Background-After Achilles tendon repair, immediate weightbearing and immobilisation closer to neutral plantarflexion are thought to limit atrophy and stiVness, but may place deleterious stress on the repair. Objectives-To estimate the relative stress on the Achilles tendon during weightbearing with immobilisation in varying degrees of plantarflexion. Conclusions-When the ankle is immobilised, stress on the Achilles tendon is determined by the degree of plantarflexion and the contractile activity of the plantarflexors. In the immobilised ankle, the addition of a 1 inch heel lift was suYcient to minimise plantarflexor activity during walking. (Br J Sports Med 2001;35:329-334) Keywords: Achilles tendon; EMG; heel lifts; soleus; gastrocnemius Although there is still some debate about open versus closed management of Achilles tendon disruption, 1 2 most authors agree that surgical repair is the treatment of choice. Until recently, surgical repair followed by cast immobilisation in plantarflexion and non-weightbearing for six weeks was considered the ideal treatment. However, new controversy has arisen from recent studies that show that early mobilisation seems to enhance the healing of the repair.
Methods-Electromyographic3-9 Many authors are now advocating early range of motion (ROM) based on animal 10-14 and hand studies 15 that show increased healing rates and strength while preventing the side eVects of prolonged joint immobilisation, such as joint stiVness, muscular atrophy, cartilage atrophy, deep vein thrombosis, tendocutaneous adhesions, skin necrosis, and disuse osteoporosis.2 8 16 17 If the tendon experiences tension during healing, orientation of collagen fibres and strength of the calf muscles are improved, as are tendon vascularity, 11-13 18 breaking strength, and number of collagen filaments. 19 With early ROM and weightbearing protocols, patients are obtaining power and strength that is almost equal to that of the opposite good leg.3 5 6 8 By contrast, repair followed by six weeks of cast immobilisation results in appreciable residual weakness. 1 20-22 Early ROM and progressive weightbearing appear to result in few failures or complications.5 23-25 However, there is limited clinical research available on which to base the timing and progression of rehabilitation after Achilles tendon repair. For example, cam-walkers are commonly used to provide protected weightbearing by immobilising the ankle in varying degrees of plantarflexion. However, the degree of protection aVorded to the Achilles tendon with the use of such immobilisers is not known.When the ankle is immobilised, stress on the Achilles tendon during gait is determined by the degree of plantarflexion and the contractile activity of the plantarflexors. The degree of plantarflexion can be controlled by using a ROM adjustable cam-walker. Alternatively, cam-walkers with the axis fixed at 90°can be used, and increased plantarflexion can be achieved by inserting heel lifts into the camwalker. The magnitude of contractile activity during...