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Radiology quiz
QUIZ
Radiology quiz Questions
Case 2 A 72-year-old man presented with a left wrist injury following a fall. Wrist radiographs (Figure 2a and b) were taken. What is the diagnosis? What are the complications if missed and left untreated.
Case 1 A 19-year-old presented with chronically worsening lower back pain. History, examination and biochemistry revealed no systemic features. Concerned by ongoing symptoms an MRI was performed (Figure 1). What is the diagnosis?
Figure 1 Sagittal STIR from an MRI performed on a 19-year-old for chronically worsening lower back pain. Figure 2 (a) Frontal wrist radiograph of a 72-year-old male with wrist injury. (b) Lateral wrist radiograph of a 72-year-old male with wrist injury.
Omar Azmat MBBS Specialist Registrar Radiology, Department of Musculoskeletal Radiology, Leeds Teaching Hospital, Leeds, UK. Imran Kasli MBChB Specialist Registrar Radiology, Department of Musculoskeletal Radiology, Leeds Teaching Hospital, Leeds, UK. James Rankine MD FRCR MRCP Consultant Musculoskeletal Radiologist, Department of Musculoskeletal Radiology, Leeds Teaching Hospital, Leeds, UK.
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Case 3 A young female presented after a lorry had accidentally driven over her foot. She had intense pain and found it difficult to weight bear. Foot radiographs were taken (Figure 3). Given the history what diagnosis is of most concern and what do the radiographs show?
Case 4 A 2-year-old boy presented with repeated falls and mild tenderness of the right pelvis. On examination there was no swelling or erythema. Inflammatory markers and other laboratory parameters were unremarkable. A pelvic radiograph was taken (Figure 4). What are the findings and differential diagnoses?
Figure 4 Frontal pelvic radiograph of a two-year-old boy with repeated falls and tenderness of the right pelvis. Figure 3 AP and oblique radiographs of the foot for a young female who suffered a crush injury.
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Case 5 An adolescent male presented with anterior elbow pain aggravated by activity. Clinical examination revealed tenderness on movement. An elbow radiograph was taken (Figure 5). What is the diagnosis? What are the potential complications?
Case 6 A teenager presented with foot pain on increasing activity. Examination revealed a flat foot with limited inversion and tenderness over the mid foot. Foot radiographs were taken (Figure 6). What is the diagnosis and how should this be investigated further?
Figure 6 Oblique foot radiograph of a teenager with limited inversion and tenderness of the mid foot.
Figure 5 Frontal elbow radiograph of an adolescent male with pain aggravated on activity.
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Answers
The evolution of spondylolysis has been described in 4 stages.4,5 The first stage (grade 1) consists of a stress reaction only visible on bone scintigraphy and MRI. The second stage (grade 2) constitutes early pars defect and includes hairline fractures and bone resorption evident on CT as well as MRI. The third stage (grade 3) is a complete pars fracture with or without fragmentationdalso referred to as progressive spondylolysis. The fourth stage (grade 4), referred to as terminal spondylolysis, is characterized by nonunion of the fracture and sclerotic fracture margins, which may demonstrate poor radionuclide activity on bone scintigraphy and low signal on MRI. In chronic, untreated conditions there may be progression to spondylolisthesis (lytic spondylolisthesis). Timely diagnosis and effective management can lead to good outcomes and healing.
Case 1 MRI is the initial investigation of choice in individuals under 50 with ‘alert signs’ of back pain.1 The differential includes congenital, infective and malignant aetiologies. Given the unremarkable physical and biochemical markers a stress fracture of the pars inter-articularis is most likely. Lumbar spine radiographs were normal. MRI revealed high T2 signal within the right-sided pars inter-articularis and pedicle at L5 however no fracture (Figure 7a and b). Subsequent MR examination revealed a fracture across the previously oedematous pars inter-articularis (Figure 8), consistent with a pars defect. Further conservative management prevented progression with a satisfactory healing response on MRI.
Figure 7 (a) 19-year-old diagnosed with a developing pars defect. Sagittal STIR sequences of the lumbar spine with high signal at the right-sided pedicle (broken arrow) and pars inter-articularis (solid arrow). (b) 19-year-old diagnosed with a developing pars defect. Sagittal T1 sequence of the lumbar spine with low signal at the right-sided pars inter-articularis however no fracture (solid arrow).
Case 2 The AP wrist radiograph shows increased scapholunate distance, known as the Terry Thomas or Madonna sign. This corresponds to an increased scapholunate angle seen on the lateral projection consistent with a dorsal intercalated segmental instability of the wrist (DISI deformity), which predisposes the wrist to major degeneration. The scapholunate ligament is an intrinsic interosseous ligament contributing to stabilization of the wrist joint. It maintains the proximal scaphoid pole adjacent to the lunate and stabilizes the palmar rotational force of the scaphoid against the dorsal rotational force of the lunate. Plain radiography in two views is fairly sensitive for significant injury with dynamic, loaded or traction films further increasing sensitivity. A tear is best confirmed with MRI (Figure 9a and b), ideally with MR arthrography. 3 T MRI scanners enable reliable evaluation in the absence of intra-articular contrast however small tears may be difficult to diagnose.6,7
Figure 8 19-year-old diagnosed with a pars defect. Sagittal T1 sequence of the lumbar spine with a fracture of the pars inter-articularis (solid arrow).
Pars defect is a disruption of the pars inter-articularis of the neural arch. A large prospective study of spondylolysis reported a prevalence of 4.4% in children and 6% in the general population.2 This is traumatic but coronally orientated facets predispose.3
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Figure 9 (a) 72-year-old male diagnosed with a scapholunate ligament injury. Coronal T2 weighted MRI of the wrist confirm an increased scapholunate distance and a discontinuous scapholunate ligament (solid arrow). (b) 72-year-old male diagnosed with a scapholunate ligament injury. Sagittal T2 weighted MRI of the wrist confirms a dorsal intercalated segmental instability (DISI) with dorsal subluxation of the lunate.
If significant tears with associated DISI deformities (scapholunate angles of over 60 degrees) are left untreated this may lead to severe radioscaphoid and lunocapitate degeneration progressing to SLAC (scapholunate advanced collapse) wrist with loss of carpal height by proximal migration of the capitate between the scapholunate gap. This progression leads to symptom progression with loss of up to 45% of wrist movement. Early diagnosis and ligament repair is vital to avoid significant morbidity and disability. Case 3 On the AP radiograph there is mal alignment of the medial edge of the 2nd metatarsal with the medial aspect of the middle cuneiform and an increase in distance between the 1st and 2nd metatarsals. These findings are consistent with significant ligamentous injury and disruption along the Lisfranc joint. CT (Figure 10) confirmed diagnosis.
Figure 10 Young female diagnosed with disruption across the Lisfranc joint. Coronal reformatted CT show a fracture at the base of the 2nd metatarsal and increase in distance between the 1st and 2nd metatarsal space. Further intra-articular comminuted fracture of the lateral cuneiform.
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
In young children with such clinical presentations a differential diagnosis of Langerhans Cell Histiocytosis (LCH), malignancy and osteomyelitis should be considered. Features here are more in keeping with an LCH due to normal inflammatory markers and a bone lesion that on radiological grounds is not as aggressive as expected for a neoplasm. Commonly histology is required for an end diagnosis. Langerhans Cell Histiocytosis is a proliferative disorder of Langerhan’s cells and has three types. Eosinophilic Granuloma is the most common and least aggressive. This may be accompanied by fever, leucocytosis and an eosinophilia making it hard to differentiate from an osteomyelitis. HandeSchullereChristian Disease is multiple bone and soft tissue involvement with the classical triad of calvarial bone defects, exophthalmos and diabetes insipidus. The third and most aggressive form is LetterereSiwe Disease that is acutely progressive with multiple organ involvement often leading to death. The incidence of LCH in tumours where a bone biopsy has been performed is less than 1%.12 This commonly occurs in males within the first two decades of life, where the most common skeletal manifestation is in the temporal bone of the skull. Around a third of solitary bone lesions involve the long bones; the femur being the most commonly involved.13
The tarsometatarsal articulation, also called the Lisfranc joint, is a bone and ligament complex that provides stability to a relatively rigid mid-foot.8 The Lisfranc ligament is a strong stabilizing ligament extending between the lateral aspect of the medial cuneiform and the plantar surface of the 2nd metatarsal base. It maintains stability and holds the second metatarsal base firmly at the apex of the transverse arch e the keystone of the arch. It is also the sole connection of the lesser metatarsals (IIeV) to the first ray because proximal inter-metatarsal ligaments exist between the lesser metatarsals but not between the first and second metatarsals. Lisfranc sprains in the athlete typically occur by indirect low-velocity longitudinally directed axial force on a foot plantar flexed and slightly rotated.9 Other mechanisms of injury to the Lisfranc joint include forced forefoot abduction, crush injury and non-specific twisting or falling injuries. Nunley et al10 have described three stages of injury, depending upon the extent of ligament injury and loss of stability. Stage 1 represents a Lisfranc ligament sprain with increased uptake on bone scan or signal change on MRI but no diastasis on weight bearing or loss of plantar arch. Stage 2 encompasses a 1e5 mm diastasis of the first and second metatarsal however no loss of plantar arch. Stage 3 represents significant instability with diastasis and a loss of the transverse plantar arch. Isolated Lisfranc ligament tear rarely occur and they are mostly associated with fractures.11 Significant displacement because of instability requires open repair and therefore accurate and timely diagnosis is vital. Case 4 The frontal pelvic radiograph shows a large lucent lesion within the right iliac bone with a sclerotic lateral edge however no periosteal reaction. Concerning appearances lead to an MRI for further characterization and revealed (Figure 11a and b) a large heterogeneous but predominantly high T2 signal mass arising from the iliac bone with a substantial soft tissue component. This was confirmed to be eosinophilic granuloma on open surgical biopsy.
Figure 11 (a) A two-year-old boy diagnosed with Eosinophilic Granuloma of the right iliac bone. T1 axial MRI shows a bulky, predominantly iso-intense mass arising from the right iliac bone with a large soft tissue component. (b) A two-year-old boy diagnosed with Eosinophilic Granuloma of the right iliac bone. T2 axial MRI shows a bulky high signal mass arising from the right iliac bone with a large soft tissue component and associated surrounding oedema.
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Case 5 The AP radiograph of the elbow demonstrates a well-defined lucency within the capitellum. On MRI (Figure 12a and b) this corresponds to an abnormal lesion with surrounding bone oedema. A rim of high T2 signal is demonstrated at the base of the lesion. This was diagnosed as an unstable osteochondral lesion and required surgical repair.
respectively. High signal at the base implies a cartilaginous defect with synovial fluid penetration. An unstable lesion usually warrants surgical repair14 however if diagnosed early, treatment may be conservative hence the importance of prompt diagnosis, suitable imaging and lesion categorization.
Figure 12 (a) An adolescent male diagnosed with an osteochondral lesion of the capitellum. T1 weighted coronal MRI of the elbow joint shows a focal loss of normal marrow signal in the capitellum (solid arrow). (b) An adolescent male diagnosed with an osteochondral lesion of the capitellum. T2 weighted coronal MRI of the elbow joint shows a high signal rim deep to an unstable capitellum bone fragment.
Case 6 The oblique foot radiograph reveals a calcaneonavicular coalition clinically causing peroneal spasm and limiting inversion of the foot with point tenderness elicited on examination.17 Tarsal coalition is an abnormal union between two bones of the hind and mid foot with cartilaginous, bony or fibrous connections. Involvement is commonly of the calcaneonavicular joint however the subtalar joints can also be involved.18 On plain films secondary signs include an elongated dorsal calcaneus (ant-eater sign) or a hypoplastic talus.19,20 Further imaging is with CT or MRI (Figure 13a and b). On CT bony coalitions reveal a bony bar between the coalesced bone surfaces while non-osseous coalitions will show a loss of joint space with reactive cystic and hypertrophic changes of the underlying bone.21 Similarly on MRI, an osseous coalition will reveal bony continuity. Fibrous and cartilaginous connections are of low and high T2 signal intensities respectively.
Osteochondritis dissecans is a pathological process affecting the articular cartilage and sub-chondral bone with an osteochondral defect in a focal area of bone that undergoes necrosis. As the bone is resorbed the overlying cartilage loses its supporting structure and the underlying bone fragment is displaced into the joint space.14 Proposed causes include micro trauma, ischaemia and genetics.15 It commonly occurs in the knee, however may occur at the elbow or ankle joint. Within the elbow it most commonly involves the capitellum. Plain films may be suggestive however an MRI is required for better delineation and assessment of lesion stability.16 There are four stages of Osteochondritis dissecans on MRI.14 Stage 1 is stable with flattening of the sub-chondral bone and thickening of the overlying articular cartilage. Stage 2 involves a breach of the articular cartilage with low signal change at the base of the lesion due to a stable fibrous connection. Stage 3 and 4 are unstable with high signal change at the base of the fragment and a loose body,
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Figure 13 (a) A teenager diagnosed with tarsal coalition. Sagittal CT reformat shows a non-osseous calcaneonavicular coalition with reduced joint space however no bone bridging. (b) A teenager diagnosed with tarsal coalition. Coronal T2 weighted MRI shows reduced calcaneonavicular joint space with low signal fibrous coalition (solid arrow). 10 Nunley JA, Vertullo CJ. Classification, investigation, and management of midfoot sprains: Lisfranc injuries in the athlete. Am J Sports Med 2002 NoveDec; 30: 871e78. PMID: 12435655. 11 Treatment Lisfranc’s sprain and minimally displaced fractures. Wheeless’ textbook of orthopaedics. http://www.wheeless online.com/ortho/treatment_lisfrancs_sprain_and_minimally_ displaced_frx. 12 David R, Oria RA, Kumar R, et al. Radiologic features of eosinophilic granuloma of bone. AJR Am J Roentgenol 1989 Nov; 153: 1021e26. PMID: 2801420. 13 Stull MA, Kransdorf MJ, Devaney KO. Langerhans cell histiocytosis of bone. Radiographics 1992 Jul; 12: 801e23. PMID: 1636041. 14 Hixon AL, Gibbs LM. Osteochondritis dissecans: a diagnosis not to miss. Am Fam Physician 2000 Jan 1; 61: 151e6, 158. PMID: 10643956. 15 Schenck RC Jr., Goodnight JM. Osteochondritis dissecans. J Bone Joint Surg Am 1996; 78: 439e56. PMID: 8613454. 16 Herman Kan J. Osteochondral abnormalities: pitfalls, injuries, and osteochondritis dissecans. Department of Diagnostic Imaging, Monroe Carell Jr Children’s Hospital at Vanderbilt. 17 Harris RI, Beath T. Etiology of peroneal spastic flat foot. J Bone Joint Surg Br 1948 Nov; 30B: 624e34. PMID: 18894612. 18 Varner KE, Michelson JD. Tarsal coalition in adults. Foot Ankle Int 2000 Aug; 21: 669e72. PMID: 10966365. 19 Oestreich AE, Mize WA, Crawford AH, Morgan RC Jr.. The “anteater nose”: a direct sign of calcaneonavicular coalition on the lateral radiograph. J Pediatr Orthop 1987 NoveDec; 7: 709e11. PMID: 3429658. 20 Sartoris DJ, Resnick DL. Tarsal coalition. Arthritis Rheum 1985 Mar; 28: 331e38. PMID: 31566043. 21 Wechsler RJ, Schweitzer ME, Deely DM, Horn BD, Pizzutillo PD. Tarsal coalition: depiction and characterization with CT and MR imaging. Radiology 1994 Nov; 193: 447e52. PMID: 7972761. 22 Wheelees’ textbook of orthopaedics e calcaneonavicular coalition. http://www.wheelessonline.com/ortho/calcaneonavicular_ coalition.
Initially conservative management is employed. In refractory cases an osseous coalescing bar is amenable to surgical resection. In the presence of degenerative changes across the talar joints an arthrodesis is considered.22 REFERENCES 1 Jarvik JG, Deyo RA. Diagnostic evaluation of low back pain with emphasis on imaging. Ann Intern Med 2002 Oct 1; 137: 586e97. PMID: 12353946. 2 Beutler WJ, Fredrickson BE, Murtland A, Sweeney CA, Grant WD, Baker D. The natural history of spondylolysis and spondylolisthesis: 45-year follow-up evaluation. Spine (Phila Pa 1976) 2003 May 15; 28: 1027e35; discussion 1035. PMID: 12768144. 3 Rankine JJ, Dickson RA. Unilateral spondylolysis and the presence of facet joint tropism. Spine (Phila Pa 1976) 2010 Oct 1; 35: E1111e4. http://dx.doi.org/10.1097/BRS.0b013e3181de8b72. PMID: 20838273. 4 Ralston S, Weir M. Suspecting lumbar spondylolysis in adolescent low back pain. Clin Pediatr (Phila) 1998 May; 37: 287e93. PMID: 9597294. 5 Saifuddin A, Burnett SJ. The value of lumbar spine MRI in the assessment of the pars interarticularis. Clin Radiol 1997 Sep; 52: 666e71. PMID: 9313730. 6 Shahabpour M, De Maeseneer M, Pouders C, et al. MR imaging of normal extrinsic wrist ligaments using thin slices with clinical and surgical correlation. Eur J Radiol 2011; 77: 196e201. PMID: 20599335 7 Davis KW, Blankenbaker DG. Imaging the ligaments and tendons of the wrist. Semin Roentgenol 2010; 45:194e217. PMID: 20483115. 8 Meyer SA, Callaghan JJ, Albright JP, Crowley ET, Powell JW. Midfoot sprains in collegiate football players. Am J Sports Med 1994 MayeJun; 22: 392e401. PMID: 7913587. 9 Curtis MJ, Myerson M, Szura B. Tarsometatarsal joint injuries in the athlete. Am J Sports Med 1993 JuleAug; 21: 497e502. PMID: 8368407.
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Ó 2013 Elsevier Ltd. All rights reserved.
Radiology quiz Questions
Case 2 A 72-year-old man presented with a left wrist injury following a fall. Wrist radiographs (Figure 2a and b) were taken. What is the diagnosis? What are the complications if missed and left untreated.
Case 1 A 19-year-old presented with chronically worsening lower back pain. History, examination and biochemistry revealed no systemic features. Concerned by ongoing symptoms an MRI was performed (Figure 1). What is the diagnosis?
Figure 1 Sagittal STIR from an MRI performed on a 19-year-old for chronically worsening lower back pain. Figure 2 (a) Frontal wrist radiograph of a 72-year-old male with wrist injury. (b) Lateral wrist radiograph of a 72-year-old male with wrist injury.
Omar Azmat MBBS Specialist Registrar Radiology, Department of Musculoskeletal Radiology, Leeds Teaching Hospital, Leeds, UK. Imran Kasli MBChB Specialist Registrar Radiology, Department of Musculoskeletal Radiology, Leeds Teaching Hospital, Leeds, UK. James Rankine MD FRCR MRCP Consultant Musculoskeletal Radiologist, Department of Musculoskeletal Radiology, Leeds Teaching Hospital, Leeds, UK.
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Case 3 A young female presented after a lorry had accidentally driven over her foot. She had intense pain and found it difficult to weight bear. Foot radiographs were taken (Figure 3). Given the history what diagnosis is of most concern and what do the radiographs show?
Case 4 A 2-year-old boy presented with repeated falls and mild tenderness of the right pelvis. On examination there was no swelling or erythema. Inflammatory markers and other laboratory parameters were unremarkable. A pelvic radiograph was taken (Figure 4). What are the findings and differential diagnoses?
Figure 4 Frontal pelvic radiograph of a two-year-old boy with repeated falls and tenderness of the right pelvis. Figure 3 AP and oblique radiographs of the foot for a young female who suffered a crush injury.
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Case 5 An adolescent male presented with anterior elbow pain aggravated by activity. Clinical examination revealed tenderness on movement. An elbow radiograph was taken (Figure 5). What is the diagnosis? What are the potential complications?
Case 6 A teenager presented with foot pain on increasing activity. Examination revealed a flat foot with limited inversion and tenderness over the mid foot. Foot radiographs were taken (Figure 6). What is the diagnosis and how should this be investigated further?
Figure 6 Oblique foot radiograph of a teenager with limited inversion and tenderness of the mid foot.
Figure 5 Frontal elbow radiograph of an adolescent male with pain aggravated on activity.
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Answers
The evolution of spondylolysis has been described in 4 stages.4,5 The first stage (grade 1) consists of a stress reaction only visible on bone scintigraphy and MRI. The second stage (grade 2) constitutes early pars defect and includes hairline fractures and bone resorption evident on CT as well as MRI. The third stage (grade 3) is a complete pars fracture with or without fragmentationdalso referred to as progressive spondylolysis. The fourth stage (grade 4), referred to as terminal spondylolysis, is characterized by nonunion of the fracture and sclerotic fracture margins, which may demonstrate poor radionuclide activity on bone scintigraphy and low signal on MRI. In chronic, untreated conditions there may be progression to spondylolisthesis (lytic spondylolisthesis). Timely diagnosis and effective management can lead to good outcomes and healing.
Case 1 MRI is the initial investigation of choice in individuals under 50 with ‘alert signs’ of back pain.1 The differential includes congenital, infective and malignant aetiologies. Given the unremarkable physical and biochemical markers a stress fracture of the pars inter-articularis is most likely. Lumbar spine radiographs were normal. MRI revealed high T2 signal within the right-sided pars inter-articularis and pedicle at L5 however no fracture (Figure 7a and b). Subsequent MR examination revealed a fracture across the previously oedematous pars inter-articularis (Figure 8), consistent with a pars defect. Further conservative management prevented progression with a satisfactory healing response on MRI.
Figure 7 (a) 19-year-old diagnosed with a developing pars defect. Sagittal STIR sequences of the lumbar spine with high signal at the right-sided pedicle (broken arrow) and pars inter-articularis (solid arrow). (b) 19-year-old diagnosed with a developing pars defect. Sagittal T1 sequence of the lumbar spine with low signal at the right-sided pars inter-articularis however no fracture (solid arrow).
Case 2 The AP wrist radiograph shows increased scapholunate distance, known as the Terry Thomas or Madonna sign. This corresponds to an increased scapholunate angle seen on the lateral projection consistent with a dorsal intercalated segmental instability of the wrist (DISI deformity), which predisposes the wrist to major degeneration. The scapholunate ligament is an intrinsic interosseous ligament contributing to stabilization of the wrist joint. It maintains the proximal scaphoid pole adjacent to the lunate and stabilizes the palmar rotational force of the scaphoid against the dorsal rotational force of the lunate. Plain radiography in two views is fairly sensitive for significant injury with dynamic, loaded or traction films further increasing sensitivity. A tear is best confirmed with MRI (Figure 9a and b), ideally with MR arthrography. 3 T MRI scanners enable reliable evaluation in the absence of intra-articular contrast however small tears may be difficult to diagnose.6,7
Figure 8 19-year-old diagnosed with a pars defect. Sagittal T1 sequence of the lumbar spine with a fracture of the pars inter-articularis (solid arrow).
Pars defect is a disruption of the pars inter-articularis of the neural arch. A large prospective study of spondylolysis reported a prevalence of 4.4% in children and 6% in the general population.2 This is traumatic but coronally orientated facets predispose.3
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Figure 9 (a) 72-year-old male diagnosed with a scapholunate ligament injury. Coronal T2 weighted MRI of the wrist confirm an increased scapholunate distance and a discontinuous scapholunate ligament (solid arrow). (b) 72-year-old male diagnosed with a scapholunate ligament injury. Sagittal T2 weighted MRI of the wrist confirms a dorsal intercalated segmental instability (DISI) with dorsal subluxation of the lunate.
If significant tears with associated DISI deformities (scapholunate angles of over 60 degrees) are left untreated this may lead to severe radioscaphoid and lunocapitate degeneration progressing to SLAC (scapholunate advanced collapse) wrist with loss of carpal height by proximal migration of the capitate between the scapholunate gap. This progression leads to symptom progression with loss of up to 45% of wrist movement. Early diagnosis and ligament repair is vital to avoid significant morbidity and disability. Case 3 On the AP radiograph there is mal alignment of the medial edge of the 2nd metatarsal with the medial aspect of the middle cuneiform and an increase in distance between the 1st and 2nd metatarsals. These findings are consistent with significant ligamentous injury and disruption along the Lisfranc joint. CT (Figure 10) confirmed diagnosis.
Figure 10 Young female diagnosed with disruption across the Lisfranc joint. Coronal reformatted CT show a fracture at the base of the 2nd metatarsal and increase in distance between the 1st and 2nd metatarsal space. Further intra-articular comminuted fracture of the lateral cuneiform.
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
In young children with such clinical presentations a differential diagnosis of Langerhans Cell Histiocytosis (LCH), malignancy and osteomyelitis should be considered. Features here are more in keeping with an LCH due to normal inflammatory markers and a bone lesion that on radiological grounds is not as aggressive as expected for a neoplasm. Commonly histology is required for an end diagnosis. Langerhans Cell Histiocytosis is a proliferative disorder of Langerhan’s cells and has three types. Eosinophilic Granuloma is the most common and least aggressive. This may be accompanied by fever, leucocytosis and an eosinophilia making it hard to differentiate from an osteomyelitis. HandeSchullereChristian Disease is multiple bone and soft tissue involvement with the classical triad of calvarial bone defects, exophthalmos and diabetes insipidus. The third and most aggressive form is LetterereSiwe Disease that is acutely progressive with multiple organ involvement often leading to death. The incidence of LCH in tumours where a bone biopsy has been performed is less than 1%.12 This commonly occurs in males within the first two decades of life, where the most common skeletal manifestation is in the temporal bone of the skull. Around a third of solitary bone lesions involve the long bones; the femur being the most commonly involved.13
The tarsometatarsal articulation, also called the Lisfranc joint, is a bone and ligament complex that provides stability to a relatively rigid mid-foot.8 The Lisfranc ligament is a strong stabilizing ligament extending between the lateral aspect of the medial cuneiform and the plantar surface of the 2nd metatarsal base. It maintains stability and holds the second metatarsal base firmly at the apex of the transverse arch e the keystone of the arch. It is also the sole connection of the lesser metatarsals (IIeV) to the first ray because proximal inter-metatarsal ligaments exist between the lesser metatarsals but not between the first and second metatarsals. Lisfranc sprains in the athlete typically occur by indirect low-velocity longitudinally directed axial force on a foot plantar flexed and slightly rotated.9 Other mechanisms of injury to the Lisfranc joint include forced forefoot abduction, crush injury and non-specific twisting or falling injuries. Nunley et al10 have described three stages of injury, depending upon the extent of ligament injury and loss of stability. Stage 1 represents a Lisfranc ligament sprain with increased uptake on bone scan or signal change on MRI but no diastasis on weight bearing or loss of plantar arch. Stage 2 encompasses a 1e5 mm diastasis of the first and second metatarsal however no loss of plantar arch. Stage 3 represents significant instability with diastasis and a loss of the transverse plantar arch. Isolated Lisfranc ligament tear rarely occur and they are mostly associated with fractures.11 Significant displacement because of instability requires open repair and therefore accurate and timely diagnosis is vital. Case 4 The frontal pelvic radiograph shows a large lucent lesion within the right iliac bone with a sclerotic lateral edge however no periosteal reaction. Concerning appearances lead to an MRI for further characterization and revealed (Figure 11a and b) a large heterogeneous but predominantly high T2 signal mass arising from the iliac bone with a substantial soft tissue component. This was confirmed to be eosinophilic granuloma on open surgical biopsy.
Figure 11 (a) A two-year-old boy diagnosed with Eosinophilic Granuloma of the right iliac bone. T1 axial MRI shows a bulky, predominantly iso-intense mass arising from the right iliac bone with a large soft tissue component. (b) A two-year-old boy diagnosed with Eosinophilic Granuloma of the right iliac bone. T2 axial MRI shows a bulky high signal mass arising from the right iliac bone with a large soft tissue component and associated surrounding oedema.
ORTHOPAEDICS AND TRAUMA 27:6
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Ó 2013 Elsevier Ltd. All rights reserved.
QUIZ
Case 5 The AP radiograph of the elbow demonstrates a well-defined lucency within the capitellum. On MRI (Figure 12a and b) this corresponds to an abnormal lesion with surrounding bone oedema. A rim of high T2 signal is demonstrated at the base of the lesion. This was diagnosed as an unstable osteochondral lesion and required surgical repair.
respectively. High signal at the base implies a cartilaginous defect with synovial fluid penetration. An unstable lesion usually warrants surgical repair14 however if diagnosed early, treatment may be conservative hence the importance of prompt diagnosis, suitable imaging and lesion categorization.
Figure 12 (a) An adolescent male diagnosed with an osteochondral lesion of the capitellum. T1 weighted coronal MRI of the elbow joint shows a focal loss of normal marrow signal in the capitellum (solid arrow). (b) An adolescent male diagnosed with an osteochondral lesion of the capitellum. T2 weighted coronal MRI of the elbow joint shows a high signal rim deep to an unstable capitellum bone fragment.
Case 6 The oblique foot radiograph reveals a calcaneonavicular coalition clinically causing peroneal spasm and limiting inversion of the foot with point tenderness elicited on examination.17 Tarsal coalition is an abnormal union between two bones of the hind and mid foot with cartilaginous, bony or fibrous connections. Involvement is commonly of the calcaneonavicular joint however the subtalar joints can also be involved.18 On plain films secondary signs include an elongated dorsal calcaneus (ant-eater sign) or a hypoplastic talus.19,20 Further imaging is with CT or MRI (Figure 13a and b). On CT bony coalitions reveal a bony bar between the coalesced bone surfaces while non-osseous coalitions will show a loss of joint space with reactive cystic and hypertrophic changes of the underlying bone.21 Similarly on MRI, an osseous coalition will reveal bony continuity. Fibrous and cartilaginous connections are of low and high T2 signal intensities respectively.
Osteochondritis dissecans is a pathological process affecting the articular cartilage and sub-chondral bone with an osteochondral defect in a focal area of bone that undergoes necrosis. As the bone is resorbed the overlying cartilage loses its supporting structure and the underlying bone fragment is displaced into the joint space.14 Proposed causes include micro trauma, ischaemia and genetics.15 It commonly occurs in the knee, however may occur at the elbow or ankle joint. Within the elbow it most commonly involves the capitellum. Plain films may be suggestive however an MRI is required for better delineation and assessment of lesion stability.16 There are four stages of Osteochondritis dissecans on MRI.14 Stage 1 is stable with flattening of the sub-chondral bone and thickening of the overlying articular cartilage. Stage 2 involves a breach of the articular cartilage with low signal change at the base of the lesion due to a stable fibrous connection. Stage 3 and 4 are unstable with high signal change at the base of the fragment and a loose body,
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QUIZ
Figure 13 (a) A teenager diagnosed with tarsal coalition. Sagittal CT reformat shows a non-osseous calcaneonavicular coalition with reduced joint space however no bone bridging. (b) A teenager diagnosed with tarsal coalition. Coronal T2 weighted MRI shows reduced calcaneonavicular joint space with low signal fibrous coalition (solid arrow). 10 Nunley JA, Vertullo CJ. Classification, investigation, and management of midfoot sprains: Lisfranc injuries in the athlete. Am J Sports Med 2002 NoveDec; 30: 871e78. PMID: 12435655. 11 Treatment Lisfranc’s sprain and minimally displaced fractures. Wheeless’ textbook of orthopaedics. http://www.wheeless online.com/ortho/treatment_lisfrancs_sprain_and_minimally_ displaced_frx. 12 David R, Oria RA, Kumar R, et al. Radiologic features of eosinophilic granuloma of bone. AJR Am J Roentgenol 1989 Nov; 153: 1021e26. PMID: 2801420. 13 Stull MA, Kransdorf MJ, Devaney KO. Langerhans cell histiocytosis of bone. Radiographics 1992 Jul; 12: 801e23. PMID: 1636041. 14 Hixon AL, Gibbs LM. Osteochondritis dissecans: a diagnosis not to miss. Am Fam Physician 2000 Jan 1; 61: 151e6, 158. PMID: 10643956. 15 Schenck RC Jr., Goodnight JM. Osteochondritis dissecans. J Bone Joint Surg Am 1996; 78: 439e56. PMID: 8613454. 16 Herman Kan J. Osteochondral abnormalities: pitfalls, injuries, and osteochondritis dissecans. Department of Diagnostic Imaging, Monroe Carell Jr Children’s Hospital at Vanderbilt. 17 Harris RI, Beath T. Etiology of peroneal spastic flat foot. J Bone Joint Surg Br 1948 Nov; 30B: 624e34. PMID: 18894612. 18 Varner KE, Michelson JD. Tarsal coalition in adults. Foot Ankle Int 2000 Aug; 21: 669e72. PMID: 10966365. 19 Oestreich AE, Mize WA, Crawford AH, Morgan RC Jr.. The “anteater nose”: a direct sign of calcaneonavicular coalition on the lateral radiograph. J Pediatr Orthop 1987 NoveDec; 7: 709e11. PMID: 3429658. 20 Sartoris DJ, Resnick DL. Tarsal coalition. Arthritis Rheum 1985 Mar; 28: 331e38. PMID: 31566043. 21 Wechsler RJ, Schweitzer ME, Deely DM, Horn BD, Pizzutillo PD. Tarsal coalition: depiction and characterization with CT and MR imaging. Radiology 1994 Nov; 193: 447e52. PMID: 7972761. 22 Wheelees’ textbook of orthopaedics e calcaneonavicular coalition. http://www.wheelessonline.com/ortho/calcaneonavicular_ coalition.
Initially conservative management is employed. In refractory cases an osseous coalescing bar is amenable to surgical resection. In the presence of degenerative changes across the talar joints an arthrodesis is considered.22 REFERENCES 1 Jarvik JG, Deyo RA. Diagnostic evaluation of low back pain with emphasis on imaging. Ann Intern Med 2002 Oct 1; 137: 586e97. PMID: 12353946. 2 Beutler WJ, Fredrickson BE, Murtland A, Sweeney CA, Grant WD, Baker D. The natural history of spondylolysis and spondylolisthesis: 45-year follow-up evaluation. Spine (Phila Pa 1976) 2003 May 15; 28: 1027e35; discussion 1035. PMID: 12768144. 3 Rankine JJ, Dickson RA. Unilateral spondylolysis and the presence of facet joint tropism. Spine (Phila Pa 1976) 2010 Oct 1; 35: E1111e4. http://dx.doi.org/10.1097/BRS.0b013e3181de8b72. PMID: 20838273. 4 Ralston S, Weir M. Suspecting lumbar spondylolysis in adolescent low back pain. Clin Pediatr (Phila) 1998 May; 37: 287e93. PMID: 9597294. 5 Saifuddin A, Burnett SJ. The value of lumbar spine MRI in the assessment of the pars interarticularis. Clin Radiol 1997 Sep; 52: 666e71. PMID: 9313730. 6 Shahabpour M, De Maeseneer M, Pouders C, et al. MR imaging of normal extrinsic wrist ligaments using thin slices with clinical and surgical correlation. Eur J Radiol 2011; 77: 196e201. PMID: 20599335 7 Davis KW, Blankenbaker DG. Imaging the ligaments and tendons of the wrist. Semin Roentgenol 2010; 45:194e217. PMID: 20483115. 8 Meyer SA, Callaghan JJ, Albright JP, Crowley ET, Powell JW. Midfoot sprains in collegiate football players. Am J Sports Med 1994 MayeJun; 22: 392e401. PMID: 7913587. 9 Curtis MJ, Myerson M, Szura B. Tarsometatarsal joint injuries in the athlete. Am J Sports Med 1993 JuleAug; 21: 497e502. PMID: 8368407.
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