Arthroscopy of any joint is less common in children than in adults because of the preponderance of peri-
articular and growth plate-related injuries that are peculiar to skeletally immature patients. Likewise, when focusing the discussion to arthroscopy of the hip joint, the indications for and outcomes of the procedure are even less well defined than in the adult. In 1977, Gross noted, in his experience with 32 arthro-scopic hip surgeries in children, that the procedure did not seem to more accurately delineate the diagnosis or add to the therapeutic outcome,26 thus quelling early efforts in the application of this technique to young patients. However, since this early report, there have been renewed interest in and enthusiasm toward minimally invasive alternatives to open surgery on the hip in children with a multitude of diagnoses. The following discussion focuses on some of the more common childhood conditions in which hip arthroscopy does potentially play a beneficial role.
Perhaps the most common indication for hip arthros-copy in the pediatric and adolescent population, and certainly the most common indication in our series, has been in cases of Legg-Calve-Perthes disease (LCP), both for diagnosis of severity and the treatment of late sequelae including the removal of loose bodies.27 Suzuki et al. reported on their series of 19 children undergoing diagnostic and operative hip arthroscopy for LCP disease. From this study a new breadth of knowledge has been gained on the gross and histologic pathology of this disease. Among their novel findings were the presence of synovial proliferation in both the ac-etabular fossa and the inner wall of the capsule. They postulate that this mass effect and the presence of hy-pervascularity add to the instability and femoral head coverage problems seen in this condition. Furthermore, the microscopic in vivo anatomy was shown to be that of proliferative hyperplasia and not inflammation. Although lavage was the only therapeutic modality applied at the time of arthroscopy, the authors reported that postoperative range of motion about the hip was significantly increased and pain was decreased.28
Four main sequelae of LCP disease are commonly seen (see Figure 14.1). These include, first, coxa magna, with an enlarged spherical or oval femoral head and relatively normal neck-shaft angles (Figure 14.1A,B). Second, coxa brevis can occur, with associated shortening of the femoral neck, overgrowth of the greater trochanter, and a shortened extremity (Figure 14.1C). Least commonly, osteochondritis dissecans (OCD) may be present, which involves an incomplete healing of the necrotic epiphysis (Figure 14.1D,E). Coxa irregularis is also described, which appears on radiographs as an irregular grooved and incongruent femoral head (Figure 14.1F,G). Bowen and his group described the arthroscopic treatment of OCD of the hip following Perthes' disease in a review of 14 pa tients with 15 hips involved. The standard treatment of this condition includes observation, bed rest, and activity modification with nonsteroidal antiinflam-matory drugs. In this series, 5 patients underwent ar-throscopic evaluation of the extent of degenerative disease; removal of the necrotic segment was attempted in 4, and successful in 3 patients. Femoral valgus osteotomy was performed in 2 patients based on ar-throscopic findings, and both procedures were con sidered successful. This review has served to expand the indications and therapeutic validity for hip arthroscopy in LCP.29
Juvenile Rheumatoid Arthritis/ Juvenile Chronic Arthritis
As the field of minimally invasive surgery including arthroscopy has advanced, so has the enthusiasm for
FIGURE 14.1. Late sequelae of Legg-Calve-Perthes (LCP) disease. (A) Coxa magna: enlarged femoral head with lack of lateral acetabular coverage is shown. A relatively normal neck-shaft angle is preserved. (B) Coxa magna radiograph: anteroposterior (AP) radiograph of hip demonstrating the classic findings of coxa magna, enlarged oval femoral head. (C) Coxa breva: shortened femoral head and overgrowth of the greater trochanter are shown. (D| Osteochondritis dissecans (OCD): incomplete healing of the femoral epiph-ysis with entrapment of a fragment of necrotic bone within the femoral head. (E) OCD radiograph: clinical radiograph demonstrating a necrotic focus of bone entrapped in the femoral head, likely a result of incomplete healing of the necrotic epiphysis during LCP. (F) Coxa irregularis: an irregular and grooved femoral head is shown. Frequently this leads to advanced degenerative changes in the lateral and superior weight-bearing portions of the acetabulum. (G) Coxa irregularis radiograph: frog leg lateral radiograph demonstrates an irregular femoral head nearing the end of the healing phase of the disease; this is likely to result in coxa irregularis.
the application of arthroscopy to more unusual and less well understood joints such as the pediatric hip joint. Examples of this evolution include two more favorable series published in 1981 and 1986 reviewing the use of arthroscopy in juvenile chronic arthritis. Both reports tout hip arthroscopy as being valuable in diagnosing the extent of cartilage damage and the severity of synovitis, concluding that the procedure has value in the diagnosis of this condition.30,31 Furthermore, Blitzer, in his series of patients treated with hip arthroscopy for septic arthritis, diagnosed one of his patients with JRA, adding to the diagnostic validity of this procedure.7 Synovial biopsy of the hip joint, without the potential of avascular necrosis associated with open arthrotomy, is also a valuable and easily performed procedure in the workup of a patient with suspected JRA to evaluate the polyarticular nature of the disease. On a less positive note, the therapeutic efficacy of arthroscopic synovectomy for rheumatoid arthritis (RA) of the hip can be questioned based on a report by Ide et al. They performed arthroscopic syn-ovectomy in three cases (six hips) and noted that there was no significant recovery of motion and that the pain relief was only temporary. However, all their patients were adults with stage III RA and severe cartilage damage. They concluded that the procedure would have been more helpful if it was performed earlier before the articular cartilage was destroyed.32 It is likely that early in the course of JRA, when it affects the hip joint, arthroscopic synovectomy and debride-ment may provide improved results over those seen in the adult population.
Arthroscopy for slipped capital femoral epiphysis (SCFE) was reviewed in 1992 by Futami et al. Ar-throscopy was performed to investigate the magnitude of articular cartilage and labral injury and to decompress the hematoma resulting from the fracture. In their review of five hips, they observed three associated labral injuries in the posterolateral portion of the labrum.33 This finding was in contrast to the reports by Suzuki and Ikeda, who found labral tears in the posterosuperior position in young patients with occult hip pain. Arthroscopy also showed erosion of the ac-etabular cartilage anterosuperiorly, a transverse cleft on the anterior surface of the femoral head, and meta-physeal cartilage damage. They believed these findings corresponded to joint cartilage being crushed between the acetabulum and the femoral head and friction on the joint cartilage during joint motion after the slippage occurs.2,28 From the information gained by preoperative diagnostic arthroscopy, Futami et al. concluded that this knowledge should be of great benefit in the therapy for and interpretation of the pathology in SCFE. They further added that evacua tion of the resultant hematoma by arthroscopic lavage effectively reduces pain and may permit earlier postoperative motion and weight bearing.33
Treatment of early symptomatic developmental dys-plasia of the hip centers on obtaining adequate coverage for the femoral head. As the femoral head sub-luxates laterally, contact pressures on the acetabular and, subsequently, femoral side of the joint increase to critical levels, eventually resulting in degenerative arthritis. Multiple procedures in the child have been described and validated in the literature for obtaining this coverage, including both femoral and acetabular osteotomies. Most series support the use of pelvic or femoral osteotomy in the child both to prevent this end-stage disease and to encourage the normal development of the acetabulum and femoral head. However, when an older child or young adult presents with pain attributable to DDH, the indications for and results of hip osteotomies are less well defined. Even in the best of hands, thee procedures can have unpredictable results.
In the adolescent or young adult who presents with hip pain and a diagnosis of DDH, labral pathology has been shown to be the first stage of the development of degenerative arthritis. Klaue et al. confirmed that "acetabular rim syndrome" is a precursor to the development of secondary osteoarthritis in these pa-tients.34 It is not yet known if direct treatment of these labral injuries can change the natural history of the disease, but it has been shown that arthroscopic resection of the torn labrum in these patients provides symptomatic relief.35 Noguchi et al. demonstrated the efficacy of using the arthroscope to determine the amount of degenerative changes in the hip joint before performing osteotomies. The results of osteotomy procedures are known to be worse in patients with degenerative changes, and these changes may not be easily visualized radiographically. However, arthroscopic examination can show the extent of acetabular and femoral head degenerative changes and could be used as a guide to determining appropriate candidates for osteotomy.35
In the many series of athletic hip injuries reported in the current literature, seldom is the role of arthros-copy of the hip in pediatric and adolescent patients addressed. In Dorfmann's large series, the age range of patients was from 14 to 81 years. However, no specific mention of the mechanism of injury or pathology is noted for the younger patients.9 Similarly, Schindler et al., in their comprehensive article, do not address the issue of the young athlete.13
In the last several years, only a few pediatric cases have been described specifically addressing the role of arthroscopy for hip pain associated with an injury during sporting activity. In a review by Ikeda et al., three patients, aged 15, 15, and 16 years, had acute onset of pain related to athletic participation. The first patient was injured during a sprinting event, the second was injured while competing in rugby football, and the last had sudden onset of pain while playing volleyball. All three patients were diagnosed arthroscopically as having tears of the acetabular labrum.2 In this series, attempts at resection of the tear were not undertaken; however, multiple reports have described techniques for doing so.21,23,24,36-38 The authors supported previous findings of a posterosuperior location of the tear, thought to be secondary to anatomic vulnerability to injury in that location.11,23,39 It can be concluded that, similar to the glenoid labrum in the athlete, the ac-etabular labrum can be adequately examined and tears treated using arthroscopic techniques.
Hip Arthroscopy for Pediatric and Adolescent Pyarthrosis
One group of pediatric patients for which hip ar-throscopy may provide effective treatment is those patients with a suspected diagnosis of pyarthrosis. This potentially catastrophic condition can be evaluated with laboratory studies including leukocyte count and erythrocyte sedimentation rate. Of these, the eryth-rocyte sedimentation rate appears to be the most sensitive and specific.40 Although ultrasonic-guided aspiration of the hip joint may provide the definitive diagnosis, routine radiographs can rule out many of the possible etiologies, such as DDH, LCP, and SCFE, in children with normal laboratory results.41 Arthro-scopic washout of an infected hip has been reported in several studies in both the child and adult, and this procedure, which spares the child the possible iatro-genic problems associated with open washout, is becoming more routinely used.
Two series in the literature show a definite role for arthroscopic management of hip sepsis in the pediatric patient. Blitzer described the use of the arthroscope for the treatment of five patients with a presumed diagnosis of septic arthritis. The author cites the potential complications of open arthrotomy to be aseptic necrosis of the femoral head, subsequent dislocation of the hip, the cosmetic appearance of the standard open procedure, and prolongation of hospital stay. With the high index of suspicion necessary in cases of possible hip sepsis, and the extensive differential diagnoses, including transient synovitis, JRA, and peri-acetabular or pelvic abscesses or myositis, a certain number of pediatric patients would undergo unnecessary arthrotomy if arthroscopy is not used. Blitzer further concludes that, in a patient who is "old enough"
to be safely arthroscoped, the procedure is beneficial. This vague definition of age, however, does not provide the reader with a true definition of the appropriate candidate for arthroscopic lavage.7 A more accurate age limit for arthroscopic treatment of hip pyarthrosis is provided by Chung et al., who in their series report the safe application of this procedure in patients as young as 2.4 years. They conclude that ar-throscopic lavage and synovectomy are safe and effective in patients between the ages of 2 and 7 years, that the associated morbidity is low and the recovery of mobility rapid. The use of the arthroscope as a large-bore instrument to deliver a high-volume lavage has the added benefit of direct visualization of clot and infected joint debris.19 Although arthroscopic debride-ment does not allow for direct identification of or treatment for foci of osteomyelitis, Chung et al. found that this did not influence the success of treatment. Two of their nine patients had focal metaphyseal ra-diodensities that resolved after arthroscopic treatment and routine antibiotics.19 As mentioned, arthroscopic lavage and debridement also provide synovium for tissue diagnosis in equivocal cases in which JRA or transient synovitis may be the underlying cause of the hip pain and abnormal laboratory values.
Benign tumors about the hip are not uncommon in childhood, and some present in the intracapsular location, which may be amenable to arthroscopic management. Khapchik et al. reported on two cases of os-teoid osteoma, a common benign tumor presenting in the first three decades of life, managed with arthro-scopic excision. They noted that the procedure was relatively easy and had the added benefit of enabling the surgeon to obtain a biopsy specimen before treatment, something that is not available using percutaneous ablation techniques.42 Thompson and Wooward described the use of the arthroscope in aiding the treatment of a chondroblastoma of the femoral head.43 The obvious benefits of using minimally invasive techniques to treat intracapsular benign tumors in children and young adults are the ability to obtain a tissue diagnosis and the reduced morbidity and rapid functional recovery possible. Furthermore, arthros-copy would not complicate a subsequent open resection for the treatment of a recurrence, if it should occur. One can envision future endeavors to treat childhood benign tumors of the proximal femur such as unicameral bone cysts arthroscopically. Another tumor, of sorts, that has been successfully treated arthro-scopically is synovial chondromatosis of the hip. In the prospective analysis by Byrd and Jones, they described treating a patient with synovial chondro-matosis of the hip successfully with the arthroscope. Of particular interest is that at the time of a second procedure for the excision of heterotopic ossification of the soft tissues, no recurrent loose bodies were noted.44
We have treated 17 patients 18 years of age or younger over the past several years at our institution with arthroscopic surgery of the hip. Patient age ranged from 11 to 18 years. Diagnostic evaluation included plain radiographs of the pelvis and affected hip in each case. Supplemental imaging studies such as magnetic resonance imaging (MRI) or computed tomography (CT) scans were either obtained by the referring physician or performed at our institution. Physical examinations, including range of motion and the presence of reproducible mechanical symptoms, were also reviewed. Mechanical symptoms, in this group of patients, were defined as a subjective complaint of clicking, locking, popping, or giving way documented during routine history taking and the presence of reproducible pain with provocative maneuvers. In the routine treatment of LCP disease, which is a common diagnosis treated at our institution, we use arthros-copy only for those patients with mechanical symptoms and radiographic evidence of treatable intraar-ticular pathology. Findings of OCD, chondral injury, or labral pathology in these patients are thought to be good indications for surgical intervention. Most pedi-atric patients presenting with hip pathology are not offered arthroscopic surgery because their conditions are thought not to be amenable to this type of treatment. For example, a 14-year-old cheerleader with Ehlers-Danlos syndrome and recurrent painful popping in the hip, generalized ligamentous laxity, and a normal MRI arthrogram was excluded from operative treatment and is being followed to skeletal maturity.
Table 14.2 outlines the indications for arthroscopy and the treatments performed in our patients.
Hip arthroscopy was performed typically on an outpatient basis. The patient was positioned supine on a standard fracture table with a traction device and ar-throscopy performed in a fashion similar to that described by Byrd and others.1'9'15'17'45'46 Both regional and general anesthesia techniques were used' depending on patient and anesthesia preference. Para-trochanteric and anterior portals were created under direct fluoroscopic guidance. An 18-gauge angiocath needle was used to localize and distend the joint' with release of the vacuum pressure. Between 5 and 10 mm of joint distraction was then achieved through traction on the extremity and was confirmed by fluoroscopy.9'14'17'38'46 Careful patient positioning and padding of the perineal post was used to avoid possible neurologic complications. Portals were then dilated over a guidewire' and either a 30- or 70-degree arthroscope was introduced into the joint (Figure 14.2). Standard arthroscopic instruments were then used as needed for chondral and labral debridement' synovectomy' and removal of loose bodies.14
All these patients had a diagnosis of hip pain persisting for more than 3 months that had not responded to appropriate nonoperative measures. Three patients had acetabular labral tears addressed at arthroscopy following motor vehicle accidents and dashboard-type injuries. One of these patients had underlying developmental dysplasia of the hip' a labral tear in the su-peroanterior location (as described for DDH)' but no evidence of degenerative joint disease was noted. The second patient sustained a femoral neck fracture at the time of injury and had continued pain in the affected hip for 48 months before arthroscopy. An unstable chondral lesion and a labral tear were identified and treated arthroscopically with 24 months of relief of pain. This patient did require repeat arthroscopy of
TABLE 14.2. Indications for Hip Arthroscopy and Therapeutic Procedures Performed: The Author's Experience.
Number of cases
Removal loose body Debridement chondral injury Partial limbectomy Removal OCD
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