Jennifer E. Stevens-Lapsley

Outcomes Before and After Total Knee Arthroplasty Compared to Healthy Adults

STUDY DESIGN Prospective cohort study. OBJECTIVES To measure changes in muscle strength, range of motion, and function from 2 weeks before to 6 months after total knee arthroplasty (TKA) and compare outcomes with data from a control group consisting of healthy adults. BACKGROUND Total knee arthroplasty successfully alleviates pain from knee osteoarthritis, but deficits in function can persist long term. How impairments and functional limitations change over the first 6 months after TKA, compared to data from healthy adults, has not been well reported in the literature. METHODS Twenty-four patients who underwent a primary unilateral TKA were compared to healthy adults (n = 17). All patients participated in a standardized rehabilitation program following surgery. Isometric quadriceps torque was assessed using an electromechanical dynamometer. Range of motion was measured actively and passively. Functional performance was assessed using the stair-climbing test, timed up-and-go test, 6-minute walk test, and single-limb stance time. Patients underwent testing at 2 weeks preoperatively and at 1, 3, and 6 months postoperatively. RESULTS Compared to healthy older adults, patients performed significantly worse at all times for all measures (P<.05), except for single-limb stance time at 6 months (P>.05). One month postoperatively, patients experienced significant losses from preoperative levels in all outcomes. Patients recovered to preoperative levels by 6 months postoperatively on all measures, except knee flexion range of motion, but still exhibited the same extent of limitation they did prior to surgery. CONCLUSION The persistent impairments and functional limitations 6 months after TKA with standard rehabilitation suggest that more intensive therapeutic approaches may be necessary to restore function of patients following TKA to the levels of healthy adults.

Early Neuromuscular Electrical Stimulation to Improve Quadriceps Muscle Strength After Total Knee Arthroplasty: A Randomized Controlled Trial

Background The recovery of quadriceps muscle force and function after total knee arthroplasty (TKA) is suboptimal, which predisposes patients to disability with increasing age. Objective The purpose of this investigation was to evaluate the efficacy of quadriceps muscle neuromuscular electrical stimulation (NMES), initiated 48 hours after TKA, as an adjunct to standard rehabilitation. Design This was a prospective, longitudinal randomized controlled trial. Methods Sixty-six patients, aged 50 to 85 years and planning a primary unilateral TKA, were randomly assigned to receive either standard rehabilitation (control) or standard rehabilitation plus NMES applied to the quadriceps muscle (initiated 48 hours after surgery). The NMES was applied twice per day at the maximum tolerable intensity for 15 contractions. Data for muscle strength, functional performance, and self-report measures were obtained before surgery and 3.5, 6.5, 13, 26, and 52 weeks after TKA. Results At 3.5 weeks after TKA, significant improvements with NMES were found for quadriceps and hamstring muscle strength, functional performance, and knee extension active range of motion. At 52 weeks, the differences between groups were attenuated, but improvements with NMES were still significant for quadriceps and hamstring muscle strength, functional performance, and some self-report measures. Limitations Treatment volume was not matched for both study arms; NMES was added to the standard of care treatment. Furthermore, testers were not blinded during testing, but used standardized scripts to avoid bias. Finally, some patients reached the maximum stimulator output during at least one treatment session and may have tolerated more stimulation. Conclusions The early addition of NMES effectively attenuated loss of quadriceps muscle strength and improved functional performance following TKA. The effects were most pronounced and clinically meaningful within the first month after surgery, but persisted through 1 year after surgery.

Slower walking speed forecasts increased postoperative morbidity and 1-year mortality across surgical specialties.

Objective: The purpose of this study was to determine the relationship between the Timed Up and Go test and postoperative morbidity and 1-year mortality, and to compare the Timed Up and Go to the standard-of-care surgical risk calculators for prediction of postoperative complications. Methods: In this prospective cohort study, patients 65 years and older undergoing elective colorectal and cardiac operations with a minimum of 1-year follow-up were included. The Timed Up and Go test was performed preoperatively. This timed test starts with the subject standing from a chair, walking 10 feet, returning to the chair, and ends after the subject sits. Timed Up and Go results were grouped as fast ⩽ 10 seconds, intermediate = 11–14 seconds, and slow ≥ 15 seconds. Receiver operating characteristic curves were used to compare the 3 Timed Up and Go groups to current standard-of-care surgical risk calculators at forecasting postoperative complications. Results: This study included 272 subjects (mean age of 74 ± 6 years). Slower Timed Up and Go was associated with increased postoperative complications after colorectal (fast 13%, intermediate 29%, and slow 77%; P < 0.001) and cardiac (fast 11%, intermediate 26%, and slow 52%; P < 0.001) operations. Slower Timed Up and Go was associated with increased 1-year mortality following both colorectal (fast 3%, intermediate 10%, and slow 31%; P = 0.006) and cardiac (fast 2%, intermediate 3%, and slow 12%; P = 0.039) operations. Receiver operating characteristic area under curve of the Timed Up and Go and the risk calculators for the colorectal group was 0.775 (95% CI: 0.670–0.880) and 0.554 (95% CI: 0.499–0.609), and for the cardiac group was 0.684 (95% CI: 0.603–0.766) and 0.552 (95% CI: 0.477–0.626). Conclusions: Slower Timed Up and Go forecasted increased postoperative complications and 1-year mortality across surgical specialties. Regardless of operation performed, the Timed Up and Go compared favorably to the more complex risk calculators at forecasting postoperative complications.

Comparison of Self-Reported Knee Injury and Osteoarthritis Outcome Score to Performance Measures in Patients After Total Knee Arthroplasty

To characterize patient outcomes after total knee arthroplasty (TKA) by (1) examining changes in self‐report measures (Knee Injury and Osteoarthritis Outcome Score [KOOS]) and performance measures over the first 6 months after TKA, (2) evaluating correlations between changes in KOOS self‐report function (activities of daily living [ADL] subscale) and functional performance (6‐minute walk [6MW]), and (3) exploring how changes in pain correlate with KOOS ADL and 6MW outcomes.

Continuous peripheral nerve blocks: is local anesthetic dose the only factor, or do concentration and volume influence infusion effects as well?

Background:The main determinant of continuous peripheral nerve block effects—local anesthetic concentration and volume or simply total drug dose—remains unknown. Methods:We compared two different concentrations and basal rates of ropivacaine—but at equivalent total doses—for continuous posterior lumbar plexus blocks after hip arthroplasty. Preoperatively, a psoas compartment perineural catheter was inserted. Postoperatively, patients were randomly assigned to receive perineural ropivacaine of either 0.1% (basal 12 ml/h, bolus 4 ml) or 0.4% (basal 3 ml/h, bolus 1 ml) for at least 48 h. Therefore, both groups received 12 mg of ropivacaine each hour with a possible addition of 4 mg every 30 min via a patient-controlled bolus dose. The primary endpoint was the difference in maximum voluntary isometric contraction (MVIC) of the ipsilateral quadriceps the morning after surgery, compared with the preoperative MVIC, expressed as a percentage of the preoperative MVIC. Secondary endpoints included hip adductor and hip flexor MVIC, sensory levels in the femoral nerve distribution, hip range-of-motion, ambulatory ability, pain scores, and ropivacaine consumption. Results:Quadriceps MVIC for patients receiving 0.1% ropivacaine (n = 26) declined by a mean (SE) of 64.1% (6.4) versus 68.0% (5.4) for patients receiving 0.4% ropivacaine (n = 24) between the preoperative period and the day after surgery (95% CI for group difference: −8.0–14.4%; P = 0.70). Similarly, the groups were found to be equivalent with respect to secondary endpoints. Conclusions:For continuous posterior lumbar plexus blocks, local anesthetic concentration and volume do not influence nerve block characteristics, suggesting that local anesthetic dose (mass) is the primary determinant of perineural infusion effects.

Early High-Intensity Rehabilitation Following Total Knee Arthroplasty Improves Outcomes

STUDY DESIGN Prospective cohort study with an age-matched and sex-matched control group. OBJECTIVES To assess the clinical outcomes of a high-intensity rehabilitation program (HI) compared to those of a group of age-matched and sex-matched controls who underwent a lower intensity rehabilitation program. BACKGROUND Total knee arthroplasty (TKA) successfully alleviates pain from knee osteoarthritis; but deficits in function can persist long term. Despite these well-known deficits, there is little evidence supporting the use of rehabilitation interventions following TKA. METHODS Eight patients, who participated in the HI program, were compared to 8 age-matched and sex-matched patients who participated in a lower intensity rehabilitation program (control group). Patients were assessed preoperatively, and at 3.5, 6.5, 12, 26, and 52 weeks postoperatively. Assessment of patients included measures of pain, range of motion (ROM), functional performance, and quadriceps strength and activation. RESULTS There were no differences in knee ROM and pain between the HI and control groups at any postoperative time point. At the 3.5-week and 12-week (end of rehabilitation) time points, the HI group had better functional performance and quadriceps strength compared to the control group (P<.05). At the 52-week time point, the HI group continued to demonstrate better functional performance compared to the control group (P<.05), along with greater quadriceps strength (P = .08). CONCLUSION A HI program leads to better short- and long-term strength and functional performance outcomes compared to a lower intensity rehabilitation program. The HI program did not impair knee ROM and did not result in any musculoskeletal injuries in this small group of patients. LEVEL OF EVIDENCE Therapy, level 2b.

Weight-bearing asymmetry in relation to measures of impairment and functional mobility for people with knee osteoarthritis.

OBJECTIVES To compare weight-bearing asymmetry (WBA) for people with unilateral knee osteoarthritis (OA) with that for healthy adults of similar age. In addition, associations between WBA and clinical measures of knee impairment and functional mobility were evaluated. DESIGN Cross-sectional design with age-matched control (CTL) group. SETTING Clinical research laboratory. PARTICIPANTS People with end-stage unilateral knee OA (n=50) (OA group) and healthy people (n=17) (CTL group) were enrolled in the study (N=67). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES WBA during a Five Times Sit-to-Stand Test (FTSST) based on average vertical ground reaction force under each foot, self-reported knee pain assessed using a Numerical Pain Rating Scale, knee extensor strength asymmetry based on peak isometric knee extension torque, knee motion asymmetry based on maximum passive knee extension and flexion angles, FTSST time, six-minute walk test distance, and Stair Climbing Test time. RESULTS The OA group demonstrated greater WBA than the CTL group during transitions between sitting and standing as measured by an absolute symmetry index (P=.015). No correlation was found between WBA and knee motion asymmetry, but comparisons of WBA with all the other outcome variables indicated fair relationships (range, r=.29-.44). CONCLUSIONS Weight-bearing asymmetry during transitions between sitting and standing can serve as a clinically relevant measure related to both knee impairment and functional mobility for people with unilateral knee OA.

Muscle Strength and Functional Recovery During the First Year After THA

BackgroundPatients undergoing total hip arthroplasty (THA) often are satisfied with the decrease in pain and improvement in function they achieve after surgery. Even so, strength and functional performance deficits persist after recovery, but these remain poorly characterized; knowledge about any ongoing strength or functional deficits may allow therapists to design rehabilitation programs to optimize recovery after THA.Questions/purposesThe purposes of this study were to (1) evaluate postoperative muscle strength, function, and quality of life during the first year after THA; and (2) compare strength and function in patients 1 year after THA with a cohort of healthy peers.MethodsTwenty-six patients undergoing THA were assessed 1, 3, 6, and 12 months postoperatively, and 19 adults with no hip pathology were tested as a control group. Isometric muscle strength (hip flexors, extensors, abductors, knee extensors, and flexors), functional performance (stair climbing, five times sit-to-stand, timed-up-and-go, 6-minute walk, and single-limb stance tests), and self-reported function (Hip Disability and Osteoarthritis Score, SF-36, and UCLA activity score) were compared.ResultsOne month after THA, patients had 15% less hip flexor and extensor torque, 26% less abductor torque, 14% less knee extensor and flexor torque, and worse performance on the stair climbing, timed-up-and-go, single-limb stance, and 6-minute walk. Compared with healthy adults, patients 12 months after THA had 17% less knee extensor and 23% less knee flexor torque; however, the functional testing (including stair climbing, five times sit-to-stand, and the 6-minute walk) showed no significant differences with the patient numbers available between individuals undergoing THA and healthy control subjects. SF-36 Physical Component Scores, although significantly improved from preoperative levels, were significantly worse than healthy adults 1 year after THA (p < 0.01).ConclusionsPatients experience early postoperative strength losses and decreased functional capacity after THA, yet strength deficits may persist after recovery. This may suggest that rehabilitation may be most effective in the first month after surgery.Level of EvidenceLevel II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Relationship Between Intensity of Quadriceps Muscle Neuromuscular Electrical Stimulation and Strength Recovery After Total Knee Arthroplasty

Background Neuromuscular electrical stimulation (NMES) can facilitate the recovery of quadriceps muscle strength after total knee arthroplasty (TKA), yet the optimal intensity (dosage) of NMES and its effect on strength after TKA have yet to be determined. Objective The primary objective of this study was to determine whether the intensity of NMES application was related to the recovery of quadriceps muscle strength early after TKA. A secondary objective was to quantify quadriceps muscle fatigue and activation immediately after NMES to guide decisions about the timing of NMES during rehabilitation sessions. Design This study was an observational experimental investigation. Methods Data were collected from 30 people who were 50 to 85 years of age and who received NMES after TKA. These people participated in a randomized controlled trial in which they received either standard rehabilitation or standard rehabilitation plus NMES to the quadriceps muscle to mitigate strength loss. For the NMES intervention group, NMES was applied 2 times per day at the maximal tolerable intensity for 15 contractions beginning 48 hours after surgery over the first 6 weeks after TKA. Neuromuscular electrical stimulation training intensity and quadriceps muscle strength and activation were assessed before surgery and 3.5 and 6.5 weeks after TKA. Results At 3.5 weeks, there was a significant association between NMES training intensity and a change in quadriceps muscle strength (R2=.68) and activation (R2=.22). At 6.5 weeks, NMES training intensity was related to a change in strength (R2=.25) but not to a change in activation (R2=.00). Furthermore, quadriceps muscle fatigue occurred during NMES sessions at 3.5 and 6.5 weeks, whereas quadriceps muscle activation did not change. Limitations Some participants reached the maximal stimulator output during at least 1 treatment session and might have tolerated more stimulation. Conclusions Higher NMES training intensities were associated with greater quadriceps muscle strength and activation after TKA.

Impact of Body Mass Index on Functional Performance After Total Knee Arthroplasty

The purpose of this investigation was to determine whether functional performance and self-report outcomes are related to body mass index (BMI) after total knee arthroplasty (TKA). We hypothesized that higher BMIs would negatively affect functional performance as assessed by the timed up-and-go test, stair climbing test, 6-minute walk test, and self-report questionnaires. A total of 140 patients with BMIs ranging from 21.2 to 40.0 kg/m2 were followed over the first 6 months after unilateral TKA. Hierarchical linear regression was used to evaluate the impact of BMI on functional performance at 1, 3, and 6 months after TKA, while taking into account preoperative functional performance. There were no meaningful relationships between BMI and functional performance in the subacute (1 and 3 months) and intermediate (6-month) stages of recovery.