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

Isolated acetabular cup revision in Metal-on-Metal total hip arthroplasty: a low-complication strategy feasible in only half of cases

PURPOSE

There is still a debate regarding the removal of the femoral stem due to the risk of trunnion. To answer this question, we conducted a study to compare long terms outcomes of isolated acetabular to total revision of MoM THA using an institutional arthroplasty registry.

METHODS

From 1996 to 2019, 150 patients (12.5%) of the 1202 revision THAs (rTHA) recorded in Geneva Arthroplasty Registry (GAR) underwent a revision of a MoM THA. After matching the two groups,126 patients were finally included: 63 in each group. The mean age was 64.4 (SD 11.6) years, 48.4% (61/126) were women with a mean BMI of 27.2 (SD 5.5) Kg/m2.

RESULTS

The overall survival rate was 88.1% [79.9-97.2%] at ten years. 10-year survival rate was 93.5% [86.2-100.0%] after isolated acetabular rTHA and 79.5% [61.7-100.0%] after total rTHA (p = 0.16). Regarding Hip Harris score and Merle d'Aubigne score, no difference at last follow-up was observed between the two groups (respectively: p = 0.39; p = 0.33). Regarding the chrome, cobalt, and nickel level reduction, no difference was observed between the two groups (respectively, p = 0.38, 0.81 and 0.97).

CONCLUSION

No difference was observed between isolated acetabular and total revision of MoM THAs regarding survival rate and ions levels at long term. It seems advisable to perform an isolated acetabular revision of a MoM THA when it is indicated.

LEVELS OF EVIDENCE

Level III, case control studies.

Dual-mobility tripod cup for revision hip arthroplasty: long-term (five to fourteen years) evaluation of a new generation cementless implant

PURPOSE

The aims of this study were to evaluate the survivorships of a new generation cementless DMC with tripod additional fixation in revision total hip arthroplasty and complications at a minimum five year follow-up.

METHODS

One hundred and fifteen revisions (THA) treated with tripod DMC performed between 2009 and 2015 were included in this retrospective study. Acetabular defects were classified as Paprosky 1 (n = 38, 33%), 2 (n = 75, 65%) or 3 (n = 2, 2%). Unipolar or bipolar revision was performed for the following indications: aseptic acetabular loosening (63%), infection (14%), aseptic bipolar loosening (11%), instability (4%), aseptic femoral loosening (3%), ALVAL (3%) and iliopsoas impingement (2%). Mean follow-up was 9.4 years ± two (range, 5 to 14).

RESULTS

At the final follow-up, a single episode of dislocation occurred within three months after the procedure (0.8%) with no revision. Three cases of aseptic loosening were diagnosed (2.6%). Four infections (3.5%) required reoperation: three required a two stage bipolar revision; one was treated by DAIR procedure. At the latest follow-up, the survivorship of the acetabular cup for aseptic loosening was 98% [95% CI (91.2-99.4)] and for any reasons was 94.4% [95% CI (90.1%-98.9%)]; the mean HHS improved from 60 points (range, 18-94 points) to 83 points (range, 37-100 points) (p < .001).

CONCLUSION

This study reports a low complication rate in favour of the use of a tripod DMC in revision THA with a satisfactory survivorship at a ten year follow-up.