of a tourniquet, the overall incidence of postoperative DVT was 81.3% as detected by ultrasonography, and symptomatic PE was 1.7%; the incidence of DVT was the same in both groups, although the nontourniquet group sustained significant blood loss during surgery (Fukuda et al., 2007). A recent meta-analysis by Tie et al. reinforces the findings that tourniquet time does not increase the incidence of DVT (Tie, Hu, Qi, Wang, & Chen, 2016). The greatest risk factors for the development of venous thromboembolism (VTE) after TKA are a prior history of VTE, the presence of varicose veins, and congestive heart failure (Zhang, Chen, Zheng, Breusch, & Tian, 2015). Prophylaxis for DVT and PE is given according to an individual patient’s risk for major bleeding and PE according to their medical history and preoperative testing, and it may consist of mechanical prophylaxis (pneumatic compression boots) and aspirin, or other anticoagulation medications after surgery (Sheth, Lieberman, & Della Valle, 2010). Antiembolism stockings may also be used. The risks of postoperative DVT and PE can be mitigated by appropriate pharmacological and mechanical prophylaxis, but also may be reduced through the type of anesthesia chosen. Twenty-one studies recently examined in a meta-analysis showed that the incidence of DVT and PE is lower when using regional anesthesia instead of general anesthesia (Hu, Zhang, Hua, Li, & Cai, 2009). Given the serious consequences of DVT and the fact that they are not always identified prior to discharge from the hospital setting, it is important for the physical therapist to be aware of signs indicating DVT. Increased pain, swelling, temperature, and redness in the leg may occur with a DVT, but these clinical signs are poor indicators of the presences of a DVT. Homans’ sign should not be relied upon for clinical diagnosis as it is neither sensitive nor specific for the presence of DVT (Bounameaux, Perrier, & Righini, 2010). A clinical prediction rule, developed by Wells, has been validated for assessing the probability of DVT. This rule can be easily implemented by the therapist, with a total score of 1 to 2 indicating moderate and a score greater than 2 indicating high probability of the presence of DVT (Wells et al., 1995; Wells, 2006). Scoring is based on clinical characteristics of the patient, including the presence of an active cancer comorbidity, lower extremity immobilization, bedrest longer than 3 days, recent surgery, and clinical examination findings of tenderness in the deep vein distribution, lower extremity swelling, unilateral pitting edema, collateral superficial veins, and a history of DVT. An online resource to score a patient with this tool can be found at http://www.mdcalc.com/wells-criteria-for- dvt Infection With any surgical procedure infection is always a risk, but with TKA the overall infection rate is approximately 1% (Zhu et al., 2015). Factors that increase that risk are prolonged operating time, increased tourniquet length of time, and male gender (Willis-Owen, Konyves, & Martin, 2010). Patient-related factors that amplify the risk of infection include increased BMI, wound issues, corticosteroid use, low serum albumen levels, and diabetes (Jämsen, Nevalainen, Kalliovalkama, & Moilanen, 2010; Samson et al., 2010; Zhu et al., 2015). While the risk is low, deep infection can be a devastating complication, requiring surgical debridement and long-term intravenous antibiotics. Administration of prophylactic antibiotics can reduce the relative risk of infection with TKA surgery by 81% (AlBuhairan, Hind, & Hutchinson, 2008). At the time of the surgery, antibiotics can be given intravenously, and antibiotics can also be impregnated into the bone cement used during the operation. The timing of antibiotic administration is important during the preoperative period. Delivery of intravenous antibiotics 30 minutes before the initial incision of the skin is considered
optimal to ensure adequate tissue perfusion of the antibiotics. When antibiotics are given 60 minutes prior to surgery, the risk of infection actually increases, possibly due to the short half-life of commonly used antibiotics (Stefánsdóttir et al., 2009). Early signs of infection in the area of the incision include increased temperature, edema, redness, and sometimes drainage from the incisional area. The patient may or may not have cardinal signs of systemic infection, such as fever, rigors, and overall malaise. Prompt referral to the surgeon is paramount because early management of infection is critical for a successful outcome. Stiffness Limited ROM postoperatively, often described as stiffness, is a relatively infrequent complication of TKA, but is one of the most common reasons for surgical non-revision reoperation. Stiffness leading to manipulation under anesthesia (MUA) has been reported in 1.3% to 13.5% of TKA cases performed (Rubinstein & DeHaan, 2010; Zmistowski, Restrepo, Kahl, Parvizi, & Sharkey, 2011). Risk factors for painful limitation in ROM following TKA include preoperative stiffness, diabetes, and previous knee surgeries. They also include postoperative infections, arthrofibrosis (excessive scar tissue formation or adhesions), heterotrophic ossification, and insufficient postoperative rehabilitation (Schiavone Panni, Cerciello, Vasso, & Tartarone, 2009). After TKA, patients with a higher body mass index (BMI 30 kg/m 2 and above) are nearly twice as likely to need MUA for their stiff knees compared with thinner patients (Gadinsky, Ehrhardt, Urband, & Westrich, 2011). Closed MUA is most effective when performed within 8 weeks of the TKA surgery, and it results in a gain of 4º of extension and 22º of flexion, on average (Cates & Schmidt, 2009). No matter the cause, postoperative knee stiffness is challenging from a rehabilitation perspective for both the patient and the therapist. Instability Knee instability following TKA is fortunately a rare occurrence that happens in less than 1% of cases (Carothers, Kim, Dennis, & Southworth, 2010). Increased ligamentous laxity that may be caused by poor soft-tissue balancing at the time of the surgery can result in a knee that feels unstable to the patient and that may cause a shifting sensation during gait. However, it is likely that any residual ligamentous laxity that may have occurred at the time of surgery in response to bony realignment will resolve with time. A Japanese study showed that after correcting for a varus deformity, knees with residual LCL laxity of as much as 8.6º on the day of surgery spontaneously decreased to nearly 5º by the third postoperative month (Sekiya, Takatoku, Takada, Sasanuma, & Sugimoto, 2009). Instability is also common at the PF joint following TKA, and can result in anterior knee pain and patellar tendinosis due to abnormal forces on the soft tissues. Female patients are especially at risk for poor PF tracking after TKA due to the increased tendency toward a valgus deformity in the female knee, as are patients with patellae that are significantly malformed by arthritis preoperatively (Anglin et al., 2009). Studies suggest that the best approach to solving this problem is the use of more careful computer-assisted measurement of patellar kinematics as opposed to freehand bone cutting while the patient is still on the operating table (Anglin et al., 2008; Mihalko, Sherrell, Saleh, & Whiteside, 2009). In some cases, a release of tight lateral structures may be necessary to restore soft-tissue balance, either during the original TKA or at a later date (Aglietti, Lup, Cuomo, Baldini, & De Luca, 2007). Studies exploring the efficacy of using PF taping to treat the mal-tracking of the patella after TKA have not been performed, however approaching this issue from a rehabilitation perspective of PF dysfunction and the role of the entire kinetic chain to address PF function may be most effective.
POSTOPERATIVE REHABILITATION
Successful outcomes following TKA require ongoing rehabilitation to maximize the functional ability of the patient. Typically patients will receive physical therapy in the acute
care setting either on the day of surgery or the following day, and will continue with their rehabilitation in the post-acute setting either at home, in an outpatient office setting, or an
Book Code: PTNY3622B
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