Agility and Perturbation Training Techniques in Exercise Therapy for Reducing Pain and Improving Function in People With Knee Osteoarthritis: A Randomized Clinical Trial 
G. Kelley Fitzgerald, Sara R.  Piva, Alexandra B. Gil, Stephen R. Wisniewski, Chester V. Oddis, James J. Irrgang
Phys Ther. 2011 Feb 17. [epub ahead of print]
Exercise therapy is often prescribed for patients with knee osteoarthritis (OA), particularly for patients who also demonstrate clinical and physical impairments. This exercise therapy is often targeted to address the observed impairments, whether they are reduced range of motion, quadriceps weakness or poor endurance. The authors state that these programs have only demonstrated moderate improvements in function and that the impairment-based programs do not address important motor control functions, including “quick stops, turns, and changes in direction; challenges to balance;  negotiating obstacles.” To overcome the inadequacies of these previous treatment programs, the authors tested a treatment paradigm that has shown success in restoring knee stability in patients after ACL injury; perturbation training.
In this single-blinded randomized controlled trial, 183 men and women were randomly assigned to either a group that received agility and perturbation training along with therapeutic exercise or a control group that consisted of a standard exercise program (muscle strengthening and stretching). The primary outcome measure was the Western Ontario and McMaster Universities self-report questionnaire WOMAC, although self-reported instability and pain were also measured. The global rating of change score and Get Up and Go test were also evaluated. After the interventions, self-report scores improved in both groups, although the improvement was not significantly greater in one group over the other. It is interesting to note two things however; 1) although not significant, the experimental group had lower (better) WOMAC scores at 2 and 6 month follow-ups and 2) self-report scores at 12 months were still significantly better than baseline, suggesting that the immediate improvements in self-reported function after the intervention were maintained for an entire year.
This article provides interesting insight into rehabilitation regimens for patients with knee OA. It appears that, on average, the addition of agility training did not have an added benefit. However, there may be a sub-group of patients with knee OA who would benefit more from this training. For example, patients who engage in higher level recreational or vocational activities may benefit from this type of training more than a person who has a mostly sedentary lifestyle. The authors also state that additional measures beyond the WOMAC may capture improvements associated with agility and perturbation training. Future studies should consider using a larger array of outcome measures to capture potential benefit. Going forward, predicting the individuals who are most likely to benefit from this specialized rehabilitation may provide optimal treatment planning. It also cannot be overlooked that even after discontinuing the treatment, both groups demonstrated persistent improvements in self-reported function at the 12 month follow-up. This finding provides more evidence for exercise therapy in patients with knee OA.
Written by: Joseph Zeni, Jr
Reviewed by: Stephen Thomas