The Rationale of Functional Bracing of Fractures

Abstract

Fracture bracing is a philosophy rather than merely the use of orthotic devices in the treatment of fractures. It is predicated on the belief that immobilization of the fragments and the joints above and below the fracture is not necessary for fracture healing. It proposes also that the soft tissues of the injured extremity play a major role in providing the stability necessary to allow uninterrupted osteogenesis.The encouraged early function, weightbearing and motion of the joints and fracture fragments during treatment challenges the basic concepts of surgical as well as nonsurgical fracture management which emphasize that rest and fragment immobilization are prerequisites for fracture healing. In an effort to elucidate these conflicts and gain a better understanding of how bracing works, a series of laboratory studies was c~n d u c t e d .~~~~~~~~This article provides a synopsis of the important portions of this research as they apply to fracture bracing. VASCULARITY AND FRACTURE HEALINGAt the time of a diaphyseal fracture, the normal blood supply to the bone is disrupted and a hematoma forms at the fracture site. Medullary circulation is almost always disrupted and is slow to re-establish. Subsequently, capillaries invade the area of the fracture site from the peripheral soft tissues. The importance of the early revascularization from soft tissues is emphasized by the close association of early bone formation with vascular invasion (Fig. 1). A possible explanation for the new bone formation following the capillary invasion was offered by Trueta, who suspected endothelial metap1a~ia.I~ Much of our work has supported this theory by demonstrating the close proximity of osteoblastic and osteoclastic activity to the invading vasculature (Fig. 2 ) .Thus, one important role of function in fracture healing can well be the early vascular invasion stimulated by muscle activity. When function is introduced early in this nonsurgical management regimen, the activity level of the osteoblasts and osteoclasts is high as indicated by light and electron microscopy (Fig. 3). FRACTURE CALLUS ARCHITECTUREThe importance of the gross architecture of callus formation when healing takes place in the presence of function and muscle activity is based upon the structural role of bone. The callus architecture forms in the following manner: initially, a hematoma surrounds the area near the fracture site and the bone ends and loose fragments become necrotic. Away from the fracture site early revascularization comes from medullary circulation. The callus formation at this point is of intramembranous origin, therefore 0009-921X/80/0100/028 $00.95 0 J . B. Lippincott Co. 28

Functional treatment of closed humeral shaft fractures

“…Latta and coworkers [11] and Sarmiento and co-workers [17] noted that controlled movement at the fracture site is conductive for osteogenesis. In recent years, important studies have been published comparing plating and intramedullary nailing of the humeral shaft [3,6] but the role and justification of conservative treatment has not been called into question [10,19].…”

“…However, not all humeral shaft fractures are eligible for conservative treatment. Absolute and relative indications for surgical treatment have been described [1,11] (Table 1). Plaster splint, hanging cast and sugar tong splint were formerly used in conservative treatment.…”

Muscle contraction increases the strength of healing tibial fracture in the rat

“…The energy-absorbing capacity of the callus with soft tissues was doubled by muscle contraction. Latta et al (1980) found that the soft tissues carried over 80 percent of the load when they instrumented fracture braces on patients with fresh fractures of the tibia and fibula. Sarmiento et al (1974) and Latta et al (1980) concluded from their experiments that the brace and the soft tissues acted together as a hydraulic cylinder, which gave strength and stability to the fracture.…”

Functional splinting versus plaster cast for ruptures of the ulnar collateral ligament of the thumb: A prospective randomized study of 63 cases

“…It has been suggested that early motion enhances osteogenesis, promotes revascularization of the damaged tissue, and improves the biological healing process (Latta et al 1980, Sarmiento andLatta 1981). Many studies have shown a difference in the functional result after fractures and joint injuries between plaster cast immobilization and functional splints that was in favor of the splints, especially in terms of the earlier normalization of strength and range of motion (Sarmiento et al 1975, Arafa et al 1986, deBruijn 1987, Abbaszadegan et al 1989.…”