Calcific Tendinitis of the Patellar Tendon with MRI Correlations
Author(s): Nicholas Newcomb BS, Bhargav Venkatraghavan BS, Paras Sahani BS, Eric Lin BA, Heather Yerdon BS, Piers Barry MD
Background: Calcific tendinitis is a predominantly cell mediated disease that has been well documented in multiple areas of the body, but very rarely in the patellar tendon. This study presents an unusual case of severe patellar calcific tendinitis initially diagnosed as mucoid degeneration and partial patellar tendon tear after a sports injury. Three modalities of diagnostic imaging were unable to identify calcific deposition which was only discoverable intra-operatively. We describe this unusual presentation and optimal imaging sequences for diagnosis.
Case Report: A 51-year-old male presented three weeks after injuring his left knee playing tennis. The patient lunged forward with his left foot to hit a ball when he felt a sudden sharp pulling sensation at his anterior knee over the patellar tendon. This pain was most pronounced with weight-bearing activities and did not improve over the next month. Left knee radiographs were unremarkable; MRI and ultrasound images demonstrated diffuse patellar tendon partial thickness interstitial tearing and what appeared to be mucoid degeneration. None of the standard imaging modalities identified calcification. Surgical exploration of the patellar tendon revealed a large pocket of classic calcific deposition under pressure which was evacuated prior to tendon repair. The patient had rapid resolution of his pain and was full weight bearing at two weeks post-operation.
Conclusion: Calcific tendinitis of the patellar tendon is an unusual condition that can present diagnostic difficulty. Commonly used imaging modalities and protocols may be insufficient in diagnosing calcification. If tendon calcification is suspected, consideration may be given to the use of gradient-echo sequences as a part of MRI imaging for definitive diagnosis and treatment optimization.