Aseptic loosening Aseptic loosening can account for up to 30% of revisions of primary THAs (Melvin, Karthikeyan, Cope, & Fehring, 2014). Aseptic loosening can be caused by the release of microscopic particles from the surface of the implants due to wear and tear. These particles set off an inflammatory response that causes the nearby bone to react, weakening the bone and causing localized bone loss (osteolysis) that allows the implant to move (Rajpura et al., 2014). On X-ray, osteolysis appears as darkened areas or holes in the bone surrounding the prosthesis where the bone has seemingly melted away. As the bone adjacent to the implant weakens, there is increased movement of the implant within the bone which begins to cause pain. With a THA that uses a cemented femoral component, aseptic loosening and stress fractures can occur in reaction to low-amplitude oscillatory micromotion at the interface between the prosthetic stem and the bone cement (Saleh et al., 2016). In the case where aseptic loosening occurs, the patient may report feelings of the hip giving way or pain. Usually these symptoms develop over time and do not reduce even after the patient rests. If there is concern over loosening the therapist should contact the surgeon’s office where further assessment will Hip dislocations are a relatively common complication after THA and may occur for a variety of reasons, including surgical approach used (higher risks are associated with a traditional posterolateral incision), orientation of the implant (especially the acetabular component), use of a relatively smaller ball on the femoral component, implant type, inadequate soft- tissue tension/failure of the abductor mechanism, and poor patient positioning (Barnsley, Barnsley, & Page, 2015; Howie, Holubowycz, Middleton, & Large Articulation Study, 2012). Dislocations are most common during the first year following THA. The authors of a recent study identified that the overall dislocation rates following THA have plateaued over the time period from 1997 to 2011 in the Medicare population, with a dislocation rate of 2.84% at 6 months postoperatively (Goel, Lau, Ong, Berry, & Malkani, 2015). It is proposed by these authors that this plateau in dislocations is related to the increased use of larger femoral head diameters compared to previous smaller femoral heads. Every therapist should understand the signs of hip dislocation, which usually occurs after a sudden movement or an accident such as a fall. When the operated hip dislocates, the patient will experience pain and may feel a popping or clicking sensation in the joint. The leg will appear to be shorter and may be rotated either internally or externally. The patient is typically unable to bear weight on the dislocated limb and is unable to move the leg. If this occurs, the physician should be contacted immediately to reduce the dislocation. Malik, Jayakumar, Ul Islam, & Haddad, 2012). It can be a delicate matter to remove the failed prosthesis, and there is an increased risk of femoral fracture in addition to the usual complications surrounding a primary THA surgery. In addition, bone grafting may be required to help fixate the new hip replacement. Because of these factors, surgeons usually do not perform the revision procedure unless there is significant pain and impaired quality of life. be required. Dislocation
identification of those patients at risk of a DVT followed by the appropriate management strategies (Hillegass et al., 2016). When a therapist detects any of these signs and symptoms of a DVT, the patient’s nurse or other members of the medical team should be alerted of the findings. Depending on the policy of the institution therapy may be placed on hold until diagnostic imaging can be completed to confirm or refute the presence of a DVT. In the case where a DVT occurs outside of the acute care setting, such as a hospital, the therapist should place a call to the patient’s surgeon for further guidance before continuing PT. Infection Postoperative infection of the wound or infection deep within the new joint itself may also occur. Whereas many infections become evident before the patient leaves the hospital, some do not show up for months. Although rates vary between hospitals, it is estimated that the chance of infection is 1.5% after THA. Independent risk factors for infection include revision surgery, super obesity (body mass index > 50 kg/m 2 ), diabetes mellitus, tobacco abuse, MRSA colonization of infection, and current or prior bone cancer (Everhart, Altneu, & Calhoun, 2013). In the acute and immediate postoperative phase of the THA, the therapist should be concerned with the possibility of infection when the patient reports increased pain in the region of the hip that cannot be related to any unusual physical activity. If the incision is still in the healing phase, there may be new or additional drainage or disruption to the incision site. For patients with concerns about the incision and healing, all guidelines provided by the surgeon and his/her nursing staff should be followed. In the post-acute healing phase up to 1 year postoperatively, the possibility that a periprosthetic infection has occurred continues (Everhart et al., 2013; Mangram, Horan, Pearson, Silver, & Jarvis, 1999). During this time there will be no issues of incision drainage or disruption as can be found in the acute postoperative phase of THA. The symptom normally associated with infection at this time is pain that cannot be explained by physical activity or limb positioning. Because it is possible that the infection occurred around the time of the surgery, it is important to contact the surgeon or the medical staff for guidance on the patient returning for further assessment. Patients who have undergone THA may ask about the need to take prophylactic antibiotics when having dental work completed, and this should be confirmed with the orthopedic surgeon prior to dental work. Currently there is no substantive evidence that antibiotics are needed for all patients who are undergoing dental procedures (Zimmerli & Sendi, 2010). Revision surgery The majority of revision surgeries require the replacement of both the femoral and the acetabular components. The most common reasons for revision surgery were aseptic loosening (55.2%), dislocations (11.8%), septic loosening (7.5%), and periprosthetic fractures (6%; (Sadoghi et al., 2013). Revision surgery is a much more complicated and lengthy process than a primary THA due to the need for increased surgical exposure and subsequent soft-tissue trauma, and the risk of iatrogenic fracture with prosthetic removal and replacement (Vanhegan,
REHABILITATION
There is mounting evidence to support the role of PT in the management of patients undergoing THA where it has been shown to be efficacious prior to surgery (preoperative therapy) and then both immediately after surgery and in the post-acute phase of recovery (postoperative therapy; (Gill & McBurney, 2013; Monaghan et al., 2016; Snow et al., 2014; Westby et al., 2014).
The evidence supporting the role of PT in the management of patients undergoing THA is now being considered in emerging payment models for medical care for patients undergoing THA. Currently there is a movement away from the fee-for-service reimbursement model to payment for coordinated care delivered in comprehensive episodes of care (Froimson et al., 2013). In particular, of interest right now is the Centers for Medicare and Medicaid Services’ Comprehensive Care for Joint Replacement
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Book Code: PTNY3622B
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