Autologous chondrocyte implantation has long-term benefits for knee cartilage lesions

Tom Minas, MD

This excellent study by Biant, Bentley, Vijayan, Skinner and Carrington from Stanmore, United Kingdom, emphasizes the difficulty managing articular cartilage lesions on knees multiply operated upon with prior failed cartilage repair techniques (1.3 prior surgeries) — “the salvage knee.” This large series on 104 patients prospectively followed of young patients with an age of average 30 years who had large cartilage defects (5 cm2 on average) has suffered on average almost 8 years before being given an effective treatment for their painful knee. Treatment with autologous chondrocyte implantation (ACI) at 10-years minimum follow-up is still effective in 74% of patients with a 26% failure rate on average 5.7 years after treatment with ACI. In the surviving cases, 88% were good and excellent, 12% fair and poor.

Our own work mirrors almost identical outcomes. When reviewing 220 patients with prior marrow stimulation and 110 patients with no prior cartilage surgery, we found an 8% failure rate in the “virgin” knee after ACI compared with a 26% failure rate after prior marrow stimulation surgery. The concept that marrow stimulation technique as a first line treatment for all cartilage injuries “doesn’t burn any bridges” just does not hold up to the data. Our long-term results showed that those patients undergoing correction of malalignment had the best survivorship with 90% doing well at 15 years to 17 years postoperatively, and those with prior marrow stimulation procedures fared much worse at 60%. Prior work from the same department at Stanmore demonstrated in a large patient series of 827 patients for 6.2 years on average a five times increased failure rate after prior cartilage regenerative surgery.

When one considers the articular surface as an “osteochondral functional unit,” it is not too surprising that penetrating the subchondral bone to obtain marrow cells results in bone healing with thickening, intralesional osteophyte formation, subchondral cyst formation and an often a hostile environment for the possibility of restoration of a new osteochondral functional unit with ACI after a failed marrow stimulation. In this situation, ACI fails by delamination or degeneration from a stiff subchondral plate most frequently. This underscores the importance of providing the best treatment the first time with ACI, avoiding prolonged suffering and the best chance at a durable, long-term outcome for a young patient.

References:

Minas T. Am J Sports Med. 2009;doi:10.1177/0363546508330137.

Minas T. Clin Orthop Relat Res. 2013;doi:10.1007/s11999-013-3146-9.