It would be a revolutionary idea to interpose unresorbable osteoconductive HA at bone and bone cement interface by expecting chemical bonding of HA with bone and osteoconduction forever to prevent radiolucent line and loosening. As a surgical procedure, less than two layers of HA granules of 300 to 500 micron in diameter were smeared on the bone surface just before the cement insertion (Interface Bioactive Bone Cement : IBBC). In animal experiments, at one week, bone ingrowth began into one to two layers of HA granules. At two to three weeks, bone ingrowth completed. The bonding strength in the case of IBBC without anchor holes at six weeks attained to 50% of non-IBBC and IBBC with anchor holes and showed the same tendency as HA coating on the smooth surface. In clinical cases, the majority of HA granules were incorporated into dense cortical bone and cancellous bone connected to adjacent dense cortical bone and cancellous bone, respectively. The shape and sizes of HA granules were not changed at 17 years. In conventional bone cement (Non-IBBC) and cementless fixation, the spaces will appear at the bone interface due to aging of bone. As unresorbable crystalline HA is used in IBBC and HA is osteoconductive, at present enduring osteoconduction could be expected in only IBBC.
We have used HA granules in acetabular massive bone defect in revision THA since 1985. Because as HA is osteoconductive and crystal HA is not resorbable, new bone formation will continue forever. In clinical cases, porous HA granules were filled densely into massive acetabular bone defects under weight bearing condition. Whole HA granule masses of approximately 2.0 and 2.5 cm in thickness were retrieved at revision THA. Non-decalcified specimens were observed. As a control, in non-weight bearing condition, HA granules were filled densely into the cavity made at the proximal end of the tibia of mature goats. At one year and six months the goat was sacrificed. It was very difficult to drill into the HA granule mass and to cut the mass with a chisel. A large amount of bone ingrowth from the acetabulum were found in the whole spaces. In a control a large amount of bone ingrowth were obtained into the spaces only at the peripheral area of the cavity to approximately 5 mm in depth. A large amount of bone growth to the deep area can be expected in weight bearing areas. However, in non-weight bearing areas, it can't be expected.
Less than two layers of HA granules (100-300µm or 300-500 µm) were smeared onto the bone surface just before the cement fixation of the components. Care was taken to implant the components under complete hemostasis. The patient group comprised 268 THAs in 232 patients performed with this cementing technique between 1987 and 1989. Six acetabular components were defined as radiologically loose and one hip was revised at 7 years after the operation. Overall, radiological loosening rate for acetabular component was 2.6%. No femoral component was defined radiologically loose. On the dense bone, new dense bone grew into the spaces of HA particles and new dense bone layers were formed by new bone and HA particles. On the cancellous bone, new cancellous bone layers were formed by new cancellous bone and HA granules as well. In IBBC, as HA is osteoconductive and bone ingrowth into HA granules is obtained, even if bony atrophy or osteoporosis occurs long terms after surgery, bone ingrowth will continue forever and no RLL will not appear.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.