Hip precautions following total hip arthroplasty (THA) limits flexion, adduction and internal rotation, yet these precautions cause unnecessary psychological stress. This study aims to assess bony and implant impingement using virtual models from actual patient's bony morphology and spinopelvic parameters to deduce whether hip precautions are necessary with precise implant positioning in the Asian population. Individualized sitting and standing sacral slope data of robotic THAs performed at two tertiary referral centers in Hong Kong was inputted into the simulation system based on patients’ pre-operative sitting and standing lumbar spine X-rays. Three-dimensional dynamic models were reconstructed using the Stryker Mako THA 4.0 software to assess bony and implant impingement both anteriorly and posteriorly, with default cup placement at 40° inclination and 20° anteversion. Femoral anteversion followed individual patient's native version. A 36mm hip ball was chosen for all cups equal or above 48mm and 32mm for those below. Anterior impingement was assessed by hip flexion and posterior impingement was assessed by hip extension. 113 patients were included. At neutral rotation and adduction, no patients had anterior implant impingement at hip flexion of 100°. 1.7% had impingement at 110°, 3.5% had impingement at 120°, 9.7% had impingement at 130°. With 20° of internal rotation and adduction, 0.8% had anterior implant impingement at hip flexion of 90°, 7.1% had impingement at 100° and 18.5% had impingement at 110°. With the hip externally rotated by 20°, 0.8% of patients had posterior implant impingement, and 8.8% bony impingement at 0° extension. With enabling technology allowing accurate component positioning, hip precautions without limiting forward flexion in neutral position is safe given precise implant positioning and adequate osteophyte removal. Patients should only be cautioned about combined internal rotation, adduction with flexion.
Local treatment with gentamicin may be an important tool in the prevention and treatment of surgical site infections in high-risk procedures and patients. The aim of this study was to evaluate the pharmacokinetic profile of gentamicin in bone and surrounding tissue, released from a controlled application of a GentaColl sponge in a porcine model. In 8 female pigs, a GentaColl sponge of 10×10 cm (1.3 mg gentamicin/cm2) was placed in a cancellous bone cavity in the proximal tibia. Microdialysis was used for sampling of gentamicin concentrations over 48 hours from the cavity with the implanted GentaColl sponge, cancellous bone parallel to the cavity over and under the epiphyseal plate, cortical bone, the intramedullary canal, subcutaneous tissue, and the joint cavity of the knee. Venous blood samples were obtained as reference.Aim
Method
With increased shift working, multiple hand-overs, demand for trauma beds frequently outstripping supply, split-site working, shared care with other specialties and tertiary referrals awaiting transfer, keeping track of trauma patients can be difficult. To solve this problem we developed the Virtual Trauma Orthopaedic Management System (VTOMS) to monitor pre-operative trauma inpatients. VTOMS is a secure, networked system linked to the patient administration system (PAS). It can be accessed by the entire multidisciplinary team from any PC in the Trust. The main information is also displayed on plasma screens in the trauma unit. The status of patients requiring surgery is displayed (e.g. fit and ready, awaiting investigation, or unfit) with alerts on acutely unwell or unstable patients. Further details can be obtained by ‘drilling down’. The system has an inbuilt patient clock which ‘traffic lights’ patients awaiting theatre, providing a visual warning if waiting time is prolonged. Amber is set at 48 hours and red is 72 hours for most injuries. This facilitates real-time management of the trauma workload, allowing extra resources to be deployed early if it is seen that waiting times are climbing, or the case-mix is particularly complex. After successful use on trauma inpatients, the VTOMS system was extended to create a ‘virtual trauma ward’ where patients are pre-assessed in hospital and, if clinically appropriate, wait at home until a suitable theatre slot becomes available. The patient is contacted daily to monitor their clinical situation and brought in fasting on the morning of surgery. Using this ‘just in time’ philosophy 195 patients passed through our ‘virtual trauma ward’ in the six months to December 2009. The reduced length of stay saved 514 bed days, equivalent to £115,650 (£231,300 per annum), and minimised the impact of trauma on the elective service.
