髋部骨矿骨密度在人工全髋关节置换后的改变

目的：观察人工全髋关节置换术后在假体周围的髋骨骨矿量（BMC）骨密度（BMD）的改变规律。方法：采用DPX－L骨密度仪连续追踪调查52例人工全髋关节置换术后3、6、12、24和36个月的髋骨假体周围的BMC和BMD，以术前、后健侧髋为对照，进行分析研究。结果：发现术后3、6个月BMC和BMD均较术前下降（P≤0．05），患髋经12－24个月运动练习，BMC和BMD逐渐增加，至36个月时达到或接近健侧髋骨水平并获得稳定（P≤0．01）。结果显示BMC和BMD的改变与人工全髋关节的固定方式即骨水泥固定与生物型固定无明显关系（P＜0．01）。结论：人工全髋关节置换术后6个月内BMC和BMD呈不同程度下降，患髋经12－24个月运动练习，BMC和BMD逐渐增加，至36个月时达到健侧髋骨的水平并获得稳定，与固定方式无明显关系。     

髋臼骨折后创伤性关节炎全髋关节置换疗效研究

[目的]比较髋臼骨折经切开复位内固定治疗和保守治疗后发生创伤性关节炎行全髋关节置换术的远期疗效。[方法]30例（32髋）髋臼骨折患者行保守治疗或切开复位内固定术，髋臼骨折后平均间隔7年5个月（5个月～29年）发生创伤性关节炎，对32髋行全髋关节置换术治疗，手术时平均51岁（25～78岁）。应用非骨水泥人工关节29髋，骨水泥型2髋，混合型1髋。术后平均随访8年9个月（4～17年）。[结果]手术组和保守组在骨移植、翻修率、手术时间和异位骨化发生率方面无显著差异（P〉0．05）；失血量有统计学差异（P〈0．05），保守组失血量较多。手术组和保守组临床疗效无显著性差异。[结论]髋臼骨折行保守治疗和手术治疗后发生创伤性关节炎需行人工关节置换治疗，两者远期疗效相似，非骨水泥型关节置换疗效较好。     

小切口全髋关节置换的手术体会

[目的]探讨小切口人工全髋关节置换手术的优缺点。[方法]比较32例37髋小切口人工全髋关节置换术与普通切口人工全髋关节置换术在切口长度、手术时间、术中出血量、术后引流量、住院时间及并发症等方面的异同。[结果]小切口组平均切口长度为7．7cm，普通切口组为11．5cm（P〈0．05）；小切口组平均手术时间为95min，普通切口组为51min（P〈0．05）；小切口组术中平均出血量为380ml，普通切口组为299ml（P〈0．05）；小切口组及普通切口组在术后引流量及住院时间方面无显著性差异（P〉0．05）；小切口组1例术中出现大转子尖骨折、股骨颈截骨过多、髋臼内凸，1例因髋臼安放角度异常于术后第3d出现髋关节脱位，行扩大切口调整髋臼假体角度后恢复正常；普通切口组术中、术后无1例出现并发症。[结论]与普通长度切口全髋关节置换手术相比，小切口手术在出血量、组织损伤程度、手术时间方面并无明显优势；由于切口小，术野受限，手术操作比较困难，易出现假体安装位置异常等问题。在熟练做好普通切口全髋置换手术、不增加手术损伤的前提下，可尽量减小手术切口长度，没有必要刻意追求小切口全髋置换手术。     

全髋关节表面置换术后股骨近端骨密度的变化

目的评价全髋关节表面置换术对股骨近端骨量变化的影响。方法2002年7月至2005年6月,对行全髋关节表面置换术（表面置换组）和人工全髋关节置换术（全髋置换组）各26例患者作为研究对象,均在术前、术后3、6、12和24个月时对股骨近端按Gruen分区设为7个测量感兴趣区,表面置换组加股骨颈外上和内下区,应用双能X线吸收测定仪测定骨密度,比较两组术前和术后股骨近端骨密度变化。结果术后3、6、12和24个月时,表面置换组股骨近端骨密度分别降低5．8％、4．9％、2．6％和0．4％;测量感兴趣区1的骨密度术后6个月时降至89．7％,至24个月时增至103．8％;测量感兴趣区7的骨密度术后6个月时降至95．1％,24个月时增至103．7％;股骨颈部骨密度在术后6个月时即可恢复至术前水平,股骨颈外上区的骨密度术后3个月时降至97．1％,术后24个月时增至107．4％（P〈0．05）;股骨颈内下区的骨密度术后24个月时增至117．9％（P〈0．05）。全髋置换组股骨近端骨密度分别降低7．0％、10．6％、1．0％和4．1％。测量感兴趣区1的骨密度术后6个月降至90．8％,术后24个月时为94．4％;测量感兴趣区7术后3个月降至94．2％,术后24个月时为96．7％。结论全髋关节表面置换术后股骨近端骨量可以得到有效保存和恢复。     

聚乙烯微粒、细胞因子与人工髋关节松动的相关性研究

目的：研究聚乙烯微粒、细胞因子与人工髋关节松动的相关性。方法：根据假体的类型及假体中是否含有聚乙烯将38例人工髋关节翻修病例分为三组：全髋置换组和双动头组和一体式单动头组,对各组术中松动假体周围界膜组织进行光镜下炎性细胞计数的半定量分析和肿瘤坏死因子（TNF）的测定,分析人工髋关节无菌性松动与聚Zr烯微粒、细胞因子之间的相关关系。结果：根据Joseph的半定量标准,全髋置换组和双动头组在光镜下界膜中炎症反应程度无显著性差异（P〉0．05）,而单动头组与另外两组相比炎性细胞反应程度有显著性差异（P〈0．05）;经统计学分析显示全髋置换组与双动头组界膜中TNF含量无显著性差异（P〉0．05）,而全髋置换组与单动头组界膜中TNF含量有显著性差异（P〈O．05）,双动头组与单动头组界膜中TNF含量有显著性差异（P〈0．05）。结论：聚乙烯微粒比其他微粒（如金属微粒,水泥微粒等）可以刺激界膜中巨噬细胞释放更多的溶骨性的细胞因子TNF导致骨溶解加剧,人工关节的材料中尽量不用聚乙烯或改变聚乙烯的特性可以减少磨损微粒和其刺激巨噬细胞所释放溶骨性的细胞因子（如TNF）的数量,从生物学角度降低假体松动的发生率。     

微创小切口人工全髋关节置换术在晚期股骨头坏死治疗中的应用

目的探讨微创小切口人工全髋关节置换术在晚期股骨头坏死治疗中的应用价值。方法2003年3月始，采用微创技术治疗18例22髋国际骨循环学会（Association Research Circulation Osseous，ARCO）分期Ⅲ、Ⅳ期股骨头坏死患者，其中男13例，女5例，年龄24～57岁；体重指数（body mass index，BMI）24．6（17．1～30．1），术前髋关节Harris评分平均46分。均采用改良的后外侧切口、非骨水泥假体行人工全髋关节置换术（微创组）。与同期常规人工全髋置换术的18例22髋（对照组，术前髋关节Harris评分平均43分）进行比较，包括：围手术期出血量、切口长度及术后早期功能恢复情况等。结果术后两组均获随访6～20个月，平均11个月。对照组1髋术后2d脱位，微创组中无并发症发生；微创组手术切口长9．3cm（8．7～10．5cm），较对照组16．8cm（14．0～20．0cm）短，差异有统计学意义（P〈0.01）；两组术后随访6个月时Harris评分分别为92、90分，差异无统计学意义（P〉0.05）；手术时间相近，但围手术期出血量及引流量微创组较少，两组差异有统计学意义（P〈0．05）；微创组术后恢复较快。结论微创小切口全髋关节置换术，手术创伤小、出血少，术后恢复较快，但开展此手术的初期，应由有经验的医师及有相应设备的医院、有选择地用于晚期股骨头坏死患者的治疗。     

全髋关节和半髋关节置换术治疗股骨颈骨折的比较

目的评价全髋关节置换术和半髋关节置换术治疗股骨颈骨折的临床疗效并进行比较。方法回顾性分析53例（54髋）股骨颈骨折患者，男22例，女31例，年龄52—89岁（平均71岁），分别行全髋和半髋关节置换治疗，随访1—9年，平均5．4年。对其住院时间、手术时间、手术出血、术后失血、输血总量、有无并发症、术后功能恢复情况等作比较。结果全髋置换组手术时间明显长于半髋置换组（P〈0．05）；术中出血量、术后出血量、输血总量、住院时间长短均无明显统计学差异（P〉0．1）；术后并发症无明显统计学差异；半髋置换患者术后大腿痛明显多于全髋置换（P〈0．05）；术后功能恢复情况无明显统计学差异。结论半髋和全髋置换治疗股骨颈骨折的效果是满意的，对身体条件好，术后活动较多的或较为年轻的患者宜选择全髋关节置换术。     

人工全髋置换术中偏心距与软组织平衡

目的：分析标准股骨假体行人工全髋关节置换术股骨假体颈长和股骨矩保留对偏心距重建的作用，并研究偏心距重建对软组织平衡的影响。方法：68例（71髋，男30例，女38例；年龄17～89岁，平均63．5岁）行初次全髋关节置换术的患者并获得随访，采用Harris评分，Cybex-6000等速测定患髋外展肌力，测得偏心距、股骨矩、假体颈长，综合评估手术结果。结果：假体颈长对偏心距的影响较股骨矩大（t=3．07，P〈0．01），并与偏心距呈正相关关系（r=0．642，P〈0．001，但两者对Harris评分影响的差异无统计学意义（t=0．22，P〉0．05）。股骨头坏死患者术后偏心距较髋关节骨性关节炎患者和股骨颈骨折患者小（t=2．91，3．31，P〈0．01）。偏心距获得重建的髋关节术后外展肌力较偏心距重建不足者优（P〈0．05）。结论：采用标准股骨假体行全髋关节置换术，股骨假体颈长对人工全髋关节置换术后偏心距的重建作用大于股骨矩的保留，偏心距的重建在全髋关节置换术软组织平衡中主要起到增强术后外展肌力的作用。     

全髋关节置换手术入路对老年患者疗效的分析

目的：比较全髋关节置换术常用的后外侧入路（Gibson),外侧入路（Watson-Jones),及前外侧入路（Smith-Petersen),术中术后及功能的影响。方法：将1991－1999年我科治疗的132例60－82岁人工全髋关节假体置换术手术入路分成三组，比较其术中、术后，并发症及术后功能。结果：三组合并症的发生率与伤后手术时间无显差异（P＞0．05）。而并发症的发生与输血量，负重时间，功能评价，脱位率有显性差异（P＜0．05）。结论：在全髋关节置换术中，以髋关节外侧入路为最佳。     

严重异位骨化伴骨性强直的人工全髋置换术

目的：分析严重异位骨化伴髋关节骨性强直的人工全髋置换术的疗效及预防对策。方法：对12例髋关节严重异位骨化伴骨性强直者进行人工全髋置换术，术后经3－10年的随访。结果：所有病例经3－10（平均6．3）年随访，髋关节功能得到明显改善。结论：人工全髋置换术是髋关节严重异位骨化伴骨性强直的一种理想的治疗方法。     

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.     

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.     

Periprosthetic Mineralization Around Cementless Total Hip Endoprosthesis: Longitudinal Study and Cross-Sectional Study on Titanium Threaded Acetabular Cup and Cementless Spotorno Stem with DEXA

In a prospective longitudinal study over 2 years and a separate cross-sectional study more than 5 years after operation, we analyzed periprosthetic bone mineral density (BMD) after cementless total hip arthroplasty (THA) (press-fit cementless Spotorno stem, Mecron threaded acetabular cup) by dual-energy X-ray absorptiometry (DEXA). BMD was analyzed in a longitudinal prospective study (n = 53 patients: 29 women, 24 men) and in a separate cross-sectional study (n = 23 patients: 13 women, 10 men) with good clinical outcome (Merle d' Aubigne score > 12). Regions of interest were defined according to Gruen (ROI 1–7) and as netto average ROI (NETAVG I) for the periprosthetic femur, and according to De Lee and Charnley (ROI I-III) and as NETAVG II for the periprosthetic acetabulum. BMD during follow-up was compared with immediate postoperative values of the affected limb. Mean precision error (CV%) was 2.6 ± 0.5% for ROI 1–7 and 1.3 ± 0.9% for ROI I–III. BMD significantly decreased in the periprosthetic femur and acetabulum during the first 3 months after operation. At the femur, BMD (NETAVG I) for women and men, respectively, was 92.4% and 87.5% at 6 months, then 89.4% and 96.2% at 2 years. ROIs around the proximal stem showed the lowest absolute values and decreased most during follow-up (to 79.9% ROI 1 and 68.2% ROI 7, respectively). Mineralization around the cup (NETAVG II), respectively, amounted to 81.1%, 82.6% at 6 months, then 80.1% and 93.8% at 2 years. The medially placed ROI II demineralized most (respectively, 72.1% and 76.7%). More than 5 years after THA, BMD in the femur showed little change, but decreased significantly to 76.4% and 79.1%, respectively, around the cup (NETAVG II). DEXA is a useful method for analyzing changes of mineralization around cup and stem of cementless THA. The results reflect the different stress on the periprosthetic bone after implantation of THA in defined ROIs, supporting earlier reported good clinical results of the Spotorno stem and increased loosening rate of threaded acetabular cups after 5 years. Received: 31 March 1997 / Accepted: 7 August 1997     

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.     

Dose-dependent prevention of early periprosthetic bone loss by alendronate

AIM: Periprosthetic bone loss occurs in the first six months after total hip arthroplasty (THA) and is felt to be largely the result of initial operative irritation, immobilization, and stress shielding. This study (a prospective, randomized, open, blinded endpoint evaluation) aims at preventing bone loss around the stem with an oral bisphosphonate. METHOD: 66 healthy subjects with uncemented THA and low lumbar bone mass density (BMD) (negative T score) were treated post-operatively with alendronate as follows: n = 21 with 10 mg/d for 10 weeks (A), n = 21 20 mg/d for 5 weeks (B), n = 24 no treatment for controls (C). The periprosthetic BMD in the Gruen zones (ROI) was measured after the 2nd, 4th, 6th, and 12th month by DEXA as a percentage of the value measured one week after surgery. RESULTS: In C, there was significant bone loss in all ROI during the first months and a deficit of 29 % in ROI 7 following one year. In B, bone loss was completely prevented up to the second month, in ROI 7, a significant difference in comparison to C was registered for the entire year. In A, significant bone loss reduction during 12 months was seen. CONCLUSION: Alendronate, therefore, is capable of preventing initial periprosthetic bone loss. A dosage of 20 mg/d is required initially with daily treatment lasting at least 10 weeks.     

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.     

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.     

Measuring bone mineral density of the pelvis and proximal femur after total hip arthroplasty

We aimed to evaluate the precision and longitudinal sensitivity of measurement of bone mineral density (BMD) in the pelvis and to determine the effect of bone cement on the measurement of BMD in femoral regions of interest (ROI) after total hip arthroplasty (THA). A series of 29 patients had duplicate dual-energy x-ray absorptiometry (DXA) scans of the hip within 13 months of THA. Pelvic analyses using 3- and 4-ROI models gave a coefficient of variation (CV) of 2.5% to 3.6% and of 2.5% to 4.8%, respectively. Repeat scans in 17 subjects one year later showed a significant change in BMD in three regions using the 4-ROI model, compared with change in only one region with the 3-ROI model (p < 0.05). Manual exclusion of cement from femoral ROIs increased the net CV from 1.6% to 3.6% (p = 0.001), and decreased the measured BMD by 20% (t = 12.1, p < 0.001). Studies of two cement phantoms in vitro showed a small downward drift in bone cement BMD giving a measurement error of less than 0.03 g/cm2/year associated with inclusion of cement in femoral ROIs. Changes in pelvic periprosthetic BMD are best detected using a 4-ROI model. Analysis of femoral ROI is more precise without exclusion of cement although an awareness of its effect on the measurement of the BMD is needed.     

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.