resurfacing option to conserve bone and offset the need for multiple revision THAs in their lifetime because a resurfaced hip is easier to revise than a replaced one (Sershon, Balkissoon, & Valle, 2016). With hip resurfacing, the damaged femoral head is not removed and replaced but instead is reshaped and capped with a metal covering which is cemented in place. The damaged acetabulum is fitted with a metal prosthetic socket, similar to THA. This is in essence then a MoM relationship as described above. The use of metal components lends itself to the same concerns with the MoM THA surgical procedure with ion release. Patient selection for hip resurfacing is important, as is component selection. Surgical approaches There are many different surgical approaches for a THA depending on a patient’s anatomy and an orthopedic surgeon’s preference (Chen et al., 2013). The most common approaches for THA are posterior, lateral, and anterior. Posterior/posterolateral The posterior or posterolateral approach is the most commonly used approach in the United States. During this procedure the hip abductor muscles are not exposed to an incision, which is thought to reduce the incidence of Trendelenburg gait. The only muscles that are incised and reflected during the procedure are the hip external rotators, along with the posterior capsule. Due to the anatomical location of these muscles in supporting the posterior aspect of the femoral head, their detachment and subsequent reattachment results in the posterior stabilizers of the hip being compromised until soft-tissue healing can occur. This therefore is the reason for the use of hip posterior precautions following THA when this surgical approach is used. Benefits to the surgeon in using this approach are greater visibility of the hip and reduced insult to the hip abductor muscles. However the risk of postsurgical hip dislocation increases with this approach, in particular when a patient cannot comply with the hip posterior precautions (Chen et al., 2013). Lateral The lateral approach involves a partial release of the abductor muscles from the femur in order to access the hip joint during the THA. At the end of the surgical procedure these muscles are reattached, but the element of detachment and or use of the surgical retractors can lead to reduced activation of these muscles immediately following surgery and a subsequent Trendelenberg gait. A benefit of this surgical approach is reduced likelihood of hip dislocation while still allowing for good visibility of the joint during the surgical procedure (Chen et al., 2013). Complications Risk is associated with any surgical procedure, and THA is no exception. The most concerning complication is the risk of perioperative death; however, the overall mortality rate for elective THA is fortunately very low, less than 0.40%, and the risk of complications following THA is 4.9%. Those aged over 70 and who had renal insufficiency best predicted mortality and those aged over 80 and who had cardiac disease best predicted those who had postoperative complications. Patients who were morbidly obese and who had operative times that extended beyond 141 minutes had the greatest risk of major local complications (Belmont et al., 2014). The most common complications following THA are deep vein thrombosis (DVT), postsurgical infection, and hip dislocation. Additional complications include aseptic loosening, femoral neck fracture, and component or hardware impingements (T. D. Brown, Elkins, Pedersen, & Callaghan, 2014). Deep vein thrombosis Deep vein thrombosis (DVT), also known as venous thromboembolism, can occur after any surgery but is more likely following surgery involving the hip, pelvis, or knee. Blood in the large veins of the lower limbs forms clots, which causes the limb to swell and become tender; however, DVT may also be
It is imperative that the surgeon choose the correct size of femoral cap to fit the patient’s native femoral head without overly stressing the underlying bone and creating torque on the femoral neck. Therefore, the actual size of the femoral neck is also considered during the process of patient selection (Pailhe et al., 2012). Several factors affecting long-term success are component size, implant design, preoperative diagnosis, patient sex, and surgical technique. Additionally there have been increased concerns with metal ion levels and adverse local tissue reaction (Pailhe et al., 2012). Therefore at this time controversy remains surrounding the appropriateness of this surgical approach. Anterior The anterior approach is being performed more frequently in an effort to mitigate the risk of postoperative dislocation associated with the posterior surgical approach and the challenges of Trendelenburg gait associated with the lateral surgical approach (Post, Orozco, Diaz-Ledezma, Hozack, & Ong, 2014). It has become easier to perform a THA using this anterior approach due to the development of new surgical equipment and operating tables. Using this approach, muscle does not need to be cut to gain access to the hip joint and the incision goes through the interval between muscles just lateral to the anterior superior iliac spine (ASIS; (Chen et al., 2013). Minimally invasive approach Several of the surgical approaches have moved to using a mini- incision, in which a shorter than traditional length of incision is made. Specialized surgical equipment is used to perform the surgery through this smaller access site. In the case of this variation of surgical approach one or two small incisions are made to spare the underlying soft tissues from surgical trauma. Candidates for this type of approach are of thinner build and are younger, healthier, and more active than those requiring a traditional longer incision. The incisions are usually 3 to 6 inches long and may require X-ray (fluoroscopy) or computer-assisted guidance and special surgical instruments to maneuver the prosthesis into place. Benefits of minimally invasive surgery (MIS) include less soft-tissue damage and postoperative pain, reduced blood loss, and a shorter hospital stay (Zawadsky, Paulus, Murray, & Johansen, 2014). An added benefit of computer-assisted surgery is increased surgical precision with implant positioning that results in a decreased incidence of potential postsurgical leg length discrepancies (Nakamura, Sugano, Nishii, Kakimoto, & Miki, 2010). asymptomatic. When a blood clot detaches, it can travel to the lungs and lodge in pulmonary capillaries, creating a potentially fatal pulmonary embolism. Current guidelines recommend the use of thromboprophylaxis in patients undergoing THA with the most commonly used anticoagulants being low-molecular- weight heparin, fondaparinux, and adjusted-dose warfarin (Adam, McDuffie, Lachiewicz, Ortel, & Williams, 2013). In addition to pharmaceutical management to reduce the risk of DVT, mechanical compressive devices to the calves have been proposed as a mechanism to reduce blood pooling. However the current evidence is unclear regarding which strategy might be optimal to reduce the likelihood of a DVT (Jacobs et al., 2012). The physical therapist is a key member of the medical team who often will be the first to detect a DVT. With a DVT present, the patient might report the new onset of calf pain if not previously present or increased pain in the calf. Typically the patient will not be able to relate the onset of pain to any specific physical activity which might have caused a strain of the calf complex. Whereas traditionally Homans sign was considered the optimal way to identify a DVT, it is now evident that it is not a sensitive measure for the presence of a DVT. Recently published guidelines provide current evidence-based algorithms for the
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