Charles A Willis-Owen

Factors affecting the incidence of infection in hip and knee replacement: AN ANALYSIS OF 5277 CASES

Infection remains a significant and common complication after joint replacement and there is debate about which contributing factors are important. Few studies have investigated the effect of the operating time on infection. We collected data prospectively from 5277 hip and knee replacements which included the type of procedure, the operating time, the use of drains, the operating theatre, surgeon, age and gender. In a subgroup of 3449 knee replacements further analysis was carried out using the tourniquet time in place of the operating time. These variables were assessed by the use of generalised linear modelling against superficial, deep or joint-space post-operative infection as defined by the Australian Surgical-Site Infection criteria. The overall infection rate was 0.98%. In the replacement data set both male gender (z = 3.097, p = 0.00195) and prolonged operating time (z = 4.325, p < 0.001) were predictive of infection. In the knee subgroup male gender (z = 2.250, p = 0.02447), a longer tourniquet time (z = 2.867, p = 0.00414) and total knee replacement (versus unicompartmental knee replacement) (z = -2.052, p = 0.0420) were predictive of infection. These findings support the view that a prolonged operating time and male gender are associated with an increased incidence of infection. Steps to minimise intra-operative delay should be instigated, and care should be exercised when introducing measures which prolong the duration of joint replacement.

Unicondylar knee arthroplasty in the UK National Health Service: An analysis of candidacy, outcome and cost efficacy

The viability of unicondylar knee arthroplasty (UKA) as a stand-alone or temporising option for the management of gonarthrosis is a topic of considerable contention. Despite recent advances in prosthesis design and surgical technique, as well as mounting evidence of long-term survivorship, UKA remains infrequently used, accounting for just 8-15% of all knee arthroplasties. Instead this group is more typically managed using total knee arthroplasty (TKA). For UKA to warrant increased usage the candidacy for UKA must be prevalent, the outcome must be equivalent or superior to that of TKA, and the costs should be comparatively low. Here we address three issues regarding UKA: 1) a prospective assessment of the proportion of knees needing arthroplasty that are candidates for UKA; 2) retrospective outcome measures comparing TKA, UKA and controls; and 3) an estimation of the difference in costs between TKA and UKA from a hospital perspective. We show in a series of 200 knees that candidacy for UKA is widespread; representing 47.6% of knees. Furthermore, we also show for the first time, that not only is UKA functionally superior to TKA (based on Total Knee Questionnaire (TKQ) scores), but scores in medial and lateral UKA knees do not differ significantly from normal, non-operative age- and sex-matched knees (t=1.14 [38], p=0.163; and t=1.16 [38], p=0.255 respectively). Finally, we report that UKA offers a substantial cost saving over TKA ( pound 1761 per knee) indicating that UKA should be considered the primary treatment option for unicompartmental knee arthritis.

Bilateral femoral neck fractures due to transient osteoporosis of pregnancy: a case report

We describe a case of bilateral femoral neck fractures secondary to transient osteoporosis of pregnancy, which were diagnosed after delivery due to the desire to avoid ionising radiation. These fractures were presumed to be secondary to transient osteoporosis of pregnancy and were treated successfully with internal fixation despite delayed presentation. We discuss the role of MRI in the evaluation of hip pain in pregnancy.

Bilateral ganglion cysts of the cruciate ligaments: a case report

Symptomatic ganglion cysts of the cruciate ligaments are rare, and bilateral cases are extremely rare, with only one reported case in the literature. We report a case of bilateral cruciate ligament ganglion cysts successfully treated with arthroscopic resection, and review the literature regarding aetiology, diagnosis and management.

Failure of asnis iii 5.0 mm cannulated screw: a case report

We describe a case of an ASNIS III 5.0 mm partially threaded cannulated screw unthreading itself as it was being inserted during fracture fixation of a humerus. The majority of complications associated with cannulated screws involve breaking of the screw, as opposed to unthreading. We believe that the self tapping design of the screw, in combination with the cannulated design, creates a potential area of weakness when used on hard bone.

Innovation in surgery.

The comprehensive and enlightening editorial by Professor Campbell left me with a number of questions. As a keen innovator, I had not given much thought to the risks of litigation. The summary of the relevant regulatory advice was clear, comprehensive and useful. Nevertheless, the MDA/MHRA regulations are subject to interpretation and appear vague and unhelpful. For example, does blunt dissection with scissors constitute ‘off label’ use as they are designed for cutting? Is it no longer acceptable to use a DCS implant to fix a subtrochanteric femoral fracture in the light of much more expensive intramedullary nails marketed for this fracture pattern? The list of example is endless, and ranges from what many would consider to be standard practice, to what some may consider to be quite out of the ordinary. The notion that commercially available alternatives must be used if they exist has enormous cost implications; indeed, I am sure a fortune could be made converting many of the innovations seen in the ‘Technical Tips’ section of the Annals into purpose-made devices. I feel this matter should prompt debate, and perhaps we can produce somewhat clearer standards before one poor surgeon is quoted these vague MDA/MHRA regulations in court.