|
Dr.Wagner -> RE: case of the week Sept 23 (September 28, 2007 9:36:03 AM)
|
Radial head fracture with delayed compartment syndrome of the flexor forearm
Pathophysiology
Elevated intracompartmental pressure within the forearm is most common in the volar compartment or the combined volar and dorsal compartments. Although rare, CS may occur in the dorsal compartment alone.
CS may be the result of externally applied or internally expanding forces. It is most frequently associated with supracondylar fractures of the humerus and has been reported in conjunction with fractures of the radial or ulnar diaphysis and with surgical neck fractures of the humerus and following Colles fractures. In this case, the kimura, and the lack of care after the fracture, caused additional swelling and a cycle of injury.
The patient afflicted by CS may experience crescendo pain that is out of proportion to the original injury. The pain is deep and aching in nature and is worsened by passive stretching of the fingers. The patient may also describe a tense feeling in the extremity. Pain, however, should not be a sine qua non of CS. The forearm is often tender and tense, and the sensibility/sensitivity of the fingertips may be diminished.
Paraesthesia, or numbness, is an unreliable early complaint of CS5; however, decreased 2-point discrimination is a more reliable early test and can be helpful to make the diagnosis. Botte and Gelberman reported that 4 of 9 awake patients with compartment pressures higher than 30 mm Hg had median nerve 2-point discrimination of more than 1 cm.18 Correlation has also been reported between diminished vibration sense (256 cycles/s) and increasing compartment pressure.
On physical examination, evidence of trauma and gross deformity should alert the physician to the possibility of an evolving CS. Comparison of the affected limb to the unaffected limb is useful. Pulselessness is a late and unreliable finding, and the presence of a radial pulse does not exclude the possibility of a CS. The most important diagnostic physical finding is a firm, wooden feeling on deep palpation. Bullae may also be seen; however, so-called fracture blisters are common in the absence of CS. As the pressure increases, pallor and loss of pulses are late findings. If objective evidence of a motor deficit is found, the CS is far advanced. Laboratory testing that reveals a creatine kinase (CK) of 1000-5000 U/mL or greater or the presence of myoglobinuria can suggest CS.
CS in the hand most often occurs following iatrogenic injury in a patient who is obtunded in an intensive care unit. Symptoms may be nonspecific compared with those in other CS cases. Early recognition of this complication is based on physical examination and a high index of suspicion. Unlike elsewhere, CS in the hand lacks abnormalities in the sensory nerves, as no nerves are found within the compartments.
Consider the diagnosis when nonspecific aching of the hand, increased pain, loss of digital motion, and continued swelling are present. A tight, swollen hand in an intrinsic minus position—with the digits in metacarpophalangeal (MCP) extension and proximal interphalangeal (PIP) flexion—is highly indicative. Intrinsic tightness becomes evident on examination because motion of the PIP joint becomes dependent on the position of the MCP joint (more PIP motion is possible with MCP flexion than with MCP extension).
|
|
|
|