Rupture of the anterior cruciate ligament (ACL) is a common and disabling sporting injury resulting in an unstable knee joint that limits many aspects of activity, and in the long term may lead to osteoarthritis (OA). Its incidence and cost emphasise the importance of scientifically determining the optimal treatment programs available. A thorough understanding of the deficits following ACL injury and surgery is pivotal to treatment and an appreciation of individual differences is the cornerstone to optimizing recovery.
The studies reported within this thesis focused upon the identification and resolution of deficits as well as short and long term outcomes associated with a chronic injury to the ACL and its subsequent reconstruction, and on the consideration of effective approaches to their prevention and management through surgery and rehabilitation.
Importantly, patients from only one surgeon were evaluated prospectively pre-surgery and post-surgery and over an extended follow-up period. This contrasts with most past ACL studies that have been cross sectional rather than longitudinal and in which patients have been drawn from several surgeons.
This thesis described both the orthopaedic (biomechanical) deficits resulting from a chronic complete tear of the ACL, such as loss of range of motion (ROM), a marked deficit in quadriceps strength on the injured side, and a decrease in knee joint stability, as well as the neurophysiological deficits, such as alterations in proprioception and balance. It clarified the relationship between those impairments and joint reposition sense and functional performance. Significantly, a consistent relationship was revealed between strength of both the quadriceps and the hamstring muscles and functional performance.
By initially identifying deficits in these areas, further studies were able to determine the effectiveness of a targeted 'controlled' quadriceps emphasized physiotherapy program both pre-surgery and post-surgery in the prevention or resolution of deficits, as well as to assess the value in improving functional stability of adding a specific proprioceptive enhanced physiotherapy program to the quadriceps emphasized program offered over 5-6 months. In addition, the relative influence of two harvest sites for ACL reconstruction on the identified muscle and knee joint deficits and on functional performance in the short, medium and long term were evaluated to assist the physiotherapist in targeting assessment and treatment.
This study has provided a unique opportunity to contribute to the body of knowledge relating to the development of osteoarthritis after ACL reconstruction. Factors identified included menisectomy, chondral damage and, in the case of patellofemoral OA, the age of the patient at the time of surgery and the ratio of quadriceps to hamstring strength. This information offers guidance in regard to approaches to surgery and physiotherapy in helping to control the incidence of such an outcome associated with chronic ACL injury and subsequent reconstruction.
Overall, this thesis has made a substantial contribution to the understanding of the impact of chronic ACL injury, and has offered some informed direction as to effective approaches to its management.