Osteoarthritis





KEY POINTS




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    Ultrasound is able to detect most elementary lesions involving bony cortex and soft tissues in osteoarthritis (OA).


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    Ultrasound demonstrates both the inflammatory changes and structural damage lesions in OA.


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    Ultrasound is useful in providing guidance for local procedures in OA.


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    Ultrasound facilitates monitoring of disease progression of OA and follow-up assessment of the response to treatment.



Until recently, the interest of scientists operating in the field of musculoskeletal ultrasound in rheumatology has mainly focused on the study of inflammatory diseases and on the assessment of regional pain syndromes. However, investigators are becoming interested in the application of ultrasound for evaluating osteoarthritis, and many published studies demonstrate the increasing appeal of these tools.


Osteoarthritis is the most common rheumatic disease affecting peripheral and axial synovial joints. All articular tissues have dysregulation of local turnover and repair processes and consequent joint failure. Pathologic aspects are represented by focal degeneration and progressive loss of cartilage and hypertrophy of the subchondral bone, joint margin, and capsule. Some degree of synovitis exists, with an episodic course that can contribute to worsening symptoms and cartilage deterioration. Nondestructive synovial proliferation, joint effusion, and bursitis are frequent findings in osteoarthritis. Mostly elderly people are affected by the disease, although it can occur relatively early in life, causing disability and work impairment. Joint use-related pain, swelling, stiffness, deformity, and loss of joint motion are the most common clinical features of the disease that frequently cause patients’ complaints and relevant public health problems.


Osteoarthritis usually has been imaged by using standard plain radiography, which has been a valuable tool for diagnosing and quantifying most changes that occur in the course of the disease. For those reasons, it has been regarded as the initial and standard technique for imaging osteoarthritis. The typical radiologic findings are represented by joint space narrowing, osteophytes, sclerosis, and deformity. However, there are limitations in directly visualizing cartilage, in demonstrating minor cartilaginous changes, and in showing frequent concomitant soft tissue involvement. Moreover, it is unclear whether changes demonstrated by this tool are real features of the disease, because they may occur only after long disease duration and are sometimes evident in elderly but asymptomatic people. Consequently, there is unanimous consensus in the medical community about the necessity to have a reliable, valid, and reproducible tool to study and evaluate distinct changes occurring in osteoarthritis.




Ultrasound in Osteoarthritis


Ultrasound can demonstrate and quantify a series of changes occurring in cartilage ( Fig. 14-1 ), in other soft tissue of the joint, and in periarticular areas. It seems to have been a neglected imaging tool in osteoarthritis until recently, but interest is emerging in the application of ultrasound for imaging and investigating early and late changes in osteoarthritis ( Figs. 14-2 and 14-3 ). It complements clinical evaluation of osteoarthritis and can bridge the gap between clinical and radiologic findings. It can be easily and quickly performed in the same room used for the physical examination, reducing the patient’s discomfort.




F igure 14-1


Ultrasound shows the femoral condylar hyaline cartilage. A, The anterior transverse scan of the suprapatellar area is performed with the patient in the supine position and the joint fully flexed. B, A 10-MHz ultrasound image shows normal cartilage appearing as a curvilinear band. Notice the typical anechoic and homogeneous echotexture of the cartilage lining the bony profile and having two sharp, continuous, and regular hyperechoic margins. The anterior margin is sharper and thinner than the deeper surface, which is more echoic and thicker and represents the interface between the cartilage and the bony profile. Because of the high water content, the hyaline cartilage has a well-defined, anechoic structure lacking internal echoes. C, A 10-MHz ultrasound image depicts osteoarthritic cartilage. Notice the irregularity of the superficial and deep margins, the asymmetric narrowing, and the loss of homogeneity and transparency.



F igure 14-2


Anterior transverse scans in the suprapatellar area reveal the femoral condylar hyaline cartilage in a patient with osteoarthritis. A-D, The 10-MHz ultrasound images demonstrate progression of cartilage lesions, represented by blurring and irregularities of the superficial and deep interfaces with loss of their normal sharpness; changes in the echogenicity, with typical loss of homogeneity and transparency; and progressive thinning of the cartilage up to complete absence of the cartilaginous layer due to cartilage breakdown and bony denudation.



F igure 14-3


Anterior longitudinal scans are used to evaluate the hyaline cartilage of the second metacarpal head in a patient with osteoarthritis. A-D, The 15-MHz ultrasound images demonstrate progressive alterations characterized by loss of sharpness and blurring of the superficial and deep edges, changes in the echotexture with a hypoechoic appearance, and progressive cartilage thinning.


Ultrasound facilitates monitoring of disease progression (see Figs. 14-2 and 14-3 ) and follow-up assessment of the response to local and systemic treatments for osteoarthritis; the ultrasound examination can be repeated as many times as necessary. Sonography consists of direct and multiplanar evaluation of distinct musculoskeletal districts and most peripheral joints involved by the disease. These features allow imaging of many soft tissues, such as hyaline cartilage ( Fig. 14-4 ; see Figs. 14-1 to 14-3 ); synovial membrane and fluid ( Figs. 14-5 to 14-13 ); joint capsule, tendons, ligaments, and bursae ( Figs. 14-14 and 14-15 ; see Fig. 14-13 ); and external areas of menisci ( Fig. 14-16 ). Ultrasound can detect cortical bone alterations and demonstrate the typical structural changes of the disease ( Figs. 14-17 to 14-24 ). Its usefulness in providing guidance for local procedures has been extensively confirmed in studies that have shown its reliability in imaging correct positions (see Fig. 14-15 ) and the progress of needles used for local aspiration, drug injection, and biopsy of joints and periarticular soft tissues. All of these procedures are performed safely and are well tolerated by patients when executed under the sonographic guidance.




F igure 14-4


A, Ultrasound is used to evaluate the femoral condylar hyaline cartilage in a patient with knee osteoarthritis and varus deformity. B and C, The 12-MHz ultrasound images of the right and left knees demonstrate evident loss of sharpness and irregularities of the superficial and deep margins, asymmetric cartilage thinning, and changes in the anechoic echotexture.



F igure 14-5


Ultrasound is used to assess the first carpometacarpal joint in a patient with hand osteoarthritis. A, The gray-scale, longitudinal, 15-MHz image of the joint demonstrates a joint effusion (star) , synovial hypertrophy, and osteophytes (arrows) B, Power Doppler technique shows increased perfusion within the synovial tissue due to active inflammation.



F igure 14-6


Ultrasound is used to assess the parapatellar recesses in the knee joint of a patient with osteoarthritis. A-D, The 12-MHz ultrasound images show various degrees of joint effusion (stars) and synovial proliferation (arrows) , which assumes the aspect of polymorphous vegetations with characteristic polypoid or cauliflower-like morphology.



F igure 14-7


Power Doppler ultrasound is used to evaluate the parapatellar recesses in the knee joint of a patient with osteoarthritis. Ultrasound images show mildly ( A ) and moderately ( B ) increased vascularization within the thickened synovial membrane, indicative of active inflammatory processes.



F igure 14-8


Power Doppler ultrasound shows the suprapatellar and parapatellar recesses in the knee of a patient with osteoarthritis. Mild ( A and B ) and moderate ( C and D) hyperperfusion indicates active inflammation.



F igure 14-9


Ultrasound demonstrates the hip ( A ) and elbow ( B ) joints in patients with osteoarthritis. The 12-MHz ultrasound images show joint effusion (X), synovial thickening (stars) that determines joint capsule distention (arrows) , and osteophytes (arrowhead) . AC, acetabulum; FH, femoral head; FN, femoral neck.



F igure 14-10


A, Ultrasound is used to examine the hands of a patient with osteoarthritis and inflammation of Heberden’s nodes. B and C, Power Doppler confirms active inflammation in the distal interphalangeal joints by demonstration of an intra-articular Doppler signal due to hyperemic phenomena within the local synovial membrane.



F igure 14-11


A, Ultrasound is used to assess the hands of a patient with osteoarthritis and inflammation of Bouchard’s nodes. B, Power Doppler shows local inflammation involving the proximal interphalangeal joints due to synovial hyperemic phenomena.



F igure 14-12


Ultrasound of a foot with osteoarthritis shows involvement of the first metatarsophalangeal joint. A and B, The 15-MHz images demonstrate synovial proliferation (stars) and osteophytes (arrow) . C and D, Local active inflammation is demonstrated by the detection of a moderate intra-articular power Doppler signal. MH, metatarsal head; PP, proximal phalanx.



F igure 14-13


Ultrasound shows various aspects of foot involvement by osteoarthritis. A, The 15-MHz image shows involvement of the first metatarsophalangeal joint and synovial proliferation (star) . B, Power Doppler demonstrates active inflammation within the talonavicular joint by the detection of an intra-articular signal. C, The 15-MHz image demonstrates bursitis (arrows) over the medial aspect of the first metatarsophalangeal joint. MH, metatarsal head; PP, proximal phalanx.



F igure 14-14


Ultrasound is used to evaluate the calf in patients with knee osteoarthritis and calf swelling. A-D, The 12-MHz images show Baker’s cysts having mixed contents of local effusion (stars) , synovial thickening and proliferation (X), and internal calcifications (thick arrow) , causing distention of the bursal wall ( thin arrow in D ).



F igure 14-15


Ultrasound demonstrates large Baker’s cysts in patients with knee osteoarthritis. A and B , The 12-MHz images depict Baker’s cysts with various contents; local effusion (X) and synovial proliferation (stars) are shown. The image in A offers an extended-view reconstruction of the calf. In B the needle (arrows) used for guided local injection is seen.



F igure 14-16


The 12-MHz longitudinal scan over the medial aspect of a knee joint with osteoarthritis shows large osteophytes (down arrows) and protrusion of the medial meniscus (up arrow) that determines displacement of the medial collateral ligaments. F, femur; T, tibia.



F igure 14-17


Ultrasound is used to assess an acromioclavicular joint with osteoarthritis. A-F, The 12-MHz longitudinal scan over the superior aspect of the joint shows various aspects of joint involvement, including osteophytes (arrows) , joint subluxation (arrowhead) , joint effusion (stars) , and synovial thickening (X).



F igure 14-18


Ultrasound demonstrates an acromioclavicular joint with osteoarthritis. The 12-MHz longitudinal scan over the superior aspect of the joint shows an osteophyte (white arrow) and joint capsule thickening (black arrows) .



F igure 14-19


An osteoarthritic knee is assessed with ultrasound. The 12-MHz longitudinal scan over the medial aspect of the joint shows large osteophytes (white arrows) and displacement of the medial collateral ligaments (black arrows) . F, femur; T, tibia.

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Mar 1, 2019 | Posted by in RHEUMATOLOGY | Comments Off on Osteoarthritis

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