The problem faced by the surgeon that Tan et al. address is the dilemma about what to do when a patient has a worn-out liner in a well-fixed cup. Usually, this situation is seen in a patient with an index total hip replacement that was done before the year 2000. (After that date most were done with highly cross-linked polyethylene liners, which usually show little wear at less than fifteen years.) If a highly cross-linked polyethylene replacement liner is not available for the cup in question or if the locking mechanism has failed, what does the surgeon do? Extract the cup or cement the liner? Heck and Murray first described the idea of cementing a new liner into a well-fixed shell in 1986. This option is attractive in that it can be done quickly with minimal blood loss and morbidity. Ever since they described the idea, however, there have been questions as to the durability of the resulting construct. Fortunately, there have been several studies describing the biomechanical testing of this technique, as well as several mid-term studies of the clinical cases.

The present study provides a longer-term (two to nineteen-year) clinical look at a previously published series of thirty-two hips in thirty patients. Unfortunately for critical analysis, nearly half of these new liners were metal. It is understandable that Tan et al. chose to use metal liners at the time these cases were performed. Metal-on-metal total hip replacements were thought back then to perhaps be superior with respect to longevity in younger patients (and the average age in the study was only 53.7 years). Now that metal-on-metal bearings have been shown to be inferior, it would not be a choice one would make today. I do not believe we can assume that the construct that involves cementing a metal liner can be equated to cementing a polyethylene liner. Regardless, the failures of cement fixation are few in this longer-term study (only two of thirty-two hips). Perhaps this is a moot point, but it does reduce an already small series to only seventeen polyethylene liners.

The survivorship rates, with revision for any reason as the end point, at five, ten, and fifteen years in this study were 86%, 77%, and 69%. This is not quite as good as the results of revisions with cementless acetabular components. However, only five hips (16%) required reoperation for failure of the acetabular construct, and those occurred in a series of younger, active patients. In an elderly population with less activity and fewer years of life remaining, the survivorship can be expected to be better. Tan et al. recommended that liner cementation into a stable retained shell be reserved for just this population.