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M.W. CHAARANI
Department of Orthopaedics, Hamad Medical Corporation, PO Box 3050, Doha, Qatar
Keywords: Osteoid osteoma, femoral neck, percutaneous, extra articular excision
A simple new way for excision of intramedullary osteoid osteoma from the femoral neck without going through the hip
joint is described. A trephine hole starting distal to the great trochanter with fluroscopy guidance is used. This procedure
(for such a lesion) has not been reported in the literature
The surgical problems encountered with osteoid osteomas of the proximal femur are unique. En bloc surgical excision is often made difficult by problems in defining the tumour boundaries. This can lead to extensive resection requiring internal fixation or bone grafting, and increased risks of complications. Surgical exposure to the femoral neck is extensive by itself. In the submitted report excision biopsy of an intramedullary osteoid osteoma from the femoral neck was done through a trephine hole distal to the great trochanter through the medulla of the femoral neck, avoiding major exposure to the hip joint or even penetrating the hip joint, and the femoral neck cortex. This simplifies the operation and reduces the likelihood of complications. The accuracy of computed tomography (CT) and magnetic resonance imaging (MRI) in locating the exact site of the tumour, assisted in planning this procedure.
An eleven-year-old boy had pain in the right knee for about one year and in the right hip for the last four months. The right knee was clinically normal. The right hip showed slight restriction of movements. The patient had clinical and imaging study findings suggestive of an intramedullary osteoid osteoma of the femoral neck. The pain worsened and would wake him up at night. He took ibuprufen tablets that eased the pain for about six hours.
The tumour could be seen with difficulty on plain radiographs with slight sclerosis at the medial aspect of the neck of the right femur. There was increased uptake in the femoral neck with technetium - 99 MDP bone scintigraphy.
The operative strategy was based on findings from the preoperative bone scan (Figure 1), CT scan (Figure 2), and MRI (Figure 3). Plain radiographs showed a faint shadow (Figure 4) that helped in locating the tumour with the help of fluoroscopy during surgery.
An 8-mm trephine was used to reach the tumour with the help of a guide wire introduced under fluoroscopy. The remaining tumour area was removed by curette. All the bone removed was fixed in formalin and sent to the pathology laboratory for careful search for the nidus.
Postoperatively, there was immediate relief from the agonizing pain, and full recovery after surgery. No complications were reported. Full weight bearing was allowed after 24 hours. Histopathological evaluation confirmed the diagnosis. An immediate postoperative plain radiograph showed the excision track through the femoral neck (Figure 5). A few days after surgery a CT scan was done which confirmed excision of the nidus (Figure 6). The clinical result was excellent after nine months and the patient was pain free.
Osteoid osteoma was first described by Jaffe in 1935 as a benign neoplasm of bone. Since then, it has been found to respond well to total surgical excision. Osteoid osteoma comprises ten percent of all benign bone tumours. Osteoid osteomas are extremely painful and well localized. About eighty percent of osteoid osteomas occur in children and teenagers.1 Most of osteoid osteomas occur in the proximal femur. In one hundred consecutive patients with osteoid osteoma, forty occurred in the proximal femur.1 Osteoid osteoma can be intramedullary, intracortical or subperiosteal. The symptoms may mimic monoarticular arthritis.
Typical intracortical osteoid osteoma consists of a small radioluscent lesion surrounded by a thickened sclerotic rim, which may obliterate the lytic nidus. Osteoid osteomas are preferentially sited in the internal cortex of the femoral neck. Some osteoid osteomas are intramedullary, with minimal adjacent reaction. The major clinical symptom of osteoid osteoma is intermittent, progressive pain that is often worse at night. The pain, which may be alleviated by salicylates or other non steroidal anti-inflammatory drugs, can develop 6 to 12 months before radiographic changes are evident and the appropriate diagnosis is considered. The differential diagnosis includes monoarticular arthritis, psychoneurosis and malingering.
In patients having normal plain radiographs, isotopic bone scanning can show early lesions in the form of a focus of marked hyperactivity. Thin slice CT can show a calcified or uncalcified nidus, thus, strongly suggesting the diagnosis and allows an accurate evaluation of the tumour location within the bone.
Open surgery, which requires en-bloc resection of a big amount of bone from a comparatively small femoral neck, to decrease the chances of recurrence should be avoided as much as possible to minimize complications. These possible complications include femoral neck fractures and growth disturbance in children.
Intra-articular procedures may lead to serious joint complications such as avascular necrosis of the femoral head, septic arthritis, restricted movements due to capsular adhesions and heterotopic calcification. To reduce the chances of these complications an extracapsular subperiosteal approach has been adopted by some surgeons.2
These problems, together with the accuracy of CT and MRI in delineating osteoid osteoma, led to the utilization of percutaneous surgical methods in several centers. Bone scintigraphy can localize both the nidus and the reactive bone around it. Computed tomography and MRI are essential for evaluating lesions of the femoral neck and can demonstrate in which quadrant the lesion has developed.3 The rationale for these methods is that osteoid osteoma is a benign, focal lesion of limited size.
Figure 1: Technetium bone scan: focus of marked hyperactivity over the right femoral neck.
Figure 2: computed tomography scan (axial view) shows an intramedullary osteoid osteoma in the anterior half of the femoral neck.
Figure 3a: MRI (coronal examination) demonstrated a focal lesion in the medulla of the lateral half of the femoral neck.
Many percutaneous methods have been used during the last two decades. Percutaneous drill biopsy under CT guidance is becoming a more acceptable method of treatment.4,5 Some serious complications have been reported with this method; some patients have developed fractures at the drill biopsy site. Other complications have included local infection, nerve irritation and muscular haematomas.6
A number of other percutaneous techniques have been developed including radiofrequency ablation and laser photocoagulation.7,8 However, these methods do not always provide a specimen for histological assessment. Campanacci et al (1999) reviewed the literature and compared their open technique in 97 patients with 247 cases reported in the literature, in which percutaneous techniques of removal or coagulation of the nidus were used. They found the latter procedure was associated with a less constant rate of primary cure (100% vs. 83%).1
Figure 3b: MRI (axial examination) demonstrated a focal lesion in the anterior half of the femoral neck.
Figure 4: Plain x-ray of the right hip which shows a faint circular shadow (arrows) on the lateral aspect of the femoral neck.
Figure 5: Plain radiograph of the right hip that shows the excision track.
Figure 6: Computerised tomography scan (axial view) carried out a few days after the procedure to check that removal of the tumour was complete.
To the best of my knowledge, this report describes a new method to excise intramedullary and internal cortex osteoid osteomas in any quadrant of the femoral neck (medial, lateral, anterior and posterior). This is achieved without major exposures, or even going through the hip joint, and without weakening the femoral neck by drilling through its cortex, thus, simplifying the operation and reducing the likelihood of complications.
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Campanacci L.Osteiod osteoma: direct visual
identification and intralesional excision of the nidus with
minimal removal of bone. J Bone Joint Surg (Br)
1999; 81: 814-820
2. Mosheiff R, Robin G.C, Mattan Y, Sucher E. The
subcapsular approach for lesions of the femoral neck J
Bone Joint Surg (Br) 1993; 75: 331-332
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evaluated with isotopic bone scanning, CT, and MR
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tomography guided excision in the pediatric
patient. J Pediatric Orthop 1990; 10; 510-513
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efficacy of percutaneous drill-biopsy under computed
tomography guidance of osteoid osteomas of the hip
and femur. A review of seven cases. Joint Bone Spine
2000; 67(3): 204-209
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Morera-Maupome H, Railhac J. Osteoid osteoma:
CT- guided percutaenous resection and follow-up in
38 patients. Radiology 1999; 212: 687-692
7. Rosenthal DI, Springfield DS, Gebhardt MC, Rosenberg AE, Mankin HJ. Osteoid osteoma:
percutaneous radio frequency ablation Radiology
1995;197;451-454
8. Gangi A, Dietemann JL, Gasser B, Mortazavi R, Brunner PH, Mourou MY, Dosch JC, Durckel J,
Marescaux J, Roy C. Interstitial laser
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Radiology 1997; 203: 843-848
Copyright: 13 August 2002
Correspondence: M.W. Chaarani, Department of Orthopaedic Surgery, Hamad Medical Corporation, Doha, Qatar, P.O.Box 3050 E-mail: chaarani_ortho@hotmail.com
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