Total Hip Arthroplasty Using a Hemispherical Uncemented Dual-Mobility Cup Results in Satisfactory Clinical Outcomes and No Dislocations at 2 years

Abstract

Background The authors performed total hip arthroplasty (THA) using a novel hemispherical dual-mobility (DM) acetabular cup without a protrusive cylindro-spherical rim, intended to reduce risks of iliopsoas impingement without requiring changes to conventional intraoperative positioning as with unipolar cups. We aim to determine clinical scores and rates of dislocations, complications, and revisions of this hemispherical DM cup, with the hypothesis that this novel design would result in clinical scores and dislocation rates comparable to other contemporary DM cups with protrusive cylindro-spherical rims. Methods We assessed 332 consecutive uncemented THAs performed using a hemispherical DM cup, at a minimum 2-year follow-up, using modified Harris Hip Score (mHHS) and Oxford Hip Score (OHS), and noting complications and revisions. Regression analyses were conducted to determine if mHHS and OHS depended on any independent factors. Results At 2.8 ± 0.5 years (range, 2–5), 2 patients (0.6%) had stem and cup revisions, 3 patients (1%) had isolated stem revisions, 13 patients (4%) died, and none were lost to follow-up. No dislocations occurred. For the final cohort of 305 patients (314 hips) with their original implants in place, mHHS was 92 ± 12 (range, 46–100), and OHS was 57 ± 5 (range, 34–60). Multivariable analyses revealed that mHHS and OHS decreased significantly with age (β = -0.35, P < .001, and β = -0.15, P < .001, respectively). Conclusions With no dislocations and satisfactory clinical scores, this sizable cohort confirms that the novel hemispherical DM cup studied is effective at preventing dislocations, although longer-term follow-up remains necessary to ascertain the longevity of clinical outcomes and radiographic stability. Level of Evidence Level IV, multicentric retrospective case series.

The use of dual mobility cups in revision total hip arthroplasty for failed large head metal-on-metal bearings

“…Soft tissue damages due to ARMD as well as potential hip abductor deficiency were systematically reported on the operative reports. A single design of true hemispherical DMC was used (Symbol®, Dedienne Santé, Mauguio, France) with a cementless press-fit fixation in 53 THA (82%) and a cemented fixation in 11 THA (18%) being cemented in the bon acetabulum in two THA (3%), in a Ganz reinforcement device in three THA(5%), in a Burch-Schneider anti-protrusion cage in one THA (2%), in a porous tantalum reconstruction shell in three THA (5%) or using a double-socket technique (cementation of dual mobility cup in well positioned existing acetabular cup) in two THA (3%) (Table 2 ).The cementless Symbol® DMC consists of a monoblock Co-Cr metal shell that is double coated with porous titanium alloy plasma spray and hydroxyapatite at the osseointegration surface without additional screwed fixation [ 17 ]. The cemented version of the Symbol® DMC was specifically designed for cementation with peripheral radial and concentric circumferential grooves for cement interdigitation [ 18 ].…”