Young and Old Bone: Early signs of disturbed fracture healing.

Transcription

1 Young and Old Bone: Early signs of disturbed fracture healing. Poster No.: C-2502 Congress: ECR 2017 Type: Educational Exhibit Authors: B. V. G. Pinedo, R. García Buen-Abad, R. CHOZA CHENHALLS, D. E. Reyes Vazquez, A. Cruz, M. F. ortiz, P. M Dautt Medina ; Jiutepec/MX, Mexico City, D./MX, Mexico city, D.F./MX, Distrito Federal/MX, mexico DF/MX, Mexico city/mx, 7 MEXICO, DF/MX Keywords: Bones, Trauma, Musculoskeletal bone, CT, MR, Fluoroscopy, Instrumentation, Education, Demineralisation-Bone, Osteoporosis DOI: /ecr2017/C-2502 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 22

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3 Learning objectives 1. Learning objectives The purpose of our educational exhibit is to: 1.Review the age-dependent changes in bone and the current radiological evaluation. 2. Learn the key Imaging findings of the fracture healing stages and its biological correlation. 3. Recognize the pathways of disturbed fracture healing (types of non-unions and clinical relevance of early diagnosis) and acknowledge the role of radiography in assessing the early signs in the elderly and pediatric population. 4. Review the current multimodality imaging techniques in disturbed fracture healing. Page 3 of 22

4 Background Background 2.Radiological evaluation of bone growth and the age-dependent changes. The shape of long bones modifies with age. Early in life, the bone diameter changes, starting with a uniform cortical thickness (Fig. 1) and progresses to an ellipsoid shape (Figs. 2-3), this process is known as "cortical drift". Changes in periosteal and endosteal remodeling causes augmented resorption in the endosteal surface with incresed bone formation at the periosteal surface, modifying the diameter. The cortical drift can be evaluated in plain radiography in early childhood and prepuberal growth, as well as in the elderly, resulting in a weakened bone with thin cortex (Fig. 4) Page 4 of 22

5 Images for this section: Fig. 1: Early in life the cortical thickness is uniform. Page 5 of 22

6 Fig. 2: 7 years old plain film of forearm. Note the drift in anterior-posterior direction is larger in childhood from 2 to 9 years. Page 6 of 22

7 Fig. 3: 14 years old plain film of forearm. Note the drift in medial- lateral direction is larger in the prepuberal stage. Page 7 of 22

8 Fig. 4: 81 years old plain film of elbow. Notice the thining of cortices due to endosteal remodeling. Page 8 of 22

9 Findings and procedure details 3. Indirect fracture healing stages and its imaging correlation: Inflammation, soft callus formation, hard callus formation and remodeling. Fracture healing can be divided in: Primary or direct: Occurs when there is total stability and the bone heals due to internal remodeling. Secondary or indirect: The healing process is due to callus formation with partial stability (flexible fixation) and it occurs with intramembraneous and endochondral bone formation. Secondary bone healing can be divided into four stages: Inflammation: (1-7 days postfracture). Initially, there is hematoma formation which is gradually replaced by granulation tissue. In plain radiography the only findings are swelling of soft tissues with fracture ends. (Fig.5). Soft callus formation (2-3 weeks postfracture). Pain and swelling decline as soft callus is generated. The granulation tissue is replaced by fibrous tissue and cartilage. The upgrowth of vessels is stimulated into the calcified callus. This process happens in a centripetal fashion. At the end of this stage stability can prevent shortening, however angulation may occur. In plain radiography the new bone formations can be visualized as a thick radiopaque mass around the fracture endings, but the angulation or non alignment of bone fragments persists. (Fig.6). Hard callus formation: (3-4 months). During this process there is complete substitution of callus into calcified tissue through intramembraneous and endochondral ossification. The new bone formation starts peripherally and moves towards the center of the fracture gap through time. In plain radiography there is visible bone alignment with loss of fracture angulation, the borders of the fracture appear "smoother" although irregularity of bone cortical might persist. (Fig.7). Remodeling: (months to years) During this process there is conversion of woven bone into lamellar bone until the bone has totally returned to its original morphology with restoration of the medullary canal. In plain radiography the epiphyses gradually align and residual angulation may be slowly corrected. The cortical surface appears smooth. (Fig. 8) 4. Pathways of disturbed fracture healing. (radiography) Delayed union, Non-union and Malunion. Page 9 of 22

10 Delayed union: The bone healing process takes twice as long as expected for the fracture. The fact that a bone is delayed in its union does not mean that it will become a nonunion. Malunion: The healing process occurs in the wrong position and there is partial compensation by remodeling. (Fig. 9 ). Non-union: Currently, there is not an accepted standarized definition. The FDA defines it as a fracture over 9 moths old without radiographic signs of healing in the last three months. The remodeling and healing process is affected by excessive or lower strain or a wide/broad gap. Nonunion is one end result of a delayed union, and differentiating between these two entities is sometimes difficult. 5. Types of Nonunions and clinical relevance: Hypertrophic, Oligotrophic, Atrophic, Comminuted, and Infected. Hypervascular nonunion: Also known as hypertrophic nonunion. The fractures endings are hypervascular and due to excessive micromotion at the site of fracture, or a broad gap, an excessive bone formation occurs. (Fig.10) Infection: Occult infection is a common cause of non union in fractures, it can only be excluded by taking the pertinent samples in every case of non union. Therefore this diagnosis might be retarded in the absence of radiolgical signs. It must be emphasized that the current classifications of non union are based on radiological signs and do not consider infection. 6. Early signs of disturbed fracture healing in the elderly and pediatric population: key imaging findings in plain radiography of nonunions. Hypertrophic signs: (Fig 10-11) Abundant callus formation Persistence of fracture line. Sealing off of the medullary cavity with sclerosis at the edge of the fractured bone. Regional osteoporosis above and below the fracture site. Bony ends rounded. Atrophic signs: (Fig ) Persistence of fracture line with no callus formation. Page 10 of 22

11 Large gap exists between the ends. After internal fixation or open reduction persistence of line fracture and demonstration of excessive stiffness in stress films. 7. Current multimodality imaging techniques (Radiography, CT and MRI) used in assessment of disturbed fracture healing. Radiography: Conventional radiographs are the study of first choice when the non union is already diagnosed and the fracture fragments are smooth and sclerotic. The plain films are helpfull evaluating the following characteristics: Anatomic location, healing process, bone density, surface of fracture, status of fixation materials, and developing deformities. CT and MRI: Despite plain radiographs are the imaging technique of choice when assessing bone healing process, they are not always sufficient. The fixation devices and sclerotic bone can obscure the fracture site. The CT scans are quite useful to objectively assess the percentage of bridging bone and is the best imaging method to evaluate intraarticular non unions. MRI is the study of choice when infection is suspected. Page 11 of 22

12 Images for this section: Fig. 5: Inflammatory phase: In this phase the findings are swelling of soft tissue and clear ends of fracture as shown in this oblique fracture in the femoral diaphysis. Page 12 of 22

13 Fig. 6: Soft callus formation. In plain film there is visible new bone formation, non alligment of bone fragments persist. Page 13 of 22

14 Fig. 7: Hard callus formation: During this stage there is visible bone allignment, irregularity in bone cortical persists. Page 14 of 22

15 Fig. 8: Remodeling: In this phase the fracture endings are totally aligned and the cortical surface appears smooth. Page 15 of 22

16 Fig. 9: 78 years old plain elbow film. The distal humeral transverse fracture (Fig. 9) with malalignment of bone ends is compensated by remodeling. Page 16 of 22

17 Fig. 10: Radiographs of a hypertrophic tibial non union. Plain film shows a transverse proximal tibial fracture with medial displacement, (left) a transverse fracture is also seen in the proximal fibula metaphysis in a 30 year old patient. In further evaluations after 1 month (middle) and 7 months (right) the fracture line persists with abundant callus formation. Notice the sealing off of the medullary cavity with sclerosis at the edge of the fractured bone. Page 17 of 22

18 Fig. 11: Radiographs of a hypertrophic tibial and fibular non union. Plain film shows an oblique distal tibial and fibular fracture with medial displacement in an 18 year old patient (left). In further evaluations after 8 months (right) there is persistence of fracture lines and callus formation. The bony ends are rounded. Page 18 of 22

19 Fig. 12: Radiographs of an atrophic radial head non union. Plain film shows an epiphysis radial head fracture in a12 year old patient (left). In further evaluations after 6 months (right) there is persistence of fracture lines with no callus formation. Notice the gap persistence between bone ends. Page 19 of 22

20 Fig. 13: Radiographs of an atrophic distal femoral non union. Plain film shows a distal diaphysis oblique comminute fracture in a 40 year old patient 1 month after instrumentation (left). In further evaluations after 10 months (right) there is persistence of fracture lines with no callus formation. Page 20 of 22

21 Conclusion A non union by definition is a fracture that will not heal. The radiologist should be familiar with the imaging findings of hypertrophic, oligotrophic and atrophic non union to achieve an early diagnostic. Page 21 of 22

22 References Normal 0 21 false false false ES-MX JA X-NONE A.L. Boskey* And R. Coleman, Aging And Bone, J Dent Res 89(12): , Saam Morshed, Current Options For Determining Fracture Union, Advances In Medicine Volume 2014 (2014), Article ID , 12 Pages Keita Ito, Stephan M Perren, Manual Of Fracture Management-Hand David M. Nunamaker, Frederic W. Rhinelander, And R. Bruce Heppenstall, Delayed Union, Nonunion, And Malunion Mark R. Brinker, M.D. and Daniel P. O'Connor, Ph.D., Nonunions: Evaluation and Treatment L. Mills, J. Tsang, G. Hopper, G. Keenan, A. H. R. W. SimpsonThe multifactorial aetiology of fracture nonunion and the importance of searching for latent infection Page 22 of 22