title: Use of anatomic measurement to guide injection of botulinum toxin for the management of chronic lateral epicondylitis: a randomized controlled trial.
abstract: BACKGROUND
  When using botulinum toxin for the management of lateral epicondylitis, injection at a fixed distance from an anatomic landmark could result in inadequate paralysis of the intended muscle. We assessed the effectiveness of injection of botulinum toxin using precise anatomic measurement in individual patients.
  
  
  METHODS
  In this randomized placebo-controlled trial, 48 patients with chronic refractory lateral epicondylitis were randomly assigned to receive a single injection of either botulinum toxin (60 units) or placebo (normal saline). The site of injection was chosen as a distance one-third the length of the forearm from the tip of the lateral epicondyle on the course of the posterior interosseus nerve. The primary outcome measure was intensity of pain at rest, measured with the use of a 100-mm visual analogue scale, at baseline and at 4, 8 and 16 weeks after injection.
  
  
  RESULTS
  Compared with the placebo group, the group given botulinum toxin had significant reductions in pain at rest during follow-up (decrease at 4 weeks 14.1 mm, 95% confidence interval [CI] 5.8-22.3; at 8 weeks 11.5 mm, 95% CI 2.0-21.0; at 16 weeks 12.6 mm, 95% CI 7.7-17.8; p = 0.01). As for the secondary outcomes, the intensity of pain during maximum pinch decreased in the botulinum toxin group; there was no difference in pain during maximum grip or in grip strength between the two groups. All but one of the patients in the intervention group experienced weakness in the extension of the third and fourth fingers at week 4 that resolved by week 16. No serious adverse events were reported.
  
  
  CONCLUSIONS
  The use of precise anatomic measurement to guide injection of botulinum toxin significantly reduced pain at rest in patients with chronic refractory lateral epicondylitis. However, the transient extensor lag makes this method inappropriate for patients whose job requires finger extension.
authors.affiliation: Departments of Orthopedic Surgery, ImamKhomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
authors.forename: Ramin
authors.initials: R
authors.lastname: Espandar
authors.forename: Pedram
authors.initials: P
authors.lastname: Heidari
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Rasouli
authors.forename: Soheil
authors.initials: S
authors.lastname: Saadat
authors.forename: Mahmood
authors.initials: M
authors.lastname: Farzan
authors.forename: Mohsen
authors.initials: M
authors.lastname: Rostami
authors.forename: Shideh
authors.initials: S
authors.lastname: Yazdanian
authors.forename: S M Javad
authors.initials: SM
authors.lastname: Mortazavi
mesh_terms: D000328:Adult; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D002908:Chronic Disease; D005260:Female; D005542:Forearm / Q000033:anatomy & histology; D018737:Hand Strength; D006801:Humans; D007273:Injections, Intramuscular / Q000379:methods*; D008297:Male; D018908:Muscle Weakness; D018482:Muscle, Skeletal / Q000294:innervation; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D010147:Pain Measurement; D010291:Paresis / Q000209:etiology; D013716:Tennis Elbow / Q000188:drug therapy*
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A