In vitro biomechanical comparison of partial, combined partial, and total knee arthroplasty
File(s)
Author(s)
Dandridge, Oliver
Type
Thesis
Abstract
Partial (PKA) and Combined Partial Knee Arthroplasty (CPKA) are alternative treatments of knee osteoarthritis that aim to improve outcomes and satisfaction compared to Total Knee Arthroplasty (TKA). Despite growing use and evidence of preferable results, partial knee approaches remain underused relative to compartmental disease distributions. This thesis explored in vitro biomechanical explanations for functional advantages of (C)PKA.
A validation of cadaveric protocols addressed concerns about variability, ensuring certain procedures were not disadvantaged. Testing order effects were assessed for two biomechanical datasets, validating repeated-measures protocols with multiple implant states, providing confidence in methods used globally by engineers and surgeons.
A repeated-measures cadaveric study assessed biomechanics of (C)PKA and TKA compared to intact knees, measuring extensor efficiency, kinematics, and anteroposterior stability. (C)PKA better restored biomechanics compared to TKA, which reduced extensor efficiency up to 50%, increased anteroposterior laxity up to 25mm, and altered kinematics.
A novel Patellar Tendon Moment Arm (PTMA) measurement framework was developed to explain extensor efficiency differences between (C)PKA and TKA. The long-standing problem of PTMA measurement at limits of motion was solved by applying validated data-smoothing. Native PTMA variation was assessed using the framework, demonstrating size-independent variation, which might improve arthroplasty designs and techniques.
Effects of implant position in Patellofemoral Arthroplasty (PFA) were assessed in a repeated-measures cadaver model. Controlled, specimen-specific apparatus allowed patellar and femoral implant position alteration, whilst minimising experimental variance. PFA was able to restore native biomechanics and patellar implant position altered patellofemoral biomechanics in a predictable manner, showing patellar cut orientation alters the position of the patella dynamically, providing information useful for improving patellar resurfacing.
(C)PKA demonstrates biomechanical improvements over TKA, making it a viable alternative treatment of knee osteoarthritis, especially for patients with higher functional requirements. Improved management of the patella in knee arthroplasty may provide a useful means to improve outcomes overall.
A validation of cadaveric protocols addressed concerns about variability, ensuring certain procedures were not disadvantaged. Testing order effects were assessed for two biomechanical datasets, validating repeated-measures protocols with multiple implant states, providing confidence in methods used globally by engineers and surgeons.
A repeated-measures cadaveric study assessed biomechanics of (C)PKA and TKA compared to intact knees, measuring extensor efficiency, kinematics, and anteroposterior stability. (C)PKA better restored biomechanics compared to TKA, which reduced extensor efficiency up to 50%, increased anteroposterior laxity up to 25mm, and altered kinematics.
A novel Patellar Tendon Moment Arm (PTMA) measurement framework was developed to explain extensor efficiency differences between (C)PKA and TKA. The long-standing problem of PTMA measurement at limits of motion was solved by applying validated data-smoothing. Native PTMA variation was assessed using the framework, demonstrating size-independent variation, which might improve arthroplasty designs and techniques.
Effects of implant position in Patellofemoral Arthroplasty (PFA) were assessed in a repeated-measures cadaver model. Controlled, specimen-specific apparatus allowed patellar and femoral implant position alteration, whilst minimising experimental variance. PFA was able to restore native biomechanics and patellar implant position altered patellofemoral biomechanics in a predictable manner, showing patellar cut orientation alters the position of the patella dynamically, providing information useful for improving patellar resurfacing.
(C)PKA demonstrates biomechanical improvements over TKA, making it a viable alternative treatment of knee osteoarthritis, especially for patients with higher functional requirements. Improved management of the patella in knee arthroplasty may provide a useful means to improve outcomes overall.
Version
Open Access
Date Issued
2023-03-08
Date Awarded
2024-02-01
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
van Arkel, Richard
Cobb, Justin
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)