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Because various biomechanical studies and clinical results have shown the effectiveness of an anatomical approach for anterior cruciate ligament (ACL) reconstruction, this approach has become gradually commonplace to improve postoperative performance. Standard tunnel positioning methods with accuracy, reproducibility, and adaptability to varied concepts are essential for the success of anatomical ACL reconstruction. However, there were no standard tibial tunnel positioning methods to satisfy these conditions. This technical note reports our tibial tunnel positioning technique using bony and/or anatomical landmarks for anatomical ACL reconstruction.

Purpose To assess (1) if 6 anatomic landmarks (ALs) could be arthroscopically confirmed with remnant preservation and (2) if creating tibial tunnels using these landmarks reduces individual variation and improves reproducibility in double-bundle anterior cruciate ligament (ACL) reconstruction. Methods We retrospectively reviewed data of patients who chronologically underwent double-bundle ACL reconstruction by either referencing the footprint after remnant dissection (non-AL group) or subsequently with the ALs (AL group). Using operative videos, 3 independent observers judged whether they could confirm 6 ALs (medial intercondylar ridge, medial and lateral intercondylar tubercles, anterior horn of lateral meniscus, Parsons' knob, and L-shaped ridge) in 20 patients randomly selected from the AL group. We then compared tunnel positions between the 2 groups, measured from the anterior and medial borders of the proximal tibia and expressed as percentage of the total depth and width of the proximal tibia using 3-dimensional computed tomography. Results One hundred four patients (non-AL group, n = 54; AL group, n = 50) were included. All 6 ALs were arthroscopically confirmed in most cases (89.7% to 100%). The mean percentages of the anteroposterior (AP) depth for anteromedial (AM) tunnel, mediolateral (ML) width for AM tunnel, AP depth for posterolateral (PL) tunnel, and ML width for PL tunnel, respectively, were 27.8% ± 6.6%, 46.7% ± 2.8%, 41.4% ± 7.3%, and 46.1% ± 2.6% for the non-AL group and 30.7% ± 4.5%, 45.7% ± 2.2%, 45.2% ± 4.5%, and 46.9% ± 2.1% for the AL group, revealing significantly less variation in the AL group compared with the non-AL group, excluding the ML width of the PL tunnel ( P = .007, .046, .002, .209, respectively). Conclusions Six landmarks could be reliably confirmed in cases with remnant preservation, and creating tibial tunnels using these landmarks were reproducible and resulted in less individual variation. Level of Evidence Level III, retrospective comparative study.

The linear penetration rates for ceramic femoral heads on conventional and highly cross-linked polyethylene were measured and compared with radiographs taken in the standing and supine position taken three weeks postoperatively and at final follow-up. Seventy-five patients (83 hips) with conventional polyethylene (group-1) and two hundred and seventy five patients (300 hips) with highly cross-linked polyethylene (group-2) were studied. Follow-up periods were 14.5years in group-1 and 8.6years in group-2. The average penetration rates in group-1 were 0.17mm/year in supine position and 0.18mm/year in standing position (P

Fourteen hips in 14 patients (all female; average age, 64 years) with severe bone defects due to developmental dysplasia of the hip or migration of the socket were treated with hydroxyapatite block with impacted morselized bone graft in conjunction with a cemented socket. All patients were followed clinically in a prospective fashion, and radiographs were analyzed retrospectively. One initial patient had 17-year follow-up, whereas the remaining 13 patients had follow-up between 4 and 6.5 years. No acetabular components were revised, including the socket of a 17-year postoperative case that remains rigidly fixed and supported by the graft and hydroxyapatite block with only mild polyethylene wear and minor osteolysis. Osteointegration and good clinical outcome were achieved in all cases by reconstruction with this technique in total hip arthroplasty.

To examine how fibroblast growth factor-2 (FGF-2) affects the BMP signaling pathway during bone morphogenetic protein-2 (BMP-2)-induced ectopic bone formation, we implanted type I collagen disks containing constant amounts of BMP-2 (5 micrograms) and varying amounts of FGF-2 onto the back muscles of adult male mice. We then performed histological analyses and histomorphometry, and measured bone mineral density and radiopaque area on the discs 1, 2, and 3 weeks after implantation. We also determined the expression profiles of several genes involved in bone formation and the BMP signaling pathway in the muscle that had been adjacent to the implanted disc and in muscle-derived primary culture cells that had similarly been treated with a constant concentration of BMP-2 and a varying concentration of FGF-2. In the presence of a constant amount of BMP-2, we confirmed that low doses of FGF-2 increased ectopic bone formation in vivo and high doses inhibited bone formation. Northern and/or Western blots of recovered muscle from the in vivo experiment and treated muscle-derived primary culture cells from the in vitro experiment revealed that low doses of FGF-2, but not high doses, increased the expression BMP receptor (BMPR)-1B, phosphorylated Smad1, Noggin, and Osteocalcin. Our results indicate that low-dose FGF-2 may facilitate BMP-2-induced ectopic bone formation by altering the expression of BMPRs on the surface of bone forming progenitor cells. They also indicate that the inhibitory effect of high-dose FGF-2 is not mediated via increased expression of the BMP inhibitor Noggin.