title: Is knee joint proprioception worse in the arthritic knee versus the unaffected knee in unilateral knee osteoarthritis?
abstract: OBJECTIVE
  Neuromuscular joint protection requires proprioceptive input and motor output. Impairment of proprioception in knee osteoarthritis (OA) may contribute to, and/or result from, the disease. If this impairment was exclusively a local result of OA, a between-knee difference would be expected in patients with unilateral OA (UOA). To explore causal directions, 2 hypotheses were tested: 1) proprioception is worse in UOA patients versus elderly controls; 2) proprioception is worse in the arthritic knee versus the unaffected knee in UOA patients.
  
  
  METHODS
  Twenty-eight UOA patients (Kellgren-Lawrence grade > or =2 in 1 knee and <2 in the other knee) and 29 elderly controls were enrolled. The unaffected knee of each UOA patient and both knees of the elderly controls were required to meet symptom, examination, and radiographic criteria. Proprioception (detection threshold of joint displacement after slow, passive, automated knee motion), body mass index, pain, functional status, range of motion, and laxity were measured.
  
  
  RESULTS
  UOA patients had worse proprioception than did elderly controls, in either knee. A between-knee difference was not found in UOA patients.
  
  
  CONCLUSIONS
  Impaired proprioception is not exclusively a local result of disease in knee OA. The relative importance of impaired proprioception in the development and progression of knee OA will require longitudinal study.
authors.affiliation: Northwestern University, Chicago, Illinois 60611, USA.
authors.forename: L
authors.initials: L
authors.lastname: Sharma
authors.forename: Y C
authors.initials: YC
authors.lastname: Pai
authors.forename: K
authors.initials: K
authors.lastname: Holtkamp
authors.forename: W Z
authors.initials: WZ
authors.lastname: Rymer
mesh_terms: D000368:Aged; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011434:Proprioception / Q000502:physiology*; D011859:Radiography