Conventional Radiography Assessment of the Pediatric Knee: Pearls and Pitfalls.

Knee pain is one of the most common indications for radiography in the evaluation of musculoskeletal disorders in children and adolescents. According to international guidelines, knee radiographs should be obtained when there is the suspicion of an effusion, limited motion, pain to palpation, inability to bear weight, mechanical symptoms (such as "locking"), and persistent knee pain after therapy. When indicated, radiographs can provide crucial information for the clinical decision-making process. Because of the developmental changes occurring in the knee during growth, the assessment of knee radiographs can be challenging in children and adolescents. Radiologists unfamiliar with the appearance of the knee on radiographs during skeletal maturation risk overcalling or overlooking bone lesions. Image acquisition techniques and parameters should be adapted to children. This article describes the most common challenges in distinguishing pathology from the normal appearance of knee radiographs in the pediatric population, offering some pearls and pitfalls that can be useful in clinical practice.

Assessing joint health in haemophilia patients: The combined value of physical examination and ultrasound imaging.

INTRODUCTION: Early diagnosis of joint damage is pivotal in haemophilia to prevent the occurrence and progression of haemophilic arthropathy thus providing optimal personalised management. The haemophilia joint health score version 2.1 (HJHS) is based on a physical examination of the mainly affected joints. Musculoskeletal ultrasound has demonstrated the capability to detect early changes in terms of synovitis and osteochondral damage. The haemophilia early detection with ultrasound (HEAD-US) score has been proposed as a simple and reliable evaluation tool. AIM: This study aims to investigate the correlation between the HJHS and the HEAD-US scores performed by two independent operators (physical therapist and musculoskeletal ultrasound expert) for the evaluation of the joint health status of patients with haemophilia. METHODS: Consecutive adult patients independent of the severity degree were included. Elbows, knees and ankles were evaluated by a physical therapist by HJHS and by a musculoskeletal ultrasound expert following the HEAD-US protocol. RESULTS: We observed a good positive correlation between HJHS and HEAD-US (Spearman's rho 0.72). The main discrepancy in conceptually similar domains was found between the HJHS swelling and the HEAD-US synovitis (rho 0.17), as ultrasound was able to detect even mild synovitis when HJHS swelling was scored 0 in up to 40% of cases. CONCLUSIONS: The HJHS and HEAD-US correlate well even when performed by two independent operators. Musculoskeletal ultrasound is particularly useful for the early detection of synovitis. The routine assessment of both scores helps clinicians define the stage and extension of joint involvement and set up a personalised treatment.

Computed tomographic assessment of the completeness of arthroscopic subtotal coronoidectomy in dogs with medial coronoid disease.

BACKGROUND: Until recent years, arthroscopic subtotal coronoidectomy has been the universally accepted treatment for medial coronoid disease but has variable clinical outcomes. The aim of this study was to evaluate the completeness of arthroscopic medial coronoid debridement and to detect the most vulnerable location of failure. METHODS: Eighty-three dogs with a diagnosis of medial coronoid disease were included in the study. Arthroscopic debridement was performed in 92 elbow joints, and the completeness of removal was assessed by postoperative computed tomography scans. RESULTS: Pathological changes were confined to the coronoid apex in 92/92 (100%) of cases and combined with radial incisure lesions in 39/92 (42%). Apical lesions were completely removed in 66/92 (72%) of cases and radial incisure lesions in 2/39 (5%). Bony remnants were detected at the apex (46%) and base (24%) of the medial coronoid process, free within the elbow joint (9%), and/or within the instrument port (84%). Fissures were positively associated with the occurrence of bony remnants (p = 0.038) and a 37% higher probability of incomplete removal of radial incisure lesions (p = 0.001). CONCLUSION: In this study, incomplete removal was more likely to occur in the presence of radial incisure lesions. Thorough assessment of this region during arthroscopy is strongly recommended.

Ultrasound in the assessment of musculoskeletal involvement in systemic lupus erythematosus: state of the art and perspectives.

Musculoskeletal manifestations are extremely common in patients with systemic lupus erythematosus. Transient and migratory arthralgia is frequently reported even without clinical signs of joint or tendon inflammation. In less than 15% of patients, joints may be more severely affected by deforming (Jaccoud's arthropathy) and/or erosive arthropathy (Rhupus syndrome). In recent years, ultrasound has emerged as a promising imaging technique for the assessment of musculoskeletal involvement in systemic lupus erythematosus, having demonstrated the ability to detect inflammation and structural damage both at articular and periarticular level. Recent ultrasound studies have also revealed new insights into musculoskeletal involvement in patients with systemic lupus erythematosus, some of them questioning the traditional concepts of systemic lupus erythematosus arthropathy, with potential clinical, prognostic and therapeutic implications. In daily clinical practice, the use of ultrasound in the assessment of joint and tendon involvement in patients with systemic lupus erythematosus is still limited. Several methodological issues encountered in ultrasound studies evaluating musculoskeletal involvement in systemic lupus erythematosus patients need to be addressed in order to improve both the reliability and clinical usefulness of ultrasound findings. This paper reviews ultrasound studies assessing musculoskeletal involvement in patients with systemic lupus erythematosus, highlighting certainty, limits, potential applications and future perspectives of ultrasound use in systemic lupus erythematosus patients.

Possible evidence for care and treatment in the Tyrolean Iceman.

The Tyrolean Iceman is the world's oldest glacier mummy. He was found in September 1991 in the Italian part of the Ötztal Alps. Since his discovery a variety of morphological, radiological and molecular analyses have been performed that revealed detailed insights into his state of health. Despite the various pathological conditions found in the Iceman, little is known about possible forms of care and treatment during the Copper Age in Northern Italy. A possible approach to this topic is the presence of tattoos on the mummified body. In previous work, it was already believed that the tattoos were administered as a kind of treatment for his lower back pain and degenerative joint disease of his knees, hip and wrist. In other studies, the tattoos of the Iceman have been related to an early form of acupuncture. We carefully re-evaluated the various health issues of the Iceman, including joint diseases, gastrointestinal problems and arterial calcifications and compared them to the location and number of tattoos. Together with the finding of medically effective fungi and plants, such as the birch polypore or fern in his equipment and intestines, we suggest that care and treatment was already common during the Iceman's time.

Radiographic Assessment of the Popliteal Lymph Node to Aid the Differentiation of Canine Stifle Osteosarcoma From Moderate to Severe Stifle Degenerative Joint Disease.

Degenerative joint disease of the stifle is a common canine osseous pathology. Early degenerative changes may show mild mineral proliferation of periarticular margins with soft tissue, resulting in joint distension. If the joint is chronically unstable, osseous changes become more complex. Moderate to severe stifle degenerative disease then transitions to a combination of bony proliferation and resorption as subchondral cystic changes develop. The radiographic descriptions of moderate to severe degenerative disease overlap with those of subtle aggressive disease. If this occurs in a location prone to primary bone tumors, like the distal femur, radiographic interpretation becomes difficult. The aim of this study was to evaluate the utility of objectively assessing the popliteal lymph node size and shape on radiographs to differentiate moderate to severe stifle degenerative joint disease from distal femoral or tibial osteosarcoma. Stifle radiographs were acquired for evaluation of pelvic lameness localized to the stifle joint. Dogs with moderate to severe degenerative stifle joint disease were radiographed at 3 time points: prior to surgery for a tibial plateau leveling osteotomy (103), immediately postoperation (103), and at a recheck 6-8 weeks postsurgery (62). Dogs with osteosarcoma were radiographed only at time of diagnosis (42). Length and width gross popliteal lymph node measurements and a ratio of long axis to short axis were compared between groups using nonparametric analysis. No significant difference was determined using a long axis to short axis ratio for the popliteal lymph node to differentiate moderate to severe stifle degenerative joint disease and osteosarcoma (P = .290). The gross measurements of the long axis and short axis of the popliteal lymph node for dogs with osteosarcoma were significantly greater than the degenerative joint disease groups (P = .017, P = .000). Thus, evaluation of a long axis to short axis ratio for popliteal lymph nodes does not provide a clinically useful objective measure in differentiating peristifle osteosarcoma from moderate to severe degenerative disease of the stifle joint. The length and width of the popliteal lymph node differed significantly; however, the clinical difference is minimal.

Musculoskeletal ultrasonography for arthropathy assessment in patients with hemophilia: A single-center cross-sectional study from Shanxi Province, China.

Magnetic resonance imaging (MRI) is currently considered the gold standard for assessing hemophilic arthropathy (HA) severity; however, MRI is often costly, time-consuming, and difficult to perform in children. In the present study, we evaluated the joint status of hemophilic patients from Shanxi Province, China, using musculoskeletal ultrasonography (MSKUS) and identified the factors that most strongly correlated with disease severity.The study included 104 patients with hemophilia, who underwent MSKUS examination. A total of 1248 joints (including the shoulder, elbow, wrist, hip, knee, and ankle joints on both sides) from these patients were evaluated. Effusion, hypertrophy, cartilage modification, and bone erosion were assessed. The chi-square test was used to analyze categorical variables, and multivariate logistic regression was used to analyze the relationship between joint disease and risk factors.MSKUS allowed clear visualization of synovial lesions, effusion, cartilage modification, and bone surface damage; however, it was unable to identify changes deep within bones. The distribution of damaged joints was as follows: shoulder, 2 (1.0%); elbow, 80 (38.5%); wrist, 4 (1.9%); hip, 4 (1.9%); knee, 126 (60.6%); and ankle, 90 (43.3%). Damage was more common in the knee, elbow, and ankle joints than in the shoulder, wrist, and hip joints (P < .001). Among the 1248 joints, 306 showed lesions, which included effusion in 102 (8.2%) joints, synovium hypertrophy in 176 (14.1%), cartilage modification in 193 (15.5%), and bone damage in 176 (14.1%). Many joints had multiple lesions at the same time. The chi-square test and multivariate logistic analysis showed that age and hemophilia severity were significantly associated with joint disease, while type of hemophilia and treatment categories were not associated with joint disease.MSKUS is a convenient and cost-effective examination that can play an important role in the diagnosis and long-term monitoring of HA.

General Practitioners Referring Adults to MR Imaging for Knee Pain: A Randomized Controlled Trial to Assess Cost-effectiveness.

Purpose To determine the cost-effectiveness of early referral by the general practitioner for magnetic resonance (MR) imaging compared with usual care alone in patients aged 18-45 years with traumatic knee symptoms. Materials and Methods Cost-utility analysis was performed parallel to a prospective multicenter randomized controlled trial in Dutch general practice. A total of 356 patients with traumatic knee symptoms were included from November 2012 to December 2015 (mean age, 33 years ± 8 [standard deviation]; 222 men [62%]). Patients were randomly assigned to usual care (n = 177; MR imaging was not performed, but patients were referred to an orthopedic surgeon when conservative treatment was unsatisfactory) or MR imaging (n = 179) within 2 weeks after injury. Main outcome measures were quality-adjusted life years (QALYs) and costs from a healthcare and societal perspective. Multiple imputation was used for missing data. The Student t test was used to assess differences in mean QALYs, costs, and net benefits. Results Mean QALYs were 0.888 in the MR imaging group and 0.899 in the usual care group (P = .255). Healthcare costs per patient were higher in the MR imaging group (€1109) than in the usual care group (€837) (P = .050), mainly due to higher costs for MR imaging, with no reduction in the number of referrals to an orthopedic surgeon in the MR imaging group. Conclusion MR imaging referral by the general practitioner was not cost-effective in patients with traumatic knee symptoms; in fact, MR imaging led to more healthcare costs, without an improvement in health outcomes.

Comparative Trends in Utilization of MRI and Ultrasound to Evaluate Nonspine Joint Disease 2003 to 2015.

PURPOSE: MRI and ultrasound (US) are effective diagnostic tools to evaluate extremities. In this study, we analyze utilization trends in musculoskeletal (MSK) US and MRI from 2003 to 2015 within the Medicare population. METHODS: Our data sources were the Medicare Part B Physician/Supplier Procedure Summary Master Files for 2003 to 2015. They cover all Medicare fee-for-service enrollees (37.5 million in 2015). Current Procedural Terminology codes for nonvascular, nonspine joint MRI and extremity US were selected and volumes within these codes were determined. Medicare's physician specialty codes were used to identify provider specialty. We accounted for the 2011 code change that created both complete and limited US examinations. RESULTS: Total Medicare joint MRI volume increased from 738,509 in 2003 to 1,131,503 in 2015 (+53%), although there was little change after 2007. Radiologist MRI share in 2015 was 93%, followed by orthopedic surgeons at 5%. Total MSK US volume grew from 96,235 in 2003 to 429,695 in 2015 (+347%). Radiologists' market share of US decreased from 65% in 2003 to 37% in 2015, with nonradiologists now representing a majority of ultrasound examinations. Multiple nonradiology subspecialties also exceed radiology in volume of complete ultrasounds. CONCLUSION: The potential negative impact of MSK US on MSK MRI volume is likely overestimated because MRI volume has remained stable. MSK ultrasound is increasingly utilized outside radiology. If radiologists want to maintain their market share as MSK imaging leaders, more emphasis should be placed on increasing their involvement and expertise in MSK US.

The validity and accuracy of MRI arthrogram in the assessment of painful articular disorders of the hip.

The assessment of a patient with chronic hip pain can be challenging. The differential diagnosis of intra-articular pathology causing hip pain can be diverse. These includes conditions such as osteoarthritis, fracture, and avascular necrosis, synovitis, loose bodies, labral tears, articular pathology and, femoro-acetabular impingement. Magnetic resonance imaging (MRI) arthrography of the hip has been widely used now for diagnosis of articular pathology of the hip. A retrospective analysis of 113 patients who had MRI arthrogram and who underwent hip arthroscopy was included in the study. The MRI arthrogram was performed using gadolinium injection and reported by a single radiologist. The findings were then compared to that found on arthroscopy. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy and 95% confidence interval were calculated for each pathology. Labral tear-sensitivity 84% (74.3-90.5), specificity 64% (40.7-82.8), PPV 91% (82.1-95.8), NPV 48% (29.5-67.5), accuracy 80%. Delamination -sensitivity 7% (0.8-22.1), specificity 98% (91.6-99.7), PPV 50% (6.8-93.2), NPV 74% (65.1-82.2) and accuracy 39%. Chondral changes-sensitivity 25% (13.3-38.9), specificity 83% (71.3-91.1), PPV 52% (30.6-73.2), NPV 59% (48.0-69.2) and accuracy 58%. Femoro-acetabular impingement (CAM deformity)-sensitivity 34% (19.6-51.4), specificity 83% (72.2-90.4), PPV 50% (29.9-70.1), NPV 71% (60.6-80.5) and accuracy 66%. Synovitis-sensitivity 11% (2.3-28.2), specificity 99% (93.6-100), PPV 75% (19.4-99.4), NPV 77% (68.1-84.6) and accuracy 77%. Our study conclusions are MRI arthrogram is a useful investigation tool in detecting labral tears, it is also helpful in the diagnosis of femoro-acetabular impingement. However, when it comes to the diagnosis of chondral changes, defects and cartilage delamination, the sensitivity and accuracy are low.

Radiographic assessment of humeroulnar congruity in a medium and a large breed of dog.

Elbow joint incongruity is recognized as an important factor in the development, treatment, and prognosis of canine elbow dysplasia. Elbow incongruity has been measured based on radiographic joint space widths, however these values can be affected by the degree of elbow joint flexion. Recent studies have reported radiographic curvature radii as more precise measures of humeroulnar congruity in dogs. The aim of this prospective observational study was to describe radiographic curvature radii measured from flexed and extended elbow radiographs for a sample of dogs representing a medium breed (Portuguese Pointing Dog) and a large breed (Estrela Mountain Dog). The curvature radii from the ulnar trochlear notch and humeral trochlea were measured in 114 mediolateral elbow extended radiographic views (30 Portuguese Pointing Dog and 27 Estrela Mountain Dog), and 84 mediolateral flexed views (22 Portuguese Pointing Dog and 20 Estrela Mountain Dog). The sampled animals' ages ranged from 12 to 84 months (34.6 ± 17.8 months). Good agreement was observed between curvature radii measurements for flexed vs. extended views in both breed groups. Ulnar trochlear notch curvature radii measurements were greater than humeral trochlea curvature radii measurements in both breed groups. Both curvature radii were greater in the large-breed dog group vs. the medium-breed dog group. Both breed groups had ulnar and humeral curves with similar typology. However, the large breed group had greater intermediate differences between the humeroulnar surface curvature radii. Results from this study supported the use of curvature radii as measures of humeroulnar congruity in mediolateral flexed elbow radiographs of medium and large breed dogs.

The risk assessment of pathological fracture in the proximal femur using a CT-based finite element method.

BACKGROUND: Patients who have lytic bone lesions in their proximal femurs are at risk for pathological fracture. Lesions with high fracture risk are surgically treated using prophylactic osteosynthesis, whereas low-risk lesions are treated conservatively. However, it is difficult to discriminate between high- and low-risk lesions based on clinical and radiographic findings. The computed tomography (CT)-based finite element (FE) models are useful for predicting the fracture load on proximal femoral lytic lesions. MATERIALS AND METHODS: FE models were constructed from the quantitative CT scans of the femurs using software that created individual bone shapes and density distributions. Three independent observers measured the lesion size, Mirels' score, and thickness of the proximal femur along the horizontal plane. The predictive risk values of the proximal femur measured using the CT-based FE analysis were statistically compared. RESULTS: The patients were divided into two groups (high and low risk). The mean fracture load was significantly higher in the high-risk group than in the low-risk group (5395 ± 525 N, 2622 ± 364 N, respectively, p = 0.0003). No significant differences in age, body weight, lesion size or Mirels' score were observed between groups. However, the thickness of the medial cortex in the high-risk group according to the FE analysis was significantly thinner than that in the low-risk group. Furthermore, the medial cortex thickness was positively correlated with the predicted fracture load. An optimal cut-off value of 3.67 mm for the thickness of the inner cortex resulted in 100% sensitivity and 75.1% specificity values for classifying the patients based on their fracture risk. CONCLUSIONS: Our findings indicate that the FE method is useful for the prediction of the pathological fracture. This method shows a versatile potential for the prediction of pathological fracture and might aid in judging the optimal treatment to prevent fracture.

Assessment of anterior subcutaneous hypersignal on proton-density-weighted MR imaging of the knee and relationship with anterior knee pain.

PURPOSE: The purpose of this study was to evaluate the prevalence of anterior subcutaneous hypersignal indicating edema on proton-density (PD)-weighted MRI of the knee and to determine whether reporting anterior edema is clinically relevant. MATERIALS AND METHODS: One hundred and ninety-one knee MRIs from 162 patients were reviewed for anterior subcutaneous edema. There were 92 men and 70 women with a mean age of 41.72years±13.92 (SD) (range, 15-80years) years and a mean body weight of 75.94kg±12.54 (SD) (range, 50-130kg). The MRI findings were compared with patient age, gender, body weight, history of repetitive microtrauma and clinical findings. Patellar and trochlear chondropathy, medial plica, joint effusion, synovitis, infrapatellar fat-pad signal intensity, suprapatellar fat-pad signal intensity with mass effect, quadriceps and patellar tendon abnormalities were also reviewed. RESULTS: An anterior hypersignal on PD-weighted MRI was detected in 158/191 MR examinations (82.7%) and 104 (84.6%) of these cases had histories of anterior knee pain. No correlation between anterior pain and anterior edema was found (P=0.42). Age (P<0.0001), weight (P<0.0001), and repetitive microtrauma (P=0.001) were identified as significant variables associated with anterior edema. CONCLUSION: Anterior edema may be a physiological phenomenon or degenerative change related to patient age, weight, and knee movement or mechanics. It should not be reported as a pathological finding on MRI unless clinical findings support regional infection or inflammation.

The Genovese grading scale is not reliable for MR assessment of collagen meniscus implants.

BACKGROUND: The purpose of the study was to evaluate the intra- and inter-observer reliabilities of the Genovese grading on MRI in patients after collagen meniscus substitution. METHODS: 84 MRI images of 74 consecutive patients who underwent partial meniscus substitution using collagen meniscus implant (CMI) were assessed. MRIs were evaluated using the Genovese grading system. Furthermore, meniscal extrusion was assessed. Two observers performed the grading twice, blinded to each other and to the previous results, with a six weeks interval. The inter- and intra-observer reliabilities were assessed using kappa and weighted kappa values. RESULTS: The criterion "morphology/size" showed a weighted kappa value inter-observer reliability of 0.069 (rater 1)/0.352 (rater 2) and intra-observer reliability of 0.170 (1st rating)/0.582 (2nd rating). The criterion "signal intensity" showed a weighted kappa value inter-observer reliability of 0.175/0.284 and intra-observer reliability of 0.294/0.458. The criterion "cartilage lesions" showed a kappa value inter-observer reliability of 0.091/0.525 and intra-observer reliability of 0.409/0.413. The criterion "bone marrow edema" showed a kappa value inter-observer reliability of 0.667/0.808 and intra-observer reliability of 0.702/0.715. The criterion "cartilage lesions" showed a kappa value inter-observer reliability of 0.091/0.525 and intra-observer reliability of 0.409/0.413. Regarding meniscal extrusion kappa values for the inter-observer reliability were 0.625/0.940 and 0.625/0.889 for intra-observer reliability. CONCLUSIONS: Three of the four Genovese grading items showed only slight to moderate inter- and intra-observer reliabilities in evaluating CMI on MRI. Hence, such grading results need to be considered with all due care. Only the criteria "bone marrow edema" and "meniscal extrusion" showed a good agreement for both inter- and intra-observer reliabilities.

Knee ultrasound from research to real practice: a systematic literature review of adult knee ultrasound assessment feasibility studies.

OBJECTIVE: To identify and analyse existing data regarding knee ultrasound (US) feasibility in clinical practice. Material and methods: A systematic literature review was performed using the terms: ("knee") AND ("ultrasound" OR "ultrasonography") AND ("feasibility" OR "pilot" OR "proof of concept"). Feasibility studies regarding knee US or US aided maneuver involving knee joint, published during 2005-2015, were selected and evaluated against a complex framework constructed around mandatory key areas for feasibility studies: acceptability, demand, implementation, practicality, adaptation, integration and expansion. RESULTS: One hundred and fifty-nine publications were identified, of which 9 were included in the final analysis: 6 dealt with the development and implementation of novel US scores, while the rest focused on implementing MSUS in clinical practice, evaluating the usefulness of articular cartilage US assessment and the feasibility of sonography for intra-articular knee injections, respectively. Six studies quantified feasibility as time spent for the evaluation, with only two addressing areassuch as acceptability, implementation and practicality, although none of these systematically assessed all feasibility domains. CONCLUSION: Knee US feasibility is still poorly addressed; the time required for US assessment is the main area addressed. This information gap should be properly addressed in future works, in order to ensure the right place for this technique.

Correlating clinical and radiological assessment of joints in haemophilia: results of a cross sectional study.

OBJECTIVES: This study was undertaken to determine the correlation between the radiological changes in haemophilic arthropathy [X-ray, Ultrasound (US) and MRI] and clinical assessment as determined by the Hemophilia Joint Health Score (HJHS); and to document the US and MRI changes in joints that appear normal on plain X-ray and clinical evaluation. MATERIALS AND METHODS: Of 55 study joints (22 knees and 33 ankles) in 51 patients with haemophilia/von Willebrand disease, with a median age of 15 years (range: 5-17) were assessed using X-rays (Pettersson score) and clinical examination (HJHS) at two centres (Toronto, Canada; Vellore, India). MRI and ultrasonographic scoring was done through a consensus assessment by imagers at both centres using the IPSG MRI and US scores. RESULTS: The HJHS had a good correlation with the Pettersson score (rs = 0.66). Though the HJHS had moderate correlation with the osteochondral component of the MRI and US scores (rs 0.51, 0.45 respectively), its correlation with the soft tissue component was poor (rs 0.19; 0.26 respectively). Of the 18 joints with a Pettersson score of zero, 88.9% had changes that were detected clinically by the HJHS. Osteochondral abnormalities were identified in 38.9% of these joints by the MRI, while US images of the same joints were deemed abnormal in 83.3% by the current criteria. US identified haemosiderin and other soft tissue changes in all of the joints, while the same changes were noted in 94.4% of these joints on MRI. There were four joints with a HJHS of zero, all of which had soft tissue changes on MRI (score 1-7) and US (score 2-7). Osteochondral changes were detected in three of these joints by US and in 2 by MRI. There were four joints with an MRI score of 0-1 that had significant US scores (3-5) and HJHS scores (0-6). CONCLUSION: US and MRI are able to identify pathological changes in joints with normal X-ray imaging and clinical examination. However, further studies are required to be able to differentiate early abnormalities from normal. Clinical (HJHS) and radiological assessment (US/MRI) provide complimentary information and should be considered conjointly in the assessment of early joint arthropathy.

Assessment of trunk muscle density using CT and its association with degenerative disc and facet joint disease of the lumbar spine.

OBJECTIVE: The purpose of this study was (1) to evaluate the association of trunk muscle density assessed by computed tomography (CT) with age, gender, and BMI and (2) to evaluate the association between trunk muscle CT density and degenerative disc and facet joint disease of the lumbar spine. MATERIAL AND METHODS: The study was IRB approved and HIPAA compliant. The study group comprised 100 subjects (mean age 44.4 ± 22.2 years, 51 % male) who underwent CT of the abdomen and pelvis without intravenous contrast. Exclusion criteria included prior abdominal or spine surgery, active malignancy and scoliosis. CTs were reviewed and the attenuation of the rectus abdominis, transverse abdominis, internal and external obliques, psoas, multifidus, longissimus and gluteus maximus were measured bilaterally at consistent levels. Degenerative disc and bilateral facet joint disease were scored using established methods. Univariate analyses were performed using linear regression. Multivariate linear regression was performed to adjust for age, gender and BMI. RESULTS: CT density of each trunk muscle correlated inversely with age (p < 0.001) and BMI (p < 0.001). CT density of each trunk muscle correlated inversely with degenerative disc and facet joint disease in the univariate analyses (p < 0.001); however, only the gluteus maximus and the transverse abdominis remained significant predictors of degenerative disc and facet joint disease respectively in the multivariate analysis. CONCLUSION: Fatty infiltration of trunk musculature increases with age and BMI. Fatty infiltration of the gluteus maximus and transverse abdominis are associated with degenerative disc and facet joint disease, independent of age, gender and BMI.