Diagnosis of Knee Osteochondral Lesions With Ultrasound

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2015-09-14

Diagnosis of Knee Osteochondral Lesions With Ultrasound

Penttilä, Pekko

Elsevier BV

info:eu-repo/semantics/article

© Arthroscopy Association of North America

CC BY-NC-ND 4.0 https://creativecommons.org/licenses/by-nc-nd/4.0/

http://dx.doi.org/10.1016/j.eats.2015.04.002

https://erepo.uef.fi/handle/123456789/123

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Diagnosis of Knee Osteochondral Lesions with Ultrasound Imaging

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LEVEL OF EVIDENCE 4

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Abstract

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Evaluation of articular cartilage and subchondral bone is essential in diagnostics of joint diseases

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and injuries. Inter- and intra-observer reproducibilities of arthroscopic grading are only poor to

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moderate. Thus, for quantitative and objective evaluation of cartilage and subchondral bone,

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ultrasound arthroscopy (UA) has been introduced to clarify this dilemma. The clinical feasibility of

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high frequency ultrasound (US) during six knee arthroscopies was conducted and the surgical

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technique is presented. US imaging was conducted with a flexible 9 MHz ultrasound catheter

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inserted into the joint trough conventional portals. US and arthroscopy videos were synchronously

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recorded andUS parameters for cartilage and subchondral bone characteristics were measured.

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Arthroscopy and US imaging were combined in cartilage grading. UA produced quantitative data

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on lesion size, cartilage quality and revealed subchondral bone changes. Visualization of an OCD

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lesion not detected by conventional arthroscopy and US guided retrograde drilling were possible

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with UA. To conclude, UA proved to be clinically feasible and aided diagnostics when assessing

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knee osteochondral lesions.

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Introduction

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Evaluation of articular cartilage and subchondral bone is essential in diagnostics of joint diseases

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and injuries. Currently, diagnostics is based on clinical history, examination, radiographic imaging

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and magnetic resonance imaging (MRI). Diagnosis of cartilage lesions should be immediate,

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sensitive and reproducible to optimize treatment and prevent trauma-initiated osteoarthritis.

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Unfortunately, chondral lesions can sometimes be overlooked by MRI due to suboptimal

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resolution, sensitivity and accuracy (1). Nonetheless, non-traumatic joint diseases, like

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osteochondritis dissecans (OCD), are reported to cause major knee related morbidity, especially

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among adolescents and young adults.

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Numerous surgical techniques have been described for repair of ochondral lesions (2). An

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accurate evaluation, grading and delineation of chondral lesion relative to subchondral bone are

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essential when selecting the appropriate cartilage repair technique.

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Arthroscopic assessment of chondral injuries and stability of OCD is challenging (3), and the inter-

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and intra-observer reproducibilities of grading of cartilage lesions have been reported to be poor,

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especially in the differentiation of intact International Cartilage Research Society (ICRS) 0 from

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softened ICRS 1 cartilage and ICRS 2 from ICRS 3 lesion. (4). An apparent need for more

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objective and quantitative arthroscopic methods has been identified (5).

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Several cartilage measurement instruments, like external US, arthroscopic indentation techniques

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and optical coherence tomography, have been introduced. Quantitative US is reported to detect an

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increase in articular cartilage surface roughness, degradation of superficial collagen, changes in

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subchondral bone mineralization and cartilage healing after surgical repair and this technique is

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recently been applied in human knee arthroscopies (6,7). Ultrasound arthroscopy (UA) is a

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quantitative imaging technique that enables simultaneous visualization of cartilage and

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subchondral bone. The US device, applied in our previous and present publications is approved by

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the Food and Drug Administration (FDA) for human cardiographic imaging.

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Surgical technique

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A standard knee arthroscopy set up is used. The patient is placed supine with the hip flexed at

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about 50° and knee flexed at about 100°. A thigh torniquet is recommended, but not mandatory.

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We prefer a straight operating table with a side post and a foot rest. Both spinal and general

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anesthesia can be used. In addition an ultrasound imaging device with a separate monitor, placed

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near the arthroscopy monitor, is needed making it possible to follow both monitors. Conventional

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portals ( anteromedial and anterolateral) are prepared in the usual way. The arthroscope is

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inserted through the anterolateral portal and diagnostic arthroscopy is performed. Additional portal

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placement (superolateral or -medial, posterolateral or -medial) can be used when needed for the

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UA. Encountered osteochondral pathology is classified according to the International Cartilage

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Repair Society (ICRS) guidelines (1,8). A sterile US imaging catheter is prepared injecting sterile

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saline with a needle into the tip of the 2.8 mm flexible 9 MHz US catheter (diam. 2.8mm,Boston

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Scientific Co, CA, USA). The US device is activated and inserted into the knee joint manually

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through the arthroscopy portal and guided, if needed, within the joint by an arthroscopic half-pipe

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instrument or a hook (Fig. 3). The narrow and flexible catheter can be guided to reach every region

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in the knee joint. Due to the brittle construction of the US catheter, forceful manipulation or pushing

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towards a resistance need to be avoided. Similarly excessive bending of the catheter can cause

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disturbances in the US imaging. US- and arthroscopy can be synchronously recorded. The US

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probe is adjusted manually to achieve perpendicular US incidence at lesion surface in order to

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optimize visualization and to maximize US reflection. In addition to high resolution real time

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imaging, US reflection coefficient (R), integrated reflection coefficient (IRC) and US roughness

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index (URI) are recorded for the cartilage and subchondral bone in normal and pathologic sites of

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the knee (Figs. 1,2,3 and 4). Treatment modalities for each defect are chosen by combining data

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from visual inspection, mechanical probing and US characteristics.

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UA enables quantitative measurement of cartilage lesion depth relative to cartilage thickness

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offering more information for the ICRS grading (Figs. 1, 2, 3 and 4). Normal (ICRS 0) and nearly

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normal (ICRS 1) cartilage showed similar reflection values (R and IRC), providing no additional

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information for the ICRS grading. However, US roughness index was elevated in ICRS 1 cartilage.

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(Fig. 1). A decrease in US reflection (R) was noted between abnormal (ICRS 2) and severely

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abnormal (ICRS 3) cartilage (Fig. 2). On the other hand US roughness index (URI) was increased

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in abnormal cartilage (ICRS 2-3) compared to normal or mildly deteriorated (ICRS 0-1) cartilage.

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High US reflection (R) was seen In ICRS OCD grade 4 lesion with exposed sclerotic bone on the

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bottom of the defect. After debridement and microfracture treatment picking holes could be

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visualized by US (Fig. 4). Moreover, UA enables detection of osteochondral lesions as well as

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measurement of their dimensions. UA is able to detect an OCD lesion with intact articular cartilage

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(pt 5 and 6) (Fig. 3, video). In addition, UA can demonstrate fluid between the bone-cartilage

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interface indicating an unstable OCD lesion necessitating surgical intervention (Fig. 3, Video).

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Even with breeched and lacerated cartilage surface, US allow simultaneous visualization of deeper

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structures reaching the subchondral bone. Furthermore, UA enables the evaluation meniscal

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pathology (Fig. 2). US guided retrograde drilling of ICRS OCD Grade 2 lesion is also possible

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(Video). US enables accurate evaluation of depth and progression of the drilling, avoiding the

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cartilage surface perforation. The use of fluoroscopy can be minimized.

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Discussion

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UA enables imaging and accurate measurements of chondral and osteochondral lesion size, depth

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and quantitative accustic morphology characteristics of cartilage (R, IRC, URI). Every region in a

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knee joint is achievable by UA. Thus, UA proved to be a useful adjunct when assessing and

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treating knee osteochondral lesions.

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Although US imaging was primarily used to confirm the grades obtained by conventional

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arthroscopy, UA lead to a change in the ICRS grade in one out of six patient, where an ICRS OCD

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grade 2 lesion would have been missed by conventional means. The ability of conventional

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arthroscopy to differentiate ICRS 0 from 1 lesions and ICRS 2 from 3 lesions can be challenging.

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Unfortunately the obtained US parameters did not help in the differentiation between these ICRS

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grades. Nevertheless, the differentiation of these groups was possible based on the US images.

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This observation is supported by a recent report demonstrating a significant effect of arthroscopic

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ultrasound imaging on clinical cartilage grading (8). However, the interpretation of the UA images

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was not blinded, which probably composes a potential bias in the interpretation of the UA images.

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No statistically significant variation in the measured US parameters, between lesions of different

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severity, were found. This is due to the limited number of patients with variable cartilage

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conditions.

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Nonetheless, UA provides advantages compared to existing techniques used in knee cartilage

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evaluation and treatment. Conventional arthroscopy enables an evaluation of the superficial

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cartilage by visual and probing characteristics, but no quantitative data. Furthermore, external

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ultrasonography of the knee is suitable only in limited areas requiring an experienced examiner (9).

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To conclude, UA was found to be readily applicable and diagnostically valuable when evaluating

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the integrity of knee articular cartilage. Cartilage thickness and quality may be quantitatively

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assessed providing objective information on the location and extent of lesions. Furthermore, the

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stability and characteristics of OCD lesions can be evaluated with UA. US visualization of

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retrograde drilling in OCD treatment is also possible and, thus, the use of fluoroscopy can be

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minimized. However, further basic and clinical research on this topic is warranted. We expect that

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UA might be a useful adjunct for arthroscopic surgeons in the future.

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References

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1. Reed ME, Villacis DC, Hatch GF 3^rd, Burke WS, Polletti PM, Narvy SJ, Mirzayan R, Vangsness

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CT Jr. 3.0-Tesla MRI and arthroscopy for assessment of knee articular cartilage lesions.

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Orthopedics. 2013 Aug;36(8):e1060-4.

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2. Harris JD, Brophy RH, Siston RA, Flanigan DC. Treatment of chondral defects in the athlete´s

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knee. Arthroscopy. 2010 Jun;26(6):841-52.

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3. Sugita T, Aizawa T, Uozumi H. Can the fragment stability of osteochondritis dissecans be

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interpreted by arthroscopic findings alone? Arthroscopy. 2011 Sep;27(9):1171-2.

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4. Spahn G, Klinger HM, Baums M, Pinkepank U, Hofmann GO. Reliability in arthroscopic grading

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of cartilage lesions: Results of a prospective blinded study for evaluation of inter-observer

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reliability. Arch Orthop Trauma Surg. 2011 Mar;131(3):377-81.

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5. Spahn G, Klinger HM, Hofmann GO. How valid is the arthroscopic diagnosis of cartilage

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lesions? Results of an opinion survey among highly experienced arthroscopic surgeons. Arch

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Orthop Trauma Surg. 2009 Aug;129(8):1117-21.

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6. Nieminen HJ, Zheng YP, Saarakkala S, Wang Q, Toyras J, Huang YP, Jurvelin JS. Quantitative

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Assessment of Articular Cartilage Using High-Frequency Ultrasound: Research Findings and

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Diagnostic Prospects. Crit Rev Biomed Eng. 2009;37(6):461-494.

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7. Kaleva E, Virén T, Saarakkala S, Sahlman J, Sirola J, Puhakka J, Paatela T, Kroger H, Kiviranta

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I, Jurvelin JS, Toyras J. Arthroscopic Ultrasound Assessment of Articular Cartilage in the Human

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Knee Joint: A Potential Diagnostic Method. Cartilage. 2010;2(3):246-253.

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8. Liukkonen J, Lehenkari P, Hirvasniemi J, Joukainen A, Virén T, Saarakkala S, Nieminen MT,

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Jurvelin JS, Toyras J. Ultrasound Arthroscopy of Human Knee Cartilage And Subchondral Bone In

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Vivo. Ultrasound Med Biol. 2014 Sep;40(9):2039-47.

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9. Mathiesen O, Konradsen L, Torp-Pedersen S, Jørgensen U. Ultrasonography and articular

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cartilage defects in the knee: an in vitro evaluation of the accuracy of cartilage thickness and

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defect size assessment. Knee Surg Sports Traumatol Arthrosc. 2004;12:440–3.

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Figure legends

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Figure 1. A still ultrasound arthroscopy image showing normal ICRS 0 (A, B) and nearly normal

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ICRS 1 (C, D) cartilage. Both surfaces profuce similar ultrasound reflection (R) However,

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ultrasound roughness index (URI) is elevated for ICRS 1 compared to ICRS 0 articular cartilage as

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clearly seen in the corresponding arthroscopy images (A, C). P=patella, T=trochlea, R=ultrasound

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reflection coefficient (%), IRC=integraded reflection coefficient (dB), URI=ultrasound roughness index (µm).

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Figure 2. A still ultrasound arthroscopy image demonstrates a decrease in ultrasound reflection (R,

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IRC) and a respective increase in ultrasound roughness index (URI) with progressive cartilage

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degradation as seen in abnormal patellar ICRS 2 (A,B) and severely abnormal femoral ICRS 3

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(C,D) lesions compared to normal cartilage (Fig.1). A concomitant meniscus pathology (encircled

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in red) can be visualized by ultrasound (D). P=patella, T=trochlea, F=femur, Ti=tibia, m=meniscus,

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R=ultrasound reflection coefficient (%), IRC=integrated reflection coefficient (dB), URI=ultrasound roughness index (µm).

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Figure 3. The characteristic subchondral separation (encircled) encountered in osteochondritis

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dissecans (OCD) lesions can be visualized with ultrasound arthroscopy (UA) as gaps of otherwise

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intact subchondral bone signal (A, B). Furthermore, if UA demonstrates fluid beneath the cartilage

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surface, an unstable OCD can be suspected (A, C). F=femur, Ti=tibia, m=meniscus, s=scope artifact,

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sb=subchondral bone, f=fluid, R=ultrasound reflection coefficient (%), IRC=integrated reflection coefficient (dB),

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URI=ultrasound roughness index (µm).

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Figure 4. Ultrasound arthroscopy (UA) demonstrates high reflection and intermediate roughness

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values for exposed sclerotic subchondral bone (A, B). Other subchondral bone changes like

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microfracture picking holes can also be visualized by UA (C, D). F=femur, Ti=tibia, sb=subchondral bone,

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mf=microfracture picking hole, R=ultrasound reflection coefficient (%), IRC=integraded reflection coefficient (dB),

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URI=ultrasound roughness index (µm).

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Video legend

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The principle of arthroscopic ultrasound imaging, and different cartilage lesions in the knee joint

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are shown in simultaneous arthroscopy and ultrasound views. Simultaneous ultrasound and

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arthroscopy videos present the non-invasive evaluation, retrograde drilling and bone

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transplantation for three different osteochondritis dissecans lesions in medial femoral condyle.

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Table 1.

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Table 1. Demographics and results of knee ultrasound arthroscopy patients. LFC=lateral femoral

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condyle, MFC=medial femoral condyle, OCD=osteochondritis dissecans, OA=osteoarthritis, ICRS=International Cartilage

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Repair Society, Gr=grade

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Gender Age (yrs) diagnosis

Age (yrs) surgery

Preoperative Lysholm Knee

Score

Affected knee

Open growth

plates

Extent of the lesion (cm²),

MRI

Location of the lesion

Diagnosis MRI Grade

Ultrasound arthroscopy

Grade

Female 25 25.2 - Right No 0.76 LFC OCD

ICRS OCD Gr IV

ICRS OCD Gr IV

Male 16.4 28.1 80 Right No 3.30 MFC OCD

ICRS OCD Gr III

ICRS OCD Gr III

Male 24.1 24.4 71 Left No 0.17 MFC

Posttraumatic OA, meniscus

defect

ICRS Gr III

ICRS Gr III

Male 37.9 38 72 Right No 0.43 Patella

Patellofemoral OA

ICRS Gr I

ICRS Gr II

Male 12.8 16.3 45 Right Yes 1.79 LFC OCD

ICRS OCD Gr II

ICRS OCD Gr II

Male 10.7 11.4 51 Left Yes 0.40

Both

condyles OCD

ICRS OCD Gr II

ICRSOCD Gr II

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Table 2.

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Advantages, limitations and risks of ultrasound arthroscopy (UA)

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Advantages Limitations and risks

Comprehensive accessibility Not yet validated for cartilage injury classification

Quantitative cartilage measurements

(e.g. cartilage thickness, lesion depth and size, US characteristics)

Costs

(US catheter, measurement device) Accurate cartilage lesion evaluation Marginally prolonged operation time

(5-15 minutes) Accurate osteochondral lesion evaluation

( e.g. intraoperative OCD stability assessment) Radiation free intraoperative monitoring (e.g. cartilage, menisci, subchondral bone) A possibility for US guided procedures (e.g. retrograde OCD drilling)

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