Validation of Indian hedgehog deletion and partial medial meniscectomy. (A) Radiographs using soft-tissue settings show medial meniscus of the left knee joint without partial medial meniscectomy (PMM) surgery (indicated by arrowhead in left panel) and absence of medial meniscus of the right knee joint (indicated by arrow in right panel). (B) Results of real-time PCR are shown. Relative fold expression of Indian hedgehog (Ihh) is decreased by 46.5% in tamoxifen (TM)-injected mice. Data are means ± SD. TM, n = 6. no TM, n = 8. *P < 0.005.