Summary Flexor carpi radialis tendinitis is a condition characterized by pain over the volar radial wrist caused by inflammation of the FCR tendon sheath. Diagnosis is made clinically with pain over the FCR tendon that worsens with resisted wrist flexion. Treatment usually involves immobilization, NSAIDs and injections. In rare refractory cases operative release of the FCR tendon sheath may be indicated. Epidemiology Incidence rare < 1 per 100,000 annually Risk factors repetitive wrist flexion golfers and racquet sports manual labor Etiology Pathoanatomy primary stenosing tenosynovitis within the fibroosseous tunnel (see Anatomy) secondary tendinitis associated with scaphoid fracture scaphoid cysts distal radius fracture scaphoid-trapezium-trapezoid joint arthritis thumb CMC joint arthritis Anatomy Flexor carpi radialis musculotendinous unit FCR muscle bipennate FCR tendon enveloped by sheath from musculotendinous origin to trapezium login to view 1 more bullet enters fibroosseous tunnel at the proximal border of the trapezium login to view 14 more bullets insertion login to view 3 more bullets Presentation Symptoms volar radial aspect of the wrist Physical exam tenderness over volar radial forearm along FCR tendon at distal wrist flexion crease provocative test resisted wrist flexion triggers pain resisted radial wrist deviation triggers pain Imaging Radiographs findings in primary tendinitis, radiographs are unremarkable in secondary tendinitis, the following may be present login to view 3 more bullets MRI views best seen on T2 findings increased signal around FCR sheath on T2 image may find associated conditions in secondary tendinitis login to view 2 more bullets Studies Diagnostic injection injection of local anesthetic along FCR sheath relieves symptoms Differentials Thumb CMC arthritis Scaphoid cyst Ganglion cyst De Quervain's tenosynovitis Carpal tunnel syndrome Diagnosis Clinical and MRI diagnosis is made with careful history and physical examination and can be confirmed with MRI studies Treatment Nonoperative immobilization, NSAIDS, steroid injection indications login to view 1 more bullet technique login to view 1 more bullet outcomes login to view 2 more bullets Operative surgical release of FCR tendon sheath indications login to view 1 more bullet TechniqueS Surgical release of FCR tendon sheath approach volar longitudinal incision starting proximal to the wrist crease, extending over proximal thenar eminence login to view 4 more bullets technique elevate and reflect thenar muscles radially expose FCR sheath open FCR sheath proximally in the distal forearm, and extend to the trapezial crest at the trapezial crest, the tendon enters the FCR tunnel at this point, incise the sheath along the ulnar margin, taking care not to injure the tendon mobilize tendon from trapezoidal groove (releasing trapezial insertion) Complications Complications of disease FCR attrition and rupture Complications of surgical release cutaneous nerve injury palmar cutaneous branch of median nerve lateral antebrachial cutaneous nerve superficial sensory radial nerve injury to deep palmar arch injury to FPL tendon (lies superficial to FCR tendon) injury to FCR tendon within the tunnel decompression is easy proximal to the tunnel (incision of FCR sheath) within FCR fibroosseous tunnel, take care to avoid cutting FCR tendon Prognosis Poor prognostic variables history of overuse worker's compensation failure to respond to local injection long duration of symptoms