Changes in articular cartilage after meniscectomy and meniscus replacement using a biodegradable porous polymer implant

Purpose: To evaluate the long-term effects of implantation of a biodegradable polymer meniscus implant on articular cartilage degeneration and compare this to articular cartilage degeneration after meniscectomy. Methods: Porous polymer polycaprolacton-based polyurethane meniscus implants were implanted for 6 or 24 months in the lateral compartment of Beagle dog knees. Contralateral knees were meniscectomized, or left intact and served as controls. Articular cartilage degeneration was evaluated in detail using India ink staining, routine histology, immunochemistry for denatured (Col2-¾M) and cleaved (Col2-¾Cshort) type II collagen, Mankin’s grading system, and cartilage thickness measurements. Results: Histologically, fibrillation and substantial immunohistochemical staining for both denatured and cleaved type II collagen were found in all three treatment groups. The cartilage of the three groups showed identical degradation patterns. In the 24 months implant group, degradation appeared to be more severe when compared to the 6 months implant group and meniscectomy group. Significantly more cartilage damage (India ink staining, Mankin’s grading system, and cartilage thickness measurements) was found in the 24 months implant group compared to the 6 months implant group and meniscectomy group. Conclusion: Degradation of the cartilage matrix was the result of both mechanical overloading as well as localized cell-mediated degradation. The degeneration patterns were highly variable between animals. Clinical application of a porous polymer implant for total meniscus replacement is not supported by this study.

The long-term results of meniscus transplantation for articular cartilage defects in the knee joint

Purpose: The purpose of this study was to examine the long-term clinical results of meniscus transplantation for articular cartilage defects in the knee joint. Type of study: Case series. Method: From October 1990 to June 1995, 8 cases underwent allogenic or autogenic meniscus transplantations for articular cartilage defects, and 7 cases were available for follow-up evaluations. The age at surgery ranged from 14 to 42 years old (average 22.5). In one case, a transplantation of tissue-engineered cartilage was performed due to pain 5 years after surgery. The other 6 cases were followed up for 8 to 13 years (average 10.1). The size of the cartilage defect ranged from 1.0 cm2 to 6.3 cm2 (average 2.8cm2). Patients were evaluated with the Lysholm score and MR images. We also performed arthroscopic examinations in 3 cases at the final evaluation. Results: The Lysholm scores ranged from 76 points to 100 points. In MR images, the congruities between the grafted lesions and normal cartilage were evaluated as smooth surfaces in 4, slightly irregular surface in 1, irregular surface in 1, and one had disappeared. In arthroscopic findings at 11 years after surgery, the grafted meniscus could not be found in one knee that had severe osteoarthritis changes, and in the other knee the lesion of the transplanted meniscus resembled a flap tear. In another case, the grafted meniscus and the surrounding cartilage displayed irregular surfaces during transplantation of tissue-engineered cartilage. In histological findings, at 11 years after surgery a small lesion in the grafted area was not hyaline cartilage but fibrocartilage. Conclusions: This study leads us to the conclusion that meniscus transplantation for articular cartilage damage is not compared to ACI although two cases showed good clinical results for a short term but the tissue was remained fibrocartilage tissues for long term.. Level of Evidence: Level 4, case series

The effects of lateral meniscal allograft transplantation techniques on tibio-femoral contact pressures.

Accepted versio