Hohler, Sharon E. BSN, RN, CNOR
In 2009, approximately 285,000 total hip replacements were performed in the United States.1 Many expect this number to continue climbing due to longer lifespans and the increasing number of people with arthritis.
History of total hip surgery
Early total hip replacements used ivory implants placed into a patient's hip to relieve pain.2 Dr. M.N. Smith-Petersen implanted a glass hemisphere over the femoral head in 1925. The glass wasn't sturdy and failed, but the idea of relieving a patient's hip pain through surgery flourished. In 1936, a new metal alloy called cobalt-chromium was developed and is still used today. Dr. Frederick Thompson and Dr. Austin Moore each developed hip prosthesis implants to treat fractured hips. Surgeons found that loose femoral stems caused pain and they questioned if hip implants could be “glued” into place. The combined efforts of these and other pioneers set the stage for British surgeon Dr. Sir John Charnley's success.
Dr. Charnley is credited for developing the modern total hip replacement. In 1962, Dr. Charnley replaced an arthritic hip with a polyethylene (plastic) cup and metal femoral stem. He cemented the components in place using acrylic glue as the bone cement.3
Total hip implants
Over the past 40 years, implant manufacturers, engineers, and surgeons have worked to improve implants. Femoral stems are manufactured in a variety of metals, such as cobalt-chromium alloy, tantalum, and titanium. In the early years, surgeons glued a smooth surfaced femoral stem into place. Later, porous femoral stems were developed. The patient's bone cells were attached to the rough finish of porous implants, providing fixation.
Femoral head implants are made of cobalt-chromium metal alloy and ceramic. Acetabular components are available in metals, ultra-high molecular weight polyethylene (UHMWPE), or plastic and ceramic. There are four options of acetabular/femoral head interface: a polyethylene liner and metal femoral head, polyethylene liner with ceramic femoral head, a ceramic liner with ceramic head, and a metal-on-metal acetabulum and femoral head.4
Surgeons can implant a total hip of all porous implants, cemented implants, or a hybrid combination that involves a porous acetabulum and a cemented femoral stem. (See An example of a total hip replacement.)
Arthroplastic hip resurfacing
Arthroplastic hip resurfacing was developed in the 1990s. During arthroplastic hip resurfacing, the surgeon reams the hip socket and implants a porous metal acetabular liner by impacting it into place. The surgeon then reshapes the patient's femoral head and implants a metal cap. This cap includes a stem that fits into the femoral neck and is usually cemented into place using polymethylmethacrylate cement. This procedure is generally performed on younger patients who want to continue a high level of activity and may face a future revision hip procedure. (See Normal hip joint.)
European surgeons have been performing hip resurfacing procedures since the 1990s. The FDA approved this procedure in 2006, and three companies now offer this option.5 The FDA website provides comparison diagrams of both metal-on-metal arthroplastic hip resurfacing implant and a metal-on-metal total hip implant at http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/ImplantsandProsthetics/MetalonMetalHipImplants/ucm241601.htm.
The advantages of hip resurfacing include a more stable joint with a decreased dislocation rate, better range of motion, smaller leg length discrepancy, and less bone loss because the femoral head isn't removed. The major concerns with this procedure include risk of femoral neck fractures and concerns about metal particles shed when the patient moves the hip. This procedure has gained much attention, but according to the American Academy of Orthopaedic Surgeons, “it is too early to assess the long-term success of this procedure.”6
Figure. Normal hip j...Image Tools
Changes in surgical incision techniques
During the past decade, the minimally invasive surgical (MIS) incision techniques shortened hip incisions from 10 to 12 in (25.4 to 30.5 cm) to approximately 4 in (10.1 cm). The benefits of MIS include less soft tissue trauma, less postoperative pain, and quicker recovery. Many surgeons have worked at precise, shorter incisions that resulted in these benefits.
Surgeons may use one of several incision techniques when performing a total hip procedure. Three commonly used incisions are the posterolateral, the anterolateral, and the two-incision anterior approach. The newest incisional approach involves one anterior incision. The posterolateral approach incision is positioned over the posterior 1/3 of the greater trochanter and extends toward the posterior superior iliac spine.7 The posterolateral incision involves the hip capsule at its thinnest, weakest area, increasing the risk of dislocation. Surgeons overcome this complication by correct implant positioning, options of larger femoral heads, elevated rim acetabular liners, strong capsular repairs, and patient teaching of hip precautions.
The Modified Hardinge anterolateral approach gives excellent acetabular exposure. In this approach, the surgeon makes a curving incision through the gluteus medius and vastus muscles. The Modified Hardinge approach should be considered in any patient who will have difficulty following the normal precautions following surgery. The use of a sterile hip drape with pouch helps keep the leg draping sterile when the leg is flexed and externally rotated during the Modified Hardinge surgical approach.8
The two-incision anterior incision approach involves the surgeon making one anterior groin incision to prepare and insert the acetabular implants and the second incision posterolateral to ream, prepare, and insert the femoral stem. Early results promised rapid recovery for patients but, complications did occur, such as femoral fracture, nerve palsy, dislocation, and infection.9
The newest incision involves one anterior groin incision. As with the two-incision approach, the surgeon goes between muscles and uses fluoroscopy to ensure correct placement of implants. Surgeons who master this technique highlight its benefits, such as decreased pain and quicker recovery because muscles aren't cut; however, OR team members and the hospital must invest time and effort to achieve quality outcomes.10
Innovations focus on three things: a continued search for stable implants that will last longer; the patient's experience going through a joint procedure; and techniques that enhance healing and best patient outcomes.
Implants that increase stability
Dislocation of the total hip has been a complication since the early days. Surgeons and implant companies address this issue in several ways. Implant companies offer larger femoral head implants that are more difficult to dislocate. Many surgeons believe a 36 or 40 mm femoral head gives more stability than a 26, 28, or 32 mm head. In the past, larger femoral head implants caused concerns regarding wear of the polyethylene liner. The larger heads required more room and necessitated thinner liners. As the liner wore, plastic particles were shed and resulted in osteolysis (bone loss) and loosening of components, a failed total joint. Researchers are showing that highly cross-linked polyethylene liners (HXLPE) decrease wear rates and osteolysis. These results encourage surgeons to implant large, more stable head implants with the highly cross-linked liners.
Another option in preventing the dislocation complication involves elevated-rim polyethylene liners. These elevated rim liners have a built-up area on the inside surface, which inhibits the femoral head from dislocating.
Another stability option involves modular neck implants. Most femoral stem implants include the neck portion. At least two implant companies have developed a modular system with neck choices of standard, antegrade, and retrograde. After the surgeon implants the femoral stem, he or she attaches the neck implant via Morse taper. A Morse taper involves a conical press-fit fixation.11 The tapered bottom of the neck implant fits into the socket of the stem, and cold welds together when implanted.
Longer lasting implants
The probability of a hip replacement lasting 20 years is approximately 80%.12 Many expect these statistics to improve with current innovations.
Metal-on-metal hip implants promise improved wear rates: 20 to 100 times less than metal-on-conventional polyethylene.13 These finely machined implants offer increased lifespan of the acetabular-femoral head interface. However, there's concern about metal particles produced when the person moves his or her hip joint. Surgeons question whether metal particles will cause localized damage and contribute to loosening of the prosthesis. Physicians have found that patients who have metal-on-metal implants often show increased levels of cobalt and chromium ions in their urine and blood. They question whether these metal ions will produce a hypersensitivity to the metals or whether they can cause a malignancy.13
The FDA issued a public health communication about metal-on-metal implants in February 2011. They recommend that surgeons not implant metal-on-metal implants in females of childbearing age, people with known sensitivity to cobalt, chromium, or nickel, patients with renal insufficiency or decreased immunity, and those taking high doses of corticosteroids.14 In May 2011, the FDA began a post market surveillance study about metal-on-metal implants.
One new total hip implant metal is called trabecular metal and is made from tantalum. Trabecular metal has a finish similar to human trabecular bone, and engineers believe human bone will grow into trabecular metal easily and hold it firm. “Ceramic heads are harder than metal and are the most scratch resistant implant material.”15 In 2011, a 20-year study showed an 88% survival rate for ceramic-on-ceramic implants.16
Manufacturers of cross-linked UHMWPE liners improved upon the conventional liners. Two methods used to cross-link these liners include exposing them to vitamin E and irradiating them with gamma rays. A 2009 study compared highly cross-linked versus conventional polyethylene acetabular components for 100 patients. At 5 years postoperatively, the highly cross-linked components showed femoral head wear was significantly lower than that associated with a conventional polyethylene liner.17 An overview of 28 studies that involved 1,503 patients after hip arthroplasty agreed that HXLPE show less wear, and the risk of osteolysis decreased by 87% when compared to conventional polyethylene liner components.18
For patients with metal (nickel, cobalt, and chromium) allergies, titanium stem and acetabulum components are available. Ceramic head implants provide a metal-free femoral head.
Figure. An example o...Image Tools
Current innovations in the patient experience
Saint Francis Medical Center in Cape Girardeau, Missouri, has incorporated a program and set up a Center for Excellence (joint camp) in the dedicated total joint unit. The Marshal Steele program adds value and evidence-based practices.19 The philosophy begins by making the patient the focus for all activities during his surgery and hospital stay. Another emphasis says each patient is a relatively healthy person undergoing a total joint surgery to improve his or her lifestyle. Patients receive their preoperative teaching in group sessions. Patients who are scheduled to have their surgery on the same day meet in the preoperative “joint camp” classes. The instructor tells them what to expect throughout their hospital stay. During the postoperative phase, they have the opportunity to socialize and become friends as they exercise and do therapy times together.
Another important part of the joint camp is a coach. Each patient has an opportunity to have a coach (family member or friend) who goes through the experience with them. The coach can attend preoperative classes and stay overnight in the patient's room to provide company and act as a patient advocate. The coaches also encourage patients as they exercise. The joint camp has reunions periodically where graduates can return to visit.
“Prehab” conditioning refers to preoperative conditioning that the patient works to achieve before surgery. When dealing with arthritis pain, many patients stop exercising. During the prehab sessions, patients learn exercises and build fitness in their bodies, which helps in their postoperative rehabilitation.
Improved patient outcomes
Improved pain management contributes to recovery. Some surgeons will request a single epidural morphine injection for their patients in the preoperative holding room. A study conducted by Viscusi and colleagues showed that extended-release preservative-free epidural morphine injection (without an indwelling catheter) gave patients significant pain relief for the first 48 hours after their total hip surgery.20
One study involved 64 patients undergoing a total hip arthroplasty who received either a “periarticular intraoperative multimodal drug injection or no injection. All patients received patient-controlled analgesia (PCA) for 24 hours after surgery. Periarticular intraoperative injection with multimodal drugs can reduce postoperative PCA requirements and pain on activity in patients undergoing total hip arthroplasty (THA) with no apparent increase in risk.”21
Outpatient and 23-hour total hip procedures can have successful results. A group of 69 patients (younger than 65 years) participated in a California metropolitan outpatient THA study, and 53 (77%) of the 69 went home the day of surgery. There were no medical readmissions and no complications, such as wound drainage, infection, or dislocations. Six weeks after their surgery, 50 of 52 patients who completed a satisfaction questionnaire reported they were pleased with the decision to go home the day of surgery.22 Another outpatient total hip protocol was established at Rush Medical Center in Chicago. This program involves comprehensive teaching, which begins preoperatively and continues through postoperative physical therapy. Prevention of pain begins preoperatively with epidural anesthesia and continues with postoperative ketorolac and oral opioids when the patient can tolerate oral medications.23
Platelet-rich plasma to improve healing
Platelet-rich-plasma (PRP) promises improved healing. PRP technology involves a patient's own blood being drawn, centrifuged, and separated into the concentrated blood cells and plasma (platelet-poor plasma or PPP). The surgeon applies the PRP concentrate to the patient's tissues. Some surgeons apply the PRP concentrate to the prepared bone before implanting the porous implants. The PPP component can be delivered to the joint tissues and skin during closure of the surgical wound.
The American Academy of Orthopaedic Surgeons sponsored a PRP forum in 2011 to evaluate the effectiveness of PRP. The forum looked at total joint arthroplasty and PRP usage. In 2011, the American Academy of Orthopaedic Surgeons reported that PRP used during total knee surgery resulted in decreased blood loss and less need for pain medications postoperatively. Those patients were also discharged earlier from the hospital. Lab tests confirmed that PRP helps fight both Gram-negative and Gram-positive bacteria.24
In 2012, the American College of Chest Physicians (ACCP) updated their recommendations for preventing venous thromboembolism (VTE) in total hip replacement (major orthopedic surgery) patients.25 VTE encompasses both deep vein thrombosis (DVT) and pulmonary embolism (PE). These recommendations can be found at http://journal.publications.chestnet.org/article.aspx?articleid=1159399# PreventionofVTEinOrthopedicSurgeryPatients. Low-molecular-weight heparin (LMWH) is the first choice drug for VTE prevention. Other VTE drug options include fondaparinux, apixaban, dabigatran, rivaroxaban, low-dose unfractionated heparin, vitamin K antagonist, or aspirin. If LMWH is used prophylactically, the recommended start time has been changed to 12 hours or more (instead of 4 hours) preoperatively. If the LMWH isn't started until after the procedure, the recommended time is 12 or more hours after surgery (versus 4 hours postoperative).25
The ACCP recommends both antithrombotic drug therapy and use of intermittent, pneumatic compression devices (IPCDs) during the hospital stay and upon return home. The recommended time frame for use of the IPCD is 18 hours a day. Recommendations also include the use of a portable, battery-operated device that can record and report appropriate IPCD wear time.25 The time frame for postoperative VTE prophylaxis during the outpatient period has been expanded to up to 35 days after surgery (instead of 10 to 14 days).25
Preoperative patient teaching must include DVT risk factors and how to prevent this complication when patients go home. The perioperative nurse needs to teach the patient how to take prescribed medications, the importance of associated monitoring, signs and symptoms of DVT and PE, and how to seek medical help if these occur.
A study reported in the September 2010 issue of the Journal of Bone and Joint Surgery looked at 67,469 Danish patients who had a THA performed over a 10-year period.26 Within 90 days of their total hip replacement, 1% of the patients (even with pharmacologic thromboprophylaxis) suffered a DVT or PE. The researchers found that patients with a history of prior VTE or cardiovascular disease faced an increased risk when compared with patients without that history.26 Surprisingly, patients with rheumatoid arthritis have a lower risk of VTE than patients with osteoarthritis.
Improved efforts to prevent infection begin with a patient in his or her best possible health prior to surgery. Many surgeons will cancel surgery if the patient presents with signs and symptoms of an infection (such as a swollen, reddened toenail or a urinary tract infection). An underlying infection could result in a surgical site infection and compromise the patient's outcomes post-surgery.
Routine measures include having the patient take a shower with bacteriostatic soap the night before surgery. Perioperative patient education should teach patients and family caregivers of the importance of hand washing and how to care for the surgical wound.
Keeping blood glucose within a normal range
A normal blood glucose decreases a patient's risk of infection. A 2011 study included 1,948 patients who had elective primary total hip or knee arthroplasty from 2000 to 2008. One hundred and one (out of 1,948) patients developed a postoperative infection within 2 years of surgery. Twenty-two percent of those patients with infection had diabetes when compared to 9% of the patients with infections without diabetes. On postoperative day one, a blood glucose level greater than 200 mg/dL doubled the risk of infection for the patients with diabetes. The researchers found that high blood glucose levels contributed to postoperative infections for all patients. Elevated blood glucose (greater than 140 mg/dL) on postoperative day one in patients without diabetes tripled their risk of developing an infection.27
A 2011 Academy of Orthopaedic Surgeons press release discussed a study involving 121 primary total joint procedures. Their findings agree that patients with either low or high blood glucose levels preoperatively had increased complications, longer length of hospital stay, and increased hospital costs.28
Keeping surgical patients warm prevents complications
Hypothermia is defined as body core temperature at or below 96.8o F (36o C). “Perioperative hypothermia can result in three times the incidence of surgical site infection, increased bleeding and need for blood transfusions, three times the risk of cardiac complications, a higher risk of developing pressure ulcers, and prolonged recovery after surgery.”29
Keeping surgical patients warm can be achieved by using a forced-air warming blanket, circulating warm-water devices, and conductive warming devices. Other methods to conserve body heat include infusing warm I.V. fluids, increasing the room temperature in the OR, and covering the patient with warm blankets while minimizing exposed areas of the body.
Surgical care improvement project measures
Evidence-based behaviors contribute value to a patient's excellent outcome. The Surgical Care Improvement Project (SCIP) brought together leading physicians and nursing groups, government agencies, and related business groups with the goal of helping to reduce surgical mortality and morbidity through collaborative efforts.30 The SCIP measures involving THA take into account the following:
* Proper timing of preoperative antibiotics improves patient outcomes. Antibiotics must be given within 1 hour prior to the incision (2 hours for vancomycin or a fluoroquinolone).
* Selection of appropriate preoperative antibiotics varies for specialties. The appropriate orthopedic antibiotic is cefazolin or cefuroxime if the patient has no allergy to beta-lactam antibiotics (penicillin family allergy). If the patient has this allergy, the antibiotic is vancomycin or clindamycin.31
* Prophylactic antibiotics must be discontinued within 24 hours after surgery end time.
* If hair removal is needed, it must be appropriate: done in the preoperative holding area using an electric clipper—not a razor—and it should be performed shortly before the surgical procedure.
* Any urinary drainage catheter inserted during the hospitalization should be removed on either postoperative day 1 or 2.
* Surgical patients' body temperature will be maintained within a normal range. The patient's body temperature must be at 96.8o F (36o C) within 30 minutes prior to or 15 minutes after anesthesia ends. If an active warming device was used on the patient, this criterion is met.
* A patient who routinely takes beta-blocker medication should receive his or her usual dose before surgery.
* DVT prophylaxis is accomplished during the perioperative period (within 24 hours before to 24 hours after surgery).32
The 2013 AORN Perioperative Standards and Recommended Practices referenced three studies, which all concluded that mechanical DVT prophylaxis benefits patients undergoing total hip surgery.33 The recommended practice for prevention of DVT starts with an institution-wide program. Many disciplines (physicians, RNs, pharmacists, anesthesia care providers, and other pertinent staff) should participate in a comprehensive DVT program. Each patient should be assessed preoperatively and contraindications ruled out before appropriate mechanical DVT devices are applied. Correct application and operation of mechanical DVT devices (intermittent pneumatic pressure devices and graduated compression stockings) help keep the patient safe from DVT complications. Nursing documentation gives pertinent information about the DVT prevention practices used for each patient. Pharmacologic prevention of DVTs involves proper and safe medication administration. Patients and their caregivers need to be taught about all medications, including DVT preventive medications before they leave the facility. Such details include how to take the medication safely, adverse reactions to report to the surgeon, and follow-up appointments and needed lab work. The AORN recommendations give comprehensive information about a DVT prevention program.
Total hip procedures relieve pain and improve mobility for many people. Since Dr. Charnley pioneered total hip replacement surgery in 1960s, physicians and implant companies have continued to search for improvements and innovations. These companies design more stable total hip implants, which decrease the risk of dislocation and search for implants that will last each patient's lifetime, not just the 20-year longevity of the past. Medical centers incorporate programs such as Centers for Excellence (joint camps), which improve the patients' experience. Knowledgeable nursing and medical staff practice behaviors that promote healing and best patient outcomes. These current innovations add value and quality to THA.
© 2014 by Lippincott Williams & Wilkins, Inc.