Comparing the Intensity of Pain and Incidence of Flare Reaction Following Trigger Finger Injections Using Betamethasone and Methylprednisolone: A Double-Blinded, Randomized Controlled Trial.

BACKGROUND: Considerable evidence supports corticosteroid injection as an effective treatment for trigger finger. One common side effect, the flare reaction, is a well-documented phenomenon of increased pain following steroid injections. Its incidence and intensity may be related to steroid composition. The purpose of this study was to determine whether betamethasone and methylprednisolone injections for trigger fingers have differing intensity of pain or incidence flare reaction. METHODS: Patients with symptomatic trigger finger were recruited during their hand surgery visits. Patients were randomized into 2 treatment groups: betamethasone (40 mg) and methylprednisolone (6 mg) mixed with lidocaine 1%. Treatment group assignment was blinded to the patients and investigators. Visual analog scale pain measurements were taken prior to injection, 5 minutes postinjection, and daily thereafter for 7 days. RESULTS: Sixty-four patients were randomized into the 2 treatment groups. Patients in the betamethasone group reported slightly higher baseline pain compared with the methylprednisolone group, but lower pain on day 1. None of the following days showed a statistically significant difference. CONCLUSIONS: The incidence of flare and severe flare reactions of betamethasone injections for trigger finger management was roughly double that of methylprednisolone, but this difference was not statistically significant. Further studies are required to evaluate the relative course of nonflare postinjection pain for different corticosteroid injections for trigger finger injections.

Normal Values of the Second Interosseous Pinch: A Measurement of Pure Ulnar-Innervated Intrinsic Muscles of the Hand.

PURPOSE: The second palmar interosseous muscle is innervated solely by the ulnar nerve, and second palmar interosseous pinch (2IP) strength may be a good indicator of ulnar nerve motor function. The goal of this study was to describe the 2IP test and establish its normative values, stratified by age, sex, and dominance. METHODS: Volunteers were recruited to participate in this study at various community locations. Patients over the age of 18 years were eligible for this study. Demographic information on all subjects was collected. The volunteers were asked to pinch a hydraulic pinch gauge between the index and middle finger proximal phalanges with the proximal and distal interphalangeal joints flexed and without recruiting the thumb. Three 2IP measurements were taken for each hand. Descriptive statistics and analysis of covariance were performed to determine the effect of age, sex, dominance, and side on 2IP. We analyzed the 2IP strength using the 2IP test across 3 trials to determine whether it was affected by repeated testing. RESULTS: Two hundred thirty-eight patients met the inclusion criteria (45 ± 21 years, 55% women, 87% right-hand dominant). There was no statistically significant difference between dominant and nondominant hands or among the 3 trials. There was a statistically significant correlation between age and 2IP strength ranging between 0.32 and 0.44 kg. Age and sex showed a statistically significant association with 2IP strength, with patients of older age and women having weaker 2IP. CONCLUSIONS: We determined normative values for 2IP strength using a sample from a normal population. More studies are needed to validate these results. CLINICAL RELEVANCE: Second interosseous pinch strength may be a useful tool to assess ulnar nerve function.