Discordance in femoral neck bone density in subjects with unilateral hip osteoarthritis

Side-to-side differences in hip bone mineral density in patients with unilateral hip osteoarthritis

BACKGROUND

Accurately evaluating bone mineral density (BMD) in patients with unilateral hip osteoarthritis (OA) is crucial for diagnosing osteoporosis and selecting implants for hip arthroplasty. Our goal was to measure the BMD differences between sides, examine contributing factors, and identify the optimal side for BMD assessment in these patients.

METHODS

We analyzed 108 women with unilateral hip OA. Bilateral hip BMD was assessed automatically through quantitative CT (QCT) utilizing a validated, deep-learning-based approach. We evaluated BMD variations between the OA and healthy hips across total, neck, and distal regions. To determine their contributions, we analyzed factors, including patient demographics, Crowe classification, Bombelli classification, knee OA status, hip functional score, and gluteal muscle volume and density. Furthermore, we examined how side-to-side BMD differences influenced osteoporosis diagnosis using T-scores based on QCT.

RESULTS

The average BMD on the OA side was 6.9 % lower in the total region, 14.5 % higher in the neck region, and 9.4 % lower in the distal region than on the healthy side. Contributing factors to the reduced BMD in the OA hip included younger age, Bombelli classification (atrophic type), and significant gluteal muscle atrophy. Diagnoses from the OA side revealed lower sensitivity (61 %) than those from the healthy side (88 %).

CONCLUSIONS

Analysis on one side alone yields a more precise osteoporosis diagnosis from the healthy side. Nonetheless, bilateral BMD assessment remains crucial, particularly in younger individuals and those with atrophic OA types. Although based on QCT, our findings support bilateral analysis by dual-energy X-ray absorptiometry for these patients.

Discordance Between Spine-Hip and Paretic-Nonparetic Hip Bone Mineral Density in Hemiplegic Stroke Patients: A Multicenter Retrospective Study

OBJECTIVE

To identify the prevalence and factors associated with T-score discordance between the spine and hip, as well as between the paretic and non-paretic hips in hemiplegic stroke patients, this study investigated bone mineral density (BMD) patterns. Bone loss predominantly affects the paretic hip after a stroke, and typical clinical assessments using dual-energy X-ray absorptiometry (DXA) that scan the lumbar spine (LS) and a single hip may overlook an osteoporosis diagnosis. This oversight could potentially lead to suboptimal treatment for stroke patients.

METHODS

This study was a multicenter retrospective analysis of 540 patients admitted for stroke rehabilitation between October 2014 and February 2022, who underwent DXA of LS and bilateral hips.

RESULTS

The prevalence rates of concordance, low LS discordance, and low hip discordance between the LS and hips were 48.2%, 12.2%, and 39.6%, respectively. The discordance rate between bilateral hips was 17.0%. The paretic side had significantly lower total hip T-scores than the non-paretic side (p<0.001). Notably low paretic hip discordance was more prevalent during the chronic phase. DXA scans of the LS and both hips revealed a 0.7%-0.9% higher major discordance compared to LS and single hip DXA scans. The multivariate analysis revealed a significant correlation between a low paretic hip discordance and cognitive impairment (adjusted odds ratio 0.071, 95% confidence interval 0.931-1.003, p<0.05).

CONCLUSION

Since stroke survivors are at high risk for hip fractures, comprehensive BMD assessments, which include LS and bilateral hips, should be considered for post-stroke osteoporosis care to enhance diagnostic accuracy and timely treatment.

Accounting for Surgical Confounding Factors Affecting Dual-Energy X-ray Absorptiometry in a Large Clinical Trial

Joint replacements are among the most common orthopedic procedures performed in the U.S. and will continue to increase with the aging population. It is therefore necessary to account for these and other confounding factors, such as breast implants, when performing dual-energy X-ray absorptiometry (DXA) measurements. Whole-body DXA scans were performed in 771 participants (men ≥50 yr and women ≥55 yr) to assess bone mineral density (BMD) and body composition (fat and lean mass). In the DXA scan analyses of participants with internal metal, these affected regions of interest were replaced with measures from the unaffected, contralateral side, consistent with recommendations of the International Society for Clinical Densitometry. T-scores and Z-scores were recalculated using default sex and ethnicity-matched databases. We also explored effects of breast implants on bone density and body composition analyses. Approximately 13.1% of participants had internal metal artifacts at baseline. Replacing metal artifacts with the unaffected, contralateral side decreased the whole-body BMD by an average of 8.1% (SEM 0.84%; n = 67). In participants with unilateral hip (n = 17) and knee replacements (n = 20), BMD was decreased by an average of 14.1% (SEM 1.7%) and 11.2% (SEM 1.1%), respectively. Fat and lean mass were not significantly affected by metal artifacts, as differences between values with and without metal were within 1%. Two participants had bilateral breast implants, and in a separate trial, one participant had a unilateral breast implant. Bone mineral content (BMC) in the region with the breast implant was 5.8 times higher than the contralateral side, and whole-body BMC was increased by 4.7%. Metal artifacts and breast implants can confound DXA whole-body bone but not fat and lean results. It is therefore important in clinical studies to account for these factors to detect physiologically relevant differences in bone measures.

Increased development of radiographic hip osteoarthritis in individuals with high bone mass: a prospective cohort study

BACKGROUND

Individuals with high bone mass (HBM) have a greater odds of prevalent radiographic hip osteoarthritis (OA), reflecting an association with bone-forming OA sub-phenotypes (e.g. osteophytosis, subchondral sclerosis). As the role of bone mineral density (BMD) in hip OA progression is unclear, we aimed to determine if individuals with HBM have increased incidence and/or progression of bone-forming OA sub-phenotypes.

METHODS

We analysed an adult cohort with and without HBM (L1 and/or total hip BMD Z-score > + 3.2) with pelvic radiographs collected at baseline and 8-year follow-up. Sub-phenotypes were graded using the OARSI atlas. Superior/inferior acetabular/femoral osteophyte and medial/superior joint space narrowing (JSN) grades were summed and Δosteophyte and ΔJSN derived. Pain and functional limitations were quantified using the WOMAC questionnaire. Associations between HBM status and change in OA sub-phenotypes were determined using multivariable linear/logistic regression, adjusting for age, sex, height, total body fat mass, follow-up time and baseline sub-phenotype grade. Generalised estimating equations accounted for individual-level clustering.

RESULTS

Of 136 individuals, 62% had HBM at baseline, 72% were female and mean (SD) age was 59 (10) years. HBM was positively associated with both Δosteophytes and ΔJSN (adjusted mean grade differences between individuals with and without HBM β_osteophyte = 0.30 [0.01, 0.58], p = 0.019 and β_JSN = 0.10 [0.01, 0.18], p = 0.019). Incident subchondral sclerosis was rare. HBM individuals had higher WOMAC hip functional limitation scores (β = 8.3 [0.7, 15.98], p = 0.032).

CONCLUSIONS

HBM is associated with the worsening of hip osteophytes and JSN over an average of 8 years, as well as increased hip pain and functional limitation.

Defining disease progression in Chinese mainland people: Association between bone mineral density and knee osteoarthritis

Objective

To evaluate change in bone mineral density (BMD) during development of knee osteoarthritis (OA) in elderly Chinese community residents. Further, to monitor disease progression by recording speed of sound (SOS), one parameter of BMD provided by quantitative ultrasound measurement.

Methods

A total of 4173 community residents of the Chinese mainland were organized to complete questionnaires and relevant measurements, including anthropometry, radiology and quantitative ultrasound (QUS). SOS measurements of the distal radius were acquired using QUS measurements. The Kellgren-Lawrence (KL) grade of knee OA was evaluated by two experienced radiographers using X-rays. Finally, a general linear models analysis was performed to determine potential relationships. Further, the area under the receiver operating characteristic curve (ROC AUC) was applied to assess the distinction model.

Results

The SOS score in the OA group was significantly lower than that in the control group (p ​< ​0.001). However, after adjustment for age and body mass index (BMI), no significant difference was observed in the male population (p ​＝ ​0.841), while a significantly lower SOS score presented in knee OA participants in the female population (p ​＝ ​0.033). A turning point in SOS scores, from increasing to decreasing trends, occurred around KL grade 2; the SOS score gradually increased with progression in participants from KL grades 0 to 2, whereas the SOS score presented a significant decrease in participants with KL grades 3 and 4. The AUC for the model to distinguish OA progression was 0.891.

Conclusion

There was a non-linear and stage-specific association between SOS score and knee OA, which presented a positive relationship in early stages, but a negative relationship in advanced stages. A decline of SOS score in knee OA patients in early stages should alert clinicians to the possibility of disease progression.

The Translational potential of this article

In the present study, the relationship between OA and BMD had established by SOS. The results suggested that close monitoring of SOS in elderly Chinese communities residents with knee OA could alert disease progression involvement by an easily accessible method, and help early referral to orthopedist consultation for further examination and treatment.

Baseline characteristics of participants in the VITamin D and OmegA-3 TriaL (VITAL): Effects on Bone Structure and Architecture

Vitamin D supplements are often used to benefit skeletal health, although data on effects of daily high-dose vitamin D alone on bone density and structure are lacking. The ongoing VITamin D and OmegA-3 TriaL (VITAL) is a double-blind, randomized, placebo-controlled trial testing effects of high-dose supplemental vitamin D3 (cholecalciferol; 2000 IU/day) and/or omega-3 fatty acids (FAs; 1 g/day) for the primary prevention of cancer and cardiovascular disease. The study has a mean treatment period of 5 years among 25,874 U.S. men ≥50 years and women ≥55 years old from all 50 states. The ancillary study, VITAL: Effects on Bone Structure and Architecture, is testing effects of vitamin D3 and/or omega-3 FAs on musculoskeletal outcomes and body composition in a subcohort of 771 participants. At in-person visits at the Harvard Catalyst Clinical and Translational Science Center (CTSC), participants completed bone density/architecture, body composition, and physical performance assessments at baseline and two-year follow-up. Baseline characteristics were evenly distributed among treatment groups, suggesting that any uninvestigated confounders will be evenly distributed; sex differences were also analyzed. Future analyses of the two-year follow-up visits will elucidate whether daily high-dose, supplemental vitamin D3 and/or omega-3 FAs improve musculoskeletal outcomes, helping to advance clinical and public health recommendations.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01747447.

Is the cortical thickness index a valid parameter to assess bone mineral density in geriatric patients with hip fractures?

INTRODUCTION

Reduced bone quality is a common problem during surgical fixation of geriatric hip fractures. The cortical thickness index (CTI) was proposed to assess the bone mineral density (BMD) of the proximal femur on the basis of plain X-rays. The purpose of this study was to evaluate the inter- and intraobserver reliability of the CTI and to investigate correlation between CTI and BMD in geriatric patients.

METHODS

60 patients (20 pertrochanteric fractures, 20 femoral neck fractures, 20 without fractures) were included. All patients had ap and lateral hip X-rays and measurement of BMD by Dual Energy X-ray Absorptiometry at different areas of the hip. The ap and lateral CTI was measured twice by four blinded observers and correlation between mean CTI and BMD was calculated.

RESULTS

Mean ap CTI was 0.52 and mean lateral CTI was 0.45. Inter- and intraobserver reliability was good for ap CTI (ICC 0.71; 0.79) and lateral CTI (ICC 0.65; 0.69). A significant correlation between CTI and overall BMD was found in patients without fractures (r = 0.74; r = 0.67). No significant correlation between CTI and overall BMD was found in patients with proximal femoral fractures.

CONCLUSION

The CTI has sufficient reliability for the use in daily practice. It showed significant correlation with BMD in patients without hip fractures. In patients with proximal femoral fractures, no correlation between CTI and BMD was found. We do not recommend the CTI as parameter to assess the BMD of the proximal femur in geriatric patients with hip fractures.

The relationship between osteoarthritis and osteoporosis

The relationship between osteoarthritis (OA) and osteoporosis (OP), the two most common skeletal disorders related to aging, is controversial. Previous studies suggest that OA is inversely related to OP when studied cross-sectionally and systematically. However, there are differences in the results depending on the parameter used to define OA. The purpose of this review is to analyze and summarize the literature, and derive possible answers to three key questions along with a brief introduction on underlying mechanisms: (1) Is OA correlated to a high bone mineral density (BMD)? (2) Does OA influence the progression of OP or osteoporotic fractures? (3) Does high BMD affect the incidence and progression of OA? A review of the literature suggests that OA is inversely related to OP in general when studied cross-sectionally and systematically. However, when analyzed in individual bones, the BMD of the appendicular skeleton in OA-affected joints may decrease, particularly in the upper extremities. On whether OA influences bone loss or osteoporotic fractures, differences are observed according to the affected joints. The risk for osteoporotic fracture does not seem to decrease despite a high BMD in patients with OA, probably due to postural instability and muscle strength. Low BMD at the lumbar spine is associated with a lower incidence of knee OA although it does not arrest the progression of knee OA.

Tibial subchondral bone mineral density: sources of variability and reproducibility

OBJECTIVES

It has been shown that subchondral bone mineral density (sBMD) measurement may be a relevant parameter of osteoarthritis (OA) progression. However, factors implicating the reproducibility and contributing to the variability of the measurement have not been fully described. Thus, the aim of this study was to explore the reproducibility of sBMD by Dual energy X-ray Absorptiometry (DXA) and to further examine its sources of variability.

METHODS

In this study, short-term, intra and inter-observer reproducibility of sBMD was examined on knee images obtained on DXA scans. The influence of software (lumbar spine and forearm modes), knee positioning (flexion or extension), site and size of regions of interest (ROI) and use of rice, on both lateral and medial tibial sBMD, were assessed. Root mean square coefficient of variation (RMS CV) and least significant changes (LSC) were calculated.

RESULTS

The short-term precision of sBMD ranged between 2.24% and 5.12% for RMS CV and between 0.053 and 0.135 g/cm(2) for LSC. Good intra-observer precision was found for knee flexion conditions whatever the software used (RMS CV ranging from 0.43 to 1.41%). The reproducibility was dependant from the ROI size (the ROI including joint space exhibiting better precision results than ROI including solely the subchondral plate). For a constant size of the ROI, the precision results were site-dependant. Inter-observer RMS CV results ranged from 0.59 to 5.01% according to ROI and software used. For the specific task of monitoring medial sBMD in the ROI including solely subchondral plate, forearm flexion condition produced the highest intra-observer and short-term precision (respectively RMS CV: 0.45% and 2.77%; LSC: 0.013 and 0.080 g/cm(2)).

CONCLUSION

Taking account into the excellent precision of the sBMD measurements expressed as RMS CV with the protocol proposed in the present study, clinical application of these measurements might be envisaged.

Bone density is higher in cam-type femoroacetabular impingement deformities compared to normal subchondral bone

OBJECTIVE

Cam-type femoroacetabular impingement (FAI) deformities have been associated with early osteoarthritic degeneration of the hip. Degeneration depends on many factors such as joint morphology and dynamics of motion. Bone mineral density (BMD) appears to be a manifestation of the above, and may be a potentiator. Thus the goal of this study was to assess subchondral BMD of cam deformities in symptomatic and asymptomatic FAI subjects, and to compare to normal controls.

METHODS

Subjects undergoing surgical correction of a symptomatic cam-type deformity were recruited ("Surgical"). Asymptomatic volunteers were also recruited and classified as normal ("Control") or having a deformity ("Bump") based on their alpha angle measurement. All subjects (n = 12 per group) underwent computed tomography (CT) with a calibration phantom. BMD was determined in volumes of interest around the femoral head and neck to a depth of 5 mm. BMD was compared between groups in each section using spine BMD as a covariate.

RESULTS

No differences were seen between groups in the peripheral bearing surface. The Bump group exhibited higher BMD than Controls within the head/neck junction (P < 0.05). When compared to normal subchondral bone in the peripheral level of Controls, BMD in the deformity was up to 78% higher in Bump subjects and up to 47% higher in Surgical subjects (P < 0.05).

CONCLUSION

Subchondral BMD of cam deformities is higher than that of normal subchondral bone in the peripheral region of the femoral head, regardless of symptom status. The expected increased subchondral stiffness may increase contact stresses in the joint tissues leading to accelerated degeneration.

High bone density and bone health

The aim of this paper is to review the main aspects related to high bone density (HBD) as well as to discuss the physiologic mechanisms involved in bone health. There are still no well-defined criteria for identification of individuals with HBD and there are few studies on the topic. Most studies demonstrate that overweight, male gender, black ethnic background, physical activity, calcium and fluoride intake and use of medications such as statins and thiazide diuretics play a relevant and positive role on bone mineral density. Moreover, it is known that individuals with certain diseases such as obesity, diabetes, estrogen receptor-positive breast or endometrial cancer have greater bone density than healthy individuals, as well as athletes having higher bone density than non-athletes does not necessarily mean that they have healthy bones. A better understanding of risk and protective factors may help in the management of patients with bone frailty and have applicability in the treatment and in the prevention of osteoporosis, especially intervening on non-modifiable risk factors.

Underestimated fracture probability in patients with unilateral hip osteoarthritis as calculated by FRAX

Osteoporosis (OP) and osteoarthritis (OA) are age-related diseases often considered to be mutually exclusive. We previously found that 25% of women with advanced OA had occult OP and that femoral neck (FN) bone mineral density (BMD) T-scores were significantly higher for osteoarthritic vs contralateral hips. The FRAX calculator incorporates clinical risk factors and FN BMD T-score to estimate 10-yr total fracture probability and hip fracture probability. In 35 women and men aged 41 yr or older with unilateral hip OA scheduled for hip replacement, we tested whether FRAX fracture probability is underestimated when using data for the OA rather than the contralateral hip. There were between-hip differences for FN BMD T-score (p<0.0001), total fracture probability (p =0.0004), and hip fracture probability (p =0.0009). Use of FN BMD T-scores resulted in OP treatment recommendations for 0% and 11% of subjects compared with 11% and 17% for total fracture probability and hip fracture probability, respectively. In 6-11% of subjects in this series, the FRAX calculator underestimated fracture probability with data for the OA hip. With the increased use of FRAX in clinical use, these data suggest that measurement of BMD at the contralateral hip may yield higher calculated FRAX total and hip fracture probabilities.

Vitamin D metabolism and action in human bone marrow stromal cells

Vitamin D metabolites are important effectors of bone and mineral homeostasis. Extrarenal conversion of 25-hydroxyvitamin D (25OHD) to the biologically active form of vitamin D, 1 alpha,25-dihydroxyvitamin D [1,25(OH)(2)D] is catalyzed in several cell types by the 1 alpha-hydroxylase (CYP27B1), but little is known about the expression or regulation of CYP27B1 in human bones. We examined whether human bone marrow stromal cells (hMSCs, also known as mesenchymal stem cells) participate in vitamin D metabolism and whether vitamin D hydroxylases in hMSCs are influenced by the vitamin D status of the individual from whom the hMSCs were obtained. We also investigated the effects of vitamin D metabolites on osteoblast differentiation and the role of IGF-I in the regulation of CYP27B1. In a series of 27 subjects, vitamin D hydroxylases in hMSCs were expressed at different levels and were correlated with serum 25OHD, 1,25(OH)(2)D, and PTH. In vitro treatment with 25OHD up-regulated CYP27B1 and IGF-I in hMSCs; IGF-I also up-regulated CY27B1 expression and stimulated osteoblast differentiation. When hydroxylation of 25OHD was blocked by ketoconazole, a cytochrome P450 inhibitor, 25OHD was no longer able to induce CYP27B1 expression. In summary, these findings show that human bone marrow stromal cells have the molecular machinery both to metabolize and respond to vitamin D. We propose that circulating 25OHD, by virtue of its local conversion to 1,25(OH)(2)D catalyzed by basal CYP27B1 in hMSCs, amplifies vitamin D signaling through IGF-I up-regulation, which in turn induces CYP27B1 in a feed-forward mechanism to potentiate osteoblast differentiation initiated by IGF-I.