUND

Risedronate is widely used in the therapy of osteoporosis and other metabolic bone diseases. This meta-analysis was aimed to assess whether administration risedronate could increase the bone mineral density (BMD) in patients undergoing primary total hip arthroplasty (THA).

METHODS

Electronic databases: PubMed, EMBASE, Web of Science, Cochrane Library, and Chinese Wanfang database were searched for all relevant studies. Inclusion criterion was that patients prepared for THA and use risedronate as intervention group and placebo as control group. BMD change in Gruen zone 1 and 7 were primary outcomes. Meta-analysis was performed using Stata 12.0 software.

RESULTS

Six RCTs were finally included in this meta-analysis. Compared with control group, risedronate has a beneficial role in increasing BMD in Gruzen 1, 2 6, and 7 at 3 months (P < .05). Oral risedronate has a beneficial role in preservation of BMD in all of the Gruen zones at 6 and 12 months (P < .05). Moreover, oral risedronate could significantly increase the Harris hip scores and bone alkaline phosphatase than control group (P < .05).

CONCLUSION

Oral risedronate has an effect on the preservation of periprosthetic BMD in proximal regions (Gruen zone 1, 2, 3, and 7) at 3 months and all of the regions at 6 and 12 months after THA.

Oral risedronate increases Gruen zone bone mineral density after primary total hip arthroplasty: a meta-analysis

BACKGROUND

This meta-analysis was performed to assess the efficacy of risedronate in increasing bone mineral density (BMD) in patients undergoing primary total hip arthroplasty (THA).

METHODS

We systematically searched the following databases: PubMed, Embase, Web of Science, Cochrane Library, and Chinese Wanfang database from inception up to October 2017. Included patients were prepared for THA and were separated into two groups: intervention group (risedronate treatment) and control group (placebo treatment). BMD change in Gruen zone 1 and 7 were primary outcomes. Meta-analysis was performed using Stata 12.0 software.

RESULTS

Five randomized controlled trials (RCTs) involving 259 patients (risedronate group = 127, control group = 132) were finally included in this meta-analysis. Meta-analysis indicated that oral risedronate significantly increased the BMD change in Gruen zone 1. However, there was little clinical significance between the risedronate and control group in terms of the Gruen zones 2, 3, and 7. Oral risedronate significantly increased the Harris hip scores compared with the control group (P < 0.05).

CONCLUSION

Oral risedronate could significantly reduce peri-prosthetic bone resorption around an uncemented femoral stem (Gruen zone 1) after THA. Due to the limited included studies, more high-quality randomized controlled trials (RCTs) were still needed to identify the efficacy of risedronate for bone loss in THA.

Early subsidence of shape-closed hip arthroplasty stems is associated with late revision. A systematic review and meta-analysis of 24 RSA studies and 56 survival studies

BACKGROUND AND PURPOSE

Few studies have addressed the association between early migration of femoral stems and late aseptic revision in total hip arthroplasty. We performed a meta-regression analysis on 2 parallel systematic reviews and meta-analyses to determine the association between early migration and late aseptic revision of femoral stems.

PATIENTS AND METHODS

Of the 2 reviews, one covered early migration data obtained from radiostereometric analysis (RSA) studies and the other covered long-term aseptic revision rates obtained from survival studies with endpoint revision for aseptic loosening. Stems were stratified according to the design concept: cemented shape-closed, cemented force-closed, and uncemented. A weighted regression model was used to assess the association between early migration and late aseptic revision, and to correct for confounders. Thresholds for acceptable and unacceptable migration were determined in accordance with the national joint registries (≤ 5% revision at 10 years) and the NICE criteria (≤ 10% revision at 10 years).

RESULTS

24 studies (731 stems) were included in the RSA review and 56 studies (20,599 stems) were included in the survival analysis review. Combining both reviews for the 3 design concepts showed that for every 0.1-mm increase in 2-year subsidence, as measured with RSA, there was a 4% increase in revision rate for the shape-closed stem designs. This association remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. The threshold for acceptable migration of shape-closed designs was defined at 0.15 mm; stems subsiding less than 0.15 mm in 2 years had revision rates of less than 5% at 10 years, while stems exceeding 0.15 mm subsidence had revision rates of more than 5%.

INTERPRETATION

There was a clinically relevant association between early subsidence of shape-closed femoral stems and late revision for aseptic loosening. This association can be used to assess the safety of shape-closed stem designs. The published research is not sufficient to allow us to make any conclusions regarding such an association for the force-closed and uncemented stems.

Long-term outcomes of a new model of anatomical hydroxyapatite-coated hip prosthesis

This prospective study was designed to evaluate 196 Anatomique Benoist Giraud (ABG II) total hip arthroplasties which were implanted between September 1999 and December 2000. A minimum 11 years follow up was completed in 183 cases. The bearing surfaces were polyethylene-zirconia in 84 cases, polyethylene-metal in 42 and ceramic-ceramic in 57. Changes in the femoral stem design, in relation to the previous ABG I model, have led to a significant improvement in stress-shielding. Polyethylene wear rate was lower by more than 50% compared with non-crosslinked polyethylene. Excellent and good results were obtained in 90.32% of cases, and implant survival was 98.39% at the end of follow-up.

Extensive osteolysis caused by polyethylene particle migration in an anatomical hydroxyapatite-coated hip prosthesis: 10 years' follow-up

We report our 10-year follow-up results of 630 consecutive Anatomique Benoist Giraud I hip prostheses implanted between June 1990 and December 1995. At this time, 520 were satisfactory and 25 had been revised. Although the majority of patients remained asymptomatic at the end of follow-up, the real survivorship of the implant was less than 91% (33 patients who were in the waiting list for revision due to osteolysis at that time were revised by December 2007). On the other hand, radiographic outcomes were of concern: around 90% of patients showed progressive stress shielding and large granulomatous lesions in the proximal femur, and more than 82% of patients exhibited polyethylene wear in excess of 1 mm (mean=1.69 mm).

Inferior survival of hydroxyapatite versus titanium-coated cups at 15 years

Hydroxyapatite (HA) particles have long been suspected to disintegrate from implant surfaces, become entrapped in joint spaces of orthopaedic bearing couples, and start a cascade leading to progressive polyethylene (PE) wear, increased osteolysis, and aseptic loosening. We compared cup revision at 15 years' followup in a randomized group of patients with 26 cementless THA components with titanium (Ti) versus first-generation HA coating. We also assessed radiographic PE wear and osteolysis to the 12-year followup or end point revision at a minimum of 5 years (mean, 10.9 years; range, 5-12.6 years). Two Ti-coated cups (17%) and eight HA-coated cups (57%) were revised at 15 years' followup. Femoral head penetration rate was 0.46 mm/year (standard deviation, 0.26) with the HA-coated cups (n = 12) and 0.38 mm/year (standard deviation, 0.14) with the Ti-coated cups (n = 10); we observed a wide variance of linear wear with the HA-coated cups. We also observed a positive association between high wear rate and revision, and between a high volume of osteolysis and revision. Our findings suggest inferior survival of medium-thickness spray-dried HA-coated cups with individual cases of excessive PE wear and premature cup failure. These findings apply to first-generation modular cups and may not apply to other cup designs and new HA-coating technologies.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

High revision rate of hydroxyapatite-coated ABG-I prosthesis

BACKGROUND

The aim of this study was to investigate the causes of the high revision rate of the hydroxyapatite-coated Anatomique Benoist Girard (ABG-I) prosthesis.

METHODS

We performed 204 total hip arthroplasties (THAs) at our hospital between March 1992 and December 1996. Of the 204 THA patients, 129 were followed up; the mean duration of follow-up was 12.2 years (range 10.0-14.5 years). There were 113 male patients and 16 female patients, with an average age of 53 years (30-83 years) at the time of surgery. The reasons for THA were avascular necrosis in 119 hips, acetabular dysplasia in 8 hips, and traumatic arthritis in 2 hips.

RESULTS

The Harris hip score was 47.3 preoperatively and 86.4 at the last follow-up. The linear polyethylene wear was an average of 0.29 mm/year. Acetabular osteolysis was seen in 113 cases (88%). Altogether, 61 (47.2%) acetabular cups were revised for aseptic loosening in 38 hips, polyethylene wear and osteolysis in 20 hips, recurrent dislocation in 2 hips, and deep infection in 1 hip. Femoral osteolysis was observed in 100 cases (77.5%). The femoral stem was revised in 4 hips (3.1%).

CONCLUSION

We observed that the fatal detriment to ABG-I acetabular cup survival in long-term follow-up was periacetabular osteolysis followed by aseptic loosening.

Comparison between DEXA and finite element studies in the long-term bone remodeling of an anatomical femoral stem

The implantation of a cemented or cementless femoral stem changes the physiological load transfer on the femur producing an effect on the bone called adaptative remodeling. The patterns of this remodeling are attributed to mechanical and biological factors, and those changes in bone mineral density have been determined in long-term densitometry studies. This technique has proved to be a useful tool able to quantify small changes in bone density in different femoral areas, and it is considered to be ideal for long-term studies. On the other hand, the finite element (FE) simulation allows the study of the biomechanical changes produced in the femur after the implantation of a femoral stem. The aim of this study was to contrast the findings obtained from a 5 year follow-up densitometry study that used a newly designed femoral stem (73 patients were included in this study), with the results obtained using a finite element simulation that reproduces the pattern of load transfer that this stem causes on the femur. In this study we have obtained a good comparison between the results of stress of FE simulation and the bone mass values of the densitometry study establishing a ratio between the increases in stress (%) versus the increases in bone density (%). Hence, the changes in bone density in the long term, compared with the healthy femur, are due to different load transfers after stem implantation. It has been checked that in the Gruen zone 7 at 5 years, the most important reduction in stress (7.85%) is produced, which coincides with the highest loss of bone mass (23.89%). Furthermore, the simulation model can be used with different stems with several load conditions and at different time periods to carry out the study of biomechanical behavior in the interaction between the stem and the femur, explaining the evolution of bone density in accordance to Wolff's law, which validates the simulation model.

Risk factors for accelerated polyethylene wear and osteolysis in ABG I total hip arthroplasty

We analysed data from 155 revisions of identical cementless hip prostheses to determine the influence of patient-, implant- and surgery-related factors on the polyethylene wear rate and size of periprosthetic osteolysis (OL). This was calculated by logistic regression analysis. Factors associated with an increased/decreased wear rate included position of the cup relative to Kohler's line, increase in abduction angle of the cup, traumatic and inflammatory arthritis as a primary diagnosis, and patient height. Severe acetabular bone defects were predicted by an increased wear rate (odds ratio, OR = 5.782 for wear rate above 200 mm(3)/y), and increased height of the patient (OR = 0.905 per each centimetre). Predictors of severe bone defects in the femur were the increased wear rate (OR = 3.479 for wear rate above 200 mm(3)/y) and placement of the cup outside of the true acetabulum (OR = 3.292). Variables related to surgical technique were the most predictive of polyethylene wear rate.

Poor survival of ABG I hip prosthesis in younger patients

BACKGROUND

Hydroxyapatite coated (HAC) hip implants have been used in clinical practice for more than two decades. However, the majority of studies have reported only intermediate term outcomes that are not reliable for predicting long-term behavior in all implants. The aim of this study was to determine the performance of HAC total hip arthroplasty in younger patients over a 10-year follow-up period.

METHODS AND RESULTS

This was an observational retrospective study of a 137 consecutive hips with the ABG I prosthesis. Of these, 128 were available for the last investigation. Median duration of follow-up was 10.9 years. The mean age at time of index surgery was 46+/-6.7 years. Probability of implant survival was estimated using the Kaplan-Meier method. The overall 12-year cumulative survival was 0.55 (95% CI, 0.443-0.659). Periprosthetic osteolysis (57 %) was the most frequent reason for failure followed by aseptic loosening (28 %). When only aseptic loosening was included in the analysis, the same figures for cup and stem were 0.873 (95% CI, 0.808-0.938) and 0.992 (95% CI, 0.976- 1.0), respectively. Patients with a smaller cup size were those at high risk for revision due to wear-related complications (odds ratio, OR=4.3; 95% CI, 1.734-10.555).

CONCLUSION

This study reports one of the poorest 12-year survivorship data for cementless acetabular component in the literature. The main reason for premature failure was osteolysis, strongly related to high wear rate of polyethylene.

Long-term study of bone remodelling after femoral stem: A comparison between dexa and finite element simulation

A hip replacement with a cemented or cementless femoral stem produces an effect on the bone called adaptive remodelling, attributable to mechanical and biological factors. The objective of all of cementless prostheses designs has been to achieve a perfect transfer of loads in order to avoid stress-shielding, which produces an osteopenia. In order to quantify this, the long term and mass-produced study with dual energy X-ray absorptiometry (DEXA) is necessary. Finite element (FE) simulation makes possible the explanation of the biomechanical changes which are produced in the femur after stem implantation. The good correlation obtained between the results of the FE simulation and the densitometric study allow, on one hand, to explain from the point of view of biomechanical performance the changes observed in bone density in the long-term, where it is clear that these are due to a different transfer of load in the implanted model compared to the healthy femur; on the other hand, it validates the simulation model, in a way that it can be used in different conditions and at different time periods, to carry out a sufficiently precise prediction of the evolution of the bone density from the biomechanical behaviour in the interaction between the prosthesis and femur.