The fate of patellar tendon and infrapatellar fat pad after arthroscopy via central portal.

Central patellar (CP) portal is an accessory portal in arthroscopic knee surgery, which generally is considered to be safe. In this cross sectional study, we aimed to delineate the clinical and radiological outcome of patellar tendon (PT) and Hoffa's fat pad after the use of this approach. From our hospital records, patients who underwent arthroscopy via CP portal were identified and were invited for the study. There were16 men and 4 women with a mean age of 32 years. Mean follow-up time was 28 months. Meniscectomy had been performed for irreparable bucket-handle type medial meniscal tears in all patients. At the latest follow-up, no patients had anterior knee pain and physical examination was normal. Mean PT thickness of operated knees measured with Ultrasonography was 5.63+/-1.56, while it was 3.76+/-0.46 mm in contralateral knees and the difference was significant. Contour irregularity of PT and focal hypoechoic areas were found in 17 patients, two of which also had hyperechogenic calcification focuses. Abnormal signal intensity of PT was also found in 17 patients with Magnetic Resonance Imaging (MRI). Eleven of these had decreased signal intensity within the tendon which was interpreted as fibrosis. In six patients, increased signal intensity, radiologically similar to chronic tendinitis, was detected. Four patients had decreased signal intensity in the Hoffa's fat pad. Local fibrous tissues in patellar tendon might cause weakness in the tendon. This study showed that although CP portal did not cause any clinical problems in a low demand group of patients, it leads to a significant radiological sequela in the tendon, biomechanical significance of which needs to be clarified.