Periprosthetic Bone Mineral Density Research Articles

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

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). 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. 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). 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.

Periprosthetic bone quality affects the fixation of anatomic glenoids in total shoulder arthroplasty: in vitro study

Glenoid loosening, a common complication of shoulder arthroplasty, could relate to implant design and bone quality. However, the role of bone density has not been tested experimentally yet. In this study, tests on cadaveric specimens of varying bone density were performed to evaluate the effects of bone quality on loosening of typical anatomic glenoid implants. Cadaveric scapulae scanned with a quantitative computed tomography scanner to determine bone mineral density (BMD) were implanted with either pegged or keeled cemented glenoid components and tested under constant glenohumeral load while a humeral head component was moved cyclically in the inferior and superior directions. Implant superior and inferior edge lifting, defined as displacement from the underlying bone, was measured with linear variable differential transducers until we reached 23,000 test cycles, and statistical testing was performed for differences in edge lifting due to implant design and related to periprosthetic BMD. Edge lifting was statistically significant at all time points, but on average, implant design had no effect. Lifting was highest in specimens in which BMD below the lifting edge was lower, with trends of increased displacement with decreased BMD. Implant lifting was greater in glenoids of lower bone density for both implant designs. This finding suggests that fixation failure will most likely occur in bone of lower density and that the fixation design itself may play a secondary role.

Patient-specific mobility assessment to monitor recovery after total hip arthroplasty.

Total hip arthroplasty is a ubiquitously successful orthopedic surgical procedure, whose prevalence is rising worldwide. While many investigations focus on characterizing periprosthetic pathophysiology, the objective of our research is to develop and describe multi-metric assemblies as a first step toward creating a patient-specific mobility index that rehabilitators and orthopedic surgeons can utilize for prescribing their respective procedures. In total, 48 total hip arthroplasty patients (both cemented and uncemented) undergoing unilateral, primary surgery went through computed tomographic scans and gait analysis measurements both before and 1 year following their surgery. Altogether, the reported quantitative metrics include 11 spatial and temporal gait parameters, muscle density, and electromyography signals from the rectus femoris, vastus lateralis, and vastus medialis, and bone mineral density values from bioimage analysis around the implant stem. We found that measured parameters from a subgroup were sensitive to changes observed during patient recovery, implicating the predictive sensitivity of these patient conditions. Most post-operative gait parameters changed significantly, while electromyography data indicated few significant differences. Moreover, results from bioimage analyses indicate a general reduction of periprosthetic bone mineral density after 1 year, in association with increasing density of the quadriceps muscles. Furthermore, this work identifies which quantitative metrics undergo the greatest variation after total hip arthroplasty and demonstrates the clinical feasibility of a multimodal approach to mobility assessment that may ultimately support decision-making for post-surgical rehabilitation protocols.

Periprosthetic Bone Mineral Density Changes After Implantation of a Curved Bone Preserving Hip Stem Compared to a Standard Length Straight Stem: 5-Yr Results of a Prospective, Randomized DXA-Analysis

Introduction: The objective of this prospective, randomized study was to evaluate differences in periprosthetic bone mineral density changes in the proximal femur after implantation of a cementless bone preserving stem (Fitmore) compared to a cementless straight stem (CLS Spotorno). Methodology: Periprosthetic bone mineral density was measured in 140 patients (aged 33–74 yr) before surgery, 7 d, 3, 12, and 60 mo postoperatively, using dual energy X-ray absorptiometry. The 1-yr results have already been published. The results of the first postoperative measurement served as the baseline value. Because of the different length of the 2 implants we used adapted Gruen zones to divide the periprosthetic bone in seven regions of interest with comparable length. Clinical results were recorded using the Western Ontario and McMaster Universities Arthritis Index and the Harris hip score. Results: Clinical findings showed comparable results in both groups at all follow-ups (p > 0.05). A total of 5 yr after surgery, the comparison of periprosthetic bone mineral density changes showed significant differences in regions of interests 3 (CLS −3.9% vs Fitmore −0.2%, p < 0.001) and 5 (CLS −3.6% vs Fitmore −1.3%, p = 0.0028) between both implants. Conclusion: Despite the fact that no exclusive proximal load distribution could be observed, proximal periprosthetic bone loss in the proximal femur was less pronounced after implantation of the bone preserving stem than with the straight stem.

Periprosthetic Bone Mineral Density Around Uncemented Titanium Stems in the Second and Third Decade After Total Hip Arthroplasty: A DXA Study After 12, 17 and 21 Years.

Implant failure and periprosthetic fractures because of periprosthetic bone loss are a major concern in total hip arthroplasty (THA). Hardly any clinical data exist on the long-term evolution of bone mineral density (BMD) around uncemented femoral implants. The question to address is whether relevant bone loss continues into third decade around well-fixed uncemented femoral implants. BMD around stable uncemented straight titanium femoral implants was assessed in a longitudinal cohort study. We included 142 hips of 128 patients and measured the development of the periprosthetic BMD using dual-energy X-ray absorptiometry. The baseline measurement was 12years (t1) after the implantation of an uncemented femoral stem. Follow-up-measurements were performed at 17 (t2) and at 21years (t3) after primary THA. The regions of interest (ROI) were selected conforming to Gruen et al. We acquired complete data including three consecutive measurements (t1, t2, t3) for 42 patients (49 hips). Performing radiographic evaluation at t1, t2 and t3, we found a regular bone-implant interface present in all cases. Significant decrease in BMD could be shown in ROI 1 (p = 0.0001; - 7.8%), 4 (p = 0.024; - 2.4%), 6 (p = 0.001; - 5.5%) and 7 (p < 0.0001; - 11.7%) between t1 and t3 and in ROI 1 (p = 0.002; - 3.7%), 2 (p = 0.046; - 3.6%), 4 (p = 0.002; - 2.7%) and 7 (p < 0.0001; - 8.0%) between t2 and t3. There were significant differences in overall bone density (netavg) between t1 and t3 (p = 0.001; - 3.6%) and between t2 and t3 (p = 0.020; - 2.1%). The data indicate clinically relevant changes of BMD especially in the proximal Gruen zones in the long-term after uncemented THA. Loss of periprosthetic BMD might be a risk factor for periprosthetic fractures.

Effect of bisphosphonates on periprosthetic bone loss after total knee arthroplasty: a meta-analysis of randomized controlled trials

BackgroundAseptic loosening and osteolysis are the most common indications after TKA for revision surgery. This meta-analysis which included high-quality randomized controlled trials (RCTs) aimed to analyze the effect of bisphosphonates (BPs) on maintaining periprosthetic bone mineral density (BMD) after total knee arthroplasty.MethodsPubMed, AMED, EMBASE, the Cochrane library, ISI Web of Science, and China National Knowledge Infrastructure were systematically searched, five RCTs were included and the total number of participants was 188. The weighted mean differences with 95% confidence interval were calculated to evaluate the efficacy of BPs on total BMD of knee and the BMD of different periprosthetic regions. A descriptive review was performed for BP-related adverse effects.ResultsThe BPs group presented significantly higher total BMD in proximal part of the tibia than the control group at 3 and 6 months (P < 0.05), but no significant difference at 12 months (P = 0.09). The BPs group presented significantly higher BMD in the distal aspect of the femur than that in the control group at 3, 6, 12 months. The BPs group presented significantly higher periprosthetic BMD than that in the control group at 3, 6 and 12 months in tibial medial and lateral metaphyseal region, and femoral anterior, central and posterior metaphyseal region (p < 0.05), but no significant difference for tibial diaphyseal region at 3, 6, and 12 months. None of the included studies described severe or fatal adverse effects related to BPs.ConclusionBPs have a short-term effect on reducing periprosthetic bone loss after total knee arthroplasty. Compared with diaphyseal region, BPs are more effective on the preservation of BMD in medial lateral metaphyseal regions of proximal tibia and in anterior, central, and posterior metaphyseal region of distal femur.

A Prospective Assessment of Periprosthetic Bone Mineral Density and Osteoimmunological Biomarkers Variations After Total Knee Replacement Surgery

Aseptic loosening is a major cause of premature failure of total knee replacement (TKR). Variations in periprosthetic bone mineral density (BMD) and osteoimmunological biomarkers levels could help to quantify prosthesis osteointegration and predict early aseptic loosening. The gene expression of 5 selected osteoimmunological biomarkers was evaluated in tibial plateau bone biopsies by real-time polymerase chain reaction and changes in their serum levels after TKR were prospectively evaluated with enzyme-linked immunosorbent assay for 1 yr after surgery. These variations were correlated to changes in periprosthetic BMD. Sixteen patients were evaluated. A statistically significant decrease in serum levels of Sclerostin (p = 0.0135) was observed immediately after surgery. A specular pattern was observed between dickkopf-related protein 1 and osteoprotegerin expression. No statistically significant changes were detectable in the other study biomarkers. Periprosthetic BMD did not change significantly across the duration of the follow-up. Prosthetic knee surgery has an impact on bone remodeling, in particular on sclerostin expression. Although not showing statistically significant changes, in the patterns of dickkopf-related protein 1, osteoprotegerin, and the ligand of the receptor activator of nuclear factor kappa-B symmetries and correspondences related to the biological activities of these proteins could be identified. Variation in osteoimmunological biomarkers after TKR surgery can help in quantifying prosthesis osteointegration.

Restoration of proximal periprosthetic bone loss by denosumab in cementless total hip arthroplasty.

Although bone quality is an important issue in elderly osteoporotic patients who underwent total hip arthroplasty (THA) with a cementless stem, periprosthetic bone mineral density (BMD) in the proximal femur has been reported to be decreased by 15-40% postoperatively. Some authors have examined the use of several types of bisphosphonates to prevent decreases in BMD in the proximal femur after cementless THA; however, few reports have demonstrated success in restoring BMD in the proximal medial femoral bone, such as zone 7. We conducted prospective study comparing patients who underwent cementless THA administered with denosumab (10 patients) and without denosumab (10 patients). BMD around the femoral stem were measured using a DEXA immediately after surgery, and at 6months and at 1year after surgery. No difference was found between the two groups referred to the patient's demographic data. We found that denosumab displayed definitive effects in increasing the % change in periprosthetic BMD at zone 7 by an average of 7.3% in patients with cementless THA, compared to control group who were given only vitamin D. Denosumab is one of a number of anti-osteoporotic agents to have a definitive effect on the restoration of proximal periprosthetic bone loss, especially in zone 7, after cementless THA. Denosumab contributed to the restoration of decreased periprosthetic BMD to normal levels. As the decrease in BMD in the proximal femur after THA is considered to be apparent at 6-12months after surgery, it is believed that prevention of the deterioration of bone quality is important in the proximal femur immediately after cementless THA for elderly female patients with osteoporosis.

An evaluation of proximal femur bone density in young, active patients undergoing total hip arthroplasty at one year postoperatively.

Background:Prior investigations have shown a decrease in periprosthetic bone mineral density (BMD) of the calcar following total hip arthroplasty (THA). The purpose of this investigation was to study proximal femur BMD in a cohort of young, active patients following THA at 1 year postoperatively using a recently introduced stem design.Methods:This was a prospective, IRB-approved investigation of patients with an age <65 years, BMI <35 kg/m2, and presymptomatic UCLA score of >6 undergoing a primary THA for a diagnosis of osteoarthritis. All patients received a titanium, proximally coated, tapered cementless femoral stem (ACCOLADE II, Stryker Inc, Mahwah, NJ, USA). Dual energy X-ray absorptiometry scans were performed at 6 weeks, 6 months, and 1 year postoperatively. Bone density was analyzed for 7 traditional Gruen zones with BMD ratios calculated for change in BMD compared with the baseline.Results:31 patients (mean age of 52.6 + 6.5 years, BMI of 27.9 + 3.9 kg/m2, and UCLA activity score of 7.3 + 1.9) were included. The mean BMD ratio decreased at the 6 months and 1 year interval in zones 1 and 2. However, the mean BMD ratio was maintained in Gruen zones 3 thru 7 with zone 7 (medial calcar) demonstrating 100% maintenance of the baseline BMD at 1 year.Conclusion:This study demonstrates the maintenance of medial calcar bone density at 1 year postoperatively in young, active patients undergoing THA. Further longitudinal analysis of this stem design is necessary to elucidate the significance of this finding.

A long-lasting bisphosphonate partially protects periprosthetic bone, but does not enhance initial stability of uncemented femoral stems: A randomized placebo-controlled trial of women undergoing total hip arthroplasty

Low bone quality may compromise the success of cementless total hip arthroplasty in high-risk patients such as elderly women. Zoledronic acid is a long-lasting antiresorptive agent, which is known to reduce short-term periprosthetic bone loss. However, its effect on femoral stem stability is not well known. Forty-nine female patients with a mean age of 68 years (range, 51–85 years) scheduled to undergo cementless total hip arthroplasty due to osteoarthritis were randomized in this double-blind, placebo-controlled trial to receive a single postoperative infusion of zoledronic acid or placebo. Patients were evaluated for up to four years postoperatively for femoral stem migration measured by radiostereometric analysis, bone mineral density (BMD) measured by dual X-ray absorptiometry, functional recovery, and patient-reported outcome scores. Implant survival was determined at nine years postoperatively. Zoledronic acid did not reduce the femoral stem migration that occurred predominantly during the settling period of the first 3–6 months. Subsequently, all femoral stems were radiographically osseointegrated. Zoledronic acid maintained periprosthetic BMD, while the expected loss of periprosthetic bone during the first 12 months was found in controls. Thereafter, periprosthetic BMD of Gruen zone 7 decreased even in the zoledronic acid group but remained 14.6% higher than that in the placebo group at four years postoperatively. Functional recovery was comparable across the groups. At nine years postoperatively, no revision arthroplasty had been performed. In conclusion, in women at high-risk for low BMD, zoledronic acid had a long-lasting, partially protective effect on periprosthetic bone loss, but the treatment did not enhance the initial femoral stem stability.

The efficiency of risedronate in reducing bone resorption after total hip arthroplasty: a meta-analysis of randomized control trials at a minimum of 6\xa0months\u2019 follow-up

BackgroundRecently risedronate is suggested to be effective for the prevention and treatment of for osteoporosis in total hip arthroplasty. This meta-analysis aimes to evaluate the efficacy of risedronate in reducing femoral periprosthetic bone mineral density loss in patients undergoing primary total hip arthroplasty.MethodsA systematic search was performed in Medline (1966-31 October 2017), PubMed (1966-31 October 2017), Embase (1980-31 October 2017), ScienceDirect (1985-31 October 2017) and the Cochrane Library. Only randomized controlled trial (RCT) were included. Fixed/random effect model was used according to the heterogeneity tested by I2 statistic. Meta-analysis was performed using Stata 11.0 software. The outcome measures included periprosthetic bone mineral density, length of stay and adverse effects.ResultsFour RCTs including 198 patients met the inclusion criteria. The present meta-analysis showed that there were significant differences between treatment groups in terms of periprosthetic bone mineral density in Gruen zones 1 (standard mean difference (SMD) = 0.758, 95% CI 0.469 to 1.047, P = 0.000), 2 (SMD = 0.814, 95% CI 0.523 to 1.106, P = 0.000), 3 (SMD = 0.340, 95% CI 0.059 to 0.622, P = 0.018), 6 (SMD = 2.400, 95% CI 2.029 to 2.771, P = 0.000), and 7 (SMD = 2.400, 95% CI 2.029 to 2.771, P = 0.000).ConclusionOral risedronate could significantly reduce periprosthetic bone resorption around an uncemented femoral stem (Gruen zones 1, 2, 3, 6, and 7) up to 6 months after THA. In addition, no severe adverse events were identified. Future trials of risedronate treatment after THA should focus on clinically relevant end points such as the risks of fracture and revision arthroplasty.

Bisphosphonates for the preservation of periprosthetic bone mineral density after total joint arthroplasty: a meta-analysis of 25 randomized controlled trials.

Periprosthetic bone loss is believed to cause aseptic loosening and failed prosthetic fixation in joint arthroplasty. This meta-analysis which included high-quality randomized controlled trials aimed to analyze the effect of bisphosphonates on maintaining periprosthetic bone mineral density after total joint arthroplasty. Twenty-five RCTs were included and the total number of participants was 1163 by computerized searches of bibliographic databases. The weighted mean differences with 95% confidence interval were calculated to evaluate the efficacy of BPs on total periprosthetic BMD and the BMD of different Gruen zones. Subgroup analyses identified the potentially influencing factors such as surgical site, cement fixation, and generation of BPs. A descriptive review was conducted for BP-related adverse effects. The BPs group presented significantly higher total periprosthetic BMD in the BPs group than that in the control group at 3, 6, 12months, 2-4years, and 5-10years after arthroplasty (P < 0.05). The BPs group presented significantly higher periprosthetic BMD in femoral Gruen Zone 1 and 7 than that in the control group at 3, 6, 12months, 2-4years, and 5-10years (P < 0.05). The heterogeneity was minimized by dividing THA and TKA into two subgroups. Subgroup analyses revealed that the effect of BPs on preservation of BMD was significantly greater in arthroplasty with cemented component than in that with uncemented component at 12months and 5-10years (P < 0.05), and the administration of the second and third generation BPs was significantly more effective than the first-generation BPs at 6 and 12months (P < 0.05). None of the included studies described severe or fatal adverse effects related to BPs. BPs have significantly long-term efficacy on the preservation of periprosthetic BMD after joint arthroplasty. To obtain a better efficacy, the cemented components and the second and third generation BPs are recommended.

Effect of risedronate on femoral periprosthetic bone loss following total hip replacement: A systematic review and meta-analysis.

Background:Recent study has reported that risedronate was effective in reducing periprosthesis bone loss after total hip arthroplasty (THA). The meta-analysis was performed to compare the clinical outcomes of THA with oral risedronate versus placebo.Methods:Electronic databases: PubMed (1950–March 2018), EMBASE (1974–March 2018), the Cochrane Central Register of Controlled Trials, Web of Science (1950–March 2018) were systematically searched. Two authors independently graded the methodological quality of each eligible study using the Cochrane Collaboration tool and extracted relevant data. Statistical heterogeneity among the trials were evaluated with chi-square and I-square tests. This meta-analysis was performed using STATA 14.0.Results:A total of 4 randomized controlled trials (RCTs) published between 2006 and 2015 were included in our study. The meta-analysis demonstrated that risedronate was associated with a significantly reduction of periprosthetic bone mineral density after THA. No increased postoperative complications were observed.Conclusion:Oral risedronate might reduce the periprosthetic bone resorption after cementless THA. Additionally, no severe adverse effects were observed. High-quality RCTs with large sample size were still required.

Periprosthetic bone remodelling of short-stem total hip arthroplasty: a systematic review.

Short-stem hip arthroplasty (SHA) was designed to preserve bone stock and provide an improved load transfer. To gain more evidence regarding the load transfer, this review analysed the periprosthetic bone remodelling of SHA in comparison to standard hip arthroplasty (THA). PubMed and ScienceDirect were screened to extract dual-energy X-ray absorptiometry (DXA) studies evaluating the periprosthetic bone remodelling of SHA and two proven THA designs. From the studies included, the postoperative change in periprosthetic bone mineral density (BMD) after one year and the trend over two years was determined. Fifteen studies with four SHAs (CFP, Metha, Nanos, Fitmore) and two THAs (CLS and Bicontact) designs were included. All SHA and THA stems revealed an initial decrease at the calcar and major trochanter (Gruen 1 and 7) with the Metha, Nanos and Fitmore showing a smaller and more balanced remodelling compared to THA. The pattern after one year and the trend over two years argue for a methaphyseal anchorage of the Metha and Nanos, whereas the Fitmore and CFP seem to anchor metha-diaphyseal. Clearly different pattern of bone remodelling were observed between all four SHAs. Periprosthetic bone remodelling is also present in SHA, with the main bone reduction observed proximally. However, certain SHA stems show a more balanced remodelling compared to THA, arguing for a favourable load transfer. Also, the femoral length where bone remodelling occurs is clearly shorter in SHA. As distinctively different pattern between the SHA designs were observed, they should not be judged as a single implant group.

Less periprosthetic bone loss following the anterolateral approach to the hip compared with the direct lateral approach

Background and purpose — The loss of bone mineral in the proximal femur following hip arthroplasty may increase the fracture risk around uncemented stems. We hypothesized that the surgical approach to the hip might influence bone mineral changes around the femoral stem in patients with a femoral neck fracture (FNF).Patients and methods — This was a pre-specified subgroup analysis (n = 51) of an ongoing randomized trial (n = 120) in patients with FNF. Participants were allocated to an uncemented hemiarthroplasty inserted through a direct lateral (Hardinge) approach or an anterolateral (modified Watson-Jones) approach. The 51 patients (mean age 83 (70–90) years, 33 women) were measured by dual-energy X-ray absorptiometry (DXA) to assess changes in periprosthetic bone mineral density (BMD).Results — The mean change in total BMD differed between groups at 12 months in favor of the anterolateral group (4.8%, 95% CI 0.0–9.6; p = 0.05). DXA at 3 months displayed BMD loss in the proximal Gruen zones in the lateral group compared with the anterolateral group. Zone 1 (–5.0% vs. 2.7%), zone 2 (–4.3% vs. 4.1%), zone 6 (–6.5% vs. 0.0%) and zone 7 (–11% vs. –2.4%, all p < 0.05).Interpretation — DXA measurements in this study indicate that surgical approach to the hip influences periprosthetic BMD. Clinical implications remain uncertain. Our conclusions should be interpreted with caution as we did not perform adjustments for multiple tests, possibly leading to inflation of false-positive findings.

Stem anteversion mismatch to the anatomical anteversion causes loss of periprosthetic bone density after THA.

The short tapered-wedge stem is popular worldwide because it potentially preserves more bone stock during total hip arthroplasty (THA). However, stem version mismatch may affect physiological stress distribution. In this study, we analyzed the correlations between periprosthetic bone mineral density (BMD) changes and anteversion mismatch in patients who underwent THA using a short tapered-wedge stem. The study included 44 patients (44 joints) who underwent THA with a Tri-Lock stem. At baseline and at 6 and 24 months postoperatively, the BMDs in the seven Gruen zones were evaluated using dual-energy X-ray absorptiometry. BMD changes and stem alignment, that is, anteversion and stem anteversion mismatch to the anatomical canal anteversion, were analyzed. Significant negative correlations were found between BMD changes and absolute anteversion error in Gruen zones 1 and 7 at 6 and 24 months postoperatively (zone 1, 6M; RR= -0.48, p < 0.001) (zone 7, 6M; RR= -0.46, p = 0.002) (zone 1, 24M; RR= -0.47, p = 0.001) (zone 7, 24M; RR= -0.40, p = 0.007). We further demonstrated that excessive stem anteversion mismatch to the anatomical canal anteversion causes stem point contact with the cortical bone in the distal portion and affected proximal periprosthetic BMD loss after THA. We recommend that the native anatomical anteversion angle should be used as a reference for inserting the tapered-wedge stems.

Teriparatide Administration Increases Periprosthetic Bone Mineral Density After Total Knee Arthroplasty: A Prospective Study

BackgroundTeriparatide is a currently available therapeutic agent for osteoporosis. Previous studies have reported that teriparatide affects periprosthetic bone mineral density (BMD) after total knee arthroplasty (TKA). However, little agreement has been reached concerning the treatment of periprosthetic BMD after TKA with teriparatide. Moreover, BMD in the femoral and tibial sides of the joints together has never been examined. We investigated the efficacy of teriparatide to inhibit BMD loss in the femoral and tibial side and considered complications such as migration and periprosthetic fractures after TKA. MethodsTwenty-two knees in 17 patients were included in this study, and a control group of patients who underwent TKA was identified according to their medical records. Dual-energy X-ray absorptiometry was performed for different locations (knee, hip, and lumbar spine), and regions of interest were measured to estimate BMD at initiation of the study as a baseline reference, followed by subsequent measurements at 6 and 12 months. ResultsAs a result of adjusting the difference between the BMDs of the 2 groups at initiation, there was a significant increase in R3 (posterior condyle) and R4 (lateral) at 6 months. Furthermore, there was a significant increase in R2 (anterior condyle), R3 (posterior condyle), and R6 (tibial diaphysis) at 12 months. The study group had a higher adjusted mean BMD in all regions than did the control group at 6 and 12 months. ConclusionTeriparatide may be a reasonable treatment option for osteoporotic patients to preserve or improve periprosthetic BMD after TKA.

The effect of simvastatin on periprosthetic bone mineral density in the hypercholesterolaemic patients after total hip arthroplasty.

The purpose of this study was to investigate the effect of simvastatin on periprosthetic bone mineral density (BMD) in hypercholesterolaemic patients after total hip arthroplasty. From January 2012 to December 2015, a total of 42 consecutive hypercholesterolaemic patients with total hip arthroplasty were recruited for this study. The simvastatin group was 21 patients (15 males, 6 females) with average age of 69.4±6.6years treated with simvastatin for one year post-operatively, and the control group was the other 21 patients (12 males, 9 females) who did not take simvastatin. These parameters of the periprosthetic bone mineral density after total hip arthroplasty were collected by dual energy X-ray absorptiometry(DEXA) one week and three, six, 12 months post-operatively. In the control group patients showed significant loss of periprosthetic BMD in ROIs 1, 2, 6, and 7 throughout the study period. The loss of BMD in ROIs 3 and 5 was only significantly observed at three months follow-up and recovered thereafter. There were no significant detected changes of BMD in ROI 4. In the Simvastatin group, the percentage of BMD loss was significantly less (P<0.05) in ROI 1, 2, 6 and 7 throughout the study period than the control group. The percentage of BMD loss were significant observed in ROI 3 and 5 at three months follow-up, which were also significantly less (P<0.05) than in the control group. A slight gain of BMD was measured in ROI 4 at 12months follow-up (1.419%, P<0.05). Simvastatin administered for one year post-operatively can effectively prevent periprosthetic bone loss after total hip arthroplasty.

Quantifying Pelvic Periprosthetic Bone Remodeling Using Dual-Energy X-Ray Absorptiometry Region-Free Analysis

The gold standard tool for measuring periprosthetic bone mineral density (BMD) is dual-energy X-ray absorptiometry (DXA). However, resolution of the method is limited due to the aggregation of pixel data into large regions of interest for clinical and statistical analysis. We have previously validated a region-free analysis method (DXA-RFA) for quantitating BMD change at the pixel level around femoral prostheses. Here, we applied the DXA-RFA method to the pelvis, and quantitated its precision in this setting using repeated DXA scans taken on the same day after repositioning in 29 patients after total hip arthroplasty. Scans were semiautomatically segmented using edge detection, intensity thresholding, and morphologic operations, and elastically registered to a common template generated through generalized Procrustes analysis. Pixel-wise BMD precision between repeated scans was expressed as a coefficient of variation %. Longitudinal BMD change was assessed in an independent group of 24 patients followed up for 260 wk. DXA-RFA spatial resolution of 0.31 mm2 provided approximately 12,500 data points per scan. The median data-point precision was 17.8% (interquartile range 14.3%–22.7%). The anatomic distribution of the precision errors showed poorer precision at the bone borders and superior precision to the obturator foramen. Evaluation of longitudinal BMD showed focal BMD change at 260 wk of −26.8% adjacent to the prosthesis-bone interface (1% of bone map area). In contrast, BMD change of +39.0% was observed at the outer aspect of the ischium (3% of bone map area). Pelvic DXA-RFA is less precise than conventional DXA analysis. However, it is sensitive for detecting local BMD change events in groups of patients, and provides a novel tool for quantitating local bone mass after joint replacement. Using this method, we were able to resolve BMD change over small areas adjacent to the implant-bone interface and in the ischial region over 260 wk after total hip arthroplasty.

Equal Primary Fixation of Resurfacing Stem, but Inferior Cup Fixation With Anterolateral vs Posterior Surgical Approach. A 2-Year Blinded Randomized Radiostereometric and Dual-energy X-Ray Absorptiometry Study of Metal-on-Metal Hip Resurfacing Arthroplasty

BackgroundThe anterolateral (AntLat) surgical approach may spare the blood supply to the femoral head and improve the accuracy of cup positioning in metal-on-metal hip resurfacing arthroplasty. Thereby, potentially lessen complications such as avascular head necrosis, femoral neck narrowing and fracture, improve implant fixation, and lessen periprosthetic bone mineral density (BMD) loss. MethodsBetween November 2008 and January 2012, a randomized clinical trial was performed at Aarhus University Hospital. A total of 49 patients (28 males) were allocated to metal-on-metal hip resurfacing arthroplasty by the AntLat (n = 25) or the posterior (Post; n = 24) surgical approach. Patients were followed with radiostereometric analysis, measurements of periprosthetic BMD, clinical outcome scores of Harris hip score and visual analogue scale, serum metal ions, and conventional radiographs. ResultsAt 3 months, cups in the AntLat group had higher total translations of mean 1.00 ± 0.70 mm vs mean 0.64 ± 0.45 mm in the post group (P = .04), and higher total rotations of mean 2.44° ± 1.36° vs mean 1.39° ± 1.17° in the Post group (P = .002). All migrations of cup and stem were similar at 1 and 2 years postoperative (P > .07). At 1 year, periprosthetic BMD since postoperative at the medial side of the stem was reduced to mean 98.45% ± 8.57% in the AntLat group, and increased to mean 105.57% ± 11.07% in the Post group (P = .02), but measurements were comparable at 2 years (P = .05). ConclusionCups inserted by the AntLat approach migrated more until 3 months postoperative. This illustrates a less good primary cup fixation with the AntLat approach; however, all cups were well-fixed after 3 months' follow-up indicating a good secondary fixation.