77 year-old man presents to the ED with pain to his right hand following an accident on his motor scooter 4 days prior to arrival. He states he swerved into a field to avoid being struck by another motorist, lost control of his scooter, and as he laid the bike down his right hand was crushed by the scooter. He was wearing a helmet and sustained no other injuries.
Afebrile, vitals signs stable.
Examination of the right hand reveals a mildly edematous hand (diffusely along the dorsal surface of the metacarpals) with no point tenderness of the metacarpals or the carpal bones. No scaphoid tenderness. Skin examination is warm and dry, capillary refill is <2s. The 1st & 3rd-5th digits are nontender and have full ROM at the IP joints and the MCP joints. The 2nd digit is diffusely edematous with the IP joints held in partial flexion. There is tenderness along the volar aspect of the finger and the PIP joint is unable to be actively extended whatsoever. The DIP joint is able to be actively extended approximately 5-10 degrees. The skin of the 2nd digit has two small abrasions on the dorsal surface of the middle phalanx and the distal phalanx, and a small puncture wound on the volar surface of the base of the middle phalanx. The 2nd digit is diffusely tender to palpation. No purulence from the wounds, no induration, no fluctuance.
Evaluation and Management:
Based on the presence of Kanavel’s signs:
- finger held in partial flexion
- fusiform swelling of the finger
- tenderness to palpation of the flexor tendon sheath
- pain/resistance to passive extension of the IP joints
The physician had a high index of suspicion for flexor tenosynovitis. Other considerations were a compartment syndrome from a crush injury, a localized abscess or multiple fractures. An IV was started, basic labs were drawn, moprhine as given for analgesia and radiographs of the hand were requested. An emergent consult was placed to hand surgery which was being covered by plastic surgery this evening.
No fracture or dislocation was identified on the radiographs. A POC US of the right finger was then performed revealing the following images:
The first image demonstrates a longitudinal view of the volar surface of the 2nd finger demonstrating the hyperechoic middle phalanx in the far field with the flexor tendon anterior to the bone surrounded by anechoic fluid anteriorly and posteriorly (red stars represent abnormal fluid collections). The second image demonstrates a transverse view of the volar surface of the 2nd finger also demonstrating the tendon completely surrounded by anechoic fluid (red star represents abnormal fluid within the tendon sheath).
ED Course & Management:
After the US exam the physician ordered empiric antibiotics for a skin/soft tissue infection of the right index finger. The resident from the plastic surgery service evaluated the patient and felt that the patient likely had an abscess rather than tenosynovitis and performed an I & D at the site of the puncture wound on the volar surface of the finger. She did not obtain any purulent fluid. The wound was dressed and the patient was admitted to medicine with plastic surgery following as a consultant. Approximately 14 hours after being admitted to the hospital, the patient was taken to the operating room where an wide I & D was performed and upon entering the tendon sheath, purulent fluid was identified and evacuated.
The patient went on to have uncomplicated post-operative course and was discharged from the hospital with a volar splint in place and on oral antibiotics.
Summary & Learning Points:
Flexor tenosynovitis is a tricky diagnosis and requires a high index of suspicion. Oftentimes it can be difficult to convince consultants that a patient requires further evaluation or an operation. POC US can be a useful tool to convince yourself that this patient is worth pushing all your chips into the middle for, rather than blindly following the consultants over the phone recommendations which initially will often consist of a strategy that will keep them sitting at home (antibiotics and d/c with next day clinic follow-up).
See the attached article for a case report on POCUS diagnosis of flexor tenosynovitis of the wrist.