189 Anterior Ankle Surface Pressures in Lower Extremity Splints: Minimizing Insult After Injury

Abstract

Though ubiquitously utilized in lower extremity orthopaedic trauma, lower extremity splints are not without their associated iatrogenic risk of morbidity. In fact, improper splinting not only necessitates replacement, but splint- related soft tissue complications are the second most common iatrogenic cause for referral to plastic surgery. Pressure ulcers result from perpendicular forces that compress the soft tissues between body mass, bony prominences, and the support surfaces below. Within those soft tissues are vessels that run parallel to the surface of the site of skin collapse and may collapse easily from pressure loads. As such, prolonged pressure above the threshold for capillary tolerance results in occluded blood flow, interstitial fluid flow, ischemia, pain, necrosis, and sloughing of dead tissue. While clinicians commonly pad bony prominences to minimize the skin pressure, the effect of joint position on skin pressure and, more specifically, changing joint position, is real but has not been well studied or described. The purpose of this biomechanical study is to identify problems with anterior ankle skin pressure secondary to joint position change during splinting and ultimately to determine the optimal position of the ankle during application of the splint as well as the padding technique required over the anterior ankle to minimize iatrogenic skin pressure ulcers. Following ethics approval by our institutional review board, various constructs of lower extremity, short-leg splints were applied to two healthy subjects (two limbs total in this preliminary data set) with an underlying pressure transducer (Tekscan® I-Scan® system, (Tekscan Inc, South Boston, MA, USA) on the skin surface centered on the anterior ankle on the tibialis anterior tendon. All subjects underwent anterior ankle surface pressure assessment when padding was applied in maximum plantar flexion and neutral position for conventional short leg splints application. Percent change from initial contact pressure centered on the tibialis anterior with either Webril© (Covidien/Medtronic, Dublin, Ireland), or Specialist© Cotton Blend Cast Padding (BSN Medical, Charlotte, NC, USA) were calculated. Neutral position of the foot/ankle will be confirmed with a goniometer. There were two limbs total that were analyzed for presentation of pilot data for this study. The percent change in anterior ankle contact pressure when padding was applied in maximum plantar flexion (PF) and then placed in neutral was increased at least two-fold without the addition of plaster and subsequently with the addition of plaster in lower extremity short leg splints (Figure 1). In this pilot data, we report significant increases in anterior ankle contact pressures when splint padding is applied in plantar-flexion and re-positioned into neutral during splint application which may precipitate iatrogenic pressure ulcers. This data, though preliminary, underscores the importance of proper splinting techniques for all clinicians that manage lower extremity trauma (eg, orthopaedic surgery, emergency medicine, urgent care, etc).