The use of handheld cement sample as a guide to the setting of in situ cement mantle

During cemented joint arthroplasties, it is necessary to monitor the hardening of the cement to know when it is soft enough to allow insertion of the prosthesis but viscous enough to maintain bone interlock. Most often, a small piece of cement is left out and checked for hardening. These cement pieces are exposed to different fates, which include being held in the hand, held between fingers and kneaded, and left on the instrument table. The value of any of these techniques for predicting the cement's hardening has not been investigated formally. During 9 total hip arthroplasties, polymethyl methacrylate bone-cement was used in cementing the femoral component. Three 1-cm(3) samples collected from each operation site were exposed to the aforementioned 3 different conditions. The fingertip-held and kneaded cement specimens most closely predicted the time to setting of the cement mantle at the operation site.