Scientific underpinnings of the clinical assessment of patellofemoral alignment.

Patellofemoral pain is a common condition with multiple risk factors. A common consideration in the aetiology of patellofemoral pain is mal-alignment of the patellofemoral joint, which in itself, also has many causes. Clinical assessment of patients with patellofemoral pain requires a variety of tests to ascertain the underlying pathophysiology. Patellofemoral mal-alignment is, therefore, of clinical importance during physical assessments by clinicians. A common method of clinical assessment of patellofemoral mal-alignment is the McConnell assessment. At present, there is a lack of scientific evidence to support the clinical outcome measures from the McConnell assessment method for patellofemoral alignment. Whilst some authors have looked to modify this method to increase the objectivity of the outcome measures, there remain concerns about the reliability of the McConnell assessment method, whether modified or not, and how this may inform appropriate treatment, rehabilitation and onward referral. The McConnell assessment of patellofemoral alignment was developed to provide a rationale for McConnell taping to realign the joint. Realignment of abnormal joint position should, therefore, reduce pain and provide accelerated progression of therapeutic interventions and rehabilitation. At present, scientific evidence for the effectiveness of McConnell taping to reduce pain and realign the patellofemoral joint lacks agreement. Therefore, the purpose of this research was to examine the clinical assessment of patellofemoral alignment, as proposed by McConnell, in providing measurements of alignment compared to more detailed methods of assessment via magnetic resonance imaging (MRI), and to determine if McConnell taping would affect pain alongside any changes in patellofemoral alignment. The first experimental chapter (3) explored the clinical and radiological assessment processes used by physiotherapists and sports therapists. The results revealed that 42% of physiotherapists and sports therapists used the McConnell assessment method, or a modified version by Herrington, during the clinical assessment to measure patellofemoral alignment. Experimental Chapter 4 tested a custom-made calliper designed to replicate and objectify the McConnell method of assessment. The calliper (named the Patellofemoral Calliper) was used to assess patellofemoral alignment in asymptomatic participants with the outcomes being compared to recognised MRI methods of patellofemoral alignment assessment. The results revealed statistically significant intra-tester reliability for the calliper, however, lacked clinically relevant agreement with an MRI method that replicated the McConnell assessment on the MRI images. In addition, the calliper did not provide statistically significant correlation coefficients to values of patellofemoral alignment derived from MRI. Experimental Chapter 5 explored osteoarthritic patellofemoral joints to determine if this population would have greater lateral alignment compared to participants from Chapter 4. The results highlighted increased lateral positioning in participants with osteoarthritis compared to an asymptomatic sample, confirmed via MRI. An observation from this study highlighted variability in the vertical axis of rotation of the femur during scanning that may have influenced the measurements that would be derived from clinical assessment. When the vertical axis of rotation was corrected to the posterior condylar line, the correlation between a clinical equivalent method of the McConnell method of assessment (derived from the scans to replicate the calliper used in Chapter 4) and the recognised alignment measures from MRI all improved. The result of the findings from Chapter 5 led to the experimental study in Chapter 6, whereby the Patellofemoral Calliper was tested on patients with patellofemoral pain and compared with MRI scans. However, during testing of the patellofemoral participants, the patient setup was given greater scrutiny, and the participant remained on the MRI scanner table for calliper testing. The results of this study saw improved agreement between the calliper and MRI derived measures, as well as improved correlation coefficients between the calliper and MRI alignment values. The final experimental chapter (7) investigated the effect of McConnell medialisation taping, compared to a placebo tape application, in reducing pain and altering patellofemoral alignment in patients with patellofemoral pain. The results revealed that pain was reduced in both the McConnell medialisation taping and the placebo taping methods. Additionally, one MRI assessment method identified a difference in patellofemoral alignment following McConnell medialisation tape, but not for the placebo taping. All other assessments for alignment were non-significant for McConnell medialisation tape and for the placebo tape. The results of the experimental studies in this thesis demonstrate that clinical assessment of patellofemoral joint alignment requires development of the patient setup to ensure reliable values can be obtained. Specifically, vertical axis orientation of the femur requires control to enable meaningful data from clinical assessment. This may enable greater reliance on the clinical assessment methods available, including the McConnell assessment, especially when modified to provide objective outcome measures. McConnell medialisation taping of the patellofemoral joint in patients with patellofemoral pain is supported by this research in providing immediate pain reducing effects. However, changes in patellofemoral alignment following McConnell medialisation taping are not identified as a modifiable variable