One-Sixth of Knee Cartilage Treatments Need Redoing

To examine the extent, type and treatment of complications that arise from the surgery, an area that had not been investigated before, Dr. Philipp Niemeyer of Freiburg University Hospital in Freiburg im Breisgau, Germany, and his associates looked at 309 patients who had received ACI surgeries in the period 2001-06. The researchers followed the patients for an average of 4.5 years, and found that 16.8 percent of them needed to have their procedure redone due to pain or incapacitation of the knee.

There were four main types of complications: overgrowth, or hypertrophy, of the cartilage implant, which occurred in 30.8 percent of cases; unsatisfactory fusion of the graft with the healthy cartilage, a situation in 23.1 percent of patients; non-regeneration of the cartilage, in 17.3 percent of cases; and a ripping of the old cartilage near the repair, which also occurred in 17.3 percent of patients.

Surgeons used three different techniques to perform the ACI procedures. But the study revealed nothing useful that could help orthopedists craft an overall strategy to deal with ACI complications, which, the researchers say, are extremely difficult to diagnose with MRI scans, their standard diagnostic tool.

"No consistent concept can be found concerning the performed therapies for the detected complications," Niemeyer says. "Further studies need to be conducted to establish concepts and therapeutic strategies to address these complications."