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Rotational acetabular osteotomy for acetabular dysplasia of the hip with a giant acetabular bone cyst: a case report
J Orthop Sci (2004) 9:99–102 DOI 10.1007/s00776-003-0742-7
Rotational acetabular osteotomy for acetabular dysplasia of the hip with a giant acetabular bone cyst: a case report Mitsuhiro Morita1, Harumoto Yamada2, Osamu Hemmi1, and Kyosuke Fujikawa1 1 2
Department of Orthopaedic Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa 359-8513, Japan Fujita Health University, Toyoake, Japan
Abstract In acetabular dysplasia of the hip joint accompanied by a giant acetabular bone cyst, rotational acetabular osteotomy may cause serious complications, such as bone necrosis after surgery or fracture of the fragile acetabulum during the operation. In a patient with this condition, we performed a two-stage operation: first, autogenous bone grafting supplemented with hydroxyapatite filling, then rotational acetabular osteotomy (after new bone formation had been assured). Radiographs and CT scans showed favorable fusion of the grafted bone. Some 18 months after the second operation, arthrograms showed no inflow of contrast medium from the articular cavity into the bone cyst region, although this had been observed before treatment. Thus, an effective remodeling of bony congruency was indicated in the mobile acetabulum 5 years after the second operation. This two-stage operation appears to be useful for correcting acetabular dysplasia accompanied by a giant bone cyst and to carry a reduced risk of serious complications, such as deterioration of the articular surface of the acetabulum or necrosis of the translocated acetabulum. Key words Rotational acetabular osteotomy · Acetabular dysplasia · Hip joint · Bone cyst · Two-stage operation
Introduction In this case report, we present evidence indicating that a two-stage operation for acetabular dysplasia of the hip with a giant bone cyst is useful in that it can make the procedure easier while reducing the risk of serious complications, such as acetabular fracture, deterioration of the articular surface of the acetabulum, and bone necrosis.
Offprint requests to: M. Mortia Received: August 8, 2003 / Accepted: October 15, 2003
Case report A 48-year-old woman complaining of pain in her right hip joint and claudication was referred to our hospital by her neighborhood physician on suspicion of a pelvic tumor. A giant bone cyst (42 ⫻ 31 mm) was found in the load-bearing region of the acetabulum of the right hip joint due to acetabular dysplasia. Fairly good congruity was obserbed, with a center–edge angle of 6°, roof obliquity of 47°, and joint space narrowing on X-ray films (Fig. 1A). These findings led us to a diagnosis of secondary osteoarthritis of the hip after developmental acetabular dysplasia. As the congruity between the acetabulum and the femoral head was good, rotational acetabular osteotomy (RAO) was indicated. However, part of the load-bearing area of the acetabulum appeared irregular on the X-rays. The cortex bone of the ileum was very thin, and the cavity of the cyst occupied a very large area in the trabecular bone on threedimensional computed tomography (3D-CT) scans (Fig. 2). Arthrograms of the hip joint revealed contrast medium flowing into the bone cyst in the acetabulum (Fig. 3A). In view of the substantial risk of serious complications such as collapse of the acetabulum if the operation were conducted in one step, it was decided to perform a two-stage operation. The first operation comprised opening a 15 ⫻ 15 mm fenestration in the lateral wall of the ileum with an incision made laterally on the anterior superior spine and on the anterior part of the iliac wing by lateral position.8 To prevent weakness of tensor fasciae latae, wedge osteotomy was used at the outside crest of the iliac bone when the tensor was detached subperiosteally from the ilium. We thoroughly curetted the soft tissue contents of the bone cyst, and filled the cavity with autogenous bone grafts taken from the ileum mixed with hydroxyapatite granules. During this procedure, care was taken to fill the defect adjacent to the articular surface only with autogenous bone fragments, and the subchondral plate adjacent to the cyst
100
M. Morita et al.: RAO with a giant bone cyst
c
a,b Fig. 1a–c. Clinical course in a patient who underwent a twostage operation. a Preoperative radiograph shows acetabular dysplasia in the right hip joint and a giant 42 ⫻ 31 mm bone cyst in the load-bearing region of the acetabulum. b Radio-
graph 3 months after bone grafting (first operation) shows favorable new bone formation. c Radiograph 5 years after rotational acetabular osteotomy shows disappearance of the cystic structure as a result of bone grafting
Japanese Orthopaedic Association.7 She continued to do well, with favorable fusion of bone verified on X-ray films, and with no signs that the osteoarthrosis was progressing (Fig. 1C). Arthrograms showed neither inflow of contrast medium into the region of the curettaged bone cyst nor irregularities of the articular surface (Fig. 3B). No recurrence of the bone cyst has been detected during a 5-year follow-up period.
Discussion Fig. 2. Preoperative three-dimensional computed tomography (3D-CT) of the right hip joint shows a large bone cyst connecting to the hip joint cavity (frontal view)
wall was not disturbed. The iliac crest and tensor fasciae latae were fixed with wires to the original position of the iliac bone. Partial weight-bearing was permitted 3 weeks after the operation, and full weight-bearing was permitted another 3 weeks later. New bone formation was confirmed by X-rays taken 3 months later (Fig. 1B), and RAO was performed as a second-stage operation. At osteotomy, the cut surface showed new bone formation in the grafted bone with the bone cyst (Fig. 4). Osteotomy was completed without acetabular fracture. In line with the conventional procedure with anterior iliofemoral approach,6 the acetabulum was translocated anterolaterally and fixed with Kirschner wires. The center–edge angle was improved to 40°. The patient was protected against weight-bearing for 6 weeks. Five years after the second operation, she had no complaints regarding her right hip. The hip joint score had improved from 74 to 90 on the scale used by the
RAO, a periacetabular osteotomy that provides satisfactory cover for the femoral head with true articular cartilage in a nearly normal position, has been reported to be useful for patients with no dislocation but with early-stage osteoarthrosis of the hip joint.1,6 However, RAO has been said to be unsuitable for treating acetabular dysplasia accompanied by a giant bone cyst in the acetabulum, because osteotomy involving a bone cyst frequently produces a poor outcome.3 The debate about the indications for RAO for the fragile bone revolves around the expected risks: concurrent osteotomy and bone grafting may cause fracture at the most critical site (the articular surface of the acetabulum close to the cyst), fusion may be delayed after bone grafting, and necrosis of the thin translocated acetabulum may occur. Indeed, Hijikata et al. reported a case of acetabular dysplasia accompanied by a giant bone cyst and osteosclerosis in which total hip replacement was required 3 years after RAO because of severe osteosclerosis, poor fusion, and necrosis of the transferred acetabulum.3 In contrast, Matsumoto et al.4 reported that concurrent treatment comprising curettement, trabecular bone grafting, and RAO yielded good results in a patient with acetabular dysplasia and a 35 ⫻ 20 mm acetabular bone
M. Morita et al.: RAO with a giant bone cyst
a
101
b
Fig. 4. Cut surface of the iliac bone after rotational acetabular osteotomy. The bone cyst was filled with autogenous bone fragments taken from the ileum mixed with hydroxyapatite granules. New bone formation in the grafted bone was observed at the second-stage operation (white arrows)
cyst. They recommended an extended osteotomy allowing rotational translocation of the acetabulum with part of the inner wall of the pelvis, and thorough curettement of the bone cyst, including any lesion present, on the nonrotational side before bone grafting.4 An advantage of our two-stage procedure is that the strength of the bony tissue of the acetabulum can be increased by impacted bone grafting in the first operation, a procedure that may reduce the risk of such complications as fracture of the acetabulum during osteotomy and bone necrosis in the postoperative follow-up period.1 Its disadvantages include the need to
Fig. 3a,b. Arthrograms of the right hip joint. a Before the operation, inflow of contrast agent into the bone cyst from the articular cavity is seen. b Eighteen months after the operation: no flow of contrast medium into the site of the bone cyst is visible, and the congruity of the hip joint appears good
operate twice on the patient and the prolonged period required for treatment, including the time needed for fusion of the grafted bone. In the present case, fragility of the bone and cartilaginous tissue surrounding the cystic lesion was clearly indicated, both because a giant acetabular bone cyst was located close to the articular cavity, with communication between the joint cavity and bone cyst, and because a subchondral bone cyst occupied almost all the weightbearing lesion in the acetabular bone. Eggers et al. reported that bone grafting to the area of cystic change in the acetabulum brought the benefit of pain relief.2 In our case, with secondary osteoarthrosis due to severe acetabular dysplasia, we considered that bone grafting alone would not bring about a complete cure, and that it would need to be combined with acetabular osteotomy to produce good results. Moreover, osteotomy in such a patient could result in significant progression of the osteoarthrosis because of poor bone formation. Indication for this two-stage operation is similar to RAO, but we consider that the important factors are (1) adult age under 50,5 (2) good congruity of the hip joint with mild dysplasia, (3) the size of the bone cyst, and (4) cooperation of the patient. Taking another report4 into consideration, we suppose that the diameter of the periarticular cyst more than 40 mm is considered for indication. Eighteen months after the operation, no communication between the cystic lesion and the articular cavity was observed in our patient, and she retained a favorable congruity of the hip joint at 5 years postoperative. These findings indicate that translocation of the load-bearing surface of the acetabulum by RAO resulted in adequate remodeling of both the bone- and cartilage-like tissues of the transferred acetabulum, and that the two-stage operation is both useful and appropriate for safe treatment of dysplasia of the hip accompanied by a giant acetabular bone cyst. Acknowledgments. The authors are indebted to Dr. R. Timms for correcting the English version of the manuscript.
102
References 1. Azuma H, Taneda H. Rotational acetabular osteotomy in congenital dysplasia of the hip. Int Orthop 1989;13:21–8. 2. Eggers GWN, Evans EB, Blumel J, et al. Cystic change in the iliac acetabulum. J Bone Joint Surg [Am] 1963;45:669–86. 3. Hijikata H, Oguchi S, Machida H, et al. Treatment and prognosis of complication for the rotational acetabular osteotomy. Hip Joint 1991;17:217–20 (in Japanese). 4. Matsumoto T, Kawakita T, Nishimura H, et al. Bone graft for the acetabular bone cyst in rotational acetabular osteotomy. Hip Joint 1991;17:213–6 (in Japanese).
M. Morita et al.: RAO with a giant bone cyst 5. Nakamura S, Ninomiya S, Takatori Y, et al. Long-term outcome of rotational acetabular osteotomy. Acta Orthop Scand 1988;69:259– 65. 6. Ninomiya S, Tagawa H. Rotational acetabular osteotomy for the dysplastic hip. J Bone Joint Surg [Am] 1984;66:430–6. 7. Ogawa R, Imura S. Evaluation chart of hip joint functions. J Jpn Orthop Assoc 1995;69:860–7 (in Japanese and English). 8. Pajarinen J, Hirvensalo E. Two-incision technique for rotational acetabular osteotomy. Acta Orthop Scand 2003;74:133–9.
Rotational acetabular osteotomy for acetabular dysplasia of the hip with a giant acetabular bone cyst: a case report Mitsuhiro Morita1, Harumoto Yamada2, Osamu Hemmi1, and Kyosuke Fujikawa1 1 2
Department of Orthopaedic Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa 359-8513, Japan Fujita Health University, Toyoake, Japan
Abstract In acetabular dysplasia of the hip joint accompanied by a giant acetabular bone cyst, rotational acetabular osteotomy may cause serious complications, such as bone necrosis after surgery or fracture of the fragile acetabulum during the operation. In a patient with this condition, we performed a two-stage operation: first, autogenous bone grafting supplemented with hydroxyapatite filling, then rotational acetabular osteotomy (after new bone formation had been assured). Radiographs and CT scans showed favorable fusion of the grafted bone. Some 18 months after the second operation, arthrograms showed no inflow of contrast medium from the articular cavity into the bone cyst region, although this had been observed before treatment. Thus, an effective remodeling of bony congruency was indicated in the mobile acetabulum 5 years after the second operation. This two-stage operation appears to be useful for correcting acetabular dysplasia accompanied by a giant bone cyst and to carry a reduced risk of serious complications, such as deterioration of the articular surface of the acetabulum or necrosis of the translocated acetabulum. Key words Rotational acetabular osteotomy · Acetabular dysplasia · Hip joint · Bone cyst · Two-stage operation
Introduction In this case report, we present evidence indicating that a two-stage operation for acetabular dysplasia of the hip with a giant bone cyst is useful in that it can make the procedure easier while reducing the risk of serious complications, such as acetabular fracture, deterioration of the articular surface of the acetabulum, and bone necrosis.
Offprint requests to: M. Mortia Received: August 8, 2003 / Accepted: October 15, 2003
Case report A 48-year-old woman complaining of pain in her right hip joint and claudication was referred to our hospital by her neighborhood physician on suspicion of a pelvic tumor. A giant bone cyst (42 ⫻ 31 mm) was found in the load-bearing region of the acetabulum of the right hip joint due to acetabular dysplasia. Fairly good congruity was obserbed, with a center–edge angle of 6°, roof obliquity of 47°, and joint space narrowing on X-ray films (Fig. 1A). These findings led us to a diagnosis of secondary osteoarthritis of the hip after developmental acetabular dysplasia. As the congruity between the acetabulum and the femoral head was good, rotational acetabular osteotomy (RAO) was indicated. However, part of the load-bearing area of the acetabulum appeared irregular on the X-rays. The cortex bone of the ileum was very thin, and the cavity of the cyst occupied a very large area in the trabecular bone on threedimensional computed tomography (3D-CT) scans (Fig. 2). Arthrograms of the hip joint revealed contrast medium flowing into the bone cyst in the acetabulum (Fig. 3A). In view of the substantial risk of serious complications such as collapse of the acetabulum if the operation were conducted in one step, it was decided to perform a two-stage operation. The first operation comprised opening a 15 ⫻ 15 mm fenestration in the lateral wall of the ileum with an incision made laterally on the anterior superior spine and on the anterior part of the iliac wing by lateral position.8 To prevent weakness of tensor fasciae latae, wedge osteotomy was used at the outside crest of the iliac bone when the tensor was detached subperiosteally from the ilium. We thoroughly curetted the soft tissue contents of the bone cyst, and filled the cavity with autogenous bone grafts taken from the ileum mixed with hydroxyapatite granules. During this procedure, care was taken to fill the defect adjacent to the articular surface only with autogenous bone fragments, and the subchondral plate adjacent to the cyst
100
M. Morita et al.: RAO with a giant bone cyst
c
a,b Fig. 1a–c. Clinical course in a patient who underwent a twostage operation. a Preoperative radiograph shows acetabular dysplasia in the right hip joint and a giant 42 ⫻ 31 mm bone cyst in the load-bearing region of the acetabulum. b Radio-
graph 3 months after bone grafting (first operation) shows favorable new bone formation. c Radiograph 5 years after rotational acetabular osteotomy shows disappearance of the cystic structure as a result of bone grafting
Japanese Orthopaedic Association.7 She continued to do well, with favorable fusion of bone verified on X-ray films, and with no signs that the osteoarthrosis was progressing (Fig. 1C). Arthrograms showed neither inflow of contrast medium into the region of the curettaged bone cyst nor irregularities of the articular surface (Fig. 3B). No recurrence of the bone cyst has been detected during a 5-year follow-up period.
Discussion Fig. 2. Preoperative three-dimensional computed tomography (3D-CT) of the right hip joint shows a large bone cyst connecting to the hip joint cavity (frontal view)
wall was not disturbed. The iliac crest and tensor fasciae latae were fixed with wires to the original position of the iliac bone. Partial weight-bearing was permitted 3 weeks after the operation, and full weight-bearing was permitted another 3 weeks later. New bone formation was confirmed by X-rays taken 3 months later (Fig. 1B), and RAO was performed as a second-stage operation. At osteotomy, the cut surface showed new bone formation in the grafted bone with the bone cyst (Fig. 4). Osteotomy was completed without acetabular fracture. In line with the conventional procedure with anterior iliofemoral approach,6 the acetabulum was translocated anterolaterally and fixed with Kirschner wires. The center–edge angle was improved to 40°. The patient was protected against weight-bearing for 6 weeks. Five years after the second operation, she had no complaints regarding her right hip. The hip joint score had improved from 74 to 90 on the scale used by the
RAO, a periacetabular osteotomy that provides satisfactory cover for the femoral head with true articular cartilage in a nearly normal position, has been reported to be useful for patients with no dislocation but with early-stage osteoarthrosis of the hip joint.1,6 However, RAO has been said to be unsuitable for treating acetabular dysplasia accompanied by a giant bone cyst in the acetabulum, because osteotomy involving a bone cyst frequently produces a poor outcome.3 The debate about the indications for RAO for the fragile bone revolves around the expected risks: concurrent osteotomy and bone grafting may cause fracture at the most critical site (the articular surface of the acetabulum close to the cyst), fusion may be delayed after bone grafting, and necrosis of the thin translocated acetabulum may occur. Indeed, Hijikata et al. reported a case of acetabular dysplasia accompanied by a giant bone cyst and osteosclerosis in which total hip replacement was required 3 years after RAO because of severe osteosclerosis, poor fusion, and necrosis of the transferred acetabulum.3 In contrast, Matsumoto et al.4 reported that concurrent treatment comprising curettement, trabecular bone grafting, and RAO yielded good results in a patient with acetabular dysplasia and a 35 ⫻ 20 mm acetabular bone
M. Morita et al.: RAO with a giant bone cyst
a
101
b
Fig. 4. Cut surface of the iliac bone after rotational acetabular osteotomy. The bone cyst was filled with autogenous bone fragments taken from the ileum mixed with hydroxyapatite granules. New bone formation in the grafted bone was observed at the second-stage operation (white arrows)
cyst. They recommended an extended osteotomy allowing rotational translocation of the acetabulum with part of the inner wall of the pelvis, and thorough curettement of the bone cyst, including any lesion present, on the nonrotational side before bone grafting.4 An advantage of our two-stage procedure is that the strength of the bony tissue of the acetabulum can be increased by impacted bone grafting in the first operation, a procedure that may reduce the risk of such complications as fracture of the acetabulum during osteotomy and bone necrosis in the postoperative follow-up period.1 Its disadvantages include the need to
Fig. 3a,b. Arthrograms of the right hip joint. a Before the operation, inflow of contrast agent into the bone cyst from the articular cavity is seen. b Eighteen months after the operation: no flow of contrast medium into the site of the bone cyst is visible, and the congruity of the hip joint appears good
operate twice on the patient and the prolonged period required for treatment, including the time needed for fusion of the grafted bone. In the present case, fragility of the bone and cartilaginous tissue surrounding the cystic lesion was clearly indicated, both because a giant acetabular bone cyst was located close to the articular cavity, with communication between the joint cavity and bone cyst, and because a subchondral bone cyst occupied almost all the weightbearing lesion in the acetabular bone. Eggers et al. reported that bone grafting to the area of cystic change in the acetabulum brought the benefit of pain relief.2 In our case, with secondary osteoarthrosis due to severe acetabular dysplasia, we considered that bone grafting alone would not bring about a complete cure, and that it would need to be combined with acetabular osteotomy to produce good results. Moreover, osteotomy in such a patient could result in significant progression of the osteoarthrosis because of poor bone formation. Indication for this two-stage operation is similar to RAO, but we consider that the important factors are (1) adult age under 50,5 (2) good congruity of the hip joint with mild dysplasia, (3) the size of the bone cyst, and (4) cooperation of the patient. Taking another report4 into consideration, we suppose that the diameter of the periarticular cyst more than 40 mm is considered for indication. Eighteen months after the operation, no communication between the cystic lesion and the articular cavity was observed in our patient, and she retained a favorable congruity of the hip joint at 5 years postoperative. These findings indicate that translocation of the load-bearing surface of the acetabulum by RAO resulted in adequate remodeling of both the bone- and cartilage-like tissues of the transferred acetabulum, and that the two-stage operation is both useful and appropriate for safe treatment of dysplasia of the hip accompanied by a giant acetabular bone cyst. Acknowledgments. The authors are indebted to Dr. R. Timms for correcting the English version of the manuscript.
102
References 1. Azuma H, Taneda H. Rotational acetabular osteotomy in congenital dysplasia of the hip. Int Orthop 1989;13:21–8. 2. Eggers GWN, Evans EB, Blumel J, et al. Cystic change in the iliac acetabulum. J Bone Joint Surg [Am] 1963;45:669–86. 3. Hijikata H, Oguchi S, Machida H, et al. Treatment and prognosis of complication for the rotational acetabular osteotomy. Hip Joint 1991;17:217–20 (in Japanese). 4. Matsumoto T, Kawakita T, Nishimura H, et al. Bone graft for the acetabular bone cyst in rotational acetabular osteotomy. Hip Joint 1991;17:213–6 (in Japanese).
M. Morita et al.: RAO with a giant bone cyst 5. Nakamura S, Ninomiya S, Takatori Y, et al. Long-term outcome of rotational acetabular osteotomy. Acta Orthop Scand 1988;69:259– 65. 6. Ninomiya S, Tagawa H. Rotational acetabular osteotomy for the dysplastic hip. J Bone Joint Surg [Am] 1984;66:430–6. 7. Ogawa R, Imura S. Evaluation chart of hip joint functions. J Jpn Orthop Assoc 1995;69:860–7 (in Japanese and English). 8. Pajarinen J, Hirvensalo E. Two-incision technique for rotational acetabular osteotomy. Acta Orthop Scand 2003;74:133–9.