Study 1 is to determine if muscle strength and dynamic and postural stability are compromised in patients with severe hip or knee Osteoarthritis (OA) and in patients after THA and TKA. Study 2 is to quantify the effect of THA and TKA on muscle strength and dynamic and postural stability.
Postural stability is defined as the ability to maintain the body's centre of gravity within the limits of stability as determined by the base of support. It is further divided in static and dynamic stability involving the ability of maintaining a base of support while standing or completing a functional Task. The importance of postural stability is accepted as a factor predicting falls and affecting the ability to perform activities of daily living. Despite of reported strength deficits and the importance of balance, to date the potential contribution of strength deficits in patients before and after Total Hip Arthroplasty (THA) or Total Knee Arthroplasty (TKA) to compromised balance ability is unknown. Furthermore, the role of preoperative muscle function on functional outcome of THA and TKA is poorly understood. A correlation between compromised preoperative muscular function and postoperative outcome would suggest that preoperative physical therapy may be critical for preserving the muscular status and may help explain reported poorer outcome after late treatment when muscular function has already deteriorated. The project includes two studies differing in design and primary and secondary objectives but with overlapping patient populations. Study 1 will include all five groups, and there is only one visit by the participant (visit A). Study 2 will include only patients from groups 3 and 4. Three assessments will be performed: preoperatively (visit 1), 6 weeks postoperatively (visit 2) and 1 year postoperative (visit 3). Visit 1 will be identical to visit A in study 1 in these two patient groups.
Study Type
OBSERVATIONAL
Enrollment
130
Muscle strength in knee flexion and extension and hip abduction will be tested using using a dynamometer (Biodex System 4 Pro: Biodex Medical Systems, Shirley, NY, USA)
Instrumented gait analysis on an overground walkway with two embedded force plates (Kistler force plate 9260AA6, Kistler AG, Winterthur, Switzerland; sampling rate 2400 Hz) and on a treadmill with an embedded plantar pressure plate (h/p/cosmos, Zebris FDM-T, Isny, Germany)
The overall stability index (OSI) will be assessed using the Biodex Balance System SD (Biodex Medical Systems, Inc., Shirley, NY, USA) and is determined by the variance in platform displacement from the horizontal plane.
Department of Orthopaedics and Traumatology, University Hospital Basel
Basel, Switzerland
Muscle strength (Study 1)
For the knee, maximum isokinetic flexion and extension torques will be collected between full extension and 90° flexion at a movement speed of 60°/s (5 repetitions) and 240°/s (5 repetitions).For the hip, maximum abduction torques will be measured isometrically (5 repetitions) in a standing position. Maximum joint torques in each movement direction will be recorded for each joint and normalized to body weight (study group 1 to 5)
Time frame: single point measurement at Visit A (week 0)
Change in Muscle strength (Study 2)
For the knee, maximum isokinetic flexion and extension torques will be collected between full extension and 90° flexion at a movement speed of 60°/s (5 repetitions) and 240°/s (5 repetitions).For the hip, maximum abduction torques will be measured isometrically (5 repetitions) in a standing position. Maximum joint torques in each movement direction will be recorded for each joint and normalized to body weight (study group 3 and 4)
Time frame: Three assessments will be performed: preoperatively (visit 1), 6 weeks postoperatively (visit 2) and 1 year postoperative (visit 3).
Postural stability (Study 1)
The overall stability index (OSI) will be assessed using the Biodex Balance System SD. A high stability index represents the angular excursion of the subject's center of gravity and is indicative of a high degree of movement during a test (i.e.poor balance). (study group 1 to 5)
Time frame: single point measurement at Visit A (week 0)
Change in postural stability (Study 2)
The overall stability index (OSI) will be assessed using the Biodex Balance System SD. A high stability index represents the angular excursion of the subject's center of gravity and is indicative of a high degree of movement during a test (i.e.poor balance).(study group 3 and 4)
Time frame: Three assessments will be performed: preoperatively (visit 1), 6 weeks postoperatively (visit 2) and 1 year postoperative (visit 3).
Dynamic stability (Study 1)
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Overall health will be assessed using the EQ-5D-5L health questionnaire
Site specific pain and function will be assessed with the Hip Osteoarthritis Outcome Score (HOOS) and Knee Injury and Osteoarthritis Outcome Score (KOOS) depending on the affected joint (hip or knee).
Surface electrodes (Ag/AgCl, Noraxon, U.S.A. Inc., Scottsdale, AZ, USA: 10 mm diameter, 22 mm inter-electrode distance) will be placed bilaterally on glutaeus medius, vastus medialis, semitendinosus, tibialis anterior, gastrocnemius medialis, and peroneus longus muscles. Periods of muscle activity will be defined as intensity above 2 Standard Deviation (SD) of the resting Electromyography (EMG) signal. Duration of overlapping muscle activity between agonists and antagonists normalized to one gait cycle or of a balance test, respectively, will be determined.
Passive range of motion will be assessed for ankle plantar-/dorsiflexion, knee flexion/extension and hip flexion/extension, ab/adduction, internal/external rotation using goniometers and recorded in degrees. The range between two maxima will be recorded.
Instrumented gait analysis on an overground walkway to compute step width for each step from a pressure plate built into the treadmill (study group 1 to 5)
Time frame: single point measurement at Visit A (week 0)
Change in dynamic stability (Study 2)
Instrumented gait analysis on an overground walkway to compute step width for each step from a pressure plate built into the treadmill (study group 3 and 4)
Time frame: Three assessments will be performed: preoperatively (visit 1), 6 weeks postoperatively (visit 2) and 1 year postoperative (visit 3).