Patient-Specific Instrumentation in Total Knee Arthroplasty: A Review

Abstract

Recently, patient-specific approaches to total knee arthroplasty (TKA) have been introduced, in which preoperative imaging (plain radiographs, computed tomography [CT], and magnetic resonance imaging [MRI]) are used to manufacture cutting blocks specific to a patient's anatomy. Proposed benefits of patient-matched cutting blocks include a decrease in operative time, instrument trays required, and the ability to preoperatively plan a patient's component size, position, and alignment. In addition, an improvement in postoperative mechanical alignment is expected, without violation of the intramedullary (IM) canal. However, questions remain regarding patient outcomes and the cost-effectiveness associated with patientspecific cutting block technology. This article will review the evolution of surgical techniques in TKA, the development of patient-specific cutting blocks, surgical considerations, and the literature associated with this new technology. An Evolution of Surgical TechniquesAlthough TKA has been a tremendously successful procedure in the management of degenerative joint disease, tibial and femoral component malalignment remains a significant concern. Berend et al has shown that a tibial varus alignment of >3 degrees increased the odds of implant failure and medial bone collapse by roughly 17 times, emphasizing the importance of accurate tibial component positioning on TKA survivorship. 1 Recently, Ritter et al, in a review of 6070 TKAs, noted that the risk of aseptic failure increased if the orientation of the tibial component was <90 degrees relative to the tibial axis, and the orientation of the femoral component was >8 degrees of valgus (failure rate 8.7%). In addition, they noted that "correction" of varus or valgus malalignment of the first implanted component by placement of the second component, to attain a neutral tibiofemoral alignment, was associated with increased failure rates, indicating that optimal positioning of both the femoral and tibial components is crucial. 2 With the increasing prevalence of total joint replacements performed in the United States, the projected increase in revision total knee surgery has been estimated to be 412% by the year 2030. Therefore, improved surgical techniques to prevent malalignment may prove cost-effective. 3 Currently, the instruments most commonly used in TKA are an extramedullary (EM) alignment guide for the tibial resection, and an IM alignment guide for the distal femoral Keywords ► total knee arthroplasty ► patient-specific instrumentation ► alignment ► cost-effectiveness AbstractRecently, patient-specific approaches to total knee arthroplasty (TKA) have been introduced, in which preoperative imaging (plain radiographs, computed tomography, and magnetic resonance imaging) are used to manufacture cutting blocks specific to a patient's anatomy. Proposed benefits of patient-matched cutting blocks include a decrease in operative time, instrument trays required, and the ability to preoperatively plan a patient's component size, position, and alignment. In ...

Postoperative accuracy analysis of three-dimensional corrective osteotomy for cubitus varus deformity with a custom-made surgical guide based on computer simulation

“…to that for total knee arthroplasty, 23,35 ranging from $650 to $1200 USD. We expect that technologic development will soon reduce the time and cost required.…”

Patient-specific instrumentation improved axial alignment of the femoral component, operative time and perioperative blood loss after total knee arthroplasty

“…In recent years, the introduction of patient-specific instrumentation (PSI) has gradually become popular among orthopaedic surgeons and is expected to improve component alignment and positioning, postoperative functional recovery, and patient satisfaction [8, 35]. The fundamental processes are preoperative computed tomography (CT) and/or magnetic resonance imaging, computer-aided three-dimensional (3D) reconstruction, 3D printing from a disposable template, accurate intraoperative placement and osteotomy.…”

Radiographic Outcomes of Preoperative CT Scan–Derived Patient-Specific Total Ankle Arthroplasty

“…19 Proposed benefits include improved implant alignment, decreased operative time, more efficient surgical planning, and lower cost. 18 In recent years, preoperative computed tomography (CT) scan-derived patient-specific plans and guides (PROPHECY, Wright Medical Technology, Memphis, TN) have been developed for total ankle arthroplasty (TAA) and approved by the Food and Drug Administration. Cadaveric study results have shown that these patient-specific guides can provide reliable and reproducible placement of TAA implants to within 2 degrees of preoperative plans.…”