Posterior Long Arm Splinting Technique

Updated: Aug 06, 2021
  • Author: Lisa Jacobson, MD; Chief Editor: Erik D Schraga, MD  more...
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Application of Posterior Long Arm Splint

The posterior long arm splint should extend from the axillary crease to the wrist joint but should not include the metacarpals. It should cover the posterior surface of the arm behind the elbow. [11] The steps in splinting are as follows.

Apply the stockinette like a sleeve over the affected limb (see the video below).

Posterior long arm splinting. Measuring and placing sleeve.

Wrap the cast padding around the stockinette (see the video below). Use padding that is wider and longer than the plaster (or fiberglass) will be. Apply minimal extra padding to bony prominences and pressure points. Apply in a distal-to-proximal fashion.

Posterior long arm splinting. Applying cast padding.

Measure the appropriate length of plaster (see the video below). The simplest way to measure is to drape the stockinette over the appropriate part of the upper extremity and cut 5 cm extra on either side. Make the plaster slightly shorter than this template.

Posterior long arm splinting. Measuring plaster.

Tear 10 sheets of plaster. Submerge the plaster in water until no more bubbles appear. Squeeze the water out by running fingers along the length of the plaster three times. Laminate the plaster by running the palm over the plaster on a flat surface. Lay the plaster onto the padding, and fold the padding over the edges of the plaster (see the video below).

Posterior long arm splinting. Preparing and applying splint.

Apply the splint to the patient in the desired position. In the application of the splint, positioning depends on the injury. Typically, the posterior long arm splint maintains 90° of flexion at the elbow with neutral forearm and wrist positioning. The elbow, however, may be immobilized between 45° and 90°; the forearm may also be pronated or supinated, and the wrist may be flexed or extended.

A biomechanical study by Thompson et al found that the addition of one or two side struts to a long arm plaster splint significantly increased the load to failure and that a plaster cast with two side struts was comparable in strength to a half-fiberglass long arm cast. [12]

Once the splint is in position, secure it with an elastic bandage. The splint is permanently molded within 10 minutes. Recheck the patient’s neurovascular status. Place the patient’s arm in a sling.


Postprocedural Care

Provide appropriate discharge and follow-up instructions. These include instructions on resting, icing, and elevating the injured extremity and on keeping the splint clean and dry. If the patient received any sedation or opioids, advise against driving or alcohol consumption. Arrange timely follow-up in 1-5 days. Provide appropriate pain medication. If itching develops, consider prescribing an antihistamine (eg, diphenhydramine). If the itching persists or worsens, evaluate the splint for complications.



Complications of posterior long arm splinting include the following:

  • Thermal burns [13, 14] - Plaster hardens through an exothermic reaction, in which the amount of heat liberated is directly proportional to the setting process, which is based on the water temperature at which the splint is prepared; this reaction can cause burns if extremely hot water is used or if a barrier layer is not placed between the plaster and the patient’s skin
  • Pressure injuries [13, 15, 16] - This complication can be minimized by applying extra (thin) layers of padding at bony prominences
  • Contact dermatitis [13] - This complication can be minimized by ensuring full coverage of a clean dry extremity with the stockinette and providing adequate padding between the patient’s skin and the splinting material
  • Neurovascular compromise [13] – This complication can be minimized by documenting an intact neurovascular examination both before and after splinting; the patient should be reminded to seek immediate medical attention if he or she notices any decline in function or sensation of the extremity
  • Decreased range of motion - This complication can be minimized by encouraging timely orthopedic follow-up to prevent joint fusion