Fig. 14.1
Right hip DJD with joint space narrowing and subchondral sclerosis
14.2 Epidemiology
Degenerative joint disease (DJD) is the most common cause of musculoskeletal pain and disability. A progressive and debilitating disease, DJD affects over 15 % of the world’s population [1] and is a major cause of morbidity and health care expenditures. One longitudinal population-based study evaluating over 3000 subjects has estimated the lifetime risk of hip DJD as 25 % [2]. Likewise, data from the Center for Disease Control and Prevention’s Behavioral Risk Factor Surveillance System shows that risk to increase to 35 % for those over the age of 50 and further to more than 55 % for those over the age of 70 [3]. One study ranked hip and knee DJD as the 11th highest contributor to global disability of 291 conditions studied [4]. As the population continues to age and prevalence of obesity continues to rise, the cost and consequences from DJD will continue to grow.
DJD, characterized by joint pain and dysfunction, is associated with defective integrity of the articular cartilage and related changes in the underlying bone and joint margins. Currently, there is no known cure for DJD. New treatments and disease-modifying therapies are currently under investigation, but the etiology of DJD is still not completely understood. Therapy is aimed at decreasing pain and dysfunction and increasing mobility and overall quality of life. The hip is the second most common large joint to be affected by DJD [5, 6]. The prevalence of hip DJD ranges from 3 % to 11 % in Western populations aged over 35 years [6], with reported prevalence variation due to differences in radiographic case definitions [7].
14.3 Risk Factors
Risk factors associated with DJD include systemic factors, such as genetics and bone density, as well as biomechanical factors that affect the joints, such as reduced muscle strength [8]. Age, obesity, high bone mass, joint location, joint malalignment, trauma, gender, comorbidities, biochemical changes, and lifestyle (participation in weight-bearing sports and occupations that require prolonged standing, lifting or moving of heavy objects) have all been associated with the development of DJD [1, 9, 10]. Age-related changes in cartilage alter the biomechanical characteristics of collagen and proteoglycans. Mechanical wear, chondrocytes, and cytokines, principally interleukin (IL)-1β (beta) and transforming growth factor (TGF)-β (beta), all play roles in the pathogenesis of the disease [11].
In males, trauma and age are associated with DJD. A positive association with hip trauma is also found in unilateral but not bilateral hip DJD. Obesity is associated with bilateral but not unilateral hip DJD [12]. Several studies have found an association between increasing BMI and an increased incidence of DJD [10, 13, 14].
Other secondary risk factors associated with DJD include hemochromatosis, hyperparathyroidism, hypothyroidism, acromegaly, hyperlaxity syndromes, Paget’s disease, gout, and chondrocalcinosis [9].
14.4 Diagnosis
The accurate diagnosis of hip DJD relies on a combination of both clinical and radiographic findings. Radiographic evidence of joint degeneration and characteristic subjective symptoms of pain and disability have been found to be superior to clinical criteria alone.
Physical symptoms include generalized hip pain, pain in the lateral or anterior thigh and groin, and pain with prolonged ambulation. Physical signs include antalgic gait, decreased range of motion, and pain with internal rotation. The pain is often described as deep and achy. In early disease, the pain may be intermittent and mostly with joint use, but as the pain becomes more chronic, patients may also experience pain at night. The joint is often described as “stiff” and patients have difficulty with initiating movements. In advanced disease, crepitus may develop and range of motion may become limited [15]. Radiographic findings in patients with DJD include cartilage space narrowing, osteophytosis, subchondral cysts, subchondral sclerosis, femoral neck buttressing, and femoral head remodeling (Figs. 14.2, 14.3, 14.4, and 14.5) [11, 16]. Historically, radiographic evidence of osteophytes, cysts, and subchondral sclerosis has been used to diagnose DJD; however, more recently research has focused on joint space width (JSW) as the primary determinant and radiographic criterion for hip DJD.
Fig. 14.2
Hip DJD with joint space narrowing
Fig. 14.3
Hip DJD with osteophytes and subchondral sclerosis
Fig. 14.4
Severe hip DJD with loss of joint space and subchondral sclerosis
Fig. 14.5
Severe hip DJD with subchondral cysts, osteophytes, subchondral sclerosis, and joint space loss
Jacobsen et al. found that minimum JSW less than or equal to 2 mm had the closest association with self-reported hip pain in 3807 subjects whose mean age was 61 years old [7]. Gupta et al. found that cartilage space narrowing was the most sensitive predictor of hip DJD [11]. Croft et al. studied 1315 men aged 60–75 and found minimal joint space to be the best radiographic criterion of hip DJD to use in epidemiologic studies, at least for men [17]. In 1991, Altman et al. proposed a classification tree of (1) hip pain and osteophytosis or (2) hip pain and cartilage space narrowing with a sedimentation rate less than 20 mm/h. The study demonstrated a sensitivity of 89 % and a specificity of 91 % for hip DJD [18].
Once the diagnosis is made, severity can be quantitatively tracked using the Western Onterio and McMaster Universities DJD Index (WOMAC) scores , which is composed of 24 items assessing pain, stiffness, and physical function. The Visual Analog Scale (VAS) for pain is an alternative, more general measure of disease-associated pain. However, many providers choose to track disease severity by historical symptoms alone.
14.5 Nonoperative Management
Overall, the goals of nonoperative management in DJD are to reduce pain and functional impairment, to improve mobility, and perhaps to delay or prevent the need for surgery. Treatments should be chosen to limit the side effects of therapy. Expert opinion supports the statement that optimal management of hip DJD requires a combination of nonpharmacologic and pharmacologic treatment modalities (Table 14.1) [6].
Table 14.1
Nonoperative management of hip DJD
Nonpharmacologic | Pharmacologic |
|---|---|
Exercise | Intra-articular corticosteroid |
Weight loss | Intra-articular viscosupplementationa |
Patient education and self-management programs | Acetaminophen |
Assistive devices | NSAIDs |
Acupuncture | Tramadol |
Opioids | |
Glucosamine and chondroitin | |
Diacerein | |
Other supplements |
While several well-recognized organizations have produced evidence-based nonoperative treatment guidelines for DJD, three have created specific recommendations for hip and knee DJD: the American College of Rheumatology (ACR) , the DJD Research Society International (OARSI) , and the European League Against Rheumatism (EULAR) [19–21]. All three include review of high-level evidence including meta-analyses, systematic reviews, and randomized controlled trials.
Treatment of hip DJD should be tailored to the individual patient taking into account patient comorbidities, current medications, level of pain, disability and handicap, degree of structural damage, and baseline physical activity and functional status.
14.5.1 Nonpharmacologic Therapy
Nonpharmacologic treatment of hip DJD should include patient education, self-management programs, aerobic and resistance exercise, lifestyle changes, weight reduction if obese or overweight, and acupuncture. The evidence weakly supports the use of assistive devices such as walking canes and wheeled walkers to reduce pain and increase exercise participation [21]. Treatments previously in use that evidence suggests are ineffective include electromagnetic therapy [19].
14.5.1.1 Exercise: General Benefit
Exercise and physical activity have clearly been shown to benefit those with large-joint DJD [5, 15]. Decreased lower extremity strength is associated with increased disability in people with DJD. Disease-related factors such as impaired muscle function and reduced fitness are amenable to therapeutic exercise. Expert opinion from a 2005 systematic review states that improvement in muscle strength and proprioception gained from exercise programs may reduce the progression of hip DJD. Notably, the effectiveness of exercise is thought to be independent of the presence or severity of radiographic findings [5].
Svege et al. found that an exercise program specifically designed for hip DJD consisting of strengthening, flexibility, and functional exercises significantly delayed the time until total hip arthroplasty (THR) [22]. Interestingly, in this study the exercise therapy group had better self-reported hip function, but no significant differences were found for pain or stiffness.
Perhaps unsurprisingly, there is evidence to show that the beneficial post-treatment effects of exercise are not sustained in the long-term after routine exercise is no longer maintained [23].
14.5.1.2 Exercise: Type
Land-based exercise programs and water-based exercise programs, with components of strength training, aerobic exercise, and flexibility training have been shown to reduce pain and improve function and health status in patients with hip DJD [24, 25]. Likewise, a 2014 Cochrane Review of 10 RCTs concluded that land-based physical exercise programs were effective in reducing pain and improving physical function associated with DJD of the hip [26].
If the resources and facilities are available, water-based therapy (hydrotherapy, aquatic physical therapy) can be an ideal setting for people with DJD. The buoyancy of the water reduces the load across the joints affected by pain and allows for performance of functional closed-chain exercises that would otherwise be too difficult. The warmth and pressure of the water may aid in pain relief, swelling reduction, and ease of movement. Warm water encourages muscle relaxation and reduces guarding around the joints, which leads to increased range of motion and ultimate functional gains [27].
In a 2007 RCT of 71 patients comparing 6 weeks of hydrotherapy versus no treatment, the hydrotherapy group had significantly less pain and improved physical function , strength, and quality of life compared to controls, with benefit sustained 6 weeks after cessation of the program [28]. Foley et al. studied 105 patients randomized to three water- or land-based exercise sessions a week for 6 weeks. Both water and gym exercises were found to improve function, with land-based exercises being better for strength and water-based superior for aerobic conditioning [29]. Similarly, a 2007 Cochrane Review reported some positive short-term effects, but a lack of evidence supporting a long-term effect, leading the authors to suggest that water-based therapy be used as a gateway to land-based exercise therapy [27].
14.5.1.3 Exercise: Adherence and Risk
One of the leading indicators of success and benefit from exercise therapy is patient adherence to the program. The bottom line is that performing exercise is more important than the type performed. Strategies to improve adherence such as long-term monitoring and review, setting specific exercise-related goals that are easy to achieve, frequent encouragement, and inclusion of a spouse or other family member in the exercise should be considered in the exercise prescription.
Supervised classes appear to be as beneficial as treatments on a one-to-one basis [15]. Group exercise and home exercise were found to be equally effective while a supervised group format potentially provides a more cost-effective alternative . Also, social contact with peers may help to increase adherence [5, 15].
Furthermore, while there is no data regarding intensity of exercise in hip DJD, a Cochrane review examining the effectiveness of therapeutic exercise at different intensities in people with DJD of the knee found both high-intensity and low-intensity aerobic exercise to be equally effective in improving patient’s functional status, gait, pain, and aerobic capacity [30]. Studies have also shown that dropout rates are related to the intensity of the exercise, with higher intensity having a higher rate of withdrawal [30]. It is important to carefully tailor the exercise type and intensity to the individual patient, erring on the side of a low-intensity exercise program with a slow progression to achieve maximum short and long-term effects.
There are few contraindications to the prescription of strengthening or aerobic exercise in patients with hip DJD, however, age, comorbidities , resources, and overall mobility should all be taken into account to ultimately increase patient adherence and overall success [5]. Exercise prescription for DJD should include aerobic, strength, and flexibility training. These programs should be individualized.
14.5.1.4 Weight Loss
Obesity is a modifiable risk factor for developing hip DJD and weight loss has been shown to reduce the pain and disability associated with hip DJD [10, 31]. Expert guidelines universally consider weight loss a cornerstone of management for overweight patients with hip DJD [3].
Obesity is thought to contribute to DJD via two general mechanisms. The historically accepted mechanism attributes increased DJD risk to the increased load across weight-bearing joints. However, more recently, a second mechanism has been theorized in which increased levels of adipose-associated systemic inflammatory mediators (i.e., adipokines, free fatty acids, and reactive oxygen species) play a role [32–34]. This biochemical mechanism is based on the observation that the risk of DJD of non-weight-bearing joints is also increased in obese patients compared to non-obese counterparts. Subsequently, some now consider metabolic DJD a subtype of DJD and believe that DJD should be considered a fifth component of metabolic syndrome [35, 36].
Lastly, it is worth noting that some studies have demonstrated increased intra- and post-operative adverse events in THR for obese patients [37–39]. These findings should motivate providers to recommend weight loss as an important treatment modality in the management of hip DJD regardless of the possible progression to THR.
14.5.1.5 Patient Education and Self-Management Programs
The evidence surrounding arthritis self help groups that teach patients how to manage their disease is mixed. A 2014 Cochrane Review of 29 studies by Kroon et al. concluded that review of the generally low quality evidence available regarding self help groups for DJD reveals either no or small benefit to pain, function, and quality of life, but they also concede that self-management education programs are unlikely to cause harm [40]. For those interested in pursuing self help groups , community organizations as well as the Arthritis Foundation can serve as a resource for education materials. Physicians may also organize group visits designed to address DJD alone or in combination with other common comorbidities such as obesity, diabetes, and hypertension.
Self-management programs have been shown to reduce anxiety and improve participants’ perceived self-efficacy to manage their symptoms of DJD. Education that the disease is not relentlessly progressive and self-management tools, such as techniques to deal with problems such as pain, fatigue, frustration, and isolation, can decrease doctor visits. In addition, treating depression in patients with DJD may help reduce the amount of pain and improve their functional status and quality of life [41, 42].
14.5.1.6 Assistive Devices
While no research evidence exists regarding the use of specific shoes for hip DJD, both the ACR and EULAR recommend their use as low-risk interventions. EULAR specifies that appropriate shoes do not have a raised heel, have thick shock-absorbing soles, support for the arches of the foot, and a size big enough to allow comfortable space for the toes [21]. There is likewise no research evidence for appliances such as canes and walkers [6] in the treatment of hip DJD, but theoretically they may help to alter joint forces [6, 21]. In general, there are few contraindications if the device is found to be effective for individual patients.
14.5.1.7 Acupuncture
Evidence exists supporting the use of acupuncture in the management of chronic pain [43] and has specifically been studied in the treatment of DJD. A 2006 RCT of acupuncture and DJD found patients treated with acupuncture in addition to routine care to have significant improvement in symptoms and quality of life compared with patients who received routine care alone [44]. A 2014 systematic review and meta-analysis reaffirmed these conclusions [45]. Acupuncture is a safe intervention when administered by physicians, has a small potential for adverse events, and should be considered as adjuvant treatment for hip DJD [44].
14.5.2 Pharmacologic Therapy
Pharmacologic therapy in DJD should be undertaken as a supplement, not a replacement, for nonpharmacologic therapy. Drug therapy has been found to be most potent when combined with nonpharmacologic treatment. The majority of current pharmacologic options in the treatment of DJD are symptom-modifying therapies; however, structure- and disease-modifying therapies are currently in development.
Current symptom-modifying medications include analgesics (acetaminophen, opioids, and tramadol), nonsteroidal anti-inflammatory drugs (NSAIDs), COX-2 inhibitors, and intra-articular corticosteroid and viscosupplementation.
14.5.2.1 Acetaminophen
Several organizations consider acetaminophen, up to a maximum daily dose of 4000 mg, first line pharmacologic therapy for the management of hip DJD [19, 20], however, recent studies raise concerns about efficacy and safety. A 2006 Cochrane systematic review concluded that NSAIDs are superior to acetaminophen for pain control in DJD of the hip [46] and in 2009, an advisory committee of the US Food and Drug Administration recommended, but did not mandate, lowering the maximum total daily dose from 4000 mg to 3250 mg due to concerns about liver damage [47].
A 2015 meta-analysis and systematic review of studies evaluating a total of 3541 subjects over a period of up to 3 months concluded only minimal benefit (3.7 point improvement on a 0–100 point symptom and function scale) when used for management of hip DJD [48]. This analysis did not find any statistically significant difference between acetaminophen and placebo groups for participants reporting any adverse event or serious adverse events, but did find that the acetaminophen group was nearly four times as likely to have abnormal liver function tests (defined as 1.5 times the upper limit of normal) than the placebo group [48]. It is worth noting that a 2006 systematic review evaluating hepatotoxicity in acetaminophen-treated patients with baseline normal liver function found that low level, transient ALT elevations were shown to usually resolve or decrease with continued therapy and were not accompanied by signs of liver injury [49].
14.5.2.2 NSAIDs and COX-2 inhibitors
NSAIDs are widely used to control the pain of DJD. Expert opinion recommends that NSAIDs, at the lowest effective dose, should be added or substituted for patients who respond inadequately to acetaminophen. There is strong evidence that NSAIDs provide significant pain relief for DJD; however, they are also associated with significant side effects and risks, particularly adverse gastrointestinal (GI) events [6]. The practitioner should also be aware that these drugs now have a “Black Box Warning ” due to the risk for both cardiovascular and gastrointestinal serious side effects.
GI side effects associated with NSAID use are reported to lead to over $500 million annually in health care costs [50]. There is a 2–4 % annual incidence of serious GI ulcer and complications in NSAID users which is four times higher than in nonusers [51]. NSAIDs result in at least 7000 deaths annually in the USA attributed to GI side effects [52]. Therefore, NSAIDs should be prescribed with caution in patients over the age of 65 or with a history of peptic ulcer disease, upper GI bleed, oral glucocorticoid therapy, and anticoagulation. All patients should be counseled regarding the risks of NSAIDs. In patients with increased GI risk, nonselective NSAIDs plus a gastroprotective agent , or a selective COX-2 inhibitor should be used. These strategies are more expensive and only cost-effective in patients with greater GI risk [6].
Both NSAIDs and COX-2 inhibitors should be prescribed with caution for those with renal and cardiovascular disease. A healthy kidney is able to compensate from prostaglandin inhibition, but if baseline renal function is impaired, there is a high risk of acute kidney injury [53]. More recent studies assessing the cardiovascular risk of NSAIDs and COX-2 inhibitors have shown significantly increased risk of cardiovascular events such as myocardial infarction and stroke [54, 55]. It is worth noting that there is some evidence to suggest that naproxen offers the lowest risk of cardiovascular side effects [54, 55].
14.5.2.3 Opioids
Opioids offer a modest benefit over placebo in the treatment of DJD, however, the shortcomings of opioid therapy are several fold. The primary risks include dependence, addiction, and overdose. Furthermore, pain control associated with opioid use typically diminishes within 4 weeks of use [56].
Opioids may be appropriately prescribed in hip DJD as a bridging therapy to impending THR [56]. Extended release forms are preferable to immediate-release formulations at providing consistent stable analgesia. It may be necessary to switch opioid medications, one or more times to achieve an acceptable balance, between adverse events and analgesia as patients have variable responses to different opioids. Side effects with a dose–response relationship include nausea , vomiting, constipation, dizziness, somnolence, and pruritus.
14.5.2.4 Tramadol
Tramadol is an opioid agonist and centrally acting analgesic not chemically related to opioids. When taken up to 3 months for DJD, a Cochrane Review gave Tramadol gold level evidence for decreasing pain, and improving stiffness, function, and overall well-being [57]. A 2006 RCT demonstrated that Tramadol ER was effective for patients with knee or hip DJD with limited side effects [58].
Tramadol, in contrast to NSAIDs, does not cause GI bleeding, renal problems or aggravate hypertension and CHF. Compared with narcotics, tramadol does not have significant abuse potential. Common side effects from tramadol include nausea, vomiting , dizziness, sweating, constipation, tiredness, and headache.
14.5.2.5 Intra-Articular Injectable Therapy
Glucocorticoids and viscosupplementation are the most common intra-articular therapies used for hip DJD. Three primary techniques exist for intra-articular injections of the hip: landmark-guided injections (LMGIs) , fluoroscopically guided injections (FGIs) , and ultrasound-guided injections (USGIs) . Due to the deep location of the hip joint, injections should be performed under fluoroscopic or ultrasound guidance (Fig. 14.6). While both fluoroscopy and ultrasound are well tolerated, only ultrasound permits the rapid identification of soft tissue structures, notably the femoral neurovascular bundle, and is a radiation-free technique. Overall, the procedure is regarded as innocuous and safe [59]. Contraindications to joint injections include bacteremia, inaccessible joints, joint prosthesis, adjacent osteomyelitis, and overlying infection of the soft tissue.
