If an osteotomy is carried out in the plane of deformity, it allows correction of the deformity by rotating the opposing bone surfaces while maintaining maximum bone contact.
This system classifies the absence of heterotopic bone formations as grade 0, the presence of islands of bone within the soft tissues of the treated hip as grade I, the occurrence of bone spurs and a gap between opposing bone surfaces of >1 cm as grade II, the presence of bone spurs and a gap of <1 cm as grade III, and a bridge of bone across the joint as grade IV.
The 2 opposing bone defects on either side of the calvaria were filled with 0.701 (SD 0.005) g autograft per 0.785 cm bone defect.
The tibial tubercle segment is required to be of adequate size to facilitate secure hardware fixation and provide a wide contact area between the opposing bone surfaces.
The diarthrodial joints join two opposing bone surfaces that are covered by a specialized hyaline cartilage providing a low-friction, articulating interface.
The most serious type of ankylosis is that in which the synovial membrane and cartilage both have disappeared and in which osseous union has taken place between the opposing bone ends.
Recent mechanical simulation studies have confirmed higher intra-osseous stress values beneath the joint surface when the amount of overlying cartilage is diminished [ 17], which could also lead to SBC formation in the opposing bone in the joint.
Like estrogen, tamoxifen opposes bone turnover (albeit to a lesser degree [ 20]), and thus suppression of bone turnover by tamoxifen or estrogen may limit the magnitude of benefit accruing from ZA treatment because ZA has a greater survival benefit in patients with bone metastases with high basal levels of bone turnover [ 21].
The chondrocytes then form the cartilage at the end of the opposing bones with the intervening interzones formed during cavitation or they undergo proliferation, terminal differentiation to chondrocyte hypertrophy, and apoptosis in a process termed endochondral ossification, whereby the hypertrophic cartilage is replaced by bone.
However, bone evaluation techniques generally assess bone quantity as opposed to bone quality.
