At present, hip arthroplasty is one of the most successful medical procedures available to the world, in terms of pain relief, return to function, and improvement in the quality of life for patients with hip arthritis. This article discusses end-stage hip pathologic conditions in pediatric patients, pros and cons of total hip arthroplasty and hip resurfacing arthroplasty in adolescents and very young adults, and special issues that should be considered when treating these young patients.
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Pediatric hip disorders can lead to early end-stage arthritis of the hip.
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Both total hip arthroplasty and hip resurfacing arthroplasty are options for the surgical treatment of hip arthritis in adolescents and young adults.
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Early reports comparing the 2 treatment options are difficult to interpret, and drawing definitive conclusions is difficult because they do not have sufficient evidence.
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Issues related to metal ions from metal-on-metal bearing surfaces should be considered.
Introduction
At present, hip arthroplasty is one of the most successful medical procedures available to the world, in terms of pain relief, return to function, and improvement in the quality of life for patients with hip arthritis. However, the success rate of total hip arthroplasty (THA) is noticeably lower in younger and more active patients. Problems of prosthetic loosening, wear, osteolysis, and a shortening prosthetic life span have all been documented with higher frequency in younger patients.
The indications for hip arthroplasty in the very young adult are the same as that in older patients: significant pain, decreased function, and a poor quality of life because of hip arthritis. However, because of the relatively higher risks involved with the longevity of the prosthesis, both patients and surgeons alike are cautious before proceeding to arthroplasty in such young patients. Furthermore, these surgical procedures are often technically demanding because of underlying severe deformity of both the femur and pelvis and previous surgery.
Although arthroplasty is never performed cavalierly in pediatric patients and very young adults (younger than 30 years), pathologic conditions may be so severe that arthroplasty or arthrodesis is the only viable option. At present, hip arthrodesis is less commonly performed because of advances in arthroplasty techniques and materials. Yet, at times, arthrodesis may be considered in the very young patient. The general thought is that hip arthrodesis gives a good outcome with a near normal gait pattern. However, there have been no studies that have investigated the functional activities of daily living, which most likely would be severely limited by hip arthrodesis. There are no contemporary series that discuss and compare hip arthrodesis to THA or hip resurfacing arthroplasty (HRA). An active patient does not often accept arthrodesis as a viable treatment option.
Even with the known difficulties, several series have reported great success with THA in young patients. Previous studies on the clinical outcome or cost-effectiveness of THA have objectively rated it as one of the most successful interventions in modern day medicine. Uncemented components are the mainstay in most arthroplasty cases today, and clinical results have shown excellent longevity, with a 10-year survivorship of more than 95% documented in multiple reports.
HRA has recently been reintroduced as a possible alternative for young active patients with hip arthritis. Original reports from the developers of some of the newer HRA systems have shown excellent midterm results, with a 10-year survivorship of 98%. Furthermore, motion analysis laboratory studies have suggested more normal function for patients receiving HRA in comparison with patients receiving traditional THA. However, recent reports, in the national joint registries, of higher failure rates in some HRA systems have tempered some of the initial excitement for HRA. The higher revision rates coupled with concerns about metal ions, metal hypersensitivity reactions, and pseudotumors have thrown the future of resurfacing into ambiguity. One of the main criticisms of HRA is that it is much more technically demanding than THA, with a significantly steep learning curve. Nevertheless, many investigators maintain that HRA is an excellent treatment option for the very active and very young patient with end-stage hip disease.
The purpose of this article is to discuss end-stage hip pathologic conditions in pediatric and adolescent patients and the pros and cons of THA and HRA in adolescents and the very young adult and to put forward special issues that should be considered when treating these young patients.
Etiology of hip arthritis in pediatric patients and young adults
Hip arthritis is relatively rare in pediatric patients, adolescents, and adults younger than 40 years. However, several pathologic conditions predispose certain patients to have a higher risk of joint deterioration than the general population. Most experts in adult hip arthritis believe that osteoarthritis of the hip in adults mainly occurs from a more definitive specific pathologic condition that is responsible for the arthritis. Some of the more common pathologies encountered in the very young adult patient include developmental dysplasia of the hip (DDH), femoral acetabular impingement (FAI), Perthes disease, slipped capital femoral epiphysis (SCFE), avascular necrosis (AVN), and inflammatory arthritis. (Please note: THA and DDH, FAI, AVN, and inflammatory arthritis have been discussed elsewhere in this issue, and the technical details of surgical technique for these pathologic conditions are not discussed in this article.)
Etiology of hip arthritis in pediatric patients and young adults
Hip arthritis is relatively rare in pediatric patients, adolescents, and adults younger than 40 years. However, several pathologic conditions predispose certain patients to have a higher risk of joint deterioration than the general population. Most experts in adult hip arthritis believe that osteoarthritis of the hip in adults mainly occurs from a more definitive specific pathologic condition that is responsible for the arthritis. Some of the more common pathologies encountered in the very young adult patient include developmental dysplasia of the hip (DDH), femoral acetabular impingement (FAI), Perthes disease, slipped capital femoral epiphysis (SCFE), avascular necrosis (AVN), and inflammatory arthritis. (Please note: THA and DDH, FAI, AVN, and inflammatory arthritis have been discussed elsewhere in this issue, and the technical details of surgical technique for these pathologic conditions are not discussed in this article.)
DDH
From infancy to adulthood, DDH describes a wide spectrum of pathologic conditions in which the hip joint itself has abnormal morphology that leads to pain and dysfunction and ultimately, in many cases, joint replacement ( Fig. 1 ). Newborn screening and early treatment strategies, such as the Pavlik harness, have reduced the cases of untreated hip dysplasia. In cases of hip dysplasia that go undetected in newborn screening or are resistant to harness therapy, treatment with closed/open reduction and pelvic osteotomies is effective in reducing the long-term sequelae of DDH. The advent of periacetabular osteotomy has improved nonarthroplasty outcomes in the patient with symptomatic DDH in adolescence and young adulthood. The long-term outcome of severe and undertreated DDH is significant hip arthritis for which the appropriate treatment is arthroplasty.
Very young patients with neuromuscular hip dysplasia may progress sooner to end-stage hip arthritis than to DDH. Patients with cerebral palsy, Down syndrome, and other neuromuscular diseases often have severe hip dysplasia. Hip arthroplasty carries a high risk of complications in these disorders, including instability, infection, and loosening. Yet in the carefully selected patient, arthroplasty may be a solution to give these patients a better quality of life ( Fig. 2 ).
FAI
Advances in the knowledge of hip pathophysiology have increased the understanding of how FAI leads to hip arthritis. In the pediatric patient, FAI can occur from several primary pathologic conditions, such as Perthes disease or SCFE. Idiopathic FAI results from 2 primary mechanisms: cam and pincer impingement. If left untreated, FAI can lead to cartilage delamination, overloading of the joint cartilage, and, ultimately, end-stage arthritis. Young adults with FAI now have effective treatment options in the form of surgical hip dislocation and femoral head osteoplasty, which can safely improve the biomechanics of the joint with low risks of iatrogenic AVN.
Perthes disease
Perthes disease is a poorly understood disorder that is associated with a disruption of the blood supply to the growing femoral head in children. The characteristic sequence of epiphyseal growth retardation, sclerosis, fragmentation, and reossification leads to coxa magna and both femoral and acetabular deformity, which often becomes symptomatic in adolescence and young adulthood. The efficacy of surgical treatment in the pediatric patient is still under debate. Adults with early onset symptoms may benefit from FAI treatment techniques. Severe deformity results in the need for arthroplasty in early adulthood.
SCFE
Many factors are thought to contribute to the pathophysiology of SCFE, including body habitus and adolescent obesity, hormonal disorders, and mechanical factors. The incidence varies widely across different regions, and this regional variation is largely unexplained. In situ pinning has been the mainstay for the treatment of children with SCFE, and for mild to moderate cases, this treatment seems to stabilize the deformity and lead to relatively normal hip function. However, patients with more severe slips and those who progress on to AVN develop early osteoarthritis requiring arthroplasty. As in other areas of hip pathology in the adolescent and young adult, newer treatment options have been designed with the aim of increasing the longevity of these slipped hips. Acute surgical hip dislocation and open reduction of SCFE have been reported in small series, which have resulted in excellent resolution of the deformity seemingly without an increase in the progression to AVN from the baseline risk that SCFE naturally brings. FAI techniques can also be used in the chronic setting, with the goal being to decrease impingement that leads to chondral damage and hip arthritis.
AVN
AVN, also known as osteonecrosis, of the hip comes from a wide range of primary pathologic conditions. AVN typically affects young adults aged 30 to 40 years but can affect pediatric patients in their teenage years. Exposure to several risk factors can lead to AVN, including sickle cell disease, thrombophilia, use of alcohol and corticosteroids, and myeloproliferative disorders, such as leukemia or Gaucher disease. AVN from these latter disorders can come from the disease process itself or the treatments, such as chemotherapy and chronic use of steroids. Early stages of AVN can be effectively treated with nonarthroplasty techniques, such as core decompression or vascularized free fibular implantation. Larger lesions and more advanced collapse can only be effectively treated with arthoplasty.
Others
The most common pathologic conditions causing end-stage hip disease in an adolescent or young adult have been discussed earlier. However, there are several other disease processes that can also destroy the hip joint, necessitating arthroplasty. Inflammatory arthropathies, including rheumatoid arthritis and ankylosing spondylitis, can lead to hip pathologic conditions requiring arthroplasty at a young age. Idiopathic chondrolysis can cause rapid destruction of the hip cartilage without a specific known causative factor. Posttraumatic arthritis can occur after high-energy trauma, such as hip dislocation, acetabular fractures, or femoral head fractures ( Fig. 3 ). Infections can also cause significant destruction of the cartilage. A previously neglected or undertreated septic arthritis can leave children with a severely pathologic hip joint for the remainder of their life ( Fig. 4 ).
Related posts:
Surgery for Residual Femoral Deformity in Adolescents
Periacetabular Osteotomy for Hip Preservation
Technical Considerations in Total Hip Arthroplasty After Femoral and Periacetabular Osteotomies
Strategies to Improve Nonoperative Childhood Management
Periacetabular Osteotomy for Hip Preservation
Technical Considerations in Total Hip Arthroplasty After Femoral and Periacetabular Osteotomies
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