Demonstration of myositis ossificans by 99mTc pyrophosphate bone scanning

Heterotopic Ossification: A Challenging Complication of Total Hip Arthroplasty: Risk Factors, Diagnosis, Prophylaxis, and Treatment

Background

This review is intended to summarize the risk factors, classification, diagnosis, and treatment of heterotopic ossification (HO) of previously published studies.

Results

Heterotopic ossification is a common complication of total hip arthroplasty. Its prevalence is not the same in all of the patient groups. Frequency of HO varies from 15 to 90%. Hip ankylosis, male gender, and previous history of HO are said to be risk factors with a significant level. Diagnosis is based on a single AP radiograph: the Brooker classification that divides HO into four grades is the most commonly used. The confirmation test that can be used is a bone scan. A great amount of bone metabolic turnover markers have been tested, but none of them seems to be relevant in case of prevention or diagnosis of HO. The most effective prophylactic treatment is radiotherapy or administration of nonsteroidal anti-inflammatory drugs. Over the years a lot of different RT protocols have been tested. Nowadays the most often used regimen is 7 Gy given postoperatively in a single dose. The most commonly prescribed drug in prophylaxis of HO is indomethacin. Also, the efficacy of ibuprofen and diclofenac was proven. Recently researchers focused on selective COX-2 inhibitors. They appear to be as effective as nonselective NSAIDs having less side effects. The one and only treatment of HO is a revision arthroplasty.

Studies on the Labeling of Ethylenediaminetetramethylene Phosphonic Acid, Methylene Diphosphonate, Sodium Pyrophosphate and Hydroxyapatite with Lutetium-177 for use in Nuclear Medicine

For the treatment of skeletal metastasis, a therapeutic radionuclide tagged with a bone seeking ligand is required, while for radiation synovectomy (RS), a therapeutic radionuclide irreversibly attached to pre-formed particles of appropriate size is required. Radio lanthanides are mostly therapeutic, and ligands containing phosphate groups are predominantly bone seekers. Exploiting these facts, number of new therapeutic radiopharmaceuticals could be developed. Labeling of four phosphate containing materials was pursued in the present study. It was hypothesized that various ¹⁷⁷Lu-labeled bone-seeking complexes such as ¹⁷⁷Lu-ethylenediaminetetramethylene phosphonic acid (EDTMP), ¹⁷⁷Lu-methylene diphosphonate (MDP) and ¹⁷⁷Lu-pyrophosphate (PYP) could be developed as agents for palliative radiotherapy of bone pain due to skeletal metastases, and ¹⁷⁷Lu-Hydroxyapatite (HA) could be developed as an agent for radiosynovectomy of small joints. Lyophilized kit vials of EDTMP, MDP and sodium pyrophosphate (Na-PYP) were formulated. HA particles were synthesized locally and purity was checked by high-performance liquid chromatography (HPLC). ¹⁷⁷Lu was labeled with EDTMP, MDP, PYP, and HA and the behavior of all was studied by radio-thin layer chromatography (TLC) radio-HPLC and radio-electrophoresis. Radio-TLC confirmed the labeling. HPLC analysis too verified the labeling. Radio-electrophoresis results depicted peaks for ¹⁷⁷Lu-MDP, ¹⁷⁷Lu-EDTMP and ¹⁷⁷Lu-PYP at 3.37 ± 0.06 cm, 5.53 ± 0.15 cm and 7.03 ± 0.06 cm respectively confirming negative charge on each specie as all migrated toward positive anode. All 3 methods verified the labeling. The study demonstrated that EDTMP, MDP and PYP form stable complexes with ¹⁷⁷Lu in injectable solution form. HA particulates could too be labeled with ¹⁷⁷Lu with high radiochemical yields (>98%) in suspension form. Former three could be utilized as bone-pain palliation agents for the treatment of bone metastases, and the later could be applied for the treatment of Rheumatoid arthritis of small joints. The study has also indicated the possibility of developing other numerous radiolanthanide analogs with the potentials of possible use in radiation therapy.

Neurogenic heterotopic ossification in spinal cord injury

Neurogenic heterotopic ossification (NHO) is a frequent complication in spinal cord injury (SCI) that is often difficult to treat. This review emphasizes the incidence, risk factors and clinical signs of NHO in SCI patients. Although the exact pathophysiology underlying NHO in neurologic patients is not yet understood, different pathogenic mechanisms have been proposed in the literature. A selection of the most important theories will be given and discussed. Moreover the different diagnostic, therapeutic, and preventive methods currently used in NHO management after SCI will be reviewed.

Advantages of diagnostic nuclear medicine part 1: musculoskeletal disorders

Radionuclide scans with improved imaging techniques such as single-photon-emission tomography and three-phase scanning have become safe, well-established, and highly effective diagnostic tools in sports medicine. The greatest strengths of the techniques include providing early physiologic information about injury sites and evaluating large areas or the whole body in a single examination. As described and illustrated here, bone scans are particularly useful for diagnosing such musculoskeletal injuries as stress fractures, avulsion fractures, periostitis, myositis ossificans, and rhabdomyolysis.

Impact of clinically significant heterotopic ossification on functional outcome after traumatic brain injury

OBJECTIVE

To assess heterotopic ossification's (HO) impact on functional outcome after TBI.

DESIGN

Retrospective with matched control group, single center.

SETTING

TBI Model System of Care at the Medical College of Virginia of Virginia Commonwealth University, Richmond, VA.

PARTICIPANTS

Twenty-six patients with TBI and triple-phase bone scan confirmed HO were matched with 26 patients without clinical evidence of HO.

MAIN OUTCOME MEASURES

Acute and rehabilitation lengths of stay (LOS), Admission and Discharge Functional Independence Measure (FIM) scores, FIM change, FIM efficiency (FIM gains per week), and discharge disposition.

RESULTS

The two groups had similar acute care LOS. Patients with HO had significantly longer inpatient rehabilitation LOS and significantly lower FIM mobility and activities of daily living subscale scores on admission and discharge. FIM efficiency was significantly lower for the group with HO. Significantly fewer patients with HO were able to be discharged to home.

CONCLUSIONS

HO is associated with a poorer functional outcome; however, it is not clear whether HO causes the decreased function or whether it may serve more generally as an indicator of those patients who will not progress as far or as rapidly during inpatient rehabilitation.

Heterotopic ossification in the setting of neuromuscular blockade

OBJECTIVE

Heterotopic ossification (HO) is a disorder characterized by the formation of new bone in tissue that does not ossify under normal conditions. We report a series of 6 cases in which HO occurred in the setting of adult respiratory distress syndrome (ARDS). We wished to show that HO can occur after neuromuscular blockade and that these cases might provide additional evidence that HO is influenced by neural mechanisms.

METHODS

Cases of HO were selected from the consultation services at the Massachusetts General Hospital and the Brigham and Women's Hospital. Affected patients all had ARDS and had been treated with a neuromuscular blocking agent. Patients with a history of stroke, burn, head trauma, spinal cord injury, or joint replacement were excluded from this study.

RESULTS

Heterotopic bone appeared around large joints in a pattern identical to that seen in patients with paralysis, traumatic brain injury, severe burns, or trauma. New bone formation was self-limited over a period of 1-2 years. Alkaline phosphatase and technetium bone scan were sensitive ways of detecting early disease and monitoring disease activity. Medical therapies had limited benefit. Surgical excision of mature new bone appeared to be the only definitive therapy.

CONCLUSION

Neuromuscular blockade in the setting of ARDS appears to be an important risk factor for the development of HO. The similarity of these cases of HO occurring in patients with brain or spinal cord injury raises the possibility that neural mechanisms may be important in the pathogenesis of this disease. Whether the type of neuromuscular blocking agent and the duration of use are important determinants of disease severity remains to be determined.

[Non-traumatic myositis ossificans circumscripta]

BACKGROUND

Myositis ossificans circumscripta is a benign lesion with an acute course and may simulate a malignant tumor. It usually follows trauma to soft tissue.

CASE REPORTS

Case n. 1. A 13 year-old girl was admitted because of a painful inflammatory tumour in the left thigh. Initial X-rays were normal. Ultrasound imaging showed a heterogeneous echogenic mass with several extending shadow cones in the distal part of the vastus medialis muscle resembling a calcifying hematoma. Twenty days later, X-rays showed a vague calcified peripheral rim in the medial distal part of the thigh. White blood count was normal, and blood sedimentation rate was 46 millimeters in the first hour. CT scan showed a transparent zone between the lesion and the adjacent bone and a lucent central area, surrounded by a dense outer area consistent with myositis ossificans. Histological examination of the excised mass confirmed myositis ossificans. Two years later, the patient was asymptomatic and X-rays showed no ossification. Case n. 2. A 14 year-old girl suffered from pain in the right anterior hip area since 10 days. She denied any trauma. A firm mass was palpable in the anterior superior iliac spine area and X-rays revealed a calcific density. CT scan showed a dense bony mass in the right gluteus medius muscle clearly separated from the adjacent bony pelvis by a soft tissue plane. Histological examination of the excised mass confirmed myositis ossificans. One year later, the patient was asymptomatic and X-rays of the pelvis showed no ossification.

CONCLUSION

Myositis ossificans circumscripta is rare in children. CT scan suggests the benign nature of the lesion by demonstrating integrity of bony cortex and characteristic disposition of calcifications. The biopsy is not necessary if the diagnosis is certain. Surgery permits to reduce the evolution.

Coexistence of deep venous thrombosis and heterotopic ossification in the pediatric patient

A 14-year-old girl and a 15-year-old boy with severe traumatic brain injuries were noted to have marked asymmetry in the lower extremities. Clinical and radiologic evaluation demonstrated the coexistence of deep venous thrombosis (DVT) and heterotopic ossification (HO). These cases demonstrate that although DVT are rare in children, they can be present and may coexist with the more common presentation of a swollen lower extremity secondary to HO.

Sonographic diagnosis of heterotopic bone formation in spinal injury patients

A variety of stimuli including neurological insult may provoke primitive mesenchymal cells to differentiate into bone forming cells. Such a sequel following spinal cord injury can delay rehabilitation, enhance the spasticity and reduce the range of movement in the affected joint. It is characterised by an initial inflammatory phase followed by heterotopic bone formation. The early inflammatory lesion clinically mimics deep vein thrombosis, a developing pressure sore, infection, and tumour. An early diagnosis at a time of clinical uncertainty, before the plain radiographic features develop, has distinct advantages and therapeutic implications. The unique pathological evolution and maturation of the lesion is clearly demonstrated by sequential sonographic (ultrasonic) assessment with depiction of the 'zone phenomena' seen on histology. Sonographic scans in 7 spinal injury patients proved diagnostic, before there was radiographic evidence of bone formation, and confidently excluded HBF in a further 18 patients without any false negative results.

The role of ultrasound in the early diagnosis and management of heterotopic bone formation

Heterotopic bone formation (HBF) is one of the many causes of painful limb swelling and is well recognized as posing clinical, radiological, and pathological diagnostic difficulties. We have evaluated the use of sonography to determine its role in reaching a diagnosis at a time when symptoms are maximal and the radiological diagnostic features absent. Serial ultrasound examination identified unique 'zone phenomea' in a heterogeneous group of eight patients before the classic radiological features appeared. The zone transformation matches the evolution and maturation process described pathologically and forms the basis of an early definitive diagnosis in all cases. The sonographic features are specific for the condition, unlike the scintigraphic appearances. Although CT confirms the peripheral location of the calcification, the low cost, safety, and general availability of ultrasound scanning make it the optimum imaging method for diagnosing and monitoring heterotopic bone formation.

Early myositis ossificans: a new echographic sign

A case of soft tissue swelling of the thigh in which myositis ossificans developed is presented. A series of ultrasound examinations showed previously unreported changes which suggested the diagnosis. The use of ultrasound and other imaging modalities in this condition are discussed and the ultrasound appearances are related to the histology.

Bone scanning and photon absorptiometry in metabolic bone disease

Bone scan imaging with the current bone-seeking radiopharmaceuticals, the technetium-99m labelled diphosphonates, provides a functional display of skeletal metabolism and has dramatically improved our ability to investigate skeletal pathology. While the role of bone scanning in metastatic disease was recognized early, and welcomed by oncologists and other specialists alike, in the field of metabolic bone disease the realization of its potential value has been slower, with perhaps more reluctant acceptance. Nevertheless, the skeleton remains an extremely difficult organ to investigate, and a familiarity with bone scanning should be an essential part of the investigational armamentarium for anyone with an interest in the metabolic bone disorders. The measurement of bone mineral by photon absorptiometry is a relatively new technique, which is rapidly gaining acceptance. The ability to accurately detect and quantify changes in bone mass is potentially of considerable value in the diagnosis and management of osteoporosis. The technique provides us with an extremely important and powerful research tool but, at the present time, its role in clinical practice has yet to be established.

Treatment of calcinosis universalis with low-dose warfarin

Patients with calcinosis universalis secondary to dermatomyositis or systemic sclerosis have increased levels of the calcium-binding amino acid, gamma-carboxyglutamic acid. The enzyme that effects gamma carboxylation of glutamic acid is warfarin-sensitive. Four patients with calcinosis universalis were treated with 1 mg per day of warfarin for 18 months in a non-blind initial study. Two patients had both decreased gamma-carboxyglutamic acid urinary concentration and decreased extra-skeletal uptake on technetium 99m-diphosphonate whole-body nuclear scanning. In a subsequent double-blind placebo study, two thirds of the patients receiving 1 mg per day of warfarin had decreases in extra-skeletal nuclear tracer uptake after 18 months, compared with none of the four patients receiving placebo. No patient had a change in clinical assessment, bleeding complication, or baseline normal prothrombin time. This low-dose warfarin regimen appears to have no demonstrable adverse effects, and these results suggest a beneficial effect on the progression of calcinosis in these rheumatic diseases.

99mTc-methylene diphosphonate and 67Ga-uptake in myositis ossificans

A histologically proven case of myositis ossificans is presented. Both 99mTc-MDP and 67Ga imaging demonstrated extensive uptake of radiotracers in the lesion.

Effects of acute administration of ethane hydroxydiphosphonate (EHDP) on skeletal scintigraphy with technetium-99m methylene diphosphonic acid (Tc-MDP) in the rat

A study has been performed in the rat to assess the effect of EHDP on the distribution of 99Tcm-labelled MDP used for skeletal imaging. Profound alterations in bone, kidney and blood levels were observed. These observations cast doubt on the value of bone scans for monitoring the therapeutic effect of diphosphonates.

Bone trauma and related benign disease: assessment by bone scanning

The radionuclide investigation of skeletal trauma in the past was confined generally to scintimetry and an occasional bone scan. The development of improved radiopharmaceuticals, including 99mTc-labeled compounds with their enhanced sensitivity, and the refinement of imaging devices offering superior resolution and speed have allowed a more detailed assessment of conditions resulting from trauma. Practical approaches to the diagnosis of subtle bone injury resulting in stress fracture, the differentiation between delayed healing and nonunion, and early recognition of avascular necrosis and osteomyelitis are now available. The changing pattern of radionuclide uptake in bone following damage by radiation and other abnormalities as a consequence of trauma also can be easily studied.

Bone and marrow imaging in sickle cell disease: diagnosis of infarction

Sickling of erythrocytes in patients with S-hemoglobin causes marrow and bone infarction. The former can be demonstrated as a lack of 99mTc-sulfur colloid uptake on marrow imaging examination. These defects may resolve or persist long after the acute episode. If the bone is involved in the acute episode, imaging within the first few days of onset of symptoms can show lack of 99mTc-labeled phosphate uptake, usually in a smaller area than that shown by marrow scanning. Follow-up bone imaging shows increased activity, particularly along the circumference of the bone where periosteal reaction can be demonstrated radiographically. Magnification by use of the pinhole collimator provides better definition of the uptake defect and the distribution of the increased reactive uptake. Timing of examination is important. If marrow imaging is performed in an asymptomatic period, the repeat examination during a painful crisis permits differentiation of old and acute marrow infarction. If 99mTc-phosphate imaging is performed after about 2 days of symptoms, acute infarction can be differentiated from osteomyelitis, which it may mimic clinically. Although osteomyelitis may cause no increased activity in the first 48 hr after onset of symptoms, it is characterized by intense focal activity thereafter (see article by Handmaker in this issue). To assist in differentiating bone infection in a site of marrow infarction demonstrated by marrow imaging, serial bone imaging with magnification may be useful. The uptake defect, followed in several days to 2 weeks, by circumferential increased activity, is a different pattern than the homogeneously intense activity of osteomyelitis, but the peripheral distribution may not be apparent on routine imaging. It is hoped that the utilization of these techniques can decrease the emotional and economic costs of prolonged hospitalization for suspected infection and can also expand our knowledge of the complex pathophysiologic changes of sickle cell bone disease.

The bone scan in inflammatory osseous disease

The 99mTc-phosphate bone scan has become a sensitive, reliable, and safe method for evaluating the patient with suspected inflammatory disease of bone. The scan may become positive as early as the first 24 hr after the symptoms and 10-14 days before roentgenographic changes occur. It can be used to differentiate successfully a variety of diseases from osteomyelitis, and in conjunction with 67Ga-citrate scan has become a mainstay in the work-up of the patient with infectious disease. Applications of the bone scan to infectious diseases in pediatric practice are especially helpful, since these diseases are common problems in this age group. Increased experience with the 99mTc-phosphate bone scan has already defined several areas of "limitations" in evaluating inflammatory disease. "Cold" defects, negative scans in early stages of osteomyelitis, and "extended uptake" may all pose problems in interpretation, but careful correlation of the bone scan results with clinical history and physical findings, blood cultures, and roentgenography will significantly reduce these problems.

The place of bone scan in the diagnosis of renal cell carcinoma

We herein review 12 cases of renal cell carcinoma evaluated by bone scan and skeletal survey. Comparison of these techniques revealed a high incidence of falsely negative results (42 per cent) when using skeletal survey alone. It is now our policy to include the bone scan in our initial evaluation of patients with renal cell carcinoma.