Doctor of Philosophy / The aim of the work presented in this thesis was to examine the associations between the kinematics of the knee characterised by the tibiofemoral contact pattern, and degenerative change, in the context of anterior cruciate ligament (ACL) injury. While the natural history of degenerative change following knee injury is well understood, the role of kinematics in these changes is unclear. Kinematics of the knee has been described in a variety of ways, most commonly by describing motion according to the six degrees of freedom of the knee. The advantage of mapping the tibiofemoral contact pattern is that it describes events at the articular surface, important to degenerative change. It was hypothesised that the tibiofemoral contact pattern would be affected by injury to the knee. A model of ACL injury was chosen because the kinematics of the knee have been shown to be affected by ACL injury, and because the majority of chronic ACL-deficient knees develop osteoarthritis, the associations between kinematics and degenerative change could be explored. A technique of tibiofemoral contact pattern mapping was established using MRI, as a quantifiable measure of knee kinematics. The tibiofemoral contact pattern was recorded from 0º to 90º knee flexion while subjects performed a leg-press against a 150N load, using sagittal magnetic resonance imaging (MRI) scans. The technique was tested and found to be reliable, allowing a description of the tibiofemoral contact pattern in 12 healthy subjects. The tibiofemoral contact patterns of knee pathology were then examined in a series of studies of subjects at a variety of stages of chronicity of ligament injury and osteoarthritis. Twenty subjects with recent ACL injury, 23 subjects with chronic ACL deficiency of at least 10 years standing, and 14 subjects with established osteoarthritis of the knee were recruited. The 20 subjects with recent ACL injury were examined again at 12 weeks and 2 years following knee reconstruction. The tibiofemoral contact patterns were examined for each group of subjects and the associations between changes in the contact patterns and evidence of joint damage explored. Evidence of joint damage and severity of osteoarthritis were recorded from xrays, diagnostic MRI, operation reports and bone densitometry at the tibial and femoral condyles of the knee. Each of the three groups with knee pathology exhibited different characteristics in the tibiofemoral contact pattern, and these differences were associated with severity of joint damage and osteoarthritis. The recently ACL-injured knees demonstrated a tibiofemoral contact pattern that was posterior on the tibial plateau, particularly in the lateral compartment. Those with chronic ACL deficiency demonstrated differences in the contact pattern in the medial compartment, associated with severity of damage to the knee joint. Osteoarthritic knees showed reduced femoral roll back and longitudinal rotation that normally occur during knee flexion. Two years following knee reconstruction there was no difference between the contact pattern of the reconstructed and healthy contralateral knees. This technique of tibiofemoral contact pattern mapping is sensitive to the abnormal characteristics of kinematics in ligament injury and osteoarthritis. This is the first time the tibiofemoral contact characteristics of chronic ACL-deficient and osteoarthritis knees have been described and links examined between tibiofemoral contact patterns and degenerative change.

Doctor of Philosophy / The aim of the work presented in this thesis was to examine the associations between the kinematics of the knee characterised by the tibiofemoral contact pattern, and degenerative change, in the context of anterior cruciate ligament (ACL) injury. While the natural history of degenerative change following knee injury is well understood, the role of kinematics in these changes is unclear. Kinematics of the knee has been described in a variety of ways, most commonly by describing motion according to the six degrees of freedom of the knee. The advantage of mapping the tibiofemoral contact pattern is that it describes events at the articular surface, important to degenerative change. It was hypothesised that the tibiofemoral contact pattern would be affected by injury to the knee. A model of ACL injury was chosen because the kinematics of the knee have been shown to be affected by ACL injury, and because the majority of chronic ACL-deficient knees develop osteoarthritis, the associations between kinematics and degenerative change could be explored. A technique of tibiofemoral contact pattern mapping was established using MRI, as a quantifiable measure of knee kinematics. The tibiofemoral contact pattern was recorded from 0º to 90º knee flexion while subjects performed a leg-press against a 150N load, using sagittal magnetic resonance imaging (MRI) scans. The technique was tested and found to be reliable, allowing a description of the tibiofemoral contact pattern in 12 healthy subjects. The tibiofemoral contact patterns of knee pathology were then examined in a series of studies of subjects at a variety of stages of chronicity of ligament injury and osteoarthritis. Twenty subjects with recent ACL injury, 23 subjects with chronic ACL deficiency of at least 10 years standing, and 14 subjects with established osteoarthritis of the knee were recruited. The 20 subjects with recent ACL injury were examined again at 12 weeks and 2 years following knee reconstruction. The tibiofemoral contact patterns were examined for each group of subjects and the associations between changes in the contact patterns and evidence of joint damage explored. Evidence of joint damage and severity of osteoarthritis were recorded from xrays, diagnostic MRI, operation reports and bone densitometry at the tibial and femoral condyles of the knee. Each of the three groups with knee pathology exhibited different characteristics in the tibiofemoral contact pattern, and these differences were associated with severity of joint damage and osteoarthritis. The recently ACL-injured knees demonstrated a tibiofemoral contact pattern that was posterior on the tibial plateau, particularly in the lateral compartment. Those with chronic ACL deficiency demonstrated differences in the contact pattern in the medial compartment, associated with severity of damage to the knee joint. Osteoarthritic knees showed reduced femoral roll back and longitudinal rotation that normally occur during knee flexion. Two years following knee reconstruction there was no difference between the contact pattern of the reconstructed and healthy contralateral knees. This technique of tibiofemoral contact pattern mapping is sensitive to the abnormal characteristics of kinematics in ligament injury and osteoarthritis. This is the first time the tibiofemoral contact characteristics of chronic ACL-deficient and osteoarthritis knees have been described and links examined between tibiofemoral contact patterns and degenerative change.