Journal of Orthopaedic Surgery 2012;20(2):260-2
Bilateral subcapital femoral neck fractures secondary to transient osteoporosis during pregnancy: a case report Mohammad Jafar Emami, Hamid Reza Abdollahpour, Ali Reza Kazemi, Amir Reza Vosoughi
Research Center for Bone & Joint Diseases, Department of Orthopedic Surgery, Chamran Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
ABSTRACT Transient osteoporosis during pregnancy is a rare, self-limiting disease. We report on a 36-year-old woman who had bilateral subcapital femoral neck fractures during the 6th month of pregnancy. The diagnosis was made 4 days after delivery, because radiography was declined by the patient for fear of radiation. Fixation was not feasible owing to bone resorption, and 2-stage bipolar hemiarthroplasty was therefore performed. Magnetic resonance imaging is the best non-invasive investigative tool for pregnant women with hip pain. Early detection can prevent complications and resorting to major surgeries. Key words: femoral neck fractures; osteoporosis; pregnancy
INTRODUCTION Transient osteoporosis is a rare, self-limiting,
idiopathic skeletal disease presenting as loss of bone density and thinning of the cortex.1 It usually affects middle-aged men or women in the third trimester of pregnancy or primiparous women just after delivery.1,2 The most common site involved is the hip (particularly on the left side)1,3; other sites include the vertebra, talus, knee, and acetabulum.3–5 25 to 30% of the patients have bilateral hip involvement.6,7 Femoral neck fractures usually occur 2 months after the onset of symptoms, when bone mass is at its lowest level.8 Only 6 cases of bilateral femoral neck fractures secondary to transient osteoporosis have been reported.9–14 CASE REPORT In February 2009, a 36-year-old primiparous woman presented with acute bilateral groin and hip pain aggravated by walking during the 6th month of twin pregnancy after in vitro fertilisation. She had been infertile for about 15 years. Radiography was declined by the patient because of concerns about dangers of ionising radiation. She was then prescribed
Address correspondence and reprint requests to: Dr Amir Reza Vosoughi, Research Center for Bone & Joint Diseases, Department of Orthopedic Surgery, Chamran Hospital, Shiraz University of Medical Sciences, Shiraz, Iran. E-mail:
[email protected]
Vol. 20 No. 2, August 2012 Bilateral subcapital femoral neck fractures secondary to transient osteoporosis during pregnancy 261
acetaminophen and bed rest. Four days after delivery by caesarean section, she presented again with painful hips. Radiographs showed bilaterally displaced subcapital femoral neck fractures (Fig.). Computed tomography and magnetic resonance imaging (MRI) showed lower bone density in the femoral heads than in the proximal femurs as well as bone resorption indicating old fractures (Fig.). Whole body bone scan showed increased uptake in both femoral necks and excluded bony metastasis. Bone densitometry indicated osteoporosis in the hips and spine. The patient did not drink alcohol or smoke, nor did she use anticonvulsants or corticosteroids. She was prescribed unfractionated heparin by an obstetrician. She did not have a history of any thyroid, parathyroid, metabolic, or bowel diseases. Blood tests for calcium, phosphate, 24-hour urine calcium, and creatine excretion; function tests for liver, thyroid, and kidney; blood cell count, C3, C4, ANA, ANCA-P, ANCA-C, anti-dS DNA, PPD test; and brucella antibody test were within normal range, except for the erythrocyte sedimentation rate (125 mm/hr) and C-reactive protein (48 mg/L). Because the hip fractures were old and displaced and bone quality was poor, internal fixation was not feasible and 2-stage bilateral bipolar modular hemiarthroplasty was therefore performed (Fig.). Early ambulation and rehabilitation was allowed. Pain subsided completely and full function was achieved gradually. At the 2-year follow-up, she was well with acceptable function of both hips. DISCUSSION Transient demineralisation during pregnancy was first reported about 50 years ago in 3 pregnant women.15 This entity is also known as transient osteoporosis,16 bone marrow oedema syndrome, regional migratory osteoporosis, transient migratory
osteoporosis, and hip algodystrophy.17 It occasionally affects lactating mothers and slender primiparous women in their third trimester of pregnancy. It usually affects a single or both hips (simultaneously or sequentially).1,3,18 Recurrence in later pregnancy has also been reported.19 Its risk factors include poor nutrition, low calcium intake, and a family history of osteoporosis.10 The exact aetiology is unknown; chemical, hormonal, mechanical, genetic, viral infection, and neurovascular theories have been proposed.5,7,20 The most accepted mechanism is microvascular injury, which leads to tissue ischaemia and then marrow oedema.21 The course of transient osteoporosis is benign and eventually recover within 6 to 12 months.6,7 During the first phase (first 2 months), hip pain and limp are noted; radiographs are normal and diffuse oedema is noted on MRI. In the second phase, symptoms increase and radiographs show osteoporosis with a normal joint space. Homologous focal lesions are specific MRI features. In the third phase (6 to 12 months), recovery and return to function can be expected, with MRI gradually returning to normal. Differential diagnosis includes pubis symphysiolysis, septic arthritis, malignancy, synovial disorders, reflex sympathetic dystrophy, and osteonecrosis. The latter is most difficult to treat. The pattern of pain in transient osteoporosis is of sudden onset, induced by weight bearing, and alleviated by rest. Whereas the pain characteristics in osteonecrosis are insidious in onset, continue at rest, and gradually increase without spontaneous recovery.22 Radiography cannot help in the diagnosis of transient osteoporosis in the first phase; MRI is the best noninvasive investigative tool for pregnant women with hip pain, in whom arthralgia and musculoskeletal discomfort is often considered to be normal.2,3,23 MRI shows diffuse homogenous lesion without collapse in the proximal femur, which is hyperintense in T2weighted images and hypointense in T1-weighted
Figure Bilateral subcapital femoral neck fractures with low bone density in the femoral heads treated with bilateral bipolar modular hemiarthroplasty.
262 MJ Emami et al.
images.23,24 Early detection using MRI can prevent complications and resorting to major surgeries. Fracture of the femoral neck or acetabulum is rare in pregnant women with transient osteoporosis. Bilateral fractures are rare.9–14 Most such patients are Asian people9,10,12 Pre-existing osteoporosis, old age, and loss of bone mass 2 months after the onset are risk factors.25 Osteoporosis induced by long-term use of heparin has been reported.26,27 Osteoblast inhibition
Journal of Orthopaedic Surgery
may occur in vivo with unfractionated heparin.28 Our patient had been prescribed unfractionated heparin during pregnancy, which may be a cause of osteoporosis. Treatment for young patients with a femoral neck fracture is closed reduction and internal fixation. Had the fractures been diagnosed earlier, our patient would not have undergone bipolar hemiarthropalsy, which is more costly and associated with more complications and the need for revision surgery in future.
REFERENCES 1. Cohen I, Melamed E, Lipkin A, Robinson D. Transient osteoporosis of pregnancy complicated by a pathologic subcapital hip fracture. J Trauma 2007;62:1281–3. 2. Chowdhury FU, Robinson P, Grainger AJ, Harris N. Transient regional osteoporosis: a rare cause of foot and ankle pain. Foot Ankle Surg 2006;12:79–83. 3. Debnath UK, Kishore R, Black RJ. Isolated acetabular osteoporosis in TOH in pregnancy: a case report. South Med J 2005;98:1146–8. 4. Ofluoglu O, Ofluoglu D. A case report: pregnancy-induced severe osteoporosis with eight vertebral fractures. Rheumatol Int 2008;29:197–201. 5. Lloyd JM, Lewis M, Jones A. Transient osteoporosis of the knee in pregnancy. J Knee Surg 2006;19:121–3. 6. Ma FY, Falkenberg M. Case reports: transient osteoporosis of the hip: an atypical case. Clin Orthop Relat Res 2006;445:245– 9. 7. Pai WC, Lin CY, Kao MJ, Lin FC. Transient osteoporosis of the hip during pregnancy: a case report. Tw J Phys Med Rehabil 2009;37:131–7. 8. Paraschou S, Makiev G, Anastasopoulos H, Flegas P, Karanikolas A. Transient osteoporosis of the hip: a report of 12 cases. EEXOT 2009;60:186–90. 9. Willis-Owen CA, Daurka JS, Chen A, Lewis A. Bilateral femoral neck fractures due to transient osteoporosis of pregnancy: a case report. Cases J 2008;1:120. 10. 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;128:313–6. 11. Munker R, Niedhart C, Niethard FU, Schmidt-Rohlfing B. Bilateral fracture of the femoral neck following transient osteoporosis in pregnancy [in German]. Z Orthop Ihre Grenzgeb 2007;145:88–90. 12. Wattanawong T, Wajanavisit W, Laohacharoensombat W. Transient osteoporosis with bilateral fracture of the neck of the femur during pregnancy: a case report. J Med Assoc Thai 2001;84(Suppl 2):S516–9. 13. Csotye J, Sisak K, Bardocz L, Toth K. Bilateral spontaneous displaced femoral neck fractures during pregnancy. J Trauma 2010;68:E115–6. 14. Leistedt S, de Marneffe P, Burette JL, Cornette M. Image of the month. Spontaneous bilateral fracture of the femoral neck resulting from transitory osteoporosis of pregnancy [in French]. Rev Med Liege 2004;59:622–3. 15. Curtiss PH Jr, Kincaid WE. Transitory demineralization of the hip in pregnancy. A report of three cases. J Bone Joint Surg Am 1959;41:1327–33. 16. Lequesne M. Transient osteoporosis of the hip. A nontraumatic variety of Sudeck’s atrophy. Ann Rheum Dis 1968;27:463–71. 17. Tran HA, Petrovsky N. Pregnancy-associated osteoporosis with hypercalcaemia. Intern Med J 2002;32:481–5. 18. Shifrin LZ, Reis ND, Zinman H, Besser MI. Idiopathic transient osteoporosis of the hip. J Bone Joint Surg Br 1987;69:769–73. 19. Khovidhunkit W, Epstein S. Osteoporosis in pregnancy. Osteoporos Int 1996;6:345–54. 20. Korompilias AV, Karantanas AH, Lykissas MG, Beris AE. Transient osteoporosis. J Am Acad Orthop Surg 2008;16:480–9. 21. Rishi V, Wahi P, Mahajan A. Transient osteoporosis of hip (migratory). JK Science 2008;10:194–6. 22. Gunaratne I, Singh P, Dega R. Transient migratory osteoporosis of the foot. Foot Ankle Surg 2007;13:51–4. 23. Axt-Fliedner R, Schneider G, Seil R, Friedrich M, Mink D, Schmidt W. Transient bilateral osteoporosis of the hip in pregnancy. A case report and review of the literature. Gynecol Obstet Invest 2001;51:138–40. 24. Bezer M, Gokkus K, Kocaoglu B, Erol B, Guven O. Transient osteoporosis of the hip in pregnancy: a report of three cases [in Turkish]. Acta Orthop Traumatol Turc 2004;38:229–32. 25. Nguyen TV, Center JR, Eisman JA. Femoral neck bone loss predicts fracture risk independent of baseline BMD. J Bone Miner Res 2005;20:1195–201. 26. Casele H, Haney EI, James A, Rosene-Montella K, Carson M. Bone density changes in women who receive thromboprophylaxis in pregnancy. Am J Obstet Gynecol 2006;195:1109–13. 27. Backos M, Rai R, Thomas E, Murphy M, Dore C, Regan L. Bone density changes in pregnant women treated with heparin: a prospective, longitudinal study. Hum Reprod 1999;14:2876–80. 28. Matziolis G, Perka C, Disch A, Zippel H. Effects of fondaparinux compared with dalteparin, enoxaparin and unfractionated heparin on human osteoblasts. Calcif Tissue Int 2003;73:370–9.
