Browsing by Subject "Knee"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Publication
    Restricted
    Computed tomography-based patient-specific instrumentation loses accuracy with significant varus preoperative misalignment
    (Thieme Gruppe, 2020-09-08) León Muñoz, Vicente Jesús; López López, Mirian; Lisón Almagro, Alonso José; Martínez Martínez, Francisco; Santonja Medina, Fernando; Cirugía, Pediatría y Obstetricia y Ginecología
    Patient-specific instrumentation (PSI) has been introduced to simplify and make total knee arthroplasty (TKA) surgery more precise, effective, and efficient. We performed this study to determine whether the postoperative coronal alignment is related to preoperative deformity when computed tomography (CT)-based PSI is used for TKA surgery, and how the PSI approach compares with deformity correction obtained with conventional instrumentation. We analyzed pre-and post-operative full length standing hip-knee-ankle (HKA) X-rays of the lower limb in both groups using a convention > 180 degrees for valgus alignment and < 180 degrees for varus alignment. For the PSI group, the mean ( SD) pre-operative HKA angle was 172.09 degrees varus ( 6.69 degrees) with a maximum varus alignment of 21.5 degrees (HKA 158.5) and a maximum valgus alignment of 14.0 degrees. The mean post-operative HKA was 179.43 degrees varus ( 2.32 degrees) with a maximum varus alignment of seven degrees and a maximum valgus alignment of six degrees. There has been a weak correlation among the values of the pre- and postoperative HKA angle. The adjusted odds ratio (aOR) of postoperative alignment outside the range of 180 3 degrees was significantly higher with a preoperative varus misalignment of 15 degrees or more (aOR: 4.18; 95% confidence interval: 1.35–12.96; p ¼ 0.013). In the control group (conventional instrumentation), this loss of accuracy occurs with preoperative misalignment of 10 degrees. Preoperative misalignment below 15 degrees appears to present minimal influence on postoperative alignment when a CT-based PSI system is used. The CT-based PSI tends to lose accuracy with preoperative varus misalignment over 15 degrees.
  • Thumbnail Image
    Publication
    Open Access
    Patient-specific instrumentation accuracy evaluated with 3D virtual models
    (MDPI, 2021-04-01) León Muñoz, Vicente J.; Parrinello, Andrea; Manca, Silvio; Galloni, Gianluca; López López, Mirian; Martínez Martínez, Francisco; Santonja Medina, Fernando; Cirugía, Pediatría y Obstetricia y Ginecología
    There have been remarkable advances in knee replacement surgery over the last few decades. One of the concerns continues to be the accuracy in achieving the desired alignment. Patient-specific instrumentation (PSI) was developed to increase component placement accuracy, but the available evidence is not conclusive. Our study aimed to determine a PSI system’s three-dimensional accuracy on 3D virtual models obtained by post-operative computed tomography. We compared the angular placement values of 35 total knee arthroplasties (TKAs) operated within a year obtained with the planned ones, and we analyzed the possible relationships between alignment and patient-reported outcomes. The mean (SD) discrepancies measured by two experienced engineers to the planned values observed were 1.64° (1.3°) for the hip–knee–ankle angle, 1.45° (1.06°) for the supplementary angle of the femoral lateral distal angle, 1.44° (0.97°) for the proximal medial tibial angle, 2.28° (1.78°) for tibial slope, 0.64° (1.09°) for femoral sagittal flexion, and 1.42° (1.06°) for femoral rotation. Neither variables related to post-operative alignment nor the proportion of change between pre-and post-operative alignment influenced the patient-reported outcomes. The evaluated PSI system’s three-dimensional alignment analysis showed a statistically significant difference between the angular values planned and those obtained. However, we did not find a relevant effect size, and this slight discrepancy did not impact the clinical outcome.
  • Thumbnail Image
    Publication
    Open Access
    Patient-specific instrumentation in total knee arthroplasty
    (Taylor and Francis Group, Taylor and Francis, 2019-06-10) León Muñoz, Vicente J.; Martínez Martínez, Francisco; López López, Mirian; Santonja Medina, Fernando; Cirugía, Pediatría y Obstetricia y Ginecología
    Introduction: Total knee arthroplasty (TKA) is one of the most commonly performed orthopedic procedures. During the past decade, patient-specific instrumentation (PSI) has been commercially introduced in order to simplify and make TKA surgery more effective, precise and efficient than conventional mechanical instrumentation (CI) and computer-assisted surgery (CAS). Nevertheless, there are critical arguments against PSI for routine use. The aim of the current manuscript is to describe advantages and limitations of PSI for primary TKA. Areas covered: By means of a description of the available literature different aspects are discussed (accuracy, clinical and functional outcomes, operative time, blood loss, efficiency and costs). Expert opinion: Most publications do not claim a significant increase in PSI accuracy over CI, but they also do not postulate PSIs accuracy is worse either. Regarding clinical aspects, PSI did not appear to give any advantage over standard techniques although, equally, it did not appear to show any disadvantages. PSI seems to reduce operative time, could reduce perioperative blood loss and provides logistical benefits in the operation room. Further studies will be required to more thoroughly assess all the advantages and disadvantages of this promising technology as an alternative to CI and CAS.
  • Thumbnail Image
    Publication
    Restricted
    Patient-specific instrumentation makes sense in total knee arthroplasty
    (Taylor and Francis Group, 2022-08-03) León Muñoz, Vicente J.; López López, Mirian; Santonja Medina, Fernando; Cirugía, Pediatría y Obstetricia y Ginecología
    Introduction: Patient-specific instrumentation (PSI) for total knee arthroplasty (TKA) surgery was initially developed to increase accuracy. The potential PSI benefits have expanded in the last decade, and other advantages have been published. However, different authors are critical of PSI and argue that the advantages are not such and do not compensate for the extra cost. This article aims to describe the recently published advantages and disadvantages of PSI. Areas covered: Narrative description of the latest publications related to PSI in accuracy, clinical and functional outcomes, operative time, efficiency, and other benefits. Expert opinion: We have published high accuracy of the system, with a not clinically relevant loss of accuracy, significantly higher precision with PSI than with conventional instruments, and a high percentage of cases in the optimal range and similar to that obtained with computer-assisted navigation, greater imprecision for tibial slope, a significant blood loss reduction, and time consumption, an acceptable and non-significant increase in the cost per procedure, and no difference in complications during hospital admission and at 90 days. We think that PSI will not follow the Scott Parabola and that it will continue to be a valuable type of device in some instances of TKA surgery.
  • Thumbnail Image
    Publication
    Restricted
    Reliability of the posterior condylar offset
    (Wiley, 2022-08) León Muñoz, Vicente J.; Parrinello, Andrea; Galloni, Gianluca; Lisón Almagro, Alonso J; López López, Mirian; Martínez Martínez, Francisco; Santonja Medina, Fernando; Cirugía, Pediatría y Obstetricia y Ginecología
    The posterior condylar offset (PCO) has been proposed as a determinant of a postoperative range of motion after total knee arthroplasty, although there is no consensus. This study aimed to demonstrate the error introduced by forcing the femoral rotation to overlap both condyles for the “true” lateral X‐ray projection for the PCO measurement. We hypothesize that the angular discrepancy between the posterior femoral cortical reference plane and the posterior condylar axis plane due to rotation invalidates the acquisition of reliable measurements on X‐rays. We have measured the PCO in 50 “true” lateral X‐rays and compared it with the medial and lateral condyles PCO's assessed on a computed tomography‐scan‐based three‐ dimensional (3D) model of each knee. PCO based on the 3D imaging differed significantly between the medial (25.8 ± 3.67 mm) and lateral (16.59 ± 2.92 mm) condyle. Three‐dimensional PCO values differ significantly from those determined in the radiographic studies. Also, the mean values of the medial and lateral condyle PCO measurements differed significantly (p < 0.001) with all PCO measurements on radiographs. We have identified a difference between the posterior cortical plane and the posterior condylar axis projections, both on the axial plane with a mean value of 11.23° ± 3.64°. Our data show an interplane discrepancy angle between the posterior femoral diaphyseal cortical and the posterior condylar axis plane (due to the femur's necessary rotation to overlap both condyles) may invalidate the 2D X‐ray PCO assessment as a reliable measurement.
  • Thumbnail Image
    Publication
    Open Access
    Revision of total knee arthroplasty with the use of patient-specific instruments: an alternative surgical technique
    (Taylor and Francis Group, 2020-08-09) León Muñoz, Vicente J.; Parrinello, Andrea; López López, Mirian; Martínez Martínez, Francisco; Santonja Medina, Fernando; Cirugía, Pediatría y Obstetricia y Ginecología
    Introduction: Accuracy in the placement of components in revision total knee arthroplasty (R-TKA) surgery is sometimes challenging. The applicability of patient-specific instruments (PSI) in knee surgery has progressively expanded to types of surgery other than primary arthroplasty. Could this assistive technology be used to facilitate accurate R-TKA surgery? The aim of the current manuscript is to describe this new application of PSI for revision of TKA-to-TKA and to provide a step-by-step technical guideline for use. Areas covered: We will describe the application and a detailed description of PSI technology to TKA revision surgery, step-by-step, from CT images acquisition for preoperative planning and PSI blocks production to the surgery. Expert commentary: The system can facilitate the accomplishment of the bony cuts for optimal implant placement and that can be useful in minimally altering the femoral and the tibial joint line. It is obvious that technology alone will not replace surgical skill and that accuracy of the system will also depend on the quality of the CT images and the ability of the software to prevent metal artifacts. Despite that, our initial results are promising and prove that the concept of applying PSI technology to the R-TKA surgery is feasible.