Can Dual Mobility Cups prevent Dislocation in All Situations After Revision Total Hip Arthroplasty?

Assessment of Damage on a Dual Mobility Acetabular System

“…Despite this success, 2 dislocation modes are associated with dual mobility systems: large head dislocation and intraprosthetic dislocation (IPD), at the smaller articulation [11,12]. Rates of large head dislocation and IPD range from 0.6% to 1.5% and 0.2% to 0.28%, respectively [10,13]. …”

The dual mobility liner: Is it ready for prime time?

“…Dual mobility liners have demonstrated long term success rates in reducing issues related to post-operative instability in the literature, both in primary but particularly in the revision settings where the issue is most prevalent. In two of the largest revision studies to date, 1.7% overall instability rates over a 7.3 year follow up [15] and 5% over 7.7 years have been achieved [18]. Lombardi et al [17] compiled summary tables on both primary and revision dual mobility liners in regards to both component survival as well as dislocation rates.…”

“…The largest revision dual mobility publication to date (n=994) with 7.3 year follow up showed 2 (0.2%) intra-prosthetic dislocations which were attributed to a poor head/neck ratio with impingement occurring early in the range of motion and thus accelerated chamfer wear. In regards to the femoral neck, recommendations for using a narrow polished and smooth geometry would theoretically impart less friction/stress at the chamfer interface and minimize IPD risks [15]. Wegrzyn et al [15], the largest study to date on revision dual mobility usage (n=994) hips, prospectively followed patients for a mean of 7.3 years demonstrating 15 (1.5%) dislocations and 2 (0.2%) IPD's.…”

“…In regards to the femoral neck, recommendations for using a narrow polished and smooth geometry would theoretically impart less friction/stress at the chamfer interface and minimize IPD risks [15]. Wegrzyn et al [15], the largest study to date on revision dual mobility usage (n=994) hips, prospectively followed patients for a mean of 7.3 years demonstrating 15 (1.5%) dislocations and 2 (0.2%) IPD's. Most important to note, was that 5 of the 15 dislocations were found to be technical errors during the initial placement including, cup malposition (n=1), over shortening of the leg (n=1), and abductor mechanism fixation issues (n=3).…”

Comparison of dual-mobility cup and unipolar cup for prevention of dislocation after revision total hip arthroplasty

“…In a recent large series evaluating 994 revision THAs, a dislocation rate of 1.5% at a mean follow-up time of 7.5 years was reported (Wegrzyn et al. 2015). …”