Cementation of a dual‐mobility acetabular component into a well‐fixed metal shell during revision total hip arthroplasty: A biomechanical validation

Abstract

Cementation of polyethylene (PE) liners into well-fixed metal shells has become a popular option during revision total hip arthroplasty (THA) particularly for older and frail patients. Although dramatic results were reported with dual-mobility acetabular components to manage hip instability during revision THA, no study evaluated the fixation strength of the cementation of dual-mobility components into well-fixed metal shells. Eight dual-mobility and eight all-PE components were cemented into a metal shell with a uniform 2-to 3-mm cement mantle. The cemented fixation strength was evaluated using lever-out and torsion testing. The interface at which failure occurred was determined. Lever-out testing showed that dual-mobility components failed at significantly higher maximum moment than the all-PE components. No direct comparison could be performed with torsion testing due to early failure of the all-PE component itself before failure of the cement fixation. However, the maximum moments measured were dramatically higher than the in vivo frictional moments classically reported in THA. In addition, failure was always observed at the metal shell/cement interface whenever it did occur. In conclusion, a dual-mobility acetabular component cemented into a well-fixed metal shell could constitute a biomechanically acceptable alternative to acetabular shell removal or PE liner cementation while simultaneously preventing instability of the THA revision. Clinical studies are warranted. Keywords: revision total hip arthroplasty; dual-mobility acetabular component; cement; fixation strength; instability Despite continuous improvements in surgical technique and implant design, the rate of revision total hip arthroplasty (THA) did not decrease over the past few decades.1 Furthermore, with increased life expectancy of THA patients and a trend toward surgical indication at younger ages, demand for THA revisions is projected to double by 2026, and case complexity is likely to increase dramatically.2 Instability constitutes the major indication for THA revision, is the most common reason for failure after revision, and represents the most common reason for isolated acetabular revision and modular component exchange.1,3 Modular component exchange has been proposed in an attempt to manage THA instability while minimizing potential morbidity due to extensive bone loss, intra-operative bleeding, and prolonged operative time accompanying formal revision procedures, particularly for older and frail patients. 4,5 Beside instability management, modular component exchange could be required in cases of wear or mechanical failure of the liner. However, liner replacement may be impossible or impractical due to damaged locking mechanisms compromising liner fixation, incompatibility of the available components, non-modularity of the metal shell, or sub-optimal positioning of the acetabular component requiring reorientation. Previous biomechanical and short-term follow-up clinical studies reported the cementation of polyethylene (PE) line...

Rapid return to function and stability with dual mobility components cemented into an acetabular reconstructive cage for large osseous defects in the setting of periacetabular metastatic disease

“…Obtaining stable implant fixation and ultimately functional improvement remains a difficult challenge in patients with large osseous acetabular defects secondary to periacetabular metastatic disease. Dual mobility bearings provide greater ROM, a greater head‐to‐neck ratio, and a physiologic head size ultimately offering greater resistance to dislocation Our findings are similar to other studies showing patients treated, by cementing dual mobility cups into an acetabular cage, with this technique are able to return to full ambulatory status and have low rates of dislocation and or revision …”

“…One pack of polymethylmethacrylate bone cement was used to cement a dual mobility liner (Modular Dual Mobility Hip Bearing System‐MDM; Stryker) into the acetabular cage. The MDM liners were cemented in approximately 20° of anteversion and 40° of abduction with equal cement distribution around the liner . A cemented femoral component was utilized in all cases, including 17 Omnifit EON femoral stems, one GMRS Proximal Femoral Replacement, and one Accolade femoral stems (Stryker Orthopaedics) .…”

Revision Total Hip Arthroplasty in the Setting of a Well-Fixed Cup: Early Report on the Cup-in-Cup Technique

“…While our early clinical measures are promising, longer follow-up is needed to determine if cement debonding and loosening risks increase as loading and torsional stresses accumulate over time from the longer moment arm created by increasing leg length and offset. 14,20 In cases of acetabular component malposition, the cup-incup construct can be used selectively in cases where substantial retroacetabular bone loss exists, and cup explantation would cause imminent discontinuity and/or drastically alter the surgeon's ability to reconstruct the socket due to loss of superomedial support. Previously placed cups in a neutral orientation or mild retroversion (no more than 10°) are not necessarily excluded as long as they meet the minimum dimensions requirement, and the degree of their malposition does not cause further impingement when the new inner cup is placed in the targeted position (►Fig.…”

“…[9][10][11][12] Two biomechanical validation studies have supported the potential utilization of cementing an all-metal porous cup into an acetabular shell when compared with cementing in a polyethylene liner, consistently citing higher lever-out thresholds when the version added was 20 degrees or less. 13,14 To avoid issues of creating large acetabular defects in the setting of a failed total hip with a well-fixed cup, we have managed a select group of patients with instability by cementing in smaller, porous shell into the original acetabular component. In theory, this avoids incurring large acetabular defects, allows for an increase in leg length and restoration of offset, and provides improved cement interdigitation into the porous surface of the shell versus cementation of a polyethylene insert.…”

Revision of Metal-on-metal Hip Arthroplasty with Well Fixed and Positioned Acetabular Component Using a Dual-mobility Head and Review of Literature

“…Other possibilities to preserve well positioned monoblock acetabular component were to cement of an unconstrained tripolar implant into an acetabular component [28, 29]. …”