Juvenile rheumatoid arthritis is best defined as a chronic idiopathic synovitis of childhood. Broadly, it represents a complex systemic process involving a generalized failure of autoimmunity. Yet the specific etiology remains unclear, and even the nomenclature can be confusing. George Still first described the syndrome in 1897 in 22 children and the disease still bears his name in some regions. More recently in North America, the American Rheumatology Association redefined juvenile rheumatoid arthritis as arthritis lasting >6 weeks in duration with an onset before age 16 years. The European literature however refers to the same disease process as juvenile chronic arthritis, but extends the minimum duration of symptoms to >3 months and also encompasses spondyloarthropathies. In an attempt to minimize confusion, the International League of Rheumatologists in 1997 proposed the consensus term juvenile idiopathic arthritis.1 Juvenile idiopathic arthritis includes all idiopathic arthropathies affecting children. Despite the initial enthusiasm to standardize nomenclature, it remains to be seen whether this term will be accepted in the orthopedic literature.
Figure 1: A 27-year-old woman with bilateral juvenile rheumatoid arthritis. Note characteristic hip deformity with end stage destructive changes. Patient has classic dysplasia on both acetabular and femoral side with associated soft-tissue contractures.
Among children, juvenile rheumatoid arthritis is the most common rheumatic disease and one of the most common chronic illnesses.2 It affects up to 60,000 to 100,000 children annually in North America alone. The effects are multisystemic and sometimes devastating. Several subtypes exist based on the predominant physical and laboratory findings presenting during the first six months. The vast majority of children with juvenile rheumatoid arthritis have a favorable prognosis, entering adulthood in long-term remission without significant sequelae.3 The other 25%, including those with early age of onset and those with rheumatoid factor positive polyarticular disease, carry a more guarded prognosis. In addition to myriad extra-articular manifestations, the progressive deterioration of large joints may lead to chronic pain and disability. Psychosocial development is further affected as low self-esteem, poor body image, and limited independence are magnified in the adolescent population.4
At a gross level, the pathophysiology involves an aggressive proliferative joint synovitis that attacks both articular cartilage and physeal growth cartilage. Destructive surface changes contribute to pain and loss of motion, while ongoing growth disturbances and contractures produce further deformity (Figure 1). Locally in the hip, acetabular and femoral dysplasia may progress, and systemically, an overall arrest of growth during active growth phases is well-documented.5 Fortunately ongoing research is expanding our understanding of the disease process at a basic sciences level.
Although there are likely to be multiple initiating factors, researchers have identified a genetic predisposition in some host families. There is an increased familial occurrence in those children with HLA-B27 and HLA-DR haplotypes.6 Other environmental triggers implicate antecedent bacterial and viral infection, although a definitive causative relationship is not yet documented. Work also has progressed in identifying the role of interleukin and cytokine over-expression. Mapping studies demonstrate recurring variants in IL-6 and IL- genotypes in patients with systemic disease.7 Further elucidation of disease pathways will lead to the development of more targeted therapies and earlier identification of those at risk.
The most critical intervention in early stages of hip disease remains medical treatment. Medications can effectively calm the inflammatory state in the majority of patients. Traditional nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used, though the applicability of more selective COX-II inhibitors is currently under investigation. One third of patients however will continue to have symptoms refractory to NSAIDS and require the use of disease modifying drugs, or disease-modifying anti-rheumatic drugs.8
Drugs such as sulfasalazine, methotrexate, and corticosteroids are effective in minimizing symptoms, but also subject patients to the increased morbidity of related side effects. Methotrexate is a first choice among second-line drugs, but also carries potential risks of bone marrow suppression and hepatotoxicity. Long-term gluccocorticoids should be used with caution due to well-described side effects that include growth retardation and Cushing’s syndrome. Rheumatologists also are currently investigating the role of TNF- antagonists. These are a class of powerful immunosuppressants that effectively diminish the amount of circulating TNF-, a potent proinflammatory. Although early results have shown dramatic inductions of remission in some patients, concerns remain regarding the cost, availability, and possibility of increased infection risks.
Surgical alternatives in the early stages of hip disease also allow the physician to treat hip disease locally. Contractures often are an integral aspect of hip pathology, and contribute to structural deformity over time. Several studies with intermediate follow-up have demonstrated encouraging clinical results after limited muscle release with adductor and psoas tenotomies. Moreno Alvarez et al9 reviewed 27 patients after five years and noted improved overall mobility. Mogensen et al10 noted transient improvement in 17 patients reviewed after four years, and Swann and Ansell11 recorded lasting improvements in motion after limited release in 52 patients. Poor results may be expected, however, in advanced degenerative changes.12
Although open hip synovectomy was once routine decades ago, it has since fallen from favor. A review by Albright et al13 demonstrated only short-term relief in patients after synovectomy with no alteration in the ultimate outcome of those hips. Further, these patients were exposed to the significant risks of an open hip dislocation. Heimkes and Stotz14 reported no improvement in function or motion and progression of joint destruction after only 2 years using this technique. Minimally invasive techniques may present a better alternative in this area. The effectiveness of arthroscopy in controlling juvenile rheumatoid arthritis induced synovitis around the knee has been well-documented.15 The use of hip arthroscopy in children with juvenile rheumatoid arthritis was reported as early as 1981 by Holgersson et al16 who successfully used the technique as a diagnostic tool in 13 patients. Future developments in hip arthroscopy may eventually allow surgeons to achieve a more thorough synovectomy without the associated morbidity of an open dislocation.
The most promising therapy, however, is also the least invasive and the most effective. Sherry17 recently reported that periodic steroid injections into the hip were the most important recent development in joint preservation in children with juvenile rheumatoid arthritis. Numerous studies have shown that periodic injections predictably decrease pain and improve mobility.18,19 Imaging studies using serial magnetic resonance imaging scans have further identified that routine injections visibly decrease pannus formation in the joint.20
Total Hip Replacement
Most physicians would prefer to pursue a cautious and conservative approach in these young patients. In end-stage hip disease, however, the range of alternatives is severely limited. Hip fusion is contraindicated in this subset with often polyarticular and bilateral hip disease, and long-term reports on hemiarthroplasty are discouraging.21 Rather, total hip replacement (THR) is emerging as the standard of care. The earliest historical reports of THR in young patients raised significant concerns. Separate reports by Chandler et al,22 Dorr et al,23 and Roach and Paradies24 noted discouraging rates of early failure in young active patients. It appears, though, that patients with juvenile rheumatoid arthritis may have relatively improved outcomes, as they may have more limited demands.23
Pain relief in these patients has proven to be predictable after THR. Chmell et al25 reviewed 102 patients for a minimum of 10 years and noted that 76% of patients who had cemented THRs were pain free at follow up. Maric and Haynes26 reviewed 17 patients and noted that 100% remained pain free. In 29 patients with a mean follow up of 4.5 years, Haber and Goodman27 noted that 93% were pain free.
Total hip replacement also offers modest gains in function. Lachiewicz et al28 reported a mean hip score of 78 in his patient population. Ruddlesdin et al29 likewise noted comparatively fewer gains in function, with 10 of 42 patients still requiring either two crutches or a wheelchair after successful surgery. Comparing scores in children with juvenile rheumatoid arthritis with those scores in series involving patients with oligoarticular osteoarthritis is difficult at best, and illustrates the need to develop more specific instruments to measure outcomes in these patients. Recognizing that these children carry more severe forms of polyarticular disease also allows all concerned parties to modify postoperative expectations preemptively.
Perhaps the most important question facing this young population concerning THR relates to prosthetic durability. Historical results with long-term follow-up are variable at best, and are limited to cemented constructs. The most expansive study to date by Lehtimaki et al30 involved a registry of 186 hips followed for 10 years. He noted 92% survival in patients who had a Charnley type prosthesis. Chmell et al25 noted 67% survival of both components at a minimum of 10 years. Other reports are less favorable. In a radiographic review of cemented hips, Williams and McCullough31 noted impending failure due to radiographic loosening in 43% of patients at only five-year follow-up. Witt et al32 and Learmonth et al33 separately reported aseptic loosening in 42% and 57% of patients, respectively.
The safe surgical management of patients with juvenile rheumatoid arthritis demands a multidisciplinary understanding and approach. A knowledgeable team of anesthesiologists, rheumatologists, social workers, and therapists is requisite in addressing the unique issues of this population. Cervical spine involvement may affect the ability to deliver general anesthesia. Synovitis creates not only unstable motion segments in the neck, but may lead to spontaneous fusions between levels that create excessive rigidity. Mandibular hypoplasia can lead to abnormalities around the jaw, and temporomandibular joint inflammation can compromise visualization of the trachea.34 These factors make routine intubation not only difficult, but also a relative contraindication. Mogensen et al35 reported 20% failed intubations in patients with juvenile rheumatoid arthritis and noted that anesthesiologists resorted to blind nasotracheal intubation. Current recommendations favor the safety of fiberoptic intubation or regional spinal epidural-based anesthesia.
The more severe forms of juvenile rheumatoid arthritis also are associated with a polyarticular presentation. Wrists, elbows, and shoulders are commonly affected, and these degenerative upper extremities become weightbearing following hip surgery. A thorough preoperative evaluation by a team of upper-extremity surgeons, physical therapists, and occupational therapists can identify and address potential areas of frustration. Advanced disease in the knees and feet contribute to a difficult rehabilitation. To improve function, feet and ankles must be plantigrade prior to hip surgery. At times the knees are more symptomatic than hips, and are occasionally a chief complaint in patients who present for THR. The operative sequence, however, prioritizes THR prior to knee surgery.36 This protocol is based on the observation that rehabilitation of a total hip with a stiff knee proceeds more easily than rehabilitation of the knee with a stiff hip. Referred pain to the knee may diminish after THR, and knee flexion contractures may be manipulated at hip surgery. Last, the rehabilitation after hip surgery is more commonly less painful, increasing the likelihood that the patient will proceed with the next stage of arthroplasty.
Rheumatologists are integral in coordinating the general and perioperative care of patients with juvenile rheumatoid arthritis. Although often well-controlled with aggressive management, patients with juvenile rheumatoid arthritis after THR may carry an increased early mortality rate as high as 18% in some series.25 A complete full body evaluation for associated systemic abnormalities including vision, pericardium, clotting factors, and spinal involvement is mandatory. The timing of medications requires careful adjustment, as agents such as methotrexate may need to be discontinued and stress dose steroids may need to be administered. Efforts to optimize the timing of interventions around school and family schedules will help minimize the psychosocial burden of chronic disease.
Exposure for arthroplasty is complicated by characteristic alterations in the soft tissue. Scott et al37 reported that most patients had >30° contracture with a total arc of motion <200°. Wide capsulectomy and soft-tissue release anteriorly and posteriorly can improve passive motion and reduce the risk of fracture during dislocation, but also are associated with an up to 15% incidence of nerve palsy. Percutaneous adductor tenotomy pre- or postoperatively reduces the risk of posterior instability and improves abduction. Bilateral hip flexion contractures furthermore force performing bilateral THR simultaneously, or closely staged apart, to prevent recurrent contacture of the operative hip. Historically, trochanteric osteotomy was an integral step in THR in these patients.28,34
Though not as prevalent today, trochanteric osteotomy affords access to the femoral neck for osteotomy and to the canal for intramedullary preparation in difficult cases. It also will allow the surgeon to correct version at the time of trochanter reattachment. A series by Ruddlesdin et al29 involving 75 patients noted that a number of surgeries required in situ femoral neck osteotomy to deal with bony ankylosis and protrusio deformity in affected hips. Due to the complexity of the surgery and soft-tissue contractures, the surgeon should avoid the temptation to use mini-incision techniques.
Skeletal immaturity and open growth physes present another technical challenge. Williams and McCullough31 observed a 67% failure rate in patients with open physes after cemented socket placement, and Learmonth et al33 implicated continued diaphyseal growth in cemented femoral stem loosening. Scott et al37 reported successful management of 11 patients with open physes. On the acetabular side, he performed triradiate epiphysiodesis with bone grafting, and on the femoral side, he selected a longer prosthetic neck to accommodate the loss of height from removal of the femoral growth plate. Although deferment until skeletal maturity may be desirable, proceeding with an earlier arthroplasty will compromise at most only 2.4 cm of growth, or 0.8% of total body height.37
The greatest risk of complications occurs intraoperatively, as reported by Colville and Raunio.34 The femoral canals in these young patients are hypoplastic, often 6-8 mm in diameter and osteopenic. The risk of fracture subsequently rises during exposure and femoral preparation. Severe proximal femoral torsion secondary to long-standing contractures and premature closure of the physes potentially affects implant version and postoperative stability. The proximal femur may be anteverted as much as 90°, hindering access to the posterior femur and raising the risk of neurovascular injury with closer proximity of the sciatic nerve. Associated cortical thinning presents a characteristic metaphyseal and diaphyseal mismatch that should be addressed at the time of implant selection for cementless fixation.
Femoral fixation either with cemented or cementless systems has proven to be reliable. Using cemented components Lehtimaki et al30 reviewed 100 patients with 92% survival of the femoral stem at 15 years. Chmell et al25 noted 85% survival at 15 years, and Lachiewicz et al,28 92% survival at 6 years, with failures associated with first generation cement techniques and varus malpositioning. Early reports of cementless fixation in patients with juvenile rheumatoid arthritis are encouraging, but are limited by small numbers of patients with only short follow-up. Lachiewicz38 later reported 100% fixation in 10 patients at 4.5 years, and Maric and Haynes26 noted 100% fixation in 4 patients at 9 years. Despite this initial enthusiasm, continued surveillance is mandatory, as reports of failing cementless stems are emerging.21
Access to a wide range of femoral components is crucial to successful surgical management. Haber and Goodman27 recommended the use of standard off-the-shelf cementless components in their population. Careful review of their patients suggests that routine usage of standard components can lead to unpredictable fixation. In their study, 29 proximal femurs were prepared for cementless components but only in 20 was stable fixation achievable, with the other 9 femoral stems being cemented. Further, only 17 of the 20 cementless stems developed stable bony ingrowth. This represents 17 (58%) of 29 patients having bony ingrown components with cementless fixation using standard components. In another series, Colville and Raunio34 reported three femoral fractures associated with the use of standard components and Scott et al37 have reported the need to customize components intraoperatively to obtain initial fixation.
Our protocol for patients with juvenile rheumatoid arthritis involves a preoperative computed tomography (CT) scan to assess accurately anteversion, bone stock, and the need for custom or modular components. Scott36 agreed that 50% of patients with juvenile rheumatoid arthritis required customized or special miniature implants. Custom components represent a readily available alternative. Though costs remain a concern, CAD-CAM derived stems can be modified according to surgeon preference, with addition of biologic coatings and alteration of stem version and extended neck angles (Figure 2). These components are used in conjunction with custom templates and instrumentation to facilitate more predictable proximal femoral preparation and decrease the risk of fracture. Other options more familiar to reconstructive surgeons include the use of modular components (Figure 3). The surgeon can readily deal with abnormal proximal femoral torsion and achieve optimum fit and fill despite metaphyseal and diaphyseal sizing mismatches. For adolescent patients, special requests should be made in advance for stem diameters measuring as small as 6 mm. If cemented designs are chosen, a variety of stems with reduced metaphyseal segments and narrow shaft diameters, similar to CDH-type designs, should be readily available.
Figure 2: Postoperative radiograph of THR using computer assisted design-computer assisted machined custom cementless prosthesis. Note extended neck length with high off-set.
Figure 3: Radiograph demonstrating alternative stem options with use of modular femoral components. These increase surgical options when dealing with metaphyseal and diaphyseal mismatch as well as characteristic torsional changes in the proximal femur.
The variation in acetabular deformity presents another series of surgical challenges. Two forms of acetabular deformity are prevalent. The acetabulum may have a shallow dysplastic morphology with a laterally and superiorly subluxated hip similar to patients with congenital hip dysplasia. A more common deformity is protrusio with superior medial migration of the hip and attendant central bone loss (Figure 4). With either deformity, reconstruction to the anatomic hip center is critical. Success with high hip centers is reported by Schutzer and Harris,39 but the characteristic lack of bone in the ilium of patients with juvenile rheumatoid arthritis may compromise a high socket in this thin bone. Lachiewicz et al28 reported twice the rate of failure in cups placed >5 mm outside the anatomic hip center. Mogensen et al35 described higher loosening rates in acetabulae with preoperative lateral bone deficiency. Autogenous bone graft from the resected femoral head should be used to augment cavitary defects. Availability of small diameter reamers and implants is needed to prepare the hypoplastic acetabulum with a narrow anteroposterior diameter. The typical size of the metal acetabular component is <50 mm, which necessarily means a thin polyethylene liner.
Wear and related aseptic loosening are currently emerging as the greatest threats to long-term failure. Although final positioning of the implant may be limited by available bone stock, current studies support placement of the cup in 40° of abduction to minimize polyethylene wear.40 With small diameter cups and standard bearing surfaces, smaller head diameters should be used, as Chmell et al25 observed that hips with >28-mm head diameters had an accelerated rated of failure. When using 22-mm heads, the diameter of the femoral neck should allow at least a 2:1 head/neck ratio to reduce the risk of dislocation. Alternative bearing surfaces that are not limited by issues of liner thickness may prove to be a better option for this specific population. Further investigation of ceramic, metal, and cross-linked polyethylene is warranted.
The oldest reports of cemented socket fixation reported alarming rates of failure and loosening. Lachiewicz et al28 reported 74% failure of cemented cups in 6 years. The presence of associated global pelvic osteolysis adds to the complexity of reconstructing these failures. Modern cementless acetabular component technology has improved durability compared to historical results with cemented cups, although these studies are limited by a smaller series of patients with shorter periods of follow-up. Haber and Goodman27 noted 100% success in 29 patients at 4.5 years. Anecdotal reports, however, have shown that cementless sockets can fail (Figure 5).
Figure 4: Typical variation of acetabular degeneration with protrusio and loss of iliac bone.
Figure 5: Radiograph taken 7 years postoperatively with failed cementless cup with associated osteolysis. Note circumferential radiolucent lines in all three zones. This cup has also migrated from prior evaluation.
Hip arthropathy in juvenile rheumatoid arthritis encompasses many stages. Therapy in the initial phases should focus on the conservative treatment of generalized inflammation and preservation of the hip’s structural integrity. In advanced degeneration, few alternatives remain except arthroplasty. Total hip replacement currently represents the standard of care. While pain relief and restoration of function are predictable, surgery presents a host of technical issues warranting careful preparation and foreknowledge.
Our recommendation involves a multidisciplinary approach: preoperative CT scans, custom components, and cementless fixation. Despite a growing understanding of the challenges implicit in THR, implant survival in young patients will remain a concern. Investigation of wear and aseptic loosening merits continued investigation, as well as further follow-up of cementless fixation. Improved durability and the minimization of the morbidity associated with subsequent revision surgery are our new priorities.
- Ramsey SE, Bolaria RK, Cabral DA, Malleson PN, Petty RE. Comparison of criteria for the classification of childhood arthritis. J Rheumatol. 2000; 27:1283-1286.
- Peterson LS, Mason T, Nelson AM, O’Fallon WM, Gabriel SE. Juvenile rheumatoid arthritis in Rochester, Minnesota 1960-1993. Is the epidemiology changing? Arthritis Rheum. 1996; 39:1385-1390.
- Schaller JG. Chronic arthritis in children. Juvenile rheumatoid arthritis. Clin Orthop. 1984; 182:79-89.
- Beales JG, Holt PJ, Keen JH, Mellor VP. Children with juvenile chronic arthritis: their beliefs about their illness and therapy. Ann Rheum Dis. 1983; 42:481-486.
- Davies UM, Rooney M, Preece MA, Ansell BM, Woo P. Treatment of growth retardation in juvenile chronic arthritis with recombinant human growth hormone. J Rheumatol. 1994; 21:153-158.
- Burgos-Vargas R, Pacheco-Tena C, Vazquez-Mellado J. Juvenile-onset spondyloarthropathies. Rheum Dis Clin North Am. 1997; 23:569-598.
- Forre O, Smerdel A. Genetic epidemiology of juvenile idiopathic arthritis. Scand J Rheumatol. 2002; 31:123-128.
- Lovell DJ, Giannini EH, Brewer EJ Jr. Time course of response to nonsteroidal antiinflammatory drugs in juvenile rheumatoid arthritis. Arthritis Rheum. 1984; 27:1433-1437.
- Moreno Alvarez MJ, Espada G, Maldonado-Cocco JA, Gagliardi SA. Longterm followup of hip and knee soft tissue release in juvenile chronic arthritis. J Rheumatol. 1992; 19:1608-1610.
- Mogensen B, Brattstrom H, Svantesson H, Lidgren L. Soft tissue release of the hip in juvenile chronic arthritis. Scand J Rheumatol. 1983; 12:17-20.
- Swann M, Ansell BM. Soft-tissue release of the hips in children with juvenile chronic arthritis. J Bone Joint Surg Br. 1986; 68:404-408.
- Hyman BS, Gregg JR. Arthroplasty of the hip and knee in juvenile rheumatoid arthritis. Rheum Dis Clin North Am. 1991; 17:971-983.
- Albright JA, Ablright JP, Ogden JA. Synovectomy of the hip in juvenile rheumatoid arthritis. Clin Orthop. 1975; 106:48-55.
- Heimkes B, Stotz S. Results of late synovectomy of the hip in juvenile chronic arthritis. Z Rheumatol. 1992; 51:132-135.
- Rydholm U, Elborgh R, Ranstam J, Schroder A, Svantesson H, Lidgren L. Synovectomy of the knee in juvenile chronic arthritis. A retrospective, consecutive follow-up study. J Bone Joint Surg Br. 1986; 68:223-228.
- Holgersson S, Brattstrom H, Mogensen B, Lidgren L. Arthroscopy of the hip in juvenile chronic arthritis. J Pediatr Orthop. 1981; 1:273-278.
- Sherry DD. What’s new in the diagnosis and treatment of juvenile rheumatoid arthritis. J Pediatr Orthop. 2000; 20:419-420.
- Boehnke M, Behrend R, Dietz G, Kuster RM. Intraarticular hip treatment with triamcinolonehexacetonide in juvenile chronic arthritis. Acta Univ Carol [Med] (Praha). 1994; 40:123-126.
- McCullough CJ. Surgical management of the hip in juvenile chronic arthritis. Br J Rheumatol. 1994; 33:178-183.
- Eich GF, Halle F, Hodler J, Seger R, Willi UV. Juvenile chronic arthritis: imaging of the knees and hips before and after intraarticular steroid injection. Pediatr Radiol. 1994; 24:558-563.
- Yun A, Martin S, Zurakowski D, Scott R. Bipolar hemiarthroplasty in juvenile rheumatoid arthritis: long-term survivorship and outcomes. J Arthroplasty. 2002; 17:978-986.
- Chandler HP, Reineck FT, Wixson RL, McCarthy JC. Total hip replacement in patients younger than thirty years old. A five-year follow-up study. J Bone Joint Surg Am. 1981; 63:1426-1434.
- Dorr LD, Takei GK, Conaty JP. Total hip arthroplasties in patients less than forty-five years old. J Bone Joint Surg Am. 1983; 65:474-479.
- Roach JW, Paradies LH. Total hip arthroplasty performed during adolescence. J Pediatr Orthop. 1984; 4:418-421.
- Chmell MJ, Scott RD, Thomas WH, Sledge CB. Total hip arthroplasty with cement for juvenile rheumatoid arthritis. Results at a minimum of ten years in patients less than thirty years old. J Bone Joint Surg Am. 1997; 79:44-52.
- Maric Z, Haynes RJ. Total hip arthroplasty in juvenile rheumatoid arthritis. Clin Orthop. 1993; 290:197-199.
- Haber D, Goodman SB. Total hip arthroplasty in juvenile chronic arthritis: a consecutive series. J Arthroplasty. 1998; 13:259-265.
- Lachiewicz PF, McCaskill B, Inglis A, Ranawat CS, Rosenstein BD. Total hip arthroplasty in juvenile rheumatoid arthritis. Two to eleven-year results. J Bone Joint Surg Am. 1986; 68:502-508.
- Ruddlesdin C, Ansell BM, Arden GP, Swann M. Total hip replacement in children with juvenile chronic arthritis. J Bone Joint Surg Br. 1986; 68:218-222.
- Lehtimaki MY, Lehto MU, Kautiainen H, Savolainen HA, Hamalainen MM. Survivorship of the Charnley total hip arthroplasty in juvenile chronic arthritis. A follow-up of 186 cases for 22 years. J Bone Joint Surg Br. 1997; 79:792-795.
- Williams WW, McCullough CJ. Results of cemented total hip replacement in juvenile chronic arthritis. A radiological review. J Bone Joint Surg Br. 1993; 75:872-874.
- Witt JD, Swann M, Ansell BM. Total hip replacement for juvenile chronic arthritis. J Bone Joint Surg Br. 1991; 73:770-773.
- Learmonth ID, Heywood AW, Kaye J, Dall D. Radiological loosening after cemented hip replacement for juvenile chronic arthritis. J Bone Joint Surg Br. 1989; 71:209-212.
- Colville J, Raunio P. Total hip replacement in juvenile rheumatoid arthritis. Analysis of 59 hips. Acta Orthop Scand. 1979; 50:197-203.
- Mogensen B, Brattstrom H, Ekelund L, Lidgren L. Total hip replacement in juvenile chronic arthritis. Acta Orthop Scand. 1983; 54:422-430.
- Scott RD. Total hip and knee arthroplasty in juvenile rheumatoid arthritis. Clin Orthop. 1990; 259:83-91.
- Scott RD, Sarokhan AJ, Dalziel R. Total hip and total knee arthroplasty in juvenile rheumatoid arthritis. Clin Orthop. 1984; 182:90-98.
- Lachiewicz PF. Rheumatoid Arthritis of the Hip. J Am Acad Orthop Surg. 1997; 5:332-338.
- Schutzer SF, Harris WH. High placement of porous-coated acetabular components in complex total hip arthroplasty. J Arthroplasty. 1994; 9:359-367.
- Hirakawa K, Mitsugi N, Koshino T, Saito T, Hirasawa Y, Kubo T. Effect of acetabular cup position and orientation in cemented total hip arthroplasty. Clin Orthop. 2001; 388:135-142.
Drs Yun and Dorr are from the Arthritis Insitute, Centinela Hospital, Ingelwood, Calif; Dr Figgie is from the Hospital for Special Surgery, New York, NY; and Dr Scott is from Brigham and Women’s Hospital, Boston, Mass.
The material presented in any Vindico Medical Education continuing education activity does not necessarily reflect the views and opinions of Vindico Medical Education or SLACK Incorporated. Neither Vindico Medical Education or SLACK Incorporated nor the authors endorse or recommend any techniques, commercial products, or manufacturers. The authors may discuss the use of materials and/or products that have not yet been approved by the US Food and Drug Administration. All readers and continuing education participants should verify all information before treating patients or using any product.
Drs Yun, Figgie, Dorr, and Scott have no industry relationship to declare.
Reprint requests: Andrew G. Yun, MD, The Arthritis Institute, Centinela Hospital, 501 E Hardy St, Inglewood, CA 90301.