No difference between serum and serum-free cultivation for ACT

All patients showed good clinical outcome scores in ICRS, Cincinnati, Lysholm and Tegner tests for each cultivation system, researchers report.

Issue: Issue 2 2006

The first prospective clinical outcome study comparing serum cell cultivation and serum-free cell cultivation in autologous chondrocyte transplantation found no significant differences in outcomes between patients treated with the two cultivation systems.

Matthias Steinwachs, MD [photo]
Matthias Steinwachs

Preoperatively and at six months and 12 months postop, clinical examinations showed that patients in the bovine serum expansion group had International Cartilage Repair Society (ICRS), Cincinnati, Lysholm and Tegner scores similar to those of the patients treated with serum-free cell expansion.

Although serum cell cultivation offers several advantages, such as high standardization of the serum components, reliable cell expansion and availability, it does present disadvantages, including animal proteins and infection risk, according to Matthias Steinwachs, MD, of the University Hospital Freiburg in Freiburg, Germany.

“We get the same results by using the serum-free condition as we do from the bovine serum-expanded cells,” Steinwachs said at the 6th Symposium of the International Cartilage Repair Society.

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At 12 months postop, researchers found no significant difference in ICRS, Cincinnati, Lysholm or Tegner outcome scores between patients treated with bovine serum and those treated with serum-free expansion.

ACT with Chondro-Gide

Between 2003 and 2004, 68 patients with symptomatic grade III and IV cartilage defects in the knee joint were treated with autologous chondrocyte transplantation combined with the Chondro-Gide (Geistlich Biomaterials) collagen membrane (ACT-C) “to protect any bleeding and to protect this culture in the biopsy,” Steinwachs said.

Researchers documented the complete results for only 56 patients (82.4%) at preop, six-month and 12-month follow-up. They split the patients into two groups, each with 28 patients, that were similar in mean age, defect size and body mass index (BMI).

Patients in Group A, treated with the bovine-serum cell cultivation, had a mean age of 34.4 ± 8.4 years, a defect size of 5.7 ± 2 cm² and a BMI of 24.1 ± 2.7. Patients in Group B, treated with serum-free cell cultivation, had a mean age of 34.9 ± 8.8 years, mean defect size of 5 ± 1.4 cm² and BMI of 24 ± 2.8.

During the autologous chondrocyte implantation procedure, surgeons performed a cartilage biopsy, mechanical and enzymatic digestion and ex vivo chondrocyte expansion. They then transplanted the cells using Chondro-Gide (Geistlich Biomaterials) collagen membrane to prevent bleeding and protect the biopsy culture, as seen here.

Courtesy of Matthias Steinwachs

Patients in Group A had defects evenly split among the medial/lateral condyle and patella/trochlea. In Group B, however, 57% of patients had defects in the patella/trochlea while 43% of patients had a defect in the medial/lateral condyle.

Steinwachs said surgeons used a standardized procedure, including cartilage biopsy, mechanical and enzymatic digestion, ex vivo chondrocyte expansion and transplantation of 10⁶ cells/cm² and Chondro-Gide collagen membrane. The standardized rehabilitation program involved crutches for six weeks and limited range of motion, depending on defect location.

No differences in outcomes

Researchers found that all 56 patients “profited significantly from the applied therapy (P<.05),” they wrote in the abstract, and they found no significant differences comparing the two groups on all four clinical scores. Serum-free expansion of autologous chondrocytes was found to trigger a standardized cell expansion, with good clinical outcome at one-year follow-up.

Also at one-year follow-up, researchers found differences comparing cultivation types according to defect location, but these differences were not significant.

“When we look at the location of the defect, we see also that the outcome is dependent on the type of cultivation by defect in the medial or lateral condyle, but [with] no significant differences,” Steinwachs said. “And we see the same in the patella/trochlea. [We find] nearly the same outcome [with] some differences, but they are not significant.”

However, researchers observed significant differences in defect location among patients in Group A. Those patients treated with bovine serum in the medial/lateral condyle had lower outcome scores for ICRS, Cincinnati and Lysholm tests and higher Tegner scores than those patients treated with bovine serum in the patella/trochlea.

For more information:
Steinwachs MR, Kreuz PC, Huber C. The first prospective clinical outcome study of ACT by use of serum-free medium for cell cultivation. #10c-3. Presented at the 6th Symposium of the International Cartilage Repair Society. Jan. 8-11, 2006. San Diego.