the rigors of TKA surgery and recovery, so it can be difficult for patients to regain full strength in the operated leg. If quadriceps strength does eventually return to preoperative levels, it can take more than 2 years to do so, and even then quadriceps muscle strength of the operated leg may never attain the same level of strength as the non-operated leg (Saleh et al., 2010). However, prehabilitation that includes progressive resistive exercises and neuromuscular electrical stimulation can improve quadriceps muscle activation and strength before TKA and enhance functional postsurgical outcomes (Saleh et al., 2010; Walls, McHugh, O’Gorman, Moyna, & O’Byrne, 2010). Although these findings are promising, studies on this topic so far have been small and in some cases methodologically flawed. More research is needed to fully support the use of neuromuscular electrical stimulation as a means to increasing quadriceps strength before TKA (Monaghan, Caulfield, & O’Mathúna, 2010).
An important part of prehabilitation is patient education, to enable patients to understand what to expect during their recovery after TKA surgery. Not only does better understanding offset preoperative fears, but it can also reduce the hospital stay itself by as much as a full day (Yoon, Nellans, et al., 2010). Patients who experience preoperative patient education in the form of a single interdisciplinary class session demonstrate superior comprehension and performance of the necessary postoperative skills, and they have a better understanding of what to expect after surgery (Thomas & Sethares, 2008). Although physical therapists are often the health professionals who spend the most time with the patient postoperatively and are the ones to provide the bulk of patient education, there have been no studies that examine the positive effects of the patient- therapist interaction either preoperatively or postoperatively. Further research on physical therapy patient education before TKA is needed with appropriate metrics to examine the effect on the recovery process and not just the outcome of TKA. seem to facilitate faster short-term recovery of ROM, especially during the first 6 days after surgery, but ROM and knee scores are no different than more conventional approaches 6 months after surgery. In addition, the minimally invasive approach has a greater risk of infection and delayed wound healing as reported by Cheng et al. in a systematic review of 13 studies (Cheng et al., 2010). Two recent meta-analyses reveal no significant difference between the minimally invasive and conventional surgical approaches, radiologically, clinically, or in complication rates (Gandhi, Smith, Lefaivre, Davey, & Mahomed, 2011; Smith et al., 2012). Surprisingly, the authors of one literature review concluded that the traditional surgical approach resulted in decreased patient pain perception than the minimally invasive approach to TKA (Moretti et al., 2010). Further research is needed to clearly illustrate the benefits of minimally invasive TKA procedures. The definitive components are cemented into place with polymethylmethacrylate cement, although some surgeons may use cementless press-fit implants in younger patients. Whether cement is used usually does not impact the postoperative recovery or impose different weight-bearing precautions. Throughout the procedure, careful attention is given to protecting the patellar tendon from being tensioned to avoid its avulsion from the tibial tubercle. Finally, if the PF joint has significant degenerative changes, the patella is resurfaced and inspected for correct tracking without subluxation prior to closure (Heislein & Eisemon, 2016). Computer navigated or assisted surgery may be used to improve implant position relative to the mechanical alignment of the lower extremity. The computer system determines the femoral and tibial bone cuts based on markers placed on the lower extremity. Currently there is no consensus on whether this improves patient outcomes; however, long-term follow-up studies are needed to evaluate the impact of computer assisted surgery (Cheng, Zhao, Peng, & Zhan, 2012). Deep vein thrombosis Lower extremity joint reconstruction surgery is associated with a high rate of blood clots, but fortunately with TKAs, most clots are small and form in the distal calf area, rather than in the thigh region where they are associated with pulmonary embolism (DeHart, 2009). However, it is estimated that without prophylaxis, the rate of DVT with TKA ranges from 41% to 85%, and pulmonary embolism (PE) can occur in 1.5% to 10% of surgeries (DeHart, 2009). Tourniquets are routinely used to prevent blood loss during TKA, but some investigators worry that tourniquet use can promote blood clot formation. In a study of 48 patients undergoing TKA with and without benefit
SURGERY
Once decisions have been made about the type and timing of TKA to be performed, the patient has completed all of their preoperative medical work-up, and has prepared their home environment for the postoperative recovery period, the patient can proceed with surgery. There has been a movement toward minimally invasive TKA utilizing a smaller incision and quadriceps- sparing approach. This approach creates an incision through the vastus medialis oblique muscle versus along the quadriceps tendon, allowing the patella to be subluxed laterally rather than everted, to minimize dysfunction of the extensor mechanism. Although proponents describe accelerated recovery times with greater quadriceps strength and improved ROM, opponents cite a higher incidence of peroneal nerve injury and need for revision surgery (Cheng, Liu, Zhang, Peng, & Zhang, 2010; Smith, King, & Hing, 2012). The minimally invasive approach does Overview of the surgical procedure Surgical approaches differ according to surgeon preference, but a medial parapatellar incision is the most commonly used. If previous scars are present, the surgeon may attempt to incorporate the old scar with the new one. With respect to knee ligaments, the ACL is sacrificed, the PCL may be retained or substituted depending on the level of ligamentous degeneration, and the MCL and LCL are preserved (Crockarell & Guyton, 2013). During surgery, the medial and lateral menisci are removed, along with osteophytes that may be protruding into the surrounding ligaments. Bone cuts are made using an intramedullary alignment system and are measured precisely to ensure the implant will recreate the correct level of the joint line for proper balance of the soft tissues and positioning of the patella (Heislein & Eisemon, 2016). Knee ROM is tested once the implants are positioned to ensure there is correct tension on the retained ligaments to avoid undesirable laxity and postoperative instability. Joint contractures are released, joint deformities (varus or valgus deformities) are corrected, and sometimes a lateral release is performed when a severe valgus deformity was present prior to surgery, all to balance the soft tissues, attain the correct implant alignment, and allow optimum load sharing through the prosthesis. Common complications As with any major surgery, complications may occur despite the most careful setup. The most common complications associated with TKA include deep vein thrombosis (DVT), infection, arthrofibrosis, and knee instability. Physical therapists have close interactions with patients on a regular basis after surgery and should always assess the patient for the potential development of DVT or infection. Fortunately, TKA is a fairly safe procedure that is associated with a 20-day postoperative mortality rate of 0.2% and a mortality rate of only 1.6% at the 1-year postoperative mark, which is approximately half of that occurring in the general age-matched population (Williams et al., 2010).
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Book Code: PTNY3622B
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