What Are the Long-term Effects of Repeated Joint Injections for Chronic Pain?
What Are the Long-term Effects of Repeated Joint Injections for Chronic Pain?
Intra-articular injections are routinely performed in physicians' offices, typically with a mix of steroid and anesthetic medications. Recent studies, however, have shown potential chondrocyte toxicity when local anesthetics are used for intra-articular purposes.
Chu CR, Coyle CH, Chu CT, et al
J Bone Joint Surg Am. 2010;92:599-608
Chu and colleagues at the University of Pittsburgh performed an in vivo study in 48 rats to compare the effects of intra-articular injections of preservative-free 0.5% bupivacaine with those of 0.9% normal saline solution (negative control) and 0.6 mg/mL monoiodoacetate (positive control).
Animals received injections of the negative control solution into 1 stifle joint (analogous to the human knee joint) and either bupivacaine or monoiodoacetate in the contralateral joint. The joints were evaluated at 1 week, 4 weeks, 12 weeks, and 6 months on the basis of anatomical examination, histologic findings, surface chondrocyte viability, and chondrocyte cell density.
At 6 months, chondrocyte cell density decreased by up to 50% in the bupivacaine group compared with the saline group (P ≤ .01). However, no significant differences were noted on gross and microscopic examination, histologic appearance, or surface chondrocyte viability.
In the monoiodoacetate group, up to 87% of superficial chondrocytes were lost after the first week. Furthermore, 60% of rats in the monoiodoacetate group had significant cartilage erosion, with full thickness chondrocyte loss and fibrosis at 6 months.
This study demonstrates in vivo the potential chondrotoxicity associated with intra-articular bupivacaine use. Although these findings seem to be subtle and are probably subclinical after just 1 injection, they indicate the possible spectrum of iatrogenic injury that may be caused by repeated injections of local anesthetics commonly used to treat articular pain. Current literature would suggest that physicians exercise caution when using high-dose, intra-articular local anesthetics, particularly when given with a corticosteroid. Future comparative studies of arthritic knee joints and different anesthetics, with and without the use of steroids, in repeated injections would help to further delineate the clinical ramifications of such use.
Abstract
Introduction
Intra-articular injections are routinely performed in physicians' offices, typically with a mix of steroid and anesthetic medications. Recent studies, however, have shown potential chondrocyte toxicity when local anesthetics are used for intra-articular purposes.
In Vivo Effects of A Single Intra-articular Injection of 0.5% Bupivacaine on Articular Cartilage
Chu CR, Coyle CH, Chu CT, et al
J Bone Joint Surg Am. 2010;92:599-608
Summary
Chu and colleagues at the University of Pittsburgh performed an in vivo study in 48 rats to compare the effects of intra-articular injections of preservative-free 0.5% bupivacaine with those of 0.9% normal saline solution (negative control) and 0.6 mg/mL monoiodoacetate (positive control).
Animals received injections of the negative control solution into 1 stifle joint (analogous to the human knee joint) and either bupivacaine or monoiodoacetate in the contralateral joint. The joints were evaluated at 1 week, 4 weeks, 12 weeks, and 6 months on the basis of anatomical examination, histologic findings, surface chondrocyte viability, and chondrocyte cell density.
At 6 months, chondrocyte cell density decreased by up to 50% in the bupivacaine group compared with the saline group (P ≤ .01). However, no significant differences were noted on gross and microscopic examination, histologic appearance, or surface chondrocyte viability.
In the monoiodoacetate group, up to 87% of superficial chondrocytes were lost after the first week. Furthermore, 60% of rats in the monoiodoacetate group had significant cartilage erosion, with full thickness chondrocyte loss and fibrosis at 6 months.
Viewpoint
This study demonstrates in vivo the potential chondrotoxicity associated with intra-articular bupivacaine use. Although these findings seem to be subtle and are probably subclinical after just 1 injection, they indicate the possible spectrum of iatrogenic injury that may be caused by repeated injections of local anesthetics commonly used to treat articular pain. Current literature would suggest that physicians exercise caution when using high-dose, intra-articular local anesthetics, particularly when given with a corticosteroid. Future comparative studies of arthritic knee joints and different anesthetics, with and without the use of steroids, in repeated injections would help to further delineate the clinical ramifications of such use.
Abstract
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