Primer Total Kalça Protezi Sonrası Protez Kalça Çıkığına Baş Çapının Etkisi
Özet
Recent advances in polyethylene and ceramic
technologies has allowed us to use larger size heads without compromising the wear
properties of a THR. One benefit of this change has been proposed to be a lower
incidence of dislocation. We retrospectively evaluated the dislocation rate in 913
THR’s performed using the same standardized surgical technique employed by a
single team of surgeons at our institution between 1995 and 2015. Patients were
assigned to two groups: small (28 mm and smaller) (SH), large diameter heads (36 mm
and larger) (LH). The cup position was measured and plotted to determine its status
according to the Lewinnek safe zone (15°±10° for anteversion, 40°±10° for
inclination). Sixteen of the 472 SH dislocated (3,4 percent) while 5 of the 441 LH
group (1,1 percent) (P=0,04). In all of the LH patients that dislocated the cup position
was in the safe range of Lewinnek. However, in the LH group only 65 percent of the
cups were in the safe zone. Using the same surgical approach by changing the head
size to 36 mm and larger, we were able decrease the dislocation rate significantly.
Errors of cup positioning according to Lewinnek became oblivious when using large
heads compared to small heads. In our opinion, using large heads in total hip
arthroplasty makes a difference in terms of dislocation.