Kulig K, et al. Nonsurgical Management of Posterior Tibial Tendon Dysfunction With Orthosis and Resistive Exercise: A Randomized Controlled Study. Physical Therapy, 2009, 89: 26-37.

This study was designed to determine the efficacy of different non-surgical interventions in clients with symptomatic dysfunction of the posterior tibialis tendon. All 36 subjects had been classified into Stage I or Stage II. Stage I and II exhibit progressive levels of medial foot pain, localized edema, and the ability to perform a heel raise (with some possible level of pain). Flattening of the arch occurs in Stage II. Subjects were excluded if there was any rigid foot deformity. Subjects were randomly assigned to one of three groups. Each group wore a foot orthosis to support the foot and reduce collapse during weightbearing. Two groups also completed an exercise program, one with concentric exercise, and one with eccentric exercise.

The subjects in each group performed static stretching of the gastroc-soleus group in the sagittal plane twice daily. The stretching regimen consisted of 6 stretches, each held for 30 seconds for 10 weeks. The group performing the additional exercises utilized an exercise device that allowed the foot to be loaded in the transverse plane: either concentric adduction, or eccentric control of abduction. Three sets of 15 repetitions were performed twice daily during the study period. The outcome measures used in this study were the Functional Foot Index (FFI), the 5-Minute Walk Test, and a Pain Score after the 5 minutes walk test.

The results showed that when the scores were averaged across all subjects, the FFI score reduced from 30.0 to 17.7. There was no statistical difference between distances walked before and after the study intervention, although the two exercise groups did walk further. The average pain score for the total group reduced from 26.9 to 6.0. The pain scores were lower for the two exercises groups, but not statistically different.

Why do the results of this study matter for function? First, the study shows improvement in “function.” Second, in spite of excellent scientific methodology, the results may be misleading to the casual reader. The study participants agreed to “discontinue athletic activities” once the study began. By attempting to control for functional stresses to the tissue, the subjects were required to reduce the activity that caused the symptoms. It seems possible that no intervention combined with reduction in activity for 10 weeks would reduce pain and improve scores on a self-report index. Additionally, adherence to the study protocol ranged from 39 % to 98%. The authors reported no difference between groups regarding adherence, but this highlights the negative aspects of averaging data. It would be interesting to know if subjects with greater than 80% adherence faired better than those below 50% adherence. Finally, the results in the strengthening groups were slightly better suggesting that the posterior tibialis muscle tendon unit was weak, and therefore would benefit from isolated strengthening.

A practitioner of Applied Functional Science® (AFS) would question whether these subjects were able to return to their previous level of activity without the return of symptoms. The Principles of AFS would acknowledge that every person is an individual, and therefore his / her treatment must be based on his / her responses to initial interventions. AFS practitioners, based on the fact that function is a Chain Reaction®, would not isolate the posterior tibialis in a non-functional manner. Instead, treatment programs would leverage the “truth” of Chain Reaction® by identifying impairments and improving function at other “links” in the kinematic chain.

This study was methodologically excellent, but the results are functionally of limited value. The authors are not to be criticized, but practitioners must recognize the limitations that study controls put on the usefulness of the results. Function is integration, not isolation. Therefore, our interventions must be integrated as well!