gms | German Medical Science

Questionnaire: Reconstruction of large joint defects represents a challenge for the orthopedic surgeon. Current treatment options are limited to autograft or allograft transplantation or the implantation of a partial or total joint replacement. Our goal was to develop novel customized, cell-based osteochondral constructs to regenerate large osteochondral defects in humans.

Methods: 3-D rapid prototyping models of 5 patients with large defects of the knee joint were manufactured. The models were used to create a 3-dimensional customized bone graft from the iliac crest. These grafts were seeded with chondrospheres obtained from autologous chondrocytes amplified during a 6-8 weeks culture period. The constructs were implanted into the defects. Bone formation was assessed by plain radiographs and co-registration of a bone scintigraphy and computed tomography (SPECT). Biopsies were taken 6 months after implantation during second look arthroscopy and the KOOS and Tegner Scores are reported for these patients during a follow-up period of 2 years.

Results and conclusions: The local bone metabolic activity was increased compared with the contralateral side (Implant: 940.3±528.3, Control: 86.7±30.2, Quotient: 12.2±5.9, P<0.02).

Table 1 [Tab. 1].

Biopsies demonstrated viable subchondral bone and hyaline-like cartilage formation. Tegner scores improved from from 0.6±0.5 to 1.6±0.9, 3.4±1.8, and 3.6±1.8 (p<0.03 between pre- and 2 years post-op). The KOOS was 18.6±13.5 pre-OP, 67±8.0 (3 months), 72.7±7.0 (12 months), and 74.2±7.0 (24 months). This increase was significant between pre- and post-OP for all time intervals (p< 0.05). One case treated with reconstruction of the patella sustained a stress fracture that healed within 9 months.

Figure 1 [Fig. 1].

Interpretation: This case series demonstrates that customized autografts can be successfully seeded with autologous chondrocytes and that patients benefit from the implantation of these grafts. These complex reconstructions need individual planning and in most instances, additional surgical procedures are needed.