It is a pleasure to provide perspective on this practical, well-written article by the Orthopaedic Group at the Children’s Hospital Colorado.
Intra-articular injections may not be thought of as particularly innovative, but the application described in this article represents a way of safely delivering local anesthetic following an injury that is often coupled with neurologic challenges in children. Many orthopaedic surgeons have wished for a safe way to provide local analgesia after the treatment of a supracondylar humeral fracture but are concerned with the difficulty of postoperatively monitoring neurologic status. This concern arises because the reduction or the pinning itself can cause neurologic damage1,2. We also worry about the ability to monitor forearm compartment function postoperatively in these children2. Therefore, local anesthetic around the fracture site has not been widely adopted for fear that the agent will interfere with the monitoring of neurologic function. What the authors found, however, is that the elbow joint is a nearby compartment that can serve as a contained repository for the local anesthetic. Injection into the joint can effectively diminish the pain while minimally affecting neurologic monitoring postoperatively.
The authors include an arthrogram for a patient with a Type-II supracondylar fracture illustrating the distended joint capsule surrounding the fracture anteriorly and posteriorly. They propose that the proximity of the joint to the fracture allows pain to be effectively lessened following an intra-articular injection. They administered a dose of 4 mL of local anesthetic for children four to seven years old and 5 mL for children eight to twelve years old. The anesthetic is delivered via a posterolateral approach, with use of blood in the aspirate as a confirmation that the injection is in the joint. The anesthetics used in this study were 0.25% bupivacaine or 0.20% ropivacaine. Bupivacaine is a traditional long-acting amide anesthetic. Ropivacaine is a newer local anesthetic that has been reported to have decreased toxicity compared with bupivacaine. The authors state that, in various other studies ranging from adult joint procedures to tonsillectomies, ropivacaine has been variously reported to have equal efficacy as compared with bupivacaine in some studies and to have higher efficacy in others. Some of the differences are attributable to variations in concentration, as in this study.
The authors showed a modest but significant benefit from the local injection in almost all parameters studied. The patients who were managed with bupivacaine required significantly lower total opioid immediately postoperatively, less narcotic injection, a longer mean time to the first opioid, and less pain as reported by parents or as recorded on the Faces Pain Scale-Revised. Not all parameters showed significance, but almost all showed an improved mean difference in the bupivacaine group as compared with the control groups. Most parameters showed an improvement in the bupivacaine group as compared with the ropivacaine cohorts as well. This finding is somewhat unexpected but may represent the effect of a lower concentration of the ropivacaine.
Interestingly, although “confirmed neurologic injury” was an exclusion criterion for the study, 5% to 10% of the patients had a postoperative neurologic deficit. These findings may represent incomplete detection of preoperative injury, the occurrence of an operative injury, or diffusion of the anesthetic. The fact that even the control group had a 7% rate of neurologic injury suggests that the injuries may be mostly the result of the former two factors. The authors do not elaborate on these possibilities or their implications, and more information would be desirable on this point.
A recent concern also involves the use of intra-articular local anesthetic injection in joints, which poses a risk of chondrolysis. This complication has been reported in association with the use of continuous intra-articular infusions. However, it has not been reported in association with single-dose intra-articular injections. The authors did not note any instances of chondrolysis after their single injection, and it appears to be safe in view of all evidence to date.
It should be noted that epinephrine was not included in the injected mixture, although it is sometimes used to prolong the effect of a local anesthetic. In a supracondylar fracture, use of a vasoconstrictor could increase the risk of vascular compromise.
Methodologically, this Level-I prospective randomized study demonstrated beautiful clinical science applied to a clinically relevant concept. I had not used this technique in the care of patients but certainly intend to give it a try now. In addition, reports from other centers will be useful, both to see if the benefit found by the originators is replicated in the hands of others as well as to monitor for any complications associated with this technique. I think that this is an important article and recommend it to all who treat pediatric elbow fractures.