SUMMARY Trigger Finger (trigger thumb when involving the thumb) is the inhibition of smooth tendon gliding due to mechanical impingement at the level of the A1 pulley that causes progressive pain, clicking, catching, and locking of the digit. Diagnosis is made by physical examination with presence of active triggering and tenderness at the A1 pulley. Treatment consists of splinting, anti-inflammatory medications, steroid injections, and surgical release. Epidemiology Incidence 2-3% of general population 10% of diabetic population Demographics more common in diabetics more common in females older than 50 Anatomic location ring and long fingers are most commonly involved in adults Risk factors diabetes Etiology Pathophysiology mechanism caused by stenosing tenosynovitis at the A1 pulley pathophysiology fibrocartilaginous metaplasia of tendon and/or pulley proliferation of chondrocytes increased type III collagen chronic hyperglycemia creates collagen cross-links login to view 1 more bullet pathoanatomy occasional pathologic nodule of the flexor digitorum profundus tendon flexor digitorum superficialis often unaffected trigger thumb may have a fourth pulley (variable annular pulley) causing stenosis in up to 75% of patients Associated conditions orthopaedic conditions rheumatoid arthritis calcific tendinitis septic tenosynovitis carpal tunnel syndrome login to view 1 more bullet congenital trigger thumb medical conditions and comorbidities diabetes login to view 1 more bullet amyloidosis hypothyroidism sarcoidosis gout pseudogout Anatomy Muscles flexor digitorum profundus may develop pathologic nodule that inhibits smooth tendon gliding through A1 pulley flexor digitorum superficialis often unaffected one slip may be released to allow for smooth tendon gliding Ligaments first annular ligament (A1 pulley) overlies the MP joints Classification Green Classification Grade I Palm pain and tenderness at A-1 pulley Grade II Catching of digit Grade III Locking of digit, passively correctable Grade IV Fixed, locked digit Presentation Symptoms common symptoms usually progressive pain at the level of the A1 pulley clicking catching finger becoming "locked" in flexed position at the proximal interphalangeal (PIP) joint may have referred pain to dorsal MCP/PIP region Physical exam palpation tenderness at level of A1 pulley palpable nodule of the flexor tendon motion triggering with digit flexion and extension fixed flexion of PIP joint provocative test flexion and extension of the digit may reproduce symptoms Imaging Radiographs indications radiographs not required in diagnosis or treatment Differential Lumbrical plus finger differentiated by paradoxical extension while trying to flex the digit Joint contracture differentiated by history of trauma and inability to passively extend the digit Pyogenic flexor tenosynovitis differentiated by signs of infection, including possible elevated inflammatory markers, and positive Kanavel signs Diagnosis Clinical diagnosis made by history and physical exam Treatment Nonoperative splinting, activity modification, NSAIDs indications login to view 1 more bullet outcomes login to view 1 more bullet corticosteroid injection indications login to view 1 more bullet outcomes login to view 4 more bullets Operative percutaneous release of A1 pulley indications login to view 1 more bullet outcomes login to view 4 more bullets open surgical debridement and release of the A1 pulley indications login to view 3 more bullets outcomes login to view 3 more bullets release of A1 pulley and 1 slip of FDS (usually ulnar slip) indications login to view 7 more bullets outcomes login to view 1 more bullet Techniques Splinting, activity modification, NSAIDs technique immobilization either the metacarpophalangeal (MCP) joint or distal interphalangeal joint only proximal interphalangeal joint remains unrestricted Corticosteroid injection technique give 1 to 3 injections in or just superficial to flexor tendon sheath can be combined with percutaneous A1 pulley release complications fat atrophy tendon rupture subcutaneous fat atrophy transient hyperglycemia login to view 1 more bullet Percutaneous release of A1 pulley technique typically 18- to 19-gauge needle bevel parallel to tendon movement of digit confirms placement into tendon needle withdrawn until out of tendon then advanced to cut ligament release confirmed by attempt to reproduce symptoms can be combined with corticosteroid injection complications transient inflammation hematoma formation persistent pain and tenderness stiffness infection damage to neurovascular bundle Open surgical debridement and release of A1 pulley approach longitudinal, transverse, or oblique incision technique local anesthetic allows intraoperative assessment of triggering to confirm an adequate release slip of FDS released if persistent triggering in addition to A-1 pulley, may also need to release login to view 3 more bullets postoperative login to view 2 more bullets complications tendon bowstringing damage to the digital neurovascular bundle stiffness Release of A1 pulley and 1 slip of FDS approach longitudinal, transverse, or oblique incision technique local anesthetic allows intraoperative assessment of triggering to confirm an adequate release slip of FDS detached from insertion and removed as far as the palm login to view 1 more bullet carefully debride to ensure it will not catch on the proximal pulley Complications Radial digital nerve injury risk factors trigger thumb release due to superficial location and oblique orientation treatment may require digital nerve and artery repair Bowstringing risk factors damage to the A2 or A4 pulley treatment may require pulley reconstruction Wound dehiscence Scar tenderness Stiffness Tendon scoring (percutaneous technique) Prognosis Natural history of disease progressive symptoms beginning with pain over A1 pulley and progressing to a fixed flexed digit Prognostic variables favorable non-diabetic Survival with treatment relief with injections alone is achieved in up to 90% of non-diabetics relief with surgery is achieved in >90% of all patients