Complications and Outcomes of Nonoperative Treatment Modalities in Knee Osteoarthritis

Introduction

Osteoarthritis is a slowly progressive degenerative disorder that involves damage to joint cartilage, structural changes in the bone, and inflammation of the soft tissues surrounding the joint. Osteoarthritis of the knee is the most prevalent form of osteoarthritis, symptomatically affecting 13% of women and 10% of men greater than 60 years old. ^, Knee osteoarthritis can threaten a patient’s ability to participate in healthy physical activity and may predispose patients to medical comorbidities and a potential loss of independence secondary to the pain and disability associated with knee arthritis.

Unfortunately, there is currently no curative treatment for osteoarthritis. As such, all nonsurgical interventions for knee osteoarthritis are palliative rather than curative. The management goals of nonoperative care should include reducing knee pain, improving daily functioning, and potentially delaying disease progression. Treatment of knee osteoarthritis includes both nonsurgical and surgical options, with the primary surgical option being either a partial (unicompartmental knee arthroplasty [UKA]) or total knee arthroplasty (TKA). Published reports have consistently described TKA as an efficacious and cost-effective means of alleviating pain, restoring function, and improving health-related quality of life. However, because it is an invasive surgical treatment, it is associated with potentially serious intraoperative and postoperative risks. Therefore, only after nonsurgical treatments have failed should TKA be considered.

In 2013, the American Academy of Orthopaedic Surgeons (AAOS) released an updated version of evidence-based guidelines regarding treatment of knee osteoarthritis ( Table 5.1 ). These guidelines are based on a systematic review of current scientific and clinical research. Strong recommendations included generalized strengthening, low-impact aerobic exercise, neuromuscular education, nonsteroidal antiinflammatory drugs (NSAIDs; oral or topical), and tramadol. Moderate recommendations included weight loss if the patient’s body mass index (BMI) is greater than 25. Inconclusive recommendations included electrotherapeutic modalities, manual or active release therapy, valgus-directing force brace, acetaminophen, opioids, pain patches, platelet-rich plasma, and arthroscopic partial meniscectomy. Of importance, these guidelines were inconclusive regarding intraarticular corticosteroids and strongly recommended against hyaluronic acid injections and glucosamine and chondroitin supplementation. However, when considering different treatment modalities for knee osteoarthritis, the orthopaedic surgeon must balance scientific evidence, personal clinical experience, and each patient’s individualized values and preferences. This will allow for shared patient and surgeon decision-making and optimal patient satisfaction. Specific nonsurgical treatment options will be discussed later, organized specifically by AAOS recommendations.

TABLE 5.1

Summary of 2013 AAOS Clinical Practice Guidelines: Treatment of Osteoarthritis of the Knee

Strength of Recommendation
Strong	Strengthening, low-impact aerobic exercises
	Nonsteroidal antiinflammatory drugs or tramadol
	Cannot recommend acupuncture
	Cannot recommend glucosamine and chondroitin
	Cannot recommend hyaluronic acid
	Cannot recommend arthroscopy and lavage and debridement
Moderate	Weight loss if body mass index >25
	Cannot recommend lateral wedge insoles
	Cannot recommend needle lavage
Inconclusive	Physical agents (electrotherapeutic modalities)
	Manual therapy
	Valgus-directing force brace
	Acetaminophen, opioids, pain patches
	Intraarticular corticosteroids
	Growth factor or platelet-rich plasma injections
	Arthroscopic partial meniscectomy

AAOS , American Academy of Orthopaedic Surgeons.

Nonoperative Treatment Modalities: Strong Recommendation

Aerobic Exercise and Strength Training

Chronic pain from knee osteoarthritis can inhibit neural pathways to the surrounding musculature of the knee joint, resulting in a decrease of muscle activation and muscle mass leading to physical deconditioning and decreased quality of life. The quadriceps muscles absorb limb loading and help provide dynamic joint stability. Therefore, quadriceps weakness and abnormal mechanical joint forces have been related to the progression of knee osteoarthritis, and both are potentially modifiable by resistance training. Resistance exercises along with aerobic exercises have been illustrated to decrease pain and improve overall physical function in patients with knee osteoarthritis. Strength training administered in a variety of modes and intensities is both tolerable and effective in patients with knee osteoarthritis. It can ultimately lead to an improvement in muscle strength, walking self-efficacy, walking endurance, gait speed, stair climb/descent time, balance, and self-reported disability. In regard to aerobic exercises, walking programs, aquatic exercises, jogging in water, yoga, and tai chi have all been found to improve the function, gait pattern, and pain in patients with knee osteoarthritis. ^,

Important points regarding exercise programs for patients with knee osteoarthritis include the following: (1) supervised group or individualized treatments are superior to independent exercise; (2) targeting quadriceps, hamstrings, and hip abductors for strengthening; (3) minimizing compressive joint forces; and (4) the use of a combination of strengthening, flexibility, and functional exercises. In addition, for obese patients or those with more severe degenerative changes, hydrotherapy (also known as aqua therapy ) has been found to be an effective way to strengthen muscles while minimizing joint loading. Although exercise is associated with a reduction in pain and disability for patients with knee osteoarthritis, these improvements persist only if the exercise is continued. Therefore, orthopaedic surgeons must explain to their patients that long-term involvement in exercise is necessary to maintain any clinical improvements. In addition, patients must be educated regarding the fact that exercise has not been found to prevent knee osteoarthritis. Even with consistent resistance training and aerobic exercise, patients’ pain and function may ultimately deteriorate due to the natural course of knee osteoarthritis. However, exercise regimens should still be encouraged because of the proven short-term efficacy.

Nonsteroidal Antiinflammatory Drugs

NSAIDs are commonly used for the nonoperative treatment of knee osteoarthritis. The primary effect of NSAIDs is cyclooxygenase inhibition, blocking the formation of prostaglandins, prostacyclins, and thromboxanes. The cyclooxygenase enzyme (COX) exists in two forms: COX-1 and COX-2. COX-1 is expressed in platelets, the gastrointestinal (GI) tract, and the kidneys to regulate platelet function, gastric mucosa integrity, and renal blood flow. COX-2 synthesized prostaglandins potentiate pain sensation on the central and peripheral nervous system.

There are many studies demonstrating both short- and long-term effectiveness of NSAIDs in terms of decreasing the pain associated with osteoarthritis, and patients are able to take these medications in combination with other medications (such as acetaminophen) to further potentiate pain control. A list of NSAIDs commonly used in the United States is provided in Table 5.2 . Of course, NSAIDs are not without potential side effects, such as platelet inhibition, inhibition of prostaglandin formation needed for normal GI and renal function, cardiotoxicity, and drug-induced asthmatic reactions. NSAIDs should be used at the lowest effective dose and for the shortest duration. It is vital to consider patient medical comorbidities when deciding on this treatment. For example, patients with a history of prior GI events or cardiovascular or renal impairment may want to avoid NSAIDs or strictly monitor and regular their use. In addition, orthopaedic surgeons must be aware that NSAIDs have dangerous interactions with various drugs, including anticoagulants, antihypertensive agents, antidepressants, and lithium.

TABLE 5.2

Common Nonsteroidal Antiinflammatory Drugs ^, ^,

Drug Name	Characteristics & Dosing
Nonselective COX inhibitors	Potential side effects include excessive bleeding, gastrointestinal tract irritation/ulceration
Aspirin	Irreversibly inhibits platelet function for the life of the platelet (7–10 d) 325–650 mg q 4–6 h
Ibuprofen	Synergistically potentiates analgesic properties of hydrocodone and oxycodone, shorter duration of effect 200–400 mg q 4–6 h
Naproxen	Synergistically potentiates analgesic properties of hydrocodone and oxycodone 250–500 mg q 12 h
Diclofenac	Also available as topical patch/gel for treatment of osteoarthritis 50 mg q 8 h
Indomethacin	More frequently associated with CNS side effects (headache) 25–5 0 mg q 8–12 h
Selective COX-2 inhibitors	Significantly decreased risk of gastrointestinal bleeding and ulceration. Increased risk of myocardial infarction and stroke.
Celecoxib	Patients with indications for cardio protection require aspirin supplementation 200 mg once daily or 100 mg q 12 h
Meloxicam	Long duration of effect 7.5–15 mg once daily

CNS , Central nervous system; COX , cyclooxygenase enzyme.

Serious GI side effects, such as peptic ulcer bleeding and perforation, have been reported in 2% to 4% of chronic NSAID users. Of importance, this risk may be decreased by half with the use of a selective cyclooxygenase-2 inhibitor (such as celecoxib). COX-2 selective inhibitors were developed to inhibit prostaglandin synthesis at sites of inflammation without disrupting the homeostatic function of the COX-1 enzyme on GI mucosa, the kidney, and platelets. Therefore, the selective COX-2 inhibitors have analgesic and antiinflammatory effects equivalent to the traditional NSAIDs with 50% to 60% less GI adverse effects and no effect on platelet function. However, orthopaedic surgeons must be aware that COX-2 inhibitors have been found to significantly increase the risk of myocardial infarction and stroke in patients with preexisting cardiac, renal, and vascular disease.

Nonoperative Treatment Modalities: Moderate Recommendation

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here