Evaluation of the Cementation Index as a Predictor of Failure in Coonrad-Morrey Total Elbow Arthroplasty

Background. The aim of this study is to objectively evaluate the quality of cementation by a novel method called the cementation index and assess its utility as a predictor of failure. Materials and Methods. Fifty elbows with primary Coonrad-Morrey total elbow replacement were included. The quality of cementing was assessed by novel methods, the vertical and horizontal cementation index, which were statistically evaluated as predictors of failure. The mean period of followup was years (range: from 5.08 to 10.25 years). Results. The mean vertical cementation index of the humerus (vCIH) was 1.22 ± 0.28 and that of the ulna (vCIU) was . Radiolucent zones were noted in two cases in the humerus with a horizontal cementation index of 0.21 and 0.14, respectively. Both of the cementation indices were not found to be statistically significant predictors of failure ( ). The five-year survival rate was 94%. Discussion and Conclusion. The cementation index, being a ratio, reduces the confounding effect of taking radiographs in different positions of the limb with different magnification in followup radiographs. It is an easy and objective method of assessment of cementation, the results of which need to be validated by a larger study. 1. Introduction Total elbow replacement is used in the reconstruction of elbows afflicted by rheumatoid arthritis, osteoarthritis, and trauma. There has been a significant improvement in outcome with changes in the implant design, from the initial linked and fully constrained prostheses to the present-day unlinked and linked, semiconstrained implants. Linked prostheses, like the Coonrad-Morrey implant, have been reported to have better long-term functional outcomes than unlinked implants, like the Souter-Strathclyde prosthesis [1, 2]. Aseptic loosening is one of the most common causes of failure of the prosthesis in the long term [3, 4]. Inadequate cementing has been established to contribute to this complication [5, 6]. The aim of this study is to objectively evaluate cementation by a novel method called the cementation index and assess its utility as a predictor of failure. 2. Materials and Methods Fifty elbows (forty-seven patients), wherein primary total elbow replacement was performed, were included in the study. The Coonrad-Morrey type III prosthesis was used in all cases. The mean age of the patients was sixty-seven years (range from thirty-two to eighty-eight years). The male: female ratio was 20？:？30 elbows. The procedure was performed on the dominant limb in thirty-five elbows and on the right-hand side in thirty-one elbows.