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

Abstract

The long-term functional abilities of patients after a unilateral total knee arthroplasty (TKA) are influenced by the status of the nonoperated knee at the time of the TKA. We hypothesized that in the 3 years after TKA, the nonoperated limb would become more painful, and the quadriceps muscles would weaken; pain and strength would influence performance on functional testing by 3 years after TKA. Healthy control subjects were tested over the same time interval; we hypothesized the controls would also decline in strength and function over time. Individuals with unilateral knee pain (less than 4/10 on a verbal analog scale) were recruited preoperatively. We tested patients 1, 2, and 3 years after TKA to determine changes in strength, self-report outcome measures, and performance on a stair climbing test and the 6-minute walk test. Control subjects without osteoarthritis were tested twice, 2 years apart. The nonoperated limb of patients with TKA weakened from 1 to 2 years, and further weakened from 2 to 3 years after TKA; by 3 years after TKA, the nonoperated limb was more painful compared to the operated limb. Three years after TKA, nonoperated knee pain contributed 44% of the variability in the 6-minute walk and 33% of the variability in the stair climbing test. Patients with TKA were weaker, slower, and had lower self-report outcome measures compared with control subjects at both time intervals. Control subjects also weakened over time, yet were stable on self-report outcome measures and the 6 minute walk test. Weakening of the quadriceps muscles in all participants represents changes due to ageing; however on average the nonoperated limb weakened over time, possibly representing not only changes resulting from aging, but progression of osteoarthrosis in some patients with unilateral TKA.

Patient-Reported Outcomes After Total Knee Replacement Vary on the Basis of Preoperative Coexisting Disease in the Lumbar Spine and Other Nonoperatively Treated Joints

“…Among studies of musculoskeletal comorbidities, those related to pain in joints other than the operatively treated knee, in particular, have described interesting results. For instance, preoperative pain in the nonoperatively treated knee was associated with poorer knee performance at three years after total knee replacement 4 . Low back pain was shown to predict poorer physical function after primary total knee replacement 5 and was associated with poorer function scores at twelve months and twenty-four months after revision total knee replacement 6 .…”

The Influence of the Contralateral Knee Prior to Knee Arthroplasty on Post-Arthroplasty Function: The Multicenter Osteoarthritis Study

“…predictors of post-arthroplasty function have not examined the impact of contralateral knee symptoms, although a few recent studies have demonstrated that post-arthroplasty factors in the contralateral knee, such as strength 7 and pain 8 , are associated with post-arthroplasty function. As some of the effects of postarthroplasty contralateral knee symptoms on function may be due to contralateral impairments that developed as a consequence of surgery, increasing the demand on the contralateral knee, it is important to study both the pre-arthroplasty status and the post-arthroplasty status of the contralateral knee.…”

Do Patients Achieve Normal Gait Patterns 3 Years After Total Knee Arthroplasty?

“…7 This loss of strength is exemplified by a reduction in the contribution of the knee extensor moment during loading response in the nonoperated limb by 1 year after TKA. 32 As a result, bilateral strength deficits may underlie the gait abnormalities in patients after TKA compared to age-matched healthy individuals.…”