Intern Report 5.16

Case Presentation by Dr. Adam Bartsoff

CC: Right wrist pain

HPI: A 52 year old female presents to the emergency department accompanied by her daughter with the chief complaint of right wrist pain.  The patient states that approximately two hours ago she was walking down her basement stairs when she stumbled and fell the final two steps onto the basement floor.  Her fall was broken by an empty laundry basket and there was no LOC. Since the time of the fall, she complains of 10/10 throbbing pain in her right wrist and numbness and tingling in the fingers of her right hand. Additionally, her right wrist and forearm have become progressively more swollen.  Her wrist pain is exacerbated by movement of the joint and has not been alleviated by one extra strength Tylenol.

ROS: Negative except for that described in HPI and stress incontinence

PMH: Hypertension, Hyperlipedemia.

Meds: None

Allergies: PCN

PSH: Appendectomy, Cholecystectomy, C-section

Physical Exam:

Vitals: T  37.8, BP 165/100, HR 95, RR 20, SpO2 100% RA.

Gen: Healthy, well nourished appearing female. Cooperative. Sitting up in stretcher and holding right wrist with left hand.

HEENT: NC/AT. PERRLA, EOMI. Full ROM of Neck.  No C-spine tenderness/deformity.

NEURO:  Exam of right hand:

Light touch, pinprick and two point discrimination absent in palmer aspect of distal thumb, index and middle finger.  Sensation intact in ring finger, little finger and web space between thumb and index finger. Wrist extension intact, although painful.  Flexion of R MCP, PIP and DIP joints intact but painful.  Tinel’s sign weakly positive.

MSK: Obvious deformity of R wrist with dorsal angulation.  Decreased grip strength in right hand, 2/5. ROM of right wrist and digits elicits pain. Pain to palpation of right wrist and distal forearm. Symmetrical swelling of the R wrist and distal forearm.  Full ROM of elbow and shoulders bilaterally.

Skin: Mild erythema and swelling to R wrist with no tenting of skin or bony protrusion.

RESP: Clear to auscultation bilaterally with symmetrical chest expansion.

CVS: Tachycardic, S1, S2. No murmur, rubs or gallops. Radial pulses 2+ bilaterally.

Course in the ER:

The patient was given IV morphine for pain and radiographs of the right forearm were obtained.

Imaging:

imageinterpretation.co.uk

Questions:

1. What is the most frequent nerve damaged in this type of fracture?

(A) Median

(B) Radial

(C) Ulnar

(D) Axillary

(E) Vagus

2. Which of the following is a sign of instability in a Colles fracture?

(A) Intraarticular radiocarpal extension

(B) Distal radial ulnar joint extension

(C) Radial shortening

(D) Loss of radial inclination

(E) All of the above

3. Which of the following is true regarding the radial inclination?

(A) The correct radial inclination range is 15-20 deg

(B) Loss of radial inclination will increase the load across the Lunate

(C) The radial inclination is measured on the lateral radiograph

(D) A and B

4. What is a Smith’s fracture?

(A) An isolated fracture of the radial styloid process

(B) A reverse Colles fracture

(C) A fracture/dislocation of the volar rim of the radius

(D) An isolated fracture of the ulnar syloid process

 

Answers/Discussion

1) A

The radiograph demonstrates a Colles Fracture and the stem describes the classic presentation of an elderly person who falls on an outstretched hand.  The Colles fracture is a fracture of the distal radius with dorsal displacement and volar angulation.  It is the most common fracture of the wrist in adults and is especially more common in the elderly as they often have osteoporosis or osteopenia and are unstable ambulating. It was first described before the advent of radiology in 1814 by Dr. Abraham Colles who was an Irish surgeon. He defined a distal radial fracture as a “low-energy, extra-articular fracture to the distal radius in the elderly population.”

The radial, ulnar and median nerve’s are primarily responsible for sensation to the hand.  The sensory distribution of the hand is shown in figure 1.  The motor function of the hand is also primarily a function of the radial, ulnar and median nerves.  However, many of the motor functions of the hand are controlled by muscles originating in the forearm which are called extrinsic muscles. The muscles originating in the hand are called intrinsic muscles.  The radial nerve does not innervate an intrinsic

muscle. The radial nerve innervates forearm muscles responsible for extension of the wrist, thumb and MCP joints. The median nerve is responsible for thumb opposition and flexion of the thumb, index and middle fingers at PIP and DIP joints. Finally the ulnar nerve provides the most of the motor function of the intrinsic muscles of the hand. Ask the patient to hold a piece of paper between their index and middle fingers to evaluate ulnar nerve motor function.

Figure 1. Sensory Distribution of Hand (www.drtomaino.com)

For more on the normal hand exam see: Normal Hand Exam from practicalplasticsurgery.org

Neuropraxias can develop following a Colles fracture.  The most common nerve injured is the median nerve.  Because the median nerve travels through the carpal tunnel it is especially susceptible to compression and contusion as the wrist becomes more edematous following a fracture.  Patients may complain of paraesthesias in the distal palmer tips of the thumb, index and middle fingers.  Paralysis is usually transient if present. Patients may also develop ulnar and radial neuropraxias following a Colles fracture however they occur less frequently than median nerve injuries.

For anesthesia and analgesia during reduction of a Colles fracture the physician may perform a hematoma block. This is done by aspirating blood from the fracture hematoma and replacing it with 10-15 cc of 1% lidocaine. Allow approximately 10 minutes for proper anesthesia of the nerve fibers surrounding the periosteum and soft tissue. The efficacy of a hematoma block is best acutely and diminishes with time as the hematoma coagulates.

2) E

Intraarticular radiocarpal extension, distal radial ulnar joint extension, radial shorting and loss of radial inclination are all radiographic signs of instability and are high risk for patients to develop secondary displacement following primary reduction.

Indications or Instability:

  • > 10 degree loss of radial inclination
  • > 5 mm of axial radial shortening
  • > 2 mm of articular incongruity
  • Comminution of cortex across the midaxial line on lateral xray
  • Comminution of dorsal and palmer cortices
  • Irreducible fracture
  • Loss of reduction at follow up

Articular congruity is very important so that patients do not develop post traumatic arthritis of the wrist.

3) B

The radial height, inclination and tilt are three important measurements when interpreting radiographs of the forearm following a Colles fracture.  The radial height is measured on the PA radiograph and is the distance between two lines perpendicular to the long axis of the radius.  The first line is drawn to intersect the distal articular surface of the ulnar head and the second line is drawn at the distal tip of the radial styloid.  The average radial height is approximately 10-13 mm. See Figure 2.

Radial Height

Figure 2

Radial inclination is also measured on the PA radiograph.  Radial inclination is the angle between one line drawn between the radial styloid and the ulnar distal radius.  The second line is drawn perpendicular to the long axis of the radius. The average radial inclination is approximately 21 to 25 degrees.  Loss of radial inclination will result in increase load on the lunate complications in the future including post traumatic arthritis and potentially an operation.

Radial Inclination

Figure 3

Radial tilt is measured on the lateral radiograph.  It is the angle between a line that runs along the distal radial articular surface and the line perpendicular to the long axis of the radius.  The normal volar tilt is 11 degrees but has a range of 2-20 degrees.  See Figure 4.

Radial Tilt

Figure 4

4) B

A Smith’s fracture is also known as a reverse Colles fracture and is often mislabeled as a Colles fracture.  In a Smith’s fracture, the distal radius is fractured and the distal fragment is displaced volar instead of dorsal as in a Colles fracture.  This type of fracture is much more uncommon and is referred as a “garden spade” deformity. Likewise, a Colles fracture is sometimes referred to as “silver fork” deformity.

An isolated fracture of the radial styloid process is called a chauffeur’s fracture and is often associated with injury to the scapholunate ligament.  This occurs from tension forces sustained during ulnar deviation and suppination of the wrist. The name is derived from chauffeurs in previous eras who would have to start a car by hand cranking it.  When the car would backfire, the crank would violently snap back into the chauffer’s palm and produce the characteristic fracture.

A fracture/dislocation of the volar rim of the radius is known as a Barton’s fracture, specifically a volar Barton’s fracture.  This results from high velocity impact across the articular surface of radiocarpal joint with the wrist in volar flexion at the moment of impact.  Radiographs demonstrate a wedge-shaped articular fragment sheared off the volar surface of the radius and displaced volarly.  These fractures have a high tendency for redislocation and often require an operation.

An isolated fracture of the ulnar styloid process is rare and is often clinically insignificant.  However, fractures of the ulnar styloid process are often associated with fractures of the radius.

References:

Rosen’s Emergency Medicine. 7th editon. Page 467-477.

www.radiologyassistant.nl

Altizer, Linda L. Colles’ Fracture, Orthopaedic Nursing, March/April 2008

Figure 1. Sensory Distribution of Hand. www.drtomaino.com.

Normal Hand Exam practicalplasticsurgery.org

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