Gait changes in patients with knee osteoarthritis are replicated by experimental knee pain

Abstract

Objective. Medial knee osteoarthritis (OA) is characterized by pain and associated with abnormal knee moments during walking. The relationship between knee OA pain and gait changes remains to be clarified, and a better understanding of this link could advance the treatment and prevention of disease progression. This study investigated changes in knee moments during walking following experimental knee pain in healthy volunteers, and whether these changes replicated the joint moments observed in medial knee OA patients. Methods. In a crossover study, 34 healthy subjects were tested on 3 different days; gait analyses were conducted before, during, and after pain induced by hypertonic saline injections (0.75 ml) into the infrapatellar fat pad. Isotonic saline and sham injections were used as control conditions. Peak moments in frontal and sagittal planes were analyzed. The results were compared with data from 161 medial knee OA patients. The patients were divided into less severe OA and severe OA categories, which was based on radiographic disease severity of the medial compartment. Results. Experimental knee pain led to reduced peak moments in the frontal and sagittal planes in the healthy subjects, which were similar to the patterns observed in less severe OA patients while walking at the same speed. Conclusion. In healthy subjects, pain was associated with reductions in knee joint moments during walking in a manner similar to less severe knee OA patients. The experimental model may be used to study mechanically-driven knee OA progression and preventive measures against abnormal joint loading in knee OA.

Are Joint Structure and Function Related to Medial Knee OA Pain? A Pilot Study

“…All subjective measurements were correlated (|r| C 0.54) with one another (Table 3), as were most of the objective measurements (|r| C 0.56) except for the peak knee adduction moment which did not correlate with any variable. The lack of correlation of the peak adduction moment to VAS knee pain and other variables was puzzling as it was contrary to the expected outcomes based on several previous reports [29,30,36,37]. However, other researchers also have observed a lack of correlation of knee adduction moment with knee pain, and other variables pertinent in knee OA.…”

Experimental knee joint pain during strength training and muscle strength gain in healthy subjects: A randomized controlled trial

“…It has recently been demonstrated that patients with knee OA who have quadriceps activation failure acquire greater volitional quadriceps activation and muscle strength gain from an intervention aimed at blocking pain sensation centrally in combination with exercise (49). Second, the average pain intensity was 16.2 mm, which is lower than that reported in previous studies (25)(26)(27)36). The time course of experimental IPFP pain shows that maximum pain intensity is reached within 5 minutes, and then gradually declines over the following 10 -12 minutes (23).…”

“…Clinical knee joint pain arises from several structures, including the IPFP, and is a significant source of pain in patients with knee OA (47,48). Furthermore, experimental pain from the IPFP has been shown to change motor functions similar to those identified in knee pathology (22,23,25,26). However, experimental pain does not replicate the long-term aspects of clinical pain, including the psychosocial features.…”

“…Experimental knee pain models make it possible to test the isolated effects of pain on motor functions in healthy volunteers without the influence of confounding disease-related factors (24). It has recently been demonstrated that experimental knee joint pain significantly reduces knee muscle strength (25) as well as causing gait changes comparable to changes seen in knee OA (26). Likewise, experimental knee joint pain induces changes in motor control of the quadriceps (22) and alters the motor unit discharge rate and recruitment strategies (27).…”

Association between skeletal muscle inflammatory markers and walking pattern in people with knee osteoarthritis

“…Pain associated with knee OA has been thought to result in gait modification as an attempt to reduce the load on the affected joint, with studies reporting changes in joint loading as a response to pain relief (22)(23)(24), or pain induction in experimental trials (25,26). Given that an increase in inflammatory markers can promote pain, it may also affect muscle function during gait, leading to different gait strategies to reduce joint load.…”