ROLE OF DYNAMIC MRI IN THE ASSESSMENT OF PATELLAR TRACKING – A NEW METHOD USING ACTIVE RESISTED QUADRICEPS CONTRACTION.

Abstract

The diagnosis and subsequent treatment of patients with “Anterior Knee Pain” remains a challenge and an enigma at times.

The 4 main parameters, which need to be assessed, are:

1. Bony anatomy of the PFJ

2. Cartilage structure within the PFJ

3. Tracking of the patella with active knee extension

4. Structure of the soft tissues in the extensor mechanism

While plain radiographs, CT scans and static MRI sans and arthroscopic assessments highlight some of the parameters none of them are comprehensive. The type of MRI scanning used in this study assesses all 4 parameters. The equipment required for resisted quadriceps contraction is inexpensive and readily available.

Material and Methods: 70 patients had dynamic MRI scans done over a period of 2 years. The study consisted of 3 parts:

1. Radiological diagnosis and grading of subluxation if present.

2. Clinical scoring of 26 patients who returned the questionnaires. Oxford, Lysholm and Tegner scores were used and correlated with the radiological scores.

3. Development of a Treatment Algorithm based o the scan results.

Conclusion: The Tibial Tubercle to Trochlear Groove Distance” (TTD) appears to be the single most significant parameter determining patellar tracking. Objective radiological assessment is possible under physiological loading, to differentiate tilt, subluxation and chondromalacia. We have proposed an algorithm for the surgical and non-surgical treatment of anterior knee pain. The pain scores did not show a significant correlation with the grading of subluxation.