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Schilcher, J., Bernhardsson, M. & Aspenberg, P. (2019). Chronic anterior tibial stress fractures in athletes: No crack but intense remodelling. Scandinavian Journal of Medicine and Science in Sports
Open this publication in new window or tab >>Chronic anterior tibial stress fractures in athletes: No crack but intense remodelling
2019 (English)In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838Article in journal (Refereed) Epub ahead of print
Abstract [en]

PURPOSE: Delayed healing of anterior tibial stress fractures in athletes is related to high tensional forces acting across a putative fracture gap. These forces lead to crack propagation and create strains that exceed tissue differentiation thresholds for new bone to form in the gap. The "dreaded black line" is a radiographic hallmark sign of stress fractures considered to represent a transverse fracture gap. However, whether a fracture gap truly exists at the microscopic level remains unclear. The aim of this study was to describe the area of the "dreaded black line" microscopically and to identify signs of delayed healing.

METHODS: Between 2011 and 2016 we included seven athletes with chronic anterior mid-shaft tibial stress fractures. The fracture site was excised as a cylindrical biopsy. The biopsy was evaluated with micro-CT and histology. The formation of new bone in the defect was evaluated radiographically.

RESULTS: The "dreaded black line" seen on preoperative radiographs in all patients could not be seen on the microscopic level. Instead, the area of the putative crack showed widened resorption cavities, lined with active osteoblasts, and surrounded by immature bone. This area of intense remodelling seemed to create a false impression of a fracture line on radiographs. Complete cortical continuity was restored at the biopsy site at median eight months (range six to 13 months).

CONCLUSION: Tibial stress fractures in athletes normally show no fracture defect, but a region of increased remodelling. The healing process is already ongoing but seems mechanically insufficient. 

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
Stress fracture, fracture healing, histology, tibia
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-157071 (URN)10.1111/sms.13466 (DOI)31102562 (PubMedID)
Funder
Region ÖstergötlandSwedish Research CouncilSwedish National Centre for Research in Sports
Available from: 2019-05-27 Created: 2019-05-27 Last updated: 2019-05-27
Nilsson, A., Alkner, B., Wetterlöv, P., Wetterstad, S., Palm, L. & Schilcher, J. (2019). Low compartment pressure and myoglobin levels in tibial fractures with suspected acute compartment syndrome.. BMC Musculoskeletal Disorders, 20(1), Article ID 15.
Open this publication in new window or tab >>Low compartment pressure and myoglobin levels in tibial fractures with suspected acute compartment syndrome.
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2019 (English)In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 20, no 1, article id 15Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: The intense ischemic pain of acute compartment syndrome can be difficult to discriminate from the pain related to an associated fracture. Lacking objective measures, the decision to perform fasciotomy is often only based on clinical findings and performed at a low threshold. Biomarkers of muscle cell damage might help to identify and monitor patients at risk. In patients with fractures, however, markers of muscle cell damage could be elevated because of other reasons associated with the trauma, which would make interpretation difficult. In a review of all patients who underwent emergency fasciotomy in our health care district we aimed to investigate the decision-making process and specifically the use of biomarkers in patients with and without fractures.

METHODS: In the southeast health care region of Sweden 79 patients (60 men) with fractures (median age 26 years) and 42 patients (34 men) without associated fractures (median age 44 years) were treated with emergency fasciotomy of the lower leg between 2007 and 2016. Differences in clinical findings, p-myoglobin and p-creatine phosphokinase as well as pressure measurements were investigated.

RESULTS: P-myoglobin was analyzed preoperatively in 20% of all cases and p-creatine phosphokinase in 8%. Preoperative levels of p-myoglobin were lower in patients with fractures (median 1065 μg/L, range 200-3700 μg/L) compared with those without fractures (median 7450 μg/L, range 29-31,000 μg/L), p < 0.05. Preoperative intracompartmental pressure was lower in the fracture group (median 45 mmHg, range 25-90 mmHg) compared with those without fractures (median 83 mmHg, range 18-130 mmHg), p < 0.05.

CONCLUSIONS: Biomarkers are seldom used in the context of acute fasciotomy of the lower leg. Contrary to our expectations, preoperative levels of p-myoglobin and intracompartmental pressures were lower in fracture patients. These findings support differences in the underlying pathomechanism between the groups and indicate that biomarkers of muscle cell necrosis might play a more important role in the diagnosis of acute compartment syndrome than previously thought.

Place, publisher, year, edition, pages
BioMed Central, 2019
Keywords
Acute compartment syndrome;Creatine phosphokinase;Fasciotomy;Myoglobin;Tibial fracture
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-153783 (URN)10.1186/s12891-018-2394-y (DOI)000454957500014 ()30611244 (PubMedID)
Note

Funding agencies: Linkoping University; Region Ostergotland; Medical Research Council of Southeast Sweden

Available from: 2019-01-10 Created: 2019-01-10 Last updated: 2019-05-27
Kharazmi, M., Michaëlsson, K., Hallberg, P. & Schilcher, J. (2018). Lateral fixation: an alternative surgical approach in the prevention of complete atypical femoral fractures. European Journal of Orthopaedic Surgery & Traumatology, 28(2), 299-304
Open this publication in new window or tab >>Lateral fixation: an alternative surgical approach in the prevention of complete atypical femoral fractures
2018 (English)In: European Journal of Orthopaedic Surgery & Traumatology, ISSN 1633-8065, E-ISSN 1432-1068, Vol. 28, no 2, p. 299-304Article in journal (Refereed) Published
Abstract [en]

Little evidence is available on how to treat incomplete atypical fractures of the femur. When surgery is chosen, intramedullary nailing is the most common invasive technique. However, this approach is adopted from the treatment of other types of ordinary femoral fracture and does not aim to prevent the impending complete fracture by interrupting the mechanism underlying the pathology. We suggest a different surgical approach that intends to counteract the underlying biomechanical conditions leading to a complete atypical fracture and thus could be better suited in selected cases. Here, we share an alternative surgical approach and present two cases treated accordingly.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
Atypical fracture; Bisphosphonate; Femoral fracture; Fracture prevention; Osteoporosis
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-155813 (URN)10.1007/s00590-017-2041-6 (DOI)28924690 (PubMedID)
Available from: 2019-03-28 Created: 2019-03-28 Last updated: 2019-05-27
Kharazmi, M., Hallberg, P., Schilcher, J., Aspenberg, P. & Michaelsson, K. (2016). Mortality After Atypical Femoral Fractures: A Cohort Study. Journal of Bone and Mineral Research, 31(3), 491-497
Open this publication in new window or tab >>Mortality After Atypical Femoral Fractures: A Cohort Study
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2016 (English)In: Journal of Bone and Mineral Research, ISSN 0884-0431, E-ISSN 1523-4681, Vol. 31, no 3, p. 491-497Article in journal (Refereed) Published
Abstract [en]

Although osteoporotic fracture rates can be reduced by bisphosphonates, prolonged therapy is associated with higher risk of atypical femoral fractures. Ordinary fragility fractures are linked to high mortality rates. We aimed to determine whether atypical femoral fractures also confer excess mortality. Radiographs were reviewed for all patients aged 55 years who had experienced a subtrochanteric or femoral shaft fracture in Sweden in 2008 to 2010. The fractures were classified as either atypical or ordinary. Data on medication use, coexisting conditions, and date of death were obtained from national registers. We estimated multivariable-adjusted relative risks of death after atypical femoral fractures compared with ordinary subtrochanteric or femoral shaft fractures and calculated age- and sex-standardized mortality ratios (SMRs) for atypical and ordinary fractures compared with the population average. During a mean of 4 years of follow-up, 39 of 172 (23%) patients with an atypical fracture had died compared with 588 of 952 (62%) with an ordinary fracture, corresponding to a relative risk of 0.51 (95% confidence interval [CI] 0.38-0.68). The lower risk was evident in both users and nonusers of bisphosphonates. No patient with atypical fracture died in the first year after fracture. Individuals with an ordinary fracture had a higher mortality risk than the general population (SMR=1.82; 95% CI 1.69-1.99), but no excess risk was found in patients with atypical fracture (SMR=0.92; 95% CI 0.65-1.26). We conclude that in contrast to ordinary subtrochanteric and femoral shaft fractures, atypical femoral fractures are not associated with excess mortality. (c) 2015 American Society for Bone and Mineral Research.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2016
Keywords
ATYPICAL FRACTURE; OSTEOPOROSIS; FEMORAL FRACTURE; BISPHOSPHONATES; MORTALITY
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-127577 (URN)10.1002/jbmr.2767 (DOI)000373596800003 ()26676878 (PubMedID)
Note

Funding Agencies|Swedish Research Council

Available from: 2016-05-03 Created: 2016-05-03 Last updated: 2019-05-27
Gustafsson, A., Schilcher, J., Grassi, L., Aspenberg, P. & Isaksson, H. (2016). Strains caused by daily loading might be responsible for delayed healing of an incomplete atypical femoral fracture. Bone, 88, 125-130
Open this publication in new window or tab >>Strains caused by daily loading might be responsible for delayed healing of an incomplete atypical femoral fracture
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2016 (English)In: Bone, ISSN 8756-3282, E-ISSN 1873-2763, Vol. 88, p. 125-130Article in journal (Refereed) Published
Abstract [en]

Atypical femoral fractures are insufficiency fractures in the lateral femoral diaphysis or subtrochanteric region that mainly affect older patients on bisphosphonate therapy. Delayed healing is often seen in patients with incomplete fractures (cracks), and histology of bone biopsies shows mainly necrotic material inside the crack. We hypothesized that the magnitude of the strains produced in the soft tissue inside the crack during normal walk exceeds the limit for new bone formation, and thereby inhibit healink. A patient specific finite element model was developed, based on clinical CT images and high resolution CT images of a biopsy from the crack site. Strain distributions in the femur and inside the crack were calculated for load cases representing normal walk. The models predicted large strains inside the crack, with strain levels above 10% in more than three quarters of the crack volume. According to two different tissue differentiation theories, bone would only form in less than 1-5% cif the crack volume. This can explain the impaired healing generally seen in incomplete atypical fractures. Furthermore, the microgeometry of the crack highly influenced the strain distributions. Hence, a realistic microgeometry needs to be considered when modeling the crack. Histology of the biopsy showed signs of remodeling in the bone tissue adjacent to the fracture line, while the crack itself contained mainly necrotic material and signs of healing only in portions that seemed to have been widened by resorption. In conclusion, the poor healing capacity of incomplete atypical femoral fractures can be explained by biomechanical factors, and daily low impact activities are enough to cause strain magnitudes that prohibit bone formation. (C) 2016 Elsevier Inc. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE INC, 2016
Keywords
Atypical femoral fracture; Finite element analysis; mu CT; Impaired healing
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-130120 (URN)10.1016/j.bone.2016.04.020 (DOI)000377925100015 ()27113528 (PubMedID)
Note

Funding Agencies|Swedish National Centre for Research in Sports; Swedish Foundation for Strategic Research [IB13-0021]; Ostergotland County Council

Available from: 2016-07-12 Created: 2016-07-11 Last updated: 2019-05-27
Schilcher, J., Scheer, J. & Adolfsson, L. (2016). Transclavicular Osseous Sutures for the Treatment of Displaced Distal Clavicular Fractures in Children. Journal of Orthopaedic Trauma, 30(5), E181-E185
Open this publication in new window or tab >>Transclavicular Osseous Sutures for the Treatment of Displaced Distal Clavicular Fractures in Children
2016 (English)In: Journal of Orthopaedic Trauma, ISSN 0890-5339, E-ISSN 1531-2291, Vol. 30, no 5, p. E181-E185Article in journal (Refereed) Published
Abstract [en]

We describe a novel surgical technique for the treatment of displaced distal clavicular fractures in children. These fractures are rare, and recommendations on treatment vary. Conservative treatment might lead to persistent deformity and limitations of function. Previous reports of surgical treatment involve fracture fixation with K-wires. This requires a routine sequential reoperation to remove the implant and has been associated with serious complications in some patients. The surgical technique described here is based on osseous sutures through the clavicular shaft and coracoclavicular ligaments and is found successful for the treatment of distal clavicular fractures in children and may also be feasible for true acromioclavicular dislocations. The main principle of the technique is a fixation of the displaced clavicle through transclavicular drill holes, against the intact inferior periosteal sleeve at the insertion of the coracoclavicular ligaments. No temporary K-wire fixation is needed. To date, we have treated 7 patients with this technique. All fractures healed uneventfully with an excellent functional result and without skeletal deformity.

Place, publisher, year, edition, pages
LIPPINCOTT WILLIAMS & WILKINS, 2016
Keywords
clavicular fracture; children; osseous suture
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-128739 (URN)10.1097/BOT.0000000000000527 (DOI)000374833200007 ()27101169 (PubMedID)
Note

Funding Agencies|Ostergotland County Council, Sweden

Available from: 2016-05-31 Created: 2016-05-30 Last updated: 2019-05-27
Schilcher, J., Sen Howe, T., Ai Png, M., Aspenberg, P. & Koh, J. S. B. (2015). Atypical Fractures are Mainly Subtrochanteric in Singapore and Diaphyseal in Sweden: A Cross-Sectional Study. Journal of Bone and Mineral Research, 30(11), 2127-2132
Open this publication in new window or tab >>Atypical Fractures are Mainly Subtrochanteric in Singapore and Diaphyseal in Sweden: A Cross-Sectional Study
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2015 (English)In: Journal of Bone and Mineral Research, ISSN 0884-0431, E-ISSN 1523-4681, Vol. 30, no 11, p. 2127-2132Article in journal (Refereed) Published
Abstract [en]

We have previously noted a dichotomy in the location of atypical fractures along the femoral shaft in Swedish patients, and a mainly subtrochanteric location of atypical fractures in descriptions of patients from Singapore. These unexpected differences were now investigated by testing the following hypotheses in a cross-sectional study: first, that there is a dichotomy also in Singapore; second, that the relation between subtrochanteric and diaphyseal location is different between the two countries; third, that the location is related to femoral bow. The previously published Swedish sample (n = 151) was re-measured, and a new Singaporean sample (n = 75) was established. Both samples were based on radiographic classification of all femoral fractures in women above 55 years of age. The distance between the fracture line and the lesser trochanter was measured. Femoral bow was classified as present or absent on frontal radiographs. Frequency distribution of the measured distances was analyzed using the Bayesian information criterion to choose the best description of the observed variable distribution in terms of a compilation of normally distributed subgroups. The analysis showed a clear dichotomy of the fracture location: either subtrochanteric or diaphyseal. Subtrochanteric fractures comprised 48% of all fractures in Singapore, and 17% in Sweden (p = 0.0001). In Singapore, femoral bow was associated with more fractures in the diaphyseal subgroup (p = 0.0001). This was not seen in Sweden. A dichotomous location of atypical fractures was confirmed, because it was found also in Singapore. The fractures showed a different localization pattern in the two countries. This difference may be linked to anatomical variations, but might also be related to cultural differences between the two populations that influence physical activity. (c) 2015 American Society for Bone and Mineral Research

Place, publisher, year, edition, pages
WILEY-BLACKWELL, 2015
Keywords
OSTEOPOROSIS; BIOMECHANICS; ANTIRESORPTIVES; RADIOLOGY; INJURY; FRACTURE HEALING
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-122651 (URN)10.1002/jbmr.2547 (DOI)000363286900020 ()25950861 (PubMedID)
Note

Funding Agencies|Swedish Research Council [VR 2009-6725]; Ostergotland County Council; King Gustaf V and Queen Victoria Free Mason Foundation

Available from: 2015-11-16 Created: 2015-11-13 Last updated: 2019-05-27
Schilcher, J. (2015). High revision rate but good healing capacity of atypical femoral fractures. A comparison with common shaft fractures. Injury, 46(12), 2468-2473
Open this publication in new window or tab >>High revision rate but good healing capacity of atypical femoral fractures. A comparison with common shaft fractures
2015 (English)In: Injury, ISSN 0020-1383, E-ISSN 1879-0267, Vol. 46, no 12, p. 2468-2473Article in journal (Refereed) Published
Abstract [en]

Introduction: Healing of complete, atypical femoral fractures is thought to be impaired, but the evidence is weak and appears to be based on the delayed healing observed in patients with incomplete atypical fractures. Time until fracture healing is difficult to assess, therefore we compared the reoperation rates between women with complete atypical femoral fractures and common femoral shaft fractures. Methods: We searched the orthopaedic surgical registry in Ostergotland County for patients with subtrochanteric and femoral shaft fractures (ICD-10 diagnosis codes S72.2, S72.3 and M84.3F) between January 1st 2007 and December 31st 2013. Out of 895 patients with surgically treated femoral shaft fractures, 511 were women 50 years of age or older. Among these we identified 24 women with atypical femoral shaft fractures, and 71 with common shaft fractures. Results: Reoperations were performed in 6 and 5 patients, respectively, odds ratio 4.4 (95% CI 1.2 to 16.1). However, 5 reoperations in the atypical fracture group could not be ascribed to poor healing. In 3 patients the reoperation was due to a new fracture proximal to a standard intramedullary nail. In 2 patients the distal locking screws were removed due to callus formation that was deemed incomplete 5 months post-operatively. The one patient with poor healing showed faint callus formation at 5 months when the fracture was dynamised and callus remained sparse at 11 months. Among patients with common shaft fractures, 2 reoperations were performed to remove loose screws, 2 because of peri-implant fractures and 1 reoperation due to infection. Discussion: Reoperation rates in patients with complete atypical femoral fractures are higher than in patients with common shaft fractures. The main reason for failure was peri-implant fragility fractures which might be prevented with the use of cephalomedullary nails at the index surgery. Fracture healing however, seems generally good. A watchful waiting approach is advocated in patients with fractures that appear to heal slowly. (C) 2015 Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2015
Keywords
Atypical femoral fracture; Delayed healing; Bisphosphonate; Fracture healing
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-123772 (URN)10.1016/j.injury.2015.09.031 (DOI)000366020000028 ()26477344 (PubMedID)
Note

Funding Agencies|Ostergotland County Council, Sweden

Available from: 2016-01-11 Created: 2016-01-11 Last updated: 2019-05-27
Schilcher, J., Koeppen, V., Aspenberg, P. & Michaelsson, K. (2015). Risk of atypical femoral fracture during and after bisphosphonate use Full report of a nationwide study. Acta Orthopaedica, 86(1), 100-107
Open this publication in new window or tab >>Risk of atypical femoral fracture during and after bisphosphonate use Full report of a nationwide study
2015 (English)In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 86, no 1, p. 100-107Article in journal (Refereed) Published
Abstract [en]

Background and purpose - Use of bisphosphonates in women is associated with higher risk of atypical femoral fractures. The risk in terms of timing of use and type of bisphosphonate, and in men, remains unclear. Patients and methods - We reviewed radiographs of 5,342 Swedish women and men aged 55 years or more who had had a fracture of the femoral shaft in the 3-year period 2008-2010 (97% of those eligible), and found 172 patients with atypical fractures (93% of them women). We obtained data on medication and comorbidity. The risk of atypical fracture associated with bisphosphonate use was estimated in a nationwide cohort analysis. In addition, we performed a case-control analysis with comparison to 952 patients with ordinary shaft fractures. A short report of the findings has recently been presented (Schilcher et al. 2014a). Here we provide full details. Results - The age-adjusted relative risk (RR) of atypical fracture associated with bisphosphonate use was 55 (95% CI: 39-79) in women and 54 (CI: 15-192) in men. In bisphosphonate users, women had a 3-fold higher risk than men ( RR = 3.1, CI: 1.1-8.4). Alendronate users had higher risk than risedronate users (RR = 1.9, CI: 1.1-3.3). The RR after 4 years or more of use reached 126 (CI: 55-288), with a corresponding absolute risk of 11 (CI: 7-14) fractures per 10,000 person-years of use. The risk decreased by 70% per year since last use. Interpretation - Women have a higher risk of atypical femoral fracture than men. The type of bisphosphonate used may affect risk estimates and the risk decreases rapidly after cessation.

Place, publisher, year, edition, pages
Informa Healthcare, 2015
National Category
General Practice
Identifiers
urn:nbn:se:liu:diva-114568 (URN)10.3109/17453674.2015.1004149 (DOI)000348367000016 ()25582459 (PubMedID)
Note

Funding Agencies|Swedish Research Council [VR 2009-6725]; Linkoping University; Ostergotland County Council; King Gustaf V and Queen Victoria Freemason Foundation; Eli Lilly Co.

Available from: 2015-03-02 Created: 2015-02-26 Last updated: 2019-05-27
Aspenberg, P. & Schilcher, J. (2014). Atypical femoral fractures, bisphosphonates, and mechanical stress. Current osteoporosis reports, 12(2), 189-193
Open this publication in new window or tab >>Atypical femoral fractures, bisphosphonates, and mechanical stress
2014 (English)In: Current osteoporosis reports, ISSN 1544-1873, Vol. 12, no 2, p. 189-193Article in journal (Refereed) Published
Abstract [en]

Atypical fractures are stress fractures occurring in the femoral shaft and closely related to bisphosphonate use. We here discuss their radiographic definition and different putative etiologies, apart from mechanical stress. Long time reduction of skeletal remodeling because of bisphosphonate use is thought to allow time for the bone to deteriorate mechanically, resulting in reduced toughness. However, the risk of atypical fracture diminishes rapidly after cessation of treatment, which suggests more acute effects of bisphosphonate use. Microdamage normally accumulates at areas of high stress. Possibly, ongoing bisphosphonate use reduces the ability to resorb and replace areas of microdamage by targeted remodeling. This could lead to crack propagation beyond a point of no return, ending in macroscopic stress fracture.

Place, publisher, year, edition, pages
Springer, 2014
Keywords
Atypical femoral fractures, Bisphosphonates, Bone remodeling, Osteoporosis, Bone fragility
National Category
Orthopaedics
Identifiers
urn:nbn:se:liu:diva-111392 (URN)10.1007/s11914-014-0200-9 (DOI)000347283600007 ()24615358 (PubMedID)
Available from: 2014-10-16 Created: 2014-10-16 Last updated: 2019-05-27Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0677-9265

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