RESUMO
Introduction Leg length and offset are important considerations in total hip arthroplasty (THA). Navigation systems are capable of providing intra-operative measurements of leg length and offset, and high accuracy has been shown in experimental studies. This study assesses the accuracy of an imageless navigation system with a pinless femoral array (Hip 5.1, BrainLAB, Feldkirchen, Germany) in measuring leg length and offset changes in vivo. Methods A prospective, consecutive series of 37 patients undergoing navigated THA were included in the study. Intra-operative measurements of leg length and offset were recorded using the navigation system. For each patient, pre- and post-operative digital radiographs were scaled and analyzed to provide radiographic measurements for comparison. Results Measurements of leg length change made by the navigation system showed a strong correlation with the size of change measured radiographically (R = 0.71; p<0.0001). The mean difference between the radiographic and navigational measurement was 2.6mm ± 3.0mm (0.0-16.0mm) (mean, SD, range). The navigation system was accurate to within 1mm of the radiographic measurement in 49% of cases, within 2mm in 66% of cases, and within 5mm in 89% of cases. Measurements of offset change by the navigation system also showed a correlation with radiographic measurements, albeit less pronounced (R = 0.35; p=0.035). The mean difference between navigational and radiographic measurements was 5.5mm ± 4.7mm (0.0-16.0mm) (mean, SD, range). The navigation system was accurate within 1mm of the radiographic measurement in 22% of cases, within 2mm in 35% of cases, and within 5mm in 57% of cases. Conclusions This research demonstrates in vivo that an imageless, non-invasive navigation system is a reliable tool for intra-operative leg length (accurate within 2mm) and to a lesser extent offset measurement (accurate within 5mm) when compared to standard practice of plain film radiographs.
RESUMO
Introduction In Western Australia, vast distances between hospitals can limit a patient's access to timely surgical intervention. The aim was to examine the effect of patient location on outcomes. Methods Hip fracture data from all operative cases at the major Western Australian hospitals between 2015 and 2019 was retrospectively reviewed. A total of 5691 patients were separated into three groups based on hospital of first presentation - directly to the operative hospital (metropolitan), a hospital less than 2.5 hours by road from the operative centre (outer-metropolitan), or requiring transfer by air (rural). Impact of location on time to surgery, length of stay and 30-day and 120-day mortality was analysed. Results The mean time to surgery was 26.7 hours for metropolitan patients, 37.0 hours for outer-metropolitan, and 42.6 hours for rural patients. Outer-metropolitan patients were less likely to reach surgery within 48 hours than metropolitan patients (80.2% vs 91.5%, p<0.001), with even lower rates for rural patients (66.8%, p<0.001). Acute length of stay was longer for rural patients compared to outer-metropolitan (7.2 vs 5.8 days) and metropolitan patients (5.5 days) (p<0.001). There was no significant difference in 30-day or 120-day mortality for outer-metropolitan or rural patients compared to metropolitan patients despite requiring transfer. However, when considered as a whole group there was an increased 120-day mortality with increased time to surgery. Overall mortality was 8.7% at 30 days and 17.3% at 120 days. Conclusion Patients presenting outside the metropolitan area with a hip fracture have a longer time to surgery and longer length of stay. Delay for outer-metropolitan patients is disproportionately longer than transit time alone and may provide opportunities for improvement.