Walking ability following knee arthroplasty: a prospective pilot study of factors affecting the maximal walking distance in 18 patients before and 6 months after total knee arthroplasty

Long-Term Nonoperative Management is Associated With Lower Mean 9-Year Follow-Up Survival Compared to Total Knee Arthroplasty in Knee Osteoarthritis Patients-Survival Analysis of a Nationwide South Korean Cohort

BACKGROUND

Total knee arthroplasty (TKA) and medications are both considered as a treatment for knee osteoarthritis. However, the impact of the TKA on long-term survival remains controversial. This study aimed to compare 9-year follow-up survival between a TKA group with a nonoperative medication group.

METHODS

From 2007 to 2009, knee osteoarthritis patients were divided into TKA (N = 2,228) and nonoperative medication (N = 76,430) groups, and followed for up to 9 years. The hazard ratio (HR) and subdistribution HR (SHR) were derived from Cox proportional hazards regressions and Fine and Gray analyses, respectively.

RESULTS

The TKA group had a significantly lower adjusted mortality rate (adjusted HR , 0.78, 95% confidence interval [CI], 0.68-0.9) than the nonoperative medication group. Dose-response relationship between medication possession ratio and mortalities for overall (adjusted HR , 1.02; 95% CI, 1.01-1.04) and cardiovascular (CV) death (adjusted SHR, 1.03; 95% CI, 1.01-1.05) was also found. Also, there were significant interactions that indicate stronger protective survival effects of the TKA in several covariates: age >75 years (P = .04 for overall; P = .009 for CV), hypertension (P = .006 for overall), and ischemic heart disease (P = .009 for CV).

CONCLUSIONS

This study suggests that TKA patients had better mean 9-year follow-up survival than the nonoperative medication group after adjusting for baseline differences. For overall death, including CV death, adjusted mortality rates were higher in the medication group and showed a dose-response relationship. Specifically, the protective effect of the TKA for overall or CV deaths was found to be higher for age >75, hypertension, or ischemic heart disease patients.

LEVEL OF EVIDENCE

III.

Physical activity after total knee arthroplasty: A critical review

Total knee arthroplasty (TKA) is the most commonly performed elective surgery in the United States. TKA typically improves functional performance and reduces pain associated with knee osteoarthritis. Little is known about the influence of TKA on overall physical activity levels. Physical activity, defined as “any bodily movement produced by skeletal muscles that results in energy expenditure”, confers many health benefits but typically decreases with endstage osteoarthritis. The purpose of this review is to describe the potential benefits (metabolic, functional, and orthopedic) of physical activity to patients undergoing TKA, present results from recent studies aimed to determine the effect of TKA on physical activity, and discuss potential sources of variability and conflicting results for physical activity outcomes. Several studies utilizing self-reported outcomes indicate that patients perceive themselves to be more physically active after TKA than they were before surgery. Accelerometry-based outcomes indicate that physical activity for patients after TKA remains at or below pre-surgical levels. Several different factors likely contributed to these variable results, including the use of different instruments, duration of follow-up, and characteristics of the subjects studied. Comparison to norms, however, suggests that daily physical activity for patients following TKA may fall short of healthy age-matched controls. We propose that further study of the relationship between TKA and physical activity needs to be performed using accelerometry-based outcome measures at multiple post-surgical time points.

Indoor and Outdoor Mobility following Total Knee Arthroplasty

PURPOSE

To determine the relationship between indoor and outdoor mobility capacity in older adults with unilateral total knee arthroplasty (TKA) and, secondarily, to determine walking intensity in the same population and to compare all outcomes to a control group of older adults without knee pathology.

METHOD

In this cross-sectional study, participants (TKA=16, mean 22.9 (SD 9.7) mo post TKA; control=22) completed indoor walking tests and a 580 m outdoor course that included varying terrain (e.g., curbs, grass, sidewalk) and frequent changes in direction. Walking capacity was assessed using stopwatches, global positioning system watches and accelerometers.

RESULTS

Outdoor walking time was moderately correlated (p<0.05) with the timed up-and-go (TUG) test (r=0.65), stair-climb test (SCT) (r=0.67 ascending, r=0.79 descending), 10 m walk test (10 mWT) (r=0.73), and 6-minute walk test (6 MWT) (r=-0.75). Based on activity counts, walking intensity levels for participants in both groups were moderate (outdoor walk and 6 MWT). There was no significant difference in walking capacity between groups (TUG, SCT, 10 mWT, 6 MWT, outdoor walk).

CONCLUSIONS

Common clinical walking tests are moderately correlated with outdoor mobility. Mobility capacity of individuals post TKA was similar to controls in both indoor and outdoor environments, and participants in both groups achieved moderate physical activity levels with walking.