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.     

Changes of femoral periprosthetic bone mineral density 6 years after treatment with alendronate following total hip arthroplasty

Earlier osteodensitometric results of femoral periprosthetic bone showed that postoperative antiresorptive treatment with alendronate following total hip arthroplasty (THA) reduces the periprosthetic bone loss that commonly occurs in the first months after surgery. However, whether alendronate can prevent periprosthetic bone loss over the long term, or if bone loss occurs after discontinuing alendronate is unknown. Femoral periprosthetic bone mineral density (BMD) was assessed in 49 patients 6 years after cementless total hip arthroplasty using dual energy X‐ray absorptiometry. Twenty‐nine patients were treated postoperatively with alendronate and 20 control patients received no treatment. All patients were followed up at 12 months after surgery in a prospective randomized study. The bone mineral density was evaluated in 7 regions of interest according to the Gruen protocol. Six years after total hip arthroplasty, no significant changes were detected in femoral periprosthetic BMD when compared with results at 1 year, and the bone loss in patients with postoperative alendronate treatment was still significantly less than those without treatment. These results suggest that the prevention of femoral periprosthetic bone loss following THA achieved by postoperative antiresorptive treatment with alendronate is of long‐standing effect, and further bone loss does not occur after the first postoperative year. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:183–188, 2009     

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.     

Bone mineral density and biochemical markers of bone turnover in aseptic loosening after total hip arthroplasty.

The aims of this study were to determine whether subjects with aseptic loosening after total hip arthroplasty (THA) have regional differences in periprosthetic bone mineral density (BMD) and systemic biochemical markers of bone turnover compared to subjects with successful implants.Proximal femoral and pelvic BMD were measured by dual energy X-ray absorptiometry and bone turnover markers were assayed in 49 subjects 12.6+/-4.3 (mean+/-SD) years after cemented THA. Femoral BMD was lower in Gruen zones 2, 5, 6, and 7 in subjects with a loose femoral implant (n=17) compared to those (n=32) with fixed femoral implants (P<0.05 all comparisons). This BMD difference was greatest (-31%, P=0.02) in the proximal and medial region of the femur. Subjects with femoral loosening had higher levels of the bone resorption marker N-telopeptides of type-I collagen (P=0.02) than those with a fixed femoral implant. No differences in pelvic BMD or bone turnover markers were found between subjects with loose (n=18) versus fixed (n=31) pelvic implants.This study suggests that failure of femoral components after cemented THA is associated with region-specific decreases in BMD and an increase in urinary excretion of N-telopeptide cross-links of type-I collagen. These surrogate outcome markers may be of value in monitoring response to antiresorptive therapies used to treat periprosthetic osteolysis, although the diagnosis of aseptic loosening remains clinical and radiological.     

Effect of pamidronate on bone turnover and implant migration after total hip arthroplasty: a randomized trial.

In this trial we studied the effect of pamidronate on periprosthetic bone turnover and pelvic implant migration over 2 years after hybrid total hip arthroplasty (THA). Twenty-two patients received 90 mg of pamidronate and 22 received placebo at randomization 5 days after surgery. Rapid periprosthetic bone loss occurred in the placebo group over the first 6 months and was accompanied by transient increases in biochemical markers of bone turnover. Partial recovery in bone mass occurred in most regions after this period. No recovery of bone mass occurred at the femoral calcar or the medial wall of the acetabulum. Femoral calcar bone loss at 2 years was strongly predicted by acute biomarker changes at week 6. Pamidronate therapy reduced femoral bone loss in the region of the femoral calcar (P = 0.01), but did not affect pelvic bone loss. Pamidronate therapy also inhibited the transient rise in biochemical markers of bone turnover during this period. Pamidronate therapy did not affect acetabular cup migration. Cup migration was inversely related to subject age, but unrelated to initial post-operative bone mineral density, or subsequent bone loss. In summary, early periprosthetic bone loss is associated with a transient expansion of the bone remodeling space. Bisphosphonate therapy reduces femoral calcar bone loss and bone turnover after THA, but did not influence cup migration in this study. Acute changes in biochemical markers predict femoral periprosthetic bone loss.     

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.     

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.     

Risedronate reduces postoperative bone resorption after cementless total hip arthroplasty

Summary Forty-three patients who had undergone cementless THA were randomly assigned to receive no osteoactive drug or oral risedronate for 6 months. Postoperative decrease of BMD in the risedronate group was significantly lower than that seen in the control group in zones 1, 2, 3, 6, and 7. Introduction Proximal bone resorption around the femoral stem often has been observed after total hip arthroplasty (THA), could lead to late stem loosening. We previously reported the efficacy of etidronate on periprosthetic bone resorption after cementless THA. Recently risedronate is suggested to be effective for the prevention and treatment of for osteoporosis. The purpose of the present study was to evaluate the effects of risedronate on periprosthetic bone loss after cementless THA. Methods Forty-three patients who had undergone cementless THA were randomly assigned to receive no osteoactive drug (21 patients) or oral risedronate 2.5 mg/day (22 patients) for 6 months. Three patients were eliminated from the risedronate group because of dyspepsia. Periprosthetic bone mineral density (BMD) in seven regions of interest based on the zones of Gruen et al. was measured with dual energy X-ray absorptiometry at 3 weeks and 6 months postoperatively. Results At 6 months after surgery, postoperative decrease of BMD in the risedronate group was significantly lower than that seen in the control group in zones 1, 2, 3, 6, and 7 (p < 0.05, p < 0.01, p < 0.01, p < 0.05, and p < 0.05, respectively). Conclusion These outcomes suggested that risedronate might reduce the periprosthetic bone resorption after cementless THA.     

Changes in bone mass and bone turnover following tibial shaft fracture

Introduction: Bone loss occurs in the regional bone following tibial shaft fracture. An earlier cross-sectional study showed that measurements made at the metaphyseal region of the tibia using peripheral quantitative computed tomography (pQCT) and the ultradistal region of the tibia using dual-energy X-ray absorptiometry (DXA) were the most responsive at monitoring this bone loss. Biochemical markers of bone turnover enable us to assess the activity of bone formation and resorption during fracture healing. The aim of this longitudinal study was to determine the pattern and distribution of bone loss and bone turnover following a tibial shaft fracture treated with either plaster cast or intramedullary nail. Methods: Eighteen subjects underwent bone mass measurements using DXA at the tibia and hip and quantitative ultrasound (QUS) at the tibia and calcaneus of both limbs at 2 weeks, 8 weeks, 12 weeks and 24 weeks following fracture, with hip and tibia DXA measurements also performed at 52 weeks. Nine of the patients treated with plaster cast had pQCT measurements at the tibia at 24 weeks. We measured three bone formation markers, bone alkaline phosphatase (bone ALP), osteocalcin (OC) and procollagen type 1 N-terminal peptide (PINP), a marker of bone resorption, serum C-telopeptides of type 1 collagen (β-CTX) and a marker of collagen III turnover, procollagen type III N-terminal peptide (PIIINP) at 1 day, 3 days and 7 days and at 2, 4, 8, 12, 16 and 24 weeks following fracture. The greatest bone losses were observed at the ultradistal region of the tibia using DXA (28%, p <0.001) and the metaphyseal region of the tibia using pQCT (26–31%, p <0.001) at 24 weeks. In the hip, the greatest loss was in the trochanter region at 24 weeks (10%, p <0.001). The greatest loss at the calcaneus measured using QUS was for broadband ultrasound attenuation (BUA) measured using CUBA Clinical at 24 weeks (13%, p =0.01). Results: At 1 year, there was a small recovery in bone loss (ultradistal tibia DXA, 20%, p <0.01; trochanter DXA 9%, p <0.001). Bone turnover increased following fracture (PINP +72±21%, p <0.0001, bone ALP +199±22%, p =0.004, β-CTX +105±23%, p <0.0001, all at 24 weeks). There was a smaller +33±10% increase in osteocalcin at 24 weeks. PIIINP concentration peaked at week 8 (+57±9%, p <0.0001). The bone resorption marker β-CTX showed an earlier rise (week 2, 139±33%) than the bone formation markers. Conclusions: We conclude that: (1) bone loss following tibial shaft fracture occurs both proximal and distal to the fracture; (2) the decreased BMD is largest for trabecular bone in the tibia with similar measurements using DXA and pQCT; (3) there is limited recovery of bone lost at the hip and tibia at 1 year; (4) tibial speed of sound (SOS) demonstrated a greater decrease than calcaneal SOS when comparing z -scores; (5) BUA is the QUS variable that shows the biggest decrease of bone mass at the calcaneus; (6) increase in bone turnover occurs following fracture with an earlier increase in bone resorption markers and a later rise in bone formation markers.     

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.     

The effectiveness of mono or combined osteoporosis drug therapy against bone mineral density loss around femoral implants after total hip arthroplasty

Several previous studies have reported that bone mineral density (BMD) loss around femoral implants is a common outcome, particularly in the proximal femur, after total hip arthroplasty (THA). The purpose of this study was to investigate the effectiveness of alendronate monotherapy and combined therapy using alendronate and alfacalcidol for BMD preservation around femoral implants after primary THA. This study series included 60 patients who were classified into monotherapy (alendronate alone) (n = 18), combined-therapy (alendronate and alfacalcidol) (n = 20) or non-medication (n = 22) groups. The periprosthetic BMD and profile of the biochemical markers such as bone-specific alkaline phosphatase and serum N-terminal telopeptides of type-1 collagen (NT_X) were measured at 1, 12, 24 and 48 weeks after surgery. The BMD values in the region of the calcar of monotherapy and combined-therapy patients were maintained and were significantly higher than those of non-medication patients at each measurement period. The plasma levels of NT_X in the monotherapy and combined-therapy groups were found to be significantly lower than those in the non-medication group at each measurement period. In conclusion, the monotherapy and combined-therapy regimens significantly prevent periprosthetic BMD loss around femoral implants, most notably in the calcar, compared to no medication.     

The short-term changes of bone mineral metabolism following bone marrow transplantation

Organ transplantation is now the treatment of choice for many patients with life-threatening chronic diseases. A new set of side effects unique to these groups of patients has become recognized, and bone disease is one of these complications. However, little is known about the effects of myeloablative treatment followed by bone marrow transplantation (BMT) on bone mineral metabolism. We have prospectively investigated 31 patients undergoing BMT for hematologic diseases. Serum concentrations of calcium, phosphorus, creatinine, gonadotropins, sex hormones, and the biochemical markers of bone turnover were measured. The samples were collected before BMT and 1, 2, 3, 4, and 12 weeks, 6 months, and 1 year after BMT. Bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry before BMT and 1 year after BMT. The serum carboxy-terminal cross-linked telopeptide of type I collagen increased progressively until 4 weeks after BMT. Thereafter, it began to decrease and reached basal values after 1 year. Serum osteocalcin decreased progressively until 3 weeks after BMT. After that, it increased and reached basal values after 3 months. No distinct differences were observed in the serum biochemical turnover markers between males and females, or between patients who received total body irradiation and those who did not. One year after BMT, lumbar spine BMD had decreased by 2.2%, and total proximal femoral BMD had decreased by 6.2%. Eighty-six percent of the women (12/14) went into a menopausal state immediately after BMT. This was caused by high gonadotropin levels and low estradiol levels. In contrast, gonadotropin levels and testosterone levels did not change significantly in the male patients after BMT. In conclusion, the rapid impairment of bone formation and the increase in bone resorption, as shown by the biochemical markers in this study, might play a role in post-BMT bone loss.     

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.

     

The effect of pregnancy on bone density and bone turnover.

During pregnancy, the mother adapts to meet the calcium demands of the fetus. The effect of this adaptation on the maternal skeleton is not fully understood. Our objectives were to evaluate changes in bone mineral density (BMD) and bone turnover during pregnancy. We studied 16 women longitudinally, with baseline measurements before pregnancy; then at 16, 26, and 36 weeks of pregnancy; and postpartum. We measured total-body BMD and biochemical markers of bone resorption (urinary pyridinium crosslinks and telopeptides of type I collagen) and bone formation (serum bone alkaline phosphatase, propeptides of type I procollagen [PINP] and osteocalcin). We also measured parathyroid hormone (PTH), insulin-like growth factor I (IGF-I), and human placental lactogen. Postpartum, BMD increased in the arms (2.8%, P < 0.01) and legs (1.9%, P < 0.01) but decreased in the pelvis (-3.2%, P < 0.05) and spine (-4.6%, P < 0.01) compared with prepregnancy values. All biochemical markers, with the exception of osteocalcin concentration, increased during pregnancy. The change in IGF-I at 36 weeks was related to the change in biochemical markers (e.g., PINP, r = 0.72, P = 0.002). Pregnancy is a high-bone-turnover state. IGF-I levels may be an important determinant of bone turnover during pregnancy. Elevated bone turnover may explain trabecular bone loss during pregnancy.     

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.     

Predictive value of a preoperative biochemical bone marker in relation to bone remodeling after cementless total hip arthroplasty.

To identify the factors predicting proximal bone resorption of the femur after cementless total hip arthroplasty (THA), we studied 24 postmenopausal women with osteoarthritis. Periprosthetic bone mineral density (BMD) measurements of the seven Gruen zones were determined with dual-energy X-ray absorptiometry at 3 wk, 6, 12, and 18 mo after operation. The greatest decrease in BMD (13.2%) was found in zone 7 at 18 mo. At 18 mo, preoperative serum bone alkaline phosphatase was associated univariately with BMD loss in zones 1 (r = 0.407, p = 0.048) and 7 (r = 0.543, p = 0.006) and urinary N-telopeptide cross-linked collagen type I (NTX) was associated univariately with that in zone 7 (r = 0.520, p = 0.009). Patient age correlated with BMD loss in zone 7 (r = 0.425, p = 0.039). Multiple regression analysis identified a significant relationship between the BMD loss and patient age and NTX in zone 7 at 18 mo (r2 = 0.422, p = 0.001). We conclude that preoperative bone markers are significant predictors of bone remodeling after THA with the particular implants used in our study.     

Rapid and robust response of biochemical markers of bone formation to teriparatide therapy

Teriparatide, a parathyroid hormone analogue, is a potent anabolic treatment for postmenopausal osteoporosis. Studies have shown that teriparatide induces large increases in biochemical markers of bone formation after 1 month of therapy followed by a delayed increase in bone resorption markers.The aims of this study were to (1) describe changes in bone turnover markers during 28 days of treatment with teriparatide; (2) identify the earliest time point by which most subjects showed a biochemical response to teriparatide; (3) identify potential biomarkers of positive bone response; (4) describe changes in bone turnover markers 4 weeks after stopping teriparatide.We recruited 15 osteopenic postmenopausal women, ages 55–69 (mean 62) years. All received 20 μg teriparatide subcutaneously for 28 days. Serum levels of the bone formation markers type I collagen N-terminal propeptide (PINP), type I collagen C-terminal propeptide (PICP), osteocalcin (OC), bone alkaline phosphatase (bone ALP), and the bone resorption markers crosslinked C-telopeptide of type I collagen (Sβ-CTX), crosslinked N-telopeptide of type I collagen (S-NTX) and tartrate-resistant acid phosphatase type 5b (TRACP5b) were measured on 11 occasions: three times before dosing (baseline) and on days 3, 7, 10, 14, 19, 24 and 28 and at day 56 (i.e., 28 days after stopping teriparatide ).During the first 2 days of teriparatide treatment, PINP levels increased rapidly, by 8.2% (90% confidence interval (CI) 6.9%, 9.5%) and continued to increase until the end of treatment to 110.8%. PICP and OC showed a similar, but less pronounced, pattern. All three markers increased by at least 75% at day 28. A small, transient decrease in bone resorption markers occurred over the same period. Following cessation of treatment, concentrations of bone formation markers decreased to within 20% of baseline values by day 56.In conclusion, the bone formation markers PINP, PICP and OC show a rapid and robust increase in response to teriparatide, which is noticeable during the first week of therapy. PINP is the most responsive marker. These findings have important implications for monitoring patients treated with teriparatide and may also inform the design of studies of new anabolic agents for osteoporosis.     

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。     

Periprosthetic bone remodelling of two types of uncemented femoral implant with proximal hydroxyapatite coating: a 3-year follow-up study addressing the influence of prosthesis design and preoperative bone density on periprosthetic bone loss

Periprosthetic bone loss is a major cause of concern in patients undergoing total hip arthroplasty (THA). Further studies are required to identify the factors determining the pattern of bone remodelling following THA and obtain improvements in the design and durability of prostheses. In this study, we monitored periprosthetic bone loss around two different types of hydroxyapatite coated femoral implant over a 3-year period to evaluate their design and investigate the relationship with the preoperative bone mineral density (BMD) at the spine, hip and forearm. Sixty patients (35 F, 25 M, mean age 63 years, range 46–75 years) undergoing THA were randomised to either the Anatomic Benoist Girard (ABG) or Mallory-Head (MH) femoral stem. Preoperative dual-energy X-ray absorptiometry (DXA) scans were acquired of the posteroanterior (PA) and lateral lumbar spine, the contralateral hip and the non-dominant forearm. Postoperative DXA scans were performed to measure periprosthetic BMD at 10 days (treated as baseline), 6 weeks, and 3, 6, 12, 24 and 36 months after THA using a standard Gruen zone analysis. Results were expressed as the percentage change from baseline and the data examined for the differences in bone loss between the different Gruen zones, between the ABG and MH stems, and the relationship with preoperative BMD. A total of 50 patients (24 ABG, 26 MH) completed the study. Three months after THA there was a statistically significant BMD decrease in every Gruen zone that varied between 5.6% and 13.8% for the ABG prosthesis and between 3.8% and 8.7% for the MH prosthesis. Subsequently, in most zones BMD reached a plateau or showed a small recovery. However, BMD continued to fall in Gruen zones 1 and 7 in ABG patients and Gruen zone 1 in MH patients. Bone loss was less in every Gruen zone in MH patients compared with ABG with the largest difference (10%, P=0.018) in Gruen zone 7. Highly significant relationships were found between periprosthetic bone loss and preoperative BMD measured at the PA spine (P<0.001), total hip (P=0.004) and total distal radius (P<0.001). This study showed differences between two different designs of hydroxyapatite-coated implant that confirmed that prosthesis design influences periprosthetic bone loss. The study also showed that patients bone density measured at the spine, hip or forearm at the time of operation was a major factor influencing bone loss around the femoral stem.     

Effects of discontinuation as well as intervention of cyclic therapy with etidronate on bone remodeling after cementless total hip arthroplasty

We previously reported the effects of cyclic therapy with etidronate (CTE) on periprosthetic bone mineral density (BMD) after cementless total hip arthroplasty (THA). This study aimed to evaluate the effects of withdrawal and intervention of CTE after cementless THA. The control group consisted of 24 patients without osteoactive drugs. Sixteen patients continued on CTE (i.e., 400 mg/day oral etidronate for 2 weeks followed by 12 weeks of 500 mg/day calcium lactate, repeated every 14 weeks) for the first 12 months followed by no treatment for 18 months (early-etidronate group). Fifteen patients received no treatment for the first 18 months followed by CTE for 12 months (late-etidronate group). Periprosthetic BMD in seven regions of interest based on the zones of Gruen et al. was measured with dual energy X-ray absorptiometry at 3 weeks, 6, 12, 18, 24, and 30 months postoperatively. At 12 months after operation (off therapy point in the early-etidronate group), postoperative decreases of BMD in the early-etidronate group were significantly smaller than those in the control group in zones 1, 2, 5, 6, and 7 and those in the late-etidronate group in zones 1, 5, 6, and 7 (P < 0.05 for each). In the early-etidronate group, significant decreases in BMD were found during months 12-30 (off therapy period) after withdrawal of CTE in zones 1 and 7 (P < 0.05 for each). In the late-etidronate group, BMD increased significantly in zones 4 and 6 (P < 0.05 for each) during months 18-30 (on therapy period) after intervention trial, while in the controls, BMD decreased significantly in zone 3 (P < 0.05) over this period. At the final follow-up (30 months), BMD loss in zone 7 was significantly less in the early-etidronate group than in the other groups (P < 0.05). BMD changes in the early-etidronate group and late-etidronate group were associated with changes in biochemical bone markers.