Joint mobilization associated with improved PPTs in conditioned pain modulation in knee OA

Study Type: Therapy
OE Level of Evidence: 2
Journal Level of Evidence: N/A
29 out of 40 patients with osteoarthritis of the knee exhibited impaired conditioned pain modulation (CPM) and were randomized to one of two interventions (with cross-over thereafter) for the purpose of examining physiotherapeutic effects on knee pain, pressure pain thresholds, and vibration perception thresholds: (1) oscillatory joint mobilization or (2) cutaneous input (control -light placement of both hands on the subject's knee). Results demonstrated that Please login to view the rest of this report. Please login to view the rest of this report.
Funding: Non-Industry funded
Sponsor: Orthopaedic Section of the American Physical Therapy Association
Conflicts: None disclosed
Why was this study needed now?
Patients with osteoarthritis (OA) of the knee often cite pain as the main contributor to impaired mobility. Aberrant pain mechanisms that may contribute to chronic knee OA pain have been identified and include hyperexcitability of the central nociceptive pathways and defective descending pain inhibition; imbalance in these processes is associated with chronic pain and disability. Analysis of pain inhibition can be accomplished with conditioned pain modulation (CPM), which involves the inhibition of pain through application of a noxious stimulant at a remote site. Recent evidence has suggested that a patient’s inability to respond to CPM is predictive of chronic pain. Therefore, identifying interventions that promote descending pain inhibition is important for developing strategies to manage chronic pain. Joint mobilization is a common physiotherapeutic treatment in the management of painful joint conditions and clinical trials support its use in rehabilitation of knee OA, however, its effect on pain inhibitory mechanisms has yet to be investigated. Thus, the current study was conducted.
What was the principal research question?
For patients with osteoarthritis of the knee exhibiting impaired conditioned pain modulation (CPM), did oscillatory joint mobilization result in enhanced pain inhibition? A secondary objective was to determine the effect of joint mobilization on impaired vibration perception. Previous studies have suggested that sensory function may be inhibited by pain. It was postulated that joint mobilization as an intervention may normalize sensory impairment in persons with chronic knee OA pain.
Population: 40 patients with unilateral or bilateral osteoarthritis of the tibiofemoral joint, demonstrating >/3 on the Kellgren-Lawrence scale for radiographic OA and impaired CPM were included in this study. 29 of these individuals demonstrated impaired pain modulation. Confirmation of impaired CPM was performed using the upper extremity submaximal-effort tourniquet test. Prior to outcome testing, all patients were acclimated to a room temperature of 70 degrees Fahrenheit and were provided with vibration perception and pressure/pain procedure education. All patients were instructed to refrain from anti-inflammatory or pain medication use for the 24-hour period prior to testing to ensure normalized activity levels (n=29, mean age= 59.41+/-8.33, 13M/16F).
Intervention: Joint Mobilization group: the intervention was performed by gliding of the tibia forward and back along the femur in an oscillatory manner within a pain-free and slight tissue resistance range. Two applications, each lasting 3 minutes, were separated by a 30-second interval. As a part of the crossover design, the cutaneous input was performed in the following session.
Comparison: Cutaneous Input group: The intervention was performed by light placement of both hands on the subject's knee. Two applications, each lasting 3 minutes, were separated by a 30-second interval. As a part of the crossover design, the joint mobilization intervention was performed in the following session.
Outcomes: Outcomes of interest included resting pain with a visual analogue scale (VAS), vibration perception threshold with a biothesiometer at the medial femoral condyle, and pressure pain threshold between the first and second metacarpophalangeal joints on the contralateral side.
Methods: RCT: cross-over study, assessor-blinded, single-centre
Time: Outcomes were evaluated at baseline and after completion of CPM testing (two weeks).
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What should I remember most?
How will this affect the care of my patients?
The authors responsible for this critical appraisal and ACE Report indicate no potential conflicts of interest relating to the content in the original publication.
Alfredo Axtmayer
March 5, 2017
Orthopaedic Surgeon - United States
Non randomized study
Dr. Ortho Evidence
March 6, 2017
Other - Canada
Thank you for your comment. This trial used a randomized crossover design to investigate the effects of joint mobilization on patients with impaired conditioned pain modulation. Patients identified with impaired conditioned pain modulation were included and randomized to the type of treatment they received first; knee joint modulation or manual cutaneous input. Outcome measures were assessed after the initial treatment which was then followed by a one week washout period. Patients then returned and completed treatment using the other intervention and outcome measures were assessed.