Age-related changes of bone mineral density in human calcaneus, talus, and scaphoid bone

Exploring Age-Related Variations in Carpal Bone Volume: Implications for Clinical Practice and Anatomical Understanding

BACKGROUND

Clinically recognizing the changes in carpal bone volumes and understanding their implications in predicting osteoarthritis (OA) is crucial in clinical practice This study aimed to explore age-related differences in carpal bone volumes across genders, leveraging computed tomography (CT) wrist scans to create 3D surface models of these bones.

METHODS

Carpal bone volumes were calculated using the 3D Slicer software from CT scans obtained from Frankston Hospital and additional datasets from Brown and Auckland Universities. The data were statistically processed using Stata V13. Double-sided P-values < .05 were considered statistically significant. The study was conducted in accordance with the ethical standards laid out in the Declaration of Helsinki.

RESULTS

A total of 181 patients were analyzed, and 48% of whom were female. A statistically significant positive Spearman correlation (rho = 0.37-0.611, P <.05) was observed between increasing age and the volume of all surveyed carpal bones (scaphoid, lunate, triquetrum, pisiform, hamate, capitate, and trapezium) across genders. Intrauser and interuser reliabilities for 3D Slicer-generated volumes of trapezium and pisiform bones were statistically significant, with Interclass Correlation Coefficient (ICC) values of 0.86 and 0.95, respectively.

CONCLUSION

Trapezial volumes increase with age, potentially due to the presence of OA and consequent osteophyte formation. This pattern is more prevalent among older individuals and women. However, the positive correlation between carpal bone volume and age was consistent across all carpal bones and both genders, regardless of OA presence. These findings suggest that carpal bone volume may naturally increase with age, independent of OA-related changes.

LEVEL OF EVIDENCE

III, cohort study.

The epidemiology of scaphoid fractures in Sweden: a nationwide registry study

The epidemiology of scaphoid fractures has been described in limited populations, and incidence reports have been inconsistent. We investigated the nationwide incidence of scaphoid fractures by evaluating data on 34,377 patients in the Swedish National Patient Register for the years 2006-2015 regarding diagnosis, age, sex and treatment. The data were validated in 300 random patients, and incidence rates were adjusted accordingly. Forty-one per cent of the initially diagnosed fractures were false positives. The adjusted true fracture incidence rate was 22 per 100,000 person-years. During the decade studied incidence rates decreased in younger men and increased in middle-aged women. The incidence of surgical treatment vs. non-operative treatment did not change over time. Men were treated surgically more often than women (6% vs. 3%) and had a greater risk for nonunion (3% vs. 1%).

Biomechanical evaluation of subtalar fusion: the influence of screw configuration and placement

Common surgical procedures for subtalar fusion include joint resection, autologous bone grafting, and osteosynthesis with screws in a parallel screw configuration. Although fusion is a routine procedure, the reported rates of nonunion have been high. The present study assessed different screw configurations in terms of their rotational and bending stability in an artificial bone model and cadaver bone. Arthrodesis was always performed with 2 screws. Three different screw configurations were tested: parallel, counter-parallel, and a delta configuration. Two different screw designs were used: a cannulated, partially threaded screw (6.5-mm and 8.0-mm diameter) and a solid screw with a different thread design. Eight experimental groups were investigated as pilot studies in artificial bones and then 3 groups in cadaver bones. The parameters were the primary stiffness and deflection of the construct for loads simulating the internal-external rotation and supination-pronation. Delta positioning of the screws resulted in the greatest biomechanical stiffness and the lowest degrees of deflection of the arthrodesis in the artificial bones and cadaver bones. Increasing the screw diameter from 6.5 to 8.0 mm resulted in no additional stability of the arthrodesis in the artificial bones. The results of the present study have indicated that the delta configuration for arthrodesis results in the greatest construct stiffness and lower relative deflection between the talus and calcaneus in the positions tested.

Effect of implantation accuracy on ankle contact mechanics with a metallic focal resurfacing implant

BACKGROUND

Talar osteochondral defects can lead to joint degeneration. Focal resurfacing with a metallic implant has shown promise in other joints. We studied the effect of implantation accuracy on ankle contact mechanics after focal resurfacing of a defect in the talar dome.

METHODS

Static loading of seven cadaver ankles was performed before and after creation of a 15-mm-diameter osteochondral defect on the talar dome, and joint contact stresses were measured. The defect was then resurfaced with a metallic implant, with use of a custom implant-bone interface fixture that allowed fine control (in 0.25-mm steps) of implantation height. Stress measurements were repeated at heights of -0.5 to +0.5 mm relative to an as-implanted reference. Finite element analysis was used to determine the effect of implant height, post axis rotation, and valgus/varus tilt over a motion duty cycle.

RESULTS

With the untreated defect, there was a 20% reduction in contact area and a 40% increase in peak contact stress, as well as a shift in the location of the most highly loaded region, as compared with the values in the intact condition. Resurfacing led to recovery of 90% of the contact area that had been measured in the intact specimen, but the peak contact stresses remained elevated. With the implant 0.25 mm proud, peak contact stress was 220% of that in the intact specimen. The results of the finite element analyses agreed closely with those of the experiments and additionally showed substantial variations in defect influences on contact stresses across the motion arc. Talar internal/external rotations also differed for the unfilled defect. Focal implant resurfacing substantially restored kinematics but did not restore the stresses to the levels in the intact specimens.

CONCLUSIONS

Focal resurfacing with a metallic implant appears to have the potential to restore normal joint mechanics in ankles with a large talar osteochondral defect. However, contact stresses were found to be highly sensitive to implant positioning.

Bone density comparison of selected carpal and tarsal bones: validation for their use in compression fracture fixation studies of scaphoid screws

INTRODUCTION

To determine if trabecular, total and cortical bone densities of the capitate, navicular, cuboid, and first cuneiform were equivalent to those of the scaphoid, such that these bones could be used in place of the scaphoid in evaluating new headless scaphoid compression screws.

METHODS

Fifty scaphoids, capitates, naviculars, cuboids, and first cuneiforms were harvested from fresh frozen cadavers. The trabecular, total and cortical bone densities were measured using pQCT technology and statistically compared.

RESULTS

A paired t comparison between paired scaphoids and capitates showed no difference between the trabecular bone densities. However, their total bone and cortical densities were found to be different. An independent measures ANOVA comparison of the five bones, showed no significant difference in mean trabecular density between the capitates, naviculars and first cuneiforms when compared to the scaphoids. However, the mean total and cortical densities of the first cuneiforms were less than the scaphoids and the mean trabecular, total and cortical bone densities of the cuboids were all less than the scaphoids.

DISCUSSION

Compression fracture fixation studies of headless compression screws could be conducted using the capitate, navicular, and first cuneiform as models of the scaphoid when the supply of scaphoids is limited.