FATIGUE, INSUFFICIENCY, AND PATHOLOGIC FRACTURES

Prevalence and Characteristics of Pathological Fractures in Patients Referred to Specialist Palliative Care: A Retrospective Study From India

Background: Prevalence of pathological fractures in palliative care is less studied. This study aimed to determine the annual prevalence of pathological fractures and describe the characteristics and treatments in patients with pathological fractures referred to a specialist palliative care clinic in a tertiary care cancer center in India. Methods: Data of adult cancer patients newly referred to the specialist palliative care clinic over 1 year with a clinico-radiological diagnosis of pathological fracture was included. Key outcomes of interest were annual prevalence, clinical characteristics, symptoms and treatments offered. Results: 75 out of 5800 (1.29%) patients newly referred to the clinic over 1 year had pathological fractures. Lung cancer was the most common primary diagnosis (n = 23).Dorsal spine (n = 25) was the most common site of fracture. Pain was the predominant symptom. Mean pain score was 7.04(SD = 1.75) and 42 patients (56%) required strong opioids for analgesia. Only 11 (16%) patients underwent surgical fixation. Median duration from diagnosis of cancer to occurrence of fracture was found to be 329 days. Treatment goals changed to best supportive care in 33 patients (44%) post fracture. Patients with bone and soft tissue neoplasms and those who received only chemotherapy previously had a higher risk of occurrence of fractures. Conclusion: Annual prevalence of pathological fractures in patients referred to the specialist palliative care clinic was 1.29%. It was associated with significant symptom burden and affected oncological treatments. Close monitoring of patients with bone metastases is crucial and proactive implementation of prophylactic measures to prevent such skeletal related events is warranted.

[Contemporary imaging examinations for (suspected) stress fractures]

Stress fractures belong to the group of atraumatic fractures. A low-impact and repetitive load is the underlying cause and no fracture would occur under physiological circumstances. The conventional X‑ray examination remains the initial imaging modality when a stress fracture is suspected. In contrast, magnetic resonance imaging (MRI) is the gold standard and is also used to rule out other pathological changes. Computed tomography (CT) should be included if the MRI findings are unclear. New techniques, such as dual energy computed tomography (DECT) and magnetic resonance bone imaging (MR bone) should be used more frequently in practice in the future and become increasingly more important for the correct diagnosis.

[Sacral H-shaped fractures between traumatic, insufficiency and fatigue fractures : Similarities, differences and controversies]

In the basic entirety of stress fractures, insufficiency fractures are defined as fractures caused by prolonged normal or physiological loading of a bone with insufficient elastic resistance. This clearly distinguishes it from fatigue fractures, in which excessive loads are continuously applied to a bone with normal elastic resistance. According to Pentecost (1964) both entities of stress fracture result from "the inherent inability of the bone to withstand stress applied without violence in a rhythmical, repeated, subthreshold manner". This distinguishes them from acute traumatic fractures. In the clinical routine these differences are not always so clearly presented. The example of the H‑shaped sacral fracture is used to illustrate the relevance of a clear terminology. In this context, current controversies in the treatment of sacral insufficiency fractures are discussed.

Bilateral insufficiency fracture of coracoid process: A rare case report

A 69-year-old man was admitted to the hospital for a left femoral neck fracture. A preliminary chest computed tomography scan showed no coracoid process fracture. The patient had no history of trauma during his hospitalization. However, subsequent in-hospital computed tomography scan revealed bilateral coracoid process fracture. The patient underwent hip replacement surgery for femoral neck fracture, while conservative treatment was administered for the bilateral coracoid process fracture. After 1-year follow-up, the patient was diagnosed with bilateral insufficiency fracture of coracoid process after ruling out other types of fractures. The fractures did not heal while functions in both shoulders were adequate. Insufficiency fracture should be considered when fractures occur without trauma, especially in the presence of associated risk factors such as chronic renal failure and osteoporosis. For bilateral insufficiency fracture of coracoid process, conservative treatment is acceptable.

Insufficiency fracture of the supra-acetabulum that required differentiation from a pathological fracture secondary to a malignant bone tumor: a case report

Background

The supra-acetabulum is a common site for malignant bone tumors, which can be difficult to differentiate from insufficiency fractures. We report a rare case of a stress fracture of the supra-acetabulum that required differentiation from a malignant bone tumor.

Case presentation

A 74-year-old Japanese man presented to the hospital because of right hip joint pain. X-rays showed no obvious abnormalities. Magnetic resonance imaging showed an abnormality in the right supra-acetabulum, and he was referred to our department. A linear, low-signal region and its surrounding equal signal region were observed at the same site in the T1-weighted image, and a linear low-signal region and high signal region were observed in the surrounding area in the T2-weighted image. On the contrast-enhanced magnetic resonance imaging, the lesion was still unclear and the whole area was gradually enhanced. A computed tomography-guided needle biopsy was performed, but no tumor cells were observed, therefore the lesion was presumed to be a fracture healing. The bone density was 66% for the lumbar spine (young adult mean, L2–4), and blood biochemistry showed an increase in alkaline phosphatase and total type I procollagen N-terminal propeptide.

Conclusion

This case was diagnosed as an insufficiency fracture of the supra-acetabulum in a male patient with primary osteoporosis by biopsy specimen. Initially, a pathological fracture associated with a malignant lesion was considered. On magnetic resonance imaging, the boundary around the fracture line was unclear and a signal change that was gradually enhanced by gadolinium was observed. This is likely to be bone marrow edema associated with the stress fracture, and we believe this to be a useful finding that may help in differentiating a stress fracture from a pathological fracture secondary to a malignant lesion.

Resource Consumption and Remuneration Aspects in Navigated Screw Fixation Procedures with or without Additional Sacroplasty for Fragility Fractures of the Sacrum-A Prospective Clinical Study

Surgical treatment for sacral fragility fractures using navigation-assisted screw fixation (NSF) is a modern, technically demanding procedure. Additional sacroplasty (ASP) has been shown to provide only insignificant clinical benefits for patients. This investigation highlights procedural economic aspects and evaluates results with regard to resource scarcity in order to be able to decide, whether ASP has a justification in NSF procedures beyond clinical aspects. From February 2011 to May 2017, all individuals with sacral fragility fractures surgically treated using 3D-fluoroscopy for NSF (n = 26) or NSF + ASP (n = 26) were enrolled. Outcome parameters were operative time, 3D-/2D-radiation dose, 2D-fluoroscopy time, material costs and reimbursement. In the two groups, a total of 52 individuals with 124 fragility fracture sites in sacral vertebrae I and II were surgically treated with similar numbers of screws inserted (p ≈ 0.679) requiring similar 3D- (p ≈ 0.546) and 2D-fluoroscopy radiation doses (p ≈ 0.236). In procedures with ASP, average 2D-fluoroscopy time (46.6 s vs. 32.7 s, p ≈ 0.004), and mean surgical duration (119 min vs. 96 min, p ≈ 0.011) were significantly longer. Mean implant costs (EUR 668.68 vs. EUR 204.34, p < 0.001), and reimbursement (EUR 8416.01 vs. EUR 6584.49, p ≈ 0.006) were significantly higher. Although comparison of costs and reimbursements indicated a positive financial balance, profitability was not confirmed, because financial expense for extended operative time prevented an economic advantage of procedures with ASP in this investigation. A formula was developed based on presented study data to allow similar economical decisions in other health care systems or institutions with differing resource costs.

Superiority of MRI for Evaluation of Sacral Insufficiency Fracture

Study Design: Retrospective observational study. Background: Sacral insufficiency fractures (SIF) are relatively rare fractures and difficult to diagnose on plain radiographs. The primary objective of the present study was to evaluate the role of lumbar magnetic resonance imaging (MRI) for the diagnosis of SIF. The secondary objective was to identify the classification of SIF by computed tomography (CT). Methods: A total of 77 (Male 11, female 66, mean 80.3 years) people were included in this study. Inclusion criteria for this study were: age ≥ 60 years and no history of high energy trauma. Exclusion criteria were high energy trauma and a current history of malignancy. Differences in the fracture detection and description in the various radiologic procedures were evaluated. Fracture patterns were evaluated with CT. The detection rates of additional pathologies in the MRI of the pelvis and lumbar spine were also recorded. Results: The sensitivities for SIF were 28.5% in radiographs and 94.2% in CT, and all fractures were detected in MRI. MRI showed a more complex fracture pattern compared with CT in 65% of the cases. We observed 71.4% of single SIFs, 9.1% with other spinal fractures, 13.0% with other pelvic fractures, and 7.8% with other fractures. According to the SIF fracture pattern, the H/U type was 40.2%, transverse type was 33.7%, λ/T type was 24.7%, unilateral vertical type was 1.3%, and bilateral vertical type was 0%. Conclusions: an MRI of the lumbar spine including the sacrum with a coronal fat-suppressed T2-weighted image is useful for elderly patients with suddenly increasing low back pain at an early stage. This procedure improves an early SIF detection, recognition of concomitant pathologies, and adequate treatment for the patients.

Bilateral stress fracture of the femoral neck in association with simultaneously developing osteonecrosis of the femoral head: a case report

Background

Femoral neck stress fractures are rare and often recognized as overuse injuries that occur in young athletes or military personnel. A case following osteonecrosis of the femoral head is quite rare; even more uncommon is its occurrence in the bilateral hips. Magnetic resonance imaging has been established as the preferred tool for diagnosing nondisplaced femoral neck stress fracture due to overuse injury. Magnetic resonance imaging was also useful to detect the initial lesion even in this case, although the etiology was different between overuse injury and insufficiency fracture.

Case presentation

A 41-year-old Japanese woman diagnosed with bilateral early stage idiopathic osteonecrosis of the femoral head was observed non-weight-bearing as much as possible using a stick. However, her pain and difficulty in walking progressed. Bilateral femoral neck stress fractures were subsequently detected by magnetic resonance imaging. The fracture initially appeared as a spot of bone marrow edema at the medial site of the femoral neck, and then developed into a fracture line. The patient underwent internal fixation of both hips with sliding hip screws to stabilize the stress fractures. In addition, the preparatory reaming served as core decompression of the femoral heads, as well as being treatment for osteonecrosis. Her bone mineral density and 25-hydroxy vitamin D values were low for her age. We administered eldecalcitol and teriparatide acetate. Her symptoms mostly improved, and the fracture lines and necrotic lesions on magnetic resonance imaging reduced at 5 months after the surgery.

Conclusions

Bilateral femoral neck stress fractures are a very rare condition and are often missed. It is important to listen to the patient’s complaints and perform an appropriate examination. We encountered a case of bilateral femoral neck stress fracture that occurred in a patient with early stage osteonecrosis of the femoral head, and were able to observe progression of stress fracture since before fracture occurred. This is considered to be the first report to capture imaging changes before and after the onset.

Fatigue Acetabular Fracture after Lumbopelvic Instrumented Fusion in Elderly

Purpose

Only several cases of acetabular "fatigue"/insufficiency fractures have been reported in elderly patients with osteoporosis. However, fatigue acetabular fracture below lumbopelvic fixation has not been published. This review reports on the frequency and mechanisms of acetabular fatigue fractures in elderly individuals, including postmenopausal osteoporosis, and presents a case of an acetabular "fatigue" fracture in association with lumbopelvic fusion.

Methods

We report on a 71-year-old postmenopausal woman who underwent in our department a L2-pelvis instrumented fusion for failed lumbar decompression and interbody fusion performed in another institution. For at least one year, the patient was receiving antiosteoporotic treatment (Alendronate plus Calcium and Vitamin D) and was fully ambulatory without limping. Eighteen months following our surgery, the patient sought again our department because of increasing pain in her right hip and limping without trauma.

Results

The physical examination disclosed painful passive motion in her right hip. The roentgenograms and CT-scans disclosed a transverse acetabular fracture with radiolucencies around both iliac screw tips, particularly the right. Additionally, a severe compression fracture of the 12^th thoracic vertebral body and upper endplate of the L2 vertebra was disclosed. We recommended open stabilization of the acetabulum and T12 and L2 vertebrae. Immediately before the planned surgeries, the patient had a serious heart infarct, and thus, surgeries were canceled by the patient's cardiologist because of the high perioperative risk. The patient and relatives denied further surgeries because of the heart disease. In the final telephone call and CT and roentgenographic evaluation that went to us after request, there was an acetabular pseudarthrosis in the right hip without however associated complaints. Since surgery was not accepted, the patient was prescribed Denosumab injection therapy plus Vitamin and Calcium supplement.

Conclusion

This case report emphasizes the significance of follow-up observation of elderly patients with postmenopausal osteoporosis following lumbopelvic fusions, for possible fatigue acetabular and vertebral fractures. The authors speculate that this extremely rare acetabular "fatigue"/insufficiency fracture should be the result of increased repetitive mechanical forces acting around the acetabulum in association with osteoporosis.

[Radiological aspects in the diagnostics of pathological fractures]

Radiological diagnostics play a key role in the identification and assessment of pathological fractures. Conventional projection radiography is still the mainstay of imaging investigations. With knowledge of the patient history, the morphology and location of a fracture as well as concomitant findings, such as osteolysis or periosteal reactions can add valuable information on the origin of the fracture. Magnetic resonance imaging (MRI) is the imaging modality of choice for the local diagnostic work-up as it provides insights into the medullary cavity and visualizes potential extraosseous tumor tissue in the fracture zone. Computed tomography (CT) imaging provides valuable information on the morphological features of fractures and is useful for the planning of the surgical approach. Furthermore, it is the modality of choice for whole-body staging. In most cases of pathological fractures without a history of malignancy, a biopsy and histological work-up is recommended.

Bilateral Tibial Stress Fractures and Osteoporosis in a Young Patient

Stress fractures result from microscopic bone injury due to repetitive submaximal stress and include fatigue and insufficiency fracture components. Fatigue fractures generally occur in runners and athletes and are caused by abnormal physical load on the bone. On the other hand, insufficiency fractures are generally seen in the elderly secondary to osteoporosis, typically involving the pelvis and surrounding bones. Insufficiency fracture occurs as a result of normal loading in the abnormal bone. In this case report, we describe a young patient with bilateral tibial stress fractures with both fatigue and insufficiency components.

Spontaneous subcapital femoral neck fracture complicating osteonecrosis of femoral head

Spontaneous subcapital fracture (SSF) of femoral neck in pre-existent osteonecrosis of femoral head (ONFH) is a rare presentation. Only a few cases have been reported so far and majority of them have been reported to have unilateral hip involvement. We retrospectively reviewed clinical-radiological data of 10 patients (12 hips) with SSF complicating ONFH. All of them underwent uncemented total hip arthroplasty. All the available publications in the English language based medical literature were critically reviewed and results were summarized. The median age of presentation was 32 years (range : 24 years to 61 years). They were followed up for a mean duration of 25 months (range : 12 months to 59 months). The most common risk factor was corticosteroid consumption (7 out of 10 patients). All except one (modified Ficat and Arlet stage II) belonged to advanced stage of ONFH {stage III 3 patients (3 hips), stage IV 6 patients (8 hips)}. The mean time lag of ONFH to presentation was 22.3 months (range : 5 months to 60 months), and SSF to presentation was 13.8 days (range : 1 day to 28 days). Mean pre- operative Harris Hip Score was 10.8 (range : 8 to 14), which improved to 93 (range : 91 to 96) after total hip arthroplasty when last followed up (p<0.05). Corticosteroids induced ONFH has a propensity to develop SSF. This entity should find a place in existing classification system.

Atraumatic fractures of the femur

Atraumatic fractures of femur, although not as common as traumatic fractures, are frequently encountered in the clinical practice. They present with non-specific symptoms and can be occult on initial imaging making their diagnosis difficult, sometimes resulting in complications. Overlapping terminologies used to describe these fractures may hamper effective communication between the radiologist and the clinician. In this article, we review various atraumatic fractures of femur, terminologies used to describe them, their imaging findings and differential diagnosis. The article also describes the aetiology, pathophysiology and relevant biomechanics behind these fractures. An approach to atraumatic femoral fractures has been outlined.

Risk Factors Associated With Foot and Ankle Insufficiency Fractures in Postmenopausal Sedentary Women

BACKGROUND

Insufficiency fractures occur in bones with low elastic resistance. In contrast to stress fractures, which affect normal bones and have been extensively studied, insufficiency fractures of the foot and ankle have been the subject of little research. The objective of this study was to identify risk factors associated with the development of foot and ankle insufficiency fractures.

METHODS

The study included 55 postmenopausal sedentary women with foot and ankle insufficiency fractures and 51 women in the control group. The data collected were the fracture site, body mass index, use of corticosteroids, T scores of the femur and lumbar spine measured by bone densitometry, and serum 25-OH vitamin D level. The calcaneal pitch (CP), talar-first metatarsal, and metatarsus adductus (MA) angles were measured on radiographs.

RESULTS

In 49 patients (89%), fractures occurred in the metatarsals. All metatarsals were affected, and the most common fracture site was the base of the fifth metatarsal, with 21 cases (33%). Twenty patients (36%) in the study group reported chronic use of corticosteroids and had lower bone mineral density levels than controls (P < .05). The factors associated with fracture development (P < .05) were the CP and MA angles and low lumbar bone mineral density.

CONCLUSION

Insufficiency fractures in this population were associated with low bone mineral density and unfavorable biomechanical characteristics such as pes cavus and metatarsus adductus.

LEVEL OF EVIDENCE

Level IIIB, case-control study.

Screw-in-screw fixation of fragility sacrum fractures provides high stability without loosening-biomechanical evaluation of a new concept

Surgical treatment of fragility sacrum fractures with percutaneous sacroiliac (SI) screw fixation is associated with high failure rates. Turn-out is detected in up to 20% of the patients. The aim of this study was to evaluate a new screw-in-screw implant prototype for fragility sacrum fracture fixation. Twenty-seven artificial hemipelvises were assigned to three groups (n = 9) for instrumentation of an SI screw, the new screw-in-screw implant prototype, ora transsacral screw. Before implantation, a vertical osteotomy was set in zone 1 after Denis. All specimens were biomechanically tested to failure in upright position. Validated setup and test protocol were used for complex axial and torsional loading applied through the S1 vertebral body to promote turn-out of the implants. Interfragmentary movements were captured via optical motion tracking. Screw motions were evaluated by means of triggered anteroposterior X-rays. Interfragmentary movements and implant motions were significantly higher for SI screw fixation compared to both transsacral and screw-in-screw fixations. In addition, transsacral screw and screw-in-screw fixations revealed similar construct stability. Moreover, screw-in-screw fixation successfully prevented turn-out of the implant that remained during testing at 0° rotation for all specimens. From biomechanical perspective, fragility sacrum fracture fixation with the new screw-in-screw implant prototype provides higher stability than an SI screw, being able to successfully prevent turn-out. Moreover, it combines the higher stability of transsacral screw fixation with the less risky operational procedure of SI screw fixation and can be considered as their alternative treatment option.

Humeral Shaft Fracture With Placement of an Intramedullary Nail Through an Unrecognized Sarcoma

CASE

A 72-year-old man underwent intramedullary nailing of a humeral diaphysis fracture with passage through an unrecognized pathologic fracture. Four months later, a biopsy of a soft-tissue mass in the arm revealed pleomorphic undifferentiated sarcoma. Only after local recurrence and forequarter amputation was the story of a pathologic fracture through undifferentiated pleomorphic sarcomas of bone clear. The patient developed metastatic disease and died after 2 years postoperatively.

DISCUSSION

Orthopaedic surgeons should consider sarcoma when assessing patients with fractures of unknown etiology and an inappropriate mechanism because the placement of an intramedullary device through a sarcoma of bone has consequences.

Current concept of stress fractures with an additional category of atypical fractures: a perspective review with representative images

Stress fractures have traditionally been classified into three categories: fatigue fractures due to overuse of bone with normal elastic resistance; insufficiency fractures due to everyday physiological stress on fragile bone with poor elastic resistance; and pathologic fractures due to bone weakness involving tumors. The concept of atypical fractures has emerged and is considered a type of stress fracture. However, there has been some inconsistency in interpretation when using the traditional classification of stress fractures, and atypical femoral fractures (AFFs) can potentially be classified into subtypes: "typical" AFFs involving bone turnover suppression due to specific drugs (e.g. bisphosphonates) and fragility fractures of the bowed femoral shaft. In this article, the classification of stress fractures is redefined with the addition of atypical fractures as a fourth category, in which biological activity for fracture healing is absent, to promote consistent understanding and interpretation of clinical conditions involving stress fractures.

Multi-Site Insufficiency Pelvic Fracture Following Total Hip Arthroplasty

Patient: Female, 47-year-old

Final Diagnosis: Pelvic fracture

Symptoms: Hip pain

Medication: —

Clinical Procedure: —

Specialty: Orthopedics and Traumatology

Proximal fibular resection improves knee biomechanics and enhances tibial stress fracture healing in patients with osteoarthritis with varus deformity: a prospective, randomized control analysis

Background

The present study aimed to evaluate the functional outcome of single-stage total knee arthroplasty using long-stem tibial component with proximal fibular resection (PFR) for patients with knee osteoarthritis with varus deformity associated with tibial stress fracture.

Method

A cohort of 62 patients with a mean age 71.63 ± 7.40 years who met the criteria were randomized to a study group and a control group. Patients in the study group underwent single-stage total knee arthroplasty using long-stem tibial component with PFR. The control group received conventional treatment. All patients were followed at 1, 3, 6 and 12 month(s) after surgery. Standard anteroposterior and lateral weight bearing knee X-rays were analyzed. Western Ontario and Mc-master Universities Osteoarthritis Index score (WOMAC) and the visual analog scale (VAS) score were used to assess the functional outcome. The level of significance was set at p < 0.05 levels.

Results

One patient in the study group was lost to follow-up, leaving 61 patients for final assessment. The WOMAC total score and mean VAS score were significantly better in study group than in control group at final follow-up (p < 0.05). All fractures were successfully united in a mean time of 12.26 ± 1.20 weeks in study group. A total of 16 patients in control group had delayed union, five had established nonunion and required further interventions. No complications relating to surgery was detected.

Conclusion

Total knee arthroplasty with PFR for knee arthritis with varus deformity associated with tibial stress fractures restores limb alignment, improves biomechanics, enhances fracture healing and provides excellent functional outcome.

Missing Diagnosis, Pain, and Loss of Function in Older Adults with Rheumatoid Arthritis and Insufficiency Fractures: A Qualitative Study of the Patient's Perspective

Rheumatoid arthritis (RA) is characterised by a chronic, progressive inflammation in the joints and leads to substantial pain, disability, and other morbidities. Few studies document the occurrence of insufficiency fractures, but no studies document the patient's perspective on incurring an insufficiency fracture. The aim of this qualitative study was to explore the patients' perspective on how insufficiency fractures influence their level of activity and to detect their need for rehabilitation. Two focus-group interviews were performed with 10 patients diagnosed with RA and insufficiency fractures. The data from the focus-group interviews were subjected to thematic analysis to provide a sense of the important themes. The 10 patients were all females, aged 57-88 years. Magnetic resonance imaging were performed at a mean of six months and seven days. All patients identified the delayed diagnosis of fracture as a significant burden. They experienced pain but did not receive a diagnosis. When the patients were immobilised, some of them were offered aids such as crutches, which they were unable to use due to their RA. The patients needed a focus on diagnosis and individually customised rehabilitation, taking into account RA and including guidance concerning daily activities, aids, and the regain of physical function.

The effect of stress fracture occurring within the first 12 months of training on subsequent race performance in Thoroughbreds in Hong Kong

BACKGROUND

Racehorses are at an increased risk of stress fracture within the first 12 months of racing and when resuming training after a break. Research in these high-risk periods and on the effect of performance post-recovery is limited.

OBJECTIVES

To describe the occurrence of stress fractures, diagnosed by nuclear scintigraphy (NS), in racehorses' first 12 months training in Hong Kong, and their impact on racing performance and career length.

STUDY DESIGN

Retrospective 1:2 matched case-control study.

METHODS

Clinical records of horses with NS-diagnosed stress fractures within 365 days of import between 2006 and 2018 were collated. Cases and controls were matched on import date. Univariable conditional logistic regression compared signallment, pre-fracture training and post-recovery racing performance between cases and matched controls. Shared Frailty Cox regression analysed time from import to fracture and total career length.

RESULTS

Eighty-seven horses sustained a NS-diagnosed fracture within their first year in Hong Kong (incidence risk 1.7% [95% confidence interval (CI) 1.4%-2.1%; N = 5180]). The humerus (42.0%; 95% CI 31.8%-52.6%; n = 39) and tibia (28.0%; 95% CI 19.1%-38.2%; n = 26) were the most common stress fracture sites. Cases missed a median of 63 days (Interquartile range (IQR) 49-82) of training because of fracture. Within the 12 months following diagnosis, case horses had a median of four (IQR 2-4, P < .0001) fewer race starts and were down HK$ 206 188 (IQR HK$ 0-436 800, P = .007) in race earnings compared to controls. Career length did not significantly differ between cases and controls (median 2 years and 3 months; IQR 15.3-39.1 months; P = .2).

MAIN LIMITATIONS

Only stress fractures diagnosed by NS were included, hence, the study is not representative of all stress fractures occurring in racehorses in Hong Kong.

CONCLUSIONS

Racehorses sustaining a stress fracture within 1 year of entering Hong Kong lost significant time in training, earnings and race starts. However, overall career length was unaffected.

[Radiologic diagnosis of pathologic fractures]

BACKGROUND

Pathologic fractures are fractures that occur without an adequate traumatic event due to focal benign or malignant skeletal lesions. The most common causes of pathologic fractures are cystic bone lesions, plasmocytoma or multiple myeloma, and the development of osseous metastases, which is increasing due to an aging general population and advances in cancer treatment. The differentiation of pathologic fractures from stress fractures, especially osteoporotic insufficiency fractures is crucial for correct treatment planning.

OBJECTIVES

This review intends to explain the imaging characteristics of pathologic fractures. Moreover, it explains the role of imaging when pathologic fractures are suspected. In addition, the Mirels' score and the SINS (Spinal Instability Neoplastic Score), which are powerful yet easy-to-use tools for the assessment of the fracture risk of benign or malignant bony lesions of the extremities and the vertebral column, shall be introduced.

MATERIALS AND METHODS

A PubMed literature search with the following terms was conducted: "pathologic fracture", "fatigue fracture", "insufficiency fracture", "treatment of pathologic fractures", "imaging of pathologic fractures", "fracture risk", "bone metastases", "MRI of pathologic fractures", "CT of pathologic fractures", "differentiation of pathologic and insufficiency fractures", "Mirels' score", "SINS" and "spinal instability neoplastic score".

RESULTS

The definitions of pathologic, fatigue, and insufficiency fractures are explained. Moreover, the role of imaging in the clinical workup of suspected pathologic fractures and the differentiation of pathologic fractures from fatigue or insufficiency fractures as well as common scoring systems to assess the fracture risk of pathologic fractures are described.

Insufficiency fractures of the knee, ankle, and foot in rheumatoid arthritis: A case series and case-control study

OBJECTIVE

To evaluate cases of insufficiency fractures verified by magnetic resonance imaging (MRI) of the knee, ankle, and foot in patients with rheumatoid arthritis (RA) cared for in our clinic over an 8-year period, to identify possible risk factors, and to test these in a case-control study.

METHODS

All patients in the rheumatology clinic with RA were registered prospectively in the database, DANBIO. All MRIs ordered from the clinic were registered and coded according to the anatomical region. We were thus able to retrieve all patients with RA and performed an MRI of the knee or ankle/foot. The patients with fractures constituted the case series, and the patients without fractures constituted the control group.

RESULTS

The RA clinic population comprised 1,624 patients who underwent a total of 70 MRIs.

CASE SERIES

39 insufficiency fractures were identified in 32 patients; 93% were women, and the median age was 68 years (range 33-89 years). Half of the patients had a T score >-2.5. The case control group without fractures comprised 38 patients; 74% were women, and the median age was 62 years (range 32-84 years). In the case series, 20 patients experienced later additional episodes of insufficiency fractures in the knee, ankle, or foot.

CONCLUSION

Insufficiency fractures of the knee, ankle, and foot are a significant cause of pain and long-lasting disability in RA. Recurrent fractures are common. Diagnosis is often delayed and confused with arthritic activity. Conventional radiography and DEXA scan are often normal. Older age, female gender, radiological erosions in hand/wrist, and treatment with methotrexate were all significantly associated with fractures.

A Rare Case of Patella Fracture in Osteopetrosis: A Case Report

CASE

Fractures in patients with osteopetrosis pose unique technical challenges to the orthopaedic surgeon. We present a case of a 43-year-old man with osteopetrosis who underwent tension band wiring of a patella fracture. The intraoperative appearance of osteopetrotic bone, technical difficulties in passing wires through dense bone, and how this was overcome are presented.

CONCLUSIONS

A simple transverse fracture of the patella in a patient with osteopetrosis can be fixed successfully using a standard tension band construct.

Etiology of Lumbosacral Radiculoplexopathy: Sacral Insufficiency Fracture on Magnetic Resonance Imaging

BACKGROUND

Sacral insufficiency fracture (SIF) can cause lumbosacral radiculoplexopathy (LSRP) and is probably under-recognized. Symptoms may include nonspecific lumbar spine or buttock pain that is exacerbated by physical activity and alleviated with rest. The frequency of LSRP secondary to SIF has not been reported.

QUESTIONS/PURPOSES

We aimed to determine the frequency of LSRP associated with SIF using magnetic resonance imaging (MRI) of the lumbar spine.

METHODS

We searched a radiology database at our institution using the keywords "sacral insufficiency fracture" and "lumbar spine MRI" for patient records from January 2014 through December 2017. We assessed for the presence of LSRP, reflected by elevated T2-weighted or short tau inversion recovery (STIR) signal intensity and enlargement of the nerve on noncontrast lumbar spine MRI. An incompletely healed vertically oriented SIF was confirmed if there was a persistent bone marrow edema pattern adjacent to the fracture site; we did not include purely transverse SIFs. The final cohort comprised 57 patients (48 female; age range, 14 to 89 years).

RESULTS

Abnormalities of the extraforaminal L5 nerve root or the combined L4 and L5 nerve roots (the lumbosacral trunk) were identified in 19 (33%) of 57 patients, with a total of 23 sites (bilateral involvement in four cases). Of the 23 abnormal nerves, 19 (82.6%) had corresponding, clinically documented radicular symptoms and 16 (69.6%) had no other explanation on MRI for their radicular symptoms other than SIF.

CONCLUSIONS

LSRP caused by SIF is an entity all radiologists should be cognizant of, especially in cases of otherwise unexplained radicular symptoms. The diagnosis of SIF can be helpful in cases involving concomitant multilevel lumbar spondylosis and neural foraminal stenosis.

Early detected femoral neck insufficiency fracture in a patient treated with long-term bisphosphonate therapy for osteoporosis: A need for MRI

•

If long term bisphosphonate users complain of non-traumatic hip pain, medical examination should be taken with care.

•

Even though no fractures are identified in their radiographs, it is recommended to check an MRI.

•

If the fracture can be identified before cortical breakage, the treatment success rate for the fracture will be high.

Introduction

Atypical femoral fracture is an uncommon complication of prolonged use of bisphosphonates, mainly occurring in the femoral shaft. We report a case of an atraumatic insufficiency fracture of femoral neck after four years of treatment with a bisphosphonate.

Presentation of case

A 71-year-old female presented with history of pain on Lt. hip and difficulty in walking. Although there was no fracture on the radiographs, diagnosis could be made early using magnetic resonance imaging (MRI) scans. She was treated by internal fixation using cannulated screws.

Discussion

Because bisphosphonate prevents bone healing and remodeling, it is difficult to accomplish the bony union despite of proper treatment in patients who have fractured after long-term use of bisphosphonate.

Conclusion

A high suspicion index and early diagnosis through the use of MRI are essential for the successful treatment of these fractures.

Isolated Distal Fibular Stress Fracture after Total Hip Arthroplasty in a Patient with Developmental Dysplasia of the Hip

Stress fractures following total hip arthroplasty in the lower limbs away from the surgical area are very rare. We report a case of stress fracture in the isolated distal fibula that presented five months after total hip arthroplasty in a patient with developmental dysplasia of the hip. A 67-year-old woman diagnosed with coxarthrosis of the right hip joint, classified as Crowe's group 3, underwent total hip arthroplasty with acetabular reconstruction using a bulk bone graft. The surgery successfully treated the preoperative leg length discrepancy and flexion and external rotation contractures. The alignment of the right lower limbs changed from slight varus to valgus knee following surgery. The postoperative process went well; however, she experienced lateral ankle pain on the affected side five months after surgery. No obvious fracture was observed via radiograph; however, she received a subsequent diagnosis of isolated distal fibula stress fracture. Additionally, she was diagnosed with vitamin D deficiency. Valgus alignment change of the knee joint and vitamin D deficiency were considered the main causes of the stress fracture. Stress fractures should be suspected in patients complaining of unexpected pain following total hip arthroplasty, even in distant areas of the affected limb, especially in osteoporotic patients.

Acute atraumatic bilateral acetabular insufficiency fractures

Bilateral acetabular fractures have been documented in the setting of high-energy trauma, but few reports regarding atraumatic bilateral acetabular fractures exist. The following is a case report of bilateral insufficiency acetabular fractures which occurred acutely in the absence of trauma in a 49-year-old female. The case highlights the importance of perioperative awareness of those patients at significant risk of insufficiency fractures and offers a relatively elegant, less invasive solution for early mobilization in the context of acetabula insufficiency fractures.

Successful treatment for bilateral femoral neck insufficiency fractures: a rare lesion case report and an updated review of the literature

BACKGROUND

The incidence of insufficiency fracture (IF) at femoral neck is low, accounting for about 5% of all insufficiency fractures, and IF at bilateral femoral neck is less common with more occurrence in athlete or serviceman. With the aging of populations, more cases of bilateral femoral neck IF have occurred recently, while the standard clinical treatment still remains lacking due to the complexity of these patients.

CASE PRESENTATION

A 55-year-old male patient complained pain in his bilateral hip, with no history of trauma, glucocorticoid hormone consumption or radiotherapy, and imaging examination revealed fracture nonunion and shortening in his left femoral neck, and double fracture line on the right femoral neck. The patient received a cementless THA for the left femoral neck fracture and conservative treatment for the right side, followed by Elcatonin injection and oral administration of Carbonate D3 Granules. After 4 months of fellow-up, the patient presented improved functional scorings in bilateral hip joints, with no signs of prothesis infection or loosening.

CONCLUSION

We present a rare case of bilateral femoral neck IF in a middle-aged male and the treatment is successful. The timely CT and MRI examinations of bilateral hip joints for patients was necessary for orthopedists to select proper therapeutic regimen. In addition, the choice for therapeutic regimen of bilateral femoral IF should not only be based on the professional judgement of orthopedists, but also on the wishes of patients.

Calcaneal insufficiency fractures following total knee arthroplasty: Classification and clinical findings

BACKGROUND

Calcaneal insufficiency fracture (IF) following total knee arthroplasty (TKA) is a rare disorder. This study aimed to examine the prevalence and clinical findings of calcaneal IF following TKA.

METHODS

We retrospectively reviewed 3,585 consecutive patients undergoing primary TKA between 2012 and 2017 in four hospitals. Calcaneal IF following TKA was diagnosed by plain radiography or magnetic resonance imaging. First, we investigated the prevalence and clinical findings of calcaneal IF following TKA. Second, we classified calcaneal IF into three types based on its location: type 1, fracture by traction force around the Achilles tendon insertion; type 2, compression fracture around the posterior subtalar joint; and type 3, fracture by ground reaction force at the bottom of the calcaneus. Finally, we compared the clinical findings between calcaneal IF with and without TKA.

RESULTS

Calcaneal IF following TKA was seen in 17 (0.5%) of the 3,585 patients undergoing primary TKA. All patients were female, with a mean age of 76.5 ± 5.9 years, relatively high body mass index (BMI), and osteoporosis. All fractures achieved bone union with conservative treatment. Type 1 fractures were the most common. Calcaneal IFs following TKA were significantly shorter in height and the patients had higher BMI than those without TKA. The locations of calcaneal IF following TKA varied, while only type 1 calcaneal IFs were seen in cases without TKA. However, there were no significant differences with regard to the bone union period or malunion between the two groups.

CONCLUSIONS

Calcaneal IF should be suspected in patients presenting with ipsilateral foot pain following TKA, particularly in female patients with a relatively high BMI and osteoporosis. Calcaneal IF can be classified into three types based on the fracture location. These variations in calcaneal IF may be due to differences in conditions and changes in mechanical loading of the lower extremity and bone quality following TKA.

Potential bone fragility of mid-shaft atypical femoral fracture: Biomechanical analysis by a CT-based nonlinear finite element method

INTRODUCTION

The authors previously reported a CT-based nonlinear finite element analysis (nonlinear CT/FEA) model to investigate loading stress distribution in the femoral shaft of patients with atypical femoral fractures (AFFs). This showed that stress distribution, influenced primarily by femoral bowing, may determine the location of AFF. Here, we demonstrate the locational characteristics associated with AFFs in an Asian, specifically Japanese, population regarding bone strength. This is the second report from our multicentre research project suggesting a possible new concept of diagnostic criteria or treatment according to AFF subtype.

PATIENTS AND METHODS

A multicentre prospective study was conducted at 12 hospitals in Japan from August 2015 through June 2018. We recruited three study groups composed of elderly females over the age of 60 years-the mid-shaft AFF group (n = 14; 80.0 ± 6.5 years), the subtrochanteric AFF group (n = 15; 73.9 ± 6.8 years), and the control group who had sustained unilateral hip fracture (n = 21; 82.1 ± 7.1 years)-and analysed femoral neck bone density and strength. Bone strength of the femoral neck was predicted with an evaluation method using nonlinear CT/FEA in both standing and falling configuration.

RESULTS

Femoral neck bone density and strength were significantly higher in the subtrochanteric AFF group compared with the mid-shaft AFF and control groups (p <  0.0001). No significant difference was seen in bone strength between the mid-shaft AFF and control groups (standing, p =  0.7616; falling, p =  0.3803).

CONCLUSIONS

AFF has different features, in terms of bone strength, depending on fracture location. At the very least, Japanese patients with mid-shaft AFF could be at high risk of hip fracture because of bone fragility, in contrast to the firm bone of subtrochanteric AFF. For internal fixation of mid-shaft AFF using an IM nail, cervical screw insertion toward the femoral head might be recommended to prevent possible hip fracture.

Imaging Features and Management of Stress, Atypical, and Pathologic Fractures

Traumatic and atraumatic fractures are entities with distinct but often overlapping clinical manifestations, imaging findings, and management protocols. This article is a review of terminology, etiology, and key imaging features that affect management of atraumatic fractures including stress fractures, atypical femoral fractures, and pathologic fractures. The terminology of atraumatic fractures is reviewed, with an emphasis on the distinctions and similarities of stress, atypical, and pathologic fractures. The basic biomechanics of normal bone is described, with an emphasis on the bone remodeling pathway. This framework is used to better convey the shared etiologies, key differences, and important imaging findings of these types of fractures. Next, the characteristic imaging findings of this diverse family of fractures is discussed. For each type of fracture, the most clinically relevant imaging features that guide management by the multidisciplinary treatment team, including orthopedic surgeons, are reviewed. In addition, imaging features are reviewed to help discriminate stress fractures from pathologic fractures in patients with challenging cases. Finally, imaging criteria to risk stratify an impending pathologic fracture at the site of an osseous neoplasm are discussed. Special attention is paid to fractures occurring in the proximal femur because the osseous macrostructure and mix of trabecular and cortical bone of the proximal femur can function as a convenient framework to understanding atraumatic fractures throughout the skeleton. Atraumatic fractures elsewhere in the body also are used to illustrate key imaging features and treatment concepts. ^©RSNA, 2018.

Nomenclature of Subchondral Nonneoplastic Bone Lesions

OBJECTIVE. The purpose of this article is to summarize the nomenclature of nonneoplastic conditions affecting subchondral bone through a review of the medical literature and expert opinion of the Society of Skeletal Radiology Subchondral Bone Nomenclature Committee. CONCLUSION. This consensus statement summarizes current understanding of the pathophysiologic characteristics and imaging findings of subchondral nonneoplastic bone lesions and proposes nomenclature to improve effective communication across clinical specialties and help avoid diagnostic errors that could affect patient care.

Additional Sacroplasty Does Not Improve Clinical Outcome in Minimally Invasive Navigation-Assisted Screw Fixation Procedures for Nondisplaced Insufficiency Fractures of the Sacrum

STUDY DESIGN

Prospective single-center cohort study (noninferiority study).

OBJECTIVE

To compare clinical results of navigation-assisted screw fixation (NSF) to those of NSF with additional sacroplasty (NSF + SP) for immobilizing nondisplaced insufficiency fractures of the sacrum.

SUMMARY OF BACKGROUND DATA

NSF for sacral insufficiency fractures is a new, technically demanding procedure requiring surgical skills and experience. Up to date, controversies exist about the benefit of additional sacroplasty in surgically stabilized insufficiency fractures of the sacrum.

METHODS

From February 2011 to May 2017, all individuals with immobilizing nondisplaced sacral insufficiency fractures surgically treated using 3D-fluoroscopy for 3D-real-time navigation and postinstrumentation screw control in the form of NSF (I) or NSF + SP (II) were enrolled. SP was performed only in absence of transforaminal or central fractures. Outcome parameters were postsurgical pain relief determined by visual analog scale, postsurgical improvement of disability evaluated using the Oswestry Disability Index, and length of postsurgical hospital stay.

RESULTS

In 2 groups of 26 individuals, each, a total of 124 insufficiency fractures of sacral vertebrae were surgically treated. Postoperative pain-level decrease was comparable in both groups (5.3 vs. 5.4 visual analog scale points). Extent of postoperative disability score improvement (53.4 vs. 57.7 Oswestry Disability Index points) led to successful remobilization after similar durations of postsurgical hospital stay (9.3 vs. 9.6 days). Minimum clinically important differences of outcome parameters were not reached in the comparison of study group results. In procedures with SP, no major complications occurred, in those without SP, no specific complications were observed.

CONCLUSION

This comparative study indicates noninferiority of NSF compared to NSF + SP for sacral insufficiency fractures, and could not confirm clinical advantages of additional SP concerning pain relief, improvement of fracture-related disability, or time from surgery to discharge. Therefore, additional sacroplasty is not recommended to enhance the clinical benefit for patients receiving image-guided sacral screw fixation.

LEVEL OF EVIDENCE

2.

Regular physical exercise before entering military service may protect young adult men from fatigue fractures

BACKGROUND

Bone stress fractures are overuse injuries commonly encountered in sports and military medicine. Some fatigue fractures lead to morbidity and loss of active, physically-demanding training days. We evaluated the incidence, anatomical location, risk factors, and preventive measures for fatigue fractures in young Finnish male conscripts.

METHODS

Five cohorts of 1000 men performing military service, classified according to birth year (1969, 1974, 1979, 1984, 1989), were analysed. Each conscript was followed for his full military service period (180 days for conscripts with rank and file duties, 270 days for those with special training, 362 days for officers and highly trained conscripts). Data, including physical activity level, were collected from a standard pre-information questionnaire and from the garrisons' healthcare centre medical reports. Risk factor analysis included the conscripts' service class (A, B), length of military service, age, height, weight, body mass index, smoking, education, previous diseases, injuries, and subjective symptoms, as well as self-reports of physical activity before entering the service using a standard military questionnaire.

RESULTS

Fatigue fractures occurred in 44 (1.1%) of 4029 men, with an incidence of 1.27 (95% confidence interval: 0.92-1.70) per 1000 follow-up months, and mostly (33/44, 75%) occurred at the tibial shaft or metatarsals. Three patients experienced two simultaneous stress fractures in different bones. Most fatigue fractures occurred in the first 3 months of military service. Conscripts with fatigue fractures lost a total of 1359 (range 10-77) active military training days due to exemptions from duty. Conscripts reporting regular (> 2 times/week) physical activity before entering the military had significantly fewer (p = 0.017) fatigue fractures. Regular physical activity before entering the service was the only strong explanatory, protective factor in the model [IRR = 0.41 (95% CI: 0.20 to 0.85)]. The other measured parameters did not contribute significantly to the incidence of stress fractures.

CONCLUSION

Regular and recurrent high-intensity physical activity before entering military service seems to be an important preventive measure against developing fatigue fractures. Fatigue fractures should be considered in conscripts seeking medical advice for complaints of musculoskeletal pain, and taken into consideration in planning military and other physical training programs.

Biomechanical analysis of supra-acetabular insufficiency fracture using finite element analysis

BACKGROUND

Supra-acetabular insufficiency fractures (SAIFs) occur in the upper acetabulum and are rare compared with insufficiency sacral, femoral head, or ischial fractures. However, SAIFs are known to occur in low grade trauma, and the underlying mechanism is still remained unclear.

METHODS

We performed biomechanical analysis using finite element analysis to clarify the mechanisms underlying the development of SAIFs. Patient-specific models and bone mineral density (BMD) were derived from pelvic computed tomography data from two patients with SAIF (unaffected side) and two healthy young adults. The bone was assumed to be an isotropic, linearly elastic body. We assigned Young's modulus of each element to the pelvis based on the BMD, and reported the relationships for BMD-modulus. Clinically relevant loading conditions-walking and climbing stairs-were applied to the models. We compared the region of failure risk in each acetabulum using a maximum principal strain criterion.

RESULTS

The average supra-acetabular BMD was less than that of the hemi-pelvis and femoral head, but was higher than that of the femoral neck and greater trochanter. Greater minimum principal strain was concentrated in the supra-acetabular portion in both the SAIF and healthy models. In the SAIF models, the higher region of the failure risk matched the fracture site on the acetabulum.

CONCLUSIONS

Relative fragility causes compressive strain to concentrate in the upper acetabulum when walking and climbing stairs. When presented with a patient complaining of hip pain without apparent trauma or abnormal X-ray findings, physicians should consider the possibility of SAIF and perform magnetic resonance imaging for the diagnosis of SAIF.

Biomechanical investigation of four different fixation techniques in sacrum Denis type II fracture with low bone mineral density

With increasing life expectancy, fragility fractures of the pelvic ring are seen more frequently. Although their osteosynthesis can be very challenging, specific biomechanical studies for investigation of the fixation stability are still lacking. The aim of this study was to biomechanically evaluate four different fixation methods for sacrum Denis type II fractures in osteoporotic bone. Unstable Denis type II vertical sacrum fractures were created in 16 human pelves. Their osteosynthesis was performed with one sacro-iliac screw, posterior sacral plating, triangular fixation, or spino-pelvic fixation. For that purpose, each pelvis was randomly assigned to two paired groups for treatment with either SI-screw/posterior sacral plating or triangular fixation/spino-pelvic fixation. Each hemi-pelvis was cyclically tested under progressively increasing axial compression. Relative interfragmentary movements were investigated via optical motion tracking analysis. Axial stiffness of triangular fixation was significantly higher versus posterior sacral plating and spino-pelvic fixation (p ≤ 0.022), but not significantly different in comparison to SI-screw fixation (p = 0.337). Cycles to 2, 3, 5, and 8 mm fracture displacement, as well as to 3°, 5°, and 8° gap angle at the fracture site were significantly higher for triangular fixation compared to all other groups (p ≤ 0.041). Main failure mode for all osteosynthesis techniques was screw cutting through the bone, leading loss of fixation stability. From a biomechanical point of view, triangular fixation in sacrum Denis type II fractures demonstrated less interfragmentary movements and should be considered in unstable fragility fractures of the sacrum. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1624-1629, 2018.

Pharmacological interventions for the prevention of insufficiency fractures and avascular necrosis associated with pelvic radiotherapy in adults

BACKGROUND

Pelvic radiotherapy is a treatment delivered to an estimated 150,000 to 300,000 people annually across high-income countries. Fractures due to normal stresses on weakened bone due to radiotherapy are termed insufficiency fractures. Pelvic radiotherapy-related interruption of the blood supply to the hip is termed avascular necrosis and is another recognised complication. The reported incidences of insufficiency fractures are 2.7% to 89% and risk of developing avascular necrosis is 0.5%. These complications lead to significant morbidity in terms of pain, immobility and consequently risk of infections, pressure sores and mortality.

OBJECTIVES

To assess the effects of pharmacological interventions for preventing insufficiency fractures and avascular necrosis in adults over 18 years of age undergoing pelvic radiotherapy.

SEARCH METHODS

We performed electronic literature searches in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase and DARE to 19 April 2017. We also searched trial registries. Further relevant studies were identified through handsearching of citation lists of included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or non RCTs with concurrent comparison groups including quasi-RCTs, cluster RCTs, prospective cohort studies and case series of 30 or more participants were screened. We included studies assessing the effect of pharmacological interventions in adults over 18 years of age undergoing radical pelvic radiotherapy as part of anticancer treatment for a primary pelvic malignancy. We excluded studies involving radiotherapy for bone metastases. We assessed use of pharmacological interventions at any stage before or during pelvic radiotherapy. Interventions included calcium or vitamin D (or both) supplementation, bisphosphonates, selective oestrogen receptor modulators, hormone replacement therapy (oestrogen or testosterone), denosumab and calcitonin.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors to obtain missing data. Data were to be pooled using the random-effects model if study comparisons were similar, otherwise results were to be reported narratively.

MAIN RESULTS

We included two RCTs (1167 participants). The first RCT compared zoledronic acid with placebo in 96 men undergoing pelvic radiotherapy for non-metastatic prostate cancer.The second RCT had four treatment arms, two of which evaluated zoledronic acid plus adjuvant androgen suppression compared with androgen suppression only in 1071 men undergoing pelvic radiotherapy for non-metastatic prostate cancer.Both studies were at a moderate to high risk of bias and all evidence was judged to be of very low certainty.The studies provided no evidence on the primary outcomes of the review and provided limited data in relation to secondary outcomes, such that meta-analyses were not possible. Both studies focused on interventions to improve bone health in relation to androgen deprivation rather than radiation-related insufficiency fractures and avascular necrosis. Few fractures were described in each study and those described were not specific to insufficiency fractures secondary to radiotherapy. Both studies reported that zoledronic acid in addition to androgen deprivation and pelvic radiotherapy led to improvements in BMD; however, the changes in BMD were measured and reported differently. There was no available evidence regarding adverse effects.

AUTHORS' CONCLUSIONS

The evidence relating to interventions to prevent insufficiency fractures and avascular necrosis associated with pelvic radiotherapy in adults is of very low certainty. This review highlights the need for prospective clinical trials using interventions prior to and during radiotherapy to prevent radiation-related bone morbidity, insufficiency fractures and avascular necrosis. Future trials could involve prospective assessment of bone health including BMD and bone turnover markers prior to pelvic radiotherapy. The interventions for investigation could begin as radiotherapy commences and remain ongoing for 12 to 24 months. Bone turnover markers and BMD could be used as surrogate markers for bone health in addition to radiographic imaging to report on presence of insufficiency fractures and development of avascular necrosis. Clinical assessments and patient reported outcomes would help to identify any associated adverse effects of treatment and quality of life outcomes.

Sacroiliitis and sacral insufficiency fracture: A rare coexistence

Sacral insufficiency fracture (SIF) is an uncommon cause of hip and back pain. Sacroiliitis, often a feature of inflammatory conditions of spinal column, is inflammation of sacroiliac joints. Herein, we report a 41-year-old woman presenting with a SIF and sacroiliitis as a part of non-radiographic axial spondyloarthritis.

3D bone texture analysis as a potential predictor of radiation-induced insufficiency fractures

Background

The aim of our work is to assess the potential role of texture analysis (TA), applied to computed tomography (CT) simulation scans, in relation to the development of insufficiency fractures (IFs) in patients undergoing radiation therapy (RT) for pelvic malignancies.

Methods

We analyzed patients undergoing pelvic RT from Jan-2010 to Dec-2016, 31 of whom had developed IFs of the pelvis. We analyzed CT simulation scans using LifeX Software^©, and in particular we selected three regions of interest (ROI): L5 body, the sacrum and both the femoral heads. The ROI were automatically contoured using the treatment planning software Raystation^©. TA parameters included parameters from the gray-level histogram, indices from sphericity and from the matrix of GLCM (gray level co-occurrence matrix). The IFs patients were matched (1:1 ratio) with control patients who had not developed IFs, and were matched for age, sex, type of tumor, menopausal status, RT dose and use of chemotherapy. Univariate and multivariate analyses (logistic regression) were used for statistical analysis.

Results

Significant TA parameters on univariate analysis included both parameters from the histogram distribution, as well from the matrix of GLCM. On logistic regression analysis the significant parameters were L5-energy [P=0.033, odds ratio (OR): 1.997, 95% CI: 1.059-3.767] and FH-Skewness (P=0.014, OR: 2.338, 95% CI: 1.191-4.591), with a R2: 0.268. A ROC curve was generated from the binary logistic regression, and the AUC was 0.741 (95% CI: 0.627-0.855, P=0.001, S.E.: 0.058).

Conclusions

In our experience, 3D-bone CT TA can be used to stratify the risk of the patients to develop radiation-induced IFs. A prospective study will be conducted to validate these findings.

Insufficiency Fractures of the Distal Tibia and Fibula Following Total Hip Arthroplasty: A Case Report

Introduction:

Although periprosthetic fractures of the femur have been well documented, insufficiency fractures following total hip arthroplasty (THA) have been rarely described. We report a case of an insufficiency fracture in the distal tibia and fibula that occurred after THA.

Case Report:

A 54-year-old woman presented with severe pain in the bilateral hip joints and was diagnosed with end-stage osteoarthritis. She underwent THA on the right side. Although the postoperative course was uneventful, she suddenly experienced severe pain and swelling in the right leg without any history of trauma 22 weeks after the surgery. She was first diagnosed with cellulitis by her local doctor and was treated with oral antibiotics. Her symptoms persisted, and she returned to our hospital 1 month later. Her right distal leg and ankle were diffusely swollen and tender. Plain radiographs revealed a sclerotic linear zone in the distal tibia and fibula. She was diagnosed with insufficiency fractures in the distal tibia and fibula following THA. Local disuse osteoporosis and increased mechanical stress after THA as a result of pain relief could be the causes for her fracture. Her right leg and ankle were immobilized with a splint for another 4 weeks. Her symptoms subsided gradually, and fracture union was confirmed on the follow-up X-ray.

Conclusion:

Insufficiency fractures should be suspected in patients complaining of unexplainable pain, even in the distant area of the affected limb, for at least 6 months following THA

Understanding Bone Strength Is Not Enough

Increases in fracture risk beyond what are expected from bone mineral density (BMD) are often attributed to poor "bone quality," such as impaired bone tissue strength. Recent studies, however, have highlighted the importance of tissue material properties other than strength, such as fracture toughness. Here we review the concepts behind failure properties other than strength and the physical mechanisms through which they cause mechanical failure: strength describes failure from a single overload; fracture toughness describes failure from a modest load combined with a preexisting flaw or damage; and fatigue strength describes failure from thousands to millions of cycles of small loads. In bone, these distinct failure mechanisms appear to be more common in some clinical fractures than others. For example, wrist fractures are usually the result of a single overload, the failure mechanism dominated by bone strength, whereas spinal fractures are rarely the result of a single overload, implicating multiple loading cycles and increased importance of fatigue strength. The combination of tissue material properties and failure mechanisms that lead to fracture represent distinct mechanistic pathways, analogous to molecular pathways used to describe cell signaling. Understanding these distinct mechanistic pathways is necessary because some characteristics of bone tissue can increase fracture risk by impairing fracture toughness or fatigue strength without impairing bone tissue strength. Additionally, mechanistic pathways to failure associated with fracture toughness and fatigue involve multiple loading events over time, raising the possibility that a developing fracture could be detected and interrupted before overt failure of a bone. Over the past two decades there have been substantial advancements in fracture prevention by understanding bone strength and fractures caused by a single load, but if we are to improve fracture risk prevention beyond what is possible now, we must consider material properties other than strength. © 2017 American Society for Bone and Mineral Research.