Ovid: Musculoskeletal Imaging Companion

Editors: Berquist, Thomas H.
Title: Musculoskeletal Imaging Companion, 2nd Edition
> Table of Contents > Chapter 5 – Knee

Chapter 5
Thomas H. Berquist
  • Radiographs or computed radiography images
    • Routine images
    • Anteroposterior (AP) and lateral (minimum two views)
    • Trauma
    • AP, lateral (cross-table preferred to detect lipohemarthrosis), both obliques
    • Patella
    • Lateral and tangential (sunrise) views
    • Orthopedic series
    • AP standing, AP standing with flexion, lateral, and patellar views
    • Additional techniques
      • Notch views
      • Stress views (varus, valgus, AP)
  • P.211

  • Computed tomography (CT)
    • Helical CT images at 1-mm thick sections at 0.5-mm intervals (can be reformatted in the coronal and sagittal planes)
    • Bone and soft tissue window settings
  • Magnetic resonance imaging (MRI) (Table 5-1)
    • Extremity coil, knee slightly flexed (5 to 10 degrees)
Image Plane Sequence Slice thickness/Skip FOV Matrix Acquisitions
Scout localizer FLASH 15/5 8 mm/8 mm 14 256 × 128 1
Coronal T1 SE 689/14 4 mm/0.5 mm 14 512 × 256 2
Coronal DESS DE 23.8/6.7 1 mm/0.2 mm 14 256 × 192 2
Sagittal PD FSE 2500/26 echo train 7 4 mm/0.5 mm 14 512 × 256 2
Sagittal T2 FSE 4000/83 echo train 7 4 mm/0.5 mm 14 512 × 256 2
Axial PD FSE 4000/26 echo train 7 4 mm/0.5 mm 14 256 × 192 2
Skeletal Trauma: Osteochondral Fractures


Patellar view demonstrating subluxation after reduction of a patellar
dislocation. There is a displaced osteochondral fragment (arrow) laterally.
Suggested Reading
Capps GW, Hayes CW. Easily missed injuries about the knee. Radiographics 1994;14:1191–1210.
Dezell PB, Schils JP, Recht MP. Subtle fractures about the knee: Innocuous appearing yet indicative of internal derangement. AJR Am J Roentgenol 1996;167:699–703.


Skeletal Trauma: Patellar Fractures
FIGURE 5-2 AP (A) and lateral (B) radiographs of a bipartite patella (arrow).


FIGURE 5-3 AP (A) and lateral (B) radiographs of a comminuted displaced patellar fracture.


FIGURE 5-4 Lateral (A) and patellar (B) views after reduction with K-wires and tension band. The articular surface is reduced.
Suggested Reading
Bostrom A. Fracture of the patella. Acta Orthop Scand Suppl 1972;143:1–80.


Skeletal Trauma: Supracondylar Fractures

Early Late
Vascular injury Infection
Infection Nonunion
   1% of closed Malunion
   20% of open Osteoarthritis
Failed reduction  



FIGURE 5-5 Orthopedic Trauma Association Classification. Type A: extra-articular, simple (A) or comminuted (B) Type B: partial articular, one condyle involved (C) Type C: complete articular, both condyles involved with “Y” pattern (D) or (E).


FIGURE 5-6 AP (A) and lateral (B) radiographs of a severely comminuted complete articular fracture. Note the loss of length and posterior rotation (arrow) of the distal fragment in (B).


Ipsilateral fractures of the tibia, fibula, and femur. Type I: tibial
and femoral fractures without knee involvement (71% of cases). Type
IIA: femoral fracture with tibial articular involvement (16.5% of
cases). Type IIB: femoral articular involvement and proximal tibia and
fibular fractures. Type IIC: both articular surfaces involved (8% of
Suggested Reading
Fraser RD, Hunter GA, Waddle JP. Ipsilateral fractures of the femur and tibia. J Bone Joint Surg 1978;60B:510–515.
O’Brien P, Meek RN, Blachut PA, et al. Fractures of the distal femur. In: Bucholz RW, Heckman JD, eds. Rockwood and Green’s fractures in adults. 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2001:1731–1773.
Orthopedic Trauma Association Committee on Coding and Classifications. Fractures and dislocations compendium. J Orthop Trauma 1996;10(suppl):41–45.


Skeletal Trauma: Proximal Tibial Fractures
Hohl classification of tibial plateau fractures: I, undisplaced
fracture (24%); II, central depression (26%); III, split compression,
usually with fibular fracture (29%); IV, total condylar depression
(11%); V, comminuted bicondylar fractures (10%).


FIGURE 5-9 (A) Tibial plateau fracture with splitting and separation laterally. (B) Tibial plateau fracture reduced with buttress plate and screws to restore joint congruency.


FIGURE 5-10 CT images in the axial (A), sagittal (B), and coronal (C) planes demonstrating a minimally depressed fracture (arrows) with minimal articular displacement (open arrow).
Suggested Reading
Hohl M. Tibial condylar fractures. J Bone Joint Surg 1967;49A:1455–1467.


Skeletal Trauma: Miscellaneous Fractures
FIGURE 5-11 Ligament support about the knee. (A) The tibial physis is within the ligament support, and the femoral physis is proximal resulting in greater risk for fracture (B,C).


FIGURE 5-12 AP (A), lateral (B), and stress views (C) of a Salter-Harris III femoral fracture.


FIGURE 5-13 AP radiograph of a Segond fracture (arrow).


FIGURE 5-14 Lateral radiograph of a tibial tuberosity avulsion.


FIGURE 5-15 Tibial spine–ACL avulsion. AP (A) and lateral (B) radiographs demonstrate a joint effusion (open arrows) and subtle bone fragment (arrow) in the joint space. Coronal double-echo steady state (C) and sagittal T2-weighted (D) MR images demonstrate the ACL avulsion (arrow).


FIGURE 5-16 Cross-table lateral radiograph demonstrating a lipohemarthrosis (arrows) indicating an intra-articular fracture.
FIGURE 5-17 (A) AP radiograph is normal. (B) Coronal T1-weighted image clearly demonstrates the stress fracture (arrow).


FIGURE 5-18 Bone bruise (arrow) clearly demonstrated on the sagittal T2-weighted (A) and coronal T1-weighted (B) MR images. Note the abnormal medial collateral ligament (MCL) (white arrow in B) resulting from valgus injury.
Suggested Reading
Dezell PB, Schils JP, Recht MP. Subtle fractures about the knee: Innocuous-appearing yet indicative of internal derangement. AJR Am J Roentgenol 1996;167:699–703.


Meniscal Lesions: Meniscal Tears


Meniscal appearance (medial and lateral) with the knee in different
degrees of rotation. Note the posterior horn of the medial meniscus (arrow) is larger. The popliteus tendon sheath (pt) separates the lateral meniscus from the capsule posteriorly.


FIGURE 5-20 (A) Types and appearances of meniscal tears. (B) Meniscal tears seen in the axial and coronal planes.


MR classification of meniscal tears. Normal-low signal intensity. Grade
1: globular increased signal intensity that does not communicate with
the articular surface. Grade 2: linear increased signal intensity that
does not communicate with the articular surface. Grade 3: linear
increased signal intensity that communicates with the articular
surface, a true tear. Grade 3a and b: more extensive articular
involvement. Grade 4: complex tears with distortion of the meniscus.
FIGURE 5-22 Sagittal proton density-weighted image of a normal low-intensity meniscus.


FIGURE 5-23 Gradient-echo sagittal image of a linear tear (arrowheads) in the posterior medial meniscus.


FIGURE 5-24 Coronal fat-suppressed T2-weighted image of a bucket-handle tear of the medial meniscus. Note truncated meniscus (arrow) and displaced fragment (open arrow) giving a “double posterior cruciate ligament (PCL)” sign. There is also a complex tear of the lateral meniscus (small arrow).


FIGURE 5-25 Axial (A) and sagittal (B) illustrations of a flipped meniscal fragment. Posterior (C) and anterior (D) coronal proton density-weighted images demonstrate a small posterior meniscal remnant (arrow) and a large meniscus anteriorly (arrows). Compare with the normal medial meniscus. Sagittal image (E) shows a large anterior horn and no posterior horn.


Suggested Reading
GB, Majors NM, Helms CA. Comparison of fast spin-echo versus
conventional spin-echo MRI for evaluation of meniscal tears. AJR Am J Roentgenol 2005;184:1740–1743.
Crues JV III, Murk J, Levy TL, et al. Meniscal tears of the knee: Accuracy of MR imaging. Radiology 1987;164:445–448.
Harper KW, Helms CA, Lambert HS III, et al. Radial meniscal tears: Significance, incidence, and MR appearance. AJR Am J Roentgenol 2005;185:1429–1434.
DH, Desmet AA, Norres M. Bucket-handle tears of the medial and lateral
menisci of the knee: Value of MR imaging in detecting displaced
fragments. AJR Am J Roentgenol 1995;165:621–625.


Meniscal Lesions: Postoperative Meniscus
FIGURE 5-26 (A) Sagittal MR image of a normal medial meniscus. (B) Partial meniscectomy and peripheral repair. There is increased signal in the region of the repair (arrow). The central meniscus appears normal. (C) Sagittal T2-weighted image after complete meniscectomy (arrow).


Suggested Reading
Lum PS, Schweitzer ME, Bhatea M, et al. Repeat tear of postoperative meniscus: Potential MR imaging signs. Radiology 1999;210:183–188.
Magee TH, Shapiro M, Rodriguez J, et al. MR arthrography of the postoperative knee: For which patients is it useful? Radiology 2003;229:159–163.


Meniscal Lesions: Meniscal Cysts
FIGURE 5-27 Meniscal cysts. (A) Small posteromedial meniscal cyst (arrow) seen on a sagittal T2-weighted image. The meniscal tear is not well seen on this sequence. (B) Coronal T2-weighted image demonstrating a large septated meniscal cyst (arrow).
Suggested Reading
Burk DL, Dalinka MK, Kanal E, et al. Meniscal and ganglion cysts of the knee. MR evaluation. AJR Am J Roentgenol 1988;150:331–336.
Campbell SE, Sanders TG, Morrison WB. MR imaging of meniscal cysts: Incidence, location, and clinical significance. AJR Am J Roentgenol 2001;177:409–413.


Meniscal Lesions: Discoid Menisci


Discoid meniscus. Sagittal proton density-weighted images using
4-mm–thick sections demonstrate meniscus on four contiguous images (A–D). Coronal image (E) shows the meniscus extending into the joint (arrow) near the tibial spine.


Suggested Reading
Ryu KN, Kim IS, Kun EJ, et al. MR imaging of tears of discoid menisci. AJR Am J Roentgenol 1998;171:963–967.


Ligament and Tendon Injuries: Basic Concepts



FIGURE 5-29 Ligament and tendon anatomy of the knee seen from posterior (A), lateral (B), and axial (C) planes.
Suggested Reading
Berquist TH. MRI of the musculoskeletal system. 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2006:303–429.


Ligament and Tendon Injuries: Anterior Cruciate Ligament—Acute (Primary Features)


FIGURE 5-30 (A) Sagittal proton density-weighted image demonstrating the normal low-signal intensity of the ACL (arrows). (B) Acute ACL tear. Sagittal proton density-weighted image demonstrates an ACL tear (arrow). There is a joint effusion (open arrow) that is almost always present with an acute injury. Coronal fast spin-echo T2-weighted image (C) shows no visualized ACL (arrow), marrow edema in the lateral femoral condyle and tibia, and high-signal intensity along the MCL (arrow) caused by ligament sprain.
Suggested Reading
Barry KP, Mesgarzadeh M, Triolo J, et al. Accuracy of MRI patterns in evaluating anterior cruciate ligament tears. Skel Radiol 1996;25:365–370.
Tung GA, Davis LM, Wiggins ME, et al. Tears of the anterior cruciate ligament: Primary and secondary signs at MR imaging. Radiology 1993;188:661–667.


Ligament and Tendon Injuries: Anterior Cruciate Ligament—Acute (Secondary Features)


FIGURE 5-31 (A) Normal PCL with an angle (lines) of 140 degrees. Normal greater than 113 to 114 degrees. (B) ACL tear with hooked PCL (broken line). (C) ACL tear with hooked PCL and angle (lines) of less than 90 degrees.


FIGURE 5-32 Sagittal T2-weighted (A) and axial fat-suppressed fast spin-echo T2-weighted image (B) of a lateral compartment bone bruise (arrow) in a patient with an ACL tear.
Suggested Reading
TR, Moses M, Kier R, et al. MR diagnosis of tears of the anterior
cruciate ligament of the knee: Importance of ancillary findings. AJR Am J Roentgenol 1994;162:115–119.


Ligament and Tendon Injuries: Anterior Cruciate Ligament—Chronic Tears
FIGURE 5-33 Old partial ACL tear with intermediate signal intensity and horizontal distal remnant (arrow). There is no joint effusion.
Sagittal T1-weighted images with thickening and intermediate signal
intensity in the region of the ACL but no visible fibers. There is no
joint effusion, and the femur is shifted posteriorly on the tibia.


Suggested Reading
H, Winpfheimer O, Havamati N, et al. Diagnosis of partial tears of the
anterior cruciate ligament of the knee. Value of MR imaging. AJR Am J Roentgenol 1995;165:893–897.


Ligament and Tendon Injuries: Posterior Cruciate Ligament
FIGURE 5-35 Sagittal proton density-weighted image demonstrating a normal PCL.
FIGURE 5-36 PCL tear. Sagittal proton-density (A) and T2-weighted (B) images demonstrate thickening and increased signal intensity in the PCL with avulsion from the tibial attachment (arrow).


Suggested Reading
A, Disler DG, Short WB, et al. Internal derangements of the knee: Rates
of occurrence at MR imaging in patients referred to orthopedic surgeons
compared with rates in patients referred by physicians who are not
orthopedic surgeons. Radiology 1998;207:633–636.


Ligament and Tendon Injuries: Medial And Lateral Collateral Ligaments


FIGURE 5-37 (A) Coronal MR image of a normal low signal intensity MCL (arrows). T2 gradient-recalled echo images of a high-grade (B) and complete MCL tear (C). Note the wavy, lax appearance of the ligament (arrows) in (C).
Suggested Reading
Yao L, Dungan D, Seeger LC. MR Imaging of tibial collateral ligament injury. Comparison with clinical examination. Skel Radiol 1994;23:521–524.


Ligament and Tendon Injuries: Quadriceps Tendon
FIGURE 5-38 Coronal (A) and sagittal (B) fast spin-echo T2-weighted images with fat suppression demonstrate a complete quadriceps tear at the patellar attachment (arrows).
Suggested Reading
Yu JS, Petersilge C, Sartoris DJ, et al. MR imaging of injuries of the extensor mechanism. Radiographics 1994;14:541–551
HU, Bollmann C, Kreutz R, et al. Quantification of intact quadriceps
tendon, quadriceps tendon insertion and suprapatellar fat pad: MR
arthrography, anatomy, and cryosection in the sagittal plane. AJR Am J Roentgenol 1999;173:691–698.


Ligament and Tendon Injuries: Patellar Tendon
FIGURE 5-39 Sagittal proton density-weighted image of a normal patellar tendon.


FIGURE 5-40 Patellar tendon disorders. (A) Sagittal T2-weighted image shows thickening and increased signal intensity at the patellar attachment (arrow) resulting from “Jumper’s knee.” (B) Sagittal T1-weighted image demonstrating a complete tear of the tendon (arrow) with a wavy appearance distally.
Suggested Reading
Yu JS, Petersilge C, Sortores DJ, et al. MR imaging of injuries of the extensor mechanism. Radiographics 1994;14:541–551.


Ligament and Tendon Reconstruction


FIGURE 5-41 ACL repair with patellar tendon graft. (A) Patellar view showing bone donor site (arrow). (B) Notch view showing interference screws fixing the bone plugs. Graft tunnel positions (broken lines). (C) Lateral view demonstrating the tibial tunnel (broken lines) and tuberosity donor sight (arrow). (D) Cross-table lateral with extension showing the tibial tunnel (arrows) in proper position posterior to intercondylar roof (white line).


FIGURE 5-42 AP radiograph after ACL and MCL repairs. Staples fix the ends of the tendon grafts.


FIGURE 5-43 AP radiograph after ACL repair with fracture of the bone plug (arrow) and lucency about the screws (open arrow) caused by loosening.
FIGURE 5-44 Coronal (A) and sagittal (B) MR images of an intact tendon graft. Note normal low signal intensity of the tendon (arrows in B). There is some artifact from the screws.


FIGURE 5-45 Sagittal T2-weighted image demonstrating a large “cyclops” lesion (arrows) in the anterior fat.
FIGURE 5-46 Sagittal T1-weighted image after ACL repair showing displacement of the interference screw (arrow) into the joint.
Suggested Reading
RT, Hebl G, Mergo PJ, et al. Tunnel placement in anterior cruciate
ligament reconstruction: MR analysis as an important factor in the
radiological report. Skel Radiol 1997;26:409–413.
White LM, Kramer J, Recht MP. MR imaging evaluation of the postoperative knee: Ligaments, menisci, and articular cartilage. Skel Radiol 2005;34:431–452.


FIGURE 5-47 Plicae of the knee in the sagittal (A) and frontal plane with the knee flexed (B).


FIGURE 5-48 Sagittal (A) and axial (B) T2-weighted images of a complex, thickened suprapatellar plica (arrows).
Suggested Reading
Johnson DP, Eastwood DM, Witherow PJ. Symptomatic synovial plicae of the knee. J Bone Joint Surg 1993;75A:1485–1495.


Patellar Disorders: Patellofemoral Relationships
FIGURE 5-49 Wiberg patellar configurations. (A) Medial and lateral facets equal in size: Type I. (B) Lateral facet larger than medial: Type II. (C) Small medial facet with dysplastic condyle: Type III.



FIGURE 5-50 Normal radiographic relationships. (A) Sulcus angle formed by lines along the femoral condyles is normally 138 to 142 degrees. (B)
Lateral radiograph with the knee flexed 30 degrees. The patellar tendon
(PT) length over the patellar height (PH) = 1.02 ± 0.13. (C) The medial patellar edge should be at or just medial to a line (M) perpendicular to a line (C) along the condylar margins.
Suggested Reading
Laurin CA, Dussault R, Levesquelt P. The tangential x-ray investigation of the patellofemoral joint. Clin Orthop 1979;144:16–26.


Patellar Disorders: Patellar Tracking And Instability
FIGURE 5-51 Patellar views of both knees showing lateral tilt without subluxation because of lateral pressure syndrome.


FIGURE 5-52 Axial gradient echo image demonstrating lateral subluxation and a tear (arrow) of the medial retinaculum.
FIGURE 5-53 Sagittal (A) and axial (B)
T2-weighted MR images after patellar dislocation with fluid–fluid
levels, retinacular tear, and shaving of the patellar articular
cartilage (arrow).
Suggested Reading
Kirsh MD, Fitzgerald SW, Friedman H, et al. Transient lateral-patellar dislocation: Diagnosis with MR imaging. AJR Am J Roentgenol 1993;161:109–113.


Patellar Disorders: Chondromalacia Patella
Arthroscopic Classification MRI Classification and Image Features
Grade 1 Softening of cartilage Stage 1 Normal contour ± signal intensity changes
Grade 2 Blister-like swelling Stage 2 Focal areas of swelling with surface ↑ signal intensity
Grade 3 Surface irregularity and areas of thinning Stage 3 Irregularity with focal thinning and fluid extending into cartilage
Grade 4 Ulceration and bone exposed Stage 4 Areas of bone exposure
MRI, magnetic resonance imaging.


FIGURE 5-54 Normal articular cartilage (arrows) seen on T1- (A) and proton density fat-suppressed (B) images. (C) Fat-suppressed fast spin-echo image shows a full-thickness defect (Stage 4, arrow) and increased signal intensity and irregularity (open arrow) caused by chondromalacia.
Suggested Reading
Rose PM, Demlow TA, Szumowski J, et al. Chondromalacia patellae: Fat-suppressed MR imaging. Radiology 1994;193:437–440.


Loose Bodies


FIGURE 5-55 AP (A) and lateral (B) radiographs of an ossified loose body posteriorly (arrow). Note the normal fabella (open arrow), which should not be confused with a loose body. Coronal double-echo steady state (C) and fat-suppressed proton density axial (D) images demonstrate loose bodies (arrows) in a popliteal cyst.
Suggested Reading
J, Preidler KW, Daener B, et al. Imaging of osseous and cartilaginous
intra-articular bodies of the knee: Comparison with MR imaging, and MR
arthrography with CT and CT arthrography in cadavers. Radiology 1996;200:509–517.


Osteochondritis Dissecans
Histologic and MR Features
Grade Arthroscopic Features MR Features
Grade 0 Normal Normal
Grade 1 Focal softening, fissuring Cartilage intact, signal intensity abnormal in bone and cartilage
Grade 2 Defect in cartilage Breach in cartilage
Grade 3 Fragment partially detached Thin rim of abnormal signal intensity around fragment
Grade 4 Displaced fragment or loose in joint Mixed signal intensity with fragment loose or displaced
MR, magnetic resonance.


FIGURE 5-56 AP (A), lateral (B), and notch views (C) demonstrating characteristic appearance and location of osteochondritis dissecans (arrow). Note the lesion is most easily appreciated on the notch view.


MR features of osteochondritis dissecans. Grade 1 = abnormal signal
intensity, Grade 2 = linear defect in the cartilage, Grade 3 = abnormal
signal intensity (↑ T2, ↓ T1-weighted image) around the fragment, Grade
4 = fragment has abnormal signal intensity surrounding it, and it may
be loose.


FIGURE 5-58 MR images of osteochondritis dissecans in two different patients. T2-weighted sagittal (A) and axial (B) images showing a large defect with high-intensity fluid (arrows) separating the fragment from the condyle. This is an unstable lesion. (C) Sagittal T2-weighted image in a different patient showing abnormal signal intensity (arrows), no fluid line around the lesion, and intact cartilage. This is a stable lesion.
Suggested Reading
Aicroth P. Osteochondritis dissecans of the knee: A clinical survey. J Bone Joint Surg 1971;53B:440–447.
DeSmet AA, Ilahi O, Graf BK. Reassessment of MR criteria for osteochondritis dissecans of the knee and ankle. Skel Radiol 1996;25:159–163.


Spontaneous osteonecrosis. Notch view of the knee demonstrating
subchondral fracture and collapse of the medial femoral condyle.


FIGURE 5-60 Standing views of the knees demonstrating bilateral bone infarcts with dense ossification or calcification along the margins.


FIGURE 5-61 Coronal T1-weighted images of the knees with avascular necrosis in both femoral condyles and tibial and femoral bone infarcts.
Suggested Reading
Yamamoto T, Bullough PG. Spontaneous osteonecrosis of the knee: The result of subchondral insufficiency fracture. J Bone Joint Surg 2000;82A:858–869.




FIGURE 5-62 Blount disease. AP radiographs of both knees (A,B) showing metaphyseal and epiphyseal deformities medially with genu varum deformities of the knees.


FIGURE 5-63 Osgood-Schlatter disease. (A) Lateral radiograph demonstrates swelling and fragmentation (arrow) of the tibial tuberosity. (B)
Sagittal T2-weighted MR image in a different patient shows increased
signal intensity and fluid along the tendon at the level of the tibial
Suggested Reading
Craig JG, van Holsbeeck M, Zaltz I. The utility of MR in assessing Blount disease. Skel Radiol 2002;31:208–213.
Resnick D. Osteochondrosis. In: Resnick D, ed. Bone and joint imaging, 2nd ed. Philadelphia: WB Saunders; 1996:960–978.



Condition Radiographic Features
Osteoarthritis Primarily medial and patellofemoral involvement
Joint space narrowing, osteophytes, increased bone density
CPPD Joint space narrowing
Bone sclerosis
Rheumatoid arthritis Bilateral, symmetrical uniform joint space narrowing
Marginal erosions
Cystic changes
Psoriatic arthritis Bilateral asymmetric involvement
No osteopenia
Bone proliferation
Reiter syndrome Bilateral asymmetric
No osteopenia
Bone proliferation
Ankylosing spondylitis Knee involvement uncommon
Early erosions and bone sclerosis lead to ankylosis
Juvenile chronic arthritis Unilateral with tricompartmental involvement
Overgrowth of epiphysis and patella
Looks similar to hemophilia
Hemophilia Overgrowth of epiphysis and wide notch
Square patella
More cysts compared with juvenile chronic arthritis
Septic arthritis Unilateral
Aggressive weight-bearing cartilage loss
Pigmented villonodular synovitis Knee most common joint involved
Joint space narrows early
Cystic changes
Increased soft tissue density or masslike structures about the joint
CPPD, calcium pyrophosphate deposition disease.


FIGURE 5-64 Standing views of the knee showing medial compartment narrowing, more evident on the right, caused by osteoarthritis.


Calcium pyrophosphate deposition disease. Standing AP view of the knees
showing cartilage calcification and degenerative joint changes.


FIGURE 5-66 Rheumatoid arthritis. AP (A) and lateral (B) radiographs demonstrate a joint effusion (arrowheads) with slight joint space narrowing. There are no erosions.
FIGURE 5-67 Reiter syndrome. Standing AP (A) and lateral (B)
views of the knee demonstrating bilateral arthropathy with bone
proliferation or whiskering at the ligament and tendon attachments.


FIGURE 5-68 Hemophilic arthropathy. Standing (A) and lateral (B) views showing loss of joint space, wide notches, osteopenia, epiphyseal deformity, and squaring of the patella.


FIGURE 5-69 Pigmented villonodular synovitis. Sagittal proton density-weighted (A) and T2-weighted (B) images demonstrating extensive synovial proliferation with areas of low signal intensity caused by hemosiderin deposition.
Suggested Reading
Brower AC. Arthritis in black and white, 2nd ed. Philadelphia: WB Saunders; 1997.


Neoplasms: Bone Tumors And Tumorlike Conditions
Lesion Total/No. in Knee/% in Knee
Osteosarcoma 1649/795/48%
Fibrosarcoma 255/80/31%
Chondrosarcoma 895/143/16%
Ewing sarcoma 512/71/14%
Lymphoma 694/75/11%
Giant cell tumor 568/282/50%
Chondromyxoid fibroma 45/17/38%
Osteochondroma 872/325/37%
Chondroblastoma 119/44/37%
Aneurysmal bone cyst 289/68/24%
Chondroma 290/44/15%
Osteoid osteoma 331/41/12%


FIGURE 5-70 Osteoid osteoma. AP standing (A) and notch (B) views of the right knee showing a questionable tibial defect (arrow). (C) Radionuclide bone scan is positive (arrow) in this region. (D) CT image clearly defines the osteoid osteoma (arrow).


FIGURE 5-71 Osteosarcoma. (A)
Coronal T1-weighted image demonstrates low signal intensity tumor
involving the distal femur and extending into the epiphysis on the
right. (B) T2-weighted image in a different patient shows the extent of soft tissue involvement.


Suggested Reading
Kransdorf M, Berquist TH. Musculoskeletal neoplasms. In: Berquist TH, ed. MRI of the musculoskeletal system, 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2006:802–915.
Unni KK. Dahlin’s bone tumors: General aspects and data on 11,087 cases. Philadelphia: WB Saunders; 1996.


Neoplasms: Soft Tissue Tumors And Masses
FIGURE 5-72 Popliteal cyst. Fat-suppressed fast spin-echo proton density axial (A) and sagittal (B) images show a well-defined septated high signal intensity popliteal cyst.


FIGURE 5-73 Axial proton density (A) and T2-weighted (B) images of a septated ganglion cyst medially (arrow).
FIGURE 5-74 Sagittal proton density (A) and T2-weighted (B) images demonstrate an ACL ganglion (arrow).


FIGURE 5-75 Malignant fibrous histiocytoma. Axial proton density (A) and T2-weighted (B) images show an irregular, inhomogeneous mass anterior to the patella.
Suggested Reading
Kransdorf M, Berquist TH. Musculoskeletal neoplasms. In: Berquist TH, ed. MRI of the musculoskeletal system, 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2006:802–915.


Chronic Overuse/Miscellaneous Conditions: Bursitis
Prepatellar Between patella and skin
Retropatellar Between patellar tendon and tibia
Pretibial Between tibial tuberosity and skin
Suprapatellar* Between quadriceps and femur
Gastrocnemius Between lateral head of gastrocnemius and joint capsule
Fibular Between fibular collateral ligament and biceps tendon
Fibular popliteal Between fibular collateral ligament and popliteus tendon
Popliteal* Between popliteus tendon and lateral femoral condyle
Gastrocnemius* Between medial head of gastrocnemius and capsule
Pes anserine Between tibial collateral ligament and gracilis, sartorius, and semitendinosus tendons
Semimembranosus-tibial collateral ligament Between semimembranosus tendon and medial collateral ligament
*Communicates with the joint.


FIGURE 5-76 Bursae about the knee.


FIGURE 5-77 Pes anserine bursitis. Sagittal (A) and axial (B) T2-weighted images demonstrating high signal intensity (arrows) along the medial tendons.
Suggested Reading
Forbes JR, Nelius CA, Janzen DL. Acute pes anserine bursitis: MR imaging. Radiology 1995;194:525–527.


Chronic Overuse/Miscellaneous Conditions: Iliotibial Band Syndrome
FIGURE 5-78 Iliotibial band syndrome. (A) Normal coronal image of the iliotibial band (arrows). (B) Thickened band (arrowheads) and fluid collection (arrow) on a T2-weighted coronal MR image in a patient with iliotibial band syndrome.
Suggested Reading
Murphy BJ, Hechtman KS, Uribe JW, et al. Iliotibial band friction syndrome: MR image findings. Radiology 1992;185:569–571.


Chronic Overuse/Miscellaneous Conditions: Muscle Tears
FIGURE 5-79 Plantaris tear. Axial T2-weighted MR image showing fluid (arrows) between the soleus and gastrocnemius. The tendon of the plantaris is absent.


FIGURE 5-80 Popliteus muscle tear. (A) Sagittal T2-weighted image demonstrates increased signal intensity in the popliteus muscle (arrows). The PCL is hooked (arrowhead) because of an associated ACL tear. Note the joint effusion. (B)
Axial fat-suppressed fast spin-echo T2-weighted image shows abnormal
signal intensity involving greater than 50% of the muscle belly (Grade
2+ strain).


Suggested Reading
Brown TR, Quinn SF, Wensel JP, et al. Diagnoses of popliteus injuries with MR imaging. Skel Radiol 1995;24:511–514.

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