Knee Muscle Weakness Research Articles

COMPARING HEALTH OUTCOMES OVER 12 MONTHS BETWEEN YOUTH WITH A SPORT-RELATED KNEE INJURY AND UNINJURED CONTROLS

Purpose: Knee trauma is associated with a 6-fold increased risk of early-onset post-traumatic osteoarthritis (PTOA). Combined with the rising incidence of youth sport-related knee injuries, this is concerning since early-onset PTOA results in greater years lived with disability and reduced health-related quality of life (QOL) compared to later-onset, non-traumatic forms of OA. Consequences of a knee injury, including knee-related symptoms, knee muscle weakness, physical inactivity, and adiposity, are risk factors for or features of PTOA.

Knee muscle strength in runners who have had knee surgery: differences between limbs and associations with functional performance

Introduction: Knee muscle weakness has been associated with an increased risk of various overuse injuries in runners and incident knee osteoarthritis; however, little is known about knee strength in runners, particularly those who are at high risk of osteoarthritis who have previously had knee surgery. The aim of this study was to explore differences in knee extensor and flexor strength between surgical and non-surgical limbs in runners with a history of knee surgery, and to explore if knee strength is associated with functional performance. Methods: A convenience sample of 38 runners (run ≥10km/week, ≥3 sessions/week) who had unilateral knee surgery (45% anterior cruciate ligament reconstruction) were recruited (33.2±6.8 years, 11 women). Three maximal voluntary isometric contractions of the knee extensors and flexors were performed at 60° knee flexion (Biodex dynamometer). The highest torque value (Nm) for the knee extensors and flexors for each leg was used for analysis. Functional performance was assessed via three trials of the hop for distance test, with the furthest distance hopped for each leg recorded. Paired t-tests were used to explore differences in knee strength between limbs (whole group and stratified by sex) and partial correlations were used to explore associations between knee strength and hop for distance, controlling for mass, age, and sex. Results: There was no significant difference in knee extensor strength between the surgical and non-surgical limbs (surgical=205.9±53.4Nm, non-surgical=215.5±57.9Nm; p=0.087, Cohen’s d=0.285). A significant difference was observed between limbs for knee flexor strength (surgical=103.6±24.1Nm, non-surgical=112.3±28.6Nm; p=0.001, Cohen’s d=0.576). When examining men only, the same results were found, but there were no significant differences between limbs for women. Small to moderate non-significant associations were observed between knee strength and hop for distance on both the surgical (knee extensor r=0.321, p=0.060; knee flexor r=0.333, p=0.051) and non-surgical limbs (knee extensor r=0.286, p=0.095; knee flexor r=0.093, p=0.596). Discussion: Runners who have had unilateral knee surgery demonstrate knee flexor weakness in the surgical limb, but not knee extensors, although differences may be sex specific. Small to moderate non-significant associations between knee strength and hop for distance indicate that factors other than knee strength may influence functional performance in runners who have had knee surgery. Conflict of interest statement: My co-authors and I acknowledge that we have no conflict of interest of relevance to the submission of this abstract.

Individuals with mild-to-moderate hip osteoarthritis have lower limb muscle strength and volume deficits

BackgroundIndividuals with advanced hip osteoarthritis (OA) exhibit generalized muscle weakness of the affected limb and so clinical practice guidelines recommend strength training for the management of hip OA. However, the extent and pattern of muscle weakness, including any between-limb asymmetries, in early stages of the disease are unclear. This study compared hip and knee muscle strength and volumes between individuals with mild-to-moderate symptomatic and radiographic hip OA and a healthy control group.MethodsNineteen individuals with mild-to-moderate symptomatic and radiographic hip OA (n = 12 unilateral; n = 7 bilateral) and 23 age-matched, healthy controls without radiographic hip OA or hip pain participated. Isometric strength of the hip and knee flexors and extensors, and hip abductors and adductors were measured. Hip and thigh muscle volumes were measured from lower limb magnetic resonance images. A full-factorial, two-way General Linear Model was used to assess differences between groups and between limbs.ResultsParticipants in the hip OA group demonstrated significantly lower knee flexor, knee extensor, hip flexor, hip extensor and hip abductor strength compared to controls and had significantly lower volume of the adductor, hamstring and quadriceps groups, and gluteus maximus and gluteus minimus muscles, but not tensor fasciae latae or gluteus medius muscles. There were no between-limb strength differences or volume differences within either group.ConclusionsAtrophic, bilateral hip and knee muscle weakness is a feature of individuals with mild-to-moderate hip OA. Early interventions to target muscle weakness and prevent the development of strength asymmetries that are characteristic of advanced hip OA appear warranted.

Determinants of physical functioning in women with knee osteoarthritis.

Knee osteoarthritis (OA) is an important health problem with its high prevalence and association with pain and functional disability in physical tasks and activities especially in women. To explore the impacts of widely seen demographic, pathological, psychological, and impairment factors on physical functioning in women with knee OA using the performance-based and self-reported measures. One hundred and ten women with knee OA participated in this study. Performance-based measures included the 10-m walk test, timed up and go (TUG) test, and a stair test. Self-reported physical functioning was measured using the Western Ontario and McMasters Universities OA Index. Knee muscle strength, pain intensity, flexion range of motion (ROM), body mass index (BMI), radiographic severity, and anxious and depressive symptoms were measured. Age, disease duration, and comorbidities were recorded. Correlation and linear regression analyses were used to assess the associations. In the linear regression models, knee muscle weakness, limited knee flexion ROM, pain intensity, and older age contributed to 65% of variance in physical performance measures mostly explained by knee muscle weakness. Knee pain intensity, BMI, anxiety, and knee muscle weakness contributed to 60% of variance in WOMAC physical function score mostly explained by pain. Radiologic severity, depression, comorbidities, and disease duration did not have a significant association (P < 0.05). Performance-based measures had significant but moderate correlations with WOMAC physical function score (r range 0.51-0.57, P < 0.05). In women with knee OA, knee muscle strength was the main determinant of performance-based physical functioning together with knee flexion ROM, knee pain, and age. Knee pain was the main determinant of self-reported physical functioning. BMI, anxiety, and knee muscle strength had some contributions as well. Performance-based and self-reported measures had moderate relations and evaluate different aspects of physical functioning. In the management of women with knee OA strengthening of weak knee muscles, improving limited flexion ROM, pain management, weight loss, and improving anxiety should be considered as a priority and performance-based and self-reported measures should be used together for a comprehensive evaluation of physical functioning.

Asymmetries and relationships between dynamic loading, muscle strength, and proprioceptive acuity at the knees in symptomatic unilateral hip osteoarthritis.

IntroductionHigh joint loading, knee muscle weakness, and poor proprioceptive acuity are important factors that have been linked to knee osteoarthritis (OA). We previously reported that those with unilateral hip OA and bilateral asymptomatic knees are more predisposed to develop progressive OA in the contralateral knee relative to the ipsilateral knee. In the present study, we evaluate asymmetries in muscle strength and proprioception between the limbs and also evaluate relationships between these factors and joint loading that may be associated with the asymmetric evolution of OA in this group.MethodsSixty-two participants with symptomatic unilateral hip OA and asymptomatic knees were evaluated for muscle strength, joint position sense and dynamic joint loads at the knees. Muscle strength and proprioception were compared between limbs and correlations between these factors and dynamic joint loading were evaluated. Subgroup analyses were also performed in only those participants that fulfilled criteria for severe hip OA.ResultsQuadriceps muscle strength was 15% greater, and in the severe subgroup, proprioceptive acuity was 25% worse at the contralateral compared to ipsilateral knee of participants with unilateral hip OA (P <0.05). In addition, at the affected limb, there was an association between decreased proprioceptive acuity and higher knee loading (Spearman’s rho = 0.377, P = 0.007) and between decreased proprioceptive acuity and decreased muscle strength (Spearman’s rho = −0.328, P = 0.016).ConclusionsThis study demonstrated asymmetries in muscle strength and proprioception between the limbs in a unilateral hip OA population. Early alterations in these factors suggest their possible role in the future development of OA at the contralateral ‘OA-predisposed knee’ in this group. Furthermore, the significant association observed between proprioception, loading, and muscle strength at the affected hip limb suggests that these factors may be interrelated.

Knee muscle strength after recent partial meniscectomy does not relate to 2-year change in knee adduction moment.

Knee muscle weakness and a greater external knee adduction moment are suggested risk factors for medial tibiofemoral knee osteoarthritis. Knee muscle weakness and a greater knee adduction moment may be related to each other, are potentially modifiable, and have been observed after arthroscopic partial meniscectomy. The aim of this exploratory study was to determine if knee muscle weakness 3 months after arthroscopic partial meniscectomy (baseline) is associated with an increase in external knee adduction parameters during the subsequent 2 years. Eighty-two participants undergoing medial arthroscopic partial meniscectomy were assessed at baseline, and 66 participants who were reassessed 2 years later were included in our study. Isokinetic muscle strength and external adduction moment parameters (peak and impulse) during normal and fast walking were measured at baseline and followup. Multiple linear regression models were used to examine the association between baseline muscle strength and 2-year change in adduction moment parameters. A post hoc power calculation showed we had 80% power to detect a correlation of 0.31 between baseline muscle strength and change in the external knee adduction, with an alpha error of 0.05 and two-sided significance. Maximal isokinetic muscle strength 3 months after arthroscopic partial meniscectomy was not associated with change in adduction moment parameters (p value range from 0.12 to 0.96). No evidence was found to suggest that improving maximal knee muscle strength after a recent arthroscopic partial meniscectomy would reduce change in knee adduction moment observed during the subsequent 2 years. As muscle function is modifiable, future investigation of other aspects of muscle function that may relate to change in knee adduction moment is warranted.

A Longitudinal Study of Strength and Gait after Arthroscopic Partial Meniscectomy

Individuals after arthroscopic partial meniscectomy (APM) are at increased risk of developing knee osteoarthritis (OA). Knee muscle weakness and a higher external knee adduction moment (KAM) are potential risk factors for knee OA. This exploratory longitudinal study assessed these risk factors at baseline in an APM group (3 months after surgery) and control group, and again 2 yrs later (follow-up). Eighty-two participants with medial APM and 38 healthy controls were assessed at baseline, with 66 (79%) and 23 (61%), respectively, retested at follow-up. Outcome measures included isokinetic knee muscle strength and medial knee joint load inferred through indices of the KAM during normal and fast-pace walking. Knee muscle strength was reduced by 14%-16% in the APM leg compared with controls at baseline (P ≤ 0.006). However, strength increased in the APM leg over the 2 yrs such that there were no differences compared with controls at follow-up. KAM impulse was at least 20% higher for the APM group (both legs) when compared with controls at baseline and remained similarly higher 2 yrs later (P ≤ 0.022). At baseline peak, KAM was 18% higher in the APM leg as compared with controls only during fast-pace walking (P = 0.013). The peak KAM increased over the 2 yrs in the APM leg by 8%-9% (P ≤ 0.032), although there were no differences in change in KAM between the APM leg and controls. This study found that although knee muscle strength improved, dynamic medial joint load increased over the 2 yrs after APM surgery. These findings may aid in developing therapeutic interventions aimed to prevent or delay the onset of knee OA after APM.

Knee Muscle Strength and Visual Acuity are the Most Important Modifiable Predictors of Falls in Patients after Hip Fracture Surgery: A Prospective Study

Our purpose was to identify risk factors for falls among older adults who had recently undergone hip fracture surgery. The subjects in this study were 69 older adults (aged 65 years or more) who had sustained a hip fracture and were admitted to an orthopedic rehabilitation ward after surgery. Potential fall risk factors were assessed using the physiological profile assessment, timed-up-and-go test, berg balance test, and activities-specific balance confidence scale at discharge from the hospital. Each individual was followed for a period of 6 months to obtain information on the incidence of falls. Receiver operating characteristic curves were constructed to determine the optimal cutoff score for each potential risk factor identified. Multivariate logistic regression was then used to identify the significant predictors of falls and their odds ratios (ORs). During the 6-month follow-up period, 10 of the 69 patients experienced one or more falls. The results showed that fallers were older than nonfallers (p=0.009). Fallers also had poorer performance in the high-contrast visual acuity test (p=0.015) and lower knee flexor (p=0.021) and knee extensor (p=0.005) muscle strength values. Multivariate logistic regression analysis showed that high-contrast visual acuity (cutoff score Z=-2.280, OR=6.14, 95% CI 1.13-33.29, p=0.035) and knee extensor muscle strength (cutoff score Z=-1.835, OR=4.81, 95% CI 1.04-22.33, p=0.045) were predictors of falls. Poor visual acuity and knee muscle weakness are modifiable predictors of falls and should be the key target areas in fall-prevention programs for older adults with hip fractures.

Low-Intensity Task-Oriented Exercise for Ambulation-Challenged Residents in Long-Term Care Facilities

The aim of this study was to investigate the effects of a task-oriented ambulation training program in regaining walking, balance, and activity of daily living performance for ambulation-challenged residents with walking potential in long-term care facilities. Fifty ambulation-challenged residents with walking potential were randomly assigned to an individualized task-oriented ambulation training group (30-45 mins, three times a week) or a routine nursing care control group for 4 wks. Each subject was evaluated by a blind evaluator before and after training. Walking function was assessed using walking speed, the Timed Up and Go Test, and the 6-Minute Walk Test. Balance and activities of daily living were measured using the Berg Balance Scale and the Barthel Index, respectively. The training group showed significantly more improvement in walking speed, time to complete the Timed Up and Go Test, and the total score of Berg Balance Scale from baseline to posttest than the control group did. No significant difference between groups was observed on the 6-Minute Walk Test or the Barthel Index. Ambulation-challenged residents with walking potential, as defined by slowing of walking speed with concomitant knee muscle weakness and joint range limitation, showed significant improvement in walking function and balance after a 4-wk task-oriented ambulation training in long-term care facilities.

A study of isokinetic trunk and knee muscle strength in patients with chronic sciatica

Objective To evaluate trunk and knee muscle strength in patients with chronic sciatica. Patients and method Twenty-eight patients with right-side chronic sciatica (group 1, G1) and 40 healthy controls (group 2, G2) were evaluated using an isokinetic dynamometer (Cybex Norm II). Quadriceps and hamstring muscle strength were evaluated at concentric velocities of 60 and 120°/s and the trunk muscles were evaluated at concentric velocities of 60 and 90°/s. Results G1 comprised 15 women and 13 men (mean ± SD age: 34.787 ± 6.06; weight: 65.85 ± 5.33 kg; height: 165 ± 6.92 cm). G2 comprised 20 women and 20 men (mean ± SD age: 35.92 ± 6.66; weight: 67.07 ± 6.12 kg; height: 165.82 ± 7.65 cm. There were no significant inter-group differences concerning these parameters. In G1, the peak torque values for the trunk extensors were 123.71 ± 32.45 and 108.85 ± 32.07 Newton metres (Nm) at angular velocities of 60 and 90°/s, respectively. In G2, the values were 192.73 ± 64.24 and 168.65 ± 53.96 Nm, respectively. In G1, the peak torque values for the trunk flexors were 134.32 ± 30.77 and 124.39 ± 32.59 Nm at angular velocities of 60 and 90°/s, respectively. In G2, they were 177.44 ± 44.1 and 157.81 ± 39.01 Nm, respectively. The difference between G1 and G2 was statistically significant. The peak torque for the right quadriceps in G1 was 100.03 ± 24.45 and 78.71 ± 22.92 Nm at angular velocities of 60 and 120°/s, respectively. In G2, these values were 160.5 ± 36.34 and 131.05 ± 33.42 Nm. The peak torque for the hamstrings in G1 was 56.42 ± 13.02 and 50 ± 13.55 Nm at angular velocities of 60 and 120°/s, respectively. In G2, these values were 97.77 ± 33.32 and 84.72 ± 31.41 Nm. Again the difference between G1 and G2 was statistically significant. We also noted a statistically significant difference between G1 and G2 in terms of the peak quadriceps and hamstring torque values on the left side. In G1, the quadriceps and hamstrings were significantly weaker on the sciatica side than on the unaffected side. Conclusion The present study demonstrated trunk and knee muscle weakness in patients with chronic sciatica, when compared with healthy subjects. This weakness was predominant on the sciatica side. Consequently, the management of these patients should include a knee muscle reinforcement programme.

Assessment of Hip and Knee Muscle Function in Orthopaedic Practice and Research

Isometric evaluation of hip and knee muscle strength can be a useful objective assessment tool in the clinic and may be preferred over other forms of dynamic muscle testing, such as isokinetic assessment or variable-resistance weight-lifting. Assessment of isometric strength with use of a handheld dynamometer requires little skill and is easily administered, relatively inexpensive, valid, reliable, and functional; thus, it could be easily integrated into routine clinical examinations. Surface electrical stimulation, electromyography, and ultrasonography can be used in conjunction with isometric muscle testing for the identification of neuromuscular factors influencing muscle force generation. Further research is warranted to investigate the neural and/or muscular impairments associated with hip and knee muscle weakness in orthopaedic populations, with the ultimate goal of improving rehabilitation strategies.

The relationship between previous hamstring injury and the concentric isokinetic knee muscle strength of irish gaelic footballers

BackgroundHamstring injury is one of the most common injuries affecting gaelic footballers, similar to other field sports. Research in other sports on whether residual hamstring weakness is present after hamstring injury is inconsistent, and no study has examined this factor in irish gaelic footballers. The aim of this study was to examine whether significant knee muscle weakness is present in male Irish gaelic footballers who have returned to full activity after hamstring injury.MethodsThe concentric isokinetic knee flexion and extension strength of 44 members of a university gaelic football team was assessed at 60, 180 and 300 degrees per second using a Contrex dynamometer.ResultsFifteen players (34%) reported a history of hamstring strain, with 68% of injuries affecting the dominant (kicking) limb. The hamstrings were significantly stronger (p < 0.05) on the dominant limb in all uninjured subjects. The previously injured limbs had a significantly lower (p < 0.05) hamstrings to quadriceps (HQ) strength ratio than all other non-injured limbs, but neither their hamstrings nor quadriceps were significantly weaker (p > 0.05) using this comparison. The previously unilaterally injured hamstrings were significantly weaker (p < 0.05) than uninjured limbs however, when matched for dominance. The hamstring to opposite hamstring (H:oppH) strength ratio of the previously injured players was also found to be significantly lower (p < 0.05) than that of the uninjured players.ConclusionHamstring muscle weakness was observed in male Irish gaelic footballers with a history of hamstring injury. This weakness is most evident when comparisons are made to multiple control populations, both within and between subjects. The increased strength of the dominant limb should be considered as a potential confounding variable in future trials. The study design does not allow interpretation of whether these changes in strength were present before or after injury.

Test Methods to Detect Hip and Knee Muscle Weakness and Gait Disturbance in Patients With Hip Osteoarthritis

Rasch A, Dalén N, Berg HE. Test methods to detect hip and knee muscle weakness and gait disturbance in patients with hip osteoarthritis. Objective To evaluate test methods for hip and knee muscle weakness and gait disturbance. Design Test-retest. Setting Orthopedic university clinic. Participants Ten young (age, 36±6y) and 13 elderly (age, 69±8y) healthy volunteers and 11 patients (age, 69±8y) with unilateral hip osteoarthritis (OA) were tested for muscular strength. Twenty-five volunteers (age, 42±14y) underwent gait analysis. Interventions A dynamometer assessing maximal voluntary isometric force of hip and knee muscles and an optosensor walkway detecting limp were developed. Tests evaluated reproducibility and tolerance in patients with OA and elderly subjects. Main Outcome Measures Relative coefficient of variation (CV%) and force (in newtons). Results CV% for unilateral strength measurements ranged from 7% to 12% for specific muscle groups. CV% for gait parameters ranged from 4% to 8%, except for the double-support phase. Tests were well tolerated, and no patient had to discontinue because of fatigue. Differences related to sex, age, and disease were detected. Conclusions Our dynamometer system provides reliable measurements of hip and knee muscle strength in young and old people, and variation is comparable to previous data. Our photocell technique for gait analysis is reliable in people with normal gait. Both methods are attractive because they are affordable, nonstationary, and easy to use.

Short-Term Strength and Pain Changes in Total Hip Arthroplasty Patients

The purpose of this study was to report on three case studies of patients that underwent cementless, total hip arthroplasties. The primary emphasis of the study was on short-term changes in pain and strength. The MEED 3000 system was used to obtain bilateral strength measurements for hip abductors (HA), hip flexors (HF), knee extensors (KE), and for straight leg raising (SLR). A 10-point scale was used to assess pain intensity at rest and during each of the muscle strength tests. The postoperative pain was greatest and remained the longest for performing the SLR test. Increases and decreases in the strength of the operative and nonoperative hip tended to parallel one another over time. Throughout the period studied, strength differences between the operative and nonoperative sides for HF, SLR, and HE were large while the differences for HA were relatively small. The significant hip and knee muscle weakness of the total hip patients seems to support the need for a carefully monitored resistive exercise program following discharge from the hospital. J Orthop Sports Phys Ther 1990;12(1):16-23.