Nondestructive Assessment of Articular Cartilage Electromechanical Properties after Osteochondral Autologous and Allogeneic Transplantation in a Goat Model

A New Method for Creating Impact-Induced Intra-Articular Fractures in a Rabbit Model Induces Severe Post-Traumatic Osteoarthritis

OBJECTIVES

The objective of this work was to develop a model of intra-articular fracture (IAF) in a rabbit and document the speed and severity of degenerative joint changes after fracture fixation.

METHODS

With Institutional Animal Care & Use Committee approval, impact-induced IAFs were created in the distal tibia of 16 New Zealand White rabbits. Fractures were fixed with a plate and screws. Pain and function were monitored at regular postoperative intervals with limb loading analysis. Twelve or 26 weeks after fracture, animals were euthanized for histological assessment of cartilage degeneration and micro-computed tomography analysis of bone histomorphometry.

RESULTS

Eleven animals successfully completed the study. Maximum foot force in the fractured limb was 41% ± 21% lower than preoperative values ( P = 0.006) 12 weeks after fracture and remained 25% ± 13% lower ( P = 0.081) after 26 weeks. Cortical bone mineral density in micro-computed tomography images was 34% ± 13% lower 12 weeks after fracture ( P < 0.001) and remained (42% ± 8%) lower 26 weeks after fracture ( P < 0.001). Twelve weeks after fracture, Mankin scores of cartilage degeneration were significantly higher in the medial talus ( P = 0.007), lateral talus ( P < 0.001), medial tibia ( P = 0.017), and lateral tibia ( P = 0.002) of the fractured limb compared with the uninjured contralateral limb. Average Mankin scores in the talus increased from 12 to 26 weeks (5.9 ± 0.9 to 9.4 ± 0.4; P < 0.001 lateral; 5.4 ± 1.8 to 7.8 ± 2.0; P = 0.043 medial), indicating substantial and progressive joint degeneration.

CONCLUSIONS

The ankle joint of the New Zealand White rabbit provides the smallest available model of impact-induced IAF that can be treated with clinically relevant techniques and replicates key features of healing and degeneration found in human patients.

Arthroscopic Electromechanical Assessment of Human Articular Cartilage Injury Correlates with ICRS Scores

PURPOSE

This study aimed to conduct arthroscopic evaluation of cartilage electromechanical properties and establish their correlation with International Cartilage Repair Society (ICRS) grading scores.

METHODS

In 18 patients, quantitative parameter (QP) measurements were taken on the weight-bearing surface of the medial femoral condyle. Adjacently, the same site was graded using ICRS scores (0-4). Electromechanical QPs for ICRS grades 0 to 3 were obtained during arthroscopy, while complete grade 4 injuries were assessed using femur cartilage-bone blocks from knee arthroplasty. The QP values for ICRS grades 0 to 2 were compared with grades 3 and 4 using Welch t test. The corresponding QP values were assigned to ICRS grades 0 to 4 and compared using Welch ANOVA (analysis of variance). Pearson's coefficient evaluated QP-ICRS grade relationship.

RESULTS

Healthy grade 0 cartilage displayed a mean QP value of 10.5 (±2.8 SD, n = 4). The ICRS grade 1 and grade 2 injuries were associated with QP values of 12 (±0.7, n = 2) and 13.25 (±1.77, n = 2), respectively. The grade 3 defects had QP values of 20.43 (±4.84, n = 4), whereas complete grade 4 defects showed electromechanical values of 30.17 (±2.19, n = 6). Significant differences in QP values were observed between ICRS grades 0 to 2 (mean QP 11.56 ± 2.3, n = 8) and grades 3 and 4 (26.27 ± 6, n = 10; P < 0.0001). Pearson's correlation coefficient of 0.9 indicated a strong association between higher ICRS cartilage injury grades and elevated QP values (P < 0.0001).

CONCLUSION

Arthroscopic electromechanical QP assessment robustly correlates with ICRS scores. The QP values for ICRS grades 0 to 2 are significantly lower, compared with grades 3 and 4.

Biological Changes of Autologous Auricular Cartilage in Rhinoplasty

Autologous auricular cartilage is used extensively as a good graft material in rhinoplasty. In this study, clinical specimens from patients who underwent revision rhinoplasty with auricular cartilage grafts were collected to compare the changes before and after auricular cartilage transplantation with the use of histologic, immunohistochemical, and quantitative assays. Patients who underwent revision rhinoplasty from 2018 to 2022 were analyzed. Fresh auricular cartilage left after surgery and auricular cartilage graft tissue were examined and compared. Compared with fresh auricular cartilage, local fibrosis was seen in the transplanted auricular cartilage with a slight decrease in elastic fibers, type II collagen, and extracellular matrix secretion. Quantitative assays showed a decrease in glycosaminoglycan, DNA, and total collagen content in the transplanted auricular cartilage tissue. The results of the study suggest that the histologic characteristics, cell functionality, and biochemical composition of the grafted cartilage changed to a certain extent after autologous auricular cartilage graft rhinoplasty. These results provide insights into the selection of graft/filler materials for rhinoplasty and what changes to expect.