Based on the research it is clear to see that Knee OA is a major challenge for our health care system. Many avenues of treatment have been attempted with minimal success. Manual therapy shows promise in assisting with short term functional outcomes (WOMAC), prevention of surgery and plausibly  a reduction of cost to the overall heath care system. Here are the facts:  The estimated cost of OA/year: $60 billion in the United States. Knee OA: 19-37% of adult Americans, with increasing likelyhood as age increases. The estimated cost of TKA/year in the United States is $11 billion.  Given these numbers it is clear that interventions are needed to minimize the impacts of Knee OA. Fortunately, there are a few baselines to work from.
Surgery: In a study by Kirkley et al of 178 patients it was found that knee surgery failed to show superiority over the control group at 2 year follow up. The outcome measure used was the WOMAC. Similarly, the study by Moseley et al of 165 patients showed that there was no benefit of surgery at any time point versus the placebo group. This study used the Knee specific pain scale as the outcome measure. Given the results of the surgical interventions and the costs involved with these surgeries, it is clear to see that surgery is not the solution for knee OA.
So we must look for different solutions to this problem. Perhaps standard physiotherapy is the answer. A systematic review by Jamvedt et al found that few comparisons could be graded as high quality evidence. Only exercise for reducing pain and improving function and weight loss for disability were supported by high-quality evidence. BAH that sure is discouraging for physiotherapy. It is important to note that they did not review any studies that looked at Manual Therapy interventions. Fortunately, a couple studies by Deyle et al have shown promise as a plausible solution.
The first study took place in 2000 with a sample of 83 patients. At 1 year, patients in the treatment group had clinically and statistically significant gains over baseline WOMAC scores and walking distance; 20% of patients in the placebo group and 5% of patients in the treatment group had undergone knee arthroplasty. It is useful to note that the outcome measure used here was the WOMAC just as it was in the study by Kirkley et al. Likewise, this outcome measure was used in the second study by Deyle 2005. Based on clinical criteria developed for Knee OA by Altman of 1. Knee pain and crepitus with active motion and morning stiffness 30 min and age more than 38 y 2. Knee pain and crepitus with active motion and morning stiffness #30 min and bony enlargement 3. Knee pain and no crepitus and bony enlargement- which he found to be 89% sensitive eand 88% specific. The study of 137 patients they found that both the manual therapy and exercise group showed clinically and statistically significant improvements in 6-minute walk distances and WOMAC scores at 4 weeks; improvements were still evident in both groups at 8 weeks. By 4weeks, WOMAC scores had improved by 52% in the clinic treatment group andby 26% in the home exercise group. Average 6-minute walk  distances had improved about 10% in both groups. At 1 year, both groups were substantially and about equally improved over baseline measurements. Subjects in the clinic treatment group were less likely to be taking medications for their arthritis and were more satisfied with the overall outcome of their rehabilitative treatment.
This study was built upon to see which patients presenting with Knee OA would benefit from manual therapy to the hip. Using this study by Currier et al of 60 patients it was noted that 5 variables predicted successful treatment. Based on the pretest probability of success (68%), the presence of one variable had a positive likelihood ratio of 5.1 and increased  the probability of a successful response to 92% at 48-hour follow-up. If 2 variables were present, the positive likelihood ratio was 12.9 and the probability of success increased to 97%.
Clinically, we have had many cases of knee OA that we have treated over the years. Fortunately, the majority of my treatments have been focused on manual therapy and exercise. In hindsight I think I have put too much weight on the value of exercise and not on the value of manual therapy. There are pros and cons of implementing manual therapy. The costs specifically are related to paying for treatment. It might not be worth it if after 52 weeks the outcomes are the same anyway. Certainly, the pros are to allow active people to retain their quality of life in the short term. I would like to look into refining the research by Deyle to categorize which possible subgroups might benefit more from manual therapy versus exercise. I am quite certain that weight, age and gender variation would provide useful subgroups.

It is clear to see that Knee OA is a hugely challenging condition to treat. We need to find solutions that are clinically effective, useful at reducing surgery and cost effective. Of the research presented, a regionally interdependent approach to manual therapy for knee OA shows the best outcomes and most promise for future research. Come see your Physiotherapist for research based solutions.

Deyle G et al. Physical Therapy Treatment Effectiveness for Osteoarthritis of the Knee: A Randomized Comparison of Supervised Clinical Exercise and Manual Therapy Procedures Versus a Home Exercise Program. Physical Therapy . Volume 85 . Number 12 . December 2005
Currier LL et al. Development of a Clinical Prediction Rule to Identify Patients With Knee Pain and Clinical Evidence of Knee Osteoarthritis Who Demonstrate a Favorable Short-Term Response to Hip Mobilization. Physical Therapy Volume 87 Number 9
Deyle G et al. Effectiveness of Manual Physical Therapy and Exercise in Osteoarthritis of the Knee: A Randomized, Controlled Trial.Annals of Internal Medicine. Volume 132(3).February 1, 2000.173-181
Fitzgerald GK. Agility and Perturbation Training Techniques in Exercise Therapy for Reducing Pain and Improving Function in People With Knee Osteoarthritis: A Randomized Clinical Trial. Physical Therapy. 2011; 91:452-469.
Fitzgerald GK, Oatis C. Role of physical therapy in management of knee osteoarthritis. Current Opinion in Rheumatology 2004, 16:143–147
Jamtvedt et al. Physical Therapy Interventions for
Patients With Osteoarthritis of the Knee: An Overview of Systematic Reviews. Physical Therapy. Volume 88 Number 1
Kirkley et al. A Randomized Trial of Arthroscopic Surgery for Osteoarthritis of the Knee. n engl j med 359;11 september 11, 2008
Moseley JB et al. A controlled trial of arthroscopic surgery for Osteoarthritis of the Knee.. N Engl J Med, Vol. 347, No. 2 July 11, 2002