Eur J Orthop Surg Traumatol DOI 10.1007/s00590-013-1379-7
ORIGINAL ARTICLE
Risk of acetabular protrusion is low in rheumatoid arthritis patients treated with bipolar hemiarthroplasty for displaced femoral neck fractures without rheumatoid change in hip joints Yu Mori • Naoko Mori • Taketo Mori • Satoshi Nakamura • Masato Ishizuka • Tokuhisa Sano • Eiji Itoi
Received: 29 July 2013 / Accepted: 30 October 2013 Ó Springer-Verlag France 2013
Abstract Objectives The aim of this study was to analyze the radiological outcomes of bipolar hemiarthroplasty after displaced femoral neck fractures of non-arthritic hip joints in rheumatoid arthritis patients. Methods We retrospectively investigated 25 hip joints in 23 rheumatoid arthritis patients who underwent bipolar hemiarthroplasty for displaced femoral neck fracture of non-arthritic hip joints. All patients were female with an average age of 69.8 years (range 51–83 years). Mean follow-up duration was 8.4 years (range 5–12 years). Radiographs taken immediately, 1 year after surgery and most recently, were collected for each case. Radiographic measurement of the migration distance of the outer-head prosthesis in the direction of vertical, horizontal and medial to Ko¨hler’s line was undertaken at 1 year after surgery and most recently. Results No patients had hip-related pain after surgery. No case indicated apparent central migration and [3-mm migration of the hemisphere in each direction. There was
Y. Mori (&) E. Itoi Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo machi, Aobaku, Sendai, Miyagi 980-8574, Japan e-mail: [email protected] N. Mori Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, Miyagi, Japan T. Mori Mori Orthopaedic Clinic, Miyagi, Japan S. Nakamura M. Ishizuka T. Sano Department of Orthopaedic Surgery, Tohoku Koseinenkin Hospital, Miyagi, Japan
no significant change in migration distance between evaluation at 1 year after surgery and most recently. Conclusions We conclude that risk of acetabular protrusion appears to be low in patients of rheumatoid arthritis treated with bipolar hemiarthroplasty for displaced femoral neck fractures of non-arthritic hip joints in the medium term. Keywords Rheumatoid arthritis Femoral neck fracture Bipolar hemiarthroplasty Surgical treatment Acetabular protrusion
Introduction In rheumatoid arthritis patients, total hip arthroplasty is generally undertaken for the surgical treatment for arthritic hip lesions. Bipolar hemiarthroplasty is performed rarely for hips with rheumatoid arthritis because central migration of the prosthesis and acetabular protrusion can occur and the treatment outcomes have been poor [1, 2]. By contrast, hemiarthroplasty is commonly performed as the treatment for displaced femoral neck fracture in non-rheumatoid arthritis patients [3]. Some randomized trials and metaanalyses have concluded that total hip arthroplasty provided better function than hemiarthroplasty after displaced femoral neck fractures [4–6]. However, these conclusions were based on relatively small study populations and shortterm follow-up. Another randomized trial reported that total hip arthroplasty treatment had higher intraoperative blood loss, longer operating time and more late hip dislocation [7]. For these reasons, some orthopedic surgeons prefer bipolar hemiarthroplasty over total hip arthroplasty in the treatment of this injury. The alternative treatments for intracapsular fractures of non-arthritic hips in rheumatoid arthritis patients are
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controversial, and few studies have described the progression of prosthesis migration after monopolar hemiarthroplasty in displaced femoral neck fractures in rheumatoid arthritis patients without advanced hip disease [8, 9]. In contrast, we reported previously the short- and mediumterm results of bipolar hemiarthroplasty of hip fracture of non-arthritic joints, and no patients had apparent central migration of the outer-head prosthesis [10]. These reports were based on the outcome of a small patient group, and there are no definitive reports that have optimized the treatment for femoral neck fractures in non-arthritic joints. Therefore, the best treatment for displaced femoral neck fractures of non-arthritic hip joints in rheumatoid arthritis remains controversial. This retrospective study investigated the radiological results of bipolar hemiarthroplasty of displaced hip fractures of non-arthritic joints. We precisely assessed the vertical and horizontal migrations of the prosthetic head and the distance between Ko¨hler’s line and the prosthetic head 1 and C5 years after surgery in patients with intracapsular fractures of the non-arthritic hip. We hypothesized that the radiological outcomes of bipolar hemiarthroplasty did not indicate apparent central migration in the midterm or long term after surgery in patients with displaced femoral neck fractures without advanced arthritic changes.
respectively [12]. Each patient was assessed at last followup. Radiographic measurement Radiographs were taken immediately and 1 year postoperatively and most recently for each patient; three measurements were taken on each radiograph. The progression of outer-head migration was defined as the relationship between the outer head and Ko¨hler’s line, the horizontal distance between the tear drop and center of the outer head or the vertical distance between the tear drop line and center of the outer head, as described previously [13]. Graphic interpretation of each measurement is shown in Fig. 1. Each measurement was taken by two readers, one orthopedic surgeon and one radiologist, and the averaged results were recorded. For comparison of migration data at 1 year after surgery and most recently, an independent sample Mann–Whitney U test was applied. JMP version 9 (SAS, Carry, NC, USA) was used for statistical analysis.
Results In the same term, five cases of total hip arthroplasty had been performed for displaced hip fracture of arthritic hip
Patients and methods The ethics committee of our hospital approved the study, and all patients provided written informed consent. We retrospectively investigated 25 hips in 23 patients treated at Tohoku Koseinenkin Hospital from 1990 to 2007. We excluded the patients of bedridden or barely mobile bed to wheel chair or significant senile dementia. We did not follow up three cases because of mortality or other reasons. All patients were female, with a mean age of 69.8 (range 51–83) years. All patients were fulfilled American College of Rheumatology criteria for rheumatoid arthritis [11]. The duration of rheumatoid arthritis was 5–38 (mean 15.7) years. Sixteen cases had maintenance dosage of glucocorticoid treatment. Fourteen patients were treated with methotrexate, and 12 patients were treated with oral DMARDs. Biological drugs were not applied for these patients. All fractures were classified as Garden type III or IV. We performed cemented bipolar hemiarthroplasty for intracapsular fracture of non-arthritic hips. The observation period was from 5 to 12 (average 8.4) years. Bipolar hemiarthroplasty was performed with Charnley cemented prosthesis or C-stem cemented prosthesis and a self-centering cup (DePuy, UK). Clinical assessment was performed using Merle d’Aubigne hip score, with a maximum score of six points for pain, mobility and ability to walk,
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Fig. 1 Graphic depiction of the radiographic measurement procedure. Line 1 indicates the vertical distance between the tear drop line and the center of the outer-head prosthesis. Line 2 indicates the horizontal distance between the tear drop and the center of the outerhead prosthesis. Line 3 indicates the minimum distance between Ko¨hler’s line and the outer-head prosthesis. A more than 3-mm migration was defined as significant, as described previously [4]
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joints by rheumatoid arthritis. In bipolar hemiarthroplasty treatment group, five of 25 cases indicated a radiolucent line around prosthesis, but no apparent radiographic evidence of loosening and stem sinking. Merle d’Aubigne hip score at last follow-up was 17.1, pain was 5.7 ± 0.46, mobility was 5.8 ± 0.41, and ability to walk was 5.6 ± 0.5. The radiographic measurements of vertical migration of the outer head are shown in Fig. 2. Average measurement at 1 year after surgery was 0.92 mm (95 % CI 0.75–1.09). The mean of the most recent measurement was 1.13 mm (95 % CI 0.93–1.33). No case indicated a [3-mm migration to the proximal side. There was no significant difference in migration distance between 1 year postoperatively and the most recent follow-up evaluation (p = 0.12). Evaluation of the horizontal distance is shown in Fig. 3. The average change in horizontal migration between immediately and 1 year postoperatively was 0.93 mm (95 % CI 0.71–1.16). The average change between
immediately postoperatively and the most recent radiograph was 1.18 mm (95 % CI 0.95–1.41). None of the 25 cases indicated a horizontal migration C3 mm. There was no significant change between evaluation at 1 year after surgery and the most recent radiograph (p = 0.07). Radiographic evaluation of medial migration of the outer-head prosthesis is shown in Fig. 4. One year after surgery, outer diameter of the bipolar head to Ko¨hler’s line averaged 0.85 mm (95 % CI 0.64–1.09). The most recent evaluation averaged 1.08 mm (95 % CI 0.89–1.29). No case had [3-mm migration or progressive protrusion. There was no significant difference between evaluation at 1 year after surgery and the most recent radiograph (p = 0.07), with regard to vertical and horizontal migrations. One case showed a 2-mm migration of the outer-head prosthesis both in the vertical direction and to Ko¨hler’s line. A representative case of a 68-year-old female is shown in Fig. 5. In this case, 1.5-mm proximal migration and medial migration to Ko¨hler’s line were observed at 1 year after surgery. On the most recent radiograph, 7 years after surgery, proximal migration and migration of the outerhead prosthesis medial to Ko¨hler’s line were measured as 2 mm and did not significantly progress during the 6 years, following the evaluation at 1 year postoperatively. There was no apparent loosening. The radiographs showed sclerotic changes in the subchondral bone of the acetabulum, but this patient had no hip pain.
Discussion Fig. 2 Vertical migration results. Vertical migration at 1 year after the procedure: mean (SD): 0.92 (0.41), 95 % CI 0.75–1.09. Vertical migration immediately after surgery and at most recent evaluation: mean (SD): 1.13 (0.49), 95 % CI 0.93–1.33
Patients with rheumatoid arthritis have an increased risk of hip fracture compared to healthy individuals without rheumatoid arthritis [14–20]. The incidence of hip fracture in rheumatoid arthritis patients was reported to be 7.4 % of
Fig. 3 Horizontal migration results. Horizontal migration at 1 year after the procedure: mean (SD) 0.93 (0.56), 95 % CI 0.71–1.16. Horizontal migration immediately after surgery and at most recent evaluation: mean (SD) 1.18 (0.56), 95 % CI 0.95–1.41
Fig. 4 Medial migration to Ko¨hler’s line results. Medial migration to Ko¨hler’s line at 1 year after the procedure: mean (SD): 0.85 (0.52), 95 % CI 0.64–1.09. Medial migration to Ko¨hler’s line immediately after the procedure and at most recent evaluation: mean (SD) 1.08 (0.45), 95 % CI 0.89–1.29
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Fig. 5 Radiographs of a representative case. This patient was a 68-year-old female. Hemiarthroplasty with C-stem was performed for a displaced femoral neck fracture of a non-arthritic hip (a). One year after surgery, a 1.5-mm proximal migration and medial migration to Ko¨hler’s line were observed, but there were no signs of sinking and
loosening of the femoral prosthesis (b). Seven years after the procedure, central migration of the outer-head prosthesis had not progressed during the 6 years, following the evaluation at 1 year postoperatively. At this time, there were no signs of loosening and sinking of the femoral prosthesis (c)
388 cases followed up over a 25-year period [15]. In Japan, it has been reported that 86 % of elderly rheumatoid arthritis patients have a high risk of hip fracture [21], and there has been an increase in the number of hip fractures in recent years [22]. With regard to the treatment for fractures of arthritic hip joints in rheumatoid arthritis, hemiarthroplasty has been reported to be unsatisfactory due to central migration [8, 9], and total hip arthroplasty is generally performed for the surgical treatment for arthritic hip lesions. In contrast, there are no definitive data on the treatment for intracapsular fractures in rheumatoid arthritis patients without arthritic hip lesions, and surgical treatment with bipolar hemiarthroplasty or total hip arthroplasty is controversial. In this study, we reported the results of radiographic measurement after cemented bipolar hemiarthroplasty for intracapsular fracture of non-arthritic hips in 25 hips of 23 patients with rheumatoid arthritis. The results of bipolar hemiarthroplasty for non-arthritic hips were satisfactory in the medium term. No case indicated a [3-mm severe migration proximal, horizontal or medial to Ko¨hler’s line. There was no significant change in the migration distance between 1 year postoperatively and the most recent radiographs, but this study is medium-term follow-up and it might be likely trending significant change in component position in long term. Only one case showed a 1.7-mm migration proximal and medial to Ko¨hler’s line at 1 year after surgery and did not show significant progression during 6-year follow-up. Our data support bipolar hemiarthroplasty for non-arthritic displaced hip fracture. Few
reports of medium-term results of bipolar arthroplasty for proximal femoral neck fracture of non-arthritic hips in rheumatoid arthritis patients are available, and all describe no apparent central migration in radiographic measurement and no hip symptoms after surgery [10, 23, 24]. Total hip arthroplasty should be performed for displaced femoral neck fractures in hips with apparent rheumatoid changes and active synovitis. This study had a number of limitations. The first is the small number of patients treated with bipolar hemiarthroplasty. In our series, bipolar hemiarthroplasty was used for displaced hip fractures in non-arthritic hip joints with radiographic Larsen grade 0, while total hip arthroplasty was performed in displaced hip fractures with rheumatoid lesions. Therefore, the number of bipolar hemiarthroplasty cases was limited. We investigated prosthesis migration radiographically and did not evaluate clinical scores, physical findings or rheumatoid arthritis disease activity. We conclude that in femoral neck fractures in rheumatoid arthritis patients without arthritic changes, the results of bipolar hemiarthroplasty are comparable to those of total hip arthroplasty, and compared with total hip arthroplasty, this technique is less invasiveness and less expensive. Hemiarthroplasty thus seems to be indicated for nonarthritic hip fractures in patients with rheumatoid arthritis, but this study has small sample size, likely underpowered and medium-term follow-up, and it remains unclear whether the outer-head prosthesis continues to protrude in long term, so a larger number of cases and longer follow-up are required to determine the optimal treatment.
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None.
References
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1. McConville OR, Bowman AJ Jr, Kilfoyle RM, McConville JF, Mayo RA (1990) Bipolar hemiarthroplasty in degenerative arthritis of the hip 100 consecutive cases. Clin Orthop Relat Res 251:67–74 2. Vazquez-Vela G, Vazquez-Vela E, Garcia Dobarganes F (1990) The Bateman bipolar prosthesis in osteoarthritis and rheumatoid arthritis. A review of 400 cases. Clin Orthop Relat Res 251:82–86 3. Bhandari M, Devereaux PJ, Tornetta P III, Swiontkowski MF, Berry DJ, Haidukewych G et al (2005) Operative management of displaced femoral neck fractures in elderly patients. An international survey. J Bone Joint Surg Am 87(9):2122–2130 4. Keating JF, Grant A, Masson M, Scott NW, Forbes JF (2006) Randomized comparison of reduction and fixation, bipolar hemiarthroplasty, and total hip arthroplasty. Treatment of displaced intracapsular hip fractures in healthy older patients. J Bone Joint Surg Am 88(2):249–260 5. Blomfeldt R, Tornkvist H, Eriksson K, Soderqvist A, Ponzer S, Tidermark J (2007) A randomised controlled trial comparing bipolar hemiarthroplasty with total hip replacement for displaced intracapsular fractures of the femoral neck in elderly patients. J Bone Joint Surg Br 89(2):160–165 6. Baker RP, Squires B, Gargan MF, Bannister GC (2006) Total hip arthroplasty and hemiarthroplasty in mobile, independent patients with a displaced intracapsular fracture of the femoral neck. A randomized, controlled trial. J Bone Joint Surg Am 88(12):2583–2589 7. van den Bekerom MP, Hilverdink EF, Sierevelt IN, Reuling EM, Schnater JM, Bonke H et al (2010) A comparison of hemiarthroplasty with total hip replacement for displaced intracapsular fracture of the femoral neck: a randomised controlled multicentre trial in patients aged 70 years and over. J Bone Joint Surg Br 92(10):1422–1428 8. Bogoch E, Ouellette G, Hastings D (1991) Failure of internal fixation of displaced femoral neck fractures in rheumatoid patients. J Bone Joint Surg Br 73(1):7–10 9. Delamarter R, Moreland JR (1987) Treatment of acute femoral neck fractures with total hip arthroplasty. Clin Orthop Relat Res 218:68–74 10. Sano T, Mori T, Yamada N, Yoshida S, Yang S, Watanabe S et al (2003) Bipolar hemiarthroplasty for femoral neck fractures in rheumatoid arthritis (in Japanese). Jpn J Rheum Joint Surg 22(2):123–130 11. Arnett FC, Edworthy SM, Bloch DA, McShane DJ, Fries JF, Cooper NS, Healey LA, Kaplan SR, Liang MH, Luthra HS et al
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(1998) The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum 31(3):315–324 Merle D’aubigne R, Postel M (1954) Functional results of hip arthroplasty with acrylic prosthesis. J Bone Joint Surg Am 36(3):451–475 Gates HS III, Poletti SC, Callaghan JJ, McCollum DE (1989) Radiographic measurements in protrusio acetabuli. J Arthroplasty 4(4):347–351 Cooper C, Coupland C, Mitchell M (1995) Rheumatoid arthritis, corticosteroid therapy and hip fracture. Ann Rheum Dis 54(1):49–52 Hooyman JR, Melton LJ III, Nelson AM, O’Fallon WM, Riggs BL (1984) Fractures after rheumatoid arthritis. A populationbased study. Arthritis Rheum 27(12):1353–1361 Huusko TM, Korpela M, Karppi P, Avikainen V, Kautiainen H, Sulkava R (2001) Threefold increased risk of hip fractures with rheumatoid arthritis in Central Finland. Ann Rheum Dis 60(5):521–522 Kim SY, Schneeweiss S, Liu J, Daniel GW, Chang CL, Garneau K et al (2010) Risk of osteoporotic fracture in a large populationbased cohort of patients with rheumatoid arthritis. Arthritis Res Ther 12(4):R154 Orstavik RE, Haugeberg G, Uhlig T, Mowinckel P, Falch JA, Halse JI et al (2004) Self reported non-vertebral fractures in rheumatoid arthritis and population based controls: incidence and relationship with bone mineral density and clinical variables. Ann Rheum Dis 63(2):177–182 van Staa TP, Geusens P, Bijlsma JW, Leufkens HG, Cooper C (2006) Clinical assessment of the long-term risk of fracture in patients with rheumatoid arthritis. Arthritis Rheum 54(10):3104–3112 Wright NC, Lisse JR, Walitt BT, Eaton CB, Chen Z (2011) Arthritis increases the risk for fractures–results from the Women’s Health Initiative. J Rheumatol 38(8):1680–1688 Furuya T, Hosoi T, Saito S, Inoue E, Taniguchi A, Momohara S et al (2011) Fracture risk assessment and osteoporosis treatment disparities in 3,970 Japanese patients with rheumatoid arthritis. Clin Rheumatol 30(8):1105–1111 Hagino H, Sakamoto K, Harada A, Nakamura T, Mutoh Y, Mori S et al (2010) Nationwide one-decade survey of hip fractures in Japan. J Orthop Sci 15(6):737–745 Arai K, Hoshino M, Murai T, Fujisawa J, Kondo N, Netsu T et al (2007) Proximal femoral fracture in patients with rheumatoid arthritis. Mod Rheumatol 17(4):317–321 Kageyama Y, Miyamoto S, Ozeki T, Shimazu M, Hiyoshi M, Suzuki M, Miura S et al (2000) A study of bipolar-type hip arthroplasty for rheumatoid arthritis (in Japanese). Jpn J of Clin Ortop 35(9):1027–1029
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ORIGINAL ARTICLE
Risk of acetabular protrusion is low in rheumatoid arthritis patients treated with bipolar hemiarthroplasty for displaced femoral neck fractures without rheumatoid change in hip joints Yu Mori • Naoko Mori • Taketo Mori • Satoshi Nakamura • Masato Ishizuka • Tokuhisa Sano • Eiji Itoi
Received: 29 July 2013 / Accepted: 30 October 2013 Ó Springer-Verlag France 2013
Abstract Objectives The aim of this study was to analyze the radiological outcomes of bipolar hemiarthroplasty after displaced femoral neck fractures of non-arthritic hip joints in rheumatoid arthritis patients. Methods We retrospectively investigated 25 hip joints in 23 rheumatoid arthritis patients who underwent bipolar hemiarthroplasty for displaced femoral neck fracture of non-arthritic hip joints. All patients were female with an average age of 69.8 years (range 51–83 years). Mean follow-up duration was 8.4 years (range 5–12 years). Radiographs taken immediately, 1 year after surgery and most recently, were collected for each case. Radiographic measurement of the migration distance of the outer-head prosthesis in the direction of vertical, horizontal and medial to Ko¨hler’s line was undertaken at 1 year after surgery and most recently. Results No patients had hip-related pain after surgery. No case indicated apparent central migration and [3-mm migration of the hemisphere in each direction. There was
Y. Mori (&) E. Itoi Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo machi, Aobaku, Sendai, Miyagi 980-8574, Japan e-mail: [email protected] N. Mori Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, Miyagi, Japan T. Mori Mori Orthopaedic Clinic, Miyagi, Japan S. Nakamura M. Ishizuka T. Sano Department of Orthopaedic Surgery, Tohoku Koseinenkin Hospital, Miyagi, Japan
no significant change in migration distance between evaluation at 1 year after surgery and most recently. Conclusions We conclude that risk of acetabular protrusion appears to be low in patients of rheumatoid arthritis treated with bipolar hemiarthroplasty for displaced femoral neck fractures of non-arthritic hip joints in the medium term. Keywords Rheumatoid arthritis Femoral neck fracture Bipolar hemiarthroplasty Surgical treatment Acetabular protrusion
Introduction In rheumatoid arthritis patients, total hip arthroplasty is generally undertaken for the surgical treatment for arthritic hip lesions. Bipolar hemiarthroplasty is performed rarely for hips with rheumatoid arthritis because central migration of the prosthesis and acetabular protrusion can occur and the treatment outcomes have been poor [1, 2]. By contrast, hemiarthroplasty is commonly performed as the treatment for displaced femoral neck fracture in non-rheumatoid arthritis patients [3]. Some randomized trials and metaanalyses have concluded that total hip arthroplasty provided better function than hemiarthroplasty after displaced femoral neck fractures [4–6]. However, these conclusions were based on relatively small study populations and shortterm follow-up. Another randomized trial reported that total hip arthroplasty treatment had higher intraoperative blood loss, longer operating time and more late hip dislocation [7]. For these reasons, some orthopedic surgeons prefer bipolar hemiarthroplasty over total hip arthroplasty in the treatment of this injury. The alternative treatments for intracapsular fractures of non-arthritic hips in rheumatoid arthritis patients are
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controversial, and few studies have described the progression of prosthesis migration after monopolar hemiarthroplasty in displaced femoral neck fractures in rheumatoid arthritis patients without advanced hip disease [8, 9]. In contrast, we reported previously the short- and mediumterm results of bipolar hemiarthroplasty of hip fracture of non-arthritic joints, and no patients had apparent central migration of the outer-head prosthesis [10]. These reports were based on the outcome of a small patient group, and there are no definitive reports that have optimized the treatment for femoral neck fractures in non-arthritic joints. Therefore, the best treatment for displaced femoral neck fractures of non-arthritic hip joints in rheumatoid arthritis remains controversial. This retrospective study investigated the radiological results of bipolar hemiarthroplasty of displaced hip fractures of non-arthritic joints. We precisely assessed the vertical and horizontal migrations of the prosthetic head and the distance between Ko¨hler’s line and the prosthetic head 1 and C5 years after surgery in patients with intracapsular fractures of the non-arthritic hip. We hypothesized that the radiological outcomes of bipolar hemiarthroplasty did not indicate apparent central migration in the midterm or long term after surgery in patients with displaced femoral neck fractures without advanced arthritic changes.
respectively [12]. Each patient was assessed at last followup. Radiographic measurement Radiographs were taken immediately and 1 year postoperatively and most recently for each patient; three measurements were taken on each radiograph. The progression of outer-head migration was defined as the relationship between the outer head and Ko¨hler’s line, the horizontal distance between the tear drop and center of the outer head or the vertical distance between the tear drop line and center of the outer head, as described previously [13]. Graphic interpretation of each measurement is shown in Fig. 1. Each measurement was taken by two readers, one orthopedic surgeon and one radiologist, and the averaged results were recorded. For comparison of migration data at 1 year after surgery and most recently, an independent sample Mann–Whitney U test was applied. JMP version 9 (SAS, Carry, NC, USA) was used for statistical analysis.
Results In the same term, five cases of total hip arthroplasty had been performed for displaced hip fracture of arthritic hip
Patients and methods The ethics committee of our hospital approved the study, and all patients provided written informed consent. We retrospectively investigated 25 hips in 23 patients treated at Tohoku Koseinenkin Hospital from 1990 to 2007. We excluded the patients of bedridden or barely mobile bed to wheel chair or significant senile dementia. We did not follow up three cases because of mortality or other reasons. All patients were female, with a mean age of 69.8 (range 51–83) years. All patients were fulfilled American College of Rheumatology criteria for rheumatoid arthritis [11]. The duration of rheumatoid arthritis was 5–38 (mean 15.7) years. Sixteen cases had maintenance dosage of glucocorticoid treatment. Fourteen patients were treated with methotrexate, and 12 patients were treated with oral DMARDs. Biological drugs were not applied for these patients. All fractures were classified as Garden type III or IV. We performed cemented bipolar hemiarthroplasty for intracapsular fracture of non-arthritic hips. The observation period was from 5 to 12 (average 8.4) years. Bipolar hemiarthroplasty was performed with Charnley cemented prosthesis or C-stem cemented prosthesis and a self-centering cup (DePuy, UK). Clinical assessment was performed using Merle d’Aubigne hip score, with a maximum score of six points for pain, mobility and ability to walk,
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Fig. 1 Graphic depiction of the radiographic measurement procedure. Line 1 indicates the vertical distance between the tear drop line and the center of the outer-head prosthesis. Line 2 indicates the horizontal distance between the tear drop and the center of the outerhead prosthesis. Line 3 indicates the minimum distance between Ko¨hler’s line and the outer-head prosthesis. A more than 3-mm migration was defined as significant, as described previously [4]
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joints by rheumatoid arthritis. In bipolar hemiarthroplasty treatment group, five of 25 cases indicated a radiolucent line around prosthesis, but no apparent radiographic evidence of loosening and stem sinking. Merle d’Aubigne hip score at last follow-up was 17.1, pain was 5.7 ± 0.46, mobility was 5.8 ± 0.41, and ability to walk was 5.6 ± 0.5. The radiographic measurements of vertical migration of the outer head are shown in Fig. 2. Average measurement at 1 year after surgery was 0.92 mm (95 % CI 0.75–1.09). The mean of the most recent measurement was 1.13 mm (95 % CI 0.93–1.33). No case indicated a [3-mm migration to the proximal side. There was no significant difference in migration distance between 1 year postoperatively and the most recent follow-up evaluation (p = 0.12). Evaluation of the horizontal distance is shown in Fig. 3. The average change in horizontal migration between immediately and 1 year postoperatively was 0.93 mm (95 % CI 0.71–1.16). The average change between
immediately postoperatively and the most recent radiograph was 1.18 mm (95 % CI 0.95–1.41). None of the 25 cases indicated a horizontal migration C3 mm. There was no significant change between evaluation at 1 year after surgery and the most recent radiograph (p = 0.07). Radiographic evaluation of medial migration of the outer-head prosthesis is shown in Fig. 4. One year after surgery, outer diameter of the bipolar head to Ko¨hler’s line averaged 0.85 mm (95 % CI 0.64–1.09). The most recent evaluation averaged 1.08 mm (95 % CI 0.89–1.29). No case had [3-mm migration or progressive protrusion. There was no significant difference between evaluation at 1 year after surgery and the most recent radiograph (p = 0.07), with regard to vertical and horizontal migrations. One case showed a 2-mm migration of the outer-head prosthesis both in the vertical direction and to Ko¨hler’s line. A representative case of a 68-year-old female is shown in Fig. 5. In this case, 1.5-mm proximal migration and medial migration to Ko¨hler’s line were observed at 1 year after surgery. On the most recent radiograph, 7 years after surgery, proximal migration and migration of the outerhead prosthesis medial to Ko¨hler’s line were measured as 2 mm and did not significantly progress during the 6 years, following the evaluation at 1 year postoperatively. There was no apparent loosening. The radiographs showed sclerotic changes in the subchondral bone of the acetabulum, but this patient had no hip pain.
Discussion Fig. 2 Vertical migration results. Vertical migration at 1 year after the procedure: mean (SD): 0.92 (0.41), 95 % CI 0.75–1.09. Vertical migration immediately after surgery and at most recent evaluation: mean (SD): 1.13 (0.49), 95 % CI 0.93–1.33
Patients with rheumatoid arthritis have an increased risk of hip fracture compared to healthy individuals without rheumatoid arthritis [14–20]. The incidence of hip fracture in rheumatoid arthritis patients was reported to be 7.4 % of
Fig. 3 Horizontal migration results. Horizontal migration at 1 year after the procedure: mean (SD) 0.93 (0.56), 95 % CI 0.71–1.16. Horizontal migration immediately after surgery and at most recent evaluation: mean (SD) 1.18 (0.56), 95 % CI 0.95–1.41
Fig. 4 Medial migration to Ko¨hler’s line results. Medial migration to Ko¨hler’s line at 1 year after the procedure: mean (SD): 0.85 (0.52), 95 % CI 0.64–1.09. Medial migration to Ko¨hler’s line immediately after the procedure and at most recent evaluation: mean (SD) 1.08 (0.45), 95 % CI 0.89–1.29
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Fig. 5 Radiographs of a representative case. This patient was a 68-year-old female. Hemiarthroplasty with C-stem was performed for a displaced femoral neck fracture of a non-arthritic hip (a). One year after surgery, a 1.5-mm proximal migration and medial migration to Ko¨hler’s line were observed, but there were no signs of sinking and
loosening of the femoral prosthesis (b). Seven years after the procedure, central migration of the outer-head prosthesis had not progressed during the 6 years, following the evaluation at 1 year postoperatively. At this time, there were no signs of loosening and sinking of the femoral prosthesis (c)
388 cases followed up over a 25-year period [15]. In Japan, it has been reported that 86 % of elderly rheumatoid arthritis patients have a high risk of hip fracture [21], and there has been an increase in the number of hip fractures in recent years [22]. With regard to the treatment for fractures of arthritic hip joints in rheumatoid arthritis, hemiarthroplasty has been reported to be unsatisfactory due to central migration [8, 9], and total hip arthroplasty is generally performed for the surgical treatment for arthritic hip lesions. In contrast, there are no definitive data on the treatment for intracapsular fractures in rheumatoid arthritis patients without arthritic hip lesions, and surgical treatment with bipolar hemiarthroplasty or total hip arthroplasty is controversial. In this study, we reported the results of radiographic measurement after cemented bipolar hemiarthroplasty for intracapsular fracture of non-arthritic hips in 25 hips of 23 patients with rheumatoid arthritis. The results of bipolar hemiarthroplasty for non-arthritic hips were satisfactory in the medium term. No case indicated a [3-mm severe migration proximal, horizontal or medial to Ko¨hler’s line. There was no significant change in the migration distance between 1 year postoperatively and the most recent radiographs, but this study is medium-term follow-up and it might be likely trending significant change in component position in long term. Only one case showed a 1.7-mm migration proximal and medial to Ko¨hler’s line at 1 year after surgery and did not show significant progression during 6-year follow-up. Our data support bipolar hemiarthroplasty for non-arthritic displaced hip fracture. Few
reports of medium-term results of bipolar arthroplasty for proximal femoral neck fracture of non-arthritic hips in rheumatoid arthritis patients are available, and all describe no apparent central migration in radiographic measurement and no hip symptoms after surgery [10, 23, 24]. Total hip arthroplasty should be performed for displaced femoral neck fractures in hips with apparent rheumatoid changes and active synovitis. This study had a number of limitations. The first is the small number of patients treated with bipolar hemiarthroplasty. In our series, bipolar hemiarthroplasty was used for displaced hip fractures in non-arthritic hip joints with radiographic Larsen grade 0, while total hip arthroplasty was performed in displaced hip fractures with rheumatoid lesions. Therefore, the number of bipolar hemiarthroplasty cases was limited. We investigated prosthesis migration radiographically and did not evaluate clinical scores, physical findings or rheumatoid arthritis disease activity. We conclude that in femoral neck fractures in rheumatoid arthritis patients without arthritic changes, the results of bipolar hemiarthroplasty are comparable to those of total hip arthroplasty, and compared with total hip arthroplasty, this technique is less invasiveness and less expensive. Hemiarthroplasty thus seems to be indicated for nonarthritic hip fractures in patients with rheumatoid arthritis, but this study has small sample size, likely underpowered and medium-term follow-up, and it remains unclear whether the outer-head prosthesis continues to protrude in long term, so a larger number of cases and longer follow-up are required to determine the optimal treatment.
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Eur J Orthop Surg Traumatol Conflict of interest
None.
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