Customization of cutting blocks: Can this address the problem?

Abstract

Recent literature has challenged the notion that neutral coronal alignment is a requirement for long-term survivorship of TKAs. However a preponderance of classic and contemporary evidence supports increased failure rates with malalignment, especially varus. Patient-specific custom cutting guides are an attractive alternative to traditional instrumentation and computer navigation in achieving accurate alignment of total knee arthroplasties. The logistical benefits include possible decreased operating room time, decreased turnover time, less time spent sterilizing and preparing trays, less inventory, less strain on surgical technicians and nurses, and no capital cost associated with computer navigation. Patient benefits include potentially less tourniquet time, less surgical exposure, no requirement of intramedullary canal preparation, and improved mechanical alignment, which may translate to increased implant longevity. Surgeon benefits include potentially more accurate landmark registration than computer navigation, more efficient surgery, decreased intraoperative stress due to less required decision making, and the ability to perform more surgeries due to time saved.

Applications of medical rapid prototyping assisted customized surgical guides in complex surgeries

“… CSG is quick and simple to use without any specific skill, easy to handle and cost-effective (Khan et al , 2013); CSG directly transfers VSP into actual surgery thereby simplifying the surgery, reduces surgical time and improves surgical accuracy without damaging neighboring tissues (Fantini et al , 2013); it eliminates the need of complex equipments and the time-consuming procedures in the operating room, as well as reduces inventory needed, strain on surgical technicians and nurses (Lombardi and Frye, 2012); it eliminates the need of fluoroscopy that significantly reduces radiation exposure to the members of the surgical team and patient (Lu et al , 2009); it provides a clinically relevant smoothness in bone cutting and drilling that increases accuracy in implant placement (Cartiux et al , 2013); it eliminates the inaccuracies commonly associated with traditional surgery planning; and it eliminates surgical steps such as intraoperative measuring, determining the tumor or deformity position, the use of bulky intermediate splints, simplifying the execution (Polley and Figueroa et al , 2012). …”

Review Article: Patient-Specific versus Standard Instrumentation for Total Knee Arthroplasty

“…Neutral coronal alignment is essential for long-term TKA success; poor alignment is a risk factor for implant failure. 7,10,[19][20][21][22][23] The most important risk factors reported for medial bone collapse (secondary to tibial component failure) were tibial varus alignment of >3º, BMI of >33 kg/m 2 , and an overall varus mechanical alignment (HKA angle). 21 The failure rate increases 4.6 fold for each degree of mechanical varus, and increases to 69 fold for all >3º outliers.…”

“…6 The benefits of PSI include shortened operative time and improved mechanical alignment; this leads to improved implant longevity and clinical outcomes. 6,7 This study reviewed 12 studies that compared PSI with standard instrumentation (SI) for TKA in terms of coronal alignment and operation time.…”

Automating the design of resection guides specific to patient anatomy in knee replacement surgery by enhanced 3D curvature and surface modeling of distal femur shape models

“…However, in resurfacing interventions, limited to one or even two compartments (e.g. Journey-Deuce implant by Smith&Nephew), where the anterior and posterior ligaments are spared, the use of personalized resection guides is of true benefit and automated planning systems can be utilized more extensively with surgical advantages [4,5,47].…”