Time at the surgical ‘coal-face’ has been reduced by introduction of the European Working Time Directive (EWTD) significantly impacting training opportunity. Our null hypothesis was that duration of surgery is significantly longer if a trainee were performing the operation despite supervision or level of trainee experience. Cemented hip hemiarthroplasty was chosen as our index procedure as complexity is largely comparable between cases. 461 patients were identified on the hospital trauma database. Data were augmented by information regarding level of surgeon, assistant and time of surgery from the hospital theatre database. There was no significant difference in registrar and consultant operative times, mean time 69 and 72 minutes respectively. SHOs were significantly slower (mean 80 minutes, p=0.0006). Junior (ST5 or less) registrars were significantly slower (mean 81minutes, p=0.0002) whereas senior registrars were not. Supervision level had no effect on duration of senior registrar operations but when junior registrars were consultant supervised they were not significantly slower (mean 75 minutes, p=0.09). Supervised operating therefore reduces time variability and should be promoted within a climate of training. Increase in mean operative time in registrars and SHOs is insignificant within a day's operating and is unlikely to lead to cancellations of cases.
Medical and Health care products Regulatory Agency (MHRA) released an alert in 2010 regarding metal on metal (MoM) bearings in hip arthroplasty owing to soft tissue reactions to Metal debris. Following this, we adopted a targeted screening protocol to review patients with this bearing couple. 218 Patients (252 hips), mean age 53.2 (25–71) years were assessed clinically using Oxford hip score (OHS) and X-ray examination. The mean follow up was 44.5 (12–71) months. Patients were considered at higher risk (118 patients/133 hips) if they had deterioration of OHS (50 hips), Small sized heads <50mm (114 hips), acetabular inclination >500 (37 hips), neck thinning (17 hips). These patients (107/118), (120/133 hips) were further investigated through measuring metal ion levels and magnetic resonance imaging (MRI). The mean blood levels of cobalt and chromium in this group were 6.7, 8.62 ug/L respectively. Metal ions increased significantly with high acetabular inclination angles (p=0.01, 0.004 respectively), but was not affected by the size of the head (p=0.13). MRI showed periprosthetic lesions around 28 hips (26 fluid collections, 2 pseudotumours). The screening protocol detected all patients who subsequently required elective revision. We believe that this protocol was beneficial in detecting problematic MoM hip replacements.
We investigated the role of Plasma Viscosity (PV), C-reactive protein (CRP) and Frozen Section (FS) in diagnosing prosthetic joint infection. We compared these results with microbiological diagnosis of infection of the tissue samples (three or more samples grown same organisms in culture). 53 patients, average age 67 years (37 – 89) underwent joint revision surgery. 34 patients had hip and 19 patients had knee joint revision arthroplasty, this includes single and multiple stage revision surgeries and excision arthroplasty. Nine (17%) patients had microbiologically proven joint infection. PV had sensitivity of 100%, specificity of 43% and negative predictive value of 100%. CRP had sensitivity of 89 %, specificity of 75% and negative predictive value of 97%. FS (presence of infection being more than 5 neutrophils/hpf) had sensitivity of 56% and specificity of 84%. We recommend PV and CRP to be used in the investigation of prosthetic joint infection. If both CRP and PV are normal the chance of infection is very low (negative predictive value of 100%). In our series an elevated PV and CRP represented a 50% chance of having a joint infection. The role of frozen section does not appear to be beneficial in the diagnosis of joint
