Patient selection Total knee arthroplasty is typically indicated for patients who have exhausted conservative treatments for persistent knee pain and have radiographic evidence of structural changes in the joint that are consistent with end-stage knee OA. Because two main goals of TKA are to alleviate pain and improve functional mobility, surgical candidates will typically demonstrate persistent, moderate to severe levels of knee pain, significant joint damage as seen on x-ray, and poor functional mobility that is adversely affecting their quality of life (Van Manen, Nace, & Mont, 2012). Factors that may be considered in the decision to proceed with TKA include symptoms, age, sex, and race. Although TKA is one of the most successful elective surgeries performed in the United States, the criteria for when to refer patients for surgery varies depending on the surgeon. Across the board, pain that remains unresponsive to medication is the consistent element that drives the decision whether to undergo surgery (Verra et al., 2016). The top reason physicians recommend TKA for patients is pain that occurs with weight- bearing activities and that remains at rest or occurs during the night; however, most surgeons also take functional limitations into consideration in addition to the severity of radiographic changes (Nguyen, Ayers, Li, Harrold, & Franklin, 2016; Verra et al., 2016). Symptom severity is assessed not only by medication use and whether sleep is disturbed by pain, but also by the ability to walk without an assistive device and whether patients are able to navigate curbs, stairs, and inclines (Williams et al., 2010). Previously, older patients (> 85 years) were less likely to be offered TKA to manage knee pain from OA; however, a recent systematic review and meta-analysis of 22 studies demonstrated only a small increase in mortality, myocardial infarction, deep vein thrombosis, and length of stay compared to younger patients. Older patients did not have a greater risk of pulmonary embolism and these patients had similar rates of improvement following TKA, suggesting that advanced age should not be a limiting factor in considering TKA in medically appropriate patients (Kuperman, Schweizer, Joy, Gu, & Fang, 2016). On the other end of the age spectrum, TKA previously was only considered for patients over age 65 years because there was concern that younger patients would outlive the implant and require revision. Younger patients are seeking knee replacements as a means to maintain an active lifestyle and a recent study by Losina and colleagues demonstrated that the increased demand for TKA in the United States is not just a function of the aging Associated diagnoses/precursors to surgery The most common diagnosis leading to TKA is joint failure caused by severe OA (Van Manen et al., 2012). Other diagnoses include RA, post-traumatic arthritis, osteonecrosis, pseudogout, and severe patellofemoral arthritis (Williams et al., 2010). While it is difficult to rate the individual risk factors of each form of arthritis that may lead to an individual eventually needing a TKA, a recent Australian study tried to assess whether weight- bearing exercise in the presence of OA might hasten the need for a joint replacement. In a prospective cohort study of more than 41,000 people, vigorous physical activity was linked to an increased risk for subsequent knee replacement (Wang et al., 2011); however, these results are based on self-reported levels of activity at the start of the study with no additional examination of physical activity throughout the study. Less vigorous exercise, such as walking, was not associated with an increased risk of knee replacement. A recent systematic review of physical activity in older persons with knee pain did not demonstrate a negative effect of low-level exercise on the progression of knee pathology (Quicke, Foster, Thomas, & Holden, 2015). It may be best to encourage participation in activities that promote strength, but do not overload the knee. In a large study of 3,856 knees, quadriceps weakness was associated with worsening of the knee joint space over a 30-month period in women, but not in men (Segal et al., 2010), and quadriceps strengthening has not been
population and obesity epidemic, but a shift to include younger patients due to the growing number of knee injuries sustained earlier in life and the expanding indications for TKA (Losina, Thornhill, Rome, Wright, & Katz, 2012). Gender has also been examined as a factor that impacts who is offered TKA. A small Canadian study revealed that a group of 71 family medicine and orthopedic surgeons who performed blinded assessments of two standardized patients, one male and one female, were four times more likely to recommend TKA surgery to the male patient (as opposed to the female one) based on identical scenarios of functional mobility, reported pain, sleep disturbance, and use of pain medications (Borkoff et al., 2008). In the same study, more than 90% of orthopedic surgeons, but only 60% of family medicine physicians considered at least one of the standardized patients to be an appropriate candidate for TKA. In general women tend to wait longer to seek or be offered TKA and have lower preoperative functional scores compared to men (Mota, Tarricone, Ciani, Bridges, & Drummond, 2012; Parsley et al., 2010). More recent studies report that while the overall rate of TKA is lower in non-white patients (Collins et al., 2015; Shahid & Singh, 2016), patient race and sex do not appear to influence the decision to recommend TKA when there is strong clinical data (pain, limited function, and radiographic changes) to support the decision to proceed with surgery (Dy et al., 2015; Gooberman-Hill et al., 2010). The racial disparities are primarily associated with socioeconomic factors and patient expectations about the surgical procedure and likely outcomes (Mota et al., 2012). Despite the improvement that many patients achieve with TKA, not all patients considered appropriate for TKA will choose to proceed with the surgery. In a 2010 study of 120 patients with end-stage knee OA, only 33% underwent TKA surgery within 2 years following functional and clinical assessment (Zeni, Axe, & Snyder-Mackler, 2010). In the study, functional limitations were measured by using clinical tests such as the Timed Up and Go (TUG) test and Stair Climb Test (SCT), and patients rated their perceived functional abilities using the ADL subscale of the Knee Outcome Survey (KOS-ADLS). Clinically, patients were also measured for knee AROM, quadriceps strength, height, and weight. The study found that increasing age, weakness, and functional impairment, and decreasing end-range knee extension, were the main predictors for surgery (Zeni et al., 2010). shown to contribute to the progression of knee OA (Segal & Glass, 2011). Factors thought to lead to early OA and subsequent TKA include ACL laxity or deficiency and meniscal injury, which may lead to joint instability and traumatic arthritis. Generally, patients needing a TKA are likely to have had previous surgery or trauma to the knee joint, including both meniscal and ACL injuries (Forriol et al., 2010). Another study that followed 19 East German Olympic athletes from the 1960s who had sustained an ACL injury found that within 10 years, 79% underwent a meniscectomy, and by the 20th year, meniscectomy was necessary in all but one of the athletes; nearly half of all the athletes (mean age of 59) progressed to TKA by the 35th year (Nebelung & Wuschech, 2005). This is significantly higher than the 4.6% prevalence of TKA among adults age 50 and older reported by the AAOS (AAOS, 2014). A recent meta- analysis of 644 ACL-injured knees found a five times increased risk of developing radiographic knee OA within 10 years of injury, regardless of reconstructive surgery or nonoperative management. Confounding variables in this research include a lack of control for secondary meniscal injuries and the rate of return to sports versus modification of activity levels (Ajuied et al., 2014).
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Book Code: PTNY3622B
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