Introduction and Objective. Total knee arthroplasty (TKA) is a frequently and increasingly performed surgery in the treatment of disabling knee osteoarthritis. The rising number of procedures and related revisions pose an increasing economic burden on health care systems. In an attempt to lower the revision rate due to component malalignment and soft tissue imbalance in TKA, robotic assistance (RA) has been introduced in the operating theatre. The primary objective of this study is to provide the results of a theoretical, preliminary cost-effectiveness analysis of RA TKA. Materials and Methods. A Markov state-transition model was designed to model the health status of sixty-seven-year-old patients in need of TKA due to primary osteoarthritis over a twenty-year period following their knee joint replacement. Transitional probabilities and independent variables were extracted from existing literature. Patients’ state in the transition model was able to change on an annual basis. The main differences between the conventional and RA TKA were the outlier rate in the coronal plane and the cost of the procedure. In RA TKA, it was hypothesized that there were lower revision rates due to a lower outlier rate compared to conventional TKA. Results. The value attributed to the utility both for primary and revision surgery has the biggest impact on the ICER, followed by the rate of successful primary surgery and the cost of RA-technology. Only 2.18–2.34% of the samples yielded from the probabilistic sensitivity analysis proved to be cost-effective (threshold set at $50000/QALY). A calculated surgical volume of at least 191–253 cases per robot per year is needed to prove cost-effective taking the predetermined parameter values into account. Conclusions. Robot-assisted TKA might be a cost-effective procedure compared to conventional TKA if a minimum of 191 cases are performed on a yearly basis, depending on the cost of the robot. The cost-benefit of the robotic TKA surgery is mainly based on a decreased revision rate. This study is based on the assumption that alignment is a predictor of success in total knee arthroplasty. Until there is data confirming the assertion that alignment predicts success robot-assisted surgery cannot be recommended

Summary. Alignment results did not differ between PSG and conventional instrumentation. A small reduction in operation time and blood loss was found with the PSG system, but is unlikely of clinical significance. Length of hospital stay was identical for both groups. Introduction. Several techniques for aligning a TKA exist nowadays. Patient-specific guiding (PSG) has relatively recently been introduced to try to resolve the shortcomings of existing techniques while optimising the operative procedure. Still few reports have been published on the clinical outcome and on the peroperative results of this new technique. This prospective, double-blind, randomised controlled trial was designed to address the following research questions: 1. Is there a significant difference in outliers in alignment in the frontal and sagittal plane between PSG TKA and conventional TKA. 2. Is there a significant difference in operation time, blood loss and length of hospital stay between the 2 techniques. Patients & Methods. 180 patients were randomised for PSG TKA (group 1) or conventional TKA (group 2) in 2 centres. Patients were stratified per hospital. Alignment of the mechanical axis of the leg and flexion/extension and varus/valgus of the individual prosthesis components were measured on digital, standing, long-leg and standard lateral radiographs by 2 independent outcome assessors in both centres. Percentages of outliers, > 3°, were determined. We compared blood loss, operation time and length of hospital stay. Results. There was no statistically significant difference in mean mechanical axis or outliers in mechanical axis between groups. No statistically significant difference was found for the alignment of the individual components in the frontal plane, nor for the percentages of outliers. There was a statistically significant difference in outliers for the femoral component in the sagittal plane, with a higher percentage of outliers in the group 1 (p = 0.017). No such significant result was found for the tibial component in that plane. All interclass correlation coefficients were good. Blood loss was 100 mL less in group 1 (p = 0.000). Operation time was 5 minutes shorter in group 1 (p = 0.000). Length of hospital stay was almost identical with a mean of 3.6 days (p = 0.657). Discussion/Conclusions. The results in terms of obtaining a neutral mechanical axis and a correct position of the prosthesis components did not differ between groups. A small reduction in operation time and blood loss was found with the PSG system, but is unlikely of any clinical significance. Future research should especially focus on cost-effectiveness analysis and functional outcome of PSG TKA

This protocol describes a pragmatic multicentre randomised controlled trial (RCT) to assess the clinical and cost effectiveness of arthroscopic and open surgery in the management of rotator cuff tears. This trial began in 2007 and was modified in 2010, with the removal of a non-operative arm due to high rates of early crossover to surgery.

Cite this article: Bone Joint Res 2014;3:155–60.