developing realistic expectations and the time frames to achieve them will enhance the overall rehabilitation process and may influence outcomes. While more than 90% of patients report being satisfied with their surgical outcomes in terms of pain relief, and 80% are satisfied with the improvement in their functional mobility by 5-years post- surgery (Singh & Lewallen, 2014), there are reports of unfulfilled expectations following TKA surgery. Tasks such as kneeling down and squatting are often not achieved 1 year after surgery (Tilbury et al., 2016), stair climbing may still require handrail assistance (Zeni & Snyder-Mackler, 2010), and participation rates in leisure activities such as golfing and dancing are less than patients’ expectations (Nilsdotter, Toksvig-Larsen, & Roos, 2009). Postoperative satisfaction is strongly associated with expectations from surgery, and unmet expectations result in dissatisfaction (Choi & Ra, 2016). Patients with lower WOMAC scores and greater preoperative pain and disability were more likely to be satisfied after TKA, but those with lower preoperative health- related quality of life measures tended to be less satisfied after knee replacement surgery (Maratt, Lee, Lyman, & Westrich, 2015). While most studies evaluate impairment-level and functional- level outcomes, one study specifically examined participation restrictions in patients after TKA. Overall, patients demonstrated improvement in pain and function yet 30% had participation restrictions at 1+ year post surgery. These participation restrictions were more common in women, racial minorities, those with depressive symptoms, severe pain in either knee, and lower pre- TKR functional status (Maxwell et al., 2013). These findings reveal the complexity in evaluating patient participation following TKA, and the resolution of pain and improved function are not the only factors that limit social participation. Not only do the actual goals need to be feasible, but patients also need to understand realistic time frames to achieve their goals. Patients may be overly optimistic in their goals, and they may underestimate the time needed for full recovery, consequently, therapists and surgeons alike must help patients understand the parameters of the surgery and recovery at the outset and counsel appropriately. The first 12 postoperative weeks are the most critical for recovery, because this is the time frame when the greatest improvements are made (Kennedy, Stratford, Riddle, Hanna, & Gollish, 2008). The rate of improvement slows down between the 12th and 26th week, with minimal improvement noted on the 6-minute walk test (6MWT) and Lower Extremity Functional Scale (Kennedy et al., 2008). Functional status appears to be more closely linked to pain scores and patient-reported function than ROM, or even to objective functional measures after surgery (Jacobs & Christensen, 2009). However, it is important to periodically measure knee ROM after TKA, as the gains in ROM may be objectively recorded and tracked, which can be a motivating factor for patients to stay compliant with their rehabilitation. True knee stiffness is defined as flexion less than 75º and extension worse than –15º, and despite such ROM theoretically being adequate for gait, most patients report clinically debilitating stiffness at much greater ranges of motion (Su, Su, & Della Valle, 2010). With a goal of being able to move from sit to stand with ease, knee flexion must be at least 93º for adequate function (Crockarell & Guyton, 2013). On the other end of the ROM spectrum, knee flexion contractures that result in poor end-range extension may also be a problem when greater than 10º. Preoperative ROM is the best predictor of postoperative ROM, so patients with significant preoperative ROM deficits need increased attention to edema management and ROM exercises to maximize joint mobility before arthrofibrosis develops. Predictors of outcomes have been examined to help determine who will benefit the most from TKA, but can also provide insight
into areas that should have enhanced focus during rehabilitation to maximize outcomes. The strongest predictors of pain relief and functional outcomes following knee arthroplasty surgery include preoperative pain, function, and WOMAC scores (Judge et al., 2012; Kahn et al., 2013). Factors that contribute to worse outcomes of continued pain and disability after TKA include poor preoperative functional status (Judge et al., 2012), preoperative pain levels (Lewis, Rice, McNair, & Kluger, 2015), a large number of comorbidities (da Silva et al., 2014; Elmallah, Cherian, Robinson, Harwin, & Mont, 2015), low socioeconomic status, older age (da Silva et al., 2014), and female gender (Mehta, Perruccio, Palaganas, Davis, 2015; O’Connor, 2011). In addition, maladaptive cognitive and behavioral strategies such as kinesiophobia and catastrophizing, as well as mental health issues such as depression have been shown to be predictors of poor outcomes regarding function, ROM, chronic pain, satisfaction, and quality of life after TKA (Brown et al., 2016; Burns et al., 2015; Doury-Panchout, Metevier, & Fouquet, 2015; Khatib, Madan, Naylor, & Harris, 2015; Lewis et al., 2015; Vissers et al., 2012). These findings suggest that a comprehensive biopsychosocial approach to patient care and mental health interventions may be indicated for some patients to improve their outcomes. Further research in this area is needed. Despite intensive rehabilitation protocols designed to advance flexibility, strength, and functional movements, many patients continue to have functional deficits after the surgery. When measuring functional performance via the TUG test, 6MWT, stair- climbing test, and single-limb stance time, patients with TKA all performed below their baseline preoperative levels 1 month after surgery, and by 6 months, the patients had regained their preoperative functional levels but were still below the functional levels of healthy controls (Bade, Kohrt, & Stevens-Lapsley, 2010). Their continued level of functional impairment suggests that a typical rehabilitation program may not be enough to restore full leg function after TKA, because the level of resistance with strengthening exercises is often suboptimal and the duration of treatment is not adequate to fully restore strength (Bade et al., 2010). When measuring postsurgical improvement via the sit-to- stand task, TKA patients may show nearly normal ability to load the operated leg by 6 months, but remain unable to generate the same knee extension velocity during rising as controls (Boonstra, Schwering, De Waal Malefijt, & Verdonschot, 2010). Further research focused on strength recovery shows some early positive results that NMES, when utilized early in recovery, may ameliorate quadriceps activation failure and lead to increased strength later in recovery (Kittelson, Stackhouse, & Stevens- Lapsley, 2013; Stevens-Lapsley, Balter, Wolfe, Eckhoff, & Kohrt, 2012). These protocols require a more aggressive approach to increased resistance/load with strengthening to maximize improvements. As recovery takes place following TKA, and the operated limb becomes stronger and more stable, the non-operated limb may negatively affect functional mobility, especially if the patient has bilateral knee OA. In a study examining 2,917 patients who received a TKA, 46% required a TKA on the contralateral side approximately 3 years after their initial surgery, as pain and weakness in the non-operated leg impaired functional performance (Shao et al., 2013). Returning to work is a newer outcome that has been reported following TKA as younger patients are pursuing this surgery to address limitations in function. Patients may also be choosing to have these procedures while still employed for insurance coverage reasons. A recent systematic review reports 71% to 83% of patients returned to work within 3 to 6 months after knee replacement surgery (Tilbury et al., 2014).
FUTURE CONSIDERATIONS
Consistent use of standardized outcome measures in the rehabilitation of patients undergoing TKA should be a regular component of physical therapy practice. As reimbursement
models evolve, including the latest Medicare Bundled Payments for Care Improvement Initiative, the need to identify and utilize the most appropriate outcome tools will be required for physical
Book Code: PTNY3622B
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