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ACI likely to produce hyaline-like repair in treatment of articular cartilage defects
Despite high price tag, need for multiple repairs, ACI offers long-term durability, biologic repair.
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Autologous chondrocyte implantation often requires multiple or staged procedures, but surgeons find it beneficial because it offers a greater chance of developing hyaline-like repair tissue and reproducible results, according to Scott D. Gillogly, MD.
In Gillogly’s 11-year experience, many patients have required multiple procedures for articular cartilage lesions. Among 377 defects in 303 patients, Gillogly has performed 224 concomitant procedures such as osteotomy, tibial tubercle elevation, ACL reconstruction and meniscal transplantation as well as 34 additional staged procedures.
“More complicated lesions require a staged procedure, oftentimes with an initial osteotomy,” Gillogly said. “Certainly, whatever is necessary to optimize the intra-articular environment needs to be done to give the articular cartilage a chance to heal with this technique.”
Gillogly discussed his experience with the autologous chondrocyte implantation (ACI) technique at the American Orthopaedic Society for Sports Medicine Specialty Day meeting.
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Images: Gillogly SD |
Why ACI?
The ACI technique offers several advantages over other repair techniques, Gillogly explained.
Studies have demonstrated the long-term durability of a successful ACI repair, he said, noting an investigation by Lars Peterson, MD, in which 97% of patients with good and excellent results at 2 years continued to do well at 8 years and 12 years follow-up.
And, because ACI is an autologous cell-based treatment, “Precursor chondrocytes really can develop into hyaline-like repair tissue, providing that nothing else interferes with that development,” Gillogly said.
Other ACI advantages include:
- the ability to recreate complex contours for difficult lesions in the knee;
- the ability to treat uncontained lesions, simple lesions and complex lesions in the entire weight-bearing compartment surface;
- the biologic nature of the repair; and
- the absence of any allograft issues, avoiding any risk of contamination, Gillogly said.
However, there are disadvantages to ACI. “It’s a two-stage procedure; it requires a biopsy to grow the cells; [and] it certainly has a cost associated with it, as all more complex cartilage treatments will have both now and in the future,” Gillogly said.
In fact, the average price of an ACI procedure, including cells, hospital and surgery is $28,000, Gillogly told Orthopedics Today.
Co-existing pathologies
Before performing ACI, Gillogly stressed the importance of assessing all potential knee co-pathologies including size of the defect, biomechanical alignment, meniscal status, bone status, ligament exam and patellofemoral tracking.
“We certainly assess these patients from a very thorough standpoint: trying to check the whole knee and not just the cartilage defect,” Gillogly said.
Articular cartilage lesions are not always isolated and vary in size, characteristics and number of lesions.
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Staged grafting
For defects with bone loss greater than 8 mm in depth, Gillogly suggested staged arthroscopic bone grafting, sealing the lesion with fibrin glue and then about 6 months later, placing autologous chondrocytes on top with a periosteal graft.
Sometimes a sandwich technique is needed, where bone grafting is done concomitantly with the ACI procedure. The graft is isolated from the cells with a layer of periosteum and another layer of periosteum is sewn on the surface, essentially sandwiching the cells, Gillogly said.
Alignment is essential for a successful cartilage repair, and osteotomy can be helpful in cases of malalignment.
“We either correct or overcorrect the mechanical axis, depending on the problem. And for any significant articular cartilage problem we want to have at least a neutral axis,” Gillogly said. “We also want to make sure that we do not inadvertently adjust the sagittal slope inappropriately.”
In cases of patellar instability and malalignment, Gillogly said to realign and unload the patellofemoral joint with anteromedialization of the tibial tubercle (Fulkerson Procedure), concomitant with ACI. Meniscal transplantation can also be performed in cases of meniscal deficiency.
The future of ACI
The next generation of ACI will include some combinations of growth factors, cell lines and biomaterials designed to enhance the maturation of the chondrocytes to more closely mimic normal hyaline cartilage, he said.
“Certainly the matrix or scaffold ACI where the chondrocytes are suspended in an absorbable biomedium and periosteal substitutes are here already – more prevalent in Europe and Asia, but signals the next generation for autologous chondrocyte implantation,” he said. “Hopefully the future generations of ACI will not only simplify cell delivery, but also improve clinical results.”
For more information:
- Scott D. Gillogly, MD, can be reached at Atlanta Sports Medicine & Orthopaedic Center, 3200 Downwood Circle, Suite 500, Atlanta, GA 30327; 404-352-4500; e-mail: sdg14@mindspring.com. He indicated that he is a consultant to Genzyme Biosurgery.
Reference:
- Gillogly SD. Symposium: Articular cartilage restoration – Use of autologous chondrocyte implantation for articular cartilage defects. Presented at the American Orthopaedic Society for Sports Medicine Specialty Day Meeting. Feb. 17, 2007. San Diego.