Orthopedics

Getting a Hand-le on Pyogenic Flexor Tenosynovitis

CASE

A 45-year-old, right-hand dominant, diabetic female presents with one day of right index finger swelling and pain. She is two weeks status-post right index and middle finger trigger release. In the ED, she is febrile to 101 degrees Fahrenheit, and her exam is notable for fusiform swelling of the digit which is held in flexion. She has pain with passive ROM and tenderness along the flexor tendon.

 Figure 1. Erythematous, diffusely swollen index finger. Courtesy of  Orthobullets

Figure 1. Erythematous, diffusely swollen index finger. Courtesy of Orthobullets

 Figure 2. Plain radiograph of the hand.

Figure 2. Plain radiograph of the hand.

QUESTION
What is the most sensitive and specific finding to diagnose pyogenic flexor tenosynovitis?

A.      Finger held in flexion.

B.       Pain along the flexor tendon sheath.

C.       Fusiform swelling of the digit.

D.      Pain with passive extension.

Trick question! It's actually none of the above. Read on to find out why.

REVIEW

Flexor tenosynovitis consists of inflammation of the flexor tendon and its synovial sheath. The synovial sheath is comprised of both a visceral layer that adheres to the tendon and an outer parietal layer. Inflammation can lead to accumulation of fluid in this potential space and, when infection is the inciting etiology, the condition is called pyogenic flexor tenosynovitis (PFT).

PFT is a surgical emergency – it can lead to substantial morbidity, such as loss of function, tendon necrosis or rupture, deep space infection, and amputation. The prevalence of PFT is estimated at 2.5 - 9.4% of all hand infections (1, 2).

ANATOMY

 Figure 3. Flexor tendon sheaths of the hand.    Courtesy of  Orthobullets

Figure 3. Flexor tendon sheaths of the hand.
Courtesy of Orthobullets

There are many anatomic variations to the flexor tendon sheath anatomy, but common themes exist.

  • In the fingers, the distal sheaths terminate at the insertion of the FDP (near the DIP joint).
  • In the thumb, the sheath terminates at the insertion of the FPL (near the IP joint).
  • For digits 2-4, the sheaths commonly extend just proximal to the A1 pulley (near the MCP joint).
  • The small finger and thumb sheaths typically communicate with the ulnar and radial bursae, respectively. As a result, infection can spread from the little finger to the thumb, or vice versa, leading to the development of a horseshoe abscess.

PATHOGENESIS

PFT can be caused by three mechanisms:

  •  Direct inoculation (most common)
    • Trauma (associated with skin flora):
      • Staphylococcus aureus is the most common organism
      • IVDU (MRSA)
      • Fresh/salt water (Mycobacterium marinum)
      • Plants (Sporotrichosis)
    • Bite wounds (polymicrobial)
      • Cat/dog (Pasteurella)
      • Human (Eikenella)
  • Contiguous spread from nearby soft tissue structures
    • Examples: felon, septic joint, deep space infection
  • Hematogenous spread
    • Neisseria gonorrhea – consider in sexually active patient with polyarthralgias and/or skin lesions
    • Mycobacteria – rubbery masses over the tendon sheath

RISK FACTORS

In a study of 75 patients with PFT, Pang et al. identified the following risk factors that correlated with worsening clinical outcomes, especially amputation rate and effect on total active motion (3):

  • Age >43
  • Presence of DM, PVD, or renal failure
  • Polymicrobial infection
  • Subcutaneous purulence
  • Digital Ischemia 

Other notable risk factors are immunocompromised and intravenous drug use.

DIFFERENTIAL DIAGNOSIS

In addition to PFT, the differential diagnosis for a red, swollen digit(s) or hand includes felon, herpetic whitlow, cellulitis, abscess, septic arthritis, gout, and pseudogout.

KANAVEL’S SIGNS

Kanavel notably indentified four criteria for diagnosing PFT (4):

  • Finger held in passive flexion
  • Pain with passive extension
  • Tenderness along flexor tendon sheath
  • Fusiform swelling or “sausage digit” 

Although Kanavel’s signs are the hallmark for clinical detection of PFT, no studies have validated their sensitivity and specificity, and there is no consensus among studies regarding which sign is most predictive of PFT (5, 6). It is important to remember that a negative exam does not rule out PFT, so if we cannot rely solely on Kanavel’s signs, what other tools can be used in the ED to assist in early recognition of PFT?

ULTRASOUND

Point-of-care ultrasound is a quick and non-invasive way to help distinguish PFT from other conditions such as cellulitis or abscess, and ultrasound can guide appropriate management (7-9). Ultrasound appears to be sensitive study for detecting PFT (10, 11) and may actually be more sensitive than clinical exam in detecting tenosynovitis (12, 13). Although radiographs are typically ordered to evaluate for bony abnormalities or foreign body, ultrasound has the added benefit of detecting radiolucent foreign bodies.

 Figure 4 .  Water bath technique for ultrasound of the hand.

Figure 4. Water bath technique for ultrasound of the hand.

The water bath technique is a simple and effective way to image structures of the hand:

Step 1: Fill a large basin with warm water.

Step 2: Have the patient submerge their hand in the bath.

Step 3: Float the linear transducer in the water above their hand and direct as needed.

Since the water bath acts as an acoustic medium, the probe does not need to be in direct contact with the hand—and your patients will be grateful if they have any tenderness.

 Figure 5.   Normal flexor tendon anatomy on ultrasound.

Figure 5. Normal flexor tendon anatomy on ultrasound.

Anechoic or hypoechoic fluid within the tendon sheath and thickening of tendons are highly suspicious for pyogenic flexor tenosynovitis in the appropriate clinical context. Compare this with the cobblestone appearance of cellulitis on ultrasound.

 Figure 6. Cellulitis. Note the cobblestone appearance caused by subcutaneous edema.

Figure 6. Cellulitis. Note the cobblestone appearance caused by subcutaneous edema.

 Figure 7. Example of anisotropy. Note the change in the flexor tendon from a hyperechoic signal (star) to a hypoechoic signal (arrow).

Figure 7. Example of anisotropy. Note the change in the flexor tendon from a hyperechoic signal (star) to a hypoechoic signal (arrow).

Scan in two planes, and compare to the contralateral side if needed. Because of anisotropy, be sure to hold the probe perpendicular to the tendon in order to avoid mistaking tendon for fluid.

False negatives can occur with ultrasound in early PFT when fluid accumulation is minimal, so clinical suspicion based on all information gathered should guide clinical management.

TREATMENT

Once PFT is suspected, it is important to initiate empiric antibiotic therapy—commonly vancomycin and/or piperacillin/tazobactam—to improve clinical outcomes (14). Elevate the hand to reduce swelling. Definitive treatment, however, is surgical incision and drainage, so early consultation of a hand specialist is also necessary. Cultures can be obtained in the OR and antibiotic therapy narrowed once speciation and sensitivities are determined.

Although success with non-surgical treatment has been described, no studies have evaluated outcomes for PFT with antibiotics alone, and further investigation is warranted (14).

CASE OUTCOME

The patient was started on vancomycin, and orthopedics was consulted. She was taken to the OR for an emergent incision and drainage that was notable for the release of frank pus from the index finger flexor sheath as well as murky fluid in the palm. Piperacillin/tazobactam was added, and the patient showed gradual improvement in erythema, swelling, and range of motion throughout her hospital course. Speciation and sensitivities revealed methicillin-sensitive Staphylococcus aureus (MSSA), and antibiotics were narrowed. The patient was transitioned to oral antibiotics and discharged on post-operative day #4 with orthopedic follow-up.

TAKE HOME POINTS

  • Pyogenic flexor tenosynovitis can result in significant morbidity and is a surgical emergency.
  • Kanavel’s signs are used to diagnose PFT, but remember that the absence of Kanavel’s signs does not exclude early PFT:
    • Fusiform swelling.
    • Finger held in flexion.
    • Pain with passive extension.
    • Tenderness along the flexor tendon sheath.
  • Point-of-care ultrasound is a helpful tool in distinguishing PFT from other causes such as cellulitis or abscess.
  • Consider using the water-bath technique to image the hand.
  • Look for hypoechoic or anechoic fluid within the tendon sheath or thickened tendons.
  • If PFT is suspected, start broad-spectrum empiric antibiotics, splint and elevate the hand, and consult a hand specialist for possible operative management.

Faculty Reviewer: Dr. Jeff Feden

REFERENCES:

(1) Weinzweig N, Gonzalez M. Surgical infections of the hand and upper extremity: a county hospital experience. Ann Plast Surg. 2002; 49(6):621-7.

(2) Glass KD. Factors related to the resolution of treated hand infections. J Hand Surg. 1982;7(4):388-94.

(3) Pang H-N, Teoh L-C, Yam AKT, et al. Factors Affecting the Prognosis of Pyogenic Flexor Tenosynovitis. J Bone Joint Surg Am. 2007;89(8):1742-8.

(4) Kanavel AB. Infections of the Hand. 1st ed. Philadelphia, PA: Lea & Febiger, 1912.

(5) Draeger RW, Bynum DJ Jr. Flexor Tendon Sheath Infections of the Hand. J Am Acad Orthop Surg. 2012 Jun;20(6):373-82.

(6) Kennedy CD, Huang JI, Hanel DP. In Brief: Kanavel’s Signs and Pyogenic Flexor Tenosynovitis. Clin Orthop Relat Res. 2016;474(1):280-4.

(7) Marvel BA, Budhram GR. Bedside Ultrasound in the Diagnosis of Complex Hand Infections: A Case Series. J Emerg Med. 2015;48(1):63-8.

(8) 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):260-2.

(9) Cohen SG, Beck SC. Point-of-Care Ultrasound in the Evaluation of Pyogenic Flexor Tenosynovitis. Pediatr Emerg Care. 2015;31(11):805-7.

(10) Schecter WP, Markison RE, Jeffrey RB, Barton RM, Laing F. Use of sonography in the early detection of suppurative flexor tenosynovitis. J Hand Surg Am. 1989;14(2 Pt 1):307-10.

(11) Jeffrey RB Jr, Laing FC, Schecter WP, Markison RE, Barton RM. Acute suppurative tenosynovitis of the hand: diagnosis with US. Radiology. 1987;162:741-2.

(12) Hmamouchi I, Bahiri R, Srifi N, Aktaou S, Abougal R, Hajjaj-Hassouni N. A comparison of ultrasound and clinical examination in the detection of flexor tenosynovitis in early arthritis. BMC Musculoskelet Disord. 2011;12:91.

(13) Alcalde M, D’Agostino MA, Bruyn GAW, Möller I, Iagnocco A, Wakefield RJ, Naredo E. A systematic literature review of US definitions, scoring systems, and validity according to the OMERACT filter for tendon lesions in RA and other inflammatory joint diseases. Rheumatology. 2012;51(7):1246-60.

(14) Giladi AM, Malay S, Chung KC. Management of acute pyogenic flexor tenosynovitis: literature review and current trends. J Hand Surg Eur Vol. 2015; 40(7):720-8.

Thumb’s Up for Diagnosing and Managing UCL Injuries

Case

32 year old right handed man presents with right thumb pain after a mechanical fall from standing onto steps.  While falling, his outstretched thumb caught on a step.  He denies other injury.  On exam, he has pain and swelling at the thumb MCP joint.  There is a palpable lump on the ulnar side of the base of his thumb.  He has full ROM and intact strength in the affected digit.

What are the next steps in this patient’s management?

Epidemiology

  • Most commonly occur in athletes when a force causes thumb abduction
  • Skiing accidents in which the thumb is abutted against a fixed pole are the prototypical injury
  • More common in males with a ratio of 3:2
  • Complete ulnar collateral ligament tears can occur by non-sport related falls, motor vehicle crashes in which the hands are on the steering wheel, or bicycle injuries from handlebars

UCL anatomy

  • Runs from middle of metacarpal head to the volar aspect of the proximal phalanx
  • Provides structural strength to the thumb
  • Resists valgus load to thumb

Mechanism of Injury

  • Hyper-extension or abduction of the thumb causes the UCL to avulse from the proximal    phalanx
  • Acute injuries result in a complete or partial tear of the ligament
  • Avulsion fractures of proximal phalanx may or may not be present

Clinical Presentation

  • Acute injuries present with pain and swelling of the base of the thumb
  • Chronic injuries, also known as Gamekeeper’s thumb, present with loss of strength of the   thumb and deformity

Traditionally, this injury was originally described in people who manually and repetitively sacrificed small game by breaking the animal’s neck.

Unknown.jpeg

Exam

  • Cornerstone of diagnosis
  • Goal of exam is to evaluate joint stability
  • Valgus stress of the MCP joint reveals increased laxity
  • Test in both neutral position and with MCP joint fully flexed.  Fully flexing the joint isolates the UCL from the volar plate, which can provide additional stability
  • Angulation of >35 degrees, or a difference of >15 degrees between hands signifies a        positive test.
  • In partial tears, the loss of a distinct endpoint while stressing may be noted

Stener lesion

Occurs when the proximal end of the completely torn ligament is pulled from its normal location deep to the abductor aponeurosis and then fails to reduce itself properly, remaining superficial to the aponeurosis   

  • Present in up to 50% of complete UCL tears.
  • Exam may note a palpable lump
  • Surgical intervention is required
  • Stressing the MCP has NOT been shown to cause a Stener lesion where one did not already exist.
  • Pinch grip may be reduced in both acute and chronic injuries

ED Evaluation

  • Plain films to evaluate for avulsion fracture of proximal phalanx
  • Stener lesion will not be evident of plain films
  • Ultrasound has not been fully validated in diagnosis UCL tears
  • MRI is not cost effective in the ED, but may be obtained in follow-up in consultation with a hand surgeon

ED Management

  • Thumb spica is hallmark of ED management, allowing for immobilization of thumb MCP joint
  • If joint deemed unstable, follow-up within 1 week to a hand surgeon is advised to allow for surgical planning.  A delay in surgery can cause contracture of the UCL and increases  likelihood of chronic instability
  • For stable injuries, non-urgent follow-up within 4 weeks is recommended.

Faculty Reviewer: Dr. Kristina McAteer

References

  • Germano, T.  Falls on the Out-Stretched Hand and Other Traumatic Injuries of the Hand and Wrist: Part II.  Emergency Medicine Reports:  The Practical Journal for Emergency Physicians.  Volume 28, Number 18.  August 20, 2007.
  • Gammons, M et al.  Ulnar collateral ligament injury (gamekeeper's or skier's thumb).  Retrieved from UpToDate.com.  Accessed 4/21/2018.
  • Richard, JR.  Gamekeeper’s Thumb:  Ulnar Collateral Ligament Injury.  Am Fam Physician.  19

 

Les Midfoot Fractures: A Franc Review

Case 

A healthy 33-year-old female presents after a mechanical fall while jogging. She stumbled while stepping from the curb and fell forward into the street. She has severe right ankle and foot pain and is unable ambulate. On examination, there is diffuse swelling of her right foot and ankle with tenderness throughout, especially at the dorsal aspect of the foot. There is a small amount of plantar ecchymosis. X-rays of the foot are obtained.

Case AP XR.jpg

What is your next move?

Do you provide the patient with and ace wrap and crutches and discharge her home? What else should be considered? Are the details of her mechanism helpful?  Are there radiographic findings suggestive of occult fracture? What examination findings are suggestive of an occult pathology?

Introduction 

Originally described during the Napoleonic wars without the aid of multidetector computed tomography scanners, Lisfranc injuries remain an important consideration in foot trauma but are fraught with diagnostic challenges. Often describing a fracture/dislocation to any portion of the tarsometatarsal joint complex, Lisfranc injuries can lead to significant morbidity and functional impairment if missed (which occurs in up to 20% of cases). The stability of the complex is primarily conferred by the articulation of the second metatarsal with the middle cuneiform and the Lisfranc ligament (oblique interosseous ligament) which connects the base of the second metatarsal with the medial cuneiform.

Mechanism of Injury 

The key to making a correct diagnosis begins with a high index of suspicion based on history (e.g. mechanism) and exam because radiographic findings may be subtle. Direct injury is usually from blunt trauma to the dorsal foot or from crush injury. Indirect injuries are often associated with extreme hyperplantarflexion or rotation of a fixed midfoot. Other common mechanisms include motor vehicle collisions and sports that require stirrups, bindings, or foot straps. Interestingly, one third of Lisfranc injuries are associated with seemingly minor mechanisms.

Radiograph Review 

Lisfranc injuries range from subtle, sometimes undetectable subluxations to obvious fracture-dislocations. A methodical review of x-rays is essential to assessing for a Lisfranc injury. Special attention should be paid to alignment and focuses on two key relationships. First, the medial borders of the second metatarsal and the middle (second) cuneiform should be well-aligned on the AP view, as should the lateral borders of the first metatarsal and the medial (first) cuneiform. Second, the distance between the first two metatarsals should be examined, as this distance is commonly increased with Lisfranc injuries. Widening between the metatarsals and/or cuneiforms may be more apparent with oblique views.

Suggestive Exam Findings

  • Inability to ambulate or stand on toes
  • Significant pain/swelling of the midfoot
  • Plantar ecchymosis
  • Positive pronation-abduction test (pain with forefoot abduction and pronation with fixed hindfoot)

Suggestive Radiographic Findings

  • Widening between the first and second metatarsals and/or medial and middle cuneiforms – Image 3
  • Malalignment of the first and second metatarsals with the medial and middle cuneiforms, respectively, on the AP view (as described above) – Image 4
  • Malalignment of the medial and lateral borders of the third metatarsal and lateral cuneiform on the oblique view
  • Malalignment of the medial borders of the fourth metatarsal and cuboid on the oblique view
  • Fleck sign (avulsion fracture of second metatarsal base) – Image 5
  • Step-off sign (dorsal metatarsal displacement) on lateral view
  • Cuboid or cuneiform fractures

Image 3: Radiograph demonstrating widening between the first and second metatarsals (Click to expand)

Image 4: Radiograph demonstrating malalignment of the medial and lateral borders of the third metatarsal and lateral cuneiform (Click to expand)

Image 5: Radiograph demonstrating the "fleck sign." Indicative of an avulsion fracture of the base of the second metatarsal (Click to expand)

Role of CT  

Interpretation of radiographs may be limited secondary to suboptimal positioning and the inherent overlapping bony articulations of the midfoot. Classically, weight-bearing views are suggested; however, adequate weight-bearing views are often limited by pain. Advanced imaging is advantageous in these cases and allows for visualization of subtle findings in multiple planes. A CT should be obtained if the diagnosis remains in question despite normal-appearing radiographs if there are suggestive exam findings or the patient is unable to bear weight.

Management 

When improperly managed, Lisfranc injuries can lead to pes planus deformity and functional limitations secondary to arthritis and pain with weight bearing. Stable ligamentous injuries (with displacement <2mm) may be managed conservatively with short leg casting and non-weight bearing for 6 weeks. Stability can be reassessed with weight bearing radiographs at two weeks. Prior to proceeding with non-operative management, advanced imaging should be considered to better evaluate the extent of injury. Unstable or displaced injuries are typically managed with open reduction and internal fixation. In the emergency department, orthopedic consultation is recommended in all suspected or confirmed cases of Lisfranc injury.

Key Points

  • A high index of suspicion must be maintained to identify subtle Lisfranc injuries. Foot pain and swelling after trauma, especially when associated with inability to bear weight, should be suspected of having a Lisfranc injury.
  • The second metatarsal base should always be carefully assessed for displacement, avulsion, and fracture. The alignment of the second metatarsal with the middle cuneiform and spacing between the first and second metatarsals are the most consistent and easily assessed relationships on AP radiographs.
  • CT scan should be obtained in cases of normal-appearing radiographs when there is remaining clinical suspicion.
  • Missed Lisfranc injuries can result in long-term disability.

Faculty Reviewer: Jefferey Feden, MD

Image Credits

  1. Courtesy Dr. Henry Knipe, radiopedia.org
  2. Courtesy Dr. Henry Knipe, radiopedia.org
  3. Courtesy RMH Core Conditions, radiopedia.org

References

Desmond, E. A., & Chou, L. B. (2006). Current concepts review: Lisfranc injuries. Foot Ankle Int, 27(8), 653-660.

Englanoff, G., Anglin, D., & Hutson, H. R. (1995). Lisfranc fracture-dislocation: a frequently missed diagnosis in the emergency department. Ann Emerg Med, 26(2), 229-233.

Foster, S. C., & Foster, R. R. (1976). Lisfranc's tarsometatarsal fracture-dislocation. Radiology, 120(1), 79-83.

Gupta, R. T., Wadhwa, R. P., Learch, T. J., & Herwick, S. M. (2008). Lisfranc injury: imaging findings for this important but often-missed diagnosis. Curr Probl Diagn Radiol, 37(3), 115-126.

Hunt, S. A., Ropiak, C., & Tejwani, N. C. (2006). Lisfranc joint injuries: diagnosis and treatment. Am J Orthop (Belle Mead NJ), 35(8), 376-385.

Lau, S., Bozin, M., & Thillainadesan, T. (2017). Lisfranc fracture dislocation: a review of a commonly missed injury of the midfoot. Emerg Med J, 34(1), 52-56.

Perron, A. D., Brady, W. J., & Keats, T. E. (2001). Orthopedic pitfalls in the ED: Lisfranc fracture-dislocation. Am J Emerg Med, 19(1), 71-75.

Ross, G., Cronin, R., Hauzenblas, J., & Juliano, P. (1996). Plantar ecchymosis sign: a clinical aid to diagnosis of occult Lisfranc tarsometatarsal injuries. J Orthop Trauma, 10(2), 119-122.

Watson, T. S., Shurnas, P. S., & Denker, J. (2010). Treatment of Lisfranc joint injury: current concepts. J Am Acad Orthop Surg, 18(12), 718-728.