This article is more than 5 years old. Information may no longer be current.
The Diagnostic Utility of Midcarpal Anesthetic Injection in the Evaluation of Chronic Wrist Pain
Click Here to Manage Email Alerts
ABSTRACT
The evaluation of chronic wrist pain can be a diagnostic dilemma. Lidocaine injections combined with corticosteroids often are used for therapeutic and diagnostic purposes. This study determined whether a midcarpal injection of lidocaine could serve as a diagnostic tool in patients with chronic wrist pain. Specifically, the relationship of pain relief from the injection and improvement of grip strength were compared to intracarpal pathology as confirmed by wrist arthroscopy.
Forty-five patients with chronic wrist pain underwent a midcarpal injection of lidocaine with or without corticosteroids. Improvement of pain and improvement of grip strength were determined. Each patient subsequently underwent a radiocarpal and midcarpal arthroscopy, and the pathologic findings of arthroscopy were compared to the improvement of pain and grip strength. These data were compared to a cohort of six volunteers without history of wrist pain or trauma who underwent midcarpal injection of lidocaine. Statistical analysis was performed using Receiver-Operator-Characteristic analysis.
The average age of patients with chronic pain was 30.3 years, with an average of 9.8 months of wrist pain. The ultimate diagnoses included carpal dissociative instability (n=35), nondissociative instability (n=2), complex instability of the carpus (n=7), extensor carpi ulnaris tendinitis (n=3), and deQuervain’s tenosynovitis (n=1). After lidocaine injection, the normal cohort had a mean loss of 2 kg (25.3%) (P=.02) in grip strength whereas the experimental cohort had a mean improvement in grip strength of 5.73 kg (34.4%). Improvement of pain after injection did not correlate with pathologic arthroscopic findings (P=.92). Improvement in grip strength after midcarpal lidocaine injection of 6 kg or 28% had a 73% sensitivity and 70% specificity (P=.02) of having intracarpal pathology at arthroscopy. Of the chronic wrist pain patients, only 4 had a normal arthroscopy, and the remainder had at least 1 area of significant pathology attributing to their pain.
A midcarpal injection of lidocaine serves as an effective diagnostic tool in the evaluation of patients with chronic wrist pain. A 28% improvement of grip with or without pain relief is highly correlated with intracarpal pathology.