Use of a Squatting Movement as a Clinical Marker of Function After Total Knee Arthroplasty

and Department of Physical Therapy, Miller School of Medicine, University of Miami, Florida (M. Wong).
American journal of physical medicine & rehabilitation / Association of Academic Physiatrists (Impact Factor: 2.01). 01/2013; 92(1):53-60. DOI: 10.1097/PHM.0b013e318269d8d0
Source: PubMed

ABSTRACT The aims of this study were to evaluate weight bearing during standing and 30- and 60-degree squats approximately 1 wk and 2 mos after surgery and determine whether weight bearing during squatting could be a better clinical marker than standing for identifying perceived functional limitation approximately 1 wk after surgery. A further objective was to determine whether age, body mass index, and number of outpatient visits over the course of rehabilitation predicted weight bearing during a squat approximately 2 mos after surgery.
The percentage of body weight placed over both limbs during stand and 30- and 60-degree squats in 38 patients (25 women and 13 men) who had primary unilateral knee arthroplasty was determined. An asymmetry index would be used as a marker that could discriminate between those who perceived at least moderate difficulty with functional tasks and those who perceived only slight or no difficulty with functional activities based on the physical function dimension of the Western Ontario McMaster Universities Osteoarthritis index approximately 1 wk after surgery. Stepwise regression was conducted to determine whether clinical characteristics predicted weight-bearing asymmetry at discharge.
At initial visit (first observation), and compared with the uninvolved side, individuals placed significantly less body weight over the involved or operated limb for stand and 30- and 60-degree squats (P < 0.0001). Results were similar at last rehabilitation visit (second observation). Identifying at least moderate self-reported difficulty with functional tasks based on the receiver operator characteristic curve for the asymmetry index for the stand position was 0.64, whereas for the 30- and 60-degree squats, the area under the curve was 0.81 and 0.89, respectively. At discharge from rehabilitation, there was a moderate to good direct relationship (r = 0.70) between the number of rehabilitation visits completed and the weight-bearing asymmetry index for the 60-degree squat.
On the first outpatient visit, individuals who had primary unilateral knee arthroplasty placed more body weight over the uninvolved side for the three weight-bearing positions. With high probability, the asymmetry index for both squatting angles identified perceived functional difficulty. As rehabilitation visits increased, there was a direct association to improved interlimb weight-bearing symmetry when squatting to 60 degrees.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Factors that predict functional recovery in the first few days following hip fracture and that may facilitate discharge to the home directly from the acute care setting have not been identified. This study investigated the attainment of key functional milestones by patients and discharge status from an acute care hospital following hip fracture. Subjects were 162 community-based individuals (59 men, 103 women) aged 60 years or older who were admitted to an acute care hospital following unilateral hip fracture. Data on personal, medical surgical, hospital course, and acute rehabilitation factors as well as functional status and placement at the time of discharge were collected. Adjusted odds ratios were calculated to determine predictors of independence in seven types of transfers and ambulation activities and discharge directly to the home. Subjects who ambulated independently prior to fracture, stayed longer in the acute care setting, and received physical therapy on average more than once a day had improved odds of regaining independence in bed mobility, transfers, and ambulation. Subjects who regained independence and received physical therapy on average more than once a day had improved odds of discharge directly to the home from the acute care setting. Increasing age and postoperative complications reduced the odds of discharge directly home. A substantial proportion of patients with hip fracture achieve independence in bed mobility and transfers and in ambulation with a walker during the early postoperative phase, although few progress to a higher level during a short-term stay in the acute care setting. Frequency of physical therapy, among other factors, appears to improve the odds of regaining functional independence and discharge directly to the home from the acute care setting.
    Physical Therapy 09/1996; 76(8):818-26. · 3.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Prospective study with repeated measures. The overall goal of this investigation was to describe the time course of recovery of impairments and function after total knee arthroplasty (TKA), as well as to provide direction for rehabilitation efforts. We hypothesized that quadriceps strength would be more strongly correlated with functional performance than knee flexion range of motion (ROM) or pain at all time periods studied before and after TKA. TKA is a very common surgery, but very little is known regarding the influence of impairments on functional limitations in this population. Forty subjects who underwent unilateral TKA followed by rehabilitation, including 6 weeks of outpatient physical therapy, were studied. Testing occurred at 5 time periods: preoperatively, and at 1, 2, 3, and 6 months after surgery. Test measures included quadriceps strength, knee ROM, timed up-and-go test, timed stair-climbing test, bodily pain, and general health and knee function questionnaires. Subjects experienced significant worsening of knee ROM, quadriceps strength, and performance on functional tests 1 month after surgery. Quadriceps strength went through the greatest decline of all the physical measures assessed and never matched the strength of the uninvolved limb. All measures underwent significant improvements following the 1-month test. Quadriceps strength was the most highly correlated measure associated with functional performance at all testing sessions. Functional measures underwent an expected decline early after TKA, but recovery was more rapid than anticipated and long-term outcomes were better than previously reported in the literature. The high correlation between quadriceps strength and functional performance suggests that improved postoperative quadriceps strengthening could be important to enhance the potential benefits of TKA.
    Journal of Orthopaedic and Sports Physical Therapy 08/2005; 35(7):424-36. DOI:10.2519/jospt.2005.35.7.424 · 2.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Total knee arthroplasty (TKA) successfully reduces pain, but has not achieved comparable improvements in function. We hypothesized that quadriceps strength affects performance by altering loading and movement patterns during functional tasks. Fourteen subjects with isolated, unilateral TKA were tested three months after surgery. Quadriceps strength was assessed isometrically and kinematics, kinetics, and EMG were collected during level walking and sit-to-stand (STS). Function was assessed using the timed up and go test (TUG), stair climbing test (SCT), and the 6 min walk test (6MW). Functional performance was significantly related to the quadriceps strength of both legs, but was more strongly related to the uninvolved strength (involved rho=-0.43 with TUG; -0.65 with SCT; 0.64 with 6MW) (uninvolved rho=-0.63 with TUG; -0.68 with SCT; 0.77 with 6MW). During STS, subjects shifted weight away from the operated limb (p<0.01). Quadriceps muscle activity and the extension moments at the knee and hip were smaller in the involved compared to the uninvolved (p<0.05). The amount of asymmetry in knee excursion during weight acceptance in gait, the asymmetry in weight bearing from sit-to-stand, and the uninvolved hip extension moment during STS were related to the amount of asymmetry in quadriceps strength (rho>0.56, p<0.05). Quadriceps weakness in patients with TKA has a substantial impact on the movement patterns and performance of the knee during functionally important tasks.
    Journal of Orthopaedic Research 10/2005; 23(5):1083-90. DOI:10.1016/j.orthres.2005.01.021 · 2.97 Impact Factor
Show more