Patient-specific instrumentation for total shoulder arthroplasty

[摘要] Accurate glenoid component placement is of major importance in shoulder arthroplasty. Improperly-placed implants are at risk of dislocation, increased component wear and loosening, and the need for revision surgery.1-3 Avoiding glenoid component malposition in terms of version and inclination is therefore an important technical goal, which may be very demanding due to a variety of issues related to patient anatomy and surgical technique. Altered anatomy in revision cases, joint contractures and complex patterns of glenoid bone loss with unreliable landmarks are commonly encountered in this patient population. In such cases, directing the glenoid baseplate along an appropriate axis with sufficient bone stock for fixation may be a challenging intra-operative task.3 Surgical planning for these patients can be improved using three-dimensional (3D) reconstructions of CT scans, but recreating that same plan at surgery can be difficult.4,5 Computer navigation has been employed for this purpose, with promising results.6-8 However, computer-assisted glenoid implantation techniques use an intra-operative setup using a tracking system,6-9 with some disadvantages: instrumentation is cumbersome to use in the shoulder; pins used for array fixation may cause iatrogenic lesions such as fracture or neurovascular injury; registration of anatomical landmarks may be inaccurate; and the need for resetting may result in an increase in operative time of more than 20%.5,7 Finally, tracking devices may loosen, giving unreliable information.6 Patient-specific instrumentation has the potential to provide a similar level of accuracy as computer-assisted navigation, but without such problems or additional surgical steps. This type of pre-operative planning has grown in popularity across a wide range of orthopaedic subspecialties including total hip and knee arthroplasty, pelvic and acetabular procedures and spinal deformities, with varying degrees of success.1 It is the most recent development in this field, and its effectiveness in both the version and inclination planes of glenoid component placement has been demonstrated for both total anatomical and reverse shoulder arthroplasties.

[学科分类] 神经科学

[关键词] patient-specific instrumentation;PSI;shoulder;arthroplasty;arthritis;glenoid;prosthesis