Characterization of bone remodeling of two different porous types of β-tricalcium phosphates: a quantitative site-by-site analysis using computed tomography

Use of Unidirectional Porous β-Tricalcium Phosphate in the Tibial Tunnel for Anterior Cruciate Ligament Reconstruction: A Case Series

Bone defects in the tibial tunnel for anterior cruciate ligament (ACL) reconstruction can cause adverse events. The unidirectional porous tricalcium β-phosphate (UDPTCP) has the potential to be used as a filling substitute for bone defects. In this case series, we present the first nine cases in which UDPTCP was used as a bone substitute in the tibial tunnel during ACL reconstruction. The patients comprised six males and three females, with an average age of 32 years (range: 16-50 years). A cylindrical UDPTCP measuring 10 x 20 mm was molded to fit the tibial tunnel and then implanted. At the one-year postoperative follow-up, none of the patients demonstrated any complications, and bone remodeling was observed on radiographs. Therefore, UDPTCP may provide a safe and reliable filling substitute for the tibial tunnel in ACL reconstruction.

Effect of platelet-rich plasma on the acceleration of graft bone catabolism in lateral lumbar interbody fusion in a short-term assessment

This study aimed to demonstrate whether impregnating the graft bone with platelet-rich plasma (PRP) accelerates graft bone catabolism in lateral lumbar interbody fusion (LLIF). Consecutive patients who underwent LLIF were assessed. Of the two spaces for bone grafts in the intervertebral cage, one space was filled with graft bone impregnated with PRP, and the other was filled with graft bone without PRP, which divided the graft bones into PRP and non-PRP groups. The mean Hounsfield units (HU) of the graft bone at the center of the cage space in the coronal and axial slices were measured using computed tomography (CT) images 1 week and 6 months after surgery. The delta value of HU from 1 week to 6 months after surgery was calculated for the PRP and non-PRP groups. We compared the delta values of the HU between the two groups. The PRP and non-PRP groups comprised 16 bone grafts. In the coronal slices, the HU value in the PRP group (delta value: 526.1 ± 352.2) tended to have a greater decrease at 6 months after surgery compared with that in the non-PRP group (delta value: 217.6 ± 240.4) (p = 0.065). In the axial slices, the HU value in the PRP group (delta value: 501.3 ± 319.6) was significantly decreased at 6 months after surgery compared with that in the non-PRP group (delta value: 159.2 ± 215.3) (p = 0.028). Impregnating the graft-bone with PRP accelerated graft bone catabolism in LLIF within 6 months after surgery.

Bilateral Knee Osteoarthritis Treated With Medial Open-Wedge High Tibial Osteotomy Using Two Types of β-Tricalcium Phosphate With Differing Placements in Each Knee: A Report of Two Cases

In medial open-wedge high tibial osteotomy (MOWHTO) for knee osteoarthritis, synthetic bone is commonly used as a replacement material for the opening gap. Unidirectional porous β-tricalcium phosphate (UDPTCP) and spherical porous β-tricalcium phosphate (SPTCP) have been widely used in this regard. In general, the two prostheses are placed parallel to the osteotomy opening gap. In this report, we discuss two cases involving a 63-year-old woman and a 51-year-old man who underwent MOWHTO for bilateral knee osteoarthritis. Both patients had experienced bilateral knee pain. In both patients, UDPTCP was placed anteriorly and SPTCP was placed posteriorly in one knee, with the placement reversed in the other knee. The remodeling of each type of β-TCP was evaluated using CT immediately after the surgery and one year postoperatively. The postoperative corrective loss and clinical outcomes were also evaluated. Remodeling with β-TCP was found to be faster with UDPTCP than with SPTCP, even though the anteroposterior placement differed laterally in each patient. Furthermore, there was no correction loss, and the clinical outcomes were comparable, regardless of the placement of β-TCP.

Unidirectional porous beta-tricalcium phosphate as a potential bone regeneration material for infectious bony cavity without debridement in pyogenic spondylitis

An 81-year-old man was initially diagnosed with T11 osteoporotic vertebral fracture. The fractured vertebral body was filled with unidirectional porous beta-tricalcium phosphate (β-TCP) granules, and posterior spinal fixation was conducted using percutaneous pedicle screws. However, the pain did not improve, the inflammatory response increased, and bone destructive changes extended to T10. The correct diagnosis was pyogenic spondylitis with concomitant T11 fragility vertebral fracture. Revision surgery was conducted 2 weeks after the initial surgery, the T10 and T11 pedicle screws were removed, and refixation was conducted. After the revision surgery, the pain improved and mobilization proceeded. The infection was suppressed by the administration of sensitive antibiotics. One month after surgery, a lateral bone bridge appeared at the T10/11 intervertebral level. This increased in size over time, and synostosis was achieved at 6 months. Resorption of the unidirectional porous β-TCP granules was observed over time and partial replacement with autologous bone was evident from 6 months after the revision surgery. Two years and 6 months after the revision surgery, although there were some residual β-TCP and bony defect in the center of the vertebral body, the bilateral walls have well regenerated. This suggested that given an environment of sensitive antibiotic administration and restricted local instability, unidirectional porous β-TCP implanted into an infected vertebral body may function as a resorbable bone regeneration scaffold without impeding infection control even without debridement of the infected bony cavity.