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Flexor Tenosynovitis

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Authors

Connor Farrell, DO
Resident Physician
Long Beach Memorial Medical Center

Shelby Armstrong-Kager, DO
Resident Physician
Long Beach Memorial Medical Center

Haley Oosterhouse, MD
Resident Physician
Long Beach Memorial Medical Center

Summary

  • Flexor tenosynovitis (FTS) is characterized by inflammation of a tendon and its respective tendon sheath
  • Causes including idiopathic, inflammatory, or, most concerningly, infectious etiologies.
  • Ultrasound can been utilized to aid in diagnosis and assess severity of flexor tenosynovitis
  • On ultrasound, FTS is characterized by thickening of the synovial flexor tendon sheath and hypoechoic/anechoic fluid surrounding the tendon
Anatomy of flexor tendons and sheath.
Infectious thumb Flexor Tenosynovitis in long axis.
Infectious thumb Flexor Tenosynovitis in short axis.
Flexor Tenosynovitis with Dr Karkucak
Good sonographic video of FTS

Introduction

  • Stenosing (Idiopathic) Flexor Tenosynovitis
    • Also known as ‘Trigger Finger’
    • Characterized by a catching sensation and inability to smoothly flex or extend one or multiple fingers, most often at the A1 pulley[1]Bianchi S, Gitto S, Draghi F. Ultrasound features of trigger finger: Review of the literature. J Ultrasound Med. 2019;38(12):3141-3154.
    • May result in locking of the finger or a painful nodule over the palmar metacarpophalangeal joint (MCP)
    • The majority of cases are idiopathic, however, there is an association with repetitive activities or microtrauma, and an increased incidence in patients with diabetes, rheumatoid arthritis, and amyloidosis[2]Makkouk AH, Oetgen ME, Swigart CR, Dodds SD. Trigger finger: etiology, evaluation, and treatment. Curr Rev Musculoskelet Med. 2008;1(2):92-96.
Trigger finger stenosing tenosynovitis
A patient with flexor tenosynovitis (trigger finger) is trying to straighten out all of his fingers, but the middle finger is locked
    • Histologic evidence in patients with trigger finger has shown fibrocartilaginous metaplasia at the innermost layer of the A1 pulley leading to hypertrophy of the pulley and a stenotic fibro-osseous canal that causes tendon entrapment[3]Bianchi S, Gitto S, Draghi F. Ultrasound features of trigger finger: Review of the literature. J Ultrasound Med. 2019;38(12):3141-3154.
    • Treated with conservative management with orthotic bracing, non-steroid anti-inflammatory drugs (NSAIDs), steroid injection or surgical release[4]Kraemer BA, Young VL, Arfken C. Stenosing flexor tenosynovitis. South Med J. 1990;83(7):806-811.
  • Inflammatory Flexor Tenosynovitis
    • Common in rheumatoid arthritis and other rheumatologic conditions
    • Characterized by joint swelling, erythema, joint pains, synovitis, joint deformity, locking, decreased range of motion, and in extreme cases, tendon rupture[5]Ferlic DC. Rheumatoid flexor tenosynovitis and rupture. Hand Clin. 1996;12(3):561-572.
    • Tenosynovitis in rheumatoid arthritis is due to compression and/or invasion of the rheumatoid pannus into the tendon leading to edema, ischemia and necrosis[6]Hmamouchi I, Bahiri R, Srifi N, Aktaou S, Abouqal R, Hajjaj-Hassouni N. A comparison of ultrasound and clinical examination in the detection of flexor tenosynovitis in early arthritis. BMC … Continue reading
    • Flexor tenosynovitis in RA has preference to affect the 2nd and 3rd MCP joints likely due to the greater range of motion of these joints and increased likelihood of erosion and synovitis[7]Gray RG, Gottlieb NL. Hand flexor tenosynovitis in rheumatoid arthritis. Prevalence, distribution, and associated rheumatic features. Arthritis Rheum. 1977;20(4):1003-1008.
    • Ultrasound can help distinguish synovial changes which is helpful for early detection of rheumatoid arthritis[8]Danielsen MA. Ultrasonography for diagnosis, monitoring and treatment of tenosynovitis in patients with rheumatoid arthritis. Dan Med J. 2018;65(3).[9]Backhaus M. Ultrasound and structural changes in inflammatory arthritis: synovitis and tenosynovitis: Synovitis and tenosynovitis. Ann N Y Acad Sci. 2009;1154(1):139-151.
    • Requires treatment of the underlying etiology. Surgical intervention includes flexor tenosynovectomy with possible decompression of the affected nerve and tendon sheath. In serious cases, tendon reconstruction may be indicated[10]Ferlic DC. Rheumatoid flexor tenosynovitis and rupture. Hand Clin. 1996;12(3):561-572.
  • Infectious Flexor Tenosynovitis
    • Infectious flexor tenosynovitis is due to an untreated puncture wound or trauma that leads to infection of, and purulence within, the tendon sheath
    • Kanavel’s Cardinal signs of FTS[11]Padrez K, Bress J, Johnson B, Nagdev A. Bedside ultrasound identification of infectious flexor tenosynovitis in the emergency department. West J Emerg Med. 2015;16(2):260-262.
      • Tenderness over the affected tendon sheath
      • Digit held in flexion
      • Pain with passive extension of the digit
      • Uniform swelling of the digit
Pyogenic flexor tenosynovitis
The right middle finger of this patient with pyogenic flexor tenosynovitis. Exam demonstrates fusiform swelling, digit held in flexion with tenderness to palpation along the flexor tendon sheath and exquisite pain with passive digit extension[12]Kennedy CD, Huang JI, Hanel DP. In brief: Kanavel’s signs and pyogenic flexor tenosynovitis. Clin Orthop Relat Res. 2016;474(1):280-284.
    • Most common organisms that cause infection are Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA), and Streptococcus pyogenes[13]Hyatt BT, Bagg MR. Flexor tenosynovitis. Orthop Clin North Am. 2017;48(2):217-227.
    • Considered a surgical emergency, most require IV antibiotics with irrigation and debridement
    • Sequelae of infectious causes include tendon necrosis and rupture, hand dysfunction, sepsis, and possibly death

Ultrasound Evaluation

  • Patient is seated with their hand resting on a surface and palm facing up with fingers extended
  • Probe: multifrequency linear array transducer
  • Perform a multiplanar scan of the affected joint.
    • At the affected area, place the probe at the flexor crease in the short axis plane and then the long axis plane to visualize the flexor tendons
    • Scan proximal to distal in short axis scans and medial to lateral in long axis scans
  • At the wrist: scan the dorsal, ulnar, and palmar aspects
  • Scan both the palmar and dorsal aspects of the metacarpophalangeal joint (MCP), proximal interphalangeal joint (PIP), and distal interphalangeal joint (DIP)
Wrist US Flexor Tendon in Long Axis Normal
Normal ultrasound of a flexor tendon in long axis.
Normal ultrasound of a flexor tendon in short axis.

Pathology

  • Stenosing Flexor Tenosynovitis (ie, trigger finger)
    • Sonographic features
      • Hypoechoic thickening of the A1 pulley adjacent to the corresponding MCP joint, often associated with hypervascularization[14]Vuillemin V, Guerini H, Bard H, Morvan G. Stenosing tenosynovitis. J Ultrasound. 2012;15(1):20-28.[15]Bianchi S, Gitto S, Draghi F. Ultrasound features of trigger finger: Review of the literature. J Ultrasound Med. 2019;38(12):3141-3154.
    • Other associated findings include:
      • Peritendinous effusion
      • Signs of tendinosis that include loss of normal fibrillar pattern with generalized hypoechoicity, with or without effusion[16]Hodgson RJ, O’Connor PJ, Grainger AJ. Tendon and ligament imaging. Br J Radiol. 2012;85(1016):1157-1172.
Long axis view of stenosing flexor tenosynovitis showing thickened flexor tendon with hypoechoic fluid (arrows) noted anterior to the tendon.[17]Vuillemin V, Guerini H, Bard H, Morvan G. Stenosing tenosynovitis. J Ultrasound. 2012;15(1):20-28.
Short axis view of flexor tenosynovitis showing flexor tendon thickening and surrounding hyperemia (arrowheads) with color doppler.[18]Bianchi S, Gitto S, Draghi F. Ultrasound features of trigger finger: Review of the literature. J Ultrasound Med. 2019;38(12):3141-3154.
  • Inflammatory Flexor Tenosynovitis
    • Sonographic features
      • Abnormal hypoechoic or anechoic material within the tendon sheath
      • Possible doppler signals in two perpendicular planes is consistent with flexor tenosynovitis[19]Hmamouchi I, Bahiri R, Srifi N, Aktaou S, Abouqal R, Hajjaj-Hassouni N. A comparison of ultrasound and clinical examination in the detection of flexor tenosynovitis in early arthritis. BMC … Continue reading[20]Backhaus M. Ultrasound and structural changes in inflammatory arthritis: synovitis and tenosynovitis: Synovitis and tenosynovitis. Ann N Y Acad Sci. 2009;1154(1):139-151.
    • The edema and hyperemia within the tendon sheath is responsible for the anechoic fluid and surrounding doppler signal within the tendon.
    • Necrosis and erosion from rheumatologic processes may contribute to material within the sheath
Long axis view showing probe position and normal tendon.[21]Backhaus M. Ultrasound and structural changes in inflammatory arthritis: synovitis and tenosynovitis: Synovitis and tenosynovitis. Ann N Y Acad Sci. 2009;1154(1):139-151.
Wrist US Inflammatory Flexor Tenosynovitis 2
Long axis view demonstrating tenosynovitis with edema, fluid in the sheath (*) and a thickened flexor tendon (ft)[22]Backhaus M. Ultrasound and structural changes in inflammatory arthritis: synovitis and tenosynovitis: Synovitis and tenosynovitis. Ann N Y Acad Sci. 2009;1154(1):139-151.
  • Infectious/Pyogenic Tenosynovitis
    • Sonographic Features
      • Hypoechoic or anechoic fluid surrounding the flexor tendon inside the sheath with thickening of the tendon sheath.[23]Prunières G, Igeta Y, Hidalgo Díaz JJ, et al. Ultrasound for the diagnosis of pyogenic flexor tenosynovitis. Hand Surg Rehabil. 2018;37(4):243-246.
      • Thickened synovial sheath that has hyperemia on coppler doppler[24]Jardin E, Delord M, Aubry S, Loisel F, Obert L. Usefulness of ultrasound for the diagnosis of pyogenic flexor tenosynovitis: A prospective single-center study of 57 cases. Hand Surg Rehabil. … Continue reading
    • Significant effusion within the tendon sheath can be helpful when diagnosing pyogenic flexor tenosynovitis when clinic findings are nonspecific
Wrist US Infectious Flexor Tenosynovitis Long Axis
Long axis ultrasound of infectious tenosynovitis with hypoechoic fluid surrounding the tendon sheath.[25]Jardin E, Delord M, Aubry S, Loisel F, Obert L. Usefulness of ultrasound for the diagnosis of pyogenic flexor tenosynovitis: A prospective single-center study of 57 cases. Hand Surg Rehabil. … Continue reading
Wrist US Infectious Flexor Tenosynovitis Short Axis
Short axis ultrasound of the same patient with infectious tenosynovitis with hypoechoic fluid surrounding the tendon sheath.[26]Jardin E, Delord M, Aubry S, Loisel F, Obert L. Usefulness of ultrasound for the diagnosis of pyogenic flexor tenosynovitis: A prospective single-center study of 57 cases. Hand Surg Rehabil. … Continue reading
Wrist US Infectious Flexor Tenosynovitis Long Axis Color Doppler
Long axis view of infectious tenosynovitis with hyperemia on color doppler and synovial thickening.[27]Jardin E, Delord M, Aubry S, Loisel F, Obert L. Usefulness of ultrasound for the diagnosis of pyogenic flexor tenosynovitis: A prospective single-center study of 57 cases. Hand Surg Rehabil. … Continue reading
Wrist US Infectious Flexor Tenosynovitis Short Axis Color Doppler
Short axis view of infectious tenosynovitis with hyperemia on color doppler and synovial thickening.[28]Jardin E, Delord M, Aubry S, Loisel F, Obert L. Usefulness of ultrasound for the diagnosis of pyogenic flexor tenosynovitis: A prospective single-center study of 57 cases. Hand Surg Rehabil. … Continue reading

Pearls & Pitfalls

  • Assessment in both short axis and long axis planes assists with visualization of flexor tendon thickness and surrounding fluid and hyperemia
  • Utilization of dynamic movement may improve visualization of the affected tendon and tendon sheath
  • When scanning stenosing flexor tenosynovitis, rotate the transducer to long axis and use the A1 pulley as a landmark for the affected digit
    • Stenosing flexor tenosynovitis most often affects the 4th digit or the thumb
  • In inflammatory flexor tenosynovitis, ultrasound can help distinguish synovial changes which is helpful for early detection of rheumatoid arthritis
    • Flexor tenosynovitis in RA has preference to affect the 2nd and 3rd MCP joints
  • With infectious flexor tenosynovitis, early diagnosis can be difficult since patients rarely present with Kanavel’s classic signs, so ultrasound can be helpful in visualizing changes in the flexor tendon
    • Ultrasound may assist in the diagnosis and treatment of flexor tenosynovitis, however, ultrasound alone (without clinical correlation) is not sufficient enough to differentiate between etiologies of flexor tenosynovitis

References

References[+]