Ulnar hammer syndrome: a systematic review of the literature. 
Ulnar hammer syndrome is an uncommon form of arterial insufficiency.  Many treatments have been described, and debate continues about the best option.  The goal of this systematic review was to determine whether ulnar hammer syndrome has an occupational association, to identify the most reliable diagnostic test, and to determine the best treatment modality.  A comprehensive literature search was conducted using the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, MEDLINE, CINAHL, and EMBASE.  Data from articles meeting inclusion criteria were collected in duplicate.  Methodological quality of studies was assessed using the Methodological Index for Nonrandomized Studies scale.  Thirty studies were included in the systematic review.  No randomized controlled trials were identified.  There is low-quality evidence suggestive of an association between exposure to repetitive hand trauma and vibration and ulnar hammer syndrome.  Various diagnostic investigations were used, but few were compared, making it difficult to determine the most reliable diagnostic test.  Numerous nonoperative and operative treatments were reported.  With nonoperative treatment, 12 percent had complete resolution and 70 percent had partial resolution of their symptoms.  Of patients treated operatively, 42.5 percent had complete resolution and 42.5 percent had partial resolution of their symptoms.  The heterogeneity in study design and outcome measures limits definitive conclusions about occupational association, best diagnostic test, and treatment for ulnar hammer syndrome.  However, there is low-quality evidence that suggests that most patients with ulnar hammer syndrome will have partial relief of symptoms with nonoperative treatment, and operative treatment results in complete or partial resolution of symptoms in the majority of cases.  Therapeutic, IV.