Objectives: Studies have shown that osteoarthritis [OA] is associated with
hyperalgesia and weakness in muscles resulting in muscle strain, poor posit
ioning, and inappropriate muscle use. Hyperalgesia and indirect injuries re
sulting from forces generated within the musculoskeletal structures during
activity may result in the formation of trigger points [TrPs]. The purpose
of this study was to compare the occurrence of TrPs in healthy controls and
patients with OA of the lower limbs.
Methods: Both lower limbs of fourteen OA patients and an equal number of ag
e and sex matched healthy controls were palpated for the presence of TrPs b
y examining the local twitch reaction, taut bands, nodules, and the pattern
of pain radiation and pain referral.
Results: Significantly greater numbers of latent TrPs in Muscles acting on
the hip joint were present in the OA patients with OA secondary to trauma [
N = 9], as compared to the controls without any history of trauma [N = 9] [
P < 0.05]. Increased TrPs were found in muscles acting on the knee joint in
knee OA as compared to hip OA [P=0.016]. The total number of TrPs in OA pa
tients correlated with the radiological scores of OA [Spearman's R = 0.57,
P = 0.041. The pain evoked by pressure to the TrPs in OA patients was assoc
iated with a significantly larger radiation and referral as compared to the
control subjects [P < 0.05].
Conclusion: The large number of TrPs in secondary [traumatic] OA patients m
ay be due to hyperalgesia resulting from the chronic nociceptive inputs fro
m the sensitized joint nociceptors and central sensitization. The treatment
or elimination of TrPs may play an important role in pain relief of chroni
c OA of lower limbs. (C) 2001 by The Haworth Press, Inc. All rights reserve
d.