Jason Webb

Re-infection outcomes following one- and two-stage surgical revision of infected hip prosthesis in unselected patients: protocol for a systematic review and an individual participant data meta-analysis.

BackgroundSeveral aggregate published reviews have compared the effectiveness of one- and two-stage surgical revision to prevent re-infection following prosthetic hip infection and have reported inconsistent results. In addition, there were several features of these previous reviews which limited the validity of the findings. In the absence of a well-designed clinical trial, we propose the Global Infection Orthopaedic Management (INFORM) collaboration, a worldwide collaborative systematic review and meta-analysis of individual participant data (IPD) to address the existing uncertainties.MethodsCohort studies (prospective or retrospective) and randomised controlled trials conducted in unselected patients with infection treated exclusively by one- or two-stage revision and reporting re-infection outcomes within 2 years of revision will be retrieved by searching the following databases: MEDLINE, EMBASE, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials and the WHO International Clinical Trials Registry Platform. Reference lists of relevant studies will be manually scanned and there will be email contact with investigators of grey literature and conference abstracts. Investigators will be invited to join the Global INFORM collaboration and share their individual level data. The primary outcome of the analyses will be incidence of re-infection within 2 years of commencement of revision surgery. Primary analyses will be conducted comparing the one-stage to the two-stage surgical revision. IPD analyses will be based on Cox proportional hazard (PH) models estimated for each study separately. Study-specific log hazard ratios will be combined using random-effects meta-analysis with fixed-effects meta-analysis in subsidiary analyses. Hazard ratios for re-infection according to different individual level characteristics such as sex, age groups, body mass index and comorbidities will also be assessed.DiscussionThe analyses will enable a consistent approach to the definition of re-infection outcomes, more detailed analyses under a broader range of circumstances and exploration of potential sources of heterogeneity and produce much more valid and precise estimates of re-infection outcomes.Systematic review registrationPROSPERO 2015: CRD42015016664

One-stage exchange for prosthetic joint infection of the hip.

Exchange arthroplasty remains the gold standard of treatment of established prosthetic joint infection. This can be achieved using a one or two stage approach. The ENDO-Klinik, in Hamburg, has pioneered the one-stage technique since 1970 utilising antibiotic loaded acrylic cement (ALAC). This editorial discusses the relevant literature and describes the indications and surgical technique employed by the ENDO-Klinik Hamburg.

Stem compatibility for cement-in-cement femoral revision: an in vitro study

Cement-in-cement femoral component revision is a useful and commonly practised technique. Onerous and hazardous re-shaping of the original cement mantle is required if the new stem does not seat easily. Furthermore, without removing the entirety of the original cement mantle, the freedom to alter anteversion or leg length is difficult to predict preoperatively. We present data from in vitro experiments testing the compatibility of the top cemented stems according to UK registry figures (NJR 2013). This data augments preoperative planning by indicating which revision stems require minimal or no cement reshaping when being inserted into another stems mantle. We also present the maximum shortening and anteversion that can be achieved without reshaping the original cement mantle.

Comparison of three methods of antibiotic prophylaxis in knee arthroplasty

Prophylactic intravenous cefamandole nafate was administered by the systemic, systemic with probenecid (causing renal tubular blockade of antibiotic excretion), and intravenous regional routes. Bone antibiotic levels were assayed 15 minutes and 12 hours after administration, and hematoma concentrations after 8 hours. Bone concentrations after intravenous regional administration were significantly greater than systemic after 15 minutes, but were not detectable after 12 hours. Probenecid produced inhibitory concentrations in bone after 12 hours and also increased hematoma antibiotic concentrations to three times those achieved by systemic administration. Adequate prophylaxis may be possible with two rather than three doses of cefamandole if probenecid is used.

Acute calcific periarthiritis of the knee presenting with calcification within the lateral collateral ligament

A 71-year-old woman was admitted with acute swelling of the right knee, pain on the lateral aspect and restricted movement. There was no instability or locking. She had no history of trauma and was generally in good health. Plain radiographs demonstrated a calcific opacity adjacent to the lateral femoral condyle. This was shown to be within the lateral collateral ligament (LCL) at ultrasound and MRI. A diagnosis of acute calcific periarthritis (ACP) was made. The patients symptoms resolved within a few weeks with simple analgaesia. ACP presenting with calcification within the LCL is rare. It is important to recognise the clinical and imaging findings of this condition as it may mimic other more serious pathologies such as infection and gout. This may result in unnecessary investigations, misdiagnoses and incorrect treatments.