Quadriceps strength and volitional activation before and after total knee arthroplasty for osteoarthritis

Abstract

I/itroN'uc.tion:Patients with osteoarthritis (OA) of the knee have quadriceps weakness and arthrogenous muscle inhibition (AMI). While total knee arthroplasty (TKA) reliably reduces pain and improves function in patients with knee OA, quadriceps weakness persists after surgery. The purpose of this investigation was to assess contributions of AM1 to quadriceps weakness before and after TKA and to assess the effect of pain on AMI.Mdiod.7: Twenty-eight patients with unilateral, end-stage, primary knee OA were tested an average of 10 days before and 26 days after TKA. The mean age at time of operation was 63 years (range 49-82 years). Measurements on the involved and uninvolved knees were performed using the burst-superimposition technique, where supramaximal electrical stimulation is superimposed on a voluntary contraction. Knee pain during contraction was measured using a numeric rating scale. Rtwtlts:The involved quadriceps were significantly weaker than the uninvolved prior to T K A 0, < 0.05). Quadriceps strength decreased by 60'% (p < 0.001) and activation decreased 17% (p < 0.001 1 after TKA. Changes in muscle activation accounted for 6.5% of the variability in the change in quadriceps strength (Y: = 0.65) ( p < 0.001). Knee pain during muscle contraction accounted for a small, but significant portion of the change in voluntary activation (r' = 0.22) ( p = 0.006).Di.scussio~~: Exercise regimens that emphasize strong muscle contraction and clinical tools that facilitate muscle activation like biofeedback and neuromuscular electrical stimulation may be necessary to reverse the quadriceps activation failure and weakness in the patients with knee OA that worsens after TKA. The failure of current rehabilitation regimens to directly address activation deficits within the first months after surgery may explain the persistent quadriceps weakness in patients after TKA.

The Chitranjan Ranawat Award: The Nonoperated Knee Predicts Function 3 Years after Unilateral Total Knee Arthroplasty

“…Pain plays a role in the ability to use the quadriceps femoris muscles [17,30]; weakness of the quadriceps has been implicated in the development of knee osteoarthrosis [2]. Strength affects function [20]; reduced physical capacity may be both a cause and a consequence of physical impairment and functional limitations [32].…”

Effect of stimulation intensity on assessment of voluntary activation

“…8 In patients, superimposed electrical stimulation is used to assess voluntary activation 9,10 or to assess changes in neural activation due to training or disuse. [11][12][13] With patients however, submaximal muscle stimulation is used frequently to calculate VA, 8,10,14,15 because submaximal currents are better tolerated. 10,16 Muscle stimulation is also easier to apply than nerve stimulation because of the location of the femoral nerve in the femoral triangle.…”

“…In this study, we elaborate on these observations by investigating the effects of stimulation type on actual VA, which in most studies that use superimposed stimulation is the primary parameter of interest. [10][11][12][13][14] It is assumed that there is a linear relationship between voluntary torque of the stimulated muscle and superimposed torque. This indicates that VA is also related linearly to voluntary torque.…”

“…9,[22][23][24] However, if the relationship indeed is curvilinear, VA is overestimated for lower contraction intensities, 2,3,7,25 such as those observed in patients. 2,9,10,12 For maximal contractions VA may also be overestimated, but without a gold standard for the maximal torque capacity (MTC), the extent of overestimation cannot be assessed.…”

Effect of total knee replacement surgery and postoperative 12 month home exercise program on gait parameters

“…Total knee arthroplasty (TKA) is an effective treatment to reduce pain and subjective disability in patients with osteoarthrosis of the knee, but several studies have shown that muscle strength deficiency [1][2][3] and functional limitations may persist for several years after the operation [4][5][6].…”