Orthopaedic simulators are popular in innovative surgical training programs, where trainees gain procedural experience in a safe and controlled environment. Recent studies suggest that an ideal simulator should combine haptic, visual, and audio technology to create an immersive training environment. This article explores the potentialities of mixed-reality using the HoloLens to develop a hybrid training system for orthopaedic open surgery. Hip arthroplasty, one of the most common orthopaedic procedures, was chosen as a benchmark to evaluate the proposed system. Patient-specific anatomical 3D models were extracted from a patient computed tomography to implement the virtual content and to fabricate the physical components of the simulator. Rapid prototyping was used to create synthetic bones. The Vuforia SDK was utilized to register virtual and physical contents. The Unity3D game engine was employed to develop the software allowing interactions with the virtual content using head movements, gestures, and voice commands. Quantitative tests were performed to estimate the accuracy of the system by evaluating the perceived position of augmented reality targets. Mean and maximum errors matched the requirements of the target application. Qualitative tests were carried out to evaluate workload and usability of the HoloLens for our orthopaedic simulator, considering visual and audio perception and interaction and ergonomics issues. The perceived overall workload was low, and the self-assessed performance was considered satisfactory. Visual and audio perception and gesture and voice interactions obtained a positive feedback. Postural discomfort and visual fatigue obtained a nonnegative evaluation for a simulation session of 40 minutes. These results encourage using mixed-reality to implement a hybrid simulator for orthopaedic open surgery. An optimal design of the simulation tasks and equipment setup is required to minimize the user discomfort. Future works will include Face Validity, Content Validity, and Construct Validity to complete the assessment of the hip arthroplasty simulator.

Purpose The aim of this study was to review patients that underwent ACL reconstruction with the LARS™ ligament in the First Orthopaedic Division of Pisa University during the period between January 2003 and December 2005. Methods Twenty-six patients were reviewed with an average follow-up of 95.3 months (7.9 years). The review protocol was articulated in three phases: (1) a subjective evaluation using three grading scales: VAS, KOOS and the Cincinnati knee rating scale, (2) a clinical and objective evaluation, and (3) a biomechanical evaluation of the knee stability. Results A global positive result was obtained in 92.3 % of the patients (16 optimal results and eight good results), with a fast functional recovery and a high knee stability. A global poor result was reported in two cases. In our series we did not record cases of infection or knee synovitis. We recorded only one case of mechanical graft failure. The results obtained from our study are encouraging and similar to those in the literature. Conclusions We conclude that the LARS™ ligament can be considered a suitable option for ACL reconstruction in carefully selected cases, especially for older patients needing a fast functional recovery.

Acromio-clavicular joint (ACJ) injuries represent nearly half of all athletic shoulder injuries. Stability of this joint depends on the integrity of the acromio-clavicular and coracoclavicular ligaments. Although the traumatic acromioclavicular joint separation is a well-known topic, there are different classifications, diagnostic procedures, concepts of intervention, and a great variety of implants. In this paper, we present an overview of the recent literature about this issue and the results of a retrospective non-randomized study with 2 different techniques. At the first Orthopedic Department of University of Pisa, a retrospective study was performed starting from January 2007 to February 2011 in our electronic database. We selected patient treated with two different techniques (tight-rope(®) system and hook plate) by the same senior surgeon with experience in shoulder surgery. The mean Costant score was 90 for the tight-rope(®) system group and 75 for the hook plate group. At the final follow-up, most of the patients had returned to their preinjury level of activity. Two patients had a breakage of the fixating system. The above-mentioned techniques provided satisfactory results with no loss of reduction except in two cases. The use of the hook plate is useful in fracture-dislocation of ACJ, but this requires another surgery to remove it. On the contrary, the use of the tight-rope(®) system does not require a new surgery or use of expensive synthetic graft or a graft harvested from a distant donor site.

No abstract