1 Optimal queue length for orthopaedic surgery with surgeon-specific queues and maximum waiting time Antti Peltokorpi 1 , Juha-Matti Lehtonen 2 , Paulus Torkki 1 , Teemu Moilanen 3 1 Helsinki University of Technology, Institute of Healthcare Engineering, Management and Architecture, Espoo (Finland), antti.peltokorpi@tkk.fi , paulus.torkki@tkk.fi 2 Tampere University of Technology, Department of Industrial Management, Tampere (Finland), juha-matti.2.lehtonen@tut.fi 3 Coxa Ltd, Hospital for Joint Replacement, Tampere (Finland), teemu.moilanen@coxa.fi Abstract: Lengthened waiting times to surgical operations lead to a diminished patient satisfaction, deteriorated medical quality and increased costs. In order to avoid long queues, authorities have enacted care guarantees that define the maximum waiting time to services. In this study, the effect of queue length and care guarantee of maximum waiting time on OR productivity is discussed from a case perspective of an orthopaedic surgery hospital. With 6 months care guarantee the optimal average queue length was 3 months. This is only few weeks longer than patient preferences. With shorter queues there existed problems in finding appropriate cases to fulfill the OR session. With longer queues cases exceeding the care guarantee disturbed the optimal scheduling. The study indicates that the introduction of care guarantee might deteriorate the overall efficiency and increase the average waiting time. More sophisticated scheduling algorithms are needed to maintain efficiency with care guarantees. 1 Introduction Lengthened waiting times tend to be a problem in many public-funded health care systems. For example in surgical operations long waiting times lead to a diminished patient satisfaction, deteriorated medical quality and increased care costs (Kujala et al. 2006). Most of those disadvantages burden primarily patients and her family and employer. Service provider might even benefit from long waiting times if there is no real competition or financing is budget-based and not fee for service. In order to avoid long queues, authorities in countries with public-funded system have implemented several policies to cut waiting times. Enacting care guarantee that defines the maximum waiting time to services is one of the used policies (Hanning 1995). However, the effect of those policies on the production efficiency is weakly understood. From a service provider perspective, some queues for surgery are needed to maximize the use of fixed operating room (OR) capacity. Based on basics of queuing theory, there exists always a trade-off between short waiting times and high utilization rates. Optimization of OR efficiency becomes more problematic when surgeons have own patients and queues. In this study, the effect of queue length and care guarantee of maximum waiting time on OR productivity was analyzed and discussed. 2 Managing waiting times Deteriorating effects of waiting times have been considered in several studies. Coyte et al. (1994) argued that from a patient perspective, optimal waiting time to elective surgery is between three to eight weeks. Oudhoff et al. (2007) expanded the acceptable range between 2 and 25 weeks depending on the type of disorder and the severity of physical and psychosocial problems of patients. Anyway, those time frames are nowadays exceeded in many public-funded hospitals. Long waiting time affects negatively on patient’s quality of life and recovery process (e.g.