The Mini-Pig as an Animal Model for Focal Cartilage Treatment of the Knee—A Comparison to the Domestic Pig

Aim: This study aims to assess the suitability of the Göttingen Mini-pig (G-MP) as a large animal model for preclinical research on articular cartilage treatment procedures. Additionally, this study compares the G-MP to the domestic pig (DP) regarding surgical anatomy, postoperative care, and the challenges associated with the follow-up period. Materials and methods: Six G-MPs and four DPs underwent a two-stage surgical procedure: first, cartilage was harvested using a superolateral approach, followed by cartilage implantation via a medial parapatellar tendon approach. Results: The superolateral approach exposed 11% (SD ± 5) of the trochlea in G-MPs and 20% in DPs. The medial parapatellar tendon approach exposed 63% (SD ± 4) of the trochlear surface and 34% (SD ± 13) of the medial femoral condyle in G-MPs, allowing for the creation of four 6 mm trochlear lesions and one medial condyle lesion in four out of six G-MPs and all DPs. Cartilage thickness was less than 1 mm in G-MPs, compared to over 2 mm in DPs. Weight gain was +4 kg/week in DPs and +0.2 kg/week in G-MPs. Conclusion: Overall, the G-MP proves to be a viable model for cartilage research, offering sufficient joint access via the dual approach, which allows for 4–5 lesions of 6 mm each. However, the thinner cartilage in G-MPs should be taken into account.