We conducted a meta-analysis, including randomised controlled trials (RCTs) and cohort studies, to examine the effect of patient-specific instruments (PSI) on radiological outcomes after total knee replacement (TKR) including: mechanical axis alignment and malalignment of the femoral and tibial components in the coronal, sagittal and axial planes, at a threshold of > 3º from neutral. Relative risks (RR) for malalignment were determined for all studies and for RCTs and cohort studies separately. Of 325 studies initially identified, 16 met the eligibility criteria, including eight RCTs and eight cohort studies. There was no significant difference in the likelihood of mechanical axis malalignment with PSI versus conventional TKR across all studies (RR = 0.84, p = 0.304), in the RCTs (RR = 1.14, p = 0.445) or in the cohort studies (RR = 0.70, p = 0.289). The results for the alignment of the tibial component were significantly worse using PSI TKR than conventional TKR in the coronal and sagittal planes (RR = 1.75, p = 0.028; and RR = 1.34, p = 0.019, respectively, on pooled analysis). PSI TKR showed a significant advantage over conventional TKR for alignment of the femoral component in the coronal plane (RR = 0.65, p = 0.028 on pooled analysis), but not in the sagittal plane (RR = 1.12, p = 0.437). Axial alignment of the tibial (p = 0.460) and femoral components (p = 0.127) was not significantly different. We conclude that PSI does not improve the accuracy of alignment of the components in TKR compared with conventional instrumentation. Cite this article: Bone Joint J 2014; 96-B:1052–61.

Introduction: Although prophylactic tranexamic acid (TXA) is a safe, low-cost option to reduce bleeding in patients undergoing total hip replacement (THR), its optimal dose and duration is unknown. We compared the safety and effectiveness of TXA given as either a single injection or continuous infusion in THR patients, hypothesising that a second TXA dose would not offer any clinical advantages over the single injection. Materials and methods: One hundred and sixty-four patients undergoing unilateral THR were randomised. Exclusion criteria were history of thromboembolic events (TE), epilepsy, thrombophilia, and severe chronic renal failure. Patients received either a single dose of 30 mg/kg TXA on induction of surgery (one shot [OS] group), or a loading dose of 10 mg/kg TXA followed two hours later by a continuous infusion of 2 mg/kg per hour for 20 hours (one day [OD] group). The primary outcome was blood loss (BL) calculated from haematocrit levels. Secondary outcomes were mortality and TE events within 90 days postoperatively. Results: All patients completed treatment, with none lost to follow-up. Mean BL was 1107 ± 508 ml in Group OS and 1047 ± 442 ml in Group OD (p = 0.43). No patients were transfused prior to Day 10 postoperatively. At final follow-up, no patients had died, and there were no occurrences of major TE. Conclusion: The 30 mg/kg TXA single shot was as safe as continuous infusion. As it is also less cumbersome, we recommend it as part of routine care in THR patients.