Page 102 - Journal of Special Operations Medicine - Spring 2014

a laceration to a complete amputation and include dam-
age to blood vessels, vessels, tendons and bone. 3

In a University of California study, investigators exam-
ined the biomechanics of ring avulsion injuries using a
cadaver simulation model and employing high-speed cin-
ematography and continuous force measurements. The Figure 2 New England
4
results determined that the skin provided the primary re- Journal of Medicine 352;6
Images in Clinical Medicine
sistance to injury and the investigators were surprised at February 10, 2005.
the small force necessary to produce complete amputa-
tion. A 30-pound weight applied over a distance of only
nine inches was sufficient to produce an amputation of
the finger in 41 of 44 specimens (Figure 1). The inves-
tigators questioned whether modifications to the ring’s
integrity are sufficient to prevent this type of injury.

Figure 1 Kupfer DM, Eaton C, Swanson S, McCarter MK, the injury from occurring. Secondary prevention is modi-
Lee GW. Ring Avulsion Injuries: A Biomechanical Study. fying a product’s design or use to minimize the injury.
J Hand Surgery (1999) 24A:1249–1253. In the case of ring avulsion injuries, primary prevention
occurs by establishing policies or practices that prohibit
operators from wearing rings during training or opera-
tions. Many industries, such as heavy manufacturing,
construction and mechanical work, employ these pre-
ventive strategies to prevent work-related ring avulsion
injuries.
Secondary prevention of ring avulsion injuries involves
modifying the ring. Techniques such as “ring notching”
or axial drilling are methods described to weaken the
ring and allow it to break away from the finger and
minimize injury if the ring becomes caught on an object.
Historically, amputation of the affected finger was the In ring notching, a jeweler weakens the ring by making
only treatment, but advances in microvascular repair a single cut completely through the ring and two equally
surgery permit surgeons to make an effort to spare the distributed secondary partial cuts along the sides (Figure
affected digit. The long-term consequences of a finger 3). In axial drilling, the jeweler cores through a cross
5
amputation are well-described. Amputation of the index section of the ring (Figure 4).
finger results in narrowing of the palm, causing up to a
20 percent decrease in grip strength in supination, and Figure 3 Frankleton, Wm F, et al. If you wear a ring, make it
up to a 50 percent loss of power in pronation. Efforts safe. Exhibit, American Academy of Orthopaedic Surgeons,
6
Chicago, IL, January 20–25, 1968.
at reimplantation or finger salvage using microsurgical
techniques are successful in 64 to 88 percent of patients.
When attempts at finger salvage were successful, patients
were left with a digit that has a restricted range of mo-
tion, some sensory loss and subjective cold intolerance. 7

The injury in Figure 2 occurred when the patient snagged
his ring while jumping over a fence. The small finger
with its tendon was amputated completely. A hand sur-
geon was able to reattach the finger and tendon success- Summary and Recommendations
fully. Note the persistence of deformity and swelling in Just as wearing eye and ear protection have become stan-
the finger. The subject’s range of motion remains limited. dard practices during operations and training, the wear-
ing of rings should also be prohibited to reduce these
injuries. A ring avulsion is an uncommon, but especially
Preventing the Injury
devastating, and potentially career-ending injury. It is
Primary prevention involves the modification of behav- preventable by not wearing a ring when engaged in ac-
iors through training, policy and practice so as to prevent tivities that may cause the injury. Because such activities

94 Journal of Special Operations Medicine Volume 14, Edition 1/Spring 2014