Research Review: Manual Physical Therapy and Perturbation Exercises in Knee Osteoarthritis

Rhon et al, 2013

Study Design

Prospective, observational cohort study.


Fifteen participants (7 male, 8 female) with a mean age of 55 years old were recruited from a convenience sample of consecutive patients evaluated for knee osteoarthritis (OA) at the Physical Therapy Clinic, Brooke Army Medical Center, San Antonio, Texas. With regards to severity, ten patients had bilateral symptoms, all 15 patients had radiographic signs of knee OA, and 10 had visible boney enlargement of the knee joint. Additionally, four of the included patients were active duty military personnel.

Inclusion Criteria: Utilizing criteria proposed by Altman (1991) and Altman et al (1986), the participants were included if they met at least one of the following three clinical clusters.

1. Knee pain for most days of the prior month: AND Crepitus with active motion and Morning stiffness in knee 38 years
2. Knee pain for most days of the prior month: AND Crepitus with active motion and Morning stiffness in knee > 30 minutes and Bony enlargement
3. Knee pain for most days of the prior month: AND No crepitus and Bony enlargement

Additional inclusion criteria include being eligible for care in a military medical treatment facility, minimum age 38 years old, and the ability to read, write, and speak sufficient English to complete the outcome tools.

Exclusion Criteria: Only periarticular pain or pain referred from another region (no joint pain), injections to the knee within the last 30 days, history of knee joint replacement surgery on involved limb, evidence of other systemic rheumatic condition (lupus, rheumatoid arthritis, psoriasis, or gout), and balance deficits from other non-musculoskeletal conditions (neurologic impairments, diabetic neuropathy, cerebellar disorders, or Parkinson disease)


Outcome Measures: The Western Ontario and McMaster Universities arthritis index (WOMAC), Global Rating of Change (GROC), Functional Squat Test (FST) evaluated with numerical pain rating scale (NPRS) and range of motion (ROM), and the Step-Up Test (SUT). Additionally, tolerance to treatment was determined by asking the participants a series of questions regarding whether their symptoms had gotten significantly worse at five different time points since their last visit. Time points included were immediately following treatment, several hours following treatment, that evening prior to bed, the following morning, and from the following morning until the follow-up (approximately 72 hours later).

Evaluation: The initial evaluation included a detailed history, review of systems, and physical examination. The history included questions regarding the duration, severity, location, and distribution of symptoms. The physical examination included functional tests, palpation of bony landmarks, ROM measurement, muscle length tests, and manual assessment of the joints and soft tissues of the lower extremity.

Interventions: Each patient was treated two times per week for four weeks and received both manual therapy and perturbation interventions. Visits included joint and soft-tissue mobilization, which was supplemented with stretching, ROM, and strengthening exercises. Additionally, each patient was provided with a home exercise program targeting their specific functional limitations. The manual therapy techniques were tailored to the impairments of each individual patient, however these interventions included varying grades of knee flexion, knee extension, and patella mobilizations. With regards to perturbation training, each patient was progressed based upon clinical reasoning and as tolerated by the individual patient. Each program generally started with more emphasis on manual therapy interventions and towards the end of the program, the focus switched to perturbation exercises.


WOMAC: The mean WOMAC score demonstrated a statistically significant improvement from baseline to 6 months with a 46% improvement, which was well above the minimal clinically important difference (MCID) of 12%. Additionally, the total WOMAC score was significantly improved at the end of the 4 week intervention period and remained improved at the 6 month follow-up. Finally, the only WOMAC sub-scale that did not remain improved at the 6 month follow-up was the ‘Stiffness’ sub-scale.

GROC: At the one month follow-up, 87% of patients reached the 3 point change in GROC to identify a clinically important change. Changes decreased over time with 80% of patients still maintaining this threshold of change at 3 months and only 60% at the final 6 month follow-up. Additionally, and probably more importantly, 47% of patients met the threshold for ‘dramatic change’ (GROC > 6) at all time points.

FST: Following the 4 week intervention period, statistically significant improvements in NPRS and ROM during the FST were documented. An average decrease from 5 to 3 on the NPRS and an improvement from 29° to 35° with regards to ROM.

SUT: The Step-Up Test values also significantly improved at the 4 week evaluation with a mean improvement of 4-5 steps during the 15 second test. This translated to an average increase from 9 to 14 steps completed during the test.


Due to the prospective cohort design of this study, no comparison group was included, thus no cause and effect relationship can be identified. Additionally, some of the improvements seen in this study could be attributed to other medical treatment many of the patients received. By 6 months five patients had received knee joint injections of either corticosteroid or viscosupplementation and two of those same patients received arthroscopic surgery. Of these patients receiving either injection or arthroscopic surgery, none reported improvement in symptoms immediately following the aforementioned procedures. Pain medication was used by 12 patients initially (10 patients daily; 2 patients as needed), including non-steroidal anti-inflammatory drugs and/or acetaminophen. However, it should be pointed out that at each of the follow-up points, fewer patients were taking medications than at baseline.

Clinical Implications

While no cause and effect relationship can be determined, this study does demonstrate theoretical effectiveness of a combined manual therapy and perturbation training approach to the treatment of knee osteoarthritis. This approach was associated with significant improvements in pain, function, and balance measures. There were several limitations evident within the study, however the potential positive impact of the interventions provided add to the current literature supporting perturbation and manual therapy techniques for patients suffering from knee osteoarthritis.

Rhon D, et al. Manual physical therapy and perturbation exercises in knee osteoarthritis. Journal of Manual & Manipulative Therapy. 2013; 21(4): 220–228.

Hip Osteoarthritis: Efficacy of Manual Therapy

According to the Clinical Guidelines for Hip Osteoarthritis (OA) published in 2009, the prevalence of hip OA is between 0.4% and 27%. The most common complaint of individuals diagnosed with this debilitating disorder is hip and/or groin pain. Additionally, there is a concomitant decrease in the availability of ROM at the involved hip, which is typically in a capsular pattern (IR > ABD > Flexion). Knowing this information, what can we, as therapists, do for these patients?

The Clinical Guidelines determined that the use of manual therapy has ‘B’ Level Evidence to support its efficacy, which was actually the same level of support that flexibility, strength, and endurance exercises received. In 2005, Hoeksma et al performed a single blind, RCT comparing the effect of manual therapy versus exercise in patients who were diagnosed with osteoarthritis of the hip based on the American College of Rheumatology’s clinical criteria. The manual therapy group received aggressive manual stretching of muscles determined to be tight, long-axis distraction of the involved hip, and traction manipulation in each limited position. Whereas the exercise group received a treatment protocol addressing diminished muscular strength, limited ROM, pain, walking ability, and were provided a HEP. At five weeks, the success rate of the manual therapy group was 81% for the primary outcome measure (6-point likert scale ranging from “much worse” to “complete recovery”), while the exercise group only achieved a success rate of 50%. Additionally, change in the Harris Hip Score, walking speed, pain at rest, pain walking, mean complaint, flexion-extension ROM, ER-IR ROM all favored the manual therapy group. Please take into consideration that the manual therapy group received NO exercise therapy and there were still substantial gains achieved, gains that exceeded those of the exercise group. Also, the effects of the manual therapy treatment lasted for 6 months, which shows the potential long-term benefit of these interventions.

In clinical practice, it almost always makes sense to combine these manual therapy techniques with therapeutic exercise interventions. Smith et al completed a case series looking at the outcomes of a combined manual therapy/exercise treatment approach to patients with OA of the hip. The primary author and his colleagues imployed both thrust and non-thrust mobilizations of the hip depending on the findings of the evaluation and the degree of capsular restriction. All mobilizations/manipulations were performed in the direction of restriction followed by immediate reassessment of PROM and joint mobility to determine changes occurring after administration of the interventions. In addition to the manual techniques, individualized exercise programs were completed by the patients, which included a HEP. At the conclusion of treatment, all 7 patients included in the case series demonstrated substantial improvements and could no longer be classified as having osteoarthritis per the ACR’s clinical classification. The median improvement in total hip ROM was 82° (range, 70°-86°), the median improvement in pain on the Numeric Pain Rating Scale was 5 points (range, 2-7 points), and the median improvement in disability on the Harris Hip Score was 25 points (range, 15-38 points). Unfortunately, there was not a formal follow-up, thus long-term effects could not be determined. However, the primary author was able contact 5 of the 7 patients who gave their subjective report of their symptoms. Patient 1 reported no change in symptoms since D/C, patients 5-7 reported not needing further treatment at 6 months, and patient 4 continued to seek intermittent treatment. So, this does bode well for the long-term effectiveness of the combination of manual therapy and exercise in the treatment of hip OA.

These techniques have been shown to be effective, but what do they actually do? According to a cadaveric study performed by Harding et al, accessory glide of the femoral head on the acetabulum in the anterior-posterior direction does occur and is dependent on force production. Increased force leads to a subsequent increase in the excursion of the femoral head. They found a mean displacement of 0.57 mm at 89N of force and 1.52 mm at 356N of force. An earlier study published by Arvidsson et al determined that it was necessary to apply a force of atleast 400N in order to impart joint separation (0.8-3.0 mm) during the long-axis distraction technique. For comparison, 400N is equal to roughly 90 lbs or 41 kg of pressure. These studies show the ability of a physical therapist to provide forces significant enough to potentially stretch the tissues at and surrounding the hip joint, which should in turn cause a decrease in capsular restriction and an increase in ROM. An additional benefit of providing this manual care is the increase in force production demonstrated by studies published by Makofsky et al and Yerys et al. Both studies performed grade IV mobilizations which resulted in significant increases in peak torque of the hip abductors and gluteus maximus, respectively. The authors of these studies suggest that grade IV mobilization decreases the inhibitory input on the hip musculature. However, at this point, the mechanism behind these findings are purely speculative or theoretical.

Now that we have discussed some of the evidence behind the use of hip mobilizations, let’s take a look at a few common (and effective) techniques…

Long Axis Distraction


1. General mobilization of joint
2. May be initially used to decrease joint pain, decrease muscle spasm, and increase capsular elasticity

(Video Credit: Tennessee State University)

Lateral Distraction


1. General mobilization of joint
2. May be initially used to decrease joint pain, decrease muscle spasm, and increase capsular elasticity

(Video Credit: Chris Arbabian)

Anterior Glide of Femur


1. Restriction in Extension and/or External Rotation

(Video Credit: daney20)

Posterior Glide of Femur


1. Restriction in Flexion and/or Internal Rotation

(Video Credit: daney20)