title: The Use of an Electronic System for Soft Tissue Balancing in Primary Total Knee Arthroplasties: Clinical and Radiological Evaluation.
abstract: The eLibra® Dynamic Knee Balancing System (Synvasive Technology, Zimmer, Warsaw, IN) is an instrument designed to address the flexion stability during a TKA. It provides an objective measurement of the soft-tissue forces in the two compartments before the final cuts are made, allowing to obtain patient-specific rotational orientation of the femoral component. Between March 2010 and March 2012, the eLibra® system was used during the implantation of 75 TKAs in 75 patients at the author's institution. Preoperative and postoperative clinical assessment were evaluated using the Knee Society Score (KSS) and the Visual Analogical Scale (VAS). Radiographic evaluation was performed with weight-bearing radiographs in antero-posterior and lateral views in order to study the presence of radiolucencies. In a sample of 20 patients, representative of the population studied, the rotation of the femoral component was measured by two independent observers using the C-arm Cone Beam CT scan (XperCT/Allura FD20 angiography system; Philips, Best, Netherlands). At a mean follow-up of 42.3 months (29-54 months), three patients died from causes not related to the surgery. We had one case of aseptic loosening three years after surgery. None of the patients reported complications peri- or postoperatively. Clinical evaluation showed an improvement in KSS scoring, from preoperative means of 48.35 and 47.53 points for clinical and functional aspects, respectively, to postoperative means of 88.03 and 91.2 points, respectively (p<0.001 for both aspects). The current study demonstrates that the use of the eLibra® device is simple and reproducible. It could help surgeons objectively quantify ligament balance and perform soft tissue-guided resection in a reproducible way, resulting in better post-operative stability and reduced complications. The use of the postoperative cone beam computed tomography (CBCT), in a representative sample of patients, revealed a specific and optimal orientation of the femoral component with a mean of 2.18° of external rotation.
authors.affiliation: Division of Orthopedics and Traumatology, Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: D'Angelo
authors.affiliation: Division of Orthopedics and Traumatology, Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Puricelli
authors.affiliation: Division of Orthopedics and Traumatology, Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Binda
authors.affiliation: Division of Orthopedics and Traumatology, Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy.
authors.forename: Michele Francesco
authors.initials: MF
authors.lastname: Surace
authors.affiliation: Department of Radiology, University of Insubria, Varese, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Floridi
authors.affiliation: Division of Orthopedics and Traumatology, Department of Biology and Life Sciences, University of Insubria, Varese, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cherubino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000502:physiology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*