Monday, October 14, 2013

Acute Carpal Tunnel Syndrome in Pediatric Distal Radius Fractures

Authors: Andrew W Phillips, MD MEd and Emily Niu, MD
Stanford University/Kaiser Emergency Medicine Residency Program and
Stanford University Orthopedics Residency Program

Summary points:
  • Acute carpal tunnel syndrome complicates up to 9% of distal radius fractures.
  • Large displacement increases the probability of developing acute carpal tunnel syndrome. 
  • Early carpal tunnel release is associated with improved outcomes.
The common scenario: An adolescent child crashes bicycle and presents with only L wrist pain. He reports mild numbness of his index finger but full sensation and movement are present on physical exam of the entire left hand. Is it a simple splint and follow up with orthopedics in a few days?

Click to enlarge.
Click to enlarge.




















Acute carpal tunnel syndrome (ACTS) is reported in 5-9% of all distal radius fractures in adults and children (1). The location of the median nerve overlying the central portion of the wrist and in the relatively compact median compartment makes it more susceptible than the other nerves of the hand. Median nerve contusion is also common in wrist fractures, and distinguishing it from ACTS can be challenging.

ACTS
Median Nerve Contusion
Appears gradually over hours
Appears at time of injury
Progressive signs and symptoms
Nonprogressive signs and symptoms
No change with elevation and dressing release
Possible improvement with elevation and dressing release
Table created from Schnetzler et al (2).

Severe initial displacement (>50% displacement and/or >20% angulation), regardless of reduction success, greatly increases the risk of ACTS in children with an odds ratio of 19 compared to less displaced fractures, p<.001 (3). This is per a single study of children ages 5-16 years old, 109 total participants, so its generalizability is limited, but the findings are notable enough that extra caution in severely displaced distal radius fracture pediatric patients is probably warranted.

Early intervention for carpal tunnel release has also been shown to improve outcomes and should be considered an urgent orthopedic consultation (4).

The particular aforementioned patient, despite near-anatomic reduction within approximately 2 hours of the accident went on to develop acute carpal tunnel syndrome and underwent carpal tunnel release later than night. He was discharged two days later with an unchanged neurovascular exam from prior to the carpal tunnel release but with full motor function of his left hand.

References

1. Niver GE, Ilyas AM. Carpal tunnel syndrome after distal radius fracture. Orthop Clin North Am. 2012 Oct;43(4):521-7. PubMed PMID: 23026468.
2. Schnetzler KA. Acute carpal tunnel syndrome. J Am Acad Orthop Surg. 2008 May;16(5):276-82. PubMed PMID: 18460688.
3. Nietosvaara Y, Hasler C, Helenius I, Cundy P. Marked initial displacement predicts complications in physeal fractures of the distal radius: an analysis of fracture characteristics, primary treatment and complications in 109 patients. Acta orthopaedica. 2005 Dec;76(6):873-7. PubMed PMID: 16470445.
4. Mack GR, McPherson SA, Lutz RB. Acute median neuropathy after wrist trauma. The role of emergent carpal tunnel release. Clin Orthop Relat Res. 1994 Mar(300):141-6. PubMed PMID: 8131326.


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