地舒单抗对绝经后骨质疏松性股骨颈骨折全髋关节置换术后股骨近端假体周围骨密度的影响

目的:研究地舒单抗对绝经后骨质疏松性股骨颈骨折患者全髋关节置换术后(total hip arthroplasty,THA)股骨近端假体周围骨密度的影响。方法:选取2020年10月至2021年10月绝经后女性骨质疏松性股骨颈骨折行THA术后54例,治疗组25例接受地舒单抗治疗,年龄(74.3±6.2)岁;对照组29例未接受地舒单抗治疗,年龄(75.2±4.8)岁。术后1周及3、6及12个月各个时间点,通过双能X线骨密度仪(DEXA型)测定股骨近端假体周围骨密度,并在不同时间点测量骨转换各项指标。结果:术后3、6及12个月对照组的抗酒石酸酸性磷酸酶(tartrate resistant acid phosphatase,TRACP-5b)高于治疗组(P<0.05);对照组术后12个月骨特异性碱性磷酸酶(bone-specific alkaline phosphatase,BALP)高于治疗组(P<0.05)。两组患者Gruen 1、7区的骨密度在术后3、6及12个月较术后1周(基线)均下降(P<0.05);对照组Gruen 7区术后各时间点比较,差异有统计学意义(P<0.05);治疗组各时间点比较,差异无统计学意义(P>0.05)。两组术后3个月Gruen 1、7区比较,差异无统计学意义(P>0.05);术后6个月Gruen 1、7区和术后12个月Gruen 1、7区,治疗组骨密度均明显高于对照组(P<0.05)。两组术后3个月Gruen 1、7区骨密度下降百分比比较,差异无统计学意义(P>0.05)。对照组术后6个月Gruen 1、7区,术后12个月Gruen 1、7区骨密度下降百分比明显高于治疗组(P<0.05)。提示在使用地舒单抗6个月后,即可降低骨密度丢失幅度,并且该效应可达至术后12个月。结论:绝经后骨质疏松性股骨颈骨折患者在THA术后,使用地舒单抗可减少股骨近端假体周围骨密度丢失,有效抑制骨吸收。     

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。     

Effect of robotic milling on periprosthetic bone remodeling.

The ROBODOC system has provided better fit and fill of the stem and less destruction of the bony architecture than with manual surgery. These benefits might affect femoral periprosthetic bone remodeling. We evaluated the effects of robotic milling in cementless total hip arthroplasty (THA) in a longitudinal 24-month follow-up study using dual energy X-ray absorptiometry (DEXA) and plain radiographs of 29 patients (31 hips) after ROBODOC THA and 24 patients (27 hips) after manual THA with the same stem design. To minimize the influence of other factors on bone remodeling, only female osteoarthritis patients, who had no drugs that might affect bone metabolism were enrolled. Significantly less bone loss occurred at the proximal periprosthetic areas in the ROBODOC group. In zone 1, the decrease was 15.5 versus 29.9% using conventional rasping; in zone 7, the loss was 17.0% with ROBODOC compared to 30.5% with conventional rasping (p < 0.05). On radiographs, endosteal spot welds in the proximal medial portion were more pronounced in the ROBODOC group (48 vs. 11% in the conventional group, p < 0.05). Our results suggest that robotic milling is effective in facilitating proximal load transfer around the femoral component and minimizing bone loss after cementless THA.     

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.     

Cyclic therapy with etidronate has a therapeutic effect against local osteoporosis after cementless total hip arthroplasty

Proximal bone resorption around the femoral stem is one of the major complications of cementless total hip arthroplasty (THA). The potential complications resulting from proximal bone resorption include femoral fracture and late stem loosening. The purpose of this study was to evaluate the effects of cyclic therapy with etidronate on periprosthetic bone mineral density (BMD) after cementless THA. Fifty-two patients who had undergone cementless THA were randomized for this study. Group A consisted of 30 hips in 29 patients without osteoactive drugs. Group B consisted of 23 hips in 23 patients with cyclic therapy with etidronate (i.e., 400 mg/day of oral etidronate for 2 weeks followed by 12 weeks of 500 mg/day of calcium lactate and repeated every 14 weeks), one of whom was excluded from the study because of side effects attributed to the drug. Periprosthetic BMD in seven regions of interest based on the zones of Gruen et al. (Clin. Orthop. 141 (1979), 17-27) was measured with dual energy X-ray absorptiometry (DXA) at 3 weeks, 6 months, and 12 months postoperatively. The postoperative decreases of BMD in group B were significantly lower than those in group A in zones 1 and 7 (P < 0.05 and P < 0.05, respectively) at 6 months and in zones 1, 2, 6, and 7 (P < 0.05, P < 0.05, P < 0.05, and P < 0.001, respectively) at 12 months. The BMD change appeared to be stabilized at 6 months in all zones in group B, while in group A there was a progressive decrease of average BMD (6.1%) in zone 7 between 6 months and 12 months. These findings suggested that cyclic therapy with etidronate may help to reduce the resorptive changes in the proximal part of the femur after cementless THA. Further follow-up study with larger populations will be required to define the potential efficacy of intermittent cyclic etidronate therapy on postoperative bone loss.     

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     

Monitoring of periprosthetic BMD after uncemented total hip arthroplasty with dual-energy X-ray absorptiometry--a 3-year follow-up study.

Insertion of a metallic implant into the femur changes bone loading conditions and results in remodeling of femoral bone. To quantify changes in bone mass after uncemented total hip arthroplasty (THA), we monitored femoral bone with dual-energy X-ray absorptiometry (DXA). The periprosthetic bone mineral density (BMD) was measured with Lunar DPX densitometry in seven Gruen zones and the total periprosthetic area at scheduled time intervals in 22 patients during a 3-year follow-up. BMD decreased significantly almost in all Gruen zones during the first 3 months, ranging from 3.4% to 14.4% (p < 0.05 top < 0.001). At the end of the first year, the most remarkable decrease in BMD was found in the calcar (zone 7; -22.9%). During the second postoperative year, a slight restoration of periprosthetic bone mass was recorded. During the third year, no significant changes in BMD were found. The preoperative BMD was the only factor that was significantly related to the periprosthetic bone loss. Clearly, the early periprosthetic bone loss noticed during the 3 months after THA is caused by mainly limited weight bearing to the operated hip and stress shielding. We suggest that the restoration of bone mass is a sign of successful osteointegration between bone and metallic implant. DXA is a suitable tool to follow the bone response to prosthetization and will increase our knowledge on the behavior of bone after THA.     

Denosumab Prevents Early Periprosthetic Bone Loss After Uncemented Total Hip Arthroplasty: Results from a Randomized Placebo-Controlled Clinical Trial

Implant loosening is the most common indication for revision surgery after total hip arthroplasty (THA). Although bone resorption around the implants plays a pivotal role in the pathophysiology of loosening, it is unknown whether potent early inhibition of osteoclasts could mitigate this process and thus reduce the need for revision surgery. We performed a randomized, double-blind, placebo-controlled phase 2 trial in 64 patients aged 35 to 65 years with unilateral osteoarthritis of the hip. They underwent surgery with an uncemented THA and were randomized to either two subcutaneous doses of denosumab (n = 32) or placebo (n = 32) given 1 to 3 days and 6 months after surgery. Patients were followed for 24 months. Primary outcome was periprosthetic bone mineral density (BMD) of the hip at 12 months as measured by dual-energy X-ray absorptiometry (DXA). In addition, [¹⁸F] sodium fluoride positron emission tomography/CT (F-PET) was performed in half of the patients for analysis of periprosthetic standardized uptake value (SUV). Analyses were made according to intention-to-treat principles. The trial was registered at ClinicalTrials.gov 2011-001481-18, NCT01630941. Denosumab potently inhibited early periprosthetic bone loss. After 12 months, BMD in the denosumab group was 32% (95% confidence interval [CI] 22–44) higher in Gruen zone 7 and 11% (95% CI 8–15) higher in zones 1 to 7. After 24 months, the difference in BMD between groups had decreased to 15% (95% CI 4–27) in zone 7 and 4% (95% CI 0–8) in zones 1 to 7. In both groups, SUV increased after surgery, but the increase was less pronounced in the denosumab group. Biochemical markers of bone metabolism decreased in the denosumab group in the first 12 months, but a rebound effect with marker concentrations above baseline was observed after 24 months. Denosumab potently prevents early periprosthetic bone loss after uncemented THA; however, the effect diminishes after discontinuation of treatment. Further research is needed to determine whether this bone loss will prove to be of clinical importance and, if so, whether the positive effect observed in this study could be preserved by either prolonged treatment with denosumab or additional antiresorptive treatment. © 2019 American Society for Bone and Mineral Research. © 2019 American Society for Bone and Mineral Research.     

Changes in bone mineral density (BMD) around the cemented Exeter stem: A prospective study in 18 women with 5 years follow‐up

Background and purpose?THA changes the pattern of strain distribution in the proximal femur. We quantified the changes in BMD for 5 years after insertion of the cemented Exeter stem in women.

Methods?18 women aged 55–79 years, undergoing unilateral THA with the cemented Exeter stem, were included in the study. The BMD was measured in 7 femoral regions of interest according to Gruen, and the contralateral hip and spine using dual‐energy X‐ray absorptiometry postoperatively, at 18 and at 60 months of follow‐up. Results were tested using Wilcoxon matched‐pairs signed‐rank test.

Results?During the first 18 months, a significant decrease in BMD was seen in zones 2, 3, 6, and 7. No significant changes were seen in zones 4 and 5, in the contralateral hip, or at the spine. In zone 1, there was a small but significant rise in BMD. From 18 to 60 months, we observed a statistically significant rise in BMD in all zones except 4 and 7. Despite this, the total periprosthetic BMD decreased during the follow‐up relative to the immediate postoperative situation. There was no significant reduction in BMD in the contralateral hip. In the spine, we observed a significant rise in BMD.

Interpretation?18 months after THA, BMD had decreased in Gruen zones 2, 3, 6, and 7. The bone loss was similar to that seen after other implants and appears to be related to the changes in stress pattern within the proximal femur. At 5 years, BMD had increased again in these zones. It remained lower than baseline, however.     

Bone loss around failed femoral implant measured by dual-energy X-ray absorptiometry

Periprosthetic bone mineral density (BMD) and its changes after primary total hip arthroplasty (THA) have been studied extensively, but quantitative data on BMD around loosened prostheses are still lacking. In this study, using dual-energy X-ray absorptiometry (DXA), we determined periprosthetic BMD in 19 patients with failed primary THA. There was a decrease in BMD (8.8%–25.5%) in every Gruen zone as compared with the patient's non-operated (control) side. Although the bone loss was most significant in the proximal femur, as in primary THA, the pattern of bone loss around the failed THA differred from the typical remodeling seen after successful THA. We suggest that quantitation of bone mass around the failed femoral stem is possible. Remarkable generalized bone loss around the stem is associated with a loosened prosthesis. Received: November 12, 1999 / Accepted: December 24, 1999     

Alendronate prevents femoral periprosthetic bone loss following total hip arthroplasty: prospective randomized double-blind study.

Following total hip arthroplasty (THA), femoral periprosthetic bone undergoes a remodeling process that results in bone loss in its proximal regions that may compromise the long-term outcome of THA. Periprosthetic bone loss mainly occurs during the first postoperative months. The question is whether a postoperative treatment with alendronate is effective in reducing periprosthetic bone loss and which doses and duration of treatment are required. In a 12-month prospective, randomized double-blind study, 51 patients undergoing cementless THA were treated postoperatively either with a daily dose of 20 mg alendronate for 2 months and 10 mg for 2 months thereafter (group I), with 20 mg of alendronate for 2 months and 10 mg for 4 months thereafter (group II), or treated with placebo (group III). Proximal femoral bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry (DEXA) and serum biochemical markers of bone turnover bone specific alkaline phosphatase, osteocalcin, and C-terminal telopeptides (CTX-I) were assayed. Six months of alendronate treatment significantly reduced (p<0.001) bone loss in proximal medial region (-10%) compared with placebo (-26%). All biochemical markers of bone turnover were suppressed by alendronate. These data suggest that alendronate administered for the first 6 postoperative months following THA was effective in preventing early periprosthetic bone loss.     

Bone remodeling around stable uncemented titanium stems during the second decade after total hip arthroplasty: a DXA study at 12 and 17?years

Summary  

In a cohort study, bone mineral density (BMD) around uncemented femoral components after total hip arthroplasty (THA) was evaluated. The results suggest that there are no clinically relevant changes in overall periprosthetic BMD in the second decade. However, continuous remodeling with limited proximal bone loss (stress-shielding) occurs, predominantly in female patients.     

Proximal femoral bone mineral density after resurfacing total hip arthroplasty and after standard stem-type cementless total hip arthroplasty, both having similar neck preservation and the same articulation type

To examine whether the Freeman cementless total hip arthroplasty (THA), with femoral neck preservation and a large metal head, can prevent stress shielding in a manner similar to resurfacing THA, we compared femoral bone mineral density (BMD) change in 10 resurfacing THA patients (group A) and 16 cementless THA patients (group B). Six and twelve months postoperatively, the mean BMD ratio in zone 1 was significantly higher in group A (97% +/- 10%, 95% +/- 11%) than in group B (79% +/- 15%, 77% +/- 20%); at 12 months, the mean BMD ratio in zone 7 was significantly higher in group A (104% +/- 15%) than in group B (84% +/- 21%). The cementless THA might not be a substitute for the resurfacing THA with respect to prevention of proximal femoral bone loss at the femoral neck, although it may prevent some major complications after resurfacing THA such as neck fracture and avascular necrosis of the femoral head.     

Clinical efficacy of bisphosphonates and monoclonal antibodies on bone mineral density following skeletal fractures

BackgroundBisphosphonates and monoclonal antibodies are drugs primarily developed to inhibit osteoclast-mediated bone resorption and are used to treat an array of skeletal pathologies. Their use is aimed at increasing bone health and therefore reducing fracture risks. The aim of this study was to evaluate the effectiveness of bone protection therapy on improving bone mineral density (BMD) in patients following a fracture.MethodsInclusion criteria consisted of patients who sustained a skeletal fracture and were subsequently commenced on bone protection therapy. Dual-energy X-ray Absorptiometry (DEXA) scans were performed at baseline and following a consented period of drug therapy. Bone health data included T-Scores, Z-Scores, FRAX Major, FRAX Hip and BMD. The clinical effectiveness of four bisphosphonates (alendronate, risedronate, pamidronate and zoledronate) and one monoclonal antibody (denosumab) were evaluated.ResultsA total of 100 patients were included in the study. Overall, bone protection therapy significantly improved Z-score Hip, Z-score Spine, T-score Spine and BMD Spine (p < 0.05). There was a marked difference between drug therapies. Denosumab and zoledronate were associated with the greatest treatment effect size. Alendronate only improved Z-score Spine and Z-score Hip (p < 0.05). Pamidronate and risedronate did not demonstrate any statistically significant improvement across any DEXA parameter.ConclusionOverall, bisphosphonates/monoclonal antibodies confer beneficial effects on bone health as measured by DEXA scans in patients following skeletal fractures. However, the magnitude of improvement varies among the commonly used drugs. Alendronate, zoledronate and denosumab were associated with greatest therapeutic benefit. Bone protection therapy did not improve fracture risk of patients (FRAX scores).     

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。     

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.     

Revision total hip arthroplasty in juvenile chronic arthritis: 17 revisions in 11 patients followed for 4–12 years

Background Revision total hip arthroplasty (THA) in patients with juvenile chronic arthritis (JCA) is complicated by the young age of the patient, poor bone stock and small physical proportions. We report the complications and outcome of a prospective series of 17 revision THAs in Charnley class C JCA patients.

Methods 15 acetabular components and 10 femoral components were revised. 13 cementless cups, 2 reconstruction/roof rings and cemented cups, and 4 cemented and 6 cementless femoral stems were implanted. 2 proximal femoral allografts and 1 strut allograft were used. Age at revision was 32 (21–53) years. Follow-up averaged 7 (4–12) years.

Results 2 patients with cemented femoral stems developed loosening, osteolysis and fracture. Both were successfully revised to long-stem cementless implants with strut/proximal femoral allografts. 1 loose, worn cementless cup with osteolysis was revised. 1 patient with a peri-operative infection and late acetabular fracture had a loose, non-revised cementless cup. 1 case of sciatic nerve palsy occurred after revision using a reconstruction ring. 1 late infection necessitated resection arthroplasty. Harris hip scores improved from 53 (34–85) to 76 (47–96).

Interpretation Revision THA in JCA has a substantial complication rate, even in experienced hands. The problem of obtaining long-term stable fixation, osteolysis, and replenishment of lost bone stock are major difficulties.     

A Role for Modern Primary Cementless Femoral Stems in Revision Hip Arthroplasty

BackgroundIn revision total hip arthroplasty (THA) cases with preserved femoral metaphyseal bone, tapered proximally porous-coated “primary” femoral stems may be an option. The objective of this study was to compare outcomes of patients with Paprosky I or II femoral bone loss undergoing revision THA with either a primary metaphyseal-engaging cementless stem or a revision diaphyseal-engaging stem.MethodsThis was a retrospective analysis of 70 patients with Paprosky I or II femoral bone loss who underwent femoral revision. 35 patients who were revised using a primary cementless femoral stem were compared with 35 patients who underwent femoral revision using a revision diaphyseal-engaging stem. The groups were similar regarding age, gender, body mass index, and American Society of Anesthesiologists. Clinical and radiographic outcomes and complications were compared over an average follow-up of 2.9 years (SD 1.4).ResultsRevision THA was most commonly performed for periprosthetic joint infection (N = 27, 38.6%). The groups were similar with regards to Paprosky femoral classification (P = .56), length of stay (P = .68), discharge disposition (P = .461), operative time (P = .20), and complications (P = .164). There were no significant differences between primary and revision femoral stem subsidence (0.12 vs. 0.75 mm, P = .18), leg length discrepancy (2.3 vs. 4.05 mm, P = .37), and Hip Disability and Osteoarthritis Outcome Score Jr (73.1 [SD 21.1] vs. 62.8 [SD 21.7], P = .088). No patient underwent additional revision surgery involving the femoral component.ConclusionUse of modern primary cementless femoral stems is a viable option for revision hip arthroplasty in the setting of preserved proximal femoral metaphyseal bone. Outcomes are not inferior to those of revision stems and offer potential benefits.     

Progressive femoral cortical and cancellous bone density loss after uncemented tapered-design stem fixation

Background Aseptic implant loosening and periprosthetic bone loss are major problems after total hip arthroplasty (THA). We present an in vivo method of computed tomography (CT) assisted osteodensitometry after THA that differentiates between cortical and cancellous bone density (BD) and area around the femoral component.

Method Cortical and cancellous periprosthetic femoral BD (mg CaHA/mL), area (mm²) and contact area between the prothesis and cortical bone were determined prospectively in 31 patients 10 days, 1 year, and 6 years after uncemented THA (mean age at implantation: 55 years) using CT-osteodensitometry.

Results 6 years postoperatively, cancellous BD had decreased by as much as 41% and cortical BD by up to 27% at the metaphyseal portion of the femur; this decrease was progressive between the 1-year and 6-year examinations. Mild cortical hypertrophy was observed along the entire length of the diaphysis. No statistically significant changes in cortical BD were observed along the diaphysis of the stem.

Interpretation Periprosthetic CT-assisted osteodensitometry has the technical ability to discriminate between cortical and cancellous bone structures with respect to strain-adapted remodeling. Continuous loss of cortical and cancellous BD at the femoral metaphysis, a homeostatic cortical strain configuration, and mild cortical hypertrophy along the diaphysis suggest a diaphyseal fixation of the implanted stem. CT-assisted osteodensitometry has the potential to become an effective instrument for quality control in THA by means of in vivo determination of periprosthetic BD, which may be a causal factor in implant loosening after THA.     

The Influence of Dorr Type and Femoral Fixation on Outcomes Following Total Hip Arthroplasty for Acute Femoral Neck Fractures: A Multicenter Study

BackgroundThe American Academy of Orthopaedic Surgeons guidelines report moderate evidence for cementing femoral stems for hip fractures, mainly derived from hemiarthroplasty literature. This is the first large, nonregistry study examining the influence of femoral fixation, implant type, patient characteristics, and radiographic factors on outcomes after total hip arthroplasty (THA) for acute femoral neck fractures.MethodsA multicenter retrospective study was performed of 709 THA cases (199 cemented, 510 cementless) for femoral neck fractures from 2006 to 2020 at three large academic institutions. Demographics, perioperative characteristics, and radiographs were reviewed. Kaplan-Meier survivorship curves were generated for multiple outcomes. Univariate and multivariate analyses were performed with P ≤ .05 denoting significance.ResultsCementless stems had a higher all-cause aseptic femoral revision rate (5.1 versus 0.5%, P = .002) and periprosthetic femoral fracture rate (4.3 versus 0%, P = .001). Each successive Dorr type had a higher fracture rate with cementless implants: 2.3%, 3.7%, and 15.9% in Dorr A, B, and C, respectively (P < .001). Logistic regression analyses confirmed that cementless stems (P = .02) and Dorr C bone (P = .001) are associated with periprosthetic fractures; collared implants and prophylactic cables did not protect against fractures. There was no difference in rates of dislocation, septic revision, or mortality between groups.ConclusionCementless stems during THA for femoral neck fractures have a higher aseptic femoral revision rate, specifically for periprosthetic fractures. Dorr C bone was particularly prone with an alarmingly high fracture rate. All fractures occurred in cementless cases, suggesting that cemented stems may minimize this complication.Level of EvidenceIII.