CHAPTER SYNOPSIS
Juvenile rheumatoid arthritis is a chronic childhood illness characterized by multiple joint involvement and systemic manifestations. The symptoms can be severely limiting and difficult to manage with medications alone. Surgical management often becomes necessary when medical treatment fails to provide adequate symptom relief, with total hip arthroplasty being the most common procedure.
IMPORTANT POINTS
- 1
Joint pain occurs less commonly than in adult rheumatoid arthritis and usually is not the primary surgical indication.
- 2
Primary surgical indications for total hip arthroplasty in juvenile rheumatoid arthritis include significant activity limitation and hampered mobility.
- 3
Skeletal immaturity makes this a complicated procedure but it is not an absolute contraindication.
CLINICAL/SURGICAL PEARLS
- 1
Medical management of juvenile rheumatoid arthritis includes nonsteroidal antiinflammatory drugs and disease-modifying antirheumatic drugs.
- 2
Because of the systemic nature of juvenile rheumatoid arthritis, a multidisciplinary approach to perioperative care should be used, including evaluations by a social worker, physiotherapist, rheumatologist, and orthopedic surgeon.
- 3
Surgical options include synovectomy, soft tissue contracture release, hemiarthroplasty, and total hip arthroplasty.
- 4
Total hip arthroplasty provides the most predictable long-term outcomes when careful patient selection and preoperative planning are used.
CLINICAL/SURGICAL PITFALLS
Multiple special considerations exist regarding perioperative management and surgical technique in these patients, including the following:
- 1
Medication adjustments in the perioperative period
- 2
Anesthesia issues, such as cervical instability and temporomandibular joint alterations
- 3
Multiple joint involvement
- 4
Decreased bone density
- 5
Small stature
- 6
Difficult surgical exposure
- 7
Changes in femoral architecture
- 8
Structure differences in the acetabulum
- 9
Component fixation challenges
INTRODUCTION
Juvenile rheumatoid arthritis (JRA) is a chronic illness of early childhood and adolescence. The incidence of the disease is approximately 11.7 cases per 100,000 population per year, affecting an estimated 300,000 children in the United States. JRA affects twice as many females as males. It is the most frequent connective tissue disease of childhood and a significant source of functional impairment and disability.
JRA recently has been redefined by the American Rheumatology Association as arthritis lasting longer than 6 weeks with an onset before 16 years of age. In Europe, the same disease is known as juvenile chronic arthritis; there the definition includes a duration of symptoms of more than 3 months. JRA has been categorized into three major types based on the clinical and laboratory findings seen during the initial 6 months of disease presentation ( Table 16-1 ). Systemic-onset JRA is characterized by involvement of at least a single joint concurrent with fever, rash, and disease involvement of other internal organs, such as the heart, lungs, or liver. Pauciarticular (also referred to as oligoarticular) disease affects four or fewer joints and occurs in up to 50% of children with JRA. It has a notable association with chronic iridocyclitis. A diagnosis of pauciarticular JRA before the age of 7 years with a positive antinuclear antibody titer is associated with a 90% risk of developing this form of uveitis. Ophthalmologic screening every 3 to 6 months for the initial 5 years after diagnosis of JRA is recommended. Polyarticular disease involves five or more joints and occurs in 40% of children with JRA. JRA can be either seropositive or seronegative.
| Pauciarticular | Polyarticular | ||||
|---|---|---|---|---|---|
| Systemic | Type I | Type II | RF Negative | RF Positive | |
| Sex predominance | M=F | F | M | F | F |
| Typical age of onset | Any | <5 | >8 | <5 | >8 |
| Rheumatoid factor | − | − | − | − | + |
| Antinuclear antibody | − | 60%+ | − | 25%+ | 60%+ |
| Uveitis | NA | 30%+ | NA | <10%+ | NA |
| % of patients with JRA | 10 | 40 | 15 | 25 | 10 |
Large joint involvement predominates over smaller joint disease, with the knee and ankle most commonly afflicted. Incidence of hip involvement has been reported to occur in as many as 64% of patients. Despite its more variable involvement, hip pathology has been cited as the most significant source of physical restriction. The pathophysiology of the disease involves an aggressive proliferation of joint synovium and effusion, which cause pain and secondary muscle spasm. With persistent synovial hypertrophy, articular cartilage destruction and physeal growth injury of both the femur and acetabulum may occur. These destructive changes lead to a constellation of symptoms, including pain, loss of motion, and joint contractures. Coxa magna may be seen through overgrowth of the femoral neck and a varus deformity. Avascular necrosis may occur, usually as a result of the prolonged use of corticosteroids. Hip subluxation or dislocations may be seen with more severe cases. Spontaneous hip fusion may occur but is quite rare.
Further support for the importance of hip joint involvement in JRA comes from a study by Modesto et al that reviewed the charts of 91 children with systemic onset JRA for a minimum of 3 years. They collected clinical and biologic variables at baseline and at 6 months to identify predictive factors for those who would develop severe multiple-joint destruction. Through the use of multivariate logistic regression modeling, the presence of hip involvement and polyarthritis were independent predictors of a poorer articular outcome. Lang et al reported on children with systemic-onset JRA and showed a high incidence of early-onset hip joint degeneration. Twenty (48%) of the 42 children had radiographic evidence of hip arthritis, including seven with hip subluxation. One patient had hip subluxation develop within 2 years, and subluxation developed in the remaining six children within 6 years of disease onset.
The optimal study for imaging the hip joint traditionally has been the plain radiograph, but magnetic resonance imaging (MRI) and ultrasound (US) may offer some clinical advantages. The use of US to detect hip disease in its early stages is attractive because of the lower costs compared with MRI and potentially comparable sensitivity. A study of 53 patients by Fedrizzi et al showed that US detected hip joint abnormalities in 47% of patients compared with 19% for conventional radiographs. Moreover, severe radiographic changes in the hips were found 2 to 3 years later in three of nine patients who initially had normal radiographs but abnormal ultrasounds. The answer to the question of what the best test for imaging the hip joint in JRA is has yet to be decided, but one author suggested that (1) plain films and MRI may be best for initial staging; (2) MRI is the best test for assessing inflammatory changes in the joint; and (3) US is good for assessing effusions, pannus, and treatment response.
JRA generally has a better prognosis than the adult form. Many children achieve permanent remission of their disease as they enter adulthood and, of those who do have persistent synovitis, not all develop bony erosion or cartilage damage. Risk factors for a more aggressive form of the disease include an early age of onset and rheumatoid factor (RF)–positive polyarticular disease. Joint destruction and arthritis will likely develop in 50% of those patients with persistent RF-positive disease compared with 10% of those with RF-negative disease.
Psychosocial development of the child with JRA may be affected by poor self-esteem, poor body image, and limited independence. These children often have multiple school absences, and their inability to participate in physical education reflects the severity of their disease.
Infection has been suggested as a cause of both the onset and exacerbations of JRA. Multiple viral and bacterial antigens have been theorized to promote an inappropriate host autoimmune response leading to the clinical manifestations of the disease. The etiology of the disease likely is multifactorial; however, newer research indicates an inherited genetic predisposition. An increased familial incidence of JRA exists in children with HLA-B27 and HLA-DR haplotypes. Further study of the genetics and disease pathways will aid in early detection and targeted therapies.
MEDICAL MANAGEMENT OF JUVENILE RHEUMATOID ARTHRITIS
Medical management of JRA, like other autoimmune diseases, has greatly advanced during the past few decades. Current therapeutic regimens have improved quality of life and often have prolonged or circumvented the need for joint arthroplasty. Conversely, when surgery is considered, these pharmaceuticals add another layer of intricacy. Infection rates after THA have been reported to be approximately 2.6 times higher in rheumatoid patients compared with those treated for osteoarthritis. Medical management likely contributes, at least in part, to this complication. However, perioperative use of these medications is necessary for sufficient disease control and enables participation in postsurgical rehabilitation. The perioperative medical management of rheumatoid disease can be exceedingly complex and may be facilitated with the assistance of a rheumatologist.
In the early stages of hip involvement, nonsteroidal antiinflammatory drugs (NSAIDs) or selective cyclooxygenase-2 inhibitors traditionally have been used and are effective at controlling the level of joint synovitis and inflammation. These medications generally are well tolerated but are associated with gastrointestinal irritation, potential nephrotoxicity, and iatrogenic coagulopathy. Unfortunately, approximately 30% of patients continue to have symptoms refractory to NSAIDS and require the use of disease-modifying antirheumatic drugs (DMARDs), which include methotrexate, pyrimidine synthesis inhibitors, and tumor necrosis factor (TNF) antagonists.
Corticosteroids can provide significant disease control and symptomatic relief in patients with JRA. Periodic intraarticular injections of steroids also have been shown to have a predictable and substantial benefit on joint pain and mobility. However, in the perioperative period corticosteroids can result in varying gradations of immunosuppression, potentially compromising healing and infection risks during early convalescence. In addition, corticosteroid use over many years can lead to growth retardation and Cushing syndrome.
Methotrexate is a folate analogue providing antiinflammatory activities by inhibiting cytokine production (e.g., interleukin-1, interleukin-8, TNF) and prevention of neovascularization. Methotrexate can be extremely effective in controlling JRA symptoms; however, patients typically experience significant disease recrudescence after discontinuation of the medication. Rheumatoid disease flares typically occur within 4 weeks of discontinued use. Methotrexate also can be associated with significant side effects, with long-term use being associated with bone marrow suppression and hepatotoxicity.
Pyrimidine synthesis inhibitors (e.g., leflunomide [Arava]) and TNF-α antagonists have been used with tremendous promise in the past few years. Commonly used TNF antagonists include etanercept (Embrel), adalimumab (Humira), and infliximab (Remicade). Pyrimidine synthesis inhibitors interfere with DNA replication, preferentially affecting rapidly dividing cell lines, including lymphocytes. TNF is a proinflammatory cytokine believed to play a key role in the joint destruction seen in rheumatoid disease. Opportunistic infections, including tuberculosis, Pneumocystis carinii pneumonia, and a number of fungi, have been attributed to TNF antagonist use. Musculoskeletal infections (e.g., psoas abscess) and bacteremia also have been reported with their use.
Physiotherapy and stretching exercises also play an important role and should be initiated early in the course of the disease. Because of chronic joint synovitis, patients often develop joint capsule and periarticular muscle contractures, particularly of the adductor and iliopsoas muscles. The primary benefit of an early stretching program is to delay the onset of a fixed joint contracture.
SURGICAL INDICATIONS
THA remains controversial in young patients and generally is reserved for skeletally mature individuals. The potential for continued growth after THA has raised concerns over eventual leg-length discrepancy and long-term component fixation. Approximately 25% of patients with JRA continue to grow after THA. Although improved survival rates of THA are seen with increasing patient age, skeletal immaturity is not an absolute contraindication. The proximal femoral epiphysis normally contributes 3 mm of annual longitudinal growth and less than 1% of overall expected height. However, the overall growth in patients with JRA generally is restricted as a result of disease. The relation between diaphyseal expansion and long-term component durability remains unclear.
Unlike adult rheumatoid arthritis, joint pain is a less frequent symptom and typically is not the primary indication for surgical intervention. Significant activity limitation and hampered mobility are the most frequently reported indications for hip arthroplasty.
The physical improvement imparted to these patients after joint arthroplasty is undeniable. Pain relief and a reduced dependence on wheelchairs and other assistive devices for ambulation are widely reported. Still, orthopedic intervention should be considered within the context of a multidisciplinary medical approach. Other treatment modalities, including medications, physical therapy, synovectomy, and soft tissue release, should always be considered before joint replacement.
PERIOPERATIVE CONSIDERATIONS
Medical Management
Of note, JRA is a systemic disorder with the potential for additional skeletal and multiorgan system involvement. A multidisciplinary approach to the perioperative care of these patients should include the expertise of a social worker, physiotherapist, rheumatologist, and orthopedic surgeon. A thorough medical evaluation by the pediatrician, internist, and/or rheumatologist should be included in the preoperative stages. Sochart and Porter reported a 43% mortality rate, at an average of 169 months after arthroplasty, in patients with rheumatoid arthritis during their 20-year follow-up period. Chmell et al reported an overall mortality rate of 18% in patients who underwent THA before age 30 years (average age at death, 27.6 years). Only a single death occurred in the immediate perioperative period.
Because of the increased risks associated with the use of NSAIDs and DMARDs during the perioperative period, discontinuation or dose adjustment usually is indicated for these agents. NSAIDs generally are recommended to be withheld from three to five half-lives before surgery. This roughly translates to discontinued use 1 to 2 days for short-acting NSAIDs (e.g., ibuprofen, indomethacin) and up to 3 to 6 days before surgery for longer acting drugs (e.g., naproxen, piroxicam). Aspirin should be discontinued 7 to 10 days before surgery to replenish adequate platelet activity. Resumption of NSAID use typically is withheld a minimum of 7 to 14 days during the initial postoperative period after THA. Patients taking long-term corticosteroids also may require stress dosing within the immediate perioperative period because of concerns regarding adrenal insufficiency. Friedman et al have questioned the need for stress dose steroids in patients undergoing orthopedic surgical procedures. Nevertheless, any alteration in corticosteroid administration should be determined on an individual basis.
Unfortunately, no clear guidelines exist regarding methotrexate administration in the perioperative period. Reduced complications have been observed when methotrexate is withheld for 2 weeks before the procedure and during the initial 2 weeks postoperatively. Conversely, significantly fewer complications have been observed in patients continuing methotrexate compared with patients discontinuing use for 4 weeks in the perioperative period. At Brigham and Women’s Hospital, the authors typically hold methotrexate for 1 week before and after THA. Temporary discontinuation of methotrexate is largely for concerns of renal dysfunction and potential methotrexate toxicity. Reduced oral intake of folate, which can occur in the perioperative period, may lead to methotrexate toxicity. Renal disease and insufficiency further predispose patients to potential toxicity. The most significant sequelae of methotrexate toxicity are bone marrow suppression and neutropenia.
Similarly, limited information and few evidence-based guidelines currently are available to guide the perioperative use of pyrimidine synthesis inhibitors and TNF antagonists. Current literature shows variable perioperative complications and infection rates associated with these medications. Howe et al currently recommend cessation of leflunomide at least 24 to 48 hours before THA and resuming use 1 to 2 weeks after surgery, once antibiotic therapy is completed and narcotic use is minimal. With the intermittent dosing schedules of the TNF antagonists, arthroplasty should be scheduled toward the end of the dosing interval and the next dose withheld for 10 to 14 days postoperatively.
Anesthesia-Related Issues
Evaluation of JRA-related cervical spine involvement, both instability and ankylosis, is an undeniably important portion of the preoperative workup because these conditions may preclude the use of a general anesthetic and affect patient positioning during surgery. Laiho et al analyzed cervical spine radiographs of 159 patients with JRA after reaching skeletal maturity. Pathologic changes were observed in 62% of patients. The most frequent findings included multilevel apophyseal ankylosis (41%), atlantoaxial impaction (25%), and atlantoaxial subluxation (17%).
Cervical spine pathology typically is more common in individuals with greater systemic disease involvement. Hensinger et al studied 120 patients with juvenile arthritis clinically and radiographically for cervical spine disease. Of the 57 patients with pauciarticular JRA, none exhibited clinical signs or symptoms and only one patient had minor cervical radiographic findings of disease. However, both clinical and radiographic pathology were common in the 63 remaining patients with polyarticular or systemic-onset JRA.
Collins et al retrospectively reviewed the cervical radiographs of 113 rheumatoid patients previously treated with total knee arthroplasty or THA. Sixty-one percent of these patients had at least one finding of atlantoaxial impaction, atlantoaxial subluxation, or subaxial subluxation. Most importantly, 50% of those with radiographic documentation of cervical instability did not exhibit clinical signs or symptoms at the time of surgery. These studies highlight the importance of diligent preoperative evaluation, which should include cervical spine radiographs with flexion and extension lateral views.
In addition to cervical pathology, temporomandibular joint involvement and mandibular hypoplasia also are frequently encountered in JRA patients. This can lead to difficulties around the jaw, including visualization of the trachea during intubation. With high-resolution computed tomography, Ronchezel et al noted alterations of the temporomandibular joint in 50% of patients with JRA. Sixty-nine percent exhibited additional orthodontic abnormalities from micrognathia. Pathoanatomic alterations were most frequently observed in those with polyarticular and systemic-onset disease. Stabrun reported similar findings of temporomandibular joint abnormalities and mandibular hypoplasia in all 26 JRA patients longitudinally followed for 6 years.
Cervical spine disease and mandibular abnormalities may present the anesthesia team with a difficult, and potentially hazardous, endotracheal intubation. Furthermore, these issues may necessitate the use of fiberoptic laryngoscope assistance or awake nasotracheal intubation techniques. Alternatively, regional anesthesia could be considered and is even preferred by some authors for all JRA patients.
Multiple Joint Involvement
Patients often have involvement of multiple joints such as knees, feet, shoulders, and elbows, which may impair the postoperative rehabilitation process and affect operative decisions. A thorough preoperative evaluation by the occupational and physical therapists may help facilitate a patient’s recovery by having resources available such as splints, braces, and assistive walking aids.
Concomitant bilateral hip involvement or debilitating ipsilateral hip and knee arthritis can readily occur. In the case of the latter, performing the THA before undertaking total knee arthroplasty is widely recommended. This is in part because of the ability to rehabilitate a hip above a painful arthritic knee but not the reverse. Scott also notes that easier hip rehabilitation often garners patient trust and confidence as additional surgery is recommended. Furthermore, issues of referred knee pain and contractures can be addressed at the time of hip surgery. One indication for initially performing a total knee arthroplasty is the presence of a fixed knee flexion contracture of 45 degrees or more.
In a JRA patient with significant bilateral hip disease and fixed hip flexion contractures, bilateral THA has been advocated. Anesthesia-related concerns as well as other physical, social, and emotional issues have been cited as indications for performing simultaneous THAs. However, investigations comparing unilateral THA and simultaneous bilateral procedures consistently report higher rates of transfusion, longer hospitalization and convalescence periods, decreased hip motion and greater incidence of heterotopic ossification, and increased need for repeat hip surgery in the bilateral groups. Higher incidences of perioperative pulmonary complications and increased mortality rate within the first postoperative year also have been reported. Although none of this literature is focused on patients with JRA, a safe assumption is that these findings hold true in this population, if not to a greater degree. Sequential THA within a single hospitalization has been advocated as a potential alternative. Nevertheless, decisions regarding staged versus simultaneous procedures should always be made on an individual basis.
ALTERNATIVE SURGICAL TREATMENT
Synovectomy
Synovectomy has been proposed as a potential first-line surgical intervention for JRA. Improved results are associated with early intervention, especially in cases of mild to moderate disease activity. Early literature generally showed only modest short-term symptom relief, with no change in the natural history of the disease. In these studies the benefits were found not to outweigh the potential risk of open hip dislocation. Other studies have shown slightly more promising results. Heimkes and Stotz were able to demonstrate a benefit of open synovectomy at 2 years in their case series of only six hips. Carl et al observed great to very great functional improvement in 85% of hips at an average of 4 years after open synovectomy for treatment of JRA. The survival rate was 94%, with five (7%) of 65 hips requiring THA during this follow-up period. Similar functional and joint pain improvements also have been reported.
The role of synovectomy obviously becomes limited as disease progression and joint degeneration escalate. Synovectomy frequently becomes only the first of multiple subsequent surgical procedures. Mogensen et al reported that an average of 4.4 surgeries were performed on each patient during a 52-month follow-up period after synovectomy. Risks such as open dislocation also were frequently reported with open synovectomy. The less invasive arthroscopic technique may allow for a more complete synovectomy without these traditionally associated risks.
Release of Soft Tissue Contractures
Soft tissue contractures can result in significant functional impairment. In JRA, contractures about the hip typically lead to a flexed and adducted position. In addition, chronic psoas muscle spasm may accentuate femoral anteversion during skeletal growth. The combination of muscle tone imbalance and increased femoral anteversion often can lead to joint subluxation.
McCullough recommends adductor and psoas tenotomy for fixed flexion contractures 25 degrees or less with an associated adduction contracture or for isolated adduction contracture with lateral femoral head subluxation. Additional anterior capsular releases and synovectomy are recommended for flexion deformities greater than 25 degrees. Short-term functional improvements and pain relief have been reported with such soft tissue procedures in JRA patients. Some authors have even shown sustained beneficial effects after 4 to 5 years of follow-up in terms of pain relief and joint mobility. Poor results from isolated soft tissue release can be expected if advanced degenerative changes are present in the joint. Soft tissue release does not affect radiographic progression of the disease, and more than half of these patients required additional surgical intervention after contracture releases.
Soft tissue contractures about the hip also can be addressed at the time of arthroplasty. Although postoperative motion typically remains limited compared with that achieved after a routine THA, the average improvement tends to improve a patient’s activities of daily living and sitting comfort significantly. However, Scott noted the potential for nerve palsy (e.g., sciatic or femoral) increases with contracture release, especially with concurrent limb lengthening during THA. Although typically transient, such nerve palsies may require a year or more for complete resolution.
Hemiarthroplasty
Hemiarthroplasty has been viewed as a more conservative alternative to THA by preserving pelvic bone stock and thus facilitating future revision. However, hemiarthroplasty has historically been met with relatively modest and transient success in this patient population.
Yun et al reviewed a series of 39 bipolar hemiarthroplasties performed in 24 patients with JRA. Despite early radiographs showing reconstitution of acetabular bone stock after augmentation, progressive resorption and loss of hip center correction were characteristic radiographic findings during the 12 years of follow-up. Significant superomedial component migration resulted in a revision rate of 36% ( Fig. 16-1 ). Rogalski et al reported similar findings of bone graft resorption and progressive superomedial bipolar migration in a group of 24 hemiarthroplasties followed up for 2 years.
