Metastatic Acetabular Fractures: Evaluation and Approach to Management

Transcription

1 502 Journal of Pain and Symptom Management Vol. 32 No. 5 November 2006 Palliative Care Rounds Metastatic Acetabular Fractures: Evaluation and Approach to Management Priya C. Singh, MD, Dipak V. Patel, MD, and Victor T. Chang, MD Department of Medicine (P.C.S., V.T.C.), UMDNJ/New Jersey Medical School, Newark, New Jersey; and Orthopedic Surgery Section, Surgery Service (D.V.P.) and Hematology/Oncology Section, Medical Service (V.T.C.), Veterans Administration New Jersey Health Care System, East Orange, New Jersey, USA Abstract Although bone metastasis to the acetabulum can cause significant disability from pain and immobility, little has been written about the diagnosis and management of a pathologic acetabular fracture. We present three patients with metastatic acetabular fractures and discuss an approach to evaluation and management. When a high index of suspicion of fracture exists, further radiographic workup is warranted. Management requires a multidisciplinary approach. Factors such as age, associated comorbidities, natural history of the underlying primary cancer, general health status, prognosis, acetabular fracture characteristics, and quality of bone should be considered. We briefly discuss the options available to nonoperative candidates. J Pain Symptom Manage 2006;32:502e507. Ó 2006 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved. Key Words Metastases, cancer, acetabulum, palliative care, esophageal cancer, prostate cancer, rectal pain Introduction Metastatic deposits to the acetabulum cause significant pain and functional disability, especially when the weight-bearing aspect of the acetabulum is involved. Patients with metastatic acetabular fractures can present with vague, diffuse groin pain or hip pain. The evaluation and management of these patients is a challenging problem. In this paper, we present Address reprint requests to: Victor T. Chang, MD, Section Hematology/Oncology (111), VA New Jersey Health Care System, 385 Tremont Avenue, East Orange, NJ 07019, USA. victor.chang@med.va.gov Accepted for publication: May 11, Ó 2006 U.S. Cancer Pain Relief Committee Published by Elsevier Inc. All rights reserved. three patients with metastatic acetabular fractures and discuss a decision-making approach. Case 1 An 84-year-old man with a history of hormone-refractory prostate cancer presented with hip pain and difficulty moving his hips for six weeks. When initially diagnosed with hormone-refractory, Gleason 9 (4 þ 5) disease, he enrolled in a Phase II trial of docetaxel and celecoxib. His course was complicated by the development of a right leg deep venous thrombosis. The day after Greenfield filter placement, he noted increasing pain in both hips, limiting his ability to ambulate. He rated the pain intensity as 4e5/10 (10 ¼ worst). Both hips were found to be tender on physical examination /06/$esee front matter doi: /j.jpainsymman

2 Vol. 32 No. 5 November 2006 Metastatic Acetabular Fractures 503 The active range of motion of both hips was restricted by pain and the passive range of motion was associated with moderate discomfort. He had an antalgic gait. It was difficult to assess the power in both hips due to pain. The anteroposterior (AP) and frog leg views of both hips showed no evidence of fracture. A computed tomography (CT) scan of the hips using 1.5 mm columnation showed a nondisplaced pathologic fracture through the posterior column and medial wall of the left acetabulum (Fig. 1) and a nondisplaced fracture through the anterior column of the right acetabulum. Protected weight-bearing ambulation using a walker was recommended. He completed chemotherapy and he remains ambulatory. Case 2 A 55-year-old man with recurrent esophageal cancer presented with progressive left hip pain for six months. When first diagnosed two years earlier, he underwent neoadjuvant chemoradiation followed by esophagectomy with gastric pull-up. Recurrence of the cancer was first thought be localized and was treated with esophageal dilatation and Wilson Cook stent placement. The shooting pain in his left leg began insidiously, especially during hip flexion and rotation. An AP radiograph of the left hip at that time showed no fractures and a radioisotope bone scan only showed evidence of rib metastasis. Subsequently, the left hip pain worsened and was exacerbated by weight bearing, as well as by flexion and external/internal rotation of the hip. A repeat AP radiograph of the left hip showed joint degeneration, proximal femoral endosteal scalloping, and osteopenia. The patient insisted on leaving the hospital before any further evaluation could be performed. One week later, he returned with new-onset rectal pain of a few days duration and dripping stool. The perirectal pain was sharp and shooting, and he described it like someone is rubbing sand into the skin. The pain was exacerbated by movement of the left hip. He had poor sphincter tone with guaiac positive brown stool. There was no back pain or saddle anesthesia, and leg strength and reflexes were intact. His rectal pain improved with hydromorphone 2 mg intravenously every 4 hours, but he continued to experience excruciating rectal pain with bowel movements and changing position in bed. The impression was a pelvic process or preherpetic infection. He developed a fever and died on the second day in the hospital. Autopsy examination showed widespread metastatic adenocarcinoma of the heart, lungs, temporal lobe, skull, ribs, left hip, adrenal glands, and kidneys. Dissection of the left acetabulum showed nondisplaced fractures, necrotic soft tissue and bone. Histopathologic Fig. 1. Computer tomographic image demonstrating bilateral acetabular fractures. Nondisplaced fracture through the medial wall of the left acetabulum, and anterior wall of the right acetabulum.

3 504 Singh et al. Vol. 32 No. 5 November 2006 examination showed metastatic adenocarcinoma. The remainder of the pelvis was normal and the bowel was unremarkable except for multiple diverticuli in the left descending colon and sigmoid colon, and foci of mucosal hemorrhage and congestion in the rectum. No abnormalities were noted in the spinal cord, but metastases were present in the left temporal lobe, leptomeninges, and dura mater. Case 3 A 72-year-old man with colon cancer presented with right hip pain. Four years earlier, he had a left hemicolectomy for adenocarcinoma of the colon. His medical comorbidities included sick sinus syndrome, atrial fibrillation, hypertension, hyperlipidemia, stroke, and chronic renal insufficiency. The new right hip pain had been progressive for a month, but he was able to bear weight. The pain intensity was rated as 8/10. On physical examination, he was able to ambulate without assistance, but there was pain on internal rotation of the hip joint. An AP radiograph of the right hip was equivocal for the presence of bone lesions. Radioisotope bone scan showed increased uptake in the right acetabulum extending to the right ischium. CT scan showed a cm destructive lesion in the posterior column of the right acetabulum consistent with a metastatic focus (Fig. 2). He received 3000 cgy of radiation therapy in 10 fractions for pain control and protected weight bearing was recommended. Discussion Acetabular fractures typically present as groin pain exacerbated by weight bearing. Pain in the medial thigh and knee can indicate acetabular disease or femoral head destruction. Passive range of motion at the hip joint usually is painless unless there is involvement of the proximal femur. If there is an inability to actively flex or abduct the hip in the supine position, then severe intertrochanteric disease should also be considered. 1 The complex three-dimensional structure of the acetabulum makes radiographic diagnosis of fractures difficult. Plain radiography remains the first step in the imaging workup. An AP view is necessary and Judet oblique views are recommended to evaluate the anterior and posterior columns of the acetabulum. 2 Subtle, nondisplaced acetabular fractures are not always detected on plain radiographs, especially when bowel gas shadow is superimposed on the pathologic lesion. If a fracture is suspected, a CT scan is recommended to assess fracture geometry, degree of displacement of the fracture fragments, and extent of comminution of the fracture. Fig. 2. Computer tomographic image demonstrating bilateral acetabular fractures. Non displaced fracture through the medial wall of the left acetabulum and anterior wall of the right acetabulum.

4 Vol. 32 No. 5 November 2006 Metastatic Acetabular Fractures 505 When an occult fracture is noted on CT scan, the diagnostic differential includes acetabular insufficiency fractures and metastasis, which present similarly and occur in the same patient population. 3 Insufficiency fractures are usually seen in patients with osteoporosis, rheumatoid arthritis, corticosteroid use, or history of radiation therapy. 4 On magnetic resonance imaging (MRI), there is a characteristic low-intensity linear area representing the fracture line and the presence of early medullary bone edema when an insufficiency fracture is present. 3,5 The first patient had a typical presentation of hip pain exacerbated by weight bearing. Plain films failed to demonstrate the bilateral acetabular fractures seen on CT scan. The second patient also experienced significant hip pain limiting weight bearing. Again, plain radiographs were normal, but metastatic acetabular fracture was confirmed on autopsy. These cases emphasize the importance of considering metastatic acetabular fractures as an etiology of hip pain even in the presence of normal radiographs. In a study of supracetabular fractures, plain radiographs were normal in 67% of cases and showed a sclerotic band indicative of pathology in only 25% of cases. 3 Further imaging workup (including radioisotope bone scan, CT scan, and MRI) should be pursued when metastatic acetabular fractures are clinically suspected and plain radiographs are not diagnostic. The third patient had hip pain due to metastatic involvement of the acetabulum confirmed by CT scan. The second patient presented with significant rectal pain with no findings on autopsy to explain his pain. The shooting nature appeared more consistent with a neuropathic process and its acute onset seemed inconsistent with diabetic neuropathy. We propose that his acetabular fracture caused referred rectal pain. Kim and Azuma have shown that the acetabular labrum is rich in nerve endings suggesting a role in nociception and propioception. 6 The labrum is innervated by a branch of the nerve to the quadratus femoris muscle and the obturator nerve. 7 Nociceptive impulses may be referred to the sacral plexus and subsequently via the pudendal nerve to the inferior rectal nerve that innervates the external anal sphincter. Another mechanism for referred rectal pain may have been direct tumor involvement of the pudendal nerve as it traversed the acetabulum. Operative Management When acetabular fracture is confirmed, the general indications for surgery include life expectancy greater than one month, ability to medically tolerate surgery, sufficient intact bone, and an expected benefit from the operation permitting mobilization and general improved quality of life. Other factors in the decision to operate on metastatic acetabular lesions include continued debilitating pain and immobility despite restricted weight bearing, systemic antineoplastic therapy, and analgesic therapy; continued symptoms for 1e3 months after localized radiation therapy; or pathologic fracture of the acetabulum or ipsilateral femur, or an impending ipsilateral femoral fracture. 8 Patient selection can be difficult. Three general surgical options are popular depending on the defects: 1) reconstruction of the acetabular defect using pins or screws and cement with a cemented acetabular component, 2) resection of the diseased bone with a hemipelvis prosthesis used for reconstruction, and 3) resection of the pubic rami and acetabulum and reconstruction using a saddle prosthesis that articulates between proximal femur and remaining ileum. 8 Two large series have been reported on surgery for metastatic acetabular disease. In one, 58 patients who received hip arthroplasty for metastatic acetabular fractures and fracturedislocations were divided into five operative treatment groups dependent on the extent and involvement of disease. 9 Sixty-seven percent of patients had excellent or good pain relief six months postoperatively and 43% reported these results two years postoperatively. Eighty percent were ambulatory six months postoperatively and 45% could walk two years postoperatively. Five patients had loosening of the prosthetic component from local tumor recurrence. There were two operative mortalities and the mean survival was 19 months. 9 In another series, 55 patients underwent surgical reconstruction for metastatic acetabular disease. Fifty-four patients received a combination of screws or pins and cement with a cemented protrusion acetabular component

5 506 Singh et al. Vol. 32 No. 5 November 2006 combined with total hip replacement. One patient received a hemipelvis endoprosthesis with total hip replacement. Thirty-four patients had significant pain relief at three months. Postoperatively, nine of 18 non-ambulatory patients regained their ability to walk, and 14 of 17 ambulatory patients preserved their ambulation. Five patients had prosthetic loosening due to recurrent disease. There was one perioperative mortality and median survival was nine months. 10 Nonoperative Management For those patients who do not require surgery, or are not operative candidates, palliative therapy should be provided as follows: 1. Analgesia: A combination of a nonsteroidal anti-inflammatory drug and an opioid can improve pain control in patients with cancer pain. 11 Movement-related breakthrough pain should be addressed with rescue medication. The role of bisphosphonates in patients with pain from acetabular metastases requires further investigation. A recent Cochrane analysis concluded that while there may be some effectiveness, bisphosphonates should be considered in bone pain only when analgesics and or radiotherapy are inadequate Supportive weight bearing: The use of crutches, a cane or a wheelchair may reduce the risk of fracture and relieve pain by decreasing force on the weightbearing bones Systemic therapy: Treating the underlying disease with chemotherapy and hormonal therapy may provide pain relief. 4. Radiation therapy: The Expert Panel for the Radiation Oncology Bone Metastasis Working Group suggested 20 Gy in five fractions, 30 Gy in 10 fractions, or 35 Gy in 14 fractions as the appropriate dose for initial treatment of metastatic bone disease. 13 The Radiation Therapy Oncology Group recently completed a randomized trial that compared 8 Gy in one fraction to 30 Gy in 10 fractions in 949 patients with bone metastases from breast or prostate cancer. Approximately half the patients had lesions of weight-bearing sites, but the study did not include patients with acetabular metastases. At a three-month follow-up, there was no difference between the arms. 14 These results confirm earlier studies with single fraction dosing for bone metastases. Although there are few references on the specific use of radiation therapy for acetabular metastases, one study of external beam radiation in 14 patients with acetabular metastases from breast cancer demonstrated pain relief in all. 15 High-dose brachytherapy was successfully used in a previously radiated acetabulum without bone necrosis in a patient with locally recurrent sarcoma Injections: Methylmethacrylate and ethanol injections into the osteolytic lesion are palliative procedures with the aim of providing fast pain relief. Methylmethacrylate or acrylic bone cement provides significant pain relief in as little as 4 hours after injection. 17 It polymerizes to form hard bone cement that can stabilize microfractures of the acetabular roof and thus may improve mobility. 17 In a study by Cotten et al., all 11 patients studied had improved mobility 1e5 days after an injection. 18 Ethanol injections are only used for pain relief when extensive osteolysis and soft tissue infiltration is present. It provides regional anesthesia by destroying the nociceptive nerve pathways for weeks to months. 19 These injections may be performed concurrently if both weight-bearing parts and nonweight-bearing parts of the acetabulum are involved or if there is extensive soft tissue infiltration. Radiofrequency ablation can provide pain relief in patients with lytic bone lesions, including pelvic lesions, and may be suitable for carefully selected patients with acetabular metastases. 20 Conclusion Bone metastasis to the acetabulum can cause pain and disability. A high index of suspicion is needed and a radiologic workup beyond plain hip films may be warranted so that such occult fractures are not missed. Surgery is appropriate in carefully selected cases.

6 Vol. 32 No. 5 November 2006 Metastatic Acetabular Fractures 507 If surgery is not appropriate, a comprehensive approach to palliation should be considered. Radiofrequency ablation can provide pain relief in patients with lytic bone lesions, including pelvic lesions, and may be suitable for carefully selected patients with acetabular metastases. 20 References 1. Boland PHJ. Metastatic disease. In: Callaghan JJ, Rosenberg AG, Rubash HE, eds. The adult hip, 1st ed. New York: Lippincott-Raven Publishers, 1998: 547e Towers J. Radiographic evaluation of the hip. In: Callaghan JJ, Rosenberg AG, Rubash HE, eds. The adult hip, 1st ed. New York: Lippincott-Raven Publishers, 1998: 333e Otte MT, Helms CA, Fritz RC. MR imaging of supra-acetabular insufficiency fractures. Skeletal Radiol 1997;26:279e Grangier C, Garcia J, Howarth NR, May M, Rossier P. Role of MRI in the diagnosis of insufficiency fractures of the sacrum and acetabular roof. Skeletal Radiol 1997;26:517e Newberg AH, Newman JS. Imaging the painful hip. Clin Orthop 2003;406:19e Kim YT, Azuma H. The nerve endings of the acetabular labrum. Clin Orthop Relat Res 1995;320: 176e Gagnard C, Godlewski G, Prat D, et al. The nerve branches to the external anal sphincter: the macroscopic supply and microscopic structure. Surg Radiol Anat 1986;8:115e Healey JH, Brown HK. Complications of bone metastases: surgical management. Cancer 2000;88: 2940e Harrington KD. The management of acetabular insufficiency secondary to metastatic malignant disease. J Bone Joint Surg Am 1981;63:653e Marco RA, Sheth DS, Boland PJ, et al. Functional and oncological outcome of acetabular reconstruction for the treatment of metastatic disease. J Bone Joint Surg Am 2000;82:642e Stockler M, Vardy J, Pillai A, Warr D. Acetaminophen (paracetamol) improves pain and well-being in people with advanced cancer already receiving a strong opioid regimen: a randomized, double-- blind, placebo-controlled cross-over trial. J Clin Oncol 2004;22:3389e Wong R, Wiffen PJ. Bisphosphonates for the relief of pain secondary to bone metastases. Cochrane Database Syst Rev 2002;2. CD Rose CM, Kagan AR. The final report of the expert panel for the radiation oncology bone metastasis work group of the American College of Radiology. Int J Radiat Oncol Biol Phys 1998;40: 1117e Hartsell WF, Scott CB, Bruner DW, et al. Randomized trial of short- versus long-course radiotherapy for palliation of painful bone metastases. J Natl Cancer Inst 2005;97:798e Cheng DS, Seitz CB, Eyre HJ. Nonoperative management of femoral, humeral and acetabular metastases in patients with breast carcinoma. Cancer 1980;45:1533e Martinez-Monge R, Perez-Ochoa A, San Julian M, Aquerreta D, Sierrasesumaga L. Bone HDR brachytherapy in a patient with recurrent Ewing s sarcoma of the acetabulum: alternative to aggressive surgery. Brachytherapy 2003;2:114e Cotten A, Demondion X, Boutry N, et al. Therapeutic percutaneous injections in the treatment of malignant acetabular osteolyses. Radiographics 1999; 19:647e Cotten A, Deprez X, Migaud H, et al. Malignant acetabular osteolyses: percutaneous injection of acrylic bone cement. Radiology 1995;197:307e Gangi A, Dietemann JL, Schultz A, et al. Interventional radiologic procedures with CT guidance in cancer pain management. Radiographics 1996; 16:1289e Goetz MP, Callstrom MR, Chardonneau JW, et al. Percutaneous image-guided radiofrequency ablation of painful metastases involving bone: a multicenter study. J Clin Oncol 2004;22:300e306.