Determinants of hip and knee flexion range: results from the San Antonio Longitudinal Study of Aging

Demographic and radiographic factors for knee symptoms and range of motion in patients with knee osteoarthritis: a cross-sectional study in Beijing, China

BACKGROUND

Knee osteoarthritis (KOA) causes not only pain, stiffness, and dysfunction of the knee, but also the reduction of the joint range of motion (ROM). This study explored the demographic and radiographic factors for knee symptoms and ROM in patients with symptomatic KOA.

METHODS

The demographic variables, Kellgren-Lawrence (KL) grade, and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) of patients with symptomatic KOA recruited in Beijing were collected. The knee ROM of all patients were also measured. We analyzed the influencing factors for WOMAC and ROM using a generalize linear model, respectively.

RESULTS

This study included a total of 2034 patients with symptomatic KOA, including 530 males (26.1%) and 1504 females (73.0%), with a mean age of 59.17 (± 10.22) years. Patients with advanced age, overweight or obesity, a family history of KOA, a moderate-to-heavy manual labor job and use of nonsteroidal anti-inflammatory drugs (NSAIDs) had significantly higher WOMAC and lower ROM (all P < 0.05). The more the comorbidities, the higher the WOMAC (all P < 0.05). Patients with higher education had better ROM than those with only an elementary education(β = 4.905, P < 0.05). Compared with those KL = 0/1, the WOMAC of patients whose KL = 4 were higher (β = 0.069, P < 0.05), but the WOMAC of those KL = 2 were lower (β = -0.068, P < 0.05). ROM decreased with the increase of KL grade (all P < 0.05).

CONCLUSIONS

KOA patients with advanced age, overweight or obesity, a family history of KOA in first-degree relatives, a moderate-to-heavy manual labor job tended to have more severe clinical symptoms and worse ROM. Patients with more severe imaging lesions tend to have poorer ROM. Symptom management measures and regular ROM screening should be taken early to these people.

UC-II Undenatured Type II Collagen for Knee Joint Flexibility: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Clinical Study

Objective:

Joint-related stress models have been used in the past to induce a standardized load on physical structures, allowing researchers to observe changes in perceived stress on joints as accurately as possible in healthy individuals. Previous studies support the efficacy of UC-II^® undenatured type II collagen (“undenatured collagen”) supplementation in maintaining joint health. The purpose of this study was to assess the effect of undenatured collagen on knee flexibility in healthy subjects who experience activity-related joint discomfort (ArJD).

Methods:

This randomized, double-blind, placebo (PLA)-controlled study was conducted in healthy subjects with ArJD who had no history of osteoarthritis, or joint diseases. Ninety-six (n = 96, 20–55 years old) subjects who reported joint discomfort while performing a standardized single-leg-step-down test were randomized to receive either PLA (n = 48) or 40 mg of undenatured collagen (n = 48) supplementation daily for 24 weeks. Range of motion (ROM) flexion and extension were measured using a digital goniometer.

Results:

At the end of the study, a statistically significant increase in knee ROM flexion was observed in the undenatured collagen group versus the PLA group (3.23° vs. 0.21°; p = 0.025). In addition, an increase in knee ROM extension by 2.21° was observed over time in the undenatured collagen group (p = 0.0061), while the PLA group showed a nonsignificant increase by 1.27° (p > 0.05). Subgroup analysis by age showed a significant increase in knee ROM flexion in subjects >35 years old in the undenatured collagen supplemented group compared with PLA (6.79° vs. 0.30°; p = 0.0092).

Conclusion:

Overall, these results suggest that daily supplementation of 40 mg of undenatured collagen improved knee joint ROM flexibility and extensibility in healthy subjects with ArJD.

Association Between the Amount of Limb Lengthening and Hip Range of Motion After Total Hip Arthroplasty

AIMS

The relationship between prosthetic position and range of motion (ROM) after total hip arthroplasty (THA) has been rigorously examined. However, the effects of limb lengthening on postoperative hip ROM remain unclarified. We aimed to examine the effect of limb lengthening on hip ROM after THA.

METHODS

We retrospectively reviewed the data from 120 patients who underwent unilateral THA. Univariate and multivariate regression models were used to evaluate the effects of the following patient- and surgery-related covariates on hip flexion ROM at 3, 6, and 12 months after THA: age, sex, body mass index, diagnosis, preoperative University of California Los Angeles activity score, preoperative Oxford Hip Score, preoperative flexion ROM, amount of leg lengthening, cup inclination, and cup anteversion.

RESULTS

A large preoperative hip flexion ROM was the strongest predictor of a large hip flexion ROM at 12 months after THA (standardized coefficient: 0.519, P < 0.0001). A larger amount of leg lengthening was associated with a smaller postoperative hip flexion ROM (standardized coefficient: -0.159, P = 0.039), and male sex was another predictor of a smaller postoperative hip flexion ROM (standardized coefficient: -0.204, P = 0.014). Cup inclination (P = 0.99) and anteversion (P = 0.18) were not significantly associated with hip flexion ROM at 12 months after THA.

DISCUSSION

A large amount of limb lengthening was associated with decreased hip flexion ROM after THA. In THA, minimizing the leg length discrepancy is important; however, the postoperative improvement in hip flexion ROM may be limited when a large amount of leg lengthening is needed.

Discrepancy in the Responsiveness to Hip Range of Motion Between Harris and Oxford Hip Scores

Background

The primary objectives of total hip arthroplasty (THA) include mobility improvement and pain relief; however, the correlation between hip range of motion (ROM) and function remains unclear. We aimed to explore how ROM affects hip functions after THA and compare the responsiveness of each component of the modified Harris Hip Score (mHHS) and Oxford Hip Score (OHS) to preoperative and postoperative ROM.

Methods

This prospective observational study involved 120 patients who underwent unilateral THA. Univariate regression analyses were performed using the University of California Los Angeles activity score and mHHS and OHS to determine the effects of preoperative and postoperative flex ROM on clinical scores at 12 months. Multivariate regressions were performed to adjust for the confounding effects of patient factors: age, sex, body mass index, and diagnosis.

Results

A larger preoperative flexion ROM was associated with a higher score in the mHHS socks component (standardized coefficient [SC] = 0.26, P = .0041) at 12 months; the effect on the OHS socks component was not significant (P = .34). A larger flexion ROM at 12 months was associated with higher scores in the mHHS support (SC = 0.21, P = .026), stairs (SC = 0.35, P = .0002), and socks (SC = 0.32, P = .0007) components but had no significant effect on any OHS component. The effects of ROM on University of California Los Angeles activity score were limited.

Conclusions

A discrepancy was noted in the responsiveness to ROM between the two major measurement tools; this difference might be because mHHS and OHS are surgeon- and patient-administered questionnaires, respectively. This discrepancy also suggests that the patients have higher satisfaction than that assumed by the surgeons.

High and Varied Anterior Condyle of the Distal Femur Is Associated with Limited Flexion in Varus Knee Osteoarthritis

OBJECTIVE

This study aimed to evaluate variations in anterior condylar height (ACH) of the distal femur in varus knee osteoarthritis and evaluate the association between ACH and knee flexion.

DESIGN

Computed tomography (CT) images of 171 knees (143 patients; age 73.7 ± 8.3 years; 132 females, 39 males) with symptomatic primary knee osteoarthritis and varus alignment undergoing primary total knee arthroplasty, unilateral knee arthroplasty, or high tibial osteotomy were evaluated. Several other anatomic parameters were measured on CT or radiography. The ACH and knee flexion correlation was analyzed, and factors contributing to knee flexion were determined using multivariable regression analysis.

RESULTS

Medial ACH (mean, 8.1 mm; range, -2.8 to 19.9 mm) was smaller (P < 0.001) but more variable (F = 1.8, P < 0.001) than lateral ACH (mean, 10.7 mm; range, 3.6-18.3 mm). Medial ACH was moderately correlated with flexion (r = -0.44, 95% confidence interval [CI], -0.55 to -0.32), whereas lateral ACH was weakly correlated (r = -0.38; 95% CI, -0.50 to -0.25). On multivariable linear regression analysis of knee flexion, body mass index (B [partial regression coefficient] = -1.1), patellofemoral Kellgren-Lawrence grade (B = -4.3), medial ACH (B = -1.2), medial posterior condylar offset (B = 1.2), age (B = -0.4), and varus alignment (B = -0.6) remained significant independent variables (adjusted R² = 0.35).

CONCLUSIONS

Wide variation and anteriorization of the anterior condyle of the distal femur was observed in advanced osteoarthritis, as an independent determinant of limited knee flexion.

The Effect of Body Mass Index on Clinical Outcomes in Patients Without Radiographic Evidence of Degenerative Joint Disease After Arthroscopic Partial Meniscectomy

PURPOSE

To examine the effect of obesity on clinical outcomes at 1 year after arthroscopic partial meniscectomy.

METHODS

We conducted a secondary analysis of the ChAMP (Chondral Lesions and Meniscus Procedures) randomized controlled trial (N = 256). The visual analog scale for pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS), range of motion, and presence of effusion were assessed preoperatively and at 1 year after arthroscopic partial meniscectomy. Body mass index was categorized as normal weight, 24.99 or less; overweight, 25 to 29.99; or obese, 30 or greater. Analysis of variance or the Cochran-Mantel-Haenszel test was used to examine differences in clinical outcomes between body mass index categories, and mean ± standard deviation or number (percentage) is reported.

RESULTS

Preoperatively, obese patients had worse WOMAC pain (56.2 ± 17.2 vs 61.3 ± 17.2, P = .02), WOMAC physical function (55.8 ± 17.1 vs 62.8 ± 17.1, P = .004), pain visual analog scale (4.9 ± 2.1 vs 4.2 ± 1.9, P = .01), KOOS pain (49.5 ± 14.9 vs 54.0 ± 15.1, P = .02), and KOOS quality-of-life (27.9 ± 18.3 vs 36.9 ± 17.0, P = .001) scores, as well as decreased flexion (121.8° ± 22.6° vs 132.3° ± 16.5°, P = .003), compared with normal-weight patients. Overweight patients (n = 51 [51.5%], P = .03) and obese patients (n = 56 [52.8%], P = .002) were more likely to have knee effusion before surgery than normal-weight patients (n = 17 [34%]). At 1 year after surgery, overweight (130.2° ± 7.7°, P = .03) and obese (128.1° ± 7.1°, P = .003) patients had decreased flexion compared with normal-weight patients (134.5° ± 8.3°).

CONCLUSIONS

Obese patients had worse pain, physical functioning, and quality-of-life scores, as well as decreased flexion, compared with normal-weight patients before arthroscopic partial meniscectomy. At 1 year after arthroscopic partial meniscectomy, there were no statistically significant differences in clinical outcomes but obesity was associated with decreased knee flexion.

LEVEL OF EVIDENCE

Level II, prospective comparative trial.

Muscular Power during a Lifting Task Increases after Three Months of Resistance Training in Overweight and Obese Individuals

Background: This study evaluates the effect on power produced during a modified lifting task in the overweight and obese after three months of either resistance or aerobic training. Methods: Seventeen male subjects divided randomly into two groups performed deadlift and deadlift high pull, both with increasing weights up to maximal power, prior to and after the training programs (three sessions per week). Results: Their mean power increased significantly during the deadlift at 20 kg (14.3%, p = 0.026), 30 kg (17.7%, p = 0.008), 40 kg (16.5%, p = 0.011), 50 kg (14.5%, p = 0.020), and 60 kg (14.3%, p = 0.021) and during the deadlift high pull at 30 kg (9.9%, p = 0.037), 40 kg (10.1%, p = 0.035), and 50 kg (8.2%, p = 0.044) after the resistance training. However, the group that participated in the aerobic training failed to show any significant changes in power performance during either the deadlift or deadlift high pull. Conclusion: Three months of resistance training enhances power outputs during a lifting task with weights from 30 to 50 kg (~40–60% of 1-repetition maximum) in the overweight and obese. Because this test was sensitive in revealing pre-post training changes in lifting performance, it should be implemented in the functional diagnostics for overweight and obese individuals and also complement existing testing methods.

Prevalence of Self-Reported Arthritis Among Elders From Latin America and the Caribbean and Among Mexican Americans From the Southwestern United States

This study examines the prevalence of self-reported arthritis and arthritis symptoms and their relationship to functional limitations in elders from Latin America and the Caribbean and in Mexican Americans from the southwestern United States. This study includes 8,122 elderly aged 60 and older from seven Latin America and Caribbean countries and 2,580 noninstitutionalized Mexican Americans aged 65 or older residing in the southwestern United States. The estimated prevalence of self-reported arthritis ranged from 23.8% in Mexico City to 55.6% in Havana. The prevalence of self-reported pain among arthritic subjects across all countries ranged from 30.7% in older Mexican Americans to 83.7% in Santiago. Arthritis was independently associated with any Activities of Daily Living and any Instrumental Activities of Daily Living limitation across the eight countries after controlling for relevant factors. Self-reported arthritis and arthritis symptoms are highly prevalent among elders from Latin America and the Caribbean and older Mexican Americans and is a significant cause of disability in all studied populations.

Age-related differences in movement strategies and postural control during stooping and crouching tasks

While epidemiologic data suggests that one in four older adults have difficulty performing stooping and crouching (SC) tasks, little is known about how aging affects SC performance. This study investigated differences between young and older adults in lower limb kinematics and underfoot center of pressure (COP) measures when performing a series of SC tasks. Twelve healthy younger and twelve healthy older participants performed object-retrieval tasks varying in: (1) initial lift height, (2) precision demand, and (3) duration. Whole-body center of mass (COM), underfoot COP, and hip and knee angular kinematics (maximum angles and velocities) were analyzed. Compared to younger, older participants moved slower when transitioning into and out of pick-up postures that were characterized by less hip and knee flexion. Older participants also showed a diminished ability to adapt to the changing postural demands of each set of tasks. This was especially evident during longer tasks, whereby older individuals avoided high knee flexion crouching postures that were commonly used by younger participants. Older adults also tended to exhibit faster and more frequent COP trajectory adjustments in the anterior-posterior direction. It is likely that limitations in physical characteristics such as lower limb strength and range of motion contributed to these differences.

Radiological Assessment of the Sacrofemoral Angle: A Novel Method to Measure the Range of Hip Joint Flexion

BACKGROUND

A quantitative and accurate measurement of the range of hip joint flexion (RHF) is necessarily required in the evaluation of disordered or artificial hip joint function. This study aimed to assess a novel method to measure RHF more accurately and objectively.

METHODS

Lateral radiographs were taken of 31 supine men with hip joints extended or flexed. Relevant angles were measured directly from the radiographs. The change in the sacrofemoral angle (SFA) (the angle formed between the axis of the femur and the line tangent to the upper endplate of S1) from hip joint extension to hip joint flexion, was proposed as the RHF. The validity of this method was assessed via concomitant measurements of changes in the femur-horizontal angle (between the axis of the femur and the horizontal line) and the sacrum-horizontal angle (SHA) (between the line tangent to the upper endplate of S1 and the horizontal line), the difference of which should equal the change in the SFA.

RESULTS

The mean change in the SFA was 112.5 ± 7.4°, and was independent of participant age, height, weight, or body mass index. The mean changes in the femur-horizontal and SHAs were 123.0 ± 6.4° and 11.4 ± 3.0°, respectively. This confirmed that the change of SFA between hip joint extension and hip joint flexion was equal to the difference between the changes in the femur-horizontal and SHAs.

CONCLUSIONS

Using the SFA, to evaluate RHF could prevent compromised measurements due to the movements of pelvis and lumbar spine during hip flexion, and is, therefore, a more accurate and objective method with reasonable reliability and validity.

Evaluation of preoperative hip range of motion under general anaesthesia

Hip range of motion (ROM) may be an important preoperative variable, however, measurement of hip ROM can be affected by various factors. The purposes of this study were to compare conventional preoperative ROM measurements with those measurements obtained under general anaesthesia, and to better define the associations between preoperative hip ROM, and demographic, functional, and diagnostic variables.
Conventional preoperative hip ROM and ROM under general anaesthesia were prospectively measured in 471 hips. Harris pain score, the Crowe classification, and the diagnosis were also investigated. 
The hip ROM in all directions under general anaesthesia was significantly greater than conventional preoperative hip ROM. There were correlations between conventional preoperative hip ROM and the Harris hip pain score. Hip ROM with Crowe type I deformity under anaesthesia was significantly greater than in hips with type II, III or IV. ROM under anaesthesia of osteonecrosis hips was significantly greater than osteoarthritis and dislocated hips. Conventional preoperative ROM in men was greater in flexion and external rotation compared to women. Internal rotation motion in women in both conventional preoperative ROM and ROM under anaesthesia was greater than in men. 
Hip pain, Crowe classification and diagnosis could influence preoperative hip ROM. Measurement of hip ROM under general anaesthesia could better reflect true ROM compared to measurement without anaesthesia.

Effect of BMI on Knee Joint Torques in Ergometer Rowing

Although an authoritative panel recommended the use of ergometer rowing as a non-weight-bearing form of exercise for obese adults, the biomechanical characterization of ergometer rowing is strikingly absent. We examined the interaction between body mass index (BMI) relative to the lower extremity biomechanics during rowing in 10 normal weight (BMI 18–25), 10 overweight (BMI 25–30 kg·m−2), and 10 obese (BMI > 30 kg·m−2) participants. The results showed that BMI affects joint kinematics and primarily knee joint kinetics. The data revealed that high BMI leads to unfavorable knee joint torques, implying increased loads of the medial compartment in the knee joint that could be avoided by allowing more variable foot positioning on future designs of rowing ergometers.

Abdomen-thigh contact during forward reaching tasks in obese individuals

During seated forward reaching tasks in obese individuals, excessive abdominal tissue can come into contact with the anterior thigh. This soft tissue apposition acts as a mechanical restriction, altering functional biomechanics at the hip, and causing difficulty in certain daily activities such as bending down, or picking up objects from the floor. The purpose of the study was to investigate the contact forces and associated moments exerted by the abdomen on the thigh during seated forward-reaching tasks in adult obese individuals. Ten healthy subjects (age 58.1 ± 4.4) with elevated BMI (39.04 ± 5.02) participated in the study. Contact pressures between the abdomen and thigh were measured using a Tekscan Conformat pressure-mapping sensor during forward-reaching tasks. Kinematic and force plate data were obtained using an infrared motion capture system. The mean abdomen-thigh contact force was 10.17 ± 5.18% of body weight, ranging from 57.8 N to 200 N. Net extensor moment at the hip decreased by mean 16.5 ± 6.44% after accounting for the moment generated by abdomen-thigh tissue contact. In obese individuals, abdomen-thigh contact decreases the net moment at the hip joint during seated forward-reaching activities. This phenomenon should be taken into consideration for accurate biomechanical modeling in these individuals.

Effect of chiropractic treatment on hip extension ability and running velocity among young male running athletes

OBJECTIVE

This study investigates the effect of chiropractic treatment on hip joint extension ability and running velocity.

METHODS

This was a prospective, randomized, controlled experimental pilot study. Seventeen healthy male junior athletes (age, 17-20 years) training in middle distance running were recruited from local Swedish athletic associations. Hip extension ability and running velocity were measured before and after the study period. Chiropractic investigations comprised motion palpation of the sacroiliac and hip joints and modified Thomas test of the ability to extend the leg. In the treatment group, findings of restrictive joint dysfunctions formed the basis for the choice of chiropractic treatment. The interventions were based on a pragmatic approach consisting of high-velocity, low-amplitude manipulations targeted toward, but not exclusively to, the sacroiliac joints.

RESULTS

The treatment group showed significantly greater hip extension ability after chiropractic treatment than did controls (P < .05). Participants in the treatment group did not show a significant decrease in time for running 30 m after treatment (average, -0.065 seconds; P = .0572), whereas the difference was even smaller for the control subjects (average, -0.003; P = .7344).

CONCLUSIONS

The results imply that chiropractic treatment can improve hip extensibility in subjects with restriction as measured by the modified Thomas test. It could be speculated that the running step was amplified by increasing the angle of step through facilitated hip joint extension ability. The possible effect of chiropractic treatment to enhance the running velocity, by increasing the hip joint extension ability and thereby increasing the running step, remains unproven.

Determinants of range of joint motion in patients with early symptomatic osteoarthritis of the hip and/or knee: an exploratory study in the CHECK cohort

OBJECTIVE

Reduced range of motion (ROM) is supposed to be a characteristic feature of osteoarthritis (OA). Because little is known about determinants of ROM, the objective of the present study was to explore the association between demographic, articular, and clinical factors and ROM in patients with early symptomatic knee and/or hip OA.

DESIGN

Baseline data of 598 participants of the Cohort Hip and Cohort Knee (CHECK) study were used in this cross-sectional study.

METHODS

Separate analyses were performed for participants with knee and participants with hip symptoms. Active knee flexion, and hip internal rotation, external rotation, flexion, adduction, and abduction were assessed using a goniometer. Participants underwent a standardised physical and radiographic examination, and completed a questionnaire. Exploratory regression analyses were performed to explore the association between ROM and demographic [i.e., age, gender, body mass index (BMI)], articular [i.e., osteophytosis, joint space narrowing (JSN)], and clinical (i.e., pain, stiffness) factors.

RESULTS

In patients with early symptomatic knee OA, osteophytosis, bony enlargement, crepitus, pain, and higher BMI were associated with lower knee flexion. JSN was associated with lower ROM in all planes of motion. In addition, osteophytosis, flattening of the femoral head, femoral buttressing, pain, morning stiffness, male gender, and higher BMI were found to be associated with lower hip ROM in two planes of motion.

CONCLUSION

Features of articular degeneration are associated with lower knee ROM and lower hip ROM in patients with early OA. Pain, stiffness, higher BMI, and male gender are associated with lower ROM as well.

Range of motion of large head total hip arthroplasty is greater than 28 mm total hip arthroplasty or hip resurfacing

BACKGROUND

Reduced range of motion of the hip has a detrimental influence on lower limb function. Large diameter head total hip arthroplasty may theoretically have a greater potential for restoring normal hip range of motion due to greater head-neck diameter ratio, and hence provide better function compared to conventional or hip resurfacing arthroplasty.

METHOD

At minimum one year follow-up, range of motion of the operated and contra lateral hips was clinically assessed using digital photographs and bony landmarks in a clinical comparative study. We assessed if 1) large diameter head total hip arthroplasty (55 patients) restores better hip range of motion compared to 28 mm total hip arthroplasty (50 patients) or hip resurfacing (60 patients) 2) large diameter head total hip arthroplasty achieves same hip range of motion as contra lateral normal hips and 3) hip range of motion correlates with the WOMAC score.

FINDINGS

The large diameter head total hip arthroplasty group had significantly greater total arcs of motion (approximately 20°), mostly due to an increase of hip flexion and external rotation, but did not reach normal hip motion. The hip range of motion showed significant correlation with the WOMAC score, especially the flexion arc.

INTERPRETATION

The better hip range of motion of large diameter head total hip arthroplasty is likely due to the greater head to neck diameter ratio and hence seems to be the best option to optimize range of hip motion and improve function after hip arthroplasty.

Effect of obesity on posture and hip joint moments during a standing task, and trunk forward flexion motion

OBJECTIVE

Effects of obesity on trunk forward flexion motion in sitting and standing, and postural adaptations and hip joint moment for a standing work task.

DESIGN

Cross-sectional comparison of obese and normal weight groups.

SUBJECTS

Ten obese subjects (waist girth 121.2+/-16.8 cm, body mass index (BMI) 38.9+/-6.6 kg m(-2)) and 10 age- and height-matched normal weight subjects (waist girth 79.6+/-6.4 cm, BMI 21.7+/-1.5 kg m(-2)).

METHODS

Trunk motion during seated and standing forward flexion, and trunk posture, hip joint moment and hip-to-bench distance during a simulated standing work task were recorded.

RESULTS

Forward flexion motion of the thoracic segment and thoracolumbar spine was decreased for the obese group with no change in pelvic segment and hip joint motion. Obese subjects showed a more flexed trunk posture and increased hip joint moment and hip-to-bench distance for a simulated standing work task.

CONCLUSIONS

Decreased range of forward flexion motion, differing effects within the trunk, altered posture during a standing work task and concomitant increases in hip joint moment give insight into the aetiology of functional decrements and musculoskeletal pain seen in obesity.

Effect of passive stretch on reproducibility of hip range of motion measurements

OBJECTIVE

To examine the intra- and intertester and intra- and interday reliability of hip passive range of motion (PROM) measurements and the effect of passive stretch on the reproducibility of PROM measurements.

DESIGN

Reliability study.

SETTING

Rehabilitation clinic at university hospital.

PARTICIPANTS

Twenty volunteers (12 women, 8 men; age range, 18-45 y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Two physical therapists made 2 PROM measurements on the first day and repeated them once after 2 days. The PROM in hip flexion, extension, and inner rotation and knee flexion were determined. The measurements of the hip flexion and inner rotation involved either 1 or 8 short-term passive stretches. The reproducibility was expressed as the intraclass correlation coefficient (ICC) and the coefficient of variation (CV) (in percent).

RESULTS

The passive stretch increased significantly ( P <.05 to P <.001) the PROM of the hip joint. The reproducibility of the PROM measurement did not increase after repetitive passive stretch. The intra- and interday intra- and intertester ICC and CV of the PROM of the hip flexion and hip inner rotation ranged from .655 to .988 and 2.1% to 12.6%, respectively. The intra- and intertester intra- and interday ICC of the PROM of the hip extension ranged from .740 to .961, and the CV ranged from -85.5% to 242.6%. The intra- and intertester intra- and interday ICC of the PROM of the knee flexion ranged from .497 to .913, and the CV ranged from 2.5% to 9.9%.

CONCLUSIONS

Repetitive stretching increased significantly the PROM in hip flexion and inner rotation, but the reproducibility of the PROM measurement did not improve. The hip flexion and the hip inner rotation PROM measurements had moderate to very high intra- and interday intra- and intertester reliabilities. The reliability of the PROM in hip extension and knee flexion was poor.

Physical function in men with and without hip osteoarthritis

OBJECTIVES

To assess the subjective joint pain and function and the objective physical function of lower extremities in men with hip osteoarthritis (OA), to compare the results with those from age- and sex-matched controls, and to evaluate the reproducibility of the functional tests.

DESIGN

A cross-sectional study.

SETTING

Rehabilitation clinic in a university hospital.

PARTICIPANTS

Twenty-seven volunteer men (age range, 47-64 y) with hip OA and 30 randomly selected, healthy age-matched men.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index, passive range of motion (ROM) of the hip joint measured with a standard goniometer, and physical functioning evaluated with a test battery.

RESULTS

The function and the composite scores of the WOMAC correlated (P<.05) with the degree of radiographically estimated severity of OA. The hips of the control subjects were 13% to 52% more flexible (P range, <.0001-.001) than those of the OA patients. The more the hip was deteriorated, the lower the ROM of the hip was in abduction and in both internal and external rotations. The reproducibility of marching on-the-spot and walking up and down stairs was good in both groups, but in other functional tests the reproducibility was poorer. The controls were significantly (P range, <.05-.01) better at marching, ascending and descending stairs, performing a 25-m walk, and in flexion-extension and abduction-adduction movements compared with the hip OA patients. Most of the WOMAC items were significantly (P<.05) related to the performance tests.

CONCLUSIONS

The WOMAC and the ROM can be considered useful hip OA indicators. Marching on-the-spot and walking up and down stairs are the most reproducible physical functioning tests and can thus be recommended for use for patients with hip OA.

Walking velocity in aged persons: its association with lower extremity joint range of motion

OBJECTIVE

To measure the association between walking velocity and hip and knee flexion range, ethnic background, anthropometrics, comorbid pathologies, and coimpairments, in a sample of community-dwelling aged persons.

METHODS

To reach our objective, we used data from the San Antonio Longitudinal Study of Aging (SALSA), a population-based cohort of Mexican American and European American persons aged 64 to 79. By fitting hierarchical regression models, we measured the variance in the walking velocity over 50 feet explained by hip and knee flexion range, adjusting for the combined influence of demographic and anthropometric variables, coexistent pathologic conditions, impairments, and the examiners who conducted the assessments.

RESULTS

The average walking velocity among the 702 subjects for whom data were available was 73.6 meters per minute (range 20 to 121). Bivariate analyses revealed significant associations between walking velocity and age, sex, ethnic background, height, weight, presence of arthritis, diabetes mellitus, stroke, upper leg pain, peripheral vascular disease, left ventricular hypertrophy, and forced expiratory volume at 1 second. The correlation (r) between walking velocity and flexion range of the hip and knee were 0.40 and 0.35, respectively (P < or = 0.001 for each). Multivariate hierarchical models adjusting for demographic and anthropometric characteristics of the subjects, and examiner variation, revealed that hip and knee flexion range explained 6% of the variance in walking velocity. Adjusting for the presence of comorbid conditions and coimpairments reduced the variance attributable to hip and knee flexion range only slightly, to 5%.

CONCLUSION

Hip and knee flexion range contribute significantly to walking velocity in the SALSA cohort of community-dwelling aged persons.

Epidemiology and impact of rheumatic disorders in the United States Hispanic population

The emergence of a sizable Hispanic population in the US is a relatively recent historical phenomenon, and thus much is still unknown about this group of North Americans. Data from national surveys suggest small differences between Hispanic and non-Hispanic white populations in the age-adjusted prevalence of self-reported arthritic conditions. However, the rate of activity-limitation attributable to arthritis is higher among Hispanic patients. This likely reflects the poorer socioeconomic conditions and lack of health insurance that prevail among Hispanic populations, which may limit their access to rheumatologic care. Osteoporotic vertebral and hip fractures are less frequent, and proximal femoral mineral density is higher, in Hispanic individuals than in non-Hispanic white individuals. The mechanisms for these observations are currently under investigation. There have been no studies of the prevalence of osteoarthritis, rheumatoid arthritis, or systemic lupus erythematosus among Hispanic populations. However, important immunogenetic, clinical, and psychosocial differences between Hispanic and non-Hispanic patients in regard to rheumatoid arthritis and systemic lupus erythematosus have been reported. There is no published information on the prevalence or characteristics of other rheumatic diseases in the US Hispanic population. Emerging evidence suggests considerable underuse of certain health services for arthritis among Hispanic patients, likely due in part to socioeconomic factors. Further research is needed to determine whether biologic, cultural or psychosocial factors contribute to underuse as well. There is clearly a need for data on the prevalence and characteristics of arthritis and other rheumatic and musculoskeletal diseases in this emerging US population.

Prevalence of arthritis in older Mexican Americans

OBJECTIVE

This study examines the prevalence of self-reported physician-diagnosed arthritis and arthritis symptoms and their relationship to functional limitations in Mexican American elderly.

METHODS

We conducted a cross-sectional study using a probability sample of 2,873 non-institutionalized Mexican American men and women aged 65 or older, residing in the southwestern United States. Measures included self-reported physician-diagnosed arthritis, morning pain or stiffness, pain when standing, global health rating, activities of daily living (ADL), instrumental activities of daily living (IADL), depressive symptoms, presence of chronic diseases (diabetes mellitus, hypertension, heart attack, stroke), and body mass index. The Mantel-Haenszel chi-square statistic was used to test differences by arthritis status, and a logistic regression model was used to predict the odds of having arthritis.

RESULTS

The overall prevalence of self-reported physician-diagnosed arthritis in the sample was 40.8 percent, 50.0 percent among women and 28.8 percent among men (P < 0.001). Morning pain or stiffness was reported by 37.7 percent of respondents and pain when standing or walking by 31.9 percent. All comorbid conditions, and both IADL and ADL limitations, were more prevalent in those with arthritis than in those without arthritis. Female sex and several medical conditions were independently associated with self-reported arthritis.

CONCLUSIONS

Self-reported physician-diagnosed arthritis is common among older Mexican Americans. Functional limitation and disability are more prevalent among subjects with arthritis than among those without arthritis.

Range of joint motion and disability in patients with osteoarthritis of the knee or hip

OBJECTIVE

To establish the relationships between the range of joint motion (ROM) and disability in patients with osteoarthritis (OA) of the knee or hip. Two related issues were addressed: (1) the inter-relationships between ROMs of joint actions, and (2) the relationship between ROM and disability.

METHODS

Data on 198 patients with OA of the knee or hip were used. The ROM was assessed bilaterally for the hip and knee, using a goniometer. Disability was assessed using a self-reporting method (questionnaire) and an observational method. Correlation and factor analysis were used to establish the inter-relationships between the ROMs of joint actions. Correlation and multiple regression analyses were carried out to establish the relationships between ROM and disability.

RESULTS

Close inter-relationships were found between the ROMs of the same joint action of the lateral and contralateral joints; inter-relationships between ROMs of different joint actions were substantially weaker. Low ROMs were associated with high levels of disability, both self-reported and observed. Some 25% of the variation in disability levels could be accounted for by differences in ROM. In both knee and hip OA patients, flexion of the knee and extension and external rotation of the hip were found to be most closely associated with disability.

CONCLUSION

Restricted joint mobility, especially in flexion of the knee and extension and external rotation of the hip, appears to be an important determinant of disability in patients with OA.

Modeling impairment: using the disablement process as a framework to evaluate determinants of hip and knee flexion

Elders often present to health care providers with multiple inter-related conditions that determine an individual's ability to function. The disablement process provides a generalized sociomedical framework for investigating the complex pathways from chronic disease to disability. At each stage of the main pathway, associations may exist among primary physical factors and modifying variables that ultimately have downstream effects on the progression toward disability. The purpose of the present analysis is to examine the inter-relationships between a cohesive set of variables primarily at the level of impairment that may affect hip and knee flexion range of motion (ROM). The San Antonio Longitudinal Study of Aging enrolled 833 community dwelling Mexican (MA) and European American (EA) elders aged 64-78 years between 1992 and 1996. Of these, 647 had complete data from both a home-based and performance-based battery of assessments for these analyses. Concerning impairments, hip ROM was measured using an inclinometer, and knee ROM using a goniometer. Pain location and intensity were assessed using the McGill Pain Questionnaire. Peripheral vascular disease was assessed using doppler brachial and ankle systolic blood pressures. Ankle and knee reflexes, and vibratory sensation were assessed by a standardized neurological examination. As to diseases, diabetes was assessed using a combination of blood glucose levels and self-report, and arthritis by self-report. Concerning modifying variables, height and weight were directly measured and used to calculate BMI. Activity level was assessed with the Minnesota Leisure Time Questionnaire. Analgesic use was assessed by direct observation of medications taken within the past two weeks. We used structural equation modeling to test associations between the variables that were specified a priori. These analyses demonstrate the central role of BMI as a determinant of hip and knee flexion ROM. For an increase in level of BMI, the coefficients [SEM] for changes in levels of hip and knee ROM were -0.38 [0.05] and -0.26 [0.05], respectively. A higher BMI resulted in lower hip and knee ROM. BMI was also directly associated with prevalent diabetes (0.10 [0.05]) and arthritis (0.17 [0.05]). However, after adjustment for BMI, diabetes and arthritis did not have direct independent associations with either hip or knee ROM. BMI was also indirectly associated with knee, but not hip, ROM through paths including lower-leg pain, pain intensity, and neurosensory impairments. Diabetes had an indirect association with hip, but not knee ROM, through a path including peripheral vascular disease. In conclusion, BMI is a primary direct determinant of hip and knee ROM. The paths by which diabetes and arthritis lead to physical disability may be mediated, in part, at the level of impairment by BMI's association with joint range of motion. Interventions designed to decrease the impact of diabetes and arthritis on disability should track changes in BMI and joint ROM to measure the paths that account for the intervention's success. The observed associations suggest that interventions targeted to decrease BMI itself may lead to improved function in part through improved joint ROM.