Pull-out strength of a polished tapered stem is improved by placing bone cement over the shoulder of the implant

Displacement of a polished stem while attempting closed reduction of a dislocated total hip or during dislocation itself is a rare but significant complication. Our aim was to assess whether applying bone cement over the shoulder of the implant can help to prevent this. We conducted an in vitro mechanical study with tensile testing machine. We cemented 7 sawbones with a standard cementing technique and another 7 with additional cement over the shoulder of the implant. The mean pull-out force in the routine cementing technique was 2066 N (SD, 256.65), and it was 3220 N (SD, 312.22) for the group with the cement on the shoulder. There is a statistically significant difference of 1154 N. We recommend that when a polished stem is used, bone cement should be applied over the shoulder of the implant.