Early intraprosthetic dislocation in dual-mobility implants: a systematic review

Abstract

BackgroundDual mobility implants are subject to a specific implant-related complication, intraprosthetic dislocation (IPD), in which the polyethylene liner dissociates from the femoral head. For older generation designs, IPD was attributable to late polyethylene wear and subsequent failure of the head capture mechanism. However, early IPDs have been reportedly affecting contemporary designs.MethodsA systematic review of the literature according to the preferred reporting items for systematic reviews and meta-analyses guidelines was performed. A comprehensive search of PubMed, MEDLINE, Embase, and Google Scholar was conducted for English articles between January 1974 and August 2016 using various combinations of the keywords “intraprosthetic dislocation,” “dual mobility,” “dual-mobility,” “tripolar,” “double mobility,” “double-mobility,” “hip,” “cup,” “socket,” and “dislocation.”ResultsIn all, 16 articles met our inclusion criteria. Fourteen were case reports and 2 were retrospective case series. These included a total of 19 total hip arthroplasties, which were divided into 2 groups: studies dealing with early IPD after attempted closed reduction and those dealing with early IPD with no history of previous attempted closed reduction. Early IPD was reported in 15 patients after a mean follow-up of 3.2 months (2.9 SD) in the first group and in 4 patients after a mean follow-up of 15.1 months (9.9 SD) in the second group.ConclusionsBased on the current data, most cases have been preceded by an attempted closed reduction in the setting of outer, large articulation dislocation, perhaps indicating an iatrogenic etiology for early IPD. Recognition of this possible failure mode is essential to its prevention and treatment.

Early Recurrent Dislocation and Dissociation of Bipolar Cup: Two Intricate Cases and Review of Literature.

“…Routine closed reduction of a dislocated bipolar component is more di cult than that of a conventional THA because of the larger diameter of the outer cup. Closed reduction techniques should be performed with satisfactory analgesia and muscle relaxation [7,16]. Although closed reduction was attempted in all patients, only 30 percent of patients were managed to avoid additional surgery [4,17].…”

Dislocation of the Hip: A Review of Types, Causes, and Treatment

“…33 Dual-mobility implants were introduced in the United States in 2009. 36 As noted previously, these implants have a small and a large articulation that can dissociate during dislocation or a reduction attempt. IPD can occur during a reduction attempt when the larger plastic femoral head catches on the acetabulum and dissociates from the smaller head, similar to a bottle-cap effect.…”

“…When the small femoral head reaches the limit of its range of motion, the larger femoral head will then move which allows for an increased range of motion before impingement ( Figure 3A). 14,35,36 However, because of the additional bearing compared to fixed-bearing total hip replacement, a unique dislocation can occur known as an intraprosthetic dislocation (IPD) ( Figure 3B). 14,35 In an IPD, the larger polyethylene femoral head dissociates from the smaller femoral head.…”

“…14,35 In an IPD, the larger polyethylene femoral head dissociates from the smaller femoral head. 35,36 Postreduction x-rays can show what appears to be a successful reduction; however, in an IPD, the femoral head is eccentrically located in the acetabulum, and close evaluation reveals a halo in the soft tissue, representing the polyethylene that has dissociated ( Figure 3B). Open revision is necessary to treat an IPD.…”

“…29 When closed reduction fails or instability persists, invasive methods include exchanging prosthetics, use of large femoral heads, use of dual-mobility implants, and/or use of constrained liners. 29,36…”