Knee Osteoarthritis

CHAPTER 70

Knee Osteoarthritis David M. Blaustein, MD Edward M. Phillips, MD

Synonyms Degenerative joint disease of the knee joint Degenerative arthritis Joint destruction of the knee Osteoarthrosis

ICD-10 Codes M17.0 M17.10 M17.11 M17.12 M17.4 M17.5 M12.561 M12.562 M12.569

Bilateral primary osteoarthritis of knee Unilateral primary osteoarthritis, unspecified knee Unilateral primary osteoarthritis, right knee Unilateral primary osteoarthritis, left knee Other bilateral secondary osteoarthritis of knee Other unilateral secondary osteoarthritis of knee Traumatic arthropathy, right knee Traumatic arthropathy, left knee Traumatic arthropathy, unspecified knee

Definition Osteoarthritis (OA) is steadily becoming the most common cause of disability for the middle-aged and has become the most common cause of disability for those older than 65 years.1 The knee joint is the most common site for lower extremity OA.2 It is estimated that nearly half of all adults will have symptomatic knee OA in their lifetimes.3 In addition to the growing population of elderly patients with knee OA, an increasing number of former athletes with previous knee injuries may experience post-traumatic knee OA. OA of the knee results from mechanical and idiopathic factors. Although OA is now known to be a complex condition involving the entire joint, the hallmark of OA is the alteration of the balance between degradation and synthesis of articular cartilage and subchondral bone. OA can involve any or all of the three major knee compartments: medial, patellofemoral, or lateral. The medial

compartment is most often involved, leading to medial joint space collapse and thus to a genu varum (bowleg) deformity. Lateral compartment involvement may lead to a genu valgum (knock-knee) deformity. Arthritis in one compartment may, through altered biomechanical stress patterns, eventually lead to involvement of another compartment. OA affects all structures within and around a joint. Hyaline articular cartilage is lost. Bone remodeling occurs, with capsular stretching and weakness of periarticular muscles. Synovitis is present in some cases and ligamentous laxity occurs. Lesions in the bone marrow may also develop. OA often involves the joint in a nonuniform and focal manner. Localized areas of loss of cartilage can increase focal stress across the joint, leading to further cartilage loss. With a large enough area of cartilage loss or with bone remodeling, the joint becomes tilted, and malalignment develops. Malalignment is the most potent risk factor for structural deterioration of the knee joint.4 By further increasing the degree of focal loading, malalignment creates a vicious circle of joint damage that ultimately can lead to joint failure. The role of obesity as a risk factor for knee OA has been well documented. A large, population-based prospective study found that the risk for knee OA was seven times greater for people with a body mass index of 30 or higher compared with those with a body mass index below 25.5 Moreover, women (of average height) who lost 5 kg of weight reduced their risk of symptomatic knee OA by 50%.6 Sports injuries and vigorous physical activity are considered to be important risk factors in knee OA. Athletes who take part in high-impact sports, such as soccer, ice hockey, and football, have an increased risk of knee OA.7 Knee OA is common in those performing heavy physical work, especially if this involves knee bending, squatting, kneeling, or repetitive use of joints.8 It is unclear if the association of knee OA with these work-related activities is secondary to the nature of the work or the increased likelihood of injury. 

Symptoms Knee OA is characterized by joint pain, tenderness, decreased range of motion, crepitus, occasional effusion, and inflammation of varying degrees. Initial OA symptoms are generally minimal, given the gradual and insidious onset of the condition. Pain typically occurs around the knee, particularly during weight bearing, tending to worsen later in the day and decreasing with rest. With progression of the disease, pain can persist even at rest. Pain may also radiate to adjacent sites, as OA indirectly alters the biomechanics 391

392

PART 1  MSK Disorders

of other anatomic structures such as ligaments, muscles, nerves, and veins. Joint stiffness may occur after periods of inactivity, such as after awakening in the morning or prolonged sitting. Patients often report higher pain levels in the morning, but usually for less than 30 minutes. Patients often experience limitation of movement because of joint stiffness or swelling. Many patients report a “locking” or a “catching” sensation (actual knee locking is often associated with meniscal tear [see Chapter 72]), which is probably due to a variety of causes, including debris from degenerated cartilage or meniscus in the joint known as a “loose body,” increased adhesiveness of the relatively rough articular surfaces, muscle weakness, and even tissue inflammation. Stiffness can discourage mobility. This initiates a cycle that results in deconditioning, decreased function, and increased pain. Barometric changes, such as those associated with damp, rainy weather, will often increase pain intensity.9 Patients often note that their knees “give way” or feel unstable at times. 

Physical Examination Examination of the patient includes testing for various possible causes of knee pain. Therefore the entire limb, from the hip to the ankle, along with the opposite limb, is examined. It is important to look for quadriceps weakness or atrophy, knee and hip flexion contractures, and foot abnormalities such as excessive pronation. Gait should be observed for presence of a limp, functional limb length discrepancy (with the arthritic limb often being shorter due to knee flexion contracture from OA), or buckling. Genu varum or valgum is often better appreciated when the patient is standing. The affected knee should be compared with the contralateral uninvolved knee. Knee examination may reveal decreased knee extension or flexion secondary to effusion or osteophytes (both of which may be palpable). Osteophytes along the femoral condyles may be palpated, especially along the medial distal femur. Palpation may reveal patellar or parapatellar tenderness. Crepitation, resulting from juxtaposition of roughened cartilage surfaces, may be appreciated along the joint line when the knee is flexed or extended. A mild effusion and tenderness may be appreciated along the medial joint line or at the pes anserine bursa. Ligament testing may reveal laxity of the collateral or cruciate ligaments. Lateral subluxation of the patella may be found in patients with genu valgum (Table 70.1). Another clue on examination that the patient probably has knee OA is the finding of visible bone enlargements (exostoses) of the fingers. The findings of the neurologic examination are typically normal, with the exception of decreased muscle strength, particularly in the quadriceps, due to disuse or guarding secondary to pain. 

Functional Limitations Individuals with knee arthritis may describe deficits in their ability to transfer from sit to stand, particularly from a low chair or in and out of a car. In addition, ascending and descending stairs, gait speed, and ability to walk long distances may be compromised. 

Table 70.1  Typical Physical Examination Findings in Knee Osteoarthritis Inspection

Bone hypertrophy Varus deformity from preferential medial compartment involvement

Palpation

Increased warmth Joint effusion Joint line tenderness

Range of motion

Painful knee flexion Decreased joint flexion secondary to pain Crepitus (coarse)

Joint stability

Mediolateral instability

Diagnostic Studies OA is diagnosed clinically on the basis of history and physical examination. Imaging, however, can be used to confirm the diagnosis and to rule out other conditions. Radiographic changes include joint space narrowing, subchondral sclerosis, and bone cysts in weight-bearing regions of the joint and osteophytes in low-pressure areas, especially along the marginal regions of the joint. Joint space narrowing is the initial finding, followed by subchondral sclerosis, then by osteophytes, and finally by cysts with sclerotic margins (known as synovial cysts, subchondral cysts, subarticular pseudocysts, or necrotic pseudocysts). Radiographic evidence of OA is not well correlated with symptoms; however, the presence of osteophytes and subchondral sclerosis had a strong association with knee pain, whereas the absence or presence of joint space narrowing was not associated with pain.10 Knee pain severity was a more important determinant of functional impairment than radiographic severity of OA.11 Indications for plain x-ray films include trauma, effusion, symptoms not readily explainable by physical examination findings, severe pain, presurgical planning, and failure of conservative management. Recommended films are weight-bearing (standing) anteroposterior, lateral, and patellar views. Radiographs taken during weight bearing with the knee in full extension and partial flexion may reveal a constellation of findings associated with OA, including asymmetric narrowing of the joint space (typically medial compartment), osteophytes, sclerosis, and subchondral cysts (Fig. 70.1). A Merchant view specifically evaluates the patellofemoral space and patellar tilt. Non-weight-bearing lateral views may help in the evaluation of the patellofemoral and tibiofemoral joint spaces. Tunnel views can help visualize loose osteochondral bodies. Magnetic resonance imaging (MRI) usually adds little but cost to the evaluation of OA of the knee. Although it may reveal early OA changes, MRI is not indicated in the initial evaluation of older persons with chronic knee pain. MRI may detect incidental findings, such as meniscal tears, that are common in middle-aged and older adults with and without knee pain. Musculoskeletal ultrasonography (MUS) has potential for detecting bone erosions, synovitis, tendon disease, and enthesopathy. It has a number of distinct advantages over MRI, including good patient

CHAPTER 70  Knee Osteoarthritis

393

tolerability and ability to scan multiple joints in a short time. Although there is not an abundance of data, there are now several studies showing good reliability and validity of MUS in detecting knee OA.12 However, there remains limited data describing standardized scanning methodology and standardized definitions of ultrasound pathologic changes. Laboratory test results are typically normal, but analysis may be undertaken, especially for elderly patients, to establish a baseline (e.g., blood urea nitrogen concentration, creatinine concentration, or liver function tests before use of nonsteroidal anti-inflammatory drugs or acetaminophen) or to exclude other conditions such as rheumatoid arthritis. Synovial fluid analysis should not be undertaken unless destructive, crystalline, or septic arthritis is suspected.  Differential Diagnosis Common Causes of Knee Pain by Age Group Children and adolescents

Adults

Older adults

Patellar subluxation Osgood-Schlatter disease Patellar tendinitis/patellofemoral pain Referred pain (e.g., slipped capital femoral epiphysis) Osteochondritis dissecans Subchondral fracture Genetic or congenital defect Septic arthritis Tumor Patellofemoral pain syndrome (chondromalacia patellae) Medial plica syndrome Pes anserine bursitis Trauma: ligamentous sprains Meniscal tear Inflammatory arthropathy: rheumatoid arthritis, Reiter syndrome Septic arthritis Midlumbar radiculopathy Tumor OA Crystal-induced inflammatory arthropathy: gout, pseudogout Rheumatoid arthritis Popliteal cyst Tumor

Differential Diagnosis of Knee Pain by Anatomic Site Anterior knee Patellar subluxation or dislocation/ten­ pain dinitis Jumper’s knee Tibial apophysitis (Osgood-Schlatter lesion) Quadricep tendinitis Patellofemoral pain syndrome (chondromalacia patellae) Medial knee Medial collateral ligament sprain pain Medial meniscal tear Pes anserine bursitis Medial plica syndrome Lateral knee Lateral collateral ligament sprain pain Lateral meniscal tear Iliotibial band tendinitis Posterior knee Popliteal cyst (Baker cyst) pain Posterior cruciate ligament injury OA, Osteoarthritis.

FIG. 70.1  Knee radiograph demonstrating osteophytes (arrows) and medial joint space narrowing consistent with degenerative arthritis. (From West SG. Rheumatology Secrets. Philadelphia: Hanley & Belfus; 1997.)

Treatment Initial The PRICE regimen may help provide initial relief for patients in pain: protection with limited weight bearing by using a cane or modification of exercise to reduce stress; relative rest (or taking adequate rests throughout the day, avoiding prolonged standing, climbing of stairs, kneeling, deep knee bending); ice (applied while the skin is protected with a towel for up to 15 minutes at a time several times a day; note, however, that some patients with chronic pain may find better relief with moist heat); compression (if swelling exists, wrapping with an elastic bandage or a sleeve may help); and elevation (may help diminish swelling, if it is present). There are a wide variety of initial treatment options for knee arthritis. Current guidelines put forth by the American College of Rheumatology suggest the use of acetaminophen as a first-line therapy for OA,13 followed by oral and topical nonsteroidal anti-inflammatory drugs. Prior recommendations of topical capsaicin cream and nutritional intervention, such as glucosamine sulfate and chondroitin sulfate, are no longer in place. Orthotics and footwear modifications are also included in the list of treatment options and are discussed further in the next section. 

Rehabilitation Exercise Exercise is the mainstay of non-pharmacologic and nonsurgical treatment of knee OA. A recent meta-analysis showed exercise to be equally effective to oral analgesics in knee OA.14 Randomized studies definitively support the benefits of exercise (even if it is home based) on pain, function, and quality of life in patients with knee OA.15 Because there is currently no cure for OA, most research continues to evaluate the use of exercise as a treatment to alleviate symptoms of the disease and to enhance functional capacity. Exercise programs for knee OA typically consist of (1) lower extremity stretching, (2) lower extremity strengthening focusing on the quadriceps but also with attention to

394

PART 1  MSK Disorders

the hamstrings and hip muscles, (3) aerobic conditioning with a stationary bike, treadmill, water aerobics, or elliptical trainer, and (4) balance and proprioceptive exercises or perturbation exercises. Although isotonic, isometric, isokinetic, and aerobic exercise have all been shown to improve pain, disability, and walking speed, there are conflicting findings on the superiority of one over another with no general consensus.16 The exact amount of resistance and number of repetitions has not been quantified for the treatment of knee OA, but one recent meta-analysis showed that individuals with knee OA who followed the American College of Sports Medicine guidelines for strengthening achieved greater gains in lower extremity strength than individuals who didn’t follow these guidelines. The suggested guidelines consist of using an external load greater than 40% of one repetition maximum for 8 to 12 repetitions in 2 to 4 sets.17 It is important to understand the waxing and waning nature of arthritis symptoms in the knee and be flexible in adjusting the resistance used based upon pain and episodic arthritic flares. For patients with greater pain, this can be done with static exercise such as isometric quad sets or aquatic exercise programs. Closed kinetic chain exercises such as lunges and wall slides are preferable to open chain exercises, as they allow more controlled motion at the knee. The resistance should slowly be increased with time if possible and use of ice should be employed to manage pain during treatment. Exercise bicycles and walking should be recommended to enhance aerobic capacity. Deep knee bends in the presence of effusion should be avoided. Particular attention must be paid to strengthening of the medial quadriceps in patients with genu valgum who have lateral subluxation of the patella. Maintaining activity is critical to maintaining function. Even those patients scheduled for total knee arthroplasty should pursue static and dynamic strengthening as well as cardiovascular conditioning preoperatively to ease postoperative rehabilitation.18 Newer approaches are being employed in the treatment of OA, including Tai Chi, which was shown to be equally effective to standardized PT in a recent randomized trial,19 and whole body vibration (WBV). This latter technique has patients stand on a vibrating plate, which in turn is purported to stimulate muscles and tendons and improve neuromuscular performance. No quality randomized trials have been done yet on the effect of WBV on knee OA.20 

Therapeutic Modalities Transcutaneous electrical nerve stimulation, the application of an electrical current through the skin with the aim of pain modulation, is a frequently used modality in knee OA. Although this is a popular treatment option, research supporting its efficacy is lacking.21 Additional therapeutic modalities, such as electrical stimulation or massage, may also be used. Therapists may also review postural alignment and joint positioning techniques, especially for when the patient is sleeping. In particular, the use of a pillow under bent knees, much favored by many patients when they are supine, should be avoided because resulting knee flexion contractures, even if small, can significantly increase stresses on the knee during gait. Stretching of the hamstrings and quadriceps may also prove

beneficial. Patients should be counseled against prolonged wearing of high heels, which is associated with medial knee OA.22

Adaptive Equipment Adaptive equipment, such as a cane or walker, can reduce hip or knee loading, thereby reducing pain. It may also reduce fall risk in patients with impaired balance. Proper training in the use of a cane is important because it reduces joint loading in the contralateral hip but amplifies forces in the ipsilateral hip. 

Bracing and Footwear The basic rationale for a knee brace for unicompartmental knee OA is to improve function by reducing the patient’s symptoms. This can be accomplished, in theory, by reducing the biomechanical load on the affected compartment of the knee. A review of the published literature on knee bracing for OA points out limitations of clinical trials to date, but acknowledges limited evidence for improvement in pain and function in patients using OA braces.23 In patients with OA and varus malalignment of the knees, a shoe wedge (thicker laterally) moves the center of loading laterally during walking, a change that extends from foot to knee, lessening medial load across the knee. Although such modifications to footwear decrease varus malalignment, studies show no reduction in pain compared with a neutral insert in patients with medial compartment knee OA.23 Tilting or malalignment of the patella may cause patellofemoral pain. Patellar realignment with the use of braces or tape to pull the patella back into the trochlear sulcus of the femur or to reduce its tilt may lessen pain. In clinical trials with tape to reposition the patella into the sulcus without tilt, knee pain, range of motion, and proprioception was improved compared to placebo.24 However, patients may find it difficult to apply tape, and skin irritation is common. Commercial patellar braces are also available, but their efficacy has not been studied formally. Heel lifts or built-up shoes may be required in the presence of leg length discrepancy to prevent compensatory knee flexion gait on the longer side. In the presence of knee deformity, therapists can also evaluate for altered biomechanics (e.g., genu varum may lead to femoral internal torsion, resulting in compensatory external rotation of the tibia, which predisposes the patient to increased arthritic changes). Therapists can also visit the homes and workplaces of patients to suggest adjustments, such as raised toilet seats, grab bars, reachers, and the like. 

Procedures Intra-articular corticosteroid injections may help in reduction of local inflammation and improvement of symptoms. Hence, selection of patients with suspected knee inflammation tends to yield a better response to these injections. The response is generally rapid, but may not be sustained in the longer term. A systematic review of intra-articular corticosteroid injections demonstrated evidence of pain reduction up to six weeks following injection.25 Because the corticosteroid is delivered directly, systemic toxicity is minimized. Although intra-articular corticosteroid injections have not

CHAPTER 70  Knee Osteoarthritis

Table 70.2  Minimizing Potential Side Effects of Intra-articular Corticosteroid Injection Side Effect

Ways to Minimize Risk

Systemic effects

Avoid high doses and multiple simultaneous injections; use accurate injection techniques

Tendon rupture, fat atrophy, muscle wasting, skin pigment changes

Avoid misdirected injections. Consider musculoskeletal ultrasound for guidance

Septic arthritis

Use sterile technique; withhold therapy in at-risk patients

Nerve and blood vessel damage

Use accurate injection techniques

Postinjection symptom flare or synovitis

Avoid the same preparation for future injections

Flushing

Avoid high doses

Anaphylaxis

Take careful drug allergy history

Steroid arthropathy

Avoid high doses and overly frequent injections

Synovial cavity

Patella

395

available in several forms with different molecular weights. The rationale for using viscosupplementation is to impart protective properties to synovial fluid, including shock absorption, energy dissipation, and lubrication of the articular cartilage surface. Hyaluronate can be administered in a series of three weekly injections (2-mL vials or prefilled syringes) or in higher volume single-injection form. Treatments are typically repeated two to three times per year. Clinical trials of viscosupplementation have demonstrated limited efficacy in pain relief.26 Compared with corticosteroid injection, the effect of hyaluronic acid appears to be less dramatic but more durable. In a meta-analysis comparing both interventions, hyaluronic acid was less effective for pain relief in the first 4 weeks after injection. By week 4, the two approaches had equal efficacy. Beyond week 8, hyaluronic acid had a greater effect.27 Side effects included local inflammation and increased pain at the injection site. There is no evidence that hyaluronan injection in humans alters biologic processes or progression of cartilage damage. The hyaluronic acid is injected into the knee in the same manner as the intra-articular steroid is administered. Patients should be told that they may not see any clinical improvement until up to five weeks following injection(s). There is no evidence that one brand of a viscosupplement is superior to another in terms of efficacy.28 Acupuncture, a technique in existence for thousands of years, has gained renewed interest as a treatment of OA; however, there is conflicting evidence regarding its effectiveness in treatment of knee OA. A meta-analysis showed that sham acupuncture had the same effect as acupuncture and therefore a placebo effect is felt to be playing a role.29 The ACR conditionally recommends the use of acupuncture in chronic moderate to severe OA when surgical intervention is not possible.

Biologics

FIG. 70.2  Location for needle insertion.

been shown to cause cartilage damage, they are generally not given >3 times per year. Given the short-term effect and limitation on injection frequency, corticosteroid injection is most often used as an adjunctive therapy for acute or severe symptom flares. Table 70.2 lists potential systemic side effects of corticosteroid injections. Administration of steroids through iontophoresis may be an alternative for patients hesitant to undergo injections. Intra-articular knee injections can be done using six different approaches, including medial and lateral suprapatellar, medial and lateral mid patellar, and medial and lateral anterior patellar. The latter two approaches are performed with the knee in a flexed position and the former approaches with the knee extended. Learning two different approaches is optimal since arthritic changes may be asymmetric, making it more difficult to enter a region of the joint with more prominent joint space narrowing or osteophytes. An alternative entry point is then available to the clinician performing the injection. Fig. 70.2 details one injection technique. Viscosupplementation with hyaluronic acid, available as naturally occurring hyaluronan, is now commercially

The use of PRP injections for various musculoskeletal injuries has expanded over the past two decades and knee OA is among the leading diagnoses that this procedure has been used to treat. The procedure involves drawing a patient’s blood and spinning it down in a centrifuge to separate out platelets from other blood products, including plasma. A small amount of autologous plasma is combined with these highly concentrated platelets in a solution that is subsequently injected into degenerated joints or tendons. Platelets contain various growth factors and cytokines that are thought to jumpstart the healing process and promote tissue regeneration in several ways, including stimulating cell replication, promoting angiogenesis, and stimulating the inflammatory cascade in chronic musculoskeletal conditions.30 A recent meta-analysis of PRP injections in the treatment of knee OA looked at 10 randomized trials showing that PRP and viscosupplementation had similar therapeutic effect 6 months postinjection, but that PRP had superior pain relief and functional improvement 1 year postinjection.31 Although these early findings are promising, further studies need to be done to confirm the efficacy of this procedure. PRP injections are not covered by insurance and no specific indications have been identified for its use. In general, this procedure is more effective in mild to moderate OA and has been used when all other conservative treatment for OA has been ineffective or when knee replacement surgery is contraindicated. 

396

PART 1  MSK Disorders

Table 70.3  Surgical Options for Osteoarthritis of the Knee Established Techniques

Indications

Outcome

Arthroscopic débridement

Meniscal signs and symptoms Synovitis Osteophytic impingement Catching or locking caused by loose bodies

Most reports show improvement in 50% to 80% of patients; however, results deteriorate with time

Osteotomy of the proximal tibia or distal femur

Predominantly medial compartment involvement

Recovery is prolonged Relief of symptoms often incomplete

Unicompartmental knee replacement

Predominantly medial compartment involvement Minimal lateral compartment disease No major anterior knee pain Stable knee joint Correctable varus deformity Fixed flexion deformity of less than 10 degrees

Survivorship rate for implants of 90% at 20 years

Patellofemoral replacement

Isolated patellofemoral joint involvement

Results have been variable

Total knee replacement

Tricompartmental disease

Survival rates of between 84% and 98% at 15 years

Technology While total knee replacement (TKR) remains the mainstay for severe multicompartmental DJD, advances in patellofemoral arthroplasties may help younger patients with isolated patellofemoral arthritis avoid the more radical procedure. If patients are screened carefully to ensure that the patellofemoral arthritis is indeed the source of symptoms, then patellofemoral replacement is a viable option. Firstgeneration patellofemoral arthroplasties had high failure rates due to patellar maltracking, with the main long-term complication being progression of tibiofemoral joint arthritis. However, more contemporary designs have addressed the tracking issues and have resulted in improved short- and mid-term outcomes. The durability of these prostheses remains uncertain, however, and longer-term studies are lacking.32 

Surgery (Table 70.3) Arthroscopic débridement includes lavage and the removal of loose bodies, debris, mobile fragments of articular cartilage, unstable torn menisci, and impinging osteophytes. However, it is clear from the literature that drilling, abrasion chondroplasty, microfracture, saucerization, notchplasty, osteophyte removal, synovectomy, and arthrolysis are also performed simultaneously in many clinical series. Patients who have a short history and a sudden onset of mechanical symptoms and also have knee effusions are likely to do best.33 Meniscal symptoms and signs, synovitis or synovial impingement, osteophytic impingement, and catching or locking caused by loose bodies favor a good outcome. Significant instability and malalignment are poor prognostic factors. Patients who have radiographic signs of advanced degeneration are unlikely to benefit.34 Although arthroscopic surgery has been widely used for OA of the knee, scientific evidence to support its efficacy is lacking. Most of the orthopedic literature supporting its use is based on retrospective studies. However, in a randomized, controlled trial, arthroscopic surgery for OA of

the knee provided no additional benefit to optimized physical and medical therapies.35 Up to a quarter of patients with knee OA have predominant involvement of the medial compartment. The surgical options for such patients who are younger and active remain somewhat controversial and include medial unicompartmental knee replacement (UKR), proximal tibial or distal femoral osteotomy, and TKR (see Chapter 80). Osteotomy is a less drastic measure than knee replacement, as it preserves the knee joint and is often favored by younger, active patients with unicompartmental symptoms. In osteotomy, a wedge-shaped piece of bone is removed from either the femur or tibia to bring the knee joint back into a more physiologic alignment. This procedure moves the weight-bearing axis to the less damaged compartment. Recovery is prolonged and relief of symptoms often incomplete, but osteotomy may delay or even avoid the need for TKR.36 Successful treatment could allow a return to sport. The risks specific to this surgery depend on the technique and include nonunion at the osteotomy site, common peroneal nerve injury, pain from the proximal tibiofibular joint, and overcorrection or undercorrection of the deformity. An ongoing debate within the orthopedic community concerns the relative merits of high tibial osteotomy compared with UKR in younger patients. A meta-analysis comparing these two procedures did not show significant benefit of one method over another,37 although UKR patients tend to recover more quickly and have better knee motion. UKR has now become an accepted treatment for older patients with medial compartment arthritis. The prerequisites for a UKR include stability of the joint, correctable varus deformity, fixed flexion deformity of less than 10 degrees, and minimal lateral compartment disease. The results of UKR in lateral compartment disease have yet to be fully determined. Wear of the polyethylene prosthesis in UKR is also an issue, but the ability to retain the anterior and posterior cruciate ligaments is an advantage that UKR has over TKR.38 TKRs, with a quarter-century track record, have generally provided most patients with good

CHAPTER 70  Knee Osteoarthritis

pain relief. Severe chondromalacia may necessitate patellectomy (patella excision). Knee arthrodesis (fusion) today is generally reserved for patients in whom knee replacement surgery fails and are of relatively younger age with higher functional levels and poor knee extension. Other less commonly used surgical options, such as synovectomy and small prostheses (to correct deformity), are also possible. 

Potential Disease Complications Progressive knee OA may result in reduced mobility and the general systemic complications of immobility and deconditioning. Antalgic gait can result in contralateral hip disease (e.g., greater trochanteric bursitis). The risk of falls will be increased by decreased mobility at the knee. Complaints of chronic pain may result from the initial knee OA if it is inadequately treated. 

Potential Treatment Complications Complications of anti-inflammatory medication and steroid injections are well known. Infection is a rare but possible result of joint injection or surgery. Cryotherapy or heat therapy can, of course, lead to frostbite or burns. Hyaluronic acid injections may result in localized transient pain or effusion. Arthroscopy may damage the articular surface membrane, thus initiating damage to uninvolved cartilage. Excessive arthroscopic scraping has sometimes been associated with persistent pain. The possibility of infection and deep venous thrombosis (DVT) and the small but real possibility of intraoperative mortality limit the use of surgery to a lastline option. There is still debate regarding routine perioperative use of anticoagulation and it has been suggested that this decision be tailored to the individual patient’s risk factors. One recent large population-based case control study confirmed the higher risk of DVT after knee arthroscopy and showed ligament reconstruction further increases risk of DVT. Low-molecular-weight heparin was not found to decrease DVT risk.39 Mechanical wear and prosthesis loosening, especially for cemented prostheses, often lead to the need for revision after a decade or so.

References 1. Bashaw RT, Tingstad EM. Rehabilitation of the osteoarthritic patient: focus on the knee. Clin Sports Med. 2005;24:101–131. 2. Hootman J, Bolen J, Helmick C, Langmaid G. Prevalence of doctor-diagnosed arthritis and arthritis-attributable activity limitation—United States, 2003-2005. MMWR Morb Mortal Wkly Rep. 2006;55:1089–1092. 3. Murphy L, Schwartz TA, Helmick CG, et al. Lifetime risk of symptomatic knee osteoarthritis. Arthritis Rheum. 2008;59:1207–1213. 4. Sharma L, Song J, Felson DT, et al. The role of knee alignment in disease progression and functional decline in knee osteoarthritis. JAMA. 2001;286:188–195. 5. Toivanen AT, Heliövaara M, Impivaara O, et al. Obesity, physically demanding work and traumatic knee injury are major risk factors for knee osteoarthritis—a population-based study with a follow-up of 22 years. Rheumatology (Oxford). 2010;49:308–314. 6. Pai Y-C, Rymer WZ, Chang RW, et al. Effect of age and osteoarthritis on knee proprioception. Arthritis Rheum. 1997;40:2260–2265. 7. Driban J, Hootman JM, Sitler MR, Harris KP, Cattano NM. Is participation in certain sports associated with knee arthritis? A systematic review. J Athl Train. 2017;52(6):497–506. 8. Hunter DJ, March L, Sambrook PN. Knee osteoarthritis: the influence of environmental factors. Clin Exp Rheumatol. 2002;20: 93–100.

397

9. McAlindon T, Formica M, Schmid CH, Fletcher J. Changes in barometric pressure and ambient temperature influence osteoarthritis pain. Am J Med. 2007;120(5):429–434. 10. Szebenyi B, Hollander AP, Dieppe P, Quilty B, Duddy J, Clarke S, Kirwan JR. Associations between pain, function and radiographic features in osteoarthritis of the knee. Arthritis Rheum. 2006;54(1):230–235. 11. Bruyere O, Honore A, Giacovelli G, et al. Radiologic features poorly predict clinical outcomes in knee osteoarthritis. Scand J Rheumatol. 2002;31:13–16. 12. Razek AAKA, El-Basyouni SR. Ultrasound of knee osteoarthritis: interobserver agreement and correlation with Western Ontario and MacMaster Universities Osteoarthritis. Clin Rheumatol. 2016;35(4): 997–1001. 13. Hochberg MC, Altman RD, April RT, et al. American College of Rhematology 2012 recommendations for the use of nonpharmacologic and pharmacologic therapies in osteoarthritis of the hand, hip, and knee. Arthritis Care Res. 2012;64(4):465–474. 14. Henriksen M, Hansen JB, Klokker L, Bliddal H, Christensen R. Comparable effects of exercise and analgesics for pain secondary to knee osteoarthritis:a meta-analysis of trials included in Cochrane systematic reviews. J Comp Eff Res. 2016;5(4):417–431. 15. Fransen M, McConnell S, Harmer AR, Van der Esch M, Simic M, Bennell KL. Exercise for osteoarthritis of the knee. Cochrane Database Syst Rev. 2015;1:CD004376. 16. Huang MH, Lin YS, Yang RC, Lee CL. A comparison of various therapeutic exercises on the functional status of patients with knee osteoarthritis. Semin Arthritis Rheum. 2003;32(6):398–406. 17. Bartholdy C, Juhl C, Christensen R, Lund H, Zhang W, Henriksen M. Comparing clinical outcomes of exercise interventions according to the American College of Sports Medicine guidelines for strength training to other types of exercise in knee osteoarthritis: a systematic review and meta-analyses. Osteoarthr Cartil. 2016;24:S483–S484. 18. Swank AM, Kachelman JB, Bibeau W, et al. Prehabilitation before total knee arthroplasty increases strength and function in older adults with severe osteoarthritis. J Strength Cond Res. 2011;25:318–325. 19. Wang C, Schmid CH, Iversen MD, et al. Comparative effectiveness of Tai Chi versus physical therapy for knee osteoarthritis: a randomized trial. Ann Intern Med. 2016;165(2):77–86. 20. Xin L, Wang XQ, Chen BL, Huang LY, Liu Y. Whole body vibration exercise for knee osteoarthritis: a systematic review and meta-analysis. Evid Based Complement Alternat Med. 2015;2015:758147. 21. Palmer S, Domaille M, Cramp F, et al. Transcutaneous electrical nerve stimultion as an adjunct to education and exercise for knee osteoarthritis: a randomized controlled trial. Arthritis Care Res. 2014;66(3):387–394. 22. Kerrigan D, Todd M, O’Reilly P. Knee osteoarthritis and high heeled shoes. Lancet. 1998;351:1399–1401. 23. Duivenvoorden T, Brouwer RW, van Raaij TM, Verhagen AP, Verhaar JA, Bierma-Zeinstra SM. Braces and orthoses for osteoarthritis of the knee. Cochrane Database Syst Rev. 2015;3:CD004020. 24. Cho HY1, Yoon YW. Kinesio taping improves pain, range of motion and proprioception in older patients with knee osteoarthritis: a randomized controlled trial. Am J Phys Med Rehabil. 2016;95(1):e7–8. 25. da Costa, Bruno R, Jüni P. Intra-articular corticosteroids for osteoarthritis of the knee. JAMA. 2016;316(24):2671–2672. 26. Rutjes AW, Jüni P, da Costa BR, et al. Viscosupplementation for osteoarthritis of the knee: a systematic review and meta-analysis. Ann Intern Med. 2012;157:180–191. 27. Bannuru RR, Natov NS, Obadan IE, et al. Therapeutic trajectory of hyaluronic acid versus corticosteroids in the treatment of knee osteoarthritis: a systematic review and meta-analysis. Arthritis Rheum. 2009;61:1704–1711. 28. Gigis I, Fotiadis E, Nenopoulos A, Tsitas K, Hatzokos I. Comparison of two different molecular weight intra-articular injections of hyaluronic acid for the treatment of knee osteoarthritis. Hippokratia. 2106;20(1):26–31. 29. Manheimer E, Linde K, Lao L, Bouter LM, Berman BM. Meta-analysis: acupuncture for osteoarthritis of the knee. Ann Intern Med. 2007;146(12):868–877. 30. Sampson S, Gerhardt M, Mandelbaum B. Platelet rich plasma injection grafts for musculoskeletal injuries: a review. Curr Rev Musculoskelet Med. 2008;1(3):165–174. 31. Dai WL, Zhou AG, Zhang H, Zhang J. Efficacy of platelet–rich plasma in the treatment of knee osteoarthritis arthroscopy. Arthroscopy. 2017;33(3):659–670. 32. Lustig S. Patellofemoral arthroplasty. Orthop Traumatol Surg Res. 2014;100(1):S35–43.

398

PART 1  MSK Disorders

33. Day B. The indications for arthroscopic débridement for osteoarthritis of the knee. Orthop Clin North Am. 2005;36:413–417. 34. Felson DT, Buckwalter J. Débridement and lavage for osteoarthritis of the knee. N Engl J Med. 2002;347:132–133. 35. Kirkley A, Birmingham TB, Litchfield RB, et al. A randomized trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med. 2008;359:1097–1107. 36. Bonasia DE, Governale G, Spolaore S, Rossi R, Amendola A. High tibial osteotomy. Curr Rev Musculoskelet Med. 2014;7(4):292–301.

37. Fu D, Li G, Chen K, Zhao Y, Hua Y, Cai Z. Comparison of high tibial osteotomy and unicompartmental knee arthroplasty in the treatment of unicompartmental osteoarthritis. J Arthroplasty. 2013;28(5):759–765. 38. Parratee S, Argenson JN, Pearce O, Pauly V, Auquier P, Aubaniac JM. Medial unicompartmental knee replacement in the under-50s. Bone Joint J. 2009;91(3):351–356. 39. van Adrichem RA, Nelissen RG, Schipper IB, Rosendaal FR, Cannegieter SC. Risk of venous thrombosis after arthroscopy of the knee: results from a large population-based case-control study. J Thromb Haemost. 2015;13(8):1441–1448.