Annals of the Rheumatic Diseases 1993; 52: 545-547 545

Clinical evolution of sacral stress fractures: Ann Rheum Dis: first published as 10.1136/ard.52.7.545 on 1 July 1993. Downloaded from influence of additional pelvic fractures

P Peris, N Guafiabens, F Pons, R Herranz, A Monegal, X Suris, J Mufioz-Gomez

Abstract Patients and methods Objectives-To evaluate the clinical Over a period of 34 months (March 1989 to evolution of sacral stress fractures in January 1992), 14 patients (12 women, two relation to the scintigraphic pattern and men) were diagnosed as having sacral the presence of additional pelvic fractures. The average age was 65 years (range fractures. 48-80 years). Their clinical records were Methods-This was a retrospective study reviewed to determine their presenting of 14 patients with sacral fractures. symptoms, the risk factors for fracture, and the Results-Six patients had additional clinical evolution. Special attention was paid to pelvic fractures. Four bone scintigraphic the chronological course of clinical symptoms. patterns were found. The resolution of Sacral plain film radiography and bone symptoms was longer in patients with scintigraphy were performed on all patients associated pelvic fractures (30 weeks v and, in five, computed tomography (CT) was three weeks). No relation was found also used. Lumbar bone mineral density between the bone scintigraphic pattern (BMD) was measured by dual photon and the time ofevolution. absortiometry (Lunar-DP3) in 11 patients. Conclusion-Associated pelvic fractures The diagnosis of sacral fracture was delay the resolution of symptoms in established on the basis of the presence of patients with sacral fractures, regardless compatible clinical data confirmed by one or ofscintigraphic pattern. more of the diagnostic methods, and a favourable outcome. Osteoporosis was defined (Ann Rheum Dis 1993; 52: 545-547) as a bone mineral density of the lumbar spine two standard deviations or more below the young normal values,8 or by the presence of http://ard.bmj.com/ Stress fractures are injuries that occur as a atraumatic spinal fractures, or both. result of repeated cyclic loading of the bone. Depending on the state of the bone affected, these fractures are divided into two types: Results fatigue fractures, which occur in bone with The most common presenting symptom was normal elastic resistance which has been diffuse low back pain, accompanied in five loaded to an unaccustomed degree, and patients by hip, buttock, or thigh pain. on September 25, 2021 by guest. Protected copyright. insufficiency fractures, which occur in Pertinent physical findings were limited to weakened bone. Several pathological tenderness on palpation of the sacrum and processes may decrease the elastic resistance of decreased range of low back motion. bone, and predispose it to the development of Moreover, five patients, those with additional insufficiency fractures. Osteoporosis is one of pelvic fractures, had groin pain. Five patients the most common associated conditions. had a previous history ofminor trauma, usually Fractures related to osteoporosis commonly a fall. None referred to previous unusual Hospital Clinic i affect the spine, pelvis, and femur. Sacral activity as a causative factor. Provincial, Barcelona, fractures are not uncommon, however, they All patients were diagnosed as having Spain may be overlooked.2 Characteristic osteoporosis. Characteristics ofthe patients are Metabolic Bone Diseases Unit. Service scintigraphic patterns ofthis fracture have been shown in the table. Lumbar BMD was ofRheumatology previously described.3 ' These fractures measured in 11 patients, all of whom had P Pens frequently occur in elderly women with osteoporosis. In addition, the lumbar BMD ,N Guafiabens A Monegal pronounced osteopenia, in whom histories of was below the fracture threshold in all cases. X Suns previous injury are usually absent.5-7 Data on In one patient a bone biopsy discounted J Muftoz-G6mez clinical symptoms, particularly on clinical concomitant osteomalacia. Service ofNuclear outcome, are scarce, and no reports have A retrospective review showed abnormalities Medicine been on the relation on in nine of F Pons previously published radiographs cases, consisting R Herranz between the scintigraphic pattern of sacral disruption, deformity or sclerosis of the sacral Correspondence to: fracture and the time to clinical outcome, or arcuate lines (fig 1), but the abnormalities were Dr P Peris, with the presence of additional pelvic often overlooked on the original reading. In Servicio de Reumatologia, Hospital Clinic i Provincial, fractures. five patients, CT was performed, confirming a Villarroel, 170, The aim was to evaluate the clinical sacral fracture in all. Other fractures, occurring Barcelona 08036, Spain. evolution of sacral fractures in relation to the either before or at the time of the sacral Accepted for publication scintigraphic pattern and the presence of fracture, were common. Compression 4 February 1993 additional pelvic fractures. fractures of the spine were present in 10 546 Pens, Guaniabens, Pons, et al

Characteristics ofthe patients patients, fractures of the pubis and ischium Sex/Age Diagnosis Scintigraphic Other Resolution were found in five, costal fractures in five, and pattern* fractures ofsymptoms fractures of the femoral neck and coccyx in one Ann Rheum Dis: first published as 10.1136/ard.52.7.545 on 1 July 1993. Downloaded from (weeks) each. All but one of the additional pelvic M/55 Cryptogenic cirrhosis c Spinal 3 fractures were diagnosed on the Liver transplant steroid therapy Costal original F/73 Postmenopausal osteoporosis d Spinal 4 reading, the one overlooked being a para- F/60 Primary biliary cirrhosis a Spinal 40 symphiseal fracture which was Costal initially Pelvis diagnosed by bone scintigraphy. F/70 Postmenopausal osteoporosis b Spinal 32 In all cases bone scintigraphy was Costal Pelvis performed, and all showed areas of increased F/73 Temporal arteritis steroid therapy c Spinal 4 radioisotope uptake in the sacrum. The F/54 Post-hepatitic cirrhosis c 2 Liver transplant steroid therapy scintigraphic abnormalities representing sacral F/78 Senile osteoporosis a Pelvis 32 fractures appeared in four patterns (table): Femur (a) M/48 Chronic alcoholism d Spinal 24 in the body of the sacrum and both sacral ala Pelvis (four cases), an H or F/58 Primary biliary cirrhosis d Spinal 2 giving butterfly shaped Liver transplant steroid therapy Femur appearance (fig 2); (b) in the body of the F/65 Polymyalgia rheumatica steroid therapy a Spinal 4 sacrum and one sacral ala (three cases); (c) in F/80 Senile osteoporosis b Costal 16 Coccyx both sacral ala (four cases); and (d) in a single F/67 Postmenopausal osteoporosis a Spinal 4 ala (three cases, one of them with focal F/63 Primary biliary cirrhosis b Spinal 2 Costal activity). F/74 Senile osteoporosis c Spinal 36 Five patients had concomitant pelvic Pelvis fractures. Two of them showed the first *See text for description ofpatterns. pattern, and the others, the second, third and fourth patterns. One patient had a simultaneous coccyx fracture; this fracture was also considered to be an additional pelvic fracture. All of the pelvic fractures could be evaluated on the original scintigraphic scan. Clinical follow up was carried out between six and 26 months (mean 16 months) after presentation. The average time from onset to resolution of the symptoms was 15 weeks (range 2-40), being much longer in patients with associated pelvic fractures than in patients with sacral fractures only (30 weeks (range 16-40 weeks) v three weeks (range 2-4 weeks)). No relation was found between the http://ard.bmj.com/ scintigraphic patterns and the average time of resolution of symptoms. Repeated bone scans were performed in two patients, two and seven months after the initial abnormal scan, showing a decreased uptake in the sacrum. All patients were treated with bedrest and non- steroidal anti-inflammatory drugs, and in eight on September 25, 2021 by guest. Protected copyright. cases subcutaneous calcitonin was added to the treatment. Four of these patients had associated pelvic fractures. The mean time to F'igure I Anteroposterior radiograph of the pelvis showing clinical outcome in patients with calcitonin discontinuity the sacral arc of first right (arrow). treatment was 18 weeks, whereas in the remaining patients it was nine weeks.

Discussion The present study clearly shows that additional pelvic fractures increase the time to clinical outcome. The time from onset to resolution of the symptoms in the patients with only sacral fractures was three weeks. In patients with associated pelvic fractures, however, the average time of resolution of symptoms was much longer, being 30 weeks. These results agree with previous reports, in which the average time to clinical outcome for sacral fractures varied from one to 12 months.5-7 In these reports, however, the role of additional pelvic fractures was not considered. Moreover, the clinical course of isolated stress fractures of Figure 2 Posterior view of a bone scan ofthe pelvis the pubic ramus is shorter, between six and 10 showing an increased uptake ofisotope in both sacral alae and in the body ofsacrum, giving a characteristic butterfly weeks, than that associated with sacral shaped pattern. fractures.' Clinical evolution of sacral stress fractures: influence of additional pelvic fractures 547

In accordance with previous reports, probably owing to the presence of concomitant postmenopausal and senile osteoporosis were pelvic fractures. the predisposing conditions in most patients5-7 The recommended treatment of sacral stress Ann Rheum Dis: first published as 10.1136/ard.52.7.545 on 1 July 1993. Downloaded from and, as has been recently described, liver fractures has several elements: reduced transplantation was the second most common physical activity, analgesic treatment, and in associated factor.'0 Clinical symptoms in this some cases the initiation of treatment for series varied from moderate to severe low back associated osteoporosis.7 In our patients, the pain and, additionally, all patients with pubic treatment consisted of management to reduce fractures had groin pain. There were no signs pain (bedrest, analgesics) and to treat the of radiculopathy, which rarely occurs.4 associated osteoporosis. The type of treatment Sacral insufficiency fractures are difficult to did not seem to affect the final outcome diagnose for several reasons. The findings on significantly. Eight of our patients received radiographs are very subtle and easily additional calcitonin therapy without a overlooked, requiring a careful examination. significant improvement; however, it is difficult The irregularity in the arcuate lines is a to evaluate this data because this is a sensitive indicator of a possible fracture." 12 retrospective study, and patients on calcitonin Another, and probably the most important therapy seemed to be more affected. reason, is the lack of awareness of this fracture. In conclusion, the time to resolution of Jackson et all" reported that, in a series of 50 symptoms in patients with sacral fractures is patients with pelvic ring fractures, concomitant not related, to the sacral scintigraphic pattern, sacral fractures occurred in 72%, 61% of these the concomitant fractures in the pelvic ring being overlooked at the time of the initial being the main factor influencing the clinical radiological interpretation. In our series, five of outcome. the 14 patients had associated pelvic fractures, and one patient had a fractured coccyx. In all but one, both processes occurred 1 Renner J B. Pelvic insufficiency fractures. Arthritis Rheum simultaneously. 1990; 33: 426-70. Bone 2 Cooper K L, Beabout J W, Swee R G. Insufficiency fractures scintigraphy is a sensitive test for of the sacrum. Radiology 1985; 156: 15-20. skeletal trauma. Fractures may be detected as 3 Ries T. Detection of osteoporotic sacral fractures with radionuclides. Radiology 1983; 146: 783-5. early as one day after their occurrence and, 4 Schneider R, Yacovone J, Ghelman B. Unsuspected sacral even in older patients, the bone scan is usually fractures: detection radionuclide bone scanning. Am 7 Roentgenol 1985; 144: 337-41. abnormal at the fracture site within 72 hours 5 Cotty Ph, Fouquet B, Mezengue C, et al. Fractures du of injury. Areas of increased isotope uptake sacrum par insuffisance osseuse. A propos de 10 cas. J Neuroradiol 1989; 16: 160-71. may persist for two or more years, depending 6 De Smet A A, Neff J R. Pubic and sacral insufficiency on the location and type of bone fracture." fractures: clinical course and radiologic findings. Am J Radionuclide Roentgenol 1985; 145: 601-6. bone scans of sacral fractures 7 Rawlings III C E, Wilkins R H, Martinez S, Wilkinson R may have several different appearances. In H. Osteoporotic sacral fractures: a clinical study. http://ard.bmj.com/ 4 Neurosurgery 1988; 22: 72-6. accordance with other authors,3 we found 8 Nordin BE C. The definition and diagnosis ofosteoporosis. four different scintigraphic patterns, the most Calcif Tissue Int 1987; 40: 57-8. characteristic one being butterfly shaped. 9 Paulov H, Nelson T, Warren R, Torg J, Burstein A. Stress fractures of the pubic ramus. J Bone J7oint Surg 1982; Unilateral or bilateral increased isotope uptake 64-A: 1020-5. 10 Peris P, Navasa M, Guaflabens N, et al. Sacral stress fracture in the sacral alae create less specific patterns, after liver transplantation. BrJ Rheumatol. In press. which may raise problems in distinguishing 1 1 Jackson H, Kam J, Harris J H, Harle T S. The sacral arcuate

lines in upper sacral fractures. Radiology 1982; 145: on September 25, 2021 by guest. Protected copyright. between fractures and infectious or 35-9. inflammatory processes of the sacrum.34 12 Northrop C H, Eto R T, Loop J W. Vertical fracture of the These two processes, be sacral ala. Significance of the non-continuity of the however, may easily anterior superior sacral foraminal line. Am Y Roentgenol differentiated by CT which, in doubtful cases, 1975; 124: 102-6. 13 Martin P. The appearance ofbone scans following fractures, is the most specific method of diagnosis.'4 In including immediate and long-term studies. J Nucd Med our patients, no relation was found between 1979; 20: 1227-31. 14 Davies A M, Evans N S, Struthers G R. Parasymphyseal and the scintigraphic patterns of sacral fractures associated insufficiency fractures ofthe pelvis and sacrum. and the time to clinical outcome, which was Bry Radiol 1988; 61: 103-8.