In my everyday practice of orthopaedic trauma, we deal with a whole range of injuries. They range from simple non-displaced distal radius that require little more than careful watch, to complex acetabular factures that require upwards of 10-12 hours of surgery. Out of all of the potential post operative problems that can arise as a sequela, non-unions are some of the most troublesome. The exact etiology can be elusive and multi-factorial. There are several direct mechanisms that can have a direct correlation to the rate of healing such as personal habits as well as current co morbid conditions,.. Accordign to ………………. Smoking is related to …………………. Also noteoworthy, diabetes………………….. After all of the potential external stimuli have been excluded, the best modality to aid in the treatment is can be a sort of gray area in medicine.
One area that is showing a fair amount of evidence in its favor is the use of low intensity pulsed ultrasound. The prime candidate is for a post traumatic surgically corrected patient and is not showing adequate bone healing. The time frame can be subjective, although some degree of callous formation should be noted radio-graphically within 90-115 days post operatively (…). One sub-acute infection has be thoroughly ruled out, the predominante reason for non union is non-osseous fibrous callous. The exact mechanism for this fibrosis is not known, although there are several theories that elude to overall metabolic dysfunction of unknown etiology. The mechanism for the devices to be carried out entails application directly to the skin on a pre-determined area that has been corresponded radiographically. Markings are then placed with either a permanent or semi-permanent marker, and the patient is directed to strap the device on the proscribed area(s) for 20 minutes per day. One of the benefits to this particular device is that it can be carried out in the patient's home, and there is no pain or sensation reported during its usage. Very often, patients forget to remove the device since there is no external stimulus noted. This is corrected by an alarm that is embedded in the device that keeps track of the time. The device is used for a minimum of 4-6 weeks with a peak noted by 20 weeks. According to the study performed by …….Cook et al… end point was determined by 1) no pain in manual stress, 2) radiographic assessment with 3 of 4 cortices bridged.
The exact mechanism of action is not entirely clear at this point and much debate has ensued. What is known is that the micro movement of the pulsed ultrasound changes the fluid dynamic which has shown to increase nutrient delivery and waste removal (…).
In the article by Heckman……. they studied in a prospective, randomized, double blinded, placebo fashion, the use of ultrasound in tibial shaft fractures. Both closed and grade 1 open fracture in which 67 factures were enlisted. 33 fractures were treated with low intensity pulsed ultrasound compared to 34 with placebo. Treatment was started within 7 days of injury and consisted of a single 20 treatment each day. At the end of the study, a significant reduction in healing time was observed in the active group (86 days) when compared to placebo (114) (……). There was also a reduction in subjective complaints of pain by the treated group versus the placebo.
The second article of ………………. By Rubin, Bolander,…… delves further into the overall history of the use of low intensity ultrasound in both animals and humans. It is also a current concepts review, which collates a series of studies and provides a synopsis of each. A history is provided that begins with the first usage documented in Italy with radial fractures in rabbits, in that pulsed ultra sound was used and shown to increase callous formation. The article brings forward studies that investigate several areas to include: femur, humerous, metatarsal, radius or ulna, scaphoid, and tibia. It too reported decreased rates of healing in each study with very little variation on the time or overall duration. (PUT MORE INFO ABOUT STATS IN EACH STUDY)
In our practice, there is a certainly a place for the use of low intensity pulsed ultrasound, although the exact timing of when to use it, is still in question. Often there are other avenues to pursue to rule out any other sub acute problem. Is it an indolent infection? Is it due to body habitus? Is it more of a peripheral circulatory problem?