Retrospective cohort study of the performance of the Pinnacle metal on metal (MoM) total hip replacement: a single-centre investigation in combination with the findings of a national retrieval centre.

OBJECTIVES: To determine risk factors for revision in patients implanted with a commonly used metal on metal (MoM) hip replacement. DESIGN: Retrospective cohort study in combination with a prospective national retrieval study (Northern Retrieval Registry (NRR)). SETTING: Combined orthopaedic unit in combination with the NRR. PARTICIPANTS: All patients implanted with a DePuy Pinnacle MoM hip prostheses by the 2 senior authors were invited to attend for a review which included clinical examination, blood metal ion measurements, radiographs and targeted imaging. Explanted components underwent wear analysis using validated methodology and these results were compared with those obtained from the NRR. RESULTS: 489 MoM Pinnacle hips were implanted into 434 patients (243 females and 191 males). Of these, 352 patients attended the MoM recall clinics. 64 patients had died during the study period. For the purposes of survival analysis, non-attendees were assumed to have well-functioning prostheses. The mean follow-up of the cohort as a whole was 89 months. 71 hips were revised. Prosthetic survival for the whole cohort was 83.6% (79.9-87.3) at 9 years. The majority of explanted devices exhibited signs of taper junction failure. Risk factors for revision were bilateral MoM prostheses, smaller Pinnacle liners, and implantation in 2006 and later years. A significant number of devices were found to be manufactured out of their specifications. This was confirmed with analysis of the wider data set from the NRR. CONCLUSIONS: This device was found to have an unacceptably high revision rate. Bilateral prostheses, those implanted into female patients and devices implanted in later years were found to be at greater risk. A significant number of explanted components were found to be manufactured with bearing diameters outside of the manufacturer's stated tolerances. Our findings highlight the clinical importance of hitherto unrecognised variations in device production.

Topical (intra-articular) tranexamic acid reduces blood loss and transfusion rates following total knee replacement: a randomized controlled trial (TRANX-K).

BACKGROUND: Approximately one-third of patients undergoing total knee replacement require one to three units of blood postoperatively. Tranexamic acid (TXA) is a synthetic antifibrinolytic agent that has been successfully used intravenously to stop bleeding after total knee replacement. A topical application is easy to administer, provides a maximum concentration of tranexamic acid at the bleeding site, and is associated with little or no systemic absorption of the tranexamic acid. METHODS: A double-blind, randomized controlled trial of 157 patients undergoing unilateral primary cemented total knee replacement investigated the effect of topical (intra-articular) application of tranexamic acid on blood loss. The primary outcome was the blood transfusion rate. Secondary outcomes included the drain blood loss, hemoglobin concentration drop, generic quality of life (EuroQol), Oxford Knee Score, length of stay, a cost analysis, and complications as per the protocol definitions. RESULTS: Tranexamic acid reduced the absolute risk of blood transfusion by 15.4% (95% confidence interval [CI], 7.5% to 25.4%; p = 0.001), from 16.7% to 1.3%, and reduced blood loss by 168 mL (95% CI, 80 to 256 mL; p = 0.0003), the length of stay by 1.2 days (95% CI, 0.05 to 2.43 days; p = 0.041), and the cost per episode by £333 (95% CI, £37 to £630; p = 0.028). (In 2008, £1 = 1.6 U.S. dollars.) Oxford Knee Scores and EuroQol EQ-5D scores were similar at three months. CONCLUSIONS: Topically applied tranexamic acid was effective in reducing the need for blood transfusion following total knee replacement without important additional adverse effects. LEVEL OF EVIDENCE: Therapeutic level I. See Instructions for Authors for a complete description of levels of evidence.

Topical (intra-articular) tranexamic acid reduces blood loss and transfusion rates following total hip replacement: a randomized controlled trial (TRANX-H).

BACKGROUND: Approximately one-third of patients undergoing total hip replacement surgery require one to three units of blood postoperatively. Tranexamic acid is a synthetic antifibrinolytic agent that has been successfully used intravenously to control bleeding after total hip replacement. A topical application is easy to administer, provides a maximum concentration of tranexamic acid at the bleeding site, and is associated with little or no systemic absorption of the tranexamic acid. METHODS: A double-blind, randomized controlled trial of 161 patients undergoing unilateral primary total hip replacement investigated the effect of topical (intra-articular) application of tranexamic acid on blood loss. The primary outcome was the blood transfusion rate. Secondary outcomes included the drain blood loss, hemoglobin concentration drop, generic quality of life (EuroQol), Oxford Hip Score, length of stay, a cost analysis, and complications. RESULTS: Tranexamic acid reduced the absolute risk of blood transfusion by 19.6% (95% confidence interval [CI], 6.9% to 32.1%; p = 0.004), from 32.1% to 12.5%, and reduced blood loss by 129 mL (95% CI, 47 to 211 mL; p = 0.002), the hemoglobin concentration drop by 0.84 g/dL (95% CI, 0.41 to 1.27; p < 0.0001), the length of stay by 1.0 days (95% CI, -0.2 to 2.3 days; p = 0.109), and the cost per episode by £305 (95% CI, £0 to £610; p = 0.05). (In 2010, £1 = 1.5 U.S. dollars.) Oxford Hip Scores and EuroQol scores were similar at three months. CONCLUSIONS: Topically applied tranexamic acid was effective in reducing blood loss and the need for blood transfusion following total hip replacement, avoiding the potential complications of intravenous tranexamic acid administration. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.