A new anterior inferior coronal patellar plica.

Purpose: To date, four synovial plicae are classically described in the knee. We report a previously undescribed new inferior patellar plica, named "bib-like plica" (BLP, referring to its morphology) related to specific symptoms of atypical recurrent anterior knee pain in the presence of a locked or pseudo-locked knee. We describe this anatomical structure, and assess its clinical relevance in daily practice in terms of clinical pattern and long-term follow-up outcome after arthroscopic excision.

Methods: We retrospectively reviewed prospectively collected data on 1033 arthroscopic procedures, selecting patients in whom a knee arthroscopy was indicated following recurrent painful episodes of locking or pseudo-locking not explained by traditional imaging or helped by conservative treatment. Visual Analog Scale (VAS), Lysholm knee score, a physical exam and a satisfaction interview were used to evaluate the clinical status at the latest follow-up.

Results: We report 12 patients (8 males, 4 females; mean age 34.2 years) in whom a BLP had been identified at arthroscopy. At a mean follow-up of 13.4 years from its excision, the mean VAS and Lysholm knee score were 9.8 and 100 respectively. In all instances, selective removal of the BLP restored a complete painless functional range of motion documented within 2 months, and confirmed at the latest follow-up. No patient reported locking recurrence or pain, or underwent further surgery, and all were satisfied.

Conclusions: The BLP, detected in about 1% of knee arthroscopies in our setting, is strongly associated with a recurrent painful locking knee. Arthroscopic removal produces resolution of symptoms.