Arthroscopic Management of Pediatric Hip Disease

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CHAPTER 25 Arthroscopic Management of Pediatric Hip Disease

Yi-Meng Yen, Mininder S. Kocher

Introduction

Injuries of the hip and pelvis in the pediatric population are increasing and receiving more attention. The majority of injuries are soft-tissue or apophyseal injuries that heal with nonoperative treatment. However, with the advent of hip arthroscopy and the development of more advanced imaging of the hip that involves magnetic resonance arthrography, internal derangements of the hip (e.g., labral tears, loose bodies, chondral injuries) are being diagnosed and treated with increased frequency. Hip arthroscopy has obvious advantages as compared with arthrotomy and surgical dislocation for the pediatric population. It is significantly less invasive than arthrotomy, and it allows for a quicker recovery and a sooner return to activities. Most of the experience in hip arthroscopy has been with hip disorders in adults; the role of hip arthroscopy for children and adolescents has been less well characterized.

Historically, arthroscopy of the hip in the pediatric population was used as a diagnostic and therapeutic tool for slipped capital femoral epiphysis, septic arthritis, and various arthropathies. The most common indication has been in cases of Legg-Calvé-Perthes disease, both for the diagnosis of severity and treatment, including the removal of loose bodies. In a review of 24 hip arthroscopies performed in 21 patients between the ages of 11 and 21 years old, Schindler and colleagues concluded that hip arthroscopy was effective for synovial biopsy and loose-body removal; however, as a diagnostic procedure, the arthroscopy failed to correlate with the presumptive cause of symptoms in 11 hips (46%). In many of the general series reported in the current literature, the role of hip arthroscopy for pediatric and adolescent athletes is rarely addressed. As our understanding of the mechanisms and anatomic abnormalities of hip pathology increases, the role of hip arthroscopy for the pediatric population will continue to expand.

Brief history and physical examination

Pediatric and adolescent patients are different from adults in that they frequently do not complain about hip pain. It is common for hip pathology to be discovered only after the examination of a young patient who complains of knee pain: up to a quarter of patients with stable slipped capital femoral epiphysis (SCFE) report knee pain. Another frequent presentation is in the limping child who has not experienced any known injury. As with any orthopedic patient, a detailed history is mandatory. On average, less than half of patients can recall a traumatic event that led to the injury. Running, jumping, and kicking activities are frequently involved in labral pathology, and patients often report an acute twisting injury. A gradual history of pain is frequently more common. Subjective complaints of catching, locking, and giving way point to mechanical symptoms that can benefit from surgical intervention. These symptoms should be carefully distinguished from popping or snapping sensations, which may indicate extra-articular pathology (e.g., psoas tendon bursitis, coxa saltans externa or interna).

The physical examination of the hip begins with the examination of the range of motion. A decreased range of motion as compared with the contralateral unaffected hip is a useful sign of hip pathology. Loss of flexion and internal rotation are usually the earliest signs in these patients. Hip contractures should be examined, and leg lengths and pelvic obliquity should be noted. An impingement test with flexion, adduction, and internal rotation appears to be predictive of intra-articular pathology. An examination of the low back, including straight-leg raising, should be conducted to rule out any contribution of the spine.

Imaging and diagnostic studies

Plain-film radiography remains the primary screening tool, because it is widely available and relatively inexpensive; however, it must be performed properly. An anteroposterior radiograph with cross-table lateral views of the hips should be obtained. The anteroposterior radiograph is used to assess dysplasia and acetabular version. There should not be any excessive tilt of the pelvis, and, in general, the tip of the coccyx should be approximately 2 cm above the pubis. The cross-table lateral view with the hip in internal rotation is useful to determine the presence of a cam-type lesion in a patient with femoroacetabular impingement. To assess intra-articular pathology (e.g., labral or ligamentum teres tears, cartilage pathology), a unilateral magnetic resonance image with intra-articular gadolinium is used; in some centers, an “optimized nonarthrogram protocol” may be as accurate as a magnetic resonance image with gadolinium that includes the use of high resolution and a fast-spin-echo sequence. Occasionally a computed tomography scan can be used to further define the version of the femur and acetabulum and to visualize loose bony fragments and fracture. However, radiation doses to the pelvic organs can be substantial, and computed tomography should be used sparingly in the pediatric population.

Surgical technique

Hip arthroscopy can be performed with the patient in the supine or lateral decubitus position. Both positions allow for adequate visualization and positioning, and the one that is used is based on surgeon preference. We perform hip arthroscopy with the patient in the supine position, and it is generally performed as an outpatient procedure for the pediatric population. General anesthesia is used with muscle relaxation, although supplementation with regional anesthesia may be used, depending on the anesthesia available and patient preference. A standard fracture table or a specialized hip-scope table is used with a traction device and a large padded perineal post (Figure 25-1). The affected leg is prepped and draped along with a C-arm (Figure 25-2). The nonoperated side is placed in approximately 30 degrees of abduction, and firm traction is applied to that side so that the patient remains firmly against the perineal post. The operated leg is placed in neutral abduction to maintain a constant relationship between the topographic landmarks and the joint. A slight 10 degrees of flexion is used to relax the capsule; however, excessive flexion and traction can place tension on the sciatic nerve. Maximal internal rotation is used to make the femoral neck parallel with the floor. Traction is applied to achieve joint distraction between 5 mm and 10 mm, and this is confirmed by fluoroscopy; this will typically demonstrate the “vacuum sign” when viewed with the use of fluoroscopy. In general, approximately 50 lb to 75 lb of force is needed to distract a joint. The goals are to use the minimal force necessary to achieve distraction and to keep traction times as brief as possible (in general, less than 2 hours is considered optimal).

Figure 25–1 A, Standard table with special hip-scope extension. B, Large perineal post with the operative leg in a neutral position, slightly flexed, and internally rotated.

Figure 25–2 A patient draped with a C-arm fluoroscope in position.

Portals

Two to three operating portals are typically used. The anterolateral and posterolateral portals are placed at the superior margin of the greater trochanter at the anterior and posterior borders (Figure 25-3). The mid-anterior portal is made by first drawing a sagittal line from the anterosuperior iliac spine and another line at the anterolateral portal; a sagittal line is then drawn equidistant to these two lines. The entry point for the mid-anterior portal is approximately 45 degrees from the anterolateral portal on the middle sagittal line. With careful attention paid to these landmarks, the portals can be safely made away from neurovascular structures. The lateral femoral cutaneous nerve typically lies just medial to the anterosuperior iliac spine; the femoral nerve and artery are even more medial.

Figure 25–3 The locations of the arthroscopy portals. The greater trochanter is outlined, and, with the foot internally rotated, the neck of the femur is parallel to the floor. The locations of the posterolateral and anterolateral portals are on the posterior and anterior borders of the greater trochanter. The mid-anterior portal is established by drawing a line parallel to the anterior border of the greater trochanter halfway between the border and the anterosuperior iliac spine (ASIS). A line 45 degrees from the anterolateral portal is drawn, and the intersection of the two lines is the location of the mid-anterior portal.

After traction is applied, a spinal needle is placed from the anterolateral position under fluoroscopic control, and the joint is distended with fluid. Care must be taken to ensure that the labrum is not perforated and that the femoral head articular surface is not disturbed. A Nitinol wire is inserted through the spinal needle, and the camera trochar is inserted with the use of a twisting motion (never a forceful push). With the use of a 70-degree arthroscope, the mid-anterior and posterolateral portals are then established under direct visualization. A fluoroscope can also be used to help with the establishment of the portals.

The peripheral compartment is entered by releasing traction with the arthroscopic instruments out of the joint but remaining intracapsular. The hip is flexed to approximately 30 degrees to 45 degrees to relax the capsule. The anterolateral portal and the mid-anterior portal can be used, or an ancillary portal approximately 5 cm distal to the anterolateral portal can be established under direct visualization.

Diagnostic and Surgical Arthroscopy

A diagnostic arthroscopy can be performed with the use of a combination of 70-degree and 30-degree scopes. Alternatively, an arthroscopic blade can be used to perform an arthrotomy of the hip capsule from the mid-anterior portal to the anterolateral portal. This provides extensive maneuverability within the joint.

Loose bodies still represent the clearest indication for hip arthroscopy. Most of the problematic loose bodies are intra-articular and can be addressed with standard arthroscopic methods (Figure 25-4), and many can be debrided with shavers or flushed out through large-diameter cannulas. Both the intra-articular and peripheral compartments must be addressed, because loose bodies can easily hide within the peripheral joint. Large fragments frequently need to be morselized or removed freehand with sturdy graspers. If the surgeon is removing pieces in a freehand manner, the portal may need to be enlarged and the capsule further incised to prevent the loss of the fragment in the capsule or the subcutaneous tissue.

Figure 25–4 A, Radiograph of a patient with spondyloepiphyseal dysplasia and right hip pain. B, The removal of a loose body. Note the chondral damage to the femoral head.

Labral pathology represents one of the most common reasons that athletes undergo hip arthroscopy. Labrum degeneration can occur as part of the aging process, and evidence of labral pathology exists in patients without symptoms. In general, pediatric patients experience more traumatic labral tears, but conditions such as femoroacetabular impingement have been recognized to predispose even young individuals to labral tearing. Labral tears can be addressed in a way that is similar to that of a meniscus in the knee. The goal is to remove diseased labrum to a stable rim of healthy tissue (Figure 25-5). Debridement can be performed with an arthroscopic shaver or thermal ablation with a flexible wand; however, care should be taken with thermal devices to avoid deep heat penetration. The evolution of debridement of the labrum has been to repair it.

Figure 25–5 A, Magnetic resonance arthrogram of a labral tear. White arrow shows contrast behind the labrum indicative of a labral tear. B1, B2, Fraying of the labrum. B3, A thermal ablation device; B4, Debridement of the labrum with a shaver.

Currently, labral repair of the hip resembles that of the shoulder. Occasionally the labral tissue must be partially detached from the chondrolabral junction that surrounds the original tear to obtain adequate exposure for the trimming of the acetabular rim. The center-edge angle should be known preoperatively, and the version of the acetabulum should be assessed. For cases in which there is normal anteversion of the acetabular cup, the bony area of labral detachment on the acetabular rim should be roughened with a rasp or an arthroscopic burr to ensure an adequate bony bed for the reattachment of the labrum. For cases in which there is protrusio or acetabular retroversion, the rim of the acetabulum should be trimmed with the arthroscopic burr. After the bony bed is prepared, suture anchors should be inserted into the rim, with care taken not to pierce the acetabular cartilage. The concavity of the acetabulum can make this difficult, and fluoroscopy can be used to help with anchor placement. The sutures can be looped around the labrum or placed through the labrum, and the knot should be placed on the capsular side. Depending on the size of the tear and if further detachment of the labrum is necessary, we use between one and three anchors.

Special attention should be paid to the articular cartilage around the chondrolabral junction. The extent of damage to this area may play a role in the eventual clinical response to debridement. If this area contains a chondral flap, the flap should be debrided to stable edges, and a microfracture should be performed for grade IV articular lesions. Chondroplasty can be performed with a curved arthroscopic shaver to negotiate the convex and concave surfaces of the hip joint. Radiofrequency devices with flexible wands can be useful as well, but, again, great care should be taken to avoid heat penetration of the surrounding viable chondrocytes.

Ligamentum tears can also be debrided with an arthroscopic shaver or a radiofrequency thermal probe. Access to the ligamentum is typically easiest through the mid-anterior portal, and external rotation of the hip can also help to bring the ligamentum into view. Excessive debridement of the ligamentum should be avoided because of the potential to damage the blood supply to the femoral head in pediatric patients.

Synovitis frequently exists in the joint in response to other intra-articular pathology. A complete synovectomy cannot be performed, but the majority of inflamed synovial tissue can be removed with an arthroscopic shaver and radiofrequency ablation. For primary synovial disease, arthroscopy of both the intra-articular and peripheral compartments is necessary.

Peripheral Compartment

After the work on the intra-articular side is completed, traction is released, and the hip is flexed to approximately 30 degrees to 45 degrees if surgery is to continue in the peripheral compartment. For synovial disease and loose-body removal, this compartment must be checked thoroughly. For patients with femoroacetabular impingement, the cam lesion can be addressed arthroscopically (Figure 25-6). Beginning with the arthroscope in the mid-anterior portal, the lateral edge of the cam lesion can be removed with an arthroscopic burr. Care must be taken not to remove too much bone and cartilage. The resection should begin above the lateral retinacular vessels and proceed medially across the neck; over-resection may predispose the patient to a femoral neck fracture. In the pediatric population, care should be taken not to disrupt the physis; localization with fluoroscopy may be necessary during the osteoplasty procedure.

Figure 25–6 A, Radiograph of an adolescent patient with femoroacetabular impingement and left hip pain. B1, Entry into the peripheral compartment with the hip flexed at 30 degrees. Note the flattened head–neck offset. B2, B3, Recontouring of the femoral head–neck junction with a 5.5 mm arthroscopic burr.

Closure

The wounds are closed with 2-0 Vicryl sutures subcutaneously and 3-0 nylon sutures in a mattress fashion for the skin. Alternatively, 3-0 Monocryl sutures in a buried subcuticular fashion can be used for the skin. Approximately 9 cc of 0.5% Marcaine and 40 mg of Depomedrol is injected into the hip joint before closure.

Technical Pearls

• Traction: Minimize traction time to less than 2 hours. Patients with an intact labrum may require more force to distract the joint. The use of muscle relaxation by anesthesiologists can help with the distraction of the joint.

• Entry: Fluoroscopy aids in the establishment of arthroscopic portals. Great care should be taken not to damage the articular cartilage during entry. The twisting of the cannula should be used instead of forceful pressure to prevent plunging into the joint. The direct visualization of other portals is useful to avoid iatrogenic injury.

• Visualization: Delay the inflow of saline until the outflow portal is established. A 70-degree scope provides the best visualization of the joint as a result of the concavity of the surfaces. A thorough hip capsulotomy allows for complete access to the joint.

• Joint work: The use of curved instruments, flexible tools, and slotted cannulas helps with joint entry and with the accessibility of different areas of the joint.

Postoperative rehabilitation

The goal of rehabilitation is to return the patient to a preinjury level of activity. The first phase of rehabilitation involves protecting the repaired tissues while restoring hip motion and decreasing scarring. Patients are placed on crutches and allowed to be toe-touch weight bearing for approximately 2 weeks. If the patients had a microfracture procedure performed, they are made toe-touch weight bearing for 6 weeks. Gentle range-of-motion exercises are begun with a continuous passive motion machine, passive range-of-motion exercises, and stationary bicycling. If a labral repair is performed, we restrict external rotation and adduction for the first 2 weeks. Early passive range-of-motion exercises emphasize internal rotation and flexion, and isometric strengthening is begun for the gluteals, the quadriceps, the hamstrings, and the transverse abdominals. A continuous passive motion device (CPM) is used for 4 weeks. Approximately 6 weeks postoperatively, full range of motion should be achieved, and strengthening exercises can be started. Sport-specific training usually begins about 3 months postoperatively.

Results

There have been relatively few results published regarding the use of hip arthroscopy for pediatric hip disease. The studies are listed in Table 25-1, and, in general, they have had good results.

Table 25–1 Outcomes

Complications

The technique of hip arthroscopy is well described and considered to be safe for most patients. No cases of avascular necrosis after hip arthroscopy have been described to date. The most common complications involve nerve palsy injuries, with the sciatic and pudendal nerves being particularly at risk. Injuries to the lateral femoral cutaneous nerve, the extravasation of fluid into the abdominal cavity, equipment failure, and the inability to complete the procedure have all been reported, and recurrent labral tearing has been described as well. Attention to anatomic landmarks and minimizing traction times can decrease these complications.

Annotated references and suggested readings

Berend K.R., Vail T.P. Hip arthroscopy in the adolescent and pediatric athlete. Clin Sports Med. 2001;20(4):763-778.

This is a review of hip problems in adolescent and pediatric athletes that details the authors’ experiences with hip arthroscopy in 8 patients, with reportedly good results..

Bould M. Arthroscopic diagnosis and treatment of septic arthritis of the hip joint. Arthroscopy. 1993;9(6):707-708.

This is an early report about the use of arthroscope lavage for the treatment of septic arthritis of the hip as an alternative to formal arthrotomy..

Bowen J.R., Kumar V.P., Joyce J.J.III, et al. Osteochondritis dessicans following Perthes disease. Clin Orthop. 1986;209:49-56.

This is a discussion of hip arthroscopy for the removal of osteocartilaginous fragments after Perthes disease. The joint is evaluated for degenerative joint disease as well..

Fischer S.U., Beattie T.F. The limping child: epidemiology, assessment, and outcome. J Bone Joint Surg Br. 1999;81B(6):1029-1034.

This article provides guidelines for the evaluation of the limping child in the emergency department. The epidemiology of limping is included, with the main diagnosis being transient synovitis (39.5%)..

Futami T., Kasahara Y., Suzuki S., et al. Arthroscopy for slipped capital femoral epiphysis. J Pediatr Orthop. 1992;12:592-597.

In this study, hip arthroscopy was used to evaluate the hip after slipped capital femoral epiphysis that demonstrated the erosion of articular cartilage in the anterosuperior region and damage to the posterolateral aspect of the labrum. Findings were consistent with traumatic injury, and no arthroscopic treatment was performed..

Griffin D.R., Villar R.N. Complications in arthroscopy of the hip. J Bone Joint Surg Br. 1999;81B(4):604-606.

This article describes a complication rate of 1.6% among 640 hip arthroscopy patients. These complications included transient palsies of the sciatic and femoral nerves, perineal injuries, bleeding, bursitis, and instrument breakage..

Gross R.H. Arthroscopy in hip disorders in children. Orthop Rev. 1977;6:43-49.

This article describes early experience with hip arthroscopy for patients with congenital dislocation of the hip, Perthes disease, slipped capital femoral epiphysis, and subluxation..

Holgersson S., Brattstrom H., Mogensen B., et al. Arthroscopy of the hip in juvenile chronic arthritis. J Pediatr Orthop. 1981;1(3):273-278.

Hip arthroscopy is described as a useful technique for the diagnosis of the hip among juvenile patients with arthritis because it provides better cartilage detail and useful synovial information..

Ikeda T., Awaya G., Suzuki S., et al. Torn acetabular labrum in young patients. J Bone Joint Surg Br. 1988;70B(1):13-16.

The authors describe diagnostic arthroscopy for a torn labrum in adolescent patients. Tears were located primarily on the posterosuperior portion of the labrum. Repeat arthroscopy several months later did not demonstrate healing of the labrum, and one patient required open labral resection..

Kim S.J., Choi N.H., Ko S.H., et al. Arthroscopic treatment of septic arthritis of the hip. Clin Orthop Relat Res. 2003;407:211-214.

This article details a 4-year follow up of arthroscopic drainage of the septic hip in 10 patients, with good results..

Kocher M.S., Bishop J.A., Weed B., et al. Delay in diagnosis of slipped capital femoral epiphysis. Pediatrics. 2004;133(4):322-325.

In this study, up to 25% of patients with slipped capital femoral epiphysis presented with knee pain, which led to a delay in diagnosis. A delay in diagnosis correlates with the increased severity of the slip angle..

Kocher M.S., Kim Y.J., Millis M.B., et al. Hip arthroscopy in children and adolescents. J Pediatr Orthop. 2005;25(5):680-686.

This is the largest published series of hip arthroscopies in pediatric patients. Labral debridement for isolated tears or as a result of hip dysplasia after periacetabular osteotomy and loose-body excision in patients with Perthes disease resulted in improvement..

Kuklo T.R., Mackenzie W.G., Keeler K.A. Hip arthroscopy in Legg-Calve-Perthes disease. Arthroscopy. 1999;15(1):88-92.

This case report of debridement for an osteochondral lesion after Legg-Calve-Perthes disease demonstrated good results after 5 months..

Mintz D.N., Hooper T., Connell D., Buly R., Padgett D.E., Potter H.G. Magnetic resonance imaging of the hip: detection of labral and chondral abnormalities using noncontrast imaging. Arthroscopy. 2005;21(4):385-393.

With the use of a noncontrast magnetic resonance imaging technique with a small pixel size and a fast-spin-echo sequence, the reliability of the detection of labral tears and cartilage defects was comparable to that of magnetic resonance arthrography and exceeded that of previous noncontrast magnetic resonance imaging techniques..

Schindler A., Lechevallier J.J.C., Rao N.S., et al. Diagnostic and therapeutic arthroscopy of the hip in children and adolescents: evaluation of results. J Pediatr Orthop. 1995;15:317-321.

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