This study demonstrates a rapid, safe, and effective treatment for cartilage defects. For the patient population investigated, the clinical outcomes of the PJAC technique showed a significant improvement over baseline, with histologically favorable repair tissue 2 years postoperatively.

Studies show that human amniotic cells' pluripotentency can be influenced to produce chondrocytes and osteocytes through adding demineralized bone (DMB). Objective: This study evaluates the human amniotic membrane (HAM) mixed with DMB to fill defects in sheep models. We hypothesized this membrane would fill these defects with hyaline-like cartilage with chondrocytes populating the matrix. Design: Six adult sheep were used in this study. One hindquarter knee of each sheep was utilized to make two cartilage defects: one on the femoral condyle and one in the trochlear grove. Three control sheep had unfilled defects. Three sheep received HAM/DMB from a placenta to fill the defects. The membrane was folded so the cellular layer faced the defect and the joint while demineralized bone was placed between the layers. The membranes were fixed to the femur and to the trochlear grove. At six months, the sheep were sacrificed for evaluation. Results: Of the controls, defects did not fill with hyaline or fibrocartilage. In HAM/DMB sheep, 50% of the defects retained the membrane, consistent with other animal models. Membrane defects were examined histologically by a validated scoring system. A strong correlation of little statistical difference between the test and the normal cartilages was observed. The defects that retained membranes had evidence of diffuse chondrocyte-like cell proliferation of stromal matrix similar to hyaline cartilage. Conclusions: HAM/DMB is a potential source of pluripotent cells that can influence chondrogenesis in defects in sheep models. The implications for application in a human model are promising and warrant further study.

Objective: To evaluate the use of hypothermically stored human amniotic membrane for cartilage repair in adult sheep. Studies show that human amniotic membrane contains pluripotent mesenchymal stem cells that can be influenced to produce chondrocytes. It is unknown if human amniotic cells can produce hyaline-like cartilage. This study evaluates the use of hypothermically stored amniotic membrane (HSAM) to fill chondral defects in a sheep model. We hypothesized HSAM would fill defects with hyaline-like cartilage with chondrocytes populating the matrix. One sheep was used as a control, and four sheep received amniotic membrane. Two of these sheep were used as a normal control comparison. A 1 cm 2 defect was created on the trochlear grove in all specimens. Each membrane was sized and laid over with the stromal layer facing the subchondral bone and covered with Fibrin sealant. The knees were harvested at five months and underwent morphological, histological, and immunohistological evaluation based on the original validated scoring system by O'Driscoll. The control defect didn't fill in with hyaline cartilage or fibrocartilage. The defects that successfully retained the graft had evidence of diffuse chondrocyte cell proliferation and showed a stromal matrix similar to hyaline cartilage. The graft samples showed a near 100% morphological fill in the HSAM defect contrasting to <10% fill in the control defect. The retained HSAM grafts scored 2.5 on a 0 -3 cartilage appearance scale compared with 0.5 for the control defects. HSAM is a potential source of pluripotent cells that can influence chondrogenesis in a sheep model. The implications for application in a human model are promising and warrant further study.

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Objective The purpose of this study was to determine the safety and efficacy of hypothermically stored amniotic membrane (HSAM) for the treatment of cartilage lesions of the knee using imaging, patient-reported outcomes (PROs), second-look arthroscopy, and histology. Patients were treated with HSAM and followed for 2 years. Design Subjects with focal chondral lesions of the femur (International Cartilage Repair Society grade 3-4) were enrolled in this single-arm prospective study. Standard of care imaging was completed. PROs, including the Knee Injury and Osteoarthritis Outcome Score (KOOS), Marx Activity Scale, and Visual Analog Scale (VAS), were collected at baseline and at 3, 6, 12, 18, and 24 months. Three subjects underwent an optional arthroscopy and biopsy of the repair at 24 months. Results Ten subjects were enrolled and completed the study. At 24 months, KOOS Sports & Recreation improved 173.3% and Quality of Life improved 195.3% from baseline. Marx Activity Scale increased 266.8% from 12 to 24 months. VAS scores improved 84.8% and 81.0% from baseline to 24 months for average and maximum pain. Modified Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring showed that 7 of 10 subjects had complete defect repair and filling by 24 months. Biopsy staining for collagen II revealed integration and remodeling of HSAM into a mix of hyaline-like cartilage and fibrocartilage matrix. Conclusion This study provides evidence supporting the safety and efficacy of HSAM for treating symptomatic cartilage lesions. Subjects showed a high degree of defect fill and integration with the native cartilage and reported improvements in pain and function post-treatment. Results provide important original data for future clinical trials.