Visualization and quantification of the degenerative pattern of the distal tibia and fibula in unilateral varus ankle osteoarthritis

A novel classification of lateral malleolus morphological characteristics based on three-dimensional computed tomography reconstruction

BACKGROUND

The study was to establish a novel classification of the morphological characteristics of fibula anterior-inferior margin (FAIM), which was reported in few studies.

METHODS

The 501 images with three-dimensional computed tomography (3D CT) reconstruction were reviewed retrospectively. The width, height, thickness, long axis, short axis, and lateral malleolus angle were measured.

RESULTS

The FAIM was divided into Angular, Flat, and Arc. The Flat has no distinct fibular obscure tubercles (FOT). The short axis of Angular and Arc were more significant than the Flat (P < 0. 05). The height of left was larger than the right, but short axis was less than it (P < 0.05). The height and short axis of males were larger than the females (P < 0.05).

CONCLUSIONS

A novel classification (the Angular, Flat and Arc) of FAIM was identified based on lateral malleolus morphology, and it suggested that not all have obvious FOT.

LEVEL OF EVIDENCE

Level Ⅲ, retrospective study.

Morphological features of the non-affected side of the hindfoot in patients with unilateral varus ankle osteoarthritis

BACKGROUND

The innate shape characteristics of the hindfoot bones alter the loading conditions of the foot and thus may be associated with an increased risk of developing varus ankle osteoarthritis (OA). This study aimed to clarify the innate morphological patterns of the hindfoot bones that may be associated with ankle OA by analyzing the differences between the bone morphology of the non-affected side of patients with unilateral varus ankle OA and that of healthy participants.

METHODS

In this case-control study, computed tomography images were used to develop three-dimensional models of three hindfoot bones (distal tibia with fibula, talus, and calcaneus) from 23 non-affected sides of patients with radiography-diagnosed unilateral ankle OA and 22 healthy control participants. Anatomical and sliding landmarks were placed on the surface of each bone, and the principal components (PCs) of shape variation among specimens were independently calculated for each bone, preserving homology between individuals. The PC modes representing 5% or more of the overall variation were statistically compared between the ankle OA and control groups.

RESULTS

Significant differences were identified between the OA and control groups in the fifth PC mode for the tibia with fibula (proportion of variance, 5.1%; p =.025), fifth PC mode for the talus (6.7%, p =.031), and third PC mode for the calcaneus (7.4%, p =.001). The hindfoot bones of the participants who developed ankle OA had the following innate morphological characteristics: the lateral malleolar articular surface of the fibula was shifted superiorly, tibial plafond was enlarged posteroinferiorly, posterior width of the talar trochlea was narrower, talonavicular articular surface of the talus was oriented more frontally, anterior-middle talocalcaneal articular surfaces of the talus were more medially shifted and those of the calcaneus were flatter, calcaneal sustentaculum tali was less protruding, and lateral plantar process of the calcaneus was more superiorly positioned.

CONCLUSIONS

These distinctive morphological alterations may increase the incidence and progression of varus ankle OA through aberrant anterior translation, internal rotation, and varus tilting of the talus.

Systematic review of computed tomography parameters used for the assessment of subchondral bone in osteoarthritis

OBJECTIVE

To systematically review the published parameters for the assessment of subchondral bone in human osteoarthritis (OA) using computed tomography (CT) and gain an overview of current practices and standards.

DESIGN

A literature search of Medline, Embase and Cochrane Library databases was performed with search strategies tailored to each database (search from 2010 to January 2023). The search results were screened independently by two reviewers against pre-determined inclusion and exclusion criteria. Studies were deemed eligible if conducted in vivo/ex vivo in human adults (>18 years) using any type of CT to assess subchondral bone in OA. Extracted data from eligible studies were compiled in a qualitative summary and formal narrative synthesis.

RESULTS

This analysis included 202 studies. Four groups of CT modalities were identified to have been used for subchondral bone assessment in OA across nine anatomical locations. Subchondral bone parameters measuring similar features of OA were combined in six categories: (i) microstructure, (ii) bone adaptation, (iii) gross morphology (iv) mineralisation, (v) joint space, and (vi) mechanical properties.

CONCLUSIONS

Clinically meaningful parameter categories were identified as well as categories with the potential to become relevant in the clinical field. Furthermore, we stress the importance of quantification of parameters to improve their sensitivity and reliability for the evaluation of OA disease progression and the need for standardised measurement methods to improve their clinical value.

Total Ankle Replacement in Cavovarus Deformity: How Far Can We Go?

Because of the good functional results and satisfactory implant survival achieved with modern models, total ankle replacement (TAR) has become a legitimate alternative to ankle fusion. However, alignment and balance are mandatory for implant survival. Satisfactory results can be achieved in patients with significant preoperative deformity if alignment and balance were obtained. If not, a staged procedure involving deformity correction and secondary TAR is possible. The authors describe the principal aspects of this concept and illustrate their current approach to TAR in cavovarus deformity.