Promising 9-year results seen after MACT for articular cartilage knee defects
Researchers discovered significant improvements in IKDC, Lysholm and modified Cincinnati activity scores.
NEW ORLEANS — Investigators found good long-term outcomes in patients with full thickness articular cartilage defects of the knee that underwent matrix associated chondrocyte transplantation, according to a study presented at the American Academy of Orthopedic Surgeons Annual Meeting.
“Our results showed significant and stable improvement over all times of follow-up,” presenter David Stelzeneder, MD, of the Medical University of Vienna, Austria, said.
Stelzeneder and colleagues prospectively followed 22 women and 31 men who underwent articular cartilage defect repair with the hyaluranon-based matrix-associated chondrocyte transplantation (MACT) product Hyalograft C autograft (Biotech; Rezeszow, Poland). Patients had a mean age of 32 years and were followed for an average of 9.1 years. The researchers included patients aged younger than 55 years with stable knee joints, regular knee alignment and single cartilage defects; however, they included 11 patients who did not fit this, some with early signs of osteoarthritis (OA). Overall, 27 patients had a previous surgery and 12 of these underwent prior marrow stimulation techniques such as microfracture or drilling. The mean defect size was 4.4 cm2 and most were located on the medial femoral condyle, according to Stelzeneder.
The researchers stratified patients using a classification developed by Thomas A. Minas, MD, which categorized patients into simple (23 patients), complex (22 patients) or salvage (eight patients) cases. “Salvage cases were cases with early osteoarthritis,” Stelzeneder said. “Simple cases were single defects on femoral condyles less than 4 cm2.”
The surgical technique was two-stage; first, surgeons arthroscopically harvested chondrocytes from patients and then reimplanted the cell-matrix construct 4 weeks later with mini arthrotomies or arthroscopically, Stelzeneder said. The rehabilitation protocol included full weight-bearing at 12 weeks postoperatively.
The IKDC subjective score improved significantly from 40.4 points preoperatively to 74.7 points postoperatively at 10 years, according to Stelzeneder. The Lysholm and modified Cincinnati activity scores improved significantly from preoperatively to postoperatively, but older patients had less improvement in Lysholm scores.
There were 12 graft failures that needed further surgery. The researchers noted one failure in the simple group, four in the complex group and seven in the salvage group. Only three of 42 cases with primary indications for MACT failed, which was most likely due to noncompliance or trauma. However nine of 11 patients with secondary indications failed due to progression to OA.
“We know that the classical autologous chondrocyte implantation technique shows good long-term results; however, for the matrix-associated chondrocyte transplantation technique, no long-term results have been published in the literature so far,” Stelzeneder said. “Matrix associated chondrocyte transplantation should not be applied in patients with osteoarthritis as a salvage therapy. Patients younger than the age of 40 years with single defects, stable knee joints and good compliance benefit in most cases from this therapy.” The full paper of this study was recently published by Brix and colleagues in the American Journal of Sports Medicine. – by Renee Blisard Buddle
Stelzeneder D. Paper #461. Presented at: American Academy of Orthopaedic Surgeons Annual Meeting; March 11-15, 2014; New Orleans.
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Disclosure: Stelzeneder has no relevant financial disclosures.