New insight into the current study of high tibial osteotomy: A bibliometric analysis.

BACKGROUND: To analyze global trends in focus and funding of research related to high tibial osteotomy (HTO) and to identify the 100 most cited articles in this field. METHODS: A Web of Science search was used to identify HTO publications in English-language scientific journals from January 1967 till February 3th, 2021. Results were filtered to the 100 most cited articles by reading the abstract or full-text paper. Information of these articles was recorded for further analysis. The 10 top-cited articles during the last 5 years and the 10 top-cited articles about HTO ranked by average citations per year were selected to predict research trends. RESULTS: In all, 48 out of the 100 top-cited articles were published between 2000 and 2010. The United States of America was the primary contributor (n = 29) followed by Germany (n = 17) and Japan (n = 11). The total number of citations per article ranged from 65 to 563, median 108, mean 135 (standard deviation = 84). The American Journal of Bone and Joint Surgery accounted for 23 out of the 100 top-cited articles. Koshino T was the most cited author (603 citations). The most frequently highlighted study theme was prognostic research. Patient-based clinical research was the dominant study design (85%). The majority of articles (48 out of 100) were level IV evidence with a mean of 141 (standard deviation = 97) citations. Top-cited articles in the last 5 years focused on open wedge osteotomy. CONCLUSION: Technical optimization of open wedge osteotomy has emerged as the main area of research in HTO. More specifically, recent publications focus on the surgical technology, cartilage repair and new fixation devices. Besides, papers with a high level of evidence are needed for the development of HTO.

Porous titanium particles for acetabular reconstruction in total hip replacement show extensive bony armoring after 15 weeks. A loaded in vivo study in 10 goats.

BACKGROUND AND PURPOSE: The bone impaction grafting technique restores bone defects in total hip replacement. Porous titanium particles (TiPs) are deformable, like bone particles, and offer better primary stability. We addressed the following questions in this animal study: are impacted TiPs osteoconductive under loaded conditions; do released micro-particles accelerate wear; and are systemic titanium blood levels elevated after implantation of TiPs? ANIMALS AND METHODS: An AAOS type-III defect was created in the right acetabulum of 10 goats weighing 63 (SD 6) kg, and reconstructed with calcium phosphate-coated TiPs and a cemented polyethylene cup. A stem with a cobalt chrome head was cemented in the femur. The goats were killed after 15 weeks. Blood samples were taken pre- and postoperatively. RESULTS: The TiP-graft layer measured 5.6 (SD 0.8) mm with a mean bone ingrowth distance of 2.8 (SD 0.8) mm. Cement penetrated 0.9 (0.3-1.9) mm into the TiPs. 1 reconstruction showed minimal cement penetration (0.3 mm) and failed at the cement-TiP interface. There were no signs of accelerated wear, metallic particle debris, or osteolysis. Median systemic titanium concentrations increased on a log-linear scale from 0.5 (0.3-1.1) parts per billion (ppb) to 0.9 (0.5-2.8) ppb (p=0.01). INTERPRETATION: Adequate cement pressurization is advocated for impaction grafting with TiPs. After implantation, calcium phosphate-coated TiPs were osteoconductive under loaded conditions and caused an increase in systemic titanium concentrations. However, absolute levels remained low. There were no signs of accelerated wear. A clinical pilot study should be performed to prove that application in humans is safe in the long term.

Better primary stability with porous titanium particles than with bone particles in cemented impaction grafting: an in vitro study in synthetic acetabula.

AIMS: Impaction bone grafting creates new bone stock after hip joint replacement. Utilizing a synthetic bone substitute instead of bone might increase primary stability and is not associated with graft shortage and pathogen transmission. This study compares the initial stability of a graft layer of porous titanium particles (TiP), cancellous bone particles, and a 1:2 bone-titanium mix in synthetic cemented acetabular reconstructions. Displacement was measured by radiostereometric analysis after cyclic loading (1 Hz, maximum stress 2.5 MPa). Shear stress resistance was quantified by a lever out test of the cup. Cement penetration was quantified from cross-sections. FINDINGS: Titanium reconstructions showed less residual displacement (0.13 ± 0.13 mm) than pure bone particle reconstructions (0.57 ± 0.18 mm) (p < 0.01). Titanium reconstructions were also more resistant to shear stress (p < 0.001). The bone-titanium mix showed intermediate results. Cement penetrated deeper into the bone particle graft layers (4.8 ± 0.7) than into the titanium graft layers (3.8 ± 0.5 mm) (p < 0.02). CONCLUSIONS: Cemented acetabular revision reconstructions with porous TiP show better initial stability despite less cement penetration than bone particle reconstructions. Realistic preclinical in vivo testing should explore the hypothesis that porous TiP offer a safe alternative to the current gold standard of bone grafts.

Osteoconduction of impacted porous titanium particles with a calcium-phosphate coating is comparable to osteoconduction of impacted allograft bone particles: in vivo study in a nonloaded goat model.

AIMS: Impaction grafting restores bone defects in hip arthroplasty. Defects are reconstructed with bone particles (BoP) as substitute materials with adequate mechanical and biological properties are not yet available. Ceramic particles (CeP) have mechanical drawbacks as opposed to porous titanium particles (TiP). In this in vivo study, bone ingrowth and bone volume in coated and noncoated TiP were compared to porous biphasic calcium-phospate CeP and allograft BoP. Coatings consisted of silicated calcium-phosphate and carbonated apatite. Materials were implanted in goats and impacted in cylindrical defects (diameter 8 mm) in the cancellous bone of the femur. On the basis of fluorochrome labeling and histology, bone ingrowth distance was measured at 4, 8, and 12 weeks. Cross-sectional bone area was measured at 12 weeks. FINDINGS: TiP created a coherent matrix of entangled particles. CeP pulverized and were noncoherent. Bone ingrowth in TiP improved significantly by the coatings to levels comparable to BoP and CeP. Cross-sectional bone area was smaller in CeP and TiP compared to BoP. CONCLUSIONS: The osteoconductive properties of impacted TiP with a calcium-phosphate coating are comparable to impacted allograft bone and impacted biphasic ceramics. A more realistic loaded in vivo study should prove that coated TiP is an attractive alternative to allograft bone.

The effect of impaction and a bioceramic coating on bone ingrowth in porous titanium particles.

BACKGROUND AND PURPOSE: Porous titanium (Ti) particles can be impacted like cancellous allograft bone particles, and may therefore be used as bone substitute in impaction grafting. We evaluated the effect of impaction and of a thin silicated biphasic calcium phosphate coating on osteoconduction by Ti particles. METHODS: The bone conduction chamber of Aspenberg was used in goats and filled with various groups of coated or uncoated small Ti particles (diameter 1.0-1.4 mm). Impacted allograft bone particles and empty chambers were used in control groups. Fluorochromes were administered at 4, 8, and 12 weeks. Maximum bone ingrowth distance was evaluated by histomorphometric analysis. RESULTS: Histology of Ti particle graft cylinders showed a dense matrix with narrow inter-particle and intra-particle pores (< 100 µm), occluding the lumen of the bone chamber. Bone ingrowth distances gradually increased with time in all groups. Maximum bone ingrowth distance was higher in originally empty chambers than those with allograft bone particles (p = 0.01) and Ti particles (p < 0.001). Maximum bone ingrowth in allograft bone particles was higher than in all Ti groups (p ≤ 0.001). Impaction reduced osteoconduction and the coating partially compensated for the negative effect of impaction, but these differences were not statistically significant. No osteolytic reactions were found. INTERPRETATION: Osteoconduction in the bone conduction chamber was reduced more by the insertion of small Ti particles than by insertion of small allograft bone particles. The osteoconductive potential of porous Ti particles should be studied further with larger-sized particles, which may allow bone ingrowth after impaction through larger inter-particle pores.