Summary

This pilot study suggests that fresh hypothermically stored amniotic membrane may be a potential treatment option for chondral defects.

Abstract

Purpose

The limited healing potential of cartilage is due to its lack of vascularization and the innate nature of adult chondrocytes, which have little migration and replication potential in vivo. Treatment options including MACI and ACI involve the ex-vivo expansion of autologous articular chondrocytes, which is known to be costly and requires multiple surgical procedures. Human amniotic membrane (HAM) has been studied for its potential role as a substrate for the promotion of chondral regeneration and is currently used in a variety of clinical applications1. HAM is known to contain proteoglycans, growth factors, and progenitor cell populations that may be conducive to chondral repair and regeneration. Previous ovine studies demonstrated promising results using HAM for articular cartilage repair2, 3. In the current study, we have evaluated the effectiveness of a fresh hypothermically stored amniotic membrane (HSAM) for articular cartilage repair in a prospective 10 patient study.

Materials And Methods

In patients presenting with at least ICRS grade III lesions, a median parapatellar incision was made to expose the affected area on the condyle or trochlea. A sharp dissection of the defect on the normal healthy cartilage using a knife and/or ring curette was then performed. HSAM was laid stromal side down in the defect bed and secured with fibrin glue. Treatment effectiveness was evaluated via MRI, VAS, and KOOS measurements at 3, 6, 12, 18, and 24 months; however, as of abstract submission, interim results are available for MRI and VAS at the 6 and 12-month time points. At the time of presentation, some 18 and 24-month follow-up data will be available.

Results

Currently, 8 subjects have reached the 6 month follow-up time point, 7 patients have reached 12 months, 2 patients have reached 18 month follow-up and 1 patient has completed the study at 24 months. MRI scans demonstrated apparent defect fill (Figure 1), indicating increased proteoglycan content. MRI Mocart scoring demonstrated at least some degree of defect fill in 100% of the patients. All defects had integration with adjacent cartilage and bone marrow edema improved in a large percentage of the patients. VAS joint average pain scores decreased from baseline by 16.38 ± 30.99 at 3 months, 27.50 ± 26.52 at 6 months, and 28.57 ± 26.22 at 12 months. VAS maximum pain scores decreased by 28.00 ± 29.27 at 3 months, 33.63 ± 28.05 at 6 months, and 41.14 ± 32.95 at 12 months. Patients’ study expectation scores were 87 ± 11.11 at 12 months, with a score of 100 being the maximum score for satisfaction. Overall all KOOS scales improved at 6 and 12 months compared to baseline. At 12 months follow-up, KOOS pain, symptoms and quality of life scores improved from baseline 22.67, 10.78, and 35.94 points, respectively.

Conclusions

In this 10-patient pilot study, HSAM-treated patients show decreases in pain scores, along with increases in overall knee assessment scores up to 12 months post-surgery. This evidence suggests that HSAM may be a potential therapy for the treatment of cartilage defects.

References:
1. Mamede A, Carvalho M, Abrantes A, Laranjo M, Maia C and Botelho M. Amniotic membrane: from structure and functions to clinical applications. Cell and tissue research. 2012;349:447-458.
2. Tabet SK, Conner DM and Guebert DA. The Use of Human Amniotic Membrane for Cartilage Repair: A Sheep Study. Stem Cell Discovery. 2015;5:40.
3. Tabet SK, Clark AL, Chapman EB and Thal D. The Use of Hypothermically Stored Amniotic Membrane for Cartilage Repair: A Sheep Study. Stem Cell Discovery. 2015;5:62.