Crushed bone grafts and a collagen membrane are not suitable for enhancing cartilage quality in the regeneration of osteochondral defects—An in vivo study in sheep

Treatment of osteochondral defects: chondrointegration of metal implants improves after hydroxyapatite coating

PURPOSE

The treatment of osteochondral defects in joint cartilage remains challenging due to its limited repair capacity. This study presents a metallic osteochondral plug with hydroxyapatite (HA)-coated cap edges for improved implant-tissue contact. The hypothesis was that improved attachment prevents from synovial fluid-influx and thereby avoids osteolysis and resulting implant instability.

METHODS

In total, 24 female, adult sheep were randomized into three groups. All animals received an Episealer^®-implant in the medial condyle of the right knee. The implants were coated with two different HA versions or uncoated (control group). After 12 weeks, the implant-tissue connections were analysed radiologically and histologically.

RESULTS

In general, the groups with the coated cap edges showed a better quality of tissue connection to the implant. The occurrence of gaps between tissue and implant was more seldom, the binding of calcified and hyaline cartilage to the cap was significantly better than in the uncoated group. A histomorphometrically measured lower amount of void space in these groups compared to the group with the uncoated edges confirmed that.

CONCLUSIONS

The hypothesis of a tighter cartilage bone contact was confirmed. The HA coating of the implant's cap edges resulted in better adherence of cartilage to the implant, which was not previously reported. In conclusion, this led to a better contact between implant and cartilage as well as neighbouring bone. In clinical routine, joint fluid is aggressive, penetrates through cartilage rifts, and promotes osteolysis and loosening of implants. The observed sealing effect will act to prevent joint fluid to get access to the implant-tissue interfaces. Joint fluid is aggressive, can cause osteolysis, and can, clinically cause pain. These effects are liable to decrease with these findings and will further the longevity of these osteochondral implants.

HISTOLOGICAL MARKERS OF DEGENERATION AND REGENERATION OF THE HUMAN INTERVERTEBRAL DISK

ABSTRACT Objective: To define histological scores for intervertebral disc degeneration that would enable the definition of morphological characteristics of disease, besides improving knowledge of the lumbar degenerative disc disease by means of immunohistochemical markers. Methods: Hematoxylin and Eosin, Alcian/PAS, Masson Trichrome and Safranin O/FCF staining was used on the intervertebral disc degeneration sections of patients with lumbar degenerative disc disease. The protein markers defined in immunohistochemistry were cell proliferation (Ki-67) and apoptosis (p53). Results: The study data enabled the determination of Safranin O/FCF stain as the most effective one for evaluating parameters such as area, diameter, and number of chondrocyte clusters. The importance of using stains in association, such as Safranin O/FCF, Masson Trichrome, Alcian/PAS and Hematoxylin and Eosin, was also determined, as they are complementary for the histopathological verification of intervertebral disc degeneration. By expressing proteins using the immunohistochemistry technique, it was possible to consider two stages of disc degeneration: cell proliferation with chondrocyte cluster formation, and induction of apoptosis. Conclusion: This study enabled the histological and immunohistochemical characterization to be determined for lumbar degenerative disc disease, and its degrees of evolution, by determining new disc degeneration scores.