Browsing by Subject "Patient specific instrumentation"

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    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.
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    Impact of surgical instrumentation on hospital length of stay and cost of total knee arthroplasty
    (Taylor and Francis, 2020-06-21) León Muñoz, Vicente J.; López López, Mirian; Martínez Martínez, Francisco; Santonja Medina, Fernando; Cirugía, Pediatría y Obstetricia y Ginecología
    Background: We aimed to analyze the impact of two different types of surgical instrumentation (conventional manual instrumentation (CI) and patient-specific instrumentation (PSI)) on length of stay (LOS) and objectify differences in cost. We hypothesized that there are no differences in the LOS and cost due to the instrumentation system used. Research design and methods: LOS was registered using inpatient admission data provided by the Institutional Management Control Department. We recorded the costs associated with each procedure that could be influenced by the use of one system or another during the in-hospital stay. We conducted a prospectively single-center cohort study of 305 TKAs. Surgery was performed with conventional CI in 122 cases and with PSI in 183 cases. Results: The mean LOS for the CI group was 4.29 days (SD 1.65) and 4.22 days (SD 1.26), for the PSI group. No significant difference among both instrumentation systems was obtained. When comparing global costs, the mean cost was slightly higher (without a significant difference) for the PSI cases (€3110.24 vs. €2852.7 for the CI cases). Conclusions: LOS and overall cost, in hospitals with a low annual TKA surgery volume, are unrelated to conventional or patient-specific instrumentation.