Premium
Preponderance of sensory versus sympathetic nerve fibers and increased cellularity in the infrapatellar fat pad in anterior knee pain patients after primary arthroplasty
Author(s) -
Lehner Birgit,
Koeck Franz X.,
Capellino Silvia,
Schubert Thomas E. O.,
Hofbauer Raphael,
Straub Rainer H.
Publication year - 2008
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.20498
Subject(s) - infrapatellar fat pad , medicine , osteoarthritis , sensory nerve , sensory system , fat pad , nerve fiber , adipose tissue , anatomy , endocrinology , pathology , neuroscience , biology , alternative medicine
Sensory nerve fibers transmit pain perception and secrete pro‐inflammatory substance P (SP). Sympathetic nerve fibers secrete anti‐inflammatory norepinephrine and endogenous opioids, which inhibit pain perception in a bidirectional crosstalk with sensory fibers. In patients with anterior knee pain after primary arthroplasty of the knee (AKP), this study investigated in parallel the innervation of the infrapatellar fat pad by sensory and sympathetic nerve fibers. A total of 32 patients with osteoarthritis (OA) of the knee ( n = 10), AKP after primary knee joint replacement ( n = 7), and OA of the hip ( n = 15) were included. Sensory nerve fibers were semiquantitatively detected by immunohistochemistry against SP, and sympathetic nerve fibers were stained with an antibody against tyrosine hydroxylase. Cellular density of the tissue was investigated by counting cell nuclei. The density of sympathetic nerve fibers in the fat tissue was similar in knee OA as compared to AKP. In the fat tissue, density of sensory substance P–positive nerve fibers was higher in AKP than in knee OA, which was not observed in the fibrosis capsule of the fat pad. The preponderance of sensory over sympathetic nerve fibers was accompanied by an increased cellular density in fat tissue in patients with AKP compared to knee OA. A positive correlation existed between cellularity and sensory nerve fiber density in fat tissue. This study revealed a preponderance of sensory over sympathetic innervation in the infrapatellar fat pad in AKP after primary arthroplasty of the knee, which possibly leads to aggravation and continuation of AKP and local inflammation. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:342–350, 2008