These authors used commercially available software from 4 companies (Blueprint: Wright Medical, Memphis, TN, USA; GPS: Exactech, Gainesville, FL, USA; Materialise: DJO, Vista, CA, USA; and VIP: Arthrex, Naples, FL, USA) to evaluate 81 consecutive shoulder computed tomography scans obtained for preoperative planning purposes for shoulder arthroplasty. The results were compared to the analysis of 5 fellowship-trained sports medicine/shoulder surgeons.
Surgeon reliability was acceptable for version, inclination, and the relationship of the humeral head to the plane of the scapula .
Significant differences were found between surgeon and commercial software measurements in version, inclination, and the relationship of the humeral head to the plane of the scapula (not to be confused with glenohumeral subluxation). Note in the example below, the humeral head is centered in the glenoid (i.e. not subluxated), even though a substantial percentage of the humeral head lies posterior to the plane of the scapula.
The authors concluded that preoperative planning software for shoulder arthroplasty has limited agreement in measures of version, inclination, and the relationship of the humeral head to the plane of the scapula, whereas surgeons have high inter-reliability. They recommend that surgeons should be cautious when using commercial software planning systems and when comparing publications that use different planning systems to determine preoperative glenoid deformity measurements.
Comment: The authors point out that reliance on planning software to determine the type of procedure, the need for special implants, and the position of the components may lead to decisions different from what a surgeon would make. For example, it may lead some surgeons to change from an anatomic shoulder replacement to a reverse shoulder replacement or to use glenoid augmentation when it is not necessary. As they say, surgical decisions should be made based on intraoperative findings, preoperative plan, quality of patient tissue, surgeon experience, and evolving evidence-based outcomes associated with implant longevity and patient function.
From recent aviation history, we are all too aware of what happens when the pilot relinquishes control to a computer.
