Validation of spirometry prediction equations in western Kenya.

SETTING: Community of Eldoret, Kenya. OBJECTIVE: To test the performance of three commonly used spirometry prediction equations in a healthy Kenyan population. DESIGN: Cross-sectional assessment of healthy adults in Eldoret. RESULTS: Of the 331 subjects enrolled in the study, 282 subjects aged 18-85 years (45% males, 55% females) produced high-quality spirograms. Lung function predictions were made using the Global Lung Initiative 2012 (GLI 2012) prediction equations for African Americans, the National Health and Nutrition Examination Survey III (NHANES III) prediction equations for African Americans, and the Crapo prediction equation. Bland-Altman analyses were performed to measure the agreement between observed and predicted spirometry parameters. Overall, the GLI 2012 and NHANES equations for African Americans performed similarly for forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), significantly overestimating FVC while accurately predicting observed FEV1 values. CONCLUSION: The study brings into question the utility of three major spirometry prediction equations in a Kenyan population. The significant overestimation of FVC by the best-performing equations despite accurate prediction of FEV1 suggests poor performance of these equations in our population.

Neuronal chromatolysis in the subgemmal plexus of gustatory papillae in horses with grass sickness.

REASONS FOR PERFORMING STUDY: Diagnosis of equine grass sickness (EGS) can be challenging. We hypothesised that subgemmal plexus neurons are chromatolytic in EGS. If correct, histopathological examination of gustatory papillae biopsies could aid premortem diagnosis of EGS, and EGS could represent a spontaneous model of subgemmal neuronal chromatolysis to facilitate study of the pathology of structures involved in taste. OBJECTIVE: To compare subgemmal plexi and gustatory papillae in EGS and control horses. STUDY DESIGN: Observational study. METHODS: Conventional histology and immunohistochemistry were used to compare subgemmal plexi and gustatory papillae in post mortem samples from 10 EGS and 13 control horses. RESULTS: Chromatolytic neurons were present in all 57 EGS sections which had identifiable neurons, and in only one of 57 control sections. Blinded examination of all haematoxylin-eosin stained sections from each horse for chromatolysis facilitated accurate differentiation of EGS and control horses, with a sensitivity of 100% (95% confidence interval 93.7-100) and specificity of 98.2% (90.6-100) for diagnosing EGS; however, the presence of chromatolytic neurons in one control section indicated that multiple sections per horse must be analysed to achieve diagnostic accuracy. Equine grass sickness was not associated with alterations in taste bud density or morphology, proportion of taste buds with neurofilament immunopositive intragemmal axons or proportion of taste buds containing cells undergoing apoptosis, suggesting taste buds had adequate neurotrophic support at the time of sampling. Horses with EGS had no detectable alteration in lingual gland morphology, but had increased proportions of apoptotic lingual serous gland cells. CONCLUSIONS: While identification of chromatolytic subgemmal neurons in post mortem samples correctly differentiated EGS and control horses, further study is required to evaluate this technique for premortem EGS diagnosis. Equine grass sickness represents a spontaneous model of subgemmal neuronal chromatolysis that facilitates study of the pathology of structures involved in taste.

Too Fit To Fracture: outcomes of a Delphi consensus process on physical activity and exercise recommendations for adults with osteoporosis with or without vertebral fractures.

UNLABELLED: An international consensus process resulted in exercise and physical activity recommendations for individuals with osteoporosis. Emphasis was placed on strength, balance, and postural alignment. Rather than providing generic restrictions, activity should be encouraged while considering impairments, fracture risk, activity history, and preference, and guidance on spine sparing techniques should be provided. INTRODUCTION: The objectives of this study were to establish expert consensus on key questions posed by patients or health care providers regarding recommended assessment domains to inform exercise prescription, therapeutic goals of exercise, and physical activity and exercise recommendations for individuals with osteoporosis or osteoporotic vertebral fracture. METHODS: The Too Fit To Fracture expert panel identified researchers and clinicians with expertise in exercise and osteoporosis and stakeholder groups. We delivered a modified online Delphi survey (two rounds) to establish consensus on assessment, exercise, and physical activities for three cases with varying risk (osteoporosis based on bone mineral density; 1 spine fracture and osteoporosis; multiple spine fractures, osteoporosis, hyperkyphosis, and pain). Duplicate content analyses of free text responses were performed. RESULTS: Response rates were 52% (39/75) and 69% (48/70) for each round. Key consensus points are the following: (a) Current physical activity guidelines are appropriate for individuals with osteoporosis without spine fracture, but not for those with spine fracture; (b) after spine fracture, physical activity of moderate intensity is preferred to vigorous; (c) daily balance training and endurance training for spinal extensor muscles are recommended for all; (d) providing guidance on spine-sparing techniques (e.g., hip hinge) during activities of daily living or leisure, considering impairments, fracture risk, activity history, and preference, is recommended rather than providing generic restrictions (e.g., lifting <10 lbs, no twisting), but for those with vertebral fracture, especially in the presence of pain, multiple fractures, or hyperkyphosis, the risks of many activities may outweigh the benefits-physical therapist consultation is recommended. Examples of spine-sparing techniques and exercise prescription elements are provided. CONCLUSIONS: Our recommendations guide health care providers on assessment, exercise prescription, and safe movement for individuals with osteoporosis.

Too Fit To Fracture: a consensus on future research priorities in osteoporosis and exercise.

UNLABELLED: An international consensus process identified the following research priorities in osteoporosis and exercise: study of exercise in high-risk cohorts, evaluation of multimodal interventions, research examining translation into practice and a goal to examine fracture outcomes. INTRODUCTION: To identify future research priorities related to exercise for people with osteoporosis with and without osteoporotic spine fracture via international consensus. METHODS: An international expert panel and representatives from Osteoporosis Canada led the process and identified opinion leaders or stakeholders to contribute. A focus group of four patient advocates identified quality of life, mobility, activities of daily living, falls, bone mineral density, and harms as outcomes important for decision-making. Seventy-five individuals were invited to participate in an online survey asking respondents to define future research priorities in the area of osteoporosis and exercise; the response rate was 57%. Fifty-five individuals from seven countries were invited to a half-day consensus meeting; 60% of invitees attended. The results of the online survey, knowledge synthesis activities, and results of the focus group were presented. Nominal group technique was used to come to consensus on research priorities. RESULTS: Research priorities included the study of exercise in high-risk cohorts (e.g., ≥ 65 years, low BMD, moderate/high risk of fracture, history of osteoporotic vertebral fractures, hyperkyphotic posture, functional impairments, or sedentary), the evaluation of multimodal interventions, research examining translation into practice, and a goal to examine fracture outcomes. The standardization of outcomes or protocols that could be evolved into large multicentre trials was discussed. CONCLUSIONS: The research priorities identified as part of the Too Fit To Fracture initiative can be used to inform the development of multicentre collaborations to evaluate and implement strategies for engaging individuals with osteoporosis in a safe and effective exercise.

Scores on the Safe Functional Motion test predict incident vertebral compression fracture.

UNLABELLED: The Safe Functional Motion test (SFM) was developed to document movement strategies used to perform everyday activities that may increase the risk for osteoporotic fracture. After adjusting for variables known to predict vertebral compression fracture (VCF), baseline score on the SFM was a significant independent predictor of incident VCF at 1- and 3-year follow-ups. INTRODUCTION: Functional movements may contribute to risk for VCF. We hypothesize that scores on the SFM, a performance-based test of physical function, are associated with incident VCF. METHODS: An osteoporosis clinic database was queried for men and women ≥ 50 years with an initial SFM and corresponding data for prevalent VCF, history of injurious falls, femoral neck bone mineral density (fnBMD), osteoporosis medication use, and incident morphometric VCF at 1-year (n = 878) and 3-year follow-ups (n = 503). Multiple logistic regressions, adjusted for gender, age, injurious fall(s), fnBMD, prevalent VCF at baseline, and osteoporosis medication use, were used to determine whether SFM score was associated with incident VCF at follow-up visits. RESULTS: Baseline SFM score was a significant independent predictor of incident VCF at 1-year follow-up (adjusted odds ratio (95 % confidence intervals (CI)) = 0.818 (0.707, 0.948); p < 0.008) and 3-year follow-up (adjusted odds ratio (95 % CI) = 0.728 (0.628, 0.844); p < 0.0001). Baseline fnBMD and osteoporosis medication use were significant predictors at 1-year (p = 0.05 and < 0.0001, respectively) and 3-year (p < 0.01 and 0.001, respectively) follow-ups. At 3-year follow-up, gender and prevalent VCF were also significant predictors (p = 0.003 and 0.007, respectively). CONCLUSIONS: For every 10-point increase in SFM score, the odds of future VCF decreases by 18 % at 1 year and 27 % at 3 years after adjusting for known covariates. The SFM may aid in the identification of modifiable functional risk factors for VCF.

Too Fit To Fracture: exercise recommendations for individuals with osteoporosis or osteoporotic vertebral fracture.

SUMMARY: A consensus process was conducted to develop exercise recommendations for individuals with osteoporosis or vertebral fractures. A multicomponent exercise program that includes balance and resistance training is recommended. INTRODUCTION: The aim was to develop consensus on exercise recommendations for older adults: (1) with osteoporosis and (2) with osteoporotic vertebral fracture(s). METHODS: The Grading of Recommendations Assessment, Development, and Evaluation method was used to evaluate the quality of evidence and develop recommendations. Outcomes important for decision making were nominated by an expert panel and patient advocates. They included falls, fractures, bone mineral density (BMD), and adverse events for individuals with osteoporosis/vertebral fractures, and pain, quality of life, and function for those with vertebral fracture. Meta-analyses evaluating the effects of exercise on the outcomes were reviewed. Observational studies or clinical trials were reviewed when meta-analyses were not available. Quality ratings were generated, and informed the recommendations. RESULTS: The outcome for which evidence is strongest is falls. Point estimates of the effects of exercise on falls, fractures, and BMD vary according to exercise type. There is not enough evidence to quantify the risks of exercise in those with osteoporosis or vertebral fracture. Few trials of exercise exist in those with vertebral fracture. The exercise recommendations for exercise in individuals with osteoporosis or osteoporotic vertebral fracture are conditional. The panel strongly recommends a multicomponent exercise program including resistance and balance training for individuals with osteoporosis or osteoporotic vertebral fracture. The panel recommends that older adults with osteoporosis or vertebral fracture do not engage in aerobic training to the exclusion of resistance or balance training. CONCLUSIONS: The consensus of our international panel is that exercise is recommended for older adults with osteoporosis or vertebral fracture, but our recommendations are conditional.

Inclinometer-based measures of standing posture in older adults with low bone mass are reliable and associated with self-reported, but not performance-based, physical function.

UNLABELLED: The association between posture and physical function during daily activities in people at risk for osteoporotic fracture is not clear. We report the reliability of measuring posture using the digital inclinometer and how these measures relate to performance-based and self-reported physical function. INTRODUCTION: This study aims to determine the reliability of a simple clinical method for assessing spine curvatures in people with low bone mass and the association between spine curvature measures and pain, physical function (mobility/activities of daily living (ADL)) and quality of life. METHODS: One rater assessed 36 high-functioning adults, aged 52-82 years, attending an outpatient osteoporosis clinic. A digital inclinometer was used to measure lumbosacral angle (S), lumbar standing posture (L), and thoracic standing posture (T) and ADL performance was assessed using the short form of the Safe Functional Motion test (SFM-6), on two occasions approximately 8.7 days apart. Participants reported average pain intensity over the past week and completed the Timed Up and Go test (TUGT) and the mini-Osteoporosis Quality of Life questionnaire (mini-OQLQ). Acceptable reliability was determined using the intraclass correlation coefficient (ICC). Associations were determined using Pearson's correlation coefficients (r) (and Spearman's rho (r s), for non-normal data). RESULTS: ICC (95 % CI) for S, L, and T = 0.91 (0.82, 0.95), 0.90 (0.82, 0.95), and 0.91 (0.84, 0.95), respectively, for test-retest reliability. Thoracic standing posture was associated with the ADL domain of the mini-OQLQ (r s = -0.39) and the TUGT (r = 0.42). Standing posture was not related to pain or total SFM-6 score. CONCLUSIONS: Digital inclinometer measures provide a quick highly reliable, valid, direct assessment of kyphosis. Use of these measures in the clinical setting is expected to facilitate identification and effective management of postural impairments (e.g., trunk extensor muscle weakness, vertebral fracture) associated with osteoporosis.

Efficacy of low frequency pulsed subsensory threshold electrical stimulation vs placebo on pain and physical function in people with knee osteoarthritis: systematic review with meta-analysis.

OBJECTIVE: To determine if low frequency (≤100 Hz) pulsed subsensory threshold electrical stimulation produced either through pulsed electromagnetic field (PEMF) or pulsed electrical stimulation (PES) vs sham PEMF/PES intervention is effective in improving pain and physical function at treatment completion in adults with knee osteoarthritis (OA) blinded to treatment. METHOD: The relevant studies were identified by searching eight electronic databases and hand search of the past systematic reviews on the same topic till April 5, 2012. We included randomized controlled trials (RCTs) of people with knee OA comparing the outcomes of interest for those receiving PEMF/PES with those receiving sham PEMF/PES. Two reviewers independently selected studies, extracted relevant data and assessed quality. Pooled analyses were conducted using inverse-variance random effects models and standardized mean difference (SMD) for the primary outcomes. RESULTS: Seven small trials (459 participants/knees) were included. PEMF/PES improves physical function (SMD = 0.22, 95% confidence interval (CI) = 0.04, 0.41, P = 0.02, I(2) = 0%), and does not reduce pain (SMD = 0.08, 95% CI = -0.17, 0.32, P = 0.55, I(2) = 43%). The strength of the body of evidence was low for physical function and very low for pain. CONCLUSION: Current evidence of low and very low quality suggests that low frequency (≤100 Hz) pulsed subsensory threshold electrical stimulation produced either through PEMF/PES vs sham PEMF/PES is effective in improving physical function but not pain intensity at treatment completion in adults with knee OA blinded to treatment. Methodologically rigorous and adequately powered RCTs are needed to confirm the findings of this review.

Expression of epidermal growth factor receptor (EGFR) and Ki67 in feline oral squamous cell carcinomas (FOSCC).

The aims of this study were to establish expression of epidermal growth factor receptor (EGFR) and Ki67 in 67 archived biopsy samples of feline oral squamous cell carcinomas (FOSCCs) and to establish if the expression of either markers was predictive of survival. Samples were immunohistochemically labelled for the two proteins and scored. Statistical analyses of data, including Kaplan-Meier survival curves, were performed. All samples expressed both markers although levels differed between samples. Median overall survival was 46 days and 1-year survival was 5%. There was no correlation between Ki67 and EGFR scores (Pearson's correlation coefficient, P = 0.861). Low cellular proliferation (low Ki67 score) was positively correlated with an overall longer survival (Log Rank, P = 0.02) and a trend towards better survival for the high EGFR group was observed (Log Rank, P = 0.076). Ki67 and EGFR immunostaining in FOSCC may be of value as biochemical markers for screening of biopsies from cases of FOSCC.

Relationships between calf muscle density and muscle strength, mobility and bone status in the stroke survivors with subacute and chronic lower limb hemiparesis.

OBJECTIVE: To determine the relationship between muscle density and neuromusculoskeletal status in stroke survivors with subacute and chronic hemiparesis. METHODS: Community-dwelling adults were recruited into one of 3 groups (11 per group): subacute stroke group (SSG, <6 months post-stroke), chronic stroke group (CSG, >1 year post-stroke), or age- and gender-matched control group (CG). Muscle density, muscle mass and tibial bone status (cortical density, mass and polar stress-strain index (pSSI)) were measured bilaterally at the tibial 66% site using peripheral quantitative computed tomography. Muscle strength of ankle plantarflexors and knee extensors was assessed using isokinetic dynamometry. Mobility was assessed using the Berg Balance Scale. Univariate regression analyses by group tested whether side-to-side differences in muscle density and measures of neuromusculoskeletal status were related. RESULTS: In the SSG and CG, relationships were observed for muscle density and ankle plantarflexor strength (R²= 0.365 and 0.503). Muscle density related to muscle mass in the CG only (R²= 0.889). Muscle density related to cortical bone density in the SSG (R²= 0.602) and pSSI in the CSG (R²= 0.434). CONCLUSIONS: Muscle density may provide insight into the side-to-side changes in muscle and bone strength following hemiparetic stroke.

Efficacy of ultrasound therapy for the management of knee osteoarthritis: a systematic review with meta-analysis.

OBJECTIVE: To assess the efficacy of ultrasound therapy (US) for decreasing pain and improving physical function, patient-perception of disease severity, and cartilage repair in people with knee osteoarthritis (OA). METHODS: We conducted a systematic review (to February 2009) without language limits in MEDLINE, EMBASE, Cochrane Library, LILACS, MEDCARIB, CINAHL, PEDro, SPORT-discus, REHABDATA, and World Health Organization Clinical Trial Registry. We included randomized controlled trials of people with knee OA comparing the outcomes of interest for those receiving US with those receiving no US. Two reviewers independently selected studies, extracted relevant data and assessed quality. Pooled analyses were conducted using inverse-variance random effects models. MAIN RESULTS: Six small trials (378 patients) were included. US improves pain [Standardized Mean Difference (SMD) (95% confidence interval (CI))=-0.49 (-0.79, -0.18), P=0.002], and tends to improve self-reported physical function [SMD (CI)=-0.54 (-1.19, 0.12), P=0.11] along with walking performance [SMD (CI)=0.81 (-0.09, 1.72), P=0.08]. Results from two trials (128 patients), conducted by the same group, show a positive effect of US on pain [SMD (CI)=-0.77 (-1.15, -0.39), P<0.001], self-reported physical function [SMD (CI)=-1.25 (-1.69, -0.81), P<0.001], and walking performance [SMD (CI)=1.47 (1.06, 1.88), P<0.001] at 10 months after the intervention concluded. Heterogeneity observed between studies regarding the effect of US on pain was explained by US dose, mode and intensity. The quality of evidence supporting these effect estimates was rated as low. CONCLUSIONS: US could be efficacious for decreasing pain and may improve physical function in patients with knee OA. The findings of this review should be confirmed using methodologically rigorous and adequately powered clinical trials.

Evaluation of synaptophysin as an immunohistochemical marker for equine grass sickness.

It has been proposed that synaptophysin, an abundant integral membrane protein of synaptic vesicles, is an immunohistochemical marker for degenerating neurons in equine grass sickness (GS). In the present study, a statistically generated decision tree based on assessment of synaptophysin-immunolabelled ileal sections facilitated correct differentiation of all 20 cases of GS and 24 cases of non-GS disease (comprising eight horses with colic, six with neuroparalytic botulism and 10 controls). This technique also facilitated correct diagnosis of GS in all three cases that had been erroneously classified as having non-GS disease based on conventional interpretation of haematoxylin and eosin-stained cryostat sections of ileal surgical biopsies. Further prospective studies involving larger numbers of horses are required to fully validate this decision tree. In contrast to GS, botulism did not alter ileal neuron density or synaptophysin labelling, indicating that different mechanisms cause neuronal damage and/or dysfunction in GS and botulism.

A single measure of patellar kinematics is an inadequate surrogate marker for patterns of three-dimensional kinematics in healthy knees.

Patellofemoral disorders, such as osteoarthritis and patellofemoral pain, are thought to be associated with abnormal patellar kinematics. However, assessments of three-dimensional patellar kinematics are time consuming and expensive. The aim of this study was to determine whether a single static measure of three-dimensional patellar kinematics provides a surrogate marker for three-dimensional patellar kinematics over a range of flexion angles. We assessed three-dimensional patellar kinematics (flexion, tilt and spin; lateral, anterior and proximal translation) at sequential static angles through approximately 45 degrees of loaded knee flexion in 40 normal subjects using a validated, MRI-based method. The surrogate marker was defined as the static measure at 30 degrees of knee flexion and the pattern of kinematics was defined as the slope of the linear best fit line of each subject's kinematic data. A regression model was used to examine the relationship between the surrogate marker and pattern of kinematics. The surrogate marker predicted 26% of the variance in pattern of patellar flexion (p<0.001), 27% of the variance in pattern of patellar spin (p=0.003), 11% of the variance in pattern of proximal translation (p=0.037) and 39% of the variance in pattern of anterior translation (p<0.001). No relationships were seen between the surrogate marker and tilt or lateral translation. The results suggest that a single measure of patellar parameters at 30 degrees knee flexion is an inadequate surrogate marker of three-dimensional patellar kinematics; therefore, a complete assessment of patellar kinematics, over a range of knee flexion angles, is preferable to adequately assess patterns of patellar kinematics.

Treatment of forearm fractures.

Fractures of the forearm represent common injuries. Understanding the anatomy and function of the radius, ulna, interosseous membrane, proximal and distal radioulnar joints is critical to appropriate management. Diagnosis can readily be made by examination and radiographs. Well established surgical approaches including the anterior Henry, dorsal Thompson, and ulnar approaches provide excellent access to both the radius and ulna. Multiple fracture patterns are recognized including isolated radius and ulna fractures, combined fractures, Galeazzi fractures, and Monteggia fractures. Surgical management regularly requires open reduction internal fixation with plates (DCP) and screws with vigilance being paid to stable reduction of the proximal and distal radioulnar joints. New directions in the management of forearm fractures include the use of intramedullary fixation and locking plate technology.

Consistency of patellar spin, tilt and lateral translation side-to-side and over a 1 year period in healthy young males.

The purpose of this study was to determine the consistency and symmetry of in vivo measures of patellar spin, tilt, and medial/lateral translation in healthy knees. Patellofemoral joint kinematics were measured bilaterally through a range of loaded knee flexion in 10 active males (aged 19.0 (0.57) years) at baseline, 6, and 12 months using a validated magnetic resonance imaging method. Effects due to time and limb were determined using ANOVA. Variation over 12 months and from side-to-side was summarized as the average of the mean absolute deviations of the measures at 1 degrees increments of knee flexion for corresponding loading cycles for each knee. The measures did not differ over time (p>0.52) or side-to-side (p>0.17). The mean intrasubject variability over the three time points was < or = 1.17 (0.3) degrees for spin and tilt and < or = 0.83 (0.61) mm for lateral translation. The mean intrasubject variability between limbs was 2.14 (1.29) degrees for spin, 0.46 (1.96) degrees for tilt and 1.29 (1.28)mm for lateral translation. The consistency of measures of normal patellar motion over a 1 year period supports application of this methodology to evaluate changes in patellar motion in longitudinal studies involving patient populations.

Polyneuropathy of Finnish horses characterised by inflammatory demyelination and intracisternal Schwann cell inclusions.

REASON FOR PERFORMING STUDY: A neurological disorder characterised by pelvic limb metatarsophalangeal joint extensor paresis has been observed in numerous horses in Scandinavia for the last decade. Very little has been formally reported and there have been no detailed assessments of the neurological signs or neuropathological lesions. OBJECTIVES: To describe the epidemiological and pathological features of an outbreak of 'Scandinavian knuckling syndrome' in a riding stable in southern Finland. METHODS: Clinical neurological examination of 4 cases and neuropathological assessment of tissues of one case were performed. RESULTS: Eleven out of 17 horses fed on ryegrass from a common source showed progressive clinical signs of metatarsophalangeal extensor paresis necessitating euthanasia of 7 horses. Nervous system lesions in one horse consisted of a novel demyelinating, mildly inflammatory peripheral neuropathy, with BiP/GRP positive rough endoplasmatic reticulum Schwann cell inclusions. CONCLUSIONS: The clinical signs and lesions documented differ from any previously described equine polyneuropathy and suggest a primary Schwann cell lesion. POTENTIAL RELEVANCE: The classification of this disease as a novel demyelinating polyneuropathy may assist focused epidemiological investigations.

Patellofemoral joint kinematics in individuals with and without patellofemoral pain syndrome.

BACKGROUND: Patellofemoral pain syndrome is a prevalent condition in young people. While it is widely believed that abnormal patellar tracking plays a role in the development of patellofemoral pain syndrome, this link has not been established. The purpose of this cross-sectional case-control study was to test the hypothesis that patterns of patellar spin, tilt, and lateral translation make it possible to distinguish individuals with patellofemoral pain syndrome and clinical evidence of patellar malalignment from those with patellofemoral pain syndrome and no clinical evidence of malalignment and from individuals with no knee problems. METHODS: Three-dimensional patellofemoral joint kinematics in one knee of each of sixty volunteers (twenty in each group described above) were assessed with use of a new, validated magnetic resonance imaging-based method. Static low-resolution scans of the loaded knee were acquired at five different angles of knee flexion (ranging between -4 degrees and 60 degrees). High-resolution geometric models of the patella, femur, and tibia and associated coordinate axes were registered to the bone positions on the low-resolution scans to determine the patellar motion as a function of knee flexion angle. Hierarchical modeling was used to identify group differences in patterns of patellar spin, tilt, and lateral translation. RESULTS: No differences in the overall pattern of patellar motion were observed among groups (p>0.08 for all global maximum likelihood ratio tests). Features of patellar spin and tilt patterns varied greatly between subjects across all three groups, and no significant group differences were detected. At 19 degrees of knee flexion, the patellae in the group with patellofemoral pain and clinical evidence of malalignment were positioned an average of 2.25 mm more laterally than the patellae in the control group, and this difference was marginally significant (p=0.049). Other features of the pattern of lateral translation did not differ, and large overlaps in values were observed across all groups. CONCLUSIONS: It cannot be determined from our cross-sectional study whether the more lateral position of the patella in the group with clinical evidence of malalignment preceded or followed the onset of symptoms. It is clear from the data that an individual with patellofemoral pain syndrome cannot be distinguished from a control subject by examining patterns of spin, tilt, or lateral translation of the patella, even when clinical evidence of mechanical abnormality was observed.