Abstract
Introduction and aim: prosthesis displacement while attempting closed reduction of a dislocated total hip or during dislocation itself is a rare but significant complication. We have come across three cases and there are at least six case reports in the literature. The aim of our study is to conduct an in vitro biomechanical study to assess, whether application of bone cement over the shoulder of the stem confers any additional advantage in the pull out strength of the implant.
Materials and Methods: We used fourteen saw bones and cemented seven bones with a standard cementing technique and another seven bones with additional cement over the shoulder of the implant. A tensile testing machine was used to assess the pull out force needed in both groups. A comparision was done between both groups.
Results: The mean pull out force in the routine cementing technique was 2066N(S.D. 256.65) and for the group with the cement on the shoulder was 3220N(S.D. 312.22). The mean difference was 1154N. The results were analysed with two-tailed t- test, unequal variance and the difference was statistically significant with p value of 0.00045.
Conclusion: Our experiment confirms that application of the bone cement over the shoulder of the implant does give additional axial stability and should be practised routinely to reduce this complication.
Correspondence should be addressed to The Secretary, BHS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
