Total hip dislocation is common and is associated with femoral head roughening. Low-friction ion treatment hardens the surface of femoral heads and may protect against surface damage from dislocation.Methods:
Retrieved low-friction ion treated femoral heads with prior dislocation (n=14) were evaluated for surface roughness (Ra), mean peak height (Rpm) distance from peak to valley (Rmax), deepest valley from the mean surface line (Rv) by using a contact profilometer, and values were compared with previously published control values of nondislocated heads (n=46).Results:
The maximal surface roughness was significantly greater than controls for the dislocated heads (P=0.039). Rpm (P=0.11), Rmax (P=0.16) Rv (P=0.16), average Ra (P=0.068), average Rpm (P=0.16), average Rmax (P=0.22), and average Rv (P=0.23) were not significantly greater for dislocated heads compared with nondislocated heads. Each of these values, however, was greater for the dislocated head group, despite a shorter time in vivo (1786 days compared with 2322 days). Scanning electron microscopy and element analysis, used to further characterize surface irregularities in select dislocated heads, confirmed that the higher roughness values of dislocated heads were caused not only by scratching but also titanium (Ti) smeared on the head surface.Conclusions:
Dislocated heads have localized roughening when compared with nondislocated heads, and this occurs despite ion treatment.