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Ultrasound of the Month Diagnosis Index

Case 96 Popliteal (Baker’s) Cyst and Ganglion Cyst of The Popliteal Fossa of the Knee

Two patients who were referred to the ultrasound department for ultrasound-guided aspiration of a cyst in the popliteal fossa of the knee.

Palpable mass or fullness in the back of the knee is a common clinical scenario for which the first line imaging modality is ultrasound. Ultrasound is a fast, accurate, and cost-effective modality for identifying the source of a mass in the back of the knee. Cysts, including Baker’s cysts and ganglion cysts, are commonly found, but less common sources of “masses”, including thrombosed veins, popliteal artery aneurysms, hematomas, and tenosynovitis, can be accurately diagnosed on ultrasound.

Baker’s cysts are an extension of the synovial compartment of the knee and are commonly seen in knees with chronic inflammation such as osteoarthritis. By definition, they communicate with the joint via a thin neck located between the semimembranosus and the medial head of the gastrocnemius.

The long term benefit of ultrasound-guided aspiration +/- cortisone injection for Baker’s cysts is controversial, although it is very safely performed and can be an effective treatment for symptomatic Baker’s cysts in the short term. Other cysts in the popliteal fossa that are not located in the characteristic location for Baker’s cysts are ganglion cysts and do not communicate with the knee joint. Ultrasound-guided aspiration +/- cortisone injection is a safe and effective treatment for ganglion cysts of the popliteal fossa, similar to ganglion cysts elsewhere in the body.

Case 95 Osteitis Pubis

A 43-year-old male presents with groin pain related to playing soccer.

Osteitis pubis is part of a spectrum of injuries that can result in groin pain or athletic pubalgia. Athletic pubalgia, the definition of which overlaps with "sports hernia," is common with sports that involve excessive twisting and shear-type stress at the pubic symphysis, such as soccer, ice hockey, and Australian-rules football. Osteitis pubis is thought to be a result of microinstability at the pubic symphysis, and subchondral irregularity and bone marrow edema are hallmarks on MRI.

Treatment for osteitis pubis and other sources of athletic pubalgia include rest and strengthening of the surrounding core muscles. Long-term role of cortisone injection is uncertain; however, it can provide therapeutic relief in patients who have not adequately recovered after other modes of therapy.

Although pubic symphyseal injection can be performed under fluoroscopy or even CT guidance, ultrasound guidance is fast, avoids radiation exposure, and is safe when done by experienced hands.

Case 94 Peripheral Nerve Sheath Tumor

A 67-year-old male presents with progressively worsening right knee pain in one pinpoint location.

Peripheral nerve sheath tumors (PNST) develop from nerve sheaths external to the central nervous system. PNSTs are predominantly benign; however, large tumors and those associated with neurofibromatosis 1 can demonstrate malignant transformation.

Benign PNSTs include schwannoma, neurofibroma (localized, diffuse cutaneous and plexiform), perineuroma and hybrid nerve sheath tumors. Patients typically present with a painful soft tissue mass and may demonstrate associated focal neurologic symptoms. On examination, a firm, non-compressible, painful lesion is appreciated.

Case 93 Avulsion fracture of the superior pole of the patella and partial rupture of the quadriceps tendon

51-year-old male with pain and weakness in extending the knee after acute sports injury.

Quadriceps injury can manifest as either a partial or complete rupture of the tendon or as an avulsion fracture of the superior pole of the patella, where the quadriceps inserts. Injury usually occurs due to rapid contraction of the muscle while the knee is flexed.

Ultrasound is a useful imaging modality for assessing these patients, and its quicker exam time, cost-effectiveness, and lack of contraindications are advantages of ultrasound compared to MRI. Ultrasound can assess the extent of tendon involvement (partial vs complete rupture) and for the presence of an avulsion fracture.

Case 92 Retained Metallic Foreign Body

63-year-old male with painful mass of the index finger.

Ultrasound is an ideal modality to evaluate soft tissue masses of the extremities. A retained foreign body can be a source of a palpable mass, and ultrasound can easily identify foreign bodies and differentiate them from other masses.

Most foreign bodies are bright on ultrasound regardless of the type of foreign body. A very bright and linear foreign body may be either metal or glass. An X-ray may be required to confirm the type of retained foreign body.

Ultrasound is also good for assessing any accompanying complications associated with the retained foreign body. Granulomatous reaction, abscess, tendon tear, and septic arthritis or tenosynovitis are potential complications of a retained foreign body.

Case 91 Complete tear of the left Achilles tendon

A 75-year-old male presents with bilateral, left greater than right, ankle pain and swelling for 1 week following the completion of a 10 day course of Levaquin for a diarrheal illness acquired in India.

Achilles tendon ruptures are typically related to sports trauma, rapid plantar flexion or forceful dorsiflexion of a plantar flexed foot. Patients frequently present with an audible pop with associated posterior ankle pain and swelling, weakened plantar flexion and more pronounced passive dorsiflexion.

Predisposing factors include middle aged “weekend warriors”, repeated microtrauma, diabetes mellitus, inflammatory conditions, intratendinous steroid injections, and fluoroquinolone antibiotic use. Ruptures commonly occur in the critical zone, a relatively hypovascular region approximately 4-6 cm proximal to the calcaneal insertion.

Case 90 Nerve sheath tumor of the tibial nerve

46-year-old female with tingling of all the toes.

Nerve sheath tumors are soft tissue neoplasms, typically benign, that are made up of variable degrees of Schwann cells, fibroblasts, and collagen. The two most common forms of nerve sheath tumors are neurofibromasand schwannomas, and they are histologically benign although they can demonstrate growth over time. Patients may present with a slowly growing palpable mass or with symptoms related to the involved nerve. If the involved nerve is in the extremity, ultrasound is an ideal modality for assessing these neoplasms.

On ultrasound, a nerve sheath tumor is identified as a hypoechoic mass arising within and enlarging a nerve, and containing internal vascularity. Distinguishing neurofibromasfrom schwannomas is not possible on ultrasound. On MRI, a nerve sheath tumor manifests as an enhancing solid mass within a nerve, and certain imaging features and enhancement patterns may suggest the particular type of nerve sheath tumor.

Case 89 Re-tear of previously repaired subscapularis tendon

70-year-old female with pain and poor range of motion 4 months after rotator cuff repair.

Ultrasound is an ideal modality for evaluating the rotator cuff tendons of the shoulder, with accuracy comparable to that of MRI according to many published reports. The integrity of each of the four rotator cuff tendons is confirmed if a robust tendon is seen attaching to the greater or lesser tuberosities of the humerus on ultrasound. In a full-thickness cuff tear, fluid is commonly seen replacing where a normal tendon is usually located.

In a shoulder with a previously repaired rotator cuff, suture anchor marking where the tendon was repaired is usually visible on ultrasound. If there are no tendinous fibers attached to the suture anchor (i.e. a bare suture anchor), this is indicative of a re-tear. Ultrasound is also the preferred modality under which an arthrocentesis is performed if there is concern that the rotator cuff re-tear is a result of an infection.

Case 88 Flexor digitorumsuperficialis tendon transection

A 55-year-old left-handed woman presents with a left index finger laceration sustained while pitting an avocado.

Penetrating injury to the palmar aspect of the finger most frequently results from knife wounds or broken glass. Open lesions may lead to injury of several flexor tendons and may be associated with concomitant vascular and/or nervous injury. Injury to the flexor digitorumsuperficialis(FDS) tendon is more common than injury to the flexor digitorumprofundus(FDP) tendon due to the more vulnerable superficial location of the FDS.

Flexor tendon injuries are categorized into five topographic zones:

  • Zone I: From the distal insertion of the FDP on the distal phalanx to the distal insertion of the FDS on the middle phalanx
  • Zone II: From the distal insertion of the FDS to the A1 pulley
  • Zone III: From the A1 pulley to the distal aspect of the carpal tunnel
  • Zone IV: Comprised of the flexor tendons within the carpal tunnel
  • Zone V: From the proximal aspect of the carpal tunnel to the flexor tendon musculotendinous junction

Lacerations usually affect the mid-substance of the tendon as opposed to its insertion site. Zone II lacerations occur most frequently and are associated with a high rate of adhesions, as well as tendon entrapment or triggering. Zone III, IV and V lacerations tend to also involve the adjacent neurovascular structures and lumbricalmuscles. Sonographic findings indicative of flexor tendon injury include focal disruption of the fibrillartendon, unsynchronized movement of the torn proximal and distal tendon stumps with dynamic maneuvers, as well as associated tenosynovialeffusion. Dynamic ultrasound can help increase the conspicuity of a complete tendon tear, determine the size of the tendon gap and indicate the amount of tendon retraction.

Ultrasound may also be utilized to detect concomitant interdigital nerve injury, which may be evidenced by focal nerve interruption acutely or hypoechoic fusiform thickening/neuroma formation in the more subacute-chronic phase of injury. Early diagnosis of tendon injury is crucial, as sonographic evaluation, as well as tendon repair, become more challenging following the development of adhesions and fibrosis, which may occur within one to two weeks of the injury. Complete lacerations necessitate surgical intervention, while partial tendon tears can be treated conservatively.

Case 87 Plantar Fasciitis with tear

74-year-old female with heel pain for several months.

Formerly believed to be a chronic inflammatory condition, plantar fasciitis is now considered a degenerative process involving the plantar fascial origin at the medial tubercle of the calcaneus. Risk factors for plantar fasciitis with or without tears include anatomic factors such as pes planus, pes cavus, excessive femoral anteversion, and increased body weight, as well as certain activities, particularly running. Patients present with long-standing heel pain with or without more acute symptoms if there is a superimposed fascial tear.

In terms of imaging, both MRI and ultrasound can identify fasciitis as an area of thickening and increased signal (MRI) or diminished echogenicity (Ultrasound), usually involving the medial fibers at the calcaneal origin. A tear would manifest as an abnormal linear cleft usually at the calcaneal origin or immediately distal to the calcaneus. Treatment includes NSAIDS, orthotics, stretching exercises and percutaneous procedures such as injection of cortisone or platelet-rich plasma (PRP). If conservative treatment fails, surgical fasciotomy is also a treatment option.

Case 86 Gout

56-year-old male with known osteoarthritis of the metatarsophalangeal (MTP) joint of the great toe presented with acute pain and swelling over the medial side of the great toe.

Gout is a crystal deposition disease in which tophi made up of monosodium urate form in soft tissues, including within joints, and incite an inflammatory arthritis. Elevation of serum uric acid is suggestive, but a definitive diagnosis requires the identification of negatively birefringent monosodium urate crystals in the affected site.

Ultrasound is a cost-effective imaging modality for assessing a joint that could potentially be affected by an inflammatory arthritis. Ultrasound also has the advantage of allowing guided arthrocentesis.

Case 85 No left lower extremity deep venous thrombosis. Thrombosed popliteal artery aneurysm.

A 71-year-old male presents with fullness in the left popliteal fossa and some pain with walking.

Aneurysmal dilatation of the popliteal artery is defined as an arterial diameter > 1.5 x the normal popliteal artery diameter, which ranges from 0.7-1.1 cm. Most popliteal artery aneurysms (PAAs) are categorized as true aneurysms, as they are comprised of all three blood vessel wall layers, the intima, media and adventitia. True PAAs are the most prevalent peripheral artery aneurysm. Risk factors associated with PAAs include advanced age, male gender, atherosclerosis, hypertension, and smoking. An increased incidence of concomitant aneurysms is seen with PAAs, and it is thus imperative to screen for coexisting abdominal aortic and contralateral PAAs.

Many patients with PAAs are asymptomatic; however, symptoms related to PAAs include lower extremity claudication, rest pain or ischemia, which may result from thrombosis or distal embolization. Ultrasound is the imaging modality of choice to diagnose PAAs and can assess for aneurysm patency and thrombus burden. Early diagnosis of PAAs is essential, as they have the potential to result in thrombosis, distal embolization and may even rupture. PAAs > 2 cm, even when asymptomatic, as well as those < 2 cm with substantial associated thrombus are typically repaired either via an endovascular or open approach, due to the high incidence of associated complications.

Case 84 Congenital patellar dislocation

7-month-old boy with congenital flexion contracture of the left knee. Clinical concern was for congenital patellar dislocation.

Congenital patellar dislocation is a rare condition in which the infant or toddler may present with a flexion contracture of the knee, genu valgum, or delayed walking. Although it may occur in isolation, there is an increased incidence of syndromic associations, including Larson syndrome, nail-patella syndrome, Down syndrome, and Ellis-van Creveld syndrome. Because the patella does not begin to ossify until 3-4 years of age, congenital patellar dislocation cannot be confidently diagnosed on radiographs. MRI and CT scan can diagnose this entity, although the former is expensive and may require sedation, while the latter involves ionizing radiation.

Ultrasound can identify both ossified bones as well as bones that are not yet ossified, making it a quick and accurate exam for evaluating many osseous structures in infants. Identifying the position of the unossified patella with respect to the femoral trochlea can easily diagnose or exclude patellar dislocation. Dynamic maneuvers performed concurrently can assess whether the patellar dislocation, if present, is fixed or reducible. Treatment of congenital patellar dislocation is surgical, as there is a high risk of permanent deformity and early osteoarthritis if left untreated.

Case 83 Rotator cuff calcific tendonitis

51-year-old female with shoulder pain and limited range of motion for one year.

Calcium hydroxyapatite deposition into a tendon, “calcific tendonitis”, most commonly occurs in the rotator cuff of the shoulder. Calcific tendonitis progresses through various phases; within the calcific stage, the formative phase is followed by the resting phase and then the resorptive phase. The resorptive phase is the most painful phase. Diagnosis can be made using either x-ray, MRI, or ultrasound.

Ultrasound has the advantage of allowing for a guided barbotage and cortisone injection during the same visit. Barbotage can break up the calcium and may speed up the resorption of the calcium hydroxyapatite deposit. Cortisone is injected into the subacromial-subdeltoid bursa to address the bursitis. If ultrasound-guided barbotage fails to provide pain relief, surgical debridement and repair of the affected rotator cuff may be indicated.

Case 82 Flexor pollicis longus (FPL) tendon rupture superimposed on moderate to severe FPL tendinosis

62-year-old male status post right distal radius open reduction and internal fixation in 2011 presents with the inability to flex his right thumb at the interphalangeal joint after doing heavy housework two weeks prior.

Flexor tendon rupture is a relatively infrequent, yet significant complication following distal radius fracture open reduction and volar plate fixation. Patients present with worsening pain, crepitus and/or decreased finger active range of motion. Most flexor tendon ruptures take place approximately 6 months to two years following surgery.

Flexor tendon ruptures resulting from volar plating occur twice as frequently in women and 1/3 of the time present between the ages of 60 and 70; however, this may be related to the increased incidence of distal radius fractures occurring in this population as a result of osteoporosis.

Factors contributing to attrition of the flexor tendon include distal plate placement, prominence of the distal edge of the plate, protruding screw heads, insufficient coverage of the distal plate edge by the pronator quadratus, fracture site collapse, tendinopathy (i.e. steroid use) as well as tendon injury.

Treatment of flexor tendon rupture consists of hardware removal and flexor tendon repair. Possible interventions to prevent flexor tendon injury following distal radius volar plating include proper plate selection and placement, precise surgical technique, repair of the pronator quadratus muscle, and/or early hardware removal.

Case 81 Haglund syndrome

45-year-old female with progressive heel pain without history of antecedent trauma.

Haglund syndrome is a constellation of soft tissue abnormalities associated with an osseous prominence of the calcaneal tuberosity. The osseous prominence is referred to as a Haglund deformity or “pump bump”, because it is commonly associated with women’s pumps.

Soft tissue abnormalities that make up Haglund syndrome consist of insertional Achilles tendinosis, retrocalcaneal bursitis, and retroAchilles bursitis. These can be identified on either MRI or ultrasound. Ultrasound has the advantage of allowing for a guided cortisone injection during the same visit.

Cortisone injection into the retrocalcaneal bursa can be performed safely under ultrasound. Because the Haglund bump is believed to be contributory, the cortisone injection may only provide short-term relief and these patients may be candidates for surgical resection of the osseous protuberance of the calcaneal tuberosity.

Case 80 Iliopsoas Tendinosis due to impingement by acetabular cup after hip replacement

64-year-old male with progressive anterior hip pain 1 year after hip replacement.

The iliopsoas tendon is susceptible to irritation after ipsilateral hip replacement. Typical history is groin pain upon walking up and down stairs and getting out of a car. Iliopsoas tendinosis with or without iliopsoas bursal distension may be seen on ultrasound.

The advantage of ultrasound is that direct impingement of the iliopsoas tendon by the acetabular cup may be visible; on MRI, susceptibility artifact from the metal can make evaluation of this area challenging.

Ultrasound-guided injection of anesthetic and cortisone can be performed for diagnostic and therapeutic purposes. Under ultrasound, the needle can be placed safely adjacent to the iliopsoas tendon and iliopsoas bursal injection can be easily performed.

Case 79 Right Rib Osteochondroma

3 year-old-girl with a painless lump at the anterior right chest.

Osteochondroma is the most common benign tumor of bone. Common sites of involvement are the long bones in the lower and upper extremity, favoring the metaphysis. Much less commonly, they can be seen in the hands and feet, the pelvis, and the scapula. Spine and rib involvement is rare.

The hallmark of this lesion on imaging is cortical and medullary continuity with the parent bone. The overlying hyaline cartilage cap is well visualized and accurately measured using US, appearing hypoechoic (dark). Osteochondromas are usually asymptomatic, presenting as a painless, hard and slow-growing lump. After skeletal maturity, these lesions cease to grow.

Although uncommon, complications related to this lesion are largely due to mass effect on adjacent structures, e.g. nerve or vascular impingement, bursal formation. The risk of malignant transformation of solitary osteochondroma is approximately 1%. A thickened cartilage cap > 2 cm is strongly suspicious for malignancy.

Case 78 Distal biceps rupture with tendon retraction

30-year-old male with acute right elbow pain and weakness flexing the elbow during weight lifting. Clinical concern was for a distal biceps tear. Ultrasound evaluation of the biceps was requested.

Discussion: Biceps rupture is an uncommon injury, usually occurring at its insertion on the radial tuberosity of the proximal radius. Patients present with weakness of elbow flexion and forearm supination after hearing a pop in the elbow. Significant proximal retraction of the tendon stump implies an injury to the biceps aponeurosis.

Diagnosis is usually made clinically, and MRI can confirm the diagnosis. Ultrasound, a quicker and more tolerated exam than MRI, can also identify biceps ruptures and assess the degree of tendon retraction. Surgery is recommended in most cases of distal biceps ruptures.

Case 77 Painful Os trigonum

25-year-old female with intermittent posterior ankle pain. MRI showed the presence of an os trigonum, but without bone marrow edema. Ultrasound-guided anesthetic injection of the os trigonum was requested to assess whether it was a symptom generator.

Discussion: Os trigonum is a fragment of bone of the lateral tubercle of the posterior process of the talus that has failed to fuse with the remainder of the talus. The incidence is said to be 7% of the population. Although it may be an incidental finding, it can be the source of pain in individuals who do activities requiring repetitive plantarflexion of the ankle, such as ballet dancers or soccer players. A painful os trigonum is often called "os trigonum syndrome", and it is one of a few conditions that can result in posterior ankle impingement.

Radiological studies play a pivotal role in evaluating patients with clinical symptoms of posterior ankle impingement.

MRI can identify an os trigonum as well as the extent of soft tissue involvement such as synovial scarring and FHL tenosynovitis. On MRI, bone marrow edema (high signal intensity on inversion recovery sequences) in the os trigonum and posterior process of talus are suggestive of a symptomatic os trigonum, but it is not 100% sensitive.

Ultrasound can also identify an os trigonum, but more importantly, it can be used to guide needle placement for a targeted injection of anesthetic with or without cortisone. If the patient feels symptomatic relief after injection of anesthetic around the os, it can increase the diagnostic confidence of the foot and ankle specialist that the os trigonum is the symptom generator.

Case 76 Flexor carpi radialis tenosynovitis

76-year-old woman with right wrist pain and palpable mass at the volar radial wrist. The patient was referred for a wrist ultrasound to assess for a ganglion cyst.

Discussion: The flexor carpi radialis (FCR) tendon has a complex insertion at the wrist, with the majority of the tendon (80%) inserting at the base of the 2nd metacarpal. 20% of the tendon insert on the 3rd metacarpal, and a few tendon slips attach to the trapezium.
The FCR tendon is encased in a sheath from the musculotendinous junction to the trapezium, and it is outside the carpal tunnel. When the tendon sheath is distended with fluid, this is called tenosynovitis.

FCR tenosynovitis is generally associated with two main conditions:

  • Overuse: Manual labor, golf or racquet sports
  • Arthritis: Radiocarpal or basilar joint arthritis

Post-traumatic FCR tenosynovitis can also be seen after a scaphoid or distal radius fracture.

Treatment is usually non-operative and includes immobilization, non-steroidal anti-inflammatory medication (NSAIDs) and peritendinous corticosteroid injection. Ultrasound guidance is ideal for safe and accurate FCR peritendinous corticosteroid injection.

Case 75 Biceps long head tenosynovitis with loose body in the tendon sheath

68-year-old female with progressively worsening left anterior shoulder pain.

Discussion: The biceps tendon long head is a common source of anterior shoulder pain.Usually due to repetitive overuse, the biceps tendon can undergo various pathologies, including tendinosis, tenosynovitis, split tears, dislocations, and ruptures. All of these conditions can be accurately assessed on ultrasound. Cortisone injection into the biceps tendon sheath is a percutaneous treatment option for anterior shoulder pain due to the biceps tendon long head.Under ultrasound guidance, the position of the needle with respect to the target can be visualized in real time so that tendon sheath injection can be performed accurately and puncturing adjacent structures such as vessels, the subscapularis tendon, or the biceps tendon long head itself can be avoided.Ultrasound also allows the radiologist to identify and address unexpected findings, such as soft tissue masses and fluid collections.

Case 74 Parameniscal cyst of the knee

22-year-old female with progressive lateral knee pain after prior ACL reconstruction and lateral meniscal repair. MRI showed a large multilobulated lateral parameniscal cyst.

Discussion: Parameniscal cyst is a ganglion cyst arising from the meniscus due to a chronic tear of the meniscus. Fluid leaks out from the meniscal tear into the extraarticular soft tissues and becomes confined by a pseudocapsule. As the cyst slowly enlarges, it can become symptomatic as it causes mass effect on surrounding soft tissues. Definitive treatment for parameniscal cysts is to surgically treat the underlying meniscal tear. A non-invasive percutaneous treatment option is aspiration and fenestration under ultrasound guidance. Performing the procedure under ultrasound allows the radiologist to directly visualize the cyst, needle, and relevant soft tissues including the popliteal artery in the current case. Cortisone is often injected at the end of the procedure, although the extra benefit of cortisone in preventing recurrence of parameniscal as well as ganglion cysts in general is controversial.

Case 73 Chronic left superior peroneal retinaculum rupture and anterior subluxation of the peroneus brevis tendon

38-year-old man with chronic left posterior lateral ankle pain and snapping sensation.

Discussion: The superior peroneal retinaculum (SPR) extends from the lateral periosteum of the lateral malleolus and attaches posteriorly on the Achilles and/or calcaneus.A normal SPR acts to keep the peroneal tendons in place within the peroneal groove at the posterior aspect of the lateral malleolus.A chronically torn SPR can result in recurrent peroneal tendon subluxation or dislocation, presenting as painful lateral ankle snapping or popping usually when walking up or down stairs.Ultrasound can efficiently evaluate for peroneal tendon subluxation or dislocation using real-time and dynamic imaging.Conservative management involves cast immobilization. If symptoms persist, surgical repair is highly successful.

Case 72 Lipoma of the antecubital fossa of the elbow

50-year-old female with slowly-growing palpable mass along the antecubital fossa of the elbow. An ultrasound was requested to rule out a soft tissue mass.

Discussion: Soft tissue lipomas are benign tumors composed of mature adipocytes that usually present as an incidental soft palpable mass.Although they are benign, they may require imaging to confirm that it is a lipoma and not an aggressive neoplasm.MRI is the most accurate modality for characterizing fat-containing tumors that are located in the deep soft tissues.For superficial lesions, ultrasound is also an accurate modality for confirming that a palpable mass is indeed a lipoma. Compared to MRI, ultrasound is more cost effective, faster, and better tolerated by patients.

Case 71 Stenosing FHL tenosynovitis

26-year-old female ballet dancer with left posterior ankle pain and difficulty dancing en pointe.

Discussion: The FHL tendon, because of its function to plantarflex the great toe and because of its particular course along the posterior ankle, is susceptible to irritation particularly in ballet dancers. Chronic irritation of the tendon can result in both tendinosis and tenosynovitis of the FHL posterior to the ankle. Like all tendons in the foot and ankle, because the FHL courses relatively superficially in the soft tissues, it is a structure that is optimally evaluated by ultrasound. Stenosing tenosynovitis, in which hypertrophic scarring of the tendon sheath can have a constricting effect on the tendon, can result in pain and diminished excursion of the FHL.

Case 70 Partial thickness laceration injury of the palmaris longus tendon

35-year-old woman with laceration injury to the volar wrist and paresthesias with palpation of the laceration.

Discussion: The palmaris longus is variably absent in between 5%-27% of the patient population. When present, the palmaris longus tendon can be found as a long and flat tendon at the volar wrist, coursing over then inserting on the central flexor retinaculum. Its superficial location makes it particularly susceptible to laceration injury. The palmaris longus tendon is a common source of tendon graft given its length and lack of functional deficit with harvest. Given its close proximity to the median nerve, injury or irritation to the palmaris longus tendon may cause paresthesias and the median nerve should be closely evaluated for concomitant injury. When harvesting the palmaris longus tendon, nerve stimulation is performed to confirm the median nerve is left intact.

Case 69 Quadriceps tendon rupture

53-year-old male with hyperflexion injury to the knee 6 days prior.

Discussion: Quadriceps tendon rupture usually occurs during rapid contraction of the muscle while the knee is flexed. Ultrasound is a useful imaging modality for diagnosing acute quadriceps ruptures, and its quicker exam time, cost-effectiveness, and lack of contraindications are advantages of ultrasound compared to MRI.
In the acute phase, fluid associated with the injury will outline the torn tendon and increase the conspicuity of the tear. In the chronic phase, the tear is often harder to detect due to the presence of scar tissue that may appear similar to tendon.

Case 68 Muscle herniation of the anterior tibialis muscle

35-year-old male with painful swelling over the anterior shin during exercise, noticed several months prior.

Discussion: Focal herniation of muscle through a defect of the fascia can be symptomatic, causing either a palpable lump beneath the skin or vague compartment-syndrome-like pain. Onset of symptoms upon exercise is classic. Ultrasound allows direct visualization of the herniating muscle, which can usually be elicited upon active muscle contraction by the patient. Because of this dynamic component to the evaluation, ultrasound is the best modality for diagnosing this entity; MRI, because it is a static exam, may not be able to identify the herniating muscle.

Case 67 Anconeus epitrochlearis muscle (accessory anconeus muscle)

42-year-old woman with numbness in the left fourth and fifth fingers. The patient was referred for an ultrasound (US) of the elbow to assess for ulnar nerve pathology.

Discussion: The anconeus epitrochlearis is an accessory muscle which originates from the olecranon and inserts on the medial epicondyle.This accessory muscle at the elbow may be asymptomatic but has been implicated as a cause of cubital tunnel syndrome which leads to ulnar neuritis. The anconeus epitrochlearis may be unilateral or bilateral. The anconeus epitrochlearis, also known as the accessory anconeus, is not to be confused with the anconeus muscle which is found at the lateral aspect of the elbow.

Case 66 Pedunculated osteochondroma of the distal femur

14-year-old girl with history of hard palpable mass along the anterior thigh, which was first noticed several months prior.

Discussion: Osteochondromas are benign cartilaginous tumors that manifest as bony excrescences with a cartilage cap, most commonly occurring around the knee. Treatment is usually conservative, although surgical resection may be considered in symptomatic patients, as in our patient. Intraoperative radiographs show the osteochondroma in our patient before (a) and after (b) surgical excision.

Case 65 Complete laceration of the flexor digitorum profundus and superficialis tendons with a tendinous gap

39-year-old female with inability to flex either the proximal or distal interphalangeal joints of the left pinky after finger laceration with a glass.

Discussion: Penetrating injuries such as accidental lacerations from a glass or knife are relatively common in the wrists and hands, and the laceration can cause a tendon tear if deep enough. The superficial location of these tendons and relative thinness of the overlying soft tissues make ultrasound a quick and ideal modality for assessing the integrity of these tendons.

Case 64 A4 pulley rupture of the right ring finger

30-year-old woman with pain in the right middle and ring fingers following rock-climbing injury. The patient was referred for an ultrasound (US) to assess for tendon injury.

Discussion: There are 5 pulleys associated with the flexor tendon sheath of the finger. The most important for biomechanical function are the A2 and A4 pulleys. The A2 is the strongest pulley but most commonly injured. Pulley rupture is an overuse injury commonly seen in rock-climbers. Sonography is effective in the evaluation of pulley rupture and can be useful to assess for the integrity of the flexor tendon.

Case 63 SPN stump neuroma due to latrogenic nerve transection

39-year-old man with history of prior ORIF of tibial fracture and multiple subsequent surgeries including fasciotomy.

Discussion: One of the complications of a nerve transection, either post-traumatic (eg. due to penetrating injury) or deliberate (as part of limb amputation) is the development of a stump neuroma. Stump neuroma can result in pain and parasthesia in the distribution of that nerve. Ultrasound can be a very accurate modality for evaluating the integrity of nerves, particularly nerves that course superficially in the extremities.

On ultrasound, a stump neuroma manifests as a heterogenous soft tissue/scar at the end of a transected nerve. As in this case, ultrasound-guided injection of anesthetic around the nerve and the scar can be helpful for confirming that the patient's symptoms are related to the stump neuroma.

Case 62 Impingement of the FHL tendon

Impingement of the FHL tendon by the proud tip of distal tibial screw causing irritation and tenosynovitis of the tendon.

Discussion: MRI and ultrasound play complementary roles in assessing for complications after surgery. Because of the outstanding soft tissue contrast and overall spatial resolution, an MRI is usually a good first line test in detecting complications such as infection, synovitis, and tenosynovitis. Ultrasound is valuable for evaluating soft tissues, and when evaluating the positioning of hardware in relation to anatomic structures, ultrasound is not susceptible to metal artifact to the same degree that MRI is. In addition, dynamic maneuvers on ultrasound may reveal information such as tendon subluxation or soft tissue herniation that static exams such as MRI will not detect.

Case 61  Right hip joint synovitis

Discussion:
Hip joint synovitis is a common cause of hip pain and limping in the pediatric population.

Radiographic evaluation usually shows no abnormality.

Sonography is useful to determine the presence or absence of a joint effusion.

The benefits of sonography include the ability to evaluate the contralateral side and the lack of ionizing radiation, particularly advantageous in the pediatric population.

Case 60 Glomus tumor

Discussion:
45-year old female with pain in the fingertip of the middle finger.

The patient did not want an MRI due to claustrophobia, thus an ultrasound was requested.

Case 59 Gamekeeper's thumb

Discussion:
Gamekeeper's thumb (or skier's thumb) describes a UCL avulsion fracture or rupture, usually off the base of the first proximal phalanx.

These injuries at the ulnar aspect of the 1st MCP joint may lead to significant instability, at times requiring surgical intervention.

As the structures about the 1st MCP joint are superficial, ultrasound is a useful and efficient modality to assess for the integrity of ligamentous structures following trauma to the thumb.

Case 58 Plantar fibromatosis.

Plantar fibromatosis, also known as Ledderhose disease, is the development of fibrous nodules, often multiple, in the plantar fascia. It can co-exist with palmar fibromatosis (Dupuytren’s contracture).

Case 57 Arterial pseudoaneurysm after knee replacement.

Pseudoaneurysm is an uncommon complication after total knee arthroplasty, with a reported incidence of 0.03% to 0.2%.
Symptoms of a pseudoaneurysm include pain, gait disability, cold foot, pulsatile mass and recurrent hemarthrosis.
Ultrasound is a cheap, sensitive modality for patients suspected of a pseudoaneurysm.
If a pseudoaneurysm is detected by ultrasound, MRA may be indicated to more accurately delineate the parent artery for possible embolization.

Case 56 Common peroneal nerve scar encasement.

Trauma is the most common cause of acquired peripheral neuropathy, occurring as either direct injury to the nerve (e.g. laceration, contusion) or indirect injury (e.g. scar encasement, entrapment).

Peripheral nerves have a characteristic appearance on US which helps in their identification.

Scar tissue usually appears as hypoechoic/dark tissue on US, and can cause encasement or entrapment of adjacent nerves.

US is useful in the evaluation of peripheral nerves, particularly when there is adjacent metallic hardware that can limit MRI evaluation.

Case 55 Diagnosis: Birth-related clavicle fracture

The clavicle is the most common site of birth-related fracture, reported to occur in up to 1% of vaginal deliveries.
Risk factors for fracture of the clavicle include large size of the baby, forceps delivery, and shoulder dystocia.
Although easily diagnosed by radiographs, ultrasound is an ideal alternative as it is fast, accessible, and most importantly, lacks ionizing radiation.
Additional value of ultrasound is that it can evaluate the soft tissues surrounding the clavicle should the patient’s palpable abnormality be caused by an entity other than a clavicle fracture.

Case 54 Diagnosis: DeQuervain’s tenosynovitis

Painful inflammation of the abductor pollicis longus and extensor pollicis brevis tendons. Most common in women and often in the 30-50 year age group Tendon tears are relatively uncommon. Associated with repetitive activities such as racquet sports, golf, manual labor and frequently lifting and holding a newborn child (as in the case presented). May also be associated with conditions such as rheumatoid arthritis. Treatment options include NSAIDs, physical therapy, reduction in the activities causing pain, and cortisone injections. Cortisone injections should be done with ultrasound guidance to confirm accuracy. Severe cases without response to more conservative measures may require surgery.

Case 53 Diagnosis: Peri-patellar bursitis:

Discussion:
Involves inflammation of the synovial-lined bursa between the skin and the patella or the patellar tendon. Common condition, often related to repetitive kneeling (carpenters, maids, gardeners, etc.) Also associated with gout, rheumatoid arthritis, diabetes, uremia, etc. With any clinical suspicion for infection, ultrasound-guided aspiration should be performed.

Case 52 Diagnosis: Metatarsal stress fracture:

Discussion:
Radiographs remain the initial diagnostic study of choice in evaluating for a metatarsal fracture. If radiographs are normal but the diagnosis is still suspected, MRI is the gold standard. In patients who cannot have an MRI and in other selected circumstances, an ultrasound of the area may confirm the presence of a fracture. However, if the ultrasound imaging is normal, fracture cannot be excluded and further imaging and follow-up is necessary.

Case 51 Primary synovial chondromatosis

Discussion:
The core biopsy samples obtained demonstrated findings compatible with primary synovial chondromatosis. This is a relatively rare condition with proliferation of islands of irregularly hypercellular cartilage seen microscopically.

Most commonly seen in the knee, this process may arise from joint synovium or less likely a tendon sheath. The condition is twice as common in men and in the primary form has no known precipitating factors.

Case 50 Bicipitoradial Bursitis

Discussion:
Bicipitoradial bursitis is a relatively uncommon condition resulting in inflammation and distention of the bicipitoradial bursa. This enlarged bursa may impinge upon the adjacent radial nerve bifurcation and posterior interosseous nerve.

Bicipitoradial bursitis is most commonly secondary to repetitive activity and may be associated with biceps tendon tears or tendinosis. In rare cases, the bursa may be infected and require antibiotic therapy and possible surgical intervention.

As demonstrated in this case, ultrasound is valuable in evaluating the distal biceps tendon for tear/tendinosis and in confirming the presence of an enlarged and inflamed bursa. Also, ultrasound allows safe needle aspiration and injection of the bursa as indicated.

Case 49 Intramuscular lipoma of the vastus lateralis muscle

Discussion:
Microscopic pathologic review of the core specimens obtained demonstrated Adipose tissue containing small bands of bland fibrous tissue and numerous skeletal muscle fibers. No evidence of mineralization.

Case 48 Plantar foot abscess following puncture injury

Discussion:
Costal cartilage fractures may be a difficult clinical diagnosis.

Gram stain with culture and sensitivity of the fluid obtained from aspiration yielded gram-positive cocci (Staph Aureus).

Case 47 Costochondral junction fracture

Discussion:
Costal cartilage fractures may be a difficult clinical diagnosis.

Radiographs are generally normal in the absence of an associated rib fracture.

While, as demonstrated, the diagnosis may be made by either CT or ultrasound imaging (as well as MRI), ultrasound is less expensive, faster, and like MRI avoids the use of radiation.

Case 46 Ganglion cyst

Discussion:
Ganglion cyst extending from the tibial tunnel into the adjacent soft tissues in the setting of prior ACL reconstruction.

MRI is the examination of choice in evaluating the integrity of the ACL in the setting of prior reconstruction and easily demonstrates the presence of ganglion cysts

Ultrasound may be used to confirm the diagnosis and more importantly to guide the safe and complete aspiration of these ganglion cysts

Ganglion cyst fluid is often extremely thick, requiring the use of larger (16-18 gauge) needles for complete aspiration

As clinically indicated, the fluid may be sent for laboratory analysis to exclude the possibility of infection.

Case 45 Complete tear of the ulnar collateral ligament with avulsion

Complete tear of the ulnar collateral ligament of the thumb with avulsion

Discussion:
While MRI has historically been the imaging study of choice for evaluating the ulnar collateral ligament, ultrasound will often quickly make the diagnosis and should be considered when this diagnosis is suspected.

It is important that complete tears are detected early so that prompt surgical correction may be performed.

Case 44 Temporal (giant cell) arteritis

Case 43 Full-thickness tear of the anchilles tendon

Case 42 Lateral ankle sprain

Case 41 Patellar tendon rupture

The interval elevation of the patella and increased patella-tibial tubercle distance as consistant with patellar tendon rupture.

Case 40 Giant cell tumor of tendon sheath

Giant Cell Tumor of Tendon Sheath involving the extensor tendon of the 2nd digit of the hand, also referred to as localized nodular tenosynovitis. Pathologically, the tissue is identical to PVNS. Lesions contain histiocyte-like multinucleated cells and fibroblastic cells. Frequently, they contain hemosiderin deposits.

Case 39 Calcium hydroxyapatite deposition disease

Case 38 Sciatic nerve stump neuroma

Case 37 Foreign Bodies

Case 36 Paralabral cyst

Paralabral cyst extending posteriorly and impinging the sciatic nerve.

Case 35 Post-traumatic seroma

Post-traumatic seroma interposed between the medial gastrocnemius and soleus muscles following partial medial gastrocnemius tear. Ultrasound-guided seroma aspiration may allow prompt resolution of symptoms and rapid improvement in patient mobility. The use of ultrasound during these procedures allows safe and accurate needle placement and ensures complete evacuation of the fluid collection.

Case 34 Ganglion cyst

Immediately following aspiration of the ganglion cyst, the patient was able to painlessly perform the ballet maneuvers and great toe flexion that had previously elicited discomfort. As clinically indicated, cortisone injection into the ganglion could also be performed at the time of the initial cyst aspiration. Due to the relatively high recurrence rate of ganglion cysts, the patient will be monitored clinically for evidence of symptom recurrence.

Case 33 Osgood-Schlatter disease

Case 32 Mucin-secreting adenocarcinoma

Moderately differentiated mucin-secreting adenocarcinoma, consistent with a pulmonary origin. This matched the previous pathology of the patient's primary lung tumor.

Case 31 Peripheral nerve sheath tumor

Peripheral nerve sheath tumor of the ulnar nerve.

Case 30 Congenital muscular torticollis

Congenital Muscular Torticollis.

Case 29 Meralgia paresthetica

Based on the clinical presentation, the diagnosis of meralgia paresthetica was considered most likely. Ultrasound evaluation of the lateral femoral cutaneous nerve was requested with peri-neural anesthetic injection to confirm the diagnosis.

Case 28 Calcific tendinosis

Calcific tendinosis of the proximal hamstring tendons.

Case 27 Infected olecranon bursitis

Case 26 Tarsal tunnel syndrome secondary to tibial nerve compression

Tarsal tunnel syndrome secondary to tibial nerve compression from a perineural ganglion cyst.

Treatment of choice is ultrasound-guided aspiration of the cyst with resulting nerve decompression.

Case 25 Ganglion cyst

Ganglion Cyst.

Case 24 Spinoglenoid notch cyst

Spinoglenoid notch cyst causing denervation atrophy and fatty replacement of the infraspinatus muscle.

Case 23 Partial thickness tear of the proximal patellar tendon

Partial thickness tear of the proximal patellar tendon.

Case 22 Nodular Pigmented Villonodular Synovitis

Nodular Pigmented Villonodular Synovitis arising from the lateral tibiotalar joint.

Case 21 Myxomatous tumors of the soft tissues

Myxomatous tumors of the soft tissues are a heterogeneous group of lesions, both benign and malignant, that show an overproduction of mucopolysaccharide substances. Characterized by a mixture of primitive mesenchymal cells and myxomatous stroma.

Case 20 Paralabral cyst compressing the femoral nerve

Following the ultrasound-guided aspiration of the paralabral cyst compressing the femoral nerve, the patient experienced symptomatic relief of her femoral nerve symptoms.

Case 19 Calcific tendinosis

Calcific tendinosis of the long head of the rectus femoris tendon at the Anterior Inferior Iliac Spine

Case 18 Schwannoma

Case 17 Epidermoid inclusion cyst

Case 16 Giant cell tumor with ABC formation

Case 15 Sindig-Larson-Johansson syndrome

Case 14 Right rectus abdominus hypertrophy

Right rectus abdominus hypertrophy with strain common in tennis players.

Case 13 Traumatic peroneus brevis tear

Traumatic peroneus brevis tear status post ultrasound guided PRP injection with healing response.

Case 12 Glomus tumor of the terminal tuft

Case 11 Lateral epicondylitis with deep surface tear of extensor tendon

Lateral epicondylitis with deep surface tear of extensor tendon origin/lateral collateral ligament with seroma formation. Ultrasound guided seroma aspiration and platlet rich plasma injection.

Case 10 Early osteoarthritis with lateral hip impingement

Case 9 Scar encasement/neuroma formation about ulnar nerve

Case 8 Lateral femoral cutaneous nerve entrapment

Initial imaging shows hypoechoic scarring surrounding the nerve near the Iliac crest and Sartorius origin. Ultrasound guided perineural injection was Performed resulting in symptomatic relief.

Case 7 Linear calcification in anterior joint capsule

Linear calcification in anterior joint capsule producing anterior impingement and pain.

Case 6 Large foreign body granuloma

Large foreign body granuloma containing multiple foreign bodies.

Case 5 De Quervain’s tendinitis/tenosynovitis

Large tendon sheath effusion, inhomogeneity of the first dorsal compartment tendons with marked hyperemia on power Doppler imaging.

Case 4 Isolated teres minor atrophy

Isolated teres minor atrophy:

  • Atrophic muscle appears echogenic and and diminutive in size
  • Normal muscle is hypoechoic on ultrasound
  • Teres minor atrophy often due to injury of the axillary nerve as it passes through the quadrilateral space

Case 3 Peroneal tenosynovitis

Ultrasound shows fluid and nodular soft tissue surrounding the peroneal tendons giving rise to the soft tissue swelling seen on radiographs.

Case 2 Osteomylitis

Case 1 Gout

Sonographic appearances suggestive of gout. Confirmed on ultrasound guided aspiration.

 

 

Ultrasound of the Month Cases