Allograft Bone Dowel Incorporation to Tibial and Femoral Tunnels in Two–Stage Revision Anterior Cruciate Ligament Reconstruction (173)

Objectives: The purpose of this study was to quantitatively evaluate the radiographic outcomes of allograft dowels used as bone grafts in two-stage revision anterior cruciate ligament reconstruction (ACLR). Methods: Prospective review of patients who underwent 2-stage revision ACLR with allograft bone dowels. Inclusion criteria were tibial/femoral tunnel diameter of >14 mm on pre-operative computed tomography (CT), overlapping prior tunnels with new tunnels (Figure 1). Allograft dowels were placed during the first stage and arthroscopic assessment of dowels was performed at the second-stage revision (Figure 2). Quantitative analysis of radiographic incorporation rates was performed with the Union Ratio (UR, Figure 3A) and Occupying Ratio (OR, Figure 3B) on post-operative CT scans. Biopsy specimens were obtained to analyze incorporation. Results: 21 patients were included. Second-stage revision surgeries were performed at 6.5 months (SD, 2.1 months) after first-stage revision. All dowels preserved their integrity without any signs of degradation and complete incorporation at the host bone and graft junction at the second stage procedure. The average diameter of the dowels placed in tibial tunnels were greater than those placed in femoral tunnels (16.1 mm [SD, 2.3 mm] vs 12.4 mm [SD, 1.6 mm]; p = < .05). CT scans were obtained at 121 days (SD, 28 days) after the first-stage. There was no difference between the OR of femoral and tibial tunnels (87.6% [SD, 4.8%] vs 85.7% [SD, 10.1%]; p = .484), however, the UR was significantly higher in femoral tunnels (74% [SD, 10.5%] vs 83%[ SD, 6.2%], p = 0.005). Histological examination revealed osseous incorporation between the host bone and allograft dowel (Figure 4). Conclusions: Allograft bone dowels are a safe graft choice to replenish bone stock in the setting of a staged revision ACL reconstruction and dowels placed in femoral tunnels had a higher healing union ratio. Further studies are warranted to evaluate long-term clinical outcomes in this subset of patients.

Recombinant human PDGF-BB in combination with mineralized freeze-dried bone allograft in the treatment of Grade II furcation involvement: A case report

Recombinant human platelet-derived growth factor-BB (rhPDGF-BB) is commercially available biomaterial that can be used to regenerate the lost periodontal structure due to progression of periodontitis. The present case describes the surgical treatment of localized periodontitis with furcation Grade II involvement using platelet-derived growth factor BB (growth-factor enhanced matrix 21S) in combination with particulate allograft bone (mineralize freeze-dried bone allograft [FDBA]).This case report showed complete furcation closure after using rhPDGF-BB in combination with FDBA to treat localized periodontitis case with Grade II furcation involvement.

Osteobiologics

BACKGROUND Osteobiologics are engineered materials that facilitate bone healing and have been increasingly used in spine surgery. Autologous iliac crest bone grafts have been used historically, but morbidity associated with graft harvesting has led surgeons to seek alternative solutions. Allograft bone, biomaterial scaffolds, growth factors, and stem cells have been explored as bone graft substitutes and supplements. OBJECTIVE To review current and emerging osteobiologic technologies. METHODS A literature review of English-language studies was performed in PubMed. Search terms included combinations of “spine,” “fusion,” “osteobiologics,” “autologous,” “allogen(e)ic,” “graft,” “scaffold,” “bone morphogenic protein,” and “stem cells.” RESULTS Evidence supports allograft bone as an autologous bone supplement or replacement in scenarios where minimal autologous bone is available. There are promising data on ceramics and P-15; however, comparative human trials remain scarce. Growth factors, including recombinant human bone morphogenic proteins (rhBMPs) 2 and 7, have been explored in humans after successful animal trials. Evidence continues to support the use of rhBMP-2 in lumbar fusion in patient populations with poor bone quality or revision surgery, while there is limited evidence for rhBMP-7. Stem cells have been incredibly promising in promoting fusion in animal models, but human trials to this point have only involved products with questionable stem cell content, thereby limiting possible conclusions. CONCLUSION Engineered stem cells that overexpress osteoinductive factors are likely the future of spine fusion, but issues with applying viral vector-transduced stem cells in humans have limited progress.

Single-stage posterior-only debridement, decompression and interbody fusion for the treatment of thoracolumbar spinal tuberculosis complicated with psoas abscesses

Background To explore the clinical safety and efficacy of single-stage posterior-only debridement, decompression, allograft bone using titanium mesh and interbody fusion combined for the treatment of thoracolumbar spinal tuberculosis complicated with psoas abscesses. Methods A total of 38 patients diagnosed with thoracolumbar spinal tuberculosis complicated with psoas abscesses underwent surgery via single-stage posterior-only debridement, decompression, allograft bone using titanium mesh and interbody fusion from January 2010 to September 2016 were enrolled in the study. The clinical efficacy of the approach was assessed based on parameters including operating time, blood loss, Cobb angle, visual analogue scale (VAS) scores, Frankel grade, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Results The surgery duration was 224.4 ± 71.1 min with a blood loss of 731.8 ± 585.8 ml. The Cobb angle was corrected from 16.0 ± 15.4° preoperatively to 8.1 ± 7.4° postoperatively (P < 0.001, t = − 4.38), and returned to a level of 11.0 ± 8.5° at the final follow-up (P = 0.002, t = 3.38). Back pain was relieved, with the mean preoperative VAS of 3.5 ± 1.1 decreased to 0.7 ± 0.8 postoperatively (P < 0.001, t = 23.21) and then to 0.6 ± 0.5 at the final follow-up (P < 0.001, t = 17.07). Neurological function was improved in various degrees and psoas abscesses disappeared in all patients. The ESR and CRP decreased gradually after surgery and returned to normal at the final follow-up in all patients. All patients achieved bone fusion thoroughly and no recurrence of TB or surgical related complications was found at the final follow-up. Conclusion Single-stage posterior-only debridement, decompression, allograft bone using titanium mesh and interbody fusion is a safe and effective approach for the management of thoracolumbar spinal tuberculosis complicated with psoas abscesses.