Purpose. The purpose of this study was to evaluate periprosthetic bone mineral density (BMD) changes around a cementless short tapered-wedge stem and determine correlations between BMD changes and various clinical factors, including daily activity, after total hip arthroplasty (THA) with a short tapered-wedge stem. Methods. The study included 65 patients (65 joints) who underwent THA with a TriLock stem. At baseline, and 6, 12, and 24 months postoperatively, BMDs of the seven Gruen zones were evaluated using dual-energy X-ray absorptiometry. Correlations were determined between BMD changes and clinical factors, including the Harris hip score, body mass index, University of California at Los Angeles (UCLA) activity rating score, age at surgery, and initial lumbar BMD. Results. Minimal BMD changes were noted in the distal femur (Gruen zones 3, 4, and 5). However, significant BMD loss was noted in zone 7 at each time point. BMD loss was also noted in zone 1 at 6 and 12 months postoperatively, but BMD recovered after 18 months. Significant positive correlations were noted between BMD changes and the UCLA activity rating score in zones 1, 6, and 7. Additionally, negative correlations were noted between BMD changes and initial spine BMD in zones 2 and 3. Table legends. Table 1 Background of the patients. Table 2 Bone mineral density changes (%) at 6, 12, and 24 months postoperatively in the seven Gruen zones. Columns represent mean ± standard deviation. ※indicates P < 0.05 compared with baseline bone mineral density. Table 3 Correlations between periprosthetic bone mineral density changes and clinical factors (the Harris hip score, body mass index, University of California at Los Angeles activity rating score, age at surgery, and initial lumbar bone mineral density) in the seven Gruen zones at 24 months postoperatively. Correlation coefficients and P-values are presented. Boldface indicates P < 0.05. Conclusion. Periprosthetic BMD was maintained in the proximal femur, especially Gruen zone 1, with a short tapered stem. Daily activity may reflect improvements in periprosthetic bone quality after THA with a short tapered stem; however, this stem is not recommended in patients with low bone quality. To view tables, please contact authors directly

Introduction. Several short femoral stems have been introduced in primary total hip arthroplasty, supposedly in order to save proximal bone stock. We intended to analyse primary stability, changes in periprosthetic bone mineral density (BMD), and clinical outcome after insertion of the uncemented collum femoris preserving (CFP)-femoral device. Methods. A prospective cohort study on 30 patients scheduled for receiving the CFP-stem combined with an uncemented cup was carried out. Stem migration was analysed by radiostereometry (RSA). Preoperative total hip BMD and postoperative periprosthetic BMD in Gruen zones 1–7 was investigated by DXA, and the Harris hips score (HHS) was determined. The patients were followed up to 12 months. Results. 2 patients were intraoperatively excluded because their proximal femur was found to be unsuitable for insertion of the studied implant, 1 patient was later revised due to a deep infection. This left 27 patients for final analysis. RSA showed that only very little migration of the implant occurred, with the largest amplitude found in rotation around the y-axis (1.8°, SD 0.6, after 12 mths), representing minimal stem retroversion. DXA after 12 mths demonstrated substantial BMD loss in Gruen zones 7 (−30.8%), 6 (−19.1%) and 2 (−13.3%, p-values for all described changes <0.001 when comparing with baseline BMD determined immediately postoperatively). There was a moderate correlation of low preoperative total hip BMD with a higher amount of bone loss in Gruen zones 2 (Pearson correlation coefficient r = 0.6, p = 0.001), 6 (r = 0.5, p = 0.005) and 7 (r = 0.6, p = 0.003). In contrast, we found no correlation of periprosthetic bone loss in any of the Gruen zones 1–7 with logarithmically transformed maximal total point translation (MTPT) of the stem (p > 0.05 for all regions), neither after 3 nor after 12 mths. The mean HHS increased from 49 (SD 15) preoperatively to 99 (SD 2) after 12 mths. Interpretation. Based on these short-term data, we conclude that i) the studied implant seems to be stable within the first year, ii) substantial loss in periprosthetic BMD - with a predominance in the calcar region - occurs, iii) low preoperative total hip BMD predisposes towards greater loss of periprosthetic BMD after 12 months, iv) postoperative loss in periprosthetic BMD does not correlate with increased stem migration. Clinical results are excellent so far. Continuing follow-up will reveal whether this novel stem remains stable in the medium and long term, and whether the loss in BMD in the regions mentioned above can be recovered with time or whether it continues

Dual energy X-ray absorptiometry (DXA) is a precise tool for measuring bone mineral density (BMD) around total joint prostheses. The Hologic ‘metal-removal hip’ analysis package (Hologic Inc, Waltham, Massachusetts) is a DOS-based analysis platform that has been previously validated for measurement of pelvic and proximal BMD after total hip arthroplasty (THA). This software has undergone a change in the operating platform to a Windows-based system that has also incorporated changes to DXA image manipulation on-screen. These changes may affect the magnitude of random error (precision) and systematic error (bias) when compared with measurements made using the previously validated DOS-based system. These factors could influence interpretation of longitudinal studies commenced using the DOS system and later completed using the Windows system. The aims of this study were to compare the precision and bias of pelvic and femoral periprosthetic BMD measurements made using the Windows versus the DOS analysis platform of the Hologic ‘metal-removal hip’ software. A total of 29 subjects (17 men and 12 women) with a mean age of 51years (SD±10), who had undergone hybrid THA using a cemented stem and uncemented cup. Subjects underwent duplicate DXA scans of the hemipelvis and proximal femur taken on the same day after a period for repositioning.. Scans were obtained with the patient lying supine in the scanner with the legs in extension and the foot in a neutral position. Scans were carried out using the same Hologic QDR 4500-A fan-beam densitometer in ‘metal-removal hip’ scanning mode. The DXA scan acquisitions were analysed using both the DOS and the Windows versions of the analysis software. The same observer made all analyses (NRS). Pelvic scans were analysed using a four region of interest model and femoral scans were analysed using a seven region of interest model. Precision was expressed as coefficient of variation (CV%) and compared between methods using the F-test. Systematic bias was examined using the Bland and Altman method and paired t-test. The CV% for the pelvic regions of interest (n=4) varied from 3.92 to 8.54 and from 2.36 to 5.96 for the Windows and DOS systems, respectively. The CV% for the net pelvic region was 3.04 and 2.36 for Windows versus DOS, respectively (F- test, p> 0.05). The CV% for the femoral regions of interest (n=7) varied from 1.58 to 4.14 and from 1.84 to 4.65 for the Windows and DOS systems, respectively. The CV% for the net femoral region was 1.75 and 1.51 for Windows versus DOS, respectively (F- test, p> 0.05). Absolute BMD values for the net pelvic region were similar (Bland-Altman, Windows minus DOS value mean = -1.0%, 95% CI −7.5 to 5.6; t-test p.0.05). Absolute BMD values for the net femoral region were also similar (Bland-Altman, Windows minus DOS value mean = 1.3%, 95% CI −8.3 to 10.8; t-test p.0.05). In summary precision of the measurements using the 2 operating systems was similar and there was no systematic bias between methods. These data suggest that scans analysed using each platform may be used interchangeably within the same study subjects, without the need of a calibration correction.

Femoral stem design affects periprosthetic bone mineral density (BMD), which may impact long term survival of cementless implants in total hip arthroplasty (THA). The aim of this study was to examine proximal femoral BMD in three morphologically different uncemented femoral stems designs to investigate whether one particular design resulted in improved preservation of BMD. 119 patients were randomized to receive either a proximally coated dual taper wedge stem, a proximally coated anatomic stem or a fully coated collarless triple tapered stem. Dual energy x-ray absorptiometry scans (Lunar iDXA, GE Healthcare, Madison, WI) assessed BMD across the seven Gruen zones pre-operatively, and post-operatively at 6-weeks, 1-year, and 2-years comparing the unoperated contralateral femur as a control. BMD increased in zones one (2.5%), two (17.1%), three (13.0%), five (10%) and six (17.9%) for all stems. Greater preservation of BMD was measured on the lateral cortex (zone 2) for both the dual taper wedge and anatomic stems (p = 0.019). The dual taper wedge stem also demonstrated preservation of BMD in the medial calcar (zone 7) whilst the anatomic and triple taper stem declined in this region, however this was not statistically significant (p = 0.059). BMD decreased on average by 2.1% in the mid-diaphysis region, distal to the stem tip (zone 4) for all implants. All stems performed equivalently at final follow-up in all patient reported outcome measures. Implant design was shown to impact BMD changes. All stems preserved bone at the metaphyseal level in early follow-up, which theoretically indicates favorable implant fixation. There was no significant stress shielding observed, however longer follow-up is required to elucidate the impact of this finding on implant survivorship

Femoral stem design affects periprosthetic bone mineral density (BMD), which may impact long term survival of cementless implants in total hip arthroplasty (THA). The aim of this study was to examine proximal femoral BMD in three morphologically different uncemented femoral stems designs to investigate whether one particular design resulted in improved preservation of BMDMethods: 119 patients were randomised to receive either a proximally coated dual taper wedge stem, a proximally coated anatomic stem or a fully coated collarless triple tapered stem. All surgeries were performed via the posterior approach with mobilization on the day of surgery. Dual energy x-ray absorptiometry scans (Lunar iDXA, GE Healthcare, Madison, WI) assessed BMD across the seven Gruen zones pre-operatively, and post-operatively at 6-weeks, 1-year, and 2-years and compared to the unoperated contralateral femur as a control. Patient reported outcome measures of pain, function and health were also included at these corresponding follow-ups. BMD increased in zones one (2.5%), two (17.1%), three (13.0%), five (10%) and six (17.9%) for all stems. Greater preservation of BMD was measured on the lateral cortex (zone 2) for both the dual taper wedge and anatomic stems (p = 0.019). The dual taper wedge stem also demonstrated preservation of BMD in the medial calcar (zone 7) whilst the anatomic and triple taper stem declined in this region, however this was not statistically significant (p = 0.059). BMD decreased on average by 2.1% inthe mid-diaphysis region, distal to the stem tip (zone 4) for all implants. All stems performed equivalently at final follow-up in all patient reported outcome measures. This study demonstrated maintenance of femoral BMD in three different cementless femoral stem designs, with all achieving excellent improvements in patient reported outcomes. There was no significant stress shielding observed, however longer follow-up is required to elucidate the impact of this finding on implant survivorship

Aim: Stress-shielding is a common problem after uncemented THA that may lead to proximal femoral atrophy and consecutive aseptic loosening. Methods: In 143 patients with 154 uncemented CLS-stems periprosthetic bone mineral density (BMD) was measured using DXA after a mean of 12 years (10–15) postoperatively (T1). Five years later the same group of patients was examined at a mean of 17 years (range: 15–20) (T2) using the identical protocol. Results: We obtained a complete prospective set of data of two consecutive DXA measurements in 76 cases (32 men, 44 women). In all cases regular bone ongrowth did occur and there were no signs of radiographic loosening (T1 and T2). On radiographic evaluation there was no significant change in periprosthetic bone formation in all Gruen zones between T1 and T2. There was no significant change in activity and BMD. In male patients we found no significant changes in periprosthetic BMD (netavg T1–T2: −1,19%, p< 0,01), in female patients there was no significant difference either (netavg T1–T2: −1,32%,p< 0,01). We analyzed the differences in BMD in all Gruen zones (zone 1–7) comparing T1 and T2 and found no significant differences in any zone (p< 0,01). Conclusion: This study showed that there is no significant change in periprosthetic bone mineral density in the long term using the uncemented CLS stem. There was not a single case of stress shielding in the long term. Once osseous integration has occurred the periprostethic BMD changes remain minimal in the long term

Introduction and Aims: Periprosthetic bone loss is responsible for the majority of cases of implant failure after total joint arthroplasty. Bisphosphonates are effective in reducing bone loss in many conditions associated with accelerated bone turnover. Our aim was to determine the effect of bisphosphonates on periprosthetic bone mineral density (BMD, g/cm2) after total joint arthroplasty. Method: We conducted computerised searches for randomised controlled trials, evaluating the effects of bisphosphonates on periprosthetic bone mineral density in patients undergoing primary total joint arthroplasty. We searched MEDLINE, EMBASE, CINAHL, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews and the United Kingdom National Research Register Web-site to November 2003. Computerised searches of the archives of AAOS Annual Meetings 1989–2003 were also conducted. Additional strategies to identify articles included a hand search of the bibliographies of relevant articles and direct contact with the authors. Results: Of 386 citations initially identified, nine citations met our eligibility criteria. The total number of randomised controlled trials was six (five published and one abstract). Four trials evaluated total hip arthroplasty and two examined total knee arthroplasty. Five trials used alendronate and one used pamidronate. Quality scores ranged from 65 to 75. The pooled sample size was 290 patients. Less periprosthetic bone loss occurred in the intervention group compared to the control group at the following follow-up intervals: three months (n=128, Weighted Mean Difference (WMD): 3.3%, 95% Confidence Interval (CI): 1.9–4.7, p< 0.01); six months (n=224, WMD: 4.5%, CI: 1.6–7.4, p< 0.001); and 12 months (n=173, WMD: 4.2%, CI: 1.5–6.9, p=0.03). Tests of heterogeneity revealed greater maintenance of BMD in cemented arthroplasty than in uncemented arthroplasty (WMD: 7.5%, CI: 4.3–10.7 versus WMD: 2.1%, CI: 0.61–3.6, respectively, p< 0.001) at 12 months follow-up. Conclusion: Bisphosphonates have a beneficial effect on maintaining periprosthetic bone stock compared to control after total joint arthroplasty. The effect seems greater in cemented arthroplasty and total knee arthroplasty. Whether this increase in BMD results in improved fixation and longevity of prosthetic components remains unanswered. Larger trials evaluating the effect of bisphosphonates on rates of implant loosening and functional outcomes are needed

Objectives. Our primary aim was to describe migration of the Exeter stem with a 32 mm head on highly crosslinked polyethylene and whether this is influenced by age. Our secondary aims were to assess functional outcome, satisfaction, activity, and bone mineral density (BMD) according to age. Patients and Methods. A prospective cohort study was conducted. Patients were recruited into three age groups: less than 65 years (n = 65), 65 to 74 years (n = 68), and 75 years and older (n = 67). There were 200 patients enrolled in the study, of whom 115 were female and 85 were male, with a mean age of 69.9 years (sd 9.5, 42 to 92). They were assessed preoperatively, and at three, 12 and, 24 months postoperatively. Stem migration was assessed using Einzel-Bild-Röntgen-Analyse (EBRA). Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS), Hip Disability and Osteoarthritis Outcome Score (HOOS), EuroQol-5 domains questionnaire (EQ-5D), short form-36 questionnaire (SF-36,) and patient satisfaction were used to assess outcome. The Lower Extremity Activity Scale (LEAS), Timed Up and Go (TUG) test, and activPAL monitor (energy expelled, time lying/standing/walking and step count) were used to assess activity. The BMD was assessed in Gruen and Charnley zones. Results. Mean varus/valgus tilt was -0.77⁰ and axial subsidence was -1.20 mm. No significant difference was observed between age groups (p ⩾ 0.07). There was no difference according to age group for postoperative WOMAC (p ⩾ 0.11), HHS (p ⩾ 0.06), HOOS (p ⩾ 0.46), EQ-5D (p ⩾ 0.38), patient satisfaction (p ⩾ 0.05), or activPAL (p ⩾ 0.06). Patients 75 years and older had a worse SF-36 physical function (p = 0.01) and physical role (p = 0.03), LEAS score (p < 0.001), a shorter TUG (p = 0.01), and a lower BMD in Charnley zone 1 (p = 0.02). Conclusion. Exeter stem migration is within normal limits and is not influenced by age group. Functional outcome, patient satisfaction, activity level, and periprosthetic BMD are similar across all age groups. Cite this article: N. D. Clement, M. Bardgett, K. Merrie, S. Furtado, R. Bowman, D. J. Langton, D. J. Deehan, J. Holland. Cemented Exeter total hip arthroplasty with a 32 mm head on highly crosslinked polyethylene: Does age influence functional outcome, satisfaction, activity, stem migration, and periprosthetic bone mineral density? Bone Joint Res 2019;8:275–287. DOI: 10.1302/2046-3758.86.BJR-2018-0300.R1

Purpose: With appropriate software, dual energy x-ray absorptiometry (DEXA) provides a means of measuring periprosthetic bone mineral density (BMD) reliably and reproducibly in a single plane. The current method has been improved since the first reports by MacCarthy in 1991. Material and methods: Since 1992, two series of total hip arthroplasty femoral prostheses using a ceramic-polyethylene cup with a TA6V4 stem were implanted with cement (group A 25 SAS crystal anatomic stems, 22.2 head) or without cement (group B, 27 Euroform stems with hydroxyapatite surfacing on the upper 2/5, 28 head). The patients were followed prospectively with DEXA to measure BMD in the seven Gruen zones immediately after surgery, at six and twelve months, then every year to last follow-up. Mean follow-up was 74 months (36–166). A visual analogue scale was used for subjective assessment of pain. The clinical Harris score and radiological findings were also recorded. Results: At last follow-up none of the prostheses had required revision surgery. The Harris score was greater than 90 for both groups (mean 91.4 and 95.4 for groups A and B respectively). Radiologically, there were no progressive lucent lines in the two groups but there were three stable lines (zone V, VII, VII, II) without clinical expression in group A and two (zone II, I) with persistent thigh pain in group B. Two migrations of less than 3 mm were also found in group A and four of more than 3 mm in group B. For the two groups, DEXA showed a diffuse reduction in BMD during the first six months that was statistically significant only for zones I and VII for the Euroform implant and for zone VII for the SAS Crystal implant. There was also a significant difference between the two prostheses for zone I. Modifications were not significant at three years and a last follow-up for the distal regions (II, II, V, VI). For group A (SAS Crystal), the reduction was 5.8% at three years and 5.7% at last follow-up for zone I and 18% at three years and 19% at last follow-up for zone VII. For group B, the reduction was 12.6 at three years and 11.4% at last follow-up for zone I and 17.4% at three years and 21.3% at last follow-up for zone VII. Discussion: The correlations showed that variations in BMD were independent of the initial bone mineral content, patient age or sex, and were not significantly different between the two cemented or non-cemented implants. Patients with painful thighs (two in group A and six in group B) had a different pattern of BMD over time, showing less pronounced reduction in the proximal zones I and VII and marked bone resorption in zones III and V, an expression of different stress transmission. Conclusion: This study provided the longest longitudinal radiological and clinical follow-up reported in the literature which, despite the bias introduced by the different types of implants, shows the reliability and reproducibility of DEXA of periprosthetic bone mineral density used to assess implant tolerance and quality of cementing

Cementless total knee replacement (TKR) is at the present date a controversial topic. Aim of the study was to compare the effect on tibial periprosthetic bone mineral density (BMD) between different implant materials and designs. During the two-year period between January 2005 and December 2006, we analysed data of 45 patients who underwent consecutively cementless TKR (49 implants) at our Institution for primary osteoarthritis. Data was divided in 2 groups: A) 26 implants with tantalium tibial component (Zimmer NexGen Trabecular Metal. TM. Monoblock); B) 23 implants with porous titanium tibial component (Lima MultiGen. TM. ). Data was comparable per sex, age, BMI, post-op alignment, post-op KSS > 75, absence of major post-op complications. Standard AP x-rays were taken 4 months post-op and 8 years post-op. In order to quantify the reduction of BDM, we determined using ImageJ (an open source software) the Mean Grey Value (MGV) of a specific area on the 4 months- and 8 yrs-postop AP x-rays. Group A and Group B had an average MGV variation of, respectively, 11.79% and 10.51%; there was no statistically significant difference between the two groups. Reduction of BMD in a TKR is known to be a biomechanical response to load and it is conditioned by the alignment of the components and their design. Our study shows that the different materials (porous titanium vs. tantalium), in relation to the different implant design, have a similar effect on the surrounding bone. The overall results show a valid osseointegration in both group of patients

Purpose. The study aim was to assess how the periprosthetic bone density of the MiniHip™ changed in the course of the first year. Is there a correlation between the decrease in bone density with CCD angle or stem size? Are there other variables influencing the changes in bone density?. Material and Methods. 62 patients aged 25–78 years (34 women, 28 men) were implanted with a MiniHip total hip replacement during 2011 and 2012 through an anterolateral minimally invasive (ALMI) approach. Pre-operative diagnosis was osteoarthritis in 49 patients, dysplasia in 7, femoral necrosis in 4 and femoral neck fracture in 2 cases. As a primary variable the periprosthetic bone mineral density (BMD) was measured postoperatively within the first 2 weeks as a baseline measurement. Follow-up measurements were performed at 3, 6 and 12 months postoperatively. Statistical analysis was conducted to show any differences. Results. There is an initial post-operative loss of BMD in the first 3 months due to surgery and inactivity, with a significant decrease in the periprosthetic BMD proximally in Gruen Zones 1 (10.05%), 2 (12.37%) and 7 (10.05%) and distally in Gruen Zone 4 (6.9%). The density in the remaining Gruen regions also decreased but was not significant. In the following 3 months, the decrease in this Gruen regions continues without being significant. But after 6 months the bone mineral density shows a regeneration. At 12 months compared with the 6 months results there is an increase in BMD in Gruen Zones 1 (5.09%) and 7 (2.82%), also an increase in Gruen Zone 3 (1.75%) and 4 (1.78%) [Fig. 1]. A significant correlation between stem size and proximally bone loss in Gruen zones 1 & 7 was seen. In Gruen zone 1, there is also a correlation between bone loss and femoral neck angle, whereas this correlation was not significant in Gruen zone 7, but showing the same tendency. The analysis of covariables showed no dependencies of the results to sex, diagnosis or bearing surfaces. Conclusion. The MiniHip shows a loss of bone mineral density immediately post-operatively. After the initial decrease there was an increase especially in the proximal Gruen zones 1 and 7. Compared to other cementless short stems there was a lower bone density decrease [Fig. 2]. MiniHip™ loads the proximal femur in a more physiological way, which may preserve more bone in zones 1 and 7

The hypothesis of the current study was that the loading of the proximal femur is altered significantly by the surgical approach. The change in long-term periprosthetic bone mineral density in relation to the alteration of the musculature after the anterolateral (Group A) and transgluteal approaches (Group B) has been compared. Group A comprised 35 hip joints (30 patients) and Group B 47 hip joints (37 patients). No significant differences were seen between groups in respect to age, gender, or diaphyseal BMD distribution and in respect to average stem size in a Wilcoxon test. Measurement of BMD in femoral Gruen Zones I, II, VI, and VII revealed a significant bone loss in Group B compared with Group A; however the functional outcome showed no significant differences between the two groups postoperatively. Analysis of proximal femoral loading by means of a validated musculoskeletal model showed a considerable redistribution of the musculoskeletal loading across the hip during walking and stair climbing after a transgluteal compared with an anterolateral surgical approach. The muscular damage caused by the surgical approach seems to have a significant influence on the long-term bone loss and the initial postoperative loading of the proximal femur

Background: Joint replacements are being performed on ever younger patients at a time when average expectancy of life is continuing to rise. Any reduction in the strength and mass of periprosthetic bone could threaten the longevity of implant by predisposing to loosening and migration of prosthesis, periprosthetic fracture and problems in revision arthroplasty. Aims & Objectives: This study aims to analyse and compare prospectively the femoral periprosthetic stress-shielding around 4/5th and 1/3rd porous coated cementless femoral stems in patients undergoing unilateral cementless total hip replacement done using DEXA scan by quantifying the changes in bone mineral density around femoral component. Material & Method: Femoral periprosthetic bone mineral density was measured in the seven Gruen Zones with DEXA scan at 2 weeks, 1 years and 2 years after surgery in 60 patients who had undergone unilateral cementless total hip replacement, of which 30 patients had been implanted with 4/5th porous coated stems and other 30 patients with 1/3rd porous coated stems. Results: At both one and two years postoperatively, bone loss due to stress-shielding was seen in both stems with maximum loss in zone VII and minimum in zone III, IV, V. The maximum mean percentage bone mineral density loss in 4/5th porous coated stems in zone VII was 16.03% at one year and 22.42% at 2 years as compared to loss of 10.07% and 16.01% in 1/3rd porous coated stems. Increased bone loss was seen in patients who had larger diameter stem (> 13.0 mm) and in patients with low bone mineral density in the unoperated hip. Conclusion: Bone loss as a result of stress-shielding is more pronounced in 4/5. th. porous coated stems as compared to 1/3. rd. porous coated stems

An acute phase of periprosthetic bone loss occurs following total hip arthroplasty (THA). Periprosthetic bone loss undermines implant support, may contribute to its failure, and complicates revision surgery as allograft may be required to replace lost bone. We assessed the effect of a single 90mg dose of the bisphosphonate pamidronate on early periprosthetic bone mineral density (BMD), biochemical markers of bone turnover, and clinical outcome in 47 men and women undergoing hybrid THA in a randomised, double-blinded, placebo-controlled trial. The mean (± 95% CI) differences in BMD (area under BMD change.time curve) between those receiving pamidronate and those receiving placebo was 0.91(± 0.51) g.weeks/cm. 2. for the proximal femur (P=0.002), and 0.80 (±0.60) g.weeks/cm. 2. for the pelvis (P=0.009). Patients in the pamidronate group had suppression of all biochemical markers of bone turnover compared to placebo (P< 0.05), except for urinary free deoxypyridinoline. Both treatment groups experienced similar improvement in Harris hip and SF-36 UK outcome scores. The frequency of adverse events was similar in each treatment group (placebo 7/24, pamidronate 8/23, P> 0.05). Acute periprosthetic bone loss following THA is due to a transient increase in bone turnover. A single dose infusion of pamidronate in the early post-operative period significantly reduces this bone loss, and is well tolerated

Background: Joint replacements are being performed on ever younger patients at a time when average expectancy of life is continuing to rise. Any reduction in the strength and mass of periprosthetic bone could threaten the longevity of implant by predisposing to loosening and migration of prosthesis, periprosthetic fracture and problems in revision arthroplasty. Aims and Objectives: This study aims to analyse and compare prospectively the femoral periprosthetic stress-shielding around 4/5th and 1/3rd porous coated cementless femoral stems in patients undergoing unilateral cementless total hip replacement done using DEXA scan by quantifying the changes in bone mineral density around femoral component. Material and Method: Femoral periprosthetic bone mineral density was measured in the seven Gruen Zones with DEXA scan at 2 weeks, 1 years and 2 years after surgery in 60 patients who had undergone unilateral cementless total hip replacement, of which 30 patients had been implanted with 4/5th porous coated stems and other 30 patients with 1/3rd porous coated stems. Results: At both one and two years postoperatively, bone loss due to stress-shielding was seen in both stems with maximum loss in zone VII and minimum in zone III, IV, V. The maximum mean percentage bone mineral density loss in 4/5th porous coated stems in zone VII was 16.03% at one year and 22.42% at 2 years as compared to loss of 10.07% and 16.01% in 1/3rd porous coated stems. Increased bone loss was seen in patients who had larger diameter stem (> 13.0 mm) and in patients with low bone mineral density in the unoperated hip. Conclusion: Bone loss as a result of stress-shielding is more pronounced in 4/5th porous coated stems as compared to 1/3rd porous coated stems

Background: Joint replacements are being performed on ever younger patients at a time when average expectancy of life is continuing to rise. Any reduction in the strength and mass of periprosthetic bone could threaten the longevity of implant by predisposing to loosening and migration of prosthesis, periprosthetic fracture and problems in revision arthroplasty. Aims & Objectives: This study aims to analyse and compare prospectively the femoral periprosthetic stress-shielding around 4/5th and 1/3rd porous coated cementless femoral stems in patients undergoing unilateral cementless total hip replacement done using DEXA scan by quantifying the changes in bone mineral density around femoral component. Material & Method: Femoral periprosthetic bone mineral density was measured in the seven Gruen Zones with DEXA scan at 2 weeks, 1 years and 2 years after surgery in 60 patients who had undergone unilateral cementless total hip replacement, of which 30 patients had been implanted with 4/5th porous coated stems and other 30 patients with 1/3rd porous coated stems. Results: At both one and two years postoperatively, bone loss due to stress-shielding was seen in both stems with maximum loss in zone VII and minimum in zone III, IV, V. The maximum mean percentage bone mineral density loss in 4/5th porous coated stems in zone VII was 16.03% at one year and 22.42% at 2 years as compared to loss of 10.07% and 16.01% in 1/3rd porous coated stems. Increased bone loss was seen in patients who had larger diameter stem (> 13.0 mm) and in patients with low bone mineral density in the unoperated hip. Conclusion: Bone loss as a result of stress-shielding is more pronounced in 4/5th porous coated stems as compared to 1/3rd porous coated stems

Background: Joint replacements are being performed on ever younger patients at a time when average expectancy of life is continuing to rise. Any reduction in the strength and mass of periprosthetic bone could threaten the longevity of implant by predisposing to loosening and migration of prosthesis, periprosthetic fracture and problems in revision arthroplasty. Aims & Objectives: This study aims to analyse the femoral periprosthetic stress-shielding following unilateral cementless total hip replacement using DEXA scan by quantifying the changes in bone mineral density around femoral component. Materials and Methods: Femoral periprosthetic bone mineral density was measured in the seven Gruen Zones with DEXA scan at 2 weeks, 1 year and 2 year after surgery in 60 patients who had undergone unilateral cementless total hip replacement, of which 30 patients had been implanted with 4/5th porous coated CoCr stems and other 30 patients with 1/3rd porous coated titanium alloy stems. Results: At both one and two years postoperatively, bone loss due to stress-shielding was seen in both stems with maximum loss in zone VII and minimum in zone III, IV, V. The maximum mean percentage bone mineral density loss in 4/5th porous coated CoCr stems in zone VII was 16.03% at one year and 22.42% at 2 years as compared to loss of 10.07% and 16.01% in 1/3rd porous coated Ti alloy stems. Increased bone loss was seen in patients who had larger diameter stem (> 13.0 mm) and in patients with low bone mineral density in the unoperated hip. Conclusion: Bone loss as a result of stress-shielding is more pronounced in 4/5th porous coated CoCr stems as compared to 1/3rd porous coated titanium alloy stems

An argument against the use of canal-filling, customised femoral stems has been that such implants have a large cross-sectional area and therefore are stiffer than standard, uncemented implants, thus inducing more stress shielding and bone loss in the proximal femur. The purpose of this study was to evaluate the association between the volume of the femoral stem and the change in periprosthetic bone mineral density (BMD) measured with DEXA. Material and methods. Forty-eight patients with a mean age of 46 years had a THR using a customised femoral stem (Unique, SCP, Norway). BMD was measured in the 7 Gruen zones postoperatively and after then 3, 6, 12 and 24 months. Based on the 3-D computer model of the implant the volume of the intrafemoral part of the stem was computed. The association between the relative change in BMD at the 2 years follow-up and the volume of the stem was assessed using correlation analyses. Results. No statistically significant correlation between the volume of the intrafemoral part of the stem and change in BMD could be found for the most proximal zones (1, 6 and 7). Neither was there an association between the postoperative BMD value and the degree of stress shielding. However, a weak correlation between the volume of the stem and change in BMD was found in Gruen zones 2, 4, 5 and for the overall BMD in all zones. Discussion. No consistent or strong association between the volume of the femoral stem and the periprosthetic stress shielding at 2 years postoperatively was found in this study. In particular, the bone remodeling in the most proximal part of the femur was not correlated to the size of the stem. Contrary to other studies, our findings imply that stem size or stiffness is not a major determinant for proximal femoral stress shielding following THR

Background: Joint replacements are being performed on ever younger patients at a time when average expectancy of life is continuing to rise. Any reduction in the strength and mass of periprosthetic bone could threaten the longevity of implant by predisposing to loosening and migration of prosthesis, periprosthetic fracture and problems in revision arthroplasty. Aims & Objectives: This study aims to analyse the femoral periprosthetic stress-shielding following unilateral cementless total hip replacement using DEXA scan by quantifying the changes in bone mineral density around femoral component over a period of one year and identify the factors influencing the bone loss. Material & Method: Femoral periprosthetic bone mineral density was measured in the seven Gruen Zones with DEXA scan at 2 weeks, 3 months and 1 year after surgery in 20 patients who had undergone unilateral cementless total hip replacement, of which 10 patients had been implanted with 4/5. th. porous coated CoCr stems and other 10 patients with 1/3. rd. porous coated titanium alloy stems. Results: At both 3 months and one year postoperatively, bone loss due to stress-shielding was seen in both stems with maximum loss in zone VII and minimum in zone III, IV, V. The maximum mean percentage bone mineral density loss in 4/5. th. porous coated CoCr stems in zone VII was 16.03% at 3 month and 22.42% at 1 year as compared to loss of 10.07% and 16.01% in 1/3. rd. porous coated Ti alloy stems. Increased bone loss was seen in patients who had larger diameter stem (> 13.0 mm) and in patients with low bone mineral density in the unoperated hip. Conclusion: Bone loss as a result of stress-shielding is more pronounced in 4/5. th. porous coated CoCr stems as compared to 1/3. rd. porous coated titanium alloy stems

We analysed periprosthetic bone mineral density (BMD) by dual-energy X-ray absorptiometry (DEXA) in patients after uncemented total hip arthroplasty (THA) (press-fit CLS Spotorno stem). Only patients with good clinical outcome (Merle d‘ Aubigne score > 12) were included to obtain normative data for regular bone response. Two separate studies were performed: A prospective longitudinal study over a time period of 7 years (group A) (n = 26 patients: 12 women, 14 men) and an additional cross-sectional study, mean follow-up13 years (10 to 15 years) (group B) (n = 35 patients: 18 women, 17 men). Regions of interest were defined according to Gruen (ROI 1–7) and as netto average ROI (NETAVG) for the periprosthetic femoral bone. After the initial remodelling process, BMD at 1 year was compared to the 7-year (longitidinal) and to the 13-year (cross-sectional) follow-up values of the affected limb to determine long term periprosthetic changes of bone mineral density. The longitudinal study (group A) showed BMD values of 91.1% and 92.8% after 1 year, 91.2% and 90.2% after 7 years compared to the initial post-operative values for women and men, respectively. ROIs around the proximal stem (ROI 1 and 7) showed the lowest absolute values and decreased most during follow-up (ROI 1: 80.7% and 84.5%, ROI 7: 71.1% and 75.5% after 7 years, for women and men respectively). In the cross-sectional study (group B) BMD was determined 89.1% and 87.8% after 13 years compared to the initial values of group A for women and men. Distribution of BMD in ROIs 1-7 (group B) showed no significant changes compared to the 1 year and 7 year results of group A. The results reflect normative long term changes in the periprosthetic bone after implantation of THA in defined ROIs of a well functioning tapered corundum-blasted titanium stem