Hip Arthroscopy

By Dominic Carreira, MD; Charles A. Bush-Joseph, MD
ORTHOPEDICS 2006; 29:517

As our understanding of arthroscopic anatomy, indications, potential complications, and techniques has evolved, hip arthroscopy has become a successful treatment method for a variety of hip pathologies in properly selected patients. Patients with symptomatic intra-articular hip joint pathology and minimal arthritic changes benefit the most from arthroscopic intervention. Results vary based on the indication, with removal of loose bodies and labral tears proving to be the most efficacious.1 Complications include articular scuffing, instrument breakage, and neurovascular and cutaneous nerve injuries.2-4

Similar to arthroscopic knee and shoulder surgery, hip arthroscopy is gaining greater use as developments in techniques allow for minimally invasive diagnostic and therapeutic interventions. Hip arthroscopy has a recent history, having been used minimally until the late 1980s. Current indications include removal of loose bodies, synovial biopsy, subtotal synovectomy, management of labral tears, synovial chondromatosis, osteochondritis dissecans, chondral lesions, and the treatment of septic arthritis.5 Patients with chronic and unresolved intra-articular hip joint pain also benefit from arthroscopic evaluation.

Diagnosis

Hip pain often is mechanical in quality and may arise from extra- or intra-articular sources. The majority of patients with hip pain respond well to conservative therapy (rest, nonsteroidal anti-inflammatory drugs, and physical therapy) and the hip pain goes away over time. However, in those patients with persistent symptoms, a carefully elicited history and physical examination may be suggestive of various anatomical and pathological processes. Determining the signs and symptoms suggestive of intra-articular pathology are essential in differentiating patients who may benefit from hip arthroscopy. The extra-articular causes of hip pain, including sacroiliac joint pathology, stress fractures, trochanteric bursitis, occult hernias, and tendon injuries (iliopsoas, piriformis, rectus, hamstring, or adductor), occur more frequently than the intra-articular causes of hip pain.6 In the senior author’s (C.A.B.-J.) sports medicine practice, <20% of patients presenting with hip pain have intra-articular pathology.

Several signs and symptoms may be suggestive of intra-articular hip pathology. The presence of groin pain and/or anterior thigh pain extending to the knee is a significant indicator, especially if activity-related. Lateral thigh pain typically is due to trochanteric bursitis and posterior buttock and sacroiliac pain usually is due to spinal or sacroiliac conditions. Likewise, mechanical symptoms, ie, popping, locking, or restricted range of motion (ROM), also are suggestive of an intra-articular process. All age groups may be affected, and a history of a preceding traumatic event such as a fall or twist often is reported. Pain typically is exacerbated with activity and improved with rest. In degenerative hip disease, increased pain with activity also is noted, whereas in rheumatoid arthritis, pain and stiffness frequently improve with activity.

Physical Examination

The physical examination is useful to differentiate extra-articular sources of pain. Complete assessment begins with observation of gait. A trendelenburg gait may outline a problem with pelvic stabilization secondary to abductor weakness. Thigh muscle atrophy is suggestive of a chronic disuse problem, which may have resulted from pain or a mechanical limitation. Leg-length discrepancy can be a cause of low-back and posterior buttock pain. Range of motion, both actively and passively, should be measured. The active straight leg raise may provoke local joint-related symptoms while the passive straight leg raise test is more typical of lumbar nerve root irritation. Patients with labral pathology may report pain when the hip is internally rotated while flexed to 90°

Limitation of internal rotation in an adult is consistent with osteoarthritis, and in the pediatric population is consistent with slipped capital femoral epiphysis. Palpation of the joint is important in localizing pain. Anterior groin tenderness is suggestive of hip joint pain but also may be present with rectus femoris or iliopsoas muscle injuries. Coxa Saltans (snapping hip syndrome) is noted in patients who can produce an audible snap with active hip motion (flexion external rotation) but have no findings with passive motion. The audible snap is due to the rectus femoris or iliopsoas tendon snapping across the hip capsule. Posterolateral tenderness is suggestive of trochanteric bursitis. Crepitus with passive hip motion is indicative of osteoarthritis. The Faber test (passive flexion, abduction, external rotation) stresses the sacroiliac joint but also has been described for isolating symptoms to the hip. The most specific test for intra-articular hip pain is log rolling. This moves only the femoral head in relation to the acetabulum and does not stress the myotendinous structures or nerves.

Imaging

An anteroposterior (AP) radiograph of the pelvis, and an AP and frog-leg lateral of the hip typically are obtained in the workup of hip pain, especially if the history is suggestive of bony pathology (Figure 1). However, radiologic studies may be non-diagnostic of hip pain in 75% of patients.5 Computed tomography (CT) plays a role if there is suspicion of bony fragments, as in Perthes’ disease or after a traumatic injury (Figure 2). Magnetic resonance imaging (MRI) provides enhanced visualization of soft-tissue anatomy and is useful in assessing bone for osteonecrosis. However, many causes of hip pain (such as labral tears) are not well visualized with MRI.6 Gadolinium enhanced MRI demonstrated a sensitivity of 55% for all intra-articular pathology and 74% for labral tears in patients where other modalities had failed to reveal a source of pain (Figure 3).8

The single most useful diagnostic test of intra-articular pathology is a fluoroscopically guided injection of the hip.9 Intra-articular hip injections using local anesthetic will localize a confusing clinical presentation and is helpful in patients when diagnostic imaging is not helpful.

Despite exhaustive investigation, a subset of patients remain with persistent symptoms, positive physical examination findings, and inconclusive imaging studies. These patients also may benefit from hip arthroscopy.10,11

Current Indications and Contraindications

Indications for hip arthroscopy continue to evolve (Table 1). Nevertheless, proper patient selection remains the key to obtaining successful outcomes. Symptomatic loose bodies are the clearest indication for hip arthroscopy for three reasons: 1) the diagnosis of loose bodies usually is easy to determine 2) Retained intra-articular fragments have a well-established association with a poor prognosis 3) Compared with arthrotomy, arthroscopy is less invasive and less morbid. Disease processes such as synovial chondromatosis, osteochondritis dissecans, degenerative arthritis, and hip dislocation are associated with loose bodies and represent processes in which arthroscopic intervention have resulted in successful outcomes.15

Symptomatic labral lesions are a well-recognized indication, although diagnosis of such lesions often is difficult.13 The acetabular labrum plays an important role in the distribution of forces across the joint surface. Acute labral tears may be a source of persistent pain following closed treatment of a hip dislocation. In addition to dislocations, labral lesions also have been associated with less traumatic injuries, such as twisting or squatting, and in acetabular dysplasia. Because the diagnosis of labral tears often is elusive despite the use of diagnostic measures such as MRI or double-contrast arthrography with CT, labral tears often are a diagnosis of exclusion.

Although many patients suffer from degenerative arthritis of the hip, few are good candidates for arthroscopic treatment (Table 2). Guidelines for patient selection include: 1) age: younger patients are more likely to benefit; arthroscopy serves as a temporizing measure to delay total arthroplasty; 2) radiographic findings: the less advanced the degenerative disease, the more likely the benefit; and 3) recent onset of symptoms.12

Surgical Technique

Two elements of preoperative planning are important in planning for hip arthroscopy. First, the hip ROM must be evaluated to determine the presence of contractures. If there is a contracture, the hip must be left in that position to allow for adequate distraction and visualization. Second, radiographs should be completed to identify spurs or dysplasia. Large spurs may block entrance into the joint, and hips with dysplasia have been shown to have poorer outcomes.

Two commonly used patient positions for performing hip arthroscopy are supine and lateral decubitus.16,17 Arguments for using the supine position include the readily available standard fracture table and traction equipment and the user-friendly layout of the operating room. Arguments in favor of the lateral decubitus position include enhanced instrument maneuverability, particularly in obese patients, as fatty tissue tends to fall out of the way. Also, entrance into the hip joint may be easier using the lateral approach. Portal placement and surgical technique is similar in both positions. Epidural anesthesia is an appropriate alternative to general anesthesia, if an adequate block providing muscle relaxation is attained.

Supine Position

Using a fracture table, the involved hip is placed in abduction at 25° and in slight extension. Flexion is avoided to avoid drawing the sciatic nerve closer to the joint. Neutral rotation is essential during portal placement, but during arthroscopy freedom of rotation allows for increased visualization. The contralateral hip also is abducted to facilitate access of the c-arm and is placed under slight traction to stabilize the patient (Figure 4). The well-padded perineal post then is positioned against the pubic ramus and ischial tuberosity, providing lateralization of the proximal medial thigh. Ideally the traction vector runs parallel to the femoral neck, making the distracting force most efficient. Due to the nature of the hip joint, ie, the tough connective tissue capsule and the stability of the ball and socket joint itself, a distractive force must be applied to the extremity to allow proper visualization during arthroscopy. Using a tensiometer, a traction force of 25-50 lbs is applied, with a goal of 8-10 mm distraction. A vacuum is created within the joint, and later is ablated with instillation of joint fluid or air, thereby decreasing the required traction force (Figure 5). The joint capsule becomes more lax after a few minutes of traction, also resulting in a need for less force to maintain an adequate joint space. Once adequate distraction of the joint has been achieved, the traction is released during prepping and draping to reduce total traction time, which should be limited to <2 hours.

Landmarks for placement of the portals include the superior margin of the greater trochanter and the anterior superior iliac spine (Figure 6). The entrance site for the anterolateral portal is the most anterior aspect of the superior margin of the greater trochanter. The posterolateral portal site is at the most posterior aspect of the same margin.

Three standard portals are used for hip arthroscopy: anterior, anterolateral, and posterolateral. The anterolateral portal site is placed first because it is the safest from the femoral and sciatic neurovascular structures. This portal penetrates the gluteus medius prior to entering the lateral aspect of the capsule at its anterior margin and provides the best visualization of the anterior wall and labrum. An 18-gauge 6-inch spinal needle is introduced at the above-mentioned landmark, and is directed into the joint space under fluoroscopic guidance. Special attention must be taken to avoid penetration of the acetabular labrum (Figure 7). As the needle penetrates through the capsule, there is a palpable decrease in resistance. If the needle is directed into the labrum, the resistance is greater. The joint then is distended with approximately 40 cc of fluid and the intracapsular position of the needle confirmed by backflow of fluid. A superficial skin nick is made, a switching wire is fed through the spinal needle into the joint space, and the spinal needle is removed. A 5.0-mm arthroscopic cannula with obturator is passed over the wire into the joint space. Fluoroscopic assistance may prevent scuffing of the articular surface of the femoral head with the obturator. The switching wire then is removed, and a 30° scope typically is used first to inspect the joint, followed by a 70° scope for further visualization as well as placement of the remaining portals.

The anterior portal is placed second using both fluoroscopic guidance and arthroscopic visualization to insure proper entrance thru the joint capsule. This portal penetrates the muscle belly of the sartorius and the rectus femoris before entering the anterior capsule and provides the best visualization of lateral labrum. At the portal level, the lateral femoral cutaneous nerve usually has divided into three or more branches (Figure 8). The skin landmark is determined as the bisector of two lines: one drawn distally from the anterosuperior iliac spine and the other drawn transversely from the superior margin of the greater trochanter. The spinal needle is introduced at this landmark and oriented toward the joint space, aiming approximately 45° posteriorly and 30° medially. Once the joint has been entered, a superficial skin nick is made to avoid damage to the lateral femoral cutaneous nerve branches. The switching wire then is used, allowing removal of the spinal needle and allowing passage of the cannula with obturator over the wire. Some authors recommend blunt dissection down to the fascia before introducing the obturator to move the nerve branches away from the entry site.

The posterolateral portal insertion site is placed last. This portal penetrates both the gluteus medius and the gluteus minimus prior to entering the lateral capsule at its posterior margin and provides the best visualization of posterior wall and labrum. The spinal needle is oriented horizontally and medially. The sciatic nerve should be well posterior and the superior gluteal nerve well superior to this insertion site. Once the three standard portals are established, the joint can be visualized from several perspectives to assess the pathology. The joint can be viewed with or without fluid distension.

Most hip arthroscopy procedures require the use of multiple portals for the proper positioning of hand instruments, power shavers, and electrocautery devices. Once the portals are established, the surgeon is able to accomplish a variety of intra-articular procedures.

Lateral Position

A fracture table or traction apparatus is set for the lateral decubitus position, with the involved leg placed upward.14 Support of the lower torso decreases the vertical forces on the post. The hip should be placed in slight flexion, abduction, and external rotation to relax the capsule.

For the traction apparatus, a conventional operating room table is used. The apparatus includes a foot piece and stretcher to hold the leg, a well-padded perineal post for countertraction, and a tensiometer to gauge the amount of traction applied. The perineal post is pushed upward against the medial portion of the thigh on the involved leg, keeping the post away from the branch of the pudendal nerve that crosses over the pubic ramus. The surgeon stands in front of the patient and the monitors and equipment are placed in back of the patient. The portal entry sites and landmarks are the same as for the supine position.

For both approaches, releasing the capsule around the portal sites with an arthroscopic knife passed through the cannula improves maneuverability within the joint. Typically, the anterolateral portal is used for the arthroscope, the posterolateral portal for operating instruments, and the anterior portal for outflow.

Extra-length curved shaver blades have been designed for operative arthroscopy around the convex surface of the femoral head. Extra-length flexible cannulas allow for passage of these curved blades.

Postoperative management

Hip arthroscopy typically is performed on an outpatient basis. Depending on the indication for surgery, weight bearing and assisted ambulation with crutches generally is allowed immediately postoperatively. Rehabilitation is individualized to the type of pathology and the procedure performed. The short-term use of crutches is helpful until a function active ROM is achieved with simple debridement. If a microfracture technique is used, the patient remains on crutches touch down weight bearing for six weeks. Passive motion with a stationary bicycle is started immediately postoperatively and joint mobilization exercises are used to prevent contractures.

Results

Baber et al15 reported outcomes of a series of 328 patients. Seventy-four percent of patients who underwent arthroscopy benefited, by improvement of symptoms (21%) or by a change in diagnosis (53%). In 19% of patients no pathology was found at the time of arthroscopy. Farjo et al13 reviewed a series of 280 patients, 29 of which underwent labral repairs. Sixty-four percent of these patients had mechanical symptoms (such as clicking or popping sensation in the hip) on presentation. No physical examination technique was found to correlate with the presence of tear. Of those patients with radiologic evidence of arthritis prior to arthroscopy, only 21% were felt to obtain good to excellent results from the procedure, compared to 71% of patients without evidence of arthritis. Thus, arthritis may correlate with poorer outcomes after arthroscopic treatment of labral tear.

Complications

Although hip arthroscopy historically is considered a technically challenging procedure, the reported complication rates are <2% (Table 3).18,19 In a review of 1491 published cases, the Arthroscopy Association of North America reported a 1.34% complication rate, with six transient or permanent pudendal nerve injuries, four transient sciatic nerve palsies, three partial or total lateral femoral cutaneous nerve injuries, one heterotopic ossification, and one abdominal fluid extravasation. Iatrogenic injury to the articular surfaces and labrum are avoided with proper instrumentation and careful technique.

Care must be taken when applying the distractive force. An adequate balance between too much distraction (increased risk of neurovascular compromise) and too little distraction (struggle for access and instrumentation) requires fine-tuning.20

Summary

With adequate patient screening and attention to complications specific to the hip joint, hip arthroscopy can be performed safely and effectively. When used in appropriately selected patients, the reduced recovery and rehabilitation time is significant. In the past decade, the indications for hip arthroscopy have evolved to include a variety of pathologies, which has lead to a dramatic rise in its use.

Pearls and Pitfalls (tips of the trade)
  • Patient selection. Patients with mechanical symptoms have the best results.
  • Setup (positioning)
    Supine. On a fracture table, ensure appropriate abduction, lateralization, traction and countertraction.
    Lateral. Familiar “hip arthroplasty” position.
  • Assessment of the distractibility of the joint. At least 8 mm.
  • Placement of portals: (in order)
    1. Anterolateral. Safest, placed first. Avoid cannulating through the labrum or scuffing the femoral head.
    2. Anterior. Superficial skin nick precludes damage to branches of the lateral femoral cutaneous nerve.
    3. Posterolateral. Avoid the sciatic nerve by maintaining the extremity in neutral rotation and by directing spinal needle horizontally. Minimize total traction time to <2 hours.

References

  1. Byrd JW, Jones KS. Prospective analysis of hip arthroscopy with 2-year follow-up. Arthroscopy. 2000; 16: 578-587.
  2. Sampson TG. Complications of hip arthroscopy. Clin Sports Med. 2001; 20: 831-835.
  3. Funke EL, Munzinger U. Complications in hip arthroscopy. Arthroscopy. 1996; 12:156-159.
  4. Byrd JW. Operative Hip Arthroscopy. New York, NY: Thieme Medical Publishers Inc; 1998.
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  10. Frich LH, Lauritzen J, Juhl M. Arthroscopy in diagnosis and treatment of hip disorders. Orthopedics. 1989; 12:389-392.
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  13. Farjo LA, Glick JM, Sampson TG. Hip arthroscopy for acetabular labral tears. Arthroscopy. 1999; 15:132-137.
  14. Glick JM, Sampson TG, Gordon RB, Behr JT, Schmidt E. Hip arthroscopy by the lateral approach. Arthroscopy. 1987; 3:4-12.
  15. Baber YF, Robinson AH, Villar RN. Is diagnostic arthroscopy of the hip worthwhile? A prospective review of 328 adults investigated for hip pain. J Bone Joint Surg Br. 1999; 81:600-603.
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  17. Byrd JW. Hip arthroscopy. The supine position. Clin Sports Med. 2001; 20:703-731.
  18. Griffin KM. Rehabilitation of the hip. Clin Sports Med. 2001; 20:837-850.
  19. Griffin DR, Villar RN. Complications of arthroscopy of the hip. J Bone Joint Surg Br. 1999; 81: 604-606.
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Authors

Drs Carreira and Bush-Joseph are from the Department of Orthopedic Surgery, Rush Presbyterian-St Luke’s Medical Center, Chicago, Ill.

Drs. Carreira and Bush-Joseph have no industry relationship to declare.

The material presented at or 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 faculty endorse or recommend any techniques, commercial products, or manufacturers. The faculty/authors may discuss the use of materials and/or products that have not yet been approved by the U. S. Food and Drug Administration. All readers and continuing education participants should verify all information before treating patients or utilizing any product.

Reprint requests: Charles A. Bush-Joseph, MD, 1725 W Harrison, Ste 1063, Chicago, IL 60612.