No link between fracture risk and use of vitamin A-related substances

Vestergaard and colleagues analyze data from a nationwide Danish registry for 124,655 patients who sustained fractures in the year 2000 and 373,962 age- and sex-matched individuals.

Their goal is to arrive at the incidence of fractures in those exposed to systemic vitamin A analogues vs. who those not exposed to these substances.

The researchers control their investigation for possibly confounding factors, such as social variables, contact with hospitals and care providers, alcoholism and any factors known to possibly affect fracture risk, such as use of corticosteroids and anti-epileptic medications.

When Vestergaard and colleagues match one fracture patient each with three controls, they find that neither topical nor systemic vitamin A analogues are associated with the change in fracture risk at any skeletal site.

Furthermore, even large daily doses —14 mg — of vitamin A analogues are not associated with an increased risk of fracture, nor was acne or psoriasis medication.

Reference

Vestergaard P, Rejnmark L and Mosekilde L. High-dose treatment with vitamin A analogues and risk of fractures.Arch Dermatol. 2010;146(5):478-482.

Alendronate reduces the excretion of risk factors for calcium phosphate stone formation in postmenopausal women with osteoporosis.

Potential approach with BPs may be associated with thiazide diuretics or indapamide in the management of post-menopausal women with HC and associated bone loss.

Studies on the larger sample size are needed to demonstrate the efficacy on the fracture outcome.

ALN not only improves BMD and osteoporosis, but also reduces the risk of calcium phosphate stone formation in postmenopausal women.

Researchers identify protein involved in causing osteoporosis, arthritis

First paper to identify that IRF-8 is a novel key inhibitory factor in osteoclastogenesis.

Downregulation of IRF-8 increases the production of cells called osteoclasts that are responsible for breaking down bone.

Enhanced development of osteoclasts can create canals and cavities that are hallmarks of diseases such as periodontitis, osteoporosis and rheumatoid arthritis.

Bilateral femoral neck fractures due to transient osteoporosis of pregnancy

Figure 1. Antero-posterior radiograph of the pelvis post partum.

Figure 1. Antero-posterior radiograph of the pelvis post partum.

Figure 2. T1 weighted coronal MRI scan of the pelvis post partum.

Figure 2. T1 weighted coronal MRI scan of the pelvis post partum.

Figure 3. Antero-posterior radiograph of the pelvis post fixation with dynamic hip screws.

Figure 3. Antero-posterior radiograph of the pelvis post fixation with dynamic hip screws.

Transient osteoporosis of pregnancy (TOP)

Transient osteoporosis of pregnancy (TOP) is a rare, idiopathic self-limiting condition typically associated with the third trimester of pregnancy.

It almost always affects a single hip although bilateral presentation and involvement of the knee have been reported [1-3].

TOP usually presents with a sudden, quite severe onset of unilateral groin pain with no history of trauma.

The patient may be unable to walk, or may have an antalgic gait.

Pain is elicited by hip rotation, although a full range of motion is common.

Radiographs are avoided in pregnancy where possible, and are a poor investigation for demonstrating early osteopaenia.

Magnetic Resonance Imaging (MRI) reveals low signal intensity of bone marrow on T1 weighted images, and high signal on T2 weighted images suggestive of bone marrow oedema[4].

The natural history is of resolution of symptoms over the course of 3 to 6 months

Hip fracture secondary to TOP

Hip fracture secondary to TOP is very rare with only 12 reported patients in the literature to date; in two cases the hip fractures were bilateral[2,3,5-8].

The majority of these fractures were caused by a traumatic event.

Atraumatic hip fractures secondary to TOP are even more unusual and are easily overlooked and hence may present to the orthopaedic surgeon at a late stage, making management more challenging.

Musculoskeletal complaints are very common in pregnancy.

The position and weight of the gravid uterus alters the centre of gravity and loading patterns of the axial and appendicular skeleton, whilst hormonal changes lead to joint laxity, and fluid retention may cause neural compression[9].

The majority of musculoskeletal complaints are not serious, and are managed conservatively without a specific diagnosis.

Pregnant women frequently complain of hip or pelvic pain.

The differential diagnosis includes some serious problems that need to be excluded, namely

1. transient osteoporosis,
2. osteonecrosis and
3. pubic symphysiolysis.

Conventionally ionising radiation is avoided during pregnancy although Brodell et al. suggested that in the third trimester of pregnancy the benefits of adequate investigation of hip pain may outweigh the minimal risks[5].

MRI during pregnancy

There is no conclusive evidence that MRI has deleterious effects, however the safety of MRI has yet to be definitively proven[10].

It is in common use in the third trimester of pregnancy where clinically indicated[11] and is generally considered to be safe[12].

MRI has a high sensitivity for diagnosis of occult hip fracture[13] and can reliably distinguish between osteonecrosis and transient osteoporosis[4], making it the investigation of choice for hip pain in the third trimester of pregnancy.

Displaced intracapsular fractures have a high incidence of non-union and avascular necrosis[14].

It has however been shown that the risk of non-union is independent of bone quality[15] therefore in young patients with high value hips internal fixation should be the goal.

References

1.	Lloyd JM, Lewis M, Jones A: Transient osteoporosis of the knee in pregnancy. J Knee Surg 2006, 19:121–123. [PubMed]
2.	Aynaci O, Kerimoglu S, Ozturk C, Saracoglu M: Bilateral non-traumatic acetabular and femoral neck fractures due to pregnancy-associated osteoporosis. Arch Orthop Trauma Surg 2008, 128:313–316. [PubMed] [CrossRef]
3.	Munker R, Niedhart C, Niethard FU, Schmidt-Rohlfing B: [Bilateral fracture of the femoral neck following transient osteoporosis in pregnancy]. Z Orthop Ihre Grenzgeb 2007, 145:88–90. [PubMed] [CrossRef]
4.	Takatori Y, Kokubo T, Ninomiya S, Nakamura T, Okutsu I, Kamogawa M: Transient osteoporosis of the hip. Magnetic resonance imaging. Clin Orthop Relat Res 1991, :190–194. [PubMed]
5.	Brodell JD, Burns JE, Heiple KG: Transient osteoporosis of the hip of pregnancy. Two cases complicated by pathological fracture. J Bone Joint Surg Am 1989, 71:1252–1257. [PubMed]
6.	Cohen I, Melamed E, Lipkin A, Robinson D: Transient osteoporosis of pregnancy complicated by a pathologic subcapital hip fracture. J Trauma 2007, 62:1281–1283. [PubMed]
7.	Fokter SK, Vengust V: Displaced subcapital fracture of the hip in transient osteoporosis of pregnancy. A case report. Int Orthop 1997, 21:201–203. [PubMed] [CrossRef]
8.	Wood ML, Larson CM, Dahners LE: Late presentation of a displaced subcapital fracture of the hip in transient osteoporosis of pregnancy. J Orthop Trauma 2003, 17:582–584. [PubMed] [CrossRef]
9.	Smith MW, Marcus PS, Wurtz LD: Orthopedic issues in pregnancy. Obstet Gynecol Surv 2008, 63:103–111. [PubMed] [CrossRef]
10.	Nagayama M, Watanabe Y, Okumura A, Amoh Y, Nakashita S, Dodo Y: Fast MR imaging in obstetrics. Radiographics 2002, 22:563–580. [PubMed]
11.	De Wilde JP, Rivers AW, Price DL: A review of the current use of magnetic resonance imaging in pregnancy and safety implications for the fetus. Prog Biophys Mol Biol 2005, 87:335–353. [PubMed] [CrossRef]
12.	Garcia-Bournissen F, Shrim A, Koren G: Safety of gadolinium during pregnancy. Can Fam Physician 2006, 52:309–310. [PubMed]
13.	Lubovsky O, Liebergall M, Mattan Y, Weil Y, Mosheiff R: Early diagnosis of occult hip fractures MRI versus CT scan. Injury 2005, 36:788–792. [PubMed] [CrossRef]
14.	Lu-Yao GL, Keller RB, Littenberg B, Wennberg JE: Outcomes after displaced fractures of the femoral neck. A meta-analysis of one hundred and six published reports. J Bone Joint Surg Am 1994, 76:15–25. [PubMed]
15.	Heetveld MJ, Raaymakers EL, van Eck-Smit BL, van Walsum AD, Luitse JS: Internal fixation for displaced fractures of the femoral neck. Does bone density affect clinical outcome? J Bone Joint Surg Br 2005, 87:367–373. [PubMed] [CrossRef]