Cemented revision in type I defects

Background

Acetabular bone loss is a technical challenge encountered at the time of revision total hip arthroplasty (THA). The severity of bone loss can be diverse, ranging from minimal deformities with intact columns (Paprosky type I) to complete loss of bony contact between the superior and inferior halves of the acetabulum, with superomedial cup migration (pelvic discontinuity, Paprosky type IIIB).

Paprosky type I acetabular defects can be found not only in the setting of revision THA but also in several complex primary THAs. Usually, such defects arise after the explantation of a cementless cup that had not been fully medialized or after retrieval of a well fixed cemented cup, in which an overall slight cavitary defect is associated with small well-delineated deficiencies at the level of the cement holes. In these cases, the remaining anterosuperior and posteroinferior columns provide structural support for a new acetabular component, which can be either cementless or cemented.

Though the popularity of cementless acetabular components in primary THA has been on the rise in the last three decades, survival data from national joint registries have demonstrated excellent clinical results for cemented cups. ^, A meta-analysis that compared survivorship between cementless and cemented acetabular components in primary THA showed that the logistic regression model of the pooled data revealed an estimated odds ratio of 1.49 (95% CI, 0.7 to 3.17) for the survival of a cemented acetabular component compared to a cementless component. Additionally, a recent observational study of 22,956 patients registered at the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) indicated that cemented THA has excellent survivorship at 15 years of follow-up, and such survivorship is further improved if surgeons perform at least 25 cases/year. Although concerns regarding component loosening have discouraged arthroplasty surgeons from using cemented acetabular components in primary THA, this fixation technique has been shown to be more reliable than cementless fixation beyond the first ten postoperative years of follow-up.

In this scenario, contained acetabular defects with minimal bone loss (i.e., Paprosky type I defects) can be successfully revised with a cemented (primary or dual mobility) acetabular component. Premise: this technique requires the presence of cancellous bone appropriate for cement interdigitation ( Fig. 5.1 ) ; if sclerotic bone is encountered, it is suggested to ream (if feasible) or to use the impaction bone grafting (IBG) technique to enhance cement fixation. This will enhance the long-term durability of an all-polyethylene cemented cup. ^,

In the authors’ institution, acetabular revision with a cemented component is currently infrequent; however, they indicate its use mostly in the setting of chronic periprosthetic joint infection treated with one-stage revision THA (only in cases with appropriate acetabular bone stock). Additionally, the authors have indicated this procedure for cases of early acetabular component loosening (in which osseointegration of a cementless component did not occur).

Surgical technique