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At least 73 records · Page 4Linked to original sources

PubMed2005

Knee stabilization in patients with medial compartment knee osteoarthritis.

OBJECTIVE: Individuals with medial knee osteoarthritis (OA) experience knee laxity and instability. Strategies aimed at muscle stabilization may influence the long-term integrity of the joint. This study sought to determine how individuals with medial knee OA respond to a rapid valgus knee movement, to investigate the relationship between muscle-stabilization strategies and knee instability. METHODS: Twenty-one subjects with medial knee OA and genu varum and 19 control subjects were tested. Subjects stood with the test limb on a movable platform, comprising a plate that translated laterally to rapidly stress the knee's medial periarticular structures and create a potentially destabilizing sensation at the knee joint. Knee motion and muscle responses were recorded. Subjects rated the condition of their knee with a self-report questionnaire about knee instability during daily activities. RESULTS: Prior to plate movement, the OA subjects demonstrated more medial muscle co-contraction than did controls (P = 0.014). Following plate movement, the OA subjects shifted less weight off the test limb (P = 0.013) and had greater medial co-contraction (P = 0.037). OA subjects without knee instability had higher co-contraction of the vastus medialis medial hamstrings than did those who reported having instability that affected their daily activities (P = 0.038). More knee stability correlated positively with higher co-contraction of the vastus medialis medial hamstrings prior to plate movement (r = 0.459, P = 0.042). CONCLUSION: Individuals with medial knee OA attempt to stabilize the knee with greater co-contraction of the medial muscle in response to laxity that appears on the medial side of the joint only. This strategy presumably contributes to higher joint compression and could exacerbate joint destruction, and therefore needs to be altered to slow or stop the progression of the OA disease process.

Compartment Syndromes↗

PubMed1996

Knee recurvatum in gait: a study of associated knee biomechanics.

OBJECTIVES: To quantitatively evaluate peak knee extensor torque values imparted to the posterior knee structures during gait in patients with knee recurvatum compared with torque values observed in control subjects, and to assess the predictive value of the degree of knee hyperextension and other clinical factors in estimating peak knee extensor torque. DESIGN: A retrospective analysis of clinical and quantitative gait data obtained from patients and control subjects. SETTINGS: A gait laboratory. SUBJECTS: Forty-one consecutive patients with neurologically based impairments presenting with knee hyperextension during gait (52 limbs) and 46 able-bodied control subjects. MAIN OUTCOME MEASURE: Peak knee extensor torque during the stance period of the gait cycle. RESULTS: Although overall, the patient average peak extensor torque was significantly greater (p < .001) than the control subjects' average value, knee extensor torques were within or below a +/- 1 standard deviation range for control subjects in 25% (13) of limbs tested. Peak knee hyperextension angle was a poor predictor of peak extensor torque; there was statistical significance (coefficient .061,p < .001) only for hyperextension angles of < or = 4 degrees. Multiple regression incorporating hyperextension angle and other clinical variables to predict peak knee extensor torque resulted in an adjusted r2 of .53. CONCLUSION: Patients with knee recurvatum have variable peak extensor torque values associated with their knee hyperextension. Knowledge of knee hyperextension angle and other clinical factors are only partially useful in predicting a patient's peak knee extensor torque imparted to the posterior knee structures during walking.

Adult↗

PubMed1993

Knee kinematics and kinetics during locomotor activities of daily living in subjects with knee arthroplasty and in healthy control subjects.

BACKGROUND AND PURPOSE: Knee kinematics and kinetics have not been quantitatively studied during gait, stair negotiation, and rising from a chair in the same subjects, either among healthy control subjects or among subjects with knee joint impairments. Despite this paucity of data, rehabilitation goals often include achieving a specific peak knee torque at a specific, fixed angular velocity. SUBJECTS: We compared the kinematic and kinetic performance of the knees in 15 subjects (19 knees) who had undergone knee arthroplasty (KA group) and 11 healthy subjects (22 knees) who served as a control group. The KA group subjects ranged in age from 61 to 78 years, and the control group subjects ranged in age from 26 to 88 years. The KA group subjects had had knee osteoarthritis, were > or = 1 year postsurgery, and were considered fully rehabilitated. METHODS: All subjects were analyzed during barefoot paced walking, stair ascent and descent, and arising from a chair. RESULTS: Compared with the control subjects, the KA group subjects had significantly different knee sagittal range of motion, angular velocities, and maximum knee moments during loaded knee extension. Vertical ground reactions did not differ significantly between groups. Both groups' maximum extension angular velocity exceeded 350 degrees/s during the swing phase of gait, but the maximum loaded extension velocity averaged only 140 degrees/s (during rising from a chair). Maximum knee flexion moments were approximately 10 to 15 N.m/%BW (knee moments normalized to percentage of body weight in newtons). CONCLUSION AND DISCUSSION: We concluded that locomotor ADLs demand relatively slow loaded angular velocities and low knee torques, a factor that should be considered in knee postarthroplasty exercise prescription.

Activities of Daily Living↗

PubMed2006

[Early clinical outcome of total knee arthroplasty for flexion-contracture deformity knees of different degrees].

OBJECTIVE: To make a retrospective analysis on an early clinical outcome of total knee arthroplasty (TKA) for the knees with different degrees of flexion-contracture deformities. METHODS: Ninety-seven knees of 65 patients undergoing total knee arthroplasty with the Scorpion posterior-stabilized knee prosthesis from January 2000 to December 2003 were reviewed, including 51 osteoarthritis patients (74 knees) and 14 rheumatoid arthritis patients (23 knees). Thirty-three patients underwent unilateral TKA, and 32 patients underwent bilateral TKA. The average range of motion (ROM) before operation was 82.8 degrees (range, 5-140 degrees). According to the preoperative flexion-contracture degrees of the knees, these patients were divided into 2 groups, group A and group B. Group A consisted of the patients with flexion-contracture less than 20 degrees (range, 0-15 degrees), and group B consisted of the patients with flexion-contracture not less than 20 degrees (range, 20-60 degrees). In group A, the average flexion-contracture degree, ROM, KSS (knee society score), and function score were 10.7 +/- 8.0 degrees, 104.6 +/- 20.0 degrees, 29.1 +/- 18.0, and 32.6 +/- 20.7, respectively. But the corresponding data were much worse in group B than in group A, which were 28.2 +/- 7.8 degrees, 60.8 +/- 26.6 degrees, 12.1 +/- 13.2, and 26.8 +/- 18.1. All the operations were primary total knee arthroplasty, and they were performed by the same group of surgeons. The time for the prosthesis installed lasted for 25.6 minutes, and the average tourniquet time was 34.7 minutes. Three or four days after operation, the patients began the continuous passive motion (CPM) and active functional exercise of the knee. RESULTS: The patients were followed up for an average of 2 years and 7 months(range, 8 mon-3.5 yr). During the follow-up period, the average flexion-contracture degree, ROM, KSS, and function score in group A were 0.4 +/- 2.1 degrees, 108.6 +/- 19.0 degrees, 82.1 +/- 13.8, and 72.3 +/- 29.1, respectively; and the corresponding data in group B were 1.3 +/- 3.2 degrees, 98.6 +/- 16.40, 75.9 +/- 8.2, and 81.4 +/- 26.9, respectively. There was no significant difference between the 2 groups. No revision or deep infection was found. CONCLUSION: The curative effect is mainly determined by the surgeon's good operational skills, rich clinical experience, and familiarity with the prosthesis, and it is not influenced by severity of the knee flexion-contracture deformity. The knee ROM after TKA, which has a "toward middle ROM" phenomenon, is influenced by many clinical factors. It is very important for the patient to perform a functional exercise of the knee as early as possible after operation.

Adult↗

PubMed2001

The role of knee alignment in disease progression and functional decline in knee osteoarthritis.

CONTEXT: Knee osteoarthritis (OA) is a leading cause of disability in older persons. Few risk factors for disease progression or functional decline have been identified. Hip-knee-ankle alignment influences load distribution at the knee; varus and valgus alignment increase medial and lateral load, respectively. OBJECTIVE: To test the hypotheses that (1) varus alignment increases risk of medial knee OA progression during the subsequent 18 months, (2) valgus alignment increases risk of subsequent lateral knee OA progression, (3) greater severity of malalignment is associated with greater subsequent loss of joint space, and (4) greater burden of malalignment is associated with greater subsequent decline in physical function. DESIGN AND SETTING: Prospective longitudinal cohort study conducted March 1997 to March 2000 at an academic medical center in Chicago, Ill. PARTICIPANTS: A total of 237 persons recruited from the community with primary knee OA, defined by presence of definite tibiofemoral osteophytes and at least some difficulty with knee-requiring activity; 230 (97%) completed the study. MAIN OUTCOME MEASURES: Progression of OA, defined as a 1-grade increase in severity of joint space narrowing on semiflexed, fluoroscopically confirmed knee radiographs; change in narrowest joint space width; and change in physical function between baseline and 18 months, compared by knee alignment at baseline. RESULTS: Varus alignment at baseline was associated with a 4-fold increase in the odds of medial progression, adjusting for age, sex, and body mass index (adjusted odds ratio [OR], 4.09; 95% confidence interval [CI], 2.20-7.62). Valgus alignment at baseline was associated with a nearly 5-fold increase in the odds of lateral progression (adjusted OR, 4.89; 95% CI, 2.13-11.20). Severity of varus correlated with greater medial joint space loss during the subsequent 18 months (R = 0.52; 95% CI, 0.40-0.62 in dominant knees), and severity of valgus correlated with greater subsequent lateral joint space loss (R = 0.35; 95% CI, 0.21-0.47 in dominant knees). Having alignment of more than 5 degrees (in either direction) in both knees at baseline was associated with significantly greater functional deterioration during the 18 months than having alignment of 5 degrees or less in both knees, after adjusting for age, sex, body mass index, and pain. CONCLUSION: This is, to our knowledge, the first demonstration that in primary knee OA varus alignment increases risk of medial OA progression, that valgus alignment increases risk of lateral OA progression, that burden of malalignment predicts decline in physical function, and that these effects can be detected after as little as 18 months of observation.

Aged↗

PubMed2004

Control of frontal plane knee laxity during gait in patients with medial compartment knee osteoarthritis.

OBJECTIVE: Patients with medial compartment knee osteoarthritis (OA) adopt an abnormal gait pattern, and often develop frontal plane laxity at the knee. The purpose of this study was to quantify the extent of frontal plane knee joint laxity in patients with medial knee OA and genu varum and to assess the effect of joint laxity on knee joint kinetics, kinematics and muscle activity during gait. DESIGN: Twelve subjects with genu varum and medial compartment knee osteoarthritis (OA group) and 12 age-matched uninjured subjects underwent stress radiography to determine the presence and magnitude of frontal plane laxity. All subjects also went through gait analysis with surface electromyography of the medial and lateral quadriceps, hamstrings, and gastrocnemius to calculate knee joint kinematics and kinetics and co-contraction levels during gait. RESULTS: The OA group showed significantly greater knee instability (P = 0.002), medial joint laxity (P = 0.001), greater medial quadriceps-medial gastrocnemius (VMMG) co-contraction (P = 0.043), and greater knee adduction moments (P = 0.019) than the control group. Medial joint laxity contributed significantly to the variance in both VMMG and the knee adduction moment during early stance. CONCLUSION: The presence of medial laxity in patients with knee OA is likely contributing to the altered gait patterns observed in those with medial knee OA. Greater medial co-contraction and knee adduction moments bodes poorly for the long-term integrity of the articular cartilage, suggesting that medial joint laxity should be a focus of interventions aimed at slowing the progression of disease in individuals with medial compartment knee OA.

Adult↗

PubMed2003

Provoked anterior knee pain in medial osteoarthritis of the knee.

The incidence and the causes of provoked anterior knee pain in medial osteoarthritis (OA) of the knee were investigated clinically and radiographically. A retrospective study was performed in 179 primary osteoarthritic knees of 129 patients. Provocative tests were conducted on the patellofemoral (PF) joint to induce retropatellar crepitation, grating pain, tenderness around the patella, and pain on deviating the patella. The femorotibial angle (FTA) was measured on standing anteroposterior radiographs as a parameter of limb alignment. The widths of the medial and lateral joint space of the PF joint were measured on skyline views of standing or 30, 60 or 90 degrees knee flexion. The angle of flexion contracture was measured on lateral radiographs of knees with maximum extension. The lateral shift and tilt of the patella were measured on standing skyline views. Retropatellar crepitation was found in 70% of knees, while provoked anterior knee pain was observed in 35-45% of knees with medial OA of the knee. Standing FTA was significantly greater in knees with tenderness around the patella and pain on deviating the patella than in those without these symptoms (P<0.05). The angle of flexion contracture was significantly greater in knees with provoked symptoms in the PF joint than in those without symptoms (P<0.05). The degree of lateral shift was greater in knees with provoked symptoms (P<0.05). Flexion contracture and varus deformity of the knee with lateralization of the patella may be factors aggravating provoked PF symptoms in medial OA of the knee. The radiographic assessment in this series failed to show a significant relationship between the width of the PF joint space and the incidence of provoked PF symptoms.

Aged↗

PubMed2004

A high flexion total knee arthroplasty design replicates healthy knee motion.

Deep flexion affects both femorotibial contact pattern and the patellofemoral articulation. The purpose of this study was to compare the patellofemoral motion of nonimplanted and implanted knees and to analyze femorotibial kinematics after total knee replacement designed for deep flexion. Three-dimensional patellofemoral kinematics were evaluated during a deep knee bend using fluoroscopy for five control patients with a healthy knee, five patients with an anterior-cruciate-ligament-deficient knee, and 20 patients who had a high flexion total knee arthroplasty. Less translation of patellofemoral contact position was seen in patients who had knee replacements than in patients with healthy knees, but the average motion and the patella tilt angles were similar to the healthy knees. On average, patients who had a total knee arthroplasty had 4.9 degrees normal axial rotation, and all patients had at least -4.4 mm of posterior femoral rollback. The average weightbearing range of motion of the patients in the total knee arthroplasty group was 125 degrees . In this study, patients implanted with a high-flexion knee replacement design had kinematic patterns that were similar to the healthy knee. It can be hypothesized that forces acting on the patella were not substantially increased for patients who had a total knee arthroplasty compared with the control patients.

Anterior Cruciate Ligament↗

PubMedDate not supplied

Development and validation of the international knee documentation committee subjective knee form.

A committee of international knee experts created the International Knee Documentation Committee Subjective Knee Form, which is a knee-specific, rather than a disease-specific, measure of symptoms, function, and sports activity. The purpose of this study was to evaluate the reliability and validity of the new International Knee Documentation Committee Subjective Knee Form. To provide evidence for reliability and validity, we administered the final version of the form, along with the Short Form-36, to 533 patients with a variety of knee problems. Analyses were performed to determine reliability, validity, and differential item function related to age, sex, and diagnosis. Factor analysis revealed a single dominant component, making it reasonable to combine all questions into a single score. Internal consistency and test-retest reliability were 0.92 and 0.95, respectively. Based on test-retest reliability, the value for a true change in the score was 9.0 points. The International Knee Documentation Committee Subjective Knee Form score was related to concurrent measures of physical function (r = 0.47 to 0.66) but not to emotional function (r = 0.16 to 0.26). Analysis of differential item function indicated that the questions functioned similarly for men versus women, young versus old, and for those with different diagnoses. In conclusion, the International Knee Documentation Committee Subjective Knee Form is a reliable and valid knee-specific measure of symptoms, function, and sports activity that is appropriate for patients with a wide variety of knee problems. Use of this instrument will permit comparisons of outcome across groups with different knee problems.

Factor Analysis, Statistical↗

PubMed2005

The International Knee Documentation Committee Subjective Knee Evaluation Form: normative data.

BACKGROUND: The International Knee Documentation Committee Subjective Knee Evaluation Form may be used to measure symptoms, function, and sports activity for people with a variety of knee disorders, including ligamentous and meniscal injuries, osteoarthritis, and patellofemoral dysfunction. To date, normative data have not been established for this valid, reliable, and responsive outcomes instrument. PURPOSE: To provide clinicians and researchers with normative data to facilitate the interpretation of results on the International Knee Documentation Committee Subjective Knee Evaluation Form. STUDY DESIGN: Cross-sectional survey. METHODS: The Subjective Knee Evaluation Form was mailed to 600 people in each of 8 age/gender categories (18-24 years, 25-34 years, 35-50 years, and 51-65 years for both male subjects and female subjects). Participants were drawn from a panel of 550 000 households (1 300 000 subjects) representative of noninstitutionalized persons in the United States and were matched to data from the United States Census Bureau on geographical region, market size, income, and household size. RESULTS: Complete data were available for 5246 knees. Twenty-eight percent of respondents reported an injury, weakness, or other problem with one or both knees. Normative data were determined for respondents as a whole and for the subset of respondents with no history of knee problems. Mean scores were determined for men aged 18 to 24 years (89 +/- 18), 25 to 34 years (89 +/- 16), 35 to 50 years (85 +/- 19), and 51 to 55 years (77 +/- 23); mean scores were also determined for women aged 18 to 24 years (86 +/- 19), 25 to 34 years (86 +/- 19), 35 to 50 years (80 +/- 23), and 51 to 65 years (71 +/- 26). Scores were higher for the subset of respondents with no history of current or prior knee problems. CONCLUSION: Scores on the International Knee Documentation Committee Subjective Knee Evaluation Form vary by age, gender, and history of knee problems. The normative data collected in this article will allow clinicians to interpret how patients with knee injuries are functioning relative to their age- and gender-matched peers and will enable researchers to determine the clinical outcomes of treatment.

Adolescent↗

PubMed2006

Responsiveness of the International Knee Documentation Committee Subjective Knee Form.

BACKGROUND AND PURPOSE: The International Knee Documentation Committee Subjective Knee Form was developed to measure change in symptoms, function, and sports activity in patients treated for a variety of knee conditions. Although previous research has demonstrated reliability and validity of the form, its responsiveness has not been evaluated. The purpose of this study was to determine responsiveness of the International Knee Documentation Committee Subjective Knee Form. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 1. METHODS: Patients who participated in the original validation study for the International Knee Documentation Committee Subjective Knee Form completed the form and a 7-level global rating of change scale that ranged from greatly worse to greatly better after a mean of 1.6 years (range, 0.5-2.3 years). Analyses included calculation of the standardized response mean and mean change in International Knee Documentation Committee Subjective Knee Form score compared to the patient's perception of change on the global rating of change scale. In addition, a receiver operating characteristic curve was plotted to determine the change in score that best distinguished patients who improved from those who did not. RESULTS: The overall standardized response mean was 0.94, which is considered large. With the exception of those who were slightly worse or unchanged, the mean change in the International Knee Documentation Committee Subjective Knee Form score compared to the patients' perceived global ratings of change was as expected (greatly worse, -15.1; somewhat worse, -8.4; slightly worse, 20.6; no change, 10.7; slightly better, 5.9; somewhat better, 18.1; greatly better, 38.7). The receiver operating characteristic curve analysis revealed that a change score of 11.5 points had the highest sensitivity, and a change score of 20.5 points had the highest specificity to distinguish between those who were or were not improved. CONCLUSION: The International Knee Documentation Committee Subjective Knee Form is a responsive measure of symptoms, function, and sports activity for patients with a variety of knee conditions.

Adolescent↗

PubMed2004

Reliability, validity, and responsiveness of the Lysholm knee scale for various chondral disorders of the knee.

BACKGROUND: The Lysholm knee scale is a condition-specific outcome measure that was originally designed to assess ligament injuries of the knee. The purpose of this study was to determine the psychometric properties of the Lysholm knee scale for various chondral disorders of the knee. METHODS: Test-retest reliability, internal consistency, content validity, criterion validity, construct validity, and responsiveness to change were determined for the Lysholm knee scale within subsets of an overall study population of 1657 patients with chondral disorders of the knee. The study population was a heterogeneous group of patients with various types of traumatic and degenerative chondral lesions, including isolated lesions and those associated with meniscal and ligament injuries. RESULTS: The overall Lysholm knee scale and six of the eight domains had acceptable test-retest reliability (intraclass correlation coefficient = 0.91) and internal consistency (Cronbach alpha = 0.65). The overall Lysholm knee scale demonstrated acceptable floor (0%) and ceiling (0.7%) effects; however, the floor effects for the domain of squatting and the ceiling effects for the domains of limp, instability, support, and locking were unacceptable (>30%). There was acceptable criterion validity with significant (p < 0.05) correlations between the overall Lysholm knee scale and the physical functioning, role-physical, and bodily pain domains of the Short Form-12 scale; the pain, stiffness, and function domains of the Western Ontario and McMaster Universities Osteoarthritis Index; and the Tegner activity scale. The overall Lysholm knee scale had acceptable construct validity, with all nine hypotheses demonstrating significance (p < 0.05), and it had acceptable responsiveness to change (effect size, 1.16; standardized response mean, 1.10), with large effects (> or = 0.80) for the domains of pain, limping, swelling, and squatting and a small effect (> or = 0.20) for the domain of instability. CONCLUSIONS: The Lysholm knee scale demonstrated overall acceptable psychometric performance for outcomes assessment of various chondral disorders of the knee, although some domains demonstrated suboptimal performance. Psychometric testing of other condition-specific knee instruments in patients with chondral disorders of the knee would be helpful to allow for comparison of psychometric properties.

Adult↗

PubMed1989

Rehabilitation after lower limb amputation: a comparative study of above-knee, through-knee and Gritti-Stokes amputations.

A study of 169 unilateral amputees under three Disablement Services Centres was performed. The study comprised 88 above-knee, 54 through-knee and 27 Gritti-Stokes amputations. Satisfactory rehabilitation occurred in 33 per cent of above-knee, 62 per cent of through-knee and 44 per cent of Gritti-Stokes patients (56 per cent overall). The better rehabilitation of through-knee versus above-knee amputees (P less than 0.02) was also found in a group of patients matched for comparable age and duration of amputation as well as in a group of age-matched vascular amputees. Through-knee amputees relied significantly less on wheelchairs than above-knee (P = 0.016) and Gritti-Stokes (P = 0.05) amputees. The prosthesis used for the through-knee and Gritti-Stokes amputations was considered unsightly in 50 per cent of cases (versus 31 per cent for the above-knee prosthesis). The superior rehabilitation with through-knee amputations should prompt us to improve both our technique for this amputation and the prostheses currently available. A through-knee amputation should be performed in preference to an above-knee amputation in the case where either is surgically possible, and a below-knee amputation not feasible.

Adult↗

PubMed2002

The function of gastrocnemius as a knee flexor at selected knee and ankle angles.

The gastrocnemius has been viewed as an important contributor at the knee joint as a joint flexor and stabilizer across all the knee and ankle joint angles. The purpose of this study was to investigate the influence of knee and ankle joint angles on the knee flexor function of the gastrocnemius. Seventeen participants were tested on a Biodex dynamometer with the gastrocnemius muscle selectively stimulated at a standardized level of electrical current. The results indicated that both ankle and knee joint angle influence the knee joint flexion moment produced by the gastrocnemius. Further analysis revealed that the flexion moment was greatest with the knee joint straight (180 degrees ) across all ankle joint angles. The greatest reduction in knee flexion moment occurred between 180 and 165 degrees of knee angle. No significant difference was observed in the knee flexion moment between 165 degrees and 115 degrees knee flexion, and little knee flexion moment was observed at knee angles of 90 degrees and 75 degrees. The dramatic reduction of moment between 180 degrees and 165 degrees knee angle is possibly due to the change of moment arm while the little moment production during extreme flexion (90 degrees and 75 degrees ) may be due to the reduction of muscle length.

Adult↗

PubMed2006

Comparison of total knee arthroplasty in stiff and ankylosed knees.

We compared the results of total knee arthroplasties in patients with stiff or ankylosed knees. We retrospectively reviewed 90 total knee arthroplasties in 52 patients with minimum 2 years followup who had less than a 50 degrees arc of flexion preoperatively. Preoperative and intraoperative data were retrieved from a computerized database. Patients were followed for an average of 6.5 years at an outpatient department. Knee Society knee scores improved from 34.6 points preoperatively to 89.5 points postoperatively in the stiff knees and from 47 points preoperatively to 75 points postoperatively in the ankylosed knees. The arc of flexion improved from 35 degrees -69 degrees preoperatively to 1 degrees -94 degrees postoperatively in the stiff knees and from 0 degrees to 3 degrees -77 degrees in the ankylosed knees. There were major complications in four of the 26 ankylosed knees and in two of the 64 stiff knees. The data suggest results of total knee arthroplasty are better in patients with stiff knees than in patients with ankylosed knees.

Adult↗

PubMed1994

Knee disorders in carpet and floor layers and painters. Part I. Isometric knee extension and flexion torques.

Knee morbidity, knee extension torque and knee flexion torque were examined among 168 actively working carpet and floor layers and 146 painters. The study included a questionnaire concerning knee disorders and knee symptoms, a clinical examination of the knees and measurement of isometric knee extension and flexion torque. Knee accidents were reported more frequently by carpet and floor layers than by painters. Tenderness of the knees was noted to an equal extent in the two groups. Knee extension torques gradually decreased by increasing age among carpet and floor layers, but not among painters. Body weight and thigh girth were not related to age among carpet and floor layers, but gradually increased with age among painters. Analysis of covariance showed that the torques were most consistently related to thigh girth and age. In addition, the right knee extension torque was related to occupation and tenderness of the patellofemoral joint; the left knee extension torque was related to the knee pain index. These results suggest that occupational kneeling and internal derangement of the knee affect thigh muscles among actively working house builders.

Adult↗

PubMed2005

Estimation of ACL forces by reproducing knee kinematics between sets of knees: A novel non-invasive methodology.

In situ force in the anterior cruciate ligament (ACL) has been quantified both in vitro in response to relatively simple loads by means of robotic technology, as well as in vivo in response to more complex loads by means of force transducers and computational models. However, a methodology has been suggested to indirectly estimate the in situ forces in the ACL in a non-invasive, non-contact manner by reproducing six-degree of freedom (six-DOF) in vivo kinematics on cadaveric knees using a robotic/UFS testing system. Therefore, the objective of this study was to determine the feasibility of this approach. Kinematics from eight porcine knees (source knees) were collected at 30 degrees , 60 degrees , and 90 degrees of flexion in response to: (1) an anterior load of 100 N and (2) a valgus load of 5 N m. The average of each kinematic data set was reproduced on a separate set of eight knees (target knees). The in situ forces in the ACL were determined for both sets of knees and compared. Significant differences (rho<0.05) were found between the source knees and the target knees for all flexion angles in response to an anterior load. However, in response to valgus loads, there was no significant difference between the source knees and the target knees at 30 degrees and 90 degrees of flexion. It was noted that there was a correlation between anterior knee laxity (the distance along the displacement axis from the origin to the beginning of the linear region of the load-displacement curve) and internal-external rotation. These data suggest that in order to obtain reproducible results one needs to first match knees to knees with comparable anterior knee laxity. Thus, an estimate of the in situ forces in the ACL during in vivo activities might be obtainable using this novel methodology.

Animals↗

PubMed2006

Three-dimensional knee motion before and after high tibial osteotomy for medial knee osteoarthritis.

BACKGROUND: High tibial osteotomy (HTO) is an established surgical option for treating medial knee osteoarthritis. HTO moves the mechanical load on the knee joint from the medial compartment to the lateral compartment by changing the leg alignment, but the effects of the operation remain unclear. The purpose of this study was to evaluate the change in three-dimensional knee motion before and after HTO, focusing on lateral thrust and screw home movement, and to investigate the relationship between the change in knee motion and the clinical results. METHODS: A series of 19 patients with medial knee osteoarthritis who had undergone HTO were evaluated. We performed a clinical assessment, radiological evaluation, and motion analysis at 2.4 years postoperatively. The clinical assessment was performed using the Japanese Orthopaedic Association knee score. RESULTS: The score was significantly improved in all patients after operation. Motion analysis revealed that lateral thrust, which was observed in 18 of the 20 knees before operation, was reduced to 7 knees after operation. Regarding active terminal extension of the knee, three patterns of rotational movement were observed before operation: screw home movement (external rotation), reverse screw home movement (internal rotation), and no rotation. By contrast, after operation, only reverse screw home movement and no rotation were observed; the screw home movement disappeared in all patients. In the knees with reverse screw home movement after operation, the preoperative score was significantly lower than those in the knees with no rotation after operation. CONCLUSIONS: Kinetically, HTO was useful for suppressing lateral thrust in medial knee osteoarthritis, although the rotational movement of the knee joint was unchanged.

Adult↗