Thermographic diagnosis in athletes with patellofemoral arthralgia

Using Dual-Orthogonal Fluoroscopy and CT to Assess the Relationship Between Knee Morphology and Patellar Kinematics in Patients With Patellofemoral Pain

INTRODUCTION

Patellofemoral pain (PFP) is one of the most common knee overuse injuries, with studies suggesting PFP as a precursor for early knee osteoarthritis. The etiology of PFP is multi-factorial; however, patellar mal-tracking has been regarded as a primary mechanism. Details of this multi-factorial mechanism have been unclear because of the limitations in evaluating in-vivo, three-dimensional (3D) patellofemoral joint movement during dynamic activities accurately. Alternatively, studies have demonstrated the high accuracy and repeatability of dual fluoroscopy and CT/MRI for measuring knee joint motion.

OBJECTIVE

This study uses dual fluoroscopy and CT to investigate the associations between joint morphology and patellar kinematics in healthy controls and subjects with PFP.

METHODS

Eight PFP females (29.7±10.6 years) and 10 healthy females (25.0±7.7 years) were recruited and screened by a sports medicine physician. CT imaging was performed on participants in a supine with the knee extended, and ankle and hip in neutral alignment. Dual-orthogonal fluoroscopy measured patellar movement while participants performed a lunge task. A calibration algorithm was used to register the 3D CT model to 2D fluoroscopy image to calculate the relative position and angles of the patella based on the clinical definition of patellar motion. Measures of patellar and trochlear morphology were generated and correlated to kinematic data.

RESULTS AND CONCLUSION

There was a significant difference in the patellar-to-trochlear width ratio; however, no other significant differences in CT morphology measurements were present between groups. For PFP patients in the weight-bearing extended position, there was a moderate positive correlation between the patellar-to-trochlear width ratio and medial-lateral patellar shift (τ = 0.643, p = 0.026). Healthy controls in this position demonstrated a moderate positive correlation between the lateral-trochlear inclination angle and medial-lateral patellar shift (τ = 0.600, p = 0.016) and moderate negative correlation between medial trochlear inclination angle and medial-lateral patellar shift (τ = -0.511, p = 0.040). The findings suggest that, for this cohort, there is correlation between morphology and patellar kinematics. Passive and active stabilizers likely have a role in mal-tracking.

Computer-based automated analysis of X-ray and thermal imaging of knee region in evaluation of rheumatoid arthritis

The aim and objectives of the study are as follows: (1) to perform automated segmentation of knee X-ray images using fast greedy snake algorithm and feature extraction using gray level co-occurrence matrix method, (2) to implement automated segmentation of knee thermal image using RGB segmentation method and (3) to compare the features extracted from the segmented knee region of X-ray and thermal images in rheumatoid arthritis patients using a biochemical method as standard. In all, 30 rheumatoid arthritis patients and 30 age- and sex-matched healthy volunteers were included in the study. X-ray and thermography images of knee regions were acquired, and biochemical tests were carried out subsequently. The X-ray images were segmented using fast greedy snake algorithm, and feature extractions were performed using gray level co-occurrence matrix method. The thermal image was segmented using RGB-based segmentation method and statistical features were extracted. Statistical features extracted after segmentation from X-ray and thermal imaging of knee region were correlated with the standard biochemical parameters. The erythrocyte sedimentation rate shows statistically significant correlations (p < 0.01) with the X-ray parameters such as joint space width and % combined cortical thickness. The skin surface temperature measured from knee region of thermal imaging was highly correlated with erythrocyte sedimentation rate. Among all the extracted features namely mean, variance, energy, homogeneity and difference entropy depict statistically significant percentage differences between the rheumatoid arthritis and healthy subjects. From this study, it was observed that thermal infrared imaging technique serves as a potential tool in the evaluation of rheumatoid arthritis at an earlier stage compared to radiography. Hence, it was predicted that thermal imaging method has a competency in the diagnosis of rheumatoid arthritis by automated segmentation methods.

Acute Responses of Strength and Running Mechanics to Increasing and Decreasing Pain in Patients With Patellofemoral Pain

CONTEXT

  Patellofemoral pain (PFP) is typically exacerbated by repetitive activities that load the patellofemoral joint, such as running. Understanding the mediating effects of changes in pain in individuals with PFP might inform injury progression, rehabilitation, or both.

OBJECTIVE

  To investigate the effects of changing pain on muscular strength and running biomechanics in those with PFP.

DESIGN

  Crossover study.

SETTING

  University research laboratory.

PATIENTS OR OTHER PARTICIPANTS

  Seventeen participants (10 men, 7 women) with PFP.

INTERVENTION(S)

  Each participant completed knee pain-reducing and pain-inducing protocols in random order. The pain-reducing protocol consisted of 15 minutes of transcutaneous electric nerve stimulation (TENS) around the patella. The pain-inducing protocol was sets of 20 repeated single-legged squats (RSLS). Participants completed RSLS sets until either their pain was within at least 1 cm of their pain during an exhaustive run or they reached 10 sets.

MAIN OUTCOME MEASURE(S)

  Pain, isometric hip and trunk strength, and running mechanics were assessed before and after the protocols. Dependent variables were pain, normalized strength (abduction, extension, external rotation, lateral trunk flexion), and peak lower extremity kinematics and kinetics in all planes. Pain scores were analyzed using a Friedman test. Strength and mechanical variables were analyzed using repeated-measures analyses of variance. The α level was set at P < .05.

RESULTS

  Pain was decreased after the TENS (pretest: 3.10 ± 1.95, posttest: 1.89 ± 2.33) and increased after the RSLS (baseline: 3.10 ± 1.95, posttest: 4.38 ± 2.40) protocols (each P < .05). The RSLS protocol resulted in a decrease in hip-extension strength (baseline: 0.355 ± 0.08 kg/kg, posttest: 0.309 ± 0.09 kg/kg; P < .001). Peak plantar-flexion angle was decreased after RSLS (baseline: -13.97° ± 6.41°, posttest: -12.84° ± 6.45°; P = .003). Peak hip-extension (pretest: -2.31 ± 0.46) and hip-abduction (pretest: -2.02 ± 0.35) moments decreased after both the TENS (extension: -2.15 ± 0.48 Nm/kg, P = .015; abduction: -1.91 ± 0.33 Nm/kg, P = .015) and RSLS (extension: -2.18 ± 0.52 Nm/kg, P = .003; abduction: -1.87 ± 0.36 Nm/kg, P = .039) protocols.

CONCLUSIONS

  This study presents a novel and effective method of increasing pain in persons with PFP. Functionally increased pain after RSLS coincides with reduced hip-extensor muscle strength and decreased plantar-flexion angle during running. The TENS treatment decreased pain during running in those with PFP but failed to influence strength. Hip moments were reduced by both protocols, which may demonstrate that acute increases or decreases in pain cause runners to change their mechanics.

Automated hand thermal image segmentation and feature extraction in the evaluation of rheumatoid arthritis

The aim of the study was (1) to perform an automated segmentation of hot spot regions of the hand from thermograph using the k-means algorithm and (2) to test the potential of features extracted from the hand thermograph and its measured skin temperature indices in the evaluation of rheumatoid arthritis. Thermal image analysis based on skin temperature measurement, heat distribution index and thermographic index was analyzed in rheumatoid arthritis patients and controls. The k-means algorithm was used for image segmentation, and features were extracted from the segmented output image using the gray-level co-occurrence matrix method. In metacarpo-phalangeal, proximal inter-phalangeal and distal inter-phalangeal regions, the calculated percentage difference in the mean values of skin temperatures was found to be higher in rheumatoid arthritis patients (5.3%, 4.9% and 4.8% in MCP3, PIP3 and DIP3 joints, respectively) as compared to the normal group. k-Means algorithm applied in the thermal imaging provided better segmentation results in evaluating the disease. In the total population studied, the measured mean average skin temperature of the MCP3 joint was highly correlated with most of the extracted features of the hand. In the total population studied, the statistical feature extracted parameters correlated significantly with skin surface temperature measurements and measured temperature indices. Hence, the developed computer-aided diagnostic tool using MATLAB could be used as a reliable method in diagnosing and analyzing the arthritis in hand thermal images.

Medical Infrared Imaging of Normal and Dysplastic Elbows in Dogs

OBJECTIVE

To investigate the ability of medical infrared imaging to differentiate between normal canine elbows and those with abnormal elbows (elbow dysplasia).

STUDY DESIGN

Prospective cohort study.

ANIMALS

Dogs with normal (n = 15) and abnormal (n = 14) elbows.

METHODS

Infrared imaging was performed on all dogs and data analyzed via descriptive statistics and image pattern analysis software. Animals with elbow dysplasia had arthroscopic procedures to confirm the presence of elbow disease.

RESULTS

Computer recognition pattern analysis was up to 100% correct in identifying abnormal elbows and normal elbows, with the medial images most consistent. The caudal, lateral, and cranial images correctly identified 83-100% abnormal elbows. The caudal and lateral images correctly identified 83% normal elbows. A significant difference in temperature was found between normal and abnormal elbows for the cranial full region of interest, lateral images, and each quadrant.

CONCLUSION

Medical infrared imaging was able to correctly identify known abnormal and known normal elbows in dogs.

Anterior knee pain and cold knees: a possible association in women

Abnormal reactions to environmental cold have been observed in some patients with Anterior Knee Pain (AKP). The aims of this study were to investigate whether palpation of the knee could classify patients into those with and those without cold knees; whether this classification could be objectively validated using thermal imaging; whether the cold and not cold knee groups varied in response to a cold stress test and in patient-reported measures. Fifty eight patients were recruited; palpation classified them into cold and not cold groups. Twenty-one (36%) patients were classified as having a cold knee by palpation: fourteen (36%) females and seven males (37%). Preliminary analysis suggested gender might be an effect modifier and the number of men was small, therefore the analysis focussed on females. Women with cold knees had a significantly smaller patellar skin fold, lower levels of activity and worse scores on the MFIQ, there also appeared to be an association with a traumatic onset. Women with cold knees were more likely to report cold weather affected their knees and they preferred a hot water bottle compared to an ice-pack on their knee; there was also a trend towards having to wear extra tights/long johns in the winter. This study has helped to define a clinical profile for a group of females with AKP and cold knees. This group appears to demonstrate a mild form of Reflex Sympathetic Dystrophy.

Diagnostic imaging of the canine stifle: a review

The stifle joint, a common location for lameness in dogs, is a complex arrangement of osseous, articular, fibrocartilaginous, and ligamentous structures. The small size of its component structures, restricted joint space, and its intricate composition make successful diagnostic imaging a challenge. Different tissue types and their superimposition limit successful diagnostic imaging with a single modality. Most modalities exploit the complexity of tissue types found in the canine stifle joint. Improved understanding of the principles of each imaging modality and the properties of the tissues being examined will enhance successful diagnostic imaging.

Correlating femoral shape with patellar kinematics in patients with patellofemoral pain

The etiology of patellofemoral pain is likely related to pathological femoral shape and soft-tissue restraints imbalance. These factors may result in various maltracking patterns in patients with patellofemoral pain. Thus, we hypothesized that femoral shape influences patellofemoral kinematics, but that this influence differs between kinematically unique subgroups of patients with patellofemoral pain. 3D MRIs of 30 knees with patellofemoral pain and maltracking ("maltrackers") and 33 knees of asymptomatic subjects were evaluated, retrospectively. Dynamic MRI was acquired during a flexion-extension task. Maltrackers were divided into two subgroups (nonlateral and lateral maltrackers) based on previously defined kinematic criteria. Nine measures of femoral trochlear shape and two measures of patellar shape were quantified. These measures were correlated with patellofemoral kinematics. Differences were found in femoral shape between the maltracking and asymptomatic cohorts. Femoral shape parameters were associated with patellar kinematics in patients with patellofemoral pain and maltracking, but the correlations were unique across subgroups within this population. The ability to better categorize patients with patellofemoral pain will likely improve treatment by providing a more specific etiology of maltracking in individual patients.

Thermal imaging of normal and cranial cruciate ligament-deficient stifles in dogs

OBJECTIVE

To investigate the capability of thermography for differentiation between normal stifles and those with cranial cruciate ligament (CCL) rupture in dogs, initially with a full hair coat and 1 hour after clipping the hair coat.

STUDY DESIGN

Prospective study.

ANIMALS

Labrador Retrievers (n=6) with normal stifle joints (controls) and adult dogs (n=10) with CCL rupture.

METHODS

Thermography was performed before, and 60 minutes after, clipping the hair coat from the pelvic limb. Stifle images were classified as normal or abnormal, then subclassified as clipped and unclipped hair coat. CCL deficiency was confirmed at surgery and thermographic images subsequently classified as abnormal before analysis with image processing software.

RESULTS

Using image recognition analysis, differentiation between normal and CCL-deficient stifles in both clipped and unclipped dogs was 85% successful on cranial images, medial, caudal, and lateral images were between 75% and 85% successful. Although there were significant increases in skin temperature after clipping in both groups (P<.0002-.0001), there were no significant temperature differences between normal and CCL-deficient stifles when the entire stifle was examined.

CONCLUSION

Thermography was successful in differentiating naturally occurring CCL-deficient stifles in dogs, with a success rate of 75-85%. Clipping is not necessary for successful thermographic evaluation of the canine stifle.

CLINICAL RELEVANCE

Thermography may be a useful imaging modality for diagnosis of CCL deficiency in dogs when CCL rupture is suspected but stifle laxity is not evident.

Adolescent patellofemoral pain: implicating the medial patellofemoral ligament as the main pain generator

PURPOSE

The purpose of this study is to define the clinical presentation of adolescent patellofemoral pain.

METHODS

A review was completed of all patients with patellofemoral pain at a children's hospital sports clinic over a 3-year period.

RESULTS

One hundred and one patients (91 female) with 136 symptomatic knees were identified. Mean age was 14.4 years. Knee pain was localized to the anteromedial or anterior region of the knee in 96% of patients and was typically produced with running (94%), jumping (92%) and stair use (69%). On physical examination there was usually a non antalgic gait (99%), no patellofemoral crepitation (98%), normal lower extremity angular (84%) and rotational alignment (94%), with no foot malalignment (>97%). The medial patellofemoral ligament (MPFL) was the most palpably tender area of the knee in 98% of patients. During "lateral apprehension" testing, 89% had pain at the MPFL, but not true apprehension. A "J-sign" was present at terminal knee extension in 65%. Mean Q-angle was 18.7 degrees . Means of all radiographic measures were within normal ranges.

CONCLUSION

The prototypical patient had anterior/anteromedial knee pain of insidious onset during running and jumping. The most consistent physical findings were focal tenderness at the MPFL, positive terminal J-sign, and an elevated Q-angle. Most patients required only nonsurgical treatments, but 18% underwent surgical interventions for persistent pain.

Quantitative sensory testing of patients with long lasting Patellofemoral pain syndrome

BACKGROUND

Anterior knee pain, diagnosed as Patellofemoral Pain Syndrome (PFPS), is one of the most common musculoskeletal problems found in adolescents and young adults. There is no consensus in medical literature concerning the aetiology of the PFPS.

AIMS

To assess by means of Quantitative Sensory Testing (QST) whether patients suffering from long-lasting unilateral PFPS demonstrate somatosensory dysfunction related to afferent fibres from the local pain area.

METHODS

A descriptive non-experimental study with two independent samples, consisting of 25 men and women between 18 and 44 years of age with unilateral PFPS, and a comparable group of 23 healthy subjects. Somedic Thermotest apparatus was used to assess thresholds of thermal perception, and of heat and cold pain thresholds. Von Frey filaments were used to detect tactile sensitivity. Furthermore, quality and intensity of knee pain, symptoms and signs from a clinical neurological examination were recorded.

RESULTS

Decreased sensitivity to tactile stimulation, when tested with von Frey filaments, was demonstrated on both the painful and pain-free knee in subjects with PFPS, compared to the mean between the knees of the control group (p< or =0.001). The mean detection threshold for warmth was increased by 1.9 degrees C (p< or =0.01) in the painful knee, and 1.4 degrees C (p< or =0.01) in the non-painful knee in the PFPS group, compared to the mean of the healthy control group. The mean detection threshold for cold was increased by 1.6 degrees C (p< or =0.01) in the painful knee of the PFPS group, compared to the control group. These findings were supported by clinical sensory tests. No significant differences of mean thermal pain thresholds between the PFPS group and controls were found, and there were no significant differences in mean detection thresholds for warmth, cold or thermal pain thresholds between the painful and the non-painful knees in the PFPS group.

CONCLUSION

This study demonstrated an abnormal sensory function in the painful and non-painful knee in some individuals with long lasting unilateral Patellofemoral Pain Syndrome using Quantitative Sensory Testing supported by clinical neurological examinations. A dysfunction of the peripheral and/or the central nervous system may cause neuropathic pain in some subjects with PFPS.

An Accurate and Reliable Method of Thermal Data Analysis in Thermal Imaging of the Anterior Knee for Use in Cryotherapy Research

OBJECTIVE

To develop an anatomic marker system (AMS) as an accurate, reliable method of thermal imaging data analysis, for use in cryotherapy research.

DESIGN

Investigation of the accuracy of new thermal imaging technique.

SETTING

Hospital orthopedic outpatient department in England.

PARTICIPANTS

Consecutive sample of 9 patients referred to anterior knee pain clinic.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Thermally inert markers were placed at specific anatomic locations, defining an area over the anterior knee of patients with anterior knee pain. A baseline thermal image was taken. Patients underwent a 3-minute thermal washout of the affected knee. Thermal images were collected at a rate of 1 image per minute for a 20-minute re-warming period. A Matlab (version 7.0) program was written to digitize the marker positions and subsequently calculate the mean of the area over the anterior knee. Virtual markers were then defined as 15% distal from the proximal marker, 30% proximal from the distal markers, 15% lateral from the medial marker, and 15% medial from the lateral marker. The virtual markers formed an ellipse, which defined an area representative of the patella shape. Within the ellipse, the mean value of the full pixels determined the mean temperature of this region. Ten raters were recruited to use the program and interrater reliability was investigated.

RESULTS

The intraclass correlation coefficient produced coefficients within acceptable bounds, ranging from .82 to .97, indicating adequate interrater reliability.

CONCLUSIONS

The AMS provides an accurate, reliable method for thermal imaging data analysis and is a reliable tool with which to advance cryotherapy research.

Role of nitric oxide in the physiopathology of pain

Many painful disorders, including joint dysfunctions such as rheumatoid arthritis (RA) or temporomandibular joint disorders (TMD), are associated with hyperthermia of the overlying skin. The same is true of certain intractable chronic pain conditions, such as chronic orofacial pain, which may be associated with TMD. We suggest that this skin hyperthermia, caused by regional vasodilation, is induced by extravascular nitric oxide (NO). Extravascular NO can be produced in the affected joint by osteoblasts, chondrocytes, and macrophages, by mechanical stimulation of endothelial cells, or by stimulated neurons. In view of a strong correlation between pain and skin hyperthermia in these disorders, and the evidence that NO enhances the sensitivity of peripheral nociceptors, we also suggest that at least this kind of pain is associated with excessive local level of NO. This hypothesis can be verified by dynamic area telethermometry, assessing the effect of NO on the sympathetic nervous function. This mechanism, which is in line with the general role of NO as a mediator between different organ systems, also may be relevant to any pain associated with enhanced immune response. Clinical implications of the proposed mechanism are discussed.

Electrical stimulation of vastus medialis and stretching of lateral thigh muscles in patients with patello-femoral symptoms

Thirty patients with unilateral patello-femoral symptoms and a hypotrophic vastus medialis muscle were treated with transcutaneous electrical stimulation of the vastus medialis obliquus and stretching of the lateral thigh muscles twice daily for 10 weeks. Before and after treatment the position of the patella at fixed knee flexion angles and the area of the vastus medialis and vastus lateralis muscles were studied by computed tomography. Isokinetic quadriceps torque was registered with a Cybex II Dynamometer. An evaluation with a functional knee score was carried out. The healthy contralateral leg served as control in all the examinations. Clinically two-thirds of the patients had improved after 10 weeks of treatment and this improvement remained at follow-up 3.5 years later. The area of the vastus medialis and the quadriceps torque of the treated leg increased significantly, while the area of the vastus lateralis and the position of patella did not change. We conclude that transcutaneous electrical muscle stimulation of the vastus medialis and stretching of the lateral thigh muscles might be of benefit in patients with patello-femoral symptoms and a hypotrophic vastus medialis. An improvement after 10 weeks of treatment seems to predict a good long-term result.