# Smart Product Design Process through the Implementation of a Fuzzy Kano-AHP-DEMATEL-QFD Approach
## 4 Case Study: A Hip Replacement Surgery Aid Device for Elderly People  
The only available alternative for people with the hip joint condition is Total Hip Replacement (THR) (Figure 1). THR consists of a surgical procedure that reconstructs the hip joint. In particular, the acetabulum is substituted by a cup fixed to the basin, while the femur head is removed and replaced by a spherical head and a stem fixed in the femur. In this case, the focus of the study was SAD, which allows the physician to properly position the hip implant. This includes alignment, suggestions related to the cutting points, the size of acetabular coupling, and other relevant information for the successful positioning of the hip implant. In this process, physicians are considered as the final customers, considering that they have collected the fears and concerns of the patients and also are aware of the need to have a good product at a price it can be affordable for the majority of the people. The company produces installation aid kits that can be used with different prosthesis manufacturers. The company wishes to improve the current installation aid kit, considering the feedback given by physicians and prosthesis manufacturers. The installation aid kit consists of a measuring and aligning device that is disposable and fixation elements for the measuring devices and femur head cut. These fixation elements are not disposable. The components of the installation kit were analyzed by a design team of the company, considering the feedback of the customers, letting the team define the following customer needs for the kit:  
_R-Reliability:_ It refers to the fact that the device should be in good condition at the moment of use. That means, it has enough batteries; it is complete, calibrated, and in good condition. _UF-User friendly (easy to use):_ This refers to the fact that the device should have less auxiliary pieces as possible, they are correctly marked, and has an error-proved design (only can be assembled correctly). _FI-Friendly interface (friendly user-software interface):_ Relates with the fact that the physician can interact easily with the application, in terms that can find the data fast, and the answer of the application is clear for the physician. _LI-Low invasion (less invasive possible):_ This refers to the fact that the installation should preferably not require a bigger surgical incision, or additional exposure of the bones or flesh, to reduce the risk of infections or trauma. _QI-Quick installation (place device into an operating area):_ This issue is related to the fact that the installation and use of the device require fewer operations and equipment as possible, so the device parts can be assembled and disassemble quickly and safely so that the physician can focus on the surgical procedure. SS-Software stabilityThis refers to the fact that the software should make the calculations properly without mistakes and should have some warning alerts to prevent mistakes by the physician. CI-Collateral issues (low bone wearing)The installation of the device should not weaken the areas where it will be installed. This means no excess drilling (number of holes and size of holes). In case screws are used to fix the tool to the bone, screws should measure ten millimeters or less. A-Accuracy (quality of measures)This refers to the fact that the software should provide the proper measure related to the length and offset so that the physician can use the data to make decisions related to the head and neck to be used. C-CommunicationCommunication between sensors and devices should be stable. This means the communication between the iPad and the device must be stable, and, in case there is a sudden interruption, data should be recovered by the system without affecting the related results. This communication must not be affected by cellular electromagnetism of the devices in the area, mobile phones, or any other electronic device in the operating room.