In 1995 in the Journal of Skeletal Radiology the article “CT determination of tibial tubercle lateralization in patients presenting with anterior knee pain” was published. My astute Perth colleagues recognised the significance of this article and drew it to my attention on one of my regular visits to my training home town. For me, this serendipity was very significant. The principles that I have used have not changed in the last twelve years and hopefully sharing this experience may be helpful to you.
20° of flexion is the critical point for assessment of patella malalignment. Once the patella is engaged in the trochlear groove only gross malalignment can be recognised. The study of 50 subjects with asymptomatic knees without patella problems establish that patella tubercule lateralisation averages 7mms. in an asymptomatic human population. Patella tubercule lateralization of 9mms. or more identifies accurately patients with patellofemoral malalignment with the specificity of 95% and sensitivity of 85% Combined with a 90° lateral x-ray this examination can be used to plan surgery and provide predictable outcomes. It can also be used for post op assessment if required.
This is a combined arthroscopic and open patella realignment. The arthroscopic side involves a patellofemoral chondroplasty, removal of significant plica and a lateral retinacular release. The open component is via a lateral parapatellar incision, an anteromedial medialisation patella tubercule transfer fixed with interfragmentory screws.
Medial hamstring patellofemoral ligament reconstruction For adolescence, multi directional instability and under corrected surgical failures.
For patella alta Lateral patellofemoral tenodesis For over corrected medial subluxation.
For patellofemoral arthritis in a patient with well aligned extensor mechanism.
For example ACL, PCL reconstructions, closing wedge osteotomy of the patella and opening wedge osteotomy of the lateral femoral condyle and patella arthroplasty.
50% have operable lesions and many are predisposed to their dislocation due to malalignment, so my routine there is an x-ray, CT assessment and MRI.
Retrospective review of the consecutive series from 2000 to present using this series to present results but also to highlight complications and failures.
Personal experience of this investigative technique and the surgical principles emanating from that have been used reliably for the last twelve years to produce predictable outcomes in patellofemoral malalignment.
