Date of Award
Master of Science (MS)
Melinda Harman, PhD
Yongren Wu, PhD
John DesJardins, PhD
Total knee replacement (TKR) is generally considered a successful treatment for musculoskeletal disorders of the knee. However, as many as 20% of patients report some dissatisfaction in their physical function after TKR. And approximately 50% of early revisions needed to address conditions related to component alignment and soft tissue tension to stabilize the knee. During TKR, surgeons manually perform passive range of motion (ROM) assessments to gain feedback perceived as tension in ligaments and other soft tissues. Such assessments are highly subjective and rely on the surgeon's perception of soft tissue tension rather than quantitative objective means. The variability in applied loads during passive ROM assessments is poorly understood.
The broad objective of this thesis was to analyze variations in surgeon-applied loads during passive ROM assessments following TKR on individual cadaver knees. There were three specific aims: 1) experimentally measure surgeon-applied loads during passive ROM of cadaver limbs implanted with TKR; 2) statistically analyze intra-specimen and inter-specimen repeatability in surgeon-applied loading profiles; and 3) process surgeon-applied external loads for input into computational models used to calculate knee ligament tensions.
Three cadaveric lower limbs were implanted with TKR and mounted into a custom-designed knee rig instrumented to simulate and measure applied loads and kinematics during passive ROM assessments performed by an experienced orthopaedic surgeon. It was hypothesized that intra-specimen cycles would not be a significant factor affecting the applied loading profiles. It was hypothesized that inter-specimen differences would be a significant factor affecting applied loading profiles. The 4 degrees of freedom tracked (varus-valgus, anterior-posterior, compressive load, and internal-external rotation), external loads applied by the surgeon were highly consistent within the five cycles per trial and the 95% confidence interval varied within 0.5Nm for applied moments and within 5N for applied compressive forces. It was concluded that intra-specimen cycles were not a factor affecting the load profiles and inter-specimen differences were a significant factor affecting applied loading profiles. Variations in external loads during intra-operative assessments of component alignment and soft tissue tension can impact clinical decisions and outcomes. In a biomechanical sense, new technologies and sensors meant to aid intra-operative decisions need to accommodate variability in assumed load magnitudes during passive ROM assessments.
Bakle II, CJ, "Variations in Surgeon-Applied Loads During Passive Range of Motion Following Total Knee Replacement With Relevance To Computational Modeling" (2022). All Theses. 3874.