title: Alterations in neuromuscular patterns between pre and one-year post-total knee arthroplasty.
abstract: BACKGROUND
  Total knee arthroplasty is a common treatment for severe knee osteoarthritis. Objective measures are needed to evaluate the effect of arthroplasty surgery on function and joint loading, in particular given the rise in younger adults receiving this intervention. The objective was to compare neuromuscular activation patterns of the knee musculature during level walking one-week prior to and one-year following total knee arthroplasty.
  
  
  METHODS
  Surface electromyograms from seven periarticular muscles were recorded from 43 patients with severe medial compartment knee osteoarthritis during walking one-week prior to and one-year following total knee arthroplasty. Principal component analysis extracted patterns from the electromyographic waveforms and assigned scores for these patterns, which were statistically compared between test times and between medial and lateral sites within a muscle group.
  
  
  RESULTS
  Significantly lower overall activation amplitudes were found for the quadriceps and hamstrings, with decreased activity during mid-late stance following surgery. Significant increases in gastrocnemius activity were found late stance, along with altered waveform shapes.
  
  
  CONCLUSIONS
  In general, the post-surgical changes moved toward more typical asymptomatic patterns, supporting improved neuromuscular strategies during walking. Given that improvements would not be expected to occur naturally in severe osteoarthritic knees the positive changes in neuromuscular characteristics during specific phases of the gait cycle can be explained in part by the altered mechanical environment and reduction in pain from the surgical intervention. These objective findings are directly relevant to the joint loading environment and can be valuable for evaluating surgical techniques, different prostheses and pre-post surgical management.
authors: School of Physiotherapy, Dalhousie University, Halifax, Nova Scotia, Canada. clk@dal.ca
authors: Cheryl L
authors: CL
authors: Hubley-Kozey
authors: Gillian L
authors: GL
authors: Hatfield
authors: Janie L
authors: JL
authors: Astephen Wilson
authors: Michael J
authors: MJ
authors: Dunbar
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000628:therapy; D011184:Postoperative Period; D025341:Principal Component Analysis; D052097:Quadriceps Muscle / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome