G. Kelley Fitzgerald

The Relationship Between Passive Joint Laxity and Functional Outcome After Anterior Cruciate Ligament Injury

Twenty patients with anterior cruciate ligament-defi cient knees were studied. Ten patients returned to all sports activities (compensators) and 10 patients were not improved with nonoperative management and re quired surgical stabilization (noncompensators). Joint laxity was measured using a KT-2000 arthrometer (manual maximum Lachman). Subjects completed a Lysholm questionnaire and Knee Outcome Score. The International Knee Documentation Committee form was also completed. Patients also rated their knee function on a scale of 1 to 100. There was no difference in level and frequency of athletic activity between the two groups before their anterior cruciate ligament inju ries as determined by the knee outcome score. The compensator group had a mean side-to-side difference of 3.25 mm at 89 N and the noncompensators had a mean difference of 3 mm preoperatively. Manual max imum tests gave side-to-side differences of 6.7 mm for the compensators and 6 mm for the noncompensators. There were no differences in laxity measures between groups. The correlation between knee outcome scores and side-to-side laxity measurements were not signif icant. Measurements of anterior laxity in anterior cru ciate ligament-deficient patients were not correlated with measures of functional outcome used in this study. Functional outcome measurements that are par tially based on joint laxity measures, such as the Inter national Knee Documentation Committee form, may artificially overestimate the disability after anterior cru ciate ligament rupture.

Relationships of Fear, Anxiety, and Depression With Physical Function in Patients With Knee Osteoarthritis

OBJECTIVES To explore whether the psychologic variables anxiety, depression, and fear-avoidance beliefs, and interactions between these variables, are associated with physical function in patients with knee osteoarthritis (OA). We hypothesized lower levels of function would be related to higher anxiety, higher depression, and higher fear-avoidance beliefs, and that high levels of 2 of these factors simultaneously might interact to have a greater adverse effect on physical function. DESIGN Cross-sectional, correlational design. SETTING Institutional practice. PARTICIPANTS Subjects included patients with knee OA (N=182; age, mean +/- SD, 63.9+/-8.8y; 122 women). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Self-report measures of function included the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index, the Lower Extremity Function Scale (LEFS), and the Knee Outcome Survey-Activity of Daily Living Scale. The Get Up and Go test was used as a physical performance measure of function. Self-report measures for psychologic variables included the Beck Anxiety Inventory, the Center for Epidemiological Studies Depression Scale, and the Fear Avoidance Belief Questionnaire-Physical Activity Scale modified for the knee. RESULTS Higher anxiety was related to poorer function on the WOMAC physical function. Both high anxiety and fear-avoidance beliefs were related to poorer function on the LEFS and Knee Outcome Survey-Activity of Daily Living Scale. There was no association between the psychologic variables and the Get Up and Go test. The anxiety x depression interaction was associated with the LEFS. CONCLUSIONS Anxiety and fear-avoidance beliefs are associated with self-report measures of function in patients with knee OA. Depression may influence scores on the LEFS under conditions of low anxiety.

Biomechanical evidence supporting a differential response to acute ACL injury

OBJECTIVE To describe movement patterns in people with complete anterior cruciate ligament rupture objectively identified as good candidates for non-operative management of the injury. DESIGN Involved side kinematics and kinetics were compared to the uninvolved side and to uninjured subjects. BACKGROUND High-level athletes with anterior cruciate ligament rupture and poor dynamic stability (non-copers) have movement alterations, including less knee flexion and a decreased internal knee extensor moment during loading response, that are not seen in those with excellent knee stability (copers). Our screening exam can identify people with good rehabilitation potential for non-operative management of anterior cruciate ligament injury (potential copers), but the movement strategies of these individuals are unknown. METHODS Sagittal plane kinematics and kinetics during the stance phase of walking and jogging were collected from 11 subjects who had an acute anterior cruciate ligament rupture and met the criteria of the screening exam, and were compared to 10 uninjured subjects, who we studied previously. Variables were those in which non-copers differed from uninjured subjects. RESULTS The potential copers flexed their involved knee less than uninjured subjects and their uninvolved side during walking. Potential copers, compared to uninjured subjects, also had a lower vertical ground reaction force during loading response, a lower knee support moment, and an increased ankle support moment during walking. In jogging, the involved knee angle at initial contact was more extended compared to uninjured subjects, and the amount of knee flexion was less than the uninvolved side. No differences in kinetics were present during jogging. CONCLUSIONS This study provides evidence that the potential copers identified by the screening examination have movement patterns that are consistent with people who have more knee stability than non-copers. RELEVANCE Although potential copers have developed some characteristics of a successful stabilization strategy, the presence of kinematic alterations indicates that they may benefit from training programs designed to enhance dynamic knee stability.

A Balance Exercise Program Appears to Improve Function for Patients With Total Knee Arthroplasty: A Randomized Clinical Trial

Background Patients with total knee arthroplasty (TKA) have impaired balance and movement control. Exercise interventions have not targeted these impairments in this population. Objectives The purposes of this study were: (1) to determine the feasibility of applying a balance exercise program in patients with TKA, (2) to investigate whether a functional training (FT) program supplemented with a balance exercise program (FT+B program) could improve physical function compared with an FT program alone in a small group of individuals with TKA, and (3) to test the methods and calculate sample size for a future randomized trial with a larger study sample. Design This study was a double-blind, pilot randomized clinical trial. Setting The study was conducted in the clinical laboratory of an academic center. Participants The participants were 43 individuals (30 female, 13 male; mean age=68 years, SD=8) who underwent TKA 2 to 6 months prior to the study. Interventions The interventions were 6 weeks (12 sessions) of a supervised FT or FT+B program, followed by a 4-month home exercise program. Measurements Feasibility measures included pain, stiffness, adherence, and attrition. The primary outcome measure was a battery of physical performance tests: self-selected gait speed, chair rise test, and single-leg stance time. Secondary outcome measures were the Western Ontario and McMaster Universities Osteoarthritis Index and the Lower Extremity Functional Scale. Results Feasibility of the balance training in people with TKA was supported by high exercise adherence, a relatively low dropout rate, and no adverse events. Both groups demonstrated clinically important improvements in lower-extremity functional status. The degree of improvement seemed higher for gait speed, single-leg stance time, and stiffness in the FT+B group compared with the FT group. Limitations Due to the pilot nature of the study, differences between groups did not have adequate power to show statistical significance. Conclusions There is a need for conducting a larger randomized controlled trial to test the effectiveness of an FT+B program after TKA.

Agility and Perturbation Training Techniques in Exercise Therapy for Reducing Pain and Improving Function in People With Knee Osteoarthritis: A Randomized Clinical Trial

Background Impairment-based exercise programs have yielded only small to moderate benefits in reducing pain and improving function in people with knee osteoarthritis (OA). It has previously been proposed that adding agility and perturbation training to exercise programs for people with knee OA may improve treatment effects for pain and function. Objective The purpose of this study was to examine the effectiveness of adding agility and perturbation techniques to standard exercise therapy compared with the standard exercise program alone for people with knee OA. Design This was a single-blinded randomized controlled trial. Setting The study was conducted in the outpatient physical therapy clinic of a large, university-based health center. Participants One hundred eighty-three people with knee OA (122 women, 61 men) participated. Interventions Participants were randomly assigned to either a group that received agility and perturbation training with standard exercise therapy or a group that received only the standard exercise program. Measurements The outcome measures were self-reported knee pain and function, self-reported knee instability, a performance-based measure of function, and global rating of change. Results Although both groups exhibited improvement in self-reported function and in the global rating of change at the 2-, 6-, and 12-month follow-up periods, there were no differences between groups on these outcomes. There was no reduction in knee pain or improvement in performance-based function in either group. Limitations It is possible that more-intense application of the interventions or application of the interventions to participants with knee OA who were at greater risk for falling may have yielded additive effects of the agility and perturbation training approach. Conclusions Both intervention groups exhibited improvement in self-reported function and the global rating of change. Our results, however, did not support an additive effect of agility and perturbation training with standard exercise therapy in our sample of individuals with knee OA. Further study is needed to determine whether there are subgroups of individuals who might achieve an added benefit with this approach.

Instability, Laxity, and Physical Function in Patients With Medial Knee Osteoarthritis

Background and Purpose: Studies have identified factors that contribute to functional limitations in people with knee osteoarthritis (OA), including quadriceps femoris muscle weakness, joint laxity, and reports of knee instability. However, little is known about the relationship among these factors or their relative influence on function. The purpose of this study was to investigate self-reported knee instability and its relationships with knee laxity and function in people with medial knee osteoarthritis (OA). Participants: Fifty-two individuals with medial knee OA participated in the study. Methods: Each participant was classified into 1 of 3 groups based on reports of knee instability. Limb alignment, knee laxity, and quadriceps femoris muscle strength (force-generating capacity) were assessed. Function was measured with the Knee Injury and Osteoarthritis Outcome Score (KOOS) and a stair-climbing test (SCT). Group differences were detected with one-way analyses of variance, and relationships among variables were assessed with the Eta2 statistic and hierarchical regression analysis. Results: There were no differences in alignment, laxity, or strength among the 3 groups. Self-reported knee instability did not correlate with medial laxity, limb alignment, or quadriceps femoris muscle strength. Individuals reporting worse knee instability scored worse on all subsets of the KOOS. Self-reported knee instability scores significantly contributed to the prediction of all measures of function above that explained by quadriceps femoris muscle force, knee laxity, and alignment. Neither laxity nor alignment contributed to any measure of function. Discussion and Conclusion: Self-reported knee instability is a factor that is not directly associated with knee laxity and contributes to worse function. Further research is necessary to delineate the factors that contribute to self-reported knee instability and reduced function in this population.

Interrater Reliability and Validity of the Stair Ascend/Descend Test in Subjects With Total Knee Arthroplasty

OBJECTIVE (1) To determine the interrater reliability and measurement error of an 11-step stair ascend/descend test (STTotal-11) and stair up (ascend) test (STUp-11); (2) to seek evidence for the STTotal-11 and STUp-11 as valid measures of physical function by determining if they relate to measures of physical function and do not relate to measures not of physical function; and (3) to explore if the STTotal-11 and STUp-11 scores relate to lower-extremity muscle weakness and knee range of motion (ROM) in subjects with total knee arthroplasty (TKA). DESIGN Cross-sectional study. SETTING Academic center. PARTICIPANTS Subjects (N=43, 30 women; mean age, 68+/-8y) with unilateral TKA. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES STTotal-11 and STUp-11 were performed twice, and scores were compared with scores on 4 lower extremity performance-based tasks, 2 patient-reported questionnaires of physical function, 3 psychologic factors, knee ROM, and strength of quadriceps, hip extensors, and abductors. RESULTS Intraclass correlation coefficient was .94 for both the STTotal-11 and STUp-11, standard error of measurements were 1.14 seconds and .82 seconds, and minimum detectable change associated with 90% confidence interval was 2.6 seconds and 1.9 seconds, respectively. Correlations between stair tests and performance-based measures and knee and hip muscle strength ranged from Pearson correlation coefficient (r)=.40 to .78. STTotal-11 and STUp-11 had a small correlation with one of the patient-reported measures of physical function. Stair tests were not associated with psychologic factors and knee extension ROM and were associated with knee flexion ROM. CONCLUSIONS STTotal-11 and STUp-11 have good interrater reliability and minimum detectable changes adequate for clinical use. The pattern of associations supports the validity of the stair tests in TKA.

Contribution of Hip Abductor Strength to Physical Function in Patients With Total Knee Arthroplasty

Background Investigating modifiable factors that contribute to functional limitations in patients with total knee arthroplasty (TKA) may guide changes in rehabilitation protocols and improve functional outcomes. Whereas quadriceps muscle weakness has been demonstrated to contribute to functional limitations in TKA, the role of hip abductor weakness has not received attention. Objective The purpose of this study was to determine whether hip abductor strength (force-generating capacity) contributes to physical function beyond what can be explained by quadriceps muscle strength in patients after a TKA. Design A cross-sectional design was used in the study. Setting The study was conducted in a clinical laboratory at an academic center. Patients Thirty-one people with TKA (74% female; mean age=68 years, SD=8; mean body mass index=31 kg/m2, SD=5) participated in the study. Measurements Strength of quadriceps muscles and hip abductors was measured using an isokinetic dynamometer. Performance-based physical function was assessed with 4 measures: self-selected walking speed, the Figure-of-8 Walk Test, the Stair Ascend/Descend Test, and the 5-Chair Rise Test. Self-reported physical function was assessed with the Western Ontario and McMaster Universities Osteoarthritis Index Physical Function Subscale. Results In hierarchical regression models, after accounting for demographic and anthropometric factors, quadriceps muscle strength was associated with performance on the Stair Ascend/Descend Test. After accounting for demographic, anthropometric, and quadriceps strength, hip abductor strength was associated with performance on the Stair Ascend/Descend Test, the Figure-of-8 Walk Test, and the 5-Chair Rise Test. Limitations The study design precluded ascertainment of causal relationships. Conclusions After TKA, hip abductor strength influenced physical function in participants more than did demographic or anthropometric measures or quadriceps strength. Longitudinal studies with larger samples are warranted. If findings are replicated, they will justify targeting the hip abductors during rehabilitation after TKA.

Associates of Physical Function and Pain in Patients with Patellofemoral Pain Syndrome

OBJECTIVES To explore whether impairment of muscle strength, soft tissue length, movement control, postural and biomechanic alterations, and psychologic factors are associated with physical function and pain in patients with patellofemoral pain syndrome (PFPS). DESIGN Cross-sectional study. SETTING Rehabilitation outpatient. PARTICIPANTS Seventy-four patients diagnosed with PFPS. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Measurements were self-reported function and pain; strength of quadriceps, hip abduction, and hip external rotation; length of hamstrings, quadriceps, plantar flexors, iliotibial band/tensor fasciae latae complex, and lateral retinaculum; foot pronation; Q-angle; tibial torsion; visual observation of quality of movement during a lateral step-down task; anxiety; and fear-avoidance beliefs. RESULTS After controlling for age and sex, anxiety and fear-avoidance beliefs about work and physical activity were associated with function, while only fear-avoidance beliefs about work and physical activity were associated with pain. CONCLUSIONS Psychologic factors were the only associates of function and pain in patients with PFPS. Factors related to physical impairments did not associate to function or pain. Our results should be validated in other samples of patients with PFPS. Further studies should determine the role of other psychologic factors, and how they relate to anxiety and fear-avoidance beliefs in these patients.

Responsiveness of the activities of daily living scale of the knee outcome survey and numeric pain rating scale in patients with patellofemoral pain.

OBJECTIVE To assess internal and external responsiveness of the Activity of Daily Living Scale of the Knee Outcome Survey and Numeric Pain Rating Scale on patients with patellofemoral pain. DESIGN One group pre-post design. SUBJECTS A total of 60 individuals with patellofemoral pain (33 women; mean age 29.9 (standard deviation 9.6) years). METHODS The Activity of Daily Living Scale and the Numeric Pain Rating Scale were assessed before and after 8 weeks of physical therapy program. Patients completed a global rating of change scale at the end of therapy. The standardized effect size, Guyatt responsiveness index, and the minimum clinical important difference were calculated. RESULTS Standardized effect size of the Activity of Daily Living Scale was 0.63, Guyatt responsiveness index was 1.4, area under the curve was 0.83 (95% confidence interval: 0.72, 0.94), and the minimum clinical important difference corresponded to an increase of 7.1 percentile points. Standardized effect size of the Numeric Pain Rating Scale was 0.72, Guyatt responsiveness index was 2.2, area under the curve was 0.80 (95% confidence interval: 0.70, 0.92), and the minimum clinical important difference corresponded to a decrease of 1.16 points. CONCLUSION Information from this study may be helpful to therapists when evaluating the effectiveness of rehabilitation intervention on physical function and pain, and to power future clinical trials on patients with patellofemoral pain.