Changes of density distribution of the subchondral bone plate after supramalleolar osteotomy for valgus ankle osteoarthritis

Analysis of radiologic parameters and clinical outcomes in supramalleolar osteotomy for varus ankle osteoarthritis: A novel method for evaluating ankle alignment

BACKGROUND

Solely relying on the tibial ankle surface (TAS) angle for determining the mechanical ankle axis might be insufficient. We introduce a novel method to determine the distance from the center of the talus to the tibial axis (TTD). This study aimed to investigate the association between clinical outcomes and radiological changes before and after supramalleolar osteotomy (SMO), including TAS angle, talar tilt (TT) angle, tibiotalar surface (TTS) angle and TTD.

METHODS

Seventy patients who received SMO were enrolled. Radiological changes were measured using weight-bearing anteroposterior imaging. The percentage of talar center displacement (TTDP) was calculated as the difference between postoperative and preoperative TTD, divided by talar width (TW). Clinical assessments were performed using the American Orthopedic Foot and Ankle Society ankle-hindfoot (AOFAS) scale. Differences in the aforementioned indicators before and after the operation were analyzed. We defined ΔAOFAS, ΔTAS, ΔTT and ΔTTS as the difference between postoperative and preoperative values.

RESULTS

ΔTTS correlated with ΔAOFAS (r = 0.40, p = 0.008), as did TTDP (r = 0.32, p = 0.035). No correlation was observed between ΔAOFAS and ΔTAS. In the comparison between groups, patients with a TTDP greater than 26.19 exhibited a significantly greater ΔAOFAS. The high intraclass correlation coefficient indicated good reliability of the novel method.

CONCLUSION

Solely relying on the TAS angle for tibial correction was insufficient. We found TTD as a novel method to evaluate mechanical ankle joint axis. TTDP and ΔTTS both positively correlated with ΔAOFAS, indicating the usefulness of these radiologic parameters.

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.

Joint Preserving Surgery for Valgus Ankle Osteoarthritis

Valgus ankle OA is a complex problem with multiple etiologies that can either be isolated or superimposed on top of other medical or musculoskeletal disorders. Proper medical history, physical, and preoperative radiological examinations are crucial in deciding on surgery and planning the surgical approach. JPS, especially the varisating medial closing-wedge SMOT with solid plate fixation, has been consistently associated with good outcomes for patients with valgus ankle OA. To further improve JPS for valgus ankle OA, further clinical and biomechanical studies are required to address the long-term clinical and functional outcomes and complications.

Bone Mineralization Changes in the Subchondral Bone of the Medial Gutter in Chronic Lateral Ankle Instability

BACKGROUND

Chronic ankle instability (CAI) induces osteoarthritis (OA) by inflicting abnormal stresses on the medial gutter. It is important to detect early OA change and to explore factors likely to induce the OA. The purpose of this study was to evaluate subchondral bone change in the medial gutter of CAI using computed tomography (CT) scans.

METHODS

Thirty-five ankles with CAI (CAI group) and 35 ankles without CAI (control group) were included. The region of interest (ROI) in the subchondral bone of the medial gutter on CT axial images was set on the tibia and talus. The Hounsfield unit (HU) in ROIs was measured and corrected by the HU of the fibula in the same slice. HU ratios were compared between the CAI and control groups. In the CAI group, the relationship between the HU ratio and the talar tilt angle (TTA), OA change, and the anterior talofibular ligament (ATFL) remnant quality were analyzed.

RESULTS

The mean HU ratio in the CAI group was significantly higher than that in the control. In the CAI group, HU ratios in ≥10 degrees of TTA were significantly higher than those in <10 degrees. But there was no significant difference in the HU ratios with or without OA change in the medial gutter. A good-quality ATFL remnant showed a low HU ratio compared with that with poor quality.

CONCLUSION

CAI patients exhibited subchondral bone change in the medial gutter, which suggests that the elimination of instability may help to prevent or decrease the development and/or progression of osteoarthritis.

LEVEL OF EVIDENCE

Level III, comparative series.

Bone mineralization changes of the glenoid in shoulders with symptomatic rotator cuff tear

PURPOSE

Computed tomography osteoabsorptiometry (CTO) is a method to analyze the stress distribution in joints by measuring the subchondral bone density. The purpose of this study was to evaluate the bone mineralization changes of the glenoid in shoulders with rotator cuff tears by CTO and to evaluate whether rotator cuff tears are associated with stress changes in the glenoid.

METHODS

In total, 32 patients, who were diagnosed with unilateral rotator cuff tears and underwent arthroscopic rotator cuff repair, were enrolled in this study. They underwent CT scanning of both shoulders pre-operatively and the glenoid was evaluated using CTO. Hounsfield units (HU) in seven areas of the glenoid were compared between the affected and unaffected sides.

RESULTS

The central area of the glenoid on the affected side had significantly lower HU than on the unaffected side among all patients. Focusing on the rotator cuff tear size and the subscapularis tendon, only patients with larger cuff tears or with subscapularis tendon tears showed significantly lower HU in the central area of the affected side.

CONCLUSIONS

This study showed a decrease in bone mineralization density in the central glenoid in shoulders with rotator cuff tear. This change was observed in the case of larger cuff tears and subscapularis tendon tears. Our results help clarify the changes in stress distribution in the shoulder joint caused by symptomatic rotator cuff tears.

Crystallographic orientation of the c-axis of biological apatite as a new index of the quality of subchondral bone in knee joint osteoarthritis

The aim of the present study was to investigate the preferred orientation of biological apatite (BAp) as a new index of the quality of subchondral bone (SB) in knee joint osteoarthritis (OA). Ten OA and five normal knee joints were obtained. Thickness, quantity and bone mineral density (BMD) of SB were analyzed at the medial condyle of the femur in dry conditions by peripheral quantitative computed tomography. In addition, the preferred crystallographic orientation of the c-axis of BAp was evaluated as bone quality parameter using a microbeam X-ray diffractometer technique. BMD and thickness of SB were significantly increased in OA specimens compared to normal knee specimens (P < 0.01), and the preferred orientation of the c-axis of BAp along the normal direction of SB surface was significantly higher in OA specimens (P < 0.01), reflecting the change in stress of concentration in the pathological portion without cartilage. SB sclerosis in OA results in both proliferation of bone tissues and enhanced degree of preferential alignment of the c-axis of BAp. Our findings could have major implications for the diagnosis of clinical studies, including pathologic elucidation in OA.

The J-Shaped Bone Graft for Anatomic Glenoid Reconstruction: A 10-Year Clinical Follow-up and Computed Tomography-Osteoabsorptiometry Study

BACKGROUND

The J-shaped bone graft procedure is one of the recommended methods to reconstruct significant glenoid rim defects.

PURPOSE

To evaluate long-term (minimum 10-year) clinical outcomes and show further details of the remodeling effects on the articular cavity of the glenoid after J-shaped bone grafting.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 14 patients treated with a J-shaped bone graft procedure were observed clinically. Additionally, bilateral preoperative and postoperative follow-up computed tomography (CT) scans were used for CT-osteoabsorptiometry (OAM) to evaluate the bony remodeling processes.

RESULTS

The follow-up rate was 93% at a mean follow-up time of 10.7 years (range, 10.08-11.75 years). Patients exhibited a mean Constant score of 92.5 (range, 80-100) on the clinical evaluation. All patients had free range of motion and were pain free without any recurrence of instability. Based on CT-OAM, comparable and almost anatomically reconstructed, bilaterally equal glenoid cavities were found postoperatively. The distribution patterns of glenoid subchondral mineralization were bilaterally equal in 85.7% of the patients.

CONCLUSION

The surgical treatment of recurrent shoulder instability with a significant bony Bankart lesion using the J-shaped bone graft procedure provided excellent long-term results. This study lends evidence to support the capability of the J-shaped bone graft procedure to restore the normal glenoid shape due to physiological remodeling processes.

Elevated marrow inflammatory cells and osteoclasts in subchondral osteosclerosis in human knee osteoarthritis

Subchondral osteosclerosis, characterized by an increase of hypomineralized bone material, is a pathological hallmark of osteoarthritis. The cellular components in the subchondral marrow compartment that participate in this aberrant bone remodeling process remain to be elucidated. This study assessed the presence of marrow inflammatory cells and their relative abundance between nonsclerotic and sclerotic tissues in knee osteoarthritis. Bone samples from osteoarthritic knee tibial plateaus were stratified for histological analyses using computed tomography osteoabsorptiometry. Immunohistological analysis revealed the presence of CD20 (B-lymphocyte) and CD68 (macrophage), but not CD3 (T-lymphocyte) immunoreactive mononuclear cells in subchondral marrow tissues and their relative abundance was significantly increased in sclerotic compared with nonsclerotic bone samples. Multinucleated osteoclasts that stained positive for CD68 and tartrate-resistant acid phosphatase, predominantly associated with CD34-positive blood vessels and their abundance was strongly increased in sclerotic samples. Bone-specific alkaline phosphatase activity in outgrowth osteoblasts was induced by conditioned medium from nonsclerotic, but not sclerotic, bone pieces. These results suggest that an interaction between bone-resident cells and marrow inflammatory cells might play a role in aberrant bone remodeling leading to subchondral osteosclerosis. Elevated osteoclast activity in sclerotic bone suggests that bone formation and resorption activities are increased, yet uncoupled, in human knee osteoarthritis.

Increased Osseous (99m)Tc-DPD Uptake in End-Stage Ankle Osteoarthritis: Correlation Between SPECT-CT Imaging and Histologic Findings

BACKGROUND

We analyzed the histopathologic findings in end-stage osteoarthritic ankle joint tissue that display increased uptake of bone-seeking radiotracer in single-photon emission computed tomography-computed tomography (SPECT-CT) imaging.

METHODS

Six consecutive patients with end-stage osteoarthritis undergoing total ankle replacement received preoperative SPECT-CT imaging using (99m)Technetium dicarboxypropane diphosphonate ((99m)Tc-DPD). Using imaging data for stratification, osteochondral tissue sections were prepared from SPECT-positive (+) and -negative (-) areas of tibial and talar resection specimens. Histomorphometric analyses of osteoblast numbers, collagen deposition, and cartilage degeneration were performed on hematoxylin and eosin, van Gieson's and Safranin-O stained tissue sections. Osteoclast activity was visualized using tartrate-resistant acid phosphatase (TRAP) staining.

RESULTS

Increased (99m)Tc-DPD uptake was observed exclusively subjacent to the subchondral bone plate of tibial and talar joint compartments. SPECT(-) tissues displayed typical fatty marrow morphology containing mainly collagen-positive blood vessels and few marrow and bone-lining cells. SPECT(+) tissues were characterized by increased numbers of active bone-lining osteoblasts depositing collagen fibers. Collagen area fraction of subchondral bone marrow was significantly increased in SPECT(+) (0.52 ± 0.21) compared with SPECT(-) (0.29 ± 0.13) tissues (P = .30). Multinucleated TRAP(+) osteoclasts were absent from bone formation sites, but associated with vascular structures invading articular cartilage through the subchondral bone plate. Increased (99m)Tc-DPD uptake was specifically and strongly correlated with increased osteoblast numbers (P = .011), and with collagen area fraction (P = .030) but not with Mankin score (P = .202), or with osteoclast number (P = .576).

CONCLUSION

Subchondral bone tissues in SPECT(+) areas of end-stage ankle osteoarthritis were histologically characterized by increased osteoblast-mediated bone formation in the absence of functional osteoclasts, and increased cellularity and collagen deposition in marrow tissues.

CLINICAL SIGNIFICANCE

Our findings suggest a pathologic bone-remodeling process in end-stage ankle OA areas with increased (99m)Tc-DPD uptake.