Effects of holmium:YAG laser on equine articular cartilage and subchondral bone adjacent to traumatic lesions: a histopathological assessment.

This research was conducted to explore the impact of holmium:yttrium-aluminum-garnet (Ho:YAG) laser on articular cartilage and subchondral bone in horses after traumatic injury. The study identified that laser treatment improved cartilage response, but also noted cellularity loss and necrosis at higher energies.

Research Methodology and Approach

• The study was conducted on four adult horses where bilateral arthroscopy was performed on normal antebrachiocarpal and intercarpal joints.
• Three types of cartilage injuries (lacerations, scrapes, and craters) of varied depth (partial and full thickness) were created artificially on their weight-bearing articular surfaces, totaling to 120 traumatic lesions.
• The left limbs of the horses served as controls while the right limb lesions were exposed to different intensities of Ho:YAG laser energy: 0.1, 0.16, and 0.2 Joules.
• Assessment was undertaken at intervals of 1, 3, and 8 weeks, during which histological changes were observed, tissues were analyzed, and the states of cartilage cellularity and proteoglycan content were evaluated using the Mankin grading system.

Research Findings

• The study found that laser energy improved the cellularity as well as the proteoglycan content of cartilage lesions when compared to the corresponding untreated controls, indicating a better healing response.
• However, higher intensities of laser treatment (0.16 and 0.2 Joules) exhibited a loss in cellularity and necrosis (cell death) in the subchondral bone underneath the cartilage.
• The Mankin grades for the 0.16 and 0.2 Joule laser treatments were also lower compared to controls or lesions treated with 0.1 Joules, indicating that balance in intensity is vital to avoid negative effects.

Conclusions and Recommendations

• The research concluded that the Ho:YAG laser has a noticeable effect on the healing of articular cartilage and subchondral bone after traumatic injury in a weight-bearing model. The laser energy improves cartilage healing but can cause potential damage to the subchondral bone at higher energy levels.
• Further research is recommended to establish dose-response curves for Ho:YAG laser treatment of cartilage and subchondral bone, which can aid in adjusting the laser intensity levels to optimize the healing effects and minimize the damage.