In vivo kinematics and kinetics of a bi‐cruciate substituting total knee arthroplasty: A combined fluoroscopic and gait analysis study

Abstract

After total knee arthroplasty, changes in articular surface geometry, soft tissue treatment, and component alignment can alter normal lower limb function. The guided motion bi-cruciate substituting prosthesis was designed specifically to restore physiological knee joint motion. We determined whether this design could in vivo normal kinematics and kinetics, not only at the replaced knee, but also throughout both lower limbs. Sixteen patients (4 male, 12 female, mean age of 68.2 years with a range from 58 to 79 years) with primary knee osteoarthritis were implanted with the bi-cruciate substituting prosthesis. At 6-month follow-up, knee joint kinematics was assessed by video-fluoroscopy during stair-climbing, chair-rising/sitting, and step-up/down. Lower limb overall function was also assessed on the same day by standard gait analysis with simultaneous electromyography during level walking. By video-fluoroscopy, mean anteroposterior translations between femoral and tibial components during the three motor tasks were 9.7 AE 3.0, 10 AE 2.6, and 6.9 AE 3.5 mm on the medial compartment, and 14.3 AE 3.5, 18.5 AE 3.0, and 13.9 AE 3.8 mm on the lateral compartment, respectively. Axial rotation ranged from 5.68 to 26.28. Gait analysis revealed restoration of nearly normal walking patterns in most patients. This rare combination of measurements, i.e., accurate rotation-translation at the replaced knee and complete locomotion patterns at both lower limb joints, suggested that bi-cruciate substituting arthroplasty can restore physiological knee motion and normal overall function. ß

Design and kinematics in total knee arthroplasty

“…Fifteen patients from the Scorpio NRG group [18] and 16 from the Journey BCS [12] group were analysed postoperatively at six months of follow-up by video fluoroscopic analysis during stair climbing, chair rising/sitting and step up/ down. For stair climbing, three 21-cm-high steps were used; to assess stepping up and down, only the first step was used, and four up/down cycles were performed in a single repetition.…”

“…For the rising and sitting exercise, chair height was set specifically for each patient in order for him or her to begin with the knee flexed at about 80°. Data collection and analysis procedures were previously discussed [12,18,19] and included the use of a standard fluoroscope (digital remote-controlled diagnostic Alpha90SX16, CAT Medical System, Rome, Italy). Three-dimensional prostheses component positions and orientations were obtained from each fluoroscopic image by an iterative procedure using a CAD-model-based shape-matching technique [20].…”

“…Contact-line rotation, defined as rotation of the line connecting the medial and lateral CP with respect to the mediolateral axis on the tibial transverse plane, was calculated for each flexion angle, but here, it is reported over predefined flexion angles with 10°increments, starting from 0°. For each predefined angle, the corresponding contact positions were taken from each trial of each patient, and then averaged [12,18].…”

“…However, in vivo kinematic pattern studies in patients undergoing TKA demonstrated a considerable variation from the normal knee [10]. Different TKA design solutions for simulating physiological knee kinematics were thus investigated using a guided tibiofemoral motion with asymmetric spine-cam mechanism and an anatomic geometry of tibiofemoral articulation, showing axial rotation patterns similar to those of the normal knee [11,12]. Although PS fixed-bearing knee implants were thought to all have similar kinematic and kinetic patterns, reports show differing incidences and magnitudes of posterior femoral rollback (PFR) and axial rotation when comparing different designs [13,14].…”

CORR Insights®: Patient Activity After TKA Depends on Patient-specific Parameters

“…The development of new design features will continue and laboratory efforts assessing in vivo kinematics and kinetics of the new designs will continue to be essential [1,3,5,7]. However, using today's available electronic technology to assess actual performance during daily activities should soon be possible in every surgeon's office.…”