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

Summary

Denosumab contributed to the restoration of proximal periprosthetic bone loss around the femoral stem that were measured using a DEXA, especially in zone 7, at 1 year after cementless THA in elderly osteoporotic patients.

Introduction

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.

Methods

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 6 months and at 1 year after surgery. No difference was found between the two groups referred to the patient’s demographic data.

Results

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.

Conclusion

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 6–12 months 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.

     

骨矿改变在人工全髋关节置换术的监测

目的：研究人工全髋关节置换术后髋周骨矿含量的改变。方法：对骨水泥型人工全髋关节置换的25例27髋,在术后不同时段用DEXA测定髋周5个区域的骨矿含量,并与其各自合适的对照作配对样本t检验。结果：术后1个月内（平均23d)测定组显示第4区骨矿量显著增加（P＜0．05）;术后4－6月（平均4．4月）和7－12月测定组显示5个区骨矿量无显著增减（P＞0．05）;术后14－49月（平均27．4月）测定组显示第2区和第5区骨矿量显著降低（P＜0．05）;第1区也有明显降低趋势（P＝0．064）。结论：骨水泥型人工全髋置入后髋周承重部位骨矿量在12月内改变不大;术后约2年在髋臼周围和股骨小粗隆部骨矿明显丢失,与置入假体后产生应力遮挡可能有关。     

DXA Scanning of Acetabulum in Patients With Cementless Total Hip Arthroplasty

The aim of this study was to evaluate the reproducibility of bone mineral density (BMD) measurements of the periprosthetic bone in patients with hemispherical acetabular cups in cementless total hip arthroplasty (THA). Thirty patients were treated for primary osteoarthrosis with cementless THA. Dual-energy X-ray absorptiometry (DXA) scanning was performed with a pencil-beam bone densitometer (Norland XR-36). Accuracy and reproducibility was determined by double measurements of BMD in four regions of interest (ROI). The influence of patient postures including various pelvic inclination angles was evaluated as well. Pitman test for a combined netROI revealed a standard deviation ratio of 3.2 for the anterio-posterior scans related to the lateral position. The Wilkinson ROIs showed a high intraobserver agreement. With pelvic tilt increasing until 20 degrees , the precision of DXA scanning decreased. In conclusion, reproducibility of DXA scanning was high. This study demonstrated that the patients can be scanned in the supine position, and BMD measurement of the periacetabular bone can be performed using the Wilkinson model with four rectangular ROIs.     

Different loss of BMD using uncemented press-fit and whole polyethylene cups fixed with cement: repeated DXA studies in 96 hips randomized to 3 types of fixation

Background In cemented THA, aseptic loosening of the cup is more common than loosening of the stem, while periprosthetic osteolysis of the socket resulting in difficult reconstruction problems has emerged as the most significant problem with cementless cup fixation.

Patients and methods 90 patients (96 hips) scheduled for THA were stratified in three groups according to the method of fixation of the acetabular component: acrylic bone cement with fluoride (Cemex-F), porous-coated press-fit cup with ceramic coating (Trilogy, uncemented) and acrylic cement with gentamicin (Palacos). All patients received the Spectron EF stem. Acetabular bone mineral density was measured with dual-energy X-ray absorptiometry (DXA) 1 week postoperatively, and after 12 and 24 months. The periprosthetic BMD was evaluated in 5 ROIs positioned around the acetabular component.

Results In the uncemented sockets, the BMD had decreased proximally and medially to the cup after 2 years. The difference was significant in the proximal region as compared to the control group (Palacos). No difference was noted between the 2 groups with cemented components after 2 years. Stepwise linear regression analysis showed that loss of periprosthetic BMD in the proximal high-pressure region after 2 years increased with higher postoperative BMD and when the uncemented design had been used.

Interpretation Contrary to previous studies of cemented stems, the use of fluoride cement did not influence the periprosthetic BMD 2 years after the examination. Increased loss of BMD with use of uncemented press-fit cups in the region in which osteolytic lesions are commonly found suggests that stress shielding may initiate the development of this complication. Longer follow-up will, however, be necessary to substantiate this hypothesis.     

Comparison of allograft-prosthetic composite reconstruction and modular prosthetic replacement in proximal femur bone tumors: Functional assessment by gait analysis in 20 patients

Background?In cemented THA, aseptic loosening of the cup is more common than loosening of the stem, while periprosthetic osteolysis of the socket resulting in difficult reconstruction problems has emerged as the most significant problem with cementless cup fixation.

Patients and methods?90 patients (96 hips) scheduled for THA were stratified in three groups according to the method of fixation of the acetabular component: acrylic bone cement with fluoride (Cemex-F), porous-coated press-fit cup with ceramic coating (Trilogy, uncemented) and acrylic cement with gentamicin (Palacos). All patients received the Spectron EF stem. Acetabular bone mineral density was measured with dual-energy X-ray absorptiometry (DXA) 1 week postoperatively, and after 12 and 24 months. The periprosthetic BMD was evaluated in 5 ROIs positioned around the acetabular component.

Results?In the uncemented sockets, the BMD had decreased proximally and medially to the cup after 2 years. The difference was significant in the proximal region as compared to the control group (Palacos). No difference was noted between the 2 groups with cemented components after 2 years. Stepwise linear regression analysis showed that loss of periprosthetic BMD in the proximal high-pressure region after 2 years increased with higher postoperative BMD and when the uncemented design had been used.

Interpretation?Contrary to previous studies of cemented stems, the use of fluoride cement did not influence the periprosthetic BMD 2 years after the examination. Increased loss of BMD with use of uncemented press-fit cups in the region in which osteolytic lesions are commonly found suggests that stress shielding may initiate the development of this complication. Longer follow-up will, however, be necessary to substantiate this hypothesis.     

Pattern of Periprosthetic Bone Remodeling Around Stable Uncemented Tapered Hip Stems: A prospective 84-month follow-up study and a Median 156-month Cross-Sectional Study with DXA

Bone resorption in the proximal femur is commonly seen after total hip arthroplasty (THA). With dual energy X-ray absorptiometry (DXA), the amount of bone mass (BMD) after implantation of a total hip stem can be precisely determined. However, prospective evaluation of the change of bone mass around the stem is only available for selected stems and short-term follow-up (up to 36 months). We analyzed BMD in patients who had undergone uncemented THA by DXA. Only patients with good clinical outcome (Merle d Aubigné score > 12) were included to obtain normative data for regular bone response. Two separate studies were performed: a prospective longitudinal study over 84 months with baseline values acquired within the first postoperative week (group A) (n = 26 patients) and a separate cross-sectional study, median follow-up 156 (124-178) months (group B) (n = 35 patients). Regions of interest were defined according to Gruen (ROI 1-7) and as net average ROI (net avg) for the periprosthetic femoral bone. After the initial remodeling process (12 months), BMD was compared to the 84-month (longitudinal) and the 156-month (cross-sectional) follow-up values to determine long-term periprosthetic changes of bone mineral density. The longitudinal study (group A), after the initial bone remodeling, showed no relevant further bone loss for women and men with BMD values 1.19 ± 0.15 and 1.40 ± 0.19, respectively, 12 months (women 89.8%, men 93.6%), and 1.19 ± 0.13 and 1.36 ± 0.18, respectively, after 84 months (women 90.0%, men 91.3%) (P = 0.98, P = 0.08,) respectively. The distribution of the BMD around the stem changed during the first 12 months. The ROIs around the proximal stem (ROI 1 and 7) showed the lowest absolute values at the 12-month follow-up and BMD in ROI 7 decreased most during the further follow-up until 84 months. The cross-sectional study (group B) showed no significant difference in BMD (net avg) values at a median of 156 months follow-up compared to the 12-month values (group A) (women: P = 0.77, men: P = 0.44). Initial BMD, implant diameter, and body mass index did not influence BMD loss (net avg) in this study, whereas age showed a weak correlation with BMD loss. The results show that after the initial remodeling process, no relevant further bone loss (net avg) occurs up to 84 months postsurgery, and values after a median of 156 months are similar. Normative long-term changes in the periprosthetic bone can be demonstrated in defined ROIs after implantation of a tapered corundum-blasted titanium stem with a good clinical result.     

Measurement of Bone Density Around Total Knee Arthroplasty Using Fan-Beam Dual Energy X-ray Absorptiometry

The clinical survival of joint arthroplasties is clearly associated with the quality of surrounding bone environment. Bone mineral density (BMD) is an important measure of bone strength and quality. Periprosthetic BMD can be measured by using dual-energy X-ray absorptiometry (DXA) with special software algorithms. We studied short-term reproducibility of the periprosthetic BMD measurements after total knee arthroplasty (TKA) in 30 patients with primary osteoarthrosis. The operated knees and the contralateral control knees were measured twice and the results were expressed as a coefficient of variation (CV%). The average precision error was 3.1% in femoral regions of interest (ROI) and 2.9% in tibial ROIs after TKA. In the prosthesis-free control knees, CV% were similar; 3.2% and 2.5%, respectively. The best precision was found in the femoral diaphyses above the implant (1.3%), whereas the least reproducible BMD was determined in the patellar region of the TKA knees (6.9%). Our results confirm that DXA measures precisely small bone mineral changes around TKA and makes it possible to follow bone remodeling DXA and may provide a feasible method for monitoring TKA in the future. Received: 16 September 1998 / Accepted: 29 February 2000     

Periprosthetic DXA after total hip arthroplasty with short vs. ultra-short custom-made femoral stems

Background and purpose Dual-energy X-ray absorptiometry (DXA) analysis of the 7 periprosthetic Gruen zones is the most commonly used protocol to evaluate bone remodeling after the implantation of conventional femoral stems. We assessed the value of DXA after cementless primary total hip arthroplasty (THA) by comparing the effect of progressive shortening of the stem of two femoral implants on periprosthetic bone remodeling using a specifically developed protocol of analysis with 5 periprosthetic regions of interest (ROIs).Patients and methods Bone mineral density (BMD) was evaluated in 37 patients in the plateau stage, 3 years after THA. Two femoral implants featuring conceptually new designs and surgical technique were tested: types 1 and 2, characterized by extremely short stem and virtual absence of distal stem, respectively.Results We found that progressive shortening of the femoral stem produces more proximal loading, which effectively preserves metaphyseal bone stock and increases periprosthetic BMD in the medial ROIs over time. In the type 2 group, higher absolute BMD values were observed in medial ROIs 4 and 5. No differences were found in ROIs 1, 2, and 3.Interpretation This study shows the flexibility of DXA in adapting the protocol of periprosthetic analysis to the specific requirements of new implant designs, and it shows its high sensitivity in evaluation of the biological response of bone to changes in implant shape.     

Changes of periprosthetic bone mineral density in cementless bicontact stem implantation; influence of different parameters--a prospective 4-year follow-up

AIM: This prospective study describes the periprosthetic BMD (bone mineral density) after implantation of the cementless Bicontact stem over a period of 4 years. Additionally, the influence of several relevant parameters like age, sex, BMI (body mass index) and the influence of the stem-size on the periprosthetic BMD course were investigated. METHOD: Measurement of the periprosthetic BMD in 36 patients (15 female, 21 male) in a prospective longitudinal study over 4 years with DEXA (dual energy X Ray absorptiometry) of the proximal Gruen zones 1 and 7. RESULTS: We found a good precision of the method in vivo with a CV (coefficient of variation) of 1.04 %. There was a decline of the periprosthetic BMD at the whole proximal stem (ROI 0) of 20 % in the first 6 months. Afterwards there was a significant increase at the lateral stem (ROI 1) of 3.46 %, in contrast no significant change could be found medially, maybe as a result of a more lateral induction of power. The investigated parameters BMI, age and sex had no influence on the relative course of mineralisation. At stem sizes bigger than 15 the decline of BMD was significantly larger than at the stem sizes smaller than 15. CONCLUSION: DEXA is a sufficiently precise method to investigate periprosthetic BMD. The postoperative periprosthetic course of mineralisation and the extent of BMD loss in the first 6 months after the Bicontact stem is similar to other periprosthetic BMD courses of prosthesis with a similar design. The course of mineralisation in "smaller" stems is obviously more auspicious than the course of "bigger" stems.     

Bone remodelling around HA-coated acetabular cups

This study was designed to investigate bone remodelling around the cup in cementless THA. Previous studies indicate an advantage of better sealing of the bone-prosthesis interface by HA/TCP coating of implants, inhibiting polyethylene-induced osteolysis. One hundred patients gave informed consent to participate in a controlled randomized study between porous coated Trilogy versus Trilogy Calcicoat (HA/TCP coated). The cup was inserted in press-fit fixation. The femoral component was a cementless porous coated titanium alloy stem (Bi-Metric), with a modular 28-mm CrCo head. The Harris Hip Score (HHS) and bone mineral density (BMD) determined by DEXA scanning were used to study the effect. Measurements revealed no difference between the two groups after 3 years either in the clinical outcome or in terms of periprosthetic bone density. Patients with a body mass index above normal regained more bone mineral than patients with normal weight. This finding supports the assumption that load is beneficial to bone remodelling.     

Total hip arthroplasty using cementless grit-blasted femoral component: a minimum 10-year follow-up study

The grit-blasted cementless Spotorno (CLS) stem, which has excellent survival rates up to 10 years, is widely used in total hip arthroplasty (THA). We investigated the survivorships of CLS stems in THA at a minimum follow-up of 10 years and sought to identify factors that influence outcomes. A total of 227 hips of 191 patients who underwent cementless THA with a CLS stem were retrospectively reviewed at a mean follow-up of 12.3 years. All patients were evaluated clinically and radiographically according to implant type and surgery-related and patient-related factors. Survivorship was 97.2% when femoral revision for any reason was defined as the end point. Femoral revisions were performed in 3 hips because of periprosthetic fractures. Survivorship for all hips, using revision for any reason as the end point, was 92.6%. Two metal-on-metal THAs were revised because of aseptic loosening or osteolysis around the cup. No significant differences were evident for type of stem, type of bearing surface, stem alignment, or patient-related factors. However, a canal fill index of 80% or less was found to affect cortical remodeling, subsidence, and a change in stem position of 5° or more, which indicates that care must be taken not to undersize stems. In addition, in view of the revisions performed, bearing surfaces appear to importantly influence THA survivorship.     

Periprosthetic bone remodeling around a prosthesis for distal femoral tumors: longitudinal follow-up

Serial measurements using dual-energy x-ray absorptiometry (DEXA) were undertaken to evaluate progressive periprosthetic bone loss in patients treated for primary bone tumors of the distal femur using an uncemented tumor prosthesis. Twelve patients underwent sequential DEXA analysis on average 26.5 and 90.9 months postsurgery. Changes in bone mineral density were measured in regions of interest (ROIs) around the prosthesis stem. The test-retest reliability coefficient (r) ranged from 0.92 to 0.99 for all ROI. In the most distal ROI (ROI1), 10 of 11 patients with 2 measurements showed no change or a small increase in absolute bone mineral density. The results in other ROIs were similar. This longitudinal DEXA data suggest that progressive bone resorption is not problematic with an uncemented distal femur endoprosthesis at intermediate follow-up. Key words: DEXA, stress shielding, uncemented endoprothesis, tumor, bone loss.     

生物固定C2型股骨柄对股骨近端应力遮挡影响的临床研究

目的 探讨生物固定C2型股骨柄人工全髋关节对股骨近端假体周围骨丢失方面的影响。方法31例C2型股骨柄全髋关节置换术（THA）后患者得到完整随访，包括X线片、Harris评分以及双能X线骨密度仪（DEXA）测量股骨近端假体周围骨密度，采用Gruen七区法，非手术侧作为对照。结果31例患者HHS评分优秀22例，良好8例，一般1例。X线显示所有柄都是稳定的，X线上未见明显假体周围骨密度改变。DEXA测量结果表明手术侧骨密度较非手术侧均出现下降，范围在2．42％～27．4％，平均6．67％，其中Gruen 4区和7区的骨密度下降有统计学意义（t值分别是-5．52和-7．08，P〈0．01）。结论 C2型股骨柄术后2年临床疗效较好，DEXA在评估THA的术后假体周围骨密度方面比普通平片更敏感，THA术后股骨近端假体周围的骨丢失是存在的，尤其在股骨距区下降明显。假体周围骨丢失与假体设计存在关系。     

Female patients with low systemic BMD are prone to bone loss in Gruen zone 7 after cementless total hip arthroplasty: A 2-year DXA follow-up of 39 patients

Background and purpose Factors that lead to periprosthetic bone loss following total hip arthroplasty (THA) may not only depend on biomechanical implant-related factors, but also on various patient-related factors. We investigated the association between early changes in periprosthetic bone mineral density (BMD) and patient-related factors.Patients and methods 39 female patients underwent cementless THA (ABG II) with ceramic-ceramic bearing surfaces. Periprosthetic BMD in the proximal femur was determined with DXA after surgery and at 3, 6, 12, and 24 months. 27 patient-related factors were analyzed for their value in prediction of periprosthetic bone loss.Results Total periprosthetic BMD was temporarily reduced by 3.7% at 3 months (p < 0.001), by 3.8% at 6 months (p < 0.01), and by 2.6% at 12 months (p < 0.01), but recovered thereafter up to 24 months. Preoperative systemic osteopenia and osteoporosis, but not the local BMD of the operated hip, was predictive of bone loss in Gruen zone 7 (p = 0.04), which was the only region with a statistically significant decrease in BMD (23%, p < 0.001) at 24 months. Preoperative serum markers of bone turnover predicted the early temporary changes of periprosthetic BMD. The other patient-related factors failed to show any association with the periprosthetic BMD changes.Interpretation Female patients with low systemic BMD show greater bone loss in Gruen zone 7 after cementless THA than patients with normal BMD. Systemic DXA screening for osteoporosis in postmenopausal patients before THA could be used to identify patients in need of prophylactic anti-resorptive therapy.     

Cementless Spotorno tapered titanium stems

We evaluated the clinical and radiographic results of the first consecutive 154 implantations of a cementless, double-tapered straight femoral stem (cementless Spotorno (CLS), Sulzer Orthopedics) in 141 patients under the age of 55 (mean 47 (13–55)) years. After a mean follow-up of 12 (10–15) years, 11 patients (11 hips) had died and 7 (7 hips) could not be located. 5 patients (5 hips) underwent femoral revision—1 for infection, 1 for periprosthetic fracture and 3 for aseptic loosening of the stem. The overall survival rate of the stem was 97% at 12 years (95% confidence limits, 93%–100%), and survival with femoral revision for aseptic loosening as an end point 98 (95–100)%. The survival rate of the acetabular components was 78 (71–85) % after 12 years. The median Harris hip score at follow-up was 84 points. None of the patients had thigh pain. Radiolucent lines in Gruen regions 1 and 7 were present in 21 hips (17%). 2 hips had radiolucent lines in regions 2–6 on anteroposterior (AP) radiographs. No femoral osteolysis was detected.

The mid- to long-term survival with this type of femoral component is excellent and compares favorably with cemented stems in this age group. However, the high rate of cup loosening and the low Harris hip scores are a concern in this subgroup of young patients.     

Five-year DEXA study of 88 hips with cemented femoral stem

We performed repeated dual-energy X-ray absorptiometry (DEXA) measurements over five years in a homogeneous patient population to study the effect of a cemented stem on proximal femoral bone remodelling. Data from 88 patients (88 hips) implanted with total hip arthroplasty (THA) prostheses were extracted from three randomised studies. Femoral bone mineral density (BMD) was measured using a Lunar DPX-IQ densitometer for five years postoperatively. At one year the BMD changes had decreased between −2.0% [region of interest (ROI) 1] and −11.5% (ROI 7). During the follow-up period the BMD initially increased during the second year and thereafter decreased again in ROIs 5, 6 and 7. The loss of BMD at five years was more pronounced in region 7 (12.9%) and decreased with increasing age, total hip replacement (THR) on the right side and decreasing weight of the patient. We found that after the initial phase of early bone loss a period of recovery follows. Thereafter the BMD decreases again, which probably reflects the normal ageing of bone after uncomplicated cemented THA.     

Periprosthetic bone loss after cemented total hip arthroplasty

In this prospective 5-year study, we determined the periprosthetic bone loss after cemented total hip arthroplasty (THA) in 15 patients using dual energy X-ray absorptiometry (DXA). A reduction in the periprosthetic bone mineral density (BMD) of 5-18% occurred in all Gruen regions, or regions of interest (ROI), during the first 3 months after THA. The bone loss continued up to 6 months in almost all ROIs. From 1 to 5 years, we found only minor changes in BMD in periprosthetic bone. After the follow-up, the mean greatest bone loss (26%) was seen in the femoral calcar area. The reduction in mean BMD was 5% in men, and 16% in women. The lower the preoperative BMD, the higher was the postoperative bone loss. We found that after the phase of acute bone loss, further loss was minimal, reflecting merely the normal ageing of bone after uncomplicated THA.     

Cementless Spotorno tapered titanium stems

We evaluated the clinical and radiographic results of the first consecutive 154 implantations of a cementless, double-tapered straight femoral stem (cementless Spotorno (CLS), Sulzer Orthopedics) in 141 patients under the age of 55 (mean 47 (13-55)) years. After a mean follow-up of 12 (10-15) years, 11 patients (11 hips) had died and 7 (7 hips) could not be located. 5 patients (5 hips) underwent femoral revision—1 for infection, 1 for periprosthetic fracture and 3 for aseptic loosening of the stem. The overall survival rate of the stem was 97% at 12 years (95% confidence limits, 93%-100%), and survival with femoral revision for aseptic loosening as an end point 98 (95-100)%. The survival rate of the acetabular components was 78 (71-85) % after 12 years. The median Harris hip score at follow-up was 84 points. None of the patients had thigh pain. Radiolucent lines in Gruen regions 1 and 7 were present in 21 hips (17%). 2 hips had radiolucent lines in regions 2-6 on anteroposterior (AP) radiographs. No femoral osteolysis was detected.

The mid- to long-term survival with this type of femoral component is excellent and compares favorably with cemented stems in this age group. However, the high rate of cup loosening and the low Harris hip scores are a concern in this subgroup of young patients.     

Periprosthetic bone loss after cemented total hip arthroplasty: a prospective 5-year dual energy radiographic absorptiometry study of 15 patients

In this prospective 5-year study, we determined the periprosthetic bone loss after cemented total hip arthroplasty (THA) in 15 patients using dual energy X-ray absorptiometry (DXA). A reduction in the periprosthetic bone mineral density (BMD) of 5-18% occurred in all Gruen regions, or regions of interest (ROI), during the first 3 months after THA. The bone loss continued up to 6 months in almost all ROIs. From 1 to 5 years, we found only minor changes in BMD in periprosthetic bone. After the follow-up, the mean greatest bone loss (26%) was seen in the femoral calcar area. The reduction in mean BMD was 5% in men, and 16% in women. The lower the preoperative BMD, the higher was the postoperative bone loss. We found that after the phase of acute bone loss, further loss was minimal, reflecting merely the normal ageing of bone after uncomplicated THA.