Does the bone mineral density measured on a preoperative CT scan before total hip arthroplasty reflect the bone's mechanical properties?

Preoperative computer tomography scans can accurately evaluate tibial bone mineral density for selecting bone fixation in total knee arthroplasty

INTRODUCTION/OBJECTIVE

The mechanical quality of bone at the proximal tibia is an important factor for the success of cementless total knee arthroplasty (TKA). The purpose of this study was to evaluate the relationship between preoperative bone mineral density (BMD) at the tibial resection level (tibial BMD) using computed tomography (CT) and intraoperative cancellous bone durability (ICBD) in TKA.

METHODS

All consecutive cemented and cementless TKAs performed by a single surgeon between April 2024 and October 2024 were evaluated. All patients were examined preoperatively for tibial BMD via CT, hip BMD via dual-energy X-ray absorptiometry. A block of cancellous bone with a diameter of 10 ​mm and a height of 10 ​mm was harvested at the center of the tibia. The fixation method was selected intraoperatively according to the macroscopically evaluated bone quality. Using a pusher tension gauge and a metal measure, the force required to compress the harvested bone from 10 ​mm to 5 ​mm was measured and defined as ICBD. Pearson product-moment correlations were calculated to assess the relationships between tibial and hip BMD and ICBD.

RESULTS

A consecutive series of 74 TKAs were included. There were 50 cementless fixations and 24 cemented fixations. Tibial BMD, hip BMD and mean ICBD were significantly greater in the cementless group than in the cemented group (tibial BMD: 70.3 ± 26.2 vs 37.5 ± 14.4, and hip BMD: 87.3 ± 11.8 vs 65.6 ± 10.5, ICBD: 85.6 ± 35.6 vs 49.8 ± 18.1, respectively, P < 0.01). The cut-off value of tibial BMD indicating a cementless prosthesis was 46.4 HA/cm3. There was a very strong correlation between tibial BMD and ICBD (r = 0.88, P < 0.01) and a strong correlation between hip BMD and ICBD(r = 0.62, P < 0.01).

CONCLUSION

This study is the first report to focus on the relationships between CT-based tibial BMD and the actual bone quality of the proximal tibia . Assessment of bone quality via CT is accurate, relatively simple, and potentially useful for determining whether cementless fixation in TKA is indicated. For cementless fixation, 46.4 HA/cm3 and 55.7 N were found as tibial BMD and ICBD cut-off values.

LEVEL OF EVIDENCE

Retrospective cohort study, Level Ⅳ.

Validation of mediCAD® software for fully digital preoperative planning of total hip arthroplasty: a retrospective study

INTRODUCTION

The planning step that precedes a total hip arthroplasty (THA) procedure is crucial. Digital planning software programs are being increasingly used, although few studies have reported on the reliability of such tools. Furthermore, no studies have been conducted on the mediCAD® software, despite it being widely used in France. This led us to conduct a retrospective study to: (1) assess the accuracy of this planning software, (2) determine the intra- and inter-rater reliability, (3) determine how obesity affects the accuracy of planning.

HYPOTHESIS

THA planning is accurate and reliable when using the mediCAD® software.

PATIENTS AND METHODS

This was a single center, retrospective study. One hundred one consecutive cases performed by a single experienced surgeon were planned retrospectively by two blinded surgeons on two separate occasions. The acetabular cup was cemented in 90 hips (89%), cementless in 11 hips (11%). A dual mobility cup was used in 21 hips (21%). The femoral stem was cemented in 60 hips (59%). The endpoint was the number of exact plans, defined as the same size as the actual implants. An acceptable match was defined as a difference of one size. The match was unacceptable if the planned and implanted size differed by more than 2 for the acetabular cup or by more than 1 size for the femoral stem. The intra-rater and inter-rater reliability were calculated using the intraclass correlation coefficient (ICC) with 95% confidence intervals (CI).

RESULTS

Exact agreement was found by the first rater for 15 planned acetabular cups (15%) and for 45 planned femoral stems (45%) relative to the implants used. The second rater reached exact agreement for 20 planned acetabular cups (20%) and 50 planned femoral stems (50%). The intra-rater reliability for the acetabular cup was average (ICC = 0.57; 95%CI [0.43-0.69]) and poor (ICC = 0.38 95%CI [0.20-054]) for the 1st and 2nd rater, respectively. The intra-rater reliability for the femoral stem was poor for the 1st rater (ICC = 0.47 95%CI [0.30-0.61]) and the 2nd rater (ICC = 0.45 95%CI [0.29-0.60]). The interobserver reliability was low for the planned acetabular cup (ICC = 0.39 95%CI [0.21-0.54]) and the planned femoral stem (ICC = 0.42 95%CI [0.24-0.57]). Overall, when combining the two raters, exact prediction of the acetabular cup was achieved in 31 hips (19%) in non-obese patients and in 7 hips (21%) in obese patients (p = 0.62).

DISCUSSION

This study found acceptable reliability of the mediCAD® software. Experience level, radiograph magnification affected the planning outcome in this study, but obesity did not. We currently do not have the ability to incorporate a reliable radiological scale for two-dimensional templating. Some surgeons prefer using a CT scan, but this costs more than conventional radiographs and exposes the patient to more radiation. This study shows that the mediCAD® software can provide satisfactory output for the preoperative planning of THA.

LEVEL OF EVIDENCE

III; retrospective, diagnostic, comparative study.

Bone Quality Assessment Before Total Hip Arthroplasty: The Role of Densitometry

Background Total hip arthroplasty (THA) is effective in the treatment of hip osteoarthritis. Radiographic evaluation, standard in THA planning, is sufficient in examining hip anatomy, although it may not precisely assess bone quality. A routinely implemented method in bone quality assessment is densitometry. The technique allows for a measurement of bone mineral density (BMD). Methodology In the study, we included 26 participants who qualified for THA. All the patients were preoperatively examined with radiographs and densitometry of the affected hip. On the preoperative anteroposterior radiograph, we measured the canal-to-calcar isthmus ratio (CC ratio) and the cortical index (CI). Intraoperatively, during the THA procedure, we measured the thickness of the cortical bone and the diameter of the femoral neck in the line of neck resection. Results The examination with Pearson's correlation coefficient revealed that BMD significantly positively correlates with the intraoperatively measured diameter of the femoral neck (r = 0.5, P = 0.009), and with the measured thickness of the cortical bone (r = 0.47, P = 0.015), CI significantly positively correlates with the intraoperatively measured diameter of the femoral neck (r = 0.6, P = 0.001), and with the CC ratio (r = 0.44, P = 0.024), the intraoperatively measured diameter of the femoral neck significantly positively correlates with the intraoperatively measured thickness of the cortical bone (r = 0.59, P = 0.001). All of the other correlations were not statistically significant. Conclusions BMD measurements can be used in THA planning as they positively correlate with intraoperative measurements. The radiological parameters (CC ratio and CI) may not be as precise in bone quality assessment.

Biphasic Bioceramic Obtained from Byproducts of Sugar Beet Processing for Use in Bioactive Coatings and Bone Fillings

This study focuses on developing hydroxyapatite synthesized from a CaCO3-rich byproduct of sugar beet processing called Carbocal® using a hydrothermal reactor. The purpose of this biomaterial is to enhance the osteoinductivity of implantable surfaces and serve as a bone filler, providing a sustainable and economically more affordable alternative. This research involved compositional analysis and micro- and macrostructural physicochemical characterization, complemented with bioactivity and live/dead assays. The biphasic nature of the Carbocal®-derived sample was significant within the context of the bioactivity concept previously proposed in the literature. The bioactivity of the biomaterial was demonstrated through a viability test, where the cell growth was nearly equivalent to that of the positive control. For comparison purposes, the same tests were conducted with two additional samples: hydroxyapatite obtained from CaCO3 and commercial hydroxyapatite. The resulting product of this process is biocompatible and possesses properties similar to natural hydroxyapatite. Consequently, this biomaterial shows potential as a scaffold in tissue engineering and as an adhesive filler to promote bone regeneration within the context of the circular bioeconomy in the geographical area proposed.

Changes in adipose bone marrow and bone morphology in X-linked hypophosphatemic rickets

INTRODUCTION

X-linked hypophosphatemic (XLH) rickets causes significant bone deformities in the lower limbs resulting from a bone mineralization defect. According to Frost's Mechanostat theory, compensatory modeling of the bones takes place during increased mechanical loads. In addition, mechanical stimuli modulate the differentiation of mesenchymal stem cells; common precursors to bone marrow adipocytes and osteoblasts.

HYPOTHESIS

Bone deformities of the lower limbs lead to increased femoral bone mass and decreased fatty infiltration of the bone marrow (FIBM) in children with XLH rickets compared to a control group.

PATIENTS AND METHODS

Eleven children (10.3years [6-17]) with XLH rickets and 22 healthy children (10.2years [5-15.5]) underwent lower limb Magnetic Resonance Imaging. A calculation of FIBM was performed at the mid-femur, as well as a calculation of the total bone cross-sectional area (CSA), the cortical CSA, the anteroposterior and mediolateral axes of the femur, bone marrow and the thickness of the femoral cortices.

RESULTS

Total bone CSA, total cortical CSA and bone marrow CSA were higher in the XLH group than in the control group (p<0.05). The mid-lateral diameters of the femur and bone marrow were more elongated than those of the control group (p<0.001). Only the anterior cortex was thinned in the XLH group (p=0.001), while there was no difference with the control group for the posterior, medial and lateral cortices. The total percentage of FIBM was 72.81% [±3.95] and 77.4% [±5.52] for the XLH and control groups respectively (p<0.001).

DISCUSSION

The increase in bone mass in the XLH population reflects an adaptation of bone tissue to the bone deformities present in this pathology. The decrease in FIBM indicates a lower risk of osteoporosis in the XLH population and may constitute a new monitoring parameter in this pathology.

LEVEL OF STUDY

III; Case-control study.