Orthoses for functional treatment of ankle fractures. A preliminary report.

This report examines the orthotic management of patients with ankle fractures. Two functional orthoses that allow movement in the talocrural joint are described. The results of using these orthoses on ten patients are discussed. Introduction Immobilization of an extremity, for example after a fracture, has certain unwanted effects. Osteoporosis arises (Enneking and Horowitz, 1972; Mattsson, 1972) and cartilage changes similar to those described at an early stage of osteoarthritis take place in the joint (Enneking and Horowitz, 1972; Langenskiöld et al, 1979). Changes also occur in ligaments and joint capsule (Finsterbush and Friedman, 1973; Videman et al, 1976; Langenskiöld et al, 1979), in synovial membrane (Finsterbush and Friedman, 1973), in muscles (Mattsson, 1972; Finsterbush and Friedman, 1973) and in blood flow (Semb 1969). So-called functional fracture treatment has been used in different types of fractures. It favours fracture healing but is also said to have beneficial effects on muscle function, joint mobility and time of rehabilitation (Sarmiento, 1967 and 1970; Sarmiento, Cooper, Sinclair, 1975; Sarmiento, Pratt, Berry, Sinclair, 1975; Mooney et al, 1970). However, Andersson and Nilsson (1979) did not find any difference in bone mineral loss in patients with tibial shaft fracture treated with or without weight-bearing and function. As far as we know, functional treatment has not been applied to ankle fractures which is why we started an investigation. This report only describes the orthoses used and the preliminary clinical impressions. Material and technique Our purpose, in a number of operated ankle fractures with supination—outward rotation injuries stage II-IV (Lauge-Hansen, 1942), was to compare cases treated postoperatively with conventional lower leg plaster and cases treated with an orthosis allowing movements in the talocrural joint. Classification of the fractures was made with the aid of Roentgen pictures and operative findings. Routine operative method was fixation of the fibular fracture with encircling wire/s. The fibula was secured against the tibia with Wiberg's staple/s and on the medial side pin/s or a screw have been used, or alternatively ligament suture (Cedell, 1967). Treatment of a possible posterior tibial fracture was individualized depending on size of fragment and degree of dislocation. Fig. 1. Top, the Isoprene R plastic shell is carefully modelled around the malleoli. Bottom, metal hinges and footplate are attached. Postoperatively the patient has been supplied with a split lower leg plaster. After a fortnight the plaster was removed and replaced with an irremovable orthosis permitting full dorsal and plantar flexion in the talocrural joint and full mobility in the knee and the toes including metatarsophalangeal joints. Pronation and supination of the foot was almost impossible. Two orthoses with the same functional principle have been tried out. For stability purposes the orthosis was originally made of plastic (Isoprene R. Johnson and Johnson) with metal hinges and foot plate, the foot plate being a semi-manufactured arch support. First of all a lower leg plastic shell was made and carefully modelled around the malleoli (Fig. 1, top). After the foot plate had been fixed to the metal hinges (Fig. 1, bottom) it was then fastened to the plastic shell and the foot with plastic slabs (Fig. 2). The other type of orthosis was made from plaster using a prefabricated plastic hinge with a foot plate (Fig. 3). The manufacturing process is essentially the same as the first orthosis described. The mobility of the ankle can be seen in Figure 4. The second orthosis is easier to make and is also much cheaper. The cost of the plastic orthosis is about 1600 Swedish crowns while the alternative costs only 300. The patients have been instructed and encouraged to move the ankle as much as possible. Clinical and Roentgenological checks have been made comparatively often and if required the orthosis has been adjusted or exchanged. After 6 (stage II—III) or 8 (stage IV) weeks, depending on the type of fracture, the orthosis was removed and the patient allowed Fig. 2. Footplate and hinges are fixed around the foot with plastic slabs. Fig. 3. Plaster shell orthosis with prefabricated plastic ankle with hinges for the talocrural joint. Fig. 4. The completed plaster shell orthosis showing the mobility of the talocrural joint. full weight-bearing. The clinical and Roentgenological checks continued until at least 10 or 12 weeks, respectively, after the operation.