Back to the Future? Institutional Learning Curves and Intraoperative Fracture Rates Associated With Adoption of a Cemented Composite Beam Stem for Hemiarthroplasty

Background Hemiarthroplasty remains the gold standard for hip fracture care in displaced intracapsular fractures. There is now substantial evidence that uncemented femoral stems are associated with higher risk of perioperative fractures. Cemented composite beam (CCB) stems offer some of the lowest overall rates of perioperative fracture risk, but are not widely used in the Irish system, and concern regarding the use of new implants and associated learning curves can act as a barrier to change. Objectives We aim to assess our units experience transitioning to a cemented composite beam (CCB) and the associated learning curve and technical pitfalls. Design Retrospective, single centre, single blind review identified the first 140 cases of CCB stems. Methods Post-operative radiographs on all cases were assessed for perioperative fracture and stems were classed as being varus or valgus if the stem alignment was >3 degrees from the anatomical axis. A cemented taper slip (CTS) stem, which was in use for over 10 years in the unit, provided a control group. Results Following introduction, higher odds of malalignment were experienced with the CCB stem (OR 2.19, 1.09-4.55 p<0.031), relative to CTS. However, compared to overall rate of malalignment in the CTS group (9.3%), the learning curve for the CCB stem was short, with rates of malalignment returning to in line with our control CTS cohort within 46 cases (Cases 1-46 32% malaligned, cases 47-92 10.86% malaligned, cases 93-138 4.34% malaligned). There was no increased risk of periprosthetic fracture demonstrated with introduction of the new stem. Conclusions We have shown a relatively short learning curve associated with transitioning to a CCB stem for fragility fracture hemiarthroplasty. We highlight some of the early technical issues experienced and corrected.