Calcium phosphate cement enhances primary stability of open-wedge high-tibial osteotomies

Abstract

We investigated if injectable calcium phosphate cement improves primary stability in open-wedge high-tibial osteotomy. A 10 mm open-wedge osteotomy was performed on eight pairs of preserved cadaver tibiae and seven pairs of composite (Sawbone) left tibiae. Osteosynthesis was performed with the Dynafix plate system. The gap resulting from surgery either was filled with 15 g injectable calcium phosphate cement in half the bones or was left untreated. The composite tibiae were loaded at a ramp speed of 20 mm/min up to 20 kN. The cadaver tibiae were exposed to 100 cycles with a maximum compressive force of 2,250 N. After 100 cycles of loading with 2,250 N, the final loaded displacement was 1.2 mm for the cadaver tibiae treated with injectable calcium phosphate cement as compared with 3.6 mm for the empty defects (P = 0.028). All the seven empty defect composite specimens failed prior to 20 kN (median 2.8 kN) as compared with five of the injectable calcium phosphate cement specimens (median 17 kN) (P = 0.005). The injection of injectable calcium phosphate cement following open-wedge osteotomy of the proximal tibia increases the initial stability of the bone as measured by load-to-failure and displacement after cyclic loading. Clinical studies are ongoing to investigate whether injectable calcium phosphate cement also has clinical advantage on wedge healing and stability.

Open-Wedge High Tibial Osteotomy: RCT 2 Years RSA Follow-Up

“…However, we did also find that the implant itself seemed to be stable enough to withstand the loadings found during walking. 16 This might be the reason why the migration in the two bone graft groups also was small in the present study. The patients were aligned to 4 degrees of valgus and kept the alignment throughout the study period.…”

Biocompatibility of calcium phosphate bone cement with optimized mechanical properties

“…Merck‐CPC was formulated from a powder phase of 61% α‐TCP, 26% calcium phosphate (CaHPO 4 ), 10% calcium carbonate (CaCO 3 ), and 3% hydroxyapatite (Plasma Biotal, Derbyshire, UK) and a liquid phase of 4 wt % di‐sodium hydrogen phosphate (Na 2 HPO 4 ) (Fisher Scientific, Leicestershire, UK) in deionized water mixed at a liquid‐to‐powder ratio of 0.35 mL/g. It is based on a commercial formulation developed by Merck KGaA (Darmstadt, Germany) to have a similar chemical composition and crystalline structure with that of the mineral phase of bone . The PMMA cement used was Vertebroplastic Radiopaque Resinous Material (DePuy, Leeds, UK), which is a commercially available cement routinely used clinically for vertebroplasty (referred to herein as VP‐PMMA).…”

“…It is based on a commercial formulation developed by Merck KGaA (Darmstadt, Germany) to have a similar chemical composition and crystalline structure with that of the mineral phase of bone. 37 The PMMA cement used was Vertebroplastic Radiopaque Resinous Material (DePuy, Leeds, UK), which is ORIGINAL RESEARCH REPORT JOURNAL OF BIOMEDICAL MATERIALS RESEARCH B: APPLIED BIOMATERIALS | FEB 2016 VOL 104B, ISSUE 2 a commercially available cement routinely used clinically for vertebroplasty (referred to herein as VP-PMMA).…”

Calcium phosphate cement enhances the torsional strength and stiffness of high tibial osteotomies

“…Numerous basic science papers support the concept of calcium phosphate cement as a bone graft substitute that carries osteoconductive properties utilized in both tibial plateau fracture treatment and supplementation to owHTO fixation [23, 25, 36, 37]. Biomechanical studies utilizing cadaveric tibia have shown that calcium phosphate cement provides significantly increased compressive strength and stiffness compared to autograft iliac bone graft [25, 37].…”

“…Biomechanical studies utilizing cadaveric tibia have shown that calcium phosphate cement provides significantly increased compressive strength and stiffness compared to autograft iliac bone graft [25, 37]. In particular, Lind‐Hansen et al [23] demonstrated in cadaver tibiae that the injection of calcium phosphate cement increases the initial stability of high tibial osteotomy fixation when the specimens were loaded in compression. To date, only one other study has identified torsional load as an important variable after owHTO [35], but rotational forces are placed on the knee during a normal gait cycle, which is therefore an important aspect of construct design for an ambulatory patient after owHTO [12].…”