Osteoarthritis (OA) is the main cause of hip pain and disability in people over the age of 50 (6,9). The net result of osteoarthritis is cartilage degradation (14). Conservative medical management of hip osteoarthritis often requires the use of nonsteroidal antiinflamatory drugs (NSAID) that can be a source of severe adverse events, particularly in older patients (12). Because of the weightbearing nature of the hip, in late stages of the disease, total hip arthroplasty is often necessary.
A 2006 Cochrane review of intra-articular viscosupplementation (VS) in knee osteoarthritis concluded that VS is superior to placebo, VS in the knee is safe (compared with NSAID and intra-articular corticosteroids), and VS has more prolonged effects than intra-articular steroids; finally, it overall supported the use of VS for the treatment of knee OA (1). Proposed mechanisms for efficacy of viscosupplementation include the following: restoration of elastic and viscous properties of the synovial fluid, antiinflammatory effects, antinociceptive effects, and normalization of hyaluronan synthesis by synoviocytes (10). The use of intra-articular injections of hyaluronan derivatives for viscosupplementation of the hip joint as a treatment for osteoarthritis appears to be safe and effective in more than 25 yr of use in Europe (17).
EVIDENCE FOR INTRA-ARTICULAR HIP VS
Although in their review of VS for symptomatic hip osteoarthritis, Conrozier and Vignon concluded that, in the absence of placebo-controlled studies, the efficacy of intra-articular injections of hyaluronan or its derivatives cannot be determined conclusively (5), more than 11 studies suggest that VS in the hip is as effective as in the knee (5,11,15,17).
Migliore et al.'s prospective study on the symptomatic effects of intra-articular administration of hylan G-F 20 on osteoarthritis of the hip showed statistically significant improvements in all outcomes measured (Lequesne index, visual analog scale [VAS], and NSAID consumption) at 2 and 6 months follow-up. This series was based on 30 patients receiving from one to three intra-articular ultrasound guided injections of hylan G-F 20. There were no systemic adverse events (11).
In another prospective study of 14 patients with hip osteoarthritis, each patient received three weekly ultrasound guided injections of 2 mL of a hyaluronan derivative. There were no systemic adverse effects. There were statistically significant improvements in all measured outcomes with benefits still present at 90 d: walk time initial, 15 s; at 90 d, 12.28 s; Lequesne score from 12.6 initial to 6.9 at 90 d; significant improvement in VAS with walking and night pain (3).
Tikiz et al. compared low molecular weight (LMW) hyaluronan (Ostenil) and high molecular weight (HMW) hylan G-F 20 (Synvisc) in the treatment of hip osteoarthritis. Fluoroscopic guidance was used to inject 32 hips (25 patients) with LMW hyaluronan and 24 hips (18 patients) with HMW hyaluronan. VAS, Lequesne index, and Western Ontario and McMaster Osteoarthritis Index (WOMAC) were measured at baseline, 1, 3, and 6 months. Again, there were no systemic adverse effects. Both LMW and HMW hyaluronan preparations tested produced statistically significant improvement in all outcomes out to 6 months: 40% reduction in VAS, 48% reduction in Lequesne index, and 40% improvement in WOMAC scores. No significant difference was found between higher- and lower-weight hyaluronan groups (16).
A prospective study by Gaston et al. of fluoroscopically-guided intra-articular hip VS with synthetic hyaluronic acid for osteoarthritis measured efficacy, safety, and comparison with preinjection radiographs. Fifteen hips were injected weekly for 3 wk with Suplasyn hyaluronan. Harris Hip Score and weightbearing anterior posterior (AP) pelvis films were done at baseline and 3 and 6 months. The results showed a statistically significant improvement in Harris Hip Score at 3 months, which continued out to 6 months. Analysis of radiographic data (using Kelgren and Lawrence grades, as well as minimum joint space width) showed that those with fewer initial radiographic changes had a trend towards an increased benefit from hip viscosupplementation. Again there were no systemic adverse effects (7).
Van den Bekerom et al.'s literature review and prospective study of 60 patients examined the use of VS in symptomatic severe hip osteoarthritis as a method to reasonably delay hip replacement. One of three forms of hyaluronan was randomly assigned, Orthovisc, Synvisc, or Fermatron. Each patient received a maximum of three fluoroscopy guided injections every 2 wk. The results at the 6-wk follow-up showed statistically significant decrease in VAS (66.3 initial to 49.3), and a 59% decrease in the need for daily NSAID. They quoted the first study published on VS in the hip, Bragatini et al. describing hip VS in 1984 with 50 hips receiving three weekly injections, which showed statistically significant improvement in VAS and joint mobility. In their review of 10 studies published, they concluded that this technique is reasonably well-tolerated and safe, with no systemic adverse effects and minor local adverse events in 8.3% of patients. Finally, they concluded that VS in the hip delayed surgical intervention by at least 6 months (17).
Conrozier et al.'s 2008 prospective study of 34 patients, a single fluoroscopy guided hip injection of 3 mL of a hyaluronic-acid preparation (non-animal-stabilized-hyaluronic-acid) showed statistically significant improvements in the Lequesne index and WOMAC scores. Before injecting, the hip was aspirated if an effusion was present. There were no severe adverse events related to the treatment or to the procedure. They did have 15 of 28 assessable patients experience a transient increase of pain in the injected hip, which resolved spontaneously within 1 wk (4).
In over 11 published studies on VS of the hip using imaging to guide the injection, there were no systemic adverse effects. Self limited local adverse events occurred in 5%-8% of patients and included mild transient sensation of heaviness in the hip and mild short-term increase in pain in the hip. The most common adverse effect listed was mild self-resolving soreness at the injection site (17).
ULTRASOUND GUIDED INJECTION TECHNIQUE FOR ANTERIOR APPROACH
Sofka et al. in their series of 358 hip injections and aspirations believed that real-time ultrasound guidance should be the primary method used for accessing the hip joint. They had no cases of inadvertent vascular or femoral nerve puncture or other significant adverse events. The needle path trajectory is on average 20-30 mm from the femoral neurovascular structures with the anterior longitudinal approach (13). Before injecting any joint, the person performing the procedure must have a clear understanding of the anatomy.
The technique for performing hip joint injections under real-time ultrasound guidance is as follows: with the patient supine, widely prepare the overlying skin with chlorohexidine/alcohol or betadine per manufacturer's recommendation. Drape the patient as needed to keep the injection site sterile. Clean the probe with appropriate bacteriocidal antisepsis. The use of sterile technique including sterile gloves, sterile probe covers, and sterile ultrasound gel is highly recommended for hip joint injections. Using the nondominant hand to hold the probe, position a 2-5 MHz (low frequency) curved probe long axis along the anterior femoral neck/femoral head and obtain a good view of the redundant portion of the anterior hip capsule (anterior recess) at the junction of the femoral neck and femoral head (Fig. 1). This view will facilitate a long-axis injection. Identify the overlying neurovascular bundle containing the ascending branch of the lateral femoral circumflex artery. The use of color or power Doppler may facilitate this (Fig. 2).
Using the dominant hand to hold the syringe, inject approximately 3-5 cc of buffered 2% lidocaine as a skin weal and along the proposed needle track (Fig. 3). Clear air from the needle before entering the skin to avoid having the subsequently injected air obscure the ultrasound view. Using a 20- to 22-gauge needle at least 100-mm long (longer in larger patients), advance the needle into the anterior recess of the anterior hip capsule. If an effusion is present, aspirate the effusion before injecting the viscosupplement (Figs. 4 and 5). Change from the aspirating syringe to the VS syringe with the needle remaining in place. An assistant with sterile gloves and hemostat holding the hub of the needle will facilitate this. Slowly inject the viscosupplement and observe the hip capsule expanding. If doing a diagnostic injection to confirm the hip joint as the pain generator, consider injecting 8-10 cc of 1% lidocaine. The use of either bupivicaine or 2% lidocaine is not recommended because of their increased toxicity to chondrocytes (8). Strongly consider capturing an image to document the placement of the needle in the hip joint.
Injection of the hip joint with ultrasound guidance is relatively straightforward, with excellent anatomical landmarks and a large target area with relatively few structures to avoid. If the real-time ultrasound guided injectionist is inexperienced, he or she will find that deeper injections require more skill. Obtaining a good image of the needle as it advances is more challenging and demands better technique to increase sound wave reflection from the needle back to the probe.
FACTORS INFLUENCING EFFECTIVENESS
VS appears to be effective for pain management in knee OA (14). The hip is a very different joint from the knee. It is reasonable to state that the nature of the weightbearing surfaces and hyaline cartilage interfaces in the hip are at least somewhat different from those of the knee. This author postulates that hip joint communication with the iliopsoas bursa may be a factor in studies of the effectiveness of VS in the hip, because of the fact that the viscosupplement may not remain in the hip joint in significant concentration to have a more pronounced effect. Wunderbaldinger et al. demonstrated that 18 of 18 patients with iliopsoas bursitis had surgically confirmed communication between the bursa and the hip joint (18) (Fig. 6). Berejiklian et al. demonstrated a 15% rate of communication between the bursa and the joint in healthy adults (2). This author suspects that the true rate of communication between the hip joint and iliopsoas bursa is between 15% and 100%. These two studies suggest that rates of communication between the hip joint and iliopsoas bursa increase in the presence of hip pathology.
VS of the hip for osteoarthritis appears to be safe and effective in more than 25 yr of use in Europe. Although no double-blind placebo controlled studies were found in a search of the medical literature, more than 11 studies suggest that VS in the hip is as effective as VS in the knee. It appears to be a safe and reasonable alternative to NSAID or intra-articular steroids for the treatment osteoarthritis pain. VS in the hip may delay the need for hip replacement surgery. VS in the hip appears to work better in patients with fewer radiographic changes of OA, although a trial of VS may be a reasonable course of action in severe OA in a nonsurgical patient. Placement of viscosupplement in the hip under real-time ultrasound or fluoroscopic guidance is safe and well-tolerated. At least two studies suggest that there may not be clinically significant differences in different weights/types of hyaluronan.
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Copyright © 2009 by the American College of Sports Medicine.
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