Results from Swedish Series

The series consisted of 153 patients who received autologous chondrocyte implantation for various defects of the knee. Patients presented with cartilage defects of the femoral condyle, patella, tibia, a combination of these, or osteochondritis dissecans, with or without comorbidity such as anterior cruciate ligament insufficiency requiring reconstruction.

Clinical Outcome - Patients with Femoral Condyle Lesions

A total of 78 of 153 patients had femoral condyle lesions with or without co-morbidity. Patients had one or more defects ranging in size from < 1-20 cm2. Of the patients with femoral condyle lesions, 40 were evaluable after at least 18 months (median = 25; range = 18 to 94 months). Clinical outcomes for the 40 patients are summarized in this table:

Defect Resumed All Activities Some Improvement No Improvement Total Patients
Femoral Condyle 7
Femoral Condyle plus other Non-Cartilage Repair 4
Total 11

Therefore, of the 40 patients evaluated after at least 18 months, 70% either resumed all activities or had some improvement.

Clinical Outcome – Patients With Osteochondritis Dissecans (OCD) Lesions

Of the 12 patients who received autologous cultured chondrocytes for treatment of an OCD lesion, 6 of the 12 had “resumed all activities,” 4 had “some improvement” and 2 had “no improvement” after the 18-month (median = 25; range = 18-94 months) follow-up period.

Therefore, of the 12 OCD patients evaluated after at least 18 months, 83% either resumed all activities or had some improvement.

Safety Outcomes

Of 153 patients treated with autologous cultured chondrocyte implantation in the Swedish Series, 22% (34/153) of patients experienced the adverse reactions presented in this table:

Initial ACI Experience Swedish Series Serious Adverse Reactions

(Occurring at a frequency of 1% or more)
Serious Adverse Reactions % of 153 Patients
Tissue hypertrophy See below
Intra-articular adhesions 8%
Superficial wound infection 3%
Hypertrophic synovitis 3%
Post-operative hematoma 2%
Adhesions of the bursa suprapatellaris 2%
Hypertrophic synovium 1%

About 1% of patients developed severe adhesions resulting in “frozen knee” and requiring lysis. Adverse reactions noted at a level of less than 1% included keloid-like scar, pannus formation, significant swelling of the joint, pain with post-operative fever, and hematoma following arthroscopy.

In this series, arthroscopy was scheduled to be undertaken at 18 months of follow up, regardless of patient symptoms.

  • Of the patients who had arthroscopy, 43% (37/86) had hypertrophic tissue.
  • Forty of the 85 patients had femoral condyle defects.
  • Of these, 25% (10/40) of patients had some hypertrophic tissue noted at follow-up arthroscopy.
  • Some patients had clinical symptoms that included painful crepitations or catching, and these symptoms generally resolved after arthroscopic resection of the hypertrophic tissue.
  • Ten percent (10%) of patients with hypertrophy required additional treatment after hypertrophic tissue recurred following initial resection.
  • Not all patients with tissue hypertrophy noted at arthroscopy were symptomatic.