Author's reply.

Sir,

In response to the reader's comments,1 we would like to state that we initially had the same inference from the results of our study.2 Removal of bone from the intercondylar notch area in posterior cruciate (PC)-substituting designs imparts vulnerability to the thinned out medial femoral condyle and may lead to intraoperative fractures3 but this has not been reported anywhere to predict the risk of postoperative fractures.

On exhaustive literature search, we found no definite evidence reported by any study suggesting the higher risk of delayed periprosthetic fractures with PC-substituting designs (as has been alluded to by the readers). The associations studied (and reported) have been with female sex,4 age45 (ages, 61–80 years had the highest risk), osteoporosis,5 inflammatory arthritis,5 corticosteroid use5 and revision total knee arthroplasty (TKA) surgery,45 as has been highlighted in our report.2

Interestingly, higher comorbidity scores were found to predict a higher risk of periprosthetic fracture in both primary and revision TKA, with higher risks in patients suffering from peptic ulcer disease and pulmonary disease.5

We agree with the readers’ alluded reference stating difficulties in fixation seen in locking plate fixation of very distally located periprosthetic fractures, and have recommended revision to a distal femoral replacement prostheses in these situations.2