surgical concepts are challenging this approach to device selection, and there is emerging research suggesting that partial resurfacing options including unicondylar, bi-unicompartmental, or PF arthroplasty may be an option, especially in younger patients, to preserve bone stock and proprioceptive input from the cruciate ligaments (Borusa, Brilhaultb, Confalonieric, Johnsond, & Thienponte, 2014). In a recent study by Benazzo et al., they report on 55 patients treated with PF arthroplasty with a mean follow up of 56+ months and report good to excellent outcomes as measured on the Hospital for Special Surgery (HSS) score, the Knee Society’s Knee Scoring System (KSS), and the Oxford Knee Score (OKS; Benazzo, Rossi, & Ghiara, 2014). Aside from the task of deciding on the type of knee replacement, it is also possible that two painful knees may need replacing at once. In these situations, the surgeon and patient must decide whether to replace one knee and then the other in a staged approach, either within days or months of each other, or to replace both knees simultaneously. Generally, complications and in-hospital mortality rates are greater for patients undergoing simultaneous bilateral knee replacements than those having one knee operated on (Fu et al., 2013; Yoon, Han, & Yang, 2010); however, the changing demographics of patients that are undergoing these procedures complicates the research, because they tend to be younger and have fewer comorbidities at baseline. When bilateral TKA is approached in a staged fashion, there seems to be no consensus on the optimal timing. A consensus statement by national experts in orthopedic surgery anesthesiology, perioperative medicine, and epidemiology states the optimal hiatus between staged TKA should be at least 3 months; however, there is very little data to support the appropriate timing between surgical procedures (Memtsoudis et al., 2013). remain equivalent. Future research in this area should also take into consideration the duration of treatment, which may be important when interventions such as muscle strengthening are used. Prehabilitation seems to be effective in helping patients who are obese optimize their recovery from TKA. In a larger study of more than 200 patients with BMI > 30kg/m 2 , only 6.8% of those who had exercised before surgery needed the help of two or more caregivers on the first postoperative day, as compared with 17.4% of obese controls (Robbins et al., 2010). In the same study, a larger percentage of patients who had participated in prehabilitation activities were able to be discharged directly home rather than to an inpatient rehabilitation facility (Robbins et al., 2010). Aquatic therapy may be a useful means of exercising in a reduced body weight environment for both obese and normal weight patients, and it is thought to help with painful symptoms of knee arthritis. However, in a large review of the literature, only one study was identified that examined the effect of aquatic therapy specifically on patients with knee OA. The results did demonstrate a positive short-term effect in which there was significantly decreased pain immediately after treatment, but there was no commensurate improvement in walking ability or knee stiffness (Bartels et al., 2007). In a more recent study of obese patients (BMI > 25 kg/m 2 ) participating in an aquatic therapy program (three times a week over a period of 8 weeks) that was designed to improve knee function and promote weight loss, there was an improvement in both pain level and body fat composition for the aquatic therapy group as compared with controls, but actual weight loss was not statistically significant (Lim, Tchai, & Jang, 2010). More research on this topic is clearly needed. Quadriceps strengthening is a specific component of prehabilitation that is particularly important, because quadriceps weakness appears to be correlated with worse symptoms of knee OA (Segal et al., 2009). Weakness typically worsens following
Table 2: Comparison of Prosthesis Survival Rates in Unicondylar Versus Total Knee Arthroplasty Type of Surgery
5 Years 10 Years 15 Years 89.4%-95% 80.6%-90% 69.9%
Unicondylar
Total knee arthroplasty
96.3%-98% 93.3%-95% 88.7%
Note. Adapted from Lyons, MacDonald, Somerville, Naudie, & McCalden, 2012; Niinimaki, Eskelinen, Makela, Ohtonen, Puhto, & Remes, 2014. The most common reasons for failure in unicompartmental arthroplasty are aseptic loosening and progression of OA (van der List, Zuiderbaan, & Pearle, 2016). Patients with BMI > 35 kg/m 2 who have medial compartment OA must proceed with caution when considering a unicondylar knee replacement because they are at increased risk for rapid revision to TKA within a 2-year period (Bonutti et al., 2011). Unicondylar knee replacements account for fewer than 8% of all knee arthroplasties being performed in the United States, but they are being increasingly done as the need for arthroplasty surgery is rising in younger patients who wish to delay or avoid a full TKA (Riddle, Jiranek, & McGlynn, 2008). Symptoms of knee pain that affect the patellofemoral joint (anterior compartment) can influence the decision to proceed with a TKA instead of a unicondylar knee arthroplasty to minimize the need for early revision for ongoing PF symptoms (Yue, Zhang, & Yang, 2015). Historically, unicondylar arthroplasty was primarily offered only to patients with either medial or lateral compartment disease and evidence of PF arthritis was considered a contraindication for unicondylar implants. Recent Preoperative rehabilitation Patients who are not yet ready for surgery, those who are on a surgical waiting list, and patients in the process of losing weight prior to TKA may benefit from physical therapy intervention to address impairments and functional limitations. Preoperative rehabilitation, or “prehabilitation,” consisting of flexibility and strengthening exercises improves pain and functional performance both before and after TKA in case studies (Brown et al., 2010; Jaggers et al., 2007). However, a systematic review and meta-analysis by Gill et al. found no significant difference in pain, functional ability, walking speed, or strength in patients who exercised prior to surgery compared to those who did not exercise (Gill & McBurney, 2013). One could argue that the pain associated with end-stage arthritis may impede the patient’s ability to fully participate in effective exercises, which may explain these results. Additionally, it has been shown that higher preoperative levels of function are predictors of successful outcomes following TKA (Judge et al., 2012; Kahn, Soheili, & Ran Schwarzkopf, 2013); however, intervention studies examining the effect of prehabilitation have not demonstrated positive effects on patient outcomes after surgery (Baker & McKeon, 2012). Some of the challenges measuring the effectiveness of prehabilitation are related to the outcome measures and the timing of baseline and follow-up assessments. Outcomes such as the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), ROM, strength, and length of stay (LOS), have been used to evaluate prehabilitation programs. Although these are valid and reliable outcome measures, they do not capture functional performance, which is highly correlated with physical impairments such as muscle weakness. This is an important consideration, as self-reported outcomes and performance- based measures capture different domains of recovery; the former is driven by joint pain, whereas the latter is related to muscle strength and endurance (Mizner et al., 2011; Stevens- Lapsley, Schenkman, & Dayton, 2011). In addition, it may be useful to capture the impact of a rehabilitation program earlier in the recovery phase after TKA. Prehabilitation may have an impact on the rate of recovery, even if longer-term outcomes
Book Code: PTNY3622B
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