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

Study Design

Prospective, observational cohort study.

Subjects

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)

Methods

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.

Results

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.

Limitations

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.

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