6 research outputs found
Autologous chondrocyte implantation of the knee using an inert collagen membrane
The hypothesis for this thesis was that using cultured autologous chondrocytes would lead to repair of full thickness defects with a hyaline type cartilage reparative tissue producing a significant improvement in pain and joint function in both the short and medium term. It was also hypothesised that the cover to contain the implanted cells is only a containment device so can be biologically inert resulting in no difference between Autologous Chondrocyte Implantation (ACI) and Matrix Assisted Chondrocyte Implantation (MACI).
For this study autologous cultured chondrocytes were re-implanted under (ACI) or within (MACI) an inert type I/III collagen membrane. Patients were clinically assessed for up to seven years by standardised objective and subjective scores, as well as undergoing a second arthroscopy at one year to assess the regenerating tissue within the defect.
All patients treated had full thickness chondral defects (1-12 cm^2).and were aged between .15-55 years age. The majority of patients had undergone at least one surgical procedure prior to referral for this technique, most commonly arthroscopy. The objective and subjective scores used showed a significant improvement post-surgery and the Short Form 36 proved to be sufficiently sensitive to demonstrate perceived health benefit from ACI at one year. ACI also resulted in an increase in post-operative score in patient previously treated with microfracture. The study showed that defect site, duration of symptoms, gender, defect size, and pre-operative score all affected the post-operative score.
Histological assessment of the repair tissue showed that the regenerate is fibrocartilaginous but continues to adapt with time post-surgery resulting in a tissue more like normal articular cartilage. However, the type of regenerate does not significantly affect the post-operative patient score. Standard histological techniques showed that the regenerate contained collagen type IIA and B, collagen X, proteoglycans and S100. The results showed that the reparative tissue is showing features of hyaline cartilage but its architectural structure is not yet formed and the on the superficial surface only fibrous tissue is found architectural structure is not yet formed and the on the superficial surface only fibrous tissue is found.
Both ACI and MACI produced significant improvements in knee function when compared to pre-operative levels (p<0.0001), with continued improvement in outcome for up to seven years, but the rate of clinical improvement in the MACI group was superior. There was, however, a greater tendency in the MACI group for fibrocartilaginous repair. This may be the reason why the MACI group had an inferior post-operative score at one year post-implantation compared to ACI group. However, by two years the MACI score surpassed the ACI group, possibly indicating a slower rate of maturation of the MACI regenerate.
In summary, ACI for the repair of full thickness defects of the knee produces a repair with a tendency to form hyaline-like articular cartilage. Subjective and objective scores demonstrate sequential improvement for up to seven years demonstrating the durability of this technique in this group of patients