We examined the recovery of power in the muscles of the lower limb after fracture of the tibial diaphysis, using a Biodex dynamometer. Recovery in all muscle groups was rapid for 15 to 20 weeks following fracture after which it slowed. Two weeks after fracture the knee flexors and extensors have about 40% of normal power, which rises to 75% to 85% after one year. The dorsiflexors and plantar flexors of the ankle and the invertors and evertors of the subtalar joint are much weaker two weeks after injury, but at one year their mean power is more than that of the knee flexors and extensors.

Our findings showed that age, the mode of injury, fracture morphology, the presence of an open wound and the Tscherne grade of closed fractures correlated with muscle power. It is age, however, which mainly determines muscle recovery after fracture of the tibial diaphysis.

We have carried out a prospective study to determine whether the basic descriptive criteria and classifications of diaphyseal fractures of the tibia determine prognosis, as is widely believed. A number of systems which are readily available were used, with outcome being determined by standard measurements including fracture union, the need for secondary surgery and the incidence of infection. Many validated functional outcomes were also used. The Tscherne classification of closed fractures proved to be slightly more predictive of outcome than the others, but our findings indicate that such systems have little predictive value.